MPHY3000/MPHYM000: Medical Physics Projects 2010/11

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 18, 2010. 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 17, 2011.
  • Project talks will be held on Wednesday March 16, 2011 in Room 2.14 of the Malet Place Engineering Building.
  • Final Reports are due by Friday March 25, 2011. Please hand in to the Medical Physics Departmental Office (second floor of the Malet Place Engineering Building).

Project information

Texture analysis of prostate MR images - can it improve localisation of tumour?

Supervisors: Dr. Shonit Punwani and Dr. David Atkinson

Student: Taiki Fujiwara

Conventional detection of prostate cancer involves prostate specific antigen measurement followed by random biopsy performed using transrectal ultrasound. MRI is used for staging local and distal disease after tumour has been histologically confirmed. Recently MRI performed prior to biopsy has shown encouraging results in localising disease prior to biopsy and therefore may be of use in guiding or even replacing biopsy. However at present when clinically reported there are still a large number of equivocal MR studies - almost 50% - that necessitate biopsy to elucidate findings. Interpretative difficulties occur predominantly in the transition zone where adenomata and tumour are difficult to distinguish, and in the peripheral zone in the presence of inflammatory change which can mask disease. This project aims to determine whether texture analysis techniques applied to prostate MR images are able to aid tumour localisation when current radiological reporting fails. We have acquired a large number of prostate MR datasets with matched histology on which the student can apply current, and if able, develop new texture analysis techniques. It is expected that the student will be jointly supervised by Dr David Atkinson (Centre for Medical Image Computing) who will assist with development and application of the texture analysis algorithms, and Dr. Shonit Punwani (Clinical Radiologist at UCLH) who will supervise the clinical evaluation of the developed techniques.

Measuring changes in the left prefrontal cortex haemodynamics during brain training using near infrared spectroscopy

Supervisors: Prof. Clare Elwell and Dr. Christina Kolyva

Student: Peter Legg

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Action potential duration and conduction velocity interactions at the sites of RVOT ectopy initiation and ablation: an in-vivo human mapping study

Supervisors: Dr. Malcolm Finlay and Prof. Nick Donaldson

Student: Hannah Marber

Right Ventricular Outflow Tract (RVOT) tachycardia and ectopy are an important cause of morbidity in patients with otherwise normal hearts. They both describe a condition where premature electrical activation of the heart is caused by depolarisation waves initiated in the right ventricle rather than the usual pacemaker in the right atrium. The cause of this abnormal activity is incompletely understood but it can be successfully cured by destroying the responsible heart tissue. This procedure is known as catheter ablation and involves the geographically precise delivery of a radiofrequency pulse to destroy cardiac myocytes. Thus, the precise anatomical site responsible for the initiation of the premature electrical depolarisation wave has to be identified. Unfortunately, this focal source can be difficult to locate with standard techniques. This difficulty results in part from the fact that after its initiation, the depolarisation wavefront travels a short distance through a localised intramyocardial pathway before emerging as a generalised wavefront of depolarisation that activates the heart abnormally and gives rise to the ectopic beat/tachycardia that can be seen on the surface electrogram (ECG). Thus, since the short intramyocardial pathway is not visible on the surface ECG it can only be mapped using intracardiac electrodes. Currently such mapping is difficult since one first needs to identify the precise exit point in order to trace the short path to the point of initiation. A better understanding of how the local anatomical site of exit of the tachycardia can alter the morphology of the surface electrocardiogram (ECG) would greatly aid, spatially targeted intracardiac interrogation and thereby the understanding, and ultimately the treatment, of this debilitating condition. The student will become familiar with the technique of vector-based ECG analysis. The digital capture and averaging of ECG waveforms recorded from different points in the body will be used to demarcate the anatomical site of earliest activation based on standard models which will be used to investigate the electrical properties of the Right Ventricle and relate this to patient specific data derived from MRI images and intracardiac electrograms recorded at standard anatomical landmarks . Additional data will be acquired from the same patients following treatment. The student will also be expected to analyse retrospective data to inform prospective data gathering. The student will have the opportunity to learn the principals of digitisation of complex analogue signals and their analysis within the MATLAB environment. They will also gain brief exposure to the routine clinical electrophysiological data collection and analysis currently available within the off-the–shelf commercial catheter lab electrophysiology packages. It is envisaged that this work will at least lead to an abstract submission and perhaps to a peer-reviewed publication dependent on the ability of the surface ECG to predict the exit site of the depolarisation wavefront. The clinical portions of this work will be supervised by Dr. Pier Lambiase (Senior Lecturer and Consultant Cardiologist) and Dr. Malcolm Finlay (SpR/Clinical Research Fellow). The signal processing and analysis will be done in collaboration with Dr. Ben Hanson (Lecturer in Biomedical Engineering).

