Portal dosimetry for VMAT using integrated images obtained during treatment

Abstract

This method of predicting integrated portal images provides a convenient means of verifying dose delivered using VMAT, with minimal image acquisition and data processing requirements.

Initial clinical experience with Epid-based in-vivo dosimetry for VMAT treatments of head-and-neck tumors

“…Preliminary results on phantoms and in-vivo have shown the feasibility and the sensitivity of this approach to detect dose discrepancies also for these complex techniques. Comparable findings were recently published by Bedford et al [25] and by French researchers [26,27], who developed a similar strategy to ours for Epid-based IVD, following the occurrence in France of a series of accidents in radiotherapy in recent years.…”

Quantifying the performance of in vivo portal dosimetry in detecting four types of treatment parameter variations

“…Though this study shares some similarities with the present report, it considered only one type of error (MLC position) in one disease site and used phantom-based measurements. Also similar is the recent study by Bedford et al 35 that considered multiple sources of error (MU scaling, MLC calibration, and gantry angle errors). However, this study did not quantify the detectability of the test through ROC or other methodology and it was also phantom based.…”

A novel method for sub‐arc VMAT dose delivery verification based on portal dosimetry with an EPID

“…Liu et al evaluated the pass rate for output errors of 5% or more and gantry angle of at least 5 degrees. Bedford et al evaluated 10 types of dosimetric error during VMAT delivery. However, the introduced errors were larger than in our work (e.g., output errors of 10% and leaf positioning errors of 5–10 mm, compared to output errors < 2% and leaf position errors < 1.5 mm in our work).…”

“…In recent years, several groups have investigated the use of EPIDs for VMAT QA . Initial efforts focused on verification of the integral VMAT dose (full‐arc approach), either in 2D or reconstructed in 3D . A potential disadvantage of full‐arc dose verification is that deviations during brief periods of the VMAT delivery are obscured, or compensated in other parts.…”