The aim of this study was to understand the difference between the measured and calculated irradiation attenuations obtained using two algorithms and to identify the influence of couch attenuation on patient dose verification. We performed eight tests of couch attenuation with two photon energies, two longitudinal couch positions, and two rail positions. The couch attenuation was determined using a radiation treatment planning system. The measured and calculated attenuations were compared. We also performed 12 verifications of head-and-neck and rectum cases by using a Delta phantom. The dose deviation (DD), distance to agreement (DTA), and gamma index of pencil-beam convolution (PBC) verifications were nearly the same. The agreement was least consistent for the anisotropic analytical algorithm (AAA) without the couch for the head-and-neck case, in which the DD, DTA, and gamma index were 74.4%, 99.3%, and 89%, respectively; for the rectum case, the corresponding values were 56.2%, 95.1%, and 92.4%. We suggest that dose verification should be performed using the following three metrics simultaneously: DD, DTA, and the gamma index.
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http://dx.doi.org/10.1038/srep43336 | DOI Listing |
Rep Pract Oncol Radiother
December 2024
Department of Biomedical Physics, Faculty of Physics, Adam Mickiewicz University, Poznań, Poland.
Background: The purpose of this study is to determine the effect of the type of I-125 radioactive source on dose distribution in the planning process of ultra-low dose rate (uLDR) prostate brachytherapy.
Material And Methods: 7 patients who had undergone brachytherapy in our center were included in the study. Dose in five geometrical points were analyzed for 12 types of implants that are available on the market.
Phys Med
January 2025
Department of Radiation Oncology, The Third Affiliated Hospital, Sun Yan-Sen University, Guangzhou 510630, China. Electronic address:
A preliminary study was conducted using electronic portal imaging device (EPID) based dose verification in pre-treatment and in vivo dose reconstruction modes for breast cancer intensity-modulated radiation therapy (IMRT) technique with known repositioning set-up errors. For 43 IMRT plans, the set-up errors were determined from 43 sets of EPID images and 258 sets of cone beam computed tomography images. In-house developed Edose software was used to reconstruct the dose distribution using the pre-treatment and on-treatment (in vivo) EPID acquired fluence maps.
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December 2024
Department of Radiation Oncology, The First Affiliated Hospital of Guangzhou Medical University, GuangZhou, GuangDong, China.
Background: This study investigates the impact of convergence mode (CM) in Eclipse (Varian Medical Systems) on the quality and complexity of volumetric modulated arc therapy (VMAT) plans for nasopharyngeal carcinoma (NPC) patients.
Methods: We retrospectively analyzed data from 21 NPC patients. For each patient, three VMAT plans with different CM settings (Off, On, and Extended) were created using identical optimization objectives.
J Appl Clin Med Phys
December 2024
Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, Arizona, USA.
Background: Conventional approaches for emergent or expedited palliative radiotherapy (RT) involve the application of cumbersome vendor-provided solutions and/or multiple patient appointments to complete the RT workflow within a compressed timeframe.
Purpose: This report delineates the clinical development of an in-house, semi-automated Cone-beam computed tomography (CBCT)-based simulation-free platform for expedited palliative RT on conventional linacs, intended to supplant existing techniques employed at this institution.
Methods: The internal software, termed SimFree Wizard (SFW), was engineered utilizing a C#-based application programming interface integrated within the treatment planning system (TPS).
Appl Radiat Isot
December 2024
Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
A gamma cell unit is used for gamma irradiation of small volume samples. Due to the sample volume, there is a dose distribution, which is imperative to be known for appropriate irradiation. In this study, samples of agarose Fricke gel dosimeters were prepared for the dose mapping of the gamma cell unit available in our laboratory.
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