A phantom for proton radiography

Supervisors: Dr. Gary Royle and Edgar Gelover Reyes

Student: Stephanie Chamary

Proton therapy is a highly advanced form of radiotherapy treatment which can deliver a conformal radiation dose to the tumour site much more accurately than conventional radiotherapy. It has proven to be very successful in treating difficult tumours close to critical organs and paediatric cancers. The better conformality of the treatment site means that it is even more important to be able to accurately localize the tumour volume within the patient. A system for proton radiography is currently being developed which aims to image the patient with the proton beam immediately prior to treatment to ensure they are correctly positioned. This project will involve learning about proton therapy and proton radiography, performing some computer simulations of a proton treatment and developing test objects that we can use to evaluate the performance of the proton radiography technique.

A 3D optical scanner for radiotherapy dose mapping

Supervisors: Dr. Gary Royle and Dr.Jenny Griffiths

Student: Thomas Millard

Modern radiotherapy equipment is capable of delivering very complex 3D radiation dose volumes to patients to match the shape of the region to be treated. It is important to be able to check that the equipment is delivering the dose exactly in accordance with the planned treatment. 3D imaging detectors exist on a small scale but current technology prevents patient size systems. Dosimetry gels exist that can change its chemical properties according to the amount of radiation dose it receives. Certain gels can change colour or opacity. The aim of this project is to develop a simple tomographic optical scanner that can image the gel and produce a 3D map of the opaque region, thereby producing a 3D dose map. This project will involve learning about modern radiotherapy treatments and computerized tomography techniques, optimizing optical scanning equipment, and producing 3D images of test objects.

Image correction procedures for diffraction CT

Supervisors: Dr. Gary Royle and Kate Pepper

Student: Thurston North

X-ray diffraction is a technique which has long been used to identify the internal composition of an object. The group at UCL has applied x-ray diffraction analysis methods to investigate disease states of biological samples. A system has been built which can produce high resolution 2D and 3D images of such samples. The system is ultimately to be used to locate and identify cancerous cells within a tissue sample. This project will involve learning about x-ray imaging and x-ray diffraction analysis, obtaining some images of test objects using the system and implementing algorithms to improve the quality of the images produced in order to correct for the various interactions in the sample.

Accuracy, stability and efficiency of numerical models of ultrasound wave propagation

Supervisors: Dr. Ben Cox and Dr. Brad Treeby

Student: (Project available)

‘k-Wave’ is a free Matlab toolbox for simulating acoustic wavefields based on a pseudospectral k-space method. It is popular (it has been downloaded over 400 times so far this year) but several aspects relating to its accuracy, stability and efficiency remain unexplored. For instance, for a homogeneous medium the solution will be exact for timesteps of any duration. For a heterogeneous medium this is no longer true, but how long can the timestep be before the error in the solution (a) becomes too large, or (b) grows without limit (ie becomes unstable)? How does this depend on the nature of the heterogeneity, eg, its smoothness or size? Could an implicit implementation of the code, rather than its current explicit form, be developed? Would this improve the stability? Would this introduce excessive numerical absorption? This project will consist of computer-based numerical experiments typically making rigorous comparisons between numerical computations and analytical solutions. The first part of this project will consist of rewriting the Matlab code to work on Octave, the free Matlab clone, so will require some knowledge of using and programming in Matlab. It will suit a student who is strong mathematically and is interested in computer simulation.

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

Supervisors: Dr. Alessandro Olivo and Dr. Konstantin Ignatyev

Student: Surrin Deen

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.

