Evaluation of Dose Calculation Algorithms of Isogray Treatment Planning System Using Measurement in Heterogeneous Phantom

Golestani, Asiyeh; Houshyari, Mohammad; Mostaar, Ahmad; Arfaie, Ali Jabbari

doi:10.17795/rro-5320

Cited by 5 publications

(6 citation statements)

References 30 publications

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“…stated that the TPS cannot accurately calculate the dose in shoulder and penumbra regions [13]. However, other researchers, evaluating the accuracy of dose calculation by different TPSs, have confirmed the inaccuracy of these systems [27], the various calculation algorithms have different levels of inaccuracy [28]. Therefore, the assessment of these regions was made using the GAFCHROMIC EBT3 film as an independent tool.…”

Section: Discussionmentioning

confidence: 99%

An Empirical Transmitted EPID Dosimetry Method using a Back- Projection Algorithm

et al. 2019

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Background:The present study aimed to introduce a rapid transmission dosimetry through an electronic portal-imaging device (EPID) to achieve two-dimensional (2D) dose distribution for homogenous environments. Material and Methods: In this Phantom study, first, the EPID calibration curve and correction coefficients for field size were obtained from EPID and ionization chamber. Second, the EPID off-axis pixel response was measured, and the grey-scale image of the EPID was converted into portal dose image using the calibration curve. Next, the scattering contribution was calculated to obtain the primary dose. Then, by means of a verified back-projection algorithm and the Scatter-to-Primary dose ratio, a 2D dose distribution at the mid-plane was obtained. Results: The results obtained from comparing the transmitted EPID dosimetry to the calculated dose, using commercial treatment planning system with gamma function while there is 3% dose difference and 3mm distance to agreement criteria, were in a good agreement. In addition, the pass rates of γ < 1 was 94.89% for the homogeneous volumes. Conclusion:Based on the results, the method proposed can be used in EPID dosimetry.

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Section: Discussionmentioning

confidence: 99%

An Empirical Transmitted EPID Dosimetry Method using a Back- Projection Algorithm

et al. 2019

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“…Golestani et al have investigated the accuracy of the dose by means of a TPS using different computational methods, and the error rate has reported to be <3%. [16] Furthermore, Miften et al have studied the dose distribution of tumor in the prostate, head, neck, and lungs using a TPS based on Clarkson and superposition algorithms. In the study, they found that the error rate was <4%.…”

Section: Discussionmentioning

confidence: 99%

A Novel Algorithm in Radiation Dosimetry of Regular and Irregular Treatment Fields

et al. 2019

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Background: The aim of this study was to design an algorithm for the calculation of monitor unit (MU) in a short time and high precision for different radiotherapy (RT) fields. Materials and Methods: The algorithm for calculating MU for the stated patients was designed in MATLAB software. To investigate the efficiency of this algorithm, 11 regular chest fields with the sizes of 7 cm × 7 cm up to 17 cm × 17 cm were considered, and the obtained MUs were compared with MUs of 13 patients which were calculated with a “hand calculation” which is used in some RT centers for the aforementioned fields. Results: The maximum percentage of calculation errors of regular fields at the depths of 4 and 10 cm were 1 and 0.8, respectively. The maximum and minimum percentage of calculation errors in irregular fields was 3 and 0.9, respectively. Furthermore, the maximum and minimum errors were 8.8 and 0.14, respectively. In addition, relative percentages of the MUs for irregular fields of chest and supraclavicular were 1.63 and 1.01, respectively. Conclusion: Calculation of MUs is suggested to be performed with the novel proposed algorithm, due to reduce the treatment time, and also provide high accuracy and precision compared to hand calculation.

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“…The dose distribution is much more complex in the region of heterogeneous tissues, particularly in small fields and the size of the discrepancy escalates [ 5 , 7 ]. A low-density medium, such as the lung in a small field usually leads to challengingly estimating dose.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Radiation Treatment Planning Algorithms in IMRT and VMAT: A Comparative Dosimetric Study in Lung Equivalent Heterogeneous Medium

2023

J Biomed Phys Eng

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Background: In Radiotherapy, computation of dose is important since in a small field with heterogeneity, dose is usually computed with discrepancies. Objective: The present study was aimed to evaluate the dosimetry of treatment planning algorithms in lung equivalent heterogeneous medium for Volumetric Modulated Arc Therapy (VMAT) with step and shoot Intensity-Modulated Radiation Therapy (ss-IMRT), and dynamic Intensity-Modulated Radiation Therapy (d-IMRT). Material and Methods: In this experimental study, Computerized Imaging Reference System (CIRS) phantom was used with an inhomogeneous Racemosa wood cylinder for two types of tumors, namely, Left Lung Central Tumor (LCT) and Left Lung Peripheral Tumor (LPT) in the CIRS left lung cavity. The computed tomography (CT) datasets were employed with the generation of VMAT, d-IMRT and ss-IMRT plans for the LCT and LPT irradiated with 6 MV photon beams. In this study, the accuracy and efficacy of two algorithms: Monte Carlo (MC) and the Pencil Beam (PB), from the Monaco treatment planning system (TPS), were tested by using Gafchromic EBT3 films and CIRS thorax phantom. Results: Regardless of treatment techniques, both algorithms exhibited higher divergence in LPT than LCT. In both LCT and LPT, the highest deviation was near the tumor-lung junction. However, the deviation was higher in the PB algorithm than MC algorithm, with a minimally acceptable variation of -0.8%. Conclusion: The MC algorithm shows more consistency for EBT3 measured dose in lung equivalent heterogeneous medium. However, accurate dose predictions are complicated due to electronic disequilibrium within and at the interface of inhomogeneity. These constraints may cause variations from the anticipated outcomes of the treatments.

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Evaluation of Dose Calculation Algorithms of Isogray Treatment Planning System Using Measurement in Heterogeneous Phantom

Cited by 5 publications

References 30 publications

An Empirical Transmitted EPID Dosimetry Method using a Back- Projection Algorithm

An Empirical Transmitted EPID Dosimetry Method using a Back- Projection Algorithm

A Novel Algorithm in Radiation Dosimetry of Regular and Irregular Treatment Fields

Evaluation of Radiation Treatment Planning Algorithms in IMRT and VMAT: A Comparative Dosimetric Study in Lung Equivalent Heterogeneous Medium

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