Assessment of portal dosimetry accuracy as a QA tool for VMAT clinical treatment plans using dolphin/compass tools

2016 ◽  
Vol 32 ◽  
pp. 265 ◽  
Author(s):  
M. Tomsej ◽  
A. Monseux ◽  
V. Baltieri ◽  
C. Leclercq ◽  
A. Sottiaux
Keyword(s):  
Clinical Treatment ◽  
Portal Dosimetry ◽  
Treatment Plans

30. Assessment of portal dosimetry accuracy as a QA tool for VMAT clinical treatment plans using DOLPHIN/COMPASS tools

2016 ◽  
Vol 32 ◽  
pp. 355-356
Author(s):  
A. Monseux ◽  
V. Baltieri ◽  
A. Sottiaux ◽  
M. Tomsej ◽  
C. Leclercq
Keyword(s):  
Clinical Treatment ◽  
Portal Dosimetry ◽  
Treatment Plans

Building a precise machine-specific time structure of the spot and energy delivery model for a cyclotron-based proton therapy system

2021 ◽  
Author(s):  
Lewei Zhao ◽  
Gang Liu ◽  
Weili Zheng ◽  
Jiajian Shen ◽  
Andrew Lee ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Switching Time ◽  
Specific Model ◽  
Clinical Treatment ◽  
Main Beam ◽  
Log Files ◽  
Treatment Plans ◽  
Beam Delivery ◽  
Precise Machine ◽  
Accelerator System

Abstract Objective: We proposed an experimental approach to build a precise machine-specific beam delivery time (BDT) prediction and delivery sequence model for standard, volumetric, and layer repainting delivery based on a cyclotron accelerator system. Approach Test fields and clinical treatment plans’ log files were used to experimentally derive three main beam delivery parameters that impacted BDT: energy layer switching time (ELST), spot switching time (SSWT), and spot drill time (SDT). This derived machine-specific model includes standard, volumetric, and layer repainting delivery sequences. A total of 103 clinical treatment fields were used to validate the model. Main results: The study found that ELST is not stochastic in this specific machine. Instead, it is actually the data transmission time or energy selection time, whichever takes longer. The validation showed that the accuracy of each component of the BDT matches well between machine log files and the model’s prediction. The average total BDT was about (-0.74±3.33)% difference compared to the actual treatment log files, which is improved from the current commercial proton therapy system’s prediction (67.22%±26.19%). Significance: An accurate BDT prediction and delivery sequence model was established for an cyclotron-based proton therapy system IBA ProteusPLUS®. Most institutions could adopt this method to build a machine-specific model for their own proton system.

scholarly journals Validation of the Acuros XB dose calculation algorithm versus Monte Carlo for clinical treatment plans

2018 ◽  
Vol 45 (8) ◽  
pp. 3909-3915 ◽  
Author(s):  
Lone Hoffmann ◽  
Markus Alber ◽  
Matthias Söhn ◽  
Ulrik Vindelev Elstrøm
Keyword(s):  
Monte Carlo ◽  
Dose Calculation ◽  
Clinical Treatment ◽  
Calculation Algorithm ◽  
Dose Calculation Algorithm ◽  
Acuros Xb ◽  
Treatment Plans

SU-C-BRE-01: 3D Conformal Micro Irradiation Results of Four Treatment Sites for Preclinical Small Animal and Clinical Treatment Plans

2014 ◽  
Vol 41 (6Part2) ◽  
pp. 93-94 ◽  
Author(s):  
S Price ◽  
S Yaddanapudi ◽  
D Rangaraj ◽  
E Izaguirre
Keyword(s):  
Small Animal ◽  
Clinical Treatment ◽  
Treatment Plans

Childhood Arthritis and Rheumatology Research Alliance Consensus Clinical Treatment Plans for Juvenile Dermatomyositis with Persistent Skin Rash

