Volume 2 Issue 4
The Effects of Flattened and Flattening-Filter-Free Beam on Treatment Plans
Yue Yan, Poonam Yadav, Michael Bassetti, MD, PhD, Paul Harari, MD, Bhudatt R. Paliwal*
We investigated the dosimetric and biological differences between the flattened and flattening-filter-free (FFF) beam plans for the 6 and 10 MV photon beams from the Varian TrueBeam system. One hundred and four treatment plans were created for 13 cases involving 3 different cancer sites: head & neck, lung and prostate. Significant dose sparing was obtained with FFF beams for the head & neck cases, especially for cases with large field sizes (≈16×20 cm2). Overall, the FFF beams provide similar target coverage as the flattened beams. Additionally, the FFF beams resulted in improved dose sparing to organs at risk compared to the conventional flattened beams, for both static intensity modulated radiotherapy and volumetric modulated arc therapy plans.
Effect of Blockade of Indoleamine 2, 3-dioxygenase in Conjunction with Single Fraction Irradiation in Rat Glioma
Jonatan Ahlstedt*, Karolina Förnvik, Crister Ceberg, Henrietta Redebrant Nittby
Glioblastoma (GBM), or WHO Astrocytoma grade IV, is the most common primary brain tumour in adults. GBM is shown to escape host immune surveillance through many paths, of which expression of indoleamine 2,3-dioxygenase (IDO), leading to induction and accumulation of regulatory T-cells in the tumour microenvironment, has been shown to be of importance. 1-Methyl tryptophan (1-MT) is an inhibitor of IDO that has been shown to have a positive effect on survival in experimental models of GBM. In this study, we evaluate the effect of combined single-fraction irradiation of 8 Gy with 1-MT treatment in Fischer rats carrying the RG2 glioma model. We also investigate expression of IDO in the RG2 model before and after irradiation.
Clinical Research Article
The Dosimetry Characteristics of a Low Energy Photon Intra-Operative Radiotherapy System
Bin Ouyang#, Zhenyu Wang#, Zhenhua Xiao#, BotianHuang and Bixiu WEN*
Intra-operative radiotherapy (IORT) with high energy electron beam or low energy photon beam possesses advantage of delivering a single high dose radiation directly to the tumor bed during the surgical procedure and preserving the deep normal tissues. With the introduction of light-weighted and easy-tomove device which includes Mobetron® MeV electron beam system (IntraOp Medical Corporation, California, USA), NOVAC™ 7 electron beam system (New Radiant Technology SpA, Italy) and the INTRABEAM® 50 kV X-ray system (Carl Zeiss Medical Company, Germany), IORT technique is applied more frequently in the cancer treatment.