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Sample records for evaluating radiation dose

  1. Evaluation of occupational and patient radiation doses in orthopedic surgery

    Energy Technology Data Exchange (ETDEWEB)

    Sulieman, A. [Salman bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P.O. Box 422, Alkharj (Saudi Arabia); Habiballah, B.; Abdelaziz, I. [Sudan Univesity of Science and Technology, College of Medical Radiologic Sciences, P.O. Box 1908, Khartoum (Sudan); Alzimami, K. [King Saud University, College of Applied Medical Sciences, Radiological Sciences Department, P.O. Box 10219, 11433 Riyadh (Saudi Arabia); Osman, H. [Taif University, College of Applied Medical Science, Radiology Department, Taif (Saudi Arabia); Omer, H. [University of Dammam, Faculty of Medicine, Dammam (Saudi Arabia); Sassi, S. A., E-mail: Abdelmoneim_a@yahoo.com [Prince Sultan Medical City, Department of Medical Physics, Riyadh (Saudi Arabia)

    2014-08-15

    Orthopedists are exposed to considerable radiation dose during orthopedic surgeries procedures. The staff is not well trained in radiation protection aspects and its related risks. In Sudan, regular monitoring services are not provided for all staff in radiology or interventional personnel. It is mandatory to measure staff and patient exposure in order to radiology departments. The main objectives of this study are: to measure the radiation dose to patients and staff during (i) Dynamic Hip Screw (Dhs) and (i i) Dynamic Cannula Screw (Dcs); to estimate the risk of the aforementioned procedures and to evaluate entrance surface dose (ESD) and organ dose to specific radiosensitive patients organs. The measurements were performed in Medical Corps Hospital, Sudan. The dose was measured for unprotected organs of staff and patient as well as scattering radiation. Calibrated Thermoluminescence dosimeters (TLD-Gr-200) of lithium fluoride (LiF:Mg, Cu,P) were used for ESD measurements. TLD signal are obtained using automatic TLD Reader model (Plc-3). The mean patients doses were 0.46 mGy and 0.07 for Dhs and Dcs procedures, respectively. The mean staff doses at the thyroid and chest were 4.69 mGy and 1.21 mGy per procedure. The mean radiation dose for staff was higher in Dhs compared to Dcs. This can be attributed to the long fluoroscopic exposures due to the complication of the procedures. Efforts should be made to reduce radiation exposure to orthopedic patients, and operating surgeons especially those with high work load. Staff training and regular monitoring will reduce the radiation dose for both patients and staff. (Author)

  2. Scalp Dose Evaluation According Radiation Therapy Technique of Whole Brain Radiation Therapy

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    Jang, Joon Yung; Park, Soo Yun; Kim, Jong Sik; Choi, Byeong Gi; Song, Gi Won [Dept. of Radiation Oncology, Samsung Medical Center, Seoul (Korea, Republic of)

    2011-09-15

    Opposing portal irradiation with helmet field shape that has been given to a patient with brain metastasis can cause excess dose in patient's scalp, resulting in hair loss. For this reason, this study is to quantitatively analyze scalp dose for effective prevention of hair loss by comparing opposing portal irradiation with scalp-shielding shape and tomotherapy designed to protect patient's scalp with conventional radiation therapy. Scalp dose was measured by using three therapies (HELMET, MLC, TOMO) after five thermo-luminescence dosimeters were positioned along center line of frontal lobe by using RANDO Phantom. Scalp dose and change in dose distribution were compared and analyzed with DVH after radiation therapy plan was made by using Radiation Treatment Planning System (Pinnacle3, Philips Medical System, USA) and 6 MV X-ray (Clinac 6EX, VARIAN, USA). When surface dose of scalp by using thermo-luminescence dosimeters was measured, it was revealed that scalp dose decreased by average 87.44% at each point in MLC technique and that scalp dose decreased by average 88.03% at each point in TOMO compared with HELMET field therapy. In addition, when percentage of volume (V95%, V100%, V105% of prescribed dose) was calculated by using Dose Volume Histogram (DVH) in order to evaluate the existence or nonexistence of hotspot in scalp as to three therapies (HELMET, MLC, TOMO), it was revealed that MLC technique and TOMO plan had good dose coverage and did not have hot spot. Reducing hair loss of a patient who receives whole brain radiotherapy treatment can make a contribution to improve life quality of the patient. It is expected that making good use of opposing portal irradiation with scalp-shielding shape and tomotherapy to protect scalp of a patient based on this study will reduce hair loss of a patient.

  3. Evaluation of radiation dose to patients in intraoral dental radiography using Monte Carlo Method

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    Park, Il; Kim, Kyeong Ho; Oh, Seung Chul; Song, Ji Young [Dept. of Nuclear Engineering, Kyung Hee University, Yongin (Korea, Republic of)

    2016-11-15

    The use of dental radiographic examinations is common although radiation dose resulting from the dental radiography is relatively small. Therefore, it is required to evaluate radiation dose from the dental radiography for radiation safety purpose. The objectives of the present study were to develop dosimetry method for intraoral dental radiography using a Monte Carlo method based radiation transport code and to calculate organ doses and effective doses of patients from different types of intraoral radiographies. Radiological properties of dental radiography equipment were characterized for the evaluation of patient radiation dose. The properties including x-ray energy spectrum were simulated using MCNP code. Organ doses and effective doses to patients were calculated by MCNP simulation with computational adult phantoms. At the typical equipment settings (60 kVp, 7 mA, and 0.12 sec), the entrance air kerma was 1.79 mGy and the measured half value layer was 1.82 mm. The half value layer calculated by MCNP simulation was well agreed with the measurement values. Effective doses from intraoral radiographies ranged from 1 μSv for maxilla premolar to 3 μSv for maxilla incisor. Oral cavity layer (23⁓82 μSv) and salivary glands (10⁓68 μSv) received relatively high radiation dose. Thyroid also received high radiation dose (3⁓47 μSv) for examinations. The developed dosimetry method and evaluated radiation doses in this study can be utilized for policy making, patient dose management, and development of low-dose equipment. In addition, this study can ultimately contribute to decrease radiation dose to patients for radiation safety.

  4. Technology Development for Radiation Dose Measurement and Evaluation

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    Kim, Bong Hwan; Chang, S. Y.; Lee, T. Y. (and others)

    2007-06-15

    The correction factors essential for the operation of In-Vivo counting system were produced and implemented into a field operation for the improvement of accuracy in measurement of the radioactivity inside a human body. The BiDAS2007 code which calculate an internal dose was developed by upgrading the former code prepared in the previous stage of this project. The method of using the multibioassy data, the maximum likelihood function and the Bayesian statistics were established to an internal dose based on the measurement data of radioactivity, intakes and retention of radioactivity in a human body and it can improve the accuracy in estimation of the intakes of radioactivity and the committed effective dose equivalent. In order to solve the problem of low detection efficiency of the conventional Bonner Sphere (BS) to a high energy neutron, the extended BS's were manufactured and the technique for neutron field spectrometry was established. The fast neutron and gamma spectrometry system with a BC501A scintillation detector was also prepared. Several neutron fluence spectra at several nuclear facilities were measured and collected by using the extended BS. The spectrum weighted responses of some neutron monitoring instruments were also derived by using these spectra and the detector response functions. A high efficient TL material for the neutron personal dosimeter was developed. It solved the main problem of low thermal stability and high residual dose of the commercial TLDs and has the sensitivity to neutron and to gamma radiation with 40 and 10 times higher respectively than them.

  5. Evaluation of dose equivalent rate distribution in JCO critical accident by radiation transport calculation

    CERN Document Server

    Sakamoto, Y

    2002-01-01

    In the prevention of nuclear disaster, there needs the information on the dose equivalent rate distribution inside and outside the site, and energy spectra. The three dimensional radiation transport calculation code is a useful tool for the site specific detailed analysis with the consideration of facility structures. It is important in the prediction of individual doses in the future countermeasure that the reliability of the evaluation methods of dose equivalent rate distribution and energy spectra by using of Monte Carlo radiation transport calculation code, and the factors which influence the dose equivalent rate distribution outside the site are confirmed. The reliability of radiation transport calculation code and the influence factors of dose equivalent rate distribution were examined through the analyses of critical accident at JCO's uranium processing plant occurred on September 30, 1999. The radiation transport calculations including the burn-up calculations were done by using of the structural info...

  6. Evaluation of radiation dose to anthropomorphic paediatric models from positron-emitting labelled tracers

    Science.gov (United States)

    Xie, Tianwu; Zaidi, Habib

    2014-03-01

    PET uses specific molecules labelled with positron-emitting radionuclides to provide valuable biochemical and physiological information. However, the administration of radiotracers to patients exposes them to low-dose ionizing radiation, which is a concern in the paediatric population since children are at a higher cancer risk from radiation exposure than adults. Therefore, radiation dosimety calculations for commonly used positron-emitting radiotracers in the paediatric population are highly desired. We evaluate the absorbed dose and effective dose for 19 positron-emitting labelled radiotracers in anthropomorphic paediatric models including the newborn, 1-, 5-, 10- and 15-year-old male and female. This is achieved using pre-calculated S-values of positron-emitting radionuclides of UF-NCI paediatric phantoms and published biokinetic data for various radiotracers. The influence of the type of anthropomorphic model, tissue weight factors and direct human- versus mouse-derived biokinetic data on the effective dose for paediatric phantoms was also evaluated. In the case of 18F-FDG, dosimetry calculations of reference paediatric patients from various dose regimens were also calculated. Among the considered radiotracers, 18F-FBPA and 15O-water resulted in the highest and lowest effective dose in the paediatric phantoms, respectively. The ICRP 103 updated tissue-weighting factors decrease the effective dose in most cases. Substantial differences of radiation dose were observed between direct human- versus mouse-derived biokinetic data. Moreover, the effect of using voxel- versus MIRD-type models on the calculation of the effective dose was also studied. The generated database of absorbed organ dose and effective dose for various positron-emitting labelled radiotracers using new generation computational models and the new ICRP tissue-weighting factors can be used for the assessment of radiation risks to paediatric patients in clinical practice. This work also contributes

  7. Evaluation of radiation dose for registered users of radioisotopes at Faculty of Engineering, Hiroshima University

    Energy Technology Data Exchange (ETDEWEB)

    Shizuma, Kiyoshi; Iwatani, Kazuo; Hasai, Hiromi (Hiroshima Univ., Higashi-Hiroshima (Japan). Faculty of Engineering)

    1993-12-01

    The effective dose equivalent for registered users of radioisotopes was evaluated. The external dose was evaluated from the dose measured with the film badge. The internal dose was evaluated on the basis of the concentration of radioisotopes in air, which is calculated beforehand for each facility. The radon concentration in air was measured for all facilities. The contribution of radon daughters to the internal dose was added for users of accelerator and electron microscope of radioactive samples. The maximum effective dose was 0.22 mSv among 97 users in 1992 and the dominant dose was 0.1-0.01 mSv. Present evaluation is important for individual radiation hazard control and also for fundamental data for abbreviation of health examination of users. (author).

  8. Evaluation of low dose ionizing radiation effect on some blood components in animal model

    OpenAIRE

    H. El-Shanshoury; G. El-Shanshoury; A. Abaza

    2016-01-01

    Exposure to ionizing radiation is known to have lethal effects in blood cells. It is predicted that an individual may spend days, weeks or even months in a radiation field without becoming alarmed. The study aimed to discuss the evaluation of low dose ionizing radiation (IR) effect on some blood components in animal model. Hematological parameters were determined for 110 animal rats (divided into 8 groups) pre- and post-irradiation. An attempt to explain the blood changes resulting from both ...

  9. Evaluation of radiation dose to neonates in a special care baby unit

    Science.gov (United States)

    Alzimami, K.; Sulieman, A.; Yousif, A.; Babikir, E.; Salih, I.

    2014-11-01

    The purpose of this study was to evaluate the patient entrance surface dose (ESD), organ dose and effective dose for neonates in the special care baby unit (SCBU) up to 28 days after birth. A total of 135 patients were examined during 4 months. ESDs were calculated from patient exposure parameters using DosCal software. Effective doses were calculated using software from the National Radiological Protection Board (NRPB). The mean patient ESD per procedure was 80±0.02 μGy. The mean and range of the effective dose per procedure were 0.02 (0.01-0.3) mSv. The radiation dose in this study was higher compared to previous studies. A dedicated X-ray machine with additional filtration is recommended for patient dose reductions.

  10. Evaluating Which Dose-Function Metrics Are Most Critical for Functional-Guided Radiation Therapy.

    Science.gov (United States)

    Faught, Austin M; Yamamoto, Tokihiro; Castillo, Richard; Castillo, Edward; Zhang, Jingjing; Miften, Moyed; Vinogradskiy, Yevgeniy

    2017-09-01

    Four-dimensional (4D) computed tomography (CT) ventilation imaging is increasingly being used to calculate lung ventilation and implement functional-guided radiation therapy in clinical trials. There has been little exhaustive work evaluating which dose-function metrics should be used for treatment planning and plan evaluation. The purpose of our study was to evaluate which dose-function metrics best predict for radiation pneumonitis (RP). Seventy lung cancer patients who underwent 4D CT imaging and pneumonitis grading were assessed. Pretreatment 4D CT scans of each patient were used to calculate ventilation images. We evaluated 3 types of dose-function metrics that combined the patient's 4D CT ventilation image and treatment planning dose distribution: (1) structure-based approaches; (2) image-based approaches using the dose-function histogram; and (3) nonlinear weighting schemes. Log-likelihood methods were used to generate normal tissue complication probability models predicting grade 3 or higher (ie, grade 3+) pneumonitis for all dose-function schemes. The area under the curve (AUC) was used to assess the predictive power of the models. All techniques were compared with normal tissue complication probability models based on traditional, total lung dose metrics. The most predictive models were structure-based approaches that focused on the volume of functional lung receiving ≥20 Gy (AUC, 0.70). Probabilities of grade 3+ RP of 20% and 10% correspond to V20 (percentage of volume receiving ≥20 Gy) to the functional subvolumes of 26.8% and 9.3%, respectively. Imaging-based analysis with the dose-function histogram and nonlinear weighted ventilation values yielded AUCs of 0.66 and 0.67, respectively, when we evaluated the percentage of functionality receiving ≥20 Gy. All dose-function metrics outperformed the traditional dose metrics (mean lung dose, AUC of 0.55). A full range of dose-function metrics and functional thresholds was examined. The

  11. The evaluation the magnitude radiation exposure dose rate in digital radiography room design

    Science.gov (United States)

    Dwiyanto, Agung; Setia Budi, Wahyu; Hardiman, Gagoek

    2017-12-01

    This study discusses the dose rate in digital radiography room, buit according to meet the provisions of KEMENKES No.1014 / Menkes / SK / XI / 2008 and Regulation of BAPETEN No. 8 / 2011. The provisions primary concern of radiation safety, not comfort, by considering the space design. There are five aspects to consider in designing the space: functionality, comfort, security, movement activities and aesthetics. However provisions only met three aspects of the design, which are a function, security and movement activity. Therefore, it is necessary to evaluate digital radiography room in terms of its ability to control external radiation exposure to be safe and comfortable The dose rate is measured by the range of primary and secondary radiation in the observation points by using Surveymeter. All data are obtained by the preliminary survey prior to the study. Furthermore, the review of digital radiography room is done based on architectural design theory. The dose rate for recommended improvement room is recalculated using the same method as the actual room with the help of computer modeling. The result of dose rate calculation at the inner and outer part of digital radiography observation room shows that in-room dose for a week at each measuring point exceeds the allowable dose limit both for staff and public. During a week of observation, the outdoor dose at some measuring points exceeds the dose limit set by the KEMENKES No.1014 / Menkes / SK / XI / 2008 and Regulation BEPETEN No 8/2011. Meanwhile, the result of dose rate calculation in the inner and outer part of the improved digital radiography room can meet the applicable regulations better.

  12. Does iterative reconstruction lower CT radiation dose: evaluation of 15,000 examinations.

    Directory of Open Access Journals (Sweden)

    Peter B Noël

    Full Text Available PURPOSE: Evaluation of 15,000 computed tomography (CT examinations to investigate if iterative reconstruction (IR reduces sustainably radiation exposure. METHOD AND MATERIALS: Information from 15,000 CT examinations was collected, including all aspects of the exams such as scan parameter, patient information, and reconstruction instructions. The examinations were acquired between January 2010 and December 2012, while after 15 months a first generation IR algorithm was installed. To collect the necessary information from PACS, RIS, MPPS and structured reports a Dose Monitoring System was developed. To harvest all possible information an optical character recognition system was integrated, for example to collect information from the screenshot CT-dose report. The tool transfers all data to a database for further processing such as the calculation of effective dose and organ doses. To evaluate if IR provides a sustainable dose reduction, the effective dose values were statistically analyzed with respect to protocol type, diagnostic indication, and patient population. RESULTS: IR has the potential to reduce radiation dose significantly. Before clinical introduction of IR the average effective dose was 10.1±7.8mSv and with IR 8.9±7.1mSv (p*=0.01. Especially in CTA, with the possibility to use kV reduction protocols, such as in aortic CTAs (before IR: average14.2±7.8mSv; median11.4mSv /with IR:average9.9±7.4mSv; median7.4mSv, or pulmonary CTAs (before IR: average9.7±6.2mSV; median7.7mSv /with IR: average6.4±4.7mSv; median4.8mSv the dose reduction effect is significant(p*=0.01. On the contrary for unenhanced low-dose scans of the cranial (for example sinuses the reduction is not significant (before IR:average6.6±5.8mSv; median3.9mSv/with IR:average6.0±3.1mSV; median3.2mSv. CONCLUSION: The dose aspect remains a priority in CT research. Iterative reconstruction algorithms reduce sustainably and significantly radiation dose in the clinical routine

  13. The evaluation of lens absorbed dose according to the optimold for whole brain radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yong Mo; Park, Byoung Suk; Ahn, Jong Ho; Song, Ki Won [Dept. of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2014-06-15

    In the current whole brain Radiation Therapy, Optimold was used to immobilize the head. However, skin dose was increased about 22% due to the scattering radiation by the Optimold. Since the minimum dose causing cataracts was 2 Gy, it could be seen that the effects were large especially on the lens. Therefore, in the whole brain Radiation Therapy, it was to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part. In order to compare and to evaluate the lens absorbed dose according to the presence of Optimold in the eyeball part, the Optimold mask was made up to 5 mm bolus on the part of the eye lens in the human model phantom (Anderson Rando Phantom, USA). In the practice treatment, to measure the lens dose, the simulation therapy was processed by placing the GafChromic EBT3 film under bolus, and after the treatment plan was set up through the treatment planning system (Pinnacle, PHILIPS, USA), the treatments were measured repeatedly three times in the same way. After removing the Optimold mask in the eyeball part, it was measured in the same way as above. After scanning the film and measuring the dose by using the Digital Flatbed Scanner (Expression 10000XL, EPSON, USA), the doses were compared and evaluated according to the presence of Optimold mask in the eyeball part. When there was the Optimold mask in the eyeball part, it was measured at 10.2cGy ± 1.5 in the simulation therapy, and at 24.8cGy ± 2.7 in the treatment, and when the Optimold mask was removed in the eye part, it was measured at 12.9cGy ± 2.2 in the simulation therapy, and at 17.6cGy ± 1.5 in the treatment. In case of removing the Optimold mask in the eyeball part, the dose was increased approximately 3cGy in the simulation therapy and was reduced approximately 7cGy in the treatment in comparison to the case that the Optimold mask was not removed. During the whole treatment, since the lens absorbed dose was reduced about 27%, the chance to cause

  14. Evaluation of the effect of low tube voltage on radiation dose and image quality

    Science.gov (United States)

    Norhasrina Nik Din, Nik; Zainon, Rafidah; Rahman, A. T. Abdul

    2017-05-01

    Number of Computed Tomography (CT) examinations performed worldwide is increasing. In 2010, the FDA issued an initiative to reduce unnecessary radiation exposure from CT imaging. The aim of this study is to evaluate the effect of low tube voltage on radiation dose and image quality using CTDI phantom. The CTDI phantom was scanned with dual energy CT at 80 kV and 120 kV with the tube current from 150 mAs to 350 mAs. Pitch was 1.0 while slice thickness was 1 mm and 5 mm. Results show if mAs was increased, the SNR values also will be increased. The 5 mm slice thickness shows higher SNR value compared to 1 mm slice thickness. As the voltage and tube current increased, the amount of dose absorbed is also increased because current is proportional to photon flux.

  15. Evaluation of patient radiation doses using DAP meter in interventional radiology procedures

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Byung Sam [Dept. of Radiological Technology. Shingu University, Sungnam (Korea, Republic of); Yoon, Yong Su [Dept. of Health Sciences, Graduate School of Medical Sciences, Kyushu Univeristy, Kyushu (Japan)

    2017-03-15

    The author investigated interventional radiology patient doses in several other countries, assessed accuracy of DAP meters embedded in intervention equipment in domestic country, conducted measurement of patient doses for 13 major interventional procedures with use of Dose Area Product(DAP) meters from 23 hospitals in Korea, and referred to 8,415 cases of domestic data related to interventional procedures by radiation exposure after evaluation the actual effective of dose reduction variables through phantom test. Finally, dose reference level for major interventional procedures was suggested. In this study, guidelines for patient doses were 237.7 Gy·cm{sup 2} in TACE, 17.3 Gy·cm{sup 2} in AVF, 114.1 Gy·cm{sup 2} in LE PTA and STENT, 188.5 Gy·cm{sup 2} in TFCA, 383.5 Gy·cm{sup 2} in Aneurysm Coil, 64.6 Gy·cm{sup 2} in PTBD, 64.6 Gy·cm{sup 2} in Biliary Stent, 22.4 Gy·cm{sup 2} in PCN, 4.3 Gy·cm{sup 2} in Hickman, 2.8 Gy·cm{sup 2} in Chemo-port, 4.4 Gy·cm{sup 2} in Perm-Cather, 17.1 Gy·cm{sup 2} in PCD, and 357.9 Gy·cm{sup 2} in Vis, EMB. Dose reference level acquired in this study is considered to be able to use as minimal guidelines for reducing patient dose in the interventional radiology procedures. For the changes and advances of materials and development of equipment and procedures in the interventional radiology procedures, further studies and monitoring are needed on dose reference level Korean DAP dose conversion factor for the domestic procedures.

  16. A practical tool to evaluate dose distributions using radiochromic film in radiation oncology.

    Science.gov (United States)

    Tamponi, M; Bona, R; Poggiu, A; Marini, P

    2015-02-01

    Triple channel algorithm and specific procedures make more reliable radiochromic dosimetry for treatment planning verification and quality assurance in radiation therapy. A tool to obtain radiochromic dose distributions and compare them with the ones resulting from a treatment planning system was developed and applied. The tool was developed as Microsoft Excel macro; it builds dose calibration curves against net optical density of Gafchromic EBT3 film, produces axial, coronal and sagittal dose maps and allows to evaluate them against dose distributions calculated by the Varian treatment planning system Eclipse using gamma index and gamma angle. The net optical density standard errors of estimate of calibration curves at 6 MV Varian DBX600 linac energy were 0.2%, 0.4% and 0.2% for the red, green and blue channels. Tests of these curves by means of three independent eight dose points measurement series, at 15 MV and 6 MV Varian 2100C linac and at 6 MV DBX600 linac energies, showed less than 2% of dose errors for the red channel and less than 3% for the green channel in the range 100-450 cGy. The comparisons between dose distributions from Gafchromic EBT3 triple channel algorithm and the ones from Eclipse analytic anisotropic algorithm (AAA) showed values of gamma index 95th percentile between 0.6 and 1.0. The obtained results encourage the application of this tool in radiation therapy quality assurance. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. Evaluation of the Entrance Surface Dose (ESD and Radiation Dose to the Radiosensitive Organs in Pediatric Pelvic Radiography

    Directory of Open Access Journals (Sweden)

    Vahid Karami

    2017-06-01

    Full Text Available Background Patients' dosimetry is crucial in order to enhance radiation protection optimization and to deliver low radiation dose to the patients in a radiological procedure. The aim of this study was to assess the entrance surface dose (ESD and radiation dose to the radiosensitive organs in pediatric pelvic radiography. Materials and Methods The studied population included 98 pediatric patients of both genders referred to anteroposterior (AP projection of pelvic radiography. The radiation dose was directly measured using high radiosensitive cylindrical lithium fluoride thermo-luminescent dosimeters (TLD-GR200. Two TLDs were placed at the center point of the radiation field to measure the ESD of pelvis. Moreover for each patient, 2 TLDs were placed upon each eyelid, 2 TLDs upon each breast, 2 TLDs upon the surface anatomical position of the thyroid gland and finally 2 TLDs at the surface anatomical position of the gonads to measure the received dose. Results The ESD ± standard deviation for AP pelvic radiography was obtained 591.7±76 µGy. Statistically significant difference was obtained between organs located outside and inside of the radiation field with respect to dose received (P

  18. Radiation dose evaluation during X-ray examinations in human medicine, dentistry, veterinary medicine and border controls using ionizing radiation; Dosisermittlung bei der Anwendung von Roentgenstrahlung in der medizinischen Heilkunde, zahnmedizinischen Heilkunde, Tierheilkunde und bei Grenzkontrollen mit ionisierender Strahlung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Ankerhold, U; Hupe, O. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    2012-02-15

    The report on radiation dose evaluation during X-ray examinations includes the following chapters: (1) Scope of the project. (2) Measuring instruments. (3) Part I: Radiation dose evaluation during X-ray examinations in human medicine, dentistry, veterinary medicine. (4) Radiation dose evaluation during X-ray examinations during border controls using ionizing radiation. (5) Summary of results.

  19. The use of equivalent radiation dose in the evaluation of late effects after childhood cancer treatment

    NARCIS (Netherlands)

    van Dijk, Irma W. E. M.; van Os, Rob M.; van de Kamer, Jeroen B.; Franken, Nicolaas A. P.; van der Pal, Helena J. H.; Koning, Caro C. E.; Caron, Huib N.; Ronckers, Cécile M.; Kremer, Leontien C. M.

    2014-01-01

    In epidemiologic research radiation-associated late effects after childhood cancer are usually analyzed without considering fraction dose. According to radiobiological principles, fraction dose is an important determinant of late effects. We aim to provide the rationale for using equivalent dose in

  20. Low-Radiation-Dose Modified Small Bowel CT for Evaluation of Recurrent Crohn's Disease

    Directory of Open Access Journals (Sweden)

    A. Z. Kielar

    2012-01-01

    Full Text Available Crohn's disease affects any part of the GI tract, commonly the terminal ileum. To decrease radiation exposure we developed a low-radiation-dose unenhanced CT (modified small Bowel CT, MBCT to evaluate the small bowel using hyperdense oral contrast. Technique. MBCT was investigated in patients with pathologically proven Crohn's disease presenting with new symptoms from recurrent inflammation or stricture. After ethics board approval, 98 consecutive patients were retrospectively evaluated. Kappa values from two independent reviewers were calculated for presence of obstruction, active inflammation versus chronic stricture, and ancillary findings. Forty-two patients underwent surgery or colonoscopy within 3 months. Results. Kappa was 0.84 for presence of abnormality versus a normal exam and 0.89 for differentiating active inflammation from chronic stricture. Level of agreement for presence of skip areas, abscess formation, and fistula was 0.62, 0.75, and 0.78, respectively. In the subset with “gold standard” follow-up, there was 83% agreement. Conclusions. MBCT is a low-radiation technique with good to very good interobserver agreement for determining presence of obstruction and degree of disease activity in patients with Crohn's disease. Further investigation is required to refine parameters of disease activity compared to CT enterography and small bowel follow through.

  1. Ultra-Low-Dose CT of the Thorax Using Iterative Reconstruction: Evaluation of Image Quality and Radiation Dose Reduction.

    Science.gov (United States)

    Kim, Yookyung; Kim, Yoon Kyung; Lee, Bo Eun; Lee, Seok Jeong; Ryu, Yon Ju; Lee, Jin Hwa; Chang, Jung Hyun

    2015-06-01

    The purpose of this study is to assess the image quality and radiation dose reduction of ultra-low-dose CT using sinogram-affirmed iterative reconstruction (SAFIRE). This prospective study enrolled 25 patients who underwent three consecutive unenhanced CT scans including low-dose CT (120 kVp and 30 mAs) and two ultra-low-dose CT protocols (protocol A, 100 kVp and 20 mAs; protocol B, 80 kVp and 30 mAs) with image reconstruction using SAFIRE. The image quality and radiation dose reduction were assessed. The mean (± SD) effective radiation dose was 1.06 ± 0.11, 0.44 ± 0.05, and 0.31 ± 0.03 mSv for low-dose CT, ultra-low-dose CT protocol A, and ultra-low-dose CT protocol B, respectively. Overall image quality was determined as diagnostic in 100% of low-dose CT scans, 96% of ultra-low-dose CT protocol A scans, and 88% of ultra-low-dose CT protocol B scans. All patients with nondiagnostic quality images had a body mass index (weight in kilograms divided by the square of height in meters) greater than 25. There was no statistically significant difference in detection frequencies of 14 lesion types among the three CT protocols, but pulmonary emphysema was detected in fewer patients (3/25) in ultra-low-dose CT protocol B scans compared with ultra-low-dose CT protocol A scans (5/25) or low-dose CT scans (6/25). We measured the longest dimensions of 33 small solid nodules (3.8-12.4 mm in long diameter) and found no statistically significant difference in the values afforded by the three CT protocols (p = 0.135). Iterative reconstruction allows ultra-low-dose CT and affords acceptable image quality, allowing size measurements of solid pulmonary nodules to be made.

  2. Evaluation of radiation doses in paediatric patients undergoing voiding cystourethrography; Avaliacao das doses de radiacao em uretrocistografia miccional de criancas

    Energy Technology Data Exchange (ETDEWEB)

    Travassos, Leonardo Vieira [Fundacao Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil). Instituto Fernandes Figueira; Boechat, Marcia Cristina Bastos; Santos, Eloa Nunez [Fundacao Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil). Instituto Fernandes Figueira. Servico de Radiologia; Santos, Eloa Nunez; Oliveira, Sergio Ricardo de; Silva, Marcos Otaviano da [Fundacao Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil); Carvalho, Antonio Carlos Pires [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Faculdade de Medicina. Dept . de Radiologia

    2009-01-15

    To evaluate dose-area product, skin entrance dose and doses from fluoroscopy and radiography in voiding cystourethrography studies of pediatric patients. Procedures performed in 37 patients by four physicians of the institution were evaluated. Measurements were performed with an equipment including an ionization chamber directly coupled to the x-ray tube window and an electrometer (Diamentor) connected to a computer for data collection. Some procedures heterogeneity was observed and guidelines for good radiographic techniques were not followed. On average, 11 radiographs are performed for each study, with extended fluoroscopy time delivering a higher average final dose than those reported in the literature. The adoption of radiography with high kilo voltage technique and restricted utilization of fluoroscopy can result in a significant reduction of doses during this procedure, considering that the major contribution to the final dose comes from fluoroscopy. (author)

  3. Doses from radiation exposure

    CERN Document Server

    Menzel, H G

    2012-01-01

    Practical implementation of the International Commission on Radiological Protection's (ICRP) system of protection requires the availability of appropriate methods and data. The work of Committee 2 is concerned with the development of reference data and methods for the assessment of internal and external radiation exposure of workers and members of the public. This involves the development of reference biokinetic and dosimetric models, reference anatomical models of the human body, and reference anatomical and physiological data. Following ICRP's 2007 Recommendations, Committee 2 has focused on the provision of new reference dose coefficients for external and internal exposure. As well as specifying changes to the radiation and tissue weighting factors used in the calculation of protection quantities, the 2007 Recommendations introduced the use of reference anatomical phantoms based on medical imaging data, requiring explicit sex averaging of male and female organ-equivalent doses in the calculation of effecti...

  4. Evaluation of an iterative model-based reconstruction of pediatric abdominal CT with regard to image quality and radiation dose.

    Science.gov (United States)

    Aurumskjöld, Marie-Louise; Söderberg, Marcus; Stålhammar, Fredrik; von Steyern, Kristina Vult; Tingberg, Anders; Ydström, Kristina

    2017-01-01

    Background In pediatric patients, computed tomography (CT) is important in the medical chain of diagnosing and monitoring various diseases. Because children are more radiosensitive than adults, they require minimal radiation exposure. One way to achieve this goal is to implement new technical solutions, like iterative reconstruction. Purpose To evaluate the potential of a new, iterative, model-based method for reconstructing (IMR) pediatric abdominal CT at a low radiation dose and determine whether it maintains or improves image quality, compared to the current reconstruction method. Material and Methods Forty pediatric patients underwent abdominal CT. Twenty patients were examined with the standard dose settings and 20 patients were examined with a 32% lower radiation dose. Images from the standard examination were reconstructed with a hybrid iterative reconstruction method (iDose(4)), and images from the low-dose examinations were reconstructed with both iDose(4) and IMR. Image quality was evaluated subjectively by three observers, according to modified EU image quality criteria, and evaluated objectively based on the noise observed in liver images. Results Visual grading characteristics analyses showed no difference in image quality between the standard dose examination reconstructed with iDose(4) and the low dose examination reconstructed with IMR. IMR showed lower image noise in the liver compared to iDose(4) images. Inter- and intra-observer variance was low: the intraclass coefficient was 0.66 (95% confidence interval = 0.60-0.71) for the three observers. Conclusion IMR provided image quality equivalent or superior to the standard iDose(4) method for evaluating pediatric abdominal CT, even with a 32% dose reduction.

  5. Knowledge-based iterative model reconstruction (IMR) algorithm in ultralow-dose CT for evaluation of urolithiasis: evaluation of radiation dose reduction, image quality, and diagnostic performance.

    Science.gov (United States)

    Park, Sung Bin; Kim, Yang Soo; Lee, Jong Beum; Park, Hyun Jeong

    2015-10-01

    To evaluate the efficacy of a knowledge-based iterative model reconstruction (IMR) algorithm for reducing image noise in ultralow-dose (ULD) CT for urolithiasis. A total of 103 patients diagnosed with urinary stones (n = 276) were enrolled. Regular dose (RD) scans (120 kV and 150 mAs, maximal tube current in dose modulation) were reconstructed using filtered back-projection (FBP, RD-FBP), and ULD scans (100 kV and 20 mAs, fixed tube current) were reconstructed with FBP (ULD-FBP), statistical iterative reconstruction (IR; ULD-iDose), and a knowledge-based IMR algorithm (ULD-IMR). Prospective interpretations of the two scans were performed with respect to radiation dose, objective image noise, and subjective assessment. The subjective assessment was also evaluated with regard to each patient's body mass index (BMI, < 25 or ≥ 25 kg/m(2)). Using RD CT (RD-FBP) as the reference standard, two reviewers assessed the diagnostic performance and inter-observer agreement for ULD-IMR. The average effective doses with RD CT and ULD CT were 8.31 and 0.68 mSv, respectively, and the average radiation dose reduction rate was 91.82% (p < 0.01). The lowest objective image noise was observed with ULD-IMR (p < 0.01). Subjective assessment in ULD-IMR was comparable to that of RD-FBP, although RD-FBP remained statistically superior. For BMI, there was a statistically significant difference in subjective image quality between the normal (4.7 ± 0.54) and overweight or obese groups (4.2 ± 0.5) (p < 0.05). The ULD-IMR showed a greater than 75% concordant rate in overall stones and 100% in ureter stones larger than 3 mm. However, for stones <3 mm, neither reviewer had a good detection rate (45.5% and 56.9% for the general and genitourinary radiologist, respectively). Inter-observer agreement was almost perfect (κ = 0.82). Despite a significant radiation dose reduction, ULD-IMR images were comparable in image quality and noise to RD-FBP images. Furthermore, the diagnostic performance of

  6. Low-radiation-dose dual-phase MDCT protocol with split contrast media dose and time optimization: protocol design for renal donors evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bazeed, Mohamed Fayez (Dept. of Diagnostic Radiology, Faculty of Medicine, Mansoura Univ. (Egypt)), email: bazeed@mans.eun.eg; Fooshang, Fawzy F (National Inst. of Urology and Nephrology (Egypt)); Ahmed, Magdy Aly (Nephrology Dept., Armed Forces Hospitals Southern Region (Saudi Arabia))

    2011-10-15

    Background A routine, multiphase, computed tomography (CT) protocol is associated with high radiation exposure to potential kidney donors. To reduce radiation exposure, several authors have suggested a reduction in the number of phases. Purpose To evaluate a low-radiation-dose, dual-phase protocol (i.e. a protocol with an unenhanced phase and combined vascular and excretory phase) for the preoperative evaluation of potential renal donors. Material and Methods Sixty-five potential renal donors were divided into two groups. The first group was scanned with a routine quadric-phase protocol (non-contrast, arterial, venous, and delayed), and the second group was scanned with a triple-phase protocol (dual phase protocol + venous phase). In the second group, we replaced CT angiography with a routine abdominal CT technique. In addition to the evaluation of renal arteries, veins, and excretory systems, the radiation dose of the suggested protocol was compared to that of the routine quadric-phase protocol. Results The suggested protocol was efficient in the evaluation of renal arteries, veins, and excretory systems in all studied potential renal donors. Renal arteries were well visualized in the combined vascular excretory phase using the routine abdominal CT technique; no significant difference was noted when these results were compared to those obtained from the CT angiography used in the quadric-phase protocol. The mean effective radiation dose of our suggested dual-phase protocol was only 34% of the dose resulting from the routine quadric-phase protocol. Conclusion Use of a low-radiation, dual-phase, CT protocol, which relied on both an unenhanced phase and a combined vascular and excretory phase, significantly reduced radiation dose. Furthermore, the proposed protocol provides adequate visualization of renal arteries and veins, and affords sufficient opacification of the urinary tract using improved acquisition triggering

  7. Evaluation of the radiation doses in newborn patients submitted to CT examinations

    Energy Technology Data Exchange (ETDEWEB)

    De Souza Santos, William; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares, Comissao Nacional de Energia Nuclear (IPENCNEN/SP), Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo, SP, (Brazil); Belinato, Walmir [Departamento de Ensino, Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia, Campus Vitoria da Conquista, Zabele, Av. Amazonas 3150, 45030-220 Vitoria da Conquista, BA, (Brazil); Pereira Neves, Lucio; Perini, Ana Paula [Instituto de Fisica, Universidade Federal de Uberlandia, Caixa Postal 593, 38400-902, Uberlandia, MG, (Brazil)

    2015-07-01

    The number of computed tomography (CT) scans available to the population is increasing, as well as the complexity of such exams. As a result, the radiation doses are increasing as well. Considering the population exposed to CT exams, pediatric patients are considerably more sensitive to radiation than adults. They have a longer life expectancy than adults, and may receive a higher radiation dose than necessary if the CT scan settings are not adjusted for their smaller body size. As a result of these considerations, the risk of developing cancer is of great concern when newborn patients are involved. The objective of this work was to study the radiation doses on radiosensitive organs of newborn patients undergoing a whole body CT examination, utilizing Monte Carlo simulations. The novelty of this work is the use of pediatric virtual anthropomorphic phantoms, developed at the Department of Nuclear Energy at the Federal University of Pernambuco (DEN/UFPE). The CT equipment utilized during the simulations was a Discovery VCT GE PET/CT system, with a tube voltage of 140 kVp. The X-ray spectrum of this CT scanner was generated by the SRS-78 software, which takes into account the X-ray beam energy used in PET/CT procedures. The absorbed organ doses were computed employing the F6 tally (MeV/g). The results were converted to dose coefficients (mGy/100 mA) for all the structures, considering all employed beams. The highest dose coefficients values were obtained for the brain and the thyroid. This work provides useful information regarding the risks involving ionizing radiation in newborn patients, employing a new and reliable technique. (authors)

  8. Evaluation of radiation dose to anthropomorphic paediatric models from positron-emitting labelled tracers

    NARCIS (Netherlands)

    Xie, Tianwu; Zaidi, Habib

    2014-01-01

    PET uses specific molecules labelled with positron-emitting radionuclides to provide valuable biochemical and physiological information. However, the administration of radiotracers to patients exposes them to low-dose ionizing radiation, which is a concern in the paediatric population since children

  9. Evaluation of low dose ionizing radiation effect on some blood components in animal model

    Directory of Open Access Journals (Sweden)

    H. El-Shanshoury

    2016-07-01

    The present findings suggest that damage from IR causes a significant reduction in blood cell counts in a dose-dependent manner, which may be considered a potential health risk during exposure to irradiation. Much effort must be done and focused on establishment of protocols for medical management of radiation injuries based on hematopoietic changes for biodosimetry.

  10. Individual radiation therapy patient whole-body phantoms for peripheral dose evaluations: method and specific software

    Energy Technology Data Exchange (ETDEWEB)

    Alziar, I; Vicente, C; Giordana, G; Ben-Harrath, O; De Vathaire, F; Diallo, I [U605 INSERM, Villejuif (France); Bonniaud, G; Couanet, D; Chavaudra, J; Lefkopoulos, D [Institut Gustave-Roussy, Villejuif (France); Ruaud, J B; Diaz, J C; Grandjean, P; Kafrouni, H [DOSIsoft, Cachan (France)], E-mail: ibrahim.diallo@igr.fr

    2009-09-07

    This study presents a method aimed at creating radiotherapy (RT) patient-adjustable whole-body phantoms to permit retrospective and prospective peripheral dose evaluations for enhanced patient radioprotection. Our strategy involves virtual whole-body patient models (WBPM) in different RT treatment positions for both genders and for different age groups. It includes a software tool designed to match the anatomy of the phantoms with the anatomy of the actual patients, based on the quality of patient data available. The procedure for adjusting a WBPM to patient morphology includes typical dimensions available in basic auxological tables for the French population. Adjustment is semi-automatic. Because of the complexity of the human anatomy, skilled personnel are required to validate changes made in the phantom anatomy. This research is part of a global project aimed at proposing appropriate methods and software tools capable of reconstituting the anatomy and dose evaluations in the entire body of RT patients in an adapted treatment planning system (TPS). The graphic user interface is that of a TPS adapted to obtain a comfortable working process. Such WBPM have been used to supplement patient therapy planning images, usually restricted to regions involved in treatment. Here we report, as an example, the case of a patient treated for prostate cancer whose therapy planning images were complemented by an anatomy model. Although present results are preliminary and our research is ongoing, they appear encouraging, since such patient-adjusted phantoms are crucial in the optimization of radiation protection of patients and for follow-up studies. (note)

  11. Evaluation of the space scattered dose according to the position of the radiation workers in mammography room

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Yeon [Dept. of Radiation Oncology, Dongnam Inst. of Radiological and Medical Science, Busan (Korea, Republic of); Lee, Jin Soo [Dept. of Radiology, Inje University Heaundae Paik Hospital, Busan (Korea, Republic of)

    2016-09-15

    This study was conducted to evaluate the dose of the space to the controller located within the mammography room conducted a research on ways to the reduction exposure to the radiation workers. Results, the dose of 6.18 mGy/year was measured when there is no difference in the hilar area of the controller position, the dose of 2.35E-11 mGy/year was measured when installing the Shielding door. In addition, when the direction of the X-ray tube anode be heading this direction controller, low average level measured was 0.30 mGy/year. Based on this study, the mammography should be considered when installing the anode and cathod directions. And, by installing the shielding door, it must be able to completely separate shooting space and control room. This is the best way radiation protection method in radiation workers.

  12. Evaluation of testicular dose and associated risk from common pelvis radiation therapy in Iran.

    Science.gov (United States)

    Shanei, Ahmad; Baradaran-Ghahfarokhi, Milad

    2014-12-01

    This study aimed to investigate testicular dose (TD) and the associated risk of heritable disease from common pelvis radiotherapy of male patients in Iran. In this work, the relation between TD and changes in beam energy, pelvis size, source to skin distance (SSD) and beam directions (anterior or posterior) was also evaluated. The values of TDs were measured on 67 randomly selected male patients during common pelvis radiotherapy using 1.17 and 1.33 MeV, Theratron Cobalt-60 unit at SSD of 80 cm and 9 MV, Neptun 10 PC and 18 MV, GE Saturne 20 at SSD of 100 cm at Seyed-Al Shohada Hospital, Isfahan, Iran. Results showed that, the maximum TD was up to 12% of the tumor dose. Considering the risk factor for radiation-induced heritable disorders of 0.1% per Sv, an excess risk of hereditary disorders of 72 per 10,000 births was conservatively calculated. There was a significant difference in the measured TD using different treatment machines and energies (P pelvis size (r = 0.275, P < 0.001). Using the student's t-tests, it was found that, there was not a significant difference between TD and beam direction (P = 0.231). Iranian male patients undergoing pelvic radiotherapy have the potential of receiving a TD of more than 1 Gy which might result in temporary azoospermia. The risk for induction of hereditary disorders in future generations should be considered as low but not negligible in comparison with the correspondent nominal risk. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  13. Radiation dose of nurses during IR procedures: a controlled trial evaluating operator alerts before nursing tasks.

    Science.gov (United States)

    Komemushi, Atsushi; Suzuki, Satoshi; Sano, Akira; Kanno, Shohei; Kariya, Shuji; Nakatani, Miyuki; Yoshida, Rie; Kono, Yumiko; Ikeda, Koshi; Utsunomiya, Keita; Harima, Yoko; Komemushi, Sadao; Tanigawa, Noboru

    2014-08-01

    To compare radiation exposure of nurses when performing nursing tasks associated with interventional procedures depending on whether or not the nurses called out to the operator before approaching the patient. In a prospective study, 93 interventional radiology procedures were randomly divided into a call group and a no-call group; there were 50 procedures in the call group and 43 procedures in the no-call group. Two monitoring badges were used to calculate effective dose of nurses. In the call group, the nurse first told the operator she was going to approach the patient each time she was about to do so. In the no-call group, the nurse did not say anything to the operator when she was about to approach the patient. In all the nursing tasks, the equivalent dose at the umbilical level inside the lead apron was below the detectable limit. The equivalent dose at the sternal level outside the lead apron was 0.16 μSv ± 0.41 per procedure in the call group and 0.51 μSv ± 1.17 per procedure in the no-call group. The effective dose was 0.018 μSv ± 0.04 per procedure in the call group and 0.056 μSv ± 0.129 per procedure in the no-call group. The call group had a significantly lower radiation dose (P = .034). Radiation doses of nurses were lower in the group in which the nurse called to the operator before she approached the patient. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

  14. A mouse model of cytogenetic analysis to evaluate caesium137 radiation dose exposure and contamination level in lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Roch-Lefevre, Sandrine; Martin-Bodiot, Cecile; Gregoire, Eric; Roy, Laurence [Institut de Radioprotection et de Surete Nucleaire (IRSN), Laboratoire de Dosimetrie Biologique (PRP-HOM/SRBE/LDB), Fontenay aux Roses Cedex (France); Desbree, Aurelie [Institut de Radioprotection et de Surete Nucleaire (IRSN), PRP-HOM/SDI, Laboratoire d' Evaluation de la Dose Interne, Fontenay aux Roses Cedex (France); Barquinero, Joan Francesc [Institut de Radioprotection et de Surete Nucleaire (IRSN), Laboratoire de Dosimetrie Biologique (PRP-HOM/SRBE/LDB), Fontenay aux Roses Cedex (France); Universitat Autonoma de Barcelona, Unitat d' Antropologia Biologica, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Bellaterra (Spain)

    2016-03-15

    In case of external overexposure to ionizing radiation, an estimation of its genotoxic effects on exposed individuals can be made retrospectively by the measurement of radiation-induced chromosome aberrations on circulating lymphocytes. Compared with external irradiation, intakes of radionuclides may, however, lead to specific features influencing dose distribution at the scale of body, of tissue or even of cell. Therefore, in case of internal contamination by radionuclides, experimental studies, particularly using animal models, are required to better understand mechanisms of their genotoxic effects and to better estimate the absorbed dose. The present study was designed to evaluate a cytogenetic method in mouse peripheral blood lymphocytes that would allow determination of yields and complexities of chromosome aberrations after low-dose rate exposure to {sup 137}Cs delivered in vitro either by irradiation or by contamination. By using M-FISH analysis, we compared the low-dose rate responses observed in mouse to the high-dose rate responses observed both in mouse and in human. Promising similarities between the two species in the relative biological effect evaluation show that our cytogenetic model established in mouse might be useful to evaluate various radiation exposures, particularly relevant in case of intakes of radionuclides. (orig.)

  15. Evaluation of Radiation Dose Exposure for Silicon Pixel Detectors in ALICE Experiment

    CERN Document Server

    Morando, M; CERN. Geneva

    1996-01-01

    An estimation of radiation dose exposure expected for the Inner Tracking System (ITS) of ALICE experiment at the future LHC collider is presented. In particular, the two innermost layers of the silicon ITS, located at radial distances of 3.9 and 7.6cm are based on hybrid silicon pixel detectors. A possible scenario for the first ten years operation is presented assuming a data taking with beams of lead, calcium and proton.

  16. Impact of adaptive statistical iterative reconstruction on radiation dose in evaluation of trauma patients

    Science.gov (United States)

    Maxfield, Mark W.; Schuster, Kevin M.; McGillicuddy, Edward A.; Young, Calvin J.; Ghita, Monica; Bokhari, S.A. Jamal; Oliva, Isabel B.; Brink, James A.; Davis, Kimberly A.

    2013-01-01

    BACKGROUND A recent study showed that computed tomographic (CT) scans contributed 93% of radiation exposure of 177 patients admitted to our Level I trauma center. Adaptive statistical iterative reconstruction (ASIR) is an algorithm that reduces the noise level in reconstructed images and therefore allows the use of less ionizing radiation during CT scans without significantly affecting image quality. ASIR was instituted on all CT scans performed on trauma patients in June 2009. Our objective was to determine if implementation of ASIR reduced radiation dose without compromising patient outcomes. METHODS We identified 300 patients activating the trauma system before and after the implementation of ASIR imaging. After applying inclusion criteria, 245 charts were reviewed. Baseline demographics, presenting characteristics, number of delayed diagnoses, and missed injuries were recorded. The postexamination volume CT dose index (CTDIvol) and dose-length product (DLP)reported by the scanner for CT scans of the chest, abdomen, and pelvis and CT scans of the brain and cervical spine were recorded. Subjective image quality was compared between the two groups. RESULTS For CT scans of the chest, abdomen, and pelvis, the mean CTDIvol(17.1 mGy vs. 14.2 mGy; p ASIR. For CT scans of the brain and cervical spine, the mean CTDIvol(61.7 mGy vs. 49.6 mGy; p ASIR. There was no subjective difference in image quality between ASIR and non-ASIR scans. All CT scans were deemed of good or excellent image quality. There were no delayed diagnoses or missed injuries related to CT scanning identified in either group. CONCLUSION Implementation of ASIR imaging for CT scans performed on trauma patients led to a nearly 20% reduction in ionizing radiation without compromising outcomes or image quality. PMID:23147183

  17. Evaluation of radiation dose during the percutaneous angioplasty for arteriovenous shunt assembling

    Science.gov (United States)

    Ting, Chien-Yi; Wu, Wen-Shiann; Tang, Kuo-Ting; Wang, Hsin-Ell; Lin, Chun-Chih

    2017-11-01

    Percutaneous angioplasty (PTA) for dysfunctional hemodialysis is usually performed by radiologists, but not cardiologists, in Taiwan, so that the radiation dose in patients and physicians are usually unknown and related studies are rare. In this study, we are pioneering an investigation into the radiation dose in percutaneous angioplasty for arteriovenous shunt assembling and the effect of RADPAD device, a lead-free surgical drape containing Bi and Ba, on the decrease of a radiation dose in the non-targeted organs of the patient and also the operator. The radiation dose in a typical digital subtraction angiography (DSA) by the PTA protocol under a fixed field of view (FOV), was measured with optically simulated luminescent dosimeters arranged in a PIXY RS-102 anthropomorphic phantom. The results indicate that there is a significant dose reduction at the hands (0.022±0.002 mGy before treatment vs. 0.014±0.001 mGy after treatment; P=0.021), but not at the lens (0.027±0.003 mGy before treatment vs. 0.018±0.001 mGy after treatment; P=0.058), and the gonads (0.026±0.003 mGy before treatment vs. 0.020±0.001 mGy after treatment; P=0.058), of the cardiologist/operator after treatment with the RADPAD drape. At the patient's abdomen, the dose significantly decreased from 1.597±0.104 mGy to 0.031±0.002 mGy (P<0.001) after treated with the RADPAD shield. For the chest, lens and thyroid in the patient, the doses were respectively 0.154±0.100 mGy (compared to 0.049±0.001 mGy after treated with the RADPAD drape; P=0.0002), 0.066±0.001 mGy (compared to 0.021±0.001 mGy after the RADPAD treatment; P=0.009), and 0.208±0.002 mGy (compared to 0.042±0.003 mGy after shielded with the RADPAD drape; P<0.0001), which represents an apparent reduction in dose. However, no significant difference was found in the dose-area product between before (179.9±0.1mGy.cm2) and after (177.4±0.1mGy.cm2) the treatment (P=0.38). In conclusion, the RADPAD drape significantly reduced radiation

  18. Charpak, Garwin, propose unit for radiation dose

    CERN Multimedia

    Feder, Toni

    2002-01-01

    Becquerels, curries, grays, rads, rems, roentgens, sieverts - even for specialists the units of radiation can get confusing. That's why two eminent physicists, Georges Charpak of France, and Richard Garwin, are proposing the DARI as a unit of radiation dose they hope will help the public evaluate the risks associated with low-level radiation exposure (1 page)

  19. [Evaluation of Radiation Dose during Stent-graft Treatment Using a Hybrid Operating Room System].

    Science.gov (United States)

    Haga, Yoshihiro; Chida, Kouichi; Kaga, Yuji; Saitou, Kazuhisa; Arai, Takeshi; Suzuki, Shinichi; Iwaya, Yoshimi; Kumasaka, Eriko; Kataoka, Nozomi; Satou, Naoto; Abe, Mitsuya

    2015-12-01

    In recent years, aortic aneurysm treatment with stent graft grafting in the X-ray fluoroscopy is increasing. This is an endovascular therapy, because it is a treatment which includes the risk of radiation damage, having to deal with radiation damage, to know in advance is important. In this study, in order to grasp the trend of exposure stent graft implantation in a hybrid operating room (OR) system, focusing on clinical data (entrance skin dose and fluoroscopy time), was to count the total. In TEVAR and EVAR, fluoroscopy time became 13.40 ± 7.27 minutes, 23.67 ± 11.76 minutes, ESD became 0.87 ± 0.41 mGy, 1.11 ± 0.57 mGy. (fluoroscopy time of EVAR was 2.0 times than TEVAR. DAP of EVAR was 1.2 times than TEVAR.) When using the device, adapted lesions and usage are different. This means that care changes in exposure-related factors. In this study, exposure trends of the stent graft implantation was able to grasp. It can be a helpful way to reduce/optimize the radiation dose in a hybrid OR system.

  20. Evaluation of the impact of a system for real-time visualisation of occupational radiation dose rate during fluoroscopically guided procedures.

    Science.gov (United States)

    Sandblom, V; Mai, T; Almén, A; Rystedt, H; Cederblad, Å; Båth, M; Lundh, C

    2013-09-01

    Optimisation of radiological protection for operators working with fluoroscopically guided procedures has to be performed during the procedure, under varying and difficult conditions. The aim of the present study was to evaluate the impact of a system for real-time visualisation of radiation dose rate on optimisation of occupational radiological protection in fluoroscopically guided procedures. Individual radiation dose measurements, using a system for real-time visualisation, were performed in a cardiology laboratory for three cardiologists and ten assisting nurses. Radiation doses collected when the radiation dose rates were not displayed to the staff were compared to radiation doses collected when the radiation dose rates were displayed. When the radiation dose rates were displayed to the staff, one cardiologist and the assisting nurses (as a group) significantly reduced their personal radiation doses. The median radiation dose (Hp(10)) per procedure decreased from 68 to 28 μSv (p = 0.003) for this cardiologist and from 4.3 to 2.5 μSv (p = 0.001) for the assisting nurses. The results of the present study indicate that a system for real-time visualisation of radiation dose rate may have a positive impact on optimisation of occupational radiological protection. In particular, this may affect the behaviour of staff members practising inadequate personal radiological protection.

  1. Comparative study of DTS and CT in the skeletal trauma imaging diagnosis evaluation and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Wei, E-mail: gangqiaxia@163.com [Clinical Medical College, Yangzhou University, Subei People' s Hospital of Jiangsu Province, Yangzhou 225001 (China); Yin, Xiao-rui; Wu, Jing-Tao; Wu, Hai-tao [Clinical Medical College, Yangzhou University, Subei People' s Hospital of Jiangsu Province, Yangzhou 225001 (China)

    2013-02-15

    Purpose: To compare the differences between CT (Computed tomography) and DTS (digital tomosynthesis) in the X-ray radiation dose, and to analyze the sensitivity and specificity of each examination to check the suspected fractures and dislocations cases. Methods: From May 2010 to February 2012, 46 patients suspected with fractures and/or dislocations were prospectively enrolled to do the CT and DTS examination on the basis of the results of DR examination. Patients were considered ineligible if they were pregnant or lactating (female subjects only). The Yangzhou Regional Ethical Review Board in Jiangsu province, China approved this study. All 46 patients signed the informed consent. To contrast radiation dose between CT and DTS group of the patients and make statistical analysis. Two experienced experts assess the image quality by I–III grade and make statistical analysis. Draw the ROC of reader A and B according to the golden standard of clinical diagnosis. Results: The average effective dose of CT Group is 5.46 msv, while average effective dose of DTS group is 0.07 msv.There is significant statistical difference (t = 22.89, p < 0.01) between them. Calculate and compare the area under the ROC curve of reader A and B. The area of reader A by CT and DTS is 0.999 ± 0.005, 0.973 ± 0.022. The area of reader B is 0.961 ± 0.026, 0.944 ± 0.032. Both of them perform z test, and P > 0.05. There is no significant difference. Assess the uniformity of two readers with Kappa test. The Kappa value of reader A and B is respectively 0.757 and 0.783. When the value is greater than 0.75, two readers’ uniformity is considered well. The two readers’ sensitivity and specificity in diagnosing hidden skeletal trauma with CT and DTS are respectively 97.06% (reader A), 96.97% (reader B); 91.67% (reader A), 84.62% (reader B). Use the χ{sup 2} test to them, then get the same result: P > 0.05. There is no statistical significant. Conclusion: Radiation dose of VolumnRAD DTS only

  2. Evaluation of dose distribution for targets near inhomogeneities in photon beam radiation therapy

    Science.gov (United States)

    Spirydovich, Siarhei

    Purpose. The purpose of this work was to evaluate the accuracy of the dose calculated in the presence of inhomogeneities by the top performing algorithms employed by some commercially available modern treatment planning systems for the external photon beam radiotherapy. Materials and methods. A new Fluence Map Monte Carlo (FMMC) method that can serve as a benchmark for such evaluation under certain conditions for a given linear accelerator was developed and tested. Dose perturbation on the inhomogeneities composed of high, low and very low density materials was measured with film dosimeters and calculated with various algorithms. The algorithms included general purpose Monte Carlo and FMMC methods as well as the treatment planning dose calculation algorithms such as pencil beam kernel convolution, point kernel convolution, and superposition, which is the most accurate of the three. Results. The dosimetric comparison results for high density materials obtained by FMMC, superposition, and measurement revealed that the superposition overestimates (up to 16%) of the dose downstream of the inhomogeneity. A very low density medium such as an air cavity was found to have an overestimation (up to 20%) of the dose by the superposition algorithm. The dose in a lung (low density medium) equivalent material was found to be significantly overestimated when calculated with either point kernel (up to 20%) or pencil beam kernel (up to 40%) convolution algorithms. Conclusion. Based on these findings it is recommended that a particular attention should be given to the verification of a dose calculated for the treatment of tumors located in anatomical sites where inhomogeneities are predominant. In many cases a verification process can be successfully performed with the proposed FMMC method which is shown to have a good match with the measurements.

  3. Dose-response relationship of octylphenol and radiation evaluated by tradescantia-micronucleus assay

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. K.; Cheon, K. J.; Lee, B. H. [KAERI, Taejon (Korea, Republic of); Shin, H. S.; Lee, J. H. [Chungnam National Univ., Taejon (Korea, Republic of)

    2002-05-01

    Many kinds of synthetic chemicals have been being used for various purposes. Some of them are called 'Endocrine Disruptor's because they can disturb the endocrine system of organisms. Presently no technique is established for the quantitative assessment of biological risk of the environmental hormones. The pollen mother cells (PMC) of Tradescantia are very sensitive to chemical toxicants or ionizing radiation, and thus can be used as a biological end-point assessing their effect. Micronucleus frequencies in PMC showed a good dose- and concentration-response relationship for radiation, bisphenol A and octylphenol. A parallel series of experiment using five increasing doses of gamma-ray at 10, 20, 30, 40 and 50 cGy was conducted. The MCN frequencies of 12.0, 25.2, 41.7, 76 and 83 MCN/100 tetrads were observed from each of the increasing gamma-ray dosage groups, respectively. Lenear regression analysis of the gamma-ray data MCN frequencies yielded a correlation coefficient of 0.95. the MCN frequencies in pollen mother cells treated with bisphenol a and octylphenol showed dose-response relationship in a concentration of 0, 1, 2, 4 {mu}M and 0, 4, 10, 20 {mu}M. the MCN frequency for the bisphenol a and octylphenol group yields 2.33, 8.06, 12.7 and 19.6 MCN/100 tetrads for the bisphenol a and 2.33, 2.33, 11.47, 17.6 MCN/100 tetrads for the octylphenol. The MCN frequency of the control was 2.33 MCN/100 tetrads. It is known from the result that Trad-MCN assay can be an excellent tool for detection of biological risk due to environmental toxicants or synthetic chemicals.

  4. Performance evaluation of iterative reconstruction algorithms for achieving CT radiation dose reduction - a phantom study.

    Science.gov (United States)

    Dodge, Cristina T; Tamm, Eric P; Cody, Dianna D; Liu, Xinming; Jensen, Corey T; Wei, Wei; Kundra, Vikas; Rong, X John

    2016-03-08

    The purpose of this study was to characterize image quality and dose performance with GE CT iterative reconstruction techniques, adaptive statistical iterative recontruction (ASiR), and model-based iterative reconstruction (MBIR), over a range of typical to low-dose intervals using the Catphan 600 and the anthropomorphic Kyoto Kagaku abdomen phantoms. The scope of the project was to quantitatively describe the advantages and limitations of these approaches. The Catphan 600 phantom, supplemented with a fat-equivalent oval ring, was scanned using a GE Discovery HD750 scanner at 120 kVp, 0.8 s rotation time, and pitch factors of 0.516, 0.984, and 1.375. The mA was selected for each pitch factor to achieve CTDIvol values of 24, 18, 12, 6, 3, 2, and 1 mGy. Images were reconstructed at 2.5 mm thickness with filtered back-projection (FBP); 20%, 40%, and 70% ASiR; and MBIR. The potential for dose reduction and low-contrast detectability were evaluated from noise and contrast-to-noise ratio (CNR) measurements in the CTP 404 module of the Catphan. Hounsfield units (HUs) of several materials were evaluated from the cylinder inserts in the CTP 404 module, and the modulation transfer function (MTF) was calculated from the air insert. The results were con-firmed in the anthropomorphic Kyoto Kagaku abdomen phantom at 6, 3, 2, and 1mGy. MBIR reduced noise levels five-fold and increased CNR by a factor of five compared to FBP below 6mGy CTDIvol, resulting in a substantial improvement in image quality. Compared to ASiR and FBP, HU in images reconstructed with MBIR were consistently lower, and this discrepancy was reversed by higher pitch factors in some materials. MBIR improved the conspicuity of the high-contrast spatial resolution bar pattern, and MTF quantification confirmed the superior spatial resolution performance of MBIR versus FBP and ASiR at higher dose levels. While ASiR and FBP were relatively insensitive to changes in dose and pitch, the spatial resolution for MBIR

  5. An FMEA evaluation of intensity modulated radiation therapy dose delivery failures at tolerance criteria levels.

    Science.gov (United States)

    Faught, Jacqueline Tonigan; Balter, Peter A; Johnson, Jennifer L; Kry, Stephen F; Court, Laurence E; Stingo, Francesco C; Followill, David S

    2017-11-01

    The objective of this work was to assess both the perception of failure modes in Intensity Modulated Radiation Therapy (IMRT) when the linac is operated at the edge of tolerances given in AAPM TG-40 (Kutcher et al.) and TG-142 (Klein et al.) as well as the application of FMEA to this specific section of the IMRT process. An online survey was distributed to approximately 2000 physicists worldwide that participate in quality services provided by the Imaging and Radiation Oncology Core - Houston (IROC-H). The survey briefly described eleven different failure modes covered by basic quality assurance in step-and-shoot IMRT at or near TG-40 (Kutcher et al.) and TG-142 (Klein et al.) tolerance criteria levels. Respondents were asked to estimate the worst case scenario percent dose error that could be caused by each of these failure modes in a head and neck patient as well as the FMEA scores: Occurrence, Detectability, and Severity. Risk probability number (RPN) scores were calculated as the product of these scores. Demographic data were also collected. A total of 181 individual and three group responses were submitted. 84% were from North America. Most (76%) individual respondents performed at least 80% clinical work and 92% were nationally certified. Respondent medical physics experience ranged from 2.5 to 45 yr (average 18 yr). A total of 52% of individual respondents were at least somewhat familiar with FMEA, while 17% were not familiar. Several IMRT techniques, treatment planning systems, and linear accelerator manufacturers were represented. All failure modes received widely varying scores ranging from 1 to 10 for occurrence, at least 1-9 for detectability, and at least 1-7 for severity. Ranking failure modes by RPN scores also resulted in large variability, with each failure mode being ranked both most risky (1st) and least risky (11th) by different respondents. On average MLC modeling had the highest RPN scores. Individual estimated percent dose errors and severity

  6. Radiation dose evaluation in patients submitted to conventional radiological examinations; Avaliacoes de doses de radiacao em pacientes submetidos a exames radiologicos convencionais

    Energy Technology Data Exchange (ETDEWEB)

    Tilly Junior, Joao G

    1997-07-01

    This work presents the results of the evaluation of radiation dose delivered to the patients undergoing conventional radiological procedures. Based in the realized measurement some indicators are settled to quantitative appraisal of the radiological protection conditions offered to the population. Data assessment was done in the county of Curitiba, in Parana State, Brazil, from 12/95 to 04/96, in ten rooms of three different institutions, under 101 patients, adults with 70 {+-} 10 kg, during real examinations of chest PA, chest LAT and abdomen AP. (author)

  7. Radiation dose estimates for radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Stabin, M.G.; Stubbs, J.B.; Toohey, R.E. [Oak Ridge Inst. of Science and Education, TN (United States). Radiation Internal Dose Information Center

    1996-04-01

    Tables of radiation dose estimates based on the Cristy-Eckerman adult male phantom are provided for a number of radiopharmaceuticals commonly used in nuclear medicine. Radiation dose estimates are listed for all major source organs, and several other organs of interest. The dose estimates were calculated using the MIRD Technique as implemented in the MIRDOSE3 computer code, developed by the Oak Ridge Institute for Science and Education, Radiation Internal Dose Information Center. In this code, residence times for source organs are used with decay data from the MIRD Radionuclide Data and Decay Schemes to produce estimates of radiation dose to organs of standardized phantoms representing individuals of different ages. The adult male phantom of the Cristy-Eckerman phantom series is different from the MIRD 5, or Reference Man phantom in several aspects, the most important of which is the difference in the masses and absorbed fractions for the active (red) marrow. The absorbed fractions for flow energy photons striking the marrow are also different. Other minor differences exist, but are not likely to significantly affect dose estimates calculated with the two phantoms. Assumptions which support each of the dose estimates appears at the bottom of the table of estimates for a given radiopharmaceutical. In most cases, the model kinetics or organ residence times are explicitly given. The results presented here can easily be extended to include other radiopharmaceuticals or phantoms.

