Dose calculation validation of a convolution algorithm in a solid water phantom

2021 ◽  
Vol 89 ◽  
pp. 193-199
Author(s):  
François Dubus ◽  
Nick Reynaert
Keyword(s):  
Dose Calculation ◽  
Water Phantom ◽  
Convolution Algorithm ◽  
Solid Water

scholarly journals Fast MCsquare-Based Independent Dose Verification Platform for Pencil Beam Scanning Proton Therapy

2021 ◽  
Vol 20 ◽  
pp. 153303382110330
Author(s):  
Chunbo Liu ◽  
Meng Wei Ho ◽  
Jiyeon Park ◽  
Wen Chien Hsi ◽  
Xiaoying Liang ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Treatment Plan ◽  
Dose Calculation ◽  
Pencil Beam ◽  
Dose Verification ◽  
Beam Scanning ◽  
Water Phantom ◽  
Pencil Beam Scanning ◽  
The Absolute ◽  
Clinical Cases

Purpose: To commission MCsquare (a multi-cores CPU-based dose calculation engine) for pencil beam scanning (PBS) proton therapy, integrate it into RayStation treatment plan system (TPS) to create a dedicated platform for fast independent dose verification. Method: A MCsquare-based independent dose verification platform (MC2InRS) was developed to realize automatic dose re-calculation for clinical use, including data preparation, dose calculation, 2D/3D gamma analysis. MCsquare was commissioned based on in-air lateral dose profiles, integrated depth dose, and the absolute dose of different beam energies for Proteus®ONE. MC2InRS was validated with measurement data using various targets and depths in a water phantom. This study also investigated 15 clinical cases to demonstrate the feasibility and effectiveness of MC2InRS platform in clinic practice. Results: Between simulation and measurement, the distal range differences at 80% (R80) and 20% (R20) dose levels for each energy were below 0.05 mm, and 0.1 mm, respectively, and the absolute dose differences were below 0.5%. 29 out of 36 QA planes reached a 100% gamma passing rate (GPR) for 2%/2mm criteria, and a minimum of 98.3% gamma was obtained in water phantom between simulation and measurement. For the 15 clinical cases investigated, the average 2D GPR (2%/2mm) was 95.4%, 99.3% for MCsquare vs. measurement, MCsquare vs. TPS, respectively. The average 3D GPR (2%/2mm) was 98.9%, 95.3% for MCsquare vs. TPS in water, and computed tomography (CT), respectively. Conclusion: MC2InRS, a fast, independent dose verification platform, has been developed to perform dose verification with high accuracy and efficiency for Pencil Bream Scanning (PBS). Its potential to be applied in routine clinical practice has also been discussed.

Evaluation of BrachyDose Monte Carlo code for HDR brachytherapy: dose comparison against Acuros®BV and TG-43 algorithms

2019 ◽  
Vol 19 (1) ◽  
pp. 76-83
Author(s):  
Ayse Dagli ◽  
Fatma Yurt ◽  
Gultekin Yegin
Keyword(s):  
Cervical Cancer ◽  
Monte Carlo ◽  
Heterogeneous Media ◽  
Dose Calculation ◽  
Extreme Case ◽  
Low Density ◽  
Hdr Brachytherapy ◽  
Dose Calculations ◽  
Dose Distributions ◽  
Water Phantom

