Routine IMRT verification by means of an automated Monte Carlo simulation system

Leal, Antonio; Sánchez‐Doblado, F.; Arráns, R.; Roselló, J.; Pavón, Ester Carrasco; Lagáres, J.I.

doi:10.1016/s0360-3016(03)00067-1

Cited by 63 publications

(49 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…On the one hand, an independent verification of the TPS dose calculations should be carried out. One way to fulfill this requirement consists of the application of Monte Carlo calculations for the independent verification of the treatment plan (9) . The main limitation in the application of these techniques is the calculation time.…”

Section: Introductionmentioning

confidence: 99%

Dosimetric validation and clinical implementation of two 3D dose verification systems for quality assurance in volumetric‐modulated arc therapy techniques

Clemente-Gutiérrez

Perez-Vara

2015

J Applied Clin Med Phys

View full text Add to dashboard Cite

A pretreatment quality assurance program for volumetric techniques should include redundant calculations and measurement‐based verifications. The patient‐specific quality assurance process must be based in clinically relevant metrics. The aim of this study was to show the commission, clinical implementation, and comparison of two systems that allow performing a 3D redundant dose calculation. In addition, one of them is capable of reconstructing the dose on patient anatomy from measurements taken with a 2D ion chamber array. Both systems were compared in terms of reference calibration data (absolute dose, output factors, percentage depth‐dose curves, and profiles). Results were in good agreement for absolute dose values (discrepancies were below 0.5%) and output factors (mean differences were below 1%). Maximum mean discrepancies were located between 10 and 20 cm of depth for PDDs (‐2.7%) and in the penumbra region for profiles (mean DTA of 1.5 mm). Validation of the systems was performed by comparing point‐dose measurements with values obtained by the two systems for static, dynamic fields from AAPM TG‐119 report, and 12 real VMAT plans for different anatomical sites (differences better than 1.2%). Comparisons between measurements taken with a 2D ion chamber array and results obtained by both systems for real VMAT plans were also performed (mean global gamma passing rates better than 87.0% and 97.9% for the 2%/2 mm and 3%/3 mm criteria). Clinical implementation of the systems was evaluated by comparing dose‐volume parameters for all TG‐119 tests and real VMAT plans with TPS values (mean differences were below 1%). In addition, comparisons between dose distributions calculated by TPS and those extracted by the two systems for real VMAT plans were also performed (mean global gamma passing rates better than 86.0% and 93.0% for the 2%/2 mm and 3%/3 mm criteria). The clinical use of both systems was successfully evaluated.PACS numbers: 87.56.Fc, 87.56.‐v, 87.55.dk, 87.55.Qr, 87.55.‐x, 07.57.Kp, 85.25.Pb

show abstract

Section: Introductionmentioning

confidence: 99%

Dosimetric validation and clinical implementation of two 3D dose verification systems for quality assurance in volumetric‐modulated arc therapy techniques

Clemente-Gutiérrez

Perez-Vara

2015

J Applied Clin Med Phys

View full text Add to dashboard Cite

show abstract

“…The use of Monte Carlo has been proposed by several authors, 29 , 30 but we avoided that for two reasons: i) we believe the goal of the independent dose calculator is to act as a QA tool looking for major errors instead of determining the accuracy of the commissioned treatment planning system algorithm and beam model; ii) from an efficiency aspect, the time required to compute independent dose calculations with Monte Carlo are prohibitively long.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the efficiency and effectiveness of independent dose calculation followed by machine log file analysis against conventional measurement based IMRT QA

