Braquiterapia Hdr

AMERICAN BRACHYTHERAPY SOCIETY PROSTATE HIGH-DOSE RATE TASK GROUP I-Chow Hsu, MD, Yoshiya Yamada MD, Eric Vigneault MD, Jean Pouliot, PhD August, 2008

General Inclusion Criteria: Clinical Stage T1-T3b and selected T4 Gleason Score Gleason score 2-10 PSA No upper limit, but in almost all cases, patient does not have documented distant metastasis (TxN0M0) Exclusion Criteria: RelativeContraindications Severe urinary obstructive symptoms Extensive TURP defect or TURP within 6 month Collagen vascular disease Absolute Contraindications Unable to undergo anesthesia (general, spinal, epidural, or local) Unable to lay flat Physics and Dosimetry: Sources Ir-192 Treatment Planning System Commissioned prior to first use with source-specific documentation and quality assurance Image-basedTreatment Volumetric base upon contiguous slice acquisition (CT, MR, US) Slice spacing appropriate to resolution requirements Typical intraoperative procedures: ≤ 5 mm Typical planning evaluation: ≤ 3 mm Three-dimensional calculation DVH-based analysis Dosimetry Air kerma strength of each new source should be independently measured and compared to vendor specifications Dose calculation Dosimetry inaccordance with TG43 (1999) and revised TG43U1 (2004) formalisms The prescribed dose will be the intended minimum dose delivered to planning target volume (PTV)

Volume quantifiers for structures with ill-defined extent (urethra and rectum) should be cited in cubic centimeters Intraoperative Procedure: Anesthesia The implant procedure may be done under epidural, spinal or general anesthesia. Epiduralor patient controlled analgesia (PCA) should be used during the post-op period for pain control if inpatient. Implant After loading catheters must be placed with TRUS guidance. The implant catheters must be CT/MR compatible if CT/MR is used for planning. During the implant, attention should be given to keep the catheters in the prostate without perforating the urethra. Posterior rows of cathetersmay be advanced into the seminal vesicles. No fewer than 14 catheters must be in the clinical target volume for adequate coverage without excessive hot spots. Cystoscopy Evaluation of the depth of catheter insertion and avoid perforation of the bladder should be done by flexible cystoscopy. Fiducial Marker To facilitate with the identification of target and normal structures, fiducial markerseeds should be placed under TRUS guidance at the base and the apex of the prostate. A Foley catheter should be inserted in the urethra at the conclusion of the implant procedure to help identify the urethra. Treatment Planning: Treatment Planning Scan Perform after the implant procedure The treatment planning CT/MR scan should be performed with the patient in the treatment position with the Foleycatheter in place. Metallic obturators or non-CT compatible dummy ribbons must be removed prior to the CT/MR scan to reduce imaging artifacts. The scan thickness must be ≤ 0.3 cm and the slices must be contiguous. The brachytherapy target volume and critical structures should be outlined on all slices. The scan should include the entire prostate and the area at least 3 slices (9 mm) above and belowthe prostate and include the perineum to allow visualization of the catheters from tips to outside the patient. The tips of all the catheters must be included. The patient’s external body contours should not be included in the field of view (FOV) in order to maximize the image quality. Dwell Selection and Dwell Time Optimization The dwell time in dwell positions located outside of the PTV should beturned down to minimize normal tissue irradiated.

A dwell time optimization program based on geometric or inverse planning algorithm should be used. Manual optimization is also accepted. Brachytherapy Target Volume The definition of volumes will be in accordance with ICRU Report 58: Dose and Volume Specification for reporting interstitial therapy. The Clinical Target Volume (CTV) is defined...