2016 ◽  
Vol 44 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Adam M. Huber ◽  
Susan Kim ◽  
Ann M. Reed ◽  
Ruy Carrasco ◽  
Brian M. Feldman ◽  
...  
Keyword(s):  
Skin Rash ◽  
Complete Resolution ◽  
Juvenile Dermatomyositis ◽  
Clinical Treatment ◽  
Muscle Disease ◽  
Nominal Group ◽  
Rheumatology Research ◽  
Childhood Arthritis ◽  
Treatment Plans ◽  
Research Alliance

Objective.Juvenile dermatomyositis (JDM) is the most common form of idiopathic inflammatory myopathy in children. While outcomes are generally thought to be good, persistence of skin rash is a common problem. The goal of this study was to describe the development of clinical treatment plans (CTP) for children with JDM characterized by persistent skin rash despite complete resolution of muscle involvement.Methods.The Childhood Arthritis and Rheumatology Research Alliance, a North American consortium of pediatric rheumatologists and other healthcare providers, used a combination of Delphi surveys and nominal group consensus meetings to develop CTP that reflected consensus on typical treatments for patients with JDM with persistent skin rash.Results.Consensus was reached on patient characteristics and outcome assessment. Patients should have previously received corticosteroids and methotrexate (MTX). Three consensus treatment plans were developed. Plan A added intravenous immunoglobulin (IVIG) if it was not already being used. Plan B added mycophenolate mofetil, while Plan C added cyclosporine. Continuation of previous treatments, including corticosteroids, MTX, and IVIG, was permitted in plans B and C.Conclusion.Three consensus CTP were developed for use in children with JDM and persistent skin rash despite complete resolution of muscle disease. These CTP reflect typical treatment approaches and are not to be considered treatment recommendations or standard of care. Using prospective data collection and statistical methods to account for nonrandom treatment assignment, it is expected that these CTP will be used to allow treatment comparisons, and ultimately determine the best treatment for these patients.

scholarly journals Optimisation of a composite difference metric for prompt error detection in real-time portal dosimetry of simulated volumetric modulated arc therapy

2021 ◽  
Vol 94 (1120) ◽  
pp. 20201014
Author(s):  
James L Bedford ◽  
Ian M Hanson
Keyword(s):  
Real Time ◽  
Error Detection ◽  
Volumetric Modulated Arc Therapy ◽  
Portal Dosimetry ◽  
Arc Therapy ◽  
Aperture Opening ◽  
Treatment Plans ◽  
Portal Images ◽  
The Individual ◽  
Individual Metrics

Objectives: In real-time portal dosimetry, thresholds are set for several measures of difference between predicted and measured images, and signals larger than those thresholds signify an error. The aim of this work is to investigate the use of an additional composite difference metric (CDM) for earlier detection of errors. Methods: Portal images were predicted for the volumetric modulated arc therapy plans of six prostate patients. Errors in monitor units, aperture opening, aperture position and path length were deliberately introduced into all 180 segments of the treatment plans, and these plans were delivered to a water-equivalent phantom. Four different metrics, consisting of central axis signal, mean image value and two image difference measures, were used to identify errors, and a CDM was added, consisting of a weighted power sum of the individual metrics. To optimise the weights of the CDM and to evaluate the resulting timeliness of error detection, a leave-pair-out strategy was used. For each combination of four patients, the weights of the CDM were determined by an exhaustive search, and the result was evaluated on the remaining two patients. Results: The median segment index at which the errors were identified was 87 (range 40–130) when using all of the individual metrics separately. Using a CDM as well as multiple separate metrics reduced this to 73 (35–95). The median weighting factors of the four metrics constituting the composite were (0.15, 0.10, 0.15, 0.00). Due to selection of suitable threshold levels, there was only one false positive result in the six patients. Conclusion: This study shows that, in conjunction with appropriate error thresholds, use of a CDM is able to identify increased image differences around 20% earlier than the separate measures. Advances in knowledge: This study shows the value of combining difference metrics to allow earlier detection of errors during real-time portal dosimetry for volumetric modulated arc therapy treatment.

