91̽»¨

Abstract:

Resonance crossing during beam acceleration in a Non-Scaling FFAG could cause beam blow-up when the acceleration rate is slow. This could potentially constraint the lattice design of proton NS-FFAG. Therefore, an understanding of the beam dynamics of resonance crossing acceleration is crucially important to establish the design strategy of proton NS-FFAG. This paper describes the beam blowup process of an NS-FFAG and discuss the blow-up rate quantitatively.

Abstract:

The lack of radiotherapy linear accelerators (LINACs) in Low- and Middle-Income countries (LMICs) has been recognised as a major barrier to providing quality cancer care in these regions, along with a shortfall in the number of highly qualified personnel. It is expected that additional challenges will be faced in operating precise, high tech radiotherapy equipment in these environments, and anecdotal evidence suggests that LINACs have greater downtime and higher failure rates of components than their counterparts in High-Income Countries. To guide future developments such as the design of a LINAC tailored for use in LMIC environments, it is important to take a data-driven approach to any re-engineering of the technology. However, no detailed statistical data on LINAC downtime and failure modes has been previously collected or presented in the literature. This work presents the first known comparative analysis of failure modes and downtime of current generation LINACs in radiotherapy centres in 91̽»¨ (UK), Abuja, Enugu, Lagos, Benin (Nigeria) and Gaborone (Botswana). By deconstructing the LINAC into 12 different subsystems, it is shown that the failure rate in an LMIC environment compared to the High Income Country (HIC) is more than twice as large in 7 of the 12 subsystems. The results of this study inform future attempts to mitigate the problems affecting LINACs in LMIC environments.