rectum V50) were obtained corresponding to each image data set and the difference was recorded. Results: There were statistically significant differences in all DVH parameters between the 2 image data sets, with the exception of the V100. Excluding one patient in whom there was an 11% decrease in the V100 from 99.5 to 88.5 with and without stylets, the median decrease in prostate V100 was not significant. However, there was a 3.4% decrease for the V125 (p ! 0.001). For urethra V100, the difference was impressive with a mean of 6 and standard deviation (SD) of 12 between the 2 data sets (p ! 0.001). A similar large discrepancy was found for rectum V50 with a mean of 7 and SD of 11.9 (p ! 0.001). Conclusions: Significant differences were noted in terms of DVH parameters between image data sets acquired with and without rigid stylets for the purpose of real-time intraoperative HDR planning for prostate BT. While the difference in terms of prostate coverage may not be clinically relevant, there were large variations in urethral and rectal dosimetry that may result in increased treatment-related toxicity. When using Flexiguide catheters for HDR prostate BT, we recommend performing the intraoperative planning based on an image set with the rigid stylets removed. PO40 Long-Term Outcome and Late Toxicity Analysis for Clinically Localized Prostate Cancer Treated With Permanent Interstitial Brachytherapy Hong Ye, MS, Alvaro A. Martinez, MD, Michelle Wallace, RN, Kimberly Marvin, BS, Larry Kestin, MD, Michel Ghilezan, MD, PhD, Gary Gustafson, MD. Radiation Oncology, William Beaumont Hospital, Royal Oak, MI. Purpose: We are reporting the 8-year clinical outcome and late toxicity for patients treated with permanent interstitial brachytherapy for clinically localized prostate cancer at Oakland University William Beaumont Medical School. Materials and Methods: Two hundred seven patients were consecutively treated from 1993 to 2007 with either 103 Pd or 125 I monotherapy. The minimum peripheral dose was 120 Gy for 103 Pd and 145 Gy for 125 I. Clinical outcomes were measured and biochemical failure was analyzed by the Phoenix (nadirþ2 ng/mL) definition. Late genitourinary (GU) and gastrointestinal (GI) toxicities were graded by using the NCI Common Toxicity Criteria Version 3.0. The highest toxicity scores at any given time were analyzed using Pearson’s chi-square and evaluated as grade 0-1 vs. grade 3 2 and as grade 0-2 vs. grade 3 3, broken down by risk groups. Results: Average age at time of treatment was 66.5 years (47e83 years). The median followup time was 7.4 years (1.1e14.8 years). By using NCCN risk classification, eighty seven percent of patients were in the low-risk group. At 8 years, biochemical control (BC) and overall survival (OS) for the entire cohort was 81.7% and 83.1%, respectively. For low versus intermediate/higherisk group, BC was 80.9% and 87.1%; OS was 85.3% and 73.4%, respectively. Eight-year BC was not significantly different between low and intermediate/high-risk groups, nor was OS, LR, DM, and DFS. GU grade 3 2 toxicities of frequency/urgency (1.1% vs. 3.6%), urinary retention (2.8% vs. 3.6%), hematuria (2.2% vs. 3.6%), and urethral stricture (0.6% vs. 3.6%) were not found to be significantly different between low- and intermediate/high-risk groups. Any late grade 3 2 and grade 3 3 GI toxicity occurred in 0.5% and 0% in low- and intermediate/high-risk groups. Conclusions: Excellent long-term outcomes and very low late toxicities rates were found in low- and appropriately selected intermediate/high-risk patients. PO41 Post Mortem Analysis of Seed Placement in Prostate Brachytherapy: A Case Study Ado J. van Rensburg, PhD 1 , Wayne van Niekerk, MD 2 . 1 Radiation Oncology, Steve Biko Academic Hospital, Pretoria, Gauteng, South Africa; 2 Gauteng Oncology, Johannesburg, Gauteng, South Africa. Purpose: A patient who had undergone prostate brachytherapy died unexpectedly from unrelated causes three weeks after the implant was performed. His family requested that his body should be cremated. It was decided to harvest the prostate from the body. This afforded us the ideal opportunity to physically verify the seed placement. Materials and Methods: A prostate of a patient was implanted with 125 I seeds. Due to a previous hip replacement there was pelvic interference since the affected leg could not be hyper flexed and the implant was performed in two stages. The CT artifacts also made the post plan challenging. The prostate, along with the adjacent sections of bladder and rectum was removed during a post mortem. The prostate was scanned again, a new post-op plan generated from these CT’s and the prostate dissected by 5mm thick transaxial slices in analogy to the US study. The intra-op and two post-op plans could then be compared and augmented by the information obtained by the dissection. Results: There was a good correlation between the three plans. All the seeds bar one were recovered. It was determined that the missing seed must have been lost through the urethra. Conclusions: The dynamic feedback implant technique used by our group gives good results. The intra-op dose distribution is a good predictor of the actual dose delivered. Due to the shape of the urethra one should never use a needle placed directly under it as a seed can be deposited unknowingly in the urethra and thus expelled. GENERAL POSTERS ThursdayeSaturday PO42 Withdrawn PO43 ZephyrÔ e A Novel ‘‘Aircushion’’ Patient Transportation System for Transferring Brachytherapy Patients for Imaging and Treatment While Minimizing Risk of Applicator Displacement Subir Nag, MD. Radiation Oncology, Kaiser Permanente Medical Center, Santa Clara, CA. Purpose: Three-dimensional imaging is an important component of modern brachytherapy, allowing precise location of the applicator, tumor and surrounding normal tissues. The resultant improvement in dose distribution by using 3-D imaging would be lost if there were even small ( !0.5 cm) applicator movement with respect to the tumor or normal tissues. Hence, ideally, the applicator insertion, CT or MR imaging and HDR treatment should be done in the same room, without needing to move the patient. Since this is available in very few institution, most centers move the patient from the procedure room to the imaging room and then to the treatment vault. Options in patient transportation include log-rolling the patient, using smooth slider boards or rigid stretchers which are cumbersome and risk applicator displacement and patient discomfort. Materials and Methods: The ZephyrÔ is a novel ‘‘air-bearing’’system that facilitates brachytherapy patient transportation without applicator movement, first installed at Kaiser Permanente, Santa Clara. The system consists of a flat, rigid, patient transport sled, stirrups and a transportation gurney. The patient is placed on the Zephyr sled for applicator insertion. The caudal end of the Zephyr sled has of side rail extensions to allow attachment of stirrups for insertion of pelvic brachytherapy applicators in lithotomic position while allowing AP and lateral fluoroscopy and CT imaging. A caudal extension attachment has being recently devised to allow the legs to be lowered out of stirrups, if needed, for imaging. After applicator insertion, an air blower creates a thin cushion of pressurized air between the Zephyr sled and the procedure table, enabling virtually effortless movement of the sled like a hovercraft. The sled (with the patient on it) is moved on to the gurney to transport the sled to the CT imaging table and then to the HDR treatment vault. Results: This powerpoint video presentation demonstrates how the Zephyr sled floats on a thin cushion of air thereby facilitating the transfer of the brachytherapy patient from the procedure room to the imaging couch and then to the treatment vault. We confirm the ease of transporting patients in lithotomic position and the lack of applicator displacement by using this patient transportation system. S97 Abstracts / Brachytherapy 10 (2011) S14eS101