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

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

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_CBCT) and a portable scanner (V_HD5), as well as the differences of the absolute bladder volume discrepancy (|V_CBCT-V_HD5|), before and after the implementation.

Pearson correlation analysis showed that a strong correlation between V_CBCT and V_HD5 both pre-optimization measures (r = 0.75, P < 0.001) and post-optimization measures (r = 0.73, P < 0.001). The mean of V_CBCT-V_HD5 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_CBCT-V_HD5| 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).

Multi-step workflow optimization reduced the standard deviation of differences between CBCT-derived and scanner-derived bladder volumes (V_CBCT and V_HD5), decreased the absolute volume discrepancy (|V_CBCT-V_HD5|), and improved bladder volume consistency in patients with prostate, cervical, and rectal cancers.