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Sample records for skin dose estimation

  1. Fast skin dose estimation system for interventional radiology.

    Science.gov (United States)

    Takata, Takeshi; Kotoku, Jun'ichi; Maejima, Hideyuki; Kumagai, Shinobu; Arai, Norikazu; Kobayashi, Takenori; Shiraishi, Kenshiro; Yamamoto, Masayoshi; Kondo, Hiroshi; Furui, Shigeru

    2018-03-01

    To minimise the radiation dermatitis related to interventional radiology (IR), rapid and accurate dose estimation has been sought for all procedures. We propose a technique for estimating the patient skin dose rapidly and accurately using Monte Carlo (MC) simulation with a graphical processing unit (GPU, GTX 1080; Nvidia Corp.). The skin dose distribution is simulated based on an individual patient's computed tomography (CT) dataset for fluoroscopic conditions after the CT dataset has been segmented into air, water and bone based on pixel values. The skin is assumed to be one layer at the outer surface of the body. Fluoroscopic conditions are obtained from a log file of a fluoroscopic examination. Estimating the absorbed skin dose distribution requires calibration of the dose simulated by our system. For this purpose, a linear function was used to approximate the relation between the simulated dose and the measured dose using radiophotoluminescence (RPL) glass dosimeters in a water-equivalent phantom. Differences of maximum skin dose between our system and the Particle and Heavy Ion Transport code System (PHITS) were as high as 6.1%. The relative statistical error (2 σ) for the simulated dose obtained using our system was ≤3.5%. Using a GPU, the simulation on the chest CT dataset aiming at the heart was within 3.49 s on average: the GPU is 122 times faster than a CPU (Core i7-7700K; Intel Corp.). Our system (using the GPU, the log file, and the CT dataset) estimated the skin dose more rapidly and more accurately than conventional methods.

  2. Estimating skin sensitization potency from a single dose LLNA.

    Science.gov (United States)

    Roberts, David W

    2015-04-01

    Skin sensitization is an important aspect of safety assessment. The mouse local lymph node assay (LLNA) developed in the 1990 s is an in vivo test used for skin sensitization hazard identification and characterization. More recently a reduced version of the LLNA (rLLNA) has been developed as a means of identifying, but not quantifying, sensitization hazard. The work presented here is aimed at enabling rLLNA data to be used to give quantitative potency information that can be used, inter alia, in modeling and read-across approaches to non-animal based potency estimation. A probit function has been derived enabling estimation of EC3 from a single dose. This has led to development of a modified version of the rLLNA, whereby as a general principle the SI value at 10%, or at a lower concentration if 10% is not testable, is used to calculate the EC3. This version of the rLLNA has been evaluated against a selection of chemicals for which full LLNA data are available, and has been shown to give EC3 values in good agreement with those derived from the full LLNA. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Skin dose estimation due to a contamination by a radionuclide β emitter: are doses equivalent good estimator of protection quantities?

    International Nuclear Information System (INIS)

    Bourgois, L.

    2011-01-01

    When handling radioactive β emitters, measurements in terms of personal dose equivalents H p (0.07) are used to estimate the equivalent dose limit to skin or extremities given by regulations. First of all, analytical expressions for individual dose equivalents H p (0.07) and equivalent doses to the extremities H skin are given for a point source and for contamination with a radionuclide β emitter. Second of all, operational quantities and protection quantities are compared. It is shown that in this case the operational quantities significantly overstate the protection quantities. For a skin contamination the ratio between operational quantities and protection quantities is 2 for a maximum β energy of 3 MeV and 90 for a maximum β energy of 150 keV. (author)

  4. Estimate of ovarian dose and entrance skin dose in uterine artery embolization procedures

    International Nuclear Information System (INIS)

    Silva, Marcia C.; Nasser, Felipe; Affonso, Breno B.; Araujo Junior, Raimundo T.; Zlotnik, Eduardo; Messina, Marcos L.; Baracat, Edmund C.

    2010-01-01

    The goal of this study was to estimate the ovarian dose and entrance skin dose (ESD) of patients who underwent uterine artery embolization (UAE) procedure. To achieve this, 49 UAE procedures were accompanied where the parameters of image acquisition were recorded for the calculation of the DEP from the output of the X-ray tube. The estimation of the ovarian dose was carried out by the insertion of a vaginal probe containing 3 TLD's. The obtained values were compared with the results of other authors and a higher value of ovarian dose (28,97 cGy) and ESD (403,57 cGy) was found in this work. Analysis of the results allowed to observe that this result was obtained mainly as a result of the high number of arteriography series and the frames/second rates employed. Following on from these observations, the protocol of EMUT was altered reducing the frames/seg rate from 2 to 1. Efforts with a view to reducing the number of arteriography series also became part of the next proceedings. (author)

  5. Method of estimating patient skin dose from dose displayed on medical X-ray equipment with flat panel detector

    International Nuclear Information System (INIS)

    Fukuda, Atsushi; Koshida, Kichiro; Togashi, Atsuhiko; Matsubara, Kousuke

    2004-01-01

    The International Electrotechnical Commission (IEC) has stipulated that medical X-ray equipment for interventional procedures must display radiation doses such as air kerma in free air at the interventional reference point and dose area product to establish radiation safety for patients (IEC 60601-2-43). However, it is necessary to estimate entrance skin dose for the patient from air kerma for an accurate risk assessment of radiation skin injury. To estimate entrance skin dose from displayed air kerma in free air at the interventional reference point, it is necessary to consider effective energy, the ratio of the mass-energy absorption coefficient for skin and air, and the backscatter factor. In addition, since automatic exposure control is installed in medical X-ray equipment with flat panel detectors, it is necessary to know the characteristics of control to estimate exposure dose. In order to calculate entrance skin dose under various conditions, we investigated clinical parameters such as tube voltage, tube current, pulse width, additional filter, and focal spot size, as functions of patient body size. We also measured the effective energy of X-ray exposure for the patient as a function of clinical parameter settings. We found that the conversion factor from air kerma in free air to entrance skin dose is about 1.4 for protection. (author)

  6. Measurement and estimation of maximum skin dose to the patient for different interventional procedures

    International Nuclear Information System (INIS)

    Cheng Yuxi; Liu Lantao; Wei Kedao; Yu Peng; Yan Shulin; Li Tianchang

    2005-01-01

    Objective: To determine the dose distribution and maximum skin dose to the patient for four interventional procedures: coronary angiography (CA), hepatic angiography (HA), radiofrequency ablation (RF) and cerebral angiography (CAG), and to estimate the definitive effect of radiation on skin. Methods: Skin dose was measured using LiF: Mg, Cu, P TLD chips. A total of 9 measuring points were chosen on the back of the patient with two TLDs placed at each point, for CA, HA and RF interventional procedures, whereas two TLDs were placed on one point each at the postero-anterior (PA) and lateral side (LAT) respectively, during the CAG procedure. Results: The results revealed that the maximum skin dose to the patient was 1683.91 mGy for the HA procedure with a mean value of 607.29 mGy. The maximum skin dose at the PA point was 959.3 mGy for the CAG with a mean value of 418.79 mGy; While the maximum and the mean doses at the LAT point were 704 mGy and 191.52 mGy, respectively. For the RF procedure the maximum dose was 853.82 mGy and the mean was 219.67 mGy. For the CA procedure the maximum dose was 456.1 mGy and the mean was 227.63 mGy. Conclusion: All the measured dose values in this study are estimated ones which could not provide the accurate maximum value because it is difficult to measure using a great deal of TLDs. On the other hand, the small area of skin exposed to high dose could be missed as the distribution of the dose is successive. (authors)

  7. Dosimetric Aspects of Personnel Skin Contamination by Radionuclides - Estimate of a Skin Dose, Monitoring and Interpretation of Results

    International Nuclear Information System (INIS)

    Husak, V.; Kleinbauer, K.

    2001-01-01

    Full text: On the basis of a critical comparison of literary data, tables are compiled of beta and gamma dose rate in mSvh -1 (kBqcm -1 ) to the basal layer of the skin at 0.07 mm depth from contamination by 75 radionuclides unsealed sources; radioactive substances are assumed to reside on the skin surface. The residence time needed for the estimate of the skin dose is calculated assuming that a residual activity per unit area of any radionuclide on the skin, which could not be removed by the repeated careful decontamination, is supposed to be eliminated with the biological half-life of 116 h as a consequence of the natural sloughing off of the skin. Radionuclides are divided into five groups according to the dose estimate in mSv (kBqcm -2 ): ≥250 (e.g. 32 P, 89 Sr, 137 Cs/ 137m Ba), 100-250 (e.g. 90 Y, 131 I, 186 Re), 10-100 (e.g. 35 S, 67 Ga, 200 Tl), 1-10 (e.g. 18 F, 51 Cr, 99m Tc), ≤1 (e.g. 63 Ni, 144 Pr, 238 U). If it is possible, doses can be determined more precisely by measuring the effective half-life of the residual activity on the contaminated area. Our dose estimates are approximately valid on the condition that, after decontamination, residual activity of radionuclides persists predominantly in the superficial layers of epidermis. This and further uncertainties connected with the dose assessment are discussed. Our tables can help to determine easily rough values of doses to personnel in contamination incidents and to interpret them in relation to regulatory derived limits. This work was supported by State Office for Nuclear Safety in Prague. (author)

  8. SU-F-P-44: A Direct Estimate of Peak Skin Dose for Interventional Fluoroscopy Procedures

    International Nuclear Information System (INIS)

    Weir, V; Zhang, J

    2016-01-01

    Purpose: There is an increasing demand for medical physicist to calculate peak skin dose (PSD) for interventional fluoroscopy procedures. The dose information (Dose-Area-Product and Air Kerma) displayed in the console cannot directly be used for this purpose. Our clinical experience shows that the use of the existing methods may overestimate or underestimate PSD. This study attempts to develop a direct estimate of PSD from the displayed dose metrics. Methods: An anthropomorphic torso phantom was used for dose measurements for a common fluoroscopic procedure. Entrance skin doses were measured with a Piranha solid state point detector placed on the table surface below the torso phantom. An initial “reference dose rate” (RE) measurement was conducted by comparing the displayed dose rate (mGy/min) to the dose rate measured. The distance from table top to focal spot was taken as the reference distance (RD at the RE. Table height was then adjusted. The displayed air kerma and DAP were recorded and sent to three physicists to estimate PSD. An inverse square correction was applied to correct displayed air kerma at various table heights. The PSD estimated by physicists and the PSD by the proposed method were then compared with the measurements. The estimated DAPs were compared to displayed DAP readings (mGycm2). Results: The difference between estimated PSD by the proposed method and direct measurements was less than 5%. For the same set of data, the estimated PSD by each of three physicists is different from measurements by ±52%. The DAP calculated by the proposed method and displayed DAP readings in the console is less than 20% at various table heights. Conclusion: PSD may be simply estimated from displayed air kerma or DAP if the distance between table top and tube focal spot or if x-ray beam area on table top is available.

  9. SU-F-P-44: A Direct Estimate of Peak Skin Dose for Interventional Fluoroscopy Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Weir, V [Baylor Scott and White Healthcare System, Dallas, TX (United States); Zhang, J [University of Kentucky, Lexington, KY (United States)

    2016-06-15

    Purpose: There is an increasing demand for medical physicist to calculate peak skin dose (PSD) for interventional fluoroscopy procedures. The dose information (Dose-Area-Product and Air Kerma) displayed in the console cannot directly be used for this purpose. Our clinical experience shows that the use of the existing methods may overestimate or underestimate PSD. This study attempts to develop a direct estimate of PSD from the displayed dose metrics. Methods: An anthropomorphic torso phantom was used for dose measurements for a common fluoroscopic procedure. Entrance skin doses were measured with a Piranha solid state point detector placed on the table surface below the torso phantom. An initial “reference dose rate” (RE) measurement was conducted by comparing the displayed dose rate (mGy/min) to the dose rate measured. The distance from table top to focal spot was taken as the reference distance (RD at the RE. Table height was then adjusted. The displayed air kerma and DAP were recorded and sent to three physicists to estimate PSD. An inverse square correction was applied to correct displayed air kerma at various table heights. The PSD estimated by physicists and the PSD by the proposed method were then compared with the measurements. The estimated DAPs were compared to displayed DAP readings (mGycm2). Results: The difference between estimated PSD by the proposed method and direct measurements was less than 5%. For the same set of data, the estimated PSD by each of three physicists is different from measurements by ±52%. The DAP calculated by the proposed method and displayed DAP readings in the console is less than 20% at various table heights. Conclusion: PSD may be simply estimated from displayed air kerma or DAP if the distance between table top and tube focal spot or if x-ray beam area on table top is available.

  10. Calculational methods for estimating skin dose from electrons in Co-60 gamma-ray beams

    International Nuclear Information System (INIS)

    Higgins, P.D.; Sibata, C.H.; Attix, F.H.; Paliwal, B.R.

    1983-01-01

    Several methods have been employed to calculate the relative contribution to skin dose due to scattered electrons in Co-60 gamma-ray beams. Either the Klein-Nishina differential scattering probability is employed to determine the number and initial energy of electrons scattered into the direction of a detector, or a Gaussian approximation is used to specify the surface distribution of initial pencil electron beams created by parallel or diverging photon fields. Results of these calculations are compared with experimental data. In addition, that fraction of relative surface dose resulting from photon interactions in air alone is estimated and compared with data extrapolated from measurements at large source-surface distance (SSD). The contribution to surface dose from electrons generated in air is 50% or more of the total skin dose for SSDs greater than 80 cm

  11. Calculational methods for estimating skin dose from electrons in Co-60 gamma-ray beams

    International Nuclear Information System (INIS)

    Higgins, P.D.; Sibata, C.H.; Attix, F.H.; Paliwal, B.R.

    1983-01-01

    Several methods have been employed to calculate the relative contribution to skin dose due to scattered electrons in Co-60 γ-ray beams. Either the Klein--Nishina differential scattering probability is employed to determine the number and initial energy of electrons scattered into the direction of a detector, or a Gaussian approximation is used to specify the surface distribution of initial pencil electron beams created by parallel or diverging photon fields. Results of these calculations are compared with experimental data. In addition, that fraction of relative surface dose resulting from photon interactions in air alone is estimated and compared with data extrapolated from measurements at large source--surface distance (SSD). The contribution to surface dose from electrons generated in air is 50% or more of the total skin dose for SSDs greater than 80 cm

  12. SU-F-P-47: Estimation of Skin Dose by Performing the Measurements On Cylindrical Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Bosma, S; Sanders, M; Aryal, P [University Kentucky - Chandler Medical Ctr, Lexington, KY (United States)

    2016-06-15

    Purpose: To evaluate the skin dose by performing the measurements on cylindrical phantom with 6X beam. Methods: A cylindrical phantom was used to best model a patient surface. The source to surface distance (SSD) was 100 cm at phantom surface along central axis (CAX). The EBT2 films were cut into 2×2 cm2 pieces. Each piece of film was placed at CAX on phantom surface for each measurement at 0°, 15°, 30°, 45°, 60°, 75°, and 90° gantry angles for field sizes of 5×5, 10×10, 15×15, and 20×20 cm{sup 2} respectively. One hundred monitor units (MU) with 6X beam were delivered for each set up. Similarly, the measurements were repeated using lithium fluoride (LiF) thermoluminescent dosimeter (TLD) chips (1X1X1 mm{sup 3}). Two TLD chips were placed for each gantry angle and field size. The calibration curves were produced for both film and TLD. The computed tomography (CT) was also performed on the same cylindrical phantom and dose was evaluated at the phantom surface using Eclipse treatment planning system ( AAA algorithm) for skin dose comparison. Results: Data showed small differences at smaller angles among EBT2, TLD and Eclipse treatment planning system. But Eclipse treatment planning system under estimated the skin dose between 20% and 50% at larger gantry angles (between 40° and 80°) at all field sizes before dose differences began to converge. Conclusion: Given this data, we can conclude that Eclipse treatment planning system under estimated the dose especially between 40 and 80 degrees of obliquity compared to the measurements results. Ideally, this study can be applied largely to head and neck patients where contours differ drastically and where skin dose is paramount.

  13. Rat skin carcinogenesis as a basis for estimating risks at low doses and dose rates of various types of radiation

    International Nuclear Information System (INIS)

    Burns, F.J.; Vanderlaan, M.; Strickland, P.; Albert, R.E.

    1976-01-01

    The recovery rate, age dependence and latent period for tumor induction in rat skin were measured for single and split doses of radiation, and the data were analyzed in terms of a general model in an attempt to estimate the expected tumor response for various types of radiation given at low dose rates for long periods of time. The dorsal skin of male rats was exposed to electrons, x rays, or protons in either single or split doses for several doses and the tumor responses were compared during 80 weeks of observation. A two stage model incorporating a reversible or recoverable mode was developed and various parameters in the model, including recovery rate, dose-response coefficients, and indices of age sensitivity, were evaluated experimentally. The measured parameters were then utilized to calculate expected tumor responses for exposure periods extending for duration of life. The calculations indicated that low dose rates could be markedly ( 1 / 100 to 1 / 1000 ) less effective in producing tumors than the same dose given in a short or acute exposure, although the magnitude of the reduction in effectiveness declines as the dose declines

  14. A Computer Program Method for Estimation of Entrance Skin Dose for some Individuals Undergoing X-ray Imaging

    International Nuclear Information System (INIS)

    Taha, T.M.; Allehyani, S.

    2012-01-01

    A computer program depends on practical measurements of entrance skin dose patients undergoing radiological examinations. Physical parameters such as field size, half value layer, backscatter factor, dose output, focal film distance, focal skin distance, normal operating conditions were taken into consideration for calculation entrance skin dose. It was measured by many techniques such as Thermo-luminescence dosimeters, ionization chambers. TLD technique characterized by high precision and reproducibility of dose measurement is checked by addressing pre-readout annealing, group sorting, dose evaluation, Fifty TLD chips were annealed for 1 hour at 400 degree C followed by 2 h at 100 degree C. After exposure to constant dose from X-ray generator. 0.6 cc Ionization chamber was located at surface of water chest phantom that has dimensions of 40 cm x 40 cm x 20 cm and connected with farmer dose master. Entrance Skin Dose was calculated using the generated software by changing the physical parameters and using the measured output doses. The obtained results were compared with the reference levels of International Atomic Energy Authority. The constructed computer program provides an easy and more practical mean of estimating skin dose even before exposure. They also provide the easiest and cheapest technique can be employed in any entrance skin dose measurement

  15. Comparison of measured and estimated maximum skin doses during CT fluoroscopy lung biopsies

    Energy Technology Data Exchange (ETDEWEB)

    Zanca, F., E-mail: Federica.Zanca@med.kuleuven.be [Department of Radiology, Leuven University Center of Medical Physics in Radiology, UZ Leuven, Herestraat 49, 3000 Leuven, Belgium and Imaging and Pathology Department, UZ Leuven, Herestraat 49, Box 7003 3000 Leuven (Belgium); Jacobs, A. [Department of Radiology, Leuven University Center of Medical Physics in Radiology, UZ Leuven, Herestraat 49, 3000 Leuven (Belgium); Crijns, W. [Department of Radiotherapy, UZ Leuven, Herestraat 49, 3000 Leuven (Belgium); De Wever, W. [Imaging and Pathology Department, UZ Leuven, Herestraat 49, Box 7003 3000 Leuven, Belgium and Department of Radiology, UZ Leuven, Herestraat 49, 3000 Leuven (Belgium)

    2014-07-15

    Purpose: To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. Methods: Data from 50 patients with lung lesions who underwent a CT fluoroscopy-guided biopsy were collected. The CT protocol consisted of a low-kilovoltage (80 kV) protocol used in combination with an algorithm for dose reduction to the radiology staff during the interventional procedure, HandCare (HC). MSD was assessed during each intervention using EBT2 gafchromic films positioned on patient skin. Lesion size, position, total fluoroscopy time, and patient-effective diameter were registered for each patient. Dose rates were also estimated at the surface of a normal-size anthropomorphic thorax phantom using a 10 cm pencil ionization chamber placed at every 30°, for a full rotation, with and without HC. Measured MSD was compared with MSD values estimated from the phantom measurements and with the cumulative CTDIvol of the procedure. Results: The median measured MSD was 141 mGy (range 38–410 mGy) while the median cumulative CTDIvol was 72 mGy (range 24–262 mGy). The ratio between the MSD estimated from phantom measurements and the measured MSD was 0.87 (range 0.12–4.1) on average. In 72% of cases the estimated MSD underestimated the measured MSD, while in 28% of the cases it overestimated it. The same trend was observed for the ratio of cumulative CTDIvol and measured MSD. No trend was observed as a function of patient size. Conclusions: On average, estimated MSD from dose rate measurements on phantom as well as from CTDIvol of patient examinations underestimates the measured value of MSD. This can be attributed to deviations of the patient's body habitus from the standard phantom size and to patient positioning in the gantry during the procedure.

  16. Comparison of measured and estimated maximum skin doses during CT fluoroscopy lung biopsies

    International Nuclear Information System (INIS)

    Zanca, F.; Jacobs, A.; Crijns, W.; De Wever, W.

    2014-01-01

    Purpose: To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. Methods: Data from 50 patients with lung lesions who underwent a CT fluoroscopy-guided biopsy were collected. The CT protocol consisted of a low-kilovoltage (80 kV) protocol used in combination with an algorithm for dose reduction to the radiology staff during the interventional procedure, HandCare (HC). MSD was assessed during each intervention using EBT2 gafchromic films positioned on patient skin. Lesion size, position, total fluoroscopy time, and patient-effective diameter were registered for each patient. Dose rates were also estimated at the surface of a normal-size anthropomorphic thorax phantom using a 10 cm pencil ionization chamber placed at every 30°, for a full rotation, with and without HC. Measured MSD was compared with MSD values estimated from the phantom measurements and with the cumulative CTDIvol of the procedure. Results: The median measured MSD was 141 mGy (range 38–410 mGy) while the median cumulative CTDIvol was 72 mGy (range 24–262 mGy). The ratio between the MSD estimated from phantom measurements and the measured MSD was 0.87 (range 0.12–4.1) on average. In 72% of cases the estimated MSD underestimated the measured MSD, while in 28% of the cases it overestimated it. The same trend was observed for the ratio of cumulative CTDIvol and measured MSD. No trend was observed as a function of patient size. Conclusions: On average, estimated MSD from dose rate measurements on phantom as well as from CTDIvol of patient examinations underestimates the measured value of MSD. This can be attributed to deviations of the patient's body habitus from the standard phantom size and to patient positioning in the gantry during the procedure

  17. Improvement of the equivalent sphere model for better estimates of skin or eye dose in space radiation environments

    International Nuclear Information System (INIS)

    Lin, Z.W.

    2011-01-01

    It is often useful to get a quick estimate of the dose or dose equivalent of an organ, such as blood-forming organs, the eye or the skin, in a radiation field. Sometimes an equivalent sphere is used to represent the organ for this purpose. For space radiation environments, recently it has been shown that the equivalent sphere model does not work for the eye or the skin in solar particle event environments. In this study, we improve the representation of the eye and the skin using a two-component equivalent sphere model. Motivated by the two-peak structure of the body organ shielding distribution for the eye and the skin, we use an equivalent sphere with two radius parameters, for example a partial spherical shell of a smaller thickness over a proper fraction of the full solid angle combined with a concentric partial spherical shell of a larger thickness over the rest of the full solid angle, to represent the eye or the skin. We find that using an equivalent sphere with two radius parameters instead of one drastically improves the accuracy of the estimates of dose and dose equivalent in space radiation environments. For example, in solar particle event environments the average error in the estimate of the skin dose equivalent using an equivalent sphere with two radius parameters is about 8%, while the average error of the conventional equivalent sphere model using one radius parameter is around 100%.

