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Theodore Hughes-Riley, Tilak Dias
Overexposure to high levels of noise can cause permanent hearing disorders, which have a significant adverse effect on the quality of life of those affected. Injury due to noise can affect people in a variety of careers including construction workers, factory workers, and members of the armed forces. By monitoring the noise exposure of workers, overexposure can be avoided and suitable protective equipment can be provided. This work focused on the creation of a noise dosimeter suitable for use by members of the armed forces, where a discrete dosimeter was integrated into a textile helmet cover...
May 17, 2018: Sensors
Marioly Vernhes Tamayo, André Passaglia Schuch, Teiti Yagura, Luis Baly Gil, Carlos Frederico Martins Menck, Angel Sánchez-Lamar
One approach to protect the human skin against harmful effects of solar ultraviolet (UV) radiation is to use natural products as photoprotectors. In this work, the extract from specie Phyllanthus orbicularis K was evaluated as a protective agent against the photodamage by UVB, UVA artificial lamps and environmental sunlight exposure. The plasmid DNA solutions were exposed to radiations using the DNA-dosimeter system in presence of plant extract. The DNA repair enzymes, E. coli Formamidopyrimidine-DNA glycosylase (Fpg) and T4 bacteriophage endonuclease V (T4-endo V), were employed to discriminate oxidized DNA damage and cyclobutane pyrimidine dimers (CPD) respectively...
May 16, 2018: Photochemistry and Photobiology
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
Críssia Carem Paiva Fontainha, Neriene Alves, Wilmar Barbosa Ferraz, Luiz Oliveira de Faria
New materials have been widely investigated for ionizing radiation dosimetry for medical procedures. Carbon-doped alumina (α-Al2 O3 :C) have been reported to be excellent thermoluminescent (TL) and optically stimulated luminescence (OSL) radiation dosimeters. In the present study, we have synthetized nano and micro-sized α-Al2 O3 :C polycrystals, doped with different percentages of carbon atoms aiming to compare their efficiency as TL dosimeters. The dosimetric characteristics for X ray and gamma fields were investigated...
May 7, 2018: Applied Radiation and Isotopes
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
Carlos Ubeda, Claudio Morales, Diego Gutiérrez, Marcus Oliveira, Carlos Manterola
The objective of this article is to present initial occupational dose values using digital active personal dosimeters for medical staff during adult interventional cardiology procedures in a public hospital in Chile. Personal dose equivalent Hp(10) over the lead apron of physician, nurse and radiographer were measured during 59 procedures. Mean values of occupational dose Hp(10) per procedure were 47.6, 6.2 and 4.3 μSv for physician, nurse and radiographer, respectively. If no protective tools are used, physician dose can exceed the new eye lens dose limit...
May 11, 2018: Radiation Protection Dosimetry
M Rejab, J H D Wong, Z Jamalludin, W L Jong, R A Malik, W Z Wan Ishak, N M Ung
This study investigates the characteristics and application of the optically-stimulated luminescence dosimeter (OSLD) in cobalt-60 high dose rate (HDR) brachytherapy, and compares the results with the dosage produced by the treatment planning system (TPS). The OSLD characteristics comprised linearity, reproducibility, angular dependence, depth dependence, signal depletion, bleaching rate and cumulative dose measurement. A phantom verification exercise was also conducted using the Farmer ionisation chamber and in vivo diodes...
May 13, 2018: Australasian Physical & Engineering Sciences in Medicine
Konard Schuetze, A Eickhoff, C Dehner, M Schultheiss, F Gebhard, P H Richter
Hybrid-operating rooms enable the surgeon to acquire intraoperative high-resolution 2- and 3D images and use them for navigation. The radiation dose of the operating personal and the patient remains the major concern. In 9 months, 109 pelvic and spine cases were performed using a hybrid operating room. Radiation dose of the surgeon and the assisting nurse was recorded using real-time dosimeters. Lower radiation doses for the main surgeon in navigated dorsal instrumentations of the thoracic spine were recorded...
May 10, 2018: Journal of Robotic Surgery
Chuanlei Liu, Weihua Zhang, Kurt Ungar, Ed Korpach, Brian White, Mike Benotto, Eric Pellerin
This work explores the application of Health Canada's Fixed Point Surveillance (FPS) network for cosmic ray monitoring and dose estimation purposes. This network is comprised of RS250 3 inch by 3 inch Sodium Iodide (NaI) spectroscopic dosimeters distributed throughout Canada. The RS250's high channel count rate responds to the electromagnetic and muonic components of cosmic ray shower. These count rates are used to infer cosmic ray doses throughout FPS locations. The derived dose was found to have an accuracy within 6...
