MPHY3000/MPHYM000: Medical Physics Projects 2009-10

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 19, 2009. 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 18, 2010.
  • Project talks will be held on Wednesday March 17, 2010 in Rooms 1.19 and 2.14 of the New Engineering Building in Malet Place.
  • Final Reports are due by Friday March 23, 2010. Please hand in to the Medical Physics Departmental Office (second floor of the Malet Place Engineering Building).

Project information

Developing a Medical Physics forum website.

Supervisors: Dr. Nick Everdell and Prof. Jem Hebden

Student: UG or MSc.

Thu pupose of this project is to design and build a ‘proof of concept’ website that could be a very useful resource for the department and possibly the Engineering Faculty as well. The website will be a ‘resource centre’ for the department, and would have three main strands: 1) A discussion forum where staff and students could post their technical problems and questions. 2) A database of departmental expertise. The idea here is that anyone within the department could consult this to find out who the best person would be to talk to about a particular problem. 3) A database of departmental resources and facilities. These three elements would link together in some way to enhance the site’s usefulness. The purpose is to promote the free exchange of ideas, skills and resources between staff members (and students), something that does not always happen that well at the moment. Part of the project would involve the preparation and distribution of questionnaires around the department, to gather information for the database. This project will obviously require some interest in and/or knowledge of web programming. If the concept can be shown to work well for the Medical Physics department, it could then be implemented faculty wide (the ‘faculty forum’), where we envisage it becoming a widely used resource.

Designing and constructing a cylindrical tissue-equivalent phantom for evaluating simultaneous EEG and optical imaging.

Supervisors: Prof. Jem Hebden and Rob Cooper

Student: Robin Eames.

Researchers within the UCL Biomedical Optics Research Laboratory (BORL) are attempting to simultaneously display the electrical and haemodynamic changes associated with brain activity. This work uses an optical imaging system which has an array of optical fibres placed in contact with the head, combined with an array of EEG electrodes. The project will initially involve designing and building a hollow cylinder (based on a combination of polyester resin and thin conducting wires) through which light and electrical currents can pass. The cylinder will then be filled with an optical-scattering / electrically-conducting liquid. Measurements will be made using optical fibres and electrodes placed on the surface of the cylinder as appropriate targets/electrical sources are moved within the liquid. Data will be analysed and images will be generated. This project is most suitable for a student who enjoys building mechanical and/or electrical devices and has good manual skills.

Development of a dynamic tissue-equivalent phantom for 3D optical tomography, based on electrically-heated thermochromic pigments.

Supervisors: Prof. Jem Hebden and Dr. Louise Enfield

Student: Oliver White.

Optical tomography is being developed at UCL as a means of imaging the newborn infant brain. The technique involves measuring the flight-times of photons as they pass across the tissue. Optical images reveal the distribution of blood within the brain, and show how well it is oxygenated. The technique can be used to monitor brain activity, and to detect various abnormalities such as haemorrhage and stroke. This project will involve making a cylindrical solid block of resin with tissue-like optical properties in which are embedded discrete targets containing a thermochromic dye. A series of targets will be placed at different locations, which can be electrically heated independently. The UCL optical tomography (known as MONSTIR) will be used to image the changes in light absorption which occur when each target is heated. The imaging system has an array of optical fibre bundles, which allows measurements to be made of near-infrared photons which scatter across the phantom. These measurements can be converted into images using computer programs developed at UCL. Further details about the imaging system can be found at: http://www.ucl.ac.uk/medphys/research/borl/imaging/monstir/inst . This project is most suitable for a student who enjoys building mechanical and/or electrical devices and has good manual skills.

Development of a simple “Monte Carlo” computer program for simulating light travel in biological tissue

Supervisors: Prof. Jem Hebden and Dr. Adam Gibson

Student: Vicknesh Aruljoethy.

This project is intended for a student with either a little experience of computer programming, or a willingness and interest to learn. The first part of the project will involve developing what is known as a “Monte Carlo” model of light scattering in a known volume from first principles. The computer program will use some very simple equations which govern the probability of light photons being scattered in a particular direction in order to model the paths of individual photons as they are scattered from one point on the surface of a (rectangular) volume to another point. The second part of the project will involve examining how the “mean path length” for photons travelling between two given surface points is influenced by the presence of absorbing targets placed inside the medium. The third part would involve comparing the model with a simple experimental measurement. An optional fourth part (which would only be attempted if there was time) would be to systematically vary the parameters of the model from a uniform starting point in order that the model predictions could be made to match experimental measurements. This then becomes a method of "imaging" the targets within the volume.

Obtaining initial estimate of optical parameters.

Supervisors: Dr. Adam Gibson and Prof. Jem Hebden

Student: UG or MSc.

A time-resolved optical imaging experiment yields up to 1024 distinct histograms of photon arrival times (click here for technical details). These are measurements correspond to different lines-of-sight across the same object, using different source-detector combinations. The purpose of this project is to model the data analytically and obtain a fast estimate of the mean optical properties throughout the whole object. This project would be suitable for a student with an interest in computer programming and will involve some mathematics.

