MPHY3000/MPHYM000: Medical Physics Projects 2011/12

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 17, 2011. Your supervisor must also complete a Project Risk Assessment Form. Students are required to hand in the form with 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 16, 2012.
  • Project talks will be held on Wednesday March 14, 2012 in Room 2.14 of the Malet Place Engineering Building.
  • Final Reports are due by Friday March 23, 2012. Please hand in to the Medical Physics Departmental Office (second floor of the Malet Place Engineering Building).

Project information

Validation of a wireless NIRS system

Supervisors: Dr. Nick Everdell and Dr. Christina Kolyva

Student: Maciej Grzesiak

Near-infrared Spectroscopy (NIRS) is an optical technique that uses harmless near-infrared light to monitor tissue oxygenation; NIR light can penetrate tissue and therefore, solely on the basis of the NIR light we shine and the light that is reflected back, we can work out the concentration of the major light absorbers present in the tissue, such as oxy- and deoxy-haemoglobin. Because of its non-invasive character NIRS has attracted the interest of Sports Science, for monitoring in real-time muscle oxygenation in athletes during training. We have developed a wearable, wireless-enabled NIRS device for this purpose which, at the current stage, we would like to validate against another widely-recognised benchtop NIRS device. The focus of this project will be to design the experimental protocol, recruit healthy volunteers and collect data with both devices during simple (static) challenges that change muscle and/or brain oxygenation levels. Experiments will be conducted in our lab at Medical Physics. The project would be suitable for a student with an interest in human physiology and will involve data collection and processing.

Tracking proton trajectories for proton radiography

Supervisors: Prof. Gary Royle and Edgar Gelover Reyes

Student: Emma Wroe

The aim of this project is to improve the quality of proton radiography images. Protons follow a curved trajectory through tissue so a two dimensional detector does not provide enough information to construct a useful image of a patient. The project will look at using a number of detection layers so that the trajectories of protons through a patient may be reconstructed.

Intelligent CT

Supervisors: Prof. Robert Speller and Dr. Peter Munro

Student: Anik Ghai

X-ray and gamma ray imaging are still the most frequently carried out examinations despite the concern for radiation burden. Recently the UCL Radiation Physics Group developed a technique capable of reducing dose without a loss of image quality – the technique is called I-ImaS. This technique adjust the imaging conditions on-the-fly to suit each local region in the object being imaged. The technique was designed for planar imaging but now we wish to extend this to CT.
A project to investigate the I-ImaS_CT concept. Last year a student demonstrated that the concept is viable for dose reduction but did not really study the steering algorithm that should be used to control exposure. Furthermore only one type of imaging task was studied. The project requires phantoms to be built, software to be written and many experiments carried out using the X-Tek CT system. This is an u/g merging into an MSc project.

RadiCal

Supervisors: Prof. Robert Speller and George Randall

Student: Claire Lillington

Many monitoring devices of radioactivity exist but none can identify the direction in which the radiation source exists without the use of a collimator. Recently a new device has been suggested to overcome this problem – the RadICal detector.
The RadiCal concept could be tested both experimentally and by the use of modelling techniques. The route that will be taken will depend upon the student’s interests. Experimental work will be undertaken with existing equipment and modelling can be adapted from existing codes. The project will to test the feasibility of the concept and attempt to optimise the design for different applications.

Development of breast density measurement technique for cancer screening

Supervisors: Prof. Robert Speller and Dr. Caroline Reid

Student: Ben Hardy

Recent studies have shown that the radiographic density of breast tissue is linked to a woman possibly developing breast cancer in the future. However, to measure the radiographic density requires a mammogram being taken. For screening the population it would be much better to use alternative techniques. This project is to look towards a method to obtain the same, or related information, without the use of ionising radiation. Radiographic density can be related to physical density (under certain assumptions) and hence to estimate radiographic density in vivo requires a method for estimating the physical density of breast tissue in-vivo. During this project different techniques will be considered for estimating both the volume and mass but, for practical experiments, all of them require a phantom to be built of materials that are mechanically, radiographically and physically tissue equivalent. Therefore, the first task will be to build different phantoms and then develop techniques for estimating their density under ‘in-vivo’ conditions. The work will require a student interested in a project requiring practical skills and it is likely that the project may take different directions during the development stages of the phantom. The project is equally suited to undergraduate and MSc students.

Multispectral imaging for improved quatification

Supervisors: Prof. Robert Speller and Dr. Caroline Reid

Student: (Project available).

Conventional X-ray imaging is carried out without knowledge of the spectral changes introduced when the beam traverses the object. Thus the only parameter that can be used to infer the types of tissue imaged is the reduction in the total intensity. However, if changes in the spectral components removed from the beam can be determined then chemical composition can be determined. This project will investigate this proposal using a scanned CZT sensor to simulate an imaging detector. The project will involve experimental activities combined with some computing.