May 7, 2018: Journal of Environmental Radioactivity
Yong Hum Na, Yi-Fang Wang, Paul J Black, Christian Velten, Xin Qian, Shih-Chi Lin, John Adamovics, Cheng-Shie Wuu
PURPOSE: The precise dosimetric and geometric characteristics of small animal irradiators are essential to achieving reproducible dose delivery, especially in cases where image-guidance is utilized. Currently, radiochromic film is the established measurement tool used to evaluate beam characteristics for these systems. However, only 2D information can be acquired with film. This study characterized both the dosimetric and geometric properties of the small animal research radiation platform (SARRP, Xstrahl) for commissioning purposes using a 3D radiochromic dosimetry system with a sub-millimeter resolution optical computed tomography (OCT) scanner...
May 10, 2018: Medical Physics
Mohammad Obeidat, Kristen A McConnell, Xiaolei Li, Brian Bui, Sotiris Stathakis, Niko Papanikolaou, Karl Rasmussen, Chul Soo Ha, Sang Eun Lee, Eun Yong Shim, Neil Kirby
PURPOSE: Many types of dosimeters are used to measure radiation dose and calibrate radiotherapy equipment, but none directly measure the biological effect of this dose. The purpose here is to create a dosimeter that can measure the probability of double-strand breaks (DSB) for DNA, which is directly related to the biological effect of radiation. METHODS: A DNA dosimeter, consisting of magnetic streptavidin beads attached to 4 kilobase pair DNA strands labeled with biotin and fluorescein amidite (FAM) on opposing ends, was suspended in phosphate-buffered saline (PBS)...
May 10, 2018: Medical Physics
Fatima M Jadu, Asmaa A Alzahrani, Maha A Almutairi, Salma O Al-Amoudi, Ahmed M Jan, Mawya A Khafaji
To investigate changes in the effective radiation dose (E) in relation to variations in voxel (VOX) size settings and the field-of-view (FOV) centralization. Methods: This cross-sectional dosimetry study used nanoDot OSLD dosimeters placed at 25 pre-determined sites in the head and neck slices of a RANDO male phantom to measure the absorbed radiation. The imaging scans took place at King Abdulaziz University Dental Hospital, Jeddah, Saudi Arabia between September 2016 and May 2017 using the i-CAT classic cone beam computed tomography (CBCT)  unit...
May 2018: Saudi Medical Journal
Satoshi Fujita, Eitaro Fujii, Yoshihiko Kagawa, Katsuhiro Inoue, Tsuyoshi Yamada, Masaaki Ito
It is important to visually confirm radiofrequency ablation lesions during atrial fibrillation (AF) ablation for procedural efficiency, which requires the integration of a three-dimensional (3D) left atrial image reconstructed from computed tomography (CT) or a magnetic resonance imaging. However, an EP Navigator allows seamless integration of 3D anatomy obtained through 3D rotational angiography (3D-ATG) into an electroanatomical mapping system. We hypothesized that 3D-ATG can be used during AF ablation while significantly reducing the effective dose (ED) and without compromising image morphology compared to a 3D-CT image...
May 7, 2018: Heart and Vessels
Hiroyuki Okamoto, Toshiyuki Minemura, Mitsuhiro Nakamura, Hideyuki Mizuno, Naoki Tohyama, Teiji Nishio, Akihisa Wakita, Satoshi Nakamura, Shie Nishioka, Kotaro Iijima, Daisuke Fujiyama, Jun Itami, Yasumasa Nishimura
We developed an efficient postal audit system to independently assess the delivered dose using radiophotoluminescent glass dosimeters (RPLDs) and the positional differences of fields using EBT3 film at the axial plane for intensity-modulated radiotherapy (IMRT). The audit phantom had a C-shaped target structure as a planning target volume (PTV) with four measurement points for the RPLDs and a cylindrical structure as the organ at risk (OAR) for one measurement point. The phantoms were sent to 24 institutions...