Sun

Rangaraj

Boddu

et al. 2012

J Applied Clin Med Phys

View full text Add to dashboard Cite

Experimental methods are commonly used for patient‐specific IMRT delivery verification. There are a variety of IMRT QA techniques which have been proposed and clinically used with a common understanding that not one single method can detect all possible errors. The aim of this work was to compare the efficiency and effectiveness of independent dose calculation followed by machine log file analysis to conventional measurement‐based methods in detecting errors in IMRT delivery. Sixteen IMRT treatment plans (5 head‐and‐neck, 3 rectum, 3 breast, and 5 prostate plans) created with a commercial treatment planning system (TPS) were recalculated on a QA phantom. All treatment plans underwent ion chamber (IC) and 2D diode array measurements. The same set of plans was also recomputed with another commercial treatment planning system and the two sets of calculations were compared. The deviations between dosimetric measurements and independent dose calculation were evaluated. The comparisons included evaluations of DVHs and point doses calculated by the two TPS systems. Machine log files were captured during pretreatment composite point dose measurements and analyzed to verify data transfer and performance of the delivery machine. Average deviation between IC measurements and point dose calculations with the two TPSs for head‐and‐neck plans were 1.2±1.3% and 1.4±1.6%, respectively. For 2D diode array measurements, the mean gamma value with 3% dose difference and 3 mm distance‐to‐agreement was within 1.5% for 13 of 16 plans. The mean 3D dose differences calculated from two TPSs were within 3% for head‐and‐neck cases and within 2% for other plans. The machine log file analysis showed that the gantry angle, jaw position, collimator angle, and MUs were consistent as planned, and maximal MLC position error was less than 0.5 mm. The independent dose calculation followed by the machine log analysis takes an average 47±6 minutes, while the experimental approach (using IC and 2D diode array measurements) takes an average about 2 hours in our clinic. Independent dose calculation followed by machine log file analysis can be a reliable tool to verify IMRT treatments. Additionally, independent dose calculations have the potential to identify several problems (heterogeneity calculations, data corruptions, system failures) with the primary TPS, which generally are not identifiable with a measurement‐based approach. Additionally, machine log file analysis can identify many problems (gantry, collimator, jaw setting) which also may not be detected with a measurement‐based approach. Machine log file analysis could also detect performance problems for individual MLC leaves which could be masked in the analysis of a measured fluence.PACS numbers: 87.53.Bn, 87.55.Qr, 87.55.km, 87.57.Uq

show abstract

“…Ma et al [26] used the particle dependent weighting factor method, applying different weights to each particle according to the integral linear attenuation encountered by a ray passing through the beam modifiers. Leal et al [27] and Seco et al [28] adopted the full MC simulation strategy, simulating the particle tracking through all the components of the unit and implementing the Static Component Simulation (SCS) as described by Shih et al [29] to reproduce a step-and-shoot IMRT delivery. Liu et al [30] firstly described the PositionProbability Sampling (PPS) method, which faces the unit component motion, such as the MLC leaves, from a probabilistic point of view.…”

Section: Introductionmentioning

confidence: 99%

Primo software as a tool for Monte Carlo simulations of intensity modulated radiotherapy: A feasibility study

et al. 2016

View full text Add to dashboard Cite

Background: IMRT provides higher dose conformation to the target and dose sparing to surrounding tissues than 3DCRT. Monte Carlo method in Medical Physics is not a novelty to approach dosimetric problems. A new PENELOPE based code named PRIMO recently was published. The most intriguing features of PRIMO are the user-friendly approach, the stand-alone property and the built-in definition of different linear accelerators models. Nevertheless, IMRT simulations are not yet implemented. Methods: A Varian Trilogy with a Millennium120 MLC and a Varian Novalis with 120HD MLC were studied. A RW3 multi-slab phantom was irradiated with Gafchromic films inserted between slabs. An Expression 10000XL scanner (Seiko Epson Corp., Nagano, Japan) was used to digitalize the films. PTW-Verisoft software using the global Gamma Function (2%, 2 mm) was used to compare simulated and experimental results. The primary beam parameters were adjusted to best match reference data previously obtained in a water phantom. Static MLC simulations were performed to validate the MLC models in use. Two Dynamic IMRT preliminary tests were performed with leaves moving with constant and variable speed. A further test of an in phantom delivery of a real IMRT field allowed simulating a clinical-like MLC modulation.

show abstract

Routine IMRT verification by means of an automated Monte Carlo simulation system

Cited by 63 publications

References 17 publications

Dosimetric validation and clinical implementation of two 3D dose verification systems for quality assurance in volumetric‐modulated arc therapy techniques

Dosimetric validation and clinical implementation of two 3D dose verification systems for quality assurance in volumetric‐modulated arc therapy techniques

Evaluation of the efficiency and effectiveness of independent dose calculation followed by machine log file analysis against conventional measurement based IMRT QA

Primo software as a tool for Monte Carlo simulations of intensity modulated radiotherapy: A feasibility study

Contact Info

Product

Resources

About