MPHY3000/MPHYM000: Medical Physics Projects 2013/14

Below is a list of Medical Physics projects being offered for undergraduate students in the Department. To find out more about a project and/or to indicate your interest in taking it, please email the first supervisor by clicking on his/her name.

Deadlines

  • A Project Outline is due on Monday October 14, 2013. Your supervisor must also complete a Project Risk Assessment Form. Students are required to hand in the form with two copies of their outline to Mohini Nair in the Medical Physics Departmental Office (second floor of the Malet Place Engineering Building).
  • Project Progress Reports are due by Monday January 20, 2014. Two copies should be handed to Mohini Nair in the Medical Physics Departmental Office.
  • Project talks will be held on Wednesday March 19, 2014 in Rooms 1.19 and 2.14 of the Malet Place Engineering Building.
  • Final Reports are due by Friday March 28, 2014. Please hand in two copies to Mohini Nair in the Medical Physics Departmental Office.

Project information

Cervical cancer in sub-Saharan Africa

Supervisors: Prof. Gary Royle and Dr. Paul Burke

Student: Robyn Sweeney

Cervical cancer is a major cause of death in sub-Saharan Africa, whereas it is largely eradicated in the UK through vaccination and screening programmes. This project will collate patient cohort statistics for Ghana and Nigeria, relate to geographic and economic factors, and to the distribution of available diagnostic and screening facilities. The project will prepare information for young women in these countries to raise awareness.

The application of a relative biological effectiveness model to proton therapy planning

Supervisors: Prof. Gary Royle and Catarina Veiga

Student: Edward Simth

Radiotherapy treatment planning is conventionally based upon the physical radiation dose. However, there is a complex relationship between physical dose and the preferred form of cancer cell death. The relative biological effectiveness (RBE) is a parameter that partly intermediates. RBE calculations for proton therapy are an unsolved problem, but it is generally understood that the planned dose map and the apoptosis (preferred cell death mechanism) distribution significantly differ. This project will apply RBE models to planned proton therapy treatments to quantify the effect of different models and RBE values.

Phantom design for x-ray diffraction evaluation in breast cancer

SupervisorsProf. Robert Speller and Christiana Christodoulou

Student: Eddie Tang

The aim of this work is to design, test and manufacture phantoms for breast cancer research with a range of different materials of interest and study their diffraction profiles in energy dispersive X-ray diffraction. This will involve the student to use equipment in Make Space for fabricating the experimental phantoms.

Quantifying contrast medium washout

Supervisors: Prof. Robert Speller and Dr. Dan O'Flynn

Student: Lucca Kalafatis

In the early stages of cancer immature blood vessels are formed. These vessels ‘leak’ and the effect of this is to alter the washout of previously administered contrast medium. This project is to look at measuring this washout using a new technique of multi-spectral X-ray imaging based around pixelated energy resolving detectors. The project is experimental but will require some computing to analyse the data from the detector system.

Image guided, adaptive proton therapy

Supervisors: Dr. Jamie McClelland and Catarina Veiga

Student: Peter Bruton (MSc student)

University College London and its partner hospital are building a highly advanced clinical proton therapy (PT) facility, which will be operational in 2017. PT is an advanced form of radiotherapy (RT) capable of providing a dose map which conforms much better to the shape of the tumour and gives a lower dose to surrounding healthy tissue than conventional RT. However, a problem with PT, as with conventional RT, is accounting for changes to the patient during the course of therapy, which can last several weeks. UCL, together with UCLH, has recently developed an advanced image registration based framework for studying the dosimetric effects of changes to the patient during therapy. This uses weekly cone-beam computed tomography (CBCT) scans acquired of the patient setup in the treatment position to image changes to the patient’s position and anatomy. Deformable image registration is used to map the patient’s anatomy and dose distributions between different scans. This method is now undergoing clinical studies at UCLH for patients undergoing conventional RT treatment. This project will investigate applying the same methodology to PT treatments where the dosimetric impact of changes to the patient has yet to be studied. This project will require a basic understanding of RT and PT and how the treatment is planned and delivered, and the ability to analyse data and program in MATLAB. It is not essential the student has all these skills at the start of the project but they must be eager to learn them.

Exploration of the implementation of combined magnetic resonance and optical methods for assessment of brain metabolism and haemodynamics: application to a preclinical model of birth asphyxia

Supervisors: Dr. Ilias Tachtsidis and Dr. Bart Hoogenboom (LCN)

Student: Lukas Beichert

Perinatal cerebral hypoxic-ischemia (HI) is a condition resulting from reduced oxygen delivery or/and blood flow occurring either in utero or during delivery. It occurs in 1 to 2 per 1000 live births and can result in physical or sensoreal handicap or fatality. Although there are significant advances in the treatment of asphyxiated babies, little is known about the effects of these neuroprotection strategies on brain blood perfusion and metabolism following HI. This project is part of an exciting collaboration between the Perinatal-Brain Magnetic-Resonance Group at UCH and the Biomedical Optics Research Laboratory at UCL that aims to deliver novel measurements to investigate the effects of brain neuroprotection through combination of magnetic resonance and optical (near infrared) technologies. The main aims of this MSc project are to (1) assist in experimental data collection; and (2) to analyse imaging, perfusion and metabolic data, from the optical instruments, obtained from piglet brains in-vivo after HI. The student will learn how to operate the optical instrument and use novel software tools that will allow quantification of the optical measurements and then will focus on analysing those in conjunction with the magnetic resonance imaging & spectroscopy measurements. The larger scope of the analysis is to investigate the benefits of implementing treatment in birth asphyxiated infants. This project would be suitable for a student with an interest in optical technologies, physiology/pathophysiology, brain tissue biochemistry; and will involve data collection, data processing and some statistical analysis.

Investigating the measurement of brain tissue light scattering in traumatic brain injury patients

Supervisors: Dr. Ilias Tachtsidis and Dr. David Highton

Student: Alison Tucker

Monitoring the tight balance of brain blood flow, oxygen delivery and brain tissue metabolic rate is a major aim in patient diagnosis and care. A patient’s health is in great danger when there is a prolonged lack of oxygen delivery to meet the metabolic demand of the tissue; for example in traumatic brain injury. To achieve these measurements we have developed and use optical systems based in near-infrared spectroscopy technology that can resolve the major oxygen dependent chromophores (haemoglobin) by quantifying the changes in light absorption. Recently and as part of an on-going collaboration with Hamamatsu photonics (Japan) we have access to a state-of-the-art optical system that can quantify independently brain tissue light absorption and light scattering. These two independent light measurements are affected by different components and processes in the tissue. As part of this project the student will investigate how the light tissue scattering signal of the brain is affected and evolves in traumatic brain injury patients during hospitalisation. It is of particular interest the effect of brain oedema and brain ischaemia will have in light scattering. This project is a mixture of experimentation and signal/statistical analysis. This project will take place at both (i) the Biomedical Optics Research Laboratory at UCL the UK’s leading research group in biomedical optics, which offers expertise and facilities in optical instrumentation and methodologies and (ii) the National Hospital for Neurology and Neurosurgery where patient’s recruitment will be done.

