A study on strategies to optimize bladder volume consistency in radiotherapy patients.

[OBJECTIVES] This study aimed to investigate the impact of multi-step workflow optimization on enhancing the consistency of bladder volume among patients receiving pelvic radiotherapy.

[METHODS] Patients requiring bladder preparation were selected through simple random sampling before and after the implementation of optimization measures in June 2024. Each cohort included 5 patients with prostate cancer, 15 with cervical cancer, and 10 with rectal cancer cases. Statistical methods were used to evaluate the correlation and consistency between bladder volume measured by cone-beam CT (V) and a portable scanner (V), as well as the differences of the absolute bladder volume discrepancy (|V-V|), before and after the implementation.

[RESULTS] Pearson correlation analysis showed that a strong correlation between V and V both pre-optimization measures (r = 0.75, P < 0.001) and post-optimization measures (r = 0.73, P < 0.001). The mean of V-V was 30.67 mL, with a standard deviation (SD) of 51.40 mL, and the limits of agreement was (- 70.07, 131.40) mL before the implementation. The mean decreased to 5.03 mL, with a SD of 26.02 mL, and the limits of agreement was (- 45.97, 56.03) mL after the implementation. Wilcoxon rank-sum test revealed that the volume of |V-V| before was 39.00 (18.00, 67.00) mL, and it was 22.00 (15.00, 28.50) mL after with a statistically significant (Z = -7.66, P < 0.001).

[CONCLUSIONS] Multi-step workflow optimization reduced the standard deviation of differences between CBCT-derived and scanner-derived bladder volumes (V and V), decreased the absolute volume discrepancy (|V-V|), and improved bladder volume consistency in patients with prostate, cervical, and rectal cancers.