  18. Estimating pediatric entrance skin dose from digital radiography examination using DICOM metadata: A quality assurance tool

    Energy Technology Data Exchange (ETDEWEB)

    Brady, S. L., E-mail: samuel.brady@stjude.org; Kaufman, R. A., E-mail: robert.kaufman@stjude.org [Department of Diagnostic Imaging, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105 (United States)

    2015-05-15

    Purpose: To develop an automated methodology to estimate patient examination dose in digital radiography (DR) imaging using DICOM metadata as a quality assurance (QA) tool. Methods: Patient examination and demographical information were gathered from metadata analysis of DICOM header data. The x-ray system radiation output (i.e., air KERMA) was characterized for all filter combinations used for patient examinations. Average patient thicknesses were measured for head, chest, abdomen, knees, and hands using volumetric images from CT. Backscatter factors (BSFs) were calculated from examination kVp. Patient entrance skin air KERMA (ESAK) was calculated by (1) looking up examination technique factors taken from DICOM header metadata (i.e., kVp and mA s) to derive an air KERMA (k{sub air}) value based on an x-ray characteristic radiation output curve; (2) scaling k{sub air} with a BSF value; and (3) correcting k{sub air} for patient thickness. Finally, patient entrance skin dose (ESD) was calculated by multiplying a mass–energy attenuation coefficient ratio by ESAK. Patient ESD calculations were computed for common DR examinations at our institution: dual view chest, anteroposterior (AP) abdomen, lateral (LAT) skull, dual view knee, and bone age (left hand only) examinations. Results: ESD was calculated for a total of 3794 patients; mean age was 11 ± 8 yr (range: 2 months to 55 yr). The mean ESD range was 0.19–0.42 mGy for dual view chest, 0.28–1.2 mGy for AP abdomen, 0.18–0.65 mGy for LAT view skull, 0.15–0.63 mGy for dual view knee, and 0.10–0.12 mGy for bone age (left hand) examinations. Conclusions: A methodology combining DICOM header metadata and basic x-ray tube characterization curves was demonstrated. In a regulatory era where patient dose reporting has become increasingly in demand, this methodology will allow a knowledgeable user the means to establish an automatable dose reporting program for DR and perform patient dose related QA testing for

  19. Application of work load spectra for estimative of the skin entrance dose

    International Nuclear Information System (INIS)

    Pereira, P.A.A.; Furquim, T.A.C.; Costa, P.R.

    2004-01-01

    The present work refers to obtaining data for the determination of workload spectra related to the use of different radiological equipment. The obtained information was stored in a data base developed for this working program. Values of skin entrance dose were obtained bu using the results of the field research (performed in radiological clinics and hospitals of Sao Paulo). (author)

  20. Estimation of dose in skin through the use of radiochromic and radiographic films in patients subjected to interventional procedures

    International Nuclear Information System (INIS)

    Campos Garcia, Juan Pablo

    2014-01-01

    Radiation doses in skin of patients subjected to interventional procedures is estimated from the utilization and analysis of GAFCHROMIC® XR-RV2 radiochromic films and KODAK® X-Omat films with aid of the ImageJ software. The distribution of the radiation fields in the films is generated to obtain the distribution of dose in skin and to find peaks of dose by isodose curves using ImageJ software. The calibration curves are realized from GAFCHROMIC® XR-RV2 radiochromic films, through the use of a densitometer and two types of scanners (reflection scanner and transmission scanner). The reflection scanner has digitalized color images of 48 bit in TIFF format. The scanner transmission has digitalized in grayscale images to 16 bit in TIFF format. Each method has determined the points with maximum dose in skin. The images of the areas of regions with maximum doses are obtained of the scanner. The quantified doses are compared in the radiochromic films with the band of doses supplied by the manufacturer. The methodologies for the estimation of the doses obtained are compared of the radiochromic films with those obtained with the KODAK® X-Omat films. The procedure of obtaining of the doses is validated in patients with KODAK® X-Omat films. The doses obtained have covered a range from the 0,1Gy to 9 Gy. Radiographic films have allowed an assessment of the doses to 900 cGy due to the saturation thereof, the doses found in that range have been consistent with the doses in radiochromic films [es

  1. Valorization of the GAFCHROMIC XR-R film for radiation dose estimation in the skin

    International Nuclear Information System (INIS)

    Sanchez Garcia, M.; Otero Martinez, C.; Camino, X. M.; Sendon del Rio, J. R.; Luna Vega, V.; Lobato Busto, R.; Mosquera Sueiro, J.; Pombar Camean, M.

    2006-01-01

    The adequacy of the couple formed by the GAFCHROMIC XR-R film and the MICROTEK Scan Maker 8700 for skin dose determination has been evaluated. The main advantages are the ease of use the films, since it can be manipulated without special care and the ability to archive it in the dosimetric history of the patient. The main limiting factors coming from the scanner are the reproducibility over time and noise in the digitization; it is shown that this last component can be minimized at the cost of resolution. From the film itself, the limiting factors are the inter and intra film uniformity. Contributing an 6,5% to the overall uncertainty in dose determination. Overall, it has been shown that skin dose determination is possible with this film with an uncertainty below 10%. (Author)

  2. Skin dose estimation for various beam modifiers and source-to-surface distances for 6MV photons

    Directory of Open Access Journals (Sweden)

    Yadav Girigesh

    2009-01-01

    Full Text Available The purpose of this study was to learn the skin dose estimation for various beam modifiers at various source-to-surface distances (SSDs for a 6 MV photon. Surface and buildup region doses were measured with an acrylic slab phantom and Markus 0.055 cc parallel plate (PP ionization chamber. Measurements were carried out for open fields, motorized wedge fields, acrylic block tray fields ranging from 3 x 3 cm 2 to 30 x 30 cm 2 . Twenty-five percent of the field was blocked with a cerrobend block and a Multileaf collimator (MLC. The effect of the blocks on the skin dose was measured for a 20 x 20 cm 2 field size, at 80 cm, 100 cm and 120 cm SSD. During the use of isocentric treatments, whereby the tumor is positioned at 100 cm from the source, depending on the depth of the tumor and size of the patient, the SSD can vary from 80 cm to 100 cm. To achieve a larger field size, the SSD can also be extended up to 120 cm at times. The skin dose increased as field size increased. The skin dose for the open 10 x10 cm 2 field was 15.5%, 14.8% and 15.5% at 80 cm, 100 cm and 120 cm SSDs, respectively. The skin dose due to a motorized 60 0 wedge for the 10 x 10 cm 2 field was 9.9%, 9.5%, and 9.5% at 80 cm, 100 cm and 120 cm SSDs. The skin dose due to acrylic block tray, of thickness 1.0 cm for a 10 x 10 cm 2 field was 27.0%, 17.2% and 16.1% at 80, 100 and 120 cm SSD respectively. Due to the use of an acrylic block tray, the surface dose was increased for all field sizes at the above three SSDs and the percentage skin dose was more dominant at the lower SSD and larger field size. The skin dose for a 30 x 30 cm 2 field size at 80 cm SSD was 38.3% and it was 70.4% for the open and acrylic block tray fields, respectively. The skin doses for motorized wedge fields were lower than for open fields. The effect of SSDs on the surface dose for motorized 60° wedge fields was not significant for a small field size (difference was less than 1% up to a 15 x 15 cm 2 field size

  3. Evaluation of F/E·DOI method as an approximate estimate of skin dose during percutaneous coronary intervention procedure

    International Nuclear Information System (INIS)

    Nakahara, Makoto; Yoshino, Akira; Kitano, K.; Yamaguchi, M.; Morone, Takayuki; Tani, K.

    2005-01-01

    The purpose of this study was to evaluate the efficacy of fluoroscopy time/total exposure times exposure times · in direction of interest (F/E·DOI) method as an approximate estimate of skin dose during percutaneous coronary intervention (PCI) procedure. Up to March 10, 2004, fifty-seven patients (male: 46 cases, female: 11 cases, age range 38-85 years; mean age 67±11 years) had undergone PCI and 157 directions of exposure was measured using X-ray films (KONICA MINOLTA SR-DUP) placed under the back of each patient during the procedure. The fluoroscopy time (minutes), the times of exposure in each direction during the procedure, and the thickness of chest (cm) was recorded. The relation of the skin dose to fluoroscopic time, exposure times in direction of interest, and F/E·DOI was assessed. The relationship between fluoroscopy time and skin dose was shown as y=0.02x+0.22 (r=0.54, p<0.0001, m.e=0.00±0.71 Gy, e.a=-2.19∼l.53 Gy). In addition, the relation of skin dose to exposure times in the direction of interest was y=0.07x+0.27 (r=0.77, p<0.0001, m.e=-0.00±0.53 Gy, e.a=-2.45∼1.76 Gy). The relationship between skin dose and F/E·DOI was y=0.06x+0.30 (r=0.85, p<0.0001, m.e=-0.00±0.44 Gy, e.a=-1.28∼1.06 Gy). Moreover, the relationship between skin dose and (F/E·DOI x 0.06+0.30) x coefficient of direction x coefficient in thickness of chest was y=0.99x-0.02 (r=0.89, p<0.0001, m.e=0.00±0.38 Gy, e.a=-1.12∼l.27 Gy). The calculated results corresponded to the skin dose during the procedure. F/E·DOI method was simple and effective, moreover, that enabled us to inform the skin dose during the PCI procedure to the interventionalist easily. (authors)

  4. Dose estimation at the entrance of the skin in diagnostic imaging equipment using distributions of workloads

    International Nuclear Information System (INIS)

    Pereira, Paula A.A.; Furquim, Tania A.C.; Costa, Paulo R.

    2005-01-01

    The work proposed to implement workload distributions with respect to radiological equipment of different technologies, the input dose calculation in the skin (DEP). With the results of the survey in the field (radiological clinics and hospitals of the city of Sao Paulo, SP, Brazil), a methodology was studied for the application of this information in the calculation of DEP and the application of statistical treatment of results of measurements performed. With the results, we can conclude that the choice of the appropriate number of samples is important in order to obtain statistically acceptable values. In addition, it can be concluded that the method presented is valid because the DEP found values are very close to the values calculated by other methods previously developed by the authors

  5. A model for beta skin dose estimation due to the use of a necklace with uranium depleted bullets

    International Nuclear Information System (INIS)

    Lavalle Heibron, P.H.; Pérez Guerrero, J.S.; Oliveira, J.F. de

    2015-01-01

    Depleted uranium bullets were use as munitions during the Kuwait – Iraq war and the International Atomic Energy Agency sampling expert’s team found fragments in the environment when the war was over. Consequently, there is a possibility that members of the public, especially children, collects DU fragments and use it, for example, to make a necklace. This paper estimates the beta skin dose to a child that uses a necklace made with a depleted uranium bullet. The theoretical model for dose estimation is based on Loevinguer’s equation with a correction factor adjusted for the maximum beta energy in the range between 0.1 and 2.5 MeV calculated taking into account the International Atomic Energy Agency expected doses rates in air at one meter distance of a point source of 37 GBq, function of the maximum beta energy. The dose rate estimated by this work due to the child use of a necklace with one depleted uranium bullet of 300 g was in good agreement with other results founded in literature. (authors)

  6. Reference air kerma and kerma-area product as estimators of peak skin dose for fluoroscopically guided interventions

    International Nuclear Information System (INIS)

    Kwon, Deukwoo; Little, Mark P.; Miller, Donald L.

    2011-01-01

    Purpose: To determine more accurate regression formulas for estimating peak skin dose (PSD) from reference air kerma (RAK) or kerma-area product (KAP). Methods: After grouping of the data from 21 procedures into 13 clinically similar groups, assessments were made of optimal clustering using the Bayesian information criterion to obtain the optimal linear regressions of (log-transformed) PSD vs RAK, PSD vs KAP, and PSD vs RAK and KAP. Results: Three clusters of clinical groups were optimal in regression of PSD vs RAK, seven clusters of clinical groups were optimal in regression of PSD vs KAP, and six clusters of clinical groups were optimal in regression of PSD vs RAK and KAP. Prediction of PSD using both RAK and KAP is significantly better than prediction of PSD with either RAK or KAP alone. The regression of PSD vs RAK provided better predictions of PSD than the regression of PSD vs KAP. The partial-pooling (clustered) method yields smaller mean squared errors compared with the complete-pooling method.Conclusion: PSD distributions for interventional radiology procedures are log-normal. Estimates of PSD derived from RAK and KAP jointly are most accurate, followed closely by estimates derived from RAK alone. Estimates of PSD derived from KAP alone are the least accurate. Using a stochastic search approach, it is possible to cluster together certain dissimilar types of procedures to minimize the total error sum of squares.

  7. Multilayer detector for skin absorbed dose measuring

    International Nuclear Information System (INIS)

    Osanov, D.P.; Panova, V.P.; Shaks, A.I.

    1985-01-01

    A method for skin dosimetry based on utilization of multilayer detectors and permitting to estimate distribution of absorbed dose by skin depth is described. The detector represents a set of thin sensitive elements separated by tissue-equivalent absorbers. Quantitative evaluation and forecasting the degree of radiation injury of skin are determined by the formula based on determination of the probability of the fact that cells are not destroyed and they can divide further on. The given method ensures a possibility of quantitative evaluation of radiobiological effect and forecasting clinical consequences of skin irradiation by results of corresponding measurements of dose by means of the miultilayer detector

  8. Estimation of deep, eye lens and skin doses for high energy electron beams for dosimetry and protection purpose

    International Nuclear Information System (INIS)

    Reena Kumari; Rakesh, R.B.

    2018-01-01

    In the radiological protection especially for individual as well as area monitoring, it is generally considered that beta sources deposit skin and eye lens doses only as they do not have enough energy for depositing doses at 10 mm depth. Also, the skin and eye lens doses differ substantially due to attenuation of beta particles at 0.07 mm (skin) and 3 mm (eye lens) depths and the surface doses are always greater than eye lens doses even for the highest energy beta source used in brachytherapy applications. However, worldwide increase in the use of high energy electron accelerators, new challenges are being posed for radiological protection and the operational quantities defined previously by ICRU are being reviewed. In view of these developments, studies have been performed for different electron beams in the energy range from (4 - 20) MeV generated using a medical linear accelerator. The aim of the study is to measure doses deposited at various depths as defined by ICRU 39 for individual and area monitoring purposes

  9. Estimation of skin, organ and effective doses of patients who undertake head CT scan in 4 medical radiography

    International Nuclear Information System (INIS)

    Bahreyni Toosi, M.T.; Khalilpour, M.

    2007-01-01

    Complete test of publication follows. CT was first introduced into clinical practice in 1972, and has since grown into one of the predominant diagnostic procedures. In this work we have estimated patient dose arising from CT examination of brain in four hospitals in Mashhad. Organ and effective doses were estimated for 123 patients who underwent CT examination of brain. 'ImPACT' version 0.99w was used to estimate organ and effective dose. ESD of same patients were measured by TLD-100. Brain examinations were performed with fixed kV, mA and T (slice thickness) for each scanner. The CT Scanners investigated in this study were GE HiLight, Siemens Somatom AR-T, Somatom Balance and Shimadzu SCT. Summary of our findings are as follows: Application of 'ImPACT' software enabled us to compute Bone marrow (red), Brain, Thyroid and effective doses of all patients. Table 1 shows the average organ dose (Brain, Bone marrow (red), Thyroid), mean effective dose and mean ESD were measured by TLD for each patients. Patients, who were scanned by Siemens Somatom AR-T, received maximum organ dose (brain) equal to 25.64 mGy and minimum organ dose equal to 0.21 mGy was delivered to thyroid of patients who were scanned by GE HiLight Scanner. Our average effective dose (0.54 ± 0.02 mSv) is smaller than the corresponding value (0.75 ± 0.03 mSv) obtained by Peter F. Caracappa (M.Sc dissertation submitted to the Faculty of Rensselaer Polytechnic Institute, Troy, New York April 2004). Scanning by Siemens Somatom AR-T, gave rise to maximum ESD (equal to 16.22 mGy). On the other hand minimum ESD (5.51 mGy) was achieved when patients were scanned by GE HiLight machine. ESD values and organ doses acquired in this work by two different methods, TLD measurement and computing by 'ImPACT' software; are in good agreement and this is an indication of the accuracy and validity of both sets of results.

  10. Selection of skin dose calculation methodologies

    International Nuclear Information System (INIS)

    Farrell, W.E.

    1987-01-01

    This paper reports that good health physics practice dictates that a dose assessment be performed for any significant skin contamination incident. There are, however, several methodologies that could be used, and while there is probably o single methodology that is proper for all cases of skin contamination, some are clearly more appropriate than others. This can be demonstrated by examining two of the more distinctly different options available for estimating skin dose the calculational methods. The methods compiled by Healy require separate beta and gamma calculations. The beta calculational method is the derived by Loevinger, while the gamma dose is calculated from the equation for dose rate from an infinite plane source with an absorber between the source and the detector. Healy has provided these formulas in graphical form to facilitate rapid dose rate determinations at density thicknesses of 7 and 20 mg/cm 2 . These density thicknesses equate to the regulatory definition of the sensitive layer of the skin and a more arbitrary value to account of beta absorption in contaminated clothing

  11. The relation between constitutional skin color and photosensitivity estimated from UV-induced erythema and pigmentation dose-response curves

    NARCIS (Netherlands)

    Westerhof, W.; Estevez-Uscanga, O.; Meens, J.; Kammeyer, A.; Durocq, M.; Cario, I.

    1990-01-01

    In 54 healthy volunteers we assessed predictors of sensitivity to ultraviolet (UV) light, including Fitzpatrick's sun reactive skin types and constitutional skin color, and compared these with one another and with responses of the skin to UV irradiation, as determined experimentally by a minimal

  12. Multilayer detector for measuring absorbed dose in skin

    International Nuclear Information System (INIS)

    Osanov, D.P.; Panova, V.P.; Shaks, A.I.

    1985-01-01

    A method of skin dosimetry using multilayer dosimeters is described that allows the skin-depth distribution of absorbed dose to be estimated. A method of quantitative estimation and prediction of the degree of skin radiation damage using a three-layer dosimeter is demonstrated. Dosimeters are holders of tissue-equivalent material that contain photographic film, a scintillator, thermoluminophor, or any other radiation-sensitive element

  13. Skin dose measurement with MICROSPEC-2 trademark

    International Nuclear Information System (INIS)

    Hsu, H.H.

    1997-01-01

    For many years, the Eberline HP-260 trademark beta detectors were used for skin dose measurements at Los Alamos National Laboratory. This detector does not measure the beta spectrum and the skin dose can only be determined if the contaminating radioactive isotope is known. A new product MICROSPEC-2 trademark, has been developed which consists of a small portable computer with a multichannel analyzer and a beta probe consisting of a phoswich detector. The system measures the beta spectrum and automatically folds in the beta fluence-to-dose conversion function to yield the skin dose

  14. Investigation of radiation skin dose in interventional cardiology

    International Nuclear Information System (INIS)

    Webster, C.M.; Horrocks, J.; Hayes, D.

    2001-01-01

    Background - The study investigated the radiation skin doses for interventional patients in cardiology; two procedures which have the highest radiation dose are Radiofrequency Catheter Ablation (RFCA) and Percutaneous Transluminal Coronary Angioplasty (PTCA). Methods and Results - 56 patients were randomly selected and investigated; 23 patients in the RFCA group and 33 in the PTCA group. Skin and effective dose were calculated from Dose Area Product (DAP). Thermoluminescent Dosimetry was the second method of dose measurement used. Patients were followed-up for a three month period to check for possible skin reactions resulting from the radiation dose during the procedure. Radiation skin doses in 14 patients were calculated to be more than 1 Gy, including three patients who received more than 2 Gy, the threshold dose for deterministic effects of radiation. 7 patients (12.5%) reported skin reactions as a result of the radiation received to their backs during the procedure. Mean DAP and estimated effective doses were 105 Gycm 2 and 22.5 mSv for RFCA, and 32 Gycm 2 and 6.2 mSv for PTCA procedures respectively. Conclusion - Complex procedures in Interventional Cardiology can exceed the threshold level for deterministic effects in the skin. (author)

  15. Calculational Tool for Skin Contamination Dose Assessment

    CERN Document Server

    Hill, R L

    2002-01-01

    Spreadsheet calculational tool was developed to automate the calculations preformed for dose assessment of skin contamination. This document reports on the design and testing of the spreadsheet calculational tool.

  16. A simplified model for predicting skin dose received by patients from ...

    African Journals Online (AJOL)

    Use of ionising radiation in any sector requires doses to be kept as low as reasonable achievable (ARALA). Thus, in keeping radiation dose to skin from diagnostic X-rays, as low as is required by this philosophy, it is useful to obtain an estimate of skin dose before the actual dose is administered. The aim of this paper is to ...

  17. Skin dose mapping for fluoroscopically guided interventions.

    Science.gov (United States)

    Johnson, Perry B; Borrego, David; Balter, Stephen; Johnson, Kevin; Siragusa, Daniel; Bolch, Wesley E

    2011-10-01

    To introduce a new skin dose mapping software system for interventional fluoroscopy dose assessment and to analyze the benefits and limitations of patient-phantom matching. In this study, a new software system was developed for visualizing patient skin dose during interventional fluoroscopy procedures. The system works by translating the reference point air kerma to the location of the patient's skin, which is represented by a computational model. In order to orient the model with the x-ray source, geometric parameters found within the radiation dose structured report (RDSR) are used along with a limited number of in-clinic measurements. The output of the system is a visual indication of skin dose mapped onto an anthropomorphic model at a resolution of 5 mm. In order to determine if patient-dependent and patient-sculpted models increase accuracy, peak skin dose was calculated for each of 26 patient-specific models and compared with doses calculated using an elliptical stylized model, a reference hybrid model, a matched patient-dependent model and one patient-sculpted model. Results were analyzed in terms of a percent difference using the doses calculated using the patient-specific model as the true standard. Anthropometric matching, including the use of both patient-dependent and patient-sculpted phantoms, was shown most beneficial for left lateral and anterior-posterior projections. In these cases, the percent difference using a reference model was between 8 and 20%, using a patient-dependent model between 7 and 15%, and using a patient-sculpted model between 3 and 7%. Under the table tube configurations produced errors less than 5% in most situations due to the flattening affects of the table and pad, and the fact that table height is the main determination of source-to-skin distance for these configurations. In addition to these results, several skin dose maps were produced and a prototype display system was placed on the in-clinic monitor of an interventional

  18. Skin dose variation: influence of energy

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

    2004-01-01

    Full text: This research aimed to quantitatively evaluate the differences in percentage dose of maximum for 6MV and 18MV x-ray beams within the first lcm of interactions. Thus provide quantitative information regarding the basal, dermal and subcutaneous dose differences achievable with these two types of high-energy x-ray beams. Percentage dose of maximum build up curves are measured for most clinical field sizes using 6MV and 18MV x-ray beams. Calculations are performed to produce quantitative results highlighting the percentage dose of maximum differences delivered to various depths within the skin and subcutaneous tissue region by these two beams Results have shown that basal cell layer doses are not significantly different for 6MV and 18Mv x-ray beams At depths beyond the surface and basal cell layer there is a measurable and significant difference in delivered dose. This variation increases to 20% of maximum and 22% of maximum at Imm and 1cm depths respectively. The percentage variations are larger for smaller field sizes where the photon in phantom component of the delivered dose is the most significant contributor to dose By producing graphs or tables of % dose differences in the build up region we can provide quantitative information to the oncologist for consideration (if skin and subcutaneous tissue doses are of importance) during the beam energy selection process for treatment. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  19. Internal dose estimates

    International Nuclear Information System (INIS)

    Wrenn, M.E.

