Radiotherapy physics - overview

The Radiotherapy Physics Group provides scientific, technical and training support to the Radiotherapy department at The Christie.

Our aim is to enable the safe and accurate delivery of radiotherapy.  In addition it is a lead contributor to major research and development programme's and has a number of teaching commitments. 

The group is divided into a number of sections mainly for the purpose of managing the routines services provided by these sections. However there are many projects and development work carried out by individuals and teams that cross the boundaries of the sections and utilise the skills of the different professional groups.

The following services are offered:

  • Dosimetry
  • Treatment planning
  • Brachytherapy
  • Radiotherapy Technical Services Group (RTSG)

Dosimetry is the monitoring of the quality and measurement of dose of radiation output from radiotherapy equipment.

The roles of the dosimetry section are:

  • To ensure that all external beam treatment units (Linear accelerators) are calibrated to give the correct dose. This calibration is traceable to the National Physics Laboratories primary standard. 
  • To assure quality of the x-ray and electron beam output by means of regular quality control checks
  • To measure x-ray and electron dose data required for planning patients treatment. This includes data provided in the quality system for manual planning of patient’s radiotherapy and the checking of patient treatments planned on the computer. Large amounts of data are also required to allow treatment planning computers to calculate complex treatments accurately.
  • To perform verification measurements of treatment plans. This may be done indirectly by measurement of similar dose distributions in phantoms or directly using in-vivo dosimetry techniques. 

Radiotherapy planning is the process of how the specialist oncology team (consisting of clinical oncologists, therapy radiographers, dosimetrists and medical physicists) determine how best to treat the patient’s cancer using multiple “beams” of x-rays.  Powerful computers are used that have the ability to calculate, analyse and optimise how radiation dose is deposited in the body. 

The roles of the treatment planning section are:

  • To plan radiotherapy using advanced techniques where appropriate Examples are: IMRT, VMAT, SABR (link to treatments we offer).
  • To ensure all patient plans are carefully checked by an independent person.
  • To develop and advance radiotherapy planning techniques to meet the needs of patients, led by technical innovation and new equipment, as part of the specialist oncology team. 
  • To collect “beam” data from the linear accelerators and ensure it is correctly entered into the planning system to enable dose calculations to be correctly performed.
  • To ensure that the treatment planning computer system is commissioned to enable safe and accurate plans

The planning process:

There are several steps to the planning process which have to be carefully scheduled and timed around the consultant oncologist’s availability and the patient’s start date.  The process is roughly as follows:

  1. Once the patient has attended for the planning scan, the CT images acquired are loaded onto the planning system.  They are carefully checked to make sure that the images are adequate for the planning process to be safely completed. 
  2. The clinician defines where they want the radiotherapy to be focussed and where appropriate, a discussion occurs about what sensitive tissues need to be avoided and what techniques to utilise.  Any previous radiotherapy or other important factors are taken into account.
  3. The plan is created; most patients will follow a written protocol or pathway within our quality system so that all patients are planned to the same safe standards. 
  4. The plan is independently checked for errors, by both a computer programme and an experienced staff member and often delivered to a phantom patient so that we can check that the transfer process is correct.  Once these checks are complete, the plan is handed to the radiotherapy department for them to prepare for treatment delivery.

Treatment offered

Brachytherapy is the use of radioactive sources to treat cancer.  The radioactive source(s) are placed on or in the cancerous tissue to enable the treatment to be delivered directly to the tumour. This has the advantage of enabling large doses to be given whilst minimising side effects. 

The roles of the Brachytherapy section are:

  • Functioning as a multidisciplinary department where physicists, radiographers and the clinical team work closely together to treat patients.
  • Effectively treating a wide range of treatment sites including high and low grade prostate cancer, vaginal, endometrial and cervical cancer, skin cancers and lung cancer.
  • Responsible for ensuring the safe delivery of treatments using radioactive sources.
  • Ensuring patient treatments are individually planned and independently checked by registered physicists and radiographers.
  • Ensuring that all appropriate staff are trained in the safe use of radioactive sources and the associated radiation protection procedures.
  • Development of new state of the art techniques and improvements to current treatments.

The role of the RTSG is the provision of the daily engineering service requirements to the Departments of Radiation Oncology, and Radiology. RTSG ensure delivery of the highest quality clinical services, ensuring that equipment downtime is kept to a minimum and departmental disruption is avoided.

The roles of the RTSG section are:

  • Provide scheduled preventative maintenance to the hospital's Radiation Oncology, Radiology and Brachytherapy equipment as determined by the preventative maintenance schedules developed in house and as recommended by the equipment manufacturer.
  • Provide a fast and efficient response in the event of equipment breakdown.
  • To ensure that all external beam treatment units (Linear accelerators) are calibrated to give the correct dose. This calibration is traceable to the National Physics Laboratories primary standard. 
  • To assure quality of the x-ray and electron beam output by means of regular quality control checks.
  • To liaise with manufactures and clinicians during the procurement of new equipment.

  • MR linac
  • Protons (link to proton pages)
  • Adaptive radiotherapy
  • SABR

Staff of all disciplines conduct research and development as part of their roles working across all the sections to enable patients to benefit from evolving technology. 

Additionally, we have close links with the University of Manchester with staff having academic posts in conjunction with their clinical roles or contributing to teaching and training either academically or on the job.

Here are some examples of the teaching activities all our staff groups are involved in.

  • Lecturing on Undergraduate and Postgraduate courses at Manchester University
  • The section is an IPEM approved training centre for clinical scientists and technologists
  • Radiotherapy radiography students and staff.
  • Training of Clinical Engineers in Radiotherapy
  • Providing specialist training. Current courses being offered can be found here

Staff actively participate in a range of professional matters ranging from advising on national training requirements, refereeing scientific papers to providing scientific and technical advice to national and international bodies.

Quality System

  • The group operates within BS EN ISO 9001:2000 quality system. 

Group leader

  • Dr J-C Handley

Main contact

For more information please contact:

These are some websites that might be of interest.

Institutes and Professional bodies


(Link to each profession)

  • Dosimetrists
  • Radiotherapy physicists
  • Radiographers

Last updated: April 2024