Multi‐institution validation of a new high spatial resolution diode array for SRS and SBRT plan pretreatment quality assurance

Rose, Mark; Tirpak, L; Casteren, Kristin Van; Zack, Jeff; Simon, Tom; Schoenfeld, A; Simon, William E.

doi:10.1002/mp.14153

Cited by 48 publications

(92 citation statements)

References 99 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many of these systems are unable to deliver true composite treatment plans so a failed QA measurement will do little to guide the practitioners on how to proceed and may potentially lead to looser QA passing tolerance levels. 14,15,17…”

Section: C Electronic Phantomsmentioning

confidence: 99%

“…There are a number of electronic phantom devices that have been developed over the years and have had much success in the patient-specific verification of IMRT, VMAT 19 and more recently SRS. 15,17,18,20 These devices utilize either diodes or ion chambers to perform measurements and give immediate results. The immediacy of the results makes them an attractive option for routine quality assurance measurements.…”

Section: C Electronic Phantomsmentioning

confidence: 99%

“…Various attempts have been made utilizing different commercial and non-commercial system to varying degrees of success. [10][11][12][13][14][15][16][17][18][19][20][21][22] Some of the more common and current methods and their limitations will be briefly discussed (Figs. 1-7).…”

Section: Introductionmentioning

confidence: 99%

“…Many of the currently available phantom systems have limited capacity to measure small and arbitrarily placed target volumes. Various attempts have been made utilizing different commercial and non‐commercial system to varying degrees of success 10–22 . Some of the more common and current methods and their limitations will be briefly discussed (Figs.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The development and testing of a novel spherical radiotherapy phantom system for the commissioning and patient‐specific quality assurance of mono‐isocentric multiple mets SRS plans

McKenna

2020

Medical Physics

View full text Add to dashboard Cite

Purpose To develop a single radiotherapy phantom system capable of performing both patient‐specific quality assurance (QA) measurements and commissioning measurements for mono‐isocentric LinAc‐based stereotactic radiosurgery (“mLSRS”) treatment plans. Methods DesignA 20‐cm diameter spherical phantom was designed which contained within it a film cartridge. The surface of the sphere was machined to display a set of angular markings at both the equator and the meridian representing a spherical coordinate system. A stand was designed which allows for free rotation about any vector passing through the center of the sphere. A program was created using Python 3 to: (a) Compute the measurement setup necessary to intersect exactly one film plane with three user specified dicom points contained within the QA plan; (b) Extract the intersection dose plane from the three dimensional DICOM dose file and; (c) Generate a synthetic computed tomography (CT) in the exact measurement geometry which is subsequently used for phantom positioning during the QA measurement. Testing To assess the functionality of the phantom system dynamic conformal arc mLSRS plans that were generated by a clinically commissioned multiple metastasis treatment planning system (BrainLab Elements version 2.0) using patient‐specific data. A total of seven patient plans were created that contained a total of 31 targets { = (0.382 ± 0.534) cc: Range [0.051, 2.05] cc, = (30 ± 16) mm: Range[0, 55] mm} 27 of which were directly measured with film and analyzed. Each planned isocenter was mapped to the phantom’s center and the dose was recomputed. From the phantom dose distribution dicom points of interest were selected in sets of three and input into the provided software. The software computed the plane that intersects with the entered three points and instructed the user on the setup geometry to place the film in the intersecting plane. The software then generated a synthetic CT scan with embedded fiducial markers rotated into the setup orientation. This CT was then used as the setup reference image in ExacTrac image guidance system (tolerance 0.7 mm & 0.5deg). All plans were delivered on a Varian Truebeam linear accelerator with HDMLC, Exactrac and a 6 degree of freedom couch. After delivery of each test plan a 10 × 10 reference field was delivered to a known dose approximately equal to the maximum dose contained within the plan for film calibration. The test film was scanned simultaneously with the 10 × 10 reference film and a film that received zero dose using an Epson 10000XL flatbed scanner after waiting 24 hours. The test film was scaled according to the reference film and analyzed via the gamma analysis (3%, 1 mm, 10%) implemented in Ashland Film QA Pro software. Results The spherical phantom system was able to perform validation measurements on a variety of patient‐specific plan geometries. The average gamma pass‐rate γ(3%, 1 mm,10%) for all measurements was 96.7% (σ = 3.6%). Conclusions A novel spherical radiotherapy phantom s...

show abstract

Section: C Electronic Phantomsmentioning

confidence: 99%

Section: C Electronic Phantomsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The development and testing of a novel spherical radiotherapy phantom system for the commissioning and patient‐specific quality assurance of mono‐isocentric multiple mets SRS plans

McKenna

2020

Medical Physics

View full text Add to dashboard Cite

show abstract

“…The array has a measurable area of 77 mm × 77 mm. 12 The SRS MapCHECK can be inserted into the Sun Nuclear StereoPHAN which holds the SRS MapCHECK over the superior end of the couch. The StereoPHAN is a cylindrical PMMA phantom which is shaped in order to mimic the shape of a head.…”

