Abstract book - ESTRO meets Asia

S6 ESTRO meets Asia 2018

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improved treatment delivery for VMAT plans using 6X-FFF compared to 6X-FF. BOT values (Mean ± SD) 6.892 ± 0.91 & 3.174 ± 0.17 min. Conclusion Evaluation of plan based on different quality parameter gives better assessment of Treatment plans. Appreciation of FFF and FF plans should not be limited only to reduction of treatment time. Correlation of inter fraction motions for patients on couch will be a valid tool for the appraisal of FFF-RA treatments. The increase in the speed of MLC can further add advantage to a faster treatment delivery. The lateral scatter was low in FFF compared with FF beams. Linac FFF mode has an advantage of faster treatment capability compared to FF modality. Clinical significance of our findings depends on the size and location of the tumor and FFF plans were a touch superior when compared to FF with analyzed with the analyzed parameters. OC-019 Long-term report of total marrow or total lymphoid IMRT in advanced leukemia, myeloma and lymphoma. S. Vagge 1 , A. Dominietto 2 , F. Guolo 3 , A.M. Carella 2 , R.M. Lemoli 3 , A. Bacigalupo 4 , E. Angelucci 2 , R. Corvò 5 1 IRCCS Policlinico San Martino, Radiation Oncology, Genova, Italy 2 IRCCS Policlinico San Martino, Hematology, Genova, Italy 3 University of Genoa, Hematology, Genova, Italy 4 Policlinico Universitario A. Gemelli, Hematology, Roma, Italy 5 University of Genoa, Radiation Oncology, Genova, Italy Purpose or Objective During the last three decades, total body irradiation (TBI) continues to play an important role in the conditioning regimens for patients undergoing stem-cell transplant (SCT) for a wide variety of advanced hematological malignancies. However, TBI showed boundaries in dose limits for toxicity in allogenic and moreover in autologous stem cell transplantation. Currently, the choice of conditioning regimen is based on the use of the least-toxic regimen to achieve the optimal therapeutic result. This report aims to assess the feasibility of a conditioning strategy based on high dose chemotherapy and whole- body radiotherapy focused on selective extensive tumor burden irradiation, both in allogenic and autologous stem Since December 2009, sixty-two patients (pts) have been irradiated by helical tomotherapy (HT) to extensive target before allogenic or autologous transplantation. Selected total marrow irradiation (TMI) schedules were planned to treat high risk or fragile acute leukemia patients (ALL or AML) or multiple myeloma (MM) before autologous or allogenic transplantation. While total lymphoid irradiation (TLI) was planned to treat patients with refractory or relapsed (R/R) Hodgkin (HD) or Non-Hodgkin lymphomas (NHL). Results TMI and TLI allowed delivering therapeutic dose over extensive selected targets with wide reduction of toxicity to all the organs at risk (OARs). The higher radiation doses rate to the OARs is reduced from 30% to 70%. Allogenic conditioning regimen was TLI (4Gy x 3fx) than fludarabine + endoxan for patients with HD ( 4 pts ). TMI (4Gy x 3fx) + fludarabine + melphalan for patients with MM Proffered papers: Head and neck, haematology, gyn cell transplantation. Material and Methods

Conclusion This planning study extends on previous studies and shows MLD and functional V20 can be reduced to lung that is both perfused and ventilated, without clinically significant increases in dose to the heart or other organs at risk. Further prospective evaluation of this technique is required to determine if clinical benefit is realised. OC-018 Dosimetric comparison of Flattened and Un-flattened Beams for Brain Lesions. P.K. Mani 1 , S. Paulpandi 1 , K. Vittal 1 , K. Bayyareddygari 1 , V. Manoor Ural 1 , N. Veeraragavan 1 , V.R. Subramanian 2 , C.A. Radha 2 1 Apollo Hospital, Radiation Oncology, Bangalore, India 2 Vellore Institute of Technology, Department of Physics, Vellore, India Purpose or Objective To compare FF & FFF with Volumetric Modulated Arc Therapy (VMAT) for brain metastasis and apprise the dosimetric differences based on various Plan Quality Indicies (PQI) Material and Methods 20 patients with single Brain mets were selected for this study. VMAT treatment plans were generated using 6X-FF and 6X-FFF of TrueBeam ST X Linear Accelerator (Varian medical systems, USA), modeled in Eclipse Treatment Planning System (Version 11.0.31). 15Gy in single fraction was prescribed to the target volume. VMAT planning involves placement of 1-2 full arcs with dose rate of 600MU/min, 1400MU/min for 6X-FF and 6X-FFF respectively. Optimization process was carried out with constraints to keep normal structures doses as low as possible following the QUANTEC constraints. Final dose calculation was performed with Analytical Anisotropic Algorithm (AAA). All plans were normalized to target mean. Plan Evaluation was done based on RTOG plan quality parameters- Conformity Index, Homogeneity Index, delivery time, monitor unit, Quality of Coverage, Tumor coverage factor, Tumor Under Dosage factor, Healthy tissue over dosage. Confirmation number between 6FF vs. 6FFF. Organs at Risk (OAR’s) like Brain stem, Optic chiasm, Lens (Right and Left), Eye (Right and Left) and Brain were analyzed statistically using D Max and D Mean . Technical parameters. Results The following are results of FFF and FF are as follows, CI values (Mean ± SD) were 1.09 ± 0.65 & 1.07 ± 0.60. HI values (Mean ± SD) were 1.10 ± 0.04 & 1.10 ± 0.05. Brain Stem values (D Max ) (Mean ± SD) were 11.87 ± 0.65 & 11.72 ± 0.68 Gy . Optic Chiasm values (D Max ) (Mean ± SD) 9.15 ± 1.28 & 8.92 ± 1.22 Gy . Eye (Right & Left) values (D Max ) (Mean ± SD) 2.01 ± 0.63, 2.00 ± 0.66 and 2.02 ± 0.80, 2.01 ± 0.66 Gy. Lens (Right & Left) values (D Max ) (Mean ± SD) 1.11 ± 0.56, 1.13 ± 0.59 and 1.22 ± 0.53, 1.33 ± 0.54 Gy . Normal Brain values (D Max ) (Mean ± SD) 11.04 ± 0.24 & 11.09 ± 0.22 Gy. MU values (Mean ± SD) 4086.7 ± 545.1 & 4311.9 ± 339.1 MU.This study showed reduced BOT with