Dosimetric comparison of volume-based and inverse planning simulated annealing-based dose optimizations for high-dose rate brachytherapy.

The aim of this study was to compare the clinical benefits of inverse planning simulated annealing (IPSA)-based optimization over volume-based optimization for high-dose rate (HDR) cervix interstitial implants. Overall, 10 patients of cervical carcinoma were considered for treatment with HDR interstitial brachytherapy. Oncentra Master Plan brachytherapy planning system was used for generating 3-dimensional HDR treatment planning for all patients. All patient treatments were planned using volume-based optimization and inverse planning optimization (IPSA). The parameters V100, V150, and V200 for the target; D(2 cm³) of bladder, rectum, and sigmoid colon; and V80 and V100 for bladder, rectum, and sigmoid colon were compared using dose-volume histograms (DVHs). The conformity index (CI), relative dose homogeneity index, overdose volume index (ODI), and dose nonuniformity index (DNR) were computed from cumulative DVHs. Good target coverage for prescription dose was achieved with volume-based optimization as compared with IPSA-based dose optimization. Homogeneity was good with the IPSA-based technique as compared with the volume-based dose optimization technique. Volume-based optimization resulted in a higher CI (with a mean value of 0.87) compared with the IPSA-based optimization (with a mean value of 0.76). ODI and DNR are better for the IPSA-based plan as compared with the volume-based plan. Mean doses to the bladder, rectum, and sigmoid colon were least with IPSA. IPSA also spared the critical organs but with considerable target conformity as compared with the volume-based plan. IPSA significantly reduces overall treatment planning time with improved reduced doses to the organs at risk compared with the volume-based optimization treatment planning method.

Analysis of X-knife and surgery in treatment of arteriovenous malformation of brain.

BACKGROUND: The goal of treatment in arteriovenous malformation (AVM) is total obliteration of the AVM, restoration of normal cerebral function, and preservation of life and neurological function. AIM: To analyze the results of X-knife and surgery for AVM of the brain. The endpoints for success or failure were as follows: success was defined as angiographic obliteration and failure as residual lesion, requiring retreatment, or death due to hemorrhage from the AVM. MATERIALS AND METHODS: From May 2002 to May 2007, 54 patients were enrolled for this study. Grade I AVM was seen in 9%, grade II in 43%, grade III in 26%, grade IV in 9%, and grade V in 13%. Thirty-eight patients were treated by microsurgical resection out of which Grade I was seen in 5 patients, Grade II was seen in 17 patients, Grade III was seen in 9 patients and Grade V was seen in 7 patients. Rest of the sixteen patients were treated by linear accelerator radiosurgery out of which Grade II was seen in 6 patients, Grade III was seen in 5 patients and Grade IV was seen in 5 patients. The follow up was in range of 3-63 months. In follow up, digital subtraction angiography/ magnetic resonance angiography (DSA/MRA) was performed 3 months after surgery and 1 year and 2 years after stereotactic radiosurgery (SRS). RESULTS: Among the patients treated with X-knife, 12/16 (75%) had proven angiographic obliteration. Complications were seen in 4/16 (25%) patients. Among the patients treated with microsurgical resection, 23/38 (61%) had proven angiographic obliteration. Complications (both intraoperative and postoperative) were seen in 19/38 (50%) patients. CONCLUSIONS: Sixty-one percent of patients were candidates for surgical resection. X-knife is a good modality of treatment for a low-grade AVM situated in eloquent areas of the brain and also for high-grade AVMs, when the surgical risk and morbidity is high.