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Radiation dose measurements

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https://www.readbyqxmd.com/read/28811997/estimation-of-kidneys-and-urinary-bladder-doses-based-on-the-region-of-interest-in-18-fluorine-fluorodeoxyglucose-positron-emission-tomography-computed-tomography-examination-a-preliminary-study
#1
Farida Aimi Mustapha, Farahnaz Ahmad Anwar Bashah, Ihsan M Yassin, Ahmad Saad Fathinul Fikri, Abdul Jalil Nordin, Hairil Rashmizal Abdul Razak
BACKGROUND: Kidneys and urinary bladder are common physiologic uptake sites of 18fluorine-fluorodeoxyglucose ((18)F-FDG) causing increased exposure of low energy ionizing radiation to these organs. Accurate measurement of organ dose is vital as (18)F-FDG is directly exposed to the organs. Organ dose from (18)F-FDG PET is calculated according to the injected (18)F-FDG activity with the application of dose coefficients established by International Commission on Radiological Protection (ICRP)...
June 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28811994/the-measurement-of-liver-fat-from-single-energy-quantitative-computed-tomography-scans
#2
Xiaoguang Cheng, Glen M Blake, J Keenan Brown, Zhe Guo, Jun Zhou, Fengzhe Wang, Liqiang Yang, Xiaohong Wang, Li Xu
BACKGROUND: Studies of soft tissue composition using computed tomography (CT) scans are often semi-quantitative and based on Hounsfield units (HU) measurements that have not been calibrated with a quantitative CT (QCT) phantom. We describe a study to establish the water (H2O) and dipotassium hydrogen phosphate (K2HPO4) basis set equivalent densities of fat and fat-free liver tissue. With this information liver fat can be accurately measured from any abdominal CT scan calibrated with a suitable phantom...
June 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28809759/independent-dose-verification-system-with-monte-carlo-simulations-using-topas-for-passive-scattering-proton-therapy-at-the-national-cancer-center-in-korea
#3
Wook-Geun Shin, Mauro Testa, Hak Soo Kim, Jong Hwi Jeong, Se Byeong Lee, Yeon-Joo Kim, Chul Hee Min
For the independent validation of treatment plans, we developed a Monte Carlo (MC)-based patient dose calculation system with the tool for particle simulation (TOPAS) to enable routine and automatic dose recalculation for each patient. The proton beam nozzle was modeled with TOPAS to simulate the therapeutic beam, and MC commissioning was performed by comparing percent depth dose with the measurement. The beam set-up based on the prescribed beam range and modulation width was automated by modifying the vendor-specific method...
August 15, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28809463/dose-escalated-radiation-therapy-is-associated-with-better-overall-survival-in-patients-with-bone-metastases-from-solid-tumors-a-propensity-score-matched-study
#4
Yung-Chih Chou, Chien-Yu Lin, Ping-Ching Pai, Chen-Kan Tseng, Cheng-En Hsieh, Kai-Ping Chang, Cheng-Lung Hsu, Chun-Ta Liao, Chun-Chieh Wang, Shy-Chyi Chin, Tzu-Chen Yen, Tsung-Ying Ho, Ji-Hong Hong, Kin-Fong Lei, Joseph Tung-Chieh Chang, Ngan-Ming Tsang
We aimed to compare the overall survival (OS) of patients with bone metastases (BM) from solid tumors after standard-dose radiotherapy ([RT]; 30 Gy administered in 10 fractions; EQD2Gy  = 32.5 Gy) and dose-escalated RT (EQD2Gy  > 32.5 Gy). We retrospectively reviewed the clinical charts of 1795 patients (median age, 62.3 years; age range, 18-96 years) with BM from solid tumors who were referred for RT to our institute between 2000 and 2013. These patients were assigned to the standard-dose (n = 1125; 63%) and dose-escalated (n = 670; 37%) RT groups...
August 15, 2017: Cancer Medicine
https://www.readbyqxmd.com/read/28808904/measurement-of-dose-in-radionuclide-therapy-by-using-cerenkov-radiation
#5
Yao Ai, Xiaobin Tang, Diyun Shu, Wencheng Shao, Chunhui Gong, Changran Geng, Xudong Zhang, Haiyan Yu
This work aims to determine the relationship between Cerenkov photon emission and radiation dose from internal radionuclide irradiation. Water and thyroid phantoms were used to simulate the distribution of Cerenkov photon emission and dose deposition through Monte Carlo method. The relationship between Cerenkov photon emission and dose deposition was quantitatively analyzed. A neck phantom was also used to verify Cerenkov photon detection for thyroid radionuclide therapy. Results show that Cerenkov photon emission and dose deposition exhibit the same distribution pattern in water phantom, and this relative distribution relationship also existed in the thyroid phantom...
August 14, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28807441/whole-body-dose-and-energy-measurements-in-radiotherapy-by-a-combination-of-lif-mg-cu-p-and-lif-mg-ti
#6
Pascal Hauri, Uwe Schneider
PURPOSE: Long-term survivors of cancer who were treated with radiotherapy are at risk of a radiation-induced tumor. Hence, it is important to model the out-of-field dose resulting from a cancer treatment. These models have to be verified with measurements, due to the small size, the high sensitivity to ionizing radiation and the tissue-equivalent composition, LiF thermoluminescence dosimeters (TLD) are well-suited for out-of-field dose measurements. However, the photon energy variation of the stray dose leads to systematic dose errors caused by the variation in response with radiation energy of the TLDs...
August 11, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28803974/influence-of-amylose-content-and-oxidation-level-of-potato-starch-on-acetylation-granule-structure-and-radicals-formation
#7
Sławomir Pietrzyk, Teresa Fortuna, Lesław Juszczak, Dorota Gałkowska, Małgorzata Bączkowicz, Maria Łabanowska, Magdalena Kurdziel
This study was aimed at determining the effect of the amylose content of starch and oxidation level of potato starch on the structure of starch granules, and susceptibility to chemical modification (acetylation) and subsequent generation of radicals. Potato starch and waxy potato starch were oxidised with sodium hypochlorite applied in doses corresponding to 10, 20, and 30gCl/kg starch, and then acetylated with acetic acid anhydride. The carboxyl, carbonyl, acetyl groups were determined in modified starches...
August 10, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28802976/prognostic-factors-associated-with-the-accuracy-of-deformable-image-registration-in-lung-cancer-patients-treated-with-stereotactic-body-radiotherapy
#8
Yasuharu Sugawara, Hidenobu Tachibana, Noriyuki Kadoya, Nozomi Kitamura, Amit Sawant, Keiichi Jingu
We evaluated the accuracy of an in-house program in lung stereotactic body radiation therapy (SBRT) cancer patients, and explored the prognostic factors associated with the accuracy of deformable image registrations (DIRs). The accuracy of the 3 programs which implement the free-form deformation and the B-spline algorithm was compared regarding the structures on 4-dimensional computed tomography (4DCT) image datasets between the peak-inhale and peak-exhale phases. The dice similarity coefficient (DSC) and normalized DSC (NDSC) were measured for the gross tumor volumes from 19 lung SBRT patients...
August 9, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28800299/representing-the-dosimetric-impact-of-deformable-image-registration-errors
#9
Jason Vickress, Jerry Battista, Rob Barnett, Slav Yartsev
Deformable image registration (DIR) is emerging as a tool in radiation therapy for calculating the cumulative dose distribution across multiple fractions of treatment. Unfortunately, due to the variable nature of DIR algorithms and dependence of performance on image quality, registration errors can result in dose accumulation errors. In this study, landmarked images were used to characterize the DIR error throughout an image space and determine its impact on dosimetric analysis. Ten thoracic 4DCT images with 300 landmarks per image study matching the end-inspiration and end-expiration phases were obtained from 'dir-labs'...
August 11, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28799263/characterization-of-a-novel-scale-maille-contralateral-breast-shield-smart-armor
#10
Macinley Butson, Susan Carroll, Martin Butson, Robin Hill
During breast radiotherapy treatment, the contralateral breast receives radiation doses to the skin and subcutaneous tissue caused mainly from incident electron contamination and low energy photon scatter radiation. Measurements have shown that for a typical hybrid tangential treatment, these dose levels can be up to 17% of maximum applied prescription dose if no shielding is used during the treatment process. This work examined the use of different shielding metals, aluminum, copper, and lead to reduce peripheral radiation dose to evaluate the optimal metal to form the basis of a contralateral breast radiation shield...
August 11, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28797451/post-operative-therapy-following-transoral-robotic-surgery-for-unknown-primary-cancers-of-the-head-and-neck
#11
Sapna A Patel, Aarthi Parvathaneni, Upendra Parvathaneni, Jeffrey J Houlton, Ron J Karni, Jay J Liao, Neal D Futran, Eduardo Méndez
OBJECTIVES: Our primary objective is to describe the post- operative management in patients with an unknown primary squamous cell carcinoma of the head and neck (HNSCC) treated with trans-oral robotic surgery (TORS). MATERIALS & METHODS: We conducted a retrospective multi-institutional case series including all patients diagnosed with an unknown primary HNSCC who underwent TORS to identify the primary site from January 1, 2010 to June 30, 2016. We excluded those with recurrent disease, ≤6months of follow up from TORS, previous history of radiation therapy (RT) to the head and neck, or evidence of primary tumor site based on previous biopsies...
September 2017: Oral Oncology
https://www.readbyqxmd.com/read/28796750/in-vivo-electron-paramagnetic-resonance-tooth-dosimetry-dependence-of-radiation-induced-signal-amplitude-on-the-enamel-thickness-and-surface-area-of-ex-vivo-human-teeth
#12
Michitaka Umakoshi, Ichiro Yamaguchi, Hiroshi Hirata, Naoki Kunugita, Benjamin B Williams, Harold M Swartz, Minoru Miyake
In vivo L-band electron paramagnetic resonance tooth dosimetry is a newly developed and very promising method for retrospective biodosimetry in individuals who may have been exposed to significant levels of ionizing radiation. The present study aimed to determine the relationships among enamel thickness, enamel area, and measured electron paramagnetic resonance signal amplitude with a view to improve the quantitative accuracy of the dosimetry technique. Ten isolated incisors were irradiated using well-characterized doses, and their radiation-induced electron paramagnetic resonance signals were measured...
August 7, 2017: Health Physics
https://www.readbyqxmd.com/read/28796645/on-the-use-of-particle-filters-for-electromagnetic-tracking-in-high-dose-rate-brachytherapy
#13
Theresa Ida Götz, Godehard Lahmer, Tobias Brandt, Karoline Kallis, Vratislav Strnad, Christoph Bert, Bernhard Hensel, Ana Maria Tome, Elmar W Lang
Modern radiotherapy of female breat cancers often employ high dose rate Brachytherapy, where a radioactive source is moved inside catheters, implanted in the female breast, according to a prescribed treatment plan. Source localization relative to the patient's anatomy is determined with solenoid sensors whose spatial positions are measured with an electromagnetic tracking system. Precise sensor dwell position determination is of utmost importance to assure irradiation of the cancerous tissue according to the treatment plan...
August 10, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28795419/simultaneous-mr-thermometry-and-acoustic-radiation-force-imaging-using-interleaved-acquisition
#14
Joshua T de Bever, Henrik Odéen, Lorne W Hofstetter, Dennis L Parker
PURPOSE: A novel and practical method for simultaneously performing MR acoustic radiation force imaging (ARFI) and proton resonance frequency (PRF)-shift thermometry has been developed and tested. This could be an important tool for evaluating the success of MR-guided focused ultrasound procedures for which MR-thermometry measures temperature and thermal dose and MR-ARFI detects changes in tissue mechanical properties. METHODS: MR imaging was performed using a gradient recalled echo segmented echo-planar imaging pulse sequence with bipolar motion encoding gradients (MEG)...
August 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28795076/intraoperative-radiation-exposure-during-hip-arthroscopy
#15
John P Salvo, Jake Zarah, Zaira S Chaudhry, Kirsten L Poehling-Monaghan
BACKGROUND: The frequency of hip arthroscopy for the treatment of acute and chronic chondrolabral pathology and femoroacetabular impingement (FAI) has increased exponentially over the past decade. While surgeon and patient radiation exposure has been well documented in other areas of the orthopaedic literature, little is known about the procedure-specific and cumulative doses affecting the hip arthroscopist. PURPOSE: To determine the mean annual radiation exposure to the hip arthroscopist and the mean surgeon exposure per case...
July 2017: Orthopaedic Journal of Sports Medicine
https://www.readbyqxmd.com/read/28792468/real-time-external-respiratory-motion-measuring-technique-using-an-rgb-d-camera-and-principal-component-analysis
#16
Udaya Wijenayake, Soon-Yong Park
Accurate tracking and modeling of internal and external respiratory motion in the thoracic and abdominal regions of a human body is a highly discussed topic in external beam radiotherapy treatment. Errors in target/normal tissue delineation and dose calculation and the increment of the healthy tissues being exposed to high radiation doses are some of the unsolicited problems caused due to inaccurate tracking of the respiratory motion. Many related works have been introduced for respiratory motion modeling, but a majority of them highly depend on radiography/fluoroscopy imaging, wearable markers or surgical node implanting techniques...
August 9, 2017: Sensors
https://www.readbyqxmd.com/read/28791026/decrease-of-markers-related-to-bone-erosion-in-serum-of-patients-with-musculoskeletal-disorders-after-serial-low-dose-radon-spa-therapy
#17
Aljona Cucu, Kateryna Shreder, Daniela Kraft, Paul Friedrich Rühle, Gerhart Klein, Gerhard Thiel, Benjamin Frey, Udo S Gaipl, Claudia Fournier
Musculoskeletal disorders (MSDs) are the most frequent cause of disability in Europe. Reduced mobility and quality of life of the patients are often associated with pain due to chronic inflammation. The inflammatory process, accompanied by a destruction of the cartilage and bone tissue, is discussed as a result of (A) the infiltration of immune cells into the joints, (B) an altered homeostasis of the joint cavity (synovium) with a critical role of bone remodeling cells, and (C) release of inflammatory factors including adipokines in the arthritic joint...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28780299/effect-of-protective-lead-curtains-on-scattered-radiation-exposure-to-the-operator-during-ureteroscopy-for-stone-disease-a-controlled-trial
#18
Takaaki Inoue, Atsushi Komemushi, Takashi Murota, Takashi Yoshida, Makoto Taguchi, Hidefumi Kinoshita, Tadashi Matsuda
OBJECTIVES: To evaluate a reduction in total radiation dose to the operator during ureteroscopy (URS) for stone disease by using protective lead curtains. METHODS: Two studies were planned to compare scattered radiation doses without (n-LC group) and with protective lead curtains (LC group). In study 1, we measured the spatial distribution of the scattered radiation dose using a human phantom simulating URS for stone management for both groups. In study 2, we prospectively randomized patients undergoing treatment for stone disease with URS into n-LC (n = 62) and LC group (n = 61)...
August 2, 2017: Urology
https://www.readbyqxmd.com/read/28778024/a-combination-of-radiation-and-the-hypoxia-activated-prodrug-evofosfamide-th-302-is-efficacious-against-a-human-orthotopic-pancreatic-tumor-model
#19
Carla Hajj, James Russell, Charles P Hart, Karyn A Goodman, Maeve A Lowery, Adriana Haimovitz-Friedman, Joseph O Deasy, John L Humm
This study was designed to investigate the effect of single-dose radiation therapy (RT) in combination with evofosfamide (TH-302), a hypoxia-activated prodrug, in a pre-clinical model of pancreatic cancer. AsPC1 tumors were implanted orthotopically in the pancreas of nude mice. Tumors were treated with 15 Gy of RT, using a 1 cm diameter field, and delivered as a continuous arc. Image-guidance to center the field on the tumor was based on CT imaging with intraperitoneal contrast. Evofosfamide (100 mg/kg, i.p...
July 21, 2017: Translational Oncology
https://www.readbyqxmd.com/read/28774760/dosimetric-comparison-of-rectal-sparing-capabilities-of-rectal-balloon-vs-injectable-spacer-gel-in-stereotactic-body-radiation-therapy-for-prostate-cancer-lessons-learned-from-prospective-trials
#20
Ryan T Jones, Nima Hassan Rezaeian, Neil B Desai, Yair Lotan, Xun Jia, Raquibul Hannan, D W Nathan Kim, Brad Hornberger, Jeffrey Dubas, Aaron M Laine, Michael J Zelefsky, Robert D Timmerman, Michael R Folkert
This study aimed to compare the rectal-sparing capabilities of rectal balloons vs absorbable injectable spacer gel in stereotactic body radiation therapy (SBRT) for prostate cancer. Patient samples included in this analysis were obtained from 2 multi-institutional prospective trials of SBRT for prostate cancer using a rectal balloon (n = 36 patients) and injectable spacer gel (n = 36). Treatment prescription dose was 45 Gy in 5 fractions in 42 patients; for equal comparison, the remaining 30 patients were rescaled to 45 Gy from 47...
July 31, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
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