In vivo dose evaluation during gynaecological radiotherapy using L-alanine/ESR dosimetry.

The dose delivered by in vivo 3-D external beam radiation therapy (EBRT) was verified with L-alanine/electron spin resonance (ESR) dosimetry for patients diagnosed with gynaecological cancer. Measurements were performed with an X-band ESR spectrometer. Dosemeters were positioned inside the vaginal cavity with the assistance of an apparatus specially designed for this study. Previous phantom studies were performed using the same conditions as in the in vivo treatment. Four patients participated in this study during 20-irradiation sessions, giving 220 dosemeters to be analysed. The doses were determined with the treatment planning system, providing dose confirmation. The phantom study resulted in a deviation between -2.5 and 2.1 %, and for the in vivo study a deviation between -9.2 and 14.2 % was observed. In all cases, the use of alanine with ESR was effective for dose assessment, yielding results consistent with the values set forth in the International Commission on Radiation Units and Measurements (ICRU) reports.

High dose rate and external beam radiotherapy in locally advanced prostate cancer.

PURPOSE: To report the outcomes and toxicity of high dose rate brachytherapy as a boost for localized prostate cancer. MATERIALS AND METHODS: Between 1997 and 2000, the medical records of 131 patients with prostate adenocarcinoma who were treated with external beam radiation therapy and high dose rate brachytherapy, were retrospectively analyzed. Furthermore, 55% of the patients received neoadjuvant/concurrent or adjuvant androgen deprivation therapy. Patients were stratified into 2 groups. Group 1 included 65 patients with Gleason score 7, pretreatment prostate specific antigen (PSA) between 10 and 20 ng/mL, and clinical stage T2b. Group 2 included 66 patients with Gleason score between 8 and 10, PSA greater than 20 ng/mL, and clinical stage greater than T2b. RESULTS: At a median follow-up of 62.8 months, the 5-year biochemical control (BC) rate, as defined by the American Society for Therapeutic Radiology and Oncology Phoenix Consensus panel statement, was 81% and overall survival was 91%. BC in Groups 1 and 2 were 87% and 71%, respectively. On univariate analysis risk group, pretreatment PSA and age were significant predictors of BC. However, on multivariate analysis only pretreatment PSA was significant. Using the Radiation therapist oncology group criteria, there were 2 (1.5%) cases of grade 3 acute urinary toxicity. Regarding late side effects (n = 5), 4% of patients had grade 3 genitourinary toxicity and no grade 4 complication was observed. CONCLUSIONS: External beam radiation therapy and high dose rate brachytherapy for prostate cancer resulted in excellent BC, and overall survival with minimal severe, acute, or late complications.