Computational modelling of pH dynamics during brain tissue anoxia and ischaemia

Supervisors: Dr Ilias Tachtsidis and Ms Tracy Moroz

Student: (Project available)

In our pursuit to understand the brain tissue physiology, metabolism and regulation we have adopted a “systems biology” approach and developed a computational model (BRAINCIRC) which we recently extended to include the neonatal brain physiology and metabolism (BabyBrain model). Intracellular pH varies as a function of flow, energy stores and oxygenation. Low pH can be a precursor of apoptosis and cell death. Thus, the characterization of pH dynamics may have predictive value for cell death for example in perinatal cerebral hypoxic-ischemia (HI) following birth asphyxiation, in traumatic brain injury and stroke. As part of this project the student will run simulations with our models to investigate the pH dynamics in the models and progress to suggest and develop possible submodels that describe the brain tissue pH dynamics. The ultimate aim will be to use this extended model to extract additional clinically useful information about pH brain regulation. This project would be suitable for students with an interest in brain tissue physiology/biochemistry and will involve data processing and some statistical analysis.

Explore the optical measurements of brain tissue oxygenation and haemodynamics during a hypoxic ischaemic insult

Supervisors: Dr Ilias Tachtsidis and Dr Stuart Faulkner

Student: (Project available)

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 neonatal encephalopathy secondary to birth asphyxia. The Perinatal-Brain Magnetic-Resonance Group at UCLH has a well established programme of research characterising and monitoring neonatal brain injury. Recently as part of collaboration with the Biomedical Optics Research Lab (BORL) they have been measuring brain tissue oxygenation and haemodynamics in a brain injury animal model using an in-house developed near-infrared spectrometer. The main focus for this project will be the data analysis of physiological signals obtained before, during and after brain injury. The student will use novel software tools that will allow quantification of the near-infrared measurements and then will focus on analysing those in conjunction with systemic signals and possible magnetic resonance spectroscopy measurements. The larger scope of the analysis is to investigate the biophysical and biochemical changes that happen in birth asphyxiated infants. This project would be suitable for a student with an interest in physiology/pathophysiology, brain tissue biochemistry; and will involve data processing and statistical analysis.

Monitoring of High Intensity Focused Ultrasound treatment with acousto-optics

Supervisors: Dr Terence Leung and Dr Dean Barratt

Student: Ranjit Atwal

High Intensity Focused Ultrasound (HIFU) is a minimally invasive therapeutic technique which exploits focused ultrasound to heat up and destroy tumour remotely. We are currently developing a technique known as Acousto-Optics to monitor the treatment zone by detecting changes in colour and texture. In this technique, near infrared light is used to illuminate the tumour and surrounding tissues. Light that passes through the treatment zone where HIFU is targeted will be modulated because HIFU introduces particle displacements and changes in optical refractive index. By measuring the diffused modulated light, information about the colour and texture of the tumour, which will change during the course of HIFU treatment, can be derived. This project involves (1) the operation of a clinical ultrasound system, and (2) performing AO measurements on the biological samples. This project is best suited to a student who likes ultrasound technology and enjoys performing scientific measurements.

Clinical monitoring with near infrared light, ultrasound and microbubbles

Supervisors: Dr Terence Leung and Jack Honeysett

Student: John Hall

Microbubbles are gas-filled tiny bubbles with a diameter of a few microns. They are strong ultrasound wave reflectors and are therefore routinely used as contrast agents in enhancing the quality of medical ultrasound images. We have been investigating the optical properties of microbubbles in blood which can potentially be exploited to measure blood oxygenation non-invasively in the heart. One crucial part of this research is to be able to quantify the concentration of microbubbles in blood. The aim of this project is to develop a technique to measure the concentration of microbubbles and the amount of light that they scatter with and without the ultrasound. This project will suit a student who enjoys building models and performing scientific measurements. 

Artefact rejection in x-ray CT imaging

Supervisors: Dr Adam Gibson and Dr Gary Royle

Student: Minal Modi

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 some mathematics and computer programming.

Motion detection and analysis during seizure

Supervisors: Dr Adam Gibson and Dr Nick Everdell

Student: Jonathan Mayhew

It can be difficult to determine whether a seizure is epileptic in origin or not. It has been proposed that the appearance of movement during the seizure may help to distinguish between epileptic and non-epileptic seizures. In this project, you will build an accelerometer which can be placed on the arm during seizure and record arm movement. You will then analyse this arm movement to distinguish between different types of motion.

Modelling patient throughput in a radiotherapy department

Supervisors: Dr Adam Gibson and Dr Gary Royle

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.

A study of fluid distribution in absorbent materials using microCT

Supervisors: Prof Alan Cottenden and Dr Gary Royle

Student: (Project available)

MicroCT is a variant on x-ray computer tomography in which three-dimensional images of small volume samples can be produced with high spatial resolution. This project will involve investigating the potential of microCT for measuring the distribution of water in absorbent materials of the kinds used in medical products such as incontinence pads and wound dressings. The hope is that the technology will provide new insights into material / fluid interactions which will ultimately lead to more effective products.

