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The medical physics team

Over 100 clinical scientists, clinical technologists and administrative staff are based on our two hospital sites. Many individuals within the department have national and international reputations within their field and sit on committees contributing to the development of policy, guidelines and standards relevant to their specialist areas.

Medical physics department staff also teach and train medical, nursing and other clinical staff, in addition to a range of scientific and technical staff. A number of courses are offered, for example in the safe use of ionising radiation, lasers and UV equipment.

Several of our staff hold King’s College London academic titles as a result of their research, teaching or clinical eminence.

The team

The senior staff of the department are listed below.

Professor Stephen Keevil
Head of medical physics

Stephen Keevil holds an MA in physics from Oxford University, an MSc in medical physics from Surrey University and a PhD in NMR spectroscopy from the University of London. He trained as an NHS medical physicist, followed by a series of research and academic posts in MRI physics. He joined the Trust in 2004 as head of magnetic resonance physics, and was appointed head of medical physics in 2017. He is also joint director of KiTEC (King's Technology Evaluation Centre), a NICE External Assessment Centre for medical technologies based in King’s College London.

Keevil has a particular reputation in MRI safety. He is a past chair of the Safety Study Group of the International Society for Magnetic Resonance in Medicine and has represented the MRI community in negotiations with the UK government and European Union institutions about safety and regulatory issues. Among other professional activities, he is past President of the Institute of Physics and Engineering in Medicine (IPEM), past President of the United Kingdom Radiological Congress (UKRC) and past chair of the national Clinical Imaging Board.

Sarah Allen
Head of nuclear medicine physics

Sarah has worked in as a clinical scientist in nuclear medicine for over 30 years and has a wide range of experience in all aspects of service provision. She has been head of the nuclear medicine physics team at Guy’s and St Thomas' for over 10 years and has trained and developed numerous clinical scientists, many of whom remain within the team. In addition to her role as head of nuclear medicine physics, Sarah is head of service for nuclear medicine.

Sarah is a past honorary secretary of the British Nuclear Medicine Society and is currently a trustee of the society. She has taken a leading role in the development of national guidelines and quality standards for service provision and education of the workforce within the field of nuclear medicine physics. This role gives her a unique insight into the issues that face nuclear medicine nationally as well as access to a wide range of different service models and solutions. Sarah also has experience of supporting other NHS Trusts with nuclear medicine expertise.

David Gallacher
Head of radiation safety service

David is a medical physicist with nearly 30 years of experience in radiation protection and diagnostic radiology physics. He has more than 20 years’ experience as a radiation protection adviser (RPA) and is the appointed RPA and also radioactive waste adviser (RWA) to the Trust and associated medical school. He has been involved in many major successful projects over the years developing new services for patients, including close involvement in the design of the radiation treatment and diagnostic X-ray facilities in the Guy’s Cancer Centre and working as project RPA on new clinical PET cyclotron and radiochemistry facilities on the St Thomas’ Hospital site. David is currently doing a collaborative research PhD with the University of Surrey on dispersion of radioactive gases near to buildings, arising from his RPA work with the PET Centre.  Another particular area of interest is the medical use of radiation in clinical trials, and David has been an expert member of the London Bridge Research Ethics Committee since 2011. David leads a team of expert professional scientists and technicians who are committed to ensuring the best quality, safety and effectiveness of diagnostic procedures and treatments for patients.

Dr Andrew Coleman
Head of non-ionising radiation physics

Andy has worked in the area of non-ionising radiation physics as a clinical scientist in the NHS for over 35 years. He played a leading role in developing an understanding of the mechanism of action of shock-wave lithotripsy and has published widely on ultrasound bio-effects and safety, holding numerous MRC and EPSRC grants for studies in this area. 

He has acted as research and development lead for diagnostic and therapeutic services in Guy’s and St Thomas’ and chaired the Optical Radiation Measurement Group at the National Physical Laboratory for five years. He currently serves as an expert adviser to NICE in the area of confocal microscopy in dermatology.

In 1997 Andy established the first ISO17025 accredited equipment calibration laboratory within the NHS. This lab now serves most phototherapy centres in England, including the centre at University Hospital Lewisham. He is now a consultant physicist, heading one of the UK’s largest non-ionising radiation services and also a senior lecturer at King’s College London.