April 2018: Physica Medica: PM
Touko Kaasalainen, Teemu Mäkelä, Anna Kelaranta, Mika Kortesniemi
RATIONALE AND OBJECTIVES: This phantom study aimed to evaluate low-dose (LD) chest computed tomography (CT) protocols using model-based iterative reconstruction (MBIR) for diagnosing lung metastases in patients with sarcoma. MATERIALS AND METHODS: An adult female anthropomorphic phantom was scanned with a 64-slice CT using four LD protocols and a standard-dose protocol. Absorbed organ doses were measured with 10 metal-oxide-semiconductor field-effect transistor dosimeters...
April 30, 2018: Academic Radiology
Daniel Benchimol, Nils Kadesjö, Juha Koivisto, Xie-Qi Shi
OBJECTIVES: The primary aim was to evaluate the effective dose for a full size panoramic image and nine different panoramic protocols using collimation. The secondary aim was to estimate possible reduction of effective dose in clinical situations. METHODS: Effective dose, according to International Commission on Radiological Protection (ICRP) 2007, were determined for a full size panoramic image and nine different panoramic protocols applying collimation on an anthropomorphic Rando phantom, using metal-oxide semiconductor field-effect transistor (MOSFET) dosimeters...
May 3, 2018: Dento Maxillo Facial Radiology
M Portelli, A Militi, A Lo Giudice, R Lo Giudice, R Fastuca, I Ielo, V Mongelli, G Lo Giudice, A Martintoni, M Manuelli, A Lucchese, R Nucera
Considering the diagnostic capability offered by cone-beam computed tomography (CBCT), nowadays orthodontists often use this exam for treatment planning, especially in cases of impacted teeth, maxillary ipoplasia, orthognathic surgery etc. The aim of this study was to compare the radiation doses related to a conventional CBCT setting and that of a low dose protocol, usable in orthodontic practice. The absorbed organ doses were measured using an anthropomorphic phantom loaded with thermo-luminescent dosimeters related to sensitive organs (brain, bone marrow, salivary glands, thyroid, esophagus, oral mucosa, extrathoracic airways, lymph nodes)...
March 2018: Journal of Biological Regulators and Homeostatic Agents
Francesca Di Lillo, Giovanni Mettivier, Roberta Castriconi, Antonio Sarno, Andrew W Stevenson, Chris J Hall, Daniel Häusermann, Paolo Russo
The principle of rotational summation of the absorbed dose for breast cancer treatment with orthovoltage X-ray beams was proposed by J. Boone in 2012. Here, use of X-ray synchrotron radiation for image guided external beam rotational radiotherapy treatment of breast cancer is proposed. Tumor irradiation occurs with the patient in the prone position hosted on a rotating bed, with her breast hanging from a hole in the bed, which rotates around a vertical axis passing through the tumor site. Horizontal collimation of the X-ray beam provides for whole breast or partial breast irradiation, while vertical translation of the bed and successive rotations allow for irradiation of the full tumor volume, with dose rates which permit also hypofractionated treatments...
May 1, 2018: Journal of Synchrotron Radiation
James Archer, Enbang Li, Marco Petasecca, Andrew Stevenson, Jayde Livingstone, Andrew Dipuglia, Jeremy Davis, Anatoly Rosenfeld, Michael Lerch
Cancer is one of the leading causes of death worldwide. External beam radiation therapy is one of the most important modalities for the treatment of cancers. Synchrotron microbeam radiation therapy (MRT) is a novel pre-clinical therapy that uses highly spatially fractionated X-ray beams to target tumours, allowing doses much higher than conventional radiotherapies to be delivered. A dosimeter with a high spatial resolution is required to provide the appropriate quality assurance for MRT. This work presents a plastic scintillator fibre optic dosimeter with a one-dimensional spatial resolution of 20 µm, an improvement on the dosimeter with a resolution of 50 µm that was demonstrated in previous work...
May 1, 2018: Journal of Synchrotron Radiation
M I Ramírez-Romero, L García-Salinas, M Villicaña-Méndez, R Huirache-Acuña, J Apolinar-Cortés, P R González
This work presents the results obtained from the dosimetric properties of the new radiation detectors of KMgF3 :Tb + PTFE. The thermoluminescent material was obtained by microwave technique. The polycrystalline powder obtained was mixed with polytetrafluoroethylene resin powder in the ratio 2:3 to make dosimeters in pellet form. The thermoluminescent response of these new detectors presented a linear behavior, in the dose range between 1 and 1000 Gy 60 Co gamma radiation, the repeatability test in the measurements, during ten cycles of heat treatment, irradiation and readouts, showed ± 3...
April 6, 2018: Applied Radiation and Isotopes
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