Measuring blood flow and oxygenation on exposed spinal cord in a multiple sclerosis preclinical animal model

Supervisors: Dr. Ilias Tachtsidis and Dr. Andrew Davies

Student: Jack Clarence-Smith

Measuring the tissue blood flow and the oxygen levels for an organ allows us better understanding of the physiological status of that organ. This is important during pathology when disease can affect the organs tissue blood flow and oxygenation. For example in Multiple Sclerosis (MS) there is evidence to suggest that inflammation areas suffer from inadequate oxygenation. The oxygen shortage, termed hypoxia, is severe enough to cause two of the important problems in MS: loss of function (causing symptoms such as paralysis,) and damage to the cells that put the insulation (myelin) on the nerve fibres, resulting in demyelination. While the hypoxia is clearly important, we do not know whether it is due to a reduced blood flow, or an increased demand for oxygen, or both. To investigate this we propose to use novel state of the art photonic systems that can measure (i) blood flow changes by utilising laser Doppler technology and (ii) oxygenation by utilising near-infrared spectroscopy. The student will be using these photonic systems on the exposed rat spinal cord before and after inflammation has been induced. In particular the student at the beginning will be using a state of the art laser Doppler instrument from Moor Instruments to collect flow data on the exposed spinal cord and identify the physiological changes that MS induces. Following that the student will modify and use a recent developed broadband near-infrared spectrometer that will allow to measure oxygenation and metabolism as well. This project is a mixture of development, experimentation and analysis. This project will take place at both (i) the Biomedical Optics Research Laboratory at UCL the UK’s leading research group in biomedical optics, which offers expertise and facilities in optical instrumentation and methodologies and (ii) the UCL Department of Neuroinflammation that investigates multiple sclerosis (MS) with a broad range of research from basic neuroscience to clinical translation, including therapeutic trials.

Design of an EMG amplifier for a closed-loop implantable stimulator for experimental treatment of spinal cord injury

Supervisors: Dr. Clemens Eder (EE) and Prof. Nick Donaldson (MedPhys)

Student: Joanne Ting Chu En

The Implanted Devices Group (Medical Physics) and the Analogue Systems Group (Electronic Engineering) are involved in an EU project in which epidural stimulation of the spinal cord is to be tested as a therapy. One new experiment is called “Social Rats” because the stimulation will be applied while the rats are free to move around in a cage and interact socially with other rats. Making an implanted stimulator which is small enough and can withstand the movement made by the rat is difficult. A PhD student (Vasso Giagka) is hoping to meet these requirements by making the epidural electrode array with an embedded custom integrated circuit. The implant will also have some subcutaneous electronics and a head connector. The subcutaneous electronics will include a rechargeable battery and a programmable microcontroller. The program includes the stimulation parameters, such as pulse frequency and amplitude. In this way the battery can be recharged and the program modified while the rat is asleep but the rat will be unhindered when out in the social cage. This project is about the design of the sub-cutaneous part of the implant system. Specifically it will entail the following developments:

• Design of the EMG amplifiers that detect muscle activity. These amplifiers must have the appropriate pass-band, use few components and little power.

• The microcontroller must be chosen: it must be as small as possible yet have the required functions. One such will be tested with an existing (or slightly-modified program) to show that it can use the EMG signals to change the stimulation while the animal is walking.

• A type of rechargeable batteries must be chosen. The range of available cells will be investigated and samples bought and tested with a purpose-built charger-discharger.

• The implant will be designed (lay-out) to see whether it can be made small enough.

The work is mostly electronics. The device will be part of the whole system, including the non-implanted computer and the implanted “active” electrode array.

Artificial larynx

Supervisors: Prof. Nick Donaldson and Dr. James Graveston

Student: Sabrina Lister

This project will only be suitable for a student who can use the equipment in Make Space for fabricating the experimental valves. This is a project to show that EMG control works for patients with bilateral vocal cord palsy. We aim to make an EMG-controlled tracheostomy valve. When the valve is open the patient breaths through the tracheotomy, with it closed the air is diverted up to the paralysed cords making speech. This would be a good way of showing that the EMG control works in a non-invasive and safe way. So the project would be to get as far as they can with: (i) Design and make the valve; (ii) control the valve in real time; (iii) Test it on a patient. Here is the specification for the valve:

1) It should fit onto a standard push fit tracheostomy tube end (they should all be the same size so you can attach a ventilator to them if required, though that needs to be checked).

2) It should be easy to remove (less than 5s).

3) Size is not an issue as the patient can be sitting with the valve supported.

4) It should provide very little airway resistance when open and a large resistance when closed (<100ml/min). Open and close should be fairly fast (~100ms).

5) It MUST fail safe (i.e. can't get stuck closed and nothing can be aspirated). 

6) There will be some pressure requirements it has to meet but remaining competent with +/- 0.5 atmospheres across a closed valve is plausible.

We envisage something along the lines of a T piece where the leg of the T connects to the Tracheostomy tube and the cross piece is open to the air. At the junction between the cross piece and the leg you have a solenoid which closes the exit to the leg when it is energised. Safety is of paramount importance.

Test rig for an artificial larynx

Supervisors: Prof. Nick Donaldson and Dr. James Graveston and either Luke Donne or Gemma Bale (for Labview).

Student: Phoebe Tsang

Another student is to make an EMG-controlled tracheostomy valve. We want to show that this works properly so the test rig is to allow the EMG, pressure-across-the-valve, and the air flow rate to be monitored, plus any other signals that appear to be interesting as the valve design advances. The valve should be tested over the whole range of likely conditions, not only while the patient is using it as we hope, but also if breathing is not correctly coordinated with the valve opening or closing, but also under other conditions such as coughing and sneezing. To achieve this, the apparatus is likely to need some sort of pump to generate the pressure and air flow, plus pressure transducers. It may be convenient to run the test, display the measurements and record the results using Labview.

Measuring pedal forces while cycling

Supervisors: Dr. Anne Vanhoest (IOMS) and Prof. Nick Donaldson

Student: Samuel Hunt

The aim of the project is to instrument the pedals of a tricycle so as to measure the radial and tangential forces produced. The transducers have been bought but never used. The initial part of the project would include: mounting the transducers; obtaining signals at the recording computer (signals are transmitter by wireless link from the rotating crankshaft); calibration; and displaying the results in graphical form. After this, the set-up can be used for experiments on biomechanics or ergonomics. Tangential forces at the pedals do no useful work (propelling the trike) but might be present due to the limitations of the legs (as musculo-skeletal machines) or because forces must also be produced to keep the feet on the pedals. A possible experiment would be one in which we measure the forces with ordinary pedals, and pedals with clips, compare the pedal forces, and compare the oxygen consumption at equal power output.

