Quality control test for electronic portal imaging device using QC-3 phantom with PIPSpro

Rout, Birendra Kumar; Shekar, Mukka Chandra; Kumar, Akhilesh; Ramesh, Kondapalli Kesava Durga

doi:10.14319/ijcto.0204.9

Cited by 5 publications

(6 citation statements)

References 15 publications

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“…Gd2O2S:Tb is utilized in EPID systems [2], [11], [12] since it efficiently absorbs the X-ray photons and converts the absorbed X-ray energy to optical photon energy. The optical photons that escape the phosphor part of the EPID are subsequently absorbed into the silicon pixelated array and finally converted to bit values.…”

Section: Optical Photons Creation and Propagationmentioning

confidence: 99%

“…The assessment of the imaging performance of an EPID is performed with dedicated phantoms and methods as part of the quality control procedure [9], [10]. The phantoms may contain areas of low and high atomic number materials of different shapes so that parameters like image contrast, resolution and noise, to be evaluated [11], [12]. In this work the first step in the design of a phantom for image contrast assessment is presented.…”

Section: Introductionmentioning

confidence: 99%

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Towards the Implementation of a Phantom for the Low Contrast Evaluation of Electronic Portal Imaging Detectors (Epid): A Theoretical Study

Kalyvas,

Tzomakas,

Peppa

et al. 2023

RAP Conference Proceedings

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Electronic Portal Imaging Systems (EPIDs) are used in Radiotherapy treatment as part of the patient positioning verification check and for portal dosimetry purposes. The quality control of the imaging performance of an EPID is performed with dedicated phantoms. In this work, an examination through Monte Carlo (MC) simulation is presented in order to determine an appropriate step wedge phantom configuration for measuring low contrast differences in EPIDs. The PENELOPE based MC software package PenEasy was used. A simple geometry of a narrow cone beam with a cross section of 0.00053 cm 2 at 100 cm distance was assumed. A 2 MeV beam was considered to impinge on a 4 cm water equivalent phantom in conjunction with a metal sheet of Pb, Al, Fe or W positioned at 80 cm distance. At 100 cm distance a Gd2O2S:Tb scintillator, as part of an EPID responsible for detecting X-rays was assumed. The Gd2O2S:Tb thicknesses considered were 0.02cm and 0.03 cm. All the metal thicknesses were allowed to range from 0.1 cm to 1.5 cm per 0.1 cm step. The optical photons escaping to the Gd2O2S:Tb output were calculated by an analytical formula for each metal thickness. Hence, if a wedge metallic pattern from 0.1 cm to 1.5 cm is assumed to be constructed, then the optical photon output originating from each step, as well as the signal contrast between two steps would be known. It was found that a combination of Pb, Fe and W materials can be used for a step wedge phantom design.

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Section: Optical Photons Creation and Propagationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Towards the Implementation of a Phantom for the Low Contrast Evaluation of Electronic Portal Imaging Detectors (Epid): A Theoretical Study

Kalyvas,

Tzomakas,

Peppa

et al. 2023

RAP Conference Proceedings

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“…The QC3 phantom integrated with PIPSpro™ software (Standard Imaging, Middleton, WI) is the other popular QA tool. 35 It contains a series of high-contrast bar patterns with spatial frequencies of 0.1, 0.2, 0.25, 0.4, and 0.75 lp/mm and six uniform regions made from lead, aluminum, or plastic of different thicknesses. In measurement, the phantom was placed on the surface of the EPID detector at 45 • angle with respect to the axis to prevent spatial aliasing.…”

Section: D Sensitivity Analysismentioning

confidence: 99%

Use of local noise power spectrum and wavelet analysis in quantitative image quality assurance for EPIDs

et al. 2016

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“…For the patient specific pretreatment quality assurance for s-IMRT, d-IMRT and VMAT were performed systematically twice with 2D array (PTW, Freiburg) and a-Si EPID. [21][22][23][24] These detectors worked in the integrated mode, so the fluence delivered with each and every beam and segment was accumulated in a single frame. The measured fluence was compared with the TPS calculated fluence.…”

Section: Treatment Planning Optimization and Pre-treatment Verificatmentioning

confidence: 99%

“…It is a popular tool amongst the modern quality control techniques. [18][19] Besides positional verification [20][21] and quality control of linac 19,[22][23]24 , several studies have validated a-Si EPID for patient specific dosimetry.…”

Section: Introductionmentioning

confidence: 99%

Consistency analysis for the performance of planar detector systems used in advanced radiotherapy

Jassal

Sarkar

Munshi

et al. 2014

Int J Cancer Ther Oncol

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Purpose:To evaluate the performance linked to the consistency of a-Si EPID and ion-chamber array detectors for dose verification in advanced radiotherapy. Methods: Planar measurements were made for 250 patients using an array of ion chamber and a-Si EPID. For pre-treatment verification, the plans were generated on the phantom for re-calculation of doses. The γ-evaluation method with the criteria: dose-difference (DD) ≤ 3% and distance-to-agreement (DTA) ≤ 3 mm was used for the comparison of measurements. Also, the central axis (CAX) doses were measured using 0.125cc ion chamber and were compared with the central chamber of array and central pixel correlated dose value from EPID image. Two types of statistical approaches were applied for the analysis. Conventional statistics used analysis of variance (ANOVA) and unpaired t-test to evaluate the performance of the detectors. And statistical process control (SPC) was utilized to study the statistical variation for the measured data. Control charts (CC) based on an average ( ), standard deviation ( ̅ ) and exponentially weighted moving averages (EWMA) were prepared. The capability index (Cpm) was determined as an indicator for the performance consistency of the two systems. Results: Array and EPID measurements had the average gamma pass rates as 99.9% ± 0.15% and 98.9% ± 1.06% respectively. For the point doses, the 0.125cc chamber results were within 2.1% ± 0.5% of the central chamber of the array. Similarly, CAX doses from EPID and chamber matched within 1.5% ± 0.3%. The control charts showed that both the detectors were performing optimally and all the data points were within ± 5%. EWMA charts revealed that both the detectors had a slow drift along the mean of the processes but was found well within ± 3%. Further, higher Cpm values for EPID demonstrate its higher efficiency for radiotherapy techniques. Conclusion: The performances of both the detectors were seen to be of high quality irrespective of the radiotherapy technique. Higher Cpm values for EPID indicate its higher efficiency than array. FIG. 2(a-c): ̅ control charts for s-IMRT, d-IMRT and VMAT QA measurements by a-Si EPID and array FIG. 3: EWMA control charts for s-IMRT, d-IMRT and VMAT QA measurements by a-Si EPID and array

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Quality control test for electronic portal imaging device using QC-3 phantom with PIPSpro

Cited by 5 publications

References 15 publications

Towards the Implementation of a Phantom for the Low Contrast Evaluation of Electronic Portal Imaging Detectors (Epid): A Theoretical Study

Towards the Implementation of a Phantom for the Low Contrast Evaluation of Electronic Portal Imaging Detectors (Epid): A Theoretical Study

Use of local noise power spectrum and wavelet analysis in quantitative image quality assurance for EPIDs

Consistency analysis for the performance of planar detector systems used in advanced radiotherapy

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