[A fast procedure of patient set-up verification in pelvic radiotherapy]. / Eine schnelle Bildkorrelationsmethode zur Uberprüfung der Patientenlagerung in der Strahlentherapie.

Accuracy of patient positioning is an important aspect in radiation therapy. The present paper presents a new procedure for the determination of set-up errors in radiotherapy, which is based on a special form of the Fast Fourier Transform (FFT), i.e., the Fast Hartley Transform (FHT). The use of this method allows to compare in short time verification and simulator films, and to calculate the translation vector or the in-plane rotation of the patient. Standard deviations < 1 mm for shifting measurements and < 1 degree for measurements of the rotation were detected, provided that the positioning remained within the common clinical range. The present results were in good agreement with data obtained using a landmark-based method.

Long-term outcome after elective irradiation of the pelvic lymphatics and local dose escalation using high-dose-rate brachytherapy for locally advanced prostate cancer.

PURPOSE: To report the 8-year outcome of local dose escalation using high-dose-rate conformal brachytherapy combined with elective irradiation of the pelvic lymphatics for localized prostate cancer. METHODS AND MATERIALS: One hundred forty-four consecutively treated men (1986-1992) were recorded prospectively. Twenty-nine (20.14%) patients had T1b-2a tumors, and 115 (79.86%) patients had T2b-3 tumors according to, respectively, American Joint Committee on Cancer/Union Internationale Contre le Cancer 1992. All patients had a negative nodal status, proven by CT or MRI. The mean initial PSA value was 25.61 ng/mL (Initial value for 41.66% of patients was <10 ng/mL, for 21.52% was 10-20 ng/mL, and for 32.63% was >20 ng/mL). The total dose applied by external beam radiotherapy was 50 Gy in the pelvis and 40 Gy in the prostate. The high-dose-rate brachytherapy was delivered in two fractions, which were incorporated into the external beam treatment (after 20-Gy and 40-Gy external beam radiotherapy dose). The dose per fraction was 15 Gy for the PTV1 (peripheral prostate zone) and 9 Gy for the PTV2 (entire prostatic gland). Any patient free of clinical or biochemical evidence of disease was termed bNED. Actuarial rates of outcome were calculated by Kaplan-Meier and compared using the log-rank. Cox regression models were used to establish prognostic factors of the various measures of outcome. RESULTS: The median follow-up was 8 years (range 60-171 months). The overall survival rate was 71.5%, and the disease-free survival rate was 82.6%. The bNED survival rate was 72.9%. Freedom from local recurrence for T3 stage was 91.3%, whereas for G3 lesions it was 88.23%. Freedom from distant recurrence for T3 stage was 82.6% and for G3 lesions 70.59%. Univariate survival analyses revealed that low stage (T1-2), low grade (G1-2), no hormonal therapy, initial PSA value less than 40 ng/mL, and PSA normalization <1.0 ng/mL after irradiation were associated with long survival. In multivariate analyses, initial PSA value, PSA kinetics after radiation therapy, and no adjuvant hormonal treatment were independent prognostic factors. Grade 3 late radiation toxicity (according to RTOG/EORTC scoring scheme) was 2.3% for the genitourinary system in terms of cystitis and 4.10% for the gastrointestinal system in terms of proctitis. Grades 4 and 5 genitourinary/gastrointestinal morbidity was not observed. A history of transurethral resection of the prostate with a median interval of less than 6 months from radiotherapy was associated with a high risk of genitourinary toxicity. CONCLUSION: The 8-year results confirm the feasibility and effectiveness of combined elective irradiation of the pelvic lymphatics and local dose escalation using high-dose-rate brachytherapy for cure of localized and especially high-risk prostate cancer.