Improvement of off‐axis <scp>SABR</scp> plan verification results by using adapted dose reconstruction algorithms for the Octavius 4D system

Jeevanandam, Prakash; Agnew, Christina; Irvine, Denise M.; McGarry, Conor K.

doi:10.1002/mp.12805

Cited by 5 publications

(3 citation statements)

References 32 publications

(73 reference statements)

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“…A passing rate of more than 90% was observed for both 2%/2 mm and 3%/3 mm criteria. The SABR plans were verified using the traditional 2%/2 mm criterion, in line with previous studies 51–53 . Our results, presented in Figures 6–8, show that the profile differences between measured and calculated doses were within 2%.…”

Section: Discussionsupporting

confidence: 89%

“…The SABR plans were verified using the traditional 2%/2 mm criterion, in line with previous studies. [51][52][53] Our results, presented in Figures 6-8, show that the profile differences between measured and calculated doses were within 2%. For the VMAT plan, the conventional 2D array detector MapCHECK2 showed a passing rate of over 90% for both 2%/2 mm and 3%/3 mm criteria, consistent with our previous practice.…”

Section: Discussionsupporting

confidence: 57%

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Development of a quasi‐3D dosimeter using radiochromic plastic for patient‐specific quality assurance

et al. 2023

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BackgroundPatient‐specific QA verification ensures patient safety and treatment by verifying radiation delivery and dose calculations in treatment plans for errors. However, a two‐dimensional (2D) dose distribution is insufficient for detecting information on the three‐dimensional (3D) dose delivered to the patient. In addition, 3D radiochromic plastic dosimeters (RPDs) such as PRESAGE® represent the volume effect in which the dosimeters have different sensitivities according to the size of the dosimeters. Therefore, to solve the volume effect, a Quasi‐3D dosimetry system was proposed to perform patient‐specific QA using predetermined‐sized and multiple RPDs.PurposeFor patient‐specific quality assurance (QA) in radiation treatment, this study aims to assess a quasi‐3D dosimetry system using an RPD.MethodsGamma analysis was performed to verify the agreement between the measured and estimated dose distributions of intensity‐modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT). We fabricated cylindrical RPDs and a quasi‐3D dosimetry phantom. A practicability test for a pancreatic patient utilized a quasi‐3D dosimetry device, an in‐house RPD, and a quasi‐3D phantom. The dose distribution of the VMAT design dictated the placement of nine RPDs. Moreover, a 2D diode array detector was used for 2D gamma analysis (MapCHECK2). The patient‐specific QA was performed for IMRT, VMAT, and stereotactic ablative radiotherapy (SABR) in 20 prostate and head‐and‐neck patients. For each patient, six RPDs were positioned according to the dose distribution. VMAT SABR and IMRT/VMAT plans employed a 2%/2 mm gamma criterion, whereas IMRT/VMAT plans used a 3%/2 mm gamma criterion, a 10% threshold value, and a 90% passing rate tolerance. 3D gamma analysis was conducted using the 3D Slicer software.ResultsThe average gamma passing rates with 2%/2 mm and 3%/3 mm criteria for relative dose distribution were 91.6% ± 1.4% and 99.4% ± 0.7% for the 3D gamma analysis using the quasi‐3D dosimetry system, respectively, and 97.5% and 99.3% for 2D gamma analysis using MapCHECK2, respectively. The 3D gamma analysis for patient‐specific QA of 20 patients showed passing rates of over 90% with 2%/2 mm, 3%/2 mm, and 3%/3 mm criteria.ConclusionsThe quasi‐3D dosimetry system was evaluated by performing patient‐specific QAs with RPDs and quasi‐3D phantom. The gamma indices for all RPDs showed more than 90% for 2%/2 mm, 3%/2 mm, and 3%/3 mm criteria. We verified the feasibility of a quasi‐3D dosimetry system by performing the conventional patient‐specific QA with the quasi‐3D dosimeters.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 57%

Development of a quasi‐3D dosimeter using radiochromic plastic for patient‐specific quality assurance

et al. 2023

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“…This arrangement diminishes clearance issues, spare couch motions and allows plans with one or more fullarc rotations. [17][18][19][20][21][22] Regarding the beam field-of-view, the relative target position in this condition describes a wider oscillation than that with a more centred target. Thus, the MLC leaves are forced to move in wider ranges, and the subsequent secondary collimation will encompass a wider area, assuming a static arrangement.…”

Section: Introductionmentioning

confidence: 85%

Dosimetrical assessment of jaw tracking technique in volumetric modulated arc therapy for a sample of patients with lateralised targets

Moreno¹,

Almada²,

Andino³

et al. 2023

J Radiother Pract

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Introduction: In modulated radiotherapy treatments with the jaw tracking technique (JTT), the collimator jaws can dynamically follow the multileaf collimator apertures and reduce radiation leakage. This reduction protects normal tissue from unwanted doses. Previous research has highlighted the importance of defining which patients will benefit most from JTT. Besides, some authors have expressed their concerns about possible increases in monitor units (MUs). Treatments of patients with peripheral targets and isocentre located in the patient’s midline are of particular interest. The current work assessed the effect of JTT on these cases. Methods: JTT plans for thirty-two patients were compared to plans with the static jaws technique. The volumes of normal tissue receiving 5 Gy (V5), 10 Gy (V10) and 20 Gy (V20), mean dose (Dmean), target coverage parameters D95, D2% and Paddick’s conformity index (PCI) were compared. MUs were also registered for comparisons. The decrease in the jaws opening with JTT was correlated to the decrease in dose values in normal tissue. Results: Small decreases were observed in D95 and in D2% values, without statistical significance. A 5% average decrease in PCI values was noticed as well as significant decreases in V5, V10 and Dmean values, 9% on average. A 3% decrease in V20 was also observed. The number of MUs decreased by 2%. A significant correlation was found between the reduction of the secondary collimation opening areas and the dose delivered to normal tissue. Conclusions: JTT technique improved normal tissue protection in volumetric modulated arc therapy treatments for the patients included in the present study.

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Patient specific evaluation of breathing motion induced interplay effects

et al. 2023

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Improvement of off‐axis SABR plan verification results by using adapted dose reconstruction algorithms for the Octavius 4D system

Cited by 5 publications

References 32 publications

Development of a quasi‐3D dosimeter using radiochromic plastic for patient‐specific quality assurance

Development of a quasi‐3D dosimeter using radiochromic plastic for patient‐specific quality assurance

Dosimetrical assessment of jaw tracking technique in volumetric modulated arc therapy for a sample of patients with lateralised targets

Patient specific evaluation of breathing motion induced interplay effects

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