PURPOSE Despite numerous advantages of radiochromic film dosimeter (high spatial resolution, near tissue equivalence, low energy dependence) to measure a relative dose distribution with film, one needs to first measure an absolute dose (following previously established reference dosimetry protocol) and then convert measured absolute dose values into relative doses. In this work, we present resu...

The goal of this work is to evaluate the dosimetric impact of an overshooting phenomenon in step-and-shoot IMRT delivery, and to demonstrate a novel method to mitigate the issue. Five pelvis IMRT patients treated on Varian 2100C EX linacs with larger than +4.5% phantom ion chamber point-dose difference relative to planned dose were investigated. For each patient plan, 5 fractions were delivered...

This work outlines the development of a robust method of calculating modulation factors used for the independent verification of MUs for IMRT and VMAT treatments, to replace onerous ion chamber measurements. Two-dimensional fluence maps were calculated for dynamic MLC fields that include MLC interleaf leakage, transmission, and tongue-and-groove effects, as characterized from EPID-acquired imag...

Individual QA for IMRT/VMAT plans is required by protocols. Sometimes plans cannot pass the institute's QA criteria. For the Eclipse treatment planning system (TPS) with rounded leaf-end multileaf collimator (MLC), one practical way to improve the agreement of planned and delivered doses is to tune the value of dosimetric leaf gap (DLG) in the TPS from the measured DLG. We propose that this ste...

PURPOSE In the presence of random uncertainties, delivered radiation treatment doses in patient likely exhibit a statistical distribution. The expected dose and variance of this distribution are unknown and are most likely not equal to the planned value since the current treatment planning systems cannot exactly model and simulate treatment machine. Relevant clinical questions are 1) how to qua...

introduction intensity-modulated radiotherapy (imrt) is becoming an increasingly routine treatment method. imrt can be delivered by use of conventional multileaf collimators (mlcs) and/or physical compensators. one of the most important factors in selecting an appropriate imrt technique is integral dose. integral dose is equal to the mean energy deposited in the total irradiated volume of the p...

The increasing complexity of modern radiation therapy planning and delivery challenges traditional prescriptive Quality Management methods, such as many of those included in guidelines published by organizations such as the AAPM, ESTRO and IAEA. These prescriptive guidelines have traditionally focused on monitoring all aspects of the functional performance of radiotherapy equipment by comparing...

background: to analyze the dosimetric and radio biologic advantages between intensity modulated radiotherapy (imrt) and 3 dimensional conformal radiotherapy (3dcrt) and selection of optimal photon energy for imrt treatments. material and methods: 24 patients with localized prostate carcinoma were planned for 3dcrt and imrt techniques. radiation dose of 54 gy with 2 gy/fraction, was planned to p...

INTRODUCTION Results of use of methodology for VMAT commissioning and quality assurance, utilizing both control point tests and dosimetric measurements are presented. METHODS AND MATERIALS A generalizable, phantom measurement approach is used to characterize the accuracy of the measurement system. Correction for angular response of the measurement system and inclusion of couch structures are ...