Humidity calibrator

Supervisors: Prof. Nick Donaldson and either Dr. Anne Vanhoest (IOMS) or Dr. Clemens Eder (EE)

Student: Thanh Phong Phan

This project is suitable for a student with practical skills because it involves developing a system and prototypes will have to be made by the student. Experience will also be gained in data-logging, experiment design and presentation of experimental results. In the Implanted Devices Group, we have developed a humidity sensor that is fabricated on an integrated circuit that will be part of future very small implants. We need to measure the drift of these sensors as they age, and so we want to run a long-term test with sensors at constant humidity and temperature. We started such an experiment in 2012: boxes contained the sensors and, at the bottom of each, there was a saturated salt solution. We expected this to fix the humidity but the sensor signals appeared to drift quickly. We found a reference which said that in such an apparatus, the air may become stratified, and therefore not constant humidity throughout. This is a project to develop a satisfactory constant-humidity chamber for a new experiment. Tests will be done with many bought sensors placed in boxes so as to investigate the uniformity of the humidity, how it changes with time, and how it depends on external factors (e.g. sunlight). It may be necessary to mix the moist air with a fan and also to agitate the solution. We want to be able to define several humidities from quite dry to quite moist (e.g. 20 to 80% RH).

Comparing tissue magnetic susceptibility values obtained by MRI-based susceptibility mapping with those measured by SQUID magnetometry

Supervisors: Dr. Karin Shmueli and Dr. Paul Southern

Student: Sarah Hussain

There has been a recent explosion in the use of magnetic resonance imaging techniques (MRI) to map tissue magnetic susceptibility. Susceptibility is a tissue property that determines how easily and strongly the tissue can be magnetised by the very high magnetic field found inside an MRI scanner. MRI susceptibility maps reveal valuable new information about tissue microstructure and composition such as its iron and myelin content. This contrast is proving useful to study diseases such as Parkinson’s disease (in which iron accumulates in deep-brain regions) and Multiple Sclerosis (that involves demyelination). One drawback of MRI-based susceptibility mapping is that the required image processing steps affect the susceptibility values obtained so that we can only map relative tissue susceptibilities. This means it is important to compare MRI-based susceptibility values with independent measures of tissue magnetic susceptibility. One of the most accurate susceptometry techniques uses a highly sensitive magnetometer built from a superconducting quantum interference device (SQUID).  SQUID magnetometers measure small changes in tissue magnetisation as the magnetic field is changed so that accurate absolute ‘gold-standard’ susceptibility values can be calculated. The aim of this project is to compare susceptibility values measured by MRI susceptibility mapping with those obtained by SQUID magnetometry for samples of fixed tissue. This will allow us to determine the true accuracy and precision of MRI susceptibility mapping techniques as well as giving insight into the sources of magnetic susceptibility in different tissues. The student will calculate and compare susceptibility values from SQUID and MRI measurements of several different tissue samples.

Developing ultrasound and phase contrast x-ray imaging phantoms with 3D polymer printing

Supervisors: Dr. Adrien Desjardins and Prof. Alessandro Olivo

Student(s): Azalea Khan

Ultrasound imaging is increasingly used to guide minimally invasive procedures in the human body. This imaging modality has many advantages, such as being real-time and non-ionising, but it can be challenging to interpret images and to plan an optimal path to the tissue target. There is an urgent need for better training tools for a wide range of patient anatomies. This project will involve creating an ultrasound phantom for percutaneous (needle-based) procedures in the spine and/or the upper arm. In particular, it will involve digitally segmenting 3D image volumes and creating polymer/silicone structures using cutting-edge 3D printing techniques. This project, which is co-supervised by an Anaesthetist at UCL Hospital, is an opportunity to gain hands-on experience with both medical image processing and ultrasound imaging in clinical practice. Two students can be accommodated on this project.

Ultrasound imaging phantoms with 3D polymer printing

Supervisors: Dr. Adrien Desjardins and Dr. Simeon West

Student(s): Wenjie Zhu

Ultrasound imaging is increasingly used to guide minimally invasive procedures in the human body. This imaging modality has many advantages, such as being real-time and non-ionising, but it can be challenging to interpret images and to plan an optimal path to the tissue target. There is an urgent need for better training tools for a wide range of patient anatomies. This project will involve creating an ultrasound phantom for percutaneous (needle-based) procedures in the spine and/or the upper arm. In particular, it will involve digitally segmenting 3D image volumes and creating polymer/silicone structures using cutting-edge 3D printing techniques. This project, which is co-supervised by an Anaesthetist at UCL Hospital, is an opportunity to gain hands-on experience with both medical image processing and ultrasound imaging in clinical practice. Two students can be accommodated on this project.

Technology transfer opportunities for carbon nanotubes

Supervisors: Dr. Adrien Desjardins and Lucy Jennings (UCLB)

Student: Pritum Hirani

Recently there has been great interest in the application of carbon nanotubes (CNTs) to medicine. With optical and electrical properties that are desirable in many contexts, CNTs could have applicability in several clinical fields. This project, which is based on the student’s interest in technology transfer, is focused on exploring the applications of CNTs to medical devices. It will involve three components: a) analysing the  intellectual property landscape; b) identifying specific medical devices and clinical applications where CNTs could be relevant; c) detailing the potential paths to clinical translation and the corresponding challenges.

Quantitative and qualitative analysis of friction between volar forearm and non-woven materials for the development of incontinence maintenance

Supervisiors: Prof. Alan Cottenden and Sabrina Falloon.

Student: Will Roberts

Rubbing between fabrics and skin can cause abrasion damage. In the case of everyday clothing this might just result in a little soreness and mild discomfort but in the more extreme conditions found between an incontinence pad and skin, damage can be more serious with significant erosion of skin barrier function. But friction between fabrics and skin is poorly understood, hampering the design of products which are less damaging. The aim of this project is to analyse an existing set of friction measurements between the inner forearm of 17 women (aged 26-95) and a range of fabrics and interpret the data in terms of video footage of all the experiments to gain insights into how and why friction varies between different fabrics and different people’s skin.