  8. SU-F-P-26: Study of Radiation Dose Evaluation for Organs at Risk Using MRI in Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Gong, G; Guo, Y; Yin, Y [Shandong Cancer Hospital and Institute, Jinan, Shandong (China)

    2016-06-15

    Purpose: To study the contour and dosimetric feature of organs at risk (OARs) applying magnetic resonance imaging (MRI) images in intensity modulated radiation therapy (IMRT) of nasopharyngeal carcinoma (NPC) compared to computed tomography (CT) images. Methods: 35 NPC patients was selected into this trail. CT simulation with non-contrast and contrast enhanced scan, MRI simulation with non-contrast and contrast enhanced T1, T2 and diffusion weighted imaging were achieved sequentially. And the OARs were contoured on the CT and MRI images after rigid registration respectively. 9 beams IMRT plan with equal division angle were designed for every patients, and the prescription dose for tumor target was set as 72Gy (2.4Gy/ fration). The boundary display, volume and dose-volume indices of each organ were compared between on MRI and CT images. Results: Compared to CT, MRI showed clearer boundary of brainstem, spinal cord, the deep lobe of Parotid gland and the optical nerve in canal. MRI images increase the volume of lens, optical nerve, while reducing the volume of eye slightly, and the maximum dose of lens, the mean dose of eyes and optical raised in different percentage, while there was no statistical differences were found. The left and right parotid volume on MRI increased by 7.07%, 8.13%, and the mean dose raised by 14.95% (4.01Gy), 18.76% (4.95Gy) with statistical significant difference (p<0.05). The brainstem volume reduced by 9.33% (p<0.05), and the dose of 0.1cm3 volume (D0.1cm3) reduced by mean 8.46% (4.32Gy), and D0.1cm3 of spinal cord increased by 1.5Gy on MRI. Conclusion: It is credible to evaluate the radiation dose of lens, eye and the spinal cord, while it should be necessary to evaluate the dose of brainstem, parotid and the optical nerve applying MRI images sometime, it will be more meaningful for these organs with high risk of radiation injury.

  9. Evaluation of different doses of gamma radiation on physicochemical characteristics of peach Prunus persica (cv. Chimarrita) minimally processed

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Ana Claudia S.; Silva, Lucia C.A.S.; Perecin, Thalita Neme; Arthur, Valter; Harder, Marcia N.C. [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Dept. de Radiobiologia e Ambiente], e-mail: acsoliveira@usp.br, e-mail: arthur@cena.usp.br; Mansi, Debora N.; Canniatti-Brazaca, Solange G. [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Dept. de Agroindustria, Alimentos e Nutricao

    2009-07-01

    The objective was to evaluate the effect of different doses of gamma radiation on the physico-chemical characteristics of peach Prunus persica (cv. Chimarrita) minimally processed, to increase the useful life of the fruit. The peaches were purchased at Ceasa of Campinas/SP and taken to the Laboratory of Radiobiology and Environment of CENA/USP (Piracicaba/SP), which were washed in tap water, peeled and cut into four pieces. The pieces of peach were dipped in sodium hypochlorite solution of 15 mL/L for 4 minutes and dry in a plastic support. Then it were placed in plastic containers (polypropylene). Subsequently, they were irradiated in a Cobalt-60 source, type Gammacell-220 (dose rate of 0,543 kGy/hour) with doses of: 0 (control), 1.0 and 2.0 kGy and stored at a temperature of 8 deg C. The experimental was developed entirely at random with 3 replicates for each treatment. For the statistic analysis was using the Tuckey test at 5% level of probability. Subsequently, analysis was carried out: color factors (l, a, b), pH, soluble solids (deg Brix), acidity and vitamin C. The tests were performed at 1, 3 and 6 days after irradiation. According to the results concluded that the analysis of color and acidity there was no significant difference between treatments, however, for the soluble solids (deg Brix), vitamin C and texture significant difference showing a decrease proportional to increasing doses of radiation and storage time. But the pH increased in relation to dose and during the analysis. (author)

  10. Atmospheric radiation flight dose rates

    Science.gov (United States)

    Tobiska, W. K.

    2015-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has been conducting space weather observations of the atmospheric radiation environment at aviation altitudes that will eventually be transitioned into air traffic management operations. The Automated Radiation Measurements for Aerospace Safety (ARMAS) system and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) both are providing dose rate measurements. Both activities are under the ARMAS goal of providing the "weather" of the radiation environment to improve aircraft crew and passenger safety. Over 5-dozen ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. Flight altitudes now exceed 60,000 ft. and extend above commercial aviation altitudes into the stratosphere. In this presentation we describe recent ARMAS and USEWX results.

  11. Evolution of radon dose evaluation

    Directory of Open Access Journals (Sweden)

    Fujimoto Kenzo

    2004-01-01

    Full Text Available The historical change of radon dose evaluation is reviewed based on the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR reports. Since 1955, radon has been recognized as one of the important sources of exposure of the general public. However, it was not really understood that radon is the largest dose contributor until 1977 when a new concept of effective dose equivalent was introduced by International Commission on Radiological Protection. In 1982, the dose concept was also adapted by UNSCEAR and evaluated per caput dose from natural radiation. Many researches have been carried out since then. However, lots of questions have remained open in radon problems, such as the radiation weighting factor of 20 for alpha rays and the large discrepancy of risk estimation among dosimetric and epidemiological approaches.

  12. Radiation dose monitoring in the clinical routine

    Energy Technology Data Exchange (ETDEWEB)

    Guberina, Nika [UK Essen (Germany). Radiology

    2017-04-15

    Here we describe the first clinical experiences regarding the use of an automated radiation dose management software to monitor the radiation dose of patients during routine examinations. Many software solutions for monitoring radiation dose have emerged in the last decade. The continuous progress in radiological techniques, new scan features, scanner generations and protocols are the primary challenge for radiation dose monitoring software systems. To simulate valid dose calculations, radiation dose monitoring systems have to follow current trends and stay constantly up-to-date. The dose management software is connected to all devices at our institute and conducts automatic data acquisition and radiation dose calculation. The system incorporates 18 virtual phantoms based on the Cristy phantom family, estimating doses in newborns to adults. Dose calculation relies on a Monte Carlo simulation engine. Our first practical experiences demonstrate that the software is capable of dose estimation in the clinical routine. Its implementation and use have some limitations that can be overcome. The software is promising and allows assessment of radiation doses, like organ and effective doses according to ICRP 60 and ICRP 103, patient radiation dose history and cumulative radiation doses. Furthermore, we are able to determine local diagnostic reference doses. The radiation dose monitoring software systems can facilitate networking between hospitals and radiological departments, thus refining radiation doses and implementing reference doses at substantially lower levels.

  13. Dose specification for radiation therapy: dose to water or dose to medium?

    Science.gov (United States)

    Ma, C.-M.; Li, Jinsheng

    2011-05-01

    The Monte Carlo method enables accurate dose calculation for radiation therapy treatment planning and has been implemented in some commercial treatment planning systems. Unlike conventional dose calculation algorithms that provide patient dose information in terms of dose to water with variable electron density, the Monte Carlo method calculates the energy deposition in different media and expresses dose to a medium. This paper discusses the differences in dose calculated using water with different electron densities and that calculated for different biological media and the clinical issues on dose specification including dose prescription and plan evaluation using dose to water and dose to medium. We will demonstrate that conventional photon dose calculation algorithms compute doses similar to those simulated by Monte Carlo using water with different electron densities, which are close (doses to media but significantly different (up to 11%) from doses to water converted from doses to media following American Association of Physicists in Medicine (AAPM) Task Group 105 recommendations. Our results suggest that for consistency with previous radiation therapy experience Monte Carlo photon algorithms report dose to medium for radiotherapy dose prescription, treatment plan evaluation and treatment outcome analysis.

  14. Evaluation of low contrast resolution and radiation dose in abdominal CT protocols by a difference detail curve (DDC method

    Directory of Open Access Journals (Sweden)

    Sommer Christian

    2017-09-01

    Full Text Available The use of optimised CT protocols regarding radiation exposure is a legal requirement. Since low contrast visibility is intrinsically varying within the CT slice, there is no adequate method for optimisation of dose and image quality. We developed a method to access image quality in a way that represents the situation closer to a real patient. This method is based on a novel difference detail curve (DDC phantom with low contrast objects representing native tissue contrast and contrast media with different densities and diameters. The position of the contrast objects have been evaluated by a noise level analysis of CT slices of different manufactures. The dose – length – product can be measured within the phantom simultaneously. For all tested manu-factures and CT protocols, the noise analysis revealed a similar spatial variation of the signal -to-noise ratio (SNR. For the DDC method, contrast steps of 6 (4-8 Hounsfield Units (HU are adequate. For the different CT units, comparable low contrast detectability is associated with remarkably varying dose levels (CTDI range from 8 to 18 mGy for native contrast and 9-16 mGy for contrast media. The novel DDC phantom is sensitive to protocol optimisations and therefore suitable for rating subtle effects caused by protocol optimisation.

  15. Evaluation of environmental contamination and estimated radiation doses for the return to residents' homes in Kawauchi Village, Fukushima prefecture.

    Directory of Open Access Journals (Sweden)

    Yasuyuki Taira

    Full Text Available To evaluate the environmental contamination and radiation exposure dose rates due to artificial radionuclides in Kawauchi Village, Fukushima Prefecture, the restricted area within a 30-km radius from the Fukushima Dai-ichi Nuclear Power Plant (FNPP, the concentrations of artificial radionuclides in soil samples, tree needles, and mushrooms were analyzed by gamma spectrometry. Nine months have passed since samples were collected on December 19 and 20, 2011, 9 months after the FNPP accident, and the prevalent dose-forming artificial radionuclides from all samples were (134Cs and (137Cs. The estimated external effective doses from soil samples were 0.42-7.2 µSv/h (3.7-63.0 mSv/y within the 20-km radius from FNPP and 0.0011-0.38 µSv/h (0.010-3.3 mSv/y within the 20-30 km radius from FNPP. The present study revealed that current levels are sufficiently decreasing in Kawauchi Village, especially in areas within the 20- to 30-km radius from FNPP. Thus, residents may return their homes with long-term follow-up of the environmental monitoring and countermeasures such as decontamination and restrictions of the intake of foods for reducing unnecessary exposure. The case of Kawauchi Village will be the first model for the return to residents' homes after the FNPP accident.

  16. Evaluation of radiation dose reduction during CT scans by using bismuth oxide and nano-barium sulfate shields

    Science.gov (United States)

    Seoung, Youl-Hun

    2015-07-01

    The purpose of the present study was to evaluate the radiation dose reduction and the image quality during CT scanning by using a new dose reduction fiber sheet (DRFS) with commercially available bismuth shields. These DRFS, were composed of nano-barium sulfate (BaSO4) filling the gaps left by the large bismuth oxide (Bi2O3) particles. The radiation dose was measured five times at a direction of 12 o'clock from the center of the polymethyl methacrylate (PMMA) head phantom by using a CT ionization chamber to calculate an average value. The image quality of measured CT transverse images of the PMMA head phantom depended on the X-ray tube voltage and the type of shielding. Two regions of interest in the CT transverse images were chosen, one from the right area and the other from the left area under the surface of the PMMA head phantom and at a distance of ion chamber holes located in a direction of 12 o'clock from the center of the PMMA head phantom. The results of this study showed that the new DRFS shields could reduce the dosages by 15.61%, 23.05%, and 22.71% at 90 kVp, 120 kVp, and 140 kVp, respectively, than with these of a conventional bismuth shield of the same thickness while maintaining image quality. In addition, the DRFSs produced were about 25% thinness than conventional bismuth. We conclude, therefore, that a DRFS can replace conventional bismuth as a new shield.

  17. Minimizing exposure to radiation in invasive cardiology using modern dose-reduction technology: evaluation of the real-life effects.

    Science.gov (United States)

    Faroux, Laurent; Blanpain, Thierry; Nazeyrollas, Pierre; Tassan-Mangina, Sophie; Herce, Benoît; Tourneux, Christophe; Metz, Damien

    2017-09-01

    We aimed to measure the reduction in the estimated dose of radiation received by patients that can be achieved using dose-reduction technology (ClarityIQ, Philips Healthcare, The Netherlands), among all patients undergoing invasive cardiology procedures. Medical procedures remain the primary source of exposure to ionizing radiation in the general population. The study population comprised all patients (without exclusion criteria) undergoing invasive coronary procedures over a 1-year study period in a large referral centre equipped with two catheterization laboratories (cathlabs). Both cathlabs (A and B) were equipped with the Allura Xper FD10 imaging system (Philips Healthcare, The Netherlands), but only Cathlab B was equipped with ClarityIQ technology. The primary endpoint was the estimated total dose of radiation received by the patient, as assessed by Air Kerma (AK) and dose area product (DAP). In total, 2095 invasive coronary procedures were analyzed. The patients who underwent procedures in Cathlab B received an average estimated dose that was 23% (AK) and 43% (DAP) lower than the dose received by patients undergoing procedures in Cathlab A (P age. In our study, the ClarityIQ technology reduced the estimated radiation dose received by patients by 23-43%, according to the method of measurement. © 2017 Wiley Periodicals, Inc.

  18. Evaluation of radiation dose to pediatric patients during certain special procedures

    Science.gov (United States)

    Sulieman, A.; Alzimami, K.; Elhag, B.; Babikir, E.; Alsafi, K.

    2014-11-01

    This study was intended to measure pediatric entrance surface air kerma (ESAK) and effective dose during micturating cystourethrography (MCU), intravenous urography (IVU) and barium studies (barium meal, enema, and swallow) and to propose a local diagnostic reference level (DRL). ESAK was measured for patients using calibrated thermoluminescent dosimeters (TLDs, GR200A). Effective doses (E) were calculated using the National Radiological Protection Board (NRPB) software. A total of 236 special pediatric procedures were investigated. 21.7% of the sample comprised barium procedures, 18.6% were MCU procedures while 59.5% of the sample were IVU procedures. The mean ESAK measurements (mGy) were 2.1±0.8, 3.0±23 and 1.2±0.2 for barium meal, enema and swallow in the same order. The mean patient dose for IVU procedures was 12.4±8.7 mGy per procedure and the mean patient dose per MCU procedure was 5.8±7 mGy. Local DRLs were proposed for all procedures. The patient doses in this study are within the reported values, suggesting that pediatric patients are adequately protected.

  19. Evaluation of absorbed radiation dose in mammography using Monte Carlo simulation; Avaliacao da dose absorvida em mamografia usando simulacao Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Bruno L.; Tomal, Alessandra [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Fisica Gleb Wataghin

    2016-07-01

    Mammography is the main tool for breast cancer diagnosis, and it is based on the use of X-rays to obtain images. However, the glandular tissue present within the breast is highly sensitive to ionizing radiation, and therefore requires strict quality control in order to minimize the absorbed dose. The quantification of the absorbed dose in the breast tissue can be done by using Monte Carlo simulation, which allows a detailed study of the deposition of energy in different regions of the breast. Besides, the results obtained from the simulation can be associated with experimental data and provide values of dose interest, such as the dose deposited in glandular tissue. (author)

  20. Low radiation dose non-contrast cardiac CT: is it of value in the evaluation of mechanical aortic valve

    Energy Technology Data Exchange (ETDEWEB)

    Bazeed, Mohamed Fayez (Dept. of Diagnostic Radiology, Faculty of Medicine, Mansoura Univ. (Egypt)), email: m_bazeed@yahoo.com; Moselhy, Mohamed Saleh (Cardiology Dept. Faculty of Medicine, Suez Canal Univ. (Egypt)); Rezk, Ahmad Ibrahim (Dept. of Cardiac Surgery, Faculty of Medicine, Aim Shams Univ. (Egypt)); Al-Murayeh, Mushabab Ayedh (Dept. of Cardiac Services, Armed Forces Hospitals Southern Region (Saudi Arabia))

    2012-05-15

    Background: Prosthetic bileaflet mechanical valve function has been traditionally evaluated using echocardiography and fluoroscopy. Multidetector computed tomography (MDCT) is a novel technique for cardiac evaluation. Purpose: To evaluate bileaflet mechanical aortic valves using a low-milliampere (mA), non-contrast MDCT protocol with a limited scan range. Material and Methods: Forty patients with a bileaflet mechanical aortic valve were evaluated using a non-contrast, low-mA, ECG-gated 64 MDCT protocol with a limited scan range. MDCT findings of opening and closing valve angles were correlated to fluoroscopy and echocardiography. Also, the valve visibility was evaluated on MDCT and fluoroscopy according to a 3-point grading scale. Results: The visualization score with the MDCT was significantly superior to the fluoroscopy (3 vs. 2.7). A strong correlation was noted between the opening (r = 0.82) and closing (r = 0.96) valve angles with MDCT and fluoroscopy without a statistically significant difference (P = 0.31 and 0.16, respectively). The mean effective radiation dose of the suggested protocol was 4 +- 0.5 mSv. Five valves were evaluated using transesophageal echocardiography because the valves were difficult to evaluate with transthoracic echocardiography, and all of these valves were evaluated optimally with MDCT. A high-pressure gradient was noted in nine valves, and the MDCT showed that seven of these valves inadequately opened, and two valves opened well, which resulted in patient valve mismatch. Incomplete valve closure was noted in five valves, and the echocardiography showed significant transvalvular regurgitation in all five valves. Conclusion: MDCT can provide a precise measurement of valve function and can potentially evaluate high-pressure gradients and transvalvular regurgitation

  1. CT evaluation of coronary artery stents with iterative image reconstruction: improvements in image quality and potential for radiation dose reduction.

    Science.gov (United States)

    Ebersberger, Ullrich; Tricarico, Francesco; Schoepf, U Joseph; Blanke, Philipp; Spears, J Reid; Rowe, Garrett W; Halligan, William T; Henzler, Thomas; Bamberg, Fabian; Leber, Alexander W; Hoffmann, Ellen; Apfaltrer, Paul

    2013-01-01

    Comparison of coronary artery stent assessment with cardiac CT angiography (cCTA) using traditional filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE), in both full- and half-radiation dose image data. Dual-source cCTA studies of 37 implanted stents were reconstructed at full- and half-radiation dose with FBP and SAFIRE. Half-dose data were based on projections from one DSCT detector. In-stent noise, signal-to-noise ratio (SNR), and stent-lumen attenuation increase ratio (SAIR) were measured and image quality graded. Stent volumes were measured to gauge severity of beam hardening artefacts. Full-dose SAFIRE reconstructions were superior to full-dose FBP vis-à-vis in-stent noise (21.2 ± 6.6 vs. 35.7 ± 17.5; P  0.05). Comparing half-dose SAFIRE with full-dose FBP, in-stent noise (26.7 ± 13.0 vs. 35.7 ± 17.5; P  0.05), stent volume (129.6 ± 57.3 vs. 129.8 ± 65.0 mm(3); P > 0.05), and image quality (3.5 ± 1.0 vs. 3.7 ± 1.1; P > 0.05) did not differ. Radiation dose decreased from 8.7 ± 5.2 to 4.3 ± 2.6 mSv. Iterative reconstruction significantly improves imaging of coronary artery stents by CT compared with FBP, even with half-radiation-dose data.

  2. Radiation dose to surgeons in theatre | van der Merwe | South ...

    African Journals Online (AJOL)

    Objectives. To evaluate the effects of ionising radiation and radiation limits, and measure radiation doses received by surgeons in theatre. Design. Thermoluminescent dosimeter measurements of accumulated dose to specific anatomical regions of a neurosurgeon, gastroenterologist and orthopaedic surgeon performing ...

  3. Comprehensive Evaluations of Cone-beam CT dose in Image-guided Radiation Therapy via GPU-based Monte Carlo simulations

    CERN Document Server

    Montanari, Davide; Silvestri, Chiara; Graves, Yan J; Yan, Hao; Cervino, Laura; Rice, Roger; Jiang, Steve B; Jia, Xun

    2013-01-01

    Cone beam CT (CBCT) has been widely used for patient setup in image guided radiation therapy (IGRT). Radiation dose from CBCT scans has become a clinical concern. The purposes of this study are 1) to commission a GPU-based Monte Carlo (MC) dose calculation package gCTD for Varian On-Board Imaging (OBI) system and test the calculation accuracy, and 2) to quantitatively evaluate CBCT dose from the OBI system in typical IGRT scan protocols. We first conducted dose measurements in a water phantom. X-ray source model parameters used in gCTD are obtained through a commissioning process. gCTD accuracy is demonstrated by comparing calculations with measurements in water and in CTDI phantoms. 25 brain cancer patients are used to study dose in a standard-dose head protocol, and 25 prostate cancer patients are used to study dose in pelvis protocol and pelvis spotlight protocol. Mean dose to each organ is calculated. Mean dose to 2% voxels that have the highest dose is also computed to quantify the maximum dose. It is fo...

  4. Radiation dose reduction in the evaluation of scoliosis: an application of digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kushner, D.C.; Cleveland, R.H.; Herman, T.E.; Zaleske, D.J.; Ehrlich, M.G.; Correia, J.A.

    1986-10-01

    This report documents the clinical testing of scanning beam digital radiography as an imaging method in patients with scoliosis. This type of digital imaging requires a skin exposure of only 2.4 mR (0.619 microC/kg) per image, compared with the lowest possible posteroanterior screen-film exposure of 10 mR (2.58 microC/kg) at the chest and 60 mR (15.48 microC/kg) at the lumbar spine. Digital radiographic and screen-film images were obtained on multiple test objects and 273 patients. Scoliosis measurements using screen-film radiographs and digital radiographs were comparable to within a mean difference of 1 degrees at many different degrees of severity. The low-dose digital images were found to be useful and accurate for the detection and measurement of scoliosis after the first screen-film radiographs have excluded tumors and structural abnormalities.

  5. Evaluation of scattered radiation emitted from X-ray security scanners on occupational dose to airport personnel

    Science.gov (United States)

    Dalah, Entesar; Fakhry, Angham; Mukhtar, Asma; Al Salti, Farah; Bader, May; Khouri, Sara; Al-Zahmi, Reem

    2017-06-01

    Based on security issues and regulations airports are provided with luggage cargo scanners. These scanners utilize ionizing radiation that in principle present health risks toward humans. The study aims to investigate the amount of backscatter produced by passenger luggage and cargo toward airport personnel who are located at different distances from the scanners. To approach our investigation a Thermo Electron Radeye-G probe was used to quantify the backscattered radiation measured in terms of dose-rate emitted from airport scanners, Measurements were taken at the entrance and exit positions of the X-ray tunnel at three different distances (0, 50, and 100 cm) for two different scanners; both scanners include shielding curtains that reduce scattered radiation. Correlation was demonstrated using the Pearson coefficient test. Measurements confirmed an inverse relationship between dose rate and distance. An estimated occupational accumulative dose of 0.88 mSv/y, and 2.04 mSv/y were obtained for personnel working in inspection of carry-on, and cargo, respectively. Findings confirm that the projected dose of security and engineering staff are being well within dose limits.

  6. Reprint of 'Evaluation of Scattered Radiation Emitted From X-ray Security Scanners on Occupational Dose to Airport Personnel'

    Science.gov (United States)

    Dalah, Entesar; Fakhry, Angham; Mukhtar, Asma; Al Salti, Farah; Bader, May; Khouri, Sara; Al-Zahmi, Reem

    2017-11-01

    Based on security issues and regulations airports are provided with luggage cargo scanners. These scanners utilize ionizing radiation that in principle present health risks toward humans. The study aims to investigate the amount of backscatter produced by passenger luggage and cargo toward airport personnel who are located at different distances from the scanners. To approach our investigation a Thermo Electron Radeye-G probe was used to quantify the backscattered radiation measured in terms of dose-rate emitted from airport scanners, Measurements were taken at the entrance and exit positions of the X-ray tunnel at three different distances (0, 50, and 100 cm) for two different scanners; both scanners include shielding curtains that reduce scattered radiation. Correlation was demonstrated using the Pearson coefficient test. Measurements confirmed an inverse relationship between dose rate and distance. An estimated occupational accumulative dose of 0.88 mSv/y, and 2.04 mSv/y were obtained for personnel working in inspection of carry-on, and cargo, respectively. Findings confirm that the projected dose of security and engineering staff are being well within dose limits.

  7. Evaluation of image quality and lesion perception by human readers on 3D CT colonography: comparison of standard and low radiation dose.

    Science.gov (United States)

    Fisichella, Valeria A; Båth, Magnus; Allansdotter Johnsson, Ase; Jäderling, Fredrik; Bergsten, Tommy; Persson, Ulf; Mellingen, Kristin; Hellström, Mikael

    2010-03-01

    We compared the prevalence of noise-related artefacts and lesion perception on three-dimensional (3D) CT colonography (CTC) at standard and low radiation doses. Forty-eight patients underwent CTC (64 x 0.625 mm collimation; tube rotation time 0.5 s; automatic tube current modulation: standard dose 40-160 mA, low dose 10-50 mA). Low- and standard-dose acquisitions were performed in the supine position, one after the other. The presence of artefacts (cobblestone and snow artefacts, irregularly delineated folds) and the presence of polyps were evaluated by five radiologists on 3D images at standard dose, the original low dose and a modified low dose, i.e. after manipulation of opacity on 3D. The mean effective dose was 3.9 +/- 1.3 mSv at standard dose and 1.03 +/- 0.4 mSv at low dose. The number of images showing cobblestone artefacts and irregularly delineated folds at original and modified low doses was significantly higher than at standard dose (P or =6 mm. Reduction of the effective dose to 1 mSv significantly affects image quality on 3D CTC, but the perception of > or =6 mm lesions is not significantly impaired.

  8. Effect of chronic low dose natural radiation in human peripheral blood mononuclear cells: Evaluation of DNA damage and repair using the alkaline comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P.R. Vivek, E-mail: prvkumar06@gmail.com [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Seshadri, M. [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Jaikrishan, G. [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Das, Birajalaxmi [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-05-15

    Highlights: • Effect of chronic low dose natural radiation in radio adaptive response studied. • PBMCs of subjects from NLNRA and HLNRA were challenged with gamma radiation. • DNA damage and repair in PBMCs was compared using the alkaline comet assay. • Significant reduction in DNA damage in subjects of high dose group from HLNRA noted. • Probable induction of an in vivo radio adaptive response in subjects from HLNRA. - Abstract: This study investigates whether peripheral blood mononuclear cells (PBMCs) from inhabitants of Kerala in southwest India, exposed to chronic low dose natural radiation in vivo (>1 mSv year{sup −1}), respond with a radioadaptive response to a challenging dose of gamma radiation. Toward this goal, PBMCs isolated from 77 subjects from high-level natural radiation areas (HLNRA) and 37 subjects from a nearby normal level natural radiation area (NLNRA) were challenged with 2 Gy and 4 Gy gamma radiation. Subjects from HLNRA were classified based on the mean annual effective dose received, into low dose group (LDG) and high dose group (HDG) with mean annual effective doses of 2.69 mSv (N = 43, range 1.07 mSv year{sup −1} to 5.55 mSv year{sup −1}) and 9.62 mSv (N = 34, range 6.07 mSv year{sup −1} to17.41 mSv year{sup −1}), respectively. DNA strand breaks and repair kinetics (at 7 min, 15 min and 30 min after 4 Gy) were evaluated using the alkaline single cell gel electrophoresis (comet) assay. Initial levels of DNA strand breaks observed after either a 2 Gy or a 4 Gy challenging dose were significantly lower in subjects of the HDG from HLNRA compared to subjects of NLNRA (2 Gy, P = 0.01; 4 Gy, P = 0.02) and LDG (2 Gy P = 0.01; 4 Gy, P = 0.05). Subjects of HDG from HLNRA showed enhanced rejoining of DNA strand breaks (HDG/NLNRA, P = 0.06) during the early stage of repair (within 7 min). However at later times a similar rate of rejoining of strand breaks was observed across the groups (HDG, LDG and NLNRA). Preliminary results from

  9. Evaluation of Kidney Stones with Reduced-Radiation Dose CT: Progress from 2011-2012 to 2015-2016-Not There Yet.

    Science.gov (United States)

    Weisenthal, Karrin; Karthik, Priyadarshini; Shaw, Melissa; Sengupta, Debapriya; Bhargavan-Chatfield, Mythreyi; Burleson, Judy; Mustafa, Adel; Kalra, Mannudeep; Moore, Christopher

    2018-02-01

    Purpose To determine if the use of reduced-dose computed tomography (CT) for evaluation of kidney stones increased in 2015-2016 compared with that in 2011-2012, to determine variability in radiation exposure according to facility for this indication, and to establish a current average radiation dose for CT evaluation for kidney stones by querying a national dose registry. Materials and Methods This cross-sectional study was exempt from institutional review board approval. Data were obtained from the American College of Radiology dose registry for CT examinations submitted from July 2015 to June 2016. Study descriptors consistent with single-phase unenhanced CT for evaluation of kidney stones and associated RadLex® Playbook identifiers (RPIDs) were retrospectively identified. Facilities actively submitting data on kidney stone-specific CT examinations were included. Dose metrics including volumetric CT dose index, dose-length product, and size-specific dose estimate, when available, were reported, and a random effects model was run to account for clustering of CT examinations at facilities. A z-ratio was calculated to test for a significant difference between the proportion of reduced-radiation dose CT examinations (defined as those with a dose-length product of 200 mGy · cm or less) performed in 2015-2016 and the proportion performed in 2011-2012. Results Three hundred four study descriptors for kidney stone CT corresponding to data from 328 facilities that submitted 105 334 kidney stone CT examinations were identified. Reduced-dose CT examinations accounted for 8040 of 105 334 (7.6%) CT examinations, a 5.6% increase from the 1010 of 49 903 (2%) examinations in 2011-2012 (P kidney stones has increased since 2011-2012, but remains low; variability of radiation dose according to facility continues to be wide. National mean CT radiation exposure for evaluation of renal colic during 2015-2016 decreased relative to 2011-2012 values, but remained well above what is

  10. Evaluation of Radiation Doses Due to Consumption of Contaminated Food Items and Calculation of Food Class-Specific Derived Intervention Levels

    Energy Technology Data Exchange (ETDEWEB)

    Heinzelman, K M; Mansfield, W G

    2010-04-27

    This document evaluates the expected radiation dose due to the consumption of several specific food classes (dairy, meat, produce, etc.) contaminated with specific radionuclides, and relates concentration levels in food to the detection abilities of typical aboratory analysis/measurement methods. The attached charts present the limiting organ dose as a function of the radionuclide concentration in a particular food class, and allow the user to compare these concentrations and doses to typical analytical detection apabilities. The expected radiation dose depends on several factors: the age of the individual; the radionuclide present in the food; the concentration of the radionuclide in the food; and the amount of food consumed. Food consumption rates for individuals of various ges were taken from the 1998 United States Food and Drug Administration (FDA) document, Accidental Radioactive Contamination of HUman Food and Animal Feeds: Recommendations for State and Local Agencies. In that document, the FDA defines the erived Intervention Level (DIL), which is the concentration of a particular radionuclide in food that if consumed could result in an individual receiving a radiation dose exceeding the Protection Action Guide (PAG) thresholds for intervention. This document also resents odified, food class specific DIL, which is calculated using a somewhat modified version of the FDA's procedure. This document begins with an overview of the FDA's DIL calculation, followed by a description of the food class specific DIL calculations, and finally charts of the radiation dose per radioactivity concentration for several food class/radionuclide combinations.

  11. Video dosimetry: evaluation of X-radiation dose by video fluoroscopic image; Videodosimetria: avaliacao da dose da radiacao X atraves da imagem videofluroscopica

    Energy Technology Data Exchange (ETDEWEB)

    Nova, Joao Luiz Leocadio da [Universidade Federal, Rio de Janeiro, RJ (Brazil). Centro de Ciencias da Saude. Nucleo de Tecnologia Educacional para a Saude; Lopes, Ricardo Tadeu [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Lab. de Instrumentacao Nuclear

    1996-12-31

    A new methodology to evaluate the entrance surface dose on patients under radiodiagnosis is presented. A phantom is used in video fluoroscopic procedures in on line video signal system. The images are obtained from a Siemens Polymat 50 and are digitalized. The results show that the entrance surface dose can be obtained in real time from video imaging 3 refs., 2 figs., 2 tabs.

  12. Evaluation of TLD dose response compared to MCNP-5 simulation of diagnostic X ray equipment - radiation diagnostic image

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez G, R.; Cavalieri, T. A.; De Paiva, F.; Dalledone S, P. de T.; Yoriyaz, H. [Instituto de Pesquisas Energeticas e Nucleares, Centro de Engenharia Nuclear / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil); Rodrigues F, M. A. [Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de Dermatologia e Radioterapia, Av. Prof. Montenegro s/n, Rubiao Junior, 18601-970 Botucatu (Brazil); Vivolo, V., E-mail: chancez@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares, Gerencia de Metrologia das Radiacoes / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

    2014-08-15

    The thermo luminescent dosimeter (TLD) is used as a radiation dosimeter and can be used as environmental and staff personnel monitoring. The TLD measures ionizing radiation exposure by a process in which the amount of radiation collected by the dosimeter is converted in visible light when the crystal is heated. The amount of emitted light is proportional to the radiation exposure, and then the response of the TLD must be the related to the real dose. In this work it was used twenty four TLD 700 in order to obtain eight values of doses from a diagnostic X-ray equipment. The TLD-700 is a LiF TLD enriched with {sup 7}Li isotope. One way to compare and study the response of TLD is by Monte Carlo method, which has been used as a computational tool to solve problems stochastically. This method can be applied to any geometry, even those where the boundary conditions are unknown, making the method particularly useful to solve problems a priori. In this work it was modeled the X-ray tube exactly as the one used to irradiate the TLD, after the simulation and the TLD irradiation the results of dose value from both were compared. (Author)

  13. CT evaluation of coronary artery stents with iterative image reconstruction: improvements in image quality and potential for radiation dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Ebersberger, Ullrich [Medical University of South Carolina, Department of Radiology and Radiological Science and Division of Cardiology, Department of Medicine, Charleston, SC (United States); Heart Centre Munich-Bogenhausen, Department of Cardiology and Intensive Care Medicine, Munich (Germany); Tricarico, Francesco [Catholic University of the Sacred Heart, ' ' A. Gemelli' ' Hospital, Department of Bioimaging and Radiological Sciences, Rome (Italy); Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science and Division of Cardiology, Department of Medicine, Charleston, SC (United States); Medical University of South Carolina, Heart and Vascular Center, Charleston, SC (United States); Blanke, Philipp [Medical University of South Carolina, Department of Radiology and Radiological Science and Division of Cardiology, Department of Medicine, Charleston, SC (United States); University Hospital Freiburg, Department of Diagnostic Radiology, Freiburg (Germany); Spears, J.R.; Rowe, Garrett W.; Halligan, William T. [Medical University of South Carolina, Department of Radiology and Radiological Science and Division of Cardiology, Department of Medicine, Charleston, SC (United States); Henzler, Thomas; Apfaltrer, Paul [Medical University of South Carolina, Department of Radiology and Radiological Science and Division of Cardiology, Department of Medicine, Charleston, SC (United States); University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Institute of Clinical Radiology and Nuclear Medicine, Heidelberg (Germany); Bamberg, Fabian [University of Munich - Grosshadern Campus, Institute of Clinical Radiology, Munich (Germany); Leber, Alexander W. [University of Toronto, Institute for Cardiovascular Intervention and Imaging, Schulich Heart Center, Sunnybrook Health Science Centre, Toronto (Canada); Hoffmann, Ellen [Heart Centre Munich-Bogenhausen, Department of Cardiology and Intensive Care Medicine, Munich (Germany)

    2013-01-15

    Comparison of coronary artery stent assessment with cardiac CT angiography (cCTA) using traditional filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE), in both full- and half-radiation dose image data. Dual-source cCTA studies of 37 implanted stents were reconstructed at full- and half-radiation dose with FBP and SAFIRE. Half-dose data were based on projections from one DSCT detector. In-stent noise, signal-to-noise ratio (SNR), and stent-lumen attenuation increase ratio (SAIR) were measured and image quality graded. Stent volumes were measured to gauge severity of beam hardening artefacts. Full-dose SAFIRE reconstructions were superior to full-dose FBP vis-a-vis in-stent noise (21.2 {+-} 6.6 vs. 35.7 {+-} 17.5; P < 0.05), SNR (22.1 {+-} 8.6 vs. 14.3 {+-} 6.7; P < 0.05), SAIR (19.6 {+-} 17.6 vs. 33.4 {+-} 20.4%; P < 0.05), and image quality (4.2 {+-} 0.86 vs. 3.5 {+-} 1.0; P < 0.05). Stent volumes were lower measured with SAFIRE (119.9 {+-} 53.7 vs. 129.8 {+-} 65.0 mm{sup 3}; P > 0.05). Comparing half-dose SAFIRE with full-dose FBP, in-stent noise (26.7 {+-} 13.0 vs. 35.7 {+-} 17.5; P < 0.05) and SNR (18.2 {+-} 6.9 vs. 14.3 {+-} 6.7; P < 0.05) improved significantly. SAIR (31.6 {+-} 24.3 vs. 33.4 {+-} 20.4%; P > 0.05), stent volume (129.6 {+-} 57.3 vs. 129.8 {+-} 65.0 mm{sup 3}; P > 0.05), and image quality (3.5 {+-} 1.0 vs. 3.7 {+-} 1.1; P > 0.05) did not differ. Radiation dose decreased from 8.7 {+-} 5.2 to 4.3 {+-} 2.6 mSv. Iterative reconstruction significantly improves imaging of coronary artery stents by CT compared with FBP, even with half-radiation-dose data. (orig.)

  14. Monte Carlo evaluation of Acuros XB dose calculation Algorithm for intensity modulated radiation therapy of nasopharyngeal carcinoma

    Science.gov (United States)

    Yeh, Peter C. Y.; Lee, C. C.; Chao, T. C.; Tung, C. J.

    2017-11-01

    Intensity-modulated radiation therapy is an effective treatment modality for the nasopharyngeal carcinoma. One important aspect of this cancer treatment is the need to have an accurate dose algorithm dealing with the complex air/bone/tissue interface in the head-neck region to achieve the cure without radiation-induced toxicities. The Acuros XB algorithm explicitly solves the linear Boltzmann transport equation in voxelized volumes to account for the tissue heterogeneities such as lungs, bone, air, and soft tissues in the treatment field receiving radiotherapy. With the single beam setup in phantoms, this algorithm has already been demonstrated to achieve the comparable accuracy with Monte Carlo simulations. In the present study, five nasopharyngeal carcinoma patients treated with the intensity-modulated radiation therapy were examined for their dose distributions calculated using the Acuros XB in the planning target volume and the organ-at-risk. Corresponding results of Monte Carlo simulations were computed from the electronic portal image data and the BEAMnrc/DOSXYZnrc code. Analysis of dose distributions in terms of the clinical indices indicated that the Acuros XB was in comparable accuracy with Monte Carlo simulations and better than the anisotropic analytical algorithm for dose calculations in real patients.

  15. CT radiation dose and iterative reconstruction techniques.

    Science.gov (United States)

    Padole, Atul; Ali Khawaja, Ranish Deedar; Kalra, Mannudeep K; Singh, Sarabjeet

    2015-04-01

    1. CT radiation dose optimization is one of the major concerns for the scientific community. 2. CT image quality is dependent on the selected image reconstruction algorithm. 3. Iterative reconstruction algorithms have reemerged with the potential of radiation dose optimization by lowering image noise. 4. Tube current is the most common parameter used to reduce radiation dose along with iterative reconstruction. 5. Tube potential (kV) is also used for dose optimization with iterative reconstruction in CT angiography protocols and small patients.

  16. Low-Dose Pretreatment for Radiation Therapy

    OpenAIRE

    Blankenbecler, Richard

    2010-01-01

    In radiotherapy, a large radiation dose must be applied to both cancer and neighboring healthy cells. Recent experiments have shown that a low dose of ionizing radiation turns on certain protective mechanisms that allow a cell to better survive a subsequent high dose of radiation. This adaptive response can have important and positive consequences for radiotherapy. This paper describes a simple change in treatment procedures to make use of these beneficial effects. A low dose applied only to ...

  17. Study of radiation effects on the cell structure and evaluation of the dose delivered by x-ray and {alpha}-particles microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kosior, Ewelina; Cloetens, Peter [European Synchrotron Radiation Facility, F-38000 Grenoble (France); Deves, Guillaume; Ortega, Richard [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Bohic, Sylvain [European Synchrotron Radiation Facility, 38000 Grenoble (France); INSERM U-836 (Team 6: Synchrotron Radiation and Medical Research), Grenoble Institut of Neuroscience, F-38000 Grenoble (France)

    2012-12-24

    Hard X-ray fluorescence microscopy and magnified phase contrast imaging are combined to study radiation effects on cells. Experiments were performed on freeze-dried cells at the nano-imaging station ID22NI of the European synchrotron radiation facility. Quantitative phase contrast imaging provides maps of the projected mass and is used to evaluate the structural changes due to irradiation during X-ray fluorescence experiments. Complementary to phase contrast imaging, scanning transmission ion microscopy is performed and doses of all the experiments are compared. We demonstrate the sensitivity of the proposed approach to study radiation-induced damage at the sub-cellular level.

  18. Do dose area product meter measurements reflect radiation doses ...

    African Journals Online (AJOL)

    Enrique

    accurately measures the radiation emitted from the source. The study included the interventional radiolo ... mined as most sensitive to radiation. The use of a thyroid guard also decreases the effective dose by approx- ... al radiation is necessary. Thermo- luminescent dosimetry is used to measure radiation and the apparatus.

  19. Balancing Radiation and Contrast Media Dose in Single-Pass Abdominal Multidetector CT: Prospective Evaluation of Image Quality.

    Science.gov (United States)

    Camera, Luigi; Romano, Federica; Liccardo, Immacolata; Liuzzi, Raffaele; Imbriaco, Massimo; Mainenti, Pier Paolo; Pizzuti, Laura Micol; Segreto, Sabrina; Maurea, Simone; Brunetti, Arturo

    2015-11-01

    As both contrast and radiation dose affect the quality of CT images, a constant image quality in abdominal contrast-enhanced multidetector computed tomography (CE-MDCT) could be obtained balancing radiation and contrast media dose according to the age of the patients. Seventy-two (38 Men; 34 women; aged 20-83 years) patients underwent a single-pass abdominal CE-MDCT. Patients were divided into three different age groups: A (20-44 years); B (45-65 years); and C (>65 years). For each group, a different noise index (NI) and contrast media dose (370 mgI/mL) was selected as follows: A (NI, 15; 2.5 mL/kg), B (NI, 12.5; 2 mL/kg), and C (NI, 10; 1.5 mL/kg). Radiation exposure was reported as dose-length product (DLP) in mGy × cm. For quantitative analysis, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated for both the liver (L) and the abdominal aorta (A). Statistical analysis was performed with a one-way analysis of variance. Standard imaging criteria were used for qualitative analysis. Although peak hepatic enhancement was 152 ± 16, 128 ± 12, and 101 ± 14 Hounsfield units (P contrast media dose (mL) administered were 476 ± 147 and 155 ± 27 for group A, 926 ± 291 and 130 ± 16 for group B, and 1981 ± 451 and 106 ± 15 for group C, respectively (P contrast media dose administered to patients of different age. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  20. Evaluation of the effective dose in an anthropomorphic phantom in radiation emergencies; Avaliacao da dose efetiva em um fantoma antropomorfico em situacoes de emergencia radiologica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, L.K.; Santos, D.S., E-mail: liviatelecom@hotmail.com [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    This study aims to perform a modeling of the human anatomy using Voxel models applied to Monte Carlo code and the Visual Monte Carlo software, simulating irradiation of the human body, so you can make the dose assessment in individuals who have been exposed to any external ionizing radiation source. Making the future, an assessment of both results with limits of validity of TECDOC-1162 expressions of the IAEA in case of point source.

  1. Optimization of hybrid iterative reconstruction level and evaluation of image quality and radiation dose for pediatric cardiac computed tomography angiography

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lin; Liang, Changhong [Southern Medical University, Guangzhou (China); Guangdong Academy of Medical Sciences, Dept. of Radiology, Guangdong General Hospital, Guangzhou (China); Zhuang, Jian [Guangdong Academy of Medical Sciences, Dept. of Cardiac Surgery, Guangdong Cardiovascular Inst., Guangdong Provincial Key Lab. of South China Structural Heart Disease, Guangdong General Hospital, Guangzhou (China); Huang, Meiping [Guangdong Academy of Medical Sciences, Dept. of Radiology, Guangdong General Hospital, Guangzhou (China); Guangdong Academy of Medical Sciences, Dept. of Catheterization Lab, Guangdong Cardiovascular Inst., Guangdong Provincial Key Lab. of South China Structural Heart Disease, Guangdong General Hospital, Guangzhou (China); Liu, Hui [Guangdong Academy of Medical Sciences, Dept. of Radiology, Guangdong General Hospital, Guangzhou (China)

    2017-01-15

    Hybrid iterative reconstruction can reduce image noise and produce better image quality compared with filtered back-projection (FBP), but few reports describe optimization of the iteration level. We optimized the iteration level of iDose{sup 4} and evaluated image quality for pediatric cardiac CT angiography. Children (n = 160) with congenital heart disease were enrolled and divided into full-dose (n = 84) and half-dose (n = 76) groups. Four series were reconstructed using FBP, and iDose{sup 4} levels 2, 4 and 6; we evaluated subjective quality of the series using a 5-grade scale and compared the series using a Kruskal-Wallis H test. For FBP and iDose{sup 4}-optimal images, we compared contrast-to-noise ratios (CNR) and size-specific dose estimates (SSDE) using a Student's t-test. We also compared diagnostic-accuracy of each group using a Kruskal-Wallis H test. Mean scores for iDose{sup 4} level 4 were the best in both dose groups (all P < 0.05). CNR was improved in both groups with iDose{sup 4} level 4 as compared with FBP. Mean decrease in SSDE was 53% in the half-dose group. Diagnostic accuracy for the four datasets were in the range 92.6-96.2% (no statistical difference). iDose{sup 4} level 4 was optimal for both the full- and half-dose groups. Protocols with iDose{sup 4} level 4 allowed 53% reduction in SSDE without significantly affecting image quality and diagnostic accuracy. (orig.)

  2. Evaluation of radiation doses and associated risk from the Fukushima nuclear accident to marine biota and human consumers of seafood

    Science.gov (United States)

    Fisher, Nicholas S.; Beaugelin-Seiller, Karine; Hinton, Thomas G.; Baumann, Zofia; Madigan, Daniel J.; Garnier-Laplace, Jacqueline

    2013-01-01

    Radioactive isotopes originating from the damaged Fukushima nuclear reactor in Japan following the earthquake and tsunami in March 2011 were found in resident marine animals and in migratory Pacific bluefin tuna (PBFT). Publication of this information resulted in a worldwide response that caused public anxiety and concern, although PBFT captured off California in August 2011 contained activity concentrations below those from naturally occurring radionuclides. To link the radioactivity to possible health impairments, we calculated doses, attributable to the Fukushima-derived and the naturally occurring radionuclides, to both the marine biota and human fish consumers. We showed that doses in all cases were dominated by the naturally occurring alpha-emitter 210Po and that Fukushima-derived doses were three to four orders of magnitude below 210Po-derived doses. Doses to marine biota were about two orders of magnitude below the lowest benchmark protection level proposed for ecosystems (10 µGy⋅h−1). The additional dose from Fukushima radionuclides to humans consuming tainted PBFT in the United States was calculated to be 0.9 and 4.7 µSv for average consumers and subsistence fishermen, respectively. Such doses are comparable to, or less than, the dose all humans routinely obtain from naturally occurring radionuclides in many food items, medical treatments, air travel, or other background sources. Although uncertainties remain regarding the assessment of cancer risk at low doses of ionizing radiation to humans, the dose received from PBFT consumption by subsistence fishermen can be estimated to result in two additional fatal cancer cases per 10,000,000 similarly exposed people. PMID:23733934

  3. A review of dosimetry used in epidemiological studies considered to evaluate the linear no-threshold (LNT) dose-response model for radiation protection.

    Science.gov (United States)

    Till, John E; Beck, Harold L; Grogan, Helen A; Caffrey, Emily A

    2017-10-01

    Accurate dosimetry is key to deriving the dose response from radiation exposure in an epidemiological study. It becomes increasingly important to estimate dose as accurately as possible when evaluating low dose and low dose rate as the calculation of excess relative risk per Gray (ERR/Gy) is very sensitive to the number of excess cancers observed, and this can lead to significant errors if the dosimetry is of poor quality. By including an analysis of the dosimetry, we gain a far better appreciation of the robustness of the work from the standpoint of its value in supporting the shape of the dose response curve at low doses and low dose rates. This article summarizes a review of dosimetry supporting epidemiological studies currently being considered for a re-evaluation of the linear no-threshold assumption as a basis for radiation protection. The dosimetry for each study was evaluated based on important attributes from a dosimetry perspective. Our dosimetry review consisted of dosimetry supporting epidemiological studies published in the literature during the past 15 years. Based on our review, it is clear there is wide variation in the quality of the dosimetry underlying each study. Every study has strengths and weaknesses. The article describes the results of our review, explaining which studies clearly stand out for their strengths as well as common weaknesses among all investigations. To summarize a review of dosimetry used in epidemiological studies being considered by the National Council on Radiation Protection and Measurements (NCRP) in an evaluation of the linear no-threshold dose-response model that underpins the current framework of radiation protection. The authors evaluated each study using criteria considered important from a dosimetry perspective. The dosimetry analysis was divided into the following categories: (1) general study characteristics, (2) dose assignment, (3) uncertainty, (4) dose confounders (5) dose validation, and (6) strengths and

  4. RADIATION MONITORING THE INDUSTRIAL NUCLEAR EXPLOSION SITES AND EVALUATION OF THE DOSES TO THE CRITICAL GROUPS OF POPULATION

    Directory of Open Access Journals (Sweden)

    V. P. Ramzaev

    2010-01-01

    Full Text Available The paper outlines the key elements of the radiation monitoring system at the sites of industrial nuclear explosions in the Russian Federation. The proposed recommendations describe sampling and measurements procedures, registration of the results and their cartographic presentation. The algorithm and formulas for calculating the doses to the critical groups of population are given. The recommendations are proposed, first of all, for practical application by the regional units of the State Sanitary Inspection.

  5. Evaluation of Radiation Exposure to Staff and Environment Dose from [18F]-FDG in PET/CT and Cyclotron Center using Thermoluminescent Dosimetry

    Directory of Open Access Journals (Sweden)

    Zargan S.

    2017-03-01

    Full Text Available Background: PET/CT imaging using [18F]-FDG is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. Essential consideration must be taken for radiation staff due to high gamma radiation in PET/CT and cyclotron center. The aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in PET/CT and cyclotron center. Materials and Methods: 80 patients participated in this study. Thermoluminescence, electronic personal dosimeter and Geiger–Muller dosimeter were also utilized for measurement purpose. Results: The mean annual equivalent organ dose for scanning operator with regard to lens of eyes, thyroid, breast and finger according to mean±SD value, were 0.262±0.044, 0.256±0.046, 0.257±0.040 and 0.316±0.118, respectively. The maximum and minimum estimated annual whole body doses were observed for injector and the chemist group with values of (3.98±0.021 mSv/yr and (1.64±0.014 mSv/yr, respectively. The observed dose rates were 5.67 µSv/h in uptake room at the distance of 0.5 meter from the patient whereas the value 4.94 and 3.08 µSv/h were recorded close to patient’s head in PET/CT room and 3.5 meter from the reception desk. Conclusion: In this study, the injector staff and scanning operator received the first high level and second high level of radiation. This study confirmed that low levels of radiation dose were received by all radiation staff during PET/CT procedure using 18F-FDG due to efficient shielding and using trained radiation staff in PET/CT and cyclotron center of Masih Daneshvari hospital.

  6. Evaluation of Radiation Exposure to Staff and Environment Dose from [18F]-FDG in PET/CT and Cyclotron Center using Thermoluminescent Dosimetry.

    Science.gov (United States)

    Zargan, S; Ghafarian, P; Shabestani Monfared, A; Sharafi, A A; Bakhshayeshkaram, M; Ay, M R

    2017-03-01

    PET/CT imaging using [18F]-FDG is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. Essential consideration must be taken for radiation staff due to high gamma radiation in PET/CT and cyclotron center. The aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in PET/CT and cyclotron center. 80 patients participated in this study. Thermoluminescence, electronic personal dosimeter and Geiger-Muller dosimeter were also utilized for measurement purpose. The mean annual equivalent organ dose for scanning operator with regard to lens of eyes, thyroid, breast and finger according to mean±SD value, were 0.262±0.044, 0.256±0.046, 0.257±0.040 and 0.316±0.118, respectively. The maximum and minimum estimated annual whole body doses were observed for injector and the chemist group with values of (3.98±0.021) mSv/yr and (1.64±0.014) mSv/yr, respectively. The observed dose rates were 5.67 µSv/h in uptake room at the distance of 0.5 meter from the patient whereas the value 4.94 and 3.08 µSv/h were recorded close to patient's head in PET/CT room and 3.5 meter from the reception desk. In this study, the injector staff and scanning operator received the first high level and second high level of radiation. This study confirmed that low levels of radiation dose were received by all radiation staff during PET/CT procedure using 18F-FDG due to efficient shielding and using trained radiation staff in PET/CT and cyclotron center of Masih Daneshvari hospital.

  7. SU-D-BRD-01: Cloud-Based Radiation Treatment Planning: Performance Evaluation of Dose Calculation and Plan Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Na, Y; Kapp, D; Kim, Y; Xing, L [Stanford University School of Medicine, Stanford, CA (United States); Suh, T [Catholic UniversityMedical College, Seoul, Seoul (Korea, Republic of)

    2014-06-01

    Purpose: To report the first experience on the development of a cloud-based treatment planning system and investigate the performance improvement of dose calculation and treatment plan optimization of the cloud computing platform. Methods: A cloud computing-based radiation treatment planning system (cc-TPS) was developed for clinical treatment planning. Three de-identified clinical head and neck, lung, and prostate cases were used to evaluate the cloud computing platform. The de-identified clinical data were encrypted with 256-bit Advanced Encryption Standard (AES) algorithm. VMAT and IMRT plans were generated for the three de-identified clinical cases to determine the quality of the treatment plans and computational efficiency. All plans generated from the cc-TPS were compared to those obtained with the PC-based TPS (pc-TPS). The performance evaluation of the cc-TPS was quantified as the speedup factors for Monte Carlo (MC) dose calculations and large-scale plan optimizations, as well as the performance ratios (PRs) of the amount of performance improvement compared to the pc-TPS. Results: Speedup factors were improved up to 14.0-fold dependent on the clinical cases and plan types. The computation times for VMAT and IMRT plans with the cc-TPS were reduced by 91.1% and 89.4%, respectively, on average of the clinical cases compared to those with pc-TPS. The PRs were mostly better for VMAT plans (1.0 ≤ PRs ≤ 10.6 for the head and neck case, 1.2 ≤ PRs ≤ 13.3 for lung case, and 1.0 ≤ PRs ≤ 10.3 for prostate cancer cases) than for IMRT plans. The isodose curves of plans on both cc-TPS and pc-TPS were identical for each of the clinical cases. Conclusion: A cloud-based treatment planning has been setup and our results demonstrate the computation efficiency of treatment planning with the cc-TPS can be dramatically improved while maintaining the same plan quality to that obtained with the pc-TPS. This work was supported in part by the National Cancer Institute (1

  8. An evaluation of dose equivalence between synchrotron microbeam radiation therapy and conventional broad beam radiation using clonogenic and cell impedance assays.

    Science.gov (United States)

    Ibahim, Mohammad Johari; Crosbie, Jeffrey C; Yang, Yuqing; Zaitseva, Marina; Stevenson, Andrew W; Rogers, Peter A W; Paiva, Premila

    2014-01-01

    High-dose synchrotron microbeam radiation therapy (MRT) has shown the potential to deliver improved outcomes over conventional broadbeam (BB) radiation therapy. To implement synchrotron MRT clinically for cancer treatment, it is necessary to undertake dose equivalence studies to identify MRT doses that give similar outcomes to BB treatments. To develop an in vitro approach to determine biological dose equivalence between MRT and BB using two different cell-based assays. The acute response of tumour and normal cell lines (EMT6.5, 4T1.2, NMuMG, EMT6.5ch, 4T1ch5, SaOS-2) to MRT (50-560 Gy) and BB (1.5-10 Gy) irradiation was investigated using clonogenic and real time cell impedance sensing (RT-CIS)/xCELLigence assays. MRT was performed using a lattice of 25 or 50 µm-wide planar, polychromatic kilovoltage X-ray microbeams with 200 µm peak separation. BB irradiations were performed using a Co60 teletherapy unit or a synchrotron radiation source. BB doses that would generate biological responses similar to MRT were calculated by data interpolation and verified by clonogenic and RT-CIS assays. For a given cell line, MRT equivalent BB doses identified by RT-CIS/xCELLigence were similar to those identified by clonogenic assays. Dose equivalence between MRT and BB were verified in vitro in two cell lines; EMT6.5ch and SaOS-2 by clonogenic assays and RT-CIS/xCELLigence. We found for example, that BB doses of 3.4±0.1 Gy and 4.40±0.04 Gy were radiobiologically equivalent to a peak, microbeam dose of 112 Gy using clonogenic and RT-CIS assays respectively on EMT6.5ch cells. Our data provides the first determination of biological dose equivalence between BB and MRT modalities for different cell lines and identifies RT-CIS/xCELLigence assays as a suitable substitute for clonogenic assays. These results will be useful for the safe selection of MRT doses for future veterinary and clinical trials.

  9. Dose reconstruction modeling for medical radiation workers

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yeong Chull; Cha, Eun Shil; Lee, Won Jin [Dept. of Preventive Medicine, Korea University, Seoul (Korea, Republic of)

    2017-04-15

    Exposure information is a crucial element for the assessment of health risk due to radiation. Radiation doses received by medical radiation workers have been collected and maintained by public registry since 1996. Since exposure levels in the remote past are greater concern, it is essential to reconstruct unmeasured doses in the past using known information. We developed retrodiction models for different groups of medical radiation workers and estimate individual past doses before 1996. Reconstruction models for past radiation doses received by medical radiation workers were developed, and the past doses were estimated. Using these estimates, organ doses should be calculated which, in turn, will be used to explore a wide range of health risks of medical occupational radiation exposure. Reconstruction models for past radiation doses received by medical radiation workers were developed, and the past doses were estimated. Using these estimates, organ doses should be calculated which, in turn, will be used to explore a wide range of health risks of medical occupational radiation exposure.

  10. Do dose area product meter measurements reflect radiation doses ...

    African Journals Online (AJOL)

    Enrique

    between radiation doses absorbed by health care workers and dose area product meter (DAP) measurements at Universitas Hospital, Bloemfontein. The DAP is an instrument which accurately measures the radiation emitted from the source. The study included the interventional radiolo- gists, radiographers and nurses ...

  11. [Evaluation of radiation exposure of personnel in an orthopaedic and trauma operation theatre using the new real-time dosimetry system "dose aware"].

    Science.gov (United States)

    Müller, M C; Strauss, A; Pflugmacher, R; Nähle, C P; Pennekamp, P H; Burger, C; Wirtz, D C

    2014-08-01

    There is a positive correlation between operation time and staff exposure to radiation during intraoperative use of C-arm fluoroscopy. Due to harmful effects of exposure to long-term low-dose radiation for both the patient and the operating team it should be kept to a minimum. AIM of this study was to evaluate a novel dosimeter system called Dose Aware® (DA) enabling radiation exposure feedback of the personal in an orthopaedic and trauma operation theatre in real-time. Within a prospective study over a period of four month, DA was applied by the operation team during 104 orthopaedic and trauma operations in which the C-arm fluoroscope was used in 2D-mode. During ten operation techniques, radiation exposure of the surgeon, the first assistant, the theatre nurse and the anaesthesiologist was evaluated. Seventy-three operations were analysed. The surgeon achieved the highest radiation exposure during dorsolumbar spinal osteosynthesis, kyphoplasty and screw fixation of sacral fractures. The first assistant received a higher radiation exposure compared to the surgeon during plate osteosynthesis of distal radius fractures (157 %), intramedullary nailing of pertrochanteric fractures (143 %) and dorsolumbar spinal osteosynthesis (240 %). During external fixation of ankle fractures (68 %) and screw fixation of sacral fractures (66 %) radiation exposure of the theatre nurse exceeded 50 % of the surgeon's radiation exposure. During plate osteosynthesis of distal radius fractures (157 %) and intramedullary splinting of clavicular fractures (115 %), the anaesthesiologist received a higher radiation exposure than the surgeon. The novel dosimeter system DA provides real-time radiation exposure feedback of the personnel in an orthopaedic and trauma operation theatre for the first time. Data of this study demonstrate that radiation exposure of the personnel depends on the operation type. The first assistant, the theatre nurse and the anaesthesiologist might be

  12. Converting low dose radiation to redox signaling

    OpenAIRE

    Pristov, Jelena Bogdanović; Spasić, Mihajlo; Spasojević, Ivan

    2013-01-01

    In contrast to the damaging effects of high doses, low dose radiation (UV, gamma) has been reported to provoke constructive changes in plants. However, the mechanisms by which plants recognize and respond to low dose radiation are not understood. We have shown recently that polygalacturonic acid, cell wall polysaccharide, converts the highly reactive product of radiation - hydroxyl radical into superoxide which may be further dismutated to hydrogen peroxide. Superoxide has been proposed to ac...

  13. Accuracy and Radiation Dose Reduction of Limited-Range CT in the Evaluation of Acute Appendicitis in Pediatric Patients.

    Science.gov (United States)

    Jin, Michael; Sanchez, Thomas R; Lamba, Ramit; Fananapazir, Ghaneh; Corwin, Michael T

    2017-09-01

    The purpose of this article is to determine the accuracy and radiation dose reduction of limited-range CT prescribed from the top of L2 to the top of the pubic symphysis in children with suspected acute appendicitis. We performed a retrospective study of 210 consecutive pediatric patients from December 11, 2012, through December 11, 2014, who underwent abdominopelvic CT for suspected acute appendicitis. Two radiologists independently reviewed the theoretic limited scans from the superior L2 vertebral body to the top of the pubic symphysis, to assess for visualization of the appendix, acute appendicitis, alternative diagnoses, and incidental findings. Separately, the same parameters were assessed on the full scan by the same two reviewers. Whole-body effective doses were determined for the full- and limited-range scans and were compared using the paired t test. The appendix or entire cecum was visualized on the limited scan in all cases, and no cases of acute appendicitis were missed on the simulated limited scan compared with the full scan. Two alternative diagnoses were missed with the limited scan: one case of hydronephrosis and one of acute acalculous cholecystitis. The mean effective dose for the original scan was 5.6 mSv and that for the simulated limited scan was 3.0 mSv, resulting in a dose reduction of 46.4% (p appendicitis and reduces the dose by approximately 46%.

  14. Radiation-dose estimates and hazard evaluations for inhaled airborne radionuclides. Annual progress report, July 1981-June 1982

    Energy Technology Data Exchange (ETDEWEB)

    Mewhinney, J.A.

    1983-06-01

    The objective was to conduct confirmatory research on aerosol characteristics and the resulting radiation dose distribution in animals following inhalation and to provide prediction of health consequences in humans due to airborne radioactivity which might be released in normal operations or under accident conditions during production of nuclear fuel composed of mixed oxides of U and Pu. Four research reports summarize the results of specific areas of research. The first paper details development of a method for determination of specific surface area of small samples of mixed oxide or pure PuO/sub 2/ particles. The second paper details the extension of the biomathematical model previously used to describe retention, distribution and excretion of Pu from these mixed oxide aerosols to include a description of Am and U components of these aerosols. The third paper summarizes the biological responses observed in radiation dose pattern studies in which dogs, monkeys and rate received inhalation exposures to either 750/sup 0/C heat treated UO/sub 2/ + PuO/sub 2/, 1750/sup 0/C heat-treated (U,Pu)O/sub 2/ or 850/sup 0/C heat-treated pure PuO/sub 2/. The fourth paper described dose-response studies in which rats were exposed to (U,Pu)O/sub 2/ or pure PuO/sub 2/. This paper updates earlier reports and summarizes the status of animals through approximately 650 days after inhalation.

  15. The use of adaptive statistical iterative reconstruction (ASiR) technique in evaluation of patients with cervical spine trauma: impact on radiation dose reduction and image quality.

    Science.gov (United States)

    Patro, Satya N; Chakraborty, Santanu; Sheikh, Adnan

    2016-01-01

    The aim of this study was to evaluate the impact of adaptive statistical iterative reconstruction (ASiR) technique on the image quality and radiation dose reduction. The comparison was made with the traditional filtered back projection (FBP) technique. We retrospectively reviewed 78 patients, who underwent cervical spine CT for blunt cervical trauma between 1 June 2010 and 30 November 2010. 48 patients were imaged using traditional FBP technique and the remaining 30 patients were imaged using the ASiR technique. The patient demographics, radiation dose, objective image signal and noise were recorded; while subjective noise, sharpness, diagnostic acceptability and artefacts were graded by two radiologists blinded to the techniques. We found that the ASiR technique was able to reduce the volume CT dose index, dose-length product and effective dose by 36%, 36.5% and 36.5%, respectively, compared with the FBP technique. There was no significant difference in the image noise (p = 0.39), signal (p = 0.82) and signal-to-noise ratio (p = 0.56) between the groups. The subjective image quality was minimally better in the ASiR group but not statistically significant. There was excellent interobserver agreement on the subjective image quality and diagnostic acceptability for both groups. The use of ASiR technique allowed approximately 36% radiation dose reduction in the evaluation of cervical spine without degrading the image quality. The present study highlights that the ASiR technique is extremely helpful in reducing the patient radiation exposure while maintaining the image quality. It is highly recommended to utilize this novel technique in CT imaging of different body regions.

  16. Adaption By Low Dose Radiation Exposure

    OpenAIRE

    Mitchel, Ron E.J.

    2015-01-01

    The procedures and dose limitations used for radiation protection in the nuclear industry are founded on the assumption that risk is directly proportional to dose, without a threshold. Based on this idea that any dose, no matter how small, will increase risk, radiation protection regulations generally attempt to reduce any exposure to ?as low as reasonably achievable? (ALARA). We know however, that these regulatory assumptions are inconsistent with the known biological effects of low doses. L...

  17. Radiobiological evaluation of simultaneously dose-escalated versus non-escalated intensity-modulated radiation therapy for patients with upper thoracic esophageal cancer

    Directory of Open Access Journals (Sweden)

    Huang BT

    2017-04-01

    Full Text Available Bao-Tian Huang,1,* Li-Li Wu,1,* Long-Jia Guo,1,* Liang-Yu Xu,1,* Rui-Hong Huang,1 Pei-Xian Lin,2 Jian-Zhou Chen,1,3 De-Rui Li,1 Chuang-Zhen Chen1 1Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, 2Department of Nosocomial Infection Management, The Second Affiliated Hospital of Shantou University Medical College, Shantou, People’s Republic of China; 3CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom *These authors contributed equally to this work Objective: To compare the radiobiological response between simultaneously dose-escalated and non-escalated intensity-modulated radiation therapy (DE-IMRT and NE-IMRT for patients with upper thoracic esophageal cancer (UTEC using radiobiological evaluation. Methods: Computed tomography simulation data sets for 25 patients pathologically diagnosed with primary UTEC were used in this study. DE-IMRT plan with an escalated dose of 64.8 Gy/28 fractions to the gross tumor volume (GTV and involved lymph nodes from 25 patients pathologically diagnosed with primary UTEC, was compared to an NE-IMRT plan of 50.4 Gy/28 fractions. Dose-volume metrics, tumor control probability (TCP, and normal tissue complication probability for the lung and spinal cord were compared. In addition, the risk of acute esophageal toxicity (AET and late esophageal toxicity (LET were also analyzed. Results: Compared with NE-IMRT plan, we found the DE-IMRT plan resulted in a 14.6 Gy dose escalation to the GTV. The tumor control was predicted to increase by 31.8%, 39.1%, and 40.9% for three independent TCP models. The predicted incidence of radiation pneumonitis was similar (3.9% versus 3.6%, and the estimated risk of radiation-induced spinal cord injury was extremely low (<0.13% in both groups. Regarding the esophageal toxicities, the estimated grade ≥2 and grade ≥3 AET predicted by the Kwint model were increased by 2.5% and 3.8%. Grade ≥2

  18. Experimental evaluation of neutron dose in radiotherapy patients: Which dose?

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Expósito, M., E-mail: mariateresa.romero@uab.cat; Domingo, C.; Ortega-Gelabert, O.; Gallego, S. [Grup de Recerca en Radiacions Ionizants (GRRI), Departament de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Sánchez-Doblado, F. [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009 (Spain); Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41009 (Spain)

    2016-01-15

    Purpose: The evaluation of peripheral dose has become a relevant issue recently, in particular, the contribution of secondary neutrons. However, after the revision of the Recommendations of the International Commission on Radiological Protection, there has been a lack of experimental procedure for its evaluation. Specifically, the problem comes from the replacement of organ dose equivalent by the organ-equivalent dose, being the latter “immeasurable” by definition. Therefore, dose equivalent has to be still used although it needs the calculation of the radiation quality factor Q, which depends on the unrestricted linear energy transfer, for the specific neutron irradiation conditions. On the other hand, equivalent dose is computed through the radiation weighting factor w{sub R}, which can be easily calculated using the continuous function provided by the recommendations. The aim of the paper is to compare the dose equivalent evaluated following the definition, that is, using Q, with the values obtained by replacing the quality factor with w{sub R}. Methods: Dose equivalents were estimated in selected points inside a phantom. Two types of medical environments were chosen for the irradiations: a photon- and a proton-therapy facility. For the estimation of dose equivalent, a poly-allyl-diglicol-carbonate-based neutron dosimeter was used for neutron fluence measurements and, additionally, Monte Carlo simulations were performed to obtain the energy spectrum of the fluence in each point. Results: The main contribution to dose equivalent comes from neutrons with energy higher than 0.1 MeV, even when they represent the smallest contribution in fluence. For this range of energy, the radiation quality factor and the radiation weighting factor are approximately equal. Then, dose equivalents evaluated using both factors are compatible, with differences below 12%. Conclusions: Quality factor can be replaced by the radiation weighting factor in the evaluation of dose

  19. Evaluation of dose uncertainty in radiation processing using EPR spectroscopy and butylated hydroxytoluene rods as dosimetry system

    Science.gov (United States)

    Alkhorayef, M.; Mansour, A.; Sulieman, A.; Alnaaimi, M.; Alduaij, M.; Babikir, E.; Bradley, D. A.

