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https://www.readbyqxmd.com/read/28428474/evaluation-of-absorbed-dose-for-cbct-in-image-guided-radiation-therapy-comparison-of-each-devices-and-facilities
#1
Yumiko Kitazato, Noriyuki Kuga, Katsutoshi Shirieda, Masahiro Enzaki, Yuji Nakaguchi, Yoshinobu Shimohigashi, Toshihisa Kawasaki, Masahiko Toyoda, Daisuke Kawahara, Fujio Araki, Shinji Kawamura
Recently, intensity-modulated radiation therapy (IMRT) is used worldwide, highly accurate verification of the location using image-guided radiation therapy (IGRT) has become critical. However, the use of cone-beam computed tomography (CBCT) to ascertain the location each time raises concerns about its influence on radiotherapy dosage and increased radiation exposure. The purpose of this study was to measure the absorbed dose using nine kilovoltage (kV) devices and two megavoltage (MV) devices (total 11 devices) at eight facilities, compare the absorbed dose among the devices, and assess the characteristics of the respective devices to ensure optimal clinical operation...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28428468/multicenter-investigation-of-the-effective-dose-for-whole-body-ct-scanning
#2
Toshimitsu Sato, Yukihiro Saito, Nobutoshi Saito, Makoto Ooba
OBJECTIVE: To study whether the actual radiation exposure is different between computed tomography (CT) scanners and medical centers when the same patient is scanned, we investigated the actual effective doses for a whole body (Chest-Pelvis) CT scan in a multicenter study. MATERIALS AND METHODS: Data from subjects were collected using 12 CT scanners at six medical centers in Yamagata city. Effective-dose data were acquired by scanning the same phantom (ATOM Dosimetry Phantoms Model702-B) using 120 kV tube voltage...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28427834/doped-silica-fibre-thermoluminescence-measurements-of-radiation-dose-in-the-use-of-223-ra
#3
Bradley, S F Abdul Sani, A S Siti Shafiqah, S M Collins, R P Hugtenburg, H A Abdul Rashid, Nurul Najua Zulkepely, M J Maah
Using tailor-made sub-mm dimension doped-silica fibres, thermoluminescent dosimetric studies have been performed for α-emitting sources of (223)RaCl2 (the basis of the Bayer Healthcare product Xofigo®). The use of (223)RaCl2 in the palliative treatment of bone metastases resulting from late-stage castration-resistant prostate cancer focuses on its favourable uptake in metabolically active bone metastases. Such treatment benefits from the high linear energy transfer (LET) and associated short path length (<100µm) of the α-particles emitted by (223)Ra and its decay progeny...
April 14, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28423624/assessment-of-female-breast-dose-for-thoracic-cone-beam-ct-using-mosfet-dosimeters
#4
Wenzhao Sun, Bin Wang, Bo Qiu, Jian Liang, Weihao Xie, Xiaowu Deng, Zhenyu Qi
OBJECTIVE: To assess the breast dose during a routine thoracic cone-beam CT (CBCT) check with the efforts to explore the possible dose reduction strategy. MATERIALS AND METHODS: Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were used to measure breast surface doses during a thorax kV CBCT scan in an anthropomorphic phantom. Breast doses for different scanning protocols and breast sizes were compared. Dose reduction was attempted by using partial arc CBCT scan with bowtie filter...
March 21, 2017: Oncotarget
https://www.readbyqxmd.com/read/28419323/monte-carlo-simulation-used-to-calculate-energy-correction-factor-for-thermoluminescent-dosimeters-used-by-occupational-workers-on-pediatric-exams
#5
G Hoff, D Filipov, S Paschuk, H R Schelin, V Denyak
The main objective of this work is to simulate the X-ray scattered spectra by different pediatric phantoms (simulation of children subjected to barium meal procedures) to calculate an energy correction factor (ECF) to the reading of thermoluminescent dosimeters (TLDs). To perform this evaluation, the TLDs were positioned over three areas in two occupational workers: eyes, thyroid and hands. The Geant4 toolkit was used to define the spectra collected by TLDs, making possible to calculate the ECF. This work was developed in two stages: (1) evaluation of scattered spectra by different standard phantoms (newborn, 1, 5 and 10 years old); (2) definition of the ECF to the absorbed energy by each TLD...