Evaluation of the performance of a new commercial Electrical Impedance Tomography system in liquid filled tanks

Supervisors: Prof. David Holder and James Avery

Student: Hugo Wigginton and Jordon Kent

EIT is a novel medical imaging method, with which images of the electrical impedance of the head can be produced with a box about the size of a paperback book, laptop  and EEG electrodes on the head.  It is portable, safe, fast and inexpensive.  The supervisor’s research has been to develop its use in imaging functional activity in the brain. Applications include imaging during epileptic seizures or in acute stroke. Until this year, all EIT systems were individually built in research laboratories but now a commercial system, the Swisstom, has become available. The signals for producing EIT images are small and at the limit of detectability, especially for imaging in the head, and this system has not yet been evaluated for this application. The purpose of the project will be to determine the performance of this new system using anatomically realistic liquid filled tanks, printed to resemble the adult and neonatal human head with skull. It will be assessed both for differences over time as in epileptic seizures, and for “one-off” imaging, as for acute stroke. Technical factors, such as the pattern of applied currents may then be modified in order to improve the performance. The output will be a feasibility analysis of whether the system is suitable for these applications, with recommendations for any needed improvement. Skills to be acquired will include one or more of: medical image reconstruction; familiarity with EIT systems and their use; programming in Matlab; experimental design and data analysis. The project is suitable for a student with a background in physics, engineering, computing, or a medical student with an interest in learning technical skills and programming.

Acousto-optic imaging of tissue mimicking phantoms

Supervisors: Dr. Terence Leung and Prof. Jem Hebden

Student: Andrea Diallo

Acousto-optic (AO) imaging is a novel technique that exploits both light and ultrasound to perform 3D imaging of blood oxygenation. It can potentially be used for breast and brain imaging. An AO imaging system is currently under development in the Biomedical Optics Research Laboratory. This project involves a) making a phantom which has similar optical (colour) and acoustic (stiffness) properties as real human tissue, and b) performing AO imaging experiments with the tissue-mimicking phantom. The objective is to image a colour object embedded in a turbid medium and assess the performance of the technique. While the basic experimental setup is fixed, the student needs to design the configuration to optimise the imaging performance. The project will suit a student who has interests in model making, scientific measurement, and data analysis.

Development of a smartphone app for jaundice screening

Supervisors: Dr. Terence Leung, Dr. Lindsay MacDonald and Dr. Judith Meek

Student: Ashley Guilliam

Neonatal jaundice is a common condition that affects many newborn infants who have a yellowish appearance because of a high level of bilirubin in their bodies. If not detected, jaundice can cause brain damage and life-long disability. We are developing a healthcare smartphone app based on the Android platform to aid the diagnosis of neonatal jaundice. The first version of the app has already been written but requires further development to optimise the accuracy of the body colour quantification. This project will involve a) measuring the spectral sensitivity of a mobile phone, b) developing a standardised illumination lighting system, c) collecting infant data and images in the Neonatal Unit of the UCL Hospitals, and d) analysing and optimising the performance of the app. Previous programming experience is preferable but not compulsory. This project will suit a student who has interests in smartphone app development, colour science and patient contact.

Analysis of coded-aperture based x-ray phase contrast images of tumours in breast tissue

Supervisors: Prof. Alessandro Olivo and Dr. Paul Diemoz

Student: Daniel Steel

X-ray phase contrast imaging is a new imaging modality not based on x-ray attenuation, in which all details in an image are made more evident by intense edge-enhancing fringes running along their borders. This also results in making classically undetectable objects (as they oppose non absorption to x-rays) visible in the image. This method produced unprecedented results in the imaging of breast tissues, where it proved it could visualize lesions previously undetectable (or at a stage at which they are not yet detected by conventional methods). This result was obtained at synchrotrons, huge, complicated and very expensive facilities – only approximately 50 of which exist in the world. This notwithstanding, the above result was so revolutionary that it triggered the construction of the first facility for in vivo x-ray phase contrast mammography at a synchrotron in Italy, despite the very limited number of patients it can handle. More recently, the UCL team has developed a method that could make similar results achievable with conventional sources. This could make the above result widely available in hospitals and clinics across the world, allowing an earlier detection of breast tumours and consequently a reduction in the mortality rate. The team is currently using the method to image a large number of breast tissue samples containing tumours to achieve statistical significance. The student would participate in the data analysis by comparing absorption and phase contrast images of the same breast tissue sample, and quantitatively assessing the improvements brought by the latter. If time allows, synchrotron images would also be provided to allow a comparison of the UCL images against the “gold standard”. The student will gain skills in data and especially image analysis, and familiarize with some of the basic concepts of medical imaging. Basic computing skills are required.

Characterization of detector performance for x-ray phase contrast imaging

Supervisors: Dr. Marco Endrizzi and Prof. Alessandro Olivo

Student: Mebrahtu Abraham

X-ray phase contrast imaging is a new imaging modality which exploits interference and refraction effects instead of x-ray absorption. As a consequence, it has the potential to radically transform all applications of x-ray imaging (first and foremost diagnostic radiology), as it increases the visibility of all details in an image and it enables the detection of features classically considered x-ray invisible. For many years, this modality was considered to be restricted to very specialized facilities called synchrotrons, but our group has recently developed a method which makes it work with conventional x-ray sources, thus potentially enabling its clinical translation. This method however is highly affected by the performance of the used x-ray detector. Not only does this include classic parameters like noise, spatial resolution and detector response as a function of energy, but also more sophisticated and method-specific ones like signal spill-out between adjacent pixels. The student will be required to thoroughly characterize the available x-ray detectors (especially a state-of-the-art direct conversion flat panel detector based on amorphous selenium), and assess the impact of the extracted parameters on the phase contrast performance of the devices. The skills the student will gain go beyond phase contrast imaging and also cover many aspects of x-ray detector technology and characterization, which are relevant to diagnostic radiology in general.

Development of new lab set-ups for experimental x-ray phase contrast imaging

Supervisors: Prof. Alessandro Olivo and Dr. Marco Endrizzi

Student: Xiangyu Wu

X-ray phase contrast imaging has the potential to create the greatest change in the field of x-ray imaging since the invention of computed tomography. The majority of x-ray imaging systems employed in real world applications are sensitive to spatial variation of a sample's x-ray absorption characteristics. Most samples, however, also exhibit spatial variation in the way the sample retards/advances x-ray propagation, generally resulting in the refraction of x-rays. Until recently, this effect could be observed only at Synchrotrons or with specialised laboratory sources with insufficient flux to be used in most real world applications. A team within the department has, however, developed a technique capable of observing x-ray phase contrast with standard x-ray sources, called “Edge-Illumination” or “Coded Aperture” x-ray phase contrast imaging. The method has been under continuous development in the group over recent year and, recently, new modalities of implementation have been devised, which include dark-field imaging (a method sensitive to the microscopic, sub-pixel structure of the imaged sample), lab-based x-ray microscopy and others. The student will join the experimental activities of the group and study how different embodiments of the experimental apparatus affect the performance of the various imaging methods. S/he will acquire data under different experimental conditions, analyse the resulting images and draw comparison between image quality obtained from different samples, with the ultimate aim of identifying the effect that a specific experimental parameter has on the method’s performance. This will enable him/her to gain considerable skills both on the experimental and data analysis side of research in x-ray imaging. Some degree of previous experience in data acquisition and analysis would be beneficial.

