Comparison of calculation algorithms to predict the IQM detector response for various modulation degree of VMAT treatment plans on linear accelerator equipped with the HD120 MLC

2021 ◽  
Author(s):  
Przemysław T. Janiak ◽  
Paweł F. Kukołowicz
Keyword(s):  
Linear Accelerator ◽  
Detector Response ◽  
Calculation Algorithms ◽  
Treatment Plans ◽  
Modulation Degree

scholarly journals Comparison of treatment plans calculated by Ray Tracing and Monte Carlo algorithms for head and thorax radiotherapy with Cyberknife

2017 ◽  
Vol 3 (2) ◽  
pp. 647-650 ◽  
Author(s):  
Kirsten Galonske ◽  
Martin Thiele ◽  
Iris Ernst ◽  
Ralph Lehrke ◽  
Waldemar Zylka
Keyword(s):  
Monte Carlo ◽  
Ray Tracing ◽  
Stereotactic Radiotherapy ◽  
Calculation Algorithm ◽  
Monte Carlo Algorithms ◽  
Body Regions ◽  
Calculation Algorithms ◽  
Treatment Plans ◽  
Homogeneous Regions ◽  
Tumor Types

AbstractThis study investigates differences between treatment plans generated by Ray Tracing (RT) and Monte Carlo (MC) calculation algorithms in homogeneous and heterogeneous body regions. Particularly, we focus on the head and on the thorax, respectively, for robotic stereotactic radiotherapy and radiosurgery with Cyberknife. Radiation plans for tumors located in the head and in the thorax region have been calculated and compared to each other in 47 cases and several tumor types.Assuming MC as the algorithm of highest accuracy it is shown that based on selected dose parameters, RT slightly underestimates the dose in homogeneous regions and overestimates in heterogeneous regions. In addition, deviations occur due to tumor size rendering large differences for small tumors. We conclude that dose prescriptions for radiotherapy treatments should differentiate between RT and MC calculation algorithm. This is especially important for small tumors in heterogeneous body regions.

Dosimetric Comparison of CyberKnife with Other Radiosurgical Modalities for an Ellipsoidal Target

Neurosurgery ◽  
2003 ◽  
Vol 53 (5) ◽  
pp. 1155-1163 ◽  
Author(s):  
Cheng Yu ◽  
Gabor Jozsef ◽  
Michael L.J. Apuzzo ◽  
Zbigniew Petrovich
Keyword(s):  
Radiation Dose ◽  
Linear Accelerator ◽  
Normal Tissue ◽  
Intensity Modulated Radiotherapy ◽  
Treatment Modalities ◽  
Conformity Index ◽  
Target Coverage ◽  
Homogeneity Index ◽  
Three Dimensional Model ◽  
Treatment Plans

Abstract OBJECTIVE To compare treatment plans obtained with the CyberKnife (CK) (Accuray, Inc., Sunnyvale, CA) with those of other commonly used radiosurgical modalities, such as the gamma knife (GK), linear accelerator multiple arcs, conformally shaped static fields, and intensity-modulated radiotherapy (IMRT). METHODS An ellipsoidal simulated target was chosen centrally located in a three-dimensional model of a patient's head acquired with magnetic resonance or computed tomographic imaging. It was 25 mm in diameter and 35 mm long. The aims of treatment plans were 100% target volume coverage with an appropriate isodose line, minimum radiation dose to normal tissue, and clinically acceptable delivery. These plans were evaluated by use of a dose-volume histogram and other commonly used radiosurgical parameters such as target coverage, homogeneity index, and conformity index. RESULTS All selected treatment modalities were equivalent in providing full target coverage. For dose homogeneity, all modalities except for multiple isocenter plans for GK (homogeneity index, 2.0) were similar (homogeneity index, ≅1.25). Dose conformity was essentially equivalent for all treatment plans except for IMRT, which had a slightly higher value (conformity index, ≅1.27). There was a substantial variation in the radiation dose to normal tissue between the studied modalities, particularly at the lower dose levels. CONCLUSION CK plans seemed to be more flexible for a given target size and shape. For a target of limited volume and essentially of any shape, one could obtain similarly good conformal dosimetry with CK and GK. For a regular-shaped but other than spherical target, homogeneous dose distribution could be obtained with all selected modalities except for multiple isocenters, linear accelerator multiple arcs, or GK. Both IMRT and conformally shaped static fields offered good alternative treatment modalities to CK, GK, or linear accelerator multiple arc radiosurgery, with slightly inferior dosimetry in conformity (IMRT).

Comparison of Gamma Analyses with using Different Dosimetric Systems for Pre-Treatment Verification of Intensity Modulated Radiation Therapy

2020 ◽  
Author(s):  
Gokcen Inan ◽  
Osman Vefa Gul
Keyword(s):  
Quality Control ◽  
Radiation Therapy ◽  
Linear Accelerator ◽  
Intensity Modulated Radiation Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Array Detector ◽  
Intensity Modulated ◽  
Treatment Plans ◽  
2D Array

Purpose: The evaluation of the agreement between calculated and measured dose plays an essential role in the quality assurance (QA) procedures of intensity-modulated radiation therapy (IMRT). This study aimed to compare gamma analysis using Portal Dosimetry (PD), Epiqa, and 2D array detector for dose verification of radiotherapy treatment plans. Materials and Methods: Five fields step-and-shoot IMRT plan was used to performed for 20 prostate IMRT patients using the dual-energy DHX linear accelerator (Varian Medical System, Palo Alto, CA, USA). The treatment plans were created using Varian DHX Eclipse treatment planning system (TPS) version 15.1. All measurements were performed by aS500 EPID integrated into Varian DHX linear accelerator and 2D array detector. The dose distribution was evaluated with gamma area histograms (GAHs) generated using different γ criteria (1%/1 mm, 2%/2 mm 3%/2 mm and 3%/3 mm) for dose agreement and distance to agreement parameters. Statistical analyses were evaluated by using Mann Whitney Test and Kruskal-Wallis Test, and p-value of p <0.01 was considered to be significant. Results: The average pass rate for 20 IMRT plans was above 95% for all devices with 2%/2 mm, 3%/2 mm and 3%/3 mm. The mean and standard deviation passing rates (γ ≤1) were found to be 99.80±0.19, 99.35±0.34 and 97.53±0.71 for PD, Epiqa and 2D array respectively. All IMRT plans passed 2%/2 mm, 3%/2 mm and 3%/3 mm gamma by more than 95% of three dosimetric systems. They are all in good agreement with the literature. Conclusion: All three devices are acceptable for quality control of IMRT. Due to the simplicity and fast evaluation process, PD can be preferred for quality control.

scholarly journals Assessment the Photo-neutron Contamination of IMRT and 3D-Conformal Techniques Using Thermo-luminescent Dosimeter (TLD)

2019 ◽  
pp. 1-10
Author(s):  
Ebtesam M. Mohamedy ◽  
Hassan Fathy ◽  
Wafaa M. Khalil ◽  
Nadia L. Helal ◽  
Ehab M. Attalla
Keyword(s):  
Prostate Cancer ◽  
Neutron Monitor ◽  
Linear Accelerator ◽  
Ionization Chamber ◽  
High Energy ◽  
Neutron Production ◽  
Field Size ◽  
Planning System ◽  
Energy Beam ◽  
Treatment Plans