    1977-01-01

    Internal doses, the procedures for making them and their significance has been reviewed. Effects of uranium, radium, lead-210, polonium-210, thorium in man are analysed based on data from tables and plots. Dosimetry of some ingested nuclides and inhalation dose due to radon-222, radon-220 and their daugther products are discussed [pt

  20. External contamination and skin dose. From ICRP and regulations to skin dose evaluation in practice

    International Nuclear Information System (INIS)

    Le Coulteulx, I.; Apretna, D.; Beaugerie, M.; Fenolland, J.; Frey, R.; Gonin, M.; Landry, B.; Laporte, E.; Le Guen, B.; Leval, D.

    2006-01-01

    Dose limitation to the skin is an objective of radiation protection. Our aim is to propose in case of skin contamination in EDF NPPs a simply, quickly and reproducible procedure for evaluating skin dose. French regulation admit an annual limit for skin dose over one square centimeter equal to 500 mSv. ICRP Publication 26 and 60 recommend that dose assessment be performed only if skin dose might be equal to or more than 50 mSv at basal cells. To respect this recommendation, an alert value (A) must be determined. This value is the lowest value of measurement from which dose assessment has to be made, based on the hypothesis that uninterrupted work time in controlled area is no more than four hours. This alert value (A) has been established for three external detection equipments, and for the ten radionuclides commonly detected. In case of external contamination, a first measurement is performed. If the value exceeds value (A), other measurements are instituted because skin dose evaluation needs to know other parameters as: - the radioactivity of the most contaminated square centimeter of the skin, - the identity of the radionuclides and their relative proportion. At the same time, we have to evaluate the length of the exposure. At last, we use different compiled results in a program developed from excel software which allow to calculate automatically the skin dose. This work has allowed us to publish an occupational health guideline about the assessment of skin dose in case of external contamination in EDF NPPs and to create an information booklet for workers. The authors propose to examine used methodology and to demonstrate the software. (authors)

  1. Calculation of skin dose due to beta contamination using the new quantity of the ICRP 116: the local skin dose

    International Nuclear Information System (INIS)

    Bourgois, L.; Menard, S.; Comte, N.

    2017-01-01

    Values of the new protection quantity Local Skin Dose 'LSD', introduced by the International Commission on Radiological Protection (ICRP) Publication 116, were calculated for 134 β - or β + emitting radionuclides, using the Monte Carlo code MCNP6. Two types of source geometry are considered: a point source and disc-type surface contamination (the source is placed in contact with the skin). This new protection quantity is compared with the operational quantity H2 (0.07, 0 deg.), leading us to conclude that, in accordance with the rules of the ICRP, the operational quantity over-estimates the protection quantity to a reasonable extent, except in very rare cases for very low average beta energies. Thus, with the new skin model described in ICRP 116, there are no longer any major differences between the operational quantities and protection quantities estimated with the skin model described in ICRP 74. (authors)

  2. Estimating physiological skin parameters from hyperspectral signatures

    Science.gov (United States)

    Vyas, Saurabh; Banerjee, Amit; Burlina, Philippe

    2013-05-01

    We describe an approach for estimating human skin parameters, such as melanosome concentration, collagen concentration, oxygen saturation, and blood volume, using hyperspectral radiometric measurements (signatures) obtained from in vivo skin. We use a computational model based on Kubelka-Munk theory and the Fresnel equations. This model forward maps the skin parameters to a corresponding multiband reflectance spectra. Machine-learning-based regression is used to generate the inverse map, and hence estimate skin parameters from hyperspectral signatures. We test our methods using synthetic and in vivo skin signatures obtained in the visible through the short wave infrared domains from 24 patients of both genders and Caucasian, Asian, and African American ethnicities. Performance validation shows promising results: good agreement with the ground truth and well-established physiological precepts. These methods have potential use in the characterization of skin abnormalities and in minimally-invasive prescreening of malignant skin cancers.

  3. Radiation dose estimates for radiopharmaceuticals

    International Nuclear Information System (INIS)

    Stabin, M.G.; Stubbs, J.B.; Toohey, R.E.

    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

  4. Dose factors for contamination of skin and clothing

    International Nuclear Information System (INIS)

    Henrichs, K.; Eiberweiser, C.; Paretzke, H.G.

    1985-11-01

    Methods are described for quantifying the radiation dose administered through radioactive contamination of the skin (and of clothing, in an approximative manner). The calculated results are presented in tables. The dose values established are of significance with regard to radiological assessment of contamination for the definition of dose limits, and for use as a criterion to select appropriate decontamination activities. Alpha, beta and monoenergetic electrons are of importance for estimating the absorbed dose in various skin depths, whereas for other body regions (as e.g. body organs) photon radiation has to be considered. The calculations are based on the assumption of homogeneous exposure of the skin, with the linear extension being large compared to the range of the emitted particle radiation. In order to be able to take into account potential penetration of radioactivity into deeper skin layers by diffusion or solution processes, the calculations have been made for contamination into various depths of the horny layers of the epidermis. The scheme of specific absorbed fraction (SAF) served as a basis for the uniform treatment of different radiation types for the calculation of dose values. (orig./HP) [de

  5. Correlation of patient maximum skin doses in cardiac procedures with various dose indicators

    International Nuclear Information System (INIS)

    Domienik, J.; Papierz, S.; Jankowski, J.; Peruga, J.Z.; Werduch, A.; Religa, W.

    2008-01-01

    In most countries of European Union, legislation requires the determination of the total skin dose received by patients during interventional procedures in order to prevent deterministic damages. Various dose indicators like dose-area product (DAP), cumulative dose (CD) and entrance dose at the patient plane (EFD) are used for patient dosimetry purposes in clinical practice. This study aimed at relating those dose indicators with doses ascribed to the most irradiated areas of the patient skin usually expressed in terms of local maximal skin dose (MSD). The study was performed in two different facilities for two most common cardiac procedures coronary angiography (CA) and percutaneous coronary interventions (PCI). For CA procedures, the registered values of fluoroscopy time, total DAP and MSD were in the range (0.7-27.3) min, (16-317) Gy cm 2 and (43-1507) mGy, respectively, and for interventions, accordingly (2.1-43.6) min, (17-425) Gy cm 2 , (71-1555) mGy. Moreover, for CA procedures, CD and EFD were in the ranges (295-4689) mGy and (121-1768) mGy and for PCI (267-6524) mGy and (68-2279) mGy, respectively. No general and satisfactory correlation was found for safe estimation of MSD. However, results show that the best dose indicator which might serve for rough, preliminary estimation is DAP value. In the study, the appropriate trigger levels were proposed for both facilities. (authors)

  6. Weldon Spring historical dose estimate

    International Nuclear Information System (INIS)

    Meshkov, N.; Benioff, P.; Wang, J.; Yuan, Y.

    1986-07-01

    This study was conducted to determine the estimated radiation doses that individuals in five nearby population groups and the general population in the surrounding area may have received as a consequence of activities at a uranium processing plant in Weldon Spring, Missouri. The study is retrospective and encompasses plant operations (1957-1966), cleanup (1967-1969), and maintenance (1969-1982). The dose estimates for members of the nearby population groups are as follows. Of the three periods considered, the largest doses to the general population in the surrounding area would have occurred during the plant operations period (1957-1966). Dose estimates for the cleanup (1967-1969) and maintenance (1969-1982) periods are negligible in comparison. Based on the monitoring data, if there was a person residing continually in a dwelling 1.2 km (0.75 mi) north of the plant, this person is estimated to have received an average of about 96 mrem/yr (ranging from 50 to 160 mrem/yr) above background during plant operations, whereas the dose to a nearby resident during later years is estimated to have been about 0.4 mrem/yr during cleanup and about 0.2 mrem/yr during the maintenance period. These values may be compared with the background dose in Missouri of 120 mrem/yr

  7. Weldon Spring historical dose estimate

    Energy Technology Data Exchange (ETDEWEB)

    Meshkov, N.; Benioff, P.; Wang, J.; Yuan, Y.

    1986-07-01

    This study was conducted to determine the estimated radiation doses that individuals in five nearby population groups and the general population in the surrounding area may have received as a consequence of activities at a uranium processing plant in Weldon Spring, Missouri. The study is retrospective and encompasses plant operations (1957-1966), cleanup (1967-1969), and maintenance (1969-1982). The dose estimates for members of the nearby population groups are as follows. Of the three periods considered, the largest doses to the general population in the surrounding area would have occurred during the plant operations period (1957-1966). Dose estimates for the cleanup (1967-1969) and maintenance (1969-1982) periods are negligible in comparison. Based on the monitoring data, if there was a person residing continually in a dwelling 1.2 km (0.75 mi) north of the plant, this person is estimated to have received an average of about 96 mrem/yr (ranging from 50 to 160 mrem/yr) above background during plant operations, whereas the dose to a nearby resident during later years is estimated to have been about 0.4 mrem/yr during cleanup and about 0.2 mrem/yr during the maintenance period. These values may be compared with the background dose in Missouri of 120 mrem/yr.

  8. How accurately can the peak skin dose in fluoroscopy be determined using indirect dose metrics?

    International Nuclear Information System (INIS)

    Jones, A. Kyle; Ensor, Joe E.; Pasciak, Alexander S.

    2014-01-01

    Purpose: Skin dosimetry is important for fluoroscopically-guided interventions, as peak skin doses (PSD) that result in skin reactions can be reached during these procedures. There is no consensus as to whether or not indirect skin dosimetry is sufficiently accurate for fluoroscopically-guided interventions. However, measuring PSD with film is difficult and the decision to do so must be madea priori. The purpose of this study was to assess the accuracy of different types of indirect dose estimates and to determine if PSD can be calculated within ±50% using indirect dose metrics for embolization procedures. Methods: PSD were measured directly using radiochromic film for 41 consecutive embolization procedures at two sites. Indirect dose metrics from the procedures were collected, including reference air kerma. Four different estimates of PSD were calculated from the indirect dose metrics and compared along with reference air kerma to the measured PSD for each case. The four indirect estimates included a standard calculation method, the use of detailed information from the radiation dose structured report, and two simplified calculation methods based on the standard method. Indirect dosimetry results were compared with direct measurements, including an analysis of uncertainty associated with film dosimetry. Factors affecting the accuracy of the different indirect estimates were examined. Results: When using the standard calculation method, calculated PSD were within ±35% for all 41 procedures studied. Calculated PSD were within ±50% for a simplified method using a single source-to-patient distance for all calculations. Reference air kerma was within ±50% for all but one procedure. Cases for which reference air kerma or calculated PSD exhibited large (±35%) differences from the measured PSD were analyzed, and two main causative factors were identified: unusually small or large source-to-patient distances and large contributions to reference air kerma from cone

  9. Estimation of Absorbed Dose in Occlusal Radiography

    International Nuclear Information System (INIS)

    Yoo, Young Ah; Choi, Karp Shick; Lee, Sang Han

    1990-01-01

    The purpose of this study was to estimate absorbed dose of each important anatomic site of phantom (RT-210 Head and Neck Section R, Humanoid Systems Co., U.S.A.) head in occlusal radiography. X-radiation dosimetry at 12 anatomic sites in maxillary anterior topography, maxillary posterior topography, mandibular anterior cross-section, mandibular posterior cross-section, mandibular anterior topographic, mandibular posterior topographic occlusal projection was performed with calcium sulfate thermoluminescent dosimeters under 70 Kvp and 15 mA, 1/4 second (8 inch cone ) and 1 second (16 inch cone) exposure time. The results obtained were as follows: Skin surface produced highest absorbed dose ranged between 3264 mrad and 4073 mrad but there was little difference between projections. In maxillary anterior topographic occlusal radiography, eyeballs, maxillary sinuses, and pituitary gland sites produced higher absorbed doses than those of other sites. In maxillary posterior topographic occlusal radiography, exposed eyeball site and exposed maxillary sinus site produced high absorbed doses. In mandibular anterior cross-sectional occlusal radiography, all sites were produced relatively low absorbed dose except eyeball sites. In Mandibular posterior cross-sectional occlusal radiography, exposed eyeball site and exposed maxillary sinus site were produced relatively higher absorbed doses than other sites. In mandibular anterior topographic occlusal radiography, maxillary sinuses, submandibular glands, and thyroid gland sites produced high absorbed doses than other sites. In mandibular posterior topographic occlusal radiography, submandibular gland site of the exposed side produced high absorbed dose than other sites and eyeball site of the opposite side produced relatively high absorbed dose.

  10. Report of task group on the biological basis for dose limitation in the skin

    International Nuclear Information System (INIS)

    1989-08-01

    Researchers have drawn attention to what they consider inconsistencies in the manner in which ICRP have considered skin in relation to the effective dose equivalent. They urge that the dose to the skin should be considered routinely for inclusion in the effective dose equivalent in the context of protection of individuals and population groups. They note that even with a weighting factor of only 0.01 that the dose to the skin can be a significant contributor to the effective dose equivalent including skin for practical exposure conditions. In the case of many exposures the risk to the skin can be ignored but exposure in an uniformly contaminated cloud that might occur with 85 Kr the dose to the skin could contribute 60% of the stochastic risk if included in the effective dose equivalent with a W T of 0.01. Through the years and even today the same questions about radiation effects in the skin and dosimetry keep being asked. This report collates the available data and current understanding of radiation effects on the skin, and may make it possible to estimate risks more accurately and to improve the approach to characterizing skin irradiations. 294 refs., 29 figs

  11. Technical background for shallow (skin) dose equivalent evaluations

    International Nuclear Information System (INIS)

    Ashley, J.C.; Turner, J.E.; Crawford, O.H.; Hamm, R.N.; Reaves, K.L.; McMahan, K.L.

    1991-01-01

    Department of Energy Order 5480.11 describes procedures for radiation protection for occupational workers. The revisions dealing with non-uniform exposure to the skin are the subject of this report. We describe measurements and analysis required to assess shallow (skin) dose equivalent from skin contamination. 6 refs., 4 tabs

  12. Characteristics of dosemeter types for skin dose measurements in practice

    International Nuclear Information System (INIS)

    Van, D. J.; Bosmans, H.; Marchal, G.; Wambersie, A.

    2005-01-01

    A growing number of papers report deterministic effects in the skin of patients who have undergone interventional radiological procedures. Dose measurements, and especially skin dose measurements, are therefore increasingly important. Methods and acceptable dosemeters are, however, not clearly defined. This paper is the result of a literature overview with regard to assessing the entrance skin dose during radiological examinations by putting a dosemeter on the patient's skin. The relevant intrinsic characteristics, as well as some examples of clinical use of the different detector types, are presented. In this respect, thermoluminescence, scintillation, semiconductor and film dosemeters are discussed and compared with respect to their practical use. (authors)

  13. Determination of Entrance Skin Doses and Organ Doses for Medical X Ray Examinations

    International Nuclear Information System (INIS)

    Tung, C.J.; Cheng, C.Y.; Chao, T.C.; Tsai, H.Y.

    1999-01-01

    A national survey of patient doses for diagnostic X ray radiographs is planned in Taiwan. Entrance skin doses and organ doses for all installed X ray machines will be investigated. A pilot study has been carried out for the national survey to develop a protocol for the dose assessment. Entrance skin doses and organ doses were measured by thermoluminescence dosemeters and calculated by Monte Carlo simulations for several X ray examinations. The conversion factor from free air entrance absorbed dose to entrance skin dose was derived. A formula for the computation of entrance skin doses from inputs of kV p , mA.s, source to skin distance, aluminium filtration, and generator rectifying was constructed. Organ doses were measured using a RANDO phantom and calculated using a mathematical phantom. All data will be passed to the Atomic Energy Council for developing a programme of national survey and regulatory controls for diagnostic X ray examinations. (author)

  14. Dose estimation by biological methods

    International Nuclear Information System (INIS)

    Guerrero C, C.; David C, L.; Serment G, J.; Brena V, M.

    1997-01-01

    The human being is exposed to strong artificial radiation sources, mainly of two forms: the first is referred to the occupationally exposed personnel (POE) and the second, to the persons that require radiological treatment. A third form less common is by accidents. In all these conditions it is very important to estimate the absorbed dose. The classical biological dosimetry is based in the dicentric analysis. The present work is part of researches to the process to validate the In situ Fluorescent hybridation (FISH) technique which allows to analyse the aberrations on the chromosomes. (Author)

  15. Estimation of exposed dose, 1

    International Nuclear Information System (INIS)

    Okajima, Shunzo

    1976-01-01

    Radioactive atomic fallouts in Nishiyama district of Nagasaki Prefecture are reported on the basis of the survey since 1969. In 1969, the amount of 137 Cs in the body of 50 inhabitants in Nishiyama district was measured using human counter, and was compared with that of non-exposured group. The average value of 137 Cs (pCi/kg) was higher in inhabitants in Nishiyama district (38.5 in men and 24.9 in females) than in the controls (25.5 in men and 14.9 in females). The resurvey in 1971 showed that the amount of 137 Cs was decreased to 76% in men and 60% in females. When the amount of 137 Cs in the body was calculated from the chemical analysis of urine, it was 29.0 +- 8.2 in men and 29.4 +- 26.2 in females in Nishiyama district, and 29.9 +- 8.2 in men and 29.4 +- 11.7 in females in the controls. The content of 137 Cs in soils and crops (potato etc.) was higher in Nishiyama district than in the controls. When the internal exposure dose per year was calculated from the amount of 137 Cs in the body in 1969, it was 0.29 mrad/year in men and 0.19 mrad/year in females. Finally, the internal exposure dose immediately after the explosion was estimated. (Serizawa, K.)

  16. A model for predicting skin dose received by patients from an x-ray ...

    African Journals Online (AJOL)

    Patient dosimetry has raised concern on quality assurance in hospitals. Several organisations and research groups have been advocating ways of minimising radiation dose received by patients in hospitals. In this paper we have shown that it is possible to obtain in a simple way a reasonable estimate of skin dose received ...

  17. Knowledge of doses from radiumtherapy for skin hemangioma in childhood

    International Nuclear Information System (INIS)

    Shamsaldin, A.; Diallo, I.; Ligot, L.; Chavaudra, J.; De-Vathaire, F.

    1997-01-01

    Before 1974 about 5000 children were irradiated at the Institut Gustave-Roussy for a skin hemangioma of whom 20% were treated with radium applicators. To evaluate the absorbed doses to these patients at any site, we have developed a software program which permits simulation of the actual patient and treatment conditions. Part of this software is devoted to constructing an Individual Computerized Tomography Anatomy (ICTA) based on real human transverse slices and auxological tables. From the generated phantom, 160 anatomical sites of epidemiological interest are defined and localized according to a Cartesian co-ordinate system. The gamma doses at all sites from Ra-226 applicators are calculated by an algorithm which permits separation of the radiation paths in air, tissue, and lungs. It includes a correction for attenuation and scatters in infinite and semi-infinite mediums. To evaluate the factor φ(r) for these corrections at any distance or position from the applicator, we have modelled the results from several Monte Carlo simulations. In the range of 1 to 10 cm, the φ(r) values obtained from our model showed good agreement with those obtained by published methods. For several cases, the absorbed doses at points in water and patients from radium applicators estimated by this software, were compared to those measured and estimated at the Karolinska Hospital. The results showed good agreement. (author)

  18. System for estimation of mean active bone marrow dose

    International Nuclear Information System (INIS)

    Ellis, R.E.; Healy, M.J.R.; Shleien, B.; Tucker, T.

    1975-09-01

    The exposure measurements, model and computer program for estimation of mean active bone marrow doses formerly employed in the 1962 British Survey of x-ray doses and proposed for application to x-ray exposure information obtained in the U.S. Public Health Service's X-Ray Exposure Studies (1966 and 1973) are described and evaluated. The method described is feasible for use to determine the mean active bone marrow doses to adults for examinations having a skin to source distance of 80 cm or less. For a greater SSD, as for example in chest x rays, a small correction in the calculation dose can be made

  19. Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy

    International Nuclear Information System (INIS)

    Kinhikar, Rajesh A.; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M.; Dhote, Dipak S.; Deshpande, Deepak D.

    2009-01-01

    The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

  20. Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy.

    Science.gov (United States)

    Kinhikar, Rajesh A; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M; Dhote, Dipak S; Deshpande, Deepak D

    2009-09-01

    The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

  1. Patient absorbed radiation doses estimation related to irradiation anatomy

    International Nuclear Information System (INIS)

    Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes

    2014-01-01

    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

  2. The MIRD method of estimating absorbed dose

    International Nuclear Information System (INIS)

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine

  3. Entrances skin dose distribution maps for interventional neuroradiological procedures: A preliminary study

    International Nuclear Information System (INIS)

    Rampado, O.; Ropolo, R.

    2005-01-01

    Does estimation in interventional neuroradiology can be useful to limit skin radiation injuries. The purpose of this study was to evaluate the role of entrance skin dose (ESD) maps in planning exposure condition optimisation. Thirteen cerebral angiography and five embolisation procedures were monitored, measuring ESD, dose-area product (DAP) and other operational parameters. A transmission ionisation chamber, simultaneously measuring air kerma and DAP, measured dose-related quantities. Data acquisition software collected dosimetric and geometrical data during the interventional procedure and provided a distribution map of ESD on a standard phantom digital image, with maximum value estimation. Values of 88-1710 mGy for maximum skin dose and 16.7-343 Gy cm 2 for DAP were found. These data confirm the possibility of deterministic effects during therapeutic interventional neuroradiological procedures like cerebral embolisation. ESD maps are useful to retrospectively study the exposure characteristics of a procedure and plan patient exposure optimisation. (authors)

  4. Fate of chemicals in skin after dermal application: does the in vitro skin reservoir affect the estimate of systemic absorption?

    International Nuclear Information System (INIS)

    Yourick, Jeffrey J.; Koenig, Michael L.; Yourick, Debra L.; Bronaugh, Robert L.