April 13, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28416994/the-radiation-safety-education-and-the-pain-physicians-efforts-to-reduce-radiation-exposure
#6
Tae Hee Kim, Seung Wan Hong, Nam Sik Woo, Hae Kyoung Kim, Jae Hun Kim
BACKGROUND: C-arm fluoroscopy equipment is important for interventional pain management and can cause radiation injury to physicians and patients. We compared radiation safety education and efforts to reduce the radiation exposure of pain specialists. METHODS: A survey of 49 pain specialists was conducted anonymously in 2016. The questionnaire had 16 questions. That questionnaire was about radiation safety knowledge and efforts to reduce exposure. We investigated the correlation between radiation safety education and efforts of radiation protection...
April 2017: Korean Journal of Pain
https://www.readbyqxmd.com/read/28411535/thermally-enhanced-tld-output-impacts-on-the-response-curve
#7
H A Soliman, Mohamed A Hassan, Enas Esmat, A M Sadek, Ahmed M Maghraby
Pre-irradiation background reading of thermoluminescent LiF dosimeters results in severe changes in the glow curve qualitatively and quantitatively. Current work focuses on the possible changes in the response of TLD-700 dosimeters after this effect. This work examines changes in the level of the glow curve as a whole and on the level of individual peaks as well. It was found that the response of TLD-700 dosimeters has increased by factors ranging from 20% to 44% in terms of area under the glow curve. Changes in individual peaks were examined by performing deconvolution for the glow curves...
April 5, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28410690/eye-lens-dose-correlations-with-personal-dose-equivalent-and-patient-exposure-in-paediatric-interventional-cardiology-performed-with-a-fluoroscopic-biplane-system
#8
L Alejo, C Koren, E Corredoira, F Sánchez, J Bayón, A Serrada, E Guibelalde
PURPOSE: To analyse the correlations between the eye lens dose estimates performed with dosimeters placed next to the eyes of paediatric interventional cardiologists working with a biplane system, the personal dose equivalent measured on the thorax and the patient dose. METHODS: The eye lens dose was estimated in terms of Hp(0.07) on a monthly basis, placing optically stimulated luminescence dosimeters (OSLDs) on goggles. The Hp(0.07) personal dose equivalent was measured over aprons with whole-body OSLDs...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28410689/photoneutron-depth-dose-equivalent-distributions-in-high-energy-x-ray-medical-accelerators-by-a-novel-position-sensitive-dosimeter
#9
Amir Hakimi, Mehdi Sohrabi
PURPOSE: The purpose of this study was to; (1) investigate employing a novel position-sensitive mega-size polycarbonate (MSPC) dosimeter for photoneutron (PN) depth, profile and dose equivalent distributions studies in a multilayer polyethylene phantom in a Siemens ONCOR accelerator, and (2) develop depth dose equivalent distribution matrix data at different depths and positions of the phantom for patient PN dose equivalent determination and in particular for PN secondary cancer risk estimation...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28410678/novel-6mv-x-ray-photoneutron-detection-and-dosimetry-of-medical-accelerators
#10
Mehdi Sohrabi, Amir Hakimi
PURPOSE: Dosimetry of fast, epithermal and thermal photoneutrons in 6MV X-ray beams of two medical accelerators were studied by novel dosimetry methods. METHODS: A Siemens ONCOR and an Elekta COMPACT medical accelerators were used. Fast, epithermal and thermal photoneutron dose equivalents in 10cm×10cm 6MV X-rays fields were determined in air and on surface of a polyethylene phantom in X and Y directions. Polycarbonate dosimeters as bare or with enriched (10)B convertors (with or without cadmium covers) were used applying a 50Hz-HV electrochemical etching method...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28405107/response-of-nanodot-optically-stimulated-luminescence-dosimeters-to-therapeutic-electron-beams
#11
Y Retna Ponmalar, Ravikumar Manickam, S Sathiyan, K M Ganesh, R Arun, Henry Finlay Godson
Response of Al2O3:C-based nanoDot optically stimulated luminescence (OSL) dosimeter was studied for the dosimetry of 6, 9, 12, 16, and 20 MeV therapeutic electron beams. With reference to ionization chamber, no change in the response was observed with the change in the energy of electron beams for the field size from 6 cm × 6 cm to 25 cm × 25 cm, dose rates from 100 MU/min to 600 MU/min, and the linearity in the response up to 300 cGy. The fading of the transient signal was higher for 20 MeV electron beam than that of 6 MeV electron beam by about 5% as compared to value at 20 min after irradiation...