AbstractAim:The aim of this study is to investigate the accuracy of dose distributions calculated by the BrachyDose Monte Carlo (MC) code in heterogeneous media for high-dose-rate (HDR) brachytherapy and to evaluate its usability in the clinical brachytherapy treatment planning systems.Materials and methods:For dose comparisons, three different dose calculation algorithms were used in this study. Namely, BrachyDose MC code, Eclipse TG-43 dose calculation tool and Acuros®BV model-based dose calculation algorithm (MBDCA). Dose distributions were obtained using any of the above codes in various scenarios including ‘homogenous water medium scenario’, an ‘extreme case heterogeneous media scenario’ and clinically important ‘a patient with a cervical cancer scenario’. In the ‘extreme case, heterogeneous media scenario’, geometry is a rare combination of unusual high-density and low-density materials and it is chosen to provide a test environment for the propagation of photons in the interface of two materials with different absorption and scattering properties. GammaMed 192Ir Model 12i Source is used as the HDR brachytherapy source in this study. Dose calculations were performed for the cases where there is either a single source or five sources planted into the phantom geometry in all homogenous water phantom and extreme case heterogeneous media scenarios. For the scenario a patient with a cervical cancer, dose calculations were performed in a voxelized rectilinear phantom, which is constructed from a series of computed tomography (CT) slices of a patient, which are obtained from a CT device.Results:In homogeneous water phantom scenario, we observed no statistically significant dose differences among the dose distributions calculated by any of the three algorithms at almost every point in the geometry. In the extreme case heterogeneous media scenario, the dose calculation engines Acuros®BV and BrachyDose are agreed well within statistics in every region of the geometry and even in the points close to the interfaces of low-density and high-density materials. On the other hand, the dose values calculated by these two codes are significantly different from those calculated by the TG-43 algorithm. In the ‘a patient with a cervical cancer scenario’, the calculated D2cc dose difference between Acuros®BV and BrachyDose codes is within 2% in the rectum and 11% for the bladder and sigmoid. There was no meaningful difference in the mean dose values between MBDCAs in the bone structures.Conclusions:In this study, the accurate dose calculation capabilities of the BrachyDose program in HDR brachytherapy were investigated on various scenarios and, as a MC dose calculation tool, its effectiveness in HDR brachytherapy was demonstrated by comparative dose analysis.

scholarly journals MLC parameters from static fields to VMAT plans: an evaluation in a RT-dedicated MC environment (PRIMO)

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Lucia Paganini ◽  
Giacomo Reggiori ◽  
Antonella Stravato ◽  
Valentina Palumbo ◽  
Pietro Mancosu ◽  
...  
Keyword(s):  
Dose Calculation ◽  
Planning System ◽  
Treatment Planning System ◽  
Output Factor ◽  
Water Phantom ◽  
Graphical Environment ◽  
Clinical Complexity ◽  
Output Factors ◽  
Dosimetric Leaf Gap ◽  
Clinical Cases

Abstract Background PRIMO is a graphical environment based on PENELOPE Monte Carlo (MC) simulation of radiotherapy beams able to compute dose distribution in patients, from plans with different techniques. The dosimetric characteristics of an HD-120 MLC (Varian), simulated using PRIMO, were here compared with measurements, and also with Acuros calculations (in the Eclipse treatment planning system, Varian). Materials and methods A 10 MV FFF beam from a Varian EDGE linac equipped with the HD-120 MLC was used for this work. Initially, the linac head was simulated inside PRIMO, and validated against measurements in a water phantom. Then, a series of different MLC patterns were established to assess the MLC dosimetric characteristics. Those tests included: i) static fields: output factors from MLC shaped fields (2 × 2 to 10 × 10 cm2), alternate open and closed leaf pattern, MLC transmitted dose; ii) dynamic fields: dosimetric leaf gap (DLG) evaluated with sweeping gaps, tongue and groove (TG) effect assessed with profiles across alternate open and closed leaves moving across the field. The doses in the different tests were simulated in PRIMO and then compared with EBT3 film measurements in solid water phantom, as well as with Acuros calculations. Finally, MC in PRIMO and Acuros were compared in some clinical cases, summarizing the clinical complexity in view of a possible use of PRIMO as an independent dose calculation check. Results Static output factor MLC tests showed an agreement between MC calculated and measured OF of 0.5%. The dynamic tests presented DLG values of 0.033 ± 0.003 cm and 0.032 ± 0.006 cm for MC and measurements, respectively. Regarding the TG tests, a general agreement between the dose distributions of 1–2% was achieved, except for the extreme patterns (very small gaps/field sizes and high TG effect) were the agreement was about 4–5%. The analysis of the clinical cases, the Gamma agreement between MC in PRIMO and Acuros dose calculation in Eclipse was of 99.5 ± 0.2% for 3%/2 mm criteria of dose difference/distance to agreement. Conclusions MC simulations in the PRIMO environment were in agreement with measurements for the HD-120 MLC in a 10 MV FFF beam from a Varian EDGE linac. This result allowed to consistently compare clinical cases, showing the possible use of PRIMO as an independent dose calculation check tool.

scholarly journals Dose profile evaluation of a 137Cs source using a solid water phantom

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Caio Fernando Teixeira Portela ◽  
Thêssa Cristina Alonso ◽  
Arnado Prata Mourão
Keyword(s):  
Visible Light ◽  
Beam Energy ◽  
Maximum Dose ◽  
Absorbed Dose ◽  
Radiochromic Film ◽  
Radiochromic Films ◽  
Water Phantom ◽  
Dose Profile ◽  
Cesium 137 ◽  
Solid Water