Wave and ray-optics approaches to x-ray phase contrast imaging

Supervisors: Dr. Alessandro Olivo and Dr. Peter Munro

Student: (Project available)

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. There are two basic ways of describing x-ray phase contrast imaging theoretically: one is rather rigorous and is based on Fresnel/Kirchoff diffraction integrals, whereas ray-optics offer a substantially simplified approach. The phase contrast group at UCL has developed software to simulate phase contrast images following both approaches. The student will be provided with this software and will use it to investigate under what set of conditions ray optics can be considered a satisfying approximation. The student will gain skills in simulation methods, data analysis, image analysis and familiarize with the basic concepts of optics. Computing skills and a reasonably sound mathematical background are required.

Effect of the number of projections on CT reconstructions

Supervisors: Dr. Konstantin Ignatyev and Dr. Alessandro Olivo

Student: Cathal O'Brien

Computed Tomography (CT) is a non-destructive tool that allows obtaining three-dimensional information about the inner structure and composition of the objects. It is routinely used in medicine (CAT-scan), biological, material science and industrial applications. It works by recording X-ray projections of the sample at several angles, and using specialised algorithms to reconstruct the object in 3D. The goal of the project is to familiarise a student with the principles of CT, including mathematics behind it. For many CT applications it is ineffective or impossible to collect the complete dataset required for the exact reconstruction. The student will investigate the effect of limited number of angles and/or magnification and source size on the quality of the reconstruction. It will include writing software using student’s choice of programming language to do CT reconstruction using software model and use existing software for 3D visualisation of it. The effect of different experimental parameters can be studied using the computer model. At the end of the project a student will have a chance to build a basic CT set in the Radiation Physics Lab, collect a dataset, reconstruct and visualise in 3D the object of his choice. Basic computing skills are required.

An investigation of the statistical nature of image contrast in coded aperture phase contrast imaging systems

Supervisors: Dr. Peter Munro and Dr. Alessandro Olivo

Student: (Project available)

X-ray phase contrast imaging has the potential to effect the greatest change in the field of x-ray imaging since the invention of computed tomography. The majority of x-ray imaging systems employed in real world applications are sensitive to spatial variation of a sample's x-ray absorption characteristics. Most typical samples which need to be imaged by x-rays also exhibit spatial variation in the way the sample retards x-rays, generally resulting in the refraction of x-rays. Until recently, this effect could be observed only at Synchrotrons or with specialised laboratory sources with insufficient flux to be used in most real world applications. The radiation physics group within the department has, however, been developing a technique capable of observing x-ray phase contrast with standard x-ray sources. This technique is called coded aperture x-ray phase contrast imaging (CAXPCI). One of the attributes of this system is that the measured contrast depends upon where a sample is positioned relative to the imaging system. The imaging system thus has regions within its field of view which are more sensitive than others. The aim of this project is to obtain a statistical description of the contrast improvement which may be expected from the CAXPCI system when imaging cylindrical fibres. The project will entail understanding how the CAXPCI system is modelled. You will use a model which has already been developed to generate results according to a methodology which you will develop to determine the statistical nature of the contrast improvement offered by the CAXPCI system. It is also hoped that additional characteristics of the system, such as quantifying how different regions of the system's field of view differ in sensitivity, will be ascertained. An understanding of wave optics and scalar diffraction will be required for this project along with a good ability to program in Matlab.

A fluorescence spectrometry system for pharmacokinetics

Supervisors: Dr. Sandy Mosse and Dr. Nick Everdell

Student: Prakash Jeganathan

Our group is involved with the development and clinical testing of drugs used for photodynamic therapy (PDT). In PDT the patient is given a drug that makes them sensitive to light and then intense light is shone into the tumour or other tissues to be treated. A problem is that while the drug is present in the skin, the patient is light sensitive and has to stay in subdued light, so it is highly desirable to monitor the rate of drug clearance from the skin. One method for doing this is to measure the intensity of the fluorescence of the drug in the skin and our group have two systems developed by groups elsewhere to detect fluorescence. Unfortunately, deficiencies have been identified in both systems and we therefore propose to build our own. The project is to help design and build such a system and should be attractive to a student who enjoys making things; it will involve some optics and electronics though, both at a simple enough level that prior experience is not essential.

