High Reliability, Modular Radiotherapy Treatment Linac for cancer care in Developing Countries

Currently Africa has less than 10% of the required capacity to deliver radiotherapy to cancer patients. The participants in this project are working with UK and global collaborators, such as CERN and the International Cancer Expert Corps (ICEC), to develop medical linac solutions in challenging environments in Africa. The key factors to address are the lifetime, service and repair of components in the linac of the radiotherapy system. This project aims to address these factors by making changes to the design in addition to implement the modular design approach.
During a previous project we investigated the use of RF pulse modulated gridded guns to inject bunches of electron beams into the RF structure to increase capture. The results of the project demonstrated that it's possible to provide almost 100% capture and deliver the beam with a very narrow energy spread (typical radiotherapy systems are only able to capture 50% of the beam). However recent studies have suggested the use of the grid reduces the cathode lifetime by a factor of three. The studies also demonstrated that the linac efficiency can be improved by operating first cell of linac at lower gradient enabling 90% capture, with only 25% of electrons in the low energy tail using convenient DC pulse modulated guns. We believe that this effect is due to velocity bunching and request funds to further study this to attempt to reach 100% capture with no electrons in the tail. Such an approach could allow very long lifetimes with little maintenance. Modular design will improve the capability to repair when the system does fail.

The main aim of this project is to create a linac optimised for use in Africa for widening access to radiotherapy machines. As mentioned previously Africa has only 10% of the required radiotherapy capacity with many machines currently not in use due to failure or missing parts.
This project is also highly relevant to security linacs where maintenance is also a major issue. The collaborators are in discussion with Rapiscan about application in cargo scanning.
The next step after this project would be to construct a prototype including the rotating gantry, collimators and CT systems. Several routes to impact are being considered at present, with ICEC preferring the creation of a separate spin-out company and CERN preferring to provide royalty-free licences to existing vendors. The radiotherapy machine contains more than just the linac hence the route will be decided by the overall collaboration. ICEC is embedded in radiotherapy centres in most LMICs, aiming to improve access through staff training, mentoring and technology development and hence are ideal partners to take this forward to market.