    2017-12-01

    Butylatedhydroxytoluene (BHT) rods represent a potential dosimeter in radiation processing, with readout via electron paramagnetic resonance (EPR) spectroscopy. Among the possible sources of uncertainty are those associated with the performance of the dosimetric medium and the conditions under which measurements are made, including sampling and environmental conditions. Present study makes estimate of the uncertainties, investigating physical response in different resonance regions. BHT, a white crystalline solid with a melting point of between 70-73 °C, was investigated using 60Co gamma irradiation over the dose range 0.1-100 kGy. The intensity of the EPR signal increases linearly in the range 0.1-35 kGy, the uncertainty budget for high doses being 3.3% at the 2σ confidence level. The rod form represents an excellent alternative dosimeter for high level dosimetry, of small uncertainty compared to powder form.

  20. Evaluation of the Comet Assay for Assessing the Dose-Response Relationship of DNA Damage Induced by Ionizing Radiation

    Science.gov (United States)

    Wang, Yan; Xu, Chang; Du, Li Qing; Cao, Jia; Liu, Jian Xiang; Su, Xu; Zhao, Hui; Fan, Fei-Yue; Wang, Bing; Katsube, Takanori; Fan, Sai Jun; Liu, Qiang

    2013-01-01

    Dose- and time-response curves were combined to assess the potential of the comet assay in radiation biodosimetry. The neutral comet assay was used to detect DNA double-strand breaks in lymphocytes caused by γ-ray irradiation. A clear dose-response relationship with DNA double-strand breaks using the comet assay was found at different times after irradiation (p < 0.001). A time-response relationship was also found within 72 h after irradiation (p < 0.001). The curves for DNA double-strand breaks and DNA repair in vitro of human lymphocytes presented a nice model, and a smooth, three-dimensional plane model was obtained when the two curves were combined. PMID:24240807

  1. Dose Assurance in Radiation Processing Plants

    DEFF Research Database (Denmark)

    Miller, Arne; Chadwick, K.H.; Nam, J.W.

    1983-01-01

    Radiation processing relies to a large extent on dosimetry as control of proper operation. This applies in particular to radiation sterilization of medical products and food treatment, but also during development of any other process. The assurance that proper dosimetry is performed at the radiat...... at the radiation processing plant can be obtained through the mediation of an international organization, and the IAEA is now implementing a dose assurance service for industrial radiation processing....

  2. Carcinogenesis induced by low-dose radiation

    Directory of Open Access Journals (Sweden)

    Piotrowski Igor

    2017-11-01

    Full Text Available Although the effects of high dose radiation on human cells and tissues are relatively well defined, there is no consensus regarding the effects of low and very low radiation doses on the organism. Ionizing radiation has been shown to induce gene mutations and chromosome aberrations which are known to be involved in the process of carcinogenesis. The induction of secondary cancers is a challenging long-term side effect in oncologic patients treated with radiation. Medical sources of radiation like intensity modulated radiotherapy used in cancer treatment and computed tomography used in diagnostics, deliver very low doses of radiation to large volumes of healthy tissue, which might contribute to increased cancer rates in long surviving patients and in the general population. Research shows that because of the phenomena characteristic for low dose radiation the risk of cancer induction from exposure of healthy tissues to low dose radiation can be greater than the risk calculated from linear no-threshold model. Epidemiological data collected from radiation workers and atomic bomb survivors confirms that exposure to low dose radiation can contribute to increased cancer risk and also that the risk might correlate with the age at exposure.

  3. BCC and Childhood Low Dose Radiation

    Directory of Open Access Journals (Sweden)

    Arash Beiraghi Toosi

    2014-10-01

    Full Text Available Skin cancer is a late complication of ionizing radiation. Two skin neoplasms prominent Basal Cell Carcinoma (BCC and Squamous Cell Carcinoma (SCC are the most famous complications of radiotherapy. Basal Cell Carcinoma (BCC is the most common human malignant neoplasm. Many genetic and environmental factors are involved in its onset. BCC is observed in sun-exposed areas of skin. Some patients with scalp BCC have had a history of scalp radiation for the treatment of tinea capitis in childhood. Evidence that ionizing radiation is carcinogenic first came from past reports of nonmelanoma skin cancers on the hands of workers using radiation devices. The total dose of radiation and irradiated site exposed to sunlight can lead to a short incubation period. It is not clear whether BCC in these cases has a more aggressive nature and requires a more aggressive resection of the lesion. The aim of this review was to evaluate the differences between BCC specification and treatment results between irradiated and nonirradiated patients.

  4. Radiation dose levels in pediatric chest CT: experience in 499 children evaluated with dual-source single-energy CT

    Energy Technology Data Exchange (ETDEWEB)

    Martine, Remy-Jardin; Colas, Lucie; Jean-Baptiste, Faivre; Remy, Jacques [CHU Lille (EA 2694) University of Lille, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Santangelo, Teresa [CHU Lille (EA 2694) University of Lille, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Bambino Gesu Children' s Hospital, Department of Imaging, Rome (Italy); Duhamel, Alain [University of Lille (EA 2694), Department of Biostatistics, CHU Lille, Lille (France); Deschildre, Antoine [CHU Lille - University of Lille, Department of Pediatric Pulmonology, Lille (France)

    2017-02-15

    The availability of dual-source technology has introduced the possibility of scanning children at lower kVp with a high-pitch mode, combining high-speed data acquisition and high temporal resolution. To establish the radiation dose levels of dual-source, single-energy chest CT examinations in children. We retrospectively recorded the dose-length product (DLP) of 499 consecutive examinations obtained in children <50 kg, divided into five weight groups: group 1 (<10 kg, n = 129); group 2 (10-20 kg, n = 176); group 3 (20-30 kg, n = 99), group 4 (30-40 kg, n = 58) and group 5 (40-49 kg, n = 37). All CT examinations were performed with high temporal resolution (75 ms), a high-pitch mode and a weight-adapted selection of the milliamperage. CT examinations were obtained at 80 kVp with a milliamperage ranging between 40 mAs and 90 mAs, and a pitch of 2.0 (n = 162; 32.5%) or 3.0 (n = 337; 67.5%). The mean duration of data acquisition was 522.8 ± 192.0 ms (interquartile range 390 to 610; median 490). In the study population, the mean CT dose index volume (CTDIvol{sub 32}) was 0.83 mGy (standard deviation [SD] 0.20 mGy; interquartile range 0.72 to 0.94; median 0.78); the mean DLP{sub 32} was 21.4 mGy.cm (SD 9.1 mGy.cm; interquartile range 15 to 25; median 19.0); and the mean size-specific dose estimate (SSDE) was 1.7 mGy (SD 0.4 mGy; interquartile range 1.5 to 1.9; median 1.7). The DLP{sub 32}, CTDI{sub vol32} and SSDE were found to be statistically significant in the five weight categories (P < 0.0001). This study establishes the radiation dose levels for dual-source, single-kVp chest CT from a single center. In the five weight categories, the median values varied 15-37 mGy.cm for the DLP{sub 32}, 0.78-1.25 mGy for the CTDI{sub vol32} and 1.6-2.1 mGy for the SSDE. (orig.)

  5. Potential radiation doses from 1994 Hanford Operations

    Energy Technology Data Exchange (ETDEWEB)

    Soldat, J.K.; Antonio, E.J.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the potential radiation doses to the public from releases originating at the Hanford Site. Members of the public are potentially exposed to low-levels of radiation from these effluents through a variety of pathways. The potential radiation doses to the public were calculated for the hypothetical MEI and for the general public residing within 80 km (50 mi) of the Hanford Site.

  6. An evaluation of surface-dose increase caused by the thermoplastic shell in head and neck radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Shin-ichi; Hayama, Kazuhide; Toyama, Michio; Ninomiya, Shuichi; Eguchi, Toru; Takase, Hiroshi; Maeda, Kadzuo (Nippon Dental Univ., Niigata (Japan) Faculty of Dentistry (Niigata))

    1992-10-01

    Some kinds of the thermoplastic shells have been developed to improve the reproducibility of patient immobilization in head and neck radiotherapy treatment. Due to a build-up layer of high energy photons, the consideration of the surface-dose under the shell is important in radiotherapy treatment planning. This paper presents the precise evaluation of the surface-dose affected by the shell. The therapy machine used was 2.8 MV linac X-ray. The shell used was mesh sheet type thermoplastic shell. The TPR (tissue peak ratio) in the build-up layer was measured in various irradiation fields under the conditions with or without a wedge filter. The coefficients m' and K's of the power function of the build-up region were obtained from the relation between TPR and the irradiation fields. As a result, the coefficients were approximately intermediate values between cobalt-60 [gamma]-ray and 4.3 MV X-ray. When a wedge filter was used, the coefficients shifted toward those of higher energy. Before obtaining the dose distribution under the thermoplastic shell, film response was tested under the conditions of various irradiation fields and use of a wedge filter. The results showed that the film response was constant enough for dosimetry in the build-up region. Digital surface-absorbed dose distribution images under the shell were obtained using the microphotometer-microcomputer system. The digital image demonstrated a meshy dose pattern under the shell. In the area of a higher absorbed dose, the dose increases were in the range of 40-50%. The differences depended on not only the irradiation field and presence of a wedge-filter, but especially on the extent of expansion of the thermoplastic material in making the shell mask. (author).

  7. Evaluation of image quality and radiation dose using gold nanoparticles and other clinical contrast agents in dual-energy Computed Tomography (CT): CT abdomen phantom

    Science.gov (United States)

    Zukhi, J.; Yusob, D.; Tajuddin, A. A.; Vuanghao, L.; Zainon, R.

    2017-05-01

    The aim of this study was to evaluate the image quality and radiation dose using commercial gold nanoparticles and clinical contrast agents in dual-energy Computed Tomography (CT). Five polymethyl methacrylate (PMMA) tubes were used in this study, where four tubes were filled with different contrast agents (barium, iodine, gadolinium, and gold nanoparticles). The fifth tube was filled with water. Two optically stimulated luminescence dosimeters (OSLD) were placed in each tube to measure the radiation dose. The tubes were placed in a fabricated adult abdominal phantom of 32 cm in diameter using PMMA. The phantom was scanned using a DECT at low energy (80 kV) and high energy (140 kV) with different pitches (0.6 mm and 1.0 mm) and different slice thickness (3.0 mm and 5.0 mm). The tube current was applied automatically using automatic exposure control (AEC) and tube current modulation recommended by the manufacturer (CARE Dose 4D, Siemens, Germany). The contrast-to-noise ratio (CNR) of each contrast agent was analyzed using Weasis software. Gold nanoparticles has highest atomic number (Z = 79) than barium (Z = 56), iodine (Z = 53) and gadolinium (Z = 64). The CNR value of each contrast agent increases when the slice thickness increases. The radiation dose obtained from this study decreases when the pitch increases. The optimal imaging parameters for gold nanoparticles and other clinical contrast agents is obtained at pitch value of 1.0 mm and slice thickness of 5.0 mm. Low noise and low radiation dose obtained at these imaging parameters. The optimal imaging parameters obtained in this study can be applied in multiple contrast agents imaging.

  8. Radiation dose to the eye lens

    DEFF Research Database (Denmark)

    Baun, Christina; Falch Braas, Kirsten; D. Nielsen, Kamilla

    2015-01-01

    Radiation Dose to the Eye Lens: Does Positioning Really Matter? C. Baun1, K. Falch1, K.D. Nielsen2, S. Shanmuganathan1, O. Gerke1, P.F. Høilund-Carlsen1 1Department of Nuclear Medicine, Odense University Hospital, Odense C, Denmark. 2University College Lillebaelt, Odense, Denmark. Aim: The scan...... field in oncology patients undergoing eyes-to-thighs PET/CT must always include the base of the scull according to department guidelines. The eye lens is sensitive to radiation exposure and if possible it should be avoided to scan the eye. If the patient’s head is kipped backwards during the scan one...... might avoid including the eye in the CT scan without losing sufficient visualization of the scull base. The aim of this study was to evaluate the possibility of decreasing the radiation dose to the eye lens, simply by changing the head position, when doing the PET/CT scan from the base of the scull...

  9. Poster - Thurs Eve-09: Evaluation of a commercial 2D ion-chamber array for intensity modulated radiation therapy dose measurements.

    Science.gov (United States)

    Mei, X; Bracken, G; Kerr, A

    2008-07-01

    Experimental verification of calculated dose from a treatment planning system is often essential for quality assurance (QA) of intensity modulated radiation therapy (IMRT). Film dosimetry and single ion chamber measurements are commonly used for IMRT QA. Film dosimetry has very good spatial resolution, but is labor intensive and absolute dose is not reliable. Ion chamber measurements are still required for absolute dose after measurements using films. Dosimeters based on 2D detector arrays that can measure 2D dose in real-time are gaining wider use. These devices provide a much easier and reliable tool for IMRT QA. We report the evaluation of a commercial 2D ion chamber array, including its basic performance characteristics, such as linearity, reproducibility and uniformity of relative ion chamber sensitivities, and comparisons between measured 2D dose and calculated dose with a commercial treatment planning system. Our analysis shows this matrix has excellent linearity and reproducibility, but relative sensitivities are tilted such that the +Y region is over sensitive, while the -Y region is under sensitive. Despite this behavior, our results show good agreement between measured 2D dose profiles and Eclipse planned data for IMRT test plans and a few verification plans for clinical breast field-in-field plans. The gamma values (3% or 3 mm distance-to-agreement) are all less than 1 except for one or two pixels at the field edge This device provides a fast and reliable stand-alone dosimeter for IMRT QA. © 2008 American Association of Physicists in Medicine.

  10. Genome Wide Evaluation of Normal Human Tissue in Response to Controlled, In vivo Low-Dose Low LET Ionizing Radiation Exposure: Pathways and Mechanisms Final Report, September 2013

    Energy Technology Data Exchange (ETDEWEB)

    Rocke, David M. [University of California Davis

    2013-09-09

    During course of this project, we have worked in several areas relevant to low-dose ionizing radiation. Using gene expression to measure biological response, we have examined the response of human skin exposed in-vivo to radation, human skin exposed ex-vivo to radiation, and a human-skin model exposed to radiation. We have learned a great deal about the biological response of human skin to low-dose ionizing radiation.

  11. A dosimetric evaluation of dose escalation for the radical treatment of locally advanced vulvar cancer by intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bloemers, Monique C.W.M., E-mail: c.bloemers@nki.nl [Department of Radiotherapy, the Netherlands Cancer Institute, Amsterdam (Netherlands); Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Portelance, Lorraine [Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Ruo, Russell; Parker, William [Department of Medical Physics, McGill University Health Centre, Montreal, Quebec (Canada); Souhami, Luis [Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada)

    2012-10-01

    The purpose of this planning study was to determine whether intensity-modulated radiation therapy (IMRT) reduces the radiation dose to organs at risk (OAR) when compared with 3D conventional radiation therapy (3D-CRT) in patients with vulvar cancer treated by irradiation. This study also investigated the use of sequential IMRT boost (seq-IMRT) and simultaneous integrated boost (SIB-IMRT) for dose escalation in the treatment of locally advanced vulvar cancer. Five vulvar cancer patients treated in the postoperative setting and 5 patients treated with definitive intent (def-group) were evaluated. For the postoperative group, 3D-CRT and IMRT plans to a total dose (TD) of 45 Gy were generated. For the def-group, 4 plans were generated: a 3D-CRT and an IMRT plan to a TD of 56.4 Gy, a SIB-IMRT plan to a TD of 56 Gy, and a SIB-IMRT with dose escalation (SIB-IMRT-esc): TD of 67.2 Gy. Mean dose and dose-volume histograms were compared using Student's t-test. IMRT significantly (all p < 0.05) reduced the D{sub mean}, V30, and V40 for all OAR in the adjuvant setting. The V45 was also significantly reduced for all OAR except the bladder. For patients treated in the def-group, all IMRT techniques significantly reduced the D{sub mean}, V40, and V45 for all OAR. The mean femur doses with SIB-IMRT and SIB-IMRT-esc were 47% and 49% lower compared with 3D-CRT. SIB-IMRT-esc reduced the doses to the OAR compared with seq-3D-CRT but increased the D{sub max.} for the small bowel, rectum, and bladder. IMRT reduces the dose to the OAR compared with 3D-CRT in patients with vulvar cancer receiving irradiation to a volume covering the vulvar region and nodal areas without compromising the dosimetric coverage of the target volume. IMRT for vulvar cancer is feasible and an attractive option for dose escalation studies.

  12. CT radiation dose and iterative reconstruction techniques

    National Research Council Canada - National Science Library

    Padole, Atul; Ali Khawaja, Ranish Deedar; Kalra, Mannudeep K; Singh, Sarabjeet

    2015-01-01

    .... CT image quality is dependent on the selected image reconstruction algorithm. 3. Iterative reconstruction algorithms have reemerged with the potential of radiation dose optimization by lowering image noise. 4...

  13. Effective dose: a radiation protection quantity

    CERN Document Server

    Menzel, H G

    2012-01-01

    Modern radiation protection is based on the principles of justification, limitation, and optimisation. Assessment of radiation risks for individuals or groups of individuals is, however, not a primary objective of radiological protection. The implementation of the principles of limitation and optimisation requires an appropriate quantification of radiation exposure. The International Commission on Radiological Protection (ICRP) has introduced effective dose as the principal radiological protection quantity to be used for setting and controlling dose limits for stochastic effects in the regulatory context, and for the practical implementation of the optimisation principle. Effective dose is the tissue weighted sum of radiation weighted organ and tissue doses of a reference person from exposure to external irradiations and internal emitters. The specific normalised values of tissue weighting factors are defined by ICRP for individual tissues, and used as an approximate age- and sex-averaged representation of th...

  14. [Searching Radiation Countermeasures using the Model of Prolonged Irradiation of Mice with Low Dose Rate and Evaluation of Their Influence on Heat Shock Protein Genes Expression].

    Science.gov (United States)

    Rozhdestvensky, L M; Mikhailov, V F; Schlyakova, T G; Shagirova, J M; Shchegoleva, R A; Raeva, N F; Lisina, N I; Shulenina, L V; Zorin, V V; Pchelka, A V; Trubitsina, K Y

    2015-01-01

    Different radiomodificators (cytokine betaleukine, antioxidant phenoxan, antigipoksant limontar and nucleoside riboxin) were investigated on mice for evaluating their radiation protective capacity against prolonged (21 h) exposure at a dose of 12.6 Gy at a low dose rate of 10 mGy/min. Bone marrow cellularity and endogenic CFUs were used as evaluation criteria 9 days after exposure. Simultaneously, expression of the heat shock proteins of 25, 70 and 90 kDa in unexposed mice bone marrow was studied 2, 24 and 48 h after injections. Betaleukine only had a positive significant effect in both tests in the variants of 50 mcg/kg and 3 mcg/kg when administered 2 h and 22 h before exposure, correspondingly. Effects of betaleukine HSPs on expression were both stimulating and inhibiting, that was in contradiction with a constant positive effect in 5 experiments on exposed mice for each betaleukine variant. It argues against the vital role of HSPs in the betaleukine antiradiation effect. In 2 experiments with high temperatures betaleukine administered at a dose of 50 mcg/kg evoked a very high HSP-70 gene expression after 24 h, and mice exposed to irradiation at that time in a parallel experiment showed an increased radiation effect. It corresponds to the idea that HSPs serve a stress indicator.

  15. Evaluation of occupational radiation dose in nuclear medicine: radiopharmaceutical administration to scintiscanning exams of myocardial perfusion; Avaliacao da dose de radiacao ocupacional em medicina nuclear: administracao de radiofarmacos em exames de cintilografria de perfusao miocardica

    Energy Technology Data Exchange (ETDEWEB)

    Komatsu, Cassio V., E-mail: cassiok@yahoo.com [Medicina Nuclear do Triangulo (MNT), Uberlandia, MG (Brazil); Michelin, Charlie A.; Jakubiak, Rosangela R., E-mail: charlie@utfpr.edu.br, E-mail: requi@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Lemes, Alyne O.; Silva, Juliana L.M., E-mail: alyne275@gmail.com, E-mail: jujumontesdocinho@gmail.com [Faculdade do Trabalho (FATRA), Uberlandia, MG (Brazil)

    2013-11-01

    In nuclear medicine, workers directly involved in exams are constantly exposed to ionizing radiation. The procedure for administration of the radiopharmaceutical to the patient is one of the most critical times of exposure. In tests of myocardial perfusion scintigraphy (MPS) administration of radiopharmaceutical repeats the steps of rest and cardiac stress. In this study, we used a Geiger -Mueller detector for measuring occupational radiation doses for during the administration of technetium- {sup 99m}- sestamibi in MPS tests. In the evaluation, discriminated the stages of examination and related professional experience time to doses measures at home. It were followed 110 procedures at home (55 conducted by professionals with over 5 years experience and 55 conducted by professionals with less than 1 year of experience) and 55 effort procedures. The results showed that the rest of the procedure time and dose are related to the experience of the worker. More experienced workers were faster (mean: 43 {+-} 16 vs 67 {+-} 25 seconds / procedure), and therefore received lower doses (mean 0.57 {+-} 0.16 versus 0.80 {+-} 0.24 {mu}Sv / procedure), both with statistical significance (p <0.001). In step effort, there were procedures lasting longer (mean: 19 {+-} 2 minutes / procedure), which resulted in higher doses (mean 3.0 {+-} 0.6 {mu}Sv / procedure)

  16. Dose mapping for documentation of radiation sterilization

    DEFF Research Database (Denmark)

    Miller, A.

    1999-01-01

    The radiation sterilization standards EN 552 and ISO 11137 require that dose mapping in real or simulated product be carried in connection with the process qualification. This paper reviews the recommendations given in the standards and discusses the difficulties and limitations of practical dose...

  17. Dosimetric verification and clinical evaluation of a new commercially available Monte Carlo-based dose algorithm for application in stereotactic body radiation therapy (SBRT) treatment planning

    Science.gov (United States)

    Fragoso, Margarida; Wen, Ning; Kumar, Sanath; Liu, Dezhi; Ryu, Samuel; Movsas, Benjamin; Munther, Ajlouni; Chetty, Indrin J.

    2010-08-01

    Modern cancer treatment techniques, such as intensity-modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT), have greatly increased the demand for more accurate treatment planning (structure definition, dose calculation, etc) and dose delivery. The ability to use fast and accurate Monte Carlo (MC)-based dose calculations within a commercial treatment planning system (TPS) in the clinical setting is now becoming more of a reality. This study describes the dosimetric verification and initial clinical evaluation of a new commercial MC-based photon beam dose calculation algorithm, within the iPlan v.4.1 TPS (BrainLAB AG, Feldkirchen, Germany). Experimental verification of the MC photon beam model was performed with film and ionization chambers in water phantoms and in heterogeneous solid-water slabs containing bone and lung-equivalent materials for a 6 MV photon beam from a Novalis (BrainLAB) linear accelerator (linac) with a micro-multileaf collimator (m3 MLC). The agreement between calculated and measured dose distributions in the water phantom verification tests was, on average, within 2%/1 mm (high dose/high gradient) and was within ±4%/2 mm in the heterogeneous slab geometries. Example treatment plans in the lung show significant differences between the MC and one-dimensional pencil beam (PB) algorithms within iPlan, especially for small lesions in the lung, where electronic disequilibrium effects are emphasized. Other user-specific features in the iPlan system, such as options to select dose to water or dose to medium, and the mean variance level, have been investigated. Timing results for typical lung treatment plans show the total computation time (including that for processing and I/O) to be less than 10 min for 1-2% mean variance (running on a single PC with 8 Intel Xeon X5355 CPUs, 2.66 GHz). Overall, the iPlan MC algorithm is demonstrated to be an accurate and efficient dose algorithm, incorporating robust tools for MC

  18. Low kilovoltage peak (kVp) with an adaptive statistical iterative reconstruction algorithm in computed tomography urography: evaluation of image quality and radiation dose.

    Science.gov (United States)

    Zhou, Zhiguo; Chen, Haixi; Wei, Wei; Zhou, Shanghui; Xu, Jingbo; Wang, Xifu; Wang, Qingguo; Zhang, Guixiang; Zhang, Zhuoli; Zheng, Linfeng

    2016-01-01

    The purpose of this study was to evaluate the image quality and radiation dose in computed tomography urography (CTU) images acquired with a low kilovoltage peak (kVp) in combination with an adaptive statistical iterative reconstruction (ASiR) algorithm. A total of 45 subjects (18 women, 27 men) who underwent CTU with kV assist software for automatic selection of the optimal kVp were included and divided into two groups (A and B) based on the kVp and image reconstruction algorithm: group A consisted of patients who underwent CTU with a 80 or 100 kVp and whose images were reconstructed with the 50% ASiR algorithm (n=32); group B consisted of patients who underwent CTU with a 120 kVp and whose images were reconstructed with the filtered back projection (FBP) algorithm (n=13). The images were separately reconstructed with volume rendering (VR) and maximum intensity projection (MIP). Finally, the image quality was evaluated using an image score, CT attenuation, image noise, the contrast-to-noise ratio (CNR) of the renal pelvis-to-abdominal visceral fat and the signal-to-noise ratio (SNR) of the renal pelvis. The radiation dose was assessed using volume CT dose index (CTDIvol), dose-length product (DLP) and effective dose (ED). For groups A and B, the subjective image scores for the VR reconstruction images were 3.9±0.4 and 3.8±0.4, respectively, while those for the MIP reconstruction images were 3.8±0.4 and 3.6±0.6, respectively. No significant difference was found (p>0.05) between the two groups' image scores for either the VR or MIP reconstruction images. Additionally, the inter-reviewer image scores did not significantly differ (p>0.05). The mean attenuation of the bilateral renal pelvis in group A was significantly higher than that in group B (271.4±57.6 vs. 221.8±35.3 HU, preconstruction exhibit sufficient image quality and facilitate up to a 44% radiation dose reduction.

  19. Radiation doses in chest, abdomen and pelvis CT procedures.

    Science.gov (United States)

    Manssor, E; Abuderman, A; Osman, S; Alenezi, S B; Almehemeid, S; Babikir, E; Alkhorayef, M; Sulieman, A

    2015-07-01

    Computed tomography (CT) scanning is recognised as a high-radiation dose modality and estimated to be 17 % of the radiological procedure and responsible for 70 % of medical radiation exposure. Although diagnostic X rays provide great benefits, their use involves some risk for developing cancer. The objectives of this study are to estimate radiation doses during chest, abdomen and pelvis CT. A total of 51 patients were examined for the evaluation of metastasis of a diagnosed primary tumour during 4 months. A calibrated CT machine from Siemens 64 slice was used. The mean age was 48.0 ± 18.6 y. The mean patient weight was 73.8 ± 16.1 kg. The mean dose-length product was 1493.8 ± 392.1 mGy cm, Volume CT dose index (CTDI vol) was 22.94 ± 5.64 mGy and the mean effective dose was 22.4 ± 5.9 mSv per procedure. The radiation dose per procedure was higher as compared with previous studies. Therefore, the optimisation of patient's radiation doses is required in order to reduce the radiation risk. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Low-dose radiation exposure and carcinogenesis

    National Research Council Canada - National Science Library

    Suzuki, Keiji; Yamashita, Shunichi

    2012-01-01

    .... Epidemiological studies have demonstrated the dose-response relationships for cancer induction and quantitative evaluations of cancer risk following exposure to moderate to high doses of low-linear...

  1. Radiation Dose Estimation by Automated Cytogenetic Biodosimetry.

    Science.gov (United States)

    Rogan, Peter K; Li, Yanxin; Wilkins, Ruth C; Flegal, Farrah N; Knoll, Joan H M

    2016-12-01

    The dose from ionizing radiation exposure can be interpolated from a calibration curve fit to the frequency of dicentric chromosomes (DCs) at multiple doses. As DC counts are manually determined, there is an acute need for accurate, fully automated biodosimetry calibration curve generation and analysis of exposed samples. Software, the Automated Dicentric Chromosome Identifier (ADCI), is presented which detects and discriminates DCs from monocentric chromosomes, computes biodosimetry calibration curves and estimates radiation dose. Images of metaphase cells from samples, exposed at 1.4-3.4 Gy, that had been manually scored by two reference laboratories were reanalyzed with ADCI. This resulted in estimated exposures within 0.4-1.1 Gy of the physical dose. Therefore, ADCI can determine radiation dose with accuracies comparable to standard triage biodosimetry. Calibration curves were generated from metaphase images in ~10 h, and dose estimations required ~0.8 h per 500 image sample. Running multiple instances of ADCI may be an effective response to a mass casualty radiation event. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Evaluation of surface radiation dose to the thyroid gland and the gonads during routine full-mouth intraoral periapical and maxillary occlusal radiography.

    Science.gov (United States)

    Sheikh, Soheyl; Bhoweer, Anil Kumar; Arya, Smriti; Arora, Gagandeep

    2010-04-01

    The quantitative aspects of radiation doses to critical organs can help the dental professionals to take the necessary radiation protective measures as deemed necessary and can help the general public to allay radiation exposure fear in dental radiography, if any. Our study determines the surface radiation dose to thyroid and gonads in full-mouth intraoral periapical (IOPA) and maxillary occlusal radiography. A total number of 120 subjects participated in the study. The surface radiation dose was estimated to the thyroid gland and the gonads in full-mouth IOPA radiography using 10 IOPA (E speed films) and in maxillary occlusal radiography. The measurements were calculated using a digital pocket dosimeter (PD-4507). The average dose at the thyroid gland level during full-mouth intraoral and maxillary occlusal radiography was estimated to be 10.93 mRads (1.093 × 10(-2) mGy) and 0.4 mRads (4.0 × 10(-2) mGy), respectively. The average surface radiation dose at the gonadal region during a full mouth intraoral and maxillary occlusal radiography was estimated to be 1.5 mRads (1.5 × 10(-2) mGy) and 0.15 mRads (1.5 × 10(-3) mGy), respectively. Our results suggest that although the radiation exposure doses to critical organs namely thyroid and gonads is within the safe limits still precautionary measures for these organs are advocated.

  3. Evaluation of doses from radiodiagnostic procedures performed in veterinary medicine and assessing of the doses of secondary radiation in the medical staff and animal owners; Avaliacao das doses resultantes de procedimentos radiodiagnosticos realizados em medicina veterinaria e avaliacao das doses secundarias de radiacao espalhada no corpo clinico e nos proprietarios dos animais

    Energy Technology Data Exchange (ETDEWEB)

    Veneziani, Glauco Rogerio

    2012-07-01

    The primary goal in veterinary radiography is to produce radiographs of diagnostic quality on the first attempt. This goal serves three purposes: (1) to decrease radiation exposure to the patient and veterinary personnel; (2) to decrease the cost of the study for the client; and (3) to produce diagnostic data for rapid interpretation and treatment of the patient. This work aimed to determine the doses in dogs submitted to chest and abdomen X rays using the technique of thermoluminescence (TL) dosimetry. The radiation doses were assessed using thermoluminescent dosimeters of calcium sulphate doped with dysprosium (CaSO{sub 4}:Dy) and lithium fluoride doped with magnesium and titanium (LiF:Mg,Ti). The obtained results indicate that is extremely important the assessment of radiation doses involved in veterinary diagnostic radiology procedures, to evaluate the delivered doses to the animals, to be used as a parameter in the individual monitoring of pet's owners, who assist the animal positioning, and to protect occupationally exposed workers at the Veterinary Radiology Clinics. (author)

  4. SU-C-12A-03: The Impact of Contrast Medium On Radiation Dose in CT: A Systematic Evaluation Across 58 Patient Models

    Energy Technology Data Exchange (ETDEWEB)

    Sahbaee, P [NC State University, Raleigh, NC (United States); Samei, E [Duke University Medical Center, Durham, NC (United States); Segars, W [Duke University, Durham, NC (United States)

    2014-06-01

    Purpose: To assess the effect of contrast medium on radiation dose as a function of time via Monte Carlo simulation from the liver CT scan across a library of 5D XCAT models Methods: A validated Monte Carlo simulation package (PENELOPE) was employed to model a CT system (LightSpeed 64 VCT, GE Healthcare). The radiation dose was estimated from a common abdomen CT examination. The dose estimation was performed on a library of adult extended cardiac-torso (5D XCAT) phantoms (35 male, 23 female, mean age 51.5 years, mean weight 80.2 kg). The 5D XCAT models were created based on patient-specific iodine concentration-time results from our computational contrast medium propagation model for different intravenous injection protocols. To enable a dynamic estimation of radiation dose, each organ in the model was assigned to its own time-concentration curve via the PENELOPE package, material.exe. Using the Monte Carlo, for each scan time point after the injection, 80 million photons were initiated and tracked through the phantoms. Finally, the dose to the liver was tallied from the deposited energy. Results: Monte Carlo simulation results of radiation dose delivered to the liver from the XCAT models indicated up to 30% increase in dose for different time after the administration of contrast medium. Conclusion: The contrast enhancement is employed in over 60% of imaging modalities, which not only remarkably affects the CT image quality, but also increases the radiation dose by as much as 70%. The postinjection multiple acquisition in several enhanced CT protocols, makes the radiation dose increment through the use of contrast medium, an inevitable factor in optimization of these protocols. The relationship between radiation dose and injected contrast medium as a function of time studied in this work allows optimization of contrast administration for vulnerable individuals.

  5. Epigenomic Adaptation to Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gould, Michael N. [Univ. of Wisconsin, Madison, WI (United States)

    2015-06-30

    The overall hypothesis of this grant application is that the adaptive responses elicited by low dose ionizing radiation (LDIR) result in part from heritable DNA methylation changes in the epigenome. In the final budget period at the University of Wisconsin-Madison, we will specifically address this hypothesis by determining if the epigenetically labile, differentially methylated regions (DMRs) that regulate parental-specific expression of imprinted genes are deregulated in agouti mice by low dose radiation exposure during gestation. This information is particularly important to ascertain given the 1) increased human exposure to medical sources of radiation; 2) increased number of people predicted to live and work in space; and 3) enhanced citizen concern about radiation exposure from nuclear power plant accidents and terrorist ‘dirty bombs.’

  6. Optimization of Z-axis automatic exposure control for multidetector row CT evaluation of neck and comparison with fixed tube current technique for image quality and radiation dose.

    Science.gov (United States)

    Namasivayam, S; Kalra, M K; Pottala, K M; Waldrop, S M; Hudgins, P A

    2006-01-01

    Z-axis automatic exposure control (AEC) technique automatically adjusts tube current based on size of body region scanned. The purpose of the current study was to compare diagnostic acceptability, noise, and radiation exposure of multidetector row CT (MDCT) of neck performed with z-axis AEC and with fixed current. Two study groups of 26 patients each underwent MDCT of neck using z-axis AEC with 8 noise index (NI), 150-440 mA, and 10 NI, 75-440 mA, respectively. A control group consisting of another 26 patients underwent MDCT of neck with fixed-current technique (300 mA). Objective noise and mean tube current-time products (mA . s) were recorded. Two radiologists evaluated images for diagnostic acceptability and subjective noise on a 5-point scale. All CT examinations of study and control groups were diagnostically acceptable, though objective noise was significantly more with z-axis AEC (shoulder: NI 8, 20.6 +/- 6.2 HU; NI 10, 22.2 +/- 4.6 HU) than with fixed current (16.2 +/- 6 HU) (P = .01). There was no significant difference between AEC and fixed current in diagnostic acceptability and subjective noise (P = .22-.42). AEC resulted in significant radiation dose reduction (NI 8, 186.3 +/- 20.5 mA . s; NI 10, 158.1 +/- 21.2 mA x s), compared with fixed current (235 +/- 21.8 mA x s). Z-axis AEC resulted in similar subjective noise and diagnostic acceptability, with radiation dose reduction of 21% for NI of 8 and 33% for NI of 10, respectively, for MDCT evaluation of neck, compared with those of fixed current technique.

  7. 10 CFR 20.1004 - Units of radiation dose.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy... Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are: Gray (Gy) is the SI unit of absorbed dose. One gray is equal to an absorbed dose of 1 Joule/kilogram (100...

  8. Evaluation of image quality and radiation dose at prospective ECG-triggered axial 256-slice multi-detector CT in infants with congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Mei-ping; Liang, Chang-hong; Zhao, Zhen-jun; Liu, Hui; Li, Jing-lei; Zhang, Jin-e; Cui, Yan-hai; Yang, Lin; Liu, Qi-shun [Guangdong Academy of Medical Sciences, Guangdong General Hospital, Department of Radiology, Guangzhou (China); Ivanc, Thomas B.; Vembar, Mani [Philips Healthcare, CT Clinical Science, Highland Heights, OH (United States)

    2011-07-15

    There are a limited number of reports on the technical and clinical feasibility of prospective electrocardiogram (ECG)-gated multi-detector computed tomography (MDCT) in infants with congenital heart disease (CHD). To evaluate image quality and radiation dose at weight-based low-dose prospectively gated 256-slice MDCT angiography in infants with CHD. From November 2009 to February 2010, 64 consecutive infants with CHD referred for pre-operative or post-operative CT were included. All were scanned on a 256-slice MDCT system utilizing a low-dose protocol (80 kVp and 60-120 mAs depending on weight: 60 mAs for {<=}3 kg, 80 mAs for 3.1-6 kg, 100 mAs for 6.1-10 kg, 120 mAs for 10.1-15 kg). No serious adverse events were recorded. A total of 174 cardiac deformities, confirmed by surgery or heart catheterization, were studied. The sensitivity of MDCT for cardiac deformities was 97.1%; specificity, 99.4%; accuracy, 95.9%. The mean heart rate during scan was 136.7 {+-} 14.9/min (range, 91-160) with a corresponding heart rate variability of 2.8 {+-} 2.2/min (range, 0-8). Mean scan length was 115.3 {+-} 11.7 mm (range, 93.6-143.3). Mean volume CT dose index, mean dose-length product and effective dose were 2.1 {+-} 0.4 mGy (range, 1.5-2.8), 24.7 {+-} 5.9 mGy.cm (range, 14.7-35.8) and 1.6 {+-} 0.3 mSv (range, 1.1-2.5), respectively. Diagnostic-quality images were achieved in all cases. Satisfactory diagnostic quality for visualization of all/proximal/distal coronary artery segments was achieved in 88.4/98.8/80.0% of the scans. Low-dose prospectively gated axial 256-slice CT angiography is a valuable tool in the routine clinical evaluation of infants with CHD, providing a comprehensive three-dimensional evaluation of the cardiac anatomy, including the coronary arteries. (orig.)

  9. Radiation Doses to Skin from Dermal Contamination

    Science.gov (United States)

    2010-10-01

    Doses to Skin From Dermal Contamination HDTRA1-07-C-0015 A. Iulian Apostoaei and David C. Kocher Prepared by: SENES Oak Ridge, Inc. Center for Risk...5a. CONTRACT NUMBER HDTRA1-07-C-0015 5b. GRANT NUMBER 4. TITLE AND SUBTITLE Radiation Doses to Skin from Dermal Contamination 5c... contamination due to a uniform deposition of airborne radioactive material in specific regions of the body. This methodology includes a model to estimate

  10. Radiation Leukemogenesis at Low Dose Rates

    Energy Technology Data Exchange (ETDEWEB)

    Weil, Michael; Ullrich, Robert

    2013-09-25

    The major goals of this program were to study the efficacy of low dose rate radiation exposures for the induction of acute myeloid leukemia (AML) and to characterize the leukemias that are caused by radiation exposures at low dose rate. An irradiator facility was designed and constructed that allows large numbers of mice to be irradiated at low dose rates for protracted periods (up to their life span). To the best of our knowledge this facility is unique in the US and it was subsequently used to study radioprotectors being developed for radiological defense (PLoS One. 7(3), e33044, 2012) and is currently being used to study the role of genetic background in susceptibility to radiation-induced lung cancer. One result of the irradiation was expected; low dose rate exposures are ineffective in inducing AML. However, another result was completely unexpected; the irradiated mice had a very high incidence of hepatocellular carcinoma (HCC), approximately 50%. It was unexpected because acute exposures are ineffective in increasing HCC incidence above background. This is a potential important finding for setting exposure limits because it supports the concept of an 'inverse dose rate effect' for some tumor types. That is, for the development of some tumor types low dose rate exposures carry greater risks than acute exposures.

  11. Radiation dose assessments for materials with elevated natural radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Markkanen, M.

    1995-11-01

    The report provides practical information needed for evaluating the radiation dose to the general public and workers caused by materials containing elevated levels of natural radionuclides. The report presents criteria, exposure scenarios and calculations used to assess dose with respect to the safety requirements set for construction materials in accordance with the Finnish Radiation Act. A method for calculating external gamma exposure from building materials is presented in detail. The results for most typical cases are given as specific dose rates in table form to enable doses to be assessed without computer calculation. A number of such dose assessments is presented, as is the corresponding computer code. Practical investigation levels for the radioactivity of materials are defined. (23 refs.).

  12. Radiation Biology Irradiator Dose Verification Survey.

    Science.gov (United States)

    Pedersen, Kurt H; Kunugi, Keith A; Hammer, Clifford G; Culberson, Wesley S; DeWerd, Larry A

    2016-02-01

    Interest in standardized dosimetry for radiobiological irradiators has expanded over the last decade. At a symposium held at NIST, "The Importance of Standardization of Dosimetry in Radiobiology", a set of 12 criteria necessary for adequate irradiation was developed by the authors. Here we report on our review of dosimetry methods from various peer-reviewed publications and found that none of them satisfied all 12 criteria set forth by the authors of the NIAD/NCI/NIST proceedings. The inadequate reporting of dosimetry methods in the literature raises questions regarding the accuracy of the dose delivered to animal test subjects and the resulting experimental results. For this reason, we investigated the level of accuracy of dose delivery in radiation biology studies. We performed an irradiator output verification study of 12 radiation biology laboratories (7 gamma and 5 X-ray units) using polymethyl methacrylate (PMMA) mouse phantoms and thermoluminescent dosimeters (TLDs) readouts at the University of Wisconsin Medical Radiation Research Center (UWMRRC). The laboratories housing each of these irradiators were asked to deliver specific doses to individual mouse phantoms. Simultaneously, mouse phantoms at the UWMRRC were irradiated with NIST-traceable reference beams representative of the subject laboratories' beam energies. The irradiated mouse phantoms were returned from the various institutions to the UWMRRC and the TLDs were processed, with their measured dose response compared to the known dose response of the calibration phantom TLDs. Of the five facilities using X-ray irradiators, only one delivered an output within 5% of the target dose. The dose differences for the other four X-ray irradiators ranged from 12 to 42%. These results indicate the potential need for standardization of dose determination and additional oversight of radiobiology investigations.

  13. Evaluation of low-dose proton beam radiation efficiency in MIA PaCa-2 pancreatic cancer cell line vitality and H2AX formation.

    Science.gov (United States)

    Liubavičiūtė, Aušra; Kraśko, Jan Aleksander; Mlynska, Agata; Lagzdina, Jelena; Sužiedėlis, Kęstutis; Pašukonienė, Vita

    2015-11-01

    The aim of this study was to evaluate the efficiency of proton beam irradiation in pancreatic cancer cell line MIA PaCa-2 and its role in the cell cycle, apoptosis, and formation of histone γH2AX in different reparation times (72-h follow-up). The MIA PaCa-2 pancreatic carcinoma cell line was irradiated with 1.6-Gy proton beam. After irradiation, cell viability was measured colorimetrically, and the cell cycle, apoptosis, and γH2AX expression were evaluated on a FACScan cytometer. Low-dose proton beam irradiation had an effect on the MIA PaCa-2 tumor cell line already 1h after exposure, but maximal lethality was reached after 72h postirradiation with a cell viability rate of 24%. The cell cycle went into partial G1/0 arrest, and was released after 72h. The expression of γH2AX was strong and its levels were significantly elevated as late as 48h post radiation. The apoptosis levels increased with post radiation incubation time to reach 79% after 72h. Our data demonstrate that low-doses proton beam irradiation had an effect on MIA PaCa-2 pancreatic carcinoma cell line. Full extent of irradiation had an impact only 24h postirradiation, triggering DNA arrested cell cycle in G1/0 phase. Formed DNA DSBs were found to be repaired via the NHEJ pathway mechanism within 72h. Unsuccessful repaired DSBs induced apoptotic cell death. After 72h reparation processes were completed, and cell cycle was released from arrest in G1/0 phase. Copyright © 2015 Lithuanian University of Health Sciences. Production and hosting by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  14. Effect of real-time radiation dose feedback on pediatric interventional radiology staff radiation exposure.

    Science.gov (United States)

    Racadio, John; Nachabe, Rami; Carelsen, Bart; Racadio, Judy; Hilvert, Nicole; Johnson, Neil; Kukreja, Kamlesh; Patel, Manish

    2014-01-01

    To measure and compare individual staff radiation dose levels during interventional radiologic (IR) procedures with and without real-time feedback to evaluate whether it has any impact on staff radiation dose. A prospective trial was performed in which individuals filling five different staff roles wore radiation dosimeters during all IR procedures during two phases: a 12-week "closed" phase (measurements recorded but display was off, so no feedback was provided) and a 17-week "open" phase (display was on and provided real-time feedback). Radiation dose rates were recorded and compared by Mann-Whitney U test. There was no significant difference in median procedure time, fluoroscopy time, or patient dose (dose-area product normalized to fluoroscopy time) between the two phases. Overall, the median staff dose was lower in the open phase (0.56 µSv/min of fluoroscopy time) than in the closed phase (3.01 µSv/min; P staff can significantly reduce radiation exposure to the primary operator, most likely by increasing staff compliance with use of radiation protection equipment and dose reduction techniques. Copyright © 2014. Published by Elsevier Inc.

  15. Evaluation of surface radiation dose to the thyroid gland and the gonads during routine full-mouth intraoral periapical and maxillary occlusal radiography

    Directory of Open Access Journals (Sweden)

    Soheyl Sheikh

    2010-01-01

    Full Text Available Aim: The quantitative aspects of radiation doses to critical organs can help the dental professionals to take the necessary radiation protective measures as deemed necessary and can help the general public to allay radiation exposure fear in dental radiography, if any. Our study determines the surface radiation dose to thyroid and gonads in full-mouth intraoral periapical (IOPA and maxillary occlusal radiography.Materials and Methods: A total number of 120 subjects participated in the study. The surface radiation dose was estimated to the thyroid gland and the gonads in full-mouth IOPA radiography using 10 IOPA (E speed films and in maxillary occlusal radiography. The measurements were calculated using a digital pocket dosimeter (PD-4507.Results: The average dose at the thyroid gland level during full-mouth intraoral and maxillary occlusal radiography was estimated to be 10.93 mRads (1.093 Χ 10 -2 mGy and 0.4 mRads (4.0 Χ 10 -2 mGy, respectively. The average surface radiation dose at the gonadal region during a full mouth intraoral and maxillary occlusal radiography was estimated to be 1.5 mRads (1.5 Χ 10 -2 mGy and 0.15 mRads (1.5 Χ 10 -3 mGy, respectively. Conclusion: Our results suggest that although the radiation exposure doses to critical organs namely thyroid and gonads is within the safe limits still precautionary measures for these organs are advocated.

  16. Radiation Dose Optimization For Critical Organs

    Science.gov (United States)

    Khodadadegan, Yasaman

    Ionizing radiation used in the patient diagnosis or therapy has negative effects on the patient body in short term and long term depending on the amount of exposure. More than 700,000 examinations are everyday performed on Interventional Radiology modalities, however; there is no patient-centric information available to the patient or the Quality Assurance for the amount of organ dose received. In this study, we are exploring the methodologies to systematically reduce the absorbed radiation dose in the Fluoroscopically Guided Interventional Radiology procedures. In the first part of this study, we developed a mathematical model which determines a set of geometry settings for the equipment and a level for the energy during a patient exam. The goal is to minimize the amount of absorbed dose in the critical organs while maintaining image quality required for the diagnosis. The model is a large-scale mixed integer program. We performed polyhedral analysis and derived several sets of strong inequalities to improve the computational speed and quality of the solution. Results present the amount of absorbed dose in the critical organ can be reduced up to 99% for a specific set of angles. In the second part, we apply an approximate gradient method to simultaneously optimize angle and table location while minimizing dose in the critical organs with respect to the image quality. In each iteration, we solve a sub-problem as a MIP to determine the radiation field size and corresponding X-ray tube energy. In the computational experiments, results show further reduction (up to 80%) of the absorbed dose in compare with previous method. Last, there are uncertainties in the medical procedures resulting imprecision of the absorbed dose. We propose a robust formulation to hedge from the worst case absorbed dose while ensuring feasibility. In this part, we investigate a robust approach for the organ motions within a radiology procedure. We minimize the absorbed dose for the critical

  17. Absorbed radiation dose on LHC interconnects

    CERN Document Server

    Versaci, R; Vlachoudis, V; CERN. Geneva. ATS Department

    2011-01-01

    Here we present the results of our FLUKA simulations devoted to the evaluation of the peak dose absorbed by the busbar insulator in the LHC Interaction Region 7 interconnects. The peak dose absorbed by the cold magnet coils are also presented.

  18. Agriculture-related radiation dose calculations

    Energy Technology Data Exchange (ETDEWEB)

    Furr, J.M.; Mayberry, J.J.; Waite, D.A.

    1987-10-01

    Estimates of radiation dose to the public must be made at each stage in the identification and qualification process leading to siting a high-level nuclear waste repository. Specifically considering the ingestion pathway, this paper examines questions of reliability and adequacy of dose calculations in relation to five stages of data availability (geologic province, region, area, location, and mass balance) and three methods of calculation (population, population/food production, and food production driven). Calculations were done using the model PABLM with data for the Permian and Palo Duro Basins and the Deaf Smith County area. Extra effort expended in gathering agricultural data at succeeding environmental characterization levels does not appear justified, since dose estimates do not differ greatly; that effort would be better spent determining usage of food types that contribute most to the total dose; and that consumption rate and the air dispersion factor are critical to assessment of radiation dose via the ingestion pathway. 17 refs., 9 figs., 32 tabs.

  19. Radiation Dose and Image Quality of Low-dose Protocol in Chest CT: Comparison of Standard-dose Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Jeong [Occupational Lung Diseases Institute, KCOMWEL, Seoul (Korea, Republic of); Ahn, Bong Seon; Park, Young Sun [Department of Radiological Technology, Daejeon Health Science College, Daejeon (Korea, Republic of)

    2012-06-15

    The purpose of this study was to compare radiation dose and image quality between low-dose (LDP) and standard-dose protocol (SDP). LDP (120 kVp, 30 mAs, 2-mm thickness) and SDP (120 kVp, 180 mAs, 1.2-mm thickness) images obtained from 61 subjects were retrospectively evaluated at level of carina bifurcation, using multi-detector CT (Brilliance 16, Philips Medical Systems). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated at ascending aorta and infraspinatus muscle, from CT number and back-ground noise. Radiation dose from two protocols measured at 5-point using acrylic-phantom, and CT number and noise measured at 4-point using water-phantom. All statistical analysis were performed using SPSS 19.0 program. LDP images showed significantly more noise and a significantly lower SNR and CNR than did SDP images at ascending aorta and infraspinatus muscle. Noise, SNR and CNR were significantly correlated with body mass index (p<0.001). Radiation dose, SNR and CNR from phantom were significant differences between two protocols. LDP showed a significant reduction of radiation dose with a significant change in SNR and CNR compared with SDP. Therefore, exposure dose on LDP in clinical applications needs resetting highly more considering image quality.

  20. Low-dose Radiation Exposure and Carcinogenesis

    OpenAIRE

    Suzuki, Keiji; Yamashita, Shunichi

    2012-01-01

    Absorption of energy from ionizing radiation by the genetic material in the cell leads to damage to DNA, which in turn leads to cell death, chromosome aberrations and gene mutations. While early or deterministic effects result from organ and tissue damage caused by cell killing, latter two are considered to be involved in the initial events that lead to the development of cancer. Epidemiological studies have demonstrated the dose-2013;response relationships for cancer induction and quantitati...

  1. Magnetic Resonance Image Guided Radiation Therapy for External Beam Accelerated Partial-Breast Irradiation: Evaluation of Delivered Dose and Intrafractional Cavity Motion

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, Sahaja; Fischer-Valuck, Benjamin W.; Mazur, Thomas R.; Curcuru, Austen; Sona, Karl; Kashani, Rojano; Green, Olga; Ochoa, Laura; Mutic, Sasa; Zoberi, Imran; Li, H. Harold; Thomas, Maria A., E-mail: mthomas@radonc.wustl.edu

    2016-11-15

    Purpose: To use magnetic resonance image guided radiation therapy (MR-IGRT) for accelerated partial-breast irradiation (APBI) to (1) determine intrafractional motion of the breast surgical cavity; and (2) assess delivered dose versus planned dose. Methods and Materials: Thirty women with breast cancer (stages 0-I) who underwent breast-conserving surgery were enrolled in a prospective registry evaluating APBI using a 0.35-T MR-IGRT system. Clinical target volume was defined as the surgical cavity plus a 1-cm margin (excluding chest wall, pectoral muscles, and 5 mm from skin). No additional margin was added for the planning target volume (PTV). A volumetric MR image was acquired before each fraction, and patients were set up to the surgical cavity as visualized on MR imaging. To determine the delivered dose for each fraction, the electron density map and contours from the computed tomography simulation were transferred to the pretreatment MR image via rigid registration. Intrafractional motion of the surgical cavity was determined by applying a tracking algorithm to the cavity contour as visualized on cine MR. Results: Median PTV volume was reduced by 52% when using no PTV margin compared with a 1-cm PTV margin used conventionally. The mean (± standard deviation) difference between planned and delivered dose to the PTV (V95) was 0.6% ± 0.1%. The mean cavity displacement in the anterior–posterior and superior–inferior directions was 0.6 ± 0.4 mm and 0.6 ± 0.3 mm, respectively. The mean margin required for at least 90% of the cavity to be contained by the margin for 90% of the time was 0.7 mm (5th-95th percentile: 0-2.7 mm). Conclusion: Minimal intrafractional motion was observed, and the mean difference between planned and delivered dose was less than 1%. Assessment of efficacy and cosmesis of this MR-guided APBI approach is under way.

  2. The evaluation of contralateral breast's dose and shielding efficiency by breast size about breast implant patient for radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Wook; Woo, Heon; Jeong, Hyeon Hak; Kim, Kyeong Ah; Kim, Chan Yong; Yoo, Suk Hyun [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-12-15

    To evaluate the dose on a contralateral breast and the usefulness of shielding according to the distance between the contralateral breast and the side of the beam by breast size when patients who got breast implant receive radiation therapy. We equipped 200 cc, 300 cc, 400 cc, and 500 cc breast model on the human phantom (Rando-phantom), acquired CT images (philips 16channel, Netherlands) and established the radiation treatment plan, 180 cGy per day on the left breast (EclipseTM ver10.0.42, Varian Medical Systems, USA) by size. We set up each points, A, B, C, and D on the right(contralateral) breast model for measurement by size and by the distance from the beam and attached MOSFET at each points. The 6 MV, 10 MV and 15 MV X-ray were irradiated to the left(target) breast model and we measured exposure dose of contralateral breast model using MOSFET. Also, at the same condition, we acquired the dose value after shielding using only Pb 2 mm and bolus 3 mm under the Pb 2 mm together. As the breast model is bigger from 200 cc to 500 cc, The surface of the contralateral breast is closer to the beam. As a result, from 200 cc to 500 cc, on 180 cGy basis, the measurement value of the scattered ray inclined by 3.22-4.17% at A point, 4.06-6.22% at B point, 0.4-0.5% at C point, and was under 0.4% at D point. As the X-ray energy is higher, from 6 MV to 15 MV, on 180 cGy basis, the measurement value of the scattered ray inclined by 4.06-5% at A point, 2.85-4.94% at B point, 0.74-1.65% at C point, and was under 0.4% at D point. As using Pb 2 mm for shield, scattered ray declined by average 9.74% at A and B point, 2.8% at C point, and is under 1% at D point. As using Pb 2 mm and bolus together for shield, scattered ray declined by average 9.76% at A and B point, 2.2% at C point, and is under 1% at D point. Commonly, in case of patients who got breast implant, there is a distance difference by breast size between the contralateral breast and the side of beam. As the distance is

  3. A dose error evaluation study for 4D dose calculations

    Science.gov (United States)

    Milz, Stefan; Wilkens, Jan J.; Ullrich, Wolfgang

    2014-10-01

    Previous studies have shown that respiration induced motion is not negligible for Stereotactic Body Radiation Therapy. The intrafractional breathing induced motion influences the delivered dose distribution on the underlying patient geometry such as the lung or the abdomen. If a static geometry is used, a planning process for these indications does not represent the entire dynamic process. The quality of a full 4D dose calculation approach depends on the dose coordinate transformation process between deformable geometries. This article provides an evaluation study that introduces an advanced method to verify the quality of numerical dose transformation generated by four different algorithms. The used transformation metric value is based on the deviation of the dose mass histogram (DMH) and the mean dose throughout dose transformation. The study compares the results of four algorithms. In general, two elementary approaches are used: dose mapping and energy transformation. Dose interpolation (DIM) and an advanced concept, so called divergent dose mapping model (dDMM), are used for dose mapping. The algorithms are compared to the basic energy transformation model (bETM) and the energy mass congruent mapping (EMCM). For evaluation 900 small sample regions of interest (ROI) are generated inside an exemplary lung geometry (4DCT). A homogeneous fluence distribution is assumed for dose calculation inside the ROIs. The dose transformations are performed with the four different algorithms. The study investigates the DMH-metric and the mean dose metric for different scenarios (voxel sizes: 8 mm, 4 mm, 2 mm, 1 mm 9 different breathing phases). dDMM achieves the best transformation accuracy in all measured test cases with 3-5% lower errors than the other models. The results of dDMM are reasonable and most efficient in this study, although the model is simple and easy to implement. The EMCM model also achieved suitable results, but the approach requires a more complex

  4. The evaluation of the radioprotective effect of chyavanaprasha (an ayurvedic rasayana drug) in mice exposed to lethal dose of gamma-radiation: a preliminary study.

    Science.gov (United States)

    Jagetia, Ganesh Chandra; Baliga, Manjeshwar Shrinath

    2004-01-01

    The effect of various doses of 50% ethanolic extract of chyavanaprasha (an Ayurvedic rejuvenating herbal preparation) was studied on the survival of mice exposed to 10 Gy of gamma-radiation. Treatment with chyavanaprasha, consecutively for fi ve days before irradiation, delayed symptoms of radiation sickness and onset of mortality when compared with the non-drug treated irradiated controls. All doses of chyavanaprasha provided a significant protection against gastrointestinal (GI) death (death of animals within 10 days after exposure to radiation), however, highest protection against GI death was observed for 15 mg/kg chyavanaprasha. Chyavanaprasha also provided a significant protection against the bone marrow death after 10 to 40 mg/kg. However, the best protection was seen for 15 mg/kg, where the highest number of survivors was observed at the end of 30 days post-irradiation. The drug was non-toxic up to a dose of 6 g/kg b. wt., the highest drug dose that could be tested. Our study demonstrates that chyavanaprasha can provide good radioprotection at a very low non-toxic dose. Copyright 2004 John Wiley & Sons, Ltd.

  5. Low Dose Ionizing Radiation Modulates Immune Function

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Gregory A. [Loma Linda Univ., CA (United States)

    2016-01-12

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a “Th2 polarized” immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in the

  6. Ultraviolet radiation therapy and UVR dose models.

    Science.gov (United States)

    Grimes, David Robert

    2015-01-01

    Ultraviolet radiation (UVR) has been an effective treatment for a number of chronic skin disorders, and its ability to alleviate these conditions has been well documented. Although nonionizing, exposure to ultraviolet (UV) radiation is still damaging to deoxyribonucleic acid integrity, and has a number of unpleasant side effects ranging from erythema (sunburn) to carcinogenesis. As the conditions treated with this therapy tend to be chronic, exposures are repeated and can be high, increasing the lifetime probability of an adverse event or mutagenic effect. Despite the potential detrimental effects, quantitative ultraviolet dosimetry for phototherapy is an underdeveloped area and better dosimetry would allow clinicians to maximize biological effect whilst minimizing the repercussions of overexposure. This review gives a history and insight into the current state of UVR phototherapy, including an overview of biological effects of UVR, a discussion of UVR production, illness treated by this modality, cabin design and the clinical implementation of phototherapy, as well as clinical dose estimation techniques. Several dose models for ultraviolet phototherapy are also examined, and the need for an accurate computational dose estimation method in ultraviolet phototherapy is discussed.

  7. Reconstructive dosimetry and radiation doses evaluation of members of the public due to radiological accident in industrial radiography; Dosimetria reconstrutiva e avaliacao de dose de individuos do publico devido a acidente radiologico em radiografia industrial

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Camila Moreira Araujo de

    2016-07-01

    Radiological accidents have occurred mainly in the practices recognized as high risk radiological and classified by the IAEA as Categories 1 and 2, and highlighted the radiotherapy, industrial irradiators and industrial radiography. In Brazil, since there were five major cases in industrial radiography, which involved 7 radiation workers and 19 members of the public, causing localized radiation lesions on the hands and fingers. One of these accidents will be the focus of this work. In this accident, a {sup 192}Ir radioactive source was exposed for more than 8 hours in the workplace inside a company, exposing radiation workers, individuals of the public and people from the surrounding facilities, including children of a school. The radioactive source was also handled by a security worker causing severe radiation injuries in the hand and fingers. In this paper, the most relevant and used techniques of reconstructive dosimetry internationally are presented. To estimate the radiation doses received by exposed individuals in various scenarios of radiological accident in focus, the following computer codes were used: Visual Monte Carlo Dose Calculation (VMC), Virtual Environment for Radiological and Nuclear Accidents Simulation (AVSAR) and RADPRO Calculator. Through these codes some radiation doses were estimated, such as, 33.90 Gy in security worker's finger, 4.47 mSv in children in the school and 55 to 160 mSv for workers in the company during the whole day work. It is intended that this work will contribute to the improvement of dose reconstruction methodology for radiological accidents, having then more realist radiation doses. (author)

  8. In vitro cell culture lethal dose submitted to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Carolina S.; Rogero, Sizue O.; Rogero, Jose Roberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: carolina_sm@hotmail.com; Ikeda, Tamiko I.; Cruz, Aurea S. [Instituto Adolfo Lutz, Sao Paulo, SP (Brazil)

    2009-07-01

    The present study was designed to evaluate the in vitro effect of gamma radiation in cell culture of mouse connective tissue exposed to different doses of gamma radiation and under several conditions. The cell viability was analyzed by neutral red uptake methodology. This assay was developed for establish a methodology to be used in the future in the study of resveratrol radioprotection. Resveratrol (3,4',5- trihydroxystilbene), a phenolic phytoalexin that occurs naturally in some spermatophytes, such as grapevines, in response to injury as fungal infections and exposure to ultraviolet light. In the wines this compound is found at high levels and is considered one of the highest antioxidant constituents. The intense antioxidant potential of resveratrol provides many pharmacological activities including cardioprotection, chemoprevention and anti-tumor effects. Our results demonstrated that {sup 60}Co gamma radiation lethal dose (LD50) on NCTC clone 929 cells was about 340Gy. (author)

  9. Prenatal radiation exposure. Dose calculation; Praenatale Strahlenexposition. Dosisermittlung

    Energy Technology Data Exchange (ETDEWEB)

    Scharwaechter, C.; Schwartz, C.A.; Haage, P. [University Hospital Witten/Herdecke, Wuppertal (Germany). Dept. of Diagnostic and Interventional Radiology; Roeser, A. [University Hospital Witten/Herdecke, Wuppertal (Germany). Dept. of Radiotherapy and Radio-Oncology

    2015-05-15

    The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero X-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties.

  10. Radiation doses to neonates requiring intensive care

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, A. (Weston Park Hospital, Sheffield (UK)); Dellagrammaticas, H.D. (Sheffield Univ. (UK))

    1983-06-01

    Radiological investigations have become accepted as an important part of the range of facilities required to support severely ill newborn babies. Since the infants are so small, many of the examinations are virtually ''whole-body'' irradiations and it was thought that the total doses received might be appreciable. A group of such babies admitted to the Neonatal Intensive Care Unit in Sheffield over a six-month period have been studied. X-ray exposure factors used for each examination have been noted and total skin, gonad and bone marrow doses calculated, supplemented by measurements on phantoms. It is concluded that in most cases doses received are of the same order as those received over the same period from natural background radiation and probably less than those received from prenatal obstetric radiography, so that the additional risks from the diagnostic exposure are small. The highest doses are received in CT scans and barium examinations and it is recommended that the need for these should be carefully considered.

  11. Evaluation of the detriment associated with exposure at low doses and low dose rates in the radiation protection system; Evaluation du detriment associe a l'exposition aux faibles doses et faibles debits de dose dans le systeme de radioprotection

    Energy Technology Data Exchange (ETDEWEB)

    Vaillant, Ludovic; Schneider, Thierry [CEPN, 28, rue de la Redoute, 92260 Fontenay-aux-Roses (France)

    2012-03-15

    Questions about quantifying the radiological risk associated with exposure to ionising radiation have been debated repeatedly for a variety of exposure situations, including, among others, medical irradiation, discharges from nuclear facilities, transportation of radioactive waste, and potential nuclear accidents. This paper aims to shed light on the link between exposure and risk, focusing on the items that constitute the detriment associated with this exposure. The management of the risk associated with it relies on a cautious hypothesis of a linear no-threshold relation between exposure and risk of death or detriment. The International Commission on Radiological Protection (ICRP) published General Recommendations in 1966 that recognised this relation, but did not publish a quantification of the risk until 1977. The Commission introduced the concept of effective dose as a risk indicator that makes it possible to determine dose limits according to the risk associated with them. In 1990, the Commission proposed a revision of the quantification and construction of detriment. New limits, based on risk quantification and, for the first time, risk tolerability, were proposed. The optimisation of radiation protection - keeping radiation exposure as low as reasonably achievable in light of the economic and social context - became the key principle of the radiation protection system. The use of detriment makes it possible to use economic tools to guide the decision process for this optimisation - by assessing the monetary value of human life. This concept, widely used in health economics during the 1980's, has been criticised by many and must be used cautiously. ICRP published the latest quantifications of detriment in 2007. Detriment is thus an indicator that assesses the risk of death associated with exposure to ionising radiation for an average individual. Its construction relies on simplifying assumptions that are needed to implement a robust and effective

  12. Transatlantic Comparison of CT Radiation Doses in the Era of Radiation Dose-Tracking Software.

    Science.gov (United States)

    Parakh, Anushri; Euler, Andre; Szucs-Farkas, Zsolt; Schindera, Sebastian T

    2017-12-01

    The purpose of this study is to compare diagnostic reference levels from a local European CT dose registry, using radiation-tracking software from a large patient sample, with preexisting European and North American diagnostic reference levels. Data (n = 43,761 CT scans obtained over the course of 2 years) for the European local CT dose registry were obtained from eight CT scanners at six institutions. Means, medians, and interquartile ranges of volumetric CT dose index (CTDI vol ), dose-length product (DLP), size-specific dose estimate, and effective dose values for CT examinations of the head, paranasal sinuses, thorax, pulmonary angiogram, abdomen-pelvis, renal-colic, thorax-abdomen-pelvis, and thoracoabdominal angiogram were obtained using radiation-tracking software. Metrics from this registry were compared with diagnostic reference levels from Canada and California (published in 2015), the American College of Radiology (ACR) dose index registry (2015), and national diagnostic reference levels from local CT dose registries in Switzerland (2010), the United Kingdom (2011), and Portugal (2015). Our local registry had a lower 75th percentile CTDI vol for all protocols than did the individual internationally sourced data. Compared with our study, the ACR dose index registry had higher 75th percentile CTDI vol values by 55% for head, 240% for thorax, 28% for abdomen-pelvis, 42% for thorax-abdomen-pelvis, 128% for pulmonary angiogram, 138% for renal-colic, and 58% for paranasal sinus studies. Our local registry had lower diagnostic reference level values than did existing European and North American diagnostic reference levels. Automated radiation-tracking software could be used to establish and update existing diagnostic reference levels because they are capable of analyzing large datasets meaningfully.

  13. The development of wireless radiation dose monitoring using smart phone

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Woo; Jeong, Gyo Seong; Lee, Yun Jong [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Kim, Chong Yeal [Chonbuk National University, Jeonju (Korea, Republic of); Lim, Chai Wan [REMTECH, Seoul (Korea, Republic of)

    2016-11-15

    Radiation workers at a nuclear facility or radiation working area should hold personal dosimeters. some types of dosimeters have functions to generate audible or visible alarms to radiation workers. However, such devices used in radiation fields these days have no functions to communicate with other equipment or the responsible personnel. our project aims at the development of a remote wireless radiation dose monitoring system that can be utilized to monitor the radiation dose for radiation workers and to notify the radiation protection manager of the dose information in real time. We use a commercial survey meter for personal radiation measurement and a smart phone for a mobile wireless communication tool and a Beacon for position detection of radiation workers using Blue tooth communication. In this report, the developed wireless dose monitoring of cellular phone is introduced.

  14. Initial experience with adaptive iterative dose reduction 3D to reduce radiation dose in computed tomographic urography.

    Science.gov (United States)

    Juri, Hiroshi; Matsuki, Mitsuru; Itou, Yasushi; Inada, Yuki; Nakai, Go; Azuma, Haruhito; Narumi, Yoshifumi

    2013-01-01

    This study aimed to investigate the feasibility of low-dose computed tomographic (CT) urography with adaptive iterative dose reduction 3D (AIDR 3D). Thirty patients underwent routine-dose CT scans with filtered back projection and low-dose CT scans with AIDR 3D in the excretory phase of CT urography. Visual evaluations were performed with respect to internal image noises, sharpness, streak artifacts, and diagnostic acceptability. Quantitative measures of the image noise and radiation dose were also obtained. All results were compared on the basis of body mass index (BMI). At visual evaluations, streak artifacts in the urinary bladder were statistically weaker on low-dose CT than on routine-dose CT in the axial and coronal images (P urography with AIDR 3D allows 45% reduction of radiation dose without degenerating of the image quality in the excretory phase independently to a BMI.

  15. Dose reconstruction technique using non-rigid registration to evaluate spatial correspondence between high-dose region and late radiation toxicity: a case of tracheobronchial stenosis after external beam radiotherapy combined with endotracheal brachytherapy for tracheal cancer

    Directory of Open Access Journals (Sweden)

    Kazuma Kobayashi

    2016-04-01

    Full Text Available Purpose : Small organ subvolume irradiated by a high-dose has been emphasized to be associated with late complication after radiotherapy. Here, we demonstrate a potential use of surface-based, non-rigid registration to investigate how high-dose volume topographically correlates with the location of late radiation morbidity in a case of tracheobronchial radiation stenosis. Material and methods: An algorithm of point set registration was implemented to handle non-rigid registration between contour points on the organ surfaces. The framework estimated the global correspondence between the dose distribution and the varying anatomical structure. We applied it to an 80-year-old man who developed tracheobronchial stenosis 2 years after high-dose-rate endobronchial brachytherapy (HDR-EBT (24 Gy in 6 Gy fractions and external beam radiotherapy (EBRT (40 Gy in 2 Gy fractions for early-stage tracheal cancer. Results and conclusions : Based on the transformation function computed by the non-rigid registration, irradiated dose distribution was reconstructed on the surface of post-treatment tracheobronchial stenosis. For expressing the equivalent dose in a fractional dose of 2 Gy in HDR-EBT, α/β of linear quadratic model was assumed as 3 Gy for the tracheal bronchus. The tracheobronchial surface irradiated by more than 100 Gy3 tended to develop severe stenosis, which attributed to a more than 50% decrease in the luminal area. The proposed dose reconstruction technique can be a powerful tool to predict late radiation toxicity with spatial consideration.

  16. SU-E-T-519: Experimental Evaluation of Deterministic Acuros XB Radiation Transport Algorithm for Heterogeneity Dose Calculation Using the Radiological Physics Center's Lung Phantom.

    Science.gov (United States)

    Han, T; Mourtada, F; Repchak, R; Tonigan, J; Mikell, J; Howell, R; Salehpour, M; Molineu, A; Followill, D

    2012-06-01

    To evaluate the heterogeneity corrected dose calculations from the Acuros XB (AXB), a novel deterministic dose calculation algorithm based on grid-based Boltzmann transport equation solver (GBBS), for IMRT and VMAT plans. The Radiological Physics Center's lung phantom was used to create clinically equivalent IMRT and VMAT plans (RapidArc) with the Eclipse planning system 10.0 that were delivered using a Varian 23 iX. Absolute doses and relative dose distributions were measured with thermoluminescent dosimeters (TLDs) and radiochromic film. The measured dose distributions were compared with calculated doses from both AXB (11.0.3) and AAA (10.0.24) dose calculation algorithms. The AXB calculated dose-to-water and dose-to-medium were both compared to measurements. Gamma analysis (±7%/4mm, ±5%/3mm, and ±3%/3mm) was used to quantify correspondence between AXB dose distributions and the film measurements. The computation time between AAA and AXB were also evaluated. For TLD point doses, both AAA and AXB heterogeneity corrected dose calculations are within 5% inside the PTV for both IMRT and VMAT plans. The agreements observed between the measured and calculated doses for both AXB dose reporting methods are better than those observed with the AAA algorithm. The gamma analysis showed that the differences between AAA, AXB and film measurement met the RPC ±7%/4 mm criteria. The percent of pixels passing rate for both the AXB dose to medium and AXB dose to water are higher than AAA. The computation time between AAA and AXB are comparable for IMRT plans but AXB is significantly faster (4 times) than AAA for VMAT plans. The AXB implemented in the Eclipse planning system calculates a more accurate heterogeneity corrected dose than the AAA algorithm as compared to measurement in lung and improve the calculation speed for VMAT radiotherapy. Work supported by grants CA10953, CA81647, 2R44CA105806-02, CA016672 (NCI, DHHS). © 2012 American Association of Physicists in Medicine.

  17. A Challenge to Scientific Risk Estimation on Health Effects of Low Dose Radiation - An Overview

    Directory of Open Access Journals (Sweden)

    Tetsuya Ono

    2007-03-01

    Full Text Available Although experimental as well as epidemiological studies have revealed the health effects of ionizing radiation, most of our knowledge is for high doses of radiation, while little is known for low doses. For practical purposes, we estimate the risk of low dose radiation by extrapolating the effects at high doses to low doses in a linear relationship. However, several lines of evidence have accumulated in recent years that suggest this linear extrapolation is not necessarily correct and needs further scientific evaluation. Today, many scientists in the field are striving to understand the biological responses to low dose radiation. This work will provide new and perhaps convincing data which are necessary for risk estimation of low dose radiation. Here, I overview the background of the issue.

  18. Contribution of maternal radionuclide burdens to prenatal radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Sikov, M.R.; Hui, T.E.

    1996-05-01

    This report describes approaches to calculating and expressing radiation doses to the embryo/fetus from internal radionuclides. Information was obtained for selected, occupationally significant radioelements that provide a spectrum of metabolic and dosimetric characteristics. Evaluations are also presented for inhaled inert gases and for selected radiopharmaceuticals. Fractional placental transfer and/or ratios of concentration in the embryo/fetus to that in the woman were calculated for these materials. The ratios were integrated with data from biokinetic transfer models to estimate radioactivity levels in the embryo/fetus as a function of stage of pregnancy and time after entry into the transfer compartment or blood of the pregnant woman. These results are given as tables of deposition and retention in the embryo/fetus as a function of gestational age at exposure and elapsed time following exposure. Methodologies described by MIRD were extended to formalize and describe details for calculating radiation absorbed doses to the embryo/fetus. Calculations were performed using a model situation that assumed a single injection of 1 {mu}Ci into a woman`s blood; independent calculations were performed for administration at successive months of pregnancy. Gestational -stage-dependent dosimetric tabulations are given together with tables of correlations and relationships. Generalized surrogate dose factors and categorizations are provided in the report to provide for use in operational radiological protection situations. These approaches to calculation yield radiation absorbed doses that can be converted to dose equivalent by multiplication by quality factor. Dose equivalent is the most common quantity for stating prenatal dose limits in the United States and is appropriate for the types of effect that are usually associated with prenatal exposure. If it is desired to obtain alternatives for other purposes, this value can be multiplied by appropriate weighting factors.

  19. Organ doses from radiation therapy in atomic bomb survivors.

    Science.gov (United States)

    Kato, K; Antoku, S; Kodama, K; Kawamura, S; Fujita, Y; Komatsu, K; Awa, A A

    2001-06-01

    Previous surveys of radiation therapy among the Life Span Study (LSS) population at the Radiation Effects Research Foundation (RERF) revealed that 1,670 (1.4%) of the LSS participants received radiation treatments before 1984. The data on therapeutic radiation doses are indispensable for studying the relationship between radiation treatments and subsequent cancer occurrences. In this study, the radiation treatments were reproduced experimentally to determine the scattered radiation doses. The experiments were conducted using a female human phantom and various radiation sources, including a medium-voltage X-ray machine and a (60)Co gamma-ray source. Doses were measured using thermoluminescence dosimetry and ionization chambers. Radiation doses were determined for the salivary glands, thyroid gland, breast, lung, stomach, colon, ovary and active bone marrow. The results have been used for documenting the organ doses received by patients in previous surveys. The contribution of therapeutic irradiation to the occurrence of chromosome aberrations was studied using data on doses to active bone marrow from both radiation treatments and atomic bomb exposures in 26 RERF Adult Health Study participants. The results suggest that radiation treatments contributed to a large part of their frequencies of stable-type chromosome aberrations. The therapeutic radiation doses determined in the present study are available for investigating the effects of therapeutic irradiation on the subsequent primary cancers among atomic bomb survivors who received radiation treatments.

  20. Superficial dose evaluation of four dose calculation algorithms

    Science.gov (United States)

    Cao, Ying; Yang, Xiaoyu; Yang, Zhen; Qiu, Xiaoping; Lv, Zhiping; Lei, Mingjun; Liu, Gui; Zhang, Zijian; Hu, Yongmei

    2017-08-01

    Accurate superficial dose calculation is of major importance because of the skin toxicity in radiotherapy, especially within the initial 2 mm depth being considered more clinically relevant. The aim of this study is to evaluate superficial dose calculation accuracy of four commonly used algorithms in commercially available treatment planning systems (TPS) by Monte Carlo (MC) simulation and film measurements. The superficial dose in a simple geometrical phantom with size of 30 cm×30 cm×30 cm was calculated by PBC (Pencil Beam Convolution), AAA (Analytical Anisotropic Algorithm), AXB (Acuros XB) in Eclipse system and CCC (Collapsed Cone Convolution) in Raystation system under the conditions of source to surface distance (SSD) of 100 cm and field size (FS) of 10×10 cm2. EGSnrc (BEAMnrc/DOSXYZnrc) program was performed to simulate the central axis dose distribution of Varian Trilogy accelerator, combined with measurements of superficial dose distribution by an extrapolation method of multilayer radiochromic films, to estimate the dose calculation accuracy of four algorithms in the superficial region which was recommended in detail by the ICRU (International Commission on Radiation Units and Measurement) and the ICRP (International Commission on Radiological Protection). In superficial region, good agreement was achieved between MC simulation and film extrapolation method, with the mean differences less than 1%, 2% and 5% for 0°, 30° and 60°, respectively. The relative skin dose errors were 0.84%, 1.88% and 3.90%; the mean dose discrepancies (0°, 30° and 60°) between each of four algorithms and MC simulation were (2.41±1.55%, 3.11±2.40%, and 1.53±1.05%), (3.09±3.00%, 3.10±3.01%, and 3.77±3.59%), (3.16±1.50%, 8.70±2.84%, and 18.20±4.10%) and (14.45±4.66%, 10.74±4.54%, and 3.34±3.26%) for AXB, CCC, AAA and PBC respectively. Monte Carlo simulation verified the feasibility of the superficial dose measurements by multilayer Gafchromic films. And the rank

  1. Assessment of Organ Radiation Dose Associated with Uterine Artery Embolization

    Energy Technology Data Exchange (ETDEWEB)

    Glomset, O.; Hellesnes, J.; Heimland, N.; Hafsahl, G.; Smith, H.J. [Rikshospitalet Univ. Hospital, Oslo (Norway). Dept. of Radiology and the Interventional Centre

    2006-03-15

    Purpose: To evaluate the radiation dose to the skin, uterus, and ovaries during uterine artery embolization. Material and Methods: Guided uterine artery embolization for leiomyomata and two types of X-ray equipment with different dose levels were utilized during fluoroscopy in 20 women (ages ranging from 32 to 52 years, body weights from 55 to 68 kg). The first 13 women were treated using a non-pulsed system A, with 3.3 mm Al filtering and, for simplicity, a fixed peak voltage 80 kV. During treatment of the other 7 women, a pulsed system B with 5.4 mm Al filtering and an identical fixed voltage was used. The dose area product (DAP) was recorded. The vaginal dose of the first 13 patients and the peak skin dose of all patients were measured with thermoluminescent dosimeters (TLDs). TLDs were placed in the posterior vaginal fornix and on the skin at the beam entrance site. The uterine and ovarian doses were estimated based on the measured skin doses, normalized depth dose, and organ depth values. The effective dose (D eff ) was estimated based on the observed DAP values. The measured vaginal doses and the corresponding estimated uterine doses were compared statistically, as were the DAP values from systems A and B. Results: For system A, the mean fluoroscopic time was 20.9 min (range 12.7-31.1), and for system B 35.9 min (range 16.4-55.4). The mean numbers of angiographic exposures for systems A and B were 82 (range 30-164) and 37 (range 20-72), respectively. The mean peak skin dose for system A was 601.5 mGy (range 279-1030) and for system B 453 mGy (range 257-875). The mean DAP for system A was 88.6 Gy cm{sup 2} (range 41.4-161.0) and for system B 52.5 Gy cm{sup 2} (range 20.1-107.9). Statistical analysis showed a significant difference between the DAP values, the DAP for system B being the lower one. The mean estimated effective doses from systems A and B were 32 mSv (range 15.1-58.4) and 22 mSv (range 9-46), respectively. The mean estimated maximum uterine and

  2. Evaluation of biological effect of {sup 90}Sr beta radiation in human blood cells and dose-response curve elaboration; Avaliacao do efeito biologico da radiacao beta do {sup 90}Sr em celulas sanguineas humanas e elaboracao de curva dose-resposta

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Elaine Mendes de

    2000-07-01

    Among several environmental genotoxins, ionizing radiation has been received special attention because of its mutagenic, carcinogenic and teratogenic potential. In this context, the aim of this study was evaluate the effects of {sup 90}Sr beta radiation in human cells, in view of the scarcity of literature data. For that, blood cells of five healthy donors were irradiated in vitro with doses between 0.2 and 5.0 Gy in a {sup 90}Sr source (0.2 Gy/min) and were processed for chromosome aberration analysis and for comet assay. Cytogenetic results showed that the type of structural chromosome aberrations found more frequently were acentric fragments, double minutes and dicentrics. The values of {alpha} and {beta} coefficient of linear-quadratic model used to fit dose response curves showed that {sup 90}Sr beta radiation was more efficient in induction of lesions from only one ionizing track than two independent tracks in chromosome aberration formation. Apparently, {sup 90}Sr beta radiation neither influenced the modal number of chromosome in irradiated cells nor in cell cycle kinetic of analyzed dose interval. Concerning the comet assay, there was an increase in DNA migration in a dose dependent manner, evaluated by either image analysis system (tail moment) or visual classification (DNA damage), which dose-response relation was adequately fitted to non-linear regression model. Both adopted techniques were complement in evaluating the biological effect of {sup 90}Sr beta radiation in human cells. (author)

  3. Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

    Science.gov (United States)

    Wang, Chu

    correction factors for the MOSFET organ dose measurements in the following studies. Minor angular dependence (pediatric patients in the two age groups was measured. Imaging technique settings with variations of individual key imaging parameters were tested to observe the quantitative effect of imaging optimization or lack thereof. Along with each measurement, the two standard system output indices, the Air Kerma (AK) and Dose-Area Product (DAP), were also recorded and compared to the measured cardiac and skin doses -- the lack of correlation between the indices and the organ doses shed light to the substantial limitation of the indices in representing patient radiation dose, at least within the scope of this dissertation. Third, the effective dose (ED) for Posterior-Anterior and Lateral fluoroscopic imaging techniques for pediatric patients in the two age groups was determined. In addition, the dosimetric effect of removing the anti-scatter grid was studied, for which a factor-of-two ED rate reduction was observed for the imaging techniques. The Clinical Component involved analytical research to develop a validated retrospective cardiac dose reconstruction formulation and to propose the new Optimization Index which evaluates the level of optimization of the clinician's imaging usage during a procedure; and small sample group of actual procedures were used to demonstrate applicability of these formulations. In its entirety, the research represents a first-of-its-kind comprehensive approach in radiation dosimetry for pediatric cardiac catheterization; and separately, it is also modular enough that each individual section can serve as study templates for small-scale dosimetric studies of similar purposes. The data collected and algorithmic formulations developed can be of use in areas of personalized patient dosimetry, clinician training, image quality studies and radiation-associated health effect research.

  4. Calibration of photographic dosemeters to evaluate the personal equivalent dose, Hp (10), irradiated by different radiation qualities and angles of incidence; Calibracao de dosimetros fotograficos para avaliar o equivalente de dose pessoal, Hp(10), irradiados por diferentes qualidades de radiacao e angulos de incidencia

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, Christiana; Antonio Filho, Joao, E-mail: chsantoro@gmail.com, E-mail: jaf@ufpe.br [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Santos, Marcus Aurelio P.; Goncalves Filho, Luiz Carlos, E-mail: masantos@cnen.gov.br, E-mail: l.filho@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, Pe (Brazil)

    2013-07-01

    To use radiation detectors, should periodically perform tests and calibrations on instruments in order to verify its good functionality. One way to ascertain the quality of the instrument is to conduct a study of the angular dependence of the response of the radiation detectors. The photographic dosimetry has been used widely to quantify the radiation doses and to estimate levels of doses received by workers involved with X-and gamma radiation. Photographic dosimeters are used because provide wide range of exposure and good accuracy. One of the sources of error have been introduced by different irradiation geometries between calibration and measurement in radiation fields used in x-ray and gamma ray sources, therefore, there is a need for an evaluation of the sensitivity of dosimeters with variation of the angle of the incident beam. In this study were tested 190 photographic dosemeters in the Metrology Laboratory of the Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE) using the phantom H{sub p} (10), where the dosimeters are evaluated on the basis of the new operational magnitude for individual monitoring, the equivalent personal dose, H{sub p} (10). Angular dependence of these radiation detectors was studied in X radiation fields (in the range of 45 keV energy to 164 keV) and gamma radiation ({sup 137}Cs-662 keV e {sup 60}Co - 1250 keV)

  5. Evaluation of radiation proctitis

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, T.; Kuramoto, M.; Ikawa, K.; Kawasaki, H.; Korematsu, H. (Tokushima Univ. (Japan). School of Medicine)

    1981-05-01

    20 cases of radiation proctitis were treated from Jan. 1970 to Oct. 1980. In all of the cases, primary disease was uterine cancer; cancer of the cervix, 19 cases and cancer of the endometrium, 1 case. The primary cancer was stage I in 5 cases, stage II in 5 cases, stage III in 2 cases, stage IV 4 cases, and not clear in 4 cases. Radiation dose was 5,000 - 6,000 rad in most cases and given for 1 - 2 months. The period from radiotherapy to the onset of the complication was 30 days to 13 years, averaged 42 months. Complications were graded according to Sherman's classification; grade I was 1 case, grade II 6 cases, grade III 2 cases, grade IV 9 cases, and ''unknown'' was 2 cases, showing highest frequency of grade IV with fistula formation. Rectal bleeding was found in 14 cases with highest incidence, and proctovaginal fistula which caused fecal leak was found in 9 cases. Treatment was operative therapy in 15 cases, palliative therapy in 3 cases, and follow-up observation in 2 cases. Of 15 patients of operative therapy, 14 were subjected to proctostomy, and one was fistulectomy. Of 14 patients underwent proctostomy, 11 survived, two died, and one was lost to follow-up, and unknown, 1.

  6. CT angiography of the head-and-neck vessels acquired with low tube voltage, low iodine, and iterative image reconstruction: clinical evaluation of radiation dose and image quality.

    Directory of Open Access Journals (Sweden)

    Wei-lan Zhang

    Full Text Available OBJECTIVES: We aimed to assess the effectiveness and feasibility of head-and-neck Computed Tomography Angiography (CTA with low tube voltage and low concentration contrast media combined with iterative reconstruction algorithm. METHODS: 92 patients were randomly divided into group A and B: patients in group A received a conventional scan with 120 kVp and contrast media of 320 mgI/ml. Patients in group B, 80 kVp and contrast media of 270 mgI/ml were used along with iterative reconstruction algorithm techniques. Image quality, radiation dose and the effectively consumed iodine amount between two groups were analyzed and compared. RESULTS: Image quality of CTA of head-and-neck vessels obtained from patients in group B was significantly improved quantitatively and qualitatively. In addition, CT attenuation values in group B were also significantly higher than that in group A (p<0.001. Furthermore, compared with the protocol whereby 120 kVp and 320 mgI/dl were administrated, the mean radiation dose and consumed iodine amount in protocol B were also reduced by 50% and 15.6%, respectively (p<0.001. CONCLUSIONS: With the help of iterative reconstruction algorithm techniques, the head-and-neck CTA with diagnostic quality can be adequately acquired with low tube voltage and low concentration contrast media. This method could be potentially extended to include any part of the body to reduce the risks related to ionizing radiation.

  7. Low dose radiation enhances the Locomotor activity of D. melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Ki Moon; Lee, Buyng Sub; Nam Seon Young; Kim, Ji Young; Yang, Kwang Hee; Choi, Tae In; Kim, Cha Soon [Radiation Effect Research Team, Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., Gyeongju (Korea, Republic of)

    2013-04-15

    Mild stresses at low level including radiation can induce the beneficial effects in many vertebrate and invertebrate species. However, a large amount of studies in radiation biology have focused on the detrimental effects of high dose radiation (HDR) such as the increased incidence of cancers and developmental diseases. Low dose radiation (LDR) induces biologically favorable effects in diverse fields, for example, cancer development, genomic instability, immune response, and longevity. Our previous data indicated that LDR promotes cells proliferation of which degree is not much but significant, and microarray data explained that LDR irradiated fruit flies showing the augmented immunity significantly changed the program for gene expression of many genes in Gene Ontology (GO) categories related to metabolic process. Metabolic process in development one of major contributors in organism growth, interbreeding, motility, and aging. Therefore, it is valuable to examine whether LDR change the physiological parameters related to metabolism, and how LDR regulates the metabolism in D. melanogaster. In this study, to investigate that LDR influences change of the metabolism, a representative parameter, locomotor activity. In addition, the activation of several cellular signal molecules was determined to investigate the specific molecular mechanism of LDR effects on the metabolism. We explored whether ionizing radiation affects the motility activity. We performed the RING assays to evaluate the locomotor activity, a representative parameter presenting motility of fruit flies. HDR dramatically decreased the motor activity of irradiated flies. Surprisingly, the irradiated flies at low dose radiation in both acute and chronic showed the significantly increased locomotor activity, compared to non-irradiated flies. Irradiation would induce change of the several signal pathways for flies to respond to it. The activation of some proteins involved in the cells proliferation and stress

  8. Evaluation of X ray radiation doses in pediatric examinations of cranial computerized tomography based on optimization studies; Avaliacao das doses de radiacao X em exames pediatricos de tomografia computadorizada de cranio com base em estudos de otimizacao

    Energy Technology Data Exchange (ETDEWEB)

    Daros, Kellen Adriana Curci

    2005-07-01

    This paper identifies the technical conditions for CT examination which offers lowest absorbed dose and to attend the manufacturer recommendations as far the spatial resolution is concerned. The paper evaluates the absorbed dose during cranial CT in up to 6 years children satisfying the technical condition recommended by the manufacturer and routine clinical conditions. The paper also established a quantitative relationship among the absorbed dose and its distribution in the cranial regions of pediatric patients up to 6 years old in a way to estimate the doses subject to optimized conditions

  9. Measuring radiation dose in computed tomography using elliptic phantom and free-in-air, and evaluating iterative metal artifact reduction algorithm

    Science.gov (United States)

    Morgan, Ashraf

    The need for an accurate and reliable way for measuring patient dose in multi-row detector computed tomography (MDCT) has increased significantly. This research was focusing on the possibility of measuring CT dose in air to estimate Computed Tomography Dose Index (CTDI) for routine quality control purposes. New elliptic CTDI phantom that better represent human geometry was manufactured for investigating the effect of the subject shape on measured CTDI. Monte Carlo simulation was utilized in order to determine the dose distribution in comparison to the traditional cylindrical CTDI phantom. This research also investigated the effect of Siemens health care newly developed iMAR (iterative metal artifact reduction) algorithm, arthroplasty phantom was designed and manufactured that purpose. The design of new phantoms was part of the research as they mimic the human geometry more than the existing CTDI phantom. The standard CTDI phantom is a right cylinder that does not adequately represent the geometry of the majority of the patient population. Any dose reduction algorithm that is used during patient scan will not be utilized when scanning the CTDI phantom, so a better-designed phantom will allow the use of dose reduction algorithms when measuring dose, which leads to better dose estimation and/or better understanding of dose delivery. Doses from a standard CTDI phantom and the newly-designed phantoms were compared to doses measured in air. Iterative reconstruction is a promising technique in MDCT dose reduction and artifacts correction. Iterative reconstruction algorithms have been developed to address specific imaging tasks as is the case with Iterative Metal Artifact Reduction or iMAR which was developed by Siemens and is to be in use with the companys future computed tomography platform. The goal of iMAR is to reduce metal artifact when imaging patients with metal implants and recover CT number of tissues adjacent to the implant. This research evaluated i

  10. A comparative analysis of exposure doses between the radiation workers in dental and general hospital

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Nam Hee; Chung, Woon Kwan; Dong, Kyung Rae; Ju, Yong Jin; Song, Ha Jin [Dept. of Nuclear Engineering, Chosun University, Gwangju (Korea, Republic of); Choi, Eun Jin [Dept. of Public Health and Medicine, Dongshin University, Naju (Korea, Republic of)

    2015-02-15

    Research and investigation is required for the exposure dose of radiation workers to work in the dental hospital as increasing interest in exposure dose of the dental hospital recently accordingly, study aim to minimize radiation exposure by making a follow-up study of individual exposure doses of radiation workers, analyzing the status on individual radiation exposure management, prediction the radiation disability risk levels by radiation, and alerting the workers to the danger of radiation exposure. Especially given the changes in the dental hospital radiation safety awareness conducted the study in order to minimize radiation exposure. This study performed analyses by a comparison between general and dental hospital, comparing each occupation, with the 116,220 exposure dose data by quarter and year of 5,811 subjects at general and dental hospital across South Korea from January 1, 2008 through December 31, 2012. The following are the results obtained by analyzing average values year and quarter. In term of hospital, average doses were significantly higher in general hospitals than detal ones. In terms of job, average doses were higher in radiological technologists the other workers. Especially, they showed statistically significant differences between radiological technologists than dentists. The above-mentioned results indicate that radiation workers were exposed to radiation for the past 5 years to the extent not exceeding the dose limit (maximum 50 mSv y{sup -1}). The limitation of this study is that radiation workers before 2008 were excluded from the study. Objective evaluation standards did not apply to the work circumstance or condition of each hospital. Therefore, it is deemed necessary to work out analysis criteria that will be used as objective evaluation standard. It will be necessary to study radiation exposure in more precise ways on the basis of objective analysis standard in the future. Should try to minimize the radiation individual dose of

  11. Clinical evaluation of image quality and radiation dose reduction in upper abdominal computed tomography using model-based iterative reconstruction; comparison with filtered back projection and adaptive statistical iterative reconstruction.

    Science.gov (United States)

    Nakamoto, Atsushi; Kim, Tonsok; Hori, Masatoshi; Onishi, Hiromitsu; Tsuboyama, Takahiro; Sakane, Makoto; Tatsumi, Mitsuaki; Tomiyama, Noriyuki

    2015-09-01

    To evaluate the image quality of upper abdominal CT images reconstructed with model-based iterative reconstruction (MBIR) in comparison with filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) on scans acquired with various radiation exposure dose protocols. This prospective study was approved by our institutional review board, and informed consent was obtained from all 90 patients who underwent both control-dose (CD) and reduced-dose (RD) CT of the upper abdomen (unenhanced: n=45, contrast-enhanced: n=45). The RD scan protocol was randomly selected from three protocols; Protocol A: 12.5% dose, Protocol B: 25% dose, Protocol C: 50% dose. Objective image noise, signal-to-noise (SNR) ratio for the liver parenchyma, visual image score and lesion conspicuity were compared among CD images of FBP and RD images of FBP, ASIR and MBIR. RD images of MBIR yielded significantly lower objective image noise and higher SNR compared with RD images of FBP and ASIR for all protocols (PASIR and inferior to that in CD images for Protocols A and B, although the differences were not significant (P>.0083). Although 12.5%-dose MBIR images (mean size-specific dose estimates [SSDE] of 1.13mGy) yielded objective image noise and SNR comparable to CD-FBP images, at least a 50% dose (mean SSDE of 4.63mGy) would be needed to maintain the subjective image quality and the lesion conspicuity. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Cone beam computed tomography radiation dose and image quality assessments.

    Science.gov (United States)

    Lofthag-Hansen, Sara

    2010-01-01

    Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and

  13. Radiation Dose Risk and Diagnostic Benefit in Imaging Investigations

    CERN Document Server

    Dobrescu, Lidia

    2015-01-01

    The paper presents many facets of medical imaging investigations radiological risks. The total volume of prescribed medical investigations proves a serious lack in monitoring and tracking of the cumulative radiation doses in many health services. Modern radiological investigations equipment is continuously reducing the total dose of radiation due to improved technologies, so a decrease in per caput dose can be noticed, but the increasing number of investigations has determined a net increase of the annual collective dose. High doses of radiation are cumulated from Computed Tomography investigations. An integrated system for radiation safety of the patients investigated by radiological imaging methods, based on smart cards and Public Key Infrastructure allow radiation absorbed dose data storage.

  14. In Vivo Mutagenic Effect of Very Low Dose Radiation

    Science.gov (United States)

    Sykes, Pamela J.; Day, Tanya K.; Swinburne, Sarah J.; Lane, Joanne M.; Morley, Alexander A.; Hooker, Antony M.; Bhat, Madhava

    2006-01-01

    Almost all of our knowledge about the mutational effect of radiation has come from high dose studies which are generally not relevant to public exposure. The pKZ1 mouse recombination mutagenesis assay enables study of the mutational effect of very low doses of low LET radiation (μGy to cGy range) in a whole animal model. The mutational end-point studied is chromosomal inversion which is a common mutation in cancer. We have observed 1) a non-linear dose response of induced inversions in pKZ1 mice exposed to a wide dose range of low LET radiation, 2) the ability of low priming doses to cause an adaptive response to subsequent higher test doses and 3) the effect of genetic susceptibility where animals that are heterozygous for the Ataxia Telangiectasia gene (Atm) exhibit different responses to low dose radiation compared to their normal litter-mates. PMID:18648587

  15. Asian consortium on radiation dose of pediatric cardiac CT (ASCI-REDCARD)

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Peter K.T. [Hong Kong Baptist Hospital, Department of Radiology, Hong Kong, SAR (China); Goo, Hyun Woo [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Du, Jing [Beijing Anzhen Hospital, Capital Medical University, Department of Radiology, Beijing (China); Ip, Janice J.K. [Queen Mary Hospital, Department of Radiology, Hong Kong, SAR (China); Kanzaki, Suzu [National Cerebral and Cardiovascular Center, Department of Radiology, Osaka (Japan); Kim, Young Jin [Yonsei University, Shinchon Severance Hospital, Department of Radiology, Seoul (Korea, Republic of); Kritsaneepaiboon, Supika [Songklanagarind Hospital, Prince of Songkla University, Department of Radiology, Hat Yai (Thailand); Lilyasari, Oktavia [University of Indonesia, National Cardiovascular Center Harapan Kita, Department of Cardiology, Jakarta (Indonesia); Siripornpitak, Suvipaporn [Ramathibodi Hospital, Mahidol University, Department of Radiology, Salaya (Thailand)

    2017-07-15

    With incremental utilization of pediatric cardiac CT in congenital heart disease, it is imperative to define its current radiation dose levels in clinical practice in order to help imagers optimize CT protocols, particularly in Asia and other developing countries where CT physicists are not readily available. To evaluate current radiation dose levels and influencing factors in cardiac CT in children with congenital heart disease in Asia by conducting a retrospective multi-center, multi-vendor study. We included 1,043 pediatric cardiac CT examinations performed in 8 centers between January 2014 and December 2014 to evaluate congenital heart disease. In five weight groups, we calculated radiation dose metrics including volume CT dose index, size-specific dose estimate, dose-length product and effective dose. Age at CT exam, gender, tube voltage, scan mode, CT indication and image reconstruction algorithm were analyzed to learn whether they influenced CT radiation dose. Volume CT dose index, size-specific dose estimate, dose-length product and effective dose of pediatric cardiac CT showed variations in the range of 4.3-23.8 mGy, 4.9-17.6 mGy, 55.8-501.3 mGy circle cm and 1.5-3.2 mSv, respectively, within five weight groups. Gender, tube voltage, scan mode and cardiac function assessment significantly influenced CT radiation dose. This multi-center, multi-vendor study demonstrated variations in radiation dose metrics of pediatric cardiac CT reflecting current practice in Asia. Gender, tube voltage, scan mode and cardiac function assessment should be considered as essential radiation dose-influencing factors in developing optimal pediatric cardiac CT protocols. (orig.)

  16. Methodology for estimating radiation dose rates to freshwater biota exposed to radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Blaylock, B.G.; Frank, M.L.; O`Neal, B.R.

    1993-08-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy`s (DOE`s) recommended dose rate limit of 0.4 mGy h{sup {minus}1} (1 rad d{sup {minus}1}). A dose rate no greater than 0.4 mGy h{sup {minus}1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE`s recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0. 1 mGy h{sup {minus}1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be conducted.

  17. Direct determination of external radiation dose in human blood

    CERN Document Server

    Tanir, AG; Sahiner, E; Bolukdemir, MH; Koc, K; Meric, N; Keles, SK; Kucuk, O

    2014-01-01

    In this study it was shown that it is possible to determine radiation doses from external beam therapy both directly and retrospectively from a human blood sample. To the best of our knowledge no other studies exist on the direct measurement of doses received by a person from external beam therapy. Optically stimulated luminescence counts from a healthy blood sample exposed to an external radiation source were measured. Blood aliquots were given 0, 1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 100 and 200Gy beta doses and their decay and dose-response curves were plotted. While the luminescence intensities were found to be relatively low for the doses smaller than 10Gy, they were measured considerably higher for doses greater than 10Gy. The dose received by the blood aliquots was determined by interpolating the luminescence counts of 10Gy to the dose-response curve. This study has important ramifications for healthcare, medicine and radiation protection

  18. CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

    Science.gov (United States)

    Carcinogenic Effects of Low Doses of Ionizing RadiationR Julian Preston, Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711The form of the dose-response curve for radiation-induced cancers, particu...

  19. Low dose radiation and plant growth

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Jae; Lee, Hae Youn; Park, Hong Sook

    2001-03-01

    Ionizing radiation includes cosmic radiation, earth radiation, radionuclides for the medical purpose and nuclear industry, fallout radiation. From the experimental results of various radiation effects on seeds or seedlings, it was found that germination rate, development, respiration rate, reproduction and blooming were accelerated compared with the control. In mammal, hormesis phenomenon manifested itself in increased disease resistance, lifespan, and decreased rate of tumor incidence. In plants, it was shown that germination, sprouting, growth, development, blooming and resistance to disease were accelerated.

  20. A Paradigm Shift in Low Dose Radiation Biology

    Directory of Open Access Journals (Sweden)

    Z. Alatas

    2015-08-01

    Full Text Available When ionizing radiation traverses biological material, some energy depositions occur and ionize directly deoxyribonucleic acid (DNA molecules, the critical target. A classical paradigm in radiobiology is that the deposition of energy in the cell nucleus and the resulting damage to DNA are responsible for the detrimental biological effects of radiation. It is presumed that no radiation effect would be expected in cells that receive no direct radiation exposure through nucleus. The risks of exposure to low dose ionizing radiation are estimated by extrapolating from data obtained after exposure to high dose radiation. However, the validity of using this dose-response model is controversial because evidence accumulated over the past decade has indicated that living organisms, including humans, respond differently to low dose radiation than they do to high dose radiation. Moreover, recent experimental evidences from many laboratories reveal the fact that radiation effects also occur in cells that were not exposed to radiation and in the progeny of irradiated cells at delayed times after radiation exposure where cells do not encounter direct DNA damage. Recently, the classical paradigm in radiobiology has been shifted from the nucleus, specifically the DNA, as the principal target for the biological effects of radiation to cells. The universality of target theory has been challenged by phenomena of radiation-induced genomic instability, bystander effect and adaptive response. The new radiation biology paradigm would cover both targeted and non-targeted effects of ionizing radiation. The mechanisms underlying these responses involve biochemical/molecular signals that respond to targeted and non-targeted events. These results brought in understanding that the biological response to low dose radiation at tissue or organism level is a complex process of integrated response of cellular targets as well as extra-cellular factors. Biological understanding of

  1. Energies, health, medicine. Low radiation doses; Energies, sante, medecine. Les faibles doses de rayonnement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This file concerns the biological radiation effects with a special mention for low radiation doses. The situation of knowledge in this area and the mechanisms of carcinogenesis are detailed, the different directions of researches are given. The radiation doses coming from medical examinations are given and compared with natural radioactivity. It constitutes a state of the situation on ionizing radiations, known effects, levels, natural radioactivity and the case of radon, medicine with diagnosis and radiotherapy. (N.C.)

  2. Radiation dose during CT examination of the maxillofacial region

    Energy Technology Data Exchange (ETDEWEB)

    Iwai, Kazuo; Hashimoto, Koji; Honjoya, Takashi; Mase, Naomichi; Ohki, Tohru; Shinoda, Koji [Nihon Univ., Tokyo (Japan). School of Dentistry; Maruyama, Takashi; Nishizawa, Kanae

    2000-11-01

    A study was conducted to measure the radiation dose absorbed by organs and tissues during computed tomographic (CT) examinations of the mandibular, maxillary and temporomandibular joint (TMJ) regions, and to evaluate the effective dose for these examinations on the basis of the ICRP 60 recommendations. Measurements of organ or tissue dose were carried out on the gonads, breasts, red bone marrow, lungs, thyroid gland, oesophagus, stomach, liver, colon, bladder, brain, rectum, salivary glands, tongue, eyes and skin using a Toshiba TCT-700S. Irradiation was done at 120 kV and 140 mA. The doses were measured with a thermoluminescent dosimeter (Panasonic UD-170A and UD-110S) and a Rando woman phantom. Two types of TLD were used to determine experimentally the organ or tissue doses in the phantom: Panasonic UD-170A TLDs were used for measurement inside useful X-ray beams, while UD-110S TLDs were used for measurement of the lower level outside. The TLDs were calibrated under the conditions for X-rays from a KXO-12 unit (Toshiba Co.) with the same technical parameters as those for the CT scanner using an ionization chamber which was traceable to the national standard at the Electrotechnical Laboratory in Tsukuba (Japan). The resultant effective dose for examination of the mandibular, maxillary and TMJ regions were 1.7 mSv, 0.65 mSv, 1.8 mSv, respectively. These data can be used to estimate radiation risks from CT examinations of the maxillofacial region. (author)

  3. [About Dose-Effect Relationship in the Environment Radiation Protection].

    Science.gov (United States)

    Udalova, A A

    2015-01-01

    One of the most important stages in the development of a methodology for the environment radiation protection is the assessment and justification of critical radiation exposure levels for ecosystem components. In this study application of the approach for critical dose level estimation is demonstrated on the example of the data about ionizing radiation effect on reproduction and survival of agricultural plants after acute and chronic exposures. Influence of the type of dose-effect relationship on the estimated values of the critical doses and dose rates is studied using three models (linear, logarithmic and logistic). The findings obtained do not provide any robust recommendations in favor of one of the three tested functions. The models of dose-effect relationship (threshold or non-threshold) and types of radiation-induced effects (stochastic and deterministic) are discussed from the viewpoint of developing a system for radiation protection of human and non-human biota.

  4. Dose evaluation of organs at risk (OAR) cervical cancer using dose volume histogram (DVH) on brachytherapy

    Science.gov (United States)

    Arif Wibowo, R.; Haris, Bambang; Inganatul Islamiyah, dan

    2017-05-01

    Brachytherapy is one way to cure cervical cancer. It works by placing a radioactive source near the tumor. However, there are some healthy tissues or organs at risk (OAR) such as bladder and rectum which received radiation also. This study aims to evaluate the radiation dose of the bladder and rectum. There were 12 total radiation dose data of the bladder and rectum obtained from patients’ brachytherapy. The dose of cervix for all patients was 6 Gy. Two-dimensional calculation of the radiation dose was based on the International Commission on Radiation Units and Measurements (ICRU) points or called DICRU while the 3-dimensional calculation derived from Dose Volume Histogram (DVH) on a volume of 2 cc (D2cc). The radiation dose of bladder and rectum from both methods were analysed using independent t test. The mean DICRU of bladder was 4.33730 Gy and its D2cc was4.78090 Gy. DICRU and D2cc bladder did not differ significantly (p = 0.144). The mean DICRU of rectum was 3.57980 Gy and 4.58670 Gy for D2cc. The mean DICRU of rectum differed significantly from D2cc of rectum (p = 0.000). The three-dimensional method radiation dose of the bladder and rectum was higher than the two-dimensional method with ratios 1.10227 for bladder and 1.28127 for rectum. The radiation dose of the bladder and rectum was still below the tolerance dose. Two-dimensional calculation of the bladder and rectum dose was lower than three-dimension which was more accurate due to its calculation at the whole volume of the organs.

  5. Radiation dose rates from UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Friend, P.J. [Urenco, Capenhurst (United Kingdom)

    1991-12-31

    This paper describes the results of many studies, both theoretical and experimental, which have been carried out by Urenco over the last 15 years into radiation dose rates from uranium hexafluoride (UF{sub 6}) cylinders. The contents of the cylinder, its history, and the geometry all affect the radiation dose rate. These factors are all examined in detail. Actual and predicted dose rates are compared with levels permitted by IAEA transport regulations.

  6. Avaliação das doses de radiação em uretrocistografia miccional de crianças Evaluation of radiation dose in voiding cystourethrography in children

    Directory of Open Access Journals (Sweden)

    Leonardo Vieira Travassos

    2009-02-01

    Full Text Available OBJETIVO: Analisar o produto dose-área, a dose de entrada na pele do paciente e as doses relativas à fluoroscopia e às radiografias em exames de cistouretrografia miccional em crianças. MATERIAIS E MÉTODOS: Foram avaliados os procedimentos em 37 pacientes, realizados por quatro médicos do serviço. As medições foram realizadas com um equipamento composto de uma câmara de ionização acoplada diretamente à saída do tubo de raios X e um eletrômetro (Diamentor ligado diretamente ao computador, para a coleta dos dados. RESULTADOS: Foi observada alguma heterogeneidade na realização do procedimento, que não segue padrão de técnica radiográfica. São realizadas em média 11 radiografias por exame, usando tempo longo de fluoroscopia, com dose média final mais alta que a encontrada em referências da literatura. CONCLUSÃO: A adoção da técnica de alta quilovoltagem nas radiografias e o uso restrito da fluoroscopia podem proporcionar importante redução das doses durante a realização deste procedimento, porque o maior contribuinte para as altas doses verificadas foi a utilização da fluoroscopia.OBJECTIVE: To evaluate dose-area product, skin entrance dose and doses from fluoroscopy and radiography in voiding cystourethrography studies of pediatric patients. MATERIALS AND METHODS: Procedures performed in 37 patients by four physicians of the institution were evaluated. Measurements were performed with an equipment including an ionization chamber directly coupled to the x-ray tube window and an electrometer (Diamentor connected to a computer for data collection. RESULTS: Some procedures heterogeneity was observed and guidelines for good radiographic techniques were not followed. On average, 11 radiographies are performed for each study, with extended fluoroscopy time delivering a higher average final dose than those reported in the literature. CONCLUSION: The adoption of radiography with high kilovoltage technique and restricted

  7. Radiochromic Plastic Films for Accurate Measurement of Radiation Absorbed Dose and Dose Distributions

    DEFF Research Database (Denmark)

    McLaughlin, W. L.; Miller, Arne; Fidan, S.

    1977-01-01

    Thin radiochromic dye films are useful for measuring large radiation absorbed doses (105–108 rads) and for high-resolution imaging of dose patterns produced by penetrating radiation beams passing through non-homogeneous media. Certain types of amino-substituted triarylmethane cyanides dissolved...... in polymeric solutions can be cast into flexible free-standing thin films of uniform thickness and reproducible response to ultraviolet and ionizing radiation. The increase in optical density versus energy deposited by radiation is linear over a wide range of doses and is for practical purposes independent...... of dose rate (1–1014 rad s−1). Upon irradiation of the film, the profile of the radiation field is registered as a permanent colored image of the dose distribution. Unlike most other types of dyed plastic dose meters, the optical density produced by irradiation is in most cases stable for periods...

  8. Measurement and evaluation of internal dose

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tae Young; Chang, S. Y.; Lee, J. I.; Song, M. Y. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-01-01

    This report describes the contents and results for implementation of internal radiating monitoring programme, measurement of uranium present in lung by lung counter and assessment of committed effective dose for radiation workers of KNFC. The aim of radiation protection was achieved by implementing this activity. 8 refs., 14 tabs. (Author)

  9. Clinical practitioners' knowledge of ionizing radiation doses in ...

    African Journals Online (AJOL)

    Background: Observation has shown a preponderance of irrelevant, unjustified and perhaps unnecessary radiological requests in the study area. The consequences of this on the patients' doses and population collective dose may be dire. Objective: To assess Clinicians/Referrers' knowledge of radiation doses of patients ...

  10. Effects of high dose rate gamma radiation on survival and reproduction of Biomphalaria glabrata

    Energy Technology Data Exchange (ETDEWEB)

    Cantinha, Rebeca S.; Nakano, Eliana [Instituto Butantan, Sao Paulo, SP (Brazil). Lab. de Parasitologia], e-mail: rebecanuclear@gmail.com, e-mail: eliananakano@butantan.gov.br; Borrely, Sueli I. [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes], e-mail: sborrely@ipen.br; Amaral, Ademir; Melo, Ana M.M.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia (GERAR)], e-mail: amaral@ufpe.br; Silva, Luanna R.S. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia. Lab. de Radiobiologia], e-mail: amdemelo@hotmail.com, e-mail: luannaribeiro_lua@hotmail.com

    2009-07-01

    Ionizing radiations are known as mutagenic agents, causing lethality and infertility. This characteristic has motivated its application on animal biological control. In this context, the freshwater snail Biomphalaria glabrata can be considered an excellent experimental model to study effects of ionizing radiations on lethality and reproduction. This work was designed to evaluate effects of {sup 60}Co gamma radiation at high dose rate (10.04 kGy/h) on B. glabrata. For this purpose, adult snails were selected and exposed to doses ranging from 20 to 100 Gy, with 10 Gy intervals; one group was kept as control. There was not effect of dose rate in the lethality of gamma radiation; the value of 64,3 Gy of LD{sub 50} obtained in our study was similar to that obtained by other authors with low dose rates. Nevertheless, our data suggest that there was a dose rate effect in the reproduction. On all dose levels, radiation improved the production of embryos for all exposed individuals. However, viability indexes were below 6% and, even 65 days after irradiation, fertility was not recovered. These results are not in agreement with other studies using low dose rates. Lethality was obtained in all groups irradiated, and the highest doses presented percentiles of dead animals above 50%. The results demonstrated that doses of 20 and 30 Gy were ideal for population control of B. glabrata. Further studies are needed; nevertheless, this research evidenced great potential of high dose rate gamma radiation on B. glabrata reproductive control. (author)

  11. Development of Plant Application Technique of Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Byung Yeoup; Kim, Jae Sung; Lim, Yong Taek (and others)

    2007-07-15

    The project was carried out to achieve three aims. First, development of application techniques of cell-stimulating effects by low-dose radiation. Following irradiation with gamma-rays of low doses, beneficial effects in crop germination, early growth, and yield were investigated using various plant species and experimental approaches. For the actual field application, corroborative studies were also carried out with a few concerned experimental stations and farmers. Moreover, we attempted to establish a new technique of cell cultivation for industrial mass-production of shikonin, a medicinal compound from Lithospermum erythrorhizon and thereby suggested new application fields for application techniques of low-dose radiation. Second, elucidation of action mechanisms of ionizing radiation in plants. By investigating changes in plant photosynthesis and physiological metabolism, we attempted to elucidate physiological activity-stimulating effects of low-dose radiation and to search for radiation-adaptive cellular components. Besides, analyses of biochemical and molecular biological mechanisms for stimulus-stimulating effects of low-dose radiation were accomplished by examining genes and proteins inducible by low-dose radiation. Third, development of functional crop plants using radiation-resistant factors. Changes in stress-tolerance of plants against environmental stress factors such as light, temperature, salinity and UV-B stress after exposed to low-dose gamma-rays were investigated. Concerned reactive oxygen species, antioxidative enzymes, and antioxidants were also analyzed to develop high value-added and environment-friendly functional plants using radiation-resistant factors. These researches are important to elucidate biological activities increased by low-dose radiation and help to provide leading technologies for improvement of domestic productivity in agriculture and development of high value-added genetic resources.

  12. Clinical evaluation of image quality and radiation dose reduction in upper abdominal computed tomography using model-based iterative reconstruction; comparison with filtered back projection and adaptive statistical iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Nakamoto, Atsushi, E-mail: a-nakamoto@radiol.med.osaka-u.ac.jp; Kim, Tonsok, E-mail: kim@radiol.med.osaka-u.ac.jp; Hori, Masatoshi, E-mail: mhori@radiol.med.osaka-u.ac.jp; Onishi, Hiromitsu, E-mail: h-onishi@radiol.med.osaka-u.ac.jp; Tsuboyama, Takahiro, E-mail: t-tsuboyama@radiol.med.osaka-u.ac.jp; Sakane, Makoto, E-mail: m-sakane@radiol.med.osaka-u.ac.jp; Tatsumi, Mitsuaki, E-mail: m-tatsumi@radiol.med.osaka-u.ac.jp; Tomiyama, Noriyuki, E-mail: tomiyama@radiol.med.osaka-u.ac.jp

    2015-09-15

    Highlights: • MBIR significantly improves objective image quality. • MBIR reduces the radiation dose by 87.5% without increasing objective image noise. • A half dose will be needed to maintain the subjective image quality. - Abstract: Purpose: To evaluate the image quality of upper abdominal CT images reconstructed with model-based iterative reconstruction (MBIR) in comparison with filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) on scans acquired with various radiation exposure dose protocols. Materials and methods: This prospective study was approved by our institutional review board, and informed consent was obtained from all 90 patients who underwent both control-dose (CD) and reduced-dose (RD) CT of the upper abdomen (unenhanced: n = 45, contrast-enhanced: n = 45). The RD scan protocol was randomly selected from three protocols; Protocol A: 12.5% dose, Protocol B: 25% dose, Protocol C: 50% dose. Objective image noise, signal-to-noise (SNR) ratio for the liver parenchyma, visual image score and lesion conspicuity were compared among CD images of FBP and RD images of FBP, ASIR and MBIR. Results: RD images of MBIR yielded significantly lower objective image noise and higher SNR compared with RD images of FBP and ASIR for all protocols (P < .01) and CD images of FBP for Protocol C (P < .05). Although the subjective image quality of RD images of MBIR was almost acceptable for Protocol C, it was inferior to that of CD images of FBP for Protocols A and B (P < .0083). The conspicuity of the small lesions in RD images of MBIR tended to be superior to that in RD images of FBP and ASIR and inferior to that in CD images for Protocols A and B, although the differences were not significant (P > .0083). Conclusion: Although 12.5%-dose MBIR images (mean size-specific dose estimates [SSDE] of 1.13 mGy) yielded objective image noise and SNR comparable to CD-FBP images, at least a 50% dose (mean SSDE of 4.63 mGy) would be needed to

  13. Measurements of Ionizing Radiation Doses Induced by High Irradiance Laser on Targets in LCLS MEC Instrument

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Liu, J. C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Prinz, A. A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Rokni, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tran, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Woods, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Xia, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Galter, e. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lee, H. -J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Milathianaki, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Nagler, B. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2014-01-21

    Comprehensive measurements for photon and neutron radiation doses generated from laser-plasma interaction at SLAC’s MEC laser facility have been conducted. The goals of the measurements were to; determine the radiation dose per laser shot as a function of laser, optic and target parameters that are relevant to the MEC laser operations; validate the RPD-developed analytic model for photon dose calculations; and evaluate the performance of various types of passive and active detectors in the laser-induced radiation fields.

  14. The development of remote wireless radiation dose monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin-woo [KAERI - Korea Atomic Energy Research Institute, Jeongup-si (Korea, Republic of); Chonbuk National University, Jeonjoo-Si (Korea, Republic of); Jeong, Kyu-hwan [KINS - Korea Institute of Nuclear Safety, Daejeon-Si (Korea, Republic of); Kim, Jong-il [Chonbuk National University, Jeonjoo-Si (Korea, Republic of); Im, Chae-wan [REMTECH, Seoul-Si (Korea, Republic of)

    2015-07-01

    Internet of things (IoT) technology has recently shown a large flow of IT trends in human life. In particular, our lives are now becoming integrated with a lot of items around the 'smart-phone' with IoT, including Bluetooth, Near Field Communication (NFC), Beacons, WiFi, and Global Positioning System (GPS). Our project focuses on the interconnection of radiation dosimetry and IoT technology. The radiation workers at a nuclear facility should hold personal dosimeters such as a Thermo-Luminescence Dosimeter (TLD), an Optically Stimulated Luminescence Dosimeter (OSL), pocket ionization chamber dosimeters, an Electronic Personal Dosimeter (EPD), or an alarm dosimeter on their body. Some of them have functions that generate audible or visible alarms to radiation workers in a real working area. However, such devices used in radiation fields these days have no functions for communicating with other areas or the responsible personnel in real time. In particular, when conducting a particular task in a high dose area, or a number of repair works within a radiation field, radiation dose monitoring is important for the health of the workers and the work efficiency. Our project aims at the development of a remote wireless radiation dose monitoring system (RWRD) that can be used to monitor the radiation dose in a nuclear facility for radiation workers and a radiation protection program In this project, a radiation dosimeter is the detection device for personal radiation dose, a smart phone is the mobile wireless communication tool, and, Beacon is the wireless starter for the detection, communication, and position of the worker using BLE (Bluetooth Low Energy). In this report, we report the design of the RWRD and a demonstration case in a real radiation field. (authors)

  15. Optical tomography for measuring dose distribution in radiation therapy

    Directory of Open Access Journals (Sweden)

    Kauppinen Matti

    2014-01-01

    Full Text Available The dosimetry is used to verify the dose magnitude with artificial samples (phantoms before giving the planned radiation therapy to the patient. Typically, dose distribution is measured only in a single point or on a two-dimensional matrix plane. New techniques of radiation therapy ensure more detailed planning of radiation dose distribution which will lead to the need of measuring the radiation dose distribution three-dimensionally. The gel dosimetry is used to indicate and determine the ionizing radiation three-dimensionally. The radiation causes changes in chemical properties of the gel. The radiation dose distribution is defined by measuring the chemical changes. A conventional method is the magnetic resonance imaging and a new possibility is optical computed tomography (optical-CT. The optical-CT is much cheaper and more practical than magnetic resonance imaging. In this project, an optical-CT based method device was built by aiming at low material costs and a simple realization. The constructed device applies the charge coupled device camera and fluorescent lamp technologies. The test results show that the opacity level of the radiated gel can be measured accurately enough. The imaging accuracy is restricted by the optical distortion, e. g. vignetting, of the lenses, the distortion of a fluorescent lamp as the light source and a noisy measuring environment.

  16. Evaluation of dose to cardiac structures during breast irradiation

    DEFF Research Database (Denmark)

    Aznar, Marianne; Korreman, Stine; Pedersen, Anders N

    2011-01-01

    Objective: Adjuvant radiotherapy for breast cancer can lead to late cardiac complications. The highest radiation doses are likely to be to the anterior portion of the heart, including the left anterior descending coronary artery (LAD). The purpose of this work was to assess the radiation doses...... delivered to the heart and the LAD in respiration-adapted radiotherapy of patients with left-sided breast cancer. Methods: 24 patients referred for adjuvant radiotherapy after breast-conserving surgery for left-sided lymph node positive breast cancer were evaluated. The whole heart, the arch of the LAD...... and the whole LAD were contoured. The radiation doses to all three cardiac structures were evaluated. Results: For 13 patients, the plans were acceptable based on the criteria set for all 3 contours. For seven patients, the volume of heart irradiated was well below the set clinical threshold whereas a high dose...

  17. Radiation dose and image quality for paediatric interventional cardiology

    Energy Technology Data Exchange (ETDEWEB)

    Vano, E [Radiology Department, Medicine School, Complutense University and San Carlos University Hospital, 28040 Madrid (Spain); Ubeda, C [Clinical Sciences Department, Faculty of the Science of Health, Tarapaca University, 18 de Septiembre 2222, Arica (Chile); Leyton, F [Institute of Public Health of Chile, Marathon 1000, Nunoa, Santiago (Chile); Miranda, P [Hemodynamic Department, Cardiovascular Service, Luis Calvo Mackenna Hospital, Avenida Antonio Varas 360, Providencia, Santiago (Chile)], E-mail: eliseov@med.ucm.es

    2008-08-07

    Radiation dose and image quality for paediatric protocols in a biplane x-ray system used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 {mu}Gy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 {mu}Gy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25-45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the x-ray system. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures.

  18. CANCER RISKS ATTRIBUTABLE TO LOW DOSES OF IONIZING RADIATION - ASSESSING WHAT WE REALLY KNOW?

    Science.gov (United States)

    Cancer Risks Attributable to Low Doses of Ionizing Radiation - What Do We Really Know?AbstractHigh doses of ionizing radiation clearly produce deleterious consequences in humans including, but not exclusively, cancer induction. At very low radiation doses the situatio...

  19. Online Radiation Dose Measurement System for ATLAS experiment

    CERN Document Server

    Mandić, I; The ATLAS collaboration

    2012-01-01

    Particle detectors and readout electronics in the high energy physics experiment ATLAS at the Large Hadron Collider at CERN operate in radiation field containing photons, charged particles and neutrons. The particles in the radiation field originate from proton-proton interactions as well as from interactions of these particles with material in the experimental apparatus. In the innermost parts of ATLAS detector components will be exposed to ionizing doses exceeding 100 kGy. Energetic hadrons will also cause displacement damage in silicon equivalent to fluences of several times 10e14 1 MeV-neutrons per cm2. Such radiation doses can have severe influence on the performance of detectors. It is therefore very important to continuously monitor the accumulated doses to understand the detector performance and to correctly predict the lifetime of radiation sensitive components. Measurements of doses are important also to verify the simulations and represent a crucial input into the models used for predicting future ...

  20. Low dose ionizing radiation induced acoustic neuroma: A putative link?

    Directory of Open Access Journals (Sweden)

    Sachin A Borkar

    2012-01-01

    Full Text Available Although exposure to high dose ionizing radiation (following therapeutic radiotherapy has been incriminated in the pathogenesis of many brain tumors, exposure to chronic low dose ionizing radiation has not yet been shown to be associated with tumorigenesis. The authors report a case of a 50-year-old atomic reactor scientist who received a cumulative dose of 78.9 mSv over a 10-year period and was detected to have an acoustic neuroma another 15 years later. Although there is no proof that exposure to ionizing radiation was the cause for the development of the acoustic neuroma, this case highlights the need for extended follow-up periods following exposure to low dose ionizing radiation.

  1. Radiation dose measurement of paediatric patients in Estonia

    Energy Technology Data Exchange (ETDEWEB)

    Kepler, K. [Training Centre of Medical Physics and Biomedical Engineering, University of Tartu (Estonia); Lintrop, M. [Department of Radiology, Tartu University Hospital, Tartu (Estonia); Servomaa, A.; Parviainen, T. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland); Eek, V.; Filippova, I. [Estonian Radiation Protection Centre, Tallinn (Estonia)

    2003-06-01

    According to the Medical Exposure Directive (97/43/Euratom) the radiation doses to patients should be measured in every hospital and doses should be compared to the reference doses established by the competent authorities. Special attention should be paid to the paediatric x-ray examinations, because the paediatric patients are more radiosensitive than adult patients. The requirement of measurements of radiation dose to patients is not yet included in the Estonian radiation act, but the purpose to join the European Communities makes the quality control in radiology very actual in Estonia. The necessity exists to introduce suitable measurement methods in the Xray departments of Estonian hospitals for establishing feedback system for radiologists, radiographers and medical physicists in optimising the radiation burden of patients and image quality. (orig.)

  2. Painting Dose: The ART of Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Hannah J. [College of Physicians & Surgeons, Columbia University, New York, New York (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Zietman, Anthony L. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States); Efstathiou, Jason A., E-mail: jefstathiou@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States)

    2016-11-15

    The discovery of X rays in 1895 captivated society like no other scientific advance. Radiation instantly became the subject not only of numerous scientific papers but also of circus bazaars, poetry, fiction, costume design, comics, and marketing for household items. Its spread was “viral.” What is not well known, however, is its incorporation into visual art, despite the long tradition of medicine and surgery as a subject in art. Using several contemporary search methods, we identified 5 examples of paintings or sculpture that thematically feature radiation therapy. All were by artists with exhibited careers in art: Georges Chicotot, Marcel Duchamp, David Alfaro Siqueiros, Robert Pope, and Cookie Kerxton. Each artist portrays radiation differently, ranging from traditional healer, to mysterious danger, to futuristic propaganda, to the emotional challenges of undergoing cancer therapy. This range captures the complex role of radiation as both a therapy and a hazard. Whereas some of these artists are now world famous, none of these artworks are as well known as their surgical counterparts. The penetration of radiation into popular culture was rapid and pervasive; yet, its role as a thematic subject in art never fully caught on, perhaps because of a lack of understanding of the technology, radiation's intangibility, or even a suppressive effect of society's ambivalent relationship with it. These 5 artists have established a rich foundation upon which pop culture and art can further develop with time to reflect the extraordinary progress of modern radiation therapy.

  3. Painting Dose: The ART of Radiation.

    Science.gov (United States)

    Roberts, Hannah J; Zietman, Anthony L; Efstathiou, Jason A

    2016-11-15

    The discovery of X rays in 1895 captivated society like no other scientific advance. Radiation instantly became the subject not only of numerous scientific papers but also of circus bazaars, poetry, fiction, costume design, comics, and marketing for household items. Its spread was "viral." What is not well known, however, is its incorporation into visual art, despite the long tradition of medicine and surgery as a subject in art. Using several contemporary search methods, we identified 5 examples of paintings or sculpture that thematically feature radiation therapy. All were by artists with exhibited careers in art: Georges Chicotot, Marcel Duchamp, David Alfaro Siqueiros, Robert Pope, and Cookie Kerxton. Each artist portrays radiation differently, ranging from traditional healer, to mysterious danger, to futuristic propaganda, to the emotional challenges of undergoing cancer therapy. This range captures the complex role of radiation as both a therapy and a hazard. Whereas some of these artists are now world famous, none of these artworks are as well known as their surgical counterparts. The penetration of radiation into popular culture was rapid and pervasive; yet, its role as a thematic subject in art never fully caught on, perhaps because of a lack of understanding of the technology, radiation's intangibility, or even a suppressive effect of society's ambivalent relationship with it. These 5 artists have established a rich foundation upon which pop culture and art can further develop with time to reflect the extraordinary progress of modern radiation therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Mortality from diseases other than cancer following low doses of ionizing radiation

    DEFF Research Database (Denmark)

    Vrijheid, M; Cardis, E; Ashmore, P

    2007-01-01

    BACKGROUND: Ionizing radiation at very high (radio-therapeutic) dose levels can cause diseases other than cancer, particularly heart diseases. There is increasing evidence that doses of the order of a few sievert (Sv) may also increase the risk of non-cancer diseases. It is not known, however......, whether such effects also occur following the lower doses and dose rates of public health concern. METHODS: We used data from an international (15-country) nuclear workers cohort study to evaluate whether mortality from diseases other than cancer is related to low doses of external ionizing radiation....... Analyses included 275 312 workers with adequate information on socioeconomic status, over 4 million person-years of follow-up and an average cumulative radiation dose of 20.7 mSv; 11 255 workers had died of non-cancer diseases. RESULTS: The excess relative risk (ERR) per Sv was 0.24 [95% CI (confidence...

  5. Dose Calculations for Radiation Treatment Planning

    Science.gov (United States)

    Mohan, Radhe

    The most common method of treating cancer patients with radiation is externally applied beams of photons generated by linear accelerators, or by high-intensity 60Co radioactive sources. Electron beams generated by linear accelerators also are employed, but not as often as photon beams. Other particles, such as protons, neutrons, pions and heavy ions, have been experimented with, but their use is limited to a few research facilities. For certain types of tumors, internally applied radiation, alone or in combination with external radiation, is suitable. In this chapter, we will confine ourselves to externally applied photon and electron beams only.

  6. Doses to Carotid Arteries After Modern Radiation Therapy for Hodgkin Lymphoma

    DEFF Research Database (Denmark)

    Maraldo, M.V.; Brodin, Nils Patrik; Aznar, Marianne Camille

    2013-01-01

    Hodgkin lymphoma (HL) survivors are at an increased risk of stroke because of carotid artery irradiation. However, for early-stage HL involved node radiation therapy (INRT) reduces the volume of normal tissue exposed to high doses. Here, we evaluate 3-dimensional conformal radiation therapy (3D......-CRT), volumetric-modulated arc therapy (VMAT), and proton therapy (PT) delivered as INRT along with the extensive mantle field (MF) by comparing doses to the carotid arteries and corresponding risk estimates....

  7. Monitoring of radiation exposure and registration of doses

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    The guide defines the concepts relevant to the monitoring of radiation exposure and working conditions and provides guidelines for determining the necessity of monitoring and subsequently organizing it. In addition, instructions are given for reporting doses to the Dose Register of the Finnish Centre for Radiation and Nuclear Safety (STUK). Also the procedures are described for situations leading to exceptional exposures. (10 refs., 1 tab.).

  8. BCC and Childhood Low Dose Radiation

    OpenAIRE

    Arash Beiraghi Toosi; Hamed Shariat Razavi

    2014-01-01

    Skin cancer is a late complication of ionizing radiation. Two skin neoplasms prominent Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC) are the most famous complications of radiotherapy. Basal Cell Carcinoma (BCC) is the most common human malignant neoplasm. Many genetic and environmental factors are involved in its onset. BCC is observed in sun-exposed areas of skin. Some patients with scalp BCC have had a history of scalp radiation for the treatment of tinea capitis in childhood...

  9. Computed Tomography Radiation Dose Reduction: Effect of Different Iterative Reconstruction Algorithms on Image Quality

    NARCIS (Netherlands)

    Willemink, M.J.; Takx, R.A.P.; Jong, P.A. de; Budde, R.P.; Bleys, R.L.; Das, M.; Wildberger, J.E.; Prokop, M.; Buls, N.; Mey, J. de; Leiner, T.; Schilham, A.M.

    2014-01-01

    We evaluated the effects of hybrid and model-based iterative reconstruction (IR) algorithms from different vendors at multiple radiation dose levels on image quality of chest phantom scans.A chest phantom was scanned on state-of-the-art computed tomography scanners from 4 vendors at 4 dose levels

  10. Strategies for Computed Tomography Radiation Dose Reduction in Pediatric Neuroimaging.

    Science.gov (United States)

    Albert, Gregory W; Glasier, Charles M

    2015-08-01

    Radiation exposure from diagnostic imaging is a significant concern, particularly in the care of pediatric patients. Computed tomography (CT) scanning is a significant source of radiation. To demonstrate that diagnostic quality CT images can be obtained while minimizing the effective radiation dose to the patient. In this retrospective cross-sectional study, noncontrast head CT scan data were reviewed, and indications for scans and estimated radiation dose delivered were recorded. The estimated effective radiation dose (EERD) for each CT protocol was reviewed. We identified 251 head CT scans in a single month. Of these, 96 scans were using a low-dose shunt protocol with a mean EERD of 0.82 mSv. The remaining 155 scans were performed using the standard protocol, and the mean EERD was 1.65 mSv. Overall, the EERD was minimized while maintaining diagnostic scan quality. Although replacing a CT with magnetic resonance imaging is ideal to completely avoid ionizing radiation, this is not always practical or preferred. Therefore, it is important to have CT protocols in place that minimize radiation dose without sacrificing diagnostic quality. The protocols in place at our institution could be replicated at other academic and community hospitals and imaging centers.

  11. An Evaluation of Deviation from the International Atomic Energy Agency-International Commission on Radiological Protection Proposed Equation for Calculation of Radiation Dose Rate Emanating from the Patients with Differentiated Thyroid Cancer Undergoing Radioiodine (I-131) Therapy.

    Science.gov (United States)

    Dehkordi, Forough Jafarian; Rasuli, Behrouz; Mahmoud-Pashazadeh, Ali

    2017-01-01

    The main purpose of this study was to investigate dose rate emanating from patients treated with (131)I to evaluate which of the theoretical formulas, inverse-square law (ISL) and International Atomic Energy Agency-International Commission on Radiological Protection (IAEA-ICRP) suggested equation, can provide a sufficiently close approximation of the measured dose rate. Measurements were performed based on the IAEA safety report No. 63 method at 0, 12, 24, and 48 h after administration of radioiodine at a distance of 1 m for 69 patients and for the rest of 67 patients, dose rate was measured at 2, 4, 24, and 48 h at a distance of 2 m. Results revealed that the ISL formula gained better approximation of measured dose rates than the IAEA-ICRP equation with the lesser error. The ISL formula is still more reliable than the novel method of dose calculation in the vicinity of patients. This finding reminded us the prime importance of distance as a radiation protection principle.

  12. Malignant melanoma of the tongue following low-dose radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kalemeris, G.C.; Rosenfeld, L.; Gray, G.F. Jr.; Glick, A.D.

    1985-03-01

    A 47-year-old man had a spindly malignant melanoma of the tongue many years after low-dose radiation therapy for lichen planus. To our knowledge, only 12 melanomas of the tongue have been reported previously, and in none of these was radiation documented.

  13. Assessment of pediatrics radiation dose from routine x-ray ...

    African Journals Online (AJOL)

    Background: Given the fact that children are more sensitive to ionizing radiation than adults,with an increased risk of developing radiation-induced cancer,special care should be taken when they undergo X-ray examinations. The main aim of the current study was to determine Entrance Surface Dose (ESD) to pediatric ...

  14. Methodology for Estimating Radiation Dose Rates to Freshwater Biota Exposed to Radionuclides in the Environment

    Energy Technology Data Exchange (ETDEWEB)

    Blaylock, B.G.

    1993-01-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy's (DOE's) recommended dose rate limit of 0.4 mGy h{sup -1} (1 rad d{sup -1}). A dose rate no greater than 0.4 mGy h{sup -1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE's recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). The literature identifies the developing eggs and young of some species of teleost fish as the most radiosensitive organisms. DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0.1 mGy h{sup -1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic

  15. Measurement of radiation dose in dental radiology.

    Science.gov (United States)

    Helmrot, Ebba; Alm Carlsson, Gudrun

    2005-01-01

    Patient dose audit is an important tool for quality control and it is important to have a well-defined and easy to use method for dose measurements. In dental radiology, the most commonly used dose parameters for the setting of diagnostic reference levels (DRLs) are the entrance surface air kerma (ESAK) for intraoral examinations and dose width product (DWP) for panoramic examinations. DWP is the air kerma at the front side of the secondary collimator integrated over the collimator width and an exposure cycle. ESAK or DWP is usually measured in the absence of the patient but with the same settings of tube voltage (kV), tube current (mA) and exposure time as with the patient present. Neither of these methods is easy to use, and, in addition, DWP is not a risk related quantity. A better method of monitoring patient dose would be to use a dose area product (DAP) meter for all types of dental examinations. In this study, measurements with a DAP meter are reported for intraoral and panoramic examinations. The DWP is also measured with a pencil ionisation chamber and the product of DWP and the height H (DWP x H) of the secondary collimator (measured using film) was compared to DAP. The results show that it is feasible to measure DAP using a DAP meter for both intraoral and panoramic examinations. The DAP is therefore recommended for the setting of DRLs.

  16. The energy influence on the radiation dose of the staff

    OpenAIRE

    CORTEZ JOSE ITALO; Morokina, G.S.

    2015-01-01

    The text of this paper is concerned to the problem of dose control used the sources of gamma and X-ray radiation in the mining industry and others organization of the nondestructive testing. Distinctive features of the resources are the high energy and intensity radiation is the short time delivering testing. The research is devoted to problems of the high energies and high ionization. The influence of radiation used in the industrial purposes, in particular, in nondestructive testing was stu...

  17. A model for low dose effects of low-LET radiation delivered at high dose rates

    Science.gov (United States)

    Schöllnberger, H.; Stewart, R.D.; Mitchel, R.E.J.

    2011-01-01

    In vitro studies show that protective tumour-reducing effects occur for low dose rates (mGy per minute). To account for these phenomena, we have previously developed stochastic and deterministic multi-stage cancer models that include radiation-induced adaptations in DNA repair processes and radical scavenging. Here, these models are extended to account for the induction of radioprotective mechanisms for low doses of low LET radiation delivered at high dose rates. Cellular adaptations in DNA repair are related to temporal changes in the amount of DNA damage in a cell. The combined effects of endogenous DNA damage, background radiation and artificial irradiation are considered. PMID:22318364

  18. Radiation dose assessment for occupationally exposed workers in ...

    African Journals Online (AJOL)

    Background The objective of this study was to assess individual doses received by radiographers, and the scattered radiation dose rate reaching the control panel in X-ray departments of three hospitals in Malawi, in-order to compare them against the internationally recommended limits. Methods Themoluminescent ...

  19. Evaluation of general-purpose collimators against high-resolution collimators with resolution recovery with a view to reducing radiation dose in myocardial perfusion SPECT: A preliminary phantom study.

    Science.gov (United States)

    Armstrong, Ian S; Saint, Kimberley J; Tonge, Christine M; Arumugam, Parthiban

    2017-04-01

    There is a growing focus on reducing radiation dose to patients undergoing myocardial perfusion imaging. This preliminary phantom study aims to evaluate the use of general-purpose collimators with resolution recovery (RR) to allow a reduction in patient radiation dose. Images of a cardiac torso phantom with inferior and anterior wall defects were acquired on a GE Infinia and Siemens Symbia T6 using both high-resolution and general-purpose collimators. Imaging time, a surrogate for administered activity, was reduced between 35% and 40% with general-purpose collimators to match the counts acquired with high-resolution collimators. Images were reconstructed with RR with and without attenuation correction. Two pixel sizes were also investigated. Defect contrast was measured. Defect contrast on general-purpose images was superior or comparable to the high-resolution collimators on both systems despite the reduced imaging time. Infinia general-purpose images required a smaller pixel size to be used to maintain defect contrast, while Symbia T6 general-purpose images did not require a change in pixel size to that used for standard myocardial perfusion SPECT. This study suggests that general-purpose collimators with RR offer a potential for substantial dose reductions while providing similar or better image quality to images acquired using high-resolution collimators.

  20. Flight attendant radiation dose from solar particle events.

    Science.gov (United States)

    Anderson, Jeri L; Mertens, Christopher J; Grajewski, Barbara; Luo, Lian; Tseng, Chih-Yu; Cassinelli, Rick T

    2014-08-01

    Research has suggested that work as a flight attendant may be related to increased risk for reproductive health effects. Air cabin exposures that may influence reproductive health include radiation dose from galactic cosmic radiation and solar particle events. This paper describes the assessment of radiation dose accrued during solar particle events as part of a reproductive health study of flight attendants. Solar storm data were obtained from the National Oceanic and Atmospheric Administration Space Weather Prediction Center list of solar proton events affecting the Earth environment to ascertain storms relevant to the two study periods (1992-1996 and 1999-2001). Radiation dose from exposure to solar energetic particles was estimated using the NAIRAS model in conjunction with galactic cosmic radiation dose calculated using the CARI-6P computer program. Seven solar particle events were determined to have potential for significant radiation exposure, two in the first study period and five in the second study period, and over-lapped with 24,807 flight segments. Absorbed (and effective) flight segment doses averaged 6.5 μGy (18 μSv) and 3.1 μGy (8.3 μSv) for the first and second study periods, respectively. Maximum doses were as high as 440 μGy (1.2 mSv) and 20 flight segments had doses greater than 190 μGy (0.5 mSv). During solar particle events, a pregnant flight attendant could potentially exceed the equivalent dose limit to the conceptus of 0.5 mSv in a month recommended by the National Council on Radiation Protection and Measurements.

  1. Patient radiation exposure in uterine artery embolization of leiomyomata: calculation of organ doses and effective dose

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, S.; Strecker, E.P. [Department of Radiology, Diakonissenkrankenhaus, Diakonissenstrasse 28, 76199, Karlsruhe (Germany); Schultz, F.W.; Zoetelief, J. [Interfaculty Reactor Institute, Medical Physics, Delft University of Technology, 2629 JB, Delft (Netherlands)

    2004-05-01

    The goal of this study was estimation of patient effective dose from uterine artery embolization of leiomyomata. Parameters and data relevant to patient dose were recorded for 33 consecutive procedures. Using Monte Carlo simulation of radiation transport, organ and effective doses were calculated in detail for a subset of five procedures, to estimate the effective dose for all procedures. Mean dose area product was 59.9, median 23.4, and range 8.8-317.5 Gycm{sup 2}. Mean absorbed ovarian dose was calculated as 51 mGy in the five procedures. Using the dose conversion factor estimated from the Monte Carlo simulation for all procedures a mean estimated effective dose of 34 mSv (median 13 mSv, range 5-182 mSv) results, with a tendency to lower values regarding the succession of the procedures. Patients' radiation exposure level is up to twice of that of an abdominal CT examination. Angiographic equipment related dose-reducing features and radiographic technique essentially influence organ doses and effective dose. Consistent application of dose-reducing techniques and awareness of radiation exposure justifies uterine artery embolization as a therapeutic option for the treatment of uterine fibroids. (orig.)

  2. Radiation Dose-Response Relationships and Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Strom, Daniel J.

    2005-07-05

    The notion of a dose-response relationship was probably invented shortly after the discovery of poisons, the invention of alcoholic beverages, and the bringing of fire into a confined space in the forgotten depths of ancient prehistory. The amount of poison or medicine ingested can easily be observed to affect the behavior, health, or sickness outcome. Threshold effects, such as death, could be easily understood for intoxicants, medicine, and poisons. As Paracelsus (1493-1541), the 'father' of modern toxicology said, 'It is the dose that makes the poison.' Perhaps less obvious is the fact that implicit in such dose-response relationships is also the notion of dose rate. Usually, the dose is administered fairly acutely, in a single injection, pill, or swallow; a few puffs on a pipe; or a meal of eating or drinking. The same amount of intoxicants, medicine, or poisons administered over a week or month might have little or no observable effect. Thus, before the discovery of ionizing radiation in the late 19th century, toxicology ('the science of poisons') and pharmacology had deeply ingrained notions of dose-response relationships. This chapter demonstrates that the notion of a dose-response relationship for ionizing radiation is hopelessly simplistic from a scientific standpoint. While useful from a policy or regulatory standpoint, dose-response relationships cannot possibly convey enough information to describe the problem from a quantitative view of radiation biology, nor can they address societal values. Three sections of this chapter address the concepts, observations, and theories that contribute to the scientific input to the practice of managing risks from exposure to ionizing radiation. The presentation begins with irradiation regimes, followed by responses to high and low doses of ionizing radiation, and a discussion of how all of this can inform radiation risk management. The knowledge that is really needed for prediction of

  3. Radiation dose estimation of patients undergoing lumbar spine radiography

    OpenAIRE

    Prince Kwabena Gyekye; Adu Simon; Emi-Reynolds Geoffrey; Yeboah Johnson; Inkoom Stephen; Cynthia Kaikor Engmann; Wotorchi-Gordon Samuel

    2013-01-01

    Radiation dose to organs of 100 adult patients undergoing lumbar spine (LS) radiography at a University Hospital have been assessed. Free in air kerma measurement using an ionization chamber was used for the patient dosimetry. Organ and effective dose to the patients were estimated using PCXMC (version 1.5) software. The organs that recorded significant dose due to LS radiography were lungs, stomach, liver, adrenals, kidney, pancreas, spleen, galbladder, and the heart. It was observed that th...

  4. Effective UV radiation dose in polyethylene exposed to weather

    Science.gov (United States)

    González-Mota, R.; Soto-Bernal, J. J.; Rosales-Candelas, I.; Calero Marín, S. P.; Vega-Durán, J. T.; Moreno-Virgen, R.

    2009-09-01

    In this work we quantified the effective UV radiation dose in orange and colorless polyethylene samples exposed to weather in the city of Aguascalientes, Ags. Mexico. The spectral distribution of solar radiation was calculated using SMART 2.9.5.; the samples absorption properties were measured using UV-Vis spectroscopy and the quantum yield was calculated using samples reflectance properties. The determining factor in the effective UV dose is the spectral distribution of solar radiation, although the chemical structure of materials is also important.

  5. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, Jordan [Advanced Residential Integrated Energy Solutions Collaborative, New York, NY (United States); Ansanelli, Eric [Advanced Residential Integrated Energy Solutions Collaborative, New York, NY (United States)

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market.

  6. Dose received by radiation workers in Australia, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Morris, N.D.

    1994-07-01

    Exposure to radiation can cause genetic defects or cancer. People who use sources of radiation as part of their employment are potentially at a greater risk than others owing to the possibility of their being continually exposed to small radiation doses over a long period. In Australia, the National Health and Medical Research Council has established radiation protection standards and set annual effective dose limits for radiation workers in order to minimise the chance of adverse effects occurring. These standards are based on the the recommendations of the International Commission on Radiological Protection (ICRP 1990). In order to ensure that the prescribed limits are not exceeded and to ensure that doses are kept to a minimum, some sort of monitoring is necessary. The primary purpose of this report is to provide data on the distribution of effective doses for different occupational categories of radiation worker in Australia. The total collective effective dose was found to be of the order of 4.9 Sv for a total of 34750 workers. 9 refs., 16 tabs., 6 figs.

  7. Therapeutic effects of low radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Trott, K.R. (Dept. of Radiation Biology, St. Bartholomew' s Medical College, London (United Kingdom))

    1994-01-01

    This editorial explores the scientific basis of radiotherapy with doses of < 1 Gy for various non-malignant conditions, in particular dose-effect relationships, risk-benefit considerations and biological mechanisms. A review of the literature, particularly clinical and experimental reports published more than 50 years ago was conducted to clarify the following problems. 1. The dose-response relationships for the therapeutic effects on three groups of conditions: non-malignant skin disease, arthrosis and other painful degenerative joint disorders and anti-inflammatory radiotherapy; 2. risks after radiotherapy and after the best alternative treatments; 3. the biological mechanisms of the different therapeutic effects. Radiotherapy is very effective in all three groups of disease. Few dose-finding studies have been performed, all demonstrating that the optimal doses are considerable lower than the generally recommended doses. In different conditions, risk-benefit analysis of radiotherapy versus the best alternative treatment yields very different results: whereas radiotherapy for acute postpartum mastitis may not be justified any more, the risk-benefit ratio of radiotherapy of other conditions and particularly so in dermatology and some anti-inflammatory radiotherapy appears to be more favourable than the risk-benefit ratio of the best alternative treatments. Radiotherapy can be very effective treatment for various non-malignant conditions such as eczema, psoriasis, periarthritis humeroscapularis, epicondylitis, knee arthrosis, hydradenitis, parotitis and panaritium and probably be associated with less acute and long-term side effects than similarly effective other treatments. Randomized clinical studies are required to find the optimal dosage which, at present, may be unnecessarily high.

  8. Molecular targets for radioprotection by low dose radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hang Rhan; Lee, Yoon Jin; Cho, Chul Koo; Lee, Su Jae; Bae, Sang woo; Lee, Yun Sil [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2004-07-01

    Adaptive response is a reduced effect from a higher challenging dose of a stressor after a smaller inducing dose had been applied a few hrs earlier. Radiation induced fibrosarcoma (RIF) cells did not show such an adaptive response, i.e. a reduced effect from a higher challenging dose (2 Gy) of a radiation after a priming dose (1 cGy) had been applied 4 or 7 hrs earlier, but its thermoresistant clone (TR) did. Since inducible HSP70 and HSP25 expressions were different between these two cell lines, the role of inducible HSP70 and HSP25 in adaptive response was examined. When inducible hsp70 or hsp25 genes were transfected to RIF cells, radioresistance in clonogenic survival and reduction of apoptosis was detected. The adaptive response was also acquired in these two cell lines, and inducible hsp70 transfectant showed more pronounced adaptive response than hsp25 transfectant. From these results, inducible HSP70 and HSP25 are at least partly responsible for the induction of adaptive response in these cells. Moreover, when inducible HSP70 or HSP25 genes were transfected to RIF cells, coregulation of each gene was detected and heat shock factor (HSF) was found to be responsible for these phenomena. In continuation of our earlier study on the involvement of heat shock protein (HSP) 25 and HSP70 in the induction of adaptive response, we have now examined the involvement of these proteins in the induction of the adaptive response, using an animal model system. C57BL6 mice were irradiated with 5 cGy of gamma radiation 3 times for a week (total of 15cGy) and a high challenge dose (6Gy) was given on the day following the last low dose irradiation. Survival rate of the low dose pre-irradiated mice was increased to 30%. Moreover, high dose-mediated induction of apoptosis was also reduced by low dose pre-irradiation. To elucidate any link existing between HSP and induction of the adaptive response, reverse transcriptase (RT)-polymerase chain reaction (PCR) analysis was performed

  9. A CONCEPTUAL FRAMEWORK FOR MANAGING RADIATION DOSE TO PATIENTS IN DIAGNOSTIC RADIOLOGY USING REFERENCE DOSE LEVELS.

    Science.gov (United States)

    Almén, Anja; Båth, Magnus

    2016-06-01

    The overall aim of the present work was to develop a conceptual framework for managing radiation dose in diagnostic radiology with the intention to support optimisation. An optimisation process was first derived. The framework for managing radiation dose, based on the derived optimisation process, was then outlined. The outset of the optimisation process is four stages: providing equipment, establishing methodology, performing examinations and ensuring quality. The optimisation process comprises a series of activities and actions at these stages. The current system of diagnostic reference levels is an activity in the last stage, ensuring quality. The system becomes a reactive activity only to a certain extent engaging the core activity in the radiology department, performing examinations. Three reference dose levels-possible, expected and established-were assigned to the three stages in the optimisation process, excluding ensuring quality. A reasonably achievable dose range is also derived, indicating an acceptable deviation from the established dose level. A reasonable radiation dose for a single patient is within this range. The suggested framework for managing radiation dose should be regarded as one part of the optimisation process. The optimisation process constitutes a variety of complementary activities, where managing radiation dose is only one part. This emphasises the need to take a holistic approach integrating the optimisation process in different clinical activities. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. The Effect of High Dose Radioiodine Therapy on Formation of Radiation Retinopathy During Thyroid Cancer Treatment

    OpenAIRE

    Tülay Kaçar Güvel; Sezer Özkan; Müge Öner Tamam

    2014-01-01

    Objective: Non-thyroidal complication of high-dose radioiodine therapy for thyroid carcinoma might cause salivary and lacrimal gland dysfunction, which may be transient or permanent in a dose-dependent manner. However, radiation retinopathy complicating 131I therapy, has not been previously well characterized. The aim of this study was to evaluate the extent of retinal damage among patients who had received high doses of radioiodine treatment. Methods: Forty eyes of 20 patients (3 male, 17 fe...

  11. Low-Dose Radiation Cataract and Genetic Determinants of Radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Kleiman, Norman Jay [Columbia University

    2013-11-30

    The lens of the eye is one of the most radiosensitive tissues in the body. Ocular ionizing radiation exposure results in characteristic, dose related, progressive lens changes leading to cataract formation. While initial, early stages of lens opacification may not cause visual disability, the severity of such changes progressively increases with dose until vision is impaired and cataract extraction surgery may be required. Because of the transparency of the eye, radiation induced lens changes can easily be followed non-invasively over time. Thus, the lens provides a unique model system in which to study the effects of low dose ionizing radiation exposure in a complex, highly organized tissue. Despite this observation, considerable uncertainties remain surrounding the relationship between dose and risk of developing radiation cataract. For example, a growing number of human epidemiological findings suggest significant risk among various groups of occupationally and accidentally exposed individuals and confidence intervals that include zero dose. Nevertheless, questions remain concerning the relationship between lens opacities, visual disability, clinical cataract, threshold dose and/or the role of genetics in determining radiosensitivity. Experimentally, the response of the rodent eye to radiation is quite similar to that in humans and thus animal studies are well suited to examine the relationship between radiation exposure, genetic determinants of radiosensitivity and cataractogenesis. The current work has expanded our knowledge of the low-dose effects of X-irradiation or high-LET heavy ion exposure on timing and progression of radiation cataract and has provided new information on the genetic, molecular, biochemical and cell biological features which contribute to this pathology. Furthermore, findings have indicated that single and/or multiple haploinsufficiency for various genes involved in DNA repair and cell cycle checkpoint control, such as Atm, Brca1 or Rad9

  12. Radiation dose due to radon and thoron progeny inhalation in high-level natural radiation areas of Kerala, India.

    Science.gov (United States)

    Omori, Yasutaka; Tokonami, Shinji; Sahoo, Sarata Kumar; Ishikawa, Tetsuo; Sorimachi, Atsuyuki; Hosoda, Masahiro; Kudo, Hiromi; Pornnumpa, Chanis; Nair, Raghu Ram K; Jayalekshmi, Padmavaty Amma; Sebastian, Paul; Akiba, Suminori

    2017-03-20

    In order to evaluate internal exposure to radon and thoron, concentrations for radon, thoron, and thoron progeny were measured for 259 dwellings located in high background radiation areas (HBRAs, outdoor external dose: 3-5 mGy y(-1)) and low background radiation areas (control areas, outdoor external dose: 1 mGy y(-1)) in Karunagappally Taluk, Kerala, India. The measurements were conducted using passive-type radon-thoron detectors and thoron progeny detectors over two six-month measurement periods from June 2010 to June 2011. The results showed no major differences in radon and thoron progeny concentrations between the HBRAs and the control areas. The geometric mean of the annual effective dose due to radon and thoron was calculated as 0.10 and 0.44 mSv, respectively. The doses were small, but not negligible compared with the external dose in the two areas.

  13. Exposure of luminous marine bacteria to low-dose gamma-radiation.

    Science.gov (United States)

    Kudryasheva, N S; Petrova, A S; Dementyev, D V; Bondar, A A

    2017-04-01

    The study addresses biological effects of low-dose gamma-radiation. Radioactive 137Cs-containing particles were used as model sources of gamma-radiation. Luminous marine bacterium Photobacterium phosphoreum was used as a bioassay with the bioluminescent intensity as the physiological parameter tested. To investigate the sensitivity of the bacteria to the low-dose gamma-radiation exposure (≤250 mGy), the irradiation conditions were varied as follows: bioluminescence intensity was measured at 5, 10, and 20°С for 175, 100, and 47 h, respectively, at different dose rates (up to 4100 μGy/h). There was no noticeable effect of gamma-radiation at 5 and 10°С, while the 20°С exposure revealed authentic bioluminescence inhibition. The 20°С results of gamma-radiation exposure were compared to those for low-dose alpha- and beta-radiation exposures studied previously under comparable experimental conditions. In contrast to ionizing radiation of alpha and beta types, gamma-emission did not initiate bacterial bioluminescence activation (adaptive response). As with alpha- and beta-radiation, gamma-emission did not demonstrate monotonic dose-effect dependencies; the bioluminescence inhibition efficiency was found to be related to the exposure time, while no dose rate dependence was found. The sequence analysis of 16S ribosomal RNA gene did not reveal a mutagenic effect of low-dose gamma radiation. The exposure time that caused 50% bioluminescence inhibition was suggested as a test parameter for radiotoxicity evaluation under conditions of chronic low-dose gamma irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Errors and Uncertainties in Dose Reconstruction for Radiation Effects Research

    Energy Technology Data Exchange (ETDEWEB)

    Strom, Daniel J.

    2008-04-14

    Dose reconstruction for studies of the health effects of ionizing radiation have been carried out for many decades. Major studies have included Japanese bomb survivors, atomic veterans, downwinders of the Nevada Test Site and Hanford, underground uranium miners, and populations of nuclear workers. For such studies to be credible, significant effort must be put into applying the best science to reconstructing unbiased absorbed doses to tissues and organs as a function of time. In many cases, more and more sophisticated dose reconstruction methods have been developed as studies progressed. For the example of the Japanese bomb survivors, the dose surrogate “distance from the hypocenter” was replaced by slant range, and then by TD65 doses, DS86 doses, and more recently DS02 doses. Over the years, it has become increasingly clear that an equal level of effort must be expended on the quantitative assessment of uncertainty in such doses, and to reducing and managing uncertainty. In this context, this paper reviews difficulties in terminology, explores the nature of Berkson and classical uncertainties in dose reconstruction through examples, and proposes a path forward for Joint Coordinating Committee for Radiation Effects Research (JCCRER) Project 2.4 that requires a reasonably small level of effort for DOSES-2008.

  15. Evaluation of quality characteristics and functional properties of mechanically deboned chicken meats treated with different dose rates of ionizing radiation and use of antioxidants; Avaliacao de caracteristicas de qualidade e propriedades funcionais da carne mecanicamente separada de frango tratada com diferentes taxas de dose de radiacao ionizante e uso de antioxidantes

    Energy Technology Data Exchange (ETDEWEB)

    Brito, Poliana de Paula

    2012-07-01

    The Mechanically Deboned chicken meat (MDCM) is used in traditional meat products, in greater proportion in those emulsified, replacing meat raw materials more expensive. The raw material can have high MDCM the microbial load, as a result of contamination during processing or failure during the evisceration. The irradiation process is accepted as one of the most effective technologies when compared to conventional techniques of preservation, to reduce contamination of pathogens and spoilage. However, little information is available about the use and effects of different dose rates of ionizing radiation processing. Irradiation causes chemical changes in food, a major cause of deterioration of quality of raw or cooked meat products during refrigerated storage, frozen. The objective of this study was to evaluate the effects of different dose rates of ionizing radiation on the production of Thiobarbituric Acid Reactive Substances (TBARS), color, microbiological and sensory characteristics of mechanically deboned chicken added or without added antioxidants, during the cold storage and evaluation of functional properties. The results showed that among the tested dose rates using cobalt-60 source, dose rate of 4.04 kGy.h-1 was the best for processing MDCM. Furthermore, the use of the combination of rosemary antioxidant and α-tocopherol were able to reduce lipid oxidation generated by irradiation of the samples, showed a synergistic effect to the processing with ionizing radiation in reduction of psychrotrophic bacteria count and contributed to a better sensory quality. The use of radiation in the processing FDMI did not adversely affect the functional properties studied. (author)

  16. Radiation dose and radiation protection principle awareness: a survey among Nigerian paediatricians.

    Science.gov (United States)

    Famurewa, O C; Obiajunwa, P O; Elusiyan, J B; Ibitoye, B O

    2014-03-01

    This study is aimed at determining the knowledge of Paediatricians in Nigeria about the basic principle of radiation protection ALARA (As Low As Reasonably Achievable) and their knowledge of the radiation doses that children receive during some common radiological procedures. Two hundred and fifty questionnaires were circulated among paediatricians at the 2012 annual Paediatricians' Association of Nigeria Conference. The questionnaires contain 10 questions designed to asses the pediatricians' general knowledge on : ionising radiation and the risks, doses children receive during some common radiological procedures and awareness of the radiation protection principle, ALARA ( As Low As Reasonably Achievable). Of the 162 Paediatricians that participated, 69% named at least one non medical source of ionising radiation, 54.9% would not recommend CXR to screen an apparently healthy child for tuberculosis and 87% believe that children are at greater risk of adverse effects of ionising radiation. For dose estimation, 51.9% and 51.2% of the paediatricians underestimated doses received during Cranial and abdominal computerised tomography respectively while 13.6% and 37% respectively erroneously believed that abdominal ultrasound and brain magnetic resonance imaging utilise ionising radiation. 13.6% gave the correct meaning of the Acronym ALARA. The Paediatricians' knowledge about the basic principle of radiation protection ALARA and the doses that children receive during some common radiological procedures is poor. There is need to ensure adequate training on radiation hazards and protection at all levels of medical education.

  17. Toxicity bioassay in mice exposed to low dose-rate radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joog Sun; Gong, Eun Ji; Heo, Kyu; Yang, Kwang Mo [Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan (Korea, Republic of)

    2013-04-15

    The systemic effect of radiation increases in proportion to the dose amount and rate. The association between accumulated radiation dose and adverse effects, which is derived according to continuous low dose-rate radiation exposure, is not clearly elucidated. Our previous study showed that low dose-rate radiation exposure did not cause adverse effects in BALB/c mice at dose levels of ≤2 Gy, but the testis weight decreased at a dose of 2 Gy. In this study, we studied the effects of irradiation at the low dose rate (3.49 mGy/h) in the testes of C57BL/6 mice. Mice exposed to a total dose of 0.02, 0.2, and 2 Gy were found to be healthy and did not show any significant changes in body weight and peripheral blood components. However, mice irradiated with a dose of 2 Gy had significantly decreased testis weight. Further, histological studies and sperm evaluation also demonstrated changes consistent with the findings of decreased testis weight. In fertile patients found to have arrest of sperm maturation, the seminiferous tubules lack the DNMT1 and HDAC1 protein. The decrease of DNMT1 and HDAC1 in irradiated testis may be the part of the mechanism via which low dose-rate irradiation results in teticular injury. In conclusion, despite a low dose-rate radiation, our study found that when mice testis were irradiated with 2 Gy at 3.49 mGy/h dose rate, there was significant testicular and sperm damage with decreased DNMT1 and HDAC1 expression.

  18. Design study on dose evaluation method for employees at severe accident

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Yoshitaka; Irie, Takashi; Kohriyama, Tamio [Institute of Nuclear Safety Systems Inc., Mihama, Fukui (Japan); Kudo, Seiichi [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Nishimura, Kazuya [Computer Software Development Co., Ltd., Tokyo (Japan)

    2001-09-01

    When we assume a severe accident in a nuclear power plant, it is required for rescue activity in the plant, accident management, repair work of failed parts and evaluation of employees to obtain radiation dose rate distribution or map in the plant and estimated dose value for the above works. However it might be difficult to obtain them accurately along the progress of the accident, because radiation monitors are not always installed in the areas where the accident management is planned or the repair work is thought for safety-related equipments. In this work, we analyzed diffusion of radioactive materials in case of a severe accident in a pressurized water reactor plant, investigated a method to obtain radiation dose rate in the plant from estimated radioactive sources, made up a prototype analyzing system by modeling a specific part of components and buildings in the plant from this design study on dose evaluation method for employees at severe accident, and then evaluated its availability. As a result, we obtained the followings: (1) A new dose evaluation method was established to predict the radiation dose rate in any point in the plant during a severe accident scenario. (2) This evaluation of total dose including moving route and time for the accident management and the repair work is useful for estimating radiation dose limit for these actions of the employees. (3) The radiation dose rate map is effective for identifying high radiation areas and for choosing a route with lower radiation dose rate. (author)

  19. Methods for estimating radiation doses received by commercial aircrew.

    Science.gov (United States)

    Lantos, Pierre; Fuller, Nicolas; Bottollier-Depois, Jean-François

    2003-07-01

    Radiation doses received onboard aircraft are monitored in Europe to protect aircrew in accordance with a European Union directive. The French Aviation Authorities have developed a system called SIEVERT, using calculation codes to monitor effective radiation doses. For the galactic cosmic ray component, a 3-D world map of effective dose rates is computed using available operational codes. Detailed flight plans are used to ensure sufficient precision. For the solar particle event component, a semi-empirical model called SiGLE has been developed to calculate a time-dependent map of effective dose rates in the course of the event. SiGLE is based on particle transport code results and measurements during solar particle events onboard Concorde airplanes. We present a comparison of the calculated effective radiation dose and measured dose equivalent for various flights onboard Air France aircraft. The agreement is within 15%, which is about the precision of the state-of-the-art dosimetric measurements. Meteorological effects on the dose calculation appear to be negligible. Preliminary results based on solar particle events observed since 1942 with ionization chambers and neutron monitors are given. The present analysis shows that for the galactic cosmic ray component, monthly world maps based on neutron monitor observations are sufficient to ensure a precision of about 20% on the dose estimate for each flight. For the past 40 yr, according to the model SiGLE, none of the solar events has given an effective radiation dose larger than 1 mSv for flights on the most exposed routes.

  20. Effect of Bismuth Breast Shielding on Radiation Dose and Image Quality in Coronary CT Angiography

    Science.gov (United States)

    Einstein, Andrew J.; Elliston, Carl D.; Groves, Daniel W.; Cheng, Bin; Wolff, Steven D.; Pearson, Gregory D. N.; Peters, M. Robert; Johnson, Lynne L.; Bokhari, Sabahat; Johnson, Gary W.; Bhatia, Ketan; Pozniakoff, Theodore; Brenner, David J.

    2011-01-01

    Background Coronary computed tomographic angiography (CCTA) is associated with high radiation dose to the female breasts. Bismuth breast shielding offers the potential to significantly reduce dose to the breasts and nearby organs, but the magnitude of this reduction and its impact on image quality and radiation dose have not been evaluated. Methods Radiation doses from CCTA to critical organs were determined using metal-oxide-semiconductor field-effect transistors positioned in a customized anthropomorphic whole-body dosimetry verification phantom. Image noise and signal were measured in regions of interest (ROIs) including the coronary arteries. Results With bismuth shielding, breast radiation dose was reduced 46–57% depending on breast size and scanning technique, with more moderate dose reduction to the heart, lungs, and esophagus. However, shielding significantly decreased image signal (by 14.6 HU) and contrast (by 28.4 HU), modestly but significantly increased image noise in ROIs in locations of coronary arteries, and decreased contrast-to-noise ratio by 20.9%.. Conclusions While bismuth breast shielding can significantly decrease radiation dose to critical organs, it is associated with an increase in image noise, decrease in contrast-to-noise, and changes tissue attenuation characteristics in the location of the coronary arteries. PMID:22068687

  1. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, J. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States); Ansanelli, E. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States)

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market. In this project, the ARIES team sought to better understand the current usage of TRVs by key market players in steam and hot water heating and to conduct limited experiments on the effectiveness of new and old TRVs as a means of controlling space temperatures and reducing heating fuel consumption. The project included a survey of industry professionals, a field experiment comparing old and new TRVs, and cost-benefit modeling analysis using BEopt™ (Building Energy Optimization software).

  2. Offsite radiation doses summarized from Hanford environmental monitoring reports for the years 1957-1984. [Contains glossary

    Energy Technology Data Exchange (ETDEWEB)

    Soldat, J.K.; Price, K.R.; McCormack, W.D.

    1986-02-01

    Since 1957, evaluations of offsite impacts from each year of operation have been summarized in publicly available, annual environmental reports. These evaluations included estimates of potential radiation exposure to members of the public, either in terms of percentages of the then permissible limits or in terms of radiation dose. The estimated potential radiation doses to maximally exposed individuals from each year of Hanford operations are summarized in a series of tables and figures. The applicable standard for radiation dose to an individual for whom the maximum exposure was estimated is also shown. Although the estimates address potential radiation doses to the public from each year of operations at Hanford between 1957 and 1984, their sum will not produce an accurate estimate of doses accumulated over this time period. The estimates were the best evaluations available at the time to assess potential dose from the current year of operation as well as from any radionuclides still present in the environment from previous years of operation. There was a constant striving for improved evaluation of the potential radiation doses received by members of the public, and as a result the methods and assumptions used to estimate doses were periodically modified to add new pathways of exposure and to increase the accuracy of the dose calculations. Three conclusions were reached from this review: radiation doses reported for the years 1957 through 1984 for the maximum individual did not exceed the applicable dose standards; radiation doses reported over the past 27 years are not additive because of the changing and inconsistent methods used; and results from environmental monitoring and the associated dose calculations reported over the 27 years from 1957 through 1984 do not suggest a significant dose contribution from the buildup in the environment of radioactive materials associated with Hanford operations.

  3. Radiation dose study in nuclear medicine using GATE

    Science.gov (United States)

    Aguwa, Kasarachi

    Dose as a result of radiation exposure is the notion generally used to disclose the imparted energy in a volume of tissue to a potential biological effect. The basic unit defined by the international system of units (SI system) is the radiation absorbed dose, which is expressed as the mean imparted energy in a mass element of the tissue known as "gray" (Gy) or J/kg. The procedure for ascertaining the absorbed dose is complicated since it involves the radiation transport of numerous types of charged particles and coupled photon interactions. The most precise method is to perform a full 3D Monte Carlo simulation of the radiation transport. There are various Monte Carlo toolkits that have tool compartments for dose calculations and measurements. The dose studies in this thesis were performed using the GEANT4 Application for Emission Tomography (GATE) software (Jan et al., 2011) GATE simulation toolkit has been used extensively in the medical imaging community, due to the fact that it uses the full capabilities of GEANT4. It also utilizes an easy to-learn GATE macro language, which is more accessible than learning the GEANT4/C++ programming language. This work combines GATE with digital phantoms generated using the NCAT (NURBS-based cardiac-torso phantom) toolkit (Segars et al., 2004) to allow efficient and effective estimation of 3D radiation dose maps. The GATE simulation tool has developed into a beneficial tool for Monte Carlo simulations involving both radiotherapy and imaging experiments. This work will present an overview of absorbed dose of common radionuclides used in nuclear medicine and serve as a guide to a user who is setting up a GATE simulation for a PET and SPECT study.

  4. Radiation dose reduction in parasinus CT by spectral shaping

    Energy Technology Data Exchange (ETDEWEB)

    May, Matthias S.; Brand, Michael; Lell, Michael M.; Uder, Michael; Wuest, Wolfgang [University Hospital Erlangen, Department of Radiology, Erlangen (Germany); Sedlmair, Martin; Allmendinger, Thomas [Siemens Healthcare GmbH, Forchheim (Germany)

    2017-02-15

    Spectral shaping aims to narrow the X-ray spectrum of clinical CT. The aim of this study was to determine the image quality and the extent of radiation dose reduction that can be achieved by tin prefiltration for parasinus CT. All scans were performed with a third generation dual-source CT scanner. A study protocol was designed using 100 kV tube voltage with tin prefiltration (200 mAs) that provides image noise levels comparable to a low-dose reference protocol using 100 kV without spectral shaping (25 mAs). One hundred consecutive patients were prospectively enrolled and randomly assigned to the study or control group. All patients signed written informed consent. The study protocol was approved by the local Institutional Review Board and applies to the HIPAA. Subjective and objective image quality (attenuation values, image noise, and contrast-to-noise ratio (CNR)) were assessed. Radiation exposure was assessed as volumetric CT dose index, and effective dose was estimated. Mann-Whitney U test was performed for radiation exposure and for image noise comparison. All scans were of diagnostic image quality. Image noise in air, in the retrobulbar fat, and in the eye globe was comparable between both groups (all p > 0.05). CNR{sub eye} {sub globe/air} did not differ significantly between both groups (p = 0.7). Radiation exposure (1.7 vs. 2.1 mGy, p < 0.01) and effective dose (0.055 vs. 0.066 mSv, p < 0.01) were significantly reduced in the study group. Radiation dose can be further reduced by 17% for low-dose parasinus CT by tin prefiltration maintaining diagnostic image quality. (orig.)

  5. Radiation-induced biomarkers for the detection and assessment of absorbed radiation doses

    Directory of Open Access Journals (Sweden)

    Sudha Rana

    2010-01-01

    Full Text Available Radiation incident involving living organisms is an uncommon but a very serious situation. The first step in medical management including triage is high-throughput assessment of the radiation dose received. Radiation exposure levels can be assessed from viability of cells, cellular organelles such as chromosome and different intermediate metabolites. Oxidative damages by ionizing radiation result in carcinogenesis, lowering of the immune response and, ultimately, damage to the hematopoietic system, gastrointestinal system and central nervous system. Biodosimetry is based on the measurement of the radiation-induced changes, which can correlate them with the absorbed dose. Radiation biomarkers such as chromosome aberration are most widely used. Serum enzymes such as serum amylase and diamine oxidase are the most promising biodosimeters. The level of gene expression and protein are also good biomarkers of radiation.

  6. Acute Hematological Effects in Mice Exposed to the Expected Doses, Dose-rates, and Energies of Solar Particle Event-like Proton Radiation

    Science.gov (United States)

    Sanzari, Jenine K.; Cengel, Keith A.; Wan, X. Steven; Rusek, Adam; Kennedy, Ann R.

    2014-01-01

    NASA has funded several projects that have provided evidence for the radiation risk in space. One radiation concern arises from solar particle event (SPE) radiation, which is composed of energetic electrons, protons, alpha particles and heavier particles. SPEs are unpredictable and the accompanying SPE radiation can place astronauts at risk of blood cell death, contributing to a weakened immune system and increased susceptibility to infection. The doses, dose rates, and energies of the proton radiation expected to occur during a SPE have been simulated at the NASA Space Radiation Laboratory, Brookhaven National Laboratory, delivering total body doses to mice. Hematological values were evaluated at acute time points, up to 24 hrs. post-radiation exposure. PMID:25202654

  7. Dose assessment due to terrestrial gamma radiation in Ibadan ...

    African Journals Online (AJOL)

    The activities of primordial radionuclides in surface soil at Ibadan, South-Western Nigeria have been measured with a 7.6cm x 7.6cm NaI(TL) detector. The mean absorbed dose rate, annual effective dose and the collective effective dose at Ibadan were evaluated from measurement of 40K; 238U; 232Th activities and their ...

  8. Computed radiography in scoliosis. Diagnostic information and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, A. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Jonsson, K. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Eklund, K. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Holje, G. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden); Pettersson, H. [Dept. of Diagnostic Radiology, Univ. Hospital, Lund (Sweden)

    1995-07-01

    The diagnostic information and radiation dose in scoliosis examinations performed with air-gap technique using stimulable phosphor imaging plates were determined in a prospective study. Overlapping p.a. images of the thoracic and lumbar spine in 9 patients were obtained with 4 different exposure settings according to patient size. Equal exposure settings were used for the 2 images. Two images of 18 were judged inferior in depicting the landmarks of scoliosis measurement, requiring re-exposure. Sixteen images were judged of adequate or good quality. The mean entrance doses in the central beam for the 4 patient groups were in the interval of 0.05 to 0.12 mGy for both images. The skin doses on the breasts were in the range of 0.00 to 0.03 mGy. The presented technique thus results in a low radiation dose with sufficient diagnostic information in radiography of scoliosis. (orig.).

  9. Sensors of absorbed dose of ionizing radiation based on mosfet

    Directory of Open Access Journals (Sweden)

    Perevertaylo V. L.

    2010-10-01

    Full Text Available The requirements to technology and design of p-channel and n-channel MOS transistors with a thick oxide layer designed for use in the capacity of integral dosimeters of absorbed dose of ionizing radiation are defined. The technology of radiation-sensitive MOS transistors with a thick oxide in the p-channel and n-channel version is created.

  10. Efficacy of high-pitch CT protocols for radiation dose reduction.

    Science.gov (United States)

    Guberina, N; Lechel, U; Forsting, M; Ringelstein, A

    2016-12-01

    Various strategies have been developed to reduce radiation exposure of patients in CT examinations. The aim of this study was to evaluate the efficacy of high pitch in representative CT protocols examining lung embolism. We performed thermoluminescence measurements with an anthropomorphic phantom exposing it to CT algorithms for lung embolism in a 128-multislice, dual-source CT scanner: a standard CT protocol (sCT) and a CT protocol with a high pitch (+ F). Radiation doses for both CT algorithms were compared and the dose reduction potential of high pitch for individual organs was evaluated. As expected, the  +F mode reduced the effective dose and organ doses in the primary beam of radiation (namely, lung, bone marrow, heart, breast, skin and skeleton) compared with sCT by up to 52% for an equivalent image quality. On the contrary, for organs at the margin of the primary beam (thymus, thyroid, liver, pancreas, kidneys, colon and small intestine), the  +F mode reduced effective radiation doses by only 0-30%, compared with sCT. The dose reduction potential of the  +F mode greatly depends on the position of the organ in the scan field. While for organs in the primary beam  + F leads to a considerable dose reduction, it is less effective for tissues at the margin of the scanned area.

  11. Management of pediatric radiation dose using Agfa computed radiography

    Energy Technology Data Exchange (ETDEWEB)

    Schaetzing, R. [Agfa Corp., Greenville, SC (United States)

    2004-10-01

    Radiation dose to patients and its management have become important considerations in modern radiographic imaging procedures, but they acquire particular significance in the imaging of children. Because of their longer life expectancy, children exposed to radiation are thought to have a significantly increased risk of radiation-related late sequelae compared to adults first exposed to radiation later in life. Therefore, current clinical thinking dictates that dose in pediatric radiography be minimized, while simultaneously ensuring sufficient diagnostic information in the image, and reducing the need for repeat exposures. Dose management obviously starts with characterization and control of the exposure technique. However, it extends farther through the imaging chain to the acquisition system, and even to the image processing techniques used to optimize acquired images for display. Further, other factors, such as quality control procedures and the ability to handle special pediatric procedures, like scoliosis exams, also come into play. The need for dose management in modern radiography systems has spawned a variety of different solutions, some of which are similar across different manufacturers, and some of which are unique. This paper covers the techniques used in Agfa Computed Radiography (CR) systems to manage dose in a pediatric environment. (orig.)

  12. Radiation dose associated with CT-guided drain placement for pediatric patients

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Cody J.; Isaacson, Ari J.; Fordham, Lynn Ansley; Ivanovic, Marija; Dixon, Robert G. [University of North Carolina at Chapel Hill, Department of Radiology, UNC Health Care, Chapel Hill, NC (United States); Taylor, J.B. [University of North Carolina at Chapel Hill, Environment, Health and Safety, Chapel Hill, NC (United States)

    2017-05-15

    To date, there are limited radiation dose data on CT-guided procedures in pediatric patients. Our goal was to quantify the radiation dose associated with pediatric CT-guided drain placement and follow-up drain evaluations in order to estimate effective dose. We searched the electronic medical record and picture archiving and communication system (PACS) to identify all pediatric (<18 years old) CT-guided drain placements performed between January 2008 and December 2013 at our institution. We compiled patient data and radiation dose information from CT-guided drain placements as well as pre-procedural diagnostic CTs and post-procedural follow-up fluoroscopic abscess catheter injections (sinograms). Then we converted dose-length product, fluoroscopy time and number of acquisitions to effective doses using Monte Carlo simulations and age-appropriate conversion factors based on annual quality-control testing. Fifty-two drainages were identified with mean patient age of 11.0 years (5 weeks to 17 years). Most children had diagnoses of appendicitis (n=23) or inflammatory bowel disease (n=11). Forty-seven patients had diagnostic CTs, with a mean effective dose of 7.3 mSv (range 1.1-25.5 mSv). Drains remained in place for an average of 16.9 days (range 0-75 days), with an average of 0.9 (0-5) sinograms per patient in follow-up. The mean effective dose for all drainages and follow-up exams was 5.3 mSv (0.7-17.1) and 62% (32/52) of the children had effective doses less than 5 mSv. The majority of pediatric patients who have undergone CT-guided drain placements at our institution have received total radiation doses on par with diagnostic ranges. This information could be useful when describing the dose of radiation to parents and providers when CT-guided drain placement is necessary. (orig.)

  13. Application of maximum values for radiation exposure and principles for the calculation of radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The guide sets out the mathematical definitions and principles involved in the calculation of the equivalent dose and the effective dose, and the instructions concerning the application of the maximum values of these quantities. further, for monitoring the dose caused by internal radiation, the guide defines the limits derived from annual dose limits (the Annual Limit on Intake and the Derived Air Concentration). Finally, the guide defines the operational quantities to be used in estimating the equivalent dose and the effective dose, and also sets out the definitions of some other quantities and concepts to be used in monitoring radiation exposure. The guide does not include the calculation of patient doses carried out for the purposes of quality assurance.

  14. Is There a Dose-Response Relationship for Heart Disease With Low-Dose Radiation Therapy?

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eugene [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Corbett, James R. [Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Moran, Jean M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Griffith, Kent A. [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Marsh, Robin B.; Feng, Mary; Jagsi, Reshma; Kessler, Marc L. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Ficaro, Edward C. [Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Pierce, Lori J., E-mail: ljpierce@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2013-03-15

    Purpose: To quantify cardiac radiation therapy (RT) exposure using sensitive measures of cardiac dysfunction; and to correlate dysfunction with heart doses, in the setting of adjuvant RT for left-sided breast cancer. Methods and Materials: On a randomized trial, 32 women with node-positive left-sided breast cancer underwent pre-RT stress single photon emission computed tomography (SPECT-CT) myocardial perfusion scans. Patients received RT to the breast/chest wall and regional lymph nodes to doses of 50 to 52.2 Gy. Repeat SPECT-CT scans were performed 1 year after RT. Perfusion defects (PD), summed stress defects scores (SSS), and ejection fractions (EF) were evaluated. Doses to the heart and coronary arteries were quantified. Results: The mean difference in pre- and post-RT PD was −0.38% ± 3.20% (P=.68), with no clinically significant defects. To assess for subclinical effects, PD were also examined using a 1.5-SD below the normal mean threshold, with a mean difference of 2.53% ± 12.57% (P=.38). The mean differences in SSS and EF before and after RT were 0.78% ± 2.50% (P=.08) and 1.75% ± 7.29% (P=.39), respectively. The average heart Dmean and D95 were 2.82 Gy (range, 1.11-6.06 Gy) and 0.90 Gy (range, 0.13-2.17 Gy), respectively. The average Dmean and D95 to the left anterior descending artery were 7.22 Gy (range, 2.58-18.05 Gy) and 3.22 Gy (range, 1.23-6.86 Gy), respectively. No correlations were found between cardiac doses and changes in PD, SSS, and EF. Conclusions: Using sensitive measures of cardiac function, no clinically significant defects were found after RT, with the average heart Dmean <5 Gy. Although a dose response may exist for measures of cardiac dysfunction at higher doses, no correlation was found in the present study for low doses delivered to cardiac structures and perfusion, SSS, or EF.

  15. Optimizing Radiation Doses for Computed Tomography Across Institutions: Dose Auditing and Best Practices.

    Science.gov (United States)

    Demb, Joshua; Chu, Philip; Nelson, Thomas; Hall, David; Seibert, Anthony; Lamba, Ramit; Boone, John; Krishnam, Mayil; Cagnon, Christopher; Bostani, Maryam; Gould, Robert; Miglioretti, Diana; Smith-Bindman, Rebecca

    2017-06-01

    Radiation doses for computed tomography (CT) vary substantially across institutions. To assess the impact of institutional-level audit and collaborative efforts to share best practices on CT radiation doses across 5 University of California (UC) medical centers. In this before/after interventional study, we prospectively collected radiation dose metrics on all diagnostic CT examinations performed between October 1, 2013, and December 31, 2014, at 5 medical centers. Using data from January to March (baseline), we created audit reports detailing the distribution of radiation dose metrics for chest, abdomen, and head CT scans. In April, we shared reports with the medical centers and invited radiology professionals from the centers to a 1.5-day in-person meeting to review reports and share best practices. We calculated changes in mean effective dose 12 weeks before and after the audits and meeting, excluding a 12-week implementation period when medical centers could make changes. We compared proportions of examinations exceeding previously published benchmarks at baseline and following the audit and meeting, and calculated changes in proportion of examinations exceeding benchmarks. Of 158 274 diagnostic CT scans performed in the study period, 29 594 CT scans were performed in the 3 months before and 32 839 CT scans were performed 12 to 24 weeks after the audit and meeting. Reductions in mean effective dose were considerable for chest and abdomen. Mean effective dose for chest CT decreased from 13.2 to 10.7 mSv (18.9% reduction; 95% CI, 18.0%-19.8%). Reductions at individual medical centers ranged from 3.8% to 23.5%. The mean effective dose for abdominal CT decreased from 20.0 to 15.0 mSv (25.0% reduction; 95% CI, 24.3%-25.8%). Reductions at individual medical centers ranged from 10.8% to 34.7%. The number of CT scans that had an effective dose measurement that exceeded benchmarks was reduced considerably by 48% and 54% for chest and abdomen, respectively. After

  16. Radiation therapy of intracranial germinomas: optimum radiation dose and treatment volume

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Sei Kyung [Eulji Medical College, Taejon (Korea, Republic of); Suh, Chang Ok; Kim, Gwi Eon [College of Medicine, Yonsei Univ., Seoul (Korea, Republic of)

    1999-09-01

    To evaluate the possibility of decreasing the radiation dose and to determine optimum treatment volume in intracranial germinomas. Forty five patients with pathologically-verified or presumed germinomas by a radiosensitivity test who had been treated with radiotherapy (RT) alone between 1971 and 1992 were retrospectively analyzed. The average age was 17.2 years with 68.9% of the patients being between the ages of 10-20. The male and female ratio was 2.2:1. The locations of the primary tumors were at the pineal regions in 14 patients; the suprasellar regions in 12 patients; and multiple sites in 12 patients. Treatment volumes varied from a small local field (1Q) to the whole brain (7) or entire neuroaxis irradiation(28). All the cases after 1982 received craniospinal irradiation (CSI). Radiation .doses were 41-59 Gv (median 48.5 Gy) to the primary tumor site and 19.5-36 Gy (median 24 Gy) to the neuroaxis. The median follow-up period was 82 months with a range of 2-260 months. All the patients showed complete response after AT. Four patients suffered from recurrence 14. 65. 76, and 170 months after AT,. respectively, and two patients died with intercurrent disease. One of four recurrent cases was salvaged by re-irradiation. Therefore, a 5 and 10 year overall survival was 95.3 % and 84.7 % respectively. Five and ten year disease free survival was 97.6 % and 88.8 % respectively. All the recurrences occurred in the patients who received local RT (3/10) or whole brain RT (1/7) with a radiation dose of 48-50 Gy. None of the patients who received CSJ suffered recurrence. There was no recurrence among the 15 patients who received 45 Gy to the primary site and the 18 patients who received 24 Gy (6 patients received 19.5 Gy) to the neuroaxis. CSI is recommended for the treatment of intracranial germinomas. The radiation dose can be safely decreased to {<=}45 Gy on a primary tumor site and 19.5 Gy on the spine.

  17. Cancer risk from low doses of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Auvinen, A.

    1997-06-01

    The aim of the study was to estimate cancer risk from small doses of ionizing radiation from various sources, including both external and internal exposure. The types of radiation included alpha, gamma, and neutron radiation. A nationwide follow-up study covering the years up to 1992 revealed no significant association between fallout from the Chernobyl accident and incidence of childhood leukemia. An excess of eight cases or more per year could be excluded. However, some indication of an increase was evident in the most heavily affected areas. Furthermore, the risk estimates were in accordance with those reported from Hiroshima and Nagasaki, although the confidence intervals were wide. (282 refs.).

  18. Evaluation of {gamma}-radiation on green tea odor volatiles

    Energy Technology Data Exchange (ETDEWEB)

    Fanaro, G.B., E-mail: gbfanaro@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN)-Centro de Tecnologia das Radiacoes, Av. Professor Lineu Prestes, 2242, 05508-000 Sao Paulo, SP (Brazil); Duarte, R.C., E-mail: renatocduarte@yahoo.com.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN)-Centro de Tecnologia das Radiacoes, Av. Professor Lineu Prestes, 2242, 05508-000 Sao Paulo, SP (Brazil); Araujo, M.M., E-mail: mmozeika@yahoo.co [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN)-Centro de Tecnologia das Radiacoes, Av. Professor Lineu Prestes, 2242, 05508-000 Sao Paulo, SP (Brazil); Purgatto, E., E-mail: epurgatt@usp.b [Universidade de Sao Paulo-Faculdade de Ciencias Farmaceuticas, FCF/USP, Departamento de Alimentos e Nutricao Experimental, Av. Prof. Lineu Prestes, 580 Bloco 14, 05508-900, Sao Paulo, SP (Brazil); Villavicencio, A.L.C.H., E-mail: villavic@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN)-Centro de Tecnologia das Radiacoes, Av. Professor Lineu Prestes, 2242, 05508-000 Sao Paulo, SP (Brazil)

    2011-01-15

    The aim of this study was to evaluate the gamma radiation effects on green tea odor volatiles in green tea at doses of 0, 5, 10, 15 and 20 kGy. The volatile organic compounds were extracted by hydrodistillation and analyzed by GC/MS. The green tea had a large influence on radiation effects, increasing the identified volatiles in relation to control samples. The dose of 10 kGy was responsible to form the majority of new odor compounds following by 5 and 20 kGy. However, the dose of 5 kGy was the dose that degraded the majority of volatiles in non-irradiated samples, following by 20 kGy. The dose of 15 kGy showed has no effect on odor volatiles. The gamma radiation, at dose up to 20 kGy, showed statistically no difference between irradiated and non irradiated green tea on odors compounds.

  19. Radiation Dose-Response Model for Locally Advanced Rectal Cancer After Preoperative Chemoradiation Therapy

    DEFF Research Database (Denmark)

    Appelt, A. L.; Ploen, J.; Vogelius, I. R.

    2013-01-01

    Purpose: Preoperative chemoradiation therapy (CRT) is part of the standard treatment of locally advanced rectal cancers. Tumor regression at the time of operation is desirable, but not much is known about the relationship between radiation dose and tumor regression. In the present study we...... estimated radiation dose-response curves for various grades of tumor regression after preoperative CRT. Methods and Materials: A total of 222 patients, treated with consistent chemotherapy and radiation therapy techniques, were considered for the analysis. Radiation therapy consisted of a combination...... of external-beam radiation therapy and brachytherapy. Response at the time of operation was evaluated from the histopathologic specimen and graded on a 5-point scale (TRG1-5). The probability of achieving complete, major, and partial response was analyzed by ordinal logistic regression, and the effect...

  20. NAIRAS aircraft radiation model development, dose climatology, and initial validation.

    Science.gov (United States)

    Mertens, Christopher J; Meier, Matthias M; Brown, Steven; Norman, Ryan B; Xu, Xiaojing

    2013-10-01

    [1] The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a real-time, global, physics-based model used to assess radiation exposure to commercial aircrews and passengers. The model is a free-running physics-based model in the sense that there are no adjustment factors applied to nudge the model into agreement with measurements. The model predicts dosimetric quantities in the atmosphere from both galactic cosmic rays (GCR) and solar energetic particles, including the response of the geomagnetic field to interplanetary dynamical processes and its subsequent influence on atmospheric dose. The focus of this paper is on atmospheric GCR exposure during geomagnetically quiet conditions, with three main objectives. First, provide detailed descriptions of the NAIRAS GCR transport and dosimetry methodologies. Second, present a climatology of effective dose and ambient dose equivalent rates at typical commercial airline altitudes representative of solar cycle maximum and solar cycle minimum conditions and spanning the full range of geomagnetic cutoff rigidities. Third, conduct an initial validation of the NAIRAS model by comparing predictions of ambient dose equivalent rates with tabulated reference measurement data and recent aircraft radiation measurements taken in 2008 during the minimum between solar cycle 23 and solar cycle 24. By applying the criterion of the International Commission on Radiation Units and Measurements (ICRU) on acceptable levels of aircraft radiation dose uncertainty for ambient dose equivalent greater than or equal to an annual dose of 1 mSv, the NAIRAS model is within 25% of the measured data, which fall within the ICRU acceptable uncertainty limit of 30%. The NAIRAS model predictions of ambient dose equivalent rate are generally within 50% of the measured data for any single-point comparison. The largest differences occur at low latitudes and high cutoffs, where the radiation dose level is low. Nevertheless, analysis

  1. CT radiation dose and image quality optimization using a porcine model.

    Science.gov (United States)

    Zarb, Francis; McEntee, Mark F; Rainford, Louise

    2013-01-01

    To evaluate potential radiation dose savings and resultant image quality effects with regard to optimization of commonly performed computed tomography (CT) studies derived from imaging a porcine (pig) model. Imaging protocols for 4 clinical CT suites were developed based on the lowest milliamperage and kilovoltage, the highest pitch that could be set from current imaging protocol parameters, or both. This occurred before significant changes in noise, contrast, and spatial resolution were measured objectively on images produced from a quality assurance CT phantom. The current and derived phantom protocols were then applied to scan a porcine model for head, abdomen, and chest CT studies. Further optimized protocols were developed based on the same methodology as in the phantom study. The optimization achieved with respect to radiation dose and image quality was evaluated following data collection of radiation dose recordings and image quality review. Relative visual grading analysis of image quality criteria adapted from the European guidelines on radiology quality criteria for CT were used for studies completed with both the phantom-based or porcine-derived imaging protocols. In 5 out of 16 experimental combinations, the current clinical protocol was maintained. In 2 instances, the phantom protocol reduced radiation dose by 19% to 38%. In the remaining 9 instances, the optimization based on the porcine model further reduced radiation dose by 17% to 38%. The porcine model closely reflects anatomical structures in humans, allowing the grading of anatomical criteria as part of image quality review without radiation risks to human subjects. This study demonstrates that using a porcine model to evaluate CT optimization resulted in more radiation dose reduction than when imaging protocols were tested solely on quality assurance phantoms.

  2. Radiation Doses and Associated Risk From the Fukushima Nuclear Accident.

    Science.gov (United States)

    Ishikawa, Tetsuo

    2017-03-01

    The magnitude of dose due to the Fukushima Daiichi Accident was estimated by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2013 report published in April 2014. Following this, the UNSCEAR white paper, which comprises a digest of new information for the 2013 Fukushima report, was published in October 2015. Another comprehensive report on radiation dose due to the accident is the International Atomic Energy Agency (IAEA) report on the Fukushima Daiichi Accident published in August 2015. Although the UNSCEAR and IAEA publications well summarize doses received by residents, they review only literature published before the end of December 2014 and the end of March 2015, respectively. However, some studies on dose estimation have been published since then. In addition, the UNSCEAR 2013 report states it was likely that some overestimation had been introduced generally by the methodology used by the Committee. For example, effects of decontamination were not considered in the lifetime external dose estimated. Decontamination is in progress for most living areas in Fukushima Prefecture, which could reduce long-term external dose to residents. This article mainly reviews recent English language articles that may add new information to the UNSCEAR and IAEA publications. Generally, recent articles suggest lower doses than those presented by the UNSCEAR 2013 report.

  3. Chronic low-dose radiation protects cells from high-dose radiation via increase of AKT expression by NF-{sub k}B

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyung Sun; Seong, Ki Moon; Kim, Ji Young; Kim, Cha Soon; Yang, Kwang Hee; Nam, Seon Young [Radiation Effect Research Team, Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., LTD., Gyeongju (Korea, Republic of)

    2013-04-15

    Exposure to low-dose and low-dose rate of ionizing radiation is an important issue in radiation protection. Low-dose ionizing radiation has been observed to elicit distinctly different responses compared to high-dose radiation, in various biological systems including the reproductive, immune, and hematopoietic systems (Liu et al. 2006). Some data were reported that low-dose radiation could initiate beneficial effects by stimulating cell growth, DNA repair, activation of transcription factors and gene expression (Calabrese et al., 2004). Cells exposed to low-dose radiation can develop adaptive resistance to subsequent high-dose radiation induced DNA damage, gene mutation, and cell death. We previously reported that low-dose of ionizing radiation induced cell survival through the activation of AKT (protein kinase B, PKB) pathway (Park et al., 2009). AKT has been shown to be potently activated in response to a wide variety of growth factors and ionizing radiation. Cell survival against ionizing radiation seems to be associated with the activation of AKT pathway via phosphorylation of its downstream nuclear target molecules. In the present study, we examined the effects of chronic low-dose irradiation in human lung fibroblast cells. The aim was to explore the possibility of a low-dose radiation-induced adaptive cellular response against subsequent challenging high-dose irradiation. In the present study, we examined the regulatory mechanism responsible for cellular response induced by chronic low-dose of ionizing radiation in normal human cells. We found that the level of AKT protein was closely associated with cell survival. In addition, NF-{sub k}B activation by chronic low-dose radiation regulates AKT activation via gene expression and acinus expression. In conclusion, our data demonstrate that chronic low-dose radiation could inhibit the cell death induced by cytotoxic high-dose radiation through the modulation of the level of AKT and acinus proteins via NF-{sub k

  4. Absorbed radiation doses to staff after implementation of a radiopharmacy clean room.

    Science.gov (United States)

    Ponto, James A

    2014-12-01

    In response to U.S. Pharmacopeia general chapter standards, a clean room was constructed for our in-house radiopharmacy. Previously, most patient doses were prepared as needed just before injection. Currently, to minimize repeated entries into the clean room, most patient doses are prepared in batches; that is, early morning and noontime preparation of doses to be injected at various times throughout the morning and the afternoon, respectively. Because these patient doses may be prepared well before injection time, radioactive decay necessitates higher amounts of radioactivity to be handled for patient dose preparation. Hence, absorbed radiation doses to staff, all of whom rotate into the radiopharmacy clean room in addition to their regular patient-related activities, were retrospectively evaluated. Monthly dosimetry reports for body (chest badge) and extremities (finger ring) were retrospectively reviewed for each staff member for 12 mo before and 12 mo after implementation of the radiopharmacy clean room. Monthly data were evaluated for average and SD, and 12-mo groups were evaluated using a paired t test. Data for the second 12-mo period were also normalized to the same number of patient doses to account for an increase in procedure volume and were reevaluated. Before the radiopharmacy clean room had been implemented, average monthly absorbed radiation doses to body and extremities were 23 ± 15 mrem (0.23 ± 0.15 mSv) and 93 ± 59 mrem (0.93 ± 0.59 mSv), respectively. After the clean room had been implemented, average monthly absorbed radiation doses increased to 32 ± 16 mrem (0.32 ± 0.16 mSv) (P radiopharmacy clean room, absorbed radiation doses to body and extremities increased by 26% and 18%, respectively, even after normalizing for procedure volume. Because absorbed radiation doses from other activities, such as patient dose administration and patient imaging, are assumed to remain relatively constant, these increases in absorbed radiation doses to

  5. Radiation dose reduction in parasinus CT by spectral shaping.

    Science.gov (United States)

    May, Matthias S; Brand, Michael; Lell, Michael M; Sedlmair, Martin; Allmendinger, Thomas; Uder, Michael; Wuest, Wolfgang

    2017-02-01

    Spectral shaping aims to narrow the X-ray spectrum of clinical CT. The aim of this study was to determine the image quality and the extent of radiation dose reduction that can be achieved by tin prefiltration for parasinus CT. All scans were performed with a third generation dual-source CT scanner. A study protocol was designed using 100 kV tube voltage with tin prefiltration (200 mAs) that provides image noise levels comparable to a low-dose reference protocol using 100 kV without spectral shaping (25 mAs). One hundred consecutive patients were prospectively enrolled and randomly assigned to the study or control group. All patients signed written informed consent. The study protocol was approved by the local Institutional Review Board and applies to the HIPAA. Subjective and objective image quality (attenuation values, image noise, and contrast-to-noise ratio (CNR)) were assessed. Radiation exposure was assessed as volumetric CT dose index, and effective dose was estimated. Mann-Whitney U test was performed for radiation exposure and for image noise comparison. All scans were of diagnostic image quality. Image noise in air, in the retrobulbar fat, and in the eye globe was comparable between both groups (all p > 0.05). CNReye globe/air did not differ significantly between both groups (p = 0.7). Radiation exposure (1.7 vs. 2.1 mGy, p image quality.

  6. Integrated Worker Radiation Dose Assessment for the K Basins

    Energy Technology Data Exchange (ETDEWEB)

    NELSON, J.V.

    1999-10-27

    This report documents an assessment of the radiation dose workers at the K Basins are expected to receive in the process of removing spent nuclear fuel from the storage basins. The K Basins (K East and K West) are located in the Hanford 100K Area.

  7. Radiation doses to normal tissues during craniospinal irradiation ...

    African Journals Online (AJOL)

    Mohamed Farouk Mostafa

    2011-10-15

    Oct 15, 2011 ... From the above mentioned study we can conclude that, the dose of radiation received by the target volume and the organs at risk during craniospinal irradiation of children with high risk medulloblastoma with the use of our new linear accelera- tor and treatment planning system Elekta and Precise Elekta is.

  8. Image quality and radiation dose in cardiac imaging

    NARCIS (Netherlands)

    van Dijk, Joris David

    2016-01-01

    Coronary artery disease is a major cause of death accounting for 8% of all deaths in the Netherlands. This disease can be detected in an early stage by cardiac imaging. However, this detection comes at the price of a relatively high radiation dose which is potentially harmful for the patient.

  9. Can radiation therapy treatment planning system accurately predict surface doses in postmastectomy radiation therapy patients?

    Science.gov (United States)

    Wong, Sharon; Back, Michael; Tan, Poh Wee; Lee, Khai Mun; Baggarley, Shaun; Lu, Jaide Jay

    2012-01-01

    Skin doses have been an important factor in the dose prescription for breast radiotherapy. Recent advances in radiotherapy treatment techniques, such as intensity-modulated radiation therapy (IMRT) and new treatment schemes such as hypofractionated breast therapy have made the precise determination of the surface dose necessary. Detailed information of the dose at various depths of the skin is also critical in designing new treatment strategies. The purpose of this work was to assess the accuracy of surface dose calculation by a clinically used treatment planning system and those measured by thermoluminescence dosimeters (TLDs) in a customized chest wall phantom. This study involved the construction of a chest wall phantom for skin dose assessment. Seven TLDs were distributed throughout each right chest wall phantom to give adequate representation of measured radiation doses. Point doses from the CMS Xio® treatment planning system (TPS) were calculated for each relevant TLD positions and results correlated. There were no significant difference between measured absorbed dose by TLD and calculated doses by the TPS (p > 0.05 (1-tailed). Dose accuracy of up to 2.21% was found. The deviations from the calculated absorbed doses were overall larger (3.4%) when wedges and bolus were used. 3D radiotherapy TPS is a useful and accurate tool to assess the accuracy of surface dose. Our studies have shown that radiation treatment accuracy expressed as a comparison between calculated doses (by TPS) and measured doses (by TLD dosimetry) can be accurately predicted for tangential treatment of the chest wall after mastectomy. Copyright © 2012 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  10. Methionine Uptake and Required Radiation Dose to Control Glioblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Iuchi, Toshihiko, E-mail: tiuchi@chiba-cc.jp [Division of Neurological Surgery, Chiba Cancer Center, Chiba (Japan); Hatano, Kazuo [Division of Radiation Oncology, Tokyo Bay Advanced Imaging and Radiation Oncology Clinic, Makuhari, Chiba (Japan); Uchino, Yoshio [Division of Nuclear Medicine, Chiba Ryogo Center, Chiba (Japan); Itami, Makiko [Division of Surgical Pathology, Chiba Cancer Center, Chiba (Japan); Hasegawa, Yuzo; Kawasaki, Koichiro; Sakaida, Tsukasa [Division of Neurological Surgery, Chiba Cancer Center, Chiba (Japan); Hara, Ryusuke [Division of Radiation Oncology, Chiba Cancer Center, Chiba (Japan)

    2015-09-01

    Purpose: The purpose of this study was to retrospectively assess the feasibility of radiation therapy planning for glioblastoma multiforme (GBM) based on the use of methionine (MET) positron emission tomography (PET), and the correlation among MET uptake, radiation dose, and tumor control. Methods and Materials: Twenty-two patients with GBM who underwent MET-PET prior to radiation therapy were enrolled. MET uptake in 30 regions of interest (ROIs) from 22 GBMs, biologically effective doses (BEDs) for the ROIs and their ratios (MET uptake:BED) were compared in terms of whether the ROIs were controlled for >12 months. Results: MET uptake was significantly correlated with tumor control (odds ratio [OR], 10.0; P=.005); however, there was a higher level of correlation between MET uptake:BED ratio and tumor control (OR, 40.0; P<.0001). These data indicated that the required BEDs for controlling the ROIs could be predicted in terms of MET uptake; BED could be calculated as [34.0 × MET uptake] Gy from the optimal threshold of the MET uptake:BED ratio for tumor control. Conclusions: Target delineation based on MET-PET was demonstrated to be feasible for radiation therapy treatment planning. MET-PET could not only provide precise visualization of infiltrating tumor cells but also predict the required radiation doses to control target regions.

  11. Differentially Expressed Genes Associated with Low-Dose Gamma Radiation

    Science.gov (United States)

    Hegyesi, Hargita; Sándor, Nikolett; Schilling, Boglárka; Kis, Enikő; Lumniczky, Katalin; Sáfrány, Géza

    We have studied low dose radiation induced gene expression alterations in a primary human fibroblast cell line using Agilent's whole human genome microarray. Cells were irradiated with 60Co γ-rays (0; 0.1; 0.5 Gy) and 2 hours later total cellular RNA was isolated. We observed differential regulation of approximately 300-500 genes represented on the microarray. Of these, 126 were differentially expressed at both doses, among them significant elevation of GDF-15 and KITLG was confirmed by qRT-PCR. Based on the transcriptional studies we selected GDF-15 to assess its role in radiation response, since GDF-15 is one of the p53 gene targets and is believed to participate in mediating p53 activities. First we confirmed gamma-radiation induced dose-dependent changes in GDF-15 expression by qRT-PCR. Next we determined the effect of GDF-15 silencing on radiosensitivity. Four GDF-15 targeting shRNA expressing lentiviral vectors were transfected into immortalized human fibroblast cells. We obtained efficient GDF-15 silencing in one of the four constructs. RNA interference inhibited GDF-15 gene expression and enhanced the radiosensitivity of the cells. Our studies proved that GDF-15 plays an essential role in radiation response and may serve as a promising target in radiation therapy.

  12. The effects of x-ray beam hardening on detective quantum efficiency and radiation dose.

    Science.gov (United States)

    Wong, Molly Donovan; Wu, Xizeng; Liu, Hong

    2011-01-01

    The goal of this preliminary study was to investigate the effects of x-ray beam hardening on the detective quantum efficiency (DQE) and the radiation dose of an inline x-ray imaging system. The ability to decrease the risk of harmful radiation to the patient without compromising the detection capability would more effectively balance the tradeoff between image quality and radiation dose, and therefore benefit the fields of diagnostic x-ray imaging, especially mammography. The DQE and the average glandular dose were both calculated under the same experimental conditions for a range of beam hardening levels, corresponding to no added beam hardening and two thicknesses each of Rhodium (Rh) and Molybdenum (Mo) filters. The dose calculation results demonstrate a reduction of 15% to 24% for the range of beam hardening levels. The comparison of all quantities comprising the DQE exhibit very close correlation between the results obtained without added beam hardening to the results corresponding to the range of beam hardening levels. For the specific experimental conditions utilized in this preliminary study, the results are an indication that the use of beam hardening holds the potential to reduce the radiation dose without decreasing the performance of the system. Future studies will seek to apply this method in a clinical environment and perform a comprehensive image quality evaluation, in an effort to further evaluate the potential of beam hardening to balance the tradeoff between dose and image quality.

  13. On the radiation dose required to cure intracranial germinoma

    Energy Technology Data Exchange (ETDEWEB)

    Shibamoto, Yuta [Kyoto Univ. (Japan). Inst. for Frontier Medical Sciences

    1999-09-01

    Despite its high radiosensitivity, intracranial germinoma has most often been treated with a radiation dose of 50 Gy. Relatively old literature suggested that 50 Gy was appropriate, but several newer studies indicate that 40-45 Gy may be sufficient. Regarding this issue, we conducted a phase II study in which the total dose to the primary site was planned to be 40 Gy to tumors <2.5 cm in diameter, 45 Gy to 2.5-4 cm tumors, and 50 Gy to tumors >4 cm, using 1.6-1.8 Gy daily fractions. Thirty-eight patients were enrolled. Within a median follow-up period of 116 months, no patients developed local recurrence, and only two developed CSF dissemination. Intracranial germinoma <4 cm in diameter can be cured with radiation doses of 40-45 Gy. Radiotherapy alone with these reduced doses should be compared with the ongoing protocols of chemotherapy plus further reduced dose (24-30 Gy) radiation in future studies. (author)

  14. Effect of low-dose radiation on ocular circulation

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Keiko; Hiroishi, Goro; Honda, Masae; Yoshikawa, Hiroshi; Fujisawa, Kimihiko; Ishibashi, Tatsuro [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1999-05-01

    We treated 6 eyes of unilateral age-related macular degeneration by low-dose radiation. Each eye received daily dose of 2 Gy by 4MV lineac totalling 20 Gy over 2 weeks. Color doppler flowmetry was used to determine the mean blood flow velocity (Vmean) and vascular resistive index (RI) in the short posterior ciliary artery, central retinal artery and ophthalmic artery in the treated and fellow eyes before and up to 6 months of treatment. There were no significant differences in Vmean and RI before and after treatment. The findings show the absence of apparent influence of low-dose radiation on the ocular circulation in age-related macular degeneration. (author)

  15. Completeness of reporting of radiation therapy planning, dose, and delivery in veterinary radiation oncology manuscripts from 2005 to 2010.

    Science.gov (United States)

    Keyerleber, Michele A; McEntee, Margaret C; Farrelly, John; Podgorsak, Matthew

    2012-01-01

    Surrounding a shift toward evidence-based medicine and widespread adoption of reporting guidelines such as the Consolidated Standards of Reporting Trials (CONSORT) statement, there has been a growing body of literature evaluating the quality of reporting in human and veterinary medicine. These reviews have consistently demonstrated the presence of substantive deficiencies in completeness of reporting. The purpose of this study was to assess the current status of reporting in veterinary radiation oncology manuscripts in regards to treatment planning methods, dose, and delivery and to introduce a set of reporting guidelines to serve as a standard for future reporting. Forty-six veterinary radiation oncology manuscripts published between 2005 and 2010 were evaluated for reporting of 50 items pertaining to patient data, treatment planning, radiation dose, delivery of therapy, quality assurance, and adjunctive therapy. A mean of 40% of checklist items were reported in a given manuscript (range = 8-75%). Only 9/50 (18%) checklist items were reported in > or = 80% manuscripts. The completeness of reporting was best in regards to a statement of prescription radiation protocol (91-98% reported) and worst in regards to specification of absorbed dose within target volumes and surrounding normal tissues (0-6% reported). No manuscripts met the current International Commission of Radiation Units and Measurements (ICRU) dose specification recommendations. Incomplete reporting may stem from the predominance of retrospective manuscripts and the variability of protocols and equipment in veterinary radiation oncology. Adoption of reporting guidelines as outlined in this study is recommended to improve the quality of reporting in veterinary radiation oncology.

  16. Retrospective Evaluation Reveals That Long-term Androgen Deprivation Therapy Improves Cause-Specific and Overall Survival in the Setting of Dose-Escalated Radiation for High-Risk Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Felix Y., E-mail: ffeng@med.umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Radiation Oncology, Veterans Affairs Medical Center, Ann Arbor, Michigan (United States); Blas, Kevin; Olson, Karin; Stenmark, Matthew [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Sandler, Howard [Cedars Sinai Medical Center, Los Angeles, California (United States); Hamstra, Daniel A. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2013-05-01

    Purpose: To evaluate the role of androgen deprivation therapy (ADT) and duration for high-risk prostate cancer patients treated with dose-escalated radiation therapy (RT). Methods and Materials: A retrospective analysis of high-risk prostate cancer patients treated with dose-escalated RT (minimum 75 Gy) with or without ADT was performed. The relationship between ADT use and duration with biochemical failure (BF), metastatic failure (MF), prostate cancer-specific mortality (PCSM), non-prostate cancer death (NPCD), and overall survival (OS) was assessed as a function of pretreatment characteristics, comorbid medical illness, and treatment using Fine and Gray's cumulative incidence methodology. Results: The median follow-up time was 64 months. In men with National Comprehensive Cancer Network defined high-risk prostate cancer treated with dose-escalated RT, on univariate analysis, both metastasis (P<.0001; hazard ratio 0.34; 95% confidence interval 0.18-0.67; cumulative incidence at 60 months 13% vs 35%) and PCSM (P=.015; hazard ratio 0.41; 95% confidence interval 0.2-1.0; cumulative incidence at 60 months 6% vs 11%) were improved with the use of ADT. On multivariate analysis for all high-risk patients, Gleason score was the strongest negative prognostic factor, and long-term ADT (LTAD) improved MF (P=.002), PCSM (P=.034), and OS (P=.001). In men with prostate cancer and Gleason scores 8 to 10, on multivariate analysis after adjustment for other risk features, there was a duration-dependent improvement in BF, metastasis, PCSM, and OS, all favoring LTAD in comparison with STAD or RT alone. Conclusion: For men with high-risk prostate cancer treated with dose-escalated EBRT, this retrospective study suggests that the combination of LTAD and RT provided a significant improvement in clinical outcome, which was especially true for those with Gleason scores of 8 to 10.

  17. Analysis of Radiation Doses and Dose Reduction Strategies During Cerebral Digital Subtraction Angiography.

    Science.gov (United States)

    Yi, Ho Jun; Sung, Jae Hoon; Lee, Dong Hoon; Kim, Sang Wook; Lee, Sang Won

    2017-04-01

    Adverse effects of increased use of cerebral digital subtraction angiography (DSA) include radiation-induced skin reactions and increased risk of malignancy. This study aimed to identify a method for reducing radiation exposure during routine cerebral DSA. A retrospective review of 138 consecutive adult patients who underwent DSA with a biplane angiography system (Artis Zee, Siemens, Germany) from September 2015 to February 2016 was performed. In January 2016, the dose parameter was reset by the manufacturer from 2.4 μGy to 1.2 μGy. Predose (group 1) and postdose parameter reduction (group 2) groups were established. Angiograms and procedure examination protocols were reviewed according to patient age, gender, and diagnosis and angiography techniques were reviewed on the basis of the following radiation dose parameters: fluoroscopy time, reference point air kerma (Ka,r; in mGy), and kerma-area product (PKA; in μGym2). The mean Ka,r values in groups 1 and 2 were 1841.5 mGy and 1274.8 mGy, respectively. The mean PKA values in groups 1 and 2 were 23212.5 μGym2 and 14854.0 μGym2, respectively. Ka,r and PKA values were significantly lower in group 2 compared with group 1 (P strategies to reduce radiation dose, led to lower radiation doses for DSA. The use of appropriate examinations and low-dose parameters in fluoroscopy contributed significantly to the radiation dose reductions. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. First trial of spatial and temporal fractionations of the delivered dose using synchrotron microbeam radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Serduc, Raphael [Toulouse Univ. (France). UPS Centre de Recherche Cerveau et Cognition; CNRS, CerCo, Toulouse (France); European Synchrotron Radiation Facility, 38 - Grenoble (France); Braeuer-Krisch, Elke; Bouchet, Audrey; Brochard, Thierry; Bravin, Alberto; Le Duc, Geraldine [European Synchrotron Radiation Facility, 38 - Grenoble (France); Renaud, Luc [Toulouse Univ. (France). UPS Centre de Recherche Cerveau et Cognition; CNRS, CerCo, Toulouse (France); Laissue, Jean Albert [Bern Univ. (Switzerland). Inst. of Pathology

    2009-07-15

    The technical feasibility of temporal and spatial fractionations of the radiation dose has been evaluated using synchrotron microbeam radiation therapy for brain tumors in rats. A significant increase in lifespan (216%, p<0.0001) resulted when three fractions of microbeam irradiation were applied to the tumor through three different ports, orthogonal to each other, at 24 h intervals. However, there were no long-term survivors, and immunohistological studies revealed that 9 L tumors were not entirely ablated. (orig.)

  19. Level of radiation dose in university hospital non-insured private health screening programs in Korea

    Directory of Open Access Journals (Sweden)

    Yun-Keun Lee

    2016-03-01

    Full Text Available Objectives The aim of this study is to evaluate radiation exposure resulting from the comprehensive health examinations of selected university hospital programs and to present basic data for research and management strategies on the health effects of medical radiation exposure. Methods Radiation-based diagnostic studies of the comprehensive health examination programs of ten university hospitals in Seoul, Korea, as introduced in their websites, were analyzed. The medical radiation studies of the programs were reviewed by radiologists. Only the effective doses of the basic studies were included in the analysis. The optional studies of the programs were excluded. Results Among the 190 comprehensive health examination programs, 132 programs (69.5% included computed tomography studies, with an average of 1.4 scans. The average effective dose of radiation by program was 3.62 mSv for an intensive program for specific diseases; 11.12 mSv for an intensive program for cancer; 18.14 mSv for a premium program; and 24.08 mSv for an overnight program. A higher cost of a programs was linked to a higher effective dose (r=0.812. The effective doses of the examination programs for the same purposes differed by as much as 2.1 times by hospital. Inclusion of positron emission tomography–computed tomography was the most critical factor in determining the level of effective dose. Conclusions It was found that radiation exposure dose from comprehensive health exam programs targeted for an asymptomatic, healthy public reached between 3.6 and 24 times the annual dose limit for the general public. Relevant management policies at the national level should be provided to minimize medical radiation exposure.

  20. Limiting CT radiation dose in children with craniosynostosis: phantom study using model-based iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kaasalainen, Touko; Lampinen, Anniina [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 340, Helsinki (Finland); University of Helsinki, Department of Physics, Helsinki (Finland); Palmu, Kirsi [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 340, Helsinki (Finland); School of Science, Aalto University, Department of Biomedical Engineering and Computational Science, Helsinki (Finland); Reijonen, Vappu; Kortesniemi, Mika [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 340, Helsinki (Finland); Leikola, Junnu [University of Helsinki and Helsinki University Hospital, Department of Plastic Surgery, Helsinki (Finland); Kivisaari, Riku [University of Helsinki and Helsinki University Hospital, Department of Neurosurgery, Helsinki (Finland)

    2015-09-15

    Medical professionals need to exercise particular caution when developing CT scanning protocols for children who require multiple CT studies, such as those with craniosynostosis. To evaluate the utility of ultra-low-dose CT protocols with model-based iterative reconstruction techniques for craniosynostosis imaging. We scanned two pediatric anthropomorphic phantoms with a 64-slice CT scanner using different low-dose protocols for craniosynostosis. We measured organ doses in the head region with metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters. Numerical simulations served to estimate organ and effective doses. We objectively and subjectively evaluated the quality of images produced by adaptive statistical iterative reconstruction (ASiR) 30%, ASiR 50% and Veo (all by GE Healthcare, Waukesha, WI). Image noise and contrast were determined for different tissues. Mean organ dose with the newborn phantom was decreased up to 83% compared to the routine protocol when using ultra-low-dose scanning settings. Similarly, for the 5-year phantom the greatest radiation dose reduction was 88%. The numerical simulations supported the findings with MOSFET measurements. The image quality remained adequate with Veo reconstruction, even at the lowest dose level. Craniosynostosis CT with model-based iterative reconstruction could be performed with a 20-μSv effective dose, corresponding to the radiation exposure of plain skull radiography, without compromising required image quality. (orig.)

  1. Effects of low dose gamma radiation on the early growth of red pepper and the resistance to subsquent high dose of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. S.; Baek, M. H.; Kim, D. H.; Lee, Y. K. [KAERI, Taejon (Korea, Republic of); Lee, Y. B. [Chungnam National Univ., Taejon (Korea, Republic of)

    2001-05-01

    Red pepper (capsicum annuum L. cv. Jokwang and cv. Johong) seeds were irradiated with the dose of 0{approx}50 Gy to investigated the effect of the low dose gamma radiation on the early growth and resistance to subsequent high dose of radiation. The effect of the low dose gamma radiation on the early growth and resistance to subsequenct high dose of radiation were enhanced in Johong cultivar but not in Jokwang cultivar. Germination rate and early growth of Johong cultivar were noticeably increased at 4 Gy-, 8 Gy- and 20 Gy irradiation group. Resistance to subsequent high dose of radiation of Johong cultivar were increased at almost all of the low dose irradiation group. Especially it was highest at 4 Gy irradiation group. The carotenoid contents and enzyme activity on the resistance to subsequent high dose of radiation of Johong cultivar were increased at the 4 Gy and 8 Gy irradiation group.

  2. Cellular response to low dose radiation: Role of phosphatidylinositol-3 kinase like kinases

    Energy Technology Data Exchange (ETDEWEB)

    Balajee, A.S.; Meador, J.A.; Su, Y.

    2011-03-24

    It is increasingly realized that human exposure either to an acute low dose or multiple chronic low doses of low LET radiation has the potential to cause different types of cancer. Therefore, the central theme of research for DOE and NASA is focused on understanding the molecular mechanisms and pathways responsible for the cellular response to low dose radiation which would not only improve the accuracy of estimating health risks but also help in the development of predictive assays for low dose radiation risks associated with tissue degeneration and cancer. The working hypothesis for this proposal is that the cellular mechanisms in terms of DNA damage signaling, repair and cell cycle checkpoint regulation are different for low and high doses of low LET radiation and that the mode of action of phosphatidylinositol-3 kinase like kinases (PIKK: ATM, ATR and DNA-PK) determines the dose dependent cellular responses. The hypothesis will be tested at two levels: (I) Evaluation of the role of ATM, ATR and DNA-PK in cellular response to low and high doses of low LET radiation in simple in vitro human cell systems and (II) Determination of radiation responses in complex cell microenvironments such as human EpiDerm tissue constructs. Cellular responses to low and high doses of low LET radiation will be assessed from the view points of DNA damage signaling, DNA double strand break repair and cell cycle checkpoint regulation by analyzing the activities (i.e. post-translational modifications and kinetics of protein-protein interactions) of the key target proteins for PI-3 kinase like kinases both at the intra-cellular and molecular levels. The proteins chosen for this proposal are placed under three categories: (I) sensors/initiators include ATM ser1981, ATR, 53BP1, gamma-H2AX, MDC1, MRE11, Rad50 and Nbs1; (II) signal transducers include Chk1, Chk2, FANCD2 and SMC1; and (III) effectors include p53, CDC25A and CDC25C. The primary goal of this proposal is to elucidate the

  3. Design study on dose evaluation method for employees at severe accident

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Yoshitaka; Irie, Takashi; Kohriyama, Tamio [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan); Kudo, Seiichi [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Nishimura, Kazuya [Computer Software Development Corp. Ltd., Tokyo (Japan)

    2002-06-01

    If a severe accident occurs in a pressurized water reactor plant, it is required to estimate dose values of operators engaged in emergency such as accident management, repair of failed parts. However, it might be difficult to measure radiation dose rate during the progress of an accident, because radiation monitors are not always installed in areas where the emergency activities are required. In this study, we analyzed the transport of radioactive materials in case of a severe accident, investigated a method to obtain radiation dose rate in the plant from estimated radioactive sources, made up a prototype analyzing system from this design study, and then evaluated its availability. As a result, we obtained the following: (1) A new dose evaluation method was established to predict the radiation dose rate at any point in the plant during a severe accident scenario. (2) This evaluation of total dose including access route and time for emergency activities is useful for estimating radiation dose limit for these employee actions. (3) The radiation dose rate map is effective for identifying high radiation areas and for choosing a route with lower radiation dose rate. (author)

  4. Calcium antagonists protect mice against lethal doses of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Floersheim, G.L. (University Hospitals, Basel (Switzerland). Dept. of Research)

    1992-11-01

    Currently available radioprotectors are poorly tolerated in man and the general use of aminothiol radioprotectors is compromised by side-effects. In a search for less toxic radioprotective agents, diltiazem, a calcium antagonist with a benzothiazepine structure, was found to protect mice against a lethal (LD[sub 100]) [gamma] radiation dose allowing survival of up to 93%. Dihydropyridine calcium antagonists such as nifedipine, nimodipine, isradipine and nitrendipine also provided radioprotection. Calcium antagonists might attenuate radiation-induced injury by inhibiting cellular calcium overload, subsequent to cell membrane damage caused by radiation-generated free radicals. In view of their good tolerance, calcium antagonists may be applied safely in situations of radiation exposure, including radiotherapy and internal radionuclide contamination. These calcium antagonists may also be viewed in other contexts where free radicals are implicated in pathological processes. (Author).

  5. Evaluation of the absorbed dose in odontological computerized tomography; Avaliacao da dose absorvida em tomografia computadorizada odontologica

    Energy Technology Data Exchange (ETDEWEB)

    Legnani, Adriano; Schelin, Hugo R.; Rocha, Anna Silvia P.S. da, E-mail: schelin@utfpr.edu.b, E-mail: anna@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Khoury, Helen J., E-mail: khoury@ufpe.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2011-10-26

    This paper evaluated the absorbed dose at the surface entry known as 'cone beam computed tomography' (CBCT) in odontological computerized tomography. Examination were simulated with CBCT for measurements of dose. A phantom were filled with water, becoming scatter object of radiation. Thermoluminescent dosemeters were positioned on points correspondent to eyes and salivary glands

  6. Single-portal-phase low-tube-voltage dual-energy CT for short-term follow-up of acute pancreatitis: evaluation of CT severity index, interobserver agreement and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Wichmann, Julian L. [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Universitaetsklinikum Frankfurt, Institut fuer Diagnostische und Interventionelle Radiologie, Frankfurt am Main (Germany); Majenka, Pawel; Beeres, Martin; Kromen, Wolfgang; Schulz, Boris; Bauer, Ralf W.; Kerl, J.M.; Gruber-Rouh, Tatjana; Hammerstingl, Renate; Vogl, Thomas J.; Lehnert, Thomas [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Wesarg, Stefan [Fraunhofer IGD, Cognitive Computing and Medical Imaging, Darmstadt (Germany)

    2014-11-15

    To intra-individually compare single-portal-phase low-tube-voltage (100-kVp) computed tomography (CT) with 120-kVp images for short-term follow-up assessment of CT severity index (CTSI) of acute pancreatitis, interobserver agreement and radiation dose. We retrospectively analysed 66 patients with acute pancreatitis who underwent initial dual-contrast-phase CT (unenhanced, arterial, portal phase) at admission and short-term (mean interval 11.4 days) follow-up dual-contrast-phase dual-energy CT. The 100-kVp and linearly blended images representing 120-kVp acquisition follow-up CT images were independently evaluated by three radiologists using a modified CTSI assessing pancreatic inflammation, necrosis and extrapancreatic complications. Scores were compared with paired t test and interobserver agreement was evaluated using intraclass correlation coefficients (ICC). Mean CTSI scores on unenhanced, portal- and dual-contrast-phase images were 4.9, 6.1 and 6.2 (120 kVp) and 5.0, 6.0 and 6.1 (100 kVp), respectively. Contrast-enhanced series showed a higher CTSI compared to unenhanced images (P < 0.05) but no significant differences between single- and dual-contrast-phase series (P > 0.7). CTSI scores were comparable for 100-kVp and 120-kVp images (P > 0.05). Interobserver agreement was substantial for all evaluated series and subcategories (ICC 0.67-0.93). DLP of single-portal-phase 100-kVp images was reduced by 41 % compared to 120-kVp images (363.8 versus 615.9 mGy cm). Low-tube-voltage single-phase 100-kVp CT provides sufficient information for follow-up evaluation of acute pancreatitis and significantly reduces radiation exposure. (orig.)

  7. Scientific Risk Estimation on Health Effects of Low Dose and Low Dose-Rate Radiation - An Overview

    Directory of Open Access Journals (Sweden)

    Tetsuya Ono

    2009-06-01

    Full Text Available Estimation of the scientific risks of high dose radiation has been successfully quantified by many studies using several different approaches. However, the risk for low and low dose-rate radiation is obscure because of a lack of evidence. This risk is currently estimated by extrapolating the radiation response at high doses into low dose ranges for practical purposes. Recent challenges to examine directly the biological responses to low dose radiation using newly developed technologies are unveiling interesting alterations at the molecular level. The interpretation of these data, however, needs careful consideration because they may not be related to any change in biological functions.

  8. Galactic cosmic ray-induced radiation dose on terrestrial exoplanets.

    Science.gov (United States)

    Atri, Dimitra; Hariharan, B; Grießmeier, Jean-Mathias

    2013-10-01

    This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground- and space-based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets that reside in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Planetary systems around M dwarfs are considered to be prime candidates to search for life beyond the Solar System. Such planets are likely to be tidally locked and have close-in habitable zones. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in the case of super-Earths. Such exoplanets are subjected to a high flux of galactic cosmic rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin that strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another factor governing the radiation dose is the depth of the planetary atmosphere. The higher the depth of the planetary atmosphere, the lower the flux of secondary particles will be on the surface. If the secondary particles are energetic enough, and their flux is sufficiently high, the radiation from muons can also impact the subsurface regions, such as in the case of Mars. If the radiation dose is too high, the chances of sustaining a long-term biosphere on the planet are very low. We have examined the dependence of the GCR-induced radiation dose on the strength of the planetary magnetic field and its atmospheric depth, and found that the latter is the decisive factor for the protection of a planetary biosphere.

  9. Gamma knife radiosurgery for vestibular schwannomas: results of hearing preservation in relation to the cochlear radiation dose.

    NARCIS (Netherlands)

    Timmer, F.C.A.; Hanssens, P.E.; Haren, A.E. van; Mulder, J.J.S.; Cremers, C.W.R.J.; Beynon, A.J.; Overbeeke, J.J. van; Graamans, K.

    2009-01-01

    OBJECTIVES/HYPOTHESIS: This study was designed to evaluate hearing preservation after gamma knife radiosurgery (GKRS) and to determine the relation between hearing preservation and cochlear radiation dose in patients with a sporadic vestibular schwannoma (VS). METHODS: Prospective study involving

  10. Radiation dose metrics in CT: assessing dose using the National Quality Forum CT patient safety measure.

    Science.gov (United States)

    Keegan, Jillian; Miglioretti, Diana L; Gould, Robert; Donnelly, Lane F; Wilson, Nicole D; Smith-Bindman, Rebecca

    2014-03-01

    The National Quality Forum (NQF) is a nonprofit consensus organization that recently endorsed a measure focused on CT radiation doses. To comply, facilities must summarize the doses from consecutive scans within age and anatomic area strata and report the data in the medical record. Our purpose was to assess the time needed to assemble the data and to demonstrate how review of such data permits a facility to understand doses. To assemble the data we used for analysis, we used the dose monitoring software eXposure to automatically export dose metrics from consecutive scans in 2010 and 2012. For a subset of 50 exams, we also collected dose metrics manually, copying data directly from the PACS into an excel spreadsheet. Manual data collection for 50 scans required 2 hours and 15 minutes. eXposure compiled the data in under an hour. All dose metrics demonstrated a 30% to 50% reduction between 2010 and 2012. There was also a significant decline and a reduction in the variability of the doses over time. The NQF measure facilitates an institution's capacity to assess the doses they are using for CT as part of routine practice. The necessary data can be collected within a reasonable amount of time either with automatic software or manually. The collection and review of these data will allow facilities to compare their radiation dose distributions with national distributions and allow assessment of temporal trends in the doses they are using. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  11. Radiation dose and radiation risk to foetuses and newborns during X-ray examinations

    Energy Technology Data Exchange (ETDEWEB)

    Kettunen, A. [Oulu Univ. (Finland)

    2004-05-01

    The purpose of this study is to determine the way in which the demands set by degree 423/2000 by the Ministry of Social Affairs and Health are fulfilled with respect to the most radiosensitive groups, the foetus and the child, by estimating the radiation dose and radiation risk to the foetus from x-ray examinations of an expectant mother's pelvic region, finding out the practice involved in preventing doses to embryos and foetuses and assessing dose practices in cases where an embryo or foetus is or shall be exposed, and by estimating radiation dose and risk due to the radiation received by a new-born being treated in a paediatric intensive care unit. No statistics are available in Finland to indicate how many x-ray examinations of the pelvic region and lower abdomen are made to pregnant patients or to show the dose and risk to the foetus due these examinations. In order to find out the practices in radiological departments concerning the pelvic x-ray examination of fertile woman and the number of foetuses exposed, a questionnaire was sent to all radiation safety officers responsible for the safe use of radiation (n = 290). A total of 173 questionnaires were returned. This study recorded the technique and Dose-Area Product of 118 chest examinations of newborns in paediatric intensive care units. Entrance surface doses and effective doses were calculated separately to each newborn. Based on the patient records, the number of all x-ray examinations during the study was calculated and the effective doses were estimated retrospectively to each child. The radiation risk was estimated both for the foetuses and for the newborns. According to this study, it is rare in Finland to expose a pregnant woman to radiation. On the other hand, with the exception of pelvimetry examinations, there are no compiled statistics concerning the number of pelvic x-ray examinations of a pregnant woman. There was no common practice on how to exclude the possibility of pregnancy. The dose

  12. Low-dose ionizing radiation alleviates Aβ42-induced defective phenotypes in Drosophila Alzheimer's disease models

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, SooJin; Jeong, Hae Min; Nam, Seon Young [Low-dose Radiation Research Team, Radiation Health Institute, Korea Hydro & Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

    2017-04-15

    Alzheimer's disease (AD) is the most common neurodegenerative disease that is characterized by amyloid plaques, progressive neuronal loss, and gradual deterioration of memory. Amyloid imaging using positron emission tomography (PET) radiotracers have been developed and approved for clinical use in the evaluation of suspected neurodegenerative disease, including AD. Particularly, previous studies involving low-dose ionizing radiation on Aβ 42-treated mouse hippocampal neurons have suggested a potential role for low-dose ionizing radiation in the treatment of AD. However, associated in vivo studies involving the therapy effects of low-dose ionizing radiation on AD are still insufficient. As a powerful cell biological system, Drosophila AD models have been generated and established a useful model organism for study on the etiology of human AD. In this study, we investigated the hormesis effects of low-dose ionizing radiation on Drosophila AD models. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation.

  13. ROLES OF RADIATION DOSE AND CHEMOTHERAPY IN THE ETIOLOGY OF STOMACH CANCER AS A SECOND MALIGNANCY

    NARCIS (Netherlands)

    van den Belt-Dusebout, Alexandra W.; Aleman, Berthe M. P.; Besseling, Gijs; de Bruin, Marie L.; Hauptmann, Michael; van 't Veer, Mars B.; de Wit, Ronald; Ribot, Jacques G.; Noordijk, Evert M.; Kerst, J. Martijn; Gietema, Jourik A.; van Leeuwen, Flora E.

    2009-01-01

    Purpose: To evaluate the roles of radiation dose, chemotherapy, and other factors in the etiology of stomach cancer in long-term survivors of testicular cancer or Hodgkin lymphoma. Methods and Materials: We conducted a cohort study in 5,142 survivors of testicular cancer or Hodgkin lymphoma treated

  14. The leaded apron revisited: does it reduce gonadal radiation dose in dental radiology

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R.E.; Harris, A.M.; van der Merwe, E.J.; Nortje, C.J. (Ontario Cancer Institute, Princess Margaret Hospital, Toronto (Canada))

    1991-05-01

    A tissue-equivalent anthropomorphic human phantom was used with a lithium fluoride thermoluminescent dosimetry system to evaluate the radiation absorbed dose to the ovarian and testicular region during dental radiologic procedures. Measurements were made with and without personal lead shielding devices consisting of thyroid collar and apron of 0.25 mm lead thickness equivalence. The radiation absorbed dose with or without lead shielding did not differ significantly from control dosimeters in vertex occlusal and periapical views (p greater than 0.05). Personal lead shielding devices did reduce gonadal dose in the case of accidental exposure (p less than 0.05). A leaded apron of 0.25 mm lead thickness equivalent was permeable to radiation in direct exposure testing.

  15. The leaded apron revisited: does it reduce gonadal radiation dose in dental radiology?

    Science.gov (United States)

    Wood, R E; Harris, A M; van der Merwe, E J; Nortjé, C J

    1991-05-01

    A tissue-equivalent anthropomorphic human phantom was used with a lithium fluoride thermoluminescent dosimetry system to evaluate the radiation absorbed dose to the ovarian and testicular region during dental radiologic procedures. Measurements were made with and without personal lead shielding devices consisting of thyroid collar and apron of 0.25 mm lead thickness equivalence. The radiation absorbed dose with or without lead shielding did not differ significantly from control dosimeters in vertex occlusal and periapical views (p greater than 0.05). Personal lead shielding devices did reduce gonadal dose in the case of accidental exposure (p less than 0.05). A leaded apron of 0.25 mm lead thickness equivalent was permeable to radiation in direct exposure testing.

  16. Evaluation of dose reduction and image quality in CT colonography: Comparison of low-dose CT with iterative reconstruction and routine-dose CT with filtered back projection

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Koichi [Kameda Medical Center, Department of Radiology, Kamogawa, Chiba (Japan); Jichi Medical University, Department of Radiology, Tochigi (Japan); National Cancer Center, Cancer Screening Technology Division, Research Center for Cancer Prevention and Screening, Tokyo (Japan); Fujiwara, Masanori; Mogi, Tomohiro; Iida, Nao [Kameda Medical Center Makuhari, Department of Radiology, Chiba (Japan); Kanazawa, Hidenori; Sugimoto, Hideharu [Jichi Medical University, Department of Radiology, Tochigi (Japan); Mitsushima, Toru [Kameda Medical Center Makuhari, Department of Gastroenterology, Chiba (Japan); Lefor, Alan T. [Jichi Medical University, Department of Surgery, Tochigi (Japan)

    2015-01-15

    To prospectively evaluate the radiation dose and image quality comparing low-dose CT colonography (CTC) reconstructed using different levels of iterative reconstruction techniques with routine-dose CTC reconstructed with filtered back projection. Following institutional ethics clearance and informed consent procedures, 210 patients underwent screening CTC using automatic tube current modulation for dual positions. Examinations were performed in the supine position with a routine-dose protocol and in the prone position, randomly applying four different low-dose protocols. Supine images were reconstructed with filtered back projection and prone images with iterative reconstruction. Two blinded observers assessed the image quality of endoluminal images. Image noise was quantitatively assessed by region-of-interest measurements. The mean effective dose in the supine series was 1.88 mSv using routine-dose CTC, compared to 0.92, 0.69, 0.57, and 0.46 mSv at four different low doses in the prone series (p < 0.01). Overall image quality and noise of low-dose CTC with iterative reconstruction were significantly improved compared to routine-dose CTC using filtered back projection. The lowest dose group had image quality comparable to routine-dose images. Low-dose CTC with iterative reconstruction reduces the radiation dose by 48.5 to 75.1 % without image quality degradation compared to routine-dose CTC with filtered back projection. (orig.)

  17. Intussusception reduction: Effect of air vs. liquid enema on radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Summer L.; Edgar, J.C.; Anupindi, Sudha A.; Zhu, Xiaowei [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA (United States); Magill, Dennise; Felice, Marc A. [University of Pennsylvania, Environmental Health and Radiation Safety, Philadelphia, PA (United States)

    2017-10-15

    Both air and radiopaque liquid contrast are used to reduce ileocolic intussusception under fluoroscopy. Some suggest air lowers radiation dose due to shorter procedure times. However, air enema likely lowers radiation dose regardless of fluoroscopy time due to less density over the automatic exposure control cells. We test the hypothesis that air enema reduction of ileocolic intussusception results in lower radiation dose than liquid contrast enema independent of fluoroscopy time. We describe a role for automatic exposure control in this dose difference. We retrospectively evaluated air and liquid intussusception reductions performed on a single digital fluoroscopic unit during a 26-month period. We compared patient age, weight, gender, exam time of day and year, performing radiologist(s), radiographic image acquisitions, grid and magnification use, fluoroscopy time and dose area product. We compared categorical and continuous variables statistically using chi-square and Mann-Whitney U tests, respectively. The mean dose area product was 2.7-fold lower for air enema, 1.3 ± 0.9 dGy.cm{sup 2}, than for liquid, 3.5 ± 2.5 dGy.cm{sup 2} (P<0.005). The mean fluoroscopy time was similar between techniques. The mean dose area product/min was 2.3-fold lower for air, 0.6 ± 0.2 dGy.cm{sup 2}/min, than for liquid, 1.4 ± 0.5 dGy.cm{sup 2}/min (P<0.001). No group differences were identified in other measured dose parameters. Fluoroscopic intussusception reduction using air enema uses less than half the radiation dose of liquid contrast enema. Dose savings are independent of fluoroscopy time and are likely due to automatic exposure control interaction. (orig.)

  18. Radiation equivalent dose simulations for long-term interplanetary flights

    Science.gov (United States)

    Dobynde, M. I.; Drozdov, A.; Shprits, Y. Y.

    2016-12-01

    Cosmic particle radiation is a limiting factor for the human interplanetary flights. The unmanned flights inside heliosphere and human flights inside of magnetosphere tend to become a routine procedure, whereas there have been only few shot term human flights out of it (Apollo missions 1969-1972) with maximum duration less than a month. Long-term human flights set much higher requirements to the radiation shielding, primarily because of long exposition to cosmic radiation. Inside the helosphere there are two main sources of cosmic radiation: galactic cosmic rays (GCR) and soalr particle events (SPE). GCR come from the outside of heliosphere forming a background of overall radiation that affects the spacecraft. The intensity of GCR is varied according to solar activity, increasing with solar activity decrease and backward, with the modulation time (time between nearest maxima) of 11 yeas. SPE are shot term events, comparing to GCR modulation time, but particle fluxes are much more higher. The probability of SPE increases with the increase of solar activity. Time dependences of the intensity of these two components encourage looking for a time window of flight, when intensity and effect of GCR and SPE would be minimized. Combining GEANT4 Monte Carlo simulations with time dependent model of GCR spectra and data on SPE spectra we show the time dependence of the radiation dose in an anthropomorphic human phantom inside the shielding capsule. Different types of particles affect differently on the human providing more or less harm to the tissues. We use quality factors to recalculate absorbed dose into biological equivalent dose, which give more information about risks for astronaut's health. Incident particles provide a large amount of secondary particles while propagating through the shielding capsule. We try to find an optimal combination of shielding material and thickness, that will effectively decrease the incident particle energy, at the same time minimizing flow

  19. High-dose radiation sensor with wireless optical detection

    Science.gov (United States)

    Knapkiewicz, Paweł; Augustyniak, Izabela; Sareło, Katarzyna; Gorecka-Drzazga, Anna; Dziuban, Jan

    2017-05-01

    We present a miniature silicon-glass MEMS sensor for measurement of high doses of ionizing radiation (above 10 kGy) using a novel wireless optical detection method. The radiation sensor is a miniaturized version of the so-called hydrogen dosimeter. An amount of high-density polyethylene, located inside the MEMS sensor, degrades under ionizing radiation, releasing gaseous hydrogen. The increasing pressure deflects the thin silicon membrane. The sensor’s destructive and proportional modes of work are also proposed. In the destructive mode, sensors provide in situ information on excessive and discrete levels of radiation. The optical detection method is based on an optical head consisting of a moving membrane and a silicon screen with a matrix of micro-holes. Laser light is reflected from the membrane and scattered when the membrane is deflected, in the process illuminating the holes on the silicon screen. The number of illuminated holes is a function of the degree of membrane deflection; the transformation of the holes to the deflection allows for the calculation of pressure and eventually the dose of ionizing radiation.

  20. Evaluation of low-dose proton beam radiation efficiency in MIA PaCa-2 pancreatic cancer cell line vitality and H2AX formation

    Directory of Open Access Journals (Sweden)

    Aušra Liubavičiūtė

    2015-11-01

    Conclusions: Our data demonstrate that low-doses proton beam irradiation had an effect on MIA PaCa-2 pancreatic carcinoma cell line. Full extent of irradiation had an impact only 24 h postirradiation, triggering DNA arrested cell cycle in G1/0 phase. Formed DNA DSBs were found to be repaired via the NHEJ pathway mechanism within 72 h. Unsuccessful repaired DSBs induced apoptotic cell death. After 72 h reparation processes were completed, and cell cycle was released from arrest in G1/0 phase.

  1. Radiation doses inside industrial irradiation installation with linear electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Alexandre R., E-mail: alexandre.lima@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Pelegrineli, Samuel Q.; Alo, Gabriel F., E-mail: samuelfisica@yahoo.com.br, E-mail: gabriel.alo@aceletron.com.br [Aceletron Irradiacao Industrial, Aceletrica Comercio e Representacoes Ltda, Rio de Janeiro, RJ (Brazil); Silva, Francisco C.A. Da, E-mail: dasilva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Aceletron Industrial Irradiation Company is the unique installation in South America to provide industrial irradiation service using two linear electron accelerators of 18 kW and 10 MeV energy. The electron beam technology allows using electrons to irradiate many goods and materials, such as hospital and medical equipment, cosmetics, herbal products, polymers, peat, gemstones and food. Aceletron Company uses a concrete bunker with 3.66 m of thickness to provide the necessary occupational and environmental radiation protection of X-rays produced. The bunker is divided in main four areas: irradiation room, maze, tower and pit. Inside the irradiation room the x-rays radiation rates are measured in two ways: direct beam and 90 deg C. The rates produced in the conveyor system using 10 MeV energy are 500 Gy/min/mA and 15 Gy/min/mA, respectively. For a 1.8 mA current, the rates produced are 900 Gy/min and 27 Gy/min, respectively. Outside the bunker the radiation rate is at background level, but in the tower door and modulation room the radiation rate is 10 μSv/h. In 2014, during a routine operation, an effective dose of 30.90 mSv was recorded in a monthly individual dosimeter. After the investigation, it was concluded that the dose was only in the dosimeter because it felt inside the irradiation room. As Aceletron Company follows the principles of safety culture, it was decided to perform the radiation isodose curves, inside the four areas of the installation, to know exactly the hotspots positions, exposure times and radiation doses. Five hotspots were chosen taking into account worker's routes and possible operational places. The first experiment was done using a package with three TLD and OSLD dosimeters to obtain better statistical results. The first results for the five hotspots near the accelerator machine showed that the radiation dose rates were between 26 Gy/h and 31 Gy/h. The final measurements were performed using a package with one TLD and one OSLD

  2. Single-portal-phase low-tube-voltage dual-energy CT for short-term follow-up of acute pancreatitis: evaluation of CT severity index, interobserver agreement and radiation dose.

    Science.gov (United States)

    Wichmann, Julian L; Majenka, Pawel; Beeres, Martin; Kromen, Wolfgang; Schulz, Boris; Wesarg, Stefan; Bauer, Ralf W; Kerl, J Matthias; Gruber-Rouh, Tatjana; Hammerstingl, Renate; Vogl, Thomas J; Lehnert, Thomas

    2014-11-01

    To intra-individually compare single-portal-phase low-tube-voltage (100-kVp) computed tomography (CT) with 120-kVp images for short-term follow-up assessment of CT severity index (CTSI) of acute pancreatitis, interobserver agreement and radiation dose. We retrospectively analysed 66 patients with acute pancreatitis who underwent initial dual-contrast-phase CT (unenhanced, arterial, portal phase) at admission and short-term (mean interval 11.4 days) follow-up dual-contrast-phase dual-energy CT. The 100-kVp and linearly blended images representing 120-kVp acquisition follow-up CT images were independently evaluated by three radiologists using a modified CTSI assessing pancreatic inflammation, necrosis and extrapancreatic complications. Scores were compared with paired t test and interobserver agreement was evaluated using intraclass correlation coefficients (ICC). Mean CTSI scores on unenhanced, portal- and dual-contrast-phase images were 4.9, 6.1 and 6.2 (120 kVp) and 5.0, 6.0 and 6.1 (100 kVp), respectively. Contrast-enhanced series showed a higher CTSI compared to unenhanced images (P  0.7). CTSI scores were comparable for 100-kVp and 120-kVp images (P > 0.05). Interobserver agreement was substantial for all evaluated series and subcategories (ICC 0.67-0.93). DLP of single-portal-phase 100-kVp images was reduced by 41 % compared to 120-kVp images (363.8 versus 615.9 mGy cm). Low-tube-voltage single-phase 100-kVp CT provides sufficient information for follow-up evaluation of acute pancreatitis and significantly reduces radiation exposure. • Single-portal-phase CT provides sufficient evaluation for follow-up of acute pancreatitis. • Follow-up CT does not benefit from unenhanced or arterial-phase acquisition. • CT severity index scores are equal for dual-contrast-phase 100-/120-kVp acquisition (P > 0.05). • 100-kVp single-portal-phase follow-up CT of acute pancreatitis significantly reduces radiation exposure.

  3. Radiation doses from Hanford site releases to the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Farris, W.T.; Napier, B.A.; Ikenberry, T.A.

    1994-06-01

    Radiation doses to individuals were estimated for the years 1944-1992. The dose estimates were based on the radioactive-releases from the Hanford Site in south central Washington. Conceptual models and computer codes were used to reconstruct doses through the early 1970s. The published Hanford Site annual environmental data were used to complete the does history through 1992. The most significant exposure pathway was found to be the consumption of cow`s milk containing iodine-131. For the atmospheric pathway, median cumulative dose estimates to the thyroid of children ranged from < 0.1 to 235 rad throughout the area studied. The geographic distribution of the dose levels was directly related to the pattern of iodine-131 deposition and was affected by the distribution of commercial milk and leafy vegetables. For the atmospheric pathway, the-highest estimated cumulative-effective-dose-equivalent (EDE) to an adult was estimated to be 1 rem at Ringold, Washington for the period 1944-1992. For the Columbia River pathway, cumulative EDE estimates ranged from <0.5 to l.5 rem cumulative dose to maximally exposed adults downriver from the Hanford Site for the years 1944-1992. The most significant river exposure pathway was consumption of resident fish containing phosphorus-32 and zinc-65.

  4. 3D deterministic radiation transport for dose computations in clinical procedures

    Science.gov (United States)

    Al-Basheer, Ahmad

    The main goal of this dissertation was to establish the feasibility of basing megavoltage external photon beam absorbed dose calculations in voxelized phantoms on SN deterministic calculations and pre-calculated electron absorbed dose kernels derived from full-physics Monte Carlo. The SN derived electron absorbed dose kernel method EDK-SN, developed as part of this research, achieves total execution times that are on the order of several times to orders of magnitude faster than conventional full-physics Monte Carlo electron transport methods considering equivalently detailed models and data fidelity. With the rapid movement toward intensity modulated radiation therapy (IMRT), radiation beam intensities have increased dramatically over the past decade, thus heightening the need for further characterization of out-of-field organ absorbed doses, along with their associated biological risks. Assessment of these tissue absorbed doses is complicated by two fundamental limitations. First, anatomic information on the patient is generally restricted to a partial body CT image acquired for treatment planning; consequently, whole-body computational phantoms must be employed to provide the out-of-field anatomy model structure for absorbed dose evaluation. Second, existing methods based on Monte Carlo radiation transport, even with the application significant variance reduction, are quite computationally inefficient at large distances from the primary beam, and point-kernel methods do not properly handle tissue inhomogeneities. Moreover, since absorbed dose are generally tracked in all major organs in the body, variance reduction schemes for Monte Carlo are not all effective in this regard. The outcome of this dissertation is to demonstrate that absorbed dose from high-energy external beams radiation can be accurately computed for whole body and organ-specific absorbed doses. The EDK-SN method implements voxelized phantoms with discrete ordinates (SN) transport computations

  5. Radiation doses to children during modified barium swallow studies

    Energy Technology Data Exchange (ETDEWEB)

    Weir, Kelly A. [University of Queensland, Discipline of Paediatrics and Child Health, School of Medicine, Herston, Queensland (Australia); McMahon, Sandra M. [SpeechNet Speech Pathology Services, Brisbane (Australia); Long, Gillian; Bunch, Judith A. [Royal Children' s Hospital, Department of Medical Imaging, Herston (Australia); Pandeya, Nirmala [Queensland Institute of Medical Research, Herston (Australia); Coakley, Kerry S. [Biomedical Technology Services, Royal Brisbane and Women' s Hospital, Herston (Australia); Chang, Anne B. [Royal Children' s Hospital, Department of Respiratory Medicine, Herston (Australia)

    2007-03-15

    There are minimal data on radiation doses to infants and children undergoing a modified barium swallow (MBS) study. To document screening times, dose area product (DAP) and effective doses to children undergoing MBS and to determine factors associated with increased screening times and effective dose. Fluoroscopic data (screening time, DAP, kVp) for 90 consecutive MBS studies using pulse fluoroscopy were prospectively recorded; effective dose was calculated and data were analyzed for effects of behavior, number of swallow presentations, swallowing dysfunction and medical problems. Mean effective dose for the entire group was 0.0826 {+-} 0.0544 mSv, screening time 2.48 {+-} 0.81 min, and DAP 28.79 {+-} 41.72 cGy cm{sup 2}. Significant differences were found across three age groups ({<=}1.0, >1.0-3.0 and >3.0 years) for effective dose (mean 0.1188, 0.0651 and 0.0529 mSv, respectively; P < 0.001), but not for screening time or DAP. Effective dose was correlated with screening time (P = 0.007), DAP (P < 0.001), number of swallow presentations (P = 0.007), lower age (P = 0.017), female gender (P = 0.004), and height (P < 0.001). Screening time was correlated with total number of swallow presentations (P < 0.001) and DAP (P < 0.001). Screening times, DAP, effective dose, and child and procedural factors associated with higher effective doses are presented for children undergoing MBS studies. (orig.)

  6. Digital radiography of scoliosis with a scanning method: radiation dose optimization

    Energy Technology Data Exchange (ETDEWEB)

    Geijer, Haakan; Andersson, Torbjoern [Department of Radiology, Oerebro University Hospital, 701 85 Oerebro (Sweden); Verdonck, Bert [Philips Medical Systems, P.O. Box 10,000, 5680 Best (Netherlands); Beckman, Karl-Wilhelm; Persliden, Jan [Department of Medical Physics, Oerebro University Hospital, 701 85 Oerebro (Sweden)

    2003-03-01

    The aim of this study was optimization of the radiation dose-image quality relationship for a digital scanning method of scoliosis radiography. The examination is performed as a digital multi-image translation scan that is reconstructed to a single image in a workstation. Entrance dose was recorded with thermoluminescent dosimeters placed dorsally on an Alderson phantom. At the same time, kerma area product (KAP) values were recorded. A Monte Carlo calculation of effective dose was also made. Image quality was evaluated with a contrast-detail phantom and Visual Grading. The radiation dose was reduced by lowering the image intensifier entrance dose request, adjusting pulse frequency and scan speed, and by raising tube voltage. The calculated effective dose was reduced from 0.15 to 0.05 mSv with reduction of KAP from 1.07 to 0.25 Gy cm{sup 2} and entrance dose from 0.90 to 0.21 mGy. The image quality was reduced with the Image Quality Figure going from 52 to 62 and a corresponding reduction in image quality as assessed with Visual Grading. The optimization resulted in a dose reduction to 31% of the original effective dose with an acceptable reduction in image quality considering the intended use of the images for angle measurements. (orig.)

  7. Radiation Dose Reduction in Computed Tomography-Guided Lung Interventions using an Iterative Reconstruction Technique.

    Science.gov (United States)

    Chang, D H; Hiss, S; Mueller, D; Hellmich, M; Borggrefe, J; Bunck, A C; Maintz, D; Hackenbroch, M

    2015-10-01

    To compare the radiation doses and image qualities of computed tomography (CT)-guided interventions using a standard-dose CT (SDCT) protocol with filtered back projection and a low-dose CT (LDCT) protocol with both filtered back projection and iterative reconstruction. Image quality and radiation doses (dose-length product and CT dose index) were retrospectively reviewed for 130 patients who underwent CT-guided lung interventions. SDCT at 120 kVp and automatic mA modulation and LDCT at 100 kVp and a fixed exposure were each performed for 65 patients. Image quality was objectively evaluated as the contrast-to-noise ratio and subjectively by two radiologists for noise impression, sharpness, artifacts and diagnostic acceptability on a four-point scale. The groups did not significantly differ in terms of diagnostic acceptability and complication rate. LDCT yielded a median 68.6% reduction in the radiation dose relative to SDCT. In the LDCT group, iterative reconstruction was superior to filtered back projection in terms of noise reduction and subjective image quality. The groups did not differ in terms of beam hardening artifacts. LDCT was feasible for all procedures and yielded a more than two-thirds reduction in radiation exposure while maintaining overall diagnostic acceptability, safety and precision. The iterative reconstruction algorithm is preferable according to the objective and subjective image quality analyses. Implementation of a low-dose computed tomography (LDCT) protocol for lung interventions is feasible and safe. LDCT protocols yield a significant reduction (more than 2/3) in radiation exposure. Iterative reconstruction algorithms considerably improve the image quality in LDCT protocols. © Georg Thieme Verlag KG Stuttgart · New York.

  8. Evaluation of dose reduction and image quality in CT colonography: comparison of low-dose CT with iterative reconstruction and routine-dose CT with filtered back projection.

    Science.gov (United States)

    Nagata, Koichi; Fujiwara, Masanori; Kanazawa, Hidenori; Mogi, Tomohiro; Iida, Nao; Mitsushima, Toru; Lefor, Alan T; Sugimoto, Hideharu

    2015-01-01

    To prospectively evaluate the radiation dose and image quality comparing low-dose CT colonography (CTC) reconstructed using different levels of iterative reconstruction techniques with routine-dose CTC reconstructed with filtered back projection. Following institutional ethics clearance and informed consent procedures, 210 patients underwent screening CTC using automatic tube current modulation for dual positions. Examinations were performed in the supine position with a routine-dose protocol and in the prone position, randomly applying four different low-dose protocols. Supine images were reconstructed with filtered back projection and prone images with iterative reconstruction. Two blinded observers assessed the image quality of endoluminal images. Image noise was quantitatively assessed by region-of-interest measurements. The mean effective dose in the supine series was 1.88 mSv using routine-dose CTC, compared to 0.92, 0.69, 0.57, and 0.46 mSv at four different low doses in the prone series (p iterative reconstruction were significantly improved compared to routine-dose CTC using filtered back projection. The lowest dose group had image quality comparable to routine-dose images. Low-dose CTC with iterative reconstruction reduces the radiation dose by 48.5 to 75.1% without image quality degradation compared to routine-dose CTC with filtered back projection. • Low-dose CTC reduces radiation dose ≥ 48.5% compared to routine-dose CTC. • Iterative reconstruction improves overall CTC image quality compared with FBP. • Iterative reconstruction reduces overall CTC image noise compared with FBP. • Automated exposure control with iterative reconstruction is useful for low-dose CTC.

  9. Megagray Dosimetry (or Monitoring of Very Large Radiation Doses)

    DEFF Research Database (Denmark)

    McLaughlin, W.L.; Uribe, R.M.; Miller, Arne

    1983-01-01

    A number of suitably calibrated plastic and dyed films and solid-state systems can provide mapping of very intense radiation fields with high spatial resolution and reasonable limits of uncertainty of absorbed dose assessment. Although most systems of this type suffer from rate dependence and tem.......g., polyhalostyrenes), some dyed cellulosics, radiochromic dye films (e.g., Nylonbase “Trogamid” films) and pure LiF crystals....

  10. Non linear processes modulated by low doses of radiation exposure

    Science.gov (United States)

    Mariotti, Luca; Ottolenghi, Andrea; Alloni, Daniele; Babini, Gabriele; Morini, Jacopo; Baiocco, Giorgio

    The perturbation induced by radiation impinging on biological targets can stimulate the activation of several different pathways, spanning from the DNA damage processing to intra/extra -cellular signalling. In the mechanistic investigation of radiobiological damage this complex “system” response (e.g. omics, signalling networks, micro-environmental modifications, etc.) has to be taken into account, shifting from a focus on the DNA molecule solely to a systemic/collective view. An additional complication comes from the finding that the individual response of each of the involved processes is often not linear as a function of the dose. In this context, a systems biology approach to investigate the effects of low dose irradiations on intra/extra-cellular signalling will be presented, where low doses of radiation act as a mild perturbation of a robustly interconnected network. Results obtained through a multi-level investigation of both DNA damage repair processes (e.g. gamma-H2AX response) and of the activation kinetics for intra/extra cellular signalling pathways (e.g. NFkB activation) show that the overall cell response is dominated by non-linear processes - such as negative feedbacks - leading to possible non equilibrium steady states and to a poor signal-to-noise ratio. Together with experimental data of radiation perturbed pathways, different modelling approaches will be also discussed.

  11. Low dose radiation damage effects in silicon strip detectors

    Science.gov (United States)

    Wiącek, P.; Dąbrowski, W.

    2016-11-01

    The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

  12. The consequence of day-to-day stochastic dose deviation from the planned dose in fractionated radiation therapy.

    Science.gov (United States)

    Paul, Subhadip; Roy, Prasun Kumar

    2016-02-01

    Radiation therapy is one of the important treatment procedures of cancer. The day-to-day delivered dose to the tissue in radiation therapy often deviates from the planned fixed dose per fraction. This day-to-day variation of radiation dose is stochastic. Here, we have developed the mathematical formulation to represent the day-to-day stochastic dose variation effect in radiation therapy. Our analysis shows that that the fixed dose delivery approximation under-estimates the biological effective dose, even if the average delivered dose per fraction is equal to the planned dose per fraction. The magnitude of the under-estimation effect relies upon the day-to-day stochastic dose variation level, the dose fraction size and the values of the radiobiological parameters of the tissue. We have further explored the application of our mathematical formulation for adaptive dose calculation. Our analysis implies that, compared to the premise of the Linear Quadratic Linear (LQL) framework, the Linear Quadratic framework based analytical formulation under-estimates the required dose per fraction necessary to produce the same biological effective dose as originally planned. Our study provides analytical formulation to calculate iso-effect in adaptive radiation therapy considering day-to-day stochastic dose deviation from planned dose and also indicates the potential utility of LQL framework in this context.

  13. Evaluation of skin entrance radiation dose in pediatric patients undergoing chest X-rays exams; Avaliacao da dose de entrada na pele em pacientes pediatricos submetidos a exames radiograficos do torax

    Energy Technology Data Exchange (ETDEWEB)

    Gabardo, Farly Piantini

    2016-07-01

    The aim of this work was to estimate the incident air kerma of lateral (LAT) and anterior-posterior (AP) together with posterior-anterior (PA) projection chest X-ray exams in one of the largest pediatric hospitals in Brazil. Dosimetric results are accompanied with the detailed analysis of patient characteristics and radiographer strategy. The exams of 225 (119 male and 106 female) patients were studied and 389 X-ray exams (200 AP/PA projections and 189 LAT projections) of pediatric patients were acquired. Patient thickness can be restored from age, height or weight with the uncertainty of ∼20-30%. Very slight correlation between the patient dose and thickness was observed with the difference in dose for patients of the same thickness reaching 4 times. By standardization of radiological protocols, it should be possible to keep dose within the intervals 50-100 μGy for LAT projection and 40-80 μGy for AP/PA projection. The dose values are lower than those recommended by major European guidelines to good practice. (author)

  14. Radiation dose and subsequent risk for stomach cancer in long-term survivors of cervical cancer

    DEFF Research Database (Denmark)

    Kleinerman, Ruth A; Smith, Susan A; Holowaty, Eric

    2013-01-01

    To assess the dose-response relationship for stomach cancer after radiation therapy for cervical cancer.......To assess the dose-response relationship for stomach cancer after radiation therapy for cervical cancer....

  15. The EOS imaging system: Workflow and radiation dose in scoliosis examinations

    DEFF Research Database (Denmark)

    Mussmann, Bo; Torfing, Trine; Jespersen, Stig

    Introduction The EOS imaging system is a biplane slot beam scanner capable of full body scans at low radiation dose and without geometrical distortion. It was implemented in our department primo 2012 and all scoliosis examinations are now performed in EOS. The system offers improved possibility...... The purpose of the study was to evaluate workflow defined as scheduled time pr. examination and radiation dose in scoliosis examinations in EOS compared to conventional x-ray evaluation. Materials and Methods: The Dose Area Product (DAP) was measured with a dosimeter and a comparison between conventional X......-ray and EOS was made. The Workflow in 2011 was compared to the workflow in 2013 with regards to the total number of examinations and the scheduled examination time for scoliosis examinations. Results: DAP for a scoliosis examination in conventional X-ray was 185 mGy*cm2 and 60.36 mGy*cm2 for EOS...

  16. Low doses effects and gamma radiations low dose rates; Les effets des faibles doses et des faibles debits de doses de rayons gamma

    Energy Technology Data Exchange (ETDEWEB)

    Averbeck, D. [Institut Curie, CNRS UMR 2027, 75 - Paris (France)

    1999-07-01

    This expose wishes for bringing some definitions and base facts relative to the problematics of low doses effects and low dose rates effects. It shows some already used methods and some actual experimental approaches by focusing on the effects of ionizing radiations with a low linear energy transfer. (N.C.)

  17. Evaluation of radiation protection conditions in intraoral radiology

    Energy Technology Data Exchange (ETDEWEB)

    Miguel, Cristiano; Barros, Frieda Saicla; Rocha, Anna Silvia Penteado Setti da, E-mail: miguel_cristianoch@yahoo.com.br [Universidade Tecnologica Federal do Parana (PPGEB/UTFPR), Curitiba, PR (Brazil). Programa de Pos-graduacao em Engenharia Biomedica; Tilly Junior, Joao Gilberto [Universidade Federal do Parana (UNIR/UFPR), Curitiba, PR (Brazil). Hospital de Clinicas. Unidade de Imagem e Radioterapia; Almeida, Claudio Domingues de [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Dept. de Fisica Medica

    2016-04-15

    Introduction: The dental radiology represents about 20% of human exposure to radiation in radio diagnostic. Although the doses practiced in intraoral dentistry are considered low, they should not be ignored due to the volume of the performed procedures. This study presents the radiation protection conditions for intraoral radiology in Curitiba - PR. Methods: Data was collected through a quantitative field research of a descriptive nature during the period between September of 2013 and December of 2014. The survey sample consisted of 97 dentists and 130 intraoral equipment. The data related to the equipment was collected using structured questions and quality control evaluations. The evaluations of the entrance skin dose, the size of the radiation field and the total filtration were performed with dosimetry kits provided and evaluated by IRD/CNEN. The exposure time and voltage were measured using noninvasive detectors. The occupational dose was verified by thermoluminescent dosimeters. The existence of personal protection equipment, the type of image processing and knowledge of dentists about radiation protection were verified through the application of a questionnaire. Results: Among the survey's results, it is important to emphasize that 90% of the evaluated equipment do not meet all the requirements of the Brazilian radiation protection standards. Conclusion: The lack of knowledge about radiation protection, the poor operating conditions of the equipment, and the image processing through visual method are mainly responsible for the unnecessary exposure of patients to ionizing radiation. (author)

  18. Mechanisms underlying cellular responses of cells from haemopoietic tissue to low dose/low LET radiation

    Energy Technology Data Exchange (ETDEWEB)

    Munira A Kadhim

    2010-03-05

    To accurately define the risks associated with human exposure to relevant environmental doses of low LET ionizing radiation, it is necessary to completely understand the biological effects at very low doses (i.e., less than 0.1 Gy), including the lowest possible dose, that of a single electron track traversal. At such low doses, a range of studies have shown responses in biological systems which are not related to the direct interaction of radiation tracks with DNA. The role of these “non-targeted” responses in critical tissues is poorly understood and little is known regarding the underlying mechanisms. Although critical for dosimetry and risk assessment, the role of individual genetic susceptibility in radiation risk is not satisfactorily defined at present. The aim of the proposed grant is to critically evaluate radiation-induced genomic instability and bystander responses in key stem cell populations from haemopoietic tissue. Using stem cells from two mouse strains (CBA/H and C57BL/6J) known to differ in their susceptibility to radiation effects, we plan to carefully dissect the role of genetic predisposition on two non-targeted radiation responses in these models; the bystander effect and genomic instability, which we believe are closely related. We will specifically focus on the effects of low doses of low LET radiation, down to doses approaching a single electron traversal. Using conventional X-ray and γ-ray sources, novel dish separation and targeted irradiation approaches, we will be able to assess the role of genetic variation under various bystander conditions at doses down to a few electron tracks. Irradiations will be carried out using facilities in routine operation for bystander targeted studies. Mechanistic studies of instability and the bystander response in different cell lineages will focus initially on the role of cytokines which have been shown to be involved in bystander signaling and the initiation of instability. These studies also aim

  19. Personal radiation monitoring and assessment of doses received by radiation workers (1996)

    Energy Technology Data Exchange (ETDEWEB)

    Morris, N.D.

    1996-12-01

    Since late 1986, all persons monitored by the Australian Radiation Laboratory have been registered on a data base which maintains records of the doses received by each individual wearer. At present, the Service regularly monitors approximately 30,000 persons, which is roughly 90 percent of those monitored in Australia, and maintains dose histories of over 75,000 people. The skin dose for occupationally exposed workers can be measured by using one of the five types of monitor issued by the Service: Thermoluminescent Dosemeter (TLD monitor), Finger TLD 3, Neutron Monitor, Special TLD and Environmental monitor. The technical description of the monitors is provided along with the method for calculating the radiation dose. 5 refs., 7 tabs., 5 figs.

  20. Comparison of image quality and radiation dose between an image-intensifier system and a newer-generation flat-panel detector system - technical phantom measurements and evaluation of clinical imaging in children

    Energy Technology Data Exchange (ETDEWEB)

    Weis, Meike; Hagelstein, Claudia; Diehm, Theo; Schoenberg, Stefan O.; Neff, K.W. [University Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Institute of Clinical Radiology and Nuclear Medicine, Mannheim (Germany)

    2016-02-15

    Many image-intensifier fluoroscopy systems have been replaced by flat-panel detectors in recent years. To compare the level of contrast, image resolution and radiation dose between an image-intensifier and a newer-generation flat-panel detector system in a pediatric radiology unit. We compared two systems - a conventional image intensifier and a newer-generation flat-panel system. We measured image quality and radiation dose using a technical phantom. Additionally, we retrospectively compared age-matched fluoroscopic pediatric voiding cystourethrography (n = 15) and upper gastrointestinal investigations (n = 25). In phantom studies image contrast was equal while image resolution was higher and mean radiation dose lower using the flat-panel system (P < 0.0001). In pediatric investigations, mean dose area product was significantly reduced on the flat-panel system for upper gastrointestinal investigation (45 ± 38 μGy*m{sup 2} vs. 11 ± 9 μGy*m{sup 2}; P < 0.0001) and for voiding cystourethrography (18 ± 20 μGy*m{sup 2} vs. 10 ± 12 μGy*m{sup 2}; P = 0.04). The newer flat-panel system performs at lower dose levels with equal to better image quality and therefore seems to be the more suitable technique for pediatric fluoroscopy in comparison to image-intensifier systems. (orig.)

  1. Cerebrovascular Diseases in Childhood Cancer Survivors: Role of the Radiation Dose to Willis Circle Arteries

    Energy Technology Data Exchange (ETDEWEB)

    El-Fayech, Chiraz; Haddy, Nadia; Allodji, Rodrigue Sètchéou; Veres, Cristina; Diop, Fara; Kahlouche, Amar; Llanas, Damien; Jackson, Angela; Rubino, Carole; Guibout, Catherine [Inserm U1018, Villejuif (France); Gustave Roussy, Villejuif (France); University of Paris XI, Villejuif (France); Pacquement, Hélène [Institut Curie, Paris (France); Oberlin, Odile [Gustave Roussy, Villejuif (France); Thomas-Teinturier, Cécile [Inserm U1018, Villejuif (France); Hôpital Bicêtre, Le Kremlin Bicêtre (France); Scarabin, Pierre-Yves [Inserm U1018, Villejuif (France); Chavaudra, Jean; Lefkopoulos, Dimitry [Gustave Roussy, Villejuif (France); Giroud, Maurice; Bejot, Yannick [Registre Dijonnais des accidents vasculaires cérébraux, Dijon (France); Bernier, Valérie [Centre Alexis Vautrin, Vandoeuvre-lès-Nancy (France); Carrie, Christian [Centre Léon Bérard, Lyon (France); and others

    2017-02-01

    Background and Purpose: The aim of this study was to investigate the role of radiation dose received to the circle of Willis (WC) during radiation therapy (RT) and of potential dose-response modifiers on the risk of stroke after treatment of childhood cancer. Methods: We evaluated the risk factors for stroke in a cohort of 3172 5-year survivors of childhood cancer who were followed up for a median time of 26 years. Radiation doses to the WC and brain structures were estimated for each of the 2202 children who received RT. Results: Fifty-four patients experienced a confirmed stroke; 39 were ischemic. Patients not receiving RT had a stroke risk similar to that of the general population, whereas those who received RT had an 8.5-fold increased risk (95% confidence interval [CI]: 6.3-11.0). The excess of incidence of stroke increased yearly. The dose of radiation to the WC, rather than to other brain structures, was found to be the best predictor of stroke. The relative risk was 15.7 (95% CI: 4.9-50.2) for doses of 40 Gy or more. At 45 years of age, the cumulative stroke incidence was 11.3% (95% CI: 7.1%-17.7%) in patients who received 10 Gy or more to the WC, compared with 1% expected from general population data. Radiation doses received to the heart and neck also increased the risk. Surgery for childhood brain cancer was linked to hemorrhagic strokes in these patients. Conclusion: The WC should be considered as a major organ at risk during RT for childhood brain cancers. The incidence of radiation-induced ischemic stroke strongly increases with long-term follow-up.

  2. Analysis of enhancement at small and large radiation doses for effectiveness of inactivation in cultured cells by combining two agents with radiation

    NARCIS (Netherlands)

    Franken, Nicolaas A. P.; Kok, H. Petra; Crezee, Johannes; Barendsen, Gerrit W.

    2016-01-01

    To evaluate the enhancement effect of two combined radiation-sensitizing agents in mammalian cells at small doses as compared to large doses using the linear-quadratic (LQ) mathematical model. Data on clonogenic assays concerning the radio-enhancement effects of combined halogenated pyrimidines and

  3. Radiation optic neuropathy and retinopathy with low dose (20 Gy radiation treatment

    Directory of Open Access Journals (Sweden)

    Crandall E. Peeler

    2016-10-01

    Conclusions and importance: Though cumulative radiation doses to the anterior visual pathway of less than 50 Gy are traditionally felt to be safe, it is important to consider not just the total exposure but also the size of individual fractions. The single-dose threshold for RON in proton beam treatment has yet to be defined. Our case suggests that fractions of less than 10 Gy should be delivered to minimize the risk of optic nerve injury.

  4. RADIATION PROTECTION CABIN FOR CATHETER-DIRECTED LIVER INTERVENTIONS: OPERATOR DOSE ASSESSMENT.

    Science.gov (United States)

    Maleux, Geert; Bergans, Niki; Bosmans, Hilde; Bogaerts, Ria

    2016-09-01

    The number and complexity of interventional radiological procedures and in particular catheter-directed liver interventions have increased substantially. The current study investigates the reduction of personal doses when using a dedicated radiation protection cabin (RPC) for these procedures. Operator and assistant doses were assessed for 3 series of 20 chemoinfusion/chemoembolisation interventions, including an equal number of procedures with and without RPC. Whole body doses, finger doses and doses at the level of knees and eyes were evaluated with different types of TLD-100 Harshaw dosemeters. Dosemeters were also attached on the three walls of the RPC. The operator doses were significantly reduced by the RPC, but also without RPC, the doses appear to be limited as a result of thorough optimisation with existing radiation protection tools. The added value of the RPC should thus be determined by the outcome of balancing dose reduction and other aspects such as ergonomic benefits. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Acute Radiation Risk and BRYNTRN Organ Dose Projection Graphical User Interface

    Science.gov (United States)

    Cucinotta, Francis A.; Hu, Shaowen; Nounu, Hateni N.; Kim, Myung-Hee

    2011-01-01

    The integration of human space applications risk projection models of organ dose and acute radiation risk has been a key problem. NASA has developed an organ dose projection model using the BRYNTRN with SUM DOSE computer codes, and a probabilistic model of Acute Radiation Risk (ARR). The codes BRYNTRN and SUM DOSE are a Baryon transport code and an output data processing code, respectively. The risk projection models of organ doses and ARR take the output from BRYNTRN as an input to their calculations. With a graphical user interface (GUI) to handle input and output for BRYNTRN, the response models can be connected easily and correctly to BRYNTRN. A GUI for the ARR and BRYNTRN Organ Dose (ARRBOD) projection code provides seamless integration of input and output manipulations, which are required for operations of the ARRBOD modules. The ARRBOD GUI is intended for mission planners, radiation shield designers, space operations in the mission operations directorate (MOD), and space biophysics researchers. BRYNTRN code operation requires extensive input preparation. Only a graphical user interface (GUI) can handle input and output for BRYNTRN to the response models easily and correctly. The purpose of the GUI development for ARRBOD is to provide seamless integration of input and output manipulations for the operations of projection modules (BRYNTRN, SLMDOSE, and the ARR probabilistic response model) in assessing the acute risk and the organ doses of significant Solar Particle Events (SPEs). The assessment of astronauts radiation risk from SPE is in support of mission design and operational planning to manage radiation risks in future space missions. The ARRBOD GUI can identify the proper shielding solutions using the gender-specific organ dose assessments in order to avoid ARR symptoms, and to stay within the current NASA short-term dose limits. The quantified evaluation of ARR severities based on any given shielding configuration and a specified EVA or other mission

  6. Prostate Specific Antigen (PSA as Predicting Marker for Clinical Outcome and Evaluation of Early Toxicity Rate after High-Dose Rate Brachytherapy (HDR-BT in Combination with Additional External Beam Radiation Therapy (EBRT for High Risk Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Thorsten H. Ecke

    2016-11-01

    Full Text Available High-dose-rate brachytherapy (HDR-BT with external beam radiation therapy (EBRT is a common treatment option for locally advanced prostate cancer (PCa. Seventy-nine male patients (median age 71 years, range 50 to 79 with high-risk PCa underwent HDR-BT following EBRT between December 2009 and January 2016 with a median follow-up of 21 months. HDR-BT was administered in two treatment sessions (one week interval with 9 Gy per fraction using a planning system and the Ir192 treatment unit GammaMed Plus iX. EBRT was performed with CT-based 3D-conformal treatment planning with a total dose administration of 50.4 Gy with 1.8 Gy per fraction and five fractions per week. Follow-up for all patients was organized one, three, and five years after radiation therapy to evaluate early and late toxicity side effects, metastases, local recurrence, and prostate-specific antigen (PSA value measured in ng/mL. The evaluated data included age, PSA at time of diagnosis, PSA density, BMI (body mass index, Gleason score, D’Amico risk classification for PCa, digital rectal examination (DRE, PSA value after one/three/five year(s follow-up (FU, time of follow-up, TNM classification, prostate volume, and early toxicity rates. Early toxicity rates were 8.86% for gastrointestinal, and 6.33% for genitourinary side effects. Of all treated patients, 84.81% had no side effects. All reported complications in early toxicity were grade 1. PSA density at time of diagnosis (p = 0.009, PSA on date of first HDR-BT (p = 0.033, and PSA on date of first follow-up after one year (p = 0.025 have statistical significance on a higher risk to get a local recurrence during follow-up. HDR-BT in combination with additional EBRT in the presented design for high-risk PCa results in high biochemical control rates with minimal side-effects. PSA is a negative predictive biomarker for local recurrence during follow-up. A longer follow-up is needed to assess long-term outcome and toxicities.

  7. Prostate Specific Antigen (PSA) as Predicting Marker for Clinical Outcome and Evaluation of Early Toxicity Rate after High-Dose Rate Brachytherapy (HDR-BT) in Combination with Additional External Beam Radiation Therapy (EBRT) for High Risk Prostate Cancer.

    Science.gov (United States)

    Ecke, Thorsten H; Huang-Tiel, Hui-Juan; Golka, Klaus; Selinski, Silvia; Geis, Berit Christine; Koswig, Stephan; Bathe, Katrin; Hallmann, Steffen; Gerullis, Holger

    2016-11-10

    High-dose-rate brachytherapy (HDR-BT) with external beam radiation therapy (EBRT) is a common treatment option for locally advanced prostate cancer (PCa). Seventy-nine male patients (median age 71 years, range 50 to 79) with high-risk PCa underwent HDR-BT following EBRT between December 2009 and January 2016 with a median follow-up of 21 months. HDR-BT was administered in two treatment sessions (one week interval) with 9 Gy per fraction using a planning system and the Ir192 treatment unit GammaMed Plus iX. EBRT was performed with CT-based 3D-conformal treatment planning with a total dose administration of 50.4 Gy with 1.8 Gy per fraction and five fractions per week. Follow-up for all patients was organized one, three, and five years after radiation therapy to evaluate early and late toxicity side effects, metastases, local recurrence, and prostate-specific antigen (PSA) value measured in ng/mL. The evaluated data included age, PSA at time of diagnosis, PSA density, BMI (body mass index), Gleason score, D'Amico risk classification for PCa, digital rectal examination (DRE), PSA value after one/three/five year(s) follow-up (FU), time of follow-up, TNM classification, prostate volume, and early toxicity rates. Early toxicity rates were 8.86% for gastrointestinal, and 6.33% for genitourinary side effects. Of all treated patients, 84.81% had no side effects. All reported complications in early toxicity were grade 1. PSA density at time of diagnosis (p = 0.009), PSA on date of first HDR-BT (p = 0.033), and PSA on date of first follow-up after one year (p = 0.025) have statistical significance on a higher risk to get a local recurrence during follow-up. HDR-BT in combination with additional EBRT in the presented design for high-risk PCa results in high biochemical control rates with minimal side-effects. PSA is a negative predictive biomarker for local recurrence during follow-up. A longer follow-up is needed to assess long-term outcome and toxicities.

  8. Radiation effects on livestock: physiological effects, dose response.

    Science.gov (United States)

    Bell, M C

    1985-06-01

    Farm livestock show no measurable effects from being exposed to ionizing radiation unless the level is greatly in excess of the natural background radiation. Possible sources of ionizing radiation which might affect livestock or contribute to radioactivity in the food chain to humans are reactor accidents, fuel reprocessing plant accidents and thermonuclear explosions. Most data on ionizing radiation effects on livestock are from whole body gamma doses near the LD 50/60 level. However, grazing livestock would be subjected to added beta exposure from ingested and skin retained radioactive particles. Results of attempts to simulate exposure of the Hereford cattle at Alamogardo, NM show that cattle are more sensitive to ingested fallout radiation than other species. Poultry LD 50/60 for gamma exposure is about twice the level for mammals, and swine appear to have the most efficient repair system being able to withstand the most chronic gamma exposure. Productivity of most livestock surviving an LD 50/60 exposure is temporarily reduced and longterm effects are small. Livestock are good screeners against undesirables in our diet and with the exception of radiosotopes of iodine in milk, very little fission product radioactivity would be expected to be transferred through the food chain in livestock products for humans. Feeding of stored feed or moving livestock to uncontaminated pastures would be the best protective action to follow.

  9. Has the use of computers in radiation therapy improved the accuracy in radiation dose delivery?

    Science.gov (United States)

    Van Dyk, J.; Battista, J.

    2014-03-01

    Purpose: It is well recognized that computer technology has had a major impact on the practice of radiation oncology. This paper addresses the question as to how these computer advances have specifically impacted the accuracy of radiation dose delivery to the patient. Methods: A review was undertaken of all the key steps in the radiation treatment process ranging from machine calibration to patient treatment verification and irradiation. Using a semi-quantitative scale, each stage in the process was analysed from the point of view of gains in treatment accuracy. Results: Our critical review indicated that computerization related to digital medical imaging (ranging from target volume localization, to treatment planning, to image-guided treatment) has had the most significant impact on the accuracy of radiation treatment. Conversely, the premature adoption of intensity-modulated radiation therapy has actually degraded the accuracy of dose delivery compared to 3-D conformal radiation therapy. While computational power has improved dose calibration accuracy through Monte Carlo simulations of dosimeter response parameters, the overall impact in terms of percent improvement is relatively small compared to the improvements accrued from 3-D/4-D imaging. Conclusions: As a result of computer applications, we are better able to see and track the internal anatomy of the patient before, during and after treatment. This has yielded the most significant enhancement to the knowledge of "in vivo" dose distributions in the patient. Furthermore, a much richer set of 3-D/4-D co-registered dose-image data is thus becoming available for retrospective analysis of radiobiological and clinical responses.

  10. Thyroid Radiation Dose to Patients from Diagnostic Radiology Procedures over Eight Decades: 1930-2010.

    Science.gov (United States)

    Chang, Lienard A; Miller, Donald L; Lee, Choonsik; Melo, Dunstana R; Villoing, Daphnée; Drozdovitch, Vladimir; Thierry-Chef, Isabelle; Winters, Sarah J; Labrake, Michael; Myers, Charles F; Lim, Hyeyeun; Kitahara, Cari M; Linet, Martha S; Simon, Steven L

    2017-12-01

    considerable uncertainties associated with the presented doses, particularly for characterizing exposures of individual identified patients. Nonetheless, the tabulations provide the only comprehensive report on the estimation of typical radiation doses to the thyroid gland from medical diagnostic procedures over eight decades (1930-2010). These data can serve as a resource for epidemiologic studies that evaluate the late health effects of radiation exposure associated with diagnostic radiologic examinations.

  11. A single institution study of radiation dose received from CT imaging: A comparison to Malaysian NDRL

    Science.gov (United States)

    Osman, N. D.; Shamsuri, S. B. M.; Tan, Y. W.; Razali, M. A. S. M.; Isa, S. M.

    2017-05-01

    Advancement of CT technology has led to an increase in CT scanning as it improves the diagnosis. However, it is important to assess health risk of patients associated with ionising radiation received from CT. This study evaluated current dose distributions at Advanced Medical and Dental Institute (AMDI), Malaysia and was used to establish Local Diagnostic Reference Level (LDRL). Dose indicators such as CT Dose Index (CTDIvol and CTDIw) and Dose-Length Product (DLP) were gathered for all routine CT examinations performed at the Imaging Unit, AMDI from January 2015 to June 2016. The first and third quartile values for each dose indicator were determined. A total of 364 CT studies were performed during that period with the highest number of cases being Thorax-Abdomen-Pelvis (TAP) study (57% of total study). The CTDIw ranged between 2.0 mGy to 23.4 mGy per procedure. DLP values were ranged between 94 mGy.cm to 1687 mGy.cm. The local dose data was compared with the national DRL to monitor the current CT practice at AMDI and LDRL will be established from the calculated third quartile values of dose distribution. From the results, some of the local dose values exceeded the Malaysian and further evaluation is important to ensure the dose optimisation for patients.

  12. Measurement of spatial dose distribution for evaluation operator dose during nero-interventional procedures

    Energy Technology Data Exchange (ETDEWEB)

    Han, Su Chul [Division of Medical Radiation Equipment, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Hong, Dong Hee [Dept. of Radiology Science, Far East University, Eumseong (Korea, Republic of)

    2016-09-15

    The spatial dose distribution was measured with ionization chamber as preliminary study to evaluate operator dose and to study dose reduction during neuro-interventional procedures. The zone of operators was divided into four area (45, 135, 225, and 315 degree).We supposed that operator exist on the four area and indicated location of critical organs(eyes, breast, gonad). The spatial doses were measured depending on distance( 80, 100, 120, and 140 cm) and location of critical organs. The spatial doses of area of 225 degree were 114.5 mR/h (eyes location), 143.1 mR/h (breast location) and 147 mR/h (gonad location) in 80 cm. When changed location of x-ray generator, spatial dose increased in 18.1±10.5%, averagely. We certified spatial dose in the operator locations, Using the results of this study, It is feasible to protect operator from radiation in neuro-interventional procedures.

  13. Preoperative Single-Fraction Partial Breast Radiation Therapy: A Novel Phase 1, Dose-Escalation Protocol With Radiation Response Biomarkers

    Energy Technology Data Exchange (ETDEWEB)

    Horton, Janet K., E-mail: janet.horton@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Blitzblau, Rachel C.; Yoo, Sua [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Geradts, Joseph [Department of Pathology, Duke University Medical Center, Durham, North Carolina (United States); Chang, Zheng [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Baker, Jay A. [Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States); Georgiade, Gregory S. [Department of Surgery, Duke University Medical Center, Durham, North Carolina (United States); Chen, Wei [Department of Bioinformatics: Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina (United States); Siamakpour-Reihani, Sharareh; Wang, Chunhao [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Broadwater, Gloria [Department of Biostatistics: Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina (United States); Groth, Jeff [Department of Pathology, Duke University Medical Center, Durham, North Carolina (United States); Palta, Manisha; Dewhirst, Mark [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Barry, William T. [Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina (United States); Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Duffy, Eileen A. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); and others

    2015-07-15

    Purpose: Women with biologically favorable early-stage breast cancer are increasingly treated with accelerated partial breast radiation (PBI). However, treatment-related morbidities have been linked to the large postoperative treatment volumes required for external beam PBI. Relative to external beam delivery, alternative PBI techniques require equipment that is not universally available. To address these issues, we designed a phase 1 trial utilizing widely available technology to 1) evaluate the safety of a single radiation treatment delivered preoperatively to the small-volume, intact breast tumor and 2) identify imaging and genomic markers of radiation response. Methods and Materials: Women aged ≥55 years with clinically node-negative, estrogen receptor–positive, and/or progesterone receptor–positive HER2−, T1 invasive carcinomas, or low- to intermediate-grade in situ disease ≤2 cm were enrolled (n=32). Intensity modulated radiation therapy was used to deliver 15 Gy (n=8), 18 Gy (n=8), or 21 Gy (n=16) to the tumor with a 1.5-cm margin. Lumpectomy was performed within 10 days. Paired pre- and postradiation magnetic resonance images and patient tumor samples were analyzed. Results: No dose-limiting toxicity was observed. At a median follow-up of 23 months, there have been no recurrences. Physician-rated cosmetic outcomes were good/excellent, and chronic toxicities were grade 1 to 2 (fibrosis, hyperpigmentation) in patients receiving preoperative radiation only. Evidence of dose-dependent changes in vascular permeability, cell density, and expression of genes regulating immunity and cell death were seen in response to radiation. Conclusions: Preoperative single-dose radiation therapy to intact breast tumors is well tolerated. Radiation response is marked by early indicators of cell death in this biologically favorable patient cohort. This study represents a first step toward a novel partial breast radiation approach. Preoperative radiation should

  14. Radiation dose optimization in the decommissioning plan for Loviisa NPP

    Energy Technology Data Exchange (ETDEWEB)

    Holmberg, R.; Eurajoki, T. [Nuclear Power Engineering (Finland)

    1995-03-01

    Finnish rules for nuclear power require a detailed decommissioning plan to be made and kept up to date already during plant operation. The main reasons for this {open_quotes}premature{close_quotes} plan, is, firstly, the need to demonstrate the feasibility of decommissioning, and, secondly, to make realistic cost estimates in order to fund money for this future operation. The decomissioning for Lovissa Nuclear Power Plant (NPP) (2{times}445 MW, PWR) was issued in 1987. It must be updated about every five years. One important aspect of the plant is an estimate of radiation doses to the decomissioning workers. The doses were recently re-estimated because of a need to decrease the total collective dose estimate in the original plan, 23 manSv. In the update, the dose was reduced by one-third. Part of the reduction was due to changes in the protection and procedures, in which ALARA considerations were taken into account, and partly because of re-estimation of the doses.

  15. The influence of high doses of radiation in citrine stones

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M. I. [Universidade Nove de Julho - UNINOVE, Rua Vergueiro 235/249, 01504-001 Sao Paulo (Brazil); Caldas, L. V. E., E-mail: miteixeira@ipen.br [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

    2014-08-15

    The possibility of using samples of Brazilian stones as quartz, amethyst, topaz, jasper, etc. for high-dose dosimetry has been studied in recent years at IPEN, using the techniques of optical absorption (Oa), thermoluminescent (Tl), optically stimulated luminescence (OSL) and resonance paramagnetic electron (EPR). In this work, the Tl properties of citrine samples were studied. They were exposed to different doses of gamma radiation ({sup 60}Co). The natural citrine stone was extracted from a mine in Minas Gerais state, Brazil; it is a tecto silicate ranked as one of three-dimensional structure, showing clear yellow to golden brown color. The natural citrine stone is classified as quartz (SiO{sub 2}), and it has a lower symmetry and more compact reticulum. The Tl emission curve showed two peaks at 160 grades C and 220 grades C. To remove the Tl peak (160 grades C) of the sintered citrine pellet glow curves, different thermal treatments were tested during several time intervals. The Tl dose-response curve between 50 Gy and 100 kGy, the reproducibility of Tl response and the lower detection dose were obtained. The results show that citrine may be useful as high-dose detectors. (Author)

  16. Terrestrial Gamma Radiation Dose Rate of West Sarawak

    Science.gov (United States)

    Izham, A.; Ramli, A. T.; Saridan Wan Hassan, W. M.; Idris, H. N.; Basri, N. A.

    2017-10-01

    A study of terrestrial gamma radiation (TGR) dose rate was conducted in west of Sarawak, covering Kuching, Samarahan, Serian, Sri Aman, and Betong divisions to construct a baseline TGR dose rate level data of the areas. The total area covered was 20,259.2 km2, where in-situ measurements of TGR dose rate were taken using NaI(Tl) scintillation detector Ludlum 19 micro R meter NaI(Tl) approximately 1 meter above ground level. Twenty-nine soil samples were taken across the 5 divisions covering 26 pairings of 9 geological formations and 7 soil types. A hyperpure Germanium detector was then used to find the samples' 238U, 232Th, and 40K radionuclides concentrations producing a correction factor Cf = 0.544. A total of239 measured data were corrected with Cf resulting in a mean Dm of 47 ± 1 nGy h-1, with a range between 5 nGy h-1 - 103 nGy h-1. A multiple regression analysis was conducted between geological means and soil types means against the corrected TGR dose rate Dm, generating Dg,s= 0.847Dg+ 0.637Ds- 22.313 prediction model with a normalized Beta equation of Dg,s= 0.605Dg+ 0.395Ds. The model has an 84.6% acceptance of Whitney- Mann test null hypothesis when tested against the corrected TGR dose rates.

  17. Does the lead apron and collar always reduce radiation dose?

    Science.gov (United States)

    Nortje, C J; Harris, A M; Lackovic, K P; Wood, R E

    2001-11-01

    The possibility that personal lead shielding devices can increase absorption of radiation has not been entertained. The purpose of the present investigation specifically was to determine whether pituitary dose might be increased when a leaded apron and thyroid collar are used. Thermoluminescent dosimeters (TLDs) were used to measure absorbed dose. They were calibrated at the kVp used in the clinical situation and a calibration curve relating light output to dose was generated. Lithium fluoride TLD discs were placed in the pituitary gland region of a Rando-Alderson female human phantom. The equivalent of 100 transpharyngeal exposures were delivered. The resultant light output from recovered dosimeters was converted to a uGy value using the calibration curve. The experiment was repeated using a 0.25 mm lead equivalent collar and apron fitted to the phantom in the customary manner. The entire process was repeated in order to have 30 dosimeters for the unshielded and 30 dosimeters for the shielded conditions. A further 30 dosimeters were sham irradiated and served as controls. A statistical comparison between unshielded and shielded conditions was performed. When the leaded apron and thyroid collar were used the absorbed dose to the pituitary gland was increased significantly (P < 0.05). Following this a second group, using a different dosimetry system and a male phantom repeated the experiment. In both cases, the shielded phantom received significantly higher dose to the pituitary region than the unshielded.

  18. Correlation of clinical outcome to the estimated radiation dose from Boron Neutron Capture Therapy (BNCT)

    Energy Technology Data Exchange (ETDEWEB)

    Chadha, M. [Beth Israel Medical Center, NY (United States). Dept. of Radiation Oncology; Coderre, J.A.; Chanana, A.D. [Brookhaven National Lab., Upton, NY (United States)] [and others

    1996-12-31

    A phase I/II trial delivering a single fraction of BNCT using p-Boronophenylalanine-Fructose and epithermal neutrons at the the Brookhaven Medical Research Reactor was initiated in September 1994. The primary endpiont of the study was to evaluate the feasibility and safety of a given BNCT dose. The clinical outcome of the disease was a secondary endpoint of the study. The objective of this paper is to evaluate the correlation of the clinical outcome of patients to the estimated radiation dose from BNCT.

  19. Patient absorbed radiation doses estimation related to irradiation anatomy; Estimativa de dose absorvida pelo paciente relacionada a anatomia irradiada

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes, E-mail: prof.flavio@gmail.com, E-mail: amanda-a-soares@hotmail.com, E-mail: gabriellygkahl@gmail.com [Instituto Federal de Eduacao, Ciencia e Tecnologia de Santa Catarina (IFSC), Florianopolis, SC (Brazil)

    2014-07-01

    Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector.

  20. Topical Metered-dosing Dispenser Performance Evaluation.

    Science.gov (United States)

    Liu, Qiang; Kupiec, Thomas C; Vu, Nicole T

    2016-01-01

    Topical metered-dosing dispensers are designed for dosing accuracy and ease-of-use by the patients while protecting the packaged products from environmental exposure and contamination. The objective of this study was to evaluate the accuracy, precision, and residual of available topical metered-dosing dispensers with different types of topical cream for practical application. Triplicate samples of five different dispensers were tested. This test was completed using three types of commercial topical cream-bases of dissimilar Total Active Pharmaceutical Ingredient Load Percentages, Transdermal Penetration Percentages, and Specific Gravities. The dispensers were evaluated according to specified dose-uniformity criteria for a total dispensing capacity of 30 mL at 0.5 mL per dose for 60 doses. The study shows Topi-CLICK performed with the best precision and accuracy of dosing in comparison to the airless-pump type dispensers. While the dispensing was highly variable with airless pumps and may require calibration for each packaged product, remarkably the performance of Topi-CLICK was not affected by different types of cream-bases and does not require additional metering calibration. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

  1. Total dose radiation failure probability of bipolar transistors

    CERN Document Server

    Chen Pan Xun

    2002-01-01

    The failure probability P sub F related with gamma total dose radiation is presented for three bipolar transistor 3DK9D, 3DG6D and 3DG4C. It is shown that the P sub F -D relation is well depicted by Weibull function. h sub F sub E (D)/h sub F sub E (0)=80%, 70% and 50% was taken as the failure criteria for transistors. The experimental results have shown that distributing curves depend on failure criteria. The P sub F -D curves are comprised of two straights with different slopes. It means that there were devices with different technology in the samples. The total dose radiation characteristic is displayed by the failure distributing slope. It is used for quality surveillance of device hardening processes. While the P sub F -D straights are extrapolated to lower P sub F , the failure total dose was only several tens Gy for the failure probabilities being 0.1% and 0.01% in some devices

  2. Estimation of radiation doses for workers without monitoring data for retrospective epidemiologic studies

    Energy Technology Data Exchange (ETDEWEB)

    Watson, J.E. Jr. [Univ. of North Carolina, Chapel Hill, NC (United States); Tankersley, W.G.; West, C.M. [Oak Ridge Institute of Science and Education, TN (United States)

    1994-10-01

    Dosimetry data are required for many epidemiologic studies of radiation workers. For several reasons, these data may not be available for some workers for some periods of time. An estimate of a worker`s dose for such a time period can be made using data from nearby time periods for the worker or using data obtained for other workers during the same time period. This paper reports the results of an evaluation of a procedure for estimating external doses for workers included in retrospective epidemiologic studies. This evaluation was conducted using data for workers who had recorded doses for each year in a 5-y period. The dose for the middle year of the 5-y period was treated as unavailable and the dose was estimated several ways. These estimates were compared with the recorded dose. It was observed that averaging a worker`s dose data for the years preceding and following a year for which data hypothetically were not available most often yielded the best estimate for a dose than was the department or facility median or mean dose. However, at another facility, use of the department median or mean dose produced a more accurate estimate than did nearby data for the worker. These results indicate that a single procedure for estimating doses is not best for all facilities, and it is recommended that a test of the type reported in this paper be performed before a decision is made on how to estimate doses. The use of department medians or means to estimate doses consistently produced better estimates than were obtained using facility medians or means. 1 ref., 4 tabs.

  3. Roles of radiation dose and chemotherapy in the etiology of stomach cancer as a second malignancy

    DEFF Research Database (Denmark)

    van den Belt-Dusebout, Alexandra W; Aleman, Berthe M P; Besseling, Gijs

    2009-01-01

    PURPOSE: To evaluate the roles of radiation dose, chemotherapy, and other factors in the etiology of stomach cancer in long-term survivors of testicular cancer or Hodgkin lymphoma. METHODS AND MATERIALS: We conducted a cohort study in 5,142 survivors of testicular cancer or Hodgkin lymphoma treated...... in the Netherlands between 1965 and 1995. In a nested case-control study, detailed information on treatment, smoking, gastrointestinal diseases, and family history was collected for 42 patients with stomach cancer and 126 matched controls. For each subject, the mean radiation dose to the stomach was estimated....... Relative risks (RRs) of stomach cancer and the radiation-related excess relative risk (ERR) per gray were calculated by conditional logistic regression analysis. RESULTS: The risk of stomach cancer was 3.4-fold increased compared with the general population. The risk increased with increasing mean stomach...

  4. CT evaluation of living liver donor: Can 100-kVp plus iterative reconstruction protocol provide accurate liver volume and vascular anatomy for liver transplantation with reduced radiation and contrast dose?

    Science.gov (United States)

    Yoshida, Morikatsu; Utsunomiya, Daisuke; Kidoh, Masafumi; Yuki, Hideaki; Oda, Seitaro; Shiraishi, Shinya; Yamamoto, Hidekazu; Inomata, Yukihiro; Yamashita, Yasuyuki

    2017-06-01

    We evaluated whether donor computed tomography (CT) with a combined technique of lower tube voltage and iterative reconstruction (IR) can provide sufficient preoperative information for liver transplantation.We retrospectively reviewed CT of 113 liver donor candidates. Dynamic contrast-enhanced CT of the liver was performed on the following protocol: protocol A (n = 70), 120-kVp with filtered back projection (FBP); protocol B (n = 43), 100-kVp with IR. To equalize the background covariates, one-to-one propensity-matched analysis was used. We visually compared the score of the hepatic artery (A-score), portal vein (P-score), and hepatic vein (V-score) of the 2 protocols and quantitatively correlated the graft volume obtained by CT volumetry (graft-CTv) under the 2 protocols with the actual graft weight.In total, 39 protocol-A and protocol-B candidates showed comparable preoperative clinical characteristics with propensity matching. For protocols A and B, the A-score was 3.87 ± 0.73 and 4.51 ± 0.56 (P Liver-donor CT imaging under 100-kVp plus IR protocol provides better visualization for vascular structures than that under 120-kVp plus FBP protocol with comparable accuracy for graft-CTv, while lowering radiation exposure by more than 40% and reducing contrast-medium dose by 20%.

  5. Dose-volume analysis of radiation-induced trismus in head and neck cancer patients.

    Science.gov (United States)

    Gebre-Medhin, Maria; Haghanegi, Mahnaz; Robért, Lotta; Kjellén, Elisabeth; Nilsson, Per

    2016-11-01

    Trismus is a treatment-related late side effect in patients treated for cancer in the head and neck region (HNC). The condition can have a considerable negative impact on nutrition, dental hygiene, ability to speak and quality of life. We have previously studied trismus within the frame of a randomized phase 3 study of HNC patients treated with mainly three-dimensional (3D) conformal radiotherapy (CRT) and found a strong association to mean radiation dose to the mastication muscles, especially the ipsilateral masseter muscle (iMAS). In the present study we have investigated trismus prevalence and risk factors in a more recent cohort of patients, treated with todays' more updated radiation techniques. Maximal interincisal distance (MID) was measured on 139 consecutive patients. Trismus was defined as MID ≤35 mm. Patient-, disease- and treatment-specific data were retrospectively recorded. Differences between groups were analyzed and mean absorbed dose to mastication structures was evaluated. Dosimetric comparisons were made between this study and our previous results. The prevalence of trismus was 24% at a median of 16 months after completion of radiotherapy. In bivariate analysis treatment technique (3DCRT vs. intensity modulated radiotherapy or helical tomotherapy), tumor site (oropharynx vs. other sites) and mean radiation doses to the ipsilateral lateral pterygoid muscle, the paired masseter muscles and the iMAS were significantly associated with MID ≤35 mm. In multivariable analysis only mean radiation dose to the iMAS was significantly associated to MID ≤35 mm. Mean radiation dose to the ipsilateral masseter muscle is an important risk factor for trismus development. Dose reduction to this structure during radiotherapy should have a potential to diminish the prevalence of trismus in this patient group.

  6. Cardiovascular CT angiography in neonates and children : Image quality and potential for radiation dose reduction with iterative image reconstruction techniques

    NARCIS (Netherlands)

    Tricarico, Francesco; Hlavacek, Anthony M.; Schoepf, U. Joseph; Ebersberger, Ullrich; Nance, John W.; Vliegenthart, Rozemarijn; Cho, Young Jun; Spears, J. Reid; Secchi, Francesco; Savino, Giancarlo; Marano, Riccardo; Schoenberg, Stefan O.; Bonomo, Lorenzo; Apfaltrer, Paul

    To evaluate image quality (IQ) of low-radiation-dose paediatric cardiovascular CT angiography (CTA), comparing iterative reconstruction in image space (IRIS) and sinogram-affirmed iterative reconstruction (SAFIRE) with filtered back-projection (FBP) and estimate the potential for further dose

  7. Collective dose as a performance measure for occupational radiation protection programs: Issues and recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Strom, D.J.; Harty, R.; Hickey, E.E.; Martin, J.B.; Peffers, M.S. [Pacific Northwest National Lab., Richland, WA (United States); Kathren, R.L. [Washington State Univ., Pullman, WA (United States)

    1998-07-01

    Collective dose is one of the performance measures used at many US Department of Energy (DOE) contractor facilities to quantitatively assess the objectives of the radiation protection program. It can also be used as a management tool to improve the program for keeping worker doses as low as reasonably achievable (ALARA). Collective dose is used here to mean the sum of all total effective dose equivalent values for all workers in a specified group over a specified time. It is often used as a surrogate estimate of radiological risk. In principle, improvements in radiation protection programs and procedures will result in reduction of collective dose, all other things being equal. Within the DOE, most frequently, a single collective dose number, which may or may not be adjusted for workload and other factors, is used as a performance measure for a contractor. The purpose of this report is to evaluate the use of collective dose as a performance measure for ALARA programs at DOE sites.

  8. Bolus effect to reduce skin dose of the caontralateral breast during breast cancer radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Won, Young Jin [Dept. of Radiation Oncology, InJe University Ilsan Paik Hospital, Goyang (Korea, Republic of); Kim, Jong Won; Kim, Jung Hoon [Dept. of Radiology, Radiation Oncology, KonYang University Hospital, Daejeon (Korea, Republic of)

    2017-06-15

    The aim of this study was to evaluate the dose comparison using Radon phantom with 5 mm and 10 mm tissue equivalent materials, FIF, Wedge(15, 30 angle) and IMRT, to reduce the skin dose of the contralateral breast during breast cancer radiation therapy(Total dose: 50.4Gy). The dose was measured for each treatment plan by attaching to the 8 point of the contralateral breast of the treated region using a optical-stimulated luminance dosimeter(OSLD) as a comparative dose evaluation method. Of the OSLD used in the study, 10 were used with reproducibility within 3%. As a result, the average reduction rates of 5 mm and 10 mm in the FIF treatment plan were 37.23 cGy and 41.77 cGy, respectively, and the average reduction rates in the treatment plan using Wedge 15 degrees were 70.69 cGy and 87.57 cGy, respectively. The IMRT showed a reduction of 67.37 cGy and 83.17 cGy, respectively. The results of using bolus showed that as the thickness of the bolus increased in all treatments, the dose reduction increased. We concluded that mastectomy as well as general radiotherapy for breast cancer would be very effective for patients who are more likely to be exposed to scattered radiation due to a more demanding or complex treatment plan.

  9. Radiation doses in patients under full-mouth radiographic examination; Doses em pacientes submetidos a exames radiologicos de boca completa

    Energy Technology Data Exchange (ETDEWEB)

    Hazin, C.; Khoury, Helen; Silveira, Sueldo [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear; Silveira, Marcia [Universidade de Pernambuco, Recife, PE (Brazil). Faculdade de Odontologia

    1996-12-31

    Radiation doses received by tissues of the head and neck as a result of a full-mouth radiographic examination are studied. Simulations are carried out by irradiating the head and neck section of an anthropomorphic phantom. The radiation doses are determined through the use of thermoluminescent dosimeters 1 ref., 2 tabs.

  10. Perspectives on radiation dose estimates for A-bomb survivors

    Energy Technology Data Exchange (ETDEWEB)

    Loewe, W.E.

    1986-12-01

    Four decades after the actual events, quantitative characterization of the radiation fields at Hiroshima and Nagasaki continues to be sought, with high accuracy a goal justified by the unique contribution to radiation protection standards that is represented by the medical records of exposed survivors. The most recent effort is distinguished by its reliance on computer modeling and concomitant detail, and by its decentralized direction, both internationally and internally to the US and Japan, with resultant ongoing peer review and wide scope of inquiry. A new system for individual dose estimation has been agreed upon, and its scientific basis has been elaborated in the literature as well as in a comprehensive treatise to be published in the Spring of 1987. In perspective, this new system appears to be an unusually successful achievement that offers the expectation of reliable estimates with the desired accuracy. Some aspects leading to this expectation, along with a caveat, are discussed here. 4 refs., 8 figs., 3 tabs.

  11. Hardening electronic devices against very high total dose radiation environments

    Science.gov (United States)

    Buchanan, B.; Shedd, W.; Roosild, S.; Dolan, R.

    1972-01-01

    The possibilities and limitations of hardening silicon semiconductor devices to the high neutron and gamma radiation levels and greater than 10 to the eighth power rads required for the NERVA nuclear engine development are discussed. A comparison is made of the high dose neutron and gamma hardening potential of bipolar, metal insulator semiconductors and junction field effect transistors. Experimental data is presented on device degradation for the high neutron and gamma doses. Previous data and comparisons indicate that the JFET is much more immune to the combined neutron displacement and gamma ionizing effects than other transistor types. Experimental evidence is also presented which indicates that p channel MOS devices may be able to meet the requirements.

  12. Exposure to low dose ionising radiation: Molecular and clinical consequences.

    LENUS (Irish Health Repository)

    Martin, Lynn M

    2014-07-10

    This review article provides a comprehensive overview of the experimental data detailing the incidence, mechanism and significance of low dose hyper-radiosensitivity (HRS). Important discoveries gained from past and present studies are mapped and highlighted to illustrate the pathway to our current understanding of HRS and the impact of HRS on the cellular response to radiation in mammalian cells. Particular attention is paid to the balance of evidence suggesting a role for DNA repair processes in the response, evidence suggesting a role for the cell cycle checkpoint processes, and evidence investigating the clinical implications\\/relevance of the effect.

  13. 3D measurement of absolute radiation dose in grid therapy

    Science.gov (United States)

    Trapp, J. V.; Warrington, A. P.; Partridge, M.; Philps, A.; Leach, M. O.; Webb, S.

    2004-01-01

    Spatially fractionated radiotherapy through a grid is a concept which has a long history and was routinely used in orthovoltage radiation therapy in the middle of last century to minimize damage to the skin and subcutaneous tissue. With the advent of megavoltage radiotherapy and its skin sparing effects the use of grids in radiotherapy declined in the 1970s. However there has recently been a revival of the technique for use in palliative treatments with a single fraction of 10 to 20 Gy. In this work the absolute 3D dose distribution in a grid irradiation is measured for photons using a combination of film and gel dosimetry.

  14. Radiation dose reduction with hybrid iterative reconstruction for pediatric CT.

    Science.gov (United States)

    Singh, Sarabjeet; Kalra, Mannudeep K; Shenoy-Bhangle, Anuradha S; Saini, Aashna; Gervais, Debra A; Westra, Sjirk J; Thrall, James H

    2012-05-01

    To assess image quality and radiation dose reduction with hybrid iterative reconstruction of pediatric chest and abdominal computed tomographic (CT) data compared with conventional filtered back projection (FBP). A total of 234 patients (median age, 12 years; age range, 6 weeks to 18 years) underwent chest and abdominal CT in this institutional review board-approved HIPAA-compliant retrospective study. CT was performed with a hybrid adaptive statistical iterative reconstruction (ASIR)-enabled 64-detector row CT scanner. Scanning protocols were adjusted for clinical indication and patient weight to enable acquisition of reduced-dose CT images in all patients, and tube current was further lowered for ASIR protocols. Weight, age, and sex were recorded, and objective noise was measured in the descending thoracic aorta for chest CT and in the liver for abdominal CT. Of the 234 consecutive patients who underwent ASIR-enabled CT (115 chest and 119 abdominal examinations), 70 patients had undergone prior FBP CT. ASIR and FBP CT studies (29 chest and 41 abdominal studies) in these 70 patients were reviewed for image quality, artifacts, and diagnostic confidence by two pediatric radiologists working independently. Data were analyzed with multiple paired t tests. Compared with FBP, ASIR enabled dose reduction of 46.4% (3.7 vs 6.9 mGy) for chest CT and 38.2% (5.0 vs 8.1 mGy) for abdominal CT (P ASIR and FBP CT images as acceptable, without any artifacts. Despite the lower radiation dose used, ASIR images (chest, 10.7 ± 2.5 [mean ± standard deviation]; abdomen, 11.8 ± 3.4) had substantially less objective noise than did FBP images (chest, 13.3 ± 3.8; abdomen, 13.8 ± 5.2) (P = .001, P =.006, respectively). Use of a hybrid iterative reconstruction technique, such as ASIR, enables substantial radiation dose reduction for pediatric CT when compared with FBP and maintains image quality and diagnostic confidence.

  15. Th Cell Gene Expression and Function in Response to Low Dose and Acute Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Daila S. Gridley, PhD

    2012-03-30

    FINAL TECHNICAL REPORT Supported by the Low Dose Radiation Research Program, Office of Science U.S. Department of Energy Grant No. DE-FG02-07ER64345 Project ID: 0012965 Award Register#: ER64345 Project Manager: Noelle F. Metting, Sc.D. Phone: 301-903-8309 Division SC-23.2 noelle.metting@science.doe.gov Submitted March 2012 To: https://www.osti.gov/elink/241.3.jsp Title: Th Cell Gene Expression and Function in Response to Low Dose and Acute Radiation PI: Daila S. Gridley, Ph.D. Human low dose radiation data have been derived primarily from studies of space and airline flight personnel, nuclear plant workers and others exposed occupationally, as well as victims in the vicinity of atomic bomb explosions. The findings remain inconclusive due to population inconsistencies and complex interactions among total dose, dose rate, radiation quality and age at exposure. Thus, safe limits for low dose occupational irradiation are currently based on data obtained with doses far exceeding the levels expected for the general population and health risks have been largely extrapolated using the linear-nonthreshold dose-response model. The overall working hypothesis of the present study is that priming with low dose, low-linear energy transfer (LET) radiation can ameliorate the response to acute high-dose radiation exposure. We also propose that the efficacy of low-dose induced protection will be dependent upon the form and regimen of the high-dose exposure: photons versus protons versus simulated solar particle event protons (sSPE). The emphasis has been on gene expression and function of CD4+ T helper (Th) lymphocytes harvested from spleens of whole-body irradiated C57BL/6 mice, a strain that provides the genetic background for many genetically engineered strains. Evaluations of the responses of other selected cells, tissues such as skin, and organs such as lung, liver and brain were also initiated (partially funded by other sources). The long-term goal is to provide information

  16. Comparative evaluations of individual radiation doses at hospital environment in two decades 73-82 and 86-95; Estudo comparativo de duas decadas, 73-82 e 86-95, de monitoracao individual hospitalar

    Energy Technology Data Exchange (ETDEWEB)

    Carreira, Mauricio Costa; Almeida, Adelaide de [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica; Sordi, Gian Maria A.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Santos, Maria Concepta P.S. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas

    1996-12-31

    Individual radiation doses in two decades of Hospital das Clinicas, Ribeirao Preto, Sao Paulo State, Brazil, are analysed. The annual values are studied according to the hospital service and specific worker categories. The workers are classified in categories A or B as recommended by ICRP 35. Three types of individual monitors (film badges, Ca So{sub 4} and Li F + Ca So{sub 4}) supplied by three distinct laboratories are compared 6 refs., 1 fig.

  17. Ruthenium-106 brachytherapy for thick uveal melanoma: reappraisal of apex and base dose radiation and dose rate

    Directory of Open Access Journals (Sweden)

    Masood Naseripour

    2016-02-01

    Full Text Available Purpose: To evaluate the outcomes of ruthenium-106 ( 106 Ru brachytherapy in terms of radiation parameters in patients with thick uveal melanomas. Material and methods: Medical records of 51 patients with thick (thickness ≥ 7 mm and < 11 mm uveal melanoma treated with 106 Ru brachytherapy during a ten-year period were reviewed. Radiation parameters, tumor regression, best corrected visual acuity (BCVA, and treatment-related complications were assessed. Results: Fifty one eyes of 51 consecutive patients including 25 men and 26 women with a mean age of 50.5 ± 15.2 years were enrolled. Patients were followed for 36.1 ± 26.5 months (mean ± SD. Mean radiation dose to tumor apex and to sclera were 71 (± 19.2 Gy and 1269 (± 168.2 Gy. Radiation dose rates to tumor apex and to sclera were 0.37 (± 0.14 Gy/h and 6.44 (± 1.50 Gy/h. Globe preservation was achieved in 82.4%. Preoperative mean tumor thickness of 8.1 (± 0.9 mm decreased to 4.5 (± 1.6 mm, 3.4 (± 1.4 mm, and 3.0 (± 1.46 mm at 12, 24, and 48 months after brachytherapy (p = 0.03. Four eyes that did not show regression after 6 months of brachytherapy were enucleated. Secondary enucleation was performed in 5 eyes because of tumor recurrence or neovascular glaucoma. Tumor recurrence was evident in 6 (11.8% patients. Mean Log MAR (magnification requirement visual acuity declined from 0.75 (± 0.63 to 0.94 (± 0.5 (p = 0.04. Best corrected visual acuity of 20/200 or worse was recorded in 37% of the patients at the time of diagnosis and 61.7% of the patients at last exam (p = 0.04. Non-proliferative and proliferative radiation-induced retinopathy was observed in 20 and 7 eyes. Conclusions : Thick uveal melanomas are amenable to 106 Ru brachytherapy with less than recommended apex radiation dose and dose rates.

  18. Supplementary comparison CCRI(I)-S2 of standards for absorbed dose to water in 60Co gamma radiation at radiation processing dose levels

    DEFF Research Database (Denmark)

    Burns, D. T.; Allisy-Roberts, P. J.; Desrosiers, M. F.

    2011-01-01

    Eight national standards for absorbed dose to water in 60Co gamma radiation at the dose levels used in radiation processing have been compared over the range from 1 kGy to 30 kGy using the alanine dosimeters of the NIST and the NPL as the transfer dosimeters. The comparison was organized by the B...

  19. CT imaging of congenital lung lesions: effect of iterative reconstruction on diagnostic performance and radiation dose.

    Science.gov (United States)

    Haggerty, Jay E; Smith, Ethan A; Kunisaki, Shaun M; Dillman, Jonathan R

    2015-07-01

    Different iterative reconstruction techniques are available for use in pediatric computed tomography (CT), but these techniques have not been systematically evaluated in infants. To determine the effect of iterative reconstruction on diagnostic performance, image quality and radiation dose in infants undergoing CT evaluation for congenital lung lesions. A retrospective review of contrast-enhanced chest CT in infants (reconstruction method. CTDIvol was used to calculate size-specific dose estimates (SSDE). CT findings were correlated with intraoperative and histopathological findings. Analysis of variance and the Student's t-test were used to compare image noise measurements and radiation dose estimates between groups. Fifteen CT examinations used filtered back projection (FBP; mean age: 84 days), 15 used adaptive statistical iterative reconstruction (ASiR; mean age: 93 days), and 11 used model-based iterative reconstruction (MBIR; mean age: 98 days). Compared to operative findings, 13/15 (87%), 14/15 (93%) and 11/11 (100%) lesions were correctly characterized using FBP, ASiR and MBIR, respectively. Arterial anatomy was correctly identified in 12/15 (80%) using FBP, 13/15 (87%) using ASiR and 11/11 (100%) using MBIR. Image noise was less for MBIR vs. ASiR (P iterative CT reconstruction techniques while maintaining image quality and lowering radiation dose.

  20. Injury of the blood-testies barrier after low-dose-rate chronic radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Young Hoon; Bae Min Ji; Lee, Chang Geun; Yang, Kwang Mo; Jur, Kyu; Kim, Jong Sun [Dongnam Institute of Radiological and Medical Science, Busan (Korea, Republic of)

    2014-04-15

    The systemic effect of radiation increases in proportionally with the dose and dose rate. Little is known concerning the relationships between harmful effects and accumulated dose, which is derived from continuous low-dose rate radiation exposure. Recent our studies show that low-dose-rate chronic radiation exposure (3.49 mGy/h) causes adverse effects in the testis at a dose of 2 Gy (6 mGy/h). However, the mechanism of the low-dose-rate 2 Gy irradiation induced testicular injury remains unclear. The present results indicate that low-dose rate chronic radiation might affect the BTB permeability, possibly by decreasing levels of ZO-1, Occludin-1, and NPC-2. Furthermore, our results suggest that there is a risk of male infertility through BTB impairment even with low-dose-rate radiation if exposure is continuous.

  1. Reproducibility of semi-automatic coronary plaque quantification in coronary CT angiography with sub-mSv radiation dose

    DEFF Research Database (Denmark)

    Øvrehus, Kristian Altern; Schuhbaeck, Annika; Marwan, Mohamed

    2015-01-01

    or response to medical therapies. The reproducibility from repeated assessment of such quantitative measurements from low-radiation dose coronary CTA has not been previously assessed. Purpose: To evaluate the interscan, interobserver and intraobserver reproducibility for coronary plaque volume assessment...... using semi-automatic plaque analyses algorithm in low radiation dose coronary CTA. Methods: In 50 consecutive patients undergoing two 128-slice dual source CT scans within 12 days with a mean radiation dose of 0.7 mSv per coronary CTA, the interscan, interobserver and intraobserver reproducibility.......6% and +/- 32.1%, respectively. Conclusion: A semi-automatic plaque assessment algorithm in repeated low radiation dose coronary CTA allows for high reproducibility of coronary plaque characterization and quantification measures. (C) 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc...

  2. A Comparative Evaluation of Normal Tissue Doses for Patients Receiving Radiation Therapy for Hodgkin Lymphoma on the Childhood Cancer Survivor Study and Recent Children's Oncology Group Trials

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Rachel; Ng, Angela [Department of Radiation Therapy, Princess Margaret Cancer Centre, Toronto, Ontario (Canada); Constine, Louis S. [Department of Radiation Oncology, University of Rochester, Rochester, New York (United States); Stovall, Marilyn [Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Armstrong, Gregory T. [Epidemiology/Cancer Control Department, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Neglia, Joseph P. [Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota (United States); Friedman, Debra L. [Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee (United States); Kelly, Kara [Division of Pediatric Hematology/Oncology/Stem Cell Transplant, Department of Pediatrics, Columbia University Medical Center, New York, New York (United States); FitzGerald, Thomas J. [Department of Radiation Oncology, University of Massachusetts Medical School, Worcester, Massachusetts (United States); Imaging and Radiation Oncology Core Group, Lincoln, Rhode Island (United States); Hodgson, David C., E-mail: David.hodgson@rmp.uhn.on.ca [Department of Radiation Oncology, University of Toronto, and Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada)

    2016-06-01

    Purpose: Survivors of pediatric Hodgkin lymphoma (HL) are recognized to have an increased risk of delayed adverse health outcomes related to radiation therapy (RT). However, the necessary latency required to observe these late effects means that the estimated risks apply to outdated treatments. We sought to compare the normal tissue dose received by children treated for HL and enrolled in the Childhood Cancer Survivor Study (CCSS) (diagnosed 1970-1986) with that of patients treated in recent Children's Oncology Group (COG) trials (enrolled 2002-2012). Methods and Materials: RT planning data were obtained for 50 HL survivors randomly sampled from the CCSS cohort and applied to computed tomography planning data sets to reconstruct the normal tissue dosimetry. For comparison, the normal tissue dosimetry data were obtained for all 191 patients with full computed tomography–based volumetric RT planning on COG protocols AHOD0031 and AHOD0831. Results: For early-stage patients, the mean female breast dose in the COG patients was on average 83.5% lower than that for CCSS patients, with an absolute reduction of 15.5 Gy. For advanced-stage patients, the mean breast dose was decreased on average by 70% (11.6 Gy average absolute dose reduction). The mean heart dose decreased on average by 22.9 Gy (68.6%) and 17.6 Gy (56.8%) for early- and advanced-stage patients, respectively. All dose comparisons for breast, heart, lung, and thyroid were significantly lower for patients in the COG trials than for the CCSS participants. Reductions in the prescribed dose were a major contributor to these dose reductions. Conclusions: These are the first data quantifying the significant reduction in the normal tissue dose using actual, rather than hypothetical, treatment plans for children with HL. These findings provide useful information when counseling families regarding the risks of contemporary RT.

  3. The impact of pediatric-specific dose modulation curves on radiation dose and image quality in head computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Joana; Paulo, Graciano [Instituto Politecnico de Coimbra, ESTESC, DMIR, Coimbra (Portugal); Foley, Shane; Rainford, Louise [University College Dublin, School of Medicine and Medical Science, Health Science Centre, Dublin 4 (Ireland); McEntee, Mark F. [The University of Sydney, Faculty of Health Sciences, Cumberland Campus, Sydney (Australia)

    2015-11-15

    The volume of CT examinations has increased with resultant increases in collective dose values over the last decade. To analyze the impact of the tube current and voltage modulation for dose values and image quality of pediatric head CT examinations. Head CT examinations were performed on anthropomorphic phantoms and four pediatric age categories before and after the introduction of dedicated pediatric curves for tube voltage and current modulation. Local diagnostic reference levels were calculated. Visual grading characteristic image quality evaluation was performed by four pediatric neuroradiologists and image noise comparisons were performed. Pediatric-specific modulation curves demonstrated a 49% decrease in mean radiation dose for phantom examinations. The local diagnostic reference levels (CTDIvol) for clinical examinations decreased by 52%, 41%, 46% and 40% for newborn, 5-, 10- and 15-year-old patients, respectively. Visual grading characteristic image quality was maintained for the majority of age categorizations (area under the curve = 0.5) and image noise measurements did not change (P = 0.693). Pediatric-specific dose modulation curves resulted in an overall mean dose reduction of 45% with no significant differences in subjective or objective image quality findings. (orig.)

  4. AAPM/RSNA Physics Tutorial for Residents: Topics in CT. Radiation dose in CT.

    Science.gov (United States)

    McNitt-Gray, Michael F

    2002-01-01

    This article describes basic radiation dose concepts as well as those specifically developed to describe the radiation dose from computed tomography (CT). Basic concepts of radiation dose are reviewed, including exposure, absorbed dose, and effective dose. Radiation dose from CT demonstrates variations within the scan plane and along the z axis because of its unique geometry and usage. Several CT-specific dose descriptors have been developed: the Multiple Scan Average Dose descriptor, the Computed Tomography Dose Index (CTDI) and its variations (CTDI(100), CTDI(w), CTDI(vol)), and the dose-length product. Factors that affect radiation dose from CT include the beam energy, tube current-time product, pitch, collimation, patient size, and dose reduction options. Methods of reducing the radiation dose to a patient from CT include reducing the milliampere-seconds value, increasing the pitch, varying the milliampere-seconds value according to patient size, and reducing the beam energy. The effective dose from CT can be estimated by using Monte Carlo methods to simulate CT of a mathematical patient model, by estimating the energy imparted to the body region being scanned, or by using conversion factors for general anatomic regions. Issues related to radiation dose from CT are being addressed by the Society for Pediatric Radiology, the American Association of Physicists in Medicine, the American College of Radiology, and the Center for Devices and Radiological Health of the Food and Drug Administration. Copyright RSNA, 2002

  5. FT-IR spectroscopy assessment of aesthetic dental materials irradiated with low-dose therapeutic ionizing radiation

    Science.gov (United States)

    Cruz, A. D.; Almeida, S. M.; Rastelli, A. N. S.; Bagnato, V. S.; Byscolo, F. N.

    2009-03-01

    The aim of the present study was to evaluate the effects of low-dose therapeutic ionizing radiation on different aesthetic dental materials. Forty five specimens ( n = 45) of three different aesthetic restorative materials were prepared and randomly divided into five groups: G1 (control group); G2, G3, G4, G5 experimental groups irradiated respectively with 0.25, 0.50, 0.75, and 1.00 Gy of gamma radiation by the 60Co teletherapy machine. Chemical analyses were performed using a FT-IR Nicolet 520 spectrophotometer with reflectance diffuse technique. Even a minimal exposition at ionizing radiation in therapeutic doses can provide chemical changes on light-cured composite resins. The three studied restorative materials showed changes after exposure at gamma radiation, however the increase of the radiation dose did not contribute to an increase in this effect.

  6. Increased radiation dose at mammography due to prolonged exposure, delayed processing, and increased film darkening.

    Science.gov (United States)

    Kimme-Smith, C; Bassett, L W; Gold, R H; Chow, S

    1991-02-01

    Four single-emulsion films introduced over the past 2 years--Du Pont Microvision, Fuji MiMa, Konica CM, and Eastman Kodak OM--were compared with Eastman Kodak OM SO-177 (Min-RE) film to evaluate their varying effects on mean glandular dose of reciprocity law failure due to prolonged exposure, delayed processing, and increased film darkening as a result of increased radiation exposure to improve penetration of glandular tissue. Exposures over 1.3 seconds led to increased radiation doses of 20%-30%. Delays in processing of 6 hours decreased processing speed by 11%-32% for all films except Du Pont Microvision. Optical density increases of 0.40 required 20%-30% more skin exposure for all five films. Optimal viewing densities were also evaluated and found to be different for each of the five films. Mammographers need to be aware of these differences in mammographic films to achieve maximum contrast at mammography.

  7. Increased radiation dose at mammography due to prolonged exposure, delayed processing, and increased film darkening

    Energy Technology Data Exchange (ETDEWEB)

    Kimme-Smith, C.; Bassett, L.W.; Gold, R.H.; Chow, S. (UCLA Medical Center (USA))

    1991-02-01

    Four single-emulsion films introduced over the past 2 years--Du Pont Microvision, Fuji MiMa, Konica CM, and Eastman Kodak OM--were compared with Eastman Kodak OM SO-177 (Min-RE) film to evaluate their varying effects on mean glandular dose of reciprocity law failure due to prolonged exposure, delayed processing, and increased film darkening as a result of increased radiation exposure to improve penetration of glandular tissue. Exposures over 1.3 seconds led to increased radiation doses of 20%-30%. Delays in processing of 6 hours decreased processing speed by 11%-32% for all films except Du Pont Microvision. Optical density increases of 0.40 required 20%-30% more skin exposure for all five films. Optimal viewing densities were also evaluated and found to be different for each of the five films. Mammographers need to be aware of these differences in mammographic films to achieve maximum contrast at mammography.

  8. Recent topics on radon. Radiation dose estimation using radon

    Energy Technology Data Exchange (ETDEWEB)

    Shimo, Michikuni [National Inst. of Radiological Sciences, Chiba (Japan)

    1998-05-01

    Today, as exposure of radon was collected a large interest in resident environment, it was brought by a fact that yearly radiation dose of radon was determined 1.0 mSv in the report of UN science committee in 1982. Since then, as this value was received generally and widely, this value was found some differences due to thereafter UN science committee reports and to some countings. As not only concentration of radon but also some factors relate to its cause, it is important to know its cause and variation width. In this paper, by using the newest data in Japan on radon concentration, balance factor, presence time, respiration volume, and so forth as much as possible, an effective radiation dose of an adult per year was estimated. As a result, it was found to be about 0.45 mSv, which was more than a half less than the value of the UN science committee and so on. And, this was nearly equal to that of workers at 3 prefectures of that Tokai District and counted by using radon concentration, respiration volume and presence coefficient for variants. On counting the whole variation width under considering width of each coefficient, it can be estimated to be ranged from -70 to +80%. (G.K.)

  9. Radon Release and Its Simulated Effect on Radiation Doses.

    Science.gov (United States)

    Orabi, Momen

    2017-03-01

    One of the main factors that affect the uncertainty in calculating the gamma-radiation absorbed dose rate inside a room is the variation in the degree of secular equilibrium of the considered radioactive series. A component of this factor, considered in this paper, is the release of radon (Rn) from building materials to the living space of the room. This release takes place through different steps. These steps are represented and mathematically formulated. The diffusion of radon inside the material is described by Fick's second law. Some of the factors affecting the radon release rate (e.g. covering walls, moisture, structure of the building materials, etc.) are discussed. This scheme is used to study the impact of radon release on the gamma-radiation absorbed dose rate inside a room. The investigation is carried out by exploiting the MCNP simulation software. Different building materials are considered with different radon release rates. Special care is given to Rn due to its relatively higher half-life and higher indoor concentration than the other radon isotopes. The results of the presented model show that the radon release is of a significant impact in some building materials.

  10. Controlled platform for the radiation dose data measured in Radiation controlled area of KOMAC

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Kyun; Min, Yi Sub; Park, Jeong Min; Cho, Yong Sub [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Korea multi-purpose accelerator complex (KOMAC), the branch institute of Korea atomic energy research institute (KAERI), is a multi-user facility to provide a high-intensity proton beam with the energy from 20 MeV to the 100 MeV. This proton beam is accelerated via the proton linear accelerator that is comprised of a 50-keV injector, 3-MeV radio frequency quadrupole (RFQ), and 100-MeV drift tube linac (DTL). The KOMAC site is classified into General public area and Radiation controlled area, according to the dose rate of 0.25 μSv/h. The system for the data made in Radiation controlled area should have the database to save and the data in the database could be expressed on the monitor in the any form which user wants. The control platform to satisfy these conditions will be made on the basis of the Qt program and MYSQL program. The place with the maximum average values about the alpha and beta detected is the entrance of Radiation controlled area. However, their values are very small in comparison to the criteria to decide the contamination area in KOMAC. That is, KOMAC is safe from the radioactive contamination. The reason why the radiation dose value is twice the background value in Klystron gallery is the klystron to generate the radiation. However, actually the klystron gallery is controlled by the control room when the proton beam is accelerated.

  11. Development of radiation fusion technology with food technology by the application of high dose irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Juwoon; Kim, Jaehun; Choi, Jongil; and others

    2012-04-15

    This study was performed to achieve stable food supply and food safety with radiation fusion technology as a preparation for food weaponization. Results at current stage are following: First, for the development of radiation and food engineering fusion technology using high dose irradiation, the effects of high dose irradiation on food components were evaluated. The combination treatment of irradiation with food engineering was developed. Irradiation condition to destroy radiation resistant foodborne bacteria were determined. Second, for the development of E-beam irradiation technology, the effects of radiation sources on food compounds, processing conditions, and food quality of final products were compared. Food processing conditions for agricultural/aquatic products with different radiation sources was developed and the domination of E-beam irradiation foods were determined. The physical marker for E-beam irradiated foods or not was developed. Third, for the fundamental researches to develop purposed foods to extreme environmental, ready-to-eat foods were developed using high dose irradiation. Food processing for export strategy foods such as process ginseng were developed. Food processing with irradiation to destroy mycotoxin and to inhibit production of mycotoxin was developed. Mathematical models to predict necessary irradiation doses and radiation sources were developed and validated. Through the fundamental researches, the legislation for irradiation approval on meat products, sea foods and dried sea foods, and use of E-beam was introduced. Results from this research project, the followings are expected. Improvement of customer acceptance and activation of irradiation technology by the use of various irradiation rays. Increase of indirect food productivity, and decrease of SOC and improvement of public health by prevention of foodborne outbreaks. Build of SPS/TBT system against imported products and acceleration of domestic product export. Systemized

  12. Development of Radiation Fusion Technology with Food Technology by the Application of High Dose Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Won; Kim, Jae Hun; Choi, Jong Il

    2010-04-15

    This study was studied to achieve stable food supply and food safety with radiation fusion technology as a preparation for food weaponization. Results at current stage are following: First, for the development of radiation and food engineering fusion technology using high dose irradiation, the effects of high dose irradiation on food components were evaluated. The combination treatment of irradiation with food engineering were developed. Irradiation condition to destroy radiation resistant food borne bacteria were determined. Second, for the development of E-beam irradiation technology, the effects of radiation sources on food compounds, processing conditions, and food quality of final products were compared. Food processing conditions for agricultural/aquatic products with different radiation sources were developed and the domination of E-beam irradiation foods were determined. The physical marker for E-beam irradiated foods or not were developed. Third, for the fundamental researches to develop purposed foods to extreme environmental, ready-to-eat foods were developed using high dose irradiation. Food processing for export strategy foods such as process ginseng were developed. Food processing with irradiation to destroy mycotoxin and to inhibit production of mycotoxin were developed. Mathematical models to predict necessary irradiation doses and radiation sources were developed and validated. Through the fundamental researches, the legislation for irradiation approval on meat products, sea foods and dried sea foods, and use of E-beam were introduced. Results from this research project, the followings are expected. (1) Improvement of customer acceptance and activation of irradiation technology by the use of various irradiation rays. (2) Increase of indirect food productivity, and decrease of SOC and improvement of public health by prevention of food borne outbreaks. (3) Build of SPS/TBT system against imported products and acceleration of domestic product export

  13. Effects of low doses of ionizing radiation; Effets des faibles doses de rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Masse, R. [Office de Protection contre les Rayonnements Ionisants, 78 - le Vesinet (France)

    2006-07-01

    Several groups of human have been irradiated by accidental or medical exposure, if no gene defect has been associated to these exposures, some radioinduced cancers interesting several organs are observed among persons exposed over 100 to 200 mSv delivered at high dose rate. Numerous steps are now identified between the initial energy deposit in tissue and the aberrations of cell that lead to tumors but the sequence of events and the specific character of some of them are the subject of controversy. The stake of this controversy is the risk assessment. From the hypothesis called linear relationship without threshold is developed an approach that leads to predict cancers at any tiny dose without real scientific foundation. The nature and the intensity of biological effects depend on the quantity of energy absorbed in tissue and the modality of its distribution in space and time. The probability to reach a target (a gene) associated to the cancerating of tissue is directly proportional to the dose without any other threshold than the quantity of energy necessary to the effect, its probability of effect can be a more complex function and depends on the quality of the damage produced as well as the ability of the cell to repair the damage. These two parameters are influenced by the concentration of initial injuries in the target so by the quality of radiation and by the dose rate. The mechanisms of defence explain the low efficiency of radiation as carcinogen and then the linearity of effects in the area of low doses is certainly the least defensible scientific hypothesis for the prediction of the risks. (N.C.)

  14. Geosciences help to protect human health: estimation of the adsorbed radiation doses while flight journeys, as important step to radiation risk assessment

    Science.gov (United States)

    Chernov, Anatolii; Shabatura, Olexandr

    2016-04-01

    Estimation of the adsorbed radiation dose while flight journeys is a complex problem, which should be solved to get correct evaluation of equivalent effective doses and radiation risk assessment. Direct measurements of the adsorbed dose in the aircrafts during regional flights (3-10 hours) has shown that the radiation in the plane may increase 10-15 times (to 2-4 mSv/h) compared to the values on the surface of the Earth (0.2-0.5 mSv/h). Results of instrumental research confirmed by the other investigations. It is a fact that adsorbed doses per year while flight journeys are less than doses from medical tests. However, while flight journeys passengers get the same doses as nuclear power plant staff, people in zones of natural radiation anomalies and so should be evaluated. According to the authors' research, flight journeys are safe enough, when solar activity is normal and if we fly under altitude of 18 km (as usual, while intercontinental flights). Most of people travel by plane not so often, but if flight is lasting in dangerous periods of solar activity (powerful solar winds and magnetic field storms), passengers and flight crew can adsorb great amount of radiation doses. People, who spend more than 500 hours in flight journeys (pilots, business oriented persons', government representatives, etc.) get amount of radiation, which can negatively influence on health and provoke diseases, such as cancer. Authors consider that problem actual and researches are still going on. It is revealed, that radiation can be calculated, using special equations. Great part of radiation depends on very variable outer-space component and less variable solar. Accurate calculations of doses will be possible, when we will take into account all features of radiation distribution (time, season of year and exact time of the day, duration of flight), technical features of aircraft and logistics of flight (altitude, latitude). Results of first attempts of radiation doses modelling confirmed

  15. Evaluation of surgical gloves for radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Antolin, E.; Rot, M.J.; Ordonez, J.; Arranz, L.; Sastre, J.M.; Ferrer, N.; Andres, J.C. de [Hospital Ramon y Ca jal, Servicio de Radiofisica y Proteccion Radiologica, Madrid (Spain)

    2006-07-01

    Full text of publication follows: Accumulated doses in hands during interventionist cardiology and radiological procedures can reach high values, and even go beyond legal limits for exposed professionals after years of work, unless they use specific radiation protection methods. An important protection mean for hands is the use of surgical gloves that attenuate the radiation while maintaining the tactile sensitivity demanded by physicians.There is a wide variety of commercialized gloves for radiation protection, with different advantages and disadvantages for various uses. In this paper nine different models of gloves have been evaluated for testing its attenuation capacity for several voltages, the maintenance of tactile sensitivity, its resistance to elongation, and the apparition of pores after successive sterilizing processes. It is very important that they do not lose its initial characteristics after processes of sterilization in order to optimize the product effective cost. The attenuation values have been measured under the voltages of 60, 70, 80 and 90 KVp obtaining very different values at each voltage with different gloves. The values measured range between 34 % before any supplementary sterilization with one model of glove (for 90 KVp), and 57 % after four sterilization processes with another glove (for 60 KVp). Some gloves lose its attenuation capacity after successive sterilizations, having not been found an y significant relation with their composition. The tactile sensitivity, a decisive factor for its users, decreases as its attenuation capacity increases, and remains mostly constant after being sterilized. The tests performed allow to conclude a set of fi nal results that can facilitate the choice of the most suitable gloves according to the practical applications (the priorities being the radiation protection and the tactile sensitivity)

  16. Pretreatment of low dose radiation reduces radiation-induced apoptosis in mouse lymphoma (EL4) cells.

    Science.gov (United States)

    Kim, J H; Hyun, S J; Yoon, M Y; Ji, Y H; Cho, C K; Yoo, S Y

    1997-06-01

    Induction of an adaptive response to ionizing radiation in mouse lymphoma (EL4) cells was studied by using cell survival fraction and apoptotic nucleosomal DNA fragmentation as biological end points. Cells in early log phase were pre-exposed to low dose of gamma-rays (0.01 Gy) 4 or 20 hrs prior to high dose gamma-ray (4, 8 and 12 Gy for cell survival fraction analysis; 8 Gy for DNA fragmentation analysis) irradiation. Then cell survival fractions and the extent of DNA fragmentation were measured. Significant adaptive response, increase in cell survival fraction and decrease in the extent of DNA fragmentation were induced when low and high dose gamma-ray irradiation time interval was 4 hr. Addition of protein or RNA synthesis inhibitor, cycloheximide or 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (DRFB), respectively during adaptation period, the period from low dose gamma-ray irradiation to high dose gamma-ray irradiation, was able to inhibit the induction of adaptive response, which is the reduction of the extent DNA fragmentation in irradiated EL4 cells. These data suggest that the induction of adaptive response to ionizing radiation in EL4 cells required both protein and RNA synthesis.

  17. MOSFET assessment of radiation dose delivered to mice using the Small Animal Radiation Research Platform (SARRP).

    Science.gov (United States)

    Ngwa, Wilfred; Korideck, Houari; Chin, Lee M; Makrigiorgos, G Mike; Berbeco, Ross I

    2011-12-01

    The Small Animal Radiation Research Platform (SARRP) is a novel isocentric irradiation system that enables state-of-the-art image-guided radiotherapy research to be performed with animal models. This paper reports the results obtained from investigations assessing the radiation dose delivered by the SARRP to different anatomical target volumes in mice. Surgically implanted metal oxide semiconductor field effect transistors (MOSFET) dosimeters were employed for the dose assessment. The results reveal differences between the calculated and measured dose of -3.5 to 0.5%, -5.2 to -0.7%, -3.9 to 0.5%, -5.9 to 2.5%, -5.5 to 0.5%, and -4.3 to 0% for the left kidney, liver, pancreas, prostate, left lung, and brain, respectively. Overall, the findings show less than 6% difference between the delivered and calculated dose, without tissue heterogeneity corrections. These results provide a useful assessment of the need for tissue heterogeneity corrections in SARRP dose calculations for clinically relevant tumor model sites.

  18. Cardiovascular risks associated with low dose ionizing particle radiation.

    Directory of Open Access Journals (Sweden)

    Xinhua Yan

    Full Text Available Previous epidemiologic data demonstrate that cardiovascular (CV morbidity and mortality may occur decades after ionizing radiation exposure. With increased use of proton and carbon ion radiotherapy and concerns about space radiation exposures to astronauts on future long-duration exploration-type missions, the long-term effects and risks of low-dose charged particle irradiation on the CV system must be better appreciated. Here we report on the long-term effects of whole-body proton ((1H; 0.5 Gy, 1 GeV and iron ion ((56Fe; 0.15 Gy, 1GeV/nucleon irradiation with and without an acute myocardial ischemia (AMI event in mice. We show that cardiac function of proton-irradiated mice initially improves at 1 month but declines by 10 months post-irradiation. In AMI-induced mice, prior proton irradiation improved cardiac function restoration and enhanced cardiac remodeling. This was associated with increased pro-survival gene expression in cardiac tissues. In contrast, cardiac function was significantly declined in (56Fe ion-irradiated mice at 1 and 3 months but recovered at 10 months. In addition, (56Fe ion-irradiation led to poorer cardiac function and more adverse remodeling in AMI-induced mice, and was associated with decreased angiogenesis and pro-survival factors in cardiac tissues at any time point examined up to 10 months. This is the first study reporting CV effects following low dose proton and iron ion irradiation during normal aging and post-AMI. Understanding the biological effects of charged particle radiation qualities on the CV system is necessary both for the mitigation of space exploration CV risks and for understanding of long-term CV effects following charged particle radiotherapy.

  19. Prospective ECG triggering versus low-dose retrospective ECG-gated 128-channel CT coronary angiography: comparison of image quality and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Q.; Yin, Y.; Hua, X.; Zhu, R.; Hua, J. [Department of Radiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Xu, J., E-mail: xujianr@hotmail.co [Department of Radiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China)

    2010-10-15

    Aim: To evaluate image quality and radiation dose for 128-detector prospective electrocardiogram (ECG)-gated computed tomography coronary angiography (CTCA) compared with a low-dose retrospective ECG-gated imaging protocol. Materials and methods: Thirty-one and 47 patients suspected of having coronary artery disease were enrolled into groups examined using prospective and low-dose retrospective ECG-gated CT protocols respectively. All examinations were performed on a 128-detector CT system (Definition AS, Siemens Healthcare, Forchheim, Germany). Prospective CTCA was performed using following parameters: tube voltage 100 kV; tube current 205 mAs; centre of acquisition window 70% of the RR interval. The tube current for low-dose retrospective ECG-gated CTCA was full dose during 40-70% of the RR interval and partial dose for the rest of RR interval. The pitch varied between 0.2 and 0.5 depending on heart rate and patient size. Image quality of coronary arteries was evaluated using a four-point grading scale. The signal-to-noise ratios (SNRs) of enhanced arteries and myocardium were also measured, corresponding contrast-to-noise ratios (CNRs) were calculated, and the radiation doses received were recorded. Results: There was a significant difference in the image quality scores between the retrospective and prospective gating protocols (Chi-square = 15.331, p = 0.009). There was no significant difference between the SNRs of the contrasted artery and myocardium in these two groups, but the CNRs were increased in the prospective group. The mean radiation dose of prospective gating group was 2.71 {+-} 0.67 mSv (range, 1.67-3.59 mSv), which was significantly lower than that of the retrospective group (p < 0.001). Conclusion: Prospective CT angiography can achieve lower radiation dose than that of low-dose retrospective CT angiography, with preserved image quality.

  20. Intensity-Modulated Radiation Therapy Improves the Target Coverage Over 3-D Planning While Meeting Lung Tolerance Doses for All Patients With Malignant Pleural Mesothelioma.

    Science.gov (United States)

    Ulger, Sukran; Cetin, Eren; Catli, Serap; Sarac, Hilal; Kilic, Diclehan; Bora, Huseyin

    2017-06-01

    To investigate high conformality on target coverage and the ability on creating strict lung dose limitation of intensity-modulated radiation therapy in malignant pleural mesothelioma. Twenty-four radiation therapy plannings were evaluated and compared with dosimetric outcomes of conformal radiation therapy and intensity-modulated radiation therapy. Hemithoracal radiation therapy was performed on 12 patients with a fraction of 1.8 Gy to a total dose of 50.4 Gy. All organs at risk were contoured. Radiotherapy plannings were differed according to the technique; conformal radiation therapy was planned with conventionally combined photon-electron fields, and intensity-modulated radiation therapy was planned with 7 to 9 radiation beam angles optimized in inverse planning. Strict dose-volume constraints were applied. Intensity-modulated radiation therapy was statistically superior in target coverage and dose homogeneity (intensity-modulated radiation therapy-planning target volume 95 mean 100%; 3-dimensional conformal radiation therapy-planning target volume 95 mean 71.29%, P = .0001; intensity-modulated radiation therapy-planning target volume 105 mean 11.14%; 3-dimensional conformal radiation therapy-planning target volume 105 mean 35.69%, P = .001). The dosimetric results of the remaining lung was below the limitations on intensity-modulated radiation therapy planning data (intensity-modulated radiation therapy-lung mean dose mean 7.5 [range: 5.6%-8.5%]; intensity-modulated radiation therapy-lung V5 mean 55.55% [range: 47%-59.9%]; intensity-modulated radiation therapy-lung V20 mean 4.5% [range: 0.5%-9.5%]; intensity-modulated radiation therapy-lung V13 mean 13.43% [range: 4.2%-22.9%]). With a complex and large target volume of malignant pleural mesothelioma, intensity-modulated radiation therapy has the ability to deliver efficient tumoricidal radiation dose within the safe dose limits of the remaining lung tissue.

  1. Measurement of patient radiation doses in certain urography procedures.

    Science.gov (United States)

    Sulieman, A; Barakat, H; Zailae, A; Abuderman, A; Theodorou, K

    2015-07-01

    Patients are exposed to significant radiation doses during diagnostic and interventional urologic procedures. This study aimed to measure patient entrance surface air kerma (ESAK) and to estimate the effective dose during intravenous urography (IVU), extracorporeal shock-wave lithotripsy (ESWL), and ascending urethogram (ASU) procedures. ESAK was measured in patients using calibrated thermo luminance dosimeters, GR200A). Effective doses (E) were calculated using the National Radiological Protection Board (NRPB) software. A total of 179 procedures were investigated. 27.9 % of the patients underwent IVU procedures, 27.9 % underwent ESWL procedures and 44.2 % underwent ASU procedures. The mean ESAK was 2.1, 4.18 and 4.9 mGy for IVU, ESWL, and ASU procedures, respectively. Differences in patient ESAK for the same procedure were observed. The mean ESAK values were comparable with those in previous studies. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Comparing different methods for estimating radiation dose to the conceptus

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rendon, X.; Dedulle, A. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); Walgraeve, M.S.; Woussen, S.; Zhang, G. [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Bosmans, H. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Zanca, F. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); GE Healthcare, Buc (France)

    2017-02-15

    To compare different methods available in the literature for estimating radiation dose to the conceptus (D{sub conceptus}) against a patient-specific Monte Carlo (MC) simulation and a commercial software package (CSP). Eight voxel models from abdominopelvic CT exams of pregnant patients were generated. D{sub conceptus} was calculated with an MC framework including patient-specific longitudinal tube current modulation (TCM). For the same patients, dose to the uterus, D{sub uterus}, was calculated as an alternative for D{sub conceptus}, with a CSP that uses a standard-size, non-pregnant phantom and a generic TCM curve. The percentage error between D{sub uterus} and D{sub conceptus} was studied. Dose to the conceptus and percent error with respect to D{sub conceptus} was also estimated for three methods in the literature. The percentage error ranged from -15.9% to 40.0% when comparing MC to CSP. When comparing the TCM profiles with the generic TCM profile from the CSP, differences were observed due to patient habitus and conceptus position. For the other methods, the percentage error ranged from -30.1% to 13.5% but applicability was limited. Estimating an accurate D{sub conceptus} requires a patient-specific approach that the CSP investigated cannot provide. Available methods in the literature can provide a better estimation if applicable to patient-specific cases. (orig.)

  3. Improved image quality and radiation dose reduction in liver dynamic CT scan with the protocol change

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yu Jin; Cho, Pyong Kon [Radiological Science, Catholic University of Daegu, Daegu (Korea, Republic of)

    2015-06-15

    The purpose is reducing radiation dose while maintaining of image quality in liver dynamic CT(LDCT) scan, by protocols generally used and the tube voltage set at a low level protocol compared to the radiation dose and image quality. The target is body mass index, 18.5-24 patients out of 40 patients who underwent the ACT(abdominal CT). Group A(tube voltage : 120 kVp, SAFIRE strength 1) of 20 people among 40 people, to apply the general abdominal CT scan protocol, group B(tube voltage : 100 kVp, apply SAFIRE strength 0-5) was 20 people, set a lower tube voltage. Image quality evaluation was setting a region of interest(ROI) in the liver parenchyma, aorta, superior mesenteric artery (SMA), celiac trunk, visceral fat of arterial phase. In the ROI were compared by measuring the noise, signal to noise ratio(SNR), contrast to noise ratio(CNR), CT number. In addition, qualitative assessments to evaluate two people in the rich professional experience in Radiology by 0-3 points. We compared the total radiation dose, dose length product(DLP) and effective dose, volume computed tomography dose index(CTDIvol). The higher SAFIRE in the tube voltage 100 kVp, noise is reduced, CT number was increased. Thus, SNR and CNR was increased higher the SAFIRE step. Compared with the tube voltage 120 kVp, noise, SNR, CNR was most similar in SAFIRE strength 2 and 3. Qualitative assessment SAFIRE strength 2 is the most common SAFIRE strength 2 the most common qualitative assessment, if the tube voltage of 100 kVp when the quality of the images better evaluated was SAFIRE strength 1. Dose was reduced from 21.69%, in 100 kVp than 120 kVp. In the case of a relatively high BMI is not LDCT scan, When it is shipped from the factory tube voltage is set higher, unnecessary radiation exposure when considering the reality that is concerned, when according to the results of this study, set a lower tube voltage and adjust the SAFIRE strength to 1 or 2, the radiation without compromising image quality

  4. Patient doses and radiation risks in film-screen mammography in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Servomaa, A.; Parviainen, T.; Komppa, T. [Finnish Centre for Radiation and Nuclear Safety (STUK), Helsinki (Finland)

    1995-12-31

    Screen-film mamography is the most sensitive method for the early detection of breast cancer. Breast doses in mamography should be measured for several reasons, especially for the evaluation of patient risk in a screening programme, but also for the assessment and comparison of imaging techniques and equipment performance. In this study, the factors affecting patient doses were assessed by making performance and patient dose measurements; about 50 mammographic units used for screening were included in the study. The lifetime risk as a function of age at exposure was calculated using the average glandular dose, the relative risk model shown in the BEIR V report, and the breast cancer mortality in Finland. The mean surface dose of a 4.5 cm thick phantom was 6.3 mGy, and the mean glandular dose 1.0 mGy. Analysis of the surface dose with respect to film optical density, relative speed of film processing, sensitivity of image receptors, and antiscatter grid showed that the mean surface dose could be decreased by more than 50%. For the screened age group of 50 to 59 years, the risk of exposure-induced death (REID) of breast cancer is about 1.4 x 10{sup -6} mSv{sup -1}, and the average loss of life expectancy due to the radiation-induced breast cancer deaths (LLE/REID) is about 9.5 years. (Author).

  5. Dose computation in conformal radiation therapy including geometric uncertainties: Methods and clinical implications

    Science.gov (United States)

    Rosu, Mihaela

    The aim of any radiotherapy is to tailor the tumoricidal radiation dose to the target volume and to deliver as little radiation dose as possible to all other normal tissues. However, the motion and deformation induced in human tissue by ventilatory motion is a major issue, as standard practice usually uses only one computed tomography (CT) scan (and hence one instance of the patient's anatomy) for treatment planning. The interfraction movement that occurs due to physiological processes over time scales shorter than the delivery of one treatment fraction leads to differences between the planned and delivered dose distributions. Due to the influence of these differences on tumors and normal tissues, the tumor control probabilities and normal tissue complication probabilities are likely to be impacted upon in the face of organ motion. In this thesis we apply several methods to compute dose distributions that include the effects of the treatment geometric uncertainties by using the time-varying anatomical information as an alternative to the conventional Planning Target Volume (PTV) approach. The proposed methods depend on the model used to describe the patient's anatomy. The dose and fluence convolution approaches for rigid organ motion are discussed first, with application to liver tumors and the rigid component of the lung tumor movements. For non-rigid behavior a dose reconstruction method that allows the accumulation of the dose to the deforming anatomy is introduced, and applied for lung tumor treatments. Furthermore, we apply the cumulative dose approach to investigate how much information regarding the deforming patient anatomy is needed at the time of treatment planning for tumors located in thorax. The results are evaluated from a clinical perspective. All dose calculations are performed using a Monte Carlo based algorithm to ensure more realistic and more accurate handling of tissue heterogeneities---of particular importance in lung cancer treatment planning.

  6. A method to adjust radiation dose-response relationships for clinical risk factors

    DEFF Research Database (Denmark)

    Appelt, Ane Lindegaard; Vogelius, Ivan R

    2012-01-01

    Several clinical risk factors for radiation induced toxicity have been identified in the literature. Here, we present a method to quantify the effect of clinical risk factors on radiation dose-response curves and apply the method to adjust the dose-response for radiation pneumonitis for patients...

  7. Comparative transcriptome analysis of rice seedlings induced by different doses of heavy ion radiation

    Science.gov (United States)

    Zhao, Qian; Sun, Yeqing; Wang, Wei

    2016-07-01

    Highly ionizing radiation (HZE) in space is considered as a main factor causing biological effects on plant seeds. To investigate the different effects on genome-wide gene expression of low-dose and high-dose ion radiation, we carried out ground-base carbon particle HZE experiments with different cumulative doses (0Gy, 0.2Gy, 2Gy) to rice seeds and then performed comparative transcriptome analysis of the rice seedlings. We identified a total of 2551 and 1464 differentially expressed genes (DEGs) in low-dose and high-dose radiation groups, respectively. Gene ontology analyses indicated that low-dose and high-dose ion radiation both led to multiple physiological and biochemical activities changes in rice. By Gene Ontology analyses, the results showed that only one process-oxidation reduction process was enriched in the biological process category after high-dose ion radiation, while more processes such as response to biotic stimulus, heme binding, tetrapyrrole binding, oxidoreductase activity, catalytic activity and oxidoreductase activity were significantly enriched after low-dose ion radiation. The results indicated that the rice plants only focused on the process of oxidation reduction to response to high-dose ion radiation, whereas it was a coordination of multiple biological processes to response to low-dose ion radiation. To elucidate the transcriptional regulation of radiation stress-responsive genes, we identified several DEGs-encoding TFs. AP2/EREBP, bHLH, C2H2, MYB and WRKY TF families were altered significantly in response to ion radiation. Mapman analysis speculated that the biological effects on rice seedlings caused by the radiation stress might share similar mechanisms with the biotic stress. Our findings highlight important alterations in the expression of radiation response genes, metabolic pathways, and TF-encoding genes in rice seedlings exposed to low-dose and high-dose ion radiation.

  8. Learning From Trials on Radiation Dose in Non-Small Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, Jeffrey, E-mail: jbradley@wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States); Hu, Chen [Division of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States)

    2016-11-15

    In this issue of the International Journal of Radiation Oncology • Biology • Physics, Taylor et al present a meta-analysis of published data supporting 2 findings: (1) radiation dose escalation seems to benefit patients who receive radiation alone for non-small cell lung cancer; and (2) radiation dose escalation has a detrimental effect on overall survival in the setting of concurrent chemotherapy. The latter finding is supported by data but has perplexed the oncology community. Perhaps these findings are not perplexing at all. Perhaps it is simply another lesson in the major principle in radiation oncology, to minimize radiation dose to normal tissues.

  9. Problems Associated with the Use of the Radiochromic Dye Film as a Radiation Dose Meter

    DEFF Research Database (Denmark)

    Hansen, Johnny; Wille, Mads; Olsen, Kjeld J.

    1984-01-01

    A thorough investigation has been made of the problems involved in using a dye film dose meter for precision dosimetry at high doses, using both low- and high-LET radiation. The study includes: time course of coloration following irradiation at various dose levels; dose response after irradiation...... of coloration. The dose response has been found to depend strongly on: the time span between irradiation and measurement; the irradiation temperature; and the dose rate at doses above 50 kGy for low-LET radiation. Irradiation in vacuum (right-pointing angle bracket1 Pa) and in air produced the same dose...

  10. Assessment of radiation dose in nuclear cardiovascular imaging using realistic computational models

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Tianwu [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211 (Switzerland); Lee, Choonsik [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, Maryland 20852 (United States); Bolch, Wesley E. [Departments of Nuclear and Radiological and Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States); Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211 (Switzerland); Geneva Neuroscience Center, Geneva University, Geneva CH-1205 (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen 9700 RB (Netherlands)

    2015-06-15

    Purpose: Nuclear cardiology plays an important role in clinical assessment and has enormous impact on the management of a variety of cardiovascular diseases. Pediatric patients at different age groups are exposed to a spectrum of radiation dose levels and associated cancer risks different from those of adults in diagnostic nuclear medicine procedures. Therefore, comprehensive radiation dosimetry evaluations for commonly used myocardial perfusion imaging (MPI) and viability radiotracers in target population (children and adults) at different age groups are highly desired. Methods: Using Monte Carlo calculations and biological effects of ionizing radiation VII model, we calculate the S-values for a number of radionuclides (Tl-201, Tc-99m, I-123, C-11, N-13, O-15, F-18, and Rb-82) and estimate the absorbed dose and effective dose for 12 MPI radiotracers in computational models including the newborn, 1-, 5-, 10-, 15-yr-old, and adult male and female computational phantoms. Results: For most organs, {sup 201}Tl produces the highest absorbed dose whereas {sup 82}Rb and {sup 15}O-water produce the lowest absorbed dose. For the newborn baby and adult patient, the effective dose of {sup 82}Rb is 48% and 77% lower than that of {sup 99m}Tc-tetrofosmin (rest), respectively. Conclusions: {sup 82}Rb results in lower effective dose in adults compared to {sup 99m}Tc-labeled tracers. However, this advantage is less apparent in children. The produced dosimetric databases for various radiotracers used in cardiovascular imaging, using new generation of computational models, can be used for risk-benefit assessment of a spectrum of patient population in clinical nuclear cardiology practice.

  11. Distribution of K, eU and Th and evaluation of annual radiation dose in the region of the Serra do Carambei Granite - PR; Distribuicao de K, eU e eTh e avaliacao da dose anual de radiacao na regiao do Granito Serra do Carambei - PR

    Energy Technology Data Exchange (ETDEWEB)

    Godoy, Luiz C., E-mail: luizcgodoy@brturbo.com.br [Departamento de Geociencias, Universidade Estadual de Ponta Grossa, PR (Brazil); Bittencourt, Andre V.L., E-mail: andre@ufpr.br [Laboratorio de Pesquisas Hidrogeologicas - LPH, Departamento de Geologia, Universidade Federal do Parana, Centro Politecnico, Curitiba, PR (Brazil); Santos, Leonardo J.C., E-mail: santos@ufpr.br [Laboratorio de Biogeografia e Solos - LABS, Departamento de Geografia, Universidade Federal do Parana, Centro Politecnico, Curitiba, PR (Brazil); Ferreira, Francisco J.F., E-mail: francisco.ferreira@ufpr.br [Laboratorio de Pesquisas em Geofisica Aplicada - LPGA, Departamento de Geologia, Universidade Federal do Parana, Centro Politecnico, Curitiba, PR (Brazil)

    2011-04-15

    is study was conducted in an area of 14 km in length oriented in the NNE direction by 7.3 km wide, covering the totality of the Serra do Carambei Granite and adjacent units. Located in the northern region of the Alagados dam, Parana State, this granite contains relatively high concentrations of K, eU and eTh, known since the 1970s through airborne and terrestrial gamma-ray spectrometry surveys. Recent radiochemical tests conducted on 61 samples of geological materials such as rocks (17 samples) and material of the weathering mantle and alluvial deposits (44 samples), confirmed the occurrence of radioactive anomalies in this granite, especially in thorium and uranium. The contents of K, eU and eTh obtained in gamma-ray spectrometry survey and radiochemical tests, converted to annual radiation dose (ARD), allowed to evaluate the intensity of natural radiation, whose levels relatively high in certain regions of the study area, can offer hazard to the local populations. The analysis and interpretation of data, as well the preparation of contour maps of K, eU and eTh were fundamental to understand the behavior and mobility of radionuclides in different environmental compartments of the area. (author)

  12. Radiation Dose Reduction in Paranasal Sinus CT: With Feasibility of Iterative Reconstruction Technique.

    Science.gov (United States)

    Bang, Minseo; Choi, Seong Hoon; Park, Jongha; Kang, Byeong Seong; Kwon, Woon Jung; Lee, Tae Hoon; Nam, Jung Gwon

    2016-12-01

    To (1) compare the radiation dose of low-dose computed tomography (CT) to that of standard-dose CT, (2) determine the minimum optimal radiation dose for use in patients who need endoscopic sinus surgery, and (3) assess the reliability of iterative model reconstruction. Prospective single-institution study. Tertiary care center. We recruited 48 adults with medically refractory sinusitis. Each patient underwent 4 scans with different CT parameters: 120 kV and 100 mAs (standard dose), 100 kV and 40 mAs (low dose), 100 kV and 20 mAs (very low dose), and 100 kV and 10 mAs (ultra-low dose). All CT scans were reconstructed via filtered back-projection, and ultra-low dose scans were additionally reconstructed through iterative model reconstruction. Radiation dose, image quality, and diagnostic performance were compared among the scans. Radiation doses decreased to 6% (ultra-low dose), 12% (very low dose), and 22% (low dose) of the standard-dose CT. The image quality of low-dose CT was similar to that of standard-dose CT. Ultra-low-dose CT with iterative model reconstruction was inferior to standard-dose CT for identifying anatomic structures, except for the optic nerve. All CT scans had 100% agreement for diagnosing rhinosinusitis. With low-dose CT, the radiation dose can be decreased to 22% of that of standard-dose CT without affecting the image quality. Low-dose CT can be considered the minimum optimal radiation for patients who need surgery. Iterative model reconstruction is not useful for assessing the anatomic details of the paranasal sinus on CT. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

  13. Low radiation dose to relatives after discharge of thyroid cancer patients treated with I-131

    Energy Technology Data Exchange (ETDEWEB)

    Remy, H.; Camps, E. [Pharmacy, Institut de Cancerologie Gustave Roussy, Villejuif (France); Ricard, M.; Lavielle, F.; Coulot, J. [Medical Physics, Institut de Cancerologie Gustave Roussy, Villejuif (France); Borget, I. [Health Economics, Institut de Cancerologie Gustave Roussy, Villejuif (France); Schhumberger, M. [Nuclear Medicine, Institut de Cancerologie Gustave Roussy, Villejuif (France); University Paris-sud, Bicetre (France)

    2012-07-01

    Patients treated with I-131 for thyroid carcinoma are potential source of radiation exposure for other individuals. In order to provide more reliable information to patients and relatives, this study evaluated the radiation dose received by family members after discharge from the hospital. Three main observations can be drawn. First, rhTSH (recombinant human Thyrotropin) stimulation leads to lower irradiation when mean rate is considered (cumulated irradiation divided by time contact) 1.4 {mu}Sv per hour compared to 1.6 {mu}Sv with withdrawal. However, this had no impact on the radiation dose received by relatives, because of a longer time spent close to the patient when rhTSH is used. Secondly, the mean cumulated radiation dose delivered to the relatives during the 7 days following discharge was similar with either rhTSH (58 {mu}Sv) or withdrawal patients (49.6 {mu}Sv). Thirdly, in euthyroid patients after rhTSH, the whole body retention of I-131 after three days of hospitalization is significantly lower than in hypothyroid patients after withdrawal. The hospital stay can be shortened when rhTSH is used

  14. Utilization of radiation protection gear for absorbed dose reduction: an integrative literature review

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Flavio Augusto Penna; Flor, Rita de Cassia [Instituto Federal de Santa Catarina (IFSC), Florianopolis, SC (Brazil); Pereira, Aline Garcia, E-mail: aalinegp@gmail.co [Sinan Project - Sistema de Informacao de Agravos de Notificacao, Florianopolis, SC (Brazil)

    2011-03-15

    Objective: The present study was aimed at evaluating the relation between the use of radiation protection gear and the decrease in absorbed dose of ionizing radiation, thereby reinforcing the efficacy of its use by both the patients and occupationally exposed personnel. Materials and Methods: The integrative literature review method was utilized to analyze 21 articles, 2 books, 1 thesis, 1 monograph, 1 computer program, 4 pieces of database research (Instituto Brasileiro de Geografia e Estatistica and Departamento de Informatica do Sistema Unico de Saude) and 2 sets of radiological protection guidelines. Results: Theoretically, a reduction of 86% to 99% in the absorbed dose is observed with the use of radiation protection gear. In practice, however, the reduction may achieve 88% in patients submitted to conventional radiology, and 95% in patients submitted to computed tomography. In occupationally exposed individuals, the reduction is around 90% during cardiac catheterization, and 75% during orthopedic surgery. Conclusion: According to findings of several previous pieces of research, the use of radiation protection gear is a low-cost and effective way to reduce absorbed dose both for patients and occupationally exposed individuals. Thus, its use is necessary for the implementation of effective radioprotection programs in radiodiagnosis centers. (author)

  15. Activation of chemical biological defense mechanisms and remission of vital oxidative injury by low dose radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaoka, K. [Okayama University Medical School, Okayama (Japan); Nomura, T. [Central Research Institute of Electric Power Industry, Tokyo (Japan); Kojima, S. [Science University of Tokyo, Chiba (Japan)

    2000-05-01

    still be evaluated. Hence, we studied the effect of low-dose X-ray irradiation on the synthesis of glutathione peroxidase (GSHP{sub x}), which is an antioxidant that catalyzes this reaction. The results suggest that H{sub 2}O{sub 2} produced by increased SOD activity can be detoxicated into H{sub 2}O and O{sub 2} due to simultaneous enhancement of the GSHP{sub x} activity by X-ray irradiation at 20 cGy, in contrast to irradiation at 400 cGy. The results also show the enhancement in enzyme activities by induction of their synthesis shortly after irradiation at 20 cGy. Moreover, as this phenomenon was observed in BALB/c mice (which are more radiation sensitive compared to other mouse strains) and radiation-resistant C57BL/6NJcl mice, it was considered to be a common phenomenon in the rat spleen. Remission of vital oxidative injury by low dose radiation: (1) We studied the effects of a single post whole-body low-dose radiation (50 cGy of {gamma}-ray) on mice with ferric nitrilotriacetate (Fe{sup 3+} - NTA)-induced transient hepatopathy. As a result, low-dose radiation accelerated the rate of recovery. Based on the changes in glutamic oxaloacetic transaminase activities, glutamic pyruvic transaminase activities and liquid peroxide levels, it was shown that hepatopathy improved by low dose radiation 3 hours after Fe{sup 3+} - NTA administration. This may be because of the enhancement of antioxidant agents such as total glutathione (GSH+GSSG), glutathione peroxidase, glutathione reductase and {gamma}-glutamylcysteine synthetase by low-dose radiation. These findings suggest that low-dose radiation relieved functional disorder at least in the livers of mice with active oxygen species related diseases. (2) Indications for treatment at the Misasa Hot Spring, a radon producing radioactive spring, include hypertension, diabetes mellitus and pain. To clarify its mechanisms of action on these conditions, we evaluated dynamic changes in blood components such as vasoactive substances

  16. Worldwide forecast of the biologically effective UV radiation: UV index and daily dose

    Science.gov (United States)

    Schmalwieser, Alois W.; Schauberger, Guenther; Janouch, Michal; Nunez, Manuel; Koskela, Tapani; Berger, Daniel; Karamanian, Gabriel; Prosek, Pavel; Laska, Kamil

    2002-01-01

    Since October 1995 a global daily forecast of the UV index and the daily dose, as the irradiance of the biologically effective ultraviolet radiation, for clear sky is calculated. The Austrian model as well as the input parameters are described. By connecting the daily dose with the sensitivity of the photobiological skin types, a recommendation is given to select an appropriate sun protection factor of a sunscreen to avoid overexposure of the skin. The validation of the Austrian forecast model is done by long-term measurements of the biologically effective ultraviolet radiation. Measurements were taken from 6 different sites at 4 continents (Antarctica, Australia, America and Europe) covering the latitudinal range from 67 degree(s)N to 60 degree(s)S. By using the underestimation as criteria in the sense of radiation protection, the Austrian model shows less than 12% underestimation over the whole period for the UV index and less than 10% for the daily dose. The evaluation shows further that the forecast of the daily dose is much more influenced by the attenuation due to clouds than the UV index.

  17. A dosimetric evaluation of volumetric modulated arc therapy, intensity modulated radiation therapy, and three-dimensional conformal radiation therapy for the lower extremity soft tissue sarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sol Min; Song, Seong Chan; Hyun, Sung Eun; Park, Heung Deuk; Lee, Jaegi; Kim, Young Suk; Kim, Gwi Eon [Dept. of Radiation Oncology, Jeju National University Hospital, Jeju (Korea, Republic of)

    2016-06-15

    A dosimetric evaluation of volumetric modulated arc therapy, intensity modulated radiation therapy, and three-dimensional conformal radiation therapy for the lower extremity soft tissue sarcoma For the lower extremity soft tissue sarcoma, volumetric modulated arc therapy, intensity modulated radiation therapy, and three-dimensional conformal radiation therapy were evaluated to compare these three treatment planning technique. The mean doses to the planning target volume and the femur were calculated to evaluate target coverage and the risk of bone fracture during radiation therapy. Volumetric modulated arc therapy can reduce the dose to the femur without compromising target coverage and reduce the treatment time compared with intensity modulated radiation therapy.

  18. Reproducibility of coronary plaque detection and characterization using low radiation dose coronary computed tomographic angiography in patients with intermediate likelihood of coronary artery disease (ReSCAN study)

    DEFF Research Database (Denmark)

    Ovrehus, Kristian Altern; Marwan, Mohamed; Bøtker, Hans Erik

    2012-01-01

    The purpose of this study is to evaluate the interscan, interobserver and intraobserver agreement for coronary plaque detection, and characterization using low radiation dose high-pitch spiral acquisition coronary CT angiography (CTA). Two experienced observers independently evaluated coronary CT...

  19. Low Dose Radiation Overcomes Diabetes-induced Suppression of Hippocampal Neuronal Cell Proliferation in Rats

    Science.gov (United States)

    Kim, Sang-Ki; Hong, Seong-Eon; Lee, Taeck-Hyun; Kim, Chang-Ju

    2006-01-01

    We investigated the effect of low dose radiation on diabetes induced suppression of neurogenesis in the hippocampal dentate gyrus of rat. After 0.01 Gy, 0.1 Gy, 1 Gy and 10 Gy radiation was delivered, the dentate gyrus of hippocampus of streptozotocin (STZ)-induced diabetic rats were evaluated using immunohistochemistry for 5-bromo-2-deoxyuridine (BrdU), caspase-3, and terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL) staining. The number of BrdU positive cells in the non-diabetic rats, diabetic rats without radiation, diabetic rats with 0.01 Gy radiation, diabetic rats with 0.1 Gy radiation, diabetic rats with 1 Gy radiation and diabetic rats with 10 Gy radiation were 55.4±8.5/mm2, 33.3±6.4/mm2, 67.7±10.5/mm2, 66.6±10.0/mm2, 23.5±6.3/mm2and 14.3±7.2/mm2, respectively. The number of caspase-3 positive cells was 132.6±37.4/mm2, 378.6±99.1/mm2, 15.0±2.8/mm2, 57.1±16.9/mm2, 191.8±44.8/mm2and 450.4±58.3/mm2, respectively. The number of TUNEL-positive cells was 24.5±2.0/mm2, 21.7±4.0/mm2, 20.4±2.0/mm2, 18.96±2.1/mm2, 58.3±7.9/mm2, and 106.0±9.8/mm2, respectively. These results suggest low doses of radiation paradoxically improved diabetes induced neuronal cell suppression in the hippocampal dentate gyrus of rat. PMID:16778397

  20. Model-based Iterative Reconstruction: Effect on Patient Radiation Dose and Image Quality in Pediatric Body CT

    Science.gov (United States)

    Dillman, Jonathan R.; Goodsitt, Mitchell M.; Christodoulou, Emmanuel G.; Keshavarzi, Nahid; Strouse, Peter J.

    2014-01-01

    Purpose To retrospectively compare image quality and radiation dose between a reduced-dose computed tomographic (CT) protocol that uses model-based iterative reconstruction (MBIR) and a standard-dose CT protocol that uses 30% adaptive statistical iterative reconstruction (ASIR) with filtered back projection. Materials and Methods Institutional review board approval was obtained. Clinical CT images of the chest, abdomen, and pelvis obtained with a reduced-dose protocol were identified. Images were reconstructed with two algorithms: MBIR and 100% ASIR. All subjects had undergone standard-dose CT within the prior year, and the images were reconstructed with 30% ASIR. Reduced- and standard-dose images were evaluated objectively and subjectively. Reduced-dose images were evaluated for lesion detectability. Spatial resolution was assessed in a phantom. Radiation dose was estimated by using volumetric CT dose index (CTDIvol) and calculated size-specific dose estimates (SSDE). A combination of descriptive statistics, analysis of variance, and t tests was used for statistical analysis. Results In the 25 patients who underwent the reduced-dose protocol, mean decrease in CTDIvol was 46% (range, 19%–65%) and mean decrease in SSDE was 44% (range, 19%–64%). Reduced-dose MBIR images had less noise (P > .004). Spatial resolution was superior for reduced-dose MBIR images. Reduced-dose MBIR images were equivalent to standard-dose images for lungs and soft tissues (P > .05) but were inferior for bones (P = .004). Reduced-dose 100% ASIR images were inferior for soft tissues (P ASIR. Conclusion CT performed with a reduced-dose protocol and MBIR is feasible in the pediatric population, and it maintains diagnostic quality. © RSNA, 2013 Online supplemental material is available for this article. PMID:24091359

  1. Dose-Response Relationship between Radiation Dose and Loco-regional Control in Patients with Stage II-III Esophageal Cancer Treated with Definitive Chemoradiotherapy.

    Science.gov (United States)

    Kim, Hyun Ju; Suh, Yang-Gun; Lee, Yong Chan; Lee, Sang Kil; Shin, Sung Kwan; Cho, Byung Chul; Lee, Chang Geol

    2017-07-01

    The correlation between radiation dose and loco-regional control (LRC) was evaluated in patients with stage II-III esophageal cancer treated with definitive concurrent chemoradiotherapy (CRT). Medical records of 236 stage II-III esophageal cancer patients treated with definitive CRT at Yonsei Cancer Center between 1994 and 2013 were retrospectively reviewed. Among these, 120 received a radiation dose of 60 Gy) is associated with increased LRC, PFS, and OS in patients with stage II-III esophageal cancer treated with definitive CRT.

  2. Dose-painted intensity modulated radiation therapy improves local control for locally advanced pancreas cancer.

    Science.gov (United States)

    Tunceroglu, Ahmet; Park, Joo Han; Balasubramanian, Sairam; Poppe, Matthew; Anker, Christopher J; Poplin, Elizabeth; Moss, Rebecca A; Yue, Ning J; Carpizo, Darren; Gannon, Christopher J; Haffty, Bruce G; Jabbour, Salma K

    2012-01-01

    Background. To evaluate the outcomes, adverse events, and therapeutic role of Dose-Painted Intensity-Modulated Radiation Therapy (DP-IMRT) for locally advanced pancreas cancer (LAPC). Methods. Patients with LAPC were treated with induction chemotherapy (n = 25) and those without metastasis (n = 20) received DP-IMRT consisting of 45 Gy to Planning Treatment Volume 1 (PTV1) including regional lymph nodes with a concomitant boost to the PTV2 (gross tumor volume + 0.5 cm) to either 50.4 Gy (n = 9) or 54 Gy (n = 11) in 25 fractions. DP-IMRT cases were compared to three-dimensional conformal radiation therapy (3D-CRT) plans to assess the potential relationship of radiation dose to adverse events. Kaplan-Meier and Cox regression analyses were used to calculate survival probabilities. The Fisher exact test and t-test were utilized to investigate potential prognostic factors of toxicity and survival. Results. Median overall and progression-free survivals were 11.6 and 5.9 months, respectively. Local control was 90%. Post-RT CA-19-9 levels following RT were predictive of survival (P = 0.02). Grade 2 and ≥grade 3 GI toxicity were 60% and 20%, respectively. In comparison to 3D-CRT, DP-IMRT plans demonstrated significantly lower V45 values of small bowel (P = 0.0002), stomach (P = 0.007), and mean liver doses (P = 0.001). Conclusions. Dose-escalated DP-IMRT offers improved local control in patients treated with induction chemotherapy for LAPC. Radiation-related morbidity appears reduced with DP-IMRT compared to 3D-CRT techniques, likely due to reduction in RT doses to organs at risk.

  3. Influence of Residual Tumor Volume and Radiation Dose Coverage in Outcomes for Clival Chordoma

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Mark W., E-mail: markmcdonaldmd@gmail.com [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana (United States); Indiana University Health Proton Therapy Center, Bloomington, Indiana (United States); Linton, Okechukwu R. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana (United States); Moore, Michael G.; Ting, Jonathan Y. [Department of Otolaryngology, Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, Indiana (United States); Cohen-Gadol, Aaron A.; Shah, Mitesh V. [Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana (United States); Goodman Campbell Brain and Spine, Indianapolis, Indiana (United States)

    2016-05-01

    Purpose: The purpose of this study was to evaluate factors associated with tumor control in clival chordomas. Methods and Materials: A retrospective review of 39 patients treated with surgery and proton therapy for clival chordomas between 2004 and 2014 was performed. The median prescribed dose was 77.4 Gy (relative biological effectiveness [RBE]); range was 70.2-79.2 Gy (RBE). Minimum and median doses to gross tumor volume (GTV), radiation dose received by 1 cm{sup 3} of GTV (D1cm{sup 3}), and the equivalent uniform dose were calculated. Receiver operating characteristics curves evaluated the predictive sensitivity and specificity for local failure of potential cutpoint values for GTV and D1cm{sup 3}. Results: After a median follow-up of 51 months, the 5-year estimate of local control (LC) was 69.6% (95% confidence interval [CI] 50.0%-89.2%), and overall survival (OS) was 81.4% (95% CI: 65.3%-97.5%). Tumor histology, GTV at the time of radiation, and prescribed radiation dose were significantly associated with local control on multivariate analysis, whereas D1cm{sup 3} was associated with overall survival. Compared to those patients whose conditions remained controlled, patients experiencing tumor failure had statistically significant larger GTVs and lower D1cm{sup 3}, and prescribed and median doses to GTV. A subset of 21 patients with GTV of ≤20 cm{sup 3} and D1cm{sup 3} of >67 Gy (RBE) had a median follow-up of 47 months. The 5-year estimate of local control in this subset was 81.1% (95% CI: 61.7%-100%; P=.004, overall comparison by GTV ≤20 cm{sup 3} stratified by D1cm{sup 3}). A D1cm{sup 3} of 74.5 Gy (RBE) had 80% sensitivity for local control and 60% specificity, whereas a GTV of 9.3 cm{sup 3} had 80% sensitivity for local control and 66.7% specificity. Conclusions: Local control of clival chordomas was associated with both smaller size of residual tumor and more complete high-dose coverage of residual tumor. Multidisciplinary care should seek

  4. Estimate on external effective doses received by the Iranian population from environmental gamma radiation sources

    Energy Technology Data Exchange (ETDEWEB)

    Roozitalab, J.; Reza deevband, M.; Rastkhah, N. [National Radiation Protection Dept. Atomic Energy Organization (Iran, Islamic Republic of); Sohrabi, M. [Intenatinal atomic Energy Agency, Vienna (Austria)

    2006-07-01

    Concentration of natural radioactive materials, especially available U 238, Ra 226, Th 232, and K 40 in construction materials and soil, as well as absorb dose from cosmic rays, is the most important source of the people for effective doses from the environment radiation. In order to evaluate external effective dose, it has been carried out more than 1000 measurements in 36 cities by sensitive dosimeters to environmental gamma radiation for indoor and outdoor conditions in residential areas; which its results show that range of gamma exposure for inside of buildings in Iran is 8.7-20.5 {mu}R/h, and outdoor environments of different cities is 7.9-20.6 {mu}R/h, which their mean value are 14.33 and 12.62 {mu}R/h respectively. Meanwhile, it has been estimated that beam-absorbing ratio between indoor and outdoor in measured environments is 1.55, except contribution of cosmic rays. This studies show that average effective dose for each Iranian person from environmental gamma is 96.9 n Sv/h, and annually effective dose for every person is 0.848 mSv. (authors)

  5. Cost and effectiveness of decontamination strategies in radiation contaminated areas in Fukushima in regard to external radiation dose.

    Science.gov (United States)

    Yasutaka, Tetsuo; Naito, Wataru; Nakanishi, Junko

    2013-01-01

    The objective of the present study is to evaluate the cost and effectiveness of decontamination strategies in the special decontamination areas in Fukushima in regard to external radiation dose. A geographical information system (GIS) was used to relate the predicted external dose in the affected areas to the number of potential inhabitants and the land use in the areas. A comprehensive review of the costs of various decontamination methods was conducted as part of the analysis. The results indicate that aerial decontamination in the special decontamination areas in Fukushima would be effective for reducing the air dose rate to the target level in a short period of time in some but not all of the areas. In a standard scenario, analysis of cost and effectiveness suggests that decontamination costs for agricultural areas account for approximately 80% of the total decontamination cost, of which approximately 60% is associated with storage. In addition, the costs of decontamination per person per unit area are estimated to vary greatly. Appropriate selection of decontamination methods may significantly decrease decontamination costs, allowing more meaningful decontamination in terms of the limited budget. Our analysis can help in examining the prioritization of decontamination areas from the viewpoints of cost and effectiveness in reducing the external dose. Decontamination strategies should be determined according to air dose rates and future land-use plans.

  6. Assessment of population external irradiation doses with consideration of Rospotrebnadzor bodies equipment for monitoring of photon radiation dose

    Directory of Open Access Journals (Sweden)

    I. P. Stamat

    2016-01-01

    Full Text Available This paper provides review of equipment and methodology for measurement of photon radiation dose; analysis of possible reasons for considerable deviation between the Russian Federation population annual effective external irradiation doses and the relevant average global value. Data on Rospotrebnadzor bodies dosimetry equipment used for measurement of gamma radiation dose are collected and systematized. Over 60 kinds of dosimeters are used for monitoring of population external irradiation doses. Most of dosimeters used in the country have gas-discharge detectors (Geiger-Mueller counters, minor biochemical annunciators, etc. which have higher total values of own background level and of space radiation response than the modern dosimeters with scintillation detectors. This feature of dosimeters is apparently one of most plausible reasons of a bit overstating assessment of population external irradiation doses. The options for specification of population external irradiation doses assessment are: correction of gamma radiation dose measurement results with consideration of dosimeters own background level and space radiation response, introduction of more up-to-date dosimeters with scintillation detectors, etc. The most promising direction of research in verification of population external irradiation doses assessment is account of dosimetry equipment.

  7. Influence of Dose Rate on the Cellular Response to Low- and High-LET Radiations.

    Science.gov (United States)

    Wozny, Anne-Sophie; Alphonse, Gersende; Battiston-Montagne, Priscillia; Simonet, Stéphanie; Poncet, Delphine; Testa, Etienne; Guy, Jean-Baptiste; Rancoule, Chloé; Magné, Nicolas; Beuve, Michael; Rodriguez-Lafrasse, Claire

    2016-01-01

    Nowadays, head and neck squamous cell carcinoma (HNSCC) treatment failure is mostly explained by locoregional progression or intrinsic radioresistance. Radiotherapy (RT) has recently evolved with the emergence of heavy ion radiations or new fractionation schemes of photon therapy, which modify the dose rate of treatment delivery. The aim of the present study was then to evaluate the in vitro influence of a dose rate variation during conventional RT or carbon ion hadrontherapy treatment in order to improve the therapeutic care of patient. In this regard, two HNSCC cell lines were irradiated with photons or 72 MeV/n carbon ions at a dose rate of 0.5, 2, or 10 Gy/min. For both radiosensitive and radioresistant cells, the change in dose rate significantly affected cell survival in response to photon exposure. This variation of radiosensitivity was associated with the number of initial and residual DNA double-strand breaks (DSBs). By contrast, the dose rate change did not affect neither cell survival nor the residual DNA DSBs after carbon ion irradiation. As a result, the relative biological efficiency at 10% survival increased when the dose rate decreased. In conclusion, in the RT treatment of HNSCC, it is advised to remain very careful when modifying the classical schemes toward altered fractionation. At the opposite, as the dose rate does not seem to have any effects after carbon ion exposure, there is less need to adapt hadrontherapy treatment planning during active system irradiation.

  8. The Inhibitory Effects of Low-Dose Ionizing Radiation in IgE-Mediated Allergic Responses.

    Directory of Open Access Journals (Sweden)

    Hae Mi Joo

    Full Text Available Ionizing radiation has different biological effects according to dose and dose rate. In particular, the biological effect of low-dose radiation is unclear. Low-dose whole-body gamma irradiation activates immune responses in several ways. However, the effects and mechanism of low-dose radiation on allergic responses remain poorly understood. Previously, we reported that low-dose ionizing radiation inhibits mediator release in IgE-mediated RBL-2H3 mast cell activation. In this study, to have any physiological relevance, we investigated whether low-dose radiation inhibits allergic responses in activated human mast cells (HMC-1(5C6 and LAD2 cells, mouse models of passive cutaneous anaphylaxis and the late-phase cutaneous response. High-dose radiation induced cell death, but low-dose ionizing radiation of <0.5 Gy did not induce mast cell death. Low-dose ionizing radiation that did not induce cell death significantly suppressed mediator release from human mast cells (HMC-1(5C6 and LAD2 cells that were activated by antigen-antibody reaction. To determine the inhibitory mechanism of mediator released by low-dose ionizing radiation, we examined the phosphorylation of intracellular signaling molecules such as Lyn, Syk, phospholipase Cγ, and protein kinase C, as well as the intracellular free Ca2+ concentration ([Ca2+]i. The phosphorylation of signaling molecules and [Ca2+]i following stimulation of FcεRI receptors was inhibited by low dose ionizing radiation. In agreement with its in vitro effect, ionizing radiation also significantly inhibited inflammatory cells infiltration, cytokine mRNA expression (TNF-α, IL-4, IL-13, and symptoms of passive cutaneous anaphylaxis reaction and the late-phase cutaneous response in anti-dinitrophenyl IgE-sensitized mice. These results indicate that ionizing radiation inhibits both mast cell-mediated immediate- and delayed-type allergic reactions in vivo and in vitro.

  9. Proteomic Analysis of Low Dose Arsenic and Ionizing Radiation Exposure on Keratinocytes

    OpenAIRE

    Berglund, Susanne R.; Santana, Alison R.; Li, Dan; Rice, Robert H.; Rocke, David M; Goldberg, Zelanna

    2009-01-01

    Human exposure to arsenic and ionizing radiation occur environmentally at low levels. While the human health effects of arsenic and ionizing radiation have been examined separately, there is little information regarding their combined effects at doses approaching environmental levels. Arsenic toxicity may be affected by concurrent ionizing radiation especially given their known individual carcinogenic actions at higher doses. We found that keratinocytes responded to either low dose arsenic an...

  10. Didactic revision of the operative magnitudes system ICRU for the evaluation of the equivalent dose in radiation external fields; Revision didactica del sistema de magnitudes operativas ICRU para la evaluacion de la dosis equivalente en campos externos de radiacion

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J. T., E-mail: trinidad.alvarez@inin.gob.mx [ININ, Departamento de Metrologia de Radiaciones Ionizantes, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2014-10-15

    In this work is presented in a didactic way the operative magnitudes system ICRU, showing as these magnitudes carry out an appropriate estimate of the effective equivalent doses H{sub E} and the effective dose. The objective is to present the basic concepts of the dosimetry for radiation external fields with purposes of radiological protection, because the assimilation lack and technological development of this dosimetric magnitudes system has persisted for near 50 years, in terms of practice of the radiological protection in Mexico. Also, this system is an essential part of safety basic standards of the IAEA and ICRP recommendations 26, 60, 74 and 103, as well as of the ICRU 25, 39, 43, 51 and 57. (Author)

  11. A method to obtain the same levels of CT image noise for patients of various sizes, to minimize radiation dose.

    Science.gov (United States)

    Starck, G; Lönn, L; Cederblad, A; Forssell-Aronsson, E; Sjöström, L; Alpsten, M

    2002-02-01

    The aim of this study was to develop a method of obtaining the same levels of CT image noise for patients of various sizes to minimize radiation dose. Two CT systems were evaluated regarding noise characteristics using phantoms and dosimetric measurements. Both CT systems performed well at dose levels used in normal clinical imaging, but only one was found to be suitable for low radiation dose applications. The CT system with the lowest noise level was used for further detailed studies. A simple strategy for manual selection of patient-specific scan parameters, considering patient size and required image quality, was implemented and verified on 11 volunteers. Images were obtained with at least the prescribed image quality at significantly reduced radiation dose levels compared with standard scan parameters. Depending on the diameter of the tomographic section, i.e. size of the subject, the dose levels could be reduced to 1-45% of the radiation dose with standard scan parameters (120 kV, 250 mAs, 10 mm). The results indicate a general potential for dose reduction in CT for slim patients. For tissue volume determination, large dose reductions can be achieved by adjusting the scan parameters for each individual. The concept of patient-specific scan parameters could be fully automated in the CT system design, but would require the scan to be specified in terms of image quality rather than X-ray tube load.

  12. Determining and managing fetal radiation dose from diagnostic radiology procedures in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Ozbayrak, Mustafa; Cavdar, Iffet; Seven, Mehmet; Uslu, Lebriz; Yeyin, Nami; Tanyildizi, Handan; Abuqbeitah, Mohammad; Acikgoz, A. Serdar; Tuten, Abdullah; Demir, Mustafa [Istanbul University, Istanbul (Turkmenistan)

    2015-12-15

    We intended to calculate approximate fetal doses in pregnant women who underwent diagnostic radiology procedures and to evaluate the safety of their pregnancies. We contacted hospitals in different cities in Turkey where requests for fetal dose calculation are usually sent. Fetal radiation exposure was calculated for 304 cases in 218 pregnant women with gestational ages ranging from 5 days to 19 weeks, 2 days. FetDose software (ver. 4.0) was used in fetal dose calculations for radiographic and computed tomography (CT) procedures. The body was divided into three zones according to distance from the fetus. The first zone consisted of the head area, the lower extremities below the knee, and the upper extremities; the second consisted of the cervicothoracic region and upper thighs; and the third consisted of the abdominopelvic area. Fetal doses from radiologic procedures between zones were compared using the Kruskal-Wallis test and a Bonferroni-corrected Mann-Whitney U-test. The average fetal doses from radiography and CT in the first zone were 0.05 ± 0.01 mGy and 0.81 ± 0.04 mGy, respectively; 0.21 ± 0.05 mGy and 1.77 ± 0.22 mGy, respectively, in the second zone; and 6.42 ± 0.82 mGy and 22.94 ± 1.28 mGy, respectively, in the third zone (p < 0.001). Our results showed that fetal radiation exposures in our group of pregnant women did not reach the level (50 mGy) that is known to increase risk for congenital anomalies. Fetal radiation exposure in the diagnostic radiology procedures in our study did not reach risk levels that might have indicated abortion.

  13. Radiation dose saving through the use of cone-beam CT in hearing-impaired patients.

    Science.gov (United States)

    Faccioli, N; Barillari, M; Guariglia, S; Zivelonghi, E; Rizzotti, A; Cerini, R; Mucelli, R Pozzi

    2009-12-01

    Bionic ear implants provide a solution for deafness. Patients treated with these hearing devices are often children who require close follow-up with frequent functional and radiological examinations; in particular, multislice computed tomography (MSCT). Dental volumetric cone-beam CT (CBCT) has been reported as a reliable technique for acquiring images of the temporal bone while delivering low radiation doses and containing costs. The aim of this study was to assess, in terms of radiation dose and image quality, the possibility of using CBCT as an alternative to MSCT in patients with bionic ear implants. One hundred patients (mean age 26 years, range 7-43) with Vibrant SoundBridge implants on the round window underwent follow-up: 85 with CBCT and 15 with MSCT. We measured the average tissue-absorbed doses during both MSCT and CBCT scans. Each scan was focused on the temporal bone with the smallest field of view and a low-dose protocol. In order to estimate image quality, we obtained data about slice thickness, high- and low-contrast resolution, uniformity and noise by using an AAPM CT performance phantom. Although the CBCT images were qualitatively inferior to those of MSCT, they were sufficiently diagnostic to allow evaluation of the position of the implants. The effective dose of MSCT was almost three times higher than that of CBCT. Owing to low radiation dose and sufficient image quality, CBCT could be considered an adequate technique for postoperative imaging and follow-up of patients with bionic ear implants.

  14. Radiation Sialadenitis Induced by High-dose Radioactive Iodine Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Shin Young; Lee, Jaetae [Kyungpook National University Hospital, Daegu (Korea, Republic of)

    2010-06-15

    Radioactive iodine ({sup 131}I) is accumulated in the thyroid tissue and plays an important role in the treatment of differentiated papillary and follicular cancers after thyroidectomy. Simultaneously, {sup 131}I is concentrated in the salivary glands and secreted into the saliva. Dose-related damage to the salivary parenchyma results from the {sup 131}I irradiation. Salivary gland swelling and pain, usually involving the parotid, can be seen. The symptoms may develop immediately after a therapeutic dose of {sup 131}I and/or months later and progress in intensity with time. In conjunction with the radiation sialadenitis, secondary complications reported include xerostomia, taste alterations, infection, increases in caries, facial nerve involvement, candidiasis, and neoplasia. Prevention of {sup 131}I sialadenitis may involve the use of sialogogic agents to hasten the transit time of the radioactive iodine through the salivary glands. However, studies are not available to delineate the efficacy of this approach. Treatment of the varied complications that may develop encompass numerous approaches and include gland massage, sialogogic agents, duct probing, antibiotics, mouthwashes, good oral hygiene, and adequate hydration. Recently interventional sialoendoscopy has been introduced an effective tool for the management of patients with {sup 131}I-induced sialadenitis that is unresponsive to medical treatment.

  15. [Effects of high-strip density anti-scatter grid on image quality and radiation dose].

    Science.gov (United States)

    Wamser, G; Maier, W; Aichinger, H; Bohndorf, K

    1997-06-01

    Using a new type of a stationary high strip density grid (13/75) for plain films of the abdomen, the effect was evaluated with regard to quality and patient dose in comparison with an established moving radiographic grid (12/40). The high strip density grid (13/75) was compared with a 12/40 grid using test objects and 100 patients per each grid type for plain films of the abdomen. The examinations were carried out via the screen-film system, speed class (SC) 400. Patients' weight, age and dose measurements were recorded. The image quality was evaluated via a multi-reader study using delineation of anatomical structures and a rating scale (score 1-5 or 1-3). Both measurements with test objects and patients abdominal plain films showed a decrease in radiation dose of 17% using the 13/75 grid, and 24%, respectively. The delineation of 4 out of 7 anatomical structures was slightly reduced with the new high strip density grid (maximum score reduction: 0.4), the image contrast, as well as the radiologists' subjective rating. Apart from an acceptable loss in image quality compared with the 12/40 grid, the new high strip density grid (13/ 75) enables a clear reduction in radiation dose.

  16. CT Radiation Dose Management: A Comprehensive Optimization Process for Improving Patient Safety.

    Science.gov (United States)

    Parakh, Anushri; Kortesniemi, Mika; Schindera, Sebastian T

    2016-09-01

    Rising concerns of radiation exposure from computed tomography have caused various advances in dose reduction technologies. While proper justification and optimization of scans has been the main focus to address increasing doses, the value of dose management has been largely overlooked. The purpose of this article is to explain the importance of dose management, provide an overview of the available options for dose tracking, and discuss the importance of a dedicated dose team. The authors also describe how a digital radiation tracking software can be used for analyzing the big data on doses for auditing patient safety, scanner utilization, and productivity, all of which have enormous personal and institutional implications. (©) RSNA, 2016.

  17. Magnitude of radiation doses received during diagnostic exposure in medical practice;Ordre de grandeur des doses recues lors des expositions diagnostiques en pratique medicale

    Energy Technology Data Exchange (ETDEWEB)

    Chateil, J.F. [CHU Bordeaux, 33 (France); Brisse, H. [Institut Curie, 75 - Paris (France)

    2009-10-15

    It is essential that every radiologist is able to appreciate the level of the dose delivered by the usual explorations. The comparison with other source of radiation is possible by the appreciation of the efficient dose that takes into account the expected biological effect. The transcription on the examination report of elements allowing to know the delivered dose is compulsory. from this data, it is possible by simple calculations to evaluate the level of delivered dose and then to know the order of magnitude of irradiation. Simple formula taking into account the anatomical area are proposed from dose.surface product (conventional radiology) and dose.length product (CT scanning). This constitutes an important element of dialogue with the patient. (N.C.)

  18. Radiation dose measurements during kilovoltage-cone beam computed tomography imaging in radiotherapy

    Directory of Open Access Journals (Sweden)

    A Sathish Kumar

    2016-01-01

    Conclusion: Radiation dose to the eye, breast, and the surface of the pelvis have been arrived at during CBCT. The doses measured on patients agreed closely with those measured on humanoid phantom and with published values.

  19. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, R.P.

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute {gamma}-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain.

  20. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Richard P. [Univ. of California, Berkeley, CA (United States)

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute γ-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain.

  1. Impact of radiation technique, radiation fraction dose, and total cisplatin dose on hearing : Retrospective analysis of 29 medulloblastoma patients.

    Science.gov (United States)

    Scobioala, Sergiu; Parfitt, Ross; Matulat, Peter; Kittel, Christopher; Ebrahimi, Fatemeh; Wolters, Heidi; Am Zehnhoff-Dinnesen, Antoinette; Eich, Hans Theodor

    2017-11-01

    To analyze the incidence and degree of sensorineural hearing loss (SNHL) resulting from different radiation techniques, fractionation dose, mean cochlear radiation dose (Dmean), and total cisplatin dose. In all, 29 children with medulloblastoma (58 ears) with subclinical pretreatment hearing thresholds participated. Radiotherapy (RT) and cisplatin had been applied sequentially according to the HIT MED Guidance. Audiological outcomes up to the latest follow-up (median 2.6 years) were compared. Bilateral high-frequency SNHL was observed in 26 patients (90%). No significant differences were found in mean hearing threshold between left and right ears at any frequency. A significantly better audiological outcome (p cisplatin dose reached above 210 mg/m2, with the highest abnormal level found 8-12 months after RT regardless of radiation technique or fraction dose. The cochlear radiation dose should be kept as low as possible in patients who receive simultaneous cisplatin-based chemotherapy. The risk of clinically relevant HL was shown when Dmean exceeds 45 Gy independent of radiation technique or radiation regime. Cisplatin ototoxicity was shown to have a dose-dependent effect on bilateral SNHL, which was more pronounced in higher frequencies.

  2. Monte Carlo study of radiation dose enhancement by gadolinium in megavoltage and high dose rate radiotherapy.

    Directory of Open Access Journals (Sweden)

    Daniel G Zhang

    Full Text Available MRI is often used in tumor localization for radiotherapy treatment planning, with gadolinium (Gd-containing materials often introduced as a contrast agent. Motexafin gadolinium is a novel radiosensitizer currently being studied in clinical trials. The nanoparticle technologies can target tumors with high concentration of high-Z materials. This Monte Carlo study is the first detailed quantitative investigation of high-Z material Gd-induced dose enhancement in megavoltage external beam photon therapy. BEAMnrc, a radiotherapy Monte Carlo simulation package, was used to calculate dose enhancement as a function of Gd concentration. Published phase space files for the TrueBeam flattening filter free (FFF and conventional flattened 6MV photon beams were used. High dose rate (HDR brachytherapy with Ir-192 source was also investigated as a reference. The energy spectra difference caused a dose enhancement difference between the two beams. Since the Ir-192 photons have lower energy yet, the photoelectric effect in the presence of Gd leads to even higher dose enhancement in HDR. At depth of 1.8 cm, the percent mean dose enhancement for the FFF beam was 0.38±0.12, 1.39±0.21, 2.51±0.34, 3.59±0.26, and 4.59±0.34 for Gd concentrations of 1, 5, 10, 15, and 20 mg/mL, respectively. The corresponding values for the flattened beam were 0.09±0.14, 0.50±0.28, 1.19±0.29, 1.68±0.39, and 2.34±0.24. For Ir-192 with direct contact, the enhanced were 0.50±0.14, 2.79±0.17, 5.49±0.12, 8.19±0.14, and 10.80±0.13. Gd-containing materials used in MRI as contrast agents can also potentially serve as radiosensitizers in radiotherapy. This study demonstrates that Gd can be used to enhance radiation dose in target volumes not only in HDR brachytherapy, but also in 6 MV FFF external beam radiotherapy, but higher than the currently used clinical concentration (>5 mg/mL would be needed.

  3. Monte Carlo study of radiation dose enhancement by gadolinium in megavoltage and high dose rate radiotherapy.

    Science.gov (United States)

    Zhang, Daniel G; Feygelman, Vladimir; Moros, Eduardo G; Latifi, Kujtim; Zhang, Geoffrey G

    2014-01-01

    MRI is often used in tumor localization for radiotherapy treatment planning, with gadolinium (Gd)-containing materials often introduced as a contrast agent. Motexafin gadolinium is a novel radiosensitizer currently being studied in clinical trials. The nanoparticle technologies can target tumors with high concentration of high-Z materials. This Monte Carlo study is the first detailed quantitative investigation of high-Z material Gd-induced dose enhancement in megavoltage external beam photon therapy. BEAMnrc, a radiotherapy Monte Carlo simulation package, was used to calculate dose enhancement as a function of Gd concentration. Published phase space files for the TrueBeam flattening filter free (FFF) and conventional flattened 6MV photon beams were used. High dose rate (HDR) brachytherapy with Ir-192 source was also investigated as a reference. The energy spectra difference caused a dose enhancement difference between the two