Electrical Impedance Tomography (EIT) of epileptic activity

Supervisors: Prof. David Holder and Dr. Dominic Heaney

Student: (Project available)

EIT is a novel medical imaging method, with which images of the electrical impedance of the head can be produced with a box about the size of a paperback book, laptop  and EEG electrodes on the head.  It is portable, safe, fast and inexpensive.  The supervisor’s research has been to develop its use in imaging functional activity in the brain. One exciting application lies in its use to image changes in the brain due to epileptic activity. In epilepsy, abnormal activity may occur in the form of seizures in which there is continuous abnormal activity lasting a minute or so.  There is also “interictal” activity, in which there is non-seizure epileptic activity which lasts for a second or so and is not noticed by the patient.  This is associated with a small local increase in blood flow which can be detected with functional FMRI sin some subjects. It could also be detected with EIT and this is the topic of this project. Using software already developed, the purpose of the work will be to record EIT and EEG at the same time in patients brought into hospital for evaluation of their epilepsy. The recordings will be over several hours. Using the developed software, all examples of interictal epileptic activity will be marked on the EEG. All the current sections of EIT will be averaged together and used to reconstruct an image of the associated change in blood flow. The signal to noise ratio in such recordings is low; the hope is that averaging of many examples will lead to accurate images. If successful, this would provide a new method for diagnosis in epilepsy. Students will work together to collect EIT data during repeated evoked activity in about 10 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. Skills to be acquired: Students will spend time in the lab in Medical Physics at UCL learning relevant methods and analysing the data, and some time in Prof Holder’s department at UCH, learning how to collect evoked responses using scalp electrodes. Skills to be acquired will include one or more of: medical image reconstruction; photogrammetric software use; medical image segmentation and meshing software; EEG electrode placement and use; experimental design and data analysis. The project would be suitable for a single student or more than one working in a team, with a background in medical physics, engineering, computing, or medicine.

A new method for diagnosing muscle disease with bioimpedance measurement

Supervisors: Prof. David Holder and Dr. O. Gilad.

Student: (Project available)

At present, electrophysiological diagnosis of different muscle diseases in undertaken with needle recording of the electrophysiological signals – this is termed “Electromyography” (EMG). The idea behind this project is to make recordings of electrical impedance to aid in this diagnosis. The work will be to review relevant literature concerning muscle impedance studies, and test electrical impedance measuring equipment in the laboratory for this purpose. If successful, this will then be tested in a small number of patients with muscle disease. Students will spend time in the lab in Medical Physics at UCL learning relevant methods and analysing the data, and some time in Prof Holder’s department at UCH, acquiring muscle impedance data. Skills to be acquired will include one or more of: biomedical instrument use and assessment, EMG, biophysical modelling. experimental design and data analysis. The project would be suitable for a single student or more than one working in a team, with a background in medical physics, engineering, or medicine.

Electrical Impedance Tomography (EIT) of evoked physiological activity

Supervisors: Prof. David Holder and ???

Student: (Project available)

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

Assessment of a novel method for automated EEG analysis

Supervisors: Prof. David Holder and Dr. Tom Tidswell

Student: (Project available)

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. Students 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: Matlab programming; simple medical statistical analysis; EEG use; experimental design and data analysis. The project would suit students with a background in medical physics, engineering, computing, or medicine. Some experience in programming, ideally with Matlab, would be desirable.

Optical monitoring of High Intensity Focused Ultrasound (HIFU) treatment

Supervisors: Dr. Terence Leung and Prof. Jem Hebden

Student: Yee-Teng Chon

High Intensity Focused Ultrasound (HIFU) is a minimally invasive therapetic technique which exploits focused ultrasound to heat up and destroy tumour remotely. We are currently investigating the use of a technique known as ultrasound-modulated optics (UO) 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) making novel tissue-mimicking phantoms with regions containing thermochromic pigment which changes colour as its temperature rises, and (2) performing UO measurements on the phantoms. This project is best suited to a student who enjoys building models and performing scientific measurements.

