ESTRO 2024 - Abstract Book

S5870

RTT - Service evaluation, quality assurance and risk management

ESTRO 2024

Attention is paid in our HyperArc simulation (slice thickness of 1 mm) procedure to not collect more than 350 slices, in order to meet the 1.0 mm tolerance recommended by the AAPM-Task Group 42. This restriction implies a longitudinal field of view of 35 cm of the CT simulation, which is enough to include the patient's shoulders for the majority of cases.

Keywords: HyperArc, CBCT, Winston-Lutz

386

Poster Discussion

Reducing CT rescans through the introduction of pelvic mini-scans

Carla O'Connell, Eoin McGrath

Cork University Hospital, CUH/UCC Cancer Centre, Cork, Ireland

Purpose/Objective:

Through a departmental quality review process it came to light that there was a notable number of rescans in the pelvic radiotherapy patient cohort, due to insufficient bladder volume or excessive rectal filling. In line with national legislation concerning justification in medical exposures to ionising radiation, this was identified as an area for improvement. The following main objectives were outlined: • Reduce the number of rescans due to inappropriate bladder and bowel volumes found at contouring stage • Establish whether the use of pelvic min-scans in Radiotherapy CT is justified under legislation • Confirm the accuracy of calculated bladder volumes from the mini-scan against contoured bladder volumes

Material/Methods:

The data collection period of the study ran for two months from May 4th to July 6th, 2023. A data collection sheet was created by CT staff, with a view to capturing a broad range of data. It was hoped that this could be used to analyse a number of issues that had been experienced by the departments. Data included site, use of contrast, use of enemas, volume of water drank by the patients and the length of time they waited before proceeding to scan. Data related to the mini and full scan doses, in addition to calculated bladder volume was also entered into the spreadsheet. All pelvic patients who required specific bladder and/or rectal volumes for treatment were included. This resulted in 103 unique encounters documented, with 89 remaining for analysis. Those excluded were due to incomplete data, which could not be retrieved from the CT scanner software of Dosewatch™. Contoured bladder volumes from the Monaco planning software were manually entered as the data analysis stage.

Results: