ESTRO 2024 - Abstract Book

S5620

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2024

Results:

Six patients, with 2 imaging time points during their RT were included in the blinded assessment. This included 12 CBCT_BH and 12 CBCT_FB datasets each pair acquired consecutively. In total 4 observer groups completed the scoring criteria assessment, which included an EXP group and 3 clinical OBS groups. All groups evaluated 24 imaging datasets acquired in 12 treatment sessions, resulting in 96 image datasets assessed. OQ scores for all paired EXP datasets improved using BH image (Figure 2). Eleven of twelve (92%) BH images were rated as having no to minor artefacts i.e. a score of 1 -2 for OQ, with one score (8%) being 3. For the CBCT_FB 11/12 (92%) were rated a 3 or 4. The mean (SD) OQ for BH and FB images were 1.5 (0.67) and 3.33 (0.78) respectively. The difference between repeated measurements were statistically significant (Sig.) (p<0.001). The sum of all OQ scores were 18 for BH, and 41 for FB, showing an improvement of 56.1% using BH when scored by EXP.

For OBS groups, OQ score for CBCT_BH were between 1-2 for the majority of datasets (28/36, 78%) (Figure 2), whereas the CBCT_FB were scored 3-4 in most cases (35/36, 97%). The mean (SD) for CBCT_BH and CBCT_FB were 2.11 (0.57) and 3.64 (0.54) respectively. 32/36 (89%) datasets showed improved scores with CBCT_BH, and 4/36 (11%) datasets were scored the same. The difference between repeated scores were Sig. (p<0.001). An improvement of 42% was observed using CBCT_BH acquisition.