Andy holds an MBA from Imperial College, specialising in health service innovation. He is an active member of the British Photodermatology Group and has many years’ practical experience of providing medical physics services to hospitals in London and the south east.

Dr Geoff Charles-Edwards
Head of magnetic resonance physics

Geoff has over 20 years of experience in MRI. He holds a PhD in MR physics from the Institute of Cancer Research and is currently an honorary senior lecturer at King’s College London. He is a past secretary of the IPEM MR SIG, and currently sits on the BIR MR SIG, the BIR MR Safety Committee and the MHRA’s Medical Device Regulation External Strategy Group. He is very active in MR teaching nationally.

Peter Cook
Chief biomedical engineer and head of clinical engineering

Peter has 10 years’ experience as a clinical engineer, now an HCPC registered clinical scientist, and four years’ prior experience in hospitals as a biomedical technician.

Peter's experience at Guy’s and St Thomas’ has included developing and implementing the Trust's medical device maintenance and training policies, including a lead role with the Trust's medical devices database used for governance of medical equipment inventory, service contracts and service records. He also has wide experience in meeting engineering standards for patient safety and regulation as well as technical support for prototype, in-house or modified medical equipment. He is the Trust MDSO (medical devices safety officer) with responsibility for dialogue with the MHRA (Medicines and Healthcare Products Regulatory Agency) and Trust's governance reporting for equipment via the medical devices management group.
In his previous experience Peter worked for two years in a hospital in Nigeria and he currently leads on equipment aspects of projects with the Trust’s link hospitals in Ndola, Zambia. Most recently this has included a two year project supporting Ndola technical staff, funded by the Tropical Health and Education Trust.

Tony Greener
Head of radiotherapy physics

Tony has over 30 years of experience in radiotherapy physics and service delivery. He currently leads a large team of physicists and dosimetrists providing a comprehensive range of physics services to the radiotherapy department. He oversaw and guided the specification, evaluation, procurement and commissioning of radiotherapy equipment for the Cancer Centres at Guy's and the satellite centre at Queen Mary’s Hospital in Sidcup.

Tony has an active interest in dosimetry and treatment accuracy within radiotherapy and has sat on national working parties involved in developing codes of practice and guidance documents in these areas.

Rashid Brora
Head of medical equipment management service

Rashid is a clinical engineer, with over 30 years of experience in the field of Medical Equipment Maintenance. Starting as a trainee, to joining Guy's and St Thomas' to head up the EME Section which is now known as MEMS. This has involved direct repair and maintenance of medical devices from nerve stimulators right through to ventilators and complex medical systems, as well as hospital wide paging systems. Experienced in developing and implementing a quality system. Some experience in development and delivery of medical equipment training for junior staff. The MEMS section supports in excess of 30,000 medical devices, both service, repair and advice on selection providing some support for other organisations. Also providing some user training in the operation of medical devices.  

Rashid also leads the Trust’s medical equipment library that supports all wards with a variety of generally used devices, from nebulisers, fall monitors, infusion pumps both volumetric and syringe pumps, wound healing pumps to patient monitors. 

Winston Swaby
Head of radiation equipment servicing

Winston has been maintaining and servicing linear accelerators for over 25 years. Prior to joining the Trust, 12 years ago, Winston had been working with the manufacturers of linear accelerators to install, maintain and troubleshoot these devices in various hospitals around the world.

Qualified with a BSc in electrical and electronics Winston has worked in numerous medical equipment departments and now heads the radiotherapy equipment service team at Guy's and St Thomas'. This team is dedicated to the maintenance and servicing of radiotherapy equipment in the Trust.

Mark Stanton
Head of mechanical workshop

With nearly 35 years’ experience in general engineering and over 15 years’ experience working as a medical engineer; Mark has been the head of the mechanical workshop since June 2017. Mark has completed a higher national certificate in mechanical engineering. He started in engineering by completing a four year toolmaking apprenticeship learning how to make high precision plastic injection and zinc alloy die-casting moulds.

In his time at Guy's and St Thomas' he has completed numerous design and construction projects for the Trust. He also worked with the workshop team to achieve accreditation to BSI ISO 13485 for the design, manufacture, repair and maintenance of medical equipment.