Measurement of optode locations using mean flight-time and intensity.

Supervisors: Dr. Adam Gibson and Prof Jem Hebden

Student: UG or MSc.

Our optical imaging works by shining light from each connector in turn and measuring light from other connectors. The time taken for the light to travel across the body depends on the distance travelled and the optical properties of the body. If we assume the optical properties to be constant, it should be possible to use the measurements of photon transit time to calculate the separation between the connectors, and hence their locations. This project will determine whether such a method can work, and the likely errors. This project would be suitable for a student with an interest in computer programming and will involve some mathematics.

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

Supervisors: Dr. Nick Everdell and Dr. Salavat Magazov

Student: Abdulla Ghaly

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.

Pulse plethysmography using an optical mouse

Supervisors: Dr. Adam Gibson and Dr. Nick Everdell

Student: Amena Noorani

An optical mouse consists of an LED and a photodetector. It is possible to modify certain types of mouse so that the detector can be read out using a serial port. This project will involve selecting a mouse and making appropriate modifications so that it can be used to detect pulsatile blood in the finger. This project is intended to lead to a demonstration of medical optics which can be used in school practical classes.

Comparison of optical mammography of the compressed and uncompressed breast.

Supervisors: Dr. Louise Enfield and Dr Adam Gibson

Student: Bahareh Gholipour

Optical imaging techniques are being developed at UCL as a means of imaging the adult female breast to detect breast cancer. There are two main approaches to optical mammography: imaging the compressed breast or the uncompressed breast. In this project, the student will construct a compressible anatomically-realistic optical  phantom containing features of known size and contrast. This will then be imaged using our optical tomography system in compressed and uncompressed geometries, and then the images will be analysed to compare the two methods.

Reproducibility of optical images of a breast phantom

Supervisors: Dr. Louise Enfield and Dr Adam Gibson

Student: Adam Telford

Optical imaging techniques are being developed at UCL as a means of imaging the adult female breast to detect breast cancer. One of the research areas of interest is using optical imaging to monitor the response of a tumour to chemotherapy. Repeat scans will be carried out on the same patient several times during the course of treatment. The positioning of the patient and the reproducibility of the images are important to the success of the clinical project. In this student project, the student will use anatomically-realistic optical phantoms containing features of known size and contrast, and devise methods to ensure correct placement of the phantom before performing repeat scans using our optical tomography system. The images will then be assessed for reproducibility.

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

Supervisors: Prof. Alan Cottenden, Raquel Santamarta and Prof. Jem Hebden

Student: Emily Krimholtz

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).

Measuring the permeability of superabsorbent polymers

Supervisors: Prof Alan Cottenden and David Cottenden

Student: UG or MSc

Superabsorbent polymers (SAP) are remarkable materials capable of absorbing more than 100 times their dry weight in water. They are much used in absorbent medical and hygiene products, as well as in food packaging (for example, to absorb meat juices) and spill sorbents. To exploit their properties optimally we need to measure their permeability when hydrated (how easily fluid flows through them under pressure) but this is difficult to measure. This project will involve developing a method - using a simple, recently built flow cell - to measure the permeability of four SAPs supplied by BASF (the world’s biggest supplier, with whom we are working). Time permitting, the data will be used to test theoretical models for SAP performance. The project will be primarily experimental and based at the UCL Archway campus (by Archway tube station).

Development of a new laboratory method for characterising the leakage performance of experimental absorbent materials

Supervisors: Prof Alan Cottenden and Raquel Santamarta

Student: Maria Gkika

The Continence and Skin Technology Group is currently collaborating with two other universities and five companies to develop a new washable absorbent pant for lightly incontinent women. As part of the project, we have developed a test rig for measuring how much fluid a pad will hold under standard conditions before it leaks. Currently, we simply apply fluid at 2 ml/s until leakage occurs. The proposed project will involve investigating the impact on pad performance of using different flow rates and intermittent dosing patterns which may better reflect real use. The methodology developed in the project will be used to evaluate experimental fabrics provided by Leeds University and the data will be fed into our ongoing product development work. The project will be a mix of experiment and theory and based at the UCL Archway campus (by Archway tube station).

Investigation of a new device for measuring water vapour flux density from skin

Supervisors: Prof Alan Cottenden and Rob Heggie

Student: UG or MSc

In the last couple of years students and staff at the Continence and Skin Technology Group have characterised the performance of a range of devices for measuring the water vapour flux density from skin, an important measure of how wet skin is – for example, having been wearing an incontinence pad. This work has involved comparing various devices inter alia and calibrating them to reveal their accuracy and limitations. Recently, a new device has become available and this project will involve investigating and quantifying its performance to see if it is any better than earlier devices. The project will be primarily experimental with the possibility of some mathematical modelling, and it will be based at the UCL Archway campus (by Archway tube station).

