A dosimetric selectivity intercomparison of HDR brachytherapy, IMRT and helical tomotherapy in prostate cancer radiotherapy.
OBJECTIVE
Dose escalation in order to improve the biochemical control in prostate cancer requires the application of irradiation techniques with high conformality. The dosimetric selectivity of three radiation modalities is compared: high-dose-rate brachytherapy (HDR-BT), intensity-modulated radiation radiotherapy (IMRT), and helical tomotherapy (HT).


METHODS
Ten patients with prostate adenocarcinoma treated by a 10-Gy HDR-BT boost after external-beam radiotherapy were investigated. For each patient, HDR-BT, IMRT and HT theoretical treatment plans were realized using common contour sets. A 10-Gy dose was prescribed to the planning target volume (PTV). The PTVs and critical organs' dose-volume histograms obtained were compared using Student's t-test.


RESULTS
HDR-BT delivers spontaneously higher mean doses to the PTV with smaller cold spots compared to IMRT and HT. 33% of the rectal volume received a mean HDR-BT dose of 3.86 + or - 0.3 Gy in comparison with a mean IMRT dose of 6.57 + or - 0.68 Gy and a mean HT dose of 5.58 + or - 0.71 Gy (p < 0.0001). HDR-BT also enables to better spare the bladder. The hot spots inside the urethra are greater with HDR-BT. The volume of healthy tissue receiving 10% of the prescribed dose is reduced at least by a factor of 8 with HDR-BT (p < 0.0001).


CONCLUSIONS
HDR-BT offers better conformality in comparison with HT and IMRT and reduces the volume of healthy tissue receiving a low dose.
Hermesse
Johanne
J
Department of Radiation Oncology, Liège University Hospital, Liège, Belgium. jhermesse@chu.ulg.ac.be
Biver
Sylvie
S
Jansen
Nicolas
N
Lenaerts
Eric
E
De Patoul
Nathalie
N
Vynckier
Stefaan
S
Coucke
Philippe
P
Scalliet
Pierre
P
Nickers
Philippe
P
D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy*; D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012007:Rectum / Q000528:radiation effects; D014521:Urethra / Q000528:radiation effects