Exploring the optical measurements of brain tissue oxygenation and metabolism during a CO2 challenge in healthy adults, with the aid of a computational model

Supervisors: Dr. Ilias Tachtsidis and Tracy Moroz

Student: Timothy Easton

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 reach the brain tissue; from the detected reflected light we can resolve measurements of oxygenation and metabolism. To help enhance our understanding of our measurements and the brain physiology we have developed a computational physiological model of brain circulation and metabolism. The model predicts several physiological variables, including those which can be measured with NIRS. We have recently completed a large study on healthy young volunteers where we induced changes to the level of carbon dioxide (CO2) in their breathing gases. Changes in CO2 levels are known to alter brain blood flow and maybe metabolism. The aim of this project is for the student to use our computational model to perform simulations and reproduce the experimental results as closely as possible with the model, and in doing so, enhance our understanding of the measurements, and the underlying mechanisms of the CO2 challenge. This project would be suitable for students with an interest in human physiology and will involve data processing and some statistical analysis.

Designing and constructing a tissue-like infant head phantom for evaluating simultaneous EEG and optical imaging

Supervisors: Prof. Jem Hebden and Joanna Brunker

Student: Michael Whitewood

Researchers within the UCL Biomedical Optics Research Laboratory (BORL) have developed a technique 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 aim of this project is to develop a suitable “phantom” which can be used to test the imaging system. A phantom is an object which simulates the properties of real human tissues. The project will initially involve designing and building a hollow infant head based on polyester resin. Thin conducting wires will be embedded within the resin so that both light and electrical currents can pass through the head. The head will then be filled with an optically-scattering / electrically-conducting liquid. Measurements will be made using optical fibres and electrodes placed on the surface of the head with a suitable target placed inside. 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 tissue-equivalent phantom for optical imaging of the brain, with a realistic infant head geometry

Supervisors: Prof. Jem Hebden and Dr. Nick Everdell

Student: Alex Goodall

Optical imaging techniques are being developed at UCL as a means of imaging blood flow and oxygenation changes in the outer (cortical) regions of brain in response to certain stimuli and mental processing. Testing and evaluation of these optical methods and devices requires suitable objects with tissue-like optical properties, called phantoms. The aim of this project is to develop a phantom which mimics the geometry of the newborn infant head. First, moulding and casting techniques will be used to construct a phantom made from polyester resin mixed with suitable scattering and absorbing substances. Discrete targets, containing a thermochromic pigment, will be embedded within the phantom which change their absorbing properties when heated. Second, imaging experiments will be performed to verify the effectiveness of the phantom, using a so-called optical topography system developed at UCL. Further details about the imaging system can be found here. This project is most suitable for a student who enjoys building mechanical and/or electrical devices and has good manual skills.

Understanding the effect of surface roughness on electrode impedance

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: Robin Gammon

A polarisable electrode like platinum has an impedance that has both capacitance and resistance but these are not combined in a simple way. 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. In this project, the effect of different types of roughness will be explored using models made from resistors and capacitors in 2D arrays. The impedance of these models will be measured on an Impedance Analyser. An enjoyment of model-making and mathematics will be helpful in this project. Topics: electrode impedance, impedance of networks.

Wind Turbines in the Jet Stream: a feasibility study

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: (Project available)

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. Topics: aerodynamics, turbines, energy generation, meteorology, investment.

Is there a vegetal analog to the Action Potential?

Supervisors: Dr. Anne Vanhoest and Prof. Nick Donaldson

Student: Jason Yeung

The electrical activity of selected plants will be studied in response to various stimuli (touch, light, heat, electricity). The student is asked to establish whether this vegetal activity is analog to an Action Potential and could be used in demonstrations where ex-vivo animal nerves would otherwise be required. This is a lab-based project, the student will be taught how to use stimulation and recording equipment and is expected to be "hands on" and practical. There will also be a preliminary literature review based on Fromm and Lautner (Plant, Cell and Environment, 2007). Topics: basic nerve physiology, electrical stimulation, lab practice, literature review

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 take place in the lab, characterizing existing sensor candidates and researching other materials, suitable in terms of their bio-compatibility and sensing properties. If the progress are satisfactory and the student shows good lab behaviour a second stage will involve the production of new sensors in the cleanroom. Topics: humidity sensor, electronics, thick-film printing, material science

History of Electrotherapy

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: Sahra Haji

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.