Mechanical design of an optical array for a portable optical topography system

Supervisors: Dr. Nick Everdell and Dr. Danial Chitnis.

Student: Rhys Williams

The Biomedical Optics Research Laboratory (BORL) is developing a wireless and portable optical topography system. This is a device that uses near-infrared light to image the brain (for more details click here). This project involves the mechanical design of the optical array that will be applied to the scalp. We will use a design package such as Autodesk Inventor, and 3D print the prototype designs.

Comparison of different vein-viewing technologies using a computer model of light in tissue

Supervisors: Prof. Jem Hebden and Samuel Powell

Student: Dulagy Riad

Commercial “vein viewing” devices have been developed to improve the visualisation of subsurface blood vessels prior to injecting a needle to deliver a drug or extract a blood sample. These imaging devices involve illuminating the skin with near-infrared light, which provides much better contrast between blood and other tissues than visible light. Click here to view a demonstration of one example of a commercial system. The objective of this project is to use a computer simulation of light in tissue to compare the performance of different types of vein-viewing device. A so-called “Monte Carlo” model will be used, which mimics how near-infrared light is scattered and absorbed as it travels through biological tissues. Initially, the student will adapt an existing model, enabling it to simulate the specific geometries of two or more commercial systems. Then the student will employ the model to generate data which simulate measurements on real tissue. No previous experience in computing programming or modelling is required. 

Generating phantoms with optical properties matched to those of fruits

Supervisors: Prof. Jem Hebden and Dr. Adam Gibson

Student: Heidi Lui

The UCL Biomedical Optics Research Laboratory (BORL) have extensive expertise in the development of physical models of human tissue (known as “phantoms”) which have optical properties matched to those of real human organs. These are used to evaluate new optical techniques and instruments for diagnostic monitoring and imaging. It has recently been suggested that the optical techniques developed by BORL and other groups could also be used to assess the quality of fruits prior to their distribution to shops (which has a very considerable commercial potential). The objective of this project is to develop a couple of phantoms which mimic the optical properties of two different fruits. The student will initially perform a literature search on previous work in this area, and determine what is already known about the optical properties of fruits. The two phantoms will be constructed from polyester resin (plus appropriate agents to simulate scatter and absorption) and cast into the same shape as the fruit. Optical measurements performed on the phantoms will then be compared with fruit specimens.

Skin sparing in proton therapy

Supervisors: Dr Adam Gibson and Dr. Jenny Griffiths

Student: Shaun Trussell

In standard photon radiotherapy, the radiation dose gradually increases over the first centimetre or so, meaning that the dose to the skin is reduced. Protons can be used for radiotherapy instead of photons, but their behaviour at very small penetration depths is less well understood. In this project, you will create a Monte Carlo model of proton transport in tissue using GEANT4 and study the dose distribution in the skin. This will be supported by a review of the physics of proton propagation, to develop a thorough understanding of skin sparing in proton therapy and how it can be utilised in clinical practice. This project will require computer programming in C++ and some mathematics .

Experimental characterisation of laser generated ultrasound sources

Supervisors: Dr. Ben Cox and Dr. Bradley Treeby

Student: Conor Barrett Nnochiri

Conventional ultrasound sources are constructed from piezoelectric materials. These produce sound waves by exploiting the piezoelectric effect in which a large voltage applied across the element gives rise to a mechanical stress. This type of source is relatively cheap and easy to construct, and has been used with great success for many years. However, one limitation of piezoelectric sources is that they are resonant structures. This means that driving the source with a single top-hat voltage pulse will result in a short tone-burst of sound. The consequence of this is that the bandwidth (meaning the range of frequencies the source can produce) is limited to a relatively narrow frequency range around the mechanical resonant frequency of the material. In some situations, for example in tissue characterisation and ultrasound tomography, it is useful to use an ultrasound source with a much wider bandwidth. Such a source can be created using laser-generated ultrasound. This works by illuminating an optically absorbing layer with short nanosecond laser pulses. The absorption and thermalisation of the photons then produces very broadband ultrasound waves. The aim of this project is to design, construct, and test a novel experimental device that can be used to characterise different types of optically absorbing layers. The device will consist of (1) a sample holder in which microscope slides deposited with different absorbing layers can be placed, and (2) a detector holder in which a membrane hydrophone can be placed. After construction, the device will be used to measure the response of several different optical absorbers, for example, carbon-polymer composites of different types. The project will contain a large lab-based component using a range of delicate and specialised equipment (including laser sources), so much of the work will need to be completed on campus. The project would suit a motivated student with the patience and attention-to-detail required for designing and conducting experiments. Some programming in LabVIEW may also be required.

Defining ultrasound source conditions for numerical models

Supervisors: Dr. Bradley Treeby and Dr. Ben Cox

Student: Natasha Sheard

Accurately simulating how ultrasound waves propagate through the human body can be a very powerful tool. For example, simulations can be used to design new ultrasound probes, to train people to use diagnostic ultrasound machines, and to test the safety of ultrasound equipment by calculating the ultrasound dose delivered to tissue under different conditions. A key consideration is how to define the ultrasound source (i.e., how the ultrasound waves are generated or added) in the numerical model. In the model equations there are two possibilities. The first is the injection of mass or volume velocity, the second is the injection of force. The aim of this project is to determine which source type (or combination of sources) gives the most accurate representation of conventional piezoelectric ultrasound sources. This will be investigated in several stages, namely: (1) measuring the surface displacement of an ultrasound source using a laser Doppler vibrometer, (2) measuring the beam pattern produced by the same source inside a scanning tank, (3) calculating the pressure and velocity on the surface of the source using the scanning tank measurements and a holography technique, and (4) using the source distributions from steps 1 and 3 in different ways within a k-Wave model, and then comparing the modelled beam pattern with that measured in step 2. The project will contain a large lab-based component using a range of delicate and specialised equipment, so much of the work will need to be completed on campus. The project would suit a motivated student with the patience and attention-to-detail required for designing and conducting experiments. For the numerical simulations, programming in MATLAB will be required.