How much spilled coffee can you mop from a carpet using a kitchen towel?

Supervisors: Prof Alan Cottenden and Mihaela Soric

Student: (Project available)

Theory says that partitioning of fluid between two porous absorbent materials in contact with each other depends on how their capillary pressures vary with their saturation (how wet they are): fluid flows until their capillary pressures are equal. This is what determines how much spilled coffee you can mop from a carpet with a kitchen towel and – more important, medically - the partitioning and distribution of liquid between the different layers in products such as incontinence pads and wound dressings, which is important in drawing and storing fluid away from the skin. This project will involve using a porosimeter to measure the capillary pressure as a function of saturation of a range of fabrics; using the porosimetry data for pairs of fabrics to predict how fluid will distribute between them; and running experiments – such as blotting water from carpet samples – to determine how well the theory predicts the reality. Interestingly, theory predicts that the equilibrium distribution of fluid between two fabrics depends on which one starts out the wettest. The project will be primarily experimental and will be based at the UCL Archway campus (by Archway tube station).

Predicting the absorption capacity of absorbent materials as a function of pressure

Supervisors: Prof Alan Cottenden and Mihaela Soric

Student: (Project available)

Conventionally, the absorption capacity of the porous absorbent fabrics that are widely used in such medical products as incontinence pads and wound dressings is measured by pouring water into samples held under load until saturation is reached. This is laborious and yields results only for the specific pressures selected. The project will involve investigating a potentially better approach. In such fabrics, the fluid is held between the fibres and so absorption capacity is determined by the void volume fraction of the fabric. For a give fabric this, in turn, depends on how compressed the structure is which, in turn, depends on the applied pressure. The plan is to use Archimedes principle to determine the fibre volume fraction of some example materials, and compression tensometry to measure fabric thickness as a function of pressure. These data will be combined to predict the absorption capacity of the fabrics as a function of pressure, and the prediction checked experimentally against the conventional method for example pressures. The project will be primarily experimental and will be based at the UCL Archway campus (by Archway tube station).

Predicting the retention capacity of absorbent materials using porosimetry

Supervisors: Prof Alan Cottenden and Mihaela Soric

Student: (Project available)

One of the key factors determining the efficacy of the absorbent materials used in medical products such as wound dressing and incontinence pads is their ability to retain fluid against the pull of gravity. The most direct way of doing this is to measure the equilibrium saturation profile in an initially fully saturated vertical strip of fabric, once the excess fluid has drained under gravity. However, this is a laborious and time-consuming measurement to make. Theoretically, the same distribution could be generated by measuring the capillary pressure of the fabric as a function of saturation using retreating porosimetry. This project will involve validating theory against experiment for some example materials. The project will be primarily experimental and will be based at the UCL Archway campus (by Archway tube station).

Categorising and characterising populations of incontinence pad users by leakage volumes

Supervisors: Prof Alan Cottenden and Margaret Macaulay

Student: (Project available)

Although it is known that incontinent people vary enormously in the volumes of urine which they leak little is known about the range of leakage volumes for an individual and there has been little attempt to characterise and classify the incontinent population by urine loss volumes. Such knowledge would be valuable both for determining the most appropriate absorbency level pad for an individual and also in helping companies seeking to develop improved products. This project will involve data mining several large existing data sets from clinical studies (each comprising around 10,000 pad weights from around 100 subjects) to identify suitable criteria for categorising and characterising the different subsets of pad users. This project would be suitable for an intercalated student and should yield a publishable paper. The supervisors for the project are based at the UCL Archway campus (by Archway tube station).

Using infrared light to investigation the absorption properties of nonwoven felts used in medical applications

Supervisors: Prof. Alan Cottenden and Prof. Jem Hebden

Student: (Project available)

Absorbent nonwoven felts are used in a number of medical applications, notably incontinence pads and wound dressings. It is a major objective of the Continence and Skin Technology Group to establish a better understanding of how fluids interact with absorbent materials and build mathematical models which will enable the development of more effective medical products. This project will use an infrared device to investigate the absorption properties of nonwoven felts by mapping the distribution of fluid in them under a number of equilibrium (e.g. retention under gravity) and dynamic (e.g. horizontal and vertical wicking) experimental configurations. Data from the new device will be compared with both experimental data using other techniques and predictions based on existing mathematical models. The project will be primarily experimental and based at the UCL Archway campus (by Archway tube station).

Simulating the optical absorption of blood using mixtures of coloured inks in water

Supervisors: Prof. Jem Hebden and Dr. Marta Varela

Student: Priya Hunjan

Measurements of the transmission of light across tissue can be used to determine localised changes in the concentration and oxygenation of blood. Testing and validation of such diagnostic techniques in the laboratory often requires materials which can simulate the optical properties of biological tissues. The purpose of this project is to determine if a suitable combination of transparent inks of (at least six) different colours can mimic the absorption of oxygenated and deoxygenated blood over a broad range of optical wavelengths. The student will first use a spectrometer to determine the precise absorbing characteristics of each ink. A mathematical algorithm will then be developed to determine the concentrations of each ink needed to produce aqueous fluids with absorption spectra as close as possible to blood over a selected range of wavelengths. The predictions of the algorithm will then be tested experimentally. The project is suitable for any student (including intercalated students) willing to learn a little mathematics and how to use Matlab.