Section: Introductionmentioning

confidence: 99%

Patient‐specific dose quality assurance of single‐isocenter multiple brain metastasis stereotactic radiosurgery using PTW Octavius 4D

McCulloch¹,

Pawlowski²,

Kirby³

et al. 2020

J Applied Clin Med Phys

View full text Add to dashboard Cite

Purpose Single‐isocenter multiple brain metastasis stereotactic radiosurgery is an efficient treatment modality increasing in clinical practice. The need to provide accurate, patient‐specific quality assurance (QA) for these plans is met by several options. This study reviews some of these options and explores the use of the Octavius 4D as a solution for patient‐specific plan quality assurance. Methods The Octavius 4D Modular Phantom (O4D) with the 1000 SRS array was evaluated in this study. The array consists of 977 liquid‐filled ion chambers. The center 5.5 cm × 5.5 cm area has a detector spacing of 2.5 mm. The ability of the O4D to reconstruct three‐dimensional (3D) dose was validated against a 3D gel dosimeter, ion chamber, and film measurements. After validation, 15 patients with 2–11 targets had their plans delivered to the phantom. The criteria used for the gamma calculation was 3%/1 mm. The portion of targets which were measurable by the phantom was countable. The accompanying software compiled the measured doses allowing each target to be counted from the measured dose distribution. Results Spatial resolution was sufficient to verify the high dose distributions characteristic of SRS. Amongst the 15 patients there were 74 targets. Of the 74 targets, 61 (82%) of them were visible on the measured dose distribution. The average gamma passing rate was 99.3% (with sample standard deviation of 0.68%). Conclusions The high resolution provided by the O4D with 1000 SRS board insert allows for very high‐resolution measurement. This high resolution in turn can allow for high gamma passing rates. The O4D with the 1000 SRS array is an acceptable method of performing quality assurance for single‐isocenter multiple brain metastasis SRS.

show abstract

Sensitivity and specificity analysis of 2D small field measurement array: Patient‐specific quality assurance of small target treatments and spatially fractionated radiotherapy

Baños-Capilla

Lago-Martín

Gil³

et al. 2021

J Applied Clin Med Phys

View full text Add to dashboard Cite

The aim of this paper is to describe the tests carried out on a SRSMapCheck array, to verify its reliability and sensitivity for quality assurance (QA) of high gradient treatments as an alternative system to the use of high spatial resolution detectors, such as gafchromic film, whose processing requires meticulous and time-consuming procedures. Methods: In an initial step, general functionality tests were carried out to verify that the equipment meets the manufacturer's specifications. A study of the accuracy of the application of correction factors to compensate for variation in detector response due to dose rate, field size and beam angle incidence has been included. Besides, to assess the ability of the array to detect inaccurately delivered treatments, systematic errors corresponding to the deviation in the position of the leaves and the accuracy of the gantry position, have been introduced. Based on these results, an estimate of sensitivity and specificity values of the device has been completed. The final step included a study applied to high gradient treatment for real cases of spatially fractionated radiotherapy, where the results of SRSMapCheck measurements have been compared with gafchromic films. Results: General commissioning tests meet the manufacturer's specifications. dose rate (DR) response variation is better than 1.5% and for DR above 50 MU/min better than 1%. The results for beam incidences are better than 1% for all gantry angles, including beam incidences parallel to the array. Field size response differences are within the range of ±1% for sizes up to 2 × 2 cm 2 , with a maximum value obtained of 3.5%, for 1 × 1 cm 2 . From the systematic error study, using a Gamma function Γ (2%, 2 mm), the detector presents a high specificity with a value greater than 90% at its lower limit, while its sensitivity has a moderate mean value of 81%. Sensitivity values increase above 86% when we apply a Gamma function Γ (2%, 1 mm) is applied. Finally, the study of actual cases comprises 17 patients, distributed into 11 lung tumors, 3 gynecological and 3 soft tissue tumors. The gafchromic film showed a lower passing rate with an average value of Γ (2%, 2 mm) = 94.1% compared to Γ (2%, 2 mm) = 98.6% reached by the measurements with the array.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

show abstract

Multi‐institution validation of a new high spatial resolution diode array for SRS and SBRT plan pretreatment quality assurance

Cited by 48 publications

References 99 publications

The development and testing of a novel spherical radiotherapy phantom system for the commissioning and patient‐specific quality assurance of mono‐isocentric multiple mets SRS plans

The development and testing of a novel spherical radiotherapy phantom system for the commissioning and patient‐specific quality assurance of mono‐isocentric multiple mets SRS plans

Patient‐specific dose quality assurance of single‐isocenter multiple brain metastasis stereotactic radiosurgery using PTW Octavius 4D

Sensitivity and specificity analysis of 2D small field measurement array: Patient‐specific quality assurance of small target treatments and spatially fractionated radiotherapy

Contact Info

Product

Resources

About