Deformable registration of paired breath-hold CT lung images for the assessment of the stage and severity of chronic obstructive pulmonary disease

Supervisors: Dr. Jamie McClelland and Felix Bragman

Student: (Project available)

Chronic Obstructive Pulmonary Disease (COPD) is a common disease, which has been identified as the fourth leading cause of mortality and morbidity within the USA with projected global numbers rising to the fifth and third most common cause of morbidity and mortality, respectively, by the year 2020. It is a progressive non-reversible disease, which is characterised by airflow limitation and obstruction. It is a highly complex, multi-dimensional disease consisting of three main subtypes; chronic bronchitis, chronic bronchiolitis and emphysema. Spirometry is the current accepted gold standard for the assessment and staging of COPD. However, a limitation of spirometry is that it produces a single, global measure, which ignores the complexities and the underlying spatial progression of COPD. This is motivating the use of imaging techniques and the development of novel quantitative tools for the analysis of COPD. Deformable image registration is the process of finding the transformation, which aligns two images into the same reference frame. Registration of chest images is a challenging task. This is due to the large non-linear deformation seen during the respiration process, the sliding motion of the lung with respect to the ribcage in addition to the local intensity changes resulting from to the variation of tissue density as a result of the breathing process. Registration of the lung sees various clinical applications notably in radiotherapy and more recently in the study of COPD. The main aim of this project lies in the investigation and development of state of the art techniques for achieving accurate lung registration. Work will build upon recent developments at the Centre for Medical Image Computing and will be based on the NiftyReg registration package. Various routes may be undertaken to improve the registration. This includes investigating the limits and optimal parameters of the current algorithm, employing a feature-based step to guide the deformable registration and investigating new regularisation schemes to deal with the sliding boundary conditions. This project will requires strong mathematical, computing and programming skills, in addition to a willingness to learn about registration algorithms and the underlying mathematics. This project may lead to a conference publication upon successful completion.

Canonical correlation analysis in the study of cerebral interrelations with systemic variables: application in acute brain injured patients

Supervisors: Dr. Ilias Tachtsidis and Dr. David Highton

Student: (Project available)

Brain functional near-infrared spectroscopy (or fNIRS) is a technique that uses non-invasive optical reflection measurements to monitor brain tissue haemodynamics and oxygenation by resolving the concentrations of oxygenated haemoglobin (HbO2), deoxygenated haemoglobin (HHb) and brain tissue oxygen saturation (or tissue oxygenation index (TOI)). For several years we have been using this technique to monitor brain tissue physiology and pathophysiology in acute brain injured patients in the neuro-intensive care unit. In addition to our fNIRS measurements we monitor intracranial pressure, blood pressure, arterial saturation and other systemic physiological variables. One of our main interests has been deciphering the relationship between the brain fNIRS measurements with: (1) other brain physiological measurements such as intracranial pressure and; (2) the systemic physiology such as blood pressure. The aim of this project is to use canonical correlation analysis (or CCA) to investigate the above interrelationships. CCA is a statistical method that analyzes the interrelation between variables in multi-dimensional datasets. CCA can be seen as an extension to normal correlation analysis, in which the proximity between two multidimensional datasets, instead of vectors, is analyzed by means of canonical angles. CCA determines how strongly the variables in both datasets are related. It is also possible to determine which and how many of the independent variables explain most of the variation in the dependent dataset. The student will be using a CCA toolbox that was developed in our lab with multidimensional data set that collected in the neuro-critical care unit from acute brain injured patients. The project will involve some development on the analysis methodology and will require from the student to analyse data and do some statistics. This project is mainly computational and will be suitable for a student with a general interest in monitoring brain physiology, fair knowledge of MatLab and signal processing methods.

Is functional magnetic susceptibility mapping feasible at a magnetic field strength of 3 Tesla? Assessing the importance of physiological noise correction

Supervisors: Dr. Karin Shmueli and Dr. David Thomas

Student: (Project available)

Functional Magnetic Resonance Imaging (fMRI) is widely used for studying human brain function. It relies on changes in the magnitude of the complex MRI signal but the phase of the signal has also been shown to change on brain activation. Susceptibility mapping, developed by Dr Shmueli and others, is a technique to calculate maps of the tissue magnetic susceptibility which represents the physiological changes in blood oxygenation underlying fMRI. Functional susceptibility mapping is emerging at a field-strength of 7 Tesla which gives larger signal-to-noise ratios and allows detection of small signal changes. We will investigate whether functional changes in the tissue susceptibility can be measured at 3 Tesla: the workhorse field strength for human fMRI studies. The student will analyse fMRI data acquired at 3T. Physiological noise from the heart-beat and respiration has a very large effect on functional susceptibility mapping measurements and must be removed, particularly at high magnetic field strengths. A primary focus of this project will be to implement physiological noise correction methods using measured respiratory and cardiac signals. The student will assess the effect of physiological noise correction to determine whether it needs to be applied for functional susceptibility mapping at 3 Tesla.

Evaluation of inverse source modelling of the cortical evoked response in the anaesthetised rat in comparison with Electrical Impedance Tomography of fast neural activity

Supervisors: Prof. David Holder and Dr. Kirill Aristovich.

Student: (Project available)

EIT is a novel medical imaging method, with which images of the electrical impedance of the head can be produced with a box about the size of a paperback book, laptop  and EEG electrodes on the head.  It is portable, safe, fast and inexpensive.  The supervisor’s research has been to develop its use in imaging functional activity in the brain. It could be used for imaging fast neural activity over milliseconds, which would constitute a major advance in neuroscience methods. Research into this is currently being undertaken in the anesthetized rat. The brain is exposed and recording is undertaken during repeated physiological stimulation of the sensory or visual systems. Recording is undertaken with a probe of 32 cortical electrodes about 6 mm square. EIT data is recorded at the same time as the brain’s own response as well as other data such as intrinsic optical imaging. Inverse source modelling of the EEG is a method in which the origin of electrical signals is calculated from boundary voltage signals – in this case, the evoked response signals recorded from the epicortical electrode array. In this project, inverse source modelling software from the SPM suite developed at UCL will be adapted for use with the EIT rat data. The results of source modelling will be compared with EIT data. Skills to be acquired: programming in Matlab, learning SPM, signal processing, and data analysis. All data will be provided by medical researchers. The project is suitable for a student with a background in physics, engineering or computing, or a medical student with computing experience and an interest in programming.

Real-time implementation of an algorithm for removing artefact from the EEG in Electrical Impedance Tomography (EIT) of epileptic activity

Supervisors: Prof. David Holder and Dr. Gustavo Santos

Student: (Project available)

EIT is a novel medical imaging method, with which images of the electrical impedance of the head can be produced with a box about the size of a paperback book, laptop  and EEG electrodes on the head.  It is portable, safe, fast and inexpensive.  The supervisor’s research has been to develop its use in imaging functional activity in the brain. One exciting application lies in its use to image changes in the brain due to epileptic activity. In epilepsy, abnormal activity may occur in the form of seizures in which there is continuous abnormal activity lasting a minute or so.  EIT could be used to provide a uniquely new method for imaging brain activity in such seizures which could be used in surgery for epilepsy. In order for this be realised, EIT needs to be recorded at the same time as EEG over several days in patients on a ward who have been specially brought in for observation. Both are recorded with about 20 electrodes glued to the scalp. Unfortunately, the EIT injects an artefact into the EEG signal. A method for removing this has been developed but it currently takes several minutes of post-processing off-line after the EEG has been acquired. As some clinicians need to see real-time EEG at the bedside as it is collected, it is desirable to run the cleaning algorithm in real time. The purpose of the project will be to implement and test real-time implementation of the algorithm. Initially, the student will read relevant background literature and become familiar with the algorithm. They will then develop a way to run it in real time, initially on a PC running in parallel with commercial EEG software. If this is not sufficiently fast, then other methods to speed up processing will be investigated, such as the use of a parallel Graphical Processing Unit added to the PC. Skills to be acquired : programming in Matlab, C or C++, signal processing, and biomedical instrumentation. The project is suitable for a student with a background in physics, engineering or computing, or a medical student with experience and an interest in programming.

