keyword
MENU ▼
Read by QxMD icon Read
search

Radiation dose measurements

keyword
https://www.readbyqxmd.com/read/28104643/reduced-patient-radiation-exposure-during-neurodiagnostic-and-interventional-x-ray-angiography-with-a-new-imaging-platform
#1
K van der Marel, S Vedantham, I M J van der Bom, M Howk, T Narain, K Ty, A Karellas, M J Gounis, A S Puri, A K Wakhloo
BACKGROUND AND PURPOSE: Advancements in medical device and imaging technology as well as accruing clinical evidence have accelerated the growth of the endovascular treatment of cerebrovascular diseases. However, the augmented role of these procedures raises concerns about the radiation dose to patients and operators. We evaluated patient doses from an x-ray imaging platform with radiation dose-reduction technology, which combined image noise reduction, motion correction, and contrast-dependent temporal averaging with optimized x-ray exposure settings...
January 19, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28104641/measured-head-ct-cta-skin-dose-and-intensive-care-unit-patient-cumulative-exposure
#2
R D Nawfel, G S Young
BACKGROUND AND PURPOSE: Estimates of cumulative CT/CTA radiation dose based on volumetric CT dose index have raised concern that neurological intensive care unit patient exposures may reach thresholds for deterministic skin injury. Because the accuracy of volumetric CT dose index for this purpose in unknown, we set out to directly measure head CT and CTA peak skin dose, assess the relationship of volumetric CT dose index to measured peak skin dose, and determine whether multiple CT/CTA exposures in typical patients in the neurological intensive care unit produce cumulative doses approaching or exceeding single-dose deterministic thresholds for skin injury...
January 19, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28102956/experimental-verification-of-4d-monte-carlo-simulations-of-dose-delivery-to-a-moving-anatomy
#3
Sara Gholampourkashi, Miro Vujicic, Jason Belec, Joanna E Cygler, Emily Heath
PURPOSE: To evaluate a novel 4D Monte Carlo simulation tool by comparing calculations to physical measurements using a respiratory motion phantom. METHODS: We used a dynamic Quasar phantom in both stationary and breathing states (sinusoidal motion of amplitude of 1.8 cm and period of 3.3 s) for dose measurements on an Elekta Agility linear accelerator. Gafchromic EBT3 film and the RADPOS 4D dosimetry system were placed inside the lung insert of the phantom to measure dose profiles and point-dose values at the center of the spherical tumor inside the insert...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102954/dosimetric-impact-of-lipiodol-in-stereotactic-body-radiation-therapy-on-liver-after-trans-arterial-chemoembolization
#4
Daisuke Kawahara, Shuichi Ozawa, Akito Saito, Teiji Nishio, Tomoki Kimura, Tatsuhiko Suzuki, Kazunari Hioki, Takeo Nakashima, Yoshimi Ohno, Yuji Murakami, Yasushi Nagata
PURPOSE: Stereotactic body radiation therapy (SBRT) combining trans-arterial chemoembolization (TACE) with Lipiodol is expected to improve local control. This study is aimed to estimate the dose enhancement in Lipiodol's proximity and to evaluate the dose calculation accuracy of the Acuros XB (AXB) algorithm and anisotropic analytical algorithm (AAA) in the Eclipse treatment planning system (TPS) (ver. 11, Varian Medical Systems, Palo Alto, USA), compared with that of the Monte Carlo (MC) calculation (using BEAMnrc/DOSXYZnrc code) for a virtual phantom and a treatment plan for liver SBRT after TACE...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102953/air-kerma-strength-determination-of-an-hdr-192-ir-source-including-a-geometric-sensitivity-study-of-the-seven-distance-method
#5
Blake R Smith, John A Micka, Manik Aima, Larry A DeWerd, Wesley S Culberson
PURPOSE: To perform an in-air air-kerma strength (SK) calibration of the Bebig model Ir2.A85-2 192Ir high-dose rate (HDR) brachytherapy source manufactured by Mallinckrodt Medical (Westerduinweg, Germany) with the NIST-traceable seven-distance technique established by the University of Wisconsin. A comparison was made between the reference air-kerma rate (RAKR) reported on a certificate from the Physikalisch-Technische Bundesanstalt (Berlin, Germany) (PTB) primary laboratory and the SK determined at the University of Wisconsin Madison Radiation Research Center (UWMRRC)...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102948/use-of-parallel-plate-ionization-chambers-in-reference-dosimetry-of-novac-and-liac-%C3%A2-mobile-electron-linear-accelerators-for-intraoperative-radiotherapy-a-multi-center-survey
#6
Paolo Scalchi, Alessia Ciccotelli, Giuseppe Felici, Assunta Petrucci, Raffaella Massafra, Valeria Piazzi, Paola D'Avenia, Francesca Cavagnetto, Federica Cattani, Raffaella Romagnoli, Antonella Soriani
PURPOSE: LIAC(®) and NOVAC are two mobile linear accelerators dedicated to intraoperative radiation therapy (IORT), generating electron beams in the energy range of 3-12 MeV. Due to high dose-per-pulse (up to 70 mGy per pulse), in 2003 the Italian National Institute of Health (ISS) stated that "for the measure of dose to water in reference conditions, ionization chambers cannot be employed and no published dosimetry protocol can be used". As a consequence, ferrous sulphate (or, alternatively alanine) dosimetry was recommended...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102946/a-portal-dosimetry-dose-prediction-method-based-on-collapsed-cone-algorithm-using-the-clinical-beam-model
#7
J Martínez Ortega, N Gómez González, P Castro Tejero, M Pinto Monedero, N B Tolani, L Núñez Martín, R Sánchez Montero
PURPOSE: Amorphous silicon electronical portal imaging devices (EPIDs) are widely used for dosimetric measurements in Radiation Therapy. The purpose of this work was to determine if a portal dose prediction method can be utilized for dose map calculations based on the linear accelerator model within a commercial treatment planning system (Pinnacle(3) v8.0 m). METHODS: The method was developed for a 6 MV photon beam on the Varian Clinac 21-EX, at a nominal dose rate of 400 MU/min...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102944/a-simple-and-robust-trajectory-based-stereotactic-radiosurgery-treatment
#8
Byron Wilson, Karl Otto, Ermias Gete
INTRODUCTION: We present a Trajectory-based Volumetric Modulated Arc Therapy (TVMAT) technique for Stereotactic Radiosurgery (SRS) that takes advantage of a modern linacs ability to modulate dose rate and move the couch dynamically. In addition, we investigate the quality of the developed TVMAT method and the dosimetric accuracy of the technique. METHODS: The main feature of the TVMAT technique is a standard beam trajectory formed by dynamic motion of the treatment couch and the linac gantry...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102497/regulated-partitioning-of-fixed-carbon-14-c-sodium-na-potassium-k-and-glycine-betaine-determined-salinity-stress-tolerance-of-gamma-irradiated-pigeonpea-cajanus-cajan-l-millsp
#9
Pankaj Kumar, Vasundhara Sharma, Chobhe Kapil Atmaram, Bhupinder Singh
Soil salinity is a major constraint that limits legume productivity. Pigeonpea is a salt sensitive crop. Seed gamma irradiation at a very low dose (2.5 Gy) is known to enhance seedling establishment, plant growth and yield of cereals and other crops. The present study conducted using two genetically diverse varieties of pigeonpea viz., Pusa-991 and Pusa-992 aimed at establishing the role of pre-sowing seed gamma irradiation at 0, 0.0025, 0.005, 0.01, 0.02, 0.05 and 0.1 kGy on plant growth, seed yield and seed quality under salt stress at 0, 80 and 100 mM NaCl (soil solution EC equivalent 1...
January 19, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28102439/reconstruction-of-radionuclide-intakes-for-the-residents-of-east-urals-radioactive-trace-1957-2011
#10
Evgenia I Tolstykh, Lyudmila M Peremyslova, Marina O Degteva, Bruce A Napier
The East Urals Radioactive Trace (EURT) was formed after a chemical explosion in the radioactive waste-storage facility of the Mayak Production Association in 1957 (Southern Urals, Russia) and resulted in an activity dispersion of 7.4 × 10(16) Bq into the atmosphere. Internal exposure due to ingestion of radionuclides with local foodstuffs was the main factor of public exposure at the EURT. The EURT cohort, combining residents of most contaminated settlements, was formed for epidemiological study at the Urals Research Center for Radiation Medicine, Russia (URCRM)...
