CT-fluoroscopy guided interstitial brachytherapy with image-based treatment planning for unresectable locally recurrent rectal carcinoma.
OBJECTIVE
The aim of the study is to develop high-dose-rate (HDR) conformal interstitial brachytherapy by means of combined CT-fluoroscopy guidance with CT-based treatment planning for locally recurrent rectal carcinoma.


METHODS
Brachytherapy needle insertion was guided with a helical CT scanner providing continuous fluoroscopy reconstruction. A video monitor placed adjacent to the CT gantry simultaneously allowed the operator to see the process of needle insertion. Final CT images were transferred by an online system to the treatment-planning computer, which reconstructed the implant needles and organ contours. The doses in planning target volume were normalized and geometrically optimized. The patients received a brachytherapy dose at 5 Gy twice daily with a hypofractionated accelerated schedule at a total dose of 30-50 Gy with or without external radiation therapy. Eighteen patients were treated with this procedure.


RESULTS
Ten to thirty-six needles (average, 17.3) were successfully placed to the planning target volume in each patient. The average time for CT fluoroscopy was 357 seconds for each procedure. No accident was seen at needle insertion, but 2 patients developed incomplete peroneal nerve palsy after needle removal, but gradually recovered. CT-based treatment planning was faster and more accurate than projection reconstruction with conventional radiograms. Analysis of the dose volume histogram showed conformal dose distribution to the target, while avoiding normal structures.


CONCLUSIONS
CT fluoroscopy guidance ensures safety and increases the accuracy of needle placement in brachytherapy. Conformal high-dose-rate (HDR) interstitial brachytherapy with CT-based treatment planning is a method worth considering for locally recurrent rectal cancer.
Sakurai
Hideyuki
H
Department of Radiation Oncology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan. hsakurai@med.gunma-u.ac.jp
Mitsuhashi
Norio
N
Harashima
Koichi
K
Muramatsu
Hiroyuki
H
Ishikawa
Hitoshi
H
Kitamoto
Yoshizumi
Y
Suzuki
Yoshiyuki
Y
Saitoh
Jun-ich
JI
Nonaka
Tetsuo
T
Akimoto
Tetsuo
T
Nakayama
Yuko
Y
Hasegawa
Masatoshi
M
Nakano
Takashi
T
D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D001918:Brachytherapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D020266:Radiotherapy, Conformal / Q000379:methods*; D011882:Radiotherapy, High-Energy; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods