[Individual control of urine volume to improve stability of bladder volume in radiotherapy of urinary tumor].

OBJECTIVE

To explore the training mode of individual urine volume control, to take indi-vidual expected urine volume as the goal of bladder control in patients with urinary system tumors, and to improve the accuracy of bladder control during radiotherapy by active training of bladder receptivity.

METHODS

Twenty-five patients of urinary system tumors were enrolled from May 2019 to September 2019, of whom, 21 patients had prostate cancer, and 4 had bladder cancer. Training of bladder filling started before CT simulation. The patients were required to take the individual bladder filling as the training goal, and the optimal bladder volume range was suggested to be 200－400 mL. After 2－4 weeks of training, the prescribed volume of the bladder was determined according to the patient's bladder receptivity. The volume of the bladder was measured by images of plain CT and images 8-minutes after intravenous contrast injection. The patient's bladder volume was measured using BladderScan before treatment. CBCT (Cone-beam CT) was performed, and bladder volume was measured before treatment. The bladder volume was measured again using BladderScan after treatment.

RESULTS

The mean bladder volume of simulation (V) was (262±130) mL, ranging from 78 mL to 505 mL. The mean self-evaluation bladder volume before radiotherapy (V) was (238±107) mL, ranging from 100 mL to 400 mL. The mean BladderScan measured volume before radiotherapy (V) was (253±123) mL, ranging from 60 mL to 476 mL. The mean cone-beam CT measured volume before radiotherapy (V) was (270±120) mL, ranging from 104 mL to 513 mL. There was a correlation between V and V, V and V, V and V, and there was no significant difference in paired -test. There was a correlation between differences of self-evaluation bladder volume before radiotherapy(V) and simulation CT (V) and differences of self-evaluation bladder volume before radiotherapy (V) and cone-beam CT (V), and there was no significant difference in paired samples by -test.

CONCLUSION

During radiotherapy for urinary system tumors, such as prostate cancer and bladder cancer, with the assistance of BladderScan, the patients could try to hold their urine moderately according to their conditions, and individualized bladder prescription may be beneficial to achieve stable bladder volume during radiotherapy.