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Radiation dose measurements

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https://www.readbyqxmd.com/read/29785725/density-scaling-of-phantom-materials-for-a-3d-dose-verification-system
#1
Kensuke Tani, Yukio Fujita, Akihisa Wakita, Ryohei Miyasaka, Ryuzo Uehara, Takumi Kodama, Yuya Suzuki, Ako Aikawa, Norifumi Mizuno, Jiro Kawamori, Hidetoshi Saitoh
In this study, the optimum density scaling factors of phantom materials for a commercially available three-dimensional (3D) dose verification system (Delta4) were investigated in order to improve the accuracy of the calculated dose distributions in the phantom materials. At field sizes of 10 × 10 and 5 × 5 cm2 with the same geometry, tissue-phantom ratios (TPRs) in water, polymethyl methacrylate (PMMA), and Plastic Water Diagnostic Therapy (PWDT) were measured, and TPRs in various density scaling factors of water were calculated by Monte Carlo simulation, Adaptive Convolve (AdC, Pinnacle3 ), Collapsed Cone Convolution (CCC, RayStation), and AcurosXB (AXB, Eclipse)...
May 21, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29784460/review-of-real-time-3-dimensional-image-guided-radiation-therapy-on-standard-equipped-cancer-radiation-therapy-systems-are-we-at-the-tipping-point-for-the-era-of-real-time-radiation-therapy
#2
Paul J Keall, Doan Trang Nguyen, Ricky O'Brien, Pengpeng Zhang, Laura Happersett, Jenny Bertholet, Per R Poulsen
PURPOSE: To review real-time 3-dimensional (3D) image guided radiation therapy (IGRT) on standard-equipped cancer radiation therapy systems, focusing on clinically implemented solutions. METHODS AND MATERIALS: Three groups in 3 continents have clinically implemented novel real-time 3D IGRT solutions on standard-equipped linear accelerators. These technologies encompass kilovoltage, combined megavoltage-kilovoltage, and combined kilovoltage-optical imaging. The cancer sites treated span pelvic and abdominal tumors for which respiratory motion is present...
April 14, 2018: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/29780829/the-effect-of-c-arm-mobility-and-field-of-vision-on-radiation-exposure-in-the-treatment-of-proximal-femoral-fractures-a-randomized-clinical-trial
#3
Mahmut Kalem, Kerem Başarır, Hakan Kocaoğlu, Ercan Şahin, Hakan Kınık
Objectives: To examine the effect of fluoroscopy devices with different sizes of image intensifier and C-arm maneuverability on operating time, fluoroscopy time, radiation dose and reduction, and fixation quality at intertrochanteric femoral fractures. Design: Single-center, randomized, prospective study. Setting: Academic Level I trauma hospital. Patients and Intervention: 34 patients treated with cephalomedullary nailing for a stable, intertrochanteric proximal femur fracture (OTA A1)...
2018: BioMed Research International
https://www.readbyqxmd.com/read/29780047/-evaluation-of-a-2d-diode-array-corresponding-to-flattening-filter-free-x-ray-beams
#4
Tomoko Kimura, Jun-Ichi Fukunaga, Taka-Aki Hirose, Ryota Hirayama
Recently, a medical linear accelerator with a flattening filter free (FFF) mode has led to the use of FFF X-ray beams at clinical sites. The usefulness of FFF X-ray beams in high-precision radiation therapy has been reported. Therefore, the quality assurance and quality control for FFF X-ray beams have become necessary. In this study, the characteristics of the detectors of a newly developed 2-D diode array (MapCHECK2, Sun Nuclear Corporation) for FFF X-ray beams, i.e., dose reproducibility, dose rate dependence, dose linearity, and output factor, were evaluated...
2018: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/29779953/a-quality-assurance-device-for-measuring-afterloader-performance-and-transit-dose-for-nasobiliary-high-dose-rate-brachytherapy
#5
Christopher L Deufel, John P Mullins, Mark J Zakhary
PURPOSE: Nasobiliary high-dose-rate (HDR) brachytherapy has emerged as an effective tool to boost the radiation dose for patients with unresectable perihilar cholangiocarcinoma. This work describes a quality assurance (QA) tool for measuring the HDR afterloader's performance, including the transit dose, when the source wire travels through a tortuous nasobiliary catheter path. METHODS AND MATERIALS: The nasobiliary QA device was designed to mimic the anatomical path of a nasobiliary catheter, including the nasal, stomach, duodenum, and bile duct loops...
May 17, 2018: Brachytherapy
https://www.readbyqxmd.com/read/29778781/fullerenol-c-60-oh-36-protects-human-erythrocyte-membrane-against-high-energy-electrons
#6
Jacek Grebowski, Paulina Kazmierska, Grzegorz Litwinienko, Anna Lankoff, Marian Wolszczak, Anita Krokosz
Fullerenols (polyhydroxylated fullerene C60 ) are nanomaterial with potentially broad applicability in biomedical sciences with high antioxidant ability, thus, we investigated the radioprotecting potential of fullerenol C60 (OH)36 on human erythrocytes irradiated by high-energy electrons of 6 MeV. The results demonstrate that C60 (OH)36 at concentration of 150 μg/mL protects the erythrocytes against the radiation-induced hemolysis (comparing to non-protected cells, we observed 30% and 39% protection for 0...
May 17, 2018: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29777432/qualitative-study-of-mechanical-parameters-of-conventional-diagnostic-x-ray-machines-in-mizoram
#7
Jonathan Lalrinmawia, Kham Suan Pau, Ramesh Chandra Tiwari
The present study examined the mechanical attributes of 135 conventional diagnostic X-ray machines in Mizoram, India. The purpose of studying the X-ray mechanical parameters, such as congruency, perpendicularity of the central beam, and half-value layer, was to improve the quality of the diagnostic image and reduce the patient dose. A battery-operated portable dosimeter was used to measure output radiation of the X-ray machine. The half-value layer was measured at a constant accelerating potential of 70 kVp and tube load...
May 18, 2018: Radiological Physics and Technology
https://www.readbyqxmd.com/read/29775404/evaluation-of-chromosomal-aberrations-induced-by-188-re-dendrimer-nanosystem-on-b16f1-melanoma-cells
#8
Marcos Tassano, Natalia Oddone, Marcelo Fernández, Williams Porcal, María Fernanda García, Wilner Martínez, Juan Claudio Benech, Pablo Cabral
PURPOSE: Study of rhenium-188 labeling of polyamidoamine (PAMAM) generation 4 (G4) dendrimer and its evaluation on biodistribution and chromosomal aberrations in melanoma cells induced by ionizing radiation as potential treatment agent. MATERIALS AND METHODS: Dendrimers were first conjugated with Suc-HYNIC (Succinimidyl 6-hydrazinopyridine-3-carboxylic acid hydrochloride). Dendrimer-HYNIC was then incubated with 188 ReO4 - . Biodistribution were performed administrating 188 Re-dendrimer to normal (NM) or melanoma-bearing mice (MBM)...
May 18, 2018: International Journal of Radiation Biology
https://www.readbyqxmd.com/read/29772057/a-4d-global-respiratory-motion-model-of-the-thorax-based-on-ct-images-a-proof-of-concept
#9
H Fayad, M Gilles, T Pan, D Visvikis
PURPOSE: Respiratory motion reduces the sensitivity and specificity of medical images especially in the thoracic and abdominal areas. It may affect applications such as cancer diagnostic imaging and/or radiation therapy (RT). Solutions to this issue include modelling of the respiratory motion in order to optimize both diagnostic and therapeutic protocols. Personalised motion modeling required patient specific four dimensional (4D) imaging which in the case of 4D computed tomography (4D CT) acquisition is associated with an increased dose...
May 17, 2018: Medical Physics
https://www.readbyqxmd.com/read/29769516/staying-safe-from-radiation-exposure-in-cath-lab-a-review
#10
K Pasha, H R Khan, A A Sumon
A successful cardiac catheterization Laboratory radiation safety program must manage patient and staff safety by reducing exposure to ionizing radiation to a level that is as low as reasonably achievable (ALARA). The first step in radiation safety is to avoid unnecessary use of ionizing radiation by justification of exposure, one of the basic principles of radiation protection. All individuals involved in fluoroscopic imaging procedures should familiarize themselves to the measures to protect themselves from exposure to unsafe doses of ionizing radiation...
April 2018: Mymensingh Medical Journal: MMJ
https://www.readbyqxmd.com/read/29764458/cone-beam-computed-tomography-in-implant-dentistry-recommendations-for-clinical-use
#11
Reinhilde Jacobs, Benjamin Salmon, Marina Codari, Bassam Hassan, Michael M Bornstein
BACKGROUND: In implant dentistry, three-dimensional (3D) imaging can be realised by dental cone beam computed tomography (CBCT), offering volumetric data on jaw bones and teeth with relatively low radiation doses and costs. The latter may explain why the market has been steadily growing since the first dental CBCT system appeared two decades ago. More than 85 different CBCT devices are currently available and this exponential growth has created a gap between scientific evidence and existing CBCT machines...
May 15, 2018: BMC Oral Health
https://www.readbyqxmd.com/read/29763446/detector-specific-correction-factors-in-radiosurgery-beams-and-their-impact-on-dose-distribution-calculations
#12
Olivia A García-Garduño, Manuel A Rodríguez-Ávila, José M Lárraga-Gutiérrez
Silicon-diode-based detectors are commonly used for the dosimetry of small radiotherapy beams due to their relatively small volumes and high sensitivity to ionizing radiation. Nevertheless, silicon-diode-based detectors tend to over-respond in small fields because of their high density relative to water. For that reason, detector-specific beam correction factors ([Formula: see text]) have been recommended not only to correct the total scatter factors but also to correct the tissue maximum and off-axis ratios...
2018: PloS One
https://www.readbyqxmd.com/read/29762341/radiation-exposure-to-the-surgeons-and-patients-in-fluoroscopic-guided-segmental-pedicle-screw-placement-for-pediatric-scoliosis
#13
Hiroyuki Yoshihara, Carl B Paulino
STUDY DESIGN: Prospective case series OBJECTIVE.: To analyze the radiation exposure to the surgeons and patients in fluoroscopic-guided segmental pedicle screw placement for pediatric scoliosis SUMMARY OF BACKGROUND DATA.: Fluoroscopic-guided pedicle screw placement is a safer technique for pedicle screw placement in spinal deformity. However, radiation exposure is a concern, particularly for spine surgeons due to the requirement of multiple pedicle screws in spinal deformity surgery...
May 14, 2018: Spine
https://www.readbyqxmd.com/read/29762188/the-reliability-of-radiostereometric-analysis-in-determining-physeal-motion-in-slipped-capital-femoral-epiphysis-in-standard-uniplanar-and-low-dose-eos-biplanar-radiography-a-phantom-model-study
#14
Jennifer K Hurry, Saad Rehan, Alan J Spurway, Elise K Laende, Janie L Astephen Wilson, Karl J Logan, Michael J Dunbar, Ron El-Hawary
Physeal closure after slipped capital femoral epiphysis fixation can be difficult to assess on two-dimensional conventional radiographs. Radiostereometric analysis offers improved motion detection over conventional radiography, whereas the EOS biplanar imager provides a means for low radiation weight-bearing images. This phantom study assessed the reliability of measuring motion using radiostereometric analysis in the EOS using a slipped capital femoral epiphysis model. The accuracy and precision were better than 0...
May 14, 2018: Journal of Pediatric Orthopedics. Part B
https://www.readbyqxmd.com/read/29761987/-comparison-of-planning-quality-and-delivery-efficiency-between-volumetric-modulated-arc-therapy-and-dynamic-intensity-modulated-radiation-therapy-for-nasopharyngeal-carcinoma-with-more-than-4-prescribed-dose-levels
#15
Pengfei Jia, Jun Xu, Xiaoxi Zhou, Jian Chen, Lemin Tang
The aim of this study is to compare the planning quality and delivery efficiency between dynamic intensity modulated radiation therapy (d-IMRT) and dual arc volumetric modulated arc therapy (VMAT) systematically for nasopharyngeal carcinoma (NPC) patients with multi-prescribed dose levels, and to analyze the correlations between target volumes and plan qualities. A total of 20 patients of NPC with 4-5 prescribed dose levels to achieve simultaneous integrated boost (SIB) treated by sliding window d-IMRT in our department from 2014 to 2015 were re-planned with dual arc VMAT...
December 1, 2017: Sheng Wu Yi Xue Gong Cheng Xue za Zhi, Journal of Biomedical Engineering, Shengwu Yixue Gongchengxue Zazhi
https://www.readbyqxmd.com/read/29760949/new-patient-controlled-abdominal-compression-method-in-radiography-radiation-dose-and-image-quality
#16
Oili Piippo-Huotari, Eva Norrman, Agneta Anderzén-Carlsson, Håkan Geijer
Background: The radiation dose for patients can be reduced with many methods and one way is to use abdominal compression. In this study, the radiation dose and image quality for a new patient-controlled compression device were compared with conventional compression and compression in the prone position . Purpose: To compare radiation dose and image quality of patient-controlled compression compared with conventional and prone compression in general radiography. Material and Methods: An experimental design with quantitative approach...
May 2018: Acta Radiologica Open
https://www.readbyqxmd.com/read/29759487/clinical-examination-of-proton-pencil-beam-scanning-on-a-moving-anthropomorphic-lung-phantom
#17
Peng Wang, Shikui Tang, Paige A Taylor, David E Cummings, Martin Janson, Erik Traneus, Jared D Sturgeon, Andrew K Lee, Chang Chang
The objective of this study was to examine the use of proton pencil beam scanning for the treatment of moving lung tumors. A single-field uniform dose proton pencil beam scanning (PBS) plan was generated for the standard thorax phantom designed by the Imaging and Radiation Oncology Core (IROC) Houston QA Center. Robust optimization, including range and setup uncertainties as well as volumetric repainting, was used for the plan. Patient-specific quality assurance (QA) measurements were performed using both a water tank and a custom heterogeneous QA phantom...
May 11, 2018: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/29757473/iterative-inversion-of-deformation-vector-fields-with-feedback-control
#18
Abhishek Kumar Dubey, Alexandros-Stavros Iliopoulos, Xiaobai Sun, Fang-Fang Yin, Lei Ren
PURPOSE: Often, the inverse deformation vector field (DVF) is needed together with the corresponding forward DVF in 4D reconstruction and dose calculation, adaptive radiation therapy, and simultaneous deformable registration. This study aims at improving both accuracy and efficiency of iterative algorithms for DVF inversion, and advancing our understanding of divergence and latency conditions. METHOD: We introduce a framework of fixed-point iteration algorithms with active feedback control for DVF inversion...
May 14, 2018: Medical Physics
https://www.readbyqxmd.com/read/29757432/estimation-of-effective-dose-from-external-exposure-due-to-short-lived-nuclides-in-the-prefectures-surrounding-fukushima
#19
Hirokazu Miyatake, Nobuaki Yoshizawa, Gen Suzuki
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in a release of radionuclides into the environment. Since the accident, measurements of radiation in the environment such as air dose rate and deposition density of radionuclides have been performed by various organizations and universities. In particular, Japan Atomic Energy Agency (JAEA) has been performing observations of air dose rate using a car-borne survey system continuously over widespread areas. Based on the data measured by JAEA, we estimated effective dose from external exposure in the prefectures surrounding Fukushima...
May 11, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29757158/origins-of-the-changing-detector-response-in-small-megavoltage-photon-radiation-fields
#20
John D Fenwick, Georgios Georgiou, Carl Graham Rowbottom, Tracy S A Underwood, Sudhir Kumar, Alan E Nahum
Differences in detector response between measured small fields, fclin, and wider reference fields, fmsr, can be overcome by using correction factors or by designing detectors with field-size invariant responses. The changing response in small fields is caused by perturbations of the electron fluence within the detector sensitive volume. For solid-state detectors, it has recently been suggested that these perturbations might be caused by the non-water-equivalent effective atomic numbers Z of detector materials, rather than by their non-water-like densities...
May 14, 2018: Physics in Medicine and Biology
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