    2004-01-01

    Recent international guidelines for the conduct of in vitro skin absorption studies put forward different approaches for addressing the status of chemicals remaining in the stratum corneum and epidermis/dermis at the end of a study. The present study investigated the fate of three chemicals [dihydroxyacetone (DHA), 7-(2H-naphtho[1,2-d]triazol-2-yl)-3-phenylcoumarin (7NTPC), and disperse blue 1 (DB1)] in an in vitro absorption study. In these studies, human and fuzzy rat skin penetration and absorption were determined over 24 or 72 h in flow-through diffusion cells. Skin penetration of these chemicals resulted in relatively low receptor fluid levels but high skin levels. For DHA, penetration studies found approximately 22% of the applied dose remaining in the skin (in both the stratum corneum and viable tissue) as a reservoir after 24 h. Little of the DHA that penetrates into skin is actually available to become systemically absorbed. 7NTPC remaining in the skin after 24 h was approximately 14.7% of the applied dose absorbed. Confocal laser cytometry studies with 7NTPC showed that it is present across skin in mainly the epidermis and dermis with intense fluorescence around hair. For DB1, penetration studies found approximately 10% (ethanol vehicle) and 3% (formulation vehicle) of the applied dose localized in mainly the stratum corneum after 24 h. An extended absorption study (72 h) revealed that little additional DB1 was absorbed into the receptor fluid. Skin levels should not be considered as absorbed material for DHA or DB1, while 7NTPC requires further investigation. These studies illustrate the importance of determining the fate of chemicals remaining in skin, which could significantly affect the estimates of systemically available material to be used in exposure estimates. We recommend that a more conclusive means to determine the fate of skin levels is to perform an extended study as conducted for DB1

  5. The biological basis for dose limitation to the skin

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1992-01-01

    Ionizing radiation may cause deterministic effects and cancer. It has been the policy to base dose limits for radiation protection of the skin on the prevention of deterministic effects (1). In the case of cancer in general, dose limitation for radiation protection is based on limiting excess cancer mortality to low levels of radiation. Since skin cancers are seldom lethal, the general radiation protection standards will protect against an increase in excess mortality from skin cancer. However, with the dose limits selected to prevent deterministic effects, there is a significant probability of an excess incidence of skin cancer occurring as a result of exposure during a working lifetime. The induction of skin cancer by radiation is influenced significantly by subsequent exposure to ultraviolet radiation (UVR) from sunlight. This finding raises not only interesting questions about the mechanisms involved, but also about the differences in risk of skin cancer in different populations. The amount and distribution of melanin in the skin determines the degree of the effect of UVR. This paper discusses the mechanisms of the induction of both deterministic and stochastic effects in skin exposed to radiation in relation to radiation protection. (author)

  6. Valorization of the GAFCHROMIC XR-R film for radiation dose estimation in the skin; Valoracion de las peliculas Gafchromic XR-R para estimacion de dosis a piel en ''ablacion por radiofrecuencia''

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Garcia, M.; Otero Martinez, C.; Camino, X. M.; Sendon del Rio, J. R.; Luna Vega, V.; Lobato Busto, R.; Mosquera Sueiro, J.; Pombar Camean, M.

    2006-07-01

    The adequacy of the couple formed by the GAFCHROMIC XR-R film and the MICROTEK Scan Maker 8700 for skin dose determination has been evaluated. The main advantages are the ease of use the films, since it can be manipulated without special care and the ability to archive it in the dosimetric history of the patient. The main limiting factors coming from the scanner are the reproducibility over time and noise in the digitization; it is shown that this last component can be minimized at the cost of resolution. From the film itself, the limiting factors are the inter and intra film uniformity. Contributing an 6,5% to the overall uncertainty in dose determination. Overall, it has been shown that skin dose determination is possible with this film with an uncertainty below 10%. (Author)

  7. Characterization of a team intraoperative Radiation therapy and measurement of dose in skin with film radiochromic

    International Nuclear Information System (INIS)

    Onses Segarra, A.; Sancho Kolster, I.; Eraso Urien, A.; Pla Farnos, M. J.; Picon Olmos, C.

    2015-01-01

    This paper presents the results of the initial reference state of intraoperative radiotherapy equipment lntraBeam, for performing breast treatments are analyzed. To the initial reference team was established for the following dosimetric and geometric beam parameters: percentage depth dose, beam quality, isotropy, linearity and mechanical and geometric integrity for both the source RX as for different spherical applicators of the team. Based on these checks, a program of periodic quality control was established. One of the exclusion criteria for this treatment is that the tumor is less than l cm of the skin, yaque give doses received in this organ can be high. For this reason it is important to know exactly the absorbed dose in skin during these treatments. In this regard we have implemented a system for measuring the skin dose during treatment with Radiochromic film, placing 4 film segments in fixed positions of the skin around the surgical incision. It .ha obtained calibration curve of sterilized films and compared the results with a calibration beam megavoltage. The results of the skin dose measurements are compared with theoretical estimates given by the planning system equipment. The results indicate the need to measure individually the skin dose for these treatments. (Author)

  8. Skin dose assessment in routine personnel beta/gamma dosimetry

    International Nuclear Information System (INIS)

    Christensen, P.

    1980-01-01

    The International Commission on Radiological Protection (Publication 26) has recommended a tissue depth of 5 to 10 mg.cm -2 for skin dose assessments. This requirement is generally not fulfilled by routine monitoring procedures because of practical difficulties in using very thin dosemeters with low sensitivity and therefore a high minimum detectable dose. Especially for low-energy beta-ray exposures underestimations of the skin dose by a factor of more than ten may occur. Low-transparent graphite-mixed sintered LiF and Li 2 B 4 0 7 : Mn dosemeters were produced which show a skin-equivalent response to beta and gamma exposures over a wide range of energies. These have found wide-spread application for extremity dosimetry but have not yet been generally introduced in routine personnel beta/gamma monitoring. The following adaptations of existing routine monitoring systems for improved skin dose assessments have been investigated: 1) Placement of a supplementary, thin, skin-dose equivalent dosemeter in the TLD badge to give additional information on low-energy exposures. 2) Introduction of a second photomultiplier in the read-out chamber which enables a simultaneous determination of emitted TL from both sides of the dosemeter separately. This method makes use of the selfshielding of the dosemeter to give information on the low-energy dose contribution. 3) By diffusion of Li 2 B 4 0 7 into solid LiF-dosemeters it was possible to produce a surface layer with a new distinct glow-peak at about 340 deg C which is not present in the undiffused part of the LiF chip, and which can be utilized for the assessment of the skin-dose. Data on energy response and accuracy of dose measurement for beta/gamma exposures are given for the three methods and advantages and disadvantages are discussed (H.K.)

  9. UV-radiation and skin cancer dose effect curves

    International Nuclear Information System (INIS)

    Henriksen, T.; Dahlback, A.; Larsen, S.H.

    1988-08-01

    Norwegian skin cancer data were used in an attempt to arrive at the dose effect relationship for UV-carcinogenesis. The Norwegian population is relatively homogenous with regard to skin type and live in a country where the annual effective UV-dose varies by approximately 40 percent. Four different regions of the country, each with a broadness of 1 o in latitude (approximately 111 km), were selected . The annual effective UV-doses for these regions were calculated assuming normal ozone conditions throughout the year. The incidence of malignant melanoma and non-melanoma skin cancer (mainly basal cell carcinoma) in these regions were considered and compared to the annual UV-doses. For both these types of cancer a quadratic dose effect curve seems to be valid. Depletions of the ozone layer results in larger UV-doses which in turn may yield more skin cancer. The dose effect curves suggest that the incidence rate will increase by an ''amplification factor'' of approximately 2

  10. Dose estimation for paediatric cranial computed tomography

    International Nuclear Information System (INIS)

    Curci Daros, K.A.; Bitelli Medeiros, R.; Curci Daros, K.A.; Oliveira Echeimberg, J. de

    2006-01-01

    In the last ten years, the number of paediatric computed tomography (CT) scans have increased worldwide, contributing to higher population radiation dose. Technique diversification in paediatrics and different CT equipment technologies have led to various exposure levels complicating precise evaluation of doses and operational conditions necessary for good quality images. The objective of this study was to establish a quantitative relationship between absorbed dose and cranial region in children up to 6 years old undergoing CT exams. Methods: X-ray was measured on the cranial surface of 64 patients undergoing CT using thermoluminescent (T.L.) dosimeters. Forty T.L.D.100 thermoluminescent dosimeters (T.L.D.) were evenly distributed on each patients skin surface along the sagittal axis. Measurements were performed in facial regions exposed to scatter radiation and in the supratentorial and posterior fossa regions, submitted to primary radiation. T.L.D. were calibrated for 120 kV X-ray over the acrylic phantom. T.L. measurements were made with a Harshaw 4000 system. Patient mean T.L. readings were determined for position, pi, of T.L.D. and normalized to the maximum supratentorial reading. From integrating the linear T.L. density function (?) resulting from radiation distribution in each of the three exposed regions, dose fraction was determined in the region of interest, along with total dose under the technical conditions used in that specific exam protocol. For each T.L.D. position along the patient cranium, there were n T.L. measurements with 2% uncertainty due to T.L. reader, and 5% due to thermal treatment of dosimeters. Also, mean T.L. readings and their uncertainties were calculated for each patient at each position, p. Results: Mean linear T.L. density for the region exposed to secondary radiation defined by position, 0.3≤p≤6 cm, was ρ((p)=7.9(4)x10 -2 +7(5)x10 -5 p 4.5(4) cm -1 ; exposed to primary X-ray for the posterior fossa region defined by position

  11. Dose estimation for paediatric cranial computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Curci Daros, K.A.; Bitelli Medeiros, R. [Sao Paulo Univ. Federal (Brazil); Curci Daros, K.A.; Oliveira Echeimberg, J. de [Centro Univ. Sao Camilo, Sao Paulo (Brazil)

    2006-07-01

    In the last ten years, the number of paediatric computed tomography (CT) scans have increased worldwide, contributing to higher population radiation dose. Technique diversification in paediatrics and different CT equipment technologies have led to various exposure levels complicating precise evaluation of doses and operational conditions necessary for good quality images. The objective of this study was to establish a quantitative relationship between absorbed dose and cranial region in children up to 6 years old undergoing CT exams. Methods: X-ray was measured on the cranial surface of 64 patients undergoing CT using thermoluminescent (T.L.) dosimeters. Forty T.L.D.100 thermoluminescent dosimeters (T.L.D.) were evenly distributed on each patients skin surface along the sagittal axis. Measurements were performed in facial regions exposed to scatter radiation and in the supratentorial and posterior fossa regions, submitted to primary radiation. T.L.D. were calibrated for 120 kV X-ray over the acrylic phantom. T.L. measurements were made with a Harshaw 4000 system. Patient mean T.L. readings were determined for position, pi, of T.L.D. and normalized to the maximum supratentorial reading. From integrating the linear T.L. density function (?) resulting from radiation distribution in each of the three exposed regions, dose fraction was determined in the region of interest, along with total dose under the technical conditions used in that specific exam protocol. For each T.L.D. position along the patient cranium, there were n T.L. measurements with 2% uncertainty due to T.L. reader, and 5% due to thermal treatment of dosimeters. Also, mean T.L. readings and their uncertainties were calculated for each patient at each position, p. Results: Mean linear T.L. density for the region exposed to secondary radiation defined by position, 0.3{<=}p{<=}6 cm, was {rho}((p)=7.9(4)x10{sup -2}+7(5)x10{sup -5}p{sup 4.5(4)} cm{sup -1}; exposed to primary X-ray for the posterior fossa

  12. Clinical use of carbon-loaded thermoluminescent dosimeters for skin dose determination

    International Nuclear Information System (INIS)

    Ostwald, Patricia M.; Kron, Tomas; Hamilton, Christopher S.; Denham, James W.

    1995-01-01

    Purpose: Carbon-loaded thermoluminescent dosimeters (TLDs) are designed for surface/skin dose measurements. Following 4 years in clinical use at the Mater Hospital, the accuracy and clinical usefulness of the carbon-loaded TLDs was assessed. Methods and Materials: Teflon-based carbon-loaded lithium fluoride (LiF) disks with a diameter of 13 mm were used in the present study. The TLDs were compared with ion chamber readings and TLD extrapolation to determine the effective depth of the TLD measurement. In vivo measurements were made on patients receiving open-field treatments to the chest, abdomen, and groin. Skin entry dose or entry and exit dose were assessed in comparison with doses estimated from phantom measurements. Results: The effective depth of measurement in a 6 MV therapeutic x-ray beam was found to be about 0.10 mm using TLD extrapolation as a comparison. Entrance surface dose measurements made on a solid water phantom agreed well with ion chamber and TLD extrapolation measurements, and black TLDs provide a more accurate exit dose than the other methods. Under clinical conditions, the black TLDs have an accuracy of ± 5% (± 2 SD). The dose predicted from black TLD readings correlate with observed skin reactions as assessed with reflectance spectroscopy. Conclusion: In vivo dosimetry with carbon-loaded TLDs proved to be a useful tool in assessing the dose delivered to the basal cell layer in the skin of patients undergoing radiotherapy

  13. A model for predicting skin dose received by patients from an x-ray ...

    African Journals Online (AJOL)

    We have done this by modifying a model for predicting skin dose derived by Edmonds for a triple-phase generator. Results for 100 patients based on the triple-phase generator output show a reasonable average agreement (»1%) between our present model and the Edmonds's model. Although our earlier estimated ...

  14. In vitro modeling of skin dose and monitoring of DCA following therapeutic intervention

    International Nuclear Information System (INIS)

    Balajee, Adayabalam S.; Dainiak, Nicholas

    2016-01-01

    Human skin is the largest organ of the body accounting for approximately 16% of the total bodyweight. Skin is readily exposed to ionizing radiation during either accidental or intentional exposure such as radiotherapy or other medical procedures because it constitutes the interface between environment and internal organs. Estimation of accurate entrance skin dose and maximum absorbed dose (MAD) is crucial to prevent serious skin injuries. Cutaneous Radiation Syndrome (CRS) is defined by a number of pathological changes manifested in the skin and severity of these changes depend on Liner Energy Transfer (LET), dose, dose-rate, geometry of exposure and volume of body part exposed. In most of the radiological accident scenarios, reconstructive dosimetry in the skin has been performed using physical (thermoluminescence and optical stimulated luminescence), biological (cytogenetics) and computational methods/models to manage radiation exposed victims.Results of the cytogenetic testing performed at the CBL on a few patients will be discussed to illustrate the potential use of DCA and other cytogenetic techniques such as micronuclei and multicolor FISH in monitoring the health of radiotherapy patients

  15. Bayesian estimation of dose rate effectiveness

    International Nuclear Information System (INIS)

    Arnish, J.J.; Groer, P.G.

    2000-01-01

    A Bayesian statistical method was used to quantify the effectiveness of high dose rate 137 Cs gamma radiation at inducing fatal mammary tumours and increasing the overall mortality rate in BALB/c female mice. The Bayesian approach considers both the temporal and dose dependence of radiation carcinogenesis and total mortality. This paper provides the first direct estimation of dose rate effectiveness using Bayesian statistics. This statistical approach provides a quantitative description of the uncertainty of the factor characterising the dose rate in terms of a probability density function. The results show that a fixed dose from 137 Cs gamma radiation delivered at a high dose rate is more effective at inducing fatal mammary tumours and increasing the overall mortality rate in BALB/c female mice than the same dose delivered at a low dose rate. (author)

  16. [Evaluation of Organ Dose Estimation from Indices of CT Dose Using Dose Index Registry].

    Science.gov (United States)

    Iriuchijima, Akiko; Fukushima, Yasuhiro; Ogura, Akio

    Direct measurement of each patient organ dose from computed tomography (CT) is not possible. Most methods to estimate patient organ dose is using Monte Carlo simulation with dedicated software. However, dedicated software is too expensive for small scale hospitals. Not every hospital can estimate organ dose with dedicated software. The purpose of this study was to evaluate the simple method of organ dose estimation using some common indices of CT dose. The Monte Carlo simulation software Radimetrics (Bayer) was used for calculating organ dose and analysis relationship between indices of CT dose and organ dose. Multidetector CT scanners were compared with those from two manufactures (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare). Using stored patient data from Radimetrics, the relationships between indices of CT dose and organ dose were indicated as each formula for estimating organ dose. The accuracy of estimation method of organ dose was compared with the results of Monte Carlo simulation using the Bland-Altman plots. In the results, SSDE was the feasible index for estimation organ dose in almost organs because it reflected each patient size. The differences of organ dose between estimation and simulation were within 23%. In conclusion, our estimation method of organ dose using indices of CT dose is convenient for clinical with accuracy.

  17. Skin dose assessment in routine personnel beta/gamma dosimetry

    International Nuclear Information System (INIS)

    Christensen, P.

    1980-01-01

    Three alternative methods are outlined by which substantial improvements of the capabilities of existing routine monitoring systems for skin dose assessment can be obtained. The introduction of a supplementary skin dosemeter may be an attractive method for systems with badges that have a capability for an additional dosemeter already built-in. The two-side reading method has limited possibilities because of reduced accuracy for mixed radiation and technical difficulties in using it for TLD systems with planchet heating. The use of a boron diffused LiF layer for skin dose assessment seems to be most attractive method since the only modification needed here is replacement of a dosemeter. However the study of this method is so far only in a preliminary stage and further investigations are needed. (U.K.)

  18. Response of pig skin to fractionated radiation doses

    International Nuclear Information System (INIS)

    Wiernik, G.; Hopewell, J.W.; Patterson, T.J.S.; Young, C.M.A.; Foster, J.L.

    1977-01-01

    The individual components of a fractionated course of irradiation treatment have been considered separately. Methods of accurate measurement of individual parameters has brought to light different interpretations of the observations. Reasons are given for the necessity of having a radiobiological model which has a direct relevance to the clinical situation. Results are reported for fractionated regimes of irradiation in which the dose has been varied above and below normal tissue tolerance which has been equated with clinical skin necrosis. The components of the acute skin reaction, erythema, pigmentation and desquamation have been analysed separately and their contribution as a method of measurement assessed. Initially, the range of numerical scores attributed to erythema did not reach the scores attributed to necrosis but we now believe that radiation damage expressed as erythema can move directly into necrosis without passing through desquamation. Desquamation, on the other hand, only became a useful parameter at higher dose levels; it has also been shown to be a component associated with skin breakdown. Pigmentation showed no dose response at the dose levels employed in our experiments and it is our belief that this is due to this system being fully saturated under these circumstances. Measurement of the late radiation reaction in the skin has been considered in detail and our results have been expressed by comparing the relative lengths of irradiated and control fields in the same pig. From these findings iso-effect graphs have been constructed and time and fractionation factors have been derived. (author)

  19. Total skin electron irradiation: evaluation of dose uniformity throughout the skin surface

    International Nuclear Information System (INIS)

    Anacak, Yavuz; Arican, Zumre; Bar-Deroma, Raquel; Tamir, Ada; Kuten, Abraham

    2003-01-01

    In this study, in vivo dosimetic data of 67 total skin electron irradiation (TSEI) treatments were analyzed. Thermoluminescent dosimetry (TLD) measurements were made at 10 different body points for every patient. The results demonstrated that the dose inhomogeneity throughout the skin surface is around 15%. The homogeneity was better at the trunk than at the extratrunk points, and was worse when a degrader was used. There was minimal improvement of homogeneity in subsequent days of treatment

  20. Measurement of Skin Dose from Using the Treatment Immobilization Devices

    International Nuclear Information System (INIS)

    Je, Jae Yong; Park, Chul Woo; Noh, Kyung Suk

    2009-01-01

    The research was about the relation between the dorsal side dose measured by using the phantom body (Alderson Rando Phantom) and factors like contacted material of the patients, the size of the field, angle of incidence. Compared with mylar (tennis racket), the dose on 10 x 10 cm 2 field size of cotton was increased by 2% and by 8% in the case of breast board. In the case of 15 x 15 cm 2 field size, the dose was increased by 6% compared with 10 x 10 cm 2 size. The field size of 20 x 20 cm 2 resulted in 10% increase of dose, while 5 x 5 cm 2 produced 13% decrease. Compared with incident angle 0 degree, the cases for the incident angle 5 degrees had 0.4% less dose for breast board, 0.5% for tennis racket, 1.1% for cotton. The cases for the incident angle 10 degrees had 1.5% less dose for breast board, 1.9% for tennis racket, 2.6% for cotton. For the incident angle 15 degrees, breast board, tennis racket, cotton caused decrease of dose by 3.9%, 2.6%, 3.86% respectively. Resultantly carbon material can cause more skin dose in treatment field. By the results of this study, we recommend that one should avoid the contact between the carbon material and skin.

  1. Estimated radiation dose from timepieces containing tritium

    International Nuclear Information System (INIS)

    McDowell-Boyer, L.M.

    1980-01-01

    Luminescent timepieces containing radioactive tritium, either in elemental form or incorporated into paint, are available to the general public. The purpose of this study was to estimate potential radiation dose commitments received by the public annually as a result of exposure to tritium which may escape from the timepieces during their distribution, use, repair, and disposal. Much uncertainty is associated with final dose estimates due to limitations of empirical data from which exposure parameters were derived. Maximum individual dose estimates were generally less than 3 μSv/yr, but ranged up to 2 mSv under worst-case conditions postulated. Estimated annual collective (population) doses were less than 5 person/Sv per million timepieces distributed

  2. The radiation dose from a proposed measurement of arsenic and selenium in human skin

    Energy Technology Data Exchange (ETDEWEB)

    Gherase, Mihai R; Mader, Joanna E; Fleming, David E B, E-mail: mgherase@mta.c [Department of Physics, Mount Allison University, 67 York Street, Sackville, NB E4L 1E6 (Canada)

    2010-09-21

    Dose measurements following 10 min irradiations with a portable x-ray fluorescence spectrometer composed of a miniature x-ray tube and a silicon PiN diode detector were performed using thermoluminescent dosimeters consisting of LiF:Mg,Ti chips of 3 mm diameter and 0.4 mm thickness. The table-top setup of the spectrometer was used for all measurements. The setup included a stainless steel lid which served as a radiation shield. Two rectangular polyethylene skin/soft tissue phantoms with two cylindrical plaster of Paris bone phantoms were used to study the effect of x-ray beam attenuation and backscatter on the measured dose. Eight different irradiation experiments were performed. The average dose rate values measured with TLD chips within a 1 x 1 cm{sup 2} area were between 4.8 and 12.8 mGy min{sup -1}. The equivalent dose for a 1 x 1 cm{sup 2} skin area was estimated to be 13.2 mSv. The maximum measured dose rate values with a single TLD chip were between 7.5 and 25.1 mGy min{sup -1}. The effective dose corresponding to a proposed arsenic/selenium skin measurement was estimated to be 0.13 {mu}Sv for a 2 min irradiation.

