Portal dosimetry correction method for validation of single isocenter VMAT plans for multiple brain metastases.

J Appl Clin Med Phys

Department of Radiation Oncology, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, USA.

Published: September 2022

Portal dosimetry is one option for verification of volumetric-modulated arc therapy (VMAT) planning for multiple brain metastases. However, due to the changing response of the portal imager with photon beam energy, the dose transmitted through closed multileaf collimator (MLC) leaves or narrow MLC gaps may be underestimated by the imager. We present a simple method for correcting for these effects that may be implemented within the Eclipse treatment planning system. We recalculated the predicted portal dose with and without this correction for 20 multiple brain met VMAT plans. Before the correction, 3/20 composite plan fields passed our standard quality assurance (QA) criteria (54/80 individual fields); the average gamma passing rate for the composite plans was 76.9 ± 16.6%, and the average gamma value across the composite plans was 0.67 ± 0.23. After correction, 20/20 composite plan fields passed the QA criteria (80/80 individual fields); the average gamma passing rate for composite plans was 99.2 ± 1.4%, the average gamma value across the composite plans was 0.33 ± 0.90. A measure of plan complexity, the average leaf pair opening could be correlated to the gamma analysis results for the uncorrected plans but not for the corrected plans.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9512355PMC
http://dx.doi.org/10.1002/acm2.13710DOI Listing

Publication Analysis

Top Keywords

average gamma
16
composite plans
16
multiple brain
12
portal dosimetry
8
plans
8
vmat plans
8
brain metastases
8
composite plan
8
plan fields
8
fields passed
8

Similar Publications

Background: Tremor, either in patients with Essential Tremor (ET) or Parkinson's disease (PD), constitutes the most common movement disorder. Stereotactic radiosurgery using Gamma Knife (GK) and linear accelerator (LINAC) systems, is an effective, incisionless treatment modality for ET and PD. Although these technologies have been used clinically since the 1990's, most studies have focused on GK, and efficacy, safety and time to treatment effect (latency) of GK and LINAC have not been compared.

View Article and Find Full Text PDF

Red cell exchange is important to treat acutely ill sickle cell patients, but it is time-consuming. An automated red cell exchange technique using cell separators developed by different manufacturers helps in removal of sickled hemoglobin and improving blood viscosity. The use of these cell separators permits automated red cell exchange to be performed safely and smoothly with the isovolemic hemodilution.

View Article and Find Full Text PDF

Heterogeneity in Risk and Implications for Hepatitis C Reinfection in People Who Inject Drugs in England.

J Viral Hepat

February 2025

Statistics, Modelling and Economics Department, UK Health Security Agency, London, UK.

Chronic hepatitis C virus (HCV) infection is associated with significant morbidity, mortality and health economic burden. Over 90% of HCV cases in England occur in people who inject drugs (PWID). Current treatments for HCV are effective but do not protect against reinfection.

View Article and Find Full Text PDF

The dried fig cv. Sabz of Iran, distinguishes out among the several fig cultivars for its unique characteristics and excellent properties. The aims to this study were 1) Carefully monitoring the resulting phenotypic changes in growth patterns, leaf morphology, shoot traits, root characteristics, and other relevant traits after irradiated with different gamma rays; 2) Investigating the LD25, 50, 75 and GR25, 50, 75 values at different gamma radiation doses for chose optimum dose.

View Article and Find Full Text PDF

Background: Dosimetric commissioning and quality assurance (QA) for linear accelerators (LINACs) present a significant challenge for clinical physicists due to the high measurement workload and stringent precision standards. This challenge is exacerbated for radiosurgery LINACs because of increased measurement uncertainty and more demanding setup accuracy for small-field beams. Optimizing physicists' effort during beam measurements while ensuring the quality of the measured data is crucial for clinical efficiency and patient safety.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!