January 19, 2017: Radiation and Environmental Biophysics
https://www.readbyqxmd.com/read/28099164/investigation-of-time-resolved-proton-radiography-using-x-ray-flat-panel-imaging-system
#11
Kyung-Wook Jee, Rongxiao Zhang, El Bentefour, Paul Doolan, Ethan Cascio, Gregory Sharp, Jacob Flanz, Hsiao-Ming Lu
Proton beam therapy benefits from the Bragg peak and delivers highly conformal dose distributions. However, the location of the end-of-range is subject to uncertainties related to the accuracy of the relative proton stopping power estimates and thereby the water-equivalent path length (WEPL) along the beam. To remedy the range uncertainty, an in vivo measurement of the WEPL through the patient, i.e. a proton-range radiograph, is highly desirable. Towards that goal, we have explored a novel method of proton radiography based on the time-resolved dose measured by a flat panel imager (FPI)...
January 18, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28098666/estimated-internal-and-external-radiation-exposure-of-caregivers-of-patients-with-pediatric-neuroblastoma-undergoing-131i-metaiodobenzylguanidine-therapy-a-prospective-pilot-study
#12
Sangwon Han, Seon Hee Yoo, Kyung-Nam Koh, Jong Jin Lee
PURPOSE: Current recommendations suggest that family members should participate in the care of children receiving in-hospital I metaiodobenzylguanidine (MIBG) therapy for neuroblastoma. The present study aimed to measure the external radiation exposure and estimate the internal radiation exposure of caregivers during the hospital stay for I MIBG therapy. MATERIALS AND METHODS: Caregivers received radiation safety instructions and a potassium iodide solution for thyroid blockade before patient admission...
January 16, 2017: Clinical Nuclear Medicine
https://www.readbyqxmd.com/read/28097674/monte-carlo-simulations-of-ceiling-scatter-in-nuclear-medicine-99m-tc-131-i-and-18-f
#13
Roald S Schnerr, Anouk N de Jong, Guillaume Landry, Cécile R L P N Jeukens, Roel Wierts
PURPOSE: In the design of nuclear medicine treatment and examination rooms, an important consideration is the shielding required for ionizing radiation from the radioactive isotopes used. The shielding in the walls is normally limited to a height lower than the actual ceiling height. The direct radiation, possibly with build-up correction, can be calculated relatively easily. However, little data is available to estimate the dose contribution from ionizing radiation traveling over the wall shielding and scattering off the ceiling...
January 18, 2017: Medical Physics
https://www.readbyqxmd.com/read/28094849/the-collimator-monitoring-fill-factor-of-a-two-dimensional-detector-array-a-measure-of-its-ability-to-detect-collimation-errors
#14
Tenzin Sonam Stelljes, Hui Khee Looe, Dietrich Harder, Björn Poppe
PURPOSE: Two-dimensional detector arrays are routinely used for constancy checks and treatment plan verification in photon-beam radiotherapy. In addition to the spatial resolution of the dose profiles, the "coverage" of the radiation field with respect to the detection of any beam collimation deficiency appears as the second characteristic feature of a detector array. The here proposed "collimator monitoring fill factor" (CM fill factor) has been conceived to serve as a quantitative characteristic of this "coverage"...
January 17, 2017: Medical Physics
https://www.readbyqxmd.com/read/28094215/effect-of-decompression-for-patients-with-various-jaw-cysts-based-on-a-three-dimensional-computed-tomography-analysis
#15
Ho-Gul Jeong, Jae Joon Hwang, Sung Hwa Lee, Woong Nam
OBJECTIVES: The aim of this study is to evaluate the effectiveness of decompression according to reduction parameters by measuring cystic volume changes using computed tomography (CT). STUDY DESIGN: We chose patients who had undergone decompression for a cystic lesion of the jaw at the Department of Oral and Maxillofacial Surgery in our dental hospital between 2006 and 2015. All patients had been examined by CT before and after decompression. We measured the volume of cystic lesions using the threshold method and evaluated the volumetric changes after decompression according to various parameters...