A feasibility study for a very low cost optical topography system using just LEDs

Supervisors: Dr. Nick Everdell and Dr. Salavat Magazov

Student: Emily van Blankenstein

An LED (light emitting diode) can also be used as a light detector (Stojanovic et al., Physiological Measurement 2007). With this in mind this project will investigate the feasibility of building a very simple, low cost optical topography system that uses LEDs as both sources and detectors. This project would suit someone with an interest in electronics and will involve some circuit design and construction. Further details of our optical topography work can be found at: www.medphys.ucl.ac.uk/research/borl/research/topography.

Design of an adaptable array for optical topography and tomography

Supervisors: Dr. Nick Everdell and Prof. Jem Hebden

Student: Barnaby Patterson

Diffuse optical imaging requires the placing of an array of optical fibres over the surface of the tissue to be imaged: www.ucl.ac.uk/medphys/research/borl/imaging. The fibres need to be held firmly in place at the surface, either in contact with or just above the tissue. They also need to be distributed evenly over the surface of the object. We have several designs for arrays already, but none of them allow the separation between optical fibres to be adjusted easily. This is important as different subjects require different optical fibre geometries. This project would involve designing and building a new type of array, one whose geometry could be easily altered and adapted to the imaging task at hand. This project would be suitable for someone with an interest in mechanical design.

Contrast and signal-to-noise ratio in x-ray phase contrast imaging

Supervisors: Dr. Alessandro Olivo and Dr. Konstantin Ignatyev

Student: Mathew Elameer

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. The classic way of classifying detail visibility in an x-ray image is based on the concepts of contrast and signal-to-noise ratio (SNR). These quantities are somewhat based on the typical characteristics of a conventional, absorption-based x-ray image, in which the part of the image occupied by the detail of interest presents a lower or higher intensity with respect to the background. The different nature of phase contrast images requires a critical revision of these classic quantities. The student will be provided with a number of images of the same samples taken with absorption and phase contrast methods. He/she will investigate ways of improve/update the definitions of contrast and SNR in order to make them suitable to this new imaging modality. The ultimate aim will be to carry out a quantitative comparison between image quality provided by conventional absorption and phase contrast methods. The student will gain skills in data analysis, image analysis and familiarize with some of the basic concepts of medical imaging. Basic computing skills are required.

e-Learning in Medical Physics and Bioengineering

Supervisors: Dr. Adrien Desjardins and Prof. Alan Cottenden

Student: Imogen House

In recent years there has been a proliferation of new learning materials and methods. Anecdotal evidence suggests that students and staff are increasingly turning to new digital media such as online videos, electronic books, and collaborative encyclopaedias to learn new topics. However, very little quantitative data is available to describe these trends. This project will involve an analysis of the materials and methods that students in our Department are currently using to learn  medical physics and bioengineering. An important outcome of the project will be a set of recommendations for optimising the learning environment in our Department.

Rotating torquemeter

Supervisors: Prof. Nick Donaldson and Tim Perkins

Student: (Project available)

An exercise ergometer has been designed and the prototype made in the Implanted Devices Group. However these machines need to be calibrated so that we can measure the power consumed versus speed and brake setting. The calibrator needs a transducer that covers an appropriate range to measure the torque in a rotating shaft. The student will design an induction device that transmits power to the transducer and sends the torque signal back while it is rotating. The system must be built and tested.

Clinical impedance meter

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: Nikhil Patel

During surgical implantation of devices, it is often necessary to measure the impedance of electrodes; conventionally this is done at 1 kHz. Remarkably, no simple hand-held impedance meter is available. This project is to design and test such a meter on the bench, then to design an appropriate printed circuit board and enclosure so that the instrument can be used in labs and operating theatres.

Portable impedance analyzer

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: (Project available)

A device that measures the impedance between two terminals across a range of frequency is useful in many fields. We are particularly interested in electrodes and therefore the impedance between pairs of electrodes in electrolyte or in the body. Analog Devices have developed an integrated circuit for this function which can interface to a PC via an USB port. The project is to develop a portable impedance analyzer for use in the lab and during operations. The hardware will be developed and a program must be written for the PC to give useful displays. Topics: impedance, impedance spectra, PC programming, USB.