Portable Impedance Analyser

Supervisors: Prof. Nick Donaldson and Dr. Anne Vanhoest

Student: Framroze Elavia

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.

Electrolytic Pump

Supervisors: Prof. Nick Donaldson and Nathaniel Dahan

Student: Devinder Kaur

Heart pacemakers were the first successful neuroprosthesis and the way their electronics is protected from body fluid is orthodox for implanted devices. They use a titanium case that has a metal-in-glass feed-through for the connection to the electrode, and the case is closed by welding. This construction is expensive and simpler methods might reduce the costs of implanted devices. One possibility is to use a plastic enclosure, through which water will diffuse, but pump the water out by converting the liquid water, condensed in a salt-filled sponge, into gas by electrolysis. The gas would escape through a pressure-relief valve. The project will be to test this idea by experimenting with chambers which include a humidity sensor and tests are done with various salts, electrodes and drive voltages. The aim will be to show that the relative humidity can be maintained at a level significantly below 100%. Topics: electrolysis, relative humidity, properties of salts.

Characterisation of the Breastlight breast cancer detection device

Supervisors: Dr. Adam Gibson and Dr. Louise Enfield

Student: Eoin Dore

Breastlight is a device that transilluminates the breast with a red light. It is designed for women to use at home as part of their breast awareness programme. Areas where there are extra blood vessels, such as tumours, appear darker than healthy areas. In this project, we will design and build test phantoms which will allow us to characterise the spatial resolution, contrast, sensitivity and specificity of the device.

Implementation of de-blurring routines

Supervisors: Dr. Caroline Reid and Prof. Robert Speller

Student: (Project available).

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.

Intelligent CT

Supervisors: Prof. Robert Speller and Dr. Peter Munro

Student: (Project available).

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: Joseph Borucki

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: Jessica Smith

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.

Porosimetry of absorbent materials

Supervisors: Prof. Alan Cottenden and ????

Student: (Project still available).

Porosimetry involves measuring the capillary pressure of porous materials as a function of their saturation and, theoretically, data should correlate with the wicking and fluid retention properties of the materials. This project will test this theoretical prediction by conducting careful porosimetry, wicking and retention measurements on some absorbent fabrics used in medical devices. The results will help us with our ongoing efforts to understand the fluid handling properties of existing materials and develop better ones. The project will be primarily experimental and based at the UCL Archway campus (by Archway tube station).

How does the fibre footprint of a fabric on a surface depend on the stiffness of the surface?

Supervisors: Prof. Alan Cottenden and ????

Student: (Project still available).

As part of our work to reduce the impact of incontinence pads on the skin of their wearers, we have recently developed an optical microscopy technique for visualising and quantifying the fibre footprint of nonwoven fabrics of the kind used to face incontinence pads on skin surrogate materials. An associated mathematical model predicts that – up to a point - the footprint should be the same for compliant materials (like real skin) and stiffer materials (like glass). If proved to be true, this would be very helpful as it is much easier to make measurements on glass. The purpose of this project will be to test this prediction by measuring the footprint of a sample fabric against glass and against various silicone rubber skin surrogates under a range of loads and comparing the data. The project will be primarily experimental and 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: Yiakovos Nicolaou

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).

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

Supervisors: Prof. Alan Cottenden and ????

Student: Nasik Ahmad

Description: 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 primarily experimental and based at the UCL Archway campus (by Archway tube station).

Dose optimisation in lateral cephalometry

Supervisors: Dr Adam Gibson and Dr Jenny Griffiths

Student: Roman Hochuli

A standard imaging protocol in orthodontics is to take a lateral x-ray image of the head. From this image, certain landmarks are identified and some standardised measurements are made. This allows facial deformities to be identified and characterised as well as informing the surgical treatment. The patients are usually children and we want to reduce the radiation dose.

In this project, you will simulate the effect of reducing the radiation dose and examine the effect of dose reduction on image quality. You should be able to recommend a new protocol and predict the subsequent dose reduction.

This project will be carried out in collaboration with Kidderminster Hospital and you may be expected to travel there on occasion; expenses will be covered.