A modular, integrated electron gun and RF cavity for radiotherapy treatment systems in developing countries

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4 in 10 patients with cancer in the UK receive radiotherapy treatment on a linear electron accelerator (linac) based radiotherapy treatment (RTT) system. In the lowest income counties within Africa only 4% of cancer patients that need radiotherapy receive RTT . There are currently 385 radiotherapy machines on the continent of 54 countries and 1 billion people. About 60% of the machines are found in just three countries: South Africa, Egypt and Morocco. The next 20% are also in just three countries: Tunisia, Nigeria and Algeria. Figure 1 shows the number of RTT machines per million people , as can be seen in Europe almost all counties have more than 1 machine for every 0.2 million people while in Africa many countries have less than 1 machine per 5 million people. Even though high cost of these machines is an issue, downtime is a major issue in African radiotherapy centres which can affect treatment outcomes and severely limits the number of RTT facilities. In 2016 Ghana's only RTT failed, having been in operation since 1995, while most RTT machines are only meant to last 10-15 years with proper maintenance by the manufacturer. In this project we aim to optimise a radiotherapy system to make maintenance easier while extending the life of an RTT system. One of the most common parts to fail is the electron source (gun) of the linear accelerator which can have a lifetime of 2-3 years . Typically, the electron gun is an integrated part of the linac, and in case of fault all of the linac needs to be replaced or returned to the manufacturer for repair which is expensive and takes a long time. Our aim is to make a modular electron gun that can be repaired seperately from the linear accelerator. We will also look at reducing the cost of the RF cavity and minimising beam losses inside the cavity to help reduce the cost as well.