Comparative analysis of the effects of belly board and bladder distension in postoperative radiotherapy of rectal cancer patients.
OBJECTIVE
To compare the effect of reducing the irradiated small-bowel volume with the use of belly board, bladder distension or both methods combined, in patients with rectal cancer undergoing postoperative pelvic radiotherapy.


METHODS
This study enrolled 20 consecutive patients with rectal cancer who were scheduled to receive postoperative pelvic radiotherapy. All patients underwent four sets of CT scans under four different methods as follows: group I: empty bladder without the use of a belly board; group II: empty bladder with the use of a belly board; group III: bladder distension without the use of a belly board; group IV: bladder distension with the use of a belly board. The conventional three-field treatment plan was made using a three-dimensional treatment planning system. The irradiated small-bowel volume was calculated at 10% intervals from 10% to 100% of the prescribed dose.


RESULTS
The volume of the irradiated small bowel decreased in the order of group I, group II, group III, and group IV at all dose levels (p < 0.001). In comparison to group I, the mean absolute volume reductions (relative volume reduction) of the irradiated small bowel were 41.5 +/- 20.1 cm(3) (33.9 +/- 12.9%) in group II, 76.6 +/- 30.5 cm(3) (55.1 +/- 17.8%) in group III, and 98.5 +/- 36.7 cm(3) (70.7 +/- 14.5%) in group IV.


CONCLUSIONS
Bladder distension was a more effective method than the belly board for reducing the irradiated small-bowel volume in postoperative pelvic radiotherapy of rectal cancer patients. The combination of the belly board and bladder distension showed an additive effect and was the most effective method for reducing the irradiated small-bowel volume.
Kim
Tae Hyun
TH
Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, Korea.
Kim
Dae Yong
DY
Cho
Kwan Ho
KH
Kim
Young Hoon
YH
Jung
Kyung Hae
KH
Ahn
Joong-Bae
JB
Chang
Hee Jin
HJ
Kim
Joo-Young
JY
Choi
Hyo Seong
HS
Lim
Seok-Byung
SB
Sohn
Dae Kyung
DK
Jeong
Seung-Yong
SY
D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D000328:Adult; D000368:Aged; D003131:Combined Modality Therapy; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007421:Intestine, Small / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011182:Postoperative Care; D011829:Radiation Dosage; D011835:Radiation Protection; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D012007:Rectum / Q000473:pathology; D014057:Tomography, X-Ray Computed; D001743:Urinary Bladder / Q000000981:diagnostic imaging