History of Electrotherapy

Supervisors: Dr. Anne Vanhoest and Prof. Nick Donaldson

Student: (Project available)

Electrotherapy (medical application of electricity to the body) started in the 1740s and for 2 centuries it was offered as a treatment of many illnesses. However, by the 1970s, the methods had been abandoned yet, nowadays, the treatment of motor disorders by exploiting neural plasticity with electrical or magnetic stimulation is a hot research topic: we may wonder whether some methods that were in use for some 200 years will be rediscovered but now with some scientific understanding of the therapeutic mechanisms. Although this is a literature based project (using the Wellcome Library of the History of Medicine as well as UCL's own resources). The student should aim to critically appraise the treatments used, at least concerning the physics involved (but not necessarily the neurophysiology). Topics: biophysics, history of physics and physiology, nerve stimulation, plasticity of CNS.

Diagnosing muscle disease with Electrical Impedance Spectroscopy

SupervisorsProf. David Holder and Hwan Koo

Student: (Project available)

At present, electrophysiological diagnosis of different muscle diseases inundertaken with needle recording of the electrophysiological signals - thisis termed "Electromyography" (EMG). The idea behind this project is to makerecordings of electrical impedance to aid in this diagnosis using anElectrical Impedance Spectroscopy (EIS) system. This comprises a circularprobe about 10 cm in diameter placed on the skin which makes multipleimpedance measurements in a few seconds. The work will be to review relevantliterature concerning muscle impedance studies, and test and calibrate theEIS system in the laboratory for this purpose. If successful, this will thenbe tested in a small number of patients and normal subjects with muscledisease in Prof. Holder's clinic at UCH. Students will spend time in the labin Medical Physics at UCL learning relevant methods and analysing the data,and some time in Prof Holder's department at UCH, acquiring muscle impedancedata. Skills to be acquired will include one or more of: biomedicalinstrument use and assessment, biophysical modelling. experimental designand data analysis. The project would be suitable for a single student ormore than one working in a team, with a background in medical physics,engineering, or medicine.

Electrical Impedance Tomography (EIT) of evoked physiological activity

SupervisorsProf. David Holder and Gustavo Santos

Student: (Project available)

EIT is a novel medical imaging method, with which images of the electricalimpedance of the head can be produced with a box about the size of apaperback book, laptop  and EEG electrodes on the head.  It is portable,safe, fast and inexpensive.  The supervisor's research has been to developits use in imaging functional activity in the brain. One possible use couldbe to image increases in blood volume which occur over some tens of secondsduring normal brain activity, such as during the standard clinicaltechniques of stimulation of the visual system by flashing lights or thesomatosensory system by mild electrical stimulation at the wrist. Suchimaging can already be performed by fMRI (functional MRI); the advantages ofEIT are that similar images could be acquired with portable much lessexpensive  technology which would increase its availability. EIT data hasbeen collected in these situations before and led to a landmark publicationin which reliable single channel data were observed but, unfortunately, thedata was too noisy to form into reliable images. Since then, the electronicsand imaging software have been improved - for example, we can now collectimages at multiple frequencies whereas before they were only collected atone. This gives greater opportunities to reduce noise. Students will worktogether to collect EIT data during repeated evoked activity in about 10healthy volunteers, and then will help produce images using Matlab codewritten for this purpose. Digital photos will be taken around the head, andthen photogrammetric software will be used to localise their positions.Images will be reconstructed using an MRI of the patient's head, which needsto be converted to a Finite Element model with software for segmentingmedical images and meshing them. The accuracy of these images will becompared with similar studies using fMRI. Skills to be acquired: Studentswill spend time in the lab in Medical Physics at UCL learning relevantmethods and analysing the data, and some time in Prof Holder's department atUCH, learning how to collect evoked responses using scalp electrodes. Skillsto be acquired will include one or more of: medical image reconstruction;photogrammetric software use; medical image segmentation and meshingsoftware; EEG electrode placement and use; experimental design and dataanalysis. The project would be suitable for a single student or, preferably,team of 2 or 3, with a backgrounds in physics, engineering, computing, ormedicine.

Imaging in acute stroke with time difference Electrical Impedance Tomography: a simulation study.

SupervisorsProf. David Holder and Dr. Ana Plata.

Student: (Project available)

EIT is a novel medical imaging method, with which images of the electricalimpedance of the head can be produced with a box about the size of apaperback book, laptop  and EEG electrodes on the head.  It is portable,safe, fast and inexpensive.  The supervisor's research has been to developits use in imaging functional activity in the brain. One possible use couldbe to image changes in the brain during acute stroke over time as the brainpathology evolves. EIT has the unique potential to provide a bedside imagingmethod for this purpose which would alert medical staff to a deteriorationand so lead to improvements in treatment. Unfortunately, imaging over hoursmay be obscured by fluctuations in baseline impedance due to movement andchanges in electrode properties. The project will be to undertake a computersimulation study of the feasibility of imaging changes in stroke with realdata from clinical studies of the fluctuations in baseline. The student willfirst be trained in background literature, and use of simulation and imagereconstruction. They will then simulate the expected changes during aworsening stroke and then see if it is possible to produce acceptable imageswith the addition of realistic noise and boundary voltage drifts. If timepermits, an investigation will be made into signal processing methods whichcould improvement of the signal-to-noise ratio and so image quality.Skill to be acquired : : medical image reconstruction and computersimulation, data and statistical analysis and signal processing. The projectwould be suitable for a student with a background in physics, engineering,computing, or medicine.

