ESTRO 2024 - Abstract Book

S5621

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

ESTRO 2024

OQ scores improved by 56.1% for EXP on CBCT_BH, and by 42% for the OBS. Summed scores for all structures (CA, SMA, SMV, DUO, GTV/ITV and PTV), for EXP and OBS showed an improvement in visualisation and confidence in registration for CBCT_BH (all>28.6%).

Group/structure CBCT_BH CBCT_FB Improvement (%) EXPERT OQ 18 41 56.1 CA 15 35 57.1 SMA 14 38 63.2 SMV 23 45 48.9 DUO 26 36 27.8 GTV/ITV 16 42 61.9 PTV cover 20 28 28.6 TOTAL 132.0 265.0 50.2

OBSERVER OQ

25.3

43.7

42.0

CA

17.3

27.0

35.8

SMA

19.0

31.3

39.4

SMV

27.0

39.7

31.9

DUO

23.0

32.7

29.6

GTV/ITV

21.7

33.3

35.0

PTV cover

20.3

30.3

33.0

TOTAL

153.7

238.0

35.4

Table 1. Sum of all scores, percentage improvement (%) for OQ and each individual structures for CBCT_BH and CBCT_FB is shown (for OBS groups, the average sum and % is presented).

The EXP and OBS group results across all summed scores showed a overall 50.2% and 35.4% improvement respectively. Both groups showed a Sig. improvement for all structures (p=<0.001, except for the EXP duodenum and PTV coverage where p=0.001 and 0.006 respectively).

Conclusion:

CBCT_BH significantly improved OQ, visualisation of structures and RTT confidence in decision making for pancreatic RT. This is the first study to quantify the improvement of using CBCT_BH in PDAC. Improvements were found across EXP and OBS groups, showing potential to improve the safety and accuracy of dose escalated RT in future studies.

Keywords: image quality, CBCT, pancreas

References: