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https://www.readbyqxmd.com/read/29759487/clinical-examination-of-proton-pencil-beam-scanning-on-a-moving-anthropomorphic-lung-phantom
#1
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/29740298/working-memory-updating-training-improves-mathematics-performance-in-middle-school-students-with-learning-difficulties
#2
Hongxia Zhang, Lei Chang, Xiaoying Chen, Liang Ma, Renlai Zhou
Working memory (WM) deficit is considered the key cause of learning difficulties (LDs). Studies have shown that WM is plastic and thus can be improved through training. This positive effect is transferable to fluid intelligence and academic performance. This study investigated whether WM updating ability and academic performance in children with LDs could be improved through WM updating training and explored the effects of this training on the children's brain activity. We used a running memory task lasting approximately 40 min per day for 28 days to train a group of 23 children with LDs (TLDs group)...
2018: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/29658781/evaluation-of-the-radiation-dose-in-the-thyroid-gland-using-different-protective-collars-in-panoramic-imaging
#3
Ladan Hafezi, Seyyedeh Marjan Arianezhad, Seyed Mahdi Hosseini Pooya
BACKGROUND: The value for the use of thyroid shield is one of the issues in radiation protection of patients in dental panoramic imaging. OBJECTIVES: The objective of this research is to investigate the attenuation characteristics of some models of thyroid shielding in dental panoramic examinations. METHODS: The effects of five different types of lead and lead-free (Pb-Equivalent) shields on dose reduction of thyroid gland were investigated using implanted TLDs in head-Neck parts of a Rando phantom...
April 16, 2018: Dento Maxillo Facial Radiology
https://www.readbyqxmd.com/read/29609825/a-patient-centric-approach-to-quality-control-and-dosimetry-in-ct-including-cbct
#4
H de Las Heras Gala, F Schöfer, H Schöfer, R M Sánchez Casanueva, C Zervides, K Mair, Q Al-Zoubi, B Renger, T de Las Heras Gala, H Schlattl
One measurement and an algebraic formula are used to calculate the incident air kerma (Ka,i ) at the skin after any CT examination, including cone-beam CT (CBCT) and multi-slice CT (MSCT). Empty scans were performed with X-ray CBCT systems (dental, C-arm and linac guidance scanners) as well as two MSCT scanners. The accumulated Ka,i at the flat panel (in CBCT) or the maximum incident air kerma at the isocentre (in MSCT) were measured using a solid-state probe. The average Ka,i (skin), at the skin of a hypothetical patient, was calculated using the proposed formula...
March 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/29581946/estimation-of-the-effective-dose-of-dental-cone-beam-computed-tomography-using-personal-computer-based-monte-carlo-software
#5
Eun-Kyung Kim, Won-Jeong Han, Jin-Woo Choi, Bulgan Battulga
Purpose: To calculate the effective doses of cone-beam computed tomography (CBCT) using personal computer-based Monte Carlo (PCXMC) software (Radiation and Nuclear Safety Authority, Helsinki, Finland) and to compare the calculated effective doses with those measured using thermoluminescent dosimeters (TLDs) and an anthropomorphic phantom. Materials and Methods: An Alphard VEGA CBCT scanner (Asahi Roentgen Ind. Co., Kyoto, Japan) with multiple fields of view (FOVs) was used for this study...
March 2018: Imaging Science in Dentistry
https://www.readbyqxmd.com/read/29578903/acceptance-testing-of-thermoluminescent-dosimeter-holders
#6
Alexander Romanyukha, Matthew D Grypp, Thad J Sharp, John N DiRito, Martin E Nelson, Stanley T Mavrogianis, Jeancarlo Torres, Luis A Benevides
The U.S. Navy uses the Harshaw 8840/8841 dosimetric (DT-702/PD) system, which employs LiF:Mg,Cu,P thermoluminescent dosimeters (TLDs), developed and produced by Thermo Fisher Scientific (TFS). The dosimeter consists of four LiF:Mg,Cu,P elements, mounted in Teflon® on an aluminum card and placed in a plastic holder. The holder contains a unique filter for each chip made of copper, acrylonitrile butadiene styrene (ABS), Mylar®, and tin. For accredited dosimetry labs, the ISO/IEC 17025:2005(E) requires an acceptance procedure for all new equipment...
May 2018: Health Physics
https://www.readbyqxmd.com/read/29566224/feasibility-study-of-using-pcxmc-2-0-to-estimate-patient-dose-arising-from-dexa-scans
#7
Hollie Harmer, Sally Radford, Mary Smail
Patients undergoing dual energy X-ray absorption (DEXA) scans are exposed to small doses of ionizing radiation. Few papers have been published on the effective dose and organ dose for patients undergoing such scans on newer DEXA scanners. PCXMC 2.0 was used to calculate adult patient dose arising from DEXA scans. PCXMC 2.0 calculations were compared to published data and a discrepancy was noted for organ dose. Following this, effective and organ dose were measured on an anthropomorphic phantom using TLDs as a second comparison...
March 16, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29509945/radiation-exposure-of-the-investigator-during-navigated-fusion-of-124iodine-pet-imaging-and-ultrasound
#8
Christian Kühnel, Thomas Winkens, Philipp Seifert, Robert Drescher, Martin Freesmeyer
To assess the radiation exposure of the investigator during navigated fusion of nuclear medicine images with ultrasound after application of I-124. Dosimetry with two different types of thermoluminescent detectors (TLD) was performed in 25 patients. The dose rate at the patient's neck was measured with a calibrated dose rate meter (DRM) and served as the standard of reference. The average exposure per investigation at the patient's neck measured by LiF:Mg,Cu,P TLDs (cumulative: 212 μSv), LiF:Mg,Ti TLDs (cumulative: 112 μSv) and DRM (cumulative: 150...
March 2, 2018: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29499614/use-of-functional-respiratory-imaging-to-characterize-the-effect-of-inhalation-profile-and-particle-size-on-lung-deposition-of-inhaled-corticosteroid-long-acting-%C3%AE-2-agonists-delivered-via-a-pressurized-metered-dose-inhaler
#9
Cedric Van Holsbeke, Jan De Backer, Wim Vos, Jonathan Marshall
BACKGROUND: Functional respiratory imaging (FRI) uses three-dimensional models of human lungs and computational fluid dynamics to simulate functional changes within airways and predict the deposition of inhaled drugs. This study used FRI to model the effects of different patient inhalation and drug formulation factors on lung deposition of an inhaled corticosteroid/long-acting β2 -agonist (ICS/LABA) combination, administered by a pressurized metered-dose inhaler. METHODS: Three-dimensional models of the lungs of six patients with asthma (mean forced expiratory volume in 1 s, 83%), treated with an ICS/LABA, were included...
January 2018: Therapeutic Advances in Respiratory Disease
https://www.readbyqxmd.com/read/29472079/thermoluminescence-dosimetry-of-the-dose-received-by-scrotum-and-testes-in-radiotherapy-of-rectal-cancer-compared-to-the-point-doses-calculated-by-3d-planning-software
#10
Peiman Haddad, Zhaleh Karimi-Moghaddam, Mahbod Esfahani, Mahdieh Afkhami, Farshid Farhan, Farnaz Amouzegar-Hashemi
PURPOSE: Radiation received by the testes in the course of radiotherapy for rectal cancer may cause oligospermia and azospermia. We sought to determine the dose to the scrotum and testes with thermoluminescence dosimetry (TLD), and compare it to the dose calculated by 3D planning software. METHODS: The TLDs were fixed to the scrotum in six points anteriorly and posteriorly in two fractions of radiotherapy. All patients received a 50-50.4 Gy total dose in prone position with 3D-planning...
January 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/29353371/a-systematic-assessment-of-google-search-queries-and-readability-of-online-gynecologic-oncology-patient-education-materials
#11
Alexandra Martin, J Ryan Stewart, Jeremy Gaskins, Erin Medlin
The Internet is a major source of health information for gynecologic cancer patients. In this study, we systematically explore common Google search terms related to gynecologic cancer and calculate readability of top resulting websites. We used Google AdWords Keyword Planner to generate a list of commonly searched keywords related to gynecologic oncology, which were sorted into five groups (cervical cancer, ovarian cancer, uterine cancer, vulvar cancer, vaginal cancer) using five patient education websites from sgo...
January 20, 2018: Journal of Cancer Education: the Official Journal of the American Association for Cancer Education
https://www.readbyqxmd.com/read/29227874/selecting-passive-dosimetry-technologies-for-measuring-the-external-dose-of-terrestrial-wildlife
#12
REVIEW
Phakphum Aramrun, Nicholas A Beresford, Michael D Wood
Dosimeters attached to wild animals can be used to validate regulatory assessment approaches and models for estimating radiation exposure of wild animals. Such measurements are also necessary to ensure that robust dose-effect relationships can be developed from the results of field research programmes. This paper presents the first comprehensive evaluation of the different dosimetry technologies available for specifically measuring the external exposure of wildlife. Guidance is provided on the selection of appropriate passive dosimetry approaches for directly measuring external exposure of terrestrial wildlife under field conditions...
February 2018: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/29165619/comparison-of-response-of-passive-dosimetry-systems-in-scanning-proton-radiotherapy-a-study-using-paediatric-anthropomorphic-phantoms
#13
Ž Kneževic, I Ambrozova, C Domingo, M De Saint-Hubert, M Majer, I Martínez-Rovira, S Miljanic, N Mojzeszek, P Porwol, O Ploc, M Romero-Expósito, L Stolarczyk, S Trinkl, R M Harrison, P Olko
Proton beam therapy has advantages in comparison to conventional photon radiotherapy due to the physical properties of proton beams (e.g. sharp distal fall off, adjustable range and modulation). In proton therapy, there is the possibility of sparing healthy tissue close to the target volume. This is especially important when tumours are located next to critical organs and while treating cancer in paediatric patients. On the other hand, the interactions of protons with matter result in the production of secondary radiation, mostly neutrons and gamma radiation, which deposit their energy at a distance from the target...
November 18, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29164632/characterization-of-nanodot-optically-stimulated-luminescence-detectors-and-high-sensitivity-mcp-n-thermoluminescent-detectors-in-the-40-300-kvp-energy-range
#14
Yannick Poirier, Svetlana Kuznetsova, Jose Eduardo Villarreal-Barajas
PURPOSE: To investigate empirically the energy dependence of the detector response of two in vivo luminescence detectors, LiF:Mg,Cu,P (MCP-N) high-sensitivity TLDs and Al2 O3 :C OSLDs, in the 40-300-kVp energy range in the context of in vivo surface dose measurement. As these detectors become more prevalent in clinical and preclinical in vivo measurements, knowledge of the variation in the empirical dependence of the measured response of these detectors across a wide spectrum of beam qualities is important...
January 2018: Medical Physics
https://www.readbyqxmd.com/read/29155416/eye-lens-dose-monitoring-in-the-uk-nuclear-industry-using-active-personal-dosemeters
#15
Andrew Forrest McWhan, Wioletta Dobrzynska
The reduction of the dose limit for eye lens from 150 to 20 mSv year-1 must be implemented by EU member states by February 2018. Consequently, there is a requirement for all employers engaged with work with ionising radiation to have appropriate monitoring arrangements in place by this date to demonstrate that they can meet this new limit for all workers. Eye lens dose is conventionally monitored by specific dosemeters worn near the eye. However, it is usually impractical for these dosemeters to be worn at all times in the workplace which can lead to problems accounting for any periods of work when an eye lens dosemeter has not been worn...
November 20, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/29152838/commissioning-of-the-world-s-first-compact-pencil-beam-scanning-proton-therapy-system
#16
Rajesh Pidikiti, Bijal C Patel, Matthew R Maynard, Joseph P Dugas, Joseph Syh, Narayan Sahoo, Hsinshun Terry Wu, Lane R Rosen
This paper summarizes clinical commissioning of the world's first commercial, clinically utilized installation of a compact, image-guided, pencil-beam scanning, intensity-modulated proton therapy system, the IBA Proteus® ONE, at the Willis-Knighton Cancer Center (WKCC) in Shreveport, LA. The Proteus® ONE is a single-room, compact-gantry system employing a cyclotron-generated proton beam with image guidance via cone-beam CT as well as stereoscopic orthogonal and oblique planar kV imaging. Coupling 220° of gantry rotation with a 6D robotic couch capable of in plane patient rotations of over 180° degrees allows for 360° of treatment access...
January 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29140458/direct-measurements-of-skin-eye-lens-and-thyroid-dose-during-pediatric-brain-ct-examinations
#17
Agapi Ploussi, Ioannis Stathopoulos, Vasileios Syrgiamiotis, Triantafillia Makri, Christiana Hatzigiorgi, Kalliopi Platoni, Eleftheria Carinou, Efstathios P Efstathopoulos
Pediatric brain computed tomography (CT) is identified as the most frequent CT examination in children. The aim of the study is the direct measurement of skin, eye lens and thyroid dose in pediatric patients during brain CT examinations. The study included 35 pediatric patients who underwent brain CT examinations. The patients were categorized in three age groups: Group A (age range: 0.8-1 years), Group B (age range: 2.0-4.9 years) and Group C (age range: 5.5-15.5 years). thermoluminescent dosimeters (TLDs) were placed on the eyes, the frontal region of the head, the mastoid apophysis and the thyroid gland...
November 13, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29036685/nuclear-heating-in-lif-dosemeters-in-a-fusion-neutron-field-trial-of-direct-comparison-of-experimental-and-simulated-results
#18
Wladyslaw Pohorecki, Barbara Obryk
The results of nuclear heating measured by means of thermoluminescent dosemeters (TLD-LiF) in a Cu block irradiated by 14 MeV neutrons are presented. The integral Cu experiment relevant for verification of copper nuclear data at neutron energies characteristic for fusion facilities was performed in the ENEA FNG Laboratory at Frascati. Five types of TLDs were used: highly photon sensitive LiF:Mg,Cu,P (MCP-N), 7LiF:Mg,Cu,P (MCP-7) and standard, lower sensitivity LiF:Mg,Ti (MTS-N), 7LiF:Mg,Ti (MTS-7) and 6LiF:Mg,Ti (MTS-6)...
September 29, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28938858/evaluating-doses-of-multi-slice-ct-in-brain-examinations-using-various-methods
#19
Hung-Chih Lin, Te-Jen Lai, Hsien-Chun Tseng, Cheng-Hsun Lin, Yen-Ling Tseng, Chien-Yi Chen
PURPOSE: The effective dose (HE) and organ or tissue equivalent dose (HT) of a Rando phantom undergoing two brain computed tomography (CT) examination protocols were evaluated using thermoluminescent dosimeters (TLD-100H) and dose length product (DLP) methods. MATERIALS AND METHODS: TLDs were inserted into the correlated positions of an organ or tissue of Rando phantom, such as thyroid, brain, and salivary gland, using (A) axial scan: scanning the maxillae ranging from external auditory meatus to the parietal bone, and (B) helical scan: scanning from the mandible to the parietal bone...
September 22, 2017: Computer Assisted Surgery (Abingdon, England)
https://www.readbyqxmd.com/read/28915893/dosimetric-comparison-of-different-treatment-modalities-for-stereotactic-radiotherapy
#20
Shih-Ming Hsu, Yuan-Chun Lai, Chien-Chung Jeng, Chia-Ying Tseng
BACKGROUND: The modalities for performing stereotactic radiotherapy (SRT) on the brain include the cone-based linear accelerator (linac), the flattening filter-free (FFF) volumetric modulated arc therapy (VMAT) linac, and tomotherapy. In this study, the cone-based linac, FFF-VMAT linac, and tomotherapy modalities were evaluated by measuring the differences in doses delivered during brain SRT and experimentally assessing the accuracy of the output radiation doses through clinical measurements...
September 16, 2017: Radiation Oncology
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