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

SupervisorsProf. David Holder and Jacek Zienkiewicz

Student: (Project available)

EIT is a novel medical imaging method, with which images of the electricalimpedance of the head can be produced with a box about the size of apaperback book, laptop  and EEG electrodes on the head.  It is portable,safe, fast and inexpensive.  The supervisor's research has been to developits use in imaging functional activity in the brain. One excitingapplication lies in its use to image changes in the brain due to epilepticactivity. In epilepsy, abnormal activity may occur in the form of seizuresin which there is continuous abnormal activity lasting a minute or so.  EITcould be used to provide a uniquely new method for imaging brain activity insuch seizures which could be used in surgery for epilepsy.In order for this be realised, EIT needs to be recorded at the same time asEEG over several days in patients on a ward who have been specially broughtin for observation. Both are recorded with about 20 electrodes glued to thescalp. Unfortunately, the EIT injects an artefact into the EEG signal. Amethod for removing this has been developed but it currently takes severalminutes of post-processing off-line after the EEG has been acquired. As someclinicians need to see real-time EEG at the bedside as it is collected, itis desirable to run the cleaning algorithm in real time.The purpose of the project will be to implement and test real-timeimplementation of the algorithm. Initially, the student will read relevantbackground literature and become familiar with the algorithm. They will thendevelop a way to run it in real time, initially on a PC running in parallelwith commercial EEG software. If this is not sufficiently fast, then othermethods to speed up prcoessing will be investigated, such as the use of aparallel Graphical Processing Unit added to the PC.Skills to be acquired:  Skills to be acquired will include : programming inMatlab, C or C++, signal processing, and biomedical instrumentation. Theproject is suitable for a student with a background in physics, engineeringor computing, or a medical student with experience and an interest inprogramming.

Building and testing an electrical stimulator

Supervisors: Dr. Anne Vanhoest and (second supervisor to be confirmed)

Student: Tolulope J Mohammed

A stimulator to test electrical stimulation protocols is to be built and tested. The stimulator produces a controlled current-waveform for tripolar stimulation, where the current ratio between the 2 anodes can be adjusted. The student will populate the PCBs and test them electronically before preparing a box and building the stimulator. If this is successful, there will be an opportunity to perform some electrical stimulation experiments. The student is expected to solder the components and machine the enclosure. He or she must have some manual skills, an ability to work with drills and other basic workshop tools. No preliminary electronic knowledge is required, but the student should be keen to learn the basics of this subject. For more information on the research carried on in the Implanted Devices Group click here.

Control logic for a stimulator IC

Supervisors: Dr. Anne Vanhoest and Prof. Nick Donaldson

Student(s): (Project available)

This project is for one or two students with prior knowledge of electronic logic (and micro-controllers) and basic programming skills. There is currently a discrete control circuit for one of the IDG's stimulator IC that relies on a purpose-built FPGA. The students are to replace this circuit with a simpler and more user friendly logic controller, probably involving a micro-controller. Hence the pre-requisites of knowing some basic electronics, enough to understand the current circuit and design the new controller. It is open to either one student or a pair with good collaboration skills. For more information on the research carried on in the Implanted Devices Group click here.

Lamination of High-Temperature Co-fired Ceramic

Supervisors: Dr. Anne Vanhoest and Prof. Nick Donaldson

Student: (Project available)

In our cleanroom, we produce HTCC substrates for implantable medical devices. To refine our process, our heated press must be improved, and the lamination parameters optimised. This project involves some mechanical work to develop the heated press, then the student will run systematic tests, hence this would suit a well-organised person showing good analytical skills. For more information on the research carried on in the Implanted Devices Group click here.

Thick-film humidity sensors - a feasibility study

Supervisors: Dr. Anne Vanhoest and Prof. Nick Donaldson

Student: (Project available)

To study the feasibility of using standard thick-film methods to create an implantable humidity sensor. This project will first require a literature review, followed by a time in the lab, to characterize existing sensor candidates. If the progress are satisfactory and the student shows a good behaviour in the lab a second stage will involve researching other materials, suitable in terms of their bio-compatibility and sensing properties for the production of new sensors in the cleanroom. For more information on the research carried on in the Implanted Devices Group click here.

Testing the effect of exposure to high-temperature on the response of integrated humidity sensors

Supervisors: Dr. Anne Vanhoest and Prof. Nick Donaldson

Student: (Project available)

We have fabricated capacitive humidity sensor ICs to monitor the humidity level inside the cavity of our medical devices once implanted in a human body. The sensors are undergoing some long-term drift tests, and further tests are needed to assess the effect of exposure to high temperature (400C) on the sensor's response. The response of a set of 10 sensors is to be characterised in a controlled-humidity chamber before and after undergoing a temperature cycle. This will require some preliminary work to prepare the sensors for use in the humidity chamber, followed by result analysis. The sensors are small, fragile and valuable, therefore this project would suit a careful student with good manual skills, perhaps someone with a DIY hobby. For more information on the research carried on in the Implanted Devices Group click here.