December 7, 2016: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
https://www.readbyqxmd.com/read/28094209/simplified-low-dose-rate-infant-total-body-irradiation
#16
Nels Knutson, Y James Rao, Sridhar Yaddanapudi, Stephanie M Perkins, H Harold Li
PURPOSE: Low-dose-rate total body irradiation (LDR TBI) in infants possesses unique challenges because of the setup limitations imposed by anesthesia. We present an LDR TBI method with an anteroposterior/posteroanterior arrangement and dose rate < 10 cGy/minute for infants (thickness <14 cm) without the use of a beam attenuator. MATERIALS AND METHODS: The delivery used a 6 MV TrueBeam linear accelerator (Varian Medical Systems, Palo Alto, CA) with adjustable meterset rates below 100 MU/minute...
October 24, 2016: Practical Radiation Oncology
https://www.readbyqxmd.com/read/28094138/new-normoxic-n-hydroxymethyl-acrylamide-based-polymer-gel-for-3d-dosimetry-in-radiation-therapy
#17
Khalid A Rabaeh, Ahmed A Basfar, Akram A Almousa, Slobodan Devic, Belal Moftah
A novel composition of normoxic polymer gel dosimeters based on radiation-induced polymerization of N-(Hydroxymethyl)acrylamide (NHMA) is introduced in this study for 3D dosimetry for Quality Assurance (QA) in radiation therapy. Dosimeters were irradiated by 6, 10 and 18MV photon beams of a medical linear accelerator at various dose rates to doses of up to 20Gy. The dose response of polymer gel dosimeters was studied using nuclear magnetic resonance (NMR) spin-spin relaxation rate (R2) of hydrogen protons within the water molecule...
January 13, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28091978/patient-specific-optimisation-of-administered-activity-and-acquisition-times-for-18-f-fdg-pet-imaging
#18
Fred Wickham, Helena McMeekin, Maria Burniston, Daniel McCool, Deborah Pencharz, Annah Skillen, Thomas Wagner
BACKGROUND: The purpose of this study is to identify a method for optimising the administered activity and acquisition time for (18)F-FDG PET imaging, yielding images of consistent quality for patients with varying body sizes and compositions, while limiting radiation doses to patients and staff. Patients referred for FDG scans had bioimpedance measurements. They were injected with 3 MBq/kg of (18)F up to 370 MBq and scanned on a Siemens Biograph mCT at 3 or 4 min per bed position...
December 2017: EJNMMI Research
https://www.readbyqxmd.com/read/28089526/a-feasibility-study-of-2-mm-bolus-for-postmastectomy-radiation-therapy
#19
Lauren C Das, Daniel W Golden, Eugenia Perevalova, Anthony C Wong, Kimberly De Nardo, Christopher Stepaniak, Daniel S Joyce, Bradley P McCabe, Yasmin Hasan, Steven J Chmura, Anne McCall
PURPOSE: The purpose of this study was to prospectively evaluate the use of daily 2-mm bolus in patients undergoing postmastectomy radiation without reconstruction using optically stimulated luminescence dosimetry and weekly assessment of skin toxicity. METHODS AND MATERIALS: We prospectively collected data from the first 49 women treated with a daily 2-mm Superflab bolus during their postmastectomy radiation therapy from 2013 to 2016 at The University of Chicago Comprehensive Cancer Center at Silver Cross...
October 24, 2016: Practical Radiation Oncology
https://www.readbyqxmd.com/read/28089106/-edge-on-moskin-detector-for-stereotactic-beam-measurement-and-verification
#20
Wei Loong Jong, Ngie Min Ung, Ath Vannyat, Zulaikha Jamalludin, Anatoly Rosenfeld, Jeannie Hsiu Ding Wong
Dosimetry in small radiation field is challenging and complicated because of dose volume averaging and beam perturbations in a detector. We evaluated the suitability of the "Edge-on" MOSkin (MOSFET) detector in small radiation field measurement. We also tested the feasibility for dosimetric verification in stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT). "Edge-on" MOSkin detector was calibrated and the reproducibility and linearity were determined. Lateral dose profiles and output factors were measured using the "Edge-on" MOSkin detector, ionization chamber, SRS diode and EBT2 film...
January 6, 2017: Physica Medica: PM
keyword
keyword
6437
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"