January 2017: Journal of Medical Physics
https://www.readbyqxmd.com/read/28405102/measurement-of-total-scatter-factor-for-stereotactic-cones-with-plastic-scintillation-detector
#12
Suresh H Chaudhari, Rishabh Dobhal, Rajesh A Kinhikar, Sudarshan S Kadam, Deepak D Deshpande
Advanced radiotherapy modalities such as stereotactic radiosurgery (SRS) and image-guided radiotherapy may employ very small beam apertures for accurate localized high dose to target. Accurate measurement of small radiation fields is a well-known challenge for many dosimeters. The purpose of this study was to measure total scatter factors for stereotactic cones with plastic scintillation detector and its comparison against diode detector and theoretical estimates. Measurements were performed on Novalis Tx(™) linear accelerator for 6MV SRS beam with stereotactic cones of diameter 6 mm, 7...
January 2017: Journal of Medical Physics
https://www.readbyqxmd.com/read/28396725/three-dimensional-radiation-dosimetry-using-polymer-gel-and-solid-radiochromic-polymer-from-basics-to-clinical-applications
#13
REVIEW
Yoichi Watanabe, Leighton Warmington, N Gopishankar
Accurate dose measurement tools are needed to evaluate the radiation dose delivered to patients by using modern and sophisticated radiation therapy techniques. However, the adequate tools which enable us to directly measure the dose distributions in three-dimensional (3D) space are not commonly available. One such 3D dose measurement device is the polymer-based dosimeter, which changes the material property in response to radiation. These are available in the gel form as polymer gel dosimeter (PGD) and ferrous gel dosimeter (FGD) and in the solid form as solid plastic dosimeter (SPD)...
March 28, 2017: World Journal of Radiology
https://www.readbyqxmd.com/read/28390549/analysis-of-effective-and-organ-dose-estimation-in-ct-when-using-ma-modulation-a-single-scanner-pilot-study
#14
A Tootell, K Szczepura, P Hogg
INTRODUCTION: Effective dose (ED) estimation in CT examinations can be obtained by combining dose length product (DLP) with published ED per DLP coefficients or performed using software. These methods do not account for tube current (mA) modulation which is influenced by patient size. The aim of the work was to compare different methods of organ and ED estimation to measured values when using mA modulation in CT chest, abdomen and pelvis examinations. METHOD: Organ doses from CT of the chest, abdomen and pelvis were measured using digital dosimeters and a dosimetry phantom...
May 2017: Radiography
https://www.readbyqxmd.com/read/28387195/orthopedic-surgeons-knowledge-regarding-risk-of-radiation-exposition-a-survey-analysis
#15
Nejat Tunçer, Ersin Kuyucu, Şafak Sayar, Gökhan Polat, İrem Erdil, İbrahim Tuncay
INTRODUCTION: The purpose of this study is to evaluate the knowledge levels of orthopedic surgeons working in Turkey about the uses and possible risks of fluoroscopy and assess methods for preventing radiation damage. METHODS: A questionnaire with a total of 12 questions was sent to 1121 orthopedic surgeons working in Turkey. The questionnaire evaluated participants' knowledge about the uses and risks of fluoroscopy and methods for preventing damage. One thousand and twenty-four orthopedic surgeons were found to be suitable for inclusion in the study...
2017: SICOT-J
https://www.readbyqxmd.com/read/28375324/optical-performance-characterization-of-light-logging-actigraphy-dosimeters
#16
Luke L A Price, Andrey Lyachev, Marina Khazova
There are several wearable products specially developed or marketed for studying sleep, circadian rhythms, and light levels. However, new recommendations relating to human physiological responses to light have changed what measurements researchers may demand. The performances of 11 light-logging dosimeters from eight manufacturers were compared. The directional and spectral sensitivities, linearity, dynamic range, and resolution were tested for seven models, and compared along with other published data. The sample mainly comprised light-logging actigraphy dosimeters wearable as badges, in accordance with measurement protocols for larger-scale field studies...
April 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
https://www.readbyqxmd.com/read/28373715/occupational-eye-dose-in-interventional-cardiology-procedures
#17
Yoshihiro Haga, Koichi Chida, Yuji Kaga, Masahiro Sota, Taiichiro Meguro, Masayuki Zuguchi
It is important to measure the radiation dose [3-mm dose equivalent, Hp(3)] in the eye. This study was to determine the current occupational radiation eye dose of staff conducting interventional cardiology procedures, using a novel direct eye dosimeter. We measured the occupational eye dose [Hp(3)] in physicians and nurses in a catheterization laboratory for 6-months. The eye doses [Hp(3)] of 12 physicians (9 with Pb glasses, 3 without), and 11 nurses were recorded using a novel direct eye dosimeter, the DOSIRIS(TM)...
April 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28365888/cone-beam-computed-tomography-for-dental-and-maxillofacial-imaging-technique-improvement-and-low-dose-protocols
#18
Beatrice Feragalli, Osvaldo Rampado, Cecilia Abate, Monica Macrì, Felice Festa, Francesco Stromei, Sergio Caputi, Giuseppe Guglielmi
OBJECTIVE: The aim of this study was to evaluate images quality and radiation doses of Cone Beam Computed Tomography (CBCT) for dental and maxillofacial imaging testing five different acquisition protocols. METHODS: Dose measurements of different acquisition protocols were calculated for Pax Zenith three-dimensional (3D) Cone Beam (Vatech, Korea) and for conventional orthopantomography (OPT) and cephalometric skull imaging Ortophos (Sirona Dental Systems, Bernsheim, Germany)...
April 1, 2017: La Radiologia Medica
https://www.readbyqxmd.com/read/28362769/ultracompact-x-ray-dosimeter-based-on-scintillators-coupled-to-a-nano-optical-antenna
#19
Zhihua Xie, Hichem Maradj, Miguel-Angel Suarez, Lydie Viau, Virginie Moutarlier, Claudine Filiatre, Carole Fauquet, Didier Tonneau, Thierry Grosjean
We show that nano-optical antennas are capable of controlling the luminescence induced by the absorption of x rays into matter. The x-ray-excited luminescence from a tiny scintillation cluster coupled to a horn nano-optical antenna is highly directed and determined by the antenna's geometrical parameters. Directionality is sufficiently high to efficiently outcouple the x-ray-excited luminescence to a narrow single-mode optical fiber, thus enabling ultracompact fiber-integrated x-ray sensors. Our nano-optically driven approach offers the possibility of x-ray profiling and dosimetry in ultra-confined environments, opening up new avenues in the fields of x-ray imaging, as well as medical and industrial endoscopy...
April 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28361478/commissioning-a-hobby-cutting-device-for-radiochromic-film-preparation
#20
Somayeh Zolfaghari, Kirby E Francis, Tanya Kairn, Scott B Crowe
In addition to a high spatial resolution and well characterised dose response, one of the major advantages of radiochromic film as a dosimeter is that sheets of film can be cut into pieces suitable for use as calibration films, and for in vivo and phantom measurements. The cutting of film is typically done using scissors or a guillotine, and this process can be time-consuming, limited in precision, requires extensive handling and does not allow holes to be cut from the film without cutting from an existing edge...
March 30, 2017: Australasian Physical & Engineering Sciences in Medicine
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