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https://www.readbyqxmd.com/read/28528467/changes-in-deviation-of-absorbed-dose-to-water-among-users-by-chamber-calibration-shift
#1
Tetsurou Katayose, Hidetoshi Saitoh, Mitsunobu Igari, Weishan Chang, Shimpei Hashimoto, Mie Morioka
PURPOSE: The JSMP01 dosimetry protocol had adopted the provisional (60)Co calibration coefficient [Formula: see text], namely, the product of exposure calibration coefficient N C and conversion coefficient k D,X. After that, the absorbed dose to water D w standard was established, and the JSMP12 protocol adopted the [Formula: see text] calibration. In this study, the influence of the calibration shift on the measurement of D w among users was analyzed. MATERIALS AND METHODS: The intercomparison of the D w using an ionization chamber was annually performed by visiting related hospitals...
May 20, 2017: Japanese Journal of Radiology
https://www.readbyqxmd.com/read/28527605/analysis-of-gafchromic-ebt3-film-calibration-irradiated-with-gamma-rays-from-different-systems-gamma-knife-and-cobalt-60-unit
#2
Monsen Najafi, Ghazale Geraily, Alireza Shirazi, Mahbod Esfahani, Javad Teimouri
In recent years, Gafchromic films are used as an advanced instrument for dosimetry systems. The EBT3 films are a new generation of Gafchromic films. Our main interest is to compare the response of the EBT3 films exposed to gamma rays provided by the Theratron 780C as a conventional radiotherapy system and the Leksell Gamma Knife as a stereotactic radiotherapy system (SRS). Both systems use Cobalt-60 sources, thus using the same energy. However, other factors such as source-to-axis distance, number of sources, dose rate, direction of irradiation, shape of phantom, the field shape of radiation, and different scatter contribution may influence the calibration curve...
May 17, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28526893/do-we-need-3d-tube-current-modulation-information-for-accurate-organ-dosimetry-in-chest-ct-protocols-dose-comparisons
#3
Xochitl Lopez-Rendon, Guozhi Zhang, Walter Coudyzer, Wim Develter, Hilde Bosmans, Federica Zanca
OBJECTIVES: To compare the lung and breast dose associated with three chest protocols: standard, organ-based tube current modulation (OBTCM) and fast-speed scanning; and to estimate the error associated with organ dose when modelling the longitudinal (z-) TCM versus the 3D-TCM in Monte Carlo simulations (MC) for these three protocols. METHOD: Five adult and three paediatric cadavers with different BMI were scanned. The CTDIvol of the OBTCM and the fast-speed protocols were matched to the patient-specific CTDIvol of the standard protocol...
May 19, 2017: European Radiology
https://www.readbyqxmd.com/read/28525908/mri-based-radiotherapy-planning-method-using-rigid-image-registration-technique-combined-with-outer-body-correction-scheme-a%C3%A2-feasibility-study
#4
Ki Mun Kang, Hoon Sik Choi, Bae Kwon Jeong, Jin Ho Song, In-Bong Ha, Yun Hee Lee, Chul Hang Kim, Hojin Jeong
An alternative pseudo CT generation method for magnetic resonance image (MRI)-based radiotherapy planning was investigated in the work. A pseudo CT was initially generated using the rigid image registration between the planning MRI and previously acquired diagnostic CT scan. The pseudo CT generated was then refined to have the same morphology with that of the referenced planning image scan by applying the outer body correction scheme. This method was applied to some sample of brain image data and the feasibility of the method was assessed by comparing dosimetry results with those from the current gold standard CT-based calculations...
May 7, 2017: Oncotarget
https://www.readbyqxmd.com/read/28524743/nanoparticle-exposures-from-nano-enabled-toner-based-printing-equipment-and-human-health-state-of-science-and-future-research-needs
#5
Sandra Vanessa Pirela, John Martin, Dhimiter Bello, Philip Demokritou
Toner formulations used by laser printers (LP) and photocopiers (PC), collectively called "toner-based printing equipment" (TPE), are nano-enabled products (NEP) because they contain several engineered nanomaterials (ENM) that improve toner performance. It has been shown that during consumer use (printing), these ENM are released in the air, together with other semi-volatile organic nanoparticles, and newly formed gaseous co-pollutants such as volatile organic compounds (VOC). The aim of this review is to detail and analyze physico-chemical and morphological (PCM), as well as the toxicological properties of particulate matter (PM) emissions from TPE...
May 19, 2017: Critical Reviews in Toxicology
https://www.readbyqxmd.com/read/28523582/first-in-human-radiation-dosimetry-of-68-ga-nodaga-rgdyk
#6
Silvano Gnesin, Periklis Mitsakis, Francesco Cicone, Emmanuel Deshayes, Vincent Dunet, Augusto F Gallino, Marek Kosinski, Sébastien Baechler, Franz Buchegger, David Viertl, John O Prior
BACKGROUND: Integrin-targeting radiopharmaceuticals have potential broad applications, spanning from cancer theranostics to cardiovascular diseases. We have previously reported preclinical dosimetry results of (68)Ga-NODAGA-RGDyK in mice. This study presents the first human dosimetry of (68)Ga-NODAGA-RGDyK in the five consecutive patients included in a clinical imaging protocol of carotid atherosclerotic plaques. Five male patients underwent whole-body time-of-flight (TOF) PET/CT scans 10, 60 and 120 min after tracer injection (200 MBq)...
December 2017: EJNMMI Research
https://www.readbyqxmd.com/read/28522118/a-national-survey-of-hdr-source-knowledge-among-practicing-radiation-oncologists-and-residents-establishing-a-willingness-to-pay-threshold-for-cobalt-60-usage
#7
Raymond Mailhot Vega, Wesley Talcott, Omar Ishaq, Patrice Cohen, Christina J Small, Tamara Duckworth, Gustavo Sarria Bardales, Carmen A Perez, Peter B Schiff, William Small, Matthew M Harkenrider
PURPOSE: Ir-192 is the predominant source for high-dose-rate (HDR) brachytherapy in United States markets. Co-60, with longer half-life and fewer source exchanges, has piloted abroad with comparable clinical dosimetry but increased shielding requirements. We sought to identify practitioner knowledge of Co-60 and establish acceptable willingness-to-pay (WTP) thresholds for additional shielding requirements for use in future cost-benefit analysis. METHODS AND MATERIALS: A nationwide survey of U...
May 15, 2017: Brachytherapy
https://www.readbyqxmd.com/read/28521403/comparative-study-on-dosimetry-of-vmat-and-imrt-in-assisted-radiotherapy-after-radical-resection-of-rectal-cancer
#8
Jianguo Shi, Fujun Yang, Xiangbai Ju, Yudong Huang, Fenge Jiang
The present study compared the dosimetric differences of volumetric modulated arc therapy (VMAT) and 7-field intensity modulated radiation therapy technology (7F-IMRT) in assisted radiotherapy plan after resection of rectal carcinoma. Ten cases of patients at stages II-III of rectal cancer transabdominal resection with postoperative pelvic radiotherapy underwent 7F-IMRT and VMAT radiotherapy plan design using the CMS Monaco treatment planning system. We compared the dose distribution, the number of organs at risk and the number of machines in the two groups...
May 2017: Oncology Letters
https://www.readbyqxmd.com/read/28516398/gynecological-brachytherapy-for-postoperative-endometrial-cancer-dosimetric-analysis-ir-192-vs-co-60
#9
V Tormo Ferrero, R Duque Ugarte, M Á Berenguer Francés, R Cardenal Maciá
INTRODUCTION: Endovaginal brachytherapy treatment dosimetry differences were studied using Ir-192 or Co-60 sources for postoperative endometrial cancer. MATERIALS AND METHODS: A prospective descriptive study was conducted. Thirty-six dosimetry plans of different patients were studied (15 by Ir-192 and 21 by Co-60). Variables studied included D2cc Rectum, D2cc Bladder, D2cc Sigmoid, dose percentage at point 0 (applicator surface on the top of the cylinder) and dose percentage at point 1 (5 mm deep on the top of the cylinder)...
May 17, 2017: Clinical & Translational Oncology
https://www.readbyqxmd.com/read/28513854/verification-of-dose-profiles-generated-by-the-convolution-algorithm-of-the-gamma-knife-%C3%A2-radiosurgery-planning-system
#10
Hyun-Tai Chung, Jeong-Hoon Park, Kook Jin Chun
PURPOSE: A convolution algorithm that takes into account electron-density inhomogeneity was recently introduced to calculate dose distributions for the Gamma Knife (GK) Perfexion(™) treatment planning program. The accuracies of the dose distributions computed using the convolution method were assessed using an anthropomorphic phantom and film dosimetry. METHODS: Absorbed-dose distributions inside a phantom (CIRS Radiosurgery Head Phantom, Model 605) were calculated using the convolution method of the GK treatment-planning software (Leksell Gamma Plan(®) version 10...
May 17, 2017: Medical Physics
https://www.readbyqxmd.com/read/28511893/assessment-of-the-effectiveness-of-attenuation-of-pb-aprons-by-using-tld-dosimetry-and-monte-carlo-calculations
#11
H Olaya Dávila, J A Díaz Merchán, H R Vega Carrillo, S A Martínez Ovalle
We developed an experimental set-up by using a continuous emission X-ray (Pantak DXT-3000) and three types of Pb aprons, with thicknesses of 0.25, 0.5, and 0.75mm, coated with Mylar fiber on their surface. Aprons were placed at a distance of 2.5m from the focus. Aluminum filtration was performed at the beam output to reproduce the qualities of narrow beams, N40 (Eeffective =33keV), N80 (Eeffective =65keV), and N100 (Eeffective =83keV), according to the ISO standard 4037 (1-3). Each apron was fixed with 10 thermoluminescent dosimeters (TLDs) over its surface, five dosimeters before and five dosimeters after irradiation with X-rays...
May 10, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28510733/radon-dosimetry-for-workers-icrp-s-approach
#12
James W Marsh, Dominique Laurier, Margot Tirmarche
The International Commission on Radiological Protection (ICRP) has recently published two reports on radon exposure; Publication 115 on lung cancer risks from radon and radon progeny and Publication 126 on radiological protection against radon exposure. A specific graded approach for the control of radon in workplaces is recommended where a dose assessment is required in certain situations. In its forthcoming publication on Occupational Intakes of Radionuclides (OIR) document, Part 3, effective dose coefficients for radon and thoron will be provided...
May 16, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28509566/respiratory-motion-during-90-yttrium-pet-contributes-to-underestimation-of-tumor-dose-and-overestimation-of-normal-liver-tissue-dose
#13
Line Ausland, Mona-Elisabeth Revheim, Arne Skretting, Caroline Stokke
Background Yttrium-90 dosimetry after radioembolization is reliant on accurate quantitative imaging of the microsphere deposition. Previous studies have focused on the correction of geometrical resolution effects. Purpose To uncover additional effects of respiratory motion. Material and Methods Mathematical models describing spherical tumors were formed and two blurring effects, limited geometrical resolution and respiratory motion, were simulated. The virtual images were used as basis for dose volume histogram estimations by convolving the radioactivity representations with a dose point kernel...
January 1, 2017: Acta Radiologica
https://www.readbyqxmd.com/read/28507988/comparative-therapeutic-efficacy-of-153-sm-edtmp-and-177-lu-edtmp-for-bone-pain-palliation-in-patients-with-skeletal-metastases-patients-pain-score-analysis-and-personalized-dosimetry
#14
Sarika Sharma, Baljinder Singh, Ashwani Koul, Bhagwant Rai Mittal
INTRODUCTION: The aim of the present study was to compare the therapeutic efficacy of (153)Sm-EDTMP and (177)Lu-EDTMP in pain palliation in cancer patients with skeletal metastases. MATERIALS AND METHODS: Thirty patients (25 M:5 F, mean age: 66.0 ± 14.7 years) of breast/prostate cancer with documented skeletal metastases were recruited prospectively. Twenty patients were considered randomly for treatment with (153)Sm-EDTMP and with (177)Lu-EDTMP in 10 patients, respectively...
2017: Frontiers in Medicine
https://www.readbyqxmd.com/read/28507457/evaluating-the-performance-of-tg-43-protocol-in-esophageal-hdr-brachytherapy-viewpoint-to-trachea-inhomogeneity
#15
Seyed Mohsen Hosseini Daghigh, Hamid Reza Baghani, Seyed Mahmoud Reza Aghamiri, Seyed Rabi Mahdavi
AIM: The aim of this study is to evaluate the effect of air within trachea on dose calculations of esophageal HDR brachytherapy treatment planning. BACKGROUND: Dose calculations in esophageal HDR brachytherapy treatment planning systems are greatly based on TG-43 protocol which in all materials are considered to be water equivalent. MATERIALS AND METHODS: A cylindrical PMMA phantom with a tube in the center (neck equivalent phantom) accompanied by Flexitron HDR brachytherapy system was used in this study...
July 2017: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/28506453/challenges-of-dosimetry-of-ultra-short-pulsed-very-high-energy-electron-beams
#16
Anna Subiel, Vadim Moskvin, Gregor H Welsh, Silvia Cipiccia, David Reboredo, Colleen DesRosiers, Dino A Jaroszynski
Very high energy electrons (VHEE) in the range from 100 to 250MeV have the potential of becoming an alternative modality in radiotherapy because of their improved dosimetric properties compared with 6-20MV photons generated by clinical linear accelerators (LINACs). VHEE beams have characteristics unlike any other beams currently used for radiotherapy: femtosecond to picosecond duration electron bunches, which leads to very high dose per pulse, and energies that exceed that currently used in clinical applications...
May 11, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28505478/dose-assessment-in-environmental-radiological-protection-state-of-the-art-and-perspectives
#17
REVIEW
Karolina Stark, José M Goméz-Ros, Jordi Vives I Batlle, Elisabeth Lindbo Hansen, Karine Beaugelin-Seiller, Lawrence A Kapustka, Michael D Wood, Clare Bradshaw, Almudena Real, Corynne McGuire, Thomas G Hinton
Exposure to radiation is a potential hazard to humans and the environment. The Fukushima accident reminded the world of the importance of a reliable risk management system that incorporates the dose received from radiation exposures. The dose to humans from exposure to radiation can be quantified using a well-defined system; its environmental equivalent, however, is still in a developmental state. Additionally, the results of several papers published over the last decade have been criticized because of poor dosimetry...
May 12, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28504642/ion-recombination-correction-factor-in-scanned-light-ion-beams-for-absolute-dose-measurement-using-plane-parallel-ionisation-chambers
#18
Severine Rossomme, Julian Horn, Stephan Brons, Oliver Jaekel, Andrea Mairani, Mario Ciocca, Vincent Floquet, Francesco Romano, Diana Rodriguez Garcia, Stefaan Vynckier, Hugo Palmans
Based on international reference dosimetry protocols for light-ion beams, a correction factor (<i>k<sub>s</sub></i>) has to be applied to the response of a plane-parallel ionisation chamber, to account for recombination of negative and positive charges in its air cavity before these charges can be collected on the electrodes. In this work, <i>k<sub>s</sub></i> for IBA PPC40 Roos-type chambers is investigated in four scanned light-ion beams (proton, helium, carbon and oxygen)...
May 15, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28504546/use-of-a-3d-printed-abdominal-compression-device-to-facilitate-ct-fluoroscopy-guided-percutaneous-interventions
#19
Yan Epelboym, Paul B Shyn, Ahmed Hosny, Tatiana Kelil, Jeffrey Forris Beecham Chick, Nikunj R Chauhan, Beth Ripley, Richard D Nawfel, Francis J Scholz
OBJECTIVE: The purpose of this article is to describe a handheld external compression device used to facilitate CT fluoroscopy-guided percutaneous interventions in the abdomen. CONCLUSION: The device was designed with computer-aided design software to modify an existing gastrointestinal fluoroscopy compression device and was constructed by 3D printing. This abdominal compression device facilitates access to interventional targets, and its use minimizes radiation exposure of radiologists...
May 15, 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/28501429/permanent-prostate-brachytherapy-postimplant-mri-dosimetry-using-positive-contrast-mri-markers
#20
Geoffrey V Martin, Thomas J Pugh, Usama Mahmood, Rajat J Kudchadker, Jihong Wang, Teresa L Bruno, Tharakeswara Bathala, Pierre Blanchard, Steven J Frank
PURPOSE: Permanent prostate brachytherapy dosimetry using computed tomography-magnetic resonance imaging (CT-MRI) fusion combines the anatomic detail of MRI with seed localization on CT but requires multimodality imaging acquisition and fusion. The purpose of this study was to compare the utility of MRI only postimplant dosimetry to standard CT-MRI fusion-based dosimetry. METHODS AND MATERIALS: Twenty-three patients undergoing permanent prostate brachytherapy with use of positive contrast MRI markers were included in this study...
May 10, 2017: Brachytherapy
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