The precision in the dose values delivered in irradiation processes is essential for the efficiency and quality control of these processes. Radiochromic films can be used to record doses and the calibration of these films must be performed so that they can be used as dosimeters. The planning and control of the radiation released in a process allows to adjust the desired dose in the irradiated object. The photons in the primary beam interact with the matter of the object and the beam energy is attenuated due to these interactions. The attenuation depends on the characteristics of the beam and the composition of the irradiated matter. When a beam of photons propagates on an object, it tends to deposit more energy close to the surface and after reaching the maximum dose value, it decreases the dose values with depth. The films used in this work are of the Gafchromic External Beam Therapy (EBT) type, insensitive to visible light and can be prepared in places where sunlight and artificial light exists. Like many other dosimeters, which follow certain protocols, radiochromic films can provide an absolute dose measurement. Radiochromic films are characterized by their linearity, reproducibility, uniformity, sensitivity, and stability after irradiation. For the realization of the experiments, a part of the film to be irradiated was removed designated as background (BG). BG represents a piece of radiochromic film that will not change and reflects changes in film absorption in relation to environmental conditions such as temperature, visible light and scanning light, for example and that must be handled from it way that the film radiated. In this work, irradiations of a solid water phantom were performed using a source of cesium-137 with the deposition of a maximum absorbed dose value of 2.0 Gy. The phantom was placed 1,0 m far from the source collimator. Radiochromic films were placed inside the phantom to obtain the depth variation dose profile and axial dose profiles measured at 1.0 cm depth in the phantom. The dose variation profile in depth allowed to verify that the maximum dose value happened at a depth between 10 and 13 mm, very close to the surface due to the beam energy range (keV). The axial profiles presented a flatness of about 9.4 cm with a total field of 12 cm in diameter. 

Development of solid water phantom using wax

2018 ◽  
Author(s):  
Tomoe Hagio ◽  
Qin Li ◽  
Bahaa Ghammraoui ◽  
Robert J. Jennings ◽  
Benjamin P. Berman ◽  
...  
Keyword(s):  
Water Phantom ◽  
Solid Water

Neutron dosimetry in solid water phantom

2014 ◽  
Author(s):  
Jorge Luis Benites-Rengifo ◽  
Hector Rene Vega-Carrillo
Keyword(s):  
Neutron Dosimetry ◽  
Water Phantom ◽  
Solid Water

scholarly journals A Novel Simple Phantom for Verifying the Dose of Radiation Therapy

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
J. H. Lee ◽  
L. T. Chang ◽  
A. C. Shiau ◽  
C. W. Chen ◽  
Y. J. Liao ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Correction Factor ◽  
Scatter Correction ◽  
Absorbed Dose ◽  
Clinical Tests ◽  
Thermoluminescent Dosimeters ◽  
Water Phantom ◽  
Audit System ◽  
Solid Water ◽  
The Difference

A standard protocol of dosimetric measurements is used by the organizations responsible for verifying that the doses delivered in radiation-therapy institutions are within authorized limits. This study evaluated a self-designed simple auditing phantom for use in verifying the dose of radiation therapy; the phantom design, dose audit system, and clinical tests are described. Thermoluminescent dosimeters (TLDs) were used as postal dosimeters, and mailable phantoms were produced for use in postal audits. Correction factors are important for converting TLD readout values from phantoms into the absorbed dose in water. The phantom scatter correction factor was used to quantify the difference in the scattered dose between a solid water phantom and homemade phantoms; its value ranged from 1.084 to 1.031. The energy-dependence correction factor was used to compare the TLD readout of the unit dose irradiated by audit beam energies with60Co in the solid water phantom; its value was 0.99 to 1.01. The setup-condition factor was used to correct for differences in dose-output calibration conditions. Clinical tests of the device calibrating the dose output revealed that the dose deviation was within 3%. Therefore, our homemade phantoms and dosimetric system can be applied for accurately verifying the doses applied in radiation-therapy institutions.

Thermoluminescent dosimetry for 1 0 3 Pd seeds (model 200) in solid water phantom

1991 ◽  
Vol 18 (3) ◽  
pp. 449-452 ◽  
Author(s):  
Sou-Tung Chiu-Tsao ◽  
Lowell L. Anderson
Keyword(s):  
Thermoluminescent Dosimetry ◽  
Water Phantom ◽  
Solid Water
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