The aim of the study is to evaluate the dependence of photo-neutron production on field size, depth in phantom and distance from isocenter and also to calculate the equivalent neutron doses for PTV and OARs of IMRT and 3DCRT techniques using TLD (600/700).The Linac Siemens Oncor installed at Nasser Institute, Cairo, Egypt. TLDs, Neutron Monitor, Ionization chamber were provided by NIS, the duration of the study was from November 2017 to July 2018. 5 prostate cancer cases were selected treated with high energy beam (15MV) Linear accelerator using 3DCRT and IMRT treatment plans. The OARs were bladder, rectum and femur. Once the plans were completed, there were copied from the planning system onto the RW3 slab phantom in which pairs of TLD chips (600/700) were placed at the exact site of PTV and OARs. The results showed that: The measured photo-neutron decreases from 0.2 mSv/Gy to 0.09 mSv/Gy as increases field sizes from 2x2 cm2 to 20x20 cm2. The measured photo-neutron was maximum at dmax =0.15 mSv/Gy and decreases gradually as increases the depth in phantom reaches to 0.07 mSv/Gy at 10cm depth in phantom. The measured photo-neutron decreases from 1.5 mSv/Gy to 0.02 mSv/Gy when measured at isocenter and at 100cm along the patient couch. Using 3DCRT for PTV and OARs were ranging from 0.027 to 0.39 mSv per photon Gy and for IMRT were 0.135 to 2.34 mSv per photon Gy. In conclusion the photo-neutron production is decreases as increases field size and distance from isocenter along patient couch while increases with depth in phantom up to dmax and decreases gradually as increases depth in phantom. IMRT requires longer beam-on time than 3DCRT leading to worse OARs sparing and increase the production of photo-neutrons than 3DCRT.

Accuracy of two heterogeneity dose calculation algorithms for IMRT in treatment plans designed using an anthropomorphic thorax phantom

2007 ◽  
Vol 34 (5) ◽  
pp. 1850-1857 ◽  
Author(s):  
Scott E. Davidson ◽  
Geoffrey S. Ibbott ◽  
Karl L. Prado ◽  
Lei Dong ◽  
Zhongxing Liao ◽  
...  
Keyword(s):  
Dose Calculation ◽  
Calculation Algorithms ◽  
Dose Calculation Algorithms ◽  
Treatment Plans

Dosimetric comparison of photon beam profile characteristics for different treatment parameters

2017 ◽  
Vol 16 (4) ◽  
pp. 444-450 ◽  
Author(s):  
Qurat-ul-ain Shamsi ◽  
Maria Atiq ◽  
Atia Atiq ◽  
Saeed Ahmad Buzdar ◽  
Khalid Iqbal ◽  
...  
Keyword(s):  
Linear Accelerator ◽  
Radiation Treatment ◽  
Beam Profile ◽  
Photon Beam ◽  
Field Size ◽  
Photon Beams ◽  
Linear Accelerators ◽  
Water Phantom ◽  
Treatment Plans ◽  
Profile Characteristics

AbstractPurposeTo deliver radiation doses with higher accuracy, radiation treatment through megavoltage photon beams from linear accelerators, is accepted widely for treating malignancies. Before calibrating the linear accelerators, it is essential to make a complete analysis of all photon beam profile parameters. The main objective of this exploration was to investigate the 6 and 15 MV photon beam profile characteristics to improve the accuracy of radiation treatment plans.MethodsIn this exploration, treatment parameters like depth, field size and beam energy were varied to observe their effect on dosimetric characteristics of beam profiles in a water phantom, generated by linear accelerator Varian Clinac.ResultsThe results revealed thatDmaxandDmindecreased with increasing depth but increased with increasing field sizes. Both left and right penumbras increased with increasing depth, field size and energy. Homogeneity increased with field size but decreased with depth. Symmetry had no dependence on depth, energy and field size.ConclusionAll the characteristics of photon beam dosimetry were analysed and the characteristics like homogeneity and symmetry measured by an ion chamber in a water phantom came within clinically acceptable level of 3 and 103%, respectively, thus fulfilled the requirements of standard linear accelerator specifications. This exploration can be extended to the determination of beam profile characteristics of electron and photon beams of other energies at various depths and field sizes for designing optimum treatment plans.

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