Investigation of a device for measuring the volume of urine loss in incontinent people

Supervisors: Dr. Martin Fry, Prof. Alan Cottenden and Rob Heggie

Student: Hassan King

IThe Urilos nappy is a diagnostic device which comprises a pad with a capacitive sensor imbedded in it. When the pad becomes wet the capacitance of the sensor changes (the dielectric constant for wet and dry pad differ) and it is claimed that, once calibrated, it is possible to estimate the volume of urine in the pad from the change in capacitance. However, anecdotal evidence suggests that the readings are heavily dependent on where in the pad the fluid arrives; the flow rate at which it arrives and the shape of the worn pad. This project will involve a controlled laboratory investigation in which the output of the device is studied for various volumes, flow rates, points of fluid application and pad geometries. We would also like to investigate the potential for estimating leakage flow rates by differentiating the capacitance change with respect to time. The project will be primarily experimental with the possibility of some mathematical modelling, and it will be based at the UCL Archway campus (by Archway tube station).

History of Electrotherapy

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: UG or MSc

A recent book from a Cambridge historian (Fara P., An Enlightenment for Angels, Icon Books, 2002) shows that electrotherapy, treating illnesses by the application of electricity to the body, started immediately following the invention of the Leyden Jar in the 1740s. It seems to have been a thriving business during the remainder of the 18th century and continued in the 19th century. As recently as the 1920s, text books on the subject were appearing with recommendations for treating all manner of complaints. However, in Britain, by the 1970s, the methods had been abandoned except perhaps by some physiotherapists. 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.

It would be interesting to know how widely electrotherapy was used and why it fell out of use early in the 20th century. We propose that an interesting project would be to investigate these questions using the resources of the Wellcome Library of the History of Medicine (on Euston Road). The study should aim to understand the treatments used, described in modern scientific terms, but also critically appraise the methods, at least concerning the physics involved (but not necessarily the neurophysiology).

An Implantable Movement Sensor

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: Jorge Chacon Caldera

A closed silicone rubber tube, filled with isotonic saline and implanted in the body, will be in osmotic equilibrium, neither gaining nor losing volume. If electrodes are placed at the ends of the tube, the impedance through the saline can be measured and this may change as the tube is stretched or bent. A thin tube could therefore make movement sensor: we want such devices to detect changes in the shape of the bladder (as part of a system to prevent incontinence). What is needed is a simple method to measure the tube resistance through the skin. One possibility, using radio-frequency induction, is to arrange two resonant circuits (inductor-capacitors pairs) coupled through the variable resistance. If one resonant circuit is excited by a short burst of radio-frequency energy from an external transmitter, can we use the time course of the magnetic field generated by the second resonant circuit to show the resistance? The advantage of such a system is that it uses components that can easily be protected from body fluid, and should be independent of the magnetic coupling from the external transmitter.

The project will be to develop such a system on the bench (if possible). Prior experience of electronics will be helpful but not mandatory.

Understanding the effect of surface roughness on electrode impedance

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: UG or MSc

A polarisable electrode like platinum has an impedance that has both capacitance and resistance but these are not combined in a simple way. Over a range of frequency that is useful to recording nerve activity, such an electrode may have a nearly constant phase angle of about 70 degrees. Part of the reason for this strange behaviour is thought to be due to the roughness of the surface. The interface itself may be perfectly capacitive but the roughness means that some of the surface capacitance is accessed through the resistance in tissue within the crevices. The electrode then has a distributed structure which may have the measurable constant-phase characteristic. In this project, the effect of different types of roughness will be explored using models made from resistors and capacitors in 2D arrays. Models will be made with crevices of different depths and different profiles (convex and concave). The impedance of these models will be measured on an Impedance Analyser that plots impedance over the chosen range of frequency.. One aim will be to see what type of roughness can give a phase-behaviour like platinum, assuming that the platinum-saline interface itself is purely capacitive.
An enjoyment of model-making and mathematics will be helpful in this project.

Wind Turbines in the Jet Stream: a feasibility study

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: UG or MSc

The power from wind turbines rises as the cube of the wind speed. The speed of the jet stream is sometimes 200 miles per hour. Obviously the power that might be extracted could be enormous. However the course of the jet stream moves over the earth’s surface and is high in the atmosphere. Might turbines be placed in the jet stream to extract some of this power? One idea is to fly a large kite, which lifts the turbine, from a ship that moves about the ocean under the jet stream. Electricity from the generator could electrolyse sea water and the hydrogen could be stored in the ship.

This is a project for two students who should come up with one concept and then write two reports about its feasibility, One should report on the engineering aspects; the other on the meteorological and economic aspects of this concept. Good reports should use stated principles of engineering; use data from references; and be generally quantitative rather than merely descriptive. Of course it is essential that none of the possible difficulties (for example: the weight of the wire going to the kite) is neglected.

Electrical nerve stimulation: designing, producing and testing a portable stimulator

Supervisors: Dr. Anne Vanhoest and Prof. Nick Donaldson

Student: Nimesh Shah

Computer models are increasingly replacing real nerves to test new stimulation concepts. While this is necessary at the early stages of development, the simplifications intrinsic to the model limit its usefulness as it is not a true representation of in vivo electrical stimulation. To avoid setbacks during chronic experiments it is important to keep controlling the efficacy of new stimulators and electrodes against real nerve in vitro. At the Implanted Devices Group we have used xenopus sciatic nerves to improve our understanding of stimulation due to current spread and compare proposed stimulation methods against our experimental stimulator. This project, for one or two students, is to build and test a new experimental stimulator based on the current one. The project involves designing, making, populating and testing the pcbs for the new stimulator as well as packaging it in a convenient and robust manner. Depending on the qualifications of the student(s), parts of the current circuits will be re-designed and the finished stimulator will be used in tests on explanted xenopus sciatic nerves.

