Radiotherapy Physics

The Radiotherapy Physics Group provides scientific expertise for the delivery of external beam radiotherapy and brachytherapy treatments. We support the current services and develop future radiotherapy techniques. At the main Clatterbridge site we currently have eight linear accelerators:

  • a new Varian Edge linac, with the Calypso tumour tracking system,
  • three Varian TrueBeam linacs, one with a PerfectPitch 6 degrees of freedom (6DoF) couch,
  • three Varian Clinac 2100Cs, two of which have the On-Board Imager (OBI) system,
  • one Varian Clinac 600C.

A second Varian Edge machine will be installed later this year. One of the TrueBeams is operated by The Clatterbridge Clinic, which is a joint partnership for the treatment of private patients.

All of our machines have multileaf collimators and amorphous silicon portal imaging. We have offered intensity-modulated radiotherapy (IMRT) treatments here since 2002, and Volumetric Modulated Arc Therapy (VMAT) has been in routine clinical use since 2008. There is a superficial unit providing X-rays from 80 kV to 140 kV and an orthovoltage unit providing X-rays up to 300 kV. We also have a 50-kV Papillon system for the local treatment of rectal cancer. Brachytherapy is carried out with a remote-afterloading high-dose-rate (HDR) microSelectron unit, as well as treatments using iodine-125 seeds and iridium-192 wire. We have two dedicated wide-bore planning CT scanners (both of which are able to perform 4D-CT scanning), and there are also two MR scanners that are used for radiotherapy planning. In addition, we have a conventional simulator with digital imaging. Treatment planning is carried out using Pinnacle, Eclipse, Oncentra and iPlan.

In 2011 we started to treat patients at our satellite radiotherapy centre, Clatterbridge Cancer Centre Liverpool, which is situated adjacent to The Walton Centre on the University Hospital Aintree site. At CCCL we have a further three Varian linacs, all with OBI and arc therapy capabilities. Two of these are Clinac iXs, while the third linac is a Novalis Tx radiosurgery system equipped with a Brainlab ExacTrac robotic 6D couch and the ExacTrac imaging system.

In common with most radiotherapy physics departments, our routine duties include:

  • Taking a leading role in the procurement of radiotherapy equipment.
  • Determining the shielding requirements when new equipment is purchased.
  • Performing quality assurance of treatment machines and treatment planning systems, at installation and regularly throughout their lifetimes.
  • Performing detailed commissioning measurements of new equipment to determine its working characteristics.
  • Establishing the framework of dosimetry for radiation therapy.
  • Providing support and scientific supervision for treatment planning, both external beam and brachytherapy.
  • Creating accurate computer models of the radiation beams for use in treatment planning.
  • Creating bespoke treatment plans for complex or unusual cases.
  • Introducing new radiotherapy planning techniques, in partnership with oncologists and planning radiographers.
  • Working closely with our clinical colleagues to introduce new treatment techniques, either as part of a clinical trial or for service development.
  • Providing physics and radiobiology advice to clinical colleagues, to aid patient treatment.
  • Providing training and education to physicists, technologists, oncologists, radiographers and nurses.

Particular interests of the Radiotherapy Physics Group at The Clatterbridge Cancer Centre include the following:

  • Stereotactic radiosurgery and radiotherapy.
  • Stereotactic Ablative Radiotherapy (SABR): hypofractionated treatments for primary lung tumours and (under the NHS England Commissioning through Evaluation programme) for oligometastases in the lung, spine, bone, lymph node, liver and adrenal gland.
  • IMRT treatments, including verification methods by measurement and by calculation.
  • VMAT treatments using both RapidArc and SmartArc.
  • Image-guided radiotherapy (IGRT), including the use of our two 6DoF couches. Gated radiotherapy treatments.
  • Interstitial and intracavitary brachytherapy using the HDR microSelectron unit.
  • Image-guided brachytherapy (IGBT) for cervical cancer, incorporating CT and MR imaging.
  • Prostate brachytherapy treatments, using the HDR unit or implanted iodine-125 seeds.
  • Multi-modality image registration for treatment planning, including MR and PET-CT image data.
  • Total skin electron radiotherapy.
  • Total body radiotherapy.
  • Contact therapy for rectal tumours using the Papillon technique.
  • Ophthalmic treatments using ruthenium-106 and strontium-90.
  • In vivo dose measurements.