An interactive e-learning tool for electrical stimulation theory

Supervisors: Dr. Anne Vanhoest and Mr Nathaniel Dahan

Student(s): (Project available)

In a first stage the student(s) will undertake a literature review to understand the basics of the theory of electrical stimulation, including notions of rheobase and chronaxie, with a focus on stimulation optimisation from a point of view of charges and energy. This is of importance for future development of electrical stimulators as minimising the energy per stimuli would improve the power requirements of the stimulator while the charge delivered may be linked to potential nerve damage if it is excessive. If two students share this project, the theoretical findings shall be integrated in an interactive e-learning tool showing several stimulus waveforms with adjustable parameters and calculating the charge and energy requirements. This project does not involve any lab work and is therefore suitable for students living further away. No prior knowledge of electrical stimulation principles is required. The student(s) must be comfortable with integrations and derivations as the first phase of the project is theoretical. If the project is undertaken by two students , it is strongly advised that one of them at least show some previous experience of designing web-interfaces, with user interactions and animations. For more information on the research carried on in the Implanted Devices Group click here.

Numerical Modelling of Ultrasound Propagation in Poroelastic Media using Pseudospectral and k-Space Methods

Supervisors: Dr. Ben Cox and Dr. Mark Thompson (University of Oxford)

Student: (Project available)

A poroelastic medium is one that consists of a solid skeleton with fluid pores within it. Bone is a clear example, although many tissue types can be modelled as poroelastic on some scale. This project will use spectral methods (numerical methods based on the Fast Fourier Transform) to develop a numerical model of ultrasound propagation in such media. The starting point will be Biot two-phase model extending the technique to more complex multi-phase models if sufficient progress is made. Some experience with tensor partial differential equations, a good understanding of numerical methods, in particular the Fast Fourier Transform, and confident Matlab or C++ programming skills will be required.

Numerical Modelling of the Detection of Photoacoustic Waves by an Atomic Force Microscope

Supervisors: Dr. Ben Cox and Bart Hoogenboom (London Centre for Nanotechnology)

Student: (Project available)

Atomic force microscopes can be used to detect the displacements in the surface of a material as ultrasound waves reflect from it, but it is not yet known if the low acoustic amplitudes typically generated by the photoacoustic effect can be detected in this way. The aim of this project is to develop a numerical model to predict the signals that might be measured in such an arrangement, and determine under what conditions it may be achieved in practice. If this is successful, a second part of the project could look at how such measurements might best be used to form an image of the sample being studied. A good understanding of partial differential equations, numerical methods and confident Matlab or C++ programming skills are essential requirements.

Numerical Modelling of Ultrasound Propagation Through Anisotropic Media

Supervisors: Dr. Ben Cox and Dr. Bradley Treeby (Australian National University)

Student: (Project available)

It is often assumed that the speed of ultrasound propagation through biological tissue is isotropic (does not depend on direction). This is not quite true for some tissues (bone, cartilage) especially at high frequencies. This project will develop a model of acoustic propagation taking into account sound speed anisotropy, and explore the resulting effects on the wavefield. A good understanding of partial differential equations, Fourier transforms, numerical methods and confident Matlab or C++ programming skills are essential requirements.

Developing a Nonlinear Image Reconstruction Algorithm for Contrast-Enhanced Photoacoustic Imaging

Supervisors: Dr. Ben Cox and Prof. Paul Beard

Student: (Project available)

The acoustic waves in conventional photoacoustic imaging are assumed to propagate linearly as the acoustic pressures are so low. The image reconstruction algorithms are therefore all linear. As new contrast agents are developed with high values of optical absorption, the early part of the propagation may be nonlinear. This project will investigate the use of time reversal as a nonlinear reconstruction algorithm, and determine whether this is likely to enhance image quality in practice. A good understanding of partial differential equations, Fourier transforms, numerical methods and confident Matlab or C++ programming skills are essential requirements.

Photoacoustic Image Reconstruction Using L-Shaped Detector Arrays

Supervisors: Dr. Ben Cox and Prof. Paul Beard

Student: (Project available)

Planar detection arrays have been used successfully for photoacoustic imaging. However, as the sensitivity of the devices and the signal-to-noise ratio improves it becomes clear that image artefacts appear due to the limited size of the detectors. One way to combat this is to use two perpendicular planar detectors in a V or L formation. Kunyansky has recently proposed reconstruction algorithms applicable to cases such as this. The project will have three objectives: to code up one of Kunyansky’s algorithms in 3D using Matlab, to test it with data simulated using k-Wave and to compare the images obtained with those from a single planar detector, and to compare the results with another image reconstrucion algorithm based on time-reversal. A good understanding of partial differential equations, Fourier transforms, numerical methods and confident programming skills are essential requirements.