Electrical Impedance Tomography (EIT) of evoked physiological activity

Supervisors: Prof. David Holder and Dr. Kirill Aristovich

Student: (Project available)

EIT is a novel medical imaging method, with which images of the electrical impedance of the head can be produced with a box about the size of a paperback book, laptop  and EEG electrodes on the head.  It is portable, safe, fast and inexpensive.  The supervisor’s research has been to develop its use in imaging functional activity in the brain. One possible use could be to image increases in blood volume which occur over some tens of seconds during normal brain activity, such as during the standard clinical techniques of stimulation of the visual system by flashing lights or the somatosensory system by mild electrical stimulation at the wrist. Such imaging can already be performed by fMRI (functional MRI); the advantages of EIT are that similar images could be acquired with portable much less expensive  technology which would increase its availability. EIT data has been collected in these situations before and led to a landmark publication in which reliable single channel data were observed but, unfortunately, the data was too noisy to form into reliable images. Since then, the electronics and imaging software have been improved – for example, we can now collect images at multiple frequencies whereas before they were only collected at one. This gives greater opportunities to reduce noise. To start with, the student or a team of students will evaluate two new EIT imaging systems, the Kyung Hee Mk 2.5 and the Swisstom, in a saline filled tank and compare their performance with an older UCLH EIT system. If time permits, then students will work together to collect EIT data during repeated evoked activity in about 10 healthy volunteers, and then will help produce images using Matlab code written for this purpose. Digital photos will be taken around the head, and then photogrammetric software will be used to localise their positions. Images will be reconstructed using an MRI of the patient’s head, which needs to be converted to a Finite Element model with software for segmenting medical images and meshing them. The accuracy of these images will be compared with similar studies using fMRI. Skills to be acquired: Students will spend time in the lab in Medical Physics at UCL learning relevant methods and analysing the data, and some time in Prof Holder’s department at UCH, learning how to collect evoked responses using scalp electrodes. Skills to be acquired will include one or more of: medical image reconstruction; photogrammetric software use; medical image segmentation and meshing software; EEG electrode placement and use; experimental design and data analysis. The project would be suitable for a single student or a team of 2 or 3, with backgrounds in physics, engineering, computing, or medicine.

Exploring the limits of the quantitative retrieval of x-ray phase

Supervisors: Dr. Paul Diemoz and Prof. Alessandro Olivo

Student: (Project available)

X-ray phase-contrast imaging (XPCi) allows the generation of images with highly improved contrast compared to conventional X-ray imaging techniques. While the latter are based on measuring the attenuation of a photon beam when passing through different parts of the sample, XPCi exploits the interference/refraction effects experienced by the photons. Until recently, XPCi has been mostly limited to specialized and expensive synchrotron facilities, due to the need of using photon beams of very high coherence and flux. Our group, however, developed a new implementation of XPCi, the “coded apertures” (CA) technique, which was proven to work efficiently even with standard x-ray sources and laboratory equipment. It has therefore great potential for applications in many fields of x-ray investigation, such as materials science, biomedical and clinical imaging. Recently, we have developed an algorithm to extract quantitative sample information from experimental CA XPCi images. This algorithm is, however, based on some simplifying assumptions that are likely to not be valid for all samples and experimental conditions that could be encountered in practice. This project will consist in studying how the method’s accuracy varies for different sets of experimental parameters and different types of samples. To this aim, the student will make use of a simulation code developed within our group, and use it to test the quantitative values provided by the algorithm against theoretically predicted ones. The ultimate goal of this study is to find some simple rules that describe which parameters are the most important in determining the method’s quantitative accuracy and under which experimental conditions the algorithms provides satisfying results. The student will gain skills in simulation methods, data analysis, and familiarize with the basic concepts of optics. A solid physics background is required.

Radioisotope mapping using RadICAL

Supervisors: Prof. Robert Speller and George Randall

Student: (Project available)

RadICAL is a detector system designed for localising radioactive isotopes. Several versions have been designed and built and this project is to carry out a series of experiments to evaluate their performance. It is hoped that two types of experiments will be carried out. Firstly a set of experiments designed to measure parameters such as detection efficiency, spatial resolution, repeatability, linearity, etc. These should enable selection of operating parameters that will optimise the performance for different tasks. The second set of experiments will try to simulate a range of different tasks. The project is mainly experimental but will involve some computing for analysing the results.

Monte Carlo modelling of X-ray diffraction

Supervisors: Prof. Robert Speller and Nick Calvert

Student: (Project available)

Tissue diffraction using X-rays can potentially play an important role in the diagnosis of disease. We are currently studying how this technique can best be applied in the detection of early breast cancer. However, to support our experimental studies we are developing modelling techniques. This project is to look at using GEANT4 (a Monte Carlo based programme) to include diffraction data on tissues. It requires an interest and some experience in computing. The eventual aim will be to see if we can reproduce our experimental results.

Modelling patient throughput in a radiotherapy department

Supervisors: Dr. Adam Gibson and Dr Andy Chow

Student: (Project available)

The radiotherapy department in a hospital is busy, with patients moving from room to room for different scans and tests, and returning for repeated treatment fractions. In this project, you will develop a computer model of patient flow through the department, which will allow us to predict the impact of changes to working practise on the efficiency of the department. The project will involve writing and developing a computer model,  testing it against measured patient throughput and using it to predict the effect of new working practises.

Artefact rejection in x-ray CT imaging

Supervisors: Dr Adam Gibson and Dr Jenny Griffiths

Student: (Project available)

Small, dense areas in CT images such as fillings or metal implants cause significant errors in the reconstructed image. CT images are used to plan radiotherapy treatments, but if the patient has a metal implant near the area being treated, the artefact in the image can lead to significant errors. You will write a computer program to reconstruct CT image and investigate ways to improve the image reconstruction to make it more tolerant of metal implants. This project will require mathematics and computer programming.

Automated neonatal monitoring

Supervisors: Dr. Adam Gibson and Dr Topun Austin

Student: (Project available)

We have recorded about 2 weeks of multichannel monitoring data on 9 babies in intensive case. We have already showed that intelligent analysis of this data can identify adverse events. In this project, you wll carry out further analysis, to determine the analysis technique which maximises the sensitivity and specificity with which the system can identify adverse events. This project will require mathematics and computer programming.