The project is open to one or 2 students, whether at B.Sc. or M.Sc. level, with a basic understanding of electronics (resistor, capacitor, comparator and integrator) and a willingness to get away from the pc and “make things” (pcb, box). If 2 students are interested but only one of them has the electronics knowledge while the other has some understanding of nerve physiology, the experimental part of the project could be expended. It will then be important for both of them to demonstrate their ability to work as a team, supporting and complementing one another.

Implementation of de-blurring routines

Supervisors: Dr. Caroline Reid and Prof. Robert Speller

Student: UG or MSc

Conventional projection radiography is the most widely implemented method of x-ray screening methods, be it mammography, security screening of passenger luggage or quality control of industrial products. This method can be limited, firstly, through effective ‘stacking’ of objects in a projection image resulting in flattened images from which it is difficult to discriminate objects and, secondly, distortion of image information due to variations in x-ray absorption properties of imaged structures, for example, difficulty in distinguish between a thin sheet of strong absorber and a thick slab of weak absorber. These effects can lead to important information from the screening process being overlooked. It is proposed that this may be overcome through the use of digital x-ray tomosynthesis, an imaging technique currently attracting much attention in the medical imaging field. Tomosynthesis is a refinement of conventional geometric tomography methods where a finite number of projection images are acquired at varying orientations of the x-ray tube around the imaged object, from which a 3D image of the object is created. From these 3D images retrospective reconstruction is used to create focussed 2D slice images of an arbitrary number of planes through the object. It is proposed this method will be performed on objects moving on a conveyor system, leading to the name ‘On-belt Tomosynthesis’ (ObT).
Typically in tomosynthesis, a set of slice images are generated from the summation of a set of shifted projection images acquired at different orientations of the tube. This is referred to as the Shift-and-add (SAA) reconstruction. This SAA reconstruction takes into consideration the fact that the projection of objects at different heights above the detector will be dependent on the relative heights of the objects above the imaging plane. While one benefit of the SAA image reconstruction method is the small computing power required to run the algorithms, the resulting images are heavily affected by blurring as they contain images from every plane of the imaged object; one plane in focus and all the others smeared on top. Code for the SAA image reconstruction method has been developed. This project aims to implement a number of de-blurring routines, implemented on top of the SAA image reconstruction method, have been developed to remove artefacts and improve the reconstructed image quality. Test procedures will then be developed to assess the relative image quality of the reconstructed images. This project would be suitable for a student with an interest in computer programming and will involve mathematics.

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

Supervisors: Dr. Sandro Olivo and Prof. Robert Speller

Student: UG

X-ray phase contrast imaging is a new imaging modality 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 z-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.

Intelligent CT

Supervisors: Prof. Robert Speller and Dr. Peter Munro

Student: UG or MSc

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 Dr. Konstantin Ignatyev

Student: UG

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.

The Bazooka: an ultra-high resolution gamma imaging camera for nuclear medicine

Supervisors: Dr. Gary Royle and Dr. Ian Cullum

Student: Kiran Easwaran

Nuclear medicine images distributions of radioactively labeled pharmaceuticals in the patient for diagnostic purposes. Image quality is generally poor in comparison with techniques such as CT or MRI due to the imaging cameras employed. Generally this is acceptable because the clinician is looking for functional information rather than anatomical detail, but there are situations when very high spatial resolution images are required. This project will construct and evaluate a nuclear medicine camera capable of achieving very high spatial resolution images.
It is based on a highly sensitive CCD camera coupled via an optics system to a coded aperture collimator. The project will involve instrument development, experimental measurement and development of computer codes for controlling the camera and processing the images. The aim of the project will be to determine the spatial resolution that can be achieved and the minimum level of radioactive pharmaceutical that can be used to generate an acceptable image.

Development of breast density measurement technique for cancer screening

Supervisors: Prof. Robert Speller and Ben Price

Student: Sarah Staight

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.

