# A service evaluation of the clinical contingencies implemented during a Linac replacement programme

## TL;DR

This study evaluates how clinical contingencies during a Linac replacement program affected treatment delivery and patient outcomes.

## Contribution

This is the first service evaluation to report the practical effects of a Linac replacement program and the impact of clinical contingencies on treatment continuity.

## Key findings

- 78.5% of patients did not experience increased overall treatment time due to effective contingencies or no machine breakdowns.
- Conebeam CT faults were the main cause of machine closures, affecting breast patients more than prostate patients.
- Contingencies prevented 21.5% of patients from exceeding the 2-day extension guidance for overall treatment time.

## Abstract

A Linac Replacement Programme (LRP) was completed to ensure continuity of treatment whilst maintaining the highest standards of care. Clinical contingencies were devised to mitigate the impact of unscheduled interruptions during the LRP. This service evaluation was undertaken to appraise the effectiveness of contingencies on treatment delivery (TD) during the LRP.

The oncology management system MOSAIQ was used to generate reports of treatment adjustments. These reports were then generated for Linac service history in the 2019-2020 year for comparative analysis and causative factors in Linac breakdowns. Adjustments to treatment were analysed for each patient.

Of the 855 patients receiving treatment during the LRP, 184 were impacted in some way. Of these, 113 experienced some increase in overall treatment time (OTT); 742 (86.8%), therefore, experienced no increase in OTT, through deployment of clinical contingencies or not encountering machine breakdown during their treatment schedules. Throughout the LRP, Conebeam CT (CBCT) faults were the primary cause for machine closure. Due to this, breast patients remained on treatment at a higher rate than prostate patients who required 3D-geometric verification prior to TD.

This project highlighted the importance of preparation for CBCT faults and patient categorization in the development of contingencies. The extended dose and fractionation 60 Gy in 20# presented increased opportunities for cancellation in prostate patients, however, the use of MV imaging to assess patient set-up enabled continuation of TD. Increases in OTT could not be eliminated completely, however, for 21.5% of patients who experienced treatment adjustments the implementation of contingencies effectively prevented them exceeding Royal College of Radiologists guidance of 2-day extension in OTT.

We believe this radiographer-led project is the first service evaluation reporting the practical effects on treatment of a LRP and impact of clinical contingencies used to mitigate and limit unscheduled interruptions in treatment and minimize the extension of OTT for patients during the transition.