ESTRO 36 Abstract Book

S525 ESTRO 36 _______________________________________________________________________________________________

funduscopic images MRI can be used to better assess the delivered doses to the target and the organs-at-risk (OAR). The main goal of this feasibility study is to demonstrate that fundus mapping and post implantation MR imaging can be incorporated into the treatment planning workflow of 106 Ru plaque brachytherapy. Material and Methods Patients were scanned in a 0.35 T MR scanner (Magnetom C! Siemens, Germany) after 106 Ru eye plaque implantation. To achieve a good normal tissue contrast for tumor delineation and organ-at-risk (OAR) segmentation a fast low angle shot (FLASH) T1 weighted sequence was utilized (TR = 15 ms, flip-angles = 25°). A second FLASH MRI scan with lower repetition times (TR = 11.2 ms) and flip-angles (20°) was applied in order to display the plaque as a well- defined void with minimal distortion artifacts at the cost of lower signal to noise ratio and less soft tissue contrast. Based on the MRI the resizable 3D eye model of a newly developed treatment planning software (described in detail in [1]) was adapted to the individual patient anatomy in terms of size and plaque position. Furthermore, the funduscopy image was projected onto the retina of the digital 3D eye model. Results The presented method using two MR sequences yielded 3D image sets that allowed segmenting both the anatomical structures and the 106-Ru plaque. The funduscopy image on the other hand is the optimal modality for tumor segmentation. By combination the 3D eye model can be adapted to match the individual patient and thus allow for individual treatment planning and dose calculation (based on MR anatomy) where the post-implantation imaging accounts for the actual position of the plaque with respect to the target and critical structures. This way irradiation times can be calculated which guarantee full tumor coverage. Moreover, the workflow can be applied for treatment plan optimization strategies where plaques are shifted in order to reduce doses to OARs. Conclusion In this feasibility study it was shown that MRI in combination with funduscopy can be used to optimize brachytherapy with 106 Ru plaques. The additional spatial information on plaque position relative to critical structures, tumor geometry as well as position can be used for more precise dose calculations and therefore improved treatment planning. References: [1] G. Heilemann et al. Treatment plan optimization and robustness of 106 Ru eye plaque brachytherapy using a novel software tool. Radiotherapy and Oncology. (in revision) PO-0948 Role of HDR Intraluminal Brachytherapy in carcinoma Esophagus: An institutional experience. P.B. Kainthaje 1 , P. Gaur 1 , A. Malavat 1 , R. Paliwal 1 , V. Sehra 1 1 Dr. Sampurnanand Medical College, Department of Radiotherapy, Jodhpur, India Purpose or Objective To study the profile of patients of Carcinoma Esophagus treated with Intraluminal Brachytherapy (ILBT), the outcome of the treatment in terms of response assessment, toxicity and survival. Material and Methods The study period was between January 2014 and June 2015, with 25 patients of carcinoma esophagus middle third, treated with ILBT either as part of definitive Radiotherapy or as part of palliative Radiotherapy. The patients with unifocal disease ≤10cm in length and with no recorded intra-abdominal or distant metastases received definitive Radiotherapy with 44Gy/22Fr through EBRT with Poster: Brachytherapy: Miscellaneous

concurrent Cisplatin and 5-Flurouracil followed by, 10Gy/2Fr of ILBT boost once weekly. The patients with local advanced disease for palliation received 36Gy/12Fr through EBRT followed by, 10Gy/2Fr of ILBT once weekly. The outcome of treatment was assessed in terms of dysphagia score, dysphagia free survival, toxicities and overall survival. Results Median age of patients was 55 years. Histopathologically 96 % has Squamous cell carcinoma. 16 (64%) of patients were treated with definitive radiotherapy while the rest, 9 (36%) with palliative intent. At a median follow up of 9 months, 13 patients were dysphagia free and there were 5 deaths. One month after completion of treatment, 18 patients were dysphagia free while, 2 patients had partial relief and 5 patients did not notice any relief in dysphagia. 2 patients died within 6 months of completion while, 2 patients developed trachea-esophageal fistula during follow-up.

Conclusion ILBT is a safe modality for boost in treatment of carcinoma esophagus provided, the patients are sele cted with caution. PO-0949 Evaluation of role of Interstitial Brachytherapy in Soft Tissue Sarcoma: Single institute experience V. Pareek 1 1 Jupiter Hospital- Thane, Radiation Oncology, Mumbai, India Purpose or Objective Soft tissue Sarcomas are rare group of solid tumors comprising of 1% of all solid tumors. The management of soft tissue sarcomas have evolved due to advancements in imaging, histopathology, cytogenetics, and the use of multimodality treatment. The treatment strategies emphasizes on the control of disease locally, sparing of limb function and improvement in the quality of life. High dose brachytherapy has formed a part of the management and has the advantage of providing concentrated dose to tumors and sparing of surrounding normal tissues. In this study we examined the clinical outcome of High dose Brachytherapy for STS at our Hospital through retrospective analysis of the prospective database maintained. Objectives: To review the clinical outcome and quality of life in patients with Soft Tissue Sarcoma treated at our center through High dose rate interstitial brachytherapy.