Concurrent treatment planning for outpatient high dose rate prostate template implants.
OBJECTIVE
Since November of 1991, we have treated locally advanced (B2-C) prostate cancer using external beam radiotherapy integrated with outpatient high dose rate interstitial implant boost as part of a Phase II clinical trial. This required (a) rapid, automated planning; (b) incorporation of image data and (c) dose optimization.


METHODS
A treatment planning system was designed which integrates imaging and needle guidance with source reconstruction and dose display. All components of treatment planning (reconstruction, optimization, dose prescription, dose display) are largely automated. A rectal reference point was defined which was reproducible and easily verified. No pretreatment planning was required.


RESULTS
As of November 1992, 83 treatments were delivered using this system. Intra-operative treatment decisions were made possible due to the speed and ease of interpretation of the system. The system has proven satisfactory in the operating room. Rectal doses were calculated for all patients, and ranged from 35-79% of the prescribed dose, with a mean of 58%. The first echelon of a Phase II escalating dose trial has been completed, with 22 patients treated over a period of 1 year.


CONCLUSIONS
Outpatient high dose rate brachytherapy appears to be a practical means of boosting locally advanced prostate cancer patients. Rapid treatment planning is possible incorporating on-line ultrasound images to allow immediate dose optimization to be performed during and after implant placement.
Edmundson
G K
GK
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI 48073.
Rizzo
N R
NR
Teahan
M
M
Brabbins
D
D
Vicini
F A
FA
Martinez
A
A
D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D011467:Prostate / Q000000981:diagnostic imaging; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D011879:Radiotherapy Dosage; D014463:Ultrasonography