Investigation into Staircasing Errors in Numerical Ultrasound Models

Supervisors: Dr. Ben Cox and Dr. Peter Munro

Student: (Project available)

Most numerical models of broadband ultrasound propagation use a regularly spaced mesh of points at which to calculate the field. Because the material properties are also defined at these points, curved interfaces between two materials (between soft tissue and bone, for example) are represented by a ‘staircase’ of square-edged steps. This can result in errors in the calculated field. One solution is to use an irregular mesh, but for some techniques (such as k-space methods) the regular mesh is integral to the technique. The aim of this project is to investigate the degree of error this introduces into the solution by comparing simulations using a pseudo-spectral k-space acoustic model with analytical results in various cases. If good progress is made, the related question of the best way to model a general impedance boundary condition in such models will be explored. A good understanding of partial differential equations, Fourier transforms, numerical methods and confident Matlab or C++ programming skills are essential requirements.

3D Ultrasound Imaging of the Prostate for Guiding Biopsy and Minimally-invasive Cancer Interventions

Supervisors: Dr. Dean Barratt, Yipeng Hu, and Mr. Hashim Ahmed (UCL Urology)

Student: (Project available)

Prostate cancer is now the most common cancer in men in the UK, North America, and many parts of Europe. Ultrasound imaging is used routinely in hospitals for guiding the placement of transrectal needles during prostate biopsy, a procedure in which prostate tissue samples are collected for subsequent histological analysis for the presence of cancer. Ultrasound is also used widely for guiding minimally-invasive cancer treatments, such a brachytherapy, where small radioactive seeds are implanted into the prostate. In practice, however, accurately guiding needles or seeds to the desired location is challenging using conventional ultrasound scanners, which only provide two-dimensional, cross-sectional views of the prostate. 3D ultrasound imaging offers a potential solution by allowing an image of the entire prostate (and surrounding structures) to be produced. This is useful because it allows needles, seeds, and other therapy delivery instruments to be located in three dimensions. 3D images are also required in order to accurately register (i.e. align) ultrasound images with MR images,  which enable tumours to be identified much more reliably than ultrasound images. The aim of this project is to develop an intraoperative method for acquiring and visualising 3D images during minimally-invasive surgical procedures, and to validate its accuracy using physical prostate models ("phantoms") that can be imaged using ultrasound and MRI.

Registration of MR and CT Images for Image-guided Radiotherapy Treatment of Prostate Cancer

Supervisors: Dr. Dean Barratt and Yipeng Hu

Student: (Project available)

Prostate cancer is now the most common cancer in men in the UK, North America, and many parts of Europe. External beam radiotherapy is a standard treatment for prostate cancer that involves the delivery of a series of radiation doses (called fractions) to the prostate gland. Conventionally, the entire prostate is treated, but recently there has been significant clinical interest in new therapy approaches in which the radiation dose is concentrated on a single (dominant) tumour to reduce the risk of side-effects through "collateral damage" to nearby structures, such as the rectum, nerves, and bladder. Implementing this approach relies on the ability to precisely locate the tumour at the treatment planning stage and within the radiotherapy system at the start of each fraction. This is complicated by the fact that prostate tumours are generally not visible in CT scans used for treatment planning and dosimetry, or in on-board x-ray images used for patient positioning during therapy. For this reason there is a need for methods for registering (i.e. aligning) information on tumour location from MR images with CT and x-ray images to enable tumour targeting both at the planning stage and during therapy. In this project, the accuracy of a marker-based technique for MR-CT image registration will be evaluated, which involves aligning markers implanted into the prostate. Special attention will be paid to assessing the affects of prostate deformation between MR and CT images, and devising methods for overcoming this.

Development of a clinical protocol for MR-to-ultrasound image registration during prostate cancer HIFU therapy

Supervisors: Dr. Dean Barratt and Yipeng Hu

Student: Babatunde Gafaar

This project will involve: a) Becoming familiar with the new image registration software we have developed for fusing MR information on prostate tumour location and size onto transrectal ultrasound (TRUS) images acquired during HIFU therapy procedures. This information is used to delivery therapy to a region encompassing the tumour more accurately than conventional "eyeballing" (sometimes referred to as "cognitive registration"). We are the first group in the world to use this technique for HIFU; b) Evaluating the impact of inter- and intra-observer variability associated with critical stages of the registration process (principally, manual contouring of the prostate gland on MR images and identifying prostate surface points in TRUS images during a HIFU procedure; c) Devising a clinically practical protocol for the registration process based on quantitative data from part (b). The aim is to devise a protocol that maximises accuracy but minimises operator variability; d) Evaluating the difference between intra-operative registration (peformed in the time-critical setting of the operating theatre) and off-line registration.