Monitoring tissue oxygenation and energy metabolism in muscle and brain using novel optical instrumentation

Supervisors: Dr. Ilias Tachtsidis and Prof Clare Elwell

Student: Jabed Ahmed

Monitoring the tight balance of brain blood flow, oxygen delivery and brain tissue metabolic rate is a major aim in patient diagnosis and care. For several years our group has pioneered the development and use of non-invasive methods and instrumentation that are based on near-infrared spectroscopy (NIRS) to provide information on the status of the brain tissue. NIRS is an optical technique that uses harmless low light levels that can penetrate the skull and reach the brain tissue; from the detected reflected light we can resolve the major tissue chromophores. While typically NIRS measurements are based on two light wavelength systems, therefore able to resolve only for the concentrations of oxygenated and deoxygenated haemoglobin; we have recently acquired a multi-wavelength (7 wavelengths) instrument that allow the measurements of additional molecules and hence provide measurements on the distribution of oxygen and blood in the brain and how oxygen is being utilised by the brain. The students will set up the 7 wavelength NIRS spectrometer and design experimental protocols that will allow testing the system and collecting data from volunteers and patients. In particular the experimental protocols will involve a combination of: (1) measuring muscle oxygenation during exercise, (2) monitoring the brain during task activations such as anagram solving and video gaming and (3) monitoring anaesthetised patients before, during and after brain surgery. Experiments will be conducted both in our labs in Medical Physics and/or National Hospital for Neurology and Neurosurgery. This project will divided between two students each of whom will concentrate on different experimental protocols and appropriate analysis method. This project would be suitable for students with an interest in experimentation, data collection, and human physiology; and will involve data processing and some statistical analysis.

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

Supervisors: Dr Ilias Tachtsidis and Prof Clare Elwell

Student: Paul Lei

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 a commercial available near-infrared spectrometer (NIRO 300, Hamamatsu Photonics). The main focus for this project will be the data analysis of physiological signals obtained before and after brain injury and during hypothermia treatment. 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 benefits of implementing this treatment 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 some statistical analysis.

Development of a tissue-mimicking phantom for acousto-optic imaging

Supervisors: Dr. Terence Leung and Prof. Jem Hebden

Student: Nadir Chowdhury

Acousto-optics is a new hybrid optical and ultrasound technique for biomedical imaging and monitoring. It involves using focused ultrasound to modulate local optical properties which in turn alter the phase of light passing through the focal zone. Light is diffused in tissue and the localization of light cannot be performed directly. The acousto-optic technique provides a way to localize the light and can therefore achieve higher spatial resolution than conventional optical imaging in turbid medium. Potential applications include imaging of the breast, the neonatal brain, and vasculature. The aim of this project is to build and test a tissue-mimicking phantom with both acoustic and optical properties similar to real human tissues. Phantoms will be made in different geometries to simulate various body parts such as the breast, brain and finger. The phantoms will form an essential part of a series of acousto-optic experiments to optimise the technique. This project is best suited to a student who enjoys building models and performing scientific measurements.

Two photoacoustics projects: (1) Photoacoustic Imaging: Can prior information be used to reduce the effects of limited-view detection? (2) Photoacoustic Imaging: what is the best reconstruction algorithm when there are unknown acoustic heterogeneities?

Supervisors: Dr. Ben Cox and Dr. Bradley Treeby

Students: (1) UG  and (2) UG

In biomedical photoacoustic imaging, pulses of laser light are used to generate ultrasound signals which can be used to form an image of the absorbed optical energy in the tissue. Over the last few years, it has been shown to be well suited to imaging blood vessels and capillaries in small animals and humans in vivo. Additionally, it has potential as a technique for imaging some types of cancer, and – particularly as targeted contrast agents are developed – distributions of specific biomolecules, such as proteins, within soft tissue. The Photoacoustic Imaging Group in the department of Medical Physics and Bioengineering (one of the first and leading groups for photoacoustic imaging research) has recently released the first version of a Matlab Toolbox, “k-Wave” (www.k-wave.org), for simulating photoacoustic wave generation and image reconstruction. These projects would use the k-Wave toolbox to investigate two areas of current research interest, and to design and write tutorial examples based on them for inclusion in future releases of the toolbox. Two topics of particular interest at present are: how best to form a photoacoustic image from the measured acoustic data when there are acoustic heterogeneities present in the tissue (which will always be true to some extent), and how to reduce the artefacts on images generated from measurements made using incomplete measurement surfaces. These projects, which are entirely numerical / computational, would be carried out using Matlab on the computers in the undergraduate computer room, first floor, Malet Place Engineering Building. Some familiarity with programming is necessary, and a basic knowledge of Matlab, though ideal, is not essential.

Development of an interactive teaching aid to demonstrate the principle of magnetic resonance imaging (MRI)

Supervisors: Prof. Roger Ordidge and Dr. Terence Leung

Student: UG or MSc

Equations can be quite confusing sometimes. Students often love the stories behind the equations but feel totally lost when they see the mathematical symbols. To untrained eyes, it may be difficult to appreciate how the variables in the equation can influence the final result, especially when non-linearity is involved. Students can gain enormous insight if they can interact with the equations and see the impact instantly. The latest version of Mathematica (a popular computational software) has made it easier than ever before to implement interactivity, e.g. slider. The aim of this project is to develop an interactive teaching aid based on Mathematica  to demonstrate the principle of magnetic resonance imaging. This project will suit a Physics/MedPhys student who has computer programming experience, and is willing to take up the challenge of revealing the secrets of equations!