35 Monte Carlo dose calculation of VMAT clinical treatment plans for Novalis TrueBeam STx linac using PRIMO

2018 ◽  
Vol 56 ◽  
pp. 20-21
Author(s):  
A. Sottiaux ◽  
V. Baltieri ◽  
A. Monseux ◽  
C. Leclercq ◽  
D. Vanache ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Dose Calculation ◽  
Clinical Treatment ◽  
Treatment Plans ◽  
Monte Carlo Dose Calculation

Retrospective analysis of portal dosimetry pre-treatment quality assurance of intracranial SRS/SRT VMAT treatment plans

2021 ◽  
pp. 1-13
Author(s):  
Ernest Osei ◽  
Sarah Graves ◽  
Johnson Darko
Keyword(s):  
Quality Assurance ◽  
Retrospective Analysis ◽  
Low Dose ◽  
Treatment Quality ◽  
Patient Specific ◽  
Portal Dosimetry ◽  
Treatment Plans ◽  
The Mean ◽  
Pre Treatment ◽  
Action Levels

Abstract Background: The complexity associated with the treatment planning and delivery of stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) volumetric modulated arc therapy (VMAT) plans which employs continuous dynamic modulation of dose rate, field aperture and gantry speed necessitates diligent pre-treatment patient-specific quality assurance (QA). Numerous techniques for pre-treatment VMAT treatment plans QA are currently available with the aid of several different devices including the electronic portal imager (EPID). Although several studies have provided recommendations for gamma criteria for VMAT pre-treatment QA, there are no specifics for SRS/SRT VMAT QA. Thus, we conducted a study to evaluate intracranial SRS/SRT VMAT QA to determine clinical action levels for gamma criteria based on the institutional estimated means and standard deviations. Materials and methods: We conducted a retrospective analysis of 118 EPID patient-specific pre-treatment QA dosimetric measurements of 47 brain SRS/SRT VMAT treatment plans using the integrated Varian solution (RapidArcTM planning, EPID and Portal dosimetry system) for planning, delivery and EPID QA analysis. We evaluated the maximum gamma (γmax), average gamma (γave) and percentage gamma passing rate (%GP) for different distance-to-agreement/dose difference (DTA/DD) criteria and low-dose thresholds. Results: The gamma index analysis shows that for patient-specific SRS/SRT VMAT QA with the portal dosimetry, the mean %GP is ≥98% for 2–3 mm/1–3% and Field+0%, +5% and +10% low-dose thresholds. When applying stricter spatial criteria of 1 mm, the mean %GP is >90% for DD of 2–3% and ≥88% for DD of 1%. The mean γmax ranges: 1·32 ± 1·33–2·63 ± 2·35 for 3 mm/1–3%, 1·57 ± 1·36–2·87 ± 2·29 for 2 mm/1–3% and 2·36 ± 1·83–3·58 ± 2·23 for 1 mm/1–3%. Similarly the mean γave ranges: 0·16 ± 0·06–0·19 ± 0·07 for 3 mm/1–3%, 0·21 ± 0·08–0·27 ± 0·10 for 2 mm/1–3% and 0·34 ± 0·14–0·49 ± 0·17 for 1 mm/1–3%. The mean γmax and mean γave increase with increased DTA and increased DD for all low-dose thresholds. Conclusions: The establishment of gamma criteria local action levels for SRS/SRT VMAT pre-treatment QA based on institutional resources is imperative as a useful tool for standardising the evaluation of EPID-based patient-specific SRS/SRT VMAT QA. Our data suggest that for intracranial SRS/SRT VMAT QA measured with the EPID, a stricter gamma criterion of 1 mm/2% or 1 mm/3% with ≥90% %GP could be used while still maintaining an in-control QA process with no extra burden on resources and time constraints.

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