  3. Estimation of dose from chromosome aberration rate

    International Nuclear Information System (INIS)

    Li Deping

    1990-01-01

    The methods and skills of evaluating dose from correctly scored shromsome aberration rate are presented, and supplemented with corresponding BASIC computer code. The possibility and preventive measures of excessive probability of missing score of the aberrations in some of the current routine score methods are discussed. The use of dose-effect relationship with exposure time correction factor G in evaluating doses and their confidence intervals, dose estimation in mixed n-γ exposure, and identification of high by nonuniform acute exposure to low LET radiation and its dose estimation are discussed in more detail. The difference of estimated dose due to whether the interaction between subleisoms produced by n and γ have been taken into account is examined. In fitting the standard dose-aberration rate curve, proper weighing of experiment points and comparison with commonly accepted values are emphasised, and the coefficient of variation σ y √y of the aberration rate y as a function of dose and exposure time is given. In appendix I and II, the dose-aberration rate formula is derived from dual action theory, and the time variation of subleisom is illustrated and in appendix III, the estimation of dose from scores of two different types of aberrations (of other related score) is illustrated. Two computer codes are given in appendix IV, one is a simple code, the other a complete code, including the fitting of standard curve. the skills of using compressed data storage, and the production of simulated 'data ' for testing the curve fitting procedure are also given

  4. Estimation of Thermal Sensation Based on Wrist Skin Temperatures

    Science.gov (United States)

    Sim, Soo Young; Koh, Myung Jun; Joo, Kwang Min; Noh, Seungwoo; Park, Sangyun; Kim, Youn Ho; Park, Kwang Suk

    2016-01-01

    Thermal comfort is an essential environmental factor related to quality of life and work effectiveness. We assessed the feasibility of wrist skin temperature monitoring for estimating subjective thermal sensation. We invented a wrist band that simultaneously monitors skin temperatures from the wrist (i.e., the radial artery and ulnar artery regions, and upper wrist) and the fingertip. Skin temperatures from eight healthy subjects were acquired while thermal sensation varied. To develop a thermal sensation estimation model, the mean skin temperature, temperature gradient, time differential of the temperatures, and average power of frequency band were calculated. A thermal sensation estimation model using temperatures of the fingertip and wrist showed the highest accuracy (mean root mean square error [RMSE]: 1.26 ± 0.31). An estimation model based on the three wrist skin temperatures showed a slightly better result to the model that used a single fingertip skin temperature (mean RMSE: 1.39 ± 0.18). When a personalized thermal sensation estimation model based on three wrist skin temperatures was used, the mean RMSE was 1.06 ± 0.29, and the correlation coefficient was 0.89. Thermal sensation estimation technology based on wrist skin temperatures, and combined with wearable devices may facilitate intelligent control of one’s thermal environment. PMID:27023538

  5. Proposal of a dosemeter for skin beta radiation dose assessment

    International Nuclear Information System (INIS)

    Rosa, L.A.R. da; Caldas, L.V.E.

    1987-08-01

    Beta radiation is, undoubtedly, less penetrating than X or gamma radiation. Thus, beta radiation sources external to the human body do not cause a significant irradiation of its deeper tissues. However, in some cases, they may contribute in a very important way to the irradiation of the lens of the eyes and, mainly, of the skin. Specially, the hands and finger tips may receive a high dose. In this work some relevant aspects of the individual monitoring in beta radiation fields are discussed and the importance of monitoring this kind of radiation in some activities where the skin absorbed dose may be a limiting factor is evidenced. The main characteristics of the thermoluminescent (TL) response of ultra-thin CaSO 4 : Dy detectors (UT-CaSO 4 : Dy) in the detection of this kind of radiation are also studied. The irradiation are performed with 90 Sr 90 Y, 204 TI and 147 Pm sources. The reproducibility, linearity, dependence on the absorbed dose rate, optical fading, energy and angular dependences of the detector TL responce are investigated. Transmission factors for different thicknesses of tissue equivalent material are obtained for the TL detectors using the three available beta sources. Based on the results obtained, a dosemeter for skin beta radiation absorbed dose assessment with an energy dependence better than 12% is proposed. (Author) [pt

  6. Evaluation of patients skin dose undergoing interventional cardiology procedure using radiochromic films

    International Nuclear Information System (INIS)

    Silva, Mauro W. Oliveira da; Canevaro, Lucia V.; Rodrigues, Barbara B. Dias

    2011-01-01

    In interventional cardiology (IC), coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) procedures are the most frequent ones. Since the 1990s, the number of IC procedures has increased rapidly. It is also known that these procedures are associated with high radiation doses due to long fluoroscopy time (FT) and large number of cine-frames (CF) acquired to document the procedure. Mapping skin doses in IC is useful to find the probability of skin injuries, to detect areas of overlapping field, and to get a permanent record of the most exposed areas of skin. The purpose of this study was to estimate the maximum skin dose (MSD) in patients undergoing CA and PTCA, and to compare these values with the reference levels proposed in the literature. Patients' dose measurements were carried out on a sample of 38 patients at the hemodynamic department, in four local hospitals in Rio de Janeiro, Brazil, using Gafchromic XR-RV2 films. In PTCA procedures, the median and third quartile values of MSD were estimated at 2.5 and 5.3 Gy, respectively. For the CA procedures, the median and third quartile values of MSD were estimated at 0.5 and 0.7 Gy, respectively. In this paper, we used the Pearson's correlation coefficient (r), and we found a fairly strong correlation between FT and MSD (r=0.8334, p<0.0001), for CA procedures. The 1 Gy threshold for deterministic effects was exceeded in nine patients. The use of Gafchromic XR-RV2 films was shown to be an effective method to measure MSD and the dose distribution map. The method is effective to identify the distribution of radiation fields, thus allowing the follow-up of the patient to investigate the appearance of skin injuries. (author)

  7. Fetus dose estimate of a pregnant worker

    International Nuclear Information System (INIS)

    Castro, P.; Espana, M.L.; Sevillano, D.; Minguez, C.; Ferrer, C.; Lopez Franco, P.

    2006-01-01

    A female employee working in diagnostic radiology should take additional controls to protect the unborn child from ionizing radiations. The fetus is particularly sensitive to the effects of x-rays and, so, the determination of the equivalent dose to the unborn child is of interest for risk estimates from occupational exposures of the pregnant workers. The ian of this study is to develop a method for fetus dose estimate of a pregnant worker who participates in interventional radiology procedures. Factors for converting dosemeter readings to equivalent dose to the fetus have been measured using thermoluminescence dosimetry. Equivalent dose to the uterus is used to simulate the equivalent dose to the fetus during the first two months of pregnancy. Measurements at different depths are made to consider the variations in the position of the uterus between pregnant women. The normalized doses obtained are dependent on the beam quality. Accurate estimation of fetus doses due to occupational exposures can be made using the data provided in the current study. (Author)

  8. Skin Dose Equivalent Measurement from Neutron-Deficient Isotopes

    International Nuclear Information System (INIS)

    Hsu, Hsiao-Hua; Costigan, Steve A.; Romero, Leonard L.; Whicker, Jeffrey J.

    1997-12-01

    Neutron-deficient-isotopes decay via positron emission and/or electron capture often followed by x-ray, gamma-ray, and 0.511 MeV photons from positron annihilation. For cases of significant area and/or personnel contamination with these isotopes, determination of skin dose equivalent (SDE) is required by 10CFR835. For assessment of SDE, we evaluated the MICROSPEC-2(TM) system manufactured by Bubble Technology Industries of Canada which uses three different probes for dose measurement. We used two probes: (1) the X-probe which measures lower energy (4 - 120 keV) photon energy distributions and determines deep dose equivalent, SDE and dose equivalent to eyes, and (2) the B-probe which measures electron (positron) energy distributions, and determines skin dose equivalent. Also, the measured photon and beta spectra can be used to identify radioactive isotopes in the contaminated area. Measurements with several neutron-deficient sources showed that this system provided reasonably accurate SDE rate measurements when compared with calculated benchmark SDE rates with an average percent difference of 40%. Variations were expected because of differences between the assumed geometries used by MlCROSPEC-2 and the calculations when compared to the measurement conditions

  9. Association Between Maximal Skin Dose and Breast Brachytherapy Outcome: A Proposal for More Rigorous Dosimetric Constraints

    International Nuclear Information System (INIS)

    Cuttino, Laurie W.; Heffernan, Jill; Vera, Robyn; Rosu, Mihaela; Ramakrishnan, V. Ramesh; Arthur, Douglas W.

    2011-01-01

    Purpose: Multiple investigations have used the skin distance as a surrogate for the skin dose and have shown that distances 4.05 Gy/fraction. Conclusion: The initial skin dose recommendations have been based on safe use and the avoidance of significant toxicity. The results from the present study have suggested that patients might further benefit if more rigorous constraints were applied and if the skin dose were limited to 120% of the prescription dose.

  10. Kodak EDR2 film for patient skin dose assessment in cardiac catheterization procedures.

    Science.gov (United States)

    Morrell, R E; Rogers, A T

    2006-07-01

    Patient skin doses were measured using Kodak EDR2 film for 20 coronary angiography (CA) and 32 percutaneous transluminal coronary angioplasty (PTCA) procedures. For CA, all skin doses were well below 1 Gy. However, 23% of PTCA patients received skin doses of 1 Gy or more. Dose-area product (DAP) was also recorded and was found to be an inadequate indicator of maximum skin dose. Practical compliance with ICRP recommendations requires a robust method for skin dosimetry that is more accurate than DAP and is applicable over a wider dose range than EDR2 film.

  11. Estimation of dose in dental radiology exams in critical regions

    International Nuclear Information System (INIS)

    Bonzoumet, S.P.J.; Braz, D.; Padilha, Lucas

    2005-01-01

    The objective of this paper is to estimate the values of doses, which are absorbed dose to the lens and thyroid in a dental X-ray. Thermoluminescence dosimeters were used, once they provide a reading of quality and effectiveness. This study was based on dental exams conducted in patients in order to estimate the dose that disperses to the lens of the eye and for the thyroid during an intraoral exam. Data collection took place in two institutions, one governmental, which had the device SELETRONIC 70X and other particular. This study showed that there is a considerable variation between the appliances. Using the appliance DABI 1070, there was a greater absorption of radiation in the right eye (values greater than 5 mGy) and a lower dose in the thyroid, and the Seletronic 70X presented an incidence of higher dose deposited in the skin and in other points there was a balance in the values. In the appliance SELETRONIC 70X, there was again a greater absorption of radiation in the right eye and a lower setting in the thyroid. The excessive dose, besides does not favor at all for the quality of radiograph, represents a risk for the patient who absorbs unnecessary and harmful radiation to the body

  12. Radon dose to the skin and the possible induction of skin cancers

    International Nuclear Information System (INIS)

    Eatough, J.P.; Henshaw, D.L.

    1991-01-01

    The radon related alpha particle dose equivalent to the basal layer of the epidermis has been calculated and found to be at least 2 mSv.y -1 , for exposed skin at the UK average radon exposure of 20 Bq.m -3 . A considerably greater dose equivalent may be received at this same radon concentration depending on the plateout conditions. Using standard risk factors 13% of skin cancers would theoretically be attributed to radon at the UK average exposure of 20 Bq.m -3 . Direct studies of skin cancer and radon in the home are needed before the validity of this prediction can be established. There is little evidence from high dose studies suggesting the induction of malignant melanoma by ionising radiation, although some circumstantial evidence exists, and the possibility that radon may be a co-factor with UV light in the induction of malignant melanoma, should not be dismissed. Due to the nature of the radiation risk factors the majority of any skin cancers linked to radon will simultaneously be linked to ultraviolet light exposure. (author)

  13. Using a thermoluminescent dosimeter to evaluate the location reliability of the highest–skin dose area detected by treatment planning in radiotherapy for breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Li-Min, E-mail: limin.sun@yahoo.com [Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China); Huang, Chih-Jen [Department of Radiation Oncology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung City, Taiwan (China); Faculty of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung City, Taiwan (China); College of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung City, Taiwan (China); Chen, Hsiao-Yun [Department of Radiation Oncology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung City, Taiwan (China); Meng, Fan-Yun [Department of General Surgery, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China); Lu, Tsung-Hsien [Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China); Tsao, Min-Jen [Department of General Surgery, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China)

    2014-01-01

    Acute skin reaction during adjuvant radiotherapy for breast cancer is an inevitable process, and its severity is related to the skin dose. A high–skin dose area can be speculated based on the isodose distribution shown on a treatment planning. To determine whether treatment planning can reflect high–skin dose location, 80 patients were collected and their skin doses in different areas were measured using a thermoluminescent dosimeter to locate the highest–skin dose area in each patient. We determined whether the skin dose is consistent with the highest-dose area estimated by the treatment planning of the same patient. The χ{sup 2} and Fisher exact tests revealed that these 2 methods yielded more consistent results when the highest-dose spots were located in the axillary and breast areas but not in the inframammary area. We suggest that skin doses shown on the treatment planning might be a reliable and simple alternative method for estimating the highest skin doses in some areas.

  14. Using a thermoluminescent dosimeter to evaluate the location reliability of the highest–skin dose area detected by treatment planning in radiotherapy for breast cancer

    International Nuclear Information System (INIS)

    Sun, Li-Min; Huang, Chih-Jen; Chen, Hsiao-Yun; Meng, Fan-Yun; Lu, Tsung-Hsien; Tsao, Min-Jen

    2014-01-01

    Acute skin reaction during adjuvant radiotherapy for breast cancer is an inevitable process, and its severity is related to the skin dose. A high–skin dose area can be speculated based on the isodose distribution shown on a treatment planning. To determine whether treatment planning can reflect high–skin dose location, 80 patients were collected and their skin doses in different areas were measured using a thermoluminescent dosimeter to locate the highest–skin dose area in each patient. We determined whether the skin dose is consistent with the highest-dose area estimated by the treatment planning of the same patient. The χ 2 and Fisher exact tests revealed that these 2 methods yielded more consistent results when the highest-dose spots were located in the axillary and breast areas but not in the inframammary area. We suggest that skin doses shown on the treatment planning might be a reliable and simple alternative method for estimating the highest skin doses in some areas

  15. Dosimetric effects of thermoplastic immobilizing devices on skin dose

    International Nuclear Information System (INIS)

    Adu-Poku Olivia

    2017-07-01

    This work shows the increase in surface dose caused by thermoplastic immobilizing masks used for positioning and immobilization of patients. Thermoplastics are organic materials which soften when they are heated. They can be formed after softening and retain their final shape when cooled. The use of these thermoplastic masks are relevant during patient treatment. However, it can lead to an increased skin dose. Measurements were done at source-to-surface distance of 80 cm for external radiation beams produced by cobalt 60 using the Farmer type ionization chamber and the Unidos electrometer. Measurements were carried out using various mask thicknesses and no mask material on a solid water phantom. The thermoplastic percentage depth dose (PDD), equivalent thickness of water of the various thicknesses of the mask and surface doses were determined. The increase in the surface dose caused by the thermoplastic mask was compared by looking at the PDD at depth 0 with and without the mask present and was found to increase between 0.76 and 0.79% with no mask for a field size of 5 x 5 cm 2 . It was found that, the presence of the mask shifted the percentage depth dose curve to lower values. The physical thermoplastic thickness was measured to be between 2.30 and 1.80 mm, and the equivalent thicknesses of water, d e , were determined to be 1.2, 1.15, 1.10 and 1.09 and 1.00 mm for the unstretched, 5 cm stretched, 10 cm stretched, 15 cm stretched and 20 cm stretched masks, respectively. This meant that, as the mask thickness decreased, its water equivalent thickness also decreased. The presence of the mask material did not increase the skin dose significantly ( less than 1%). (au)

  16. Assessment of patients' skin dose during interventional cardiology procedures

    International Nuclear Information System (INIS)

    Tsapaki, V.; Vardalaki, E.; Kottou, S.; Molfetas, M.; Neofotistou, V.

    2002-01-01

    During the last 30 years the use of Interventional Cardiology (IC) procedures has increased significantly, mainly due to the benefits and advantages of the method that offers more accurate diagnosis and treatment along with less complications and hospitalization. However, IC procedures are based on the use of x-ray radiation, mostly localized at certain areas of patient's body and for extended periods of time. Consequently, patient may receive high radiation dose and deterministic effects, such as erythema, epilation or even dermal necrosis may be observed. Therefore, the need for reducing radiation dose is highly important. In order to achieve this, good knowledge of the dose levels delivered to the patient during IC procedures is essential since radiation effects are known to increase with dose. It is of great interest to know the point where the maximum skin dose (MSD) is noted since individual sensitivity may vary. MSDs greater than 1 Gy should be recorded. Patient dosimetry during IC procedures is a complex task since these type of procedures depend on various factors, such as complexity and severity of case, different specifications of x-ray equipment and patient's physical characteristics. Moreover, cardiologist's experience plays an important role. For these reasons, Food and Drug Administration (FDA), the International Commission on Radiological Protection (ICRP) as well as the World Health Organization (WHO), have published documents on radiation safety and ways to reduce skin injuries during IC procedures. Various methods have been proposed for measuring MSD such as the use of slow radiotherapy films, thermoluminescent detectors (TLD), scintillation detectors, Dose-Area Product (DAP) meter, as well as a combination of DAP and air kerma. A literature review on MSDs measured during IC procedures showed that doses ranged from 300 to 43000 mGy

  17. Dose estimation for space radiation protection

    International Nuclear Information System (INIS)

    Xu Feng; Xu Zhenhua; Huang Zengxin; Jia Xianghong

    2007-01-01

    For evaluating the effect of space radiation on human health, the dose was estimated using the models of space radiation environment, models of distribution of the spacecraft's or space suit's mass thickness and models of human body. The article describes these models and calculation methods. (authors)

  18. Multiple methods for assessing the dose to skin exposed to radioactive contamination

    International Nuclear Information System (INIS)

    Dubeau, J.; Heinmiller, B.E.; Corrigan, M.

    2017-01-01

    There is the possibility for a worker at a nuclear installation, such as a nuclear power reactor, a fuel production facility or a medical facility, to come in contact with radioactive contaminants. When such an event occurs, the first order of business is to care for the worker by promptly initiating a decontamination process. Usually, the radiation protection personnel performs a G-M pancake probe measurement of the contamination in situ and collects part or all of the radioactive contamination for further laboratory analysis. The health physicist on duty must then perform, using the available information, a skin dose assessment that will go into the worker's permanent dose record. The contamination situations are often complex and the dose assessment can be laborious. This article compares five dose assessment methods that involve analysis, new technologies and new software. The five methods are applied to 13 actual contamination incidents consisting of direct skin contact, contamination on clothing and contamination on clothing in the presence of an air gap between the clothing and the skin. This work shows that, for the cases studied, the methods provided dose estimates that were usually within 12% (1σ) of each other, for those cases where absolute activity information for every radionuclide was available. One method, which relies simply on a G-M pancake probe measurement, appeared to be particularly useful in situations where a contamination sample could not be recovered for laboratory analysis. (authors)

  19. VARSKIN MOD 2 and SADDE MOD2: Computer codes for assessing skin dose from skin contamination

    International Nuclear Information System (INIS)

    Durham, J.S.

    1992-12-01

    The computer code VARSKIN has been modified to calculate dose to skin from three-dimensional sources, sources separated from the skin by layers of protective clothing, and gamma dose from certain radionuclides correction for backscatter has also been incorporated for certain geometries. This document describes the new code, VARSKIN Mod 2, including installation and operation instructions, provides detailed descriptions of the models used, and suggests methods for avoiding misuse of the code. The input data file for VARSKIN Mod 2 has been modified to reflect current physical data, to include the contribution to dose from internal conversion and Auger electrons, and to reflect a correction for low-energy electrons. In addition, the computer code SADDE: Scaled Absorbed Dose Distribution Evaluator has been modified to allow the generation of scaled absorbed dose distributions for mixtures of radionuclides and intereat conversion and Auger electrons. This new code, SADDE Mod 2, is also described in this document. Instructions for installation and operation of the code and detailed descriptions of the models used in the code are provided

  20. Skin dose reduction by a clinically viable magnetic deflector

    Energy Technology Data Exchange (ETDEWEB)

    Butson, M.J.; Carolan, M.; Metcalfe, J.N. [Illawarra Cancer Centre, NSW (Australia). Department of Radiotherapy]|[University of Wollongong, NSW (Australia). Department of Physics; Mathur, J.N. [University of Wollongong, NSW (Australia). Department of Physics; Yu, P.; Young, E. [City University of Hong Kong, Kowloon (Hong Kong). Department of Physics; Kan, M. [Hong Kong Polytechnic University, Kowloon (Hong Kong). Department of Optometry and Radiography]|[City University of Hong Kong, Kowloon (Hong Kong). Department of Physics

    1997-06-01

    A variable magnetic deflector which attaches onto the treatment head of a linear accelerator has reduced skin dose by as much as 65% for 6MV x-rays. The magnetic deflector is constructed from Neodymium Iron Boron (NdFeB) rare earth magnets. It weighs approximately 15 kg and is designed to easily fit onto the accessory mount of a clinical linear accelerator. All field sizes are attainable up to 35 cm x 35 cm at 100 cm SSD. The gap between the magnetic poles can be adjusted, providing the highest field strength for each field size. Magnetic field strengths up to 0.55 Tesla are attainable. For a 6MV x-ray beam with a 10 mm perspex block tray, surface dose is reduced from 29% to 14% and from 59% to 37% for a 20 cm x 20 cm and 35 cm x 35 cm field size, respectively. Results at varying SSD`s have shown at least 10 cm of space must be allowed between the magnets and patient for adequate reduction of skin dose through removal of electron contaminants. (authors). 14 refs., 6 figs.

  1. Skin dose reduction by a clinically viable magnetic deflector

    International Nuclear Information System (INIS)

    Butson, M.J.; Carolan, M.; Metcalfe, J.N.; University of Wollongong, NSW; Mathur, J.N.; Yu, P.; Young, E.; Kan, M.; City University of Hong Kong, Kowloon

    1997-01-01

    A variable magnetic deflector which attaches onto the treatment head of a linear accelerator has reduced skin dose by as much as 65% for 6MV x-rays. The magnetic deflector is constructed from Neodymium Iron Boron (NdFeB) rare earth magnets. It weighs approximately 15 kg and is designed to easily fit onto the accessory mount of a clinical linear accelerator. All field sizes are attainable up to 35 cm x 35 cm at 100 cm SSD. The gap between the magnetic poles can be adjusted, providing the highest field strength for each field size. Magnetic field strengths up to 0.55 Tesla are attainable. For a 6MV x-ray beam with a 10 mm perspex block tray, surface dose is reduced from 29% to 14% and from 59% to 37% for a 20 cm x 20 cm and 35 cm x 35 cm field size, respectively. Results at varying SSD's have shown at least 10 cm of space must be allowed between the magnets and patient for adequate reduction of skin dose through removal of electron contaminants. (authors)

  2. Estimation of 18FDG doses's cost

    International Nuclear Information System (INIS)

    Hamza, Fatma; Amouri, W.; Jardak, I.; Kallel, F.; Charfeddine, S.; Guermazi, F.

    2013-01-01

    The cyclotron facility, essentially for medical use, is far from being a simple establishment of a dedicated device to accelerate particles producing a beta plus emitter radioelement. The cyclotron site encompasses more over all necessary equipments for the production and the quality control of considered radiotracer that 18 FDG is just one example. This facility is subject to strict standards in terms of radiopharmaceutical production, radiation level, pressure level and airflow resulting in the production of a drug submitted to the MA (Marketing Authorization). These multiple factors directly influence the final cost of the dose that remains to be reachable by the patient. The aim of this work is to estimate the cost of a dose of 18 FDG to ensure financial viability of the project while accessible to the patient. The cost of the facility will entail the following: buildings and utilities, equipment and operational cost. This calculation is possible only if we define in advance the type of cyclotron, which is bound to the market needs in particular the number of PET facilities, the number of scans per day and the radioactive decay of radioelement. Our study represents a simulation that considers some hypothesis. We assumed that the cyclotron is installed in Sousse and that the PET facilities number (positon emission tomography) is 6 in which 4 are located 2 hours away. For a PET scan, the average dose per patient is about 350 MBq (5 MBq/kg) and the exam duration is about 45 minutes. Each center performs 10 tests per day. In terms of fees, we considered device and building's cost, facility amortization, consumables (target, marking accessories), maintenance, remuneration expense and the annual electricity consumption. All our calculations have been reported to the number of working days per year. The estimates were made outside the customs duties and technical assistance that may last up to 2 years. Requirements and needs were estimated at 5.4 curies per day. For

  3. New risk estimates at low doses

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1992-01-01

    The age of molecular radiation epidemiology may be at hand. The techniques are available to establish with the degree of precision required to determine whether agent-specific mutations can be identified consistently. A concerted effort to examine radiation-induced changes in as many relevant genes as possible appears to be justified. Cancers in those exposed to low doses of ionizing radiation should be chosen for the investigation. Parallel studies of radiation-induced cancers in experimental animals would not only complement the human studies, but perhaps reveal approaches to extrapolation of risk estimates across species. A caveat should be added to this optimistic view of what molecular studies might contribute to the knotty problem of risk estimates at low doses. The suggestions are made by one with no expertise in the field of molecular biology

  4. SU-F-P-19: Fetal Dose Estimate for a High-Dose Fluoroscopy Guided Intervention Using Modern Data Tools

    Energy Technology Data Exchange (ETDEWEB)

    Moirano, J [University of Washington, Seattle, WA (United States)

    2016-06-15

    Purpose: An accurate dose estimate is necessary for effective patient management after a fetal exposure. In the case of a high-dose exposure, it is critical to use all resources available in order to make the most accurate assessment of the fetal dose. This work will demonstrate a methodology for accurate fetal dose estimation using tools that have recently become available in many clinics, and show examples of best practices for collecting data and performing the fetal dose calculation. Methods: A fetal dose estimate calculation was performed using modern data collection tools to determine parameters for the calculation. The reference point air kerma as displayed by the fluoroscopic system was checked for accuracy. A cumulative dose incidence map and DICOM header mining were used to determine the displayed reference point air kerma. Corrections for attenuation caused by the patient table and pad were measured and applied in order to determine the peak skin dose. The position and depth of the fetus was determined by ultrasound imaging and consultation with a radiologist. The data collected was used to determine a normalized uterus dose from Monte Carlo simulation data. Fetal dose values from this process were compared to other accepted calculation methods. Results: An accurate high-dose fetal dose estimate was made. Comparison to accepted legacy methods were were within 35% of estimated values. Conclusion: Modern data collection and reporting methods ease the process for estimation of fetal dose from interventional fluoroscopy exposures. Many aspects of the calculation can now be quantified rather than estimated, which should allow for a more accurate estimation of fetal dose.

  5. Assessment of peak skin dose in interventional cardiology: A comparison between Gafchromic film and dosimetric software em.dose.

    Science.gov (United States)

    Greffier, J; Van Ngoc Ty, C; Bonniaud, G; Moliner, G; Ledermann, B; Schmutz, L; Cornillet, L; Cayla, G; Beregi, J P; Pereira, F

    2017-06-01

    To compare the use of a dose mapping software to Gafchromic film measurement for a simplified peak skin dose (PSD) estimation in interventional cardiology procedure. The study was conducted on a total of 40 cardiac procedures (20 complex coronary angioplasty of chronic total occlusion (CTO) and 20 coronary angiography and coronary angioplasty (CA-PTCA)) conducted between January 2014 to December 2015. PSD measurement (PSD Film ) was obtained by placing XR-RV3 Gafchromic under the patient's back for each procedure. PSD (PSD em.dose ) was computed with the software em.dose©. The calculation was performed on the dose metrics collected from the private dose report of each procedure. Two calculation methods (method A: fluoroscopic kerma equally spread on cine acquisition and B: fluoroscopic kerma is added to one air Kerma cine acquisition that contributes to the PSD) were used to calculate the fluoroscopic dose contribution as fluoroscopic data were not recorded in our interventional room. Statistical analyses were carried out to compare PSD Film and PSD em.dose . The PSD Film median (1st quartile; 3rd quartile) was 0.251(0.190;0.336)Gy for CA-PTCA and 1.453(0.767;2.011)Gy for CTO. For method-A, the PSD em.dose was 0.248(0.182;0.369)Gy for CA-PTCA and 1.601(0.892;2.178)Gy for CTO, and 0.267(0.223;0.446)Gy and 1.75 (0.912;2.584)Gy for method-B, respectively. For the two methods, the correlation between PSD Film and PSD em.dose was strong. For all cardiology procedures investigated, the mean deviation between PSD Film and PSD em.dose was 3.4±21.1% for method-A and 17.3%±23.9% for method-B. The dose mapping software is convenient to calculate peak skin dose in interventional cardiology. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  6. Evaluation of radiological protection and dose of skin entrance in paediatric dentistry examinations

    International Nuclear Information System (INIS)

    Khoury, Helen Jamil; Silveira, Marcia Maria Fonseca da; Couto, Geraldo Bosco Lindoso; Brasileiro, Izabela Vanderley

    2005-01-01

    In this work the radiological protection conditions and dose at the entrance of pediatric patients undergoing dental intraoral radiographs were evaluated. The study was conducted in two clinics of the dentistry course at the Federal University of Pernambuco, Recife, PB, Brazil, equipped with conventional X-ray apparatus, with 60 and 70 kV. 254 exams of 113 patients between the ages of 3 to 12 years were evaluated. The skin entrance dose was estimated using TLD-100 thermoluminescent dosemeters. During the examination were also recorded information regarding the time of exposure, radiographic technique used, use of thyroid protectors and lead apron, angle and distance of the cone Locator to the patient's skin. The results showed that the input skin doses ranged from 0.3 mGy to 10mGy. The lead apron was used in 71% of exams while the thyroid shield was only used in 58% of the exams. The exposure times ranged from 0,5s to 1,5s. From the results it can be concluded that the radiological procedures are not optimized and that in some cases the patient dose is high.

  7. 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.

  8. Estimation of doses to patients from ''complex'' conventional X-ray examinations

    International Nuclear Information System (INIS)

    Calzado, A.; Vano, E.; Moran, P.; Ruiz, S.; Gonzalez, L.; Castellote, C.

    1991-01-01

    A numerical method has been developed to estimate organ doses and effective dose-equivalent for patients undergoing three 'complex' examinations (barium meal, barium enema and intravenous urography). The separation of radiological procedures into a set of standard numerical views is based on the use of Monte Carlo conversion factors and measurements within a Remab phantom. Radiation doses measured in a phantom for such examinations were compared with predictions of the ''numerical'' method. Dosimetric measurements with thermoluminescent dosemeters attached to the patient's skin along with measurements of the dose-area product during the examination have enabled the derivation of organ doses and to estimate effective dose-equivalent. Mean frequency weighted values of dose-area product, energy imparted to the patient, doses to a set of organs and effective dose-equivalent in the area of Madrid are reported. Comparisons of results with those from similar surveys in other countries were made. (author)

  9. Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

    International Nuclear Information System (INIS)

    Poellaenen, R.

    2002-05-01

    than reported previously or convective updraft may have influenced the transport. Models applicable to large particle dispersion in a turbulent atmosphere should be further developed. The health threat from large nuclear fuel particles differs from that of uniform contamination. In contact with human tissue such as skin, a highly active beta-emitting particle may cause a large but localised dose to the tissue, whereas at distances of more than about one centimetre from the source the dose is negligible. Large particles are poorly inhalable because of their size. They may be deposited in the upper airways but are not easily transported deep into the lungs. Instead, deposition onto the surface of skin is of more relevance with respect to acute deterministic health effects. In the present work, skin doses are calculated for particles of different sizes and different types by assuming the particles are deposited on the body surface. The deposition probability as a function of the number concentration of the particles in air is not estimated. The doses are calculated at the nominal depth of the basal cell layer and averaged over a square centimetre of the skin. Calculated doses are compared with the annual skin dose limit for the public (50 mGy at a depth of 0.07 mm and averaged over 1 cm'). After the Chernobyl accident the most active nuclear fuel particles detected in Europe, hundreds of kilometres from the source, would have been able to produce a skin dose exceeding this limit within one hour when deposited onto skin. However, the appearance of deterministic effects necessitates skin contact lasting more than one day. The health hazards of nuclear fuel particles must be taken into account in estimating the consequences of a severe nuclear accident and planning countermeasures to protect the rescue workers and the general public. (orig.)

  10. Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

    Energy Technology Data Exchange (ETDEWEB)

    Poellaenen, R

    2002-05-01

    been higher than reported previously or convective updraft may have influenced the transport. Models applicable to large particle dispersion in a turbulent atmosphere should be further developed. The health threat from large nuclear fuel particles differs from that of uniform contamination. In contact with human tissue such as skin, a highly active beta-emitting particle may cause a large but localised dose to the tissue, whereas at distances of more than about one centimetre from the source the dose is negligible. Large particles are poorly inhalable because of their size. They may be deposited in the upper airways but are not easily transported deep into the lungs. Instead, deposition onto the surface of skin is of more relevance with respect to acute deterministic health effects. In the present work, skin doses are calculated for particles of different sizes and different types by assuming the particles are deposited on the body surface. The deposition probability as a function of the number concentration of the particles in air is not estimated. The doses are calculated at the nominal depth of the basal cell layer and averaged over a square centimetre of the skin. Calculated doses are compared with the annual skin dose limit for the public (50 mGy at a depth of 0.07 mm and averaged over 1 cm'). After the Chernobyl accident the most active nuclear fuel particles detected in Europe, hundreds of kilometres from the source, would have been able to produce a skin dose exceeding this limit within one hour when deposited onto skin. However, the appearance of deterministic effects necessitates skin contact lasting more than one day. The health hazards of nuclear fuel particles must be taken into account in estimating the consequences of a severe nuclear accident and planning countermeasures to protect the rescue workers and the general public. (orig.)

  11. Estimation of effective dose during hysterosalpingography procedures

    International Nuclear Information System (INIS)

    Alzimamil, K.; Babikir, E.; Alkhorayef, M.; Sulieman, A.; Alsafi, K.; Omer, H.

    2014-08-01

    Hysterosalpingography (HSG) is the most frequently used diagnostic tool to evaluate the endometrial cavity and fallopian tube by using conventional x-ray or fluoroscopy. Determination of the patient radiation doses values from x-ray examinations provides useful guidance on where best to concentrate efforts on patient dose reduction in order to optimize the protection of the patients. The aims of this study were to measure the patients entrance surface air kerma doses (ESA K), effective doses and to compare practices between different hospitals in Sudan. ESA K were measured for patient using calibrated thermo luminance dosimeters (TLDs, Gr-200A). Effective doses were estimated using National Radiological Protection Board (NRPB) software. This study was conducted in five radiological departments: Two Teaching Hospitals (A and D), two private hospitals (B and C) and one University Hospital (E). The mean ESD was 20.1 mGy, 28.9 mGy, 13.6 mGy, 58.65 mGy, 35.7, 22.4 and 19.6 mGy for hospitals A,B,C,D, and E), respectively. The mean effective dose was 2.4 mSv, 3.5 mSv, 1.6 mSv, 7.1 mSv and 4.3 mSv in the same order. The study showed wide variations in the ESDs with three of the hospitals having values above the internationally reported values. Number of x-ray images, fluoroscopy time, operator skills x-ray machine type and clinical complexity of the procedures were shown to be major contributors to the variations reported. Results demonstrated the need for standardization of technique throughout the hospital. The results also suggest that there is a need to optimize the procedures. Local DRLs were proposed for the entire procedures. (author)

  12. MO-D-213-04: The Proximity to the Skin of PTV Affects PTV Coverage and Skin Dose for TomoTherapy

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, T; Higgins, P; Watanabe, Y [University of Minnesota, Minneapolis, MN (United States)

    2015-06-15

    Purpose: The proximity to the skin surface of the PTV for the patients with skin disease could be a concern in terms of the PTV coverage and actual surface dose (SD). IMRT optimization algorithms increase the beam intensity close to the skin in order to compensate for lack of scattering material, leading to enhanced SD but potential hot spots. This study aims to investigate the effect of PTV proximity to the skin on planning and measured SD Methods: All measurements were done for 6 MV X-ray beam of Helical TomoTherapy. An anthropomorphic phantom was scanned in a CT simulator in a routine manner with thermoplastic mask immobilization. PTVs were created with varying distances to the skin of 0 mm -(PTV1), 1 mm- (PTV2), 2 mm-(PTV3) and 3 mm-(PTV4). Also, a 5 mm bolus was used with PTV1 (PTV5). All planning constraints were kept the same in all studies (hard constraint: 95% of the prescription dose covered 95% of the PTV). Gafchromic film (EBT3) was placed under the mask on the phantom surface, and the resulting dose was estimated using RIT software. Results: Optimizing the dose using different PTVs lead to average planned target doses of 10.8, 10.3, 10.2, 10.3 and 10.0 Gy, with maximum doses 12.2, 11.2, 11.1, 11.1 and 10.0 Gy for PTV1, PTV2, PTV3, PTV4 and PTV5, respectively. EBT3 measurements indicated a significant decrease of SD with skin distance by 12.7% (PTV1), 21.9% (PTV2), 24.8% (PTV3) and 28.4% (PTV4) comparing to prescription dose. Placement of a 5 mm bolus on the phantom surface resulted in a SD close to prescribed (+0.5%). Conclusion: This work provides a clear demonstration of the relationship between the skin dose and the PTV to the skin distance. The results indicate the necessity of a bolus even for TomoTherapy when high skin dose is required.

  13. MO-D-213-04: The Proximity to the Skin of PTV Affects PTV Coverage and Skin Dose for TomoTherapy

    International Nuclear Information System (INIS)

    Reynolds, T; Higgins, P; Watanabe, Y

    2015-01-01

    Purpose: The proximity to the skin surface of the PTV for the patients with skin disease could be a concern in terms of the PTV coverage and actual surface dose (SD). IMRT optimization algorithms increase the beam intensity close to the skin in order to compensate for lack of scattering material, leading to enhanced SD but potential hot spots. This study aims to investigate the effect of PTV proximity to the skin on planning and measured SD Methods: All measurements were done for 6 MV X-ray beam of Helical TomoTherapy. An anthropomorphic phantom was scanned in a CT simulator in a routine manner with thermoplastic mask immobilization. PTVs were created with varying distances to the skin of 0 mm -(PTV1), 1 mm- (PTV2), 2 mm-(PTV3) and 3 mm-(PTV4). Also, a 5 mm bolus was used with PTV1 (PTV5). All planning constraints were kept the same in all studies (hard constraint: 95% of the prescription dose covered 95% of the PTV). Gafchromic film (EBT3) was placed under the mask on the phantom surface, and the resulting dose was estimated using RIT software. Results: Optimizing the dose using different PTVs lead to average planned target doses of 10.8, 10.3, 10.2, 10.3 and 10.0 Gy, with maximum doses 12.2, 11.2, 11.1, 11.1 and 10.0 Gy for PTV1, PTV2, PTV3, PTV4 and PTV5, respectively. EBT3 measurements indicated a significant decrease of SD with skin distance by 12.7% (PTV1), 21.9% (PTV2), 24.8% (PTV3) and 28.4% (PTV4) comparing to prescription dose. Placement of a 5 mm bolus on the phantom surface resulted in a SD close to prescribed (+0.5%). Conclusion: This work provides a clear demonstration of the relationship between the skin dose and the PTV to the skin distance. The results indicate the necessity of a bolus even for TomoTherapy when high skin dose is required

  14. Late occurring lesions in the skin of rats after repeated doses of X-rays

    International Nuclear Information System (INIS)

    Hopewell, J.W.

    1985-01-01

    Late radiation damage, characterized by atrophy and necrosis in the skin and subcutaneous tissues, has been demonstrated in both the tail and feet of rats. The incidence of necrosis increased with total dose. These total doses, in the range 72-144 Gy, were given as 4-8 treatment of 18 Gy, each dose separated from the next by an interval of 28 days. This treatment protocol minimized acute epithelial skin reactions. The same regime applied to the skin on the back of rats resulted in a very severe acute reaction occurring after the second to fifth dose of 18 Gy. This was surprising since back skin, like tail skin, is less sensitive to large single doses of radiation than that of the foot. The late radiation reaction in the foot and tail of rats are compared and contrasted with other attempts to assess late effects in rodent skin and with late changes seen in pig skin. (author)

  15. Improved dose estimates for nuclear criticality accidents

    International Nuclear Information System (INIS)

    Wilkinson, A.D.; Basoglu, B.; Bentley, C.L.; Dunn, M.E.; Plaster, M.J.; Dodds, H.L.; Yamamoto, T.

    1995-01-01

    Slide rules are improved for estimating doses and dose rates resulting from nuclear criticality accidents. The original slide rules were created for highly enriched uranium solutions and metals using hand calculations along with the decades old Way-Wigner radioactive decay relationship and the inverse square law. This work uses state-of-the-art methods and better data to improve the original slide rules and also to extend the slide rule concept to three additional systems; i.e., highly enriched (93.2 wt%) uranium damp (H/ 235 U = 10) powder (U 3 O 8 ) and low-enriched (5 wt%) uranium mixtures (UO 2 F 2 ) with a H/ 235 U ratio of 200 and 500. Although the improved slide rules differ only slightly from the original slide rules, the improved slide rules and also the new slide rules can be used with greater confidence since they are based on more rigorous methods and better nuclear data

  16. Survey on patient doses in cardiology in Latin America. Criteria for high skin doses follow up

    International Nuclear Information System (INIS)

    Duran, Ariel; Duro, Ivanna; Lopez, Leonardo; Ramirez, Alfredo; Herrera, Carlos; Navarro, Joaquin; Rivarola, Carlos; Lopez, Jose A.

    2008-01-01

    Full text: As part of the International Action Plan for Protection of Patients and supporting by the IAEA, a survey on patient doses in fluoroscopy guided procedures in cardiology in Latin America has been conducted since 2006. One of the objectives of the survey was to set criteria for the identification and evaluation of high skin doses in a certain number of patients to recommend a clinical follow up for potential radiation injuries (more than 3 Gy at the skin). The used methodology for the survey was initiated with two dedicated workshops held in Santiago de Chile (2005) and San Jose de Costa Rica (2007) involving relevant cardiologists from 15 different Latin American Countries. Some sessions were also attended by experts from the Regulatory and Health Authorities. Standardized forms to collect demographic and patient dosimetric data were agreed. Considering that most of the involved centres had still not dosimeters installed in the cardiology x-ray systems, it was agreed to collect data on fluoroscopy time and total number of cine frames per procedure. Relevant factors influencing radio sensitivity of the skin were also collected. Data from 10 countries representing a sample of 709 patients were received during the first year. Procedures included were diagnostic (DG) (coronary angiography and electrophysiology studies), therapeutic (TH) (percutaneous transluminal coronary angioplasties, cardiac ablations and valvuloplasties) or including both DG and TH. A total of 26 patients (3.7%) were selected for potential high skin doses. Initial considered criteria for selection were more than 30 minutes of fluoroscopy, more than 3,000 cine frames per procedure or patients with more than 100 kg of weight. Maximum reported values were 72 minutes and 8,100 frames. In addition, 5 of these patients were diabetic, 6 have previous fluoroscopy procedures and 5 were over 95 kg. The percentage of selected cases for clinical follow up derived from potential skin injuries seem

  17. Determination of skin dose reduction by lead equivalent gloves

    International Nuclear Information System (INIS)

    Norriza Mohd Isa; Abd Aziz Mhd Ramli

    2006-01-01

    Radiation protective gloves are always used in medical facilities to protect radiation workers from unnecessary radiation exposure. A study on radiation protection gloves which are produced by local company had been performed by the Medical Physics Group, MINT. The gloves were made of lead equivalent material, as the attenuating element. The gloves were evaluated in term of the percentage of skin dose reduction by using a newly developed procedure and facilities in MINT. Attenuation measurements of the gloves had been carried out using direct beams and scattered radiations of different qualities. TLD rings were fitted on finger phantom; and water phantom were used in the measurement. The result were obtained and analysed based on data supplied by manufacturer. (Author)

  18. Recommendations for determining the surface contamination of the skin and estimating radiation exposure of the skin after contamination

    International Nuclear Information System (INIS)

    1989-01-01

    The recommendations are applicable to the determination of surface contaminations of the skin and to the estimation of the expected radiation exposure of the skin of contaminated persons. According to the present recommendations, the radiation exposure can only be estimated for the intact and healthy skin

  19. Guideline values for skin decontamination measures based on nuclidspecific dose equivalent rate factors

    International Nuclear Information System (INIS)

    Pfob, H.; Heinemann, G.

    1992-01-01

    Corresponding dose equivalent rate factors for various radionuclides are now available for determining the skin dose caused by skin contamination. These dose equivalent rate factors take into account all contributions from the types of radiation emitted. Any limits for skin decontamination measures are nowhere contained or determined yet. However, radiological protection does in practice require at least guideline values in order to prevent unsuitable or detrimental measures that can be noticed quite often. New calculations of dose equivalent rate factors for the skin now make the recommendation of guideline values possible. (author)

  20. Characterization of differences in calculated and actual measured skin doses to canine limbs during stereotactic radiosurgery using Gafchromic film

    Energy Technology Data Exchange (ETDEWEB)

    Walters, Jerri [Duke Energy, York, SC (United States); Colorado State University, Fort Collins, CO (United States); Ryan, Stewart [Animal Cancer Center, Colorado State University, Fort Collins, CO (United States); Harmon, Joseph F., E-mail: joseph_harmon@bshsi.org [Bon Secours Cancer Institute, Henrico, VA (United States)

    2012-07-01

    Accurate calculation of absorbed dose to the skin, especially the superficial and radiosensitive basal cell layer, is difficult for many reasons including, but not limited to, the build-up effect of megavoltage photons, tangential beam effects, mixed energy scatter from support devices, and dose interpolation caused by a finite resolution calculation matrix. Stereotactic body radiotherapy (SBRT) has been developed as an alternative limb salvage treatment option at Colorado State University Veterinary Teaching Hospital for dogs with extremity bone tumors. Optimal dose delivery to the tumor during SBRT treatment can be limited by uncertainty in skin dose calculation. The aim of this study was to characterize the difference between measured and calculated radiation dose by the Varian Eclipse (Varian Medical Systems, Palo Alto, CA) AAA treatment planning algorithm (for 1-mm, 2-mm, and 5-mm calculation voxel dimensions) as a function of distance from the skin surface. The study used Gafchromic EBT film (International Specialty Products, Wayne, NJ), FilmQA analysis software, a limb phantom constructed from plastic water Trade-Mark-Sign (fluke Biomedical, Everett, WA) and a canine cadaver forelimb. The limb phantom was exposed to 6-MV treatments consisting of a single-beam, a pair of parallel opposed beams, and a 7-beam coplanar treatment plan. The canine forelimb was exposed to the 7-beam coplanar plan. Radiation dose to the forelimb skin at the surface and at depths of 1.65 mm and 1.35 mm below the skin surface were also measured with the Gafchromic film. The calculation algorithm estimated the dose well at depths beyond buildup for all calculation voxel sizes. The calculation algorithm underestimated the dose in portions of the buildup region of tissue for all comparisons, with the most significant differences observed in the 5-mm calculation voxel and the least difference in the 1-mm voxel. Results indicate a significant difference between measured and calculated data

  1. Evaluation of Skin Dose and Image Quality on Cone Beam Computed Tomography

    International Nuclear Information System (INIS)

    Ahn, Jong Ho; Hong, Chae Seon; Kim, Jin Man; Jang, Jun Young

    2008-01-01

    Cone-beam CT using linear accelerator attached to on-board imager is a image guided therapy equipment. Because it is to check the patient's set-up error, correction, organ and target movement. But imaging dose should be cause of the secondary cancer when taking a image. The aim of this study is investigation of appropriate cone beam CT scan mode to compare and estimate the image quality and skin dose. Measurement by Thermoluminescence dosimeter (TLD-100, Harshaw) with using the Rando phantom are placed on each eight sites in separately H and N, thoracic, abdominal section. each 4 methods of scan modes of are measured the for skin dose in three time. Subsequently, obtained average value. Following image quality QA protocol of equipment manufacturers using the catphan 504 phantom, image quality of each scan mode is compared and analyzed. The results of the measured skin dose are described in here. The skin dose of Head and Neck are measured mode A: 8.96 cGy, mode B: 4.59 cGy, mode C: 3.46 cGy mode D: 1.76 cGy and thoracic mode A: 9.42 cGy, mode B: 4.58 cGy, mode C: 3.65 cGy, mode D: 1.85 cGy, and abdominal mode A: 9.97 cGy, mode B: 5.12 cGy, mode C: 4.03 cGy, mode D: 2.21 cGy. Approximately, dose of mode B are reduced 50%, mode C are reduced 60%, mode D are reduced 80% a point of reference dose of mode A. the results of analyzed HU reproducibility, low contrast resolution, spatial resolution (high contrast resolution), HU uniformity in evaluation item of image quality are within the tolerance value by recommended equipment manufacturer in all scan mode. Maintaining the image quality as well as reducing the image dose are very important in cone beam CT. In the result of this study, we are considered when to take mode A when interested in soft tissue. And we are considered to take mode D when interested in bone scan and we are considered to take mode B, C when standard scan. Increasing secondary cancer risk due to cone beam CT scan should be reduced by low m

  2. Measurement and comparison of skin dose using OneDose MOSFET and Mobile MOSFET for patients with acute lymphoblastic leukemia.