An investigation in the use of superabsorbant particles (SAPs) as a method to prevent tumour growth

Supervisors: Prof. Roger Ordidge and Prof. Alan Cottenden

Student: Fiona Jones

Super-Absorbent Particles (SAP's) rapidly expand in the presence of water and if applied in the vicinity of a tumour, could be used to block blood vessels and thereby curtail tumour growth and possibly kill existing tumourous tissue. The project will involve an extensive literature search of related applications followed by simple experimentation of the ability of SAP's to block fluid flow of certain biologically relevant pressures. These will be conducted by injection of SAP's into plastic tubes of relevant diameter and a determination of the effects of fluid temperature and salinity to cease flow. This will be followed by an investigation of the use of tumour antibodies to be linked with the SAP's in order to target specific tumours and the most desirable characteristics of the SAP's to expand at the correct rate without infection of nearby healthy tissue.

Electrical Impedance Tomography (EIT) of evoked physiological activity

Supervisors: Prof. David Holder and ????

Student: Karan Kanal

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. The students will 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. The student 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: a) Medical image reconstruction; b) Photogrammetric software use; c) Medical image segmentation and meshing software; d) EEG electrode placement and use; e) Experimental design and data analysis. Would suit a student with a background in Medical Physics, Engineering, Computing or Medicine.

Electrical Impedance Tomography (EIT) of acute stroke

Supervisors: Prof. David Holder and ????

Student: Jonathan Cornell and Joshua Luis

EIT is a new medical imaging method which could be used as a portable and non-invasive way to image in acute stroke. It physically comprises a box of electronics about the size of a paperback book, laptop computer and use of ECG type electrodes placed around the body part of interest. New clot-busting drugs are available for the treatment of stroke but can only be given after a head scan as it is only safe when the stroke is due to blockage of an artery by a thrombus; it cannot be given if there is a haemorrhage. This can be undertaken by urgent CT but this is often not available. EIT could provide a method for imaging in an ambulance or in casualty departments at low cost, using a system, which is similar to an EEG machine, and 30 electrodes on the head. A state of the art EIT system has been developed which is ready for clinical testing in patients with acute stroke at UCH. In the project, suitable patients will need to be identified on the same day as arrival in the hospital. Electrodes will be applied to their head and a recording lasting about 20 minutes will be made with the EIT system. 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 “gold standard” images of diffusion weighted MRI taken at UCH. The student will spend time in the hospital helping identify suitable patients and making the recording, and in the lab in Medical Physics at UCL analysing the data. Skills to be acquired will include one or more of: a) Medical image reconstruction; b) Photogrammetric software use; c) Medical image segmentation and meshing software; d) EEG electrode placement and use; e) Experimental design and data analysis. Would suit a student with a background in Medical Physics, Engineering, Computing or Medicine.

Design of program for a thermal threshold testing machine used in the hospital to diagnose small fibre neuropathies

Supervisors: Prof. David Holder and Dr. Tongin Oh

Student: UG

In clinical neurology, patients may get a generalised abnormality of their nerves, which causes numbness and pain and is termed a peripheral neuropathy. This usually affects the larger nerve fibres, and this may then be diagnosed with nerve conduction studies. Sometimes, the small fibres which subserve pain and temperature are affected. This may be diagnosed with a thermal threshold technique, with which a metal pad is placed on the foot, and the subject is asked to comment when they feel it become warmer or cooler. In patients with a small fibre neuropathy, the thresholds are increased. The supervisor works both in Medical Physics and at UCH as a Clinical neurophysiologist. UCH has a thermal threshold system that was designed in the 1980’s and is now in need of updating. The purpose of the project is to improve the software used in this system, review if the threshold strategy needs improvement, and recalibrate it in a study in normal subjects. If time permits, the electronic circuits will be reviewed and a plan for fabrication with more modern components will be designed and this may lead to commercial collaboration. The student will learn programming in C and C++, interfacing with a PC via the serial port, nerve conduction studies and design and analysis of physiological data in human subjects. Would suit a student with a background in Medical Physics, Engineering or Computing. Some programming experience and interest is required.

Assessment of a novel method for automated EEG analysis

Supervisors: Prof. David Holder and Dr. Tom Tidswell

Student: UG

In Electroencephalography (EEG), about 20 voltages are recorded from the scalp, over about 20 minutes. These are subsequently analyzed, to see if there are abnormalities in conditions such as epilepsy. The analysis is currently undertaken by a Clinical Physiologist and medically qualified Consultant. Methods have been developed to analyse records by computer, in order to quantify the information and save time. These employ the power of modern computers and are intended to speed up the laborious process of visual analysis of many pages of EEG. In the supervisor’s group, a novel method for automated analysis of the EEG has been developed, which employs independent component analysis and a quadratic classifier. It is written in Matlab. The purpose of this project is to assess the accuracy of this new method on a group of about 30 EEG recordings in normal subjects. The outcome will be a comparison of its accuracy compared to visual identification by an expert and should lead to a peer reviewed publication in a scientific journal. The student will spend some at UCH in the supervisor’s department learning the basic of EEG collection and analysis, and learn how to use the newly developed Matlab based EEG analysis software. They will then run it on the EEG records and use statistics to compare the results with the “gold standard” of visual inspection. Skills to be acquired will include one or more of: a) Matlab programming; b) Simple medical statistical analysis; c) EEG use; d) Experimental design and data analysis. Would suit a student with a background in Medical Physics, Engineering, Computing or Medicine. Some experience in programming, ideally with Matlab, would be desirable.

