Failure modes and downtime of radiotherapy linear accelerators and Multi-Leaf Collimators in Indonesia

The lack of equitable access to radiotherapy linear accelerators (LINACs) is a substantial barrier to cancer care in Low and Middle-Income Countries (LMICs). Aside from the issue of cost, there are also issues of robustness of state-of-the-art LINACs in LMICs, which are subject to mechanical and electrical breakdowns, which can result in downtimes ranging from days to months. Recent research has identified disparities in failure frequency and downtimes between LMICs (Nigeria, Botswana) and a High-Income Countries (HIC, the UK), and highlighted the need for additional data and study particularly relating to Multi-Leaf Collimators (MLCs). This study analyses data from 14 Indonesian Hospitals with a total of 19 LINACs and shows the pathways to failure of radiotherapy LINACs and frequency of breakdowns with an additional focus on the Multi-Leaf Collimator (MLC) subsystem. We found that LINACs throughout Indonesia are out of operation for 7 times longer than HICs and the Mean Time Between Failures of a LINAC in Indonesia is 341.58 Hours, or about 14 days. Furthermore, of the LINACs with an MLC fitted, $59.02^{+1.98}_{-1.61}$% of mechanical faults are due to the MLC and $57.14^{+0.78}_{-1.27}$% of cases requiring a replacement component are related to the MLC. These results outline the need to reassess the current generation of RT LINACs and ultimately work towards guiding future designs to be robust enough for all environments.