    Science.gov (United States)

    Mattar, Essam H; Hammad, Lina F; Al-Mohammed, Huda I

    2011-07-01

    Total body irradiation is a protocol used to treat acute lymphoblastic leukemia in patients prior to bone marrow transplant. It is involved in the treatment of the whole body using a large radiation field with extended source-skin distance. Therefore measuring and monitoring the skin dose during the treatment is important. Two kinds of metal oxide semiconductor field effect transistor (OneDose MOSFET and mobile MOSEFT) dosimeter are used during the treatment delivery to measure the skin dose to specific points and compare it with the target prescribed dose. The objective of this study was to compare the variation of skin dose in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using OneDose MOSFET detectors and Mobile MOSFET, and then compare both results with the target prescribed dose. The measurements involved 32 patient's (16 males, 16 females), aged between 14-30 years, with an average age of 22.41 years. One-Dose MOSFET and Mobile MOSFET dosimetry were performed at 10 different anatomical sites on every patient. The results showed there was no variation between skin dose measured with OneDose MOSFET and Mobile MOSFET in all patients. Furthermore, the results showed for every anatomical site selected there was no significant difference in the dose delivered using either OneDose MOSFET detector or Mobile MOSFET as compared to the prescribed dose. The study concludes that One-Dose MOSFET detectors and Mobile MOSFET both give a direct read-out immediately after the treatment; therefore both detectors are suitable options when measuring skin dose for total body irradiation treatment.

  3. The effect of low dose ionizing radiation on homeostasis and functional integrity in an organotypic human skin model

    Energy Technology Data Exchange (ETDEWEB)

    Neubeck, Claere von [German Cancer Consortium DKTK partner site Dresden, OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden (Germany); German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Geniza, Matthew J. [Molecular and Cellular Biology Program, Oregon State University, Corvallis OR 97331 (United States); Kauer, Paula M.; Robinson, R. Joe; Chrisler, William B. [Health Impacts and Exposure Science, Pacific Northwest National Laboratory, Richland WA 99352 (United States); Sowa, Marianne B., E-mail: marianne.sowa@pnnl.gov [Health Impacts and Exposure Science, Pacific Northwest National Laboratory, Richland WA 99352 (United States)

    2015-05-15

    Highlights: • Low doses of high LET radiation influence skin homeostasis. • Effects on proliferation and differentiation profiles are LET dependent. • Skin barrier function is not compromised following low dose exposure. - Abstract: Outside the protection of Earth's atmosphere, astronauts are exposed to low doses of high linear energy transfer (LET) radiation. Future NASA plans for deep space missions or a permanent settlement on the moon are limited by the health risks associated with space radiation exposures. There is a paucity of direct epidemiological data for low dose exposures to space radiation-relevant high LET ions. Health risk models are used to estimate the risk for such exposures, though these models are based on high dose experiments. There is increasing evidence, however, that low and high dose exposures result in different signaling events at the molecular level, and may involve different response mechanisms. Further, despite their low abundance, high LET particles have been identified as the major contributor to health risk during manned space flight. The human skin is exposed in every external radiation scenario, making it an ideal epithelial tissue model in which to study radiation induced effects. Here, we exposed an in vitro three dimensional (3-D) human organotypic skin tissue model to low doses of high LET oxygen (O), silicon (Si) and iron (Fe) ions. We measured proliferation and differentiation profiles in the skin tissue and examined the integrity of the skin's barrier function. We discuss the role of secondary particles in changing the proportion of cells receiving a radiation dose, emphasizing the possible impact on radiation-induced health issues in astronauts.

  4. Measurement of off-axis and peripheral skin dose using radiochromic film

    International Nuclear Information System (INIS)

    Butson, Martin J.; Yu, P.K.N.; Metcalfe, P.E.

    1998-01-01

    A radiotherapy skin dose profile can be obtained with radiochromic film. The central axis skin dose relative to D max for a 10x10cm 2 field size was found to be 22%, 17% and 15.5% for 6 MV, 10 MV and 18 MV photon beams. Peripheral dose increased with increasing field size. At 10 MV the skin dose 2 cm outside the geometric field edge was measured as 6%, 10% and 17% for 10x10cm 2 , 20x20cm 2 and 30x30cm 2 field sizes respectively. Off-axis skin dose decreased as distance increased from central axis for fields with Perspex block trays. For a 20x20cm 2 field, an approximately 5-8% drop in percentage skin dose was observed from central axis to the beam edge. (author)

  5. Technical specification of the NRPB thermoluminescent dosemeter used for the measurement of body dose and skin dose

    CERN Document Server

    Shaw, K B

    1977-01-01

    This report specifies the NRPB thermoluminescent dosemeter used for the measurement of radiation dose in tissue at a depth of 700 mg cm sup - sup 2 (body dose) and at a depth of 5-10 mg cm sup - sup 2 (skin dose).

  6. Evaluation of entrance skin dose to the skull in diagnostic radiology

    International Nuclear Information System (INIS)

    Mohamed, Anas Ali Elbushari

    2015-12-01

    Diagnostic x-ray radiology is a common diagnostic practice.Despite of its increasing hazard to human beings, imaging procedures should be achieved with less radiation dose and sufficient image quality. The aim of this study was to estimate the entrance skin dose(ESD) for patients undergoing selected diagnostic x-ray examinations in four hospitals.The study included the examinations of the skull; posterior- anterior(PA) and lateral projections. Fifty patients were enrolled in this study. ESDs were estimated from patients specific exposure parameters using established relation between output (μGy/mAs) and tube voltage(kVp). The estimated ESDs ranged from 0.0097-0.1846 mGy for skull (PA), 0.0097-0.1399 mGy for skull (LAT). These values were acceptable as compared with the international reference dose levels. This study provides additional data that can help the regulatory authority to establish reference dose levels for diagnostic radiology in Sudan.(Author)

  7. Evaluation of skin entrance dose imparted on pediatric patients by thorax exams

    International Nuclear Information System (INIS)

    Oliveira, Mercia L.; Khoury, Helen; Drexler, Guenter; GSF-National Research Center for Environment and Health, Neuherberg; Barros, Edison

    2001-01-01

    In this work the results of a survey of skin entrance dose imparted on pediatric patients are present. Positioning the thermo luminescence dosimeters in contact with the patient's skin, in the center of the incident X-ray beam, collected the skin entrance dose data. The patients were grouped in five age groups: infants, 1,1 to 4 years, 4,1 to 6 years, 6,1 to 10 years and older than 10 years. The results show that the average of skin entrance doses is very higher as compared to the European Community Commission reference levels and to other values found in literature. (author)

  8. Dose-response relationships and threshold levels in skin and respiratory allergy

    NARCIS (Netherlands)

    Arts, J.H.E.; Mommers, C.; Heer, C.de

    2006-01-01

    A literature study was performed to evaluate dose-response relationships and no-effect levels for sensitization and elicitation in skin- and respiratory allergy. With respect to the skin, dose-response relationships and no-effect levels were found for both intradermal and topical induction, as well

  9. Confocal laser scanning microscopy to estimate nanoparticles’ human skin penetration in vitro

    Directory of Open Access Journals (Sweden)

    Zou Y

    2017-10-01

    Full Text Available Ying Zou,1,2,* Anna Celli,2,3,* Hanjiang Zhu,2,* Akram Elmahdy,2 Yachao Cao,2 Xiaoying Hui,2 Howard Maibach2 1Skin & Cosmetic Research Department, Shanghai Skin Disease Hospital, Shanghai, People’s Republic of China; 2Department of Dermatology, School of Medicine, University of California San Francisco, San Francisco, CA, USA; 3San Francisco Veterans Medical Center, San Francisco, CA, USA *These authors contributed equally to this work Objective: With rapid development of nanotechnology, there is increasing interest in nanoparticle (NP application and its safety and efficacy on human skin. In this study, we utilized confocal laser scanning microscopy to estimate NP skin penetration.Methods: Three different-sized polystyrene NPs marked with red fluorescence were applied to human skin, and Calcium Green 5N was used as a counterstain. Dimethyl sulfoxide (DMSO and ethanol were used as alternative vehicles for NPs. Tape stripping was utilized as a barrier-damaged skin model. Skin biopsies dosed with NPs were incubated at 4°C or 37°C for 24 hours and imaged using confocal laser scanning microscopy.Results: NPs were localized in the stratum corneum (SC and hair follicles without penetrating the epidermis/dermis. Barrier alteration with tape stripping and change in incubation temperature did not induce deeper penetration. DMSO enhanced NP SC penetration but ethanol did not.Conclusion: Except with DMSO vehicle, these hydrolyzed polystyrene NPs did not penetrate intact or barrier-damaged human “viable” epidermis. For further clinical relevance, in vivo human skin studies and more sensitive analytic chemical methodology are suggested. Keywords: nanoparticles, skin penetration, stratum corneum, confocal laser scanning microscopy, tape stripping

  10. Confocal laser scanning microscopy to estimate nanoparticles' human skin penetration in vitro.

    Science.gov (United States)

    Zou, Ying; Celli, Anna; Zhu, Hanjiang; Elmahdy, Akram; Cao, Yachao; Hui, Xiaoying; Maibach, Howard

    2017-01-01

    With rapid development of nanotechnology, there is increasing interest in nanoparticle (NP) application and its safety and efficacy on human skin. In this study, we utilized confocal laser scanning microscopy to estimate NP skin penetration. Three different-sized polystyrene NPs marked with red fluorescence were applied to human skin, and Calcium Green 5N was used as a counterstain. Dimethyl sulfoxide (DMSO) and ethanol were used as alternative vehicles for NPs. Tape stripping was utilized as a barrier-damaged skin model. Skin biopsies dosed with NPs were incubated at 4°C or 37°C for 24 hours and imaged using confocal laser scanning microscopy. NPs were localized in the stratum corneum (SC) and hair follicles without penetrating the epidermis/dermis. Barrier alteration with tape stripping and change in incubation temperature did not induce deeper penetration. DMSO enhanced NP SC penetration but ethanol did not. Except with DMSO vehicle, these hydrolyzed polystyrene NPs did not penetrate intact or barrier-damaged human "viable" epidermis. For further clinical relevance, in vivo human skin studies and more sensitive analytic chemical methodology are suggested.

  11. Confocal laser scanning microscopy to estimate nanoparticles’ human skin penetration in vitro

    Science.gov (United States)

    Elmahdy, Akram; Cao, Yachao; Hui, Xiaoying; Maibach, Howard

    2017-01-01

    Objective With rapid development of nanotechnology, there is increasing interest in nanoparticle (NP) application and its safety and efficacy on human skin. In this study, we utilized confocal laser scanning microscopy to estimate NP skin penetration. Methods Three different-sized polystyrene NPs marked with red fluorescence were applied to human skin, and Calcium Green 5N was used as a counterstain. Dimethyl sulfoxide (DMSO) and ethanol were used as alternative vehicles for NPs. Tape stripping was utilized as a barrier-damaged skin model. Skin biopsies dosed with NPs were incubated at 4°C or 37°C for 24 hours and imaged using confocal laser scanning microscopy. Results NPs were localized in the stratum corneum (SC) and hair follicles without penetrating the epidermis/dermis. Barrier alteration with tape stripping and change in incubation temperature did not induce deeper penetration. DMSO enhanced NP SC penetration but ethanol did not. Conclusion Except with DMSO vehicle, these hydrolyzed polystyrene NPs did not penetrate intact or barrier-damaged human “viable” epidermis. For further clinical relevance, in vivo human skin studies and more sensitive analytic chemical methodology are suggested. PMID:29184403

  12. A Monte Carlo estimation of effective dose in chest tomosynthesis

    International Nuclear Information System (INIS)

    Sabol, John M.

    2009-01-01

    calculated to be 0.124 mSv (ICRP60) [0.134 mSv (ICRP103)]. This is less than 75% of that predicted by scaling of the PA mA s ratio. This lower dose was due to changes in the focal-spot-to-skin distance, effective changes in collimation with projection angle, rounding down of the mA s step, and variations in organ exposure to the primary x-ray beam for each view. Large errors in dose estimation can occur if these factors are not accurately modeled. Conclusions: The effective dose of a chest examination with this chest tomosynthesis system is about twice that of a two-view chest examination and less than 2% of the published average values for thoracic CT. It is shown that complete consideration of the tomosynthesis acquisition technique and geometry is required for accurate determination of the effective dose to the patient. Tomosynthesis provides three-dimensional imaging at a dose level comparable to a two-view chest x-ray examination and may provide a low dose alternative to thoracic CT for obtaining depth information in chest imaging.

  13. Validation of radiation dose estimations in VRdose: comparing estimated radiation doses with observed radiation doses

    International Nuclear Information System (INIS)

    Nystad, Espen; Sebok, Angelia; Meyer, Geir

    2004-04-01

    The Halden Virtual Reality Centre has developed work-planning software that predicts the radiation exposure of workers in contaminated areas. To validate the accuracy of the predicted radiation dosages, it is necessary to compare predicted doses to actual dosages. During an experimental study conducted at the Halden Boiling Water Reactor (HBWR) hall, the radiation exposure was measured for all participants throughout the test session, ref. HWR-681 [3]. Data from this experimental study have also been used to model tasks in the work-planning software and gather data for predicted radiation exposure. Two different methods were used to predict radiation dosages; one method used all radiation data from all the floor levels in the HBWR (all-data method). The other used only data from the floor level where the task was conducted (isolated data method). The study showed that the all-data method gave predictions that were on average 2.3 times higher than the actual radiation dosages. The isolated-data method gave predictions on average 0.9 times the actual dosages. (Author)

  14. Estimation of population dose from all sources in Japan

    International Nuclear Information System (INIS)

    Kusama, Tomoko; Nakagawa, Takeo; Kai, Michiaki; Yoshizawa, Yasuo

    1988-01-01

    The purposes of estimation of population doses are to understand the per-caput doses of the public member from each artificial radiation source and to determine the proportion contributed of the doses from each individual source to the total irradiated population. We divided the population doses into two categories: individual-related and source-related population doses. The individual-related population dose is estimated based on the maximum assumption for use in allocation of the dose limits for members of the public. The source-related population dose is estimated both to justify the sources and practices and to optimize radiation protection. The source-related population dose, therefore, should be estimated as realistically as possible. We investigated all sources that caused exposure to the population in Japan from the above points of view

  15. Minimal erythema dose and minimal melanogenesis dose relate better to objectively measured skin type than to Fitzpatricks skin type

    DEFF Research Database (Denmark)

    Wulf, Hans Christian; Philipsen, Peter A; Ravnbak, Mette H

    2010-01-01

    Fitzpatrick skin type (FST I-IV) is a subjective expression of ultraviolet (UV) sensitivity based on erythema and tanning reactivity after a single exposure. Pigment protection factor (PPF) is an objective measurement of skin sensitivity in all skin types after a single exposure....

  16. Estimation of effective dose from radionuclides contained in misch metal

    International Nuclear Information System (INIS)

    Furuta, Etsuko; Aburai, Tamaru; Nisizawa, Kunihide

    2003-01-01

    Radionuclides contained in three kinds of misch metal products and two kinds of ingots were analyzed using a Ge (Li) semiconductor detector. Lanthanum-138 ( 138 La) and several daughter nuclides derived from thorium and uranium series were detected in all samples. All misch metal products and ingots were determined to be radioactive consumer products (RCP), although they have not been regarded as RCP in Japan. 138 La showed the highest nuclide content rate of all the radionuclides, and the lanthanum metal ingots displayed the highest specific activity at 720 mBq·g -1 . The maximum external effective dose was estimated to be at 3.7 mSv when a metal match was carried for 8,760 hours at 1 mm from the skin. The calculated effective dose under some conditions exceeded 10 μSv per year. This value corresponded to the exemption standard proposed by the UK's National Radiological Protection Board. Individuals working with large amounts of RCP should be appropriately protected. (author)

  17. Monte Carlo skin dose simulation in intraoperative radiotherapy of breast cancer using spherical applicators

    Science.gov (United States)

    Moradi, F.; Ung, N. M.; Khandaker, M. U.; Mahdiraji, G. A.; Saad, M.; Malik, R. Abdul; Bustam, A. Z.; Zaili, Z.; Bradley, D. A.

    2017-08-01

    The relatively new treatment modality electronic intraoperative radiotherapy (IORT) is gaining popularity, irradiation being obtained within a surgically produced cavity being delivered via a low-energy x-ray source and spherical applicators, primarily for early stage breast cancer. Due to the spatially dramatic dose-rate fall off with radial distance from the source and effects related to changes in the beam quality of the low keV photon spectra, dosimetric account of the Intrabeam system is rather complex. Skin dose monitoring in IORT is important due to the high dose prescription per treatment fraction. In this study, modeling of the x-ray source and related applicators were performed using the Monte Carlo N-Particle transport code. The dosimetric characteristics of the model were validated against measured data obtained using an ionization chamber and EBT3 film as dosimeters. By using a simulated breast phantom, absorbed doses to the skin for different combinations of applicator size (1.5-5 cm) and treatment depth (0.5-3 cm) were calculated. Simulation results showed overdosing of the skin (>30% of prescribed dose) at a treatment depth of 0.5 cm using applicator sizes larger than 1.5 cm. Skin doses were significantly increased with applicator size, insofar as delivering 12 Gy (60% of the prescribed dose) to skin for the largest sized applicator (5 cm diameter) and treatment depth of 0.5 cm. It is concluded that the recommended 0.5-1 cm distance between the skin and applicator surface does not guarantee skin safety and skin dose is generally more significant in cases with the larger applicators. Highlights: • Intrabeam x-ray source and spherical applicators were simulated and skin dose was calculated. • Skin dose for constant skin to applicator distance strongly depends on applicator size. • Use of larger applicators generally results in higher skin dose. • The recommended 0.5-1 cm skin to applicator distance does not guarantee skin

  18. Technical basis for beta skin dose calculations at the Y-12 Plant

    International Nuclear Information System (INIS)

    Thomas, J.M.; Bogard, R.S.

    1994-03-01

    This report describes the methods for determining shallow dose equivalent to workers at the Oak Ridge Y-12 Plant from skin contamination detected by survey instrumentation. Included is a discussion of how the computer code VARSKIN is used to calculate beta skin dose and how the code input parameters affect skin dose calculation results. A summary of Y-12 Plant specific assumptions used in performing VARSKIN calculations is presented. Derivations of contamination levels that trigger the need for skin dose assessment are given for both enriched and depleted uranium with the use of Y-12 Plant site-specific survey instruments. Department of Energy recording requirements for nonuniform exposure of the skin are illustrated with sample calculations

  19. WE-E-18A-03: How Accurately Can the Peak Skin Dose in Fluoroscopy Be Determined Using Indirect Dose Metrics?

    International Nuclear Information System (INIS)

    Jones, A; Pasciak, A

    2014-01-01

    Purpose: Skin dosimetry is important for fluoroscopically-guided interventions, as peak skin doses (PSD) that Result in skin reactions can be reached during these procedures. The purpose of this study was to assess the accuracy of different indirect dose estimates and to determine if PSD can be calculated within ±50% for embolization procedures. Methods: PSD were measured directly using radiochromic film for 41 consecutive embolization procedures. Indirect dose metrics from procedures were collected, including reference air kerma (RAK). Four different estimates of PSD were calculated and compared along with RAK to the measured PSD. The indirect estimates included a standard method, use of detailed information from the RDSR, and two simplified calculation methods. Indirect dosimetry was compared with direct measurements, including an analysis of uncertainty associated with film dosimetry. Factors affecting the accuracy of the indirect estimates were examined. Results: PSD calculated with the standard calculation method were within ±50% for all 41 procedures. This was also true for a simplified method using a single source-to-patient distance (SPD) for all calculations. RAK was within ±50% for all but one procedure. Cases for which RAK or calculated PSD exhibited large differences from the measured PSD were analyzed, and two causative factors were identified: ‘extreme’ SPD and large contributions to RAK from rotational angiography or runs acquired at large gantry angles. When calculated uncertainty limits [−12.8%, 10%] were applied to directly measured PSD, most indirect PSD estimates remained within ±50% of the measured PSD. Conclusions: Using indirect dose metrics, PSD can be determined within ±50% for embolization procedures, and usually to within ±35%. RAK can be used without modification to set notification limits and substantial radiation dose levels. These results can be extended to similar procedures, including vascular and interventional oncology

  20. Dosimetry in Interventional Radiology - Effective Dose Estimation

    International Nuclear Information System (INIS)

    Miljanic, S.; Buls, N.; Clerinx, P.; Jarvinen, H.; Nikodemova, D.; Ranogajec-Komor, M; D'Errico, F.

    2008-01-01

    Interventional radiological procedures can lead to significant radiation doses to patients and to staff members. In order to evaluate the personal doses with respect to the regulatory dose limits, doses measured by dosimeters have to be converted to effective doses (E). Measurement of personal dose equivalent Hp(10) using a single unshielded dosimeter above the lead apron can lead to significant overestimation of the effective dose, while the measurement with dosimeter under the apron can lead to underestimation. To improve the accuracy, measurements with two dosimeters, one above and the other under the apron have been suggested ( d ouble dosimetry ) . The ICRP has recommended that interventional radiology departments develop a policy that staff should wear two dosimeters. The aim of this study was to review the double dosimetry algorithms for the calculation of effective dose in high dose interventional radiology procedures. The results will be used to develop general guidelines for personal dosimetry in interventional radiology procedures. This work has been carried out by Working Group 9 (Radiation protection dosimetry of medical staff) of the CONRAD project, which is a Coordination Action supported by the European Commission within its 6th Framework Program.(author)

  1. Skin and gonadal dose reduction during hip radiography of the bull

    International Nuclear Information System (INIS)

    Wood, A.K.W.; Blockey, deB.; Reynolds, K.M.; Leith, I.S.; Burns, P.A.