Development of an interactive learning tool for diagnostic imaging

Supervisors: Dr. Jenny Griffiths and Dr. Gary Royle

Student: UG

We would like to develop an interactive tool that will give future students an insight into the effects of various parameters on the images produced by different diagnostic radiology techniques: computed tomography, planar imaging, SPECT, PET etc. The tool will show the changes in the resultant image as students change parameters associated with the image acquisition, such as spatial resolution and system noise (to name just two of many). This is a software development based project and will involve an assessment of the most suitable software packages for creating (and using) such an interactive tool, creation of a detailed plan of the tool to be produced, and then programming in the chosen software package to create the interactive tool for a given diagnostic radiology technique.

Investigation of image texture in Magnetic Resonance Images as a new contrast mechanism

Supervisors: Prof. Roger Ordidge and Dr. David Carmichael

Student: UG

Magnetic resonance (MR) image texture can be exploited to investigate structure that lies beneath the resolution power of MR images. The newly developed SPENT method can potentially provide a quantitative measure of bone strength without prolonged scanning or biopsy of bone samples, leading to potential applications in the diagnosis and assessment of the progression of osteoporosis. This project will simulate bone structure and investigate, using MATLAB simulation, whether directional bone strength may me mapped out throughout the important bones in the body that might be at particular risk of fracture. The student must be willing to learn programming using the commonly used MATLAB package and be expected to learn MRI principles in some detail.

Construction of radiofrequency coils for micro-magnetic resonance imaging

Supervisors: Prof. Roger Ordidge and Dr. Anthony Price

Student: UG

Small radiofrequency (RF) receiver coils are required to obtain the maximum sensitivity from small (sub-centimeter) samples scanned using Magnetic Resonance Imaging. This can be translated into higher resolution MR images. In order to gain this increased sensitivity, the RF coil, which is a simple tuned circuit, must be as small and close to the sample as possible. A variety of designs will be tested for ease of use and sensitivity to achieve this goal. An initial application is in phenotyping genetically engineered mice and mouse embryos for the structural and functional consequences of genetic modifications that might mimic human disease conditions. Please contact the supervisor for more details. Some practical skills would be useful or the student must be willing to learn these skills, and they will be expected to learn MRI principles in some detail.

Development of a MATLAB based FES cycling model

Supervisors: Prof. Nick Donaldson and Kylie de Jager

Student: UG or MSc

FES (Functional Electrical Stimulation) has been successfully used to enable SCI (Spinal Cord Injured) patients to stand in clinical trials. However, this is a complicated process that is not popular for home use. FES cycling is an alternative that has generated a considerable amount of research over the last decade or so as it is relatively simple to use at home, outside of the clinical environment. Nonetheless, the recreational use of the technology still has limitations, predominantly due to the low efficiency and power output generated by SCI persons, as compared to that of AB (Able Bodied) cyclists. The goal of this project is to develop a biomechanical model for FES cycling. Such a model would ultimately serve as a tool to investigate the relationship between muscle activation and the final output power generated. A model, developed by Riener and Fuhr1, for FES standing, will be adapted to build the cycling model. The current model, implemented in MATALB and Simulink, consists of a three-segmental model (shanks, thighs and upper body) and 9 mono- and bi-articular muscle groups. A combination of functional blocks, each block describing some aspect of the FES process, are used to simulate movement. The blocks can be grouped as follows: Electrical stimulation; Muscle activation; Muscle force; Generation of joint moments; Resultant movement. The student will have to adapt the model from that of a seated subject standing up, to a recumbent cycling position where the legs pedal against a variable load. An interface is also required that allows the model parameters to be set, such as the selection of which muscle groups to stimulate and the pedal position at which the stimulation starts and stops. The simulated muscle force and joint moments can then be used to determine output power generated. Graphics depicting the resultant movement will also be required.

The use of an inkjet printer to generate test sources for gamma ray detectors

Supervisors: Ian Cullum and Kjell Erlandsson

Student: UG

Small RF receiver coils are required to obtain maximum sensitivity from small (sub-centimetre) samples. A variety of designs will be tested for ease of use and sensitivity. Anger gamma cameras are used to obtain images of the distribution of pharmaceuticals labelled with radionuclides (radiopharmaceuticals) within the body. Detector performance is checked with known distributions of radioactivity prior to use to ensure their correct functioning. These test sources are often referred to as phantoms. They may take the form of simple distributions (for instance point sources, line sources and uniform ‘floods’) or more complicated ones mimicking the uptake of the pharmaceutical in various organs. Traditional phantoms are produced by filling perspex or glass containers with activity. Whilst this works well for the simple phantoms it becomes increasingly difficult (and expensive) to produce and fill those that mimic complicated distributions. Accurate and reproducible filling can also be difficult An additional problem arises if the phantoms are used with long-lived radioactive materials and need to be reused with a different radioisotope before sufficient decay time has elapsed. Some radiopharmaceuticals stick and concentrate on the perspex leading to artefacts in the phantom. A project several years ago showed the feasibility of using an inkjet printer to produce phantoms in a cheap and flexible manner. However, at the time the print quality was not sufficient to reliably produce good results. The improvement in printers and the imminent delivery of a high resolution imaging system that would require very fine detail phantoms to assess its performance mean that it is timely to reassess this technique. This work will involve the handling of unsealed radioactive material. Images will be acquired on the gamma camera and high resolution detector and analysed using existing software.

