Bladder filling variation during radiation treatment of prostate cancer: can the use of a bladder ultrasound scanner and biofeedback optimize bladder filling?
OBJECTIVE
To investigate the use of a bladder ultrasound scanner in achieving a better reproducible bladder filling during irradiation of pelvic tumors, specifically prostate cancer.


METHODS
First, the accuracy of the bladder ultrasound scanner relative to computed tomography was validated in a group of 26 patients. Next, daily bladder volume variation was evaluated in a group of 18 patients. Another 16 patients participated in a biofeedback protocol, aiming at a more constant bladder volume. The last objective was to study correlations between prostate motion and bladder filling, by using electronic portal imaging device data on implanted gold markers.


RESULTS
A strong correlation between bladder scanner volume and computed tomography volume (r = 0.95) was found. Daily bladder volume variation was very high (1 SD = 47.2%). Bladder filling and daily variation did not significantly differ between the control and the feedback group (47.2% and 40.1%, respectively). Furthermore, no linear correlations between bladder volume variation and prostate motion were found.


CONCLUSIONS
This study shows large variations in daily bladder volume. The use of a biofeedback protocol yields little reduction in bladder volume variation. Even so, the bladder scanner is an easy to use and accurate tool to register these variations.
Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. m.stam@rther.umcn.nl
Marcel R
MR
Stam
Emile N J Th
EN
van Lin
Lisette P
LP
van der Vight
Johannes H A M
JH
Kaanders
Andries G
AG
Visser
D001676:Biofeedback, Psychology / Q000502:physiology*; D006801:Humans; D008297:Male; D009068:Movement; D011467:Prostate; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D012044:Regression Analysis; D018709:Statistics, Nonparametric; D014463:Ultrasonography; D001743:Urinary Bladder / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D016526:Workload