Acoustic emissions from a proton beam

Supervisors: Dr Adam Gibson and Dr Ben Cox

Student: (Project available)

We have a well-established research group in the area of photoacoustics. When tissue is illuminated with near infrared light, the blood vessels absorb energy, heat and expand, producing an acoustic wave which can be measured at the surface. In this project, you will investigate the extension of photoacoustics to detecting acoustic emissions from a proton beam in tissue. When protons are used for radiotherapy, energy is deposited in tissue and there is some evidence that acoustic waves can be generated. You will use existing software to determine the dose deposition from a proton beam, and then use that in a computer model of acoustic propagation to investigate the signal size for a range of different conditions. The outcome will be a recommendation as to whether this method could be used clinically. This project will require some mathematics and computer programming.

Measuring the directivity of ultrasound detectors

Supervisors: Dr. Ben Cox and Dr. Bradley Treeby

Student: (Project available)

Diagnostic ultrasound imaging, ultrasound computed tomography, and photoacoustic tomography all rely on the use of ultrasound detectors to record ultrasound waves. The recorded signals are then used in various ways to reconstruct images. In most cases, the detectors are assumed to act like infinitesimal point receivers that are equally sensitive to ultrasound waves from all directions. However, in practice, ultrasound detectors have a finite size, and the sensitivity varies with the angle of the incoming wave relative to the transducer surface (this variation is known as the directivity of the transducer). Accurately measuring this directivity as a function of frequency is important for understanding and improving the quality of ultrasound images. However, it is also a very challenging task. This is because it is difficult to generate and align plane waves at precise angles relative to the ultrasound detector. The aim of this project is to design, build, and test a novel experimental device that can measure the directivity of ultrasound detectors. This will be based on the use of a laser-generated plane wave ultrasound source which exploits the photoacoustic effect to generate sound. The device will be automated using custom software written in LabVIEW. Design parameters such as the source size and the source-receiver distance will be evaluated using the k-Wave Acoustics Toolbox. After the device is constructed, the directivity of a range of different ultrasound detectors will be assessed, including membrane, needle, and fibre optic hydrophones, and conventional PZT ultrasound transducers. Depending on progress, the incorporation of detector directivity into common image reconstruction algorithms will also be explored. The project will contain a large lab-based component using a range of delicate and specialised equipment (including laser sources), so much of the work will need to be completed on campus. The project would suit a motivated student with the patience and attention-to-detail required for designing and conducting experiments. Some programming in LabVIEW may also be required.

Measurement and modelling of reflection and transmission coefficients for focused ultrasound beams

Supervisors: Dr. Ben Cox and Dr. Bradley Treeby

Student: (Project available)

Accurately simulating how ultrasound waves propagate through the human body can be a very powerful tool. For example, simulations can be used to design new ultrasound probes, to train people to use diagnostic ultrasound machines, and to test the safety of ultrasound equipment by calculating the ultrasound dose delivered to tissue under different conditions. An important consideration for ultrasound models is how to accurately account for changes in the material properties within tissue (for example the sound speed and density). A step-change in the material properties between two different tissue types will cause the reflection and refraction of the incoming ultrasound waves. For a plane wave and a flat interface, these effects can be predicted using Snell’s law. However, in tissue, the situation is much more complex. This project will combine experimental measurements and numerical simulations to study the reflection and transmission of ultrasound beams by different interfaces encountered in the body. The aim will be to experimentally validate the ability of the k-Wave Acoustics Toolbox to model sound waves in heterogeneous media. The first goal will be to setup an experiment in a motorised scanning tank to measure the transmitted and reflected ultrasound fields using different ultrasound sources. The same scenario will then be modelled using the k-Wave Toolbox (in MATLAB) and the results compared. The second goal will be to consider a range of different interfaces (flat, curved, etc) with different percentage changes in material properties. The project will contain a large lab-based component using a range of delicate and specialised equipment, so much of the work will need to be completed on campus. The project would suit a motivated student with the patience and attention-to-detail required for designing and conducting experiments. For the numerical simulations, programming in MATLAB will be required.

Time-reversal focusing for high-intensity focused ultrasound treatments in the brain

Supervisors: Dr. Bradley Treeby and Dr. Ben Cox

Student: (Project available)

High-intensity focussed ultrasound (HIFU) is a therapeutic application of ultrasound in which a high-powered ultrasound beam is tightly focussed on a particular target within the body. The absorption of ultrasound in the target region gradually causes the tissue to heat up, which leads to tissue necrosis (cell death). In recent years, HIFU has been trialled clinically to treat a number of disorders in the brain, including tumours, thrombolytic strokes, and essential tremor. These treatments require very high precision due to the critical importance of leaving healthy brain tissue unharmed. However, the skull causes significant distortion to shape and position of the ultrasound beam. The aim of this project is to use numerical modelling to specify the how the HIFU source (which may contain between 256 to 2048 individual ultrasound elements) should be controlled so that this distortion is corrected. An x-ray CT image of the patient’s skull and brain will be used to define the material properties within the acoustic model. Simulations will then be performed using an ultrasound source placed at the target region within the brain. The ultrasound waves reaching the HIFU source will be recorded and later reversed to allow the ultrasound beam from the HIFU source to refocus on the target region. The effect of source sizes and numbers of elements on the precision of performing HIFU in the brain will then be investigated. This project will contain a large computational component, including using high-performance computer facilities. Programming in MATLAB will also be required.

Simulation of dynamic diagnostic ultrasound images

Supervisors: Dr. Bradley Treeby and Dr. Ben Cox

Student: (Project available)

Ultrasound imaging is an important medical imaging technique based on the propagation of acoustic waves through biological tissue. A diagnostic ultrasound scanner produces an image by sweeping an ultrasound beam back and forth through tissue and measuring the sound that is reflected from different tissue interfaces inside the body. The simulation of this process (i.e., the simulation of ultrasound images) is very powerful tool for a number of applications, including medical image registration, and training people to recognise different diseases on ultrasound images. However, most existing methods make unrealistic assumptions about the physics of sound propagation in tissue. The aim of this project is to produce accurate simulations of dynamic ultrasound images using the k-Wave Acoustics Toolbox. This will involve several stages, including: (1) defining a numerical tissue phantom, for example, of the carotid artery, (2) deforming this phantom according to the cardiac cycle, and (3) using the k-Wave toolbox to define the properties of a diagnostic ultrasound probe and then simulate the ultrasound images. Depending on progress, the second part of the project will be to investigate how the small-scale heterogeneities in tissue (which lead to the speckle pattern in ultrasound images) should be defined. The project would suit an ambitious and motivated student who is interested in simulation and modelling and wants to contribute to the current state-of-the-art in ultrasound. This project will contain a large computational component, including using high-performance computer facilities. Programming in MATLAB will also be required.