Development of an imaging device for paper chromotography (Radiation physics)

Supervisors: Ian Cullum and Jennifer Wootten

Student: UG

Radiopharmaceutical are administered to patients to allow emission (nuclear medicine) images to be taken to aid with diagnosis.Before being injected into patients, radiopharmaceuticals must undergo strict quality assurance tests to check they are safe. One of these tests is to determine if the radionuclide has been properly bonded to the pharmaceutical. This is most often performed by paper chromotography, where the different chemicals move a different distance across a paper when a solvent is applied. By determining how much activity is at each part of the paper the percentage of the radionuclide that has been properly bound to the pharmaceutical can be determined. Traditionally this has been determined by cutting the paper into sections and counting each part in a detector. Commercial systems that do not involve cutting are available but are expensive and have low sensitivity. Previous projects have determined the imaging characteristics required and possible designs for a new detector to carry out this work. In this project an instrument based on a small scintillation crystal, optical fibres and a CCD will be built and tested. Initial results will be compared with those obtained from the existing (cutting) method and the images of the strips acquired by a traditional gamma camera. The project has a very significant practical component, including: building the imaging system from existing components; testing the system; comparision of results with those from the existing technique.

Development of clinical teaching files for nuclear medicine

Supervisors: Ian Cullum and Sveto Gacinovic

Student: Rumana Lasker

The aim of this project is to develop a searchable library of nuclear medicine images for use in teaching. The library will include all types of nuclear medicine images with normal, abnormal and equivocal results. It is envisaged that the teaching files will grow as years go on so a simple and robust method of identifying he required data is needed. The teaching files will include clinical diagnosis, diagnostic scan report and relevant teaching points and will give access to important images aiding the diagnosis. The work will involve liasing with clinicians within the department to obtain the relevant information for each case and to then design the teaching pages and add the data to them. Depending on the student’s interest the project could focus more on collecting all of the relevant data (which would give a very good insight into the clinical use of nuclear medicine including attending reporting sessions with the nuclear medicine consultants) or be more concerned with the display and manipulation of the data. The teaching files themselves could range form simple screens (such as powerpoint) through to a website allowing a database of the files to be queried. There could potentially be two students involved, one with the more clinical aspects of data selection and one with the more technical aspects of implementing the filestore.

Imaging soft tissues using the vibration potential

Supervisors: Paul Beard and Edward Zhang

Student: UG

The aim of this project is to investigate whether it is possible to generate a voltage in tissue by the passage of ultrasound waves and exploit this phenomenon to image biological tissue. The method is based on the notion that a potential difference can be produced by the differential acoustically-induced motion between the charged particles and surrounding fluid in a colloidal suspension or a ionic solution. When applied to tissue imaging, the technique is most likely to be suited to imaging blood vessels. This is because blood is both colloidal (due to red blood cells) and ionic (due to dissolved  electrolytes) and should provide a relatively large signal compared to other tissue constituents such as collegen or fat. To obtain images with this approach, a focussed ultrasound beam is scanned over the sample and the induced voltage recorded at each point. The objective of the project is to design and build an experimental set-up using a focussed ultrasound transducer and sample cell equipped with a pair of electrodes to measure the vibration potential of colloidal and ionic solutions and different tissue types. A simple scanning arrangement will then be developed to obtain images of tissue mimicking phantoms and ex-vivo tissues.

Improving the resolution of radiographic images using deconvolution techniques

Supervisors: Dr. Gary Royle and Dr. Sandro Olivo

Student: UG or MSc

The spatial resolution of an x-ray image is dependent upon a number of geometric factors within the imaging system, such as x-ray spot size, imaging pixel size and the geometry of the system. In a typical imaging system these will add significant blurring to the image, making it difficult to see fine details. It is possible to reduce these effects using deconvolution techniques to try to retrieve the `true' image. This project will investigate these techniques and develop a code to try to improve the quality of x-ray images.

Development of a cone beam optical imaging system for gel dosimetry

Supervisors: Dr. Gary Royle and Dr. Jenny Griffiths

Student: Teressa Ramsay

Modern radiotherapy equipment is capable of treating complex 3D volumes within the patient. In order to verify the quality of the treatment it is necessary to check that the delivered treatment is the same as the one planned. One approach is to use a chemical gel that changes colour / opacity upon irradiation. A 3D volume within the gel can be irradiated and then compared with the treatment plan. To do this it is necessary to produce a 3D image of the gel. This project will design and build a simple optical imaging system to capture image projections of objects and reconstruct a 3D image.