    1979-01-01

    Radiology is being used to an increasing extent in the clinical diagnosis of hip lameness in bulls. Consequent gonadal doses may have important implications in later breeding programmes. Skin and gonadal doses were recorded during hip radiography of 18 bulls. An additional 0.13 mm copper filtration reduced skin dose by more than one third, but had no effect on gonadal dose. The average radiation dose to the gonads was approximately halved by completely surrounding the scrotum with lead sheeting 0.95 mm in thickness. (author)

  2. Comparison of Adsorbed Skin Dose Received by Patients in Cone Beam Computed Tomography, Spiral and Conventional Computed Tomography Scanninng

    Directory of Open Access Journals (Sweden)

    Rahimi A

    2011-12-01

    Full Text Available Background and Aims: The evaluation of absorbed dose received by patients could give useful information for radiation risk estimation. This study was performed to compare the entrance skin dose received by patients in cone beam computed tomography (CBCT, conventional and spiral computed tomography (CT.Materials and Methods: In this experimental study, 81 calibrated TLD chips were used. the TLD chips were placed on facial, thyroid and end of sternum skin surface in patients referred for CT of the paranasal sinuses(3 TLD chips for each area to estimate the absorbed dose received by central part of radiation field, thyroid and out of field areas, respectively. The data were analyzed using one-way ANOVA and Tukey tests. Results: The dose delivered to the center of irradiated field was about 0.79±0.09 mGy in CBCT technique compared with 16.31±3.71 and 18.84±4.12 mGy for spiral and conventional CT, respectively. The received dose by the out of field areas was about 54 percent of central area dose. There was statistical significant relationship between the imaging modalities and absorbed dose received by patients (P=0.016. The least absorbed dose was for CBCT and the greatest dose was for conventional CT imaging technique.Conclusion: The dose delivered to central area of irradiated field in conventional and spiral CT imaging modalities was about 24 times greater than of that in CBCT. Also, the highest received dose was for central area of radiated field and the lowest dose was for the out of field areas.

  3. Estimation of radiation risks at low dose

    International Nuclear Information System (INIS)

    1990-04-01

    The report presents a review of the effects caused by radiation in low doses, or at low dose rates. For the inheritable (or ''genetic''), as well as for the cancer producing effects of radiation, present evidence is consistent with: (a) a non-linear relationship between the frequency of at least some forms of these effects, with comparing frequencies caused by doses many times those received annually from natural sources, with those caused by lower doses; (b) a probably linear relationship, however, between dose and frequency of effects for dose rates in the region of that received from natural sources, or at several times this rate; (c) no evidence to indicate the existence of a threshold dose below which such effects are not produced, and a strong inference from the mode of action of radiation on cells at low dose rates that no such thresholds are likely to apply to the detrimental, cancer-producing or inheritable, effects resulting from unrepaired damage to single cells. 19 refs

  4. Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

    Science.gov (United States)

    Wang, Chu

    Patients undergoing cardiac catheterization are potentially at risk of radiation-induced health effects from the interventional fluoroscopic X-ray imaging used throughout the clinical procedure. The amount of radiation exposure is highly dependent on the complexity of the procedure and the level of optimization in imaging parameters applied by the clinician. For cardiac catheterization, patient radiation dosimetry, for key organs as well as whole-body effective, is challenging due to the lack of fixed imaging protocols, unlike other common X-ray based imaging modalities. Pediatric patients are at a greater risk compared to adults due to their greater cellular radio-sensitivities as well as longer remaining life-expectancy following the radiation exposure. In terms of radiation dosimetry, they are often more challenging due to greater variation in body size, which often triggers a wider range of imaging parameters in modern imaging systems with automatic dose rate modulation. The overall objective of this dissertation was to develop a comprehensive method of radiation dose estimation for pediatric patients undergoing cardiac catheterization. In this dissertation, the research is divided into two main parts: the Physics Component and the Clinical Component. A proof-of-principle study focused on two patient age groups (Newborn and Five-year-old), one popular biplane imaging system, and the clinical practice of two pediatric cardiologists at one large academic medical center. The Physics Component includes experiments relevant to the physical measurement of patient organ dose using high-sensitivity MOSFET dosimeters placed in anthropomorphic pediatric phantoms. First, the three-dimensional angular dependence of MOSFET detectors in scatter medium under fluoroscopic irradiation was characterized. A custom-made spherical scatter phantom was used to measure response variations in three-dimensional angular orientations. The results were to be used as angular dependence

  5. Dose-modifying factors for skin ulceration in mouse legs exposed to gamma rays

    International Nuclear Information System (INIS)

    Masuda, Kouji; Miyoshi, Makoto; Uehara, Satoru; Omagari, Junichi; Withers, H.R.

    1996-01-01

    To assess the dose-modifying factors for skin ulceration, the hind legs of mice were irradiated using gamma-rays of various doses in single exposures. The skin ulceration began to occur 2 months after irradiation, after early skin reactions such as wet desquamation, had healed completely. No new skin ulceration was observed more than 8 months after irradiation even though the observations were continued until 12 months post-irradiation. The ulceration dose 50 (UD50), a dose required to produce skin ulceration in from 2 to 8 months in 50% of the tested animals, was calculated for each treatment schedule. The preliminary shaving procedure reduced the UD50 dose to 0.85 that of the untreated controls. The ventral aspect of the hind leg was more radioresistant to single-dose irradiation than was to the dorsal aspect. The UD50 for the ventral aspect was 1.29 times that for the dorsal aspect when the skin had been previously shaved, and 1.46 times that for the unshaved control legs. The UD50 was 7 and 14% larger when mice were kept in the dorsal rather than the abdominal position during irradiation, for the preliminarily shaved and unshaved skin, respectively. (author)

  6. Direct measurement of a patient's entrance skin dose during pediatric cardiac catheterization

    International Nuclear Information System (INIS)

    Sun, Lue; Mizuno, Yusuke; Goto, Takahisa; Iwamoto, Mari; Koguchi, Yasuhiro; Miyamoto, Yuka; Tsuboi, Koji; Chida, Koichi; Moritake, Takashi

    2014-01-01

    Children with complex congenital heart diseases often require repeated cardiac catheterization; however, children are more radiosensitive than adults. Therefore, radiation-induced carcinogenesis is an important consideration for children who undergo those procedures. We measured entrance skin doses (ESDs) using radio-photoluminescence dosimeter (RPLD) chips during cardiac catheterization for 15 pediatric patients (median age, 1.92 years; males, n = 9; females, n = 6) with cardiac diseases. Four RPLD chips were placed on the patient's posterior and right side of the chest. Correlations between maximum ESD and dose-area products (DAP), total number of frames, total fluoroscopic time, number of cine runs, cumulative dose at the interventional reference point (IRP), body weight, chest thickness, and height were analyzed. The maximum ESD was 80 ± 59 (mean ± standard deviation) mGy. Maximum ESD closely correlated with both DAP (r = 0.78) and cumulative dose at the IRP (r = 0.82). Maximum ESD for coiling and ballooning tended to be higher than that for ablation, balloon atrial septostomy, and diagnostic procedures. In conclusion, we directly measured ESD using RPLD chips and found that maximum ESD could be estimated in real-time using angiographic parameters, such as DAP and cumulative dose at the IRP. Children requiring repeated catheterizations would be exposed to high radiation levels throughout their lives, although treatment influences radiation dose. Therefore, the radiation dose associated with individual cardiac catheterizations should be analyzed, and the effects of radiation throughout the lives of such patients should be followed. (author)

  7. Maximum skin dose assessment in interventional cardiology: large area detectors and calculation methods

    International Nuclear Information System (INIS)

    Quail, E.; Petersol, A.

    2002-01-01

    Advances in imaging technology have facilitated the development of increasingly complex radiological procedures for interventional radiology. Such interventional procedures can involve significant patient exposure, although often represent alternatives to more hazardous surgery or are the sole method for treatment. Interventional radiology is already an established part of mainstream medicine and is likely to expand further with the continuing development and adoption of new procedures. Between all medical exposures, interventional radiology is first of the list of the more expansive radiological practice in terms of effective dose per examination with a mean value of 20 mSv. Currently interventional radiology contribute 4% to the annual collective dose, in spite of contributing to total annual frequency only 0.3% but considering the perspectives of this method can be expected a large expansion of this value. In IR procedures the potential for deterministic effects on the skin is a risk to be taken into account together with stochastic long term risk. Indeed, the International Commission on Radiological Protection (ICRP) in its publication No 85, affirms that the patient dose of priority concern is the absorbed dose in the area of skin that receives the maximum dose during an interventional procedure. For the mentioned reasons, in IR it is important to give to practitioners information on the dose received by the skin of the patient during the procedure. In this paper maximum local skin dose (MSD) is called the absorbed dose in the area of skin receiving the maximum dose during an interventional procedure

  8. Estimation of Skin to Subarachnoid Space Depth: An Observational Study.

    Science.gov (United States)

    Hazarika, Rajib; Choudhury, Dipika; Nath, Sangeeta; Parua, Samit

    2016-10-01

    In a patient, the skin to Subarachnoid Space Depth (SSD) varies considerably at different levels of the spinal cord. It also varies from patient to patient at the same vertebral level as per age, sex and Body Mass Index (BMI). Estimation of the skin to SSD reduces complications related to spinal anaesthesia. To measure the skin to SSD in the Indian population and to find a formula for predicting this depth. Three hundred adult patients belonging to American Society of Anaesthesiologist class I and II, undergoing surgery using spinal anaesthesia in various surgical specialities of Gauhati Medical College were selected by systemic sampling for this prospective, observational study. Patients were divided into three groups: Group M containing male patients, Group F containing non-pregnant female patients, and Group PF containing pregnant female's patients. SSD was measured after performing lumbar puncture. The relationship between SSD and patient characteristics were studied, correlated and statistical analysis was used to find a formula for predicting the skin to SSD. Statistical analysis was done using Statistical Package for Social Sciences (SPSS 21.0, Chicago, IL, USA). One-way ANOVA with post-hoc(Bonferroni correction factor) analysis was applied to compare the three groups. Multivariate analysis was done for the covariates followed by a multivariate regression analysis to evaluate the covariates influencing SSD for each group separately. Mean SSD was 4.37±0.31cm in the overall population. SSD in adult males was 4.49±0.19cm which was significantly longer than that observed in female's 4.18±0.39cm which was comparable with SSD in parturient 4.43±0.19 cm. The formula for predicting the skin to SSD in the male population was 1.718+0.077×BMI+0.632×Height, in nonpregnant female population was 1.828+0.077×BMI+0.018×Height+0.007×Age and 0.748+0.209×BMI+4.703×Height-0.054×weight in parturient females, respectively. Skin to SSD correlated with the BMI in all

  9. Implications of the quadratic cell survival curve and human skin radiation ''tolerance doses'' on fractionation and superfractionation dose selection

    International Nuclear Information System (INIS)

    Douglas, B.G.

    1982-01-01

    An analysis of early published multifraction orthovoltage human acute skin irradiation tolerance isoeffect doses is presented. It indicates that human acute skin radiation reactions may result from the repetition, with each dose fraction, of a cell survival curve of the form: S = e/sup -(αD + βD 2 )/). The analysis also shows no need for an independent proliferation related time factor for skin, for daily treatments of six weeks or less in duration. The value obtained for the constant β/α for orthovoltage irradiation from these data is 2.9 x 10 -3 rad -1 for the cell line determining acute skin tolerance. A radiation isoeffect relationship, based on the quadratic cell survival curve, is introduced for human skin. This relationship has some advantages over the nominal standard dose (NSD). First, its use is not restricted to tolerance level reactions. Second, a modification of the relationship, which is also introduced, may be employed in the selection of doses per treatment when irradiation dose fractions are administered at short intervals where repair of sublethal injury is incomplete

  10. Verification of skin dose according to the location of tumor in Tomotherapy

    International Nuclear Information System (INIS)

    Yoon, Bo Reum; Park, Su Yeon; Park, Byoung Suk; KIm, Jong Sik; Song, Ki Won

    2014-01-01

    To verify the skin dose in Tomotherapy-based radiation treatment according to the change in tumor locations, skin dose was measured by using Gafchromic EBT3 film and compared with the planned doses to find out the gap between them. In this study, to measure the skin dose, I'm RT Phantom(IBA Dosimetry, Germany) was utilized. After obtaining the 2.5 mm CT images, tumor locations and skin dose measuring points were set by using Pinnacle(ver 9.2, Philips Medical System, USA). The tumor location was decided to be 5 mm and 10 mm away from surface of the phantom and center. Considering the attenuation of a Tomo-couch, we ensured a symmetric placement between the ceiling and floor directions of the phantom. The measuring point of skin doses was set to have 3 mm and 5 mm thickness from the surface. Measurement was done 3 times. By employing TomoHD(TomoHD treatment system, Tomotherapy Inc., Madison, Wisconsin, USA), we devised Tomotherapy plans, measured 3 times by inserting Gafchromic EBT3 film into the phantom and compared the measurement with the skin dose treatment plans. The skin doses in the upper part of the phantom, when the tumor was located in the center, were found to be 7.53 cGy and 7.25 cGy in 5 mm and 3 mm respectively. If placed 5 mm away from the skin in the ceiling direction, doses were 18.06 cGy and 16.89 cGy; if 10 mm away, 20.37 cGy and 18.27 cGy, respectively. The skin doses in the lower part of the phantom, when the tumor was located in the center, recorded 8.82 cGy and 8.29 cGy in 5 mm and 3 mm, each; if located 5mm away from the lower part skin, 21.69 cGy and 19.78 cGy were respectively recorded; and if 10 mm away, 20.48 cGy and 19.57 cGy were recorded. If the tumor was placed in the center, skin doses were found to increase by 3.2-17.1% whereas if the tumor is 5 mm away from the ceiling part, the figure decreased to 2.8-9.0%. To the Tomo-couch direction, skin doses showed an average increase of 11% or over, compared to the planned treatment

  11. Estimation of radiation dose in Sakkara area

    International Nuclear Information System (INIS)

    Hussein, A.Z.; Hussein, M.I.; Abd El-Hady, M.L.

    1998-01-01

    Radon levels seem to be relatively high in some deeply seated caves at various sites in Egypt, apparently due to the U and Th contents in the rocks lining the burial places that are situated deep in the ground. The Sakkara area was examined, and a survey of the exposure rates, effective doses, radon daughter concentrations, and annual doses is presented in the tabular form. (P.A.)

  12. Estimation of radiation dose in Sakkara area

    Energy Technology Data Exchange (ETDEWEB)

    Hussein, A Z; Hussein, M I [National Centre for Nuclear Safety and Radiation Control, Atomic Energy Authority, Cairo (Egypt); Abd El-Hady, M L [Physics Department, Faculty of Science, El Minia University, El-Minia (Egypt)

    1999-12-31

    Radon levels seem to be relatively high in some deeply seated caves at various sites in Egypt, apparently due to the U and Th contents in the rocks lining the burial places that are situated deep in the ground. The Sakkara area was examined, and a survey of the exposure rates, effective doses, radon daughter concentrations, and annual doses is presented in the tabular form. (P.A.) 1 tab., 6 refs.

  13. Dose characteristics of total-skin electron-beam irradiation with six-dual electron fields

    International Nuclear Information System (INIS)

    Choi, Tae Jin; Kim, Jin Hee; Kim, Ok Bae

    1998-01-01

    To obtain the uniform dose at limited depth to entire surface of the body, the dose characteristics of degraded electron beam of the large target-skin distance and the dose distribution of the six-dual electron fields were investigated. The experimental dose distributions included the depth dose curve, spatial dose and attenuated electron beam were determined with 300 cm of Target-Skin Distance (TSD) and full collimator size (35x35 cm 2 on TSD 100 cm) in 4 MeV electron beam energy. Actual collimated field size of 105 cmx105 cm at the distance of 300 cm could include entire hemibody. A patient was standing on step board with hands up and holding the pole to stabilize his/her positions for the six-dual fields technique. As a scatter-degrader, 0.5 cm of acrylic plate was inserted at 20 cm from the body surface on the electron beam path to induce ray scattering and to increase the skin dose. The Full Width at Half Maximum(FWHM) of dose profile was 130 cm in large field of 105x105 cm 2 . The width of 100±10% of the resultant dose from two adjacent fields which were separated at 25 cm from field edge for obtaining the dose uniformity was extended to 186 cm. The depth of maximum dose lies at 5 mm and the 80% depth dose lies between 7 and 8 mm for the degraded electron beam by using the 0.5 cm thickness of acrylic absorber. Total skin electron beam irradiation (TSEBI) was carried out using the six dual fields has been developed at Stanford University. The dose distribution in TSEBI showed relatively uniform around the flat region of skin except the protruding and deeply curvatured portion of the body, which showed excess of dose at the former and less dose at the latter. The percent depth dose, profile curves and superimposed dose distribution were investigated using the degraded using the degraded electron beam through the beam absorber. The dose distribution obtained by experiments of TSEBI showed within±10% difference excepts the protruding area of skin which needs a

  14. What is the effect of different skin types on the required dose for photodynamic therapy?

    CSIR Research Space (South Africa)

    Karsten, AE

    2008-11-01

    Full Text Available For effective laser treatment it is very important to provide the correct dose at the required treatment depth. In South Africa we have a richness of ethnic groups contributing to a large variety in skin tones. Effective laser treatment of skin...

  15. Evaluation of the breast plan using the TLD and MOSFET for the skin dose

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Myeong; Kim, Young Bum; Bak, Sang Yun; Lee, Sang Rok; Jeong, Se Young [Dept. of Radiation Oncology, Korea University Ansan Hospital, Ansan (Korea, Republic of)

    2015-12-15

    The measurement of skin dose is very important that treatment of breast cancer. On account of the cold or hot dose as compared with prescription dose, it is necessary to analyse the skin dose occurring during the various plan of the breast cancer treatment. At our hospital, we want to apply various analyses using a diversity of dosimeters to the breast cancer treatment. In the study, the anthropomorphic phantom is used to find out the dose difference of the skin(draining site), scar and others occurring from the tangential treatment plan of breast cancer. We took computed tomography scan of the anthropomorphic phantom and made plans for the treatment planing using open and wedge, Field-in-Field, Dose fluence. Using these, we made a comparative analysis of the dose date points by using the Eclipse. For the dose comparison, we place the anthropomorphic phantom in the treatment room and compared the measurement results by using the TLD and MOSFET on the dose data points. On the central point of treatment planing basis, the upward and downward skin dose measured by the MOSFET was the highest when the fluence was used. The skin dose of inner and outer was distinguished from the figure(5.7% - 10.3%) when the measurements were fulfilled by using TLD and MOSFET. The other side of breast dose was the lowest in the open beam, on the other hand, is highest in the Dose fluence plan. In the different kinds of treatment, the dose deviation of inner and outer was the highest, and so this was the same with the TLD and MOSFET measurement case. The outer deviation was highest in the TLD, and the Inner' was highest in the MOSFET. Skin dose in relation to the treatment plan was the highest in the planing using the fluence technique in general and it was supposed that the high dose had been caused by the movement of the MLC. There's some differences among the all the treatment planning, but the sites such as IM node occurring the lack of dose, scar, drain site are needed pay

  16. Evaluation of the breast plan using the TLD and MOSFET for the skin dose

    International Nuclear Information System (INIS)

    Kim, Seon Myeong; Kim, Young Bum; Bak, Sang Yun; Lee, Sang Rok; Jeong, Se Young

    2015-01-01

    The measurement of skin dose is very important that treatment of breast cancer. On account of the cold or hot dose as compared with prescription dose, it is necessary to analyse the skin dose occurring during the various plan of the breast cancer treatment. At our hospital, we want to apply various analyses using a diversity of dosimeters to the breast cancer treatment. In the study, the anthropomorphic phantom is used to find out the dose difference of the skin(draining site), scar and others occurring from the tangential treatment plan of breast cancer. We took computed tomography scan of the anthropomorphic phantom and made plans for the treatment planing using open and wedge, Field-in-Field, Dose fluence. Using these, we made a comparative analysis of the dose date points by using the Eclipse. For the dose comparison, we place the anthropomorphic phantom in the treatment room and compared the measurement results by using the TLD and MOSFET on the dose data points. On the central point of treatment planing basis, the upward and downward skin dose measured by the MOSFET was the highest when the fluence was used. The skin dose of inner and outer was distinguished from the figure(5.7% - 10.3%) when the measurements were fulfilled by using TLD and MOSFET. The other side of breast dose was the lowest in the open beam, on the other hand, is highest in the Dose fluence plan. In the different kinds of treatment, the dose deviation of inner and outer was the highest, and so this was the same with the TLD and MOSFET measurement case. The outer deviation was highest in the TLD, and the Inner' was highest in the MOSFET. Skin dose in relation to the treatment plan was the highest in the planing using the fluence technique in general and it was supposed that the high dose had been caused by the movement of the MLC. There's some differences among the all the treatment planning, but the sites such as IM node occurring the lack of dose, scar, drain site are needed pay

  17. The study on clinical conditions and skin dose of upper-gastrointestinal x-ray fluoroscopy

    International Nuclear Information System (INIS)

    Kim, Sung Chul; Ahn, Sung Min; Jang, Sang Sup

    2007-01-01

    This study examined present conditions of upper-gastrointestinal X-ray fluoroscopy and patient skin dose. The authors elected 21 equipment to check the X-ray equipment and exposure factor of fluoroscopy and spot exposure in university hospitals, hospitals, and clinics where perform upper-gastrointestinal X-ray fluoroscopy more than five times every day in Incheon areas. The amount of patient's skin dose during upper-gastrointestinal X-ray fluoroscopy was measured by ionization chamber

  18. Ingestion of Nevada Test Site Fallout: Internal dose estimates

    International Nuclear Information System (INIS)

    Whicker, F.W.; Kirchner, T.B.; Anspaugh, L.R.

    1996-01-01

    This paper summarizes individual and collective dose estimates for the internal organs of hypothetical yet representative residents of selected communities that received measurable fallout from nuclear detonations at the Nevada Test Site. The doses, which resulted from ingestion of local and regional food products contaminated with over 20 radionuclides, were estimated with use of the PATHWAY food-chain-transport model to provide estimates of central tendency and uncertainty. The thyroid gland received much higher doses than other internal organs and tissues. In a avery few cases, infants might have received thyroid doses in excess of 1 Gy, depending on location, diet, and timing of fallout. 131 I was the primary thyroid dose contributor, and fresh milk was the main exposure pathway. With the exception of the thyroid, organ doses from the ingestion pathway were much smaller (<3%) than those from external gamma exposure to deposited fallout. Doses to residents living closest to the Nevada Test Site were contributed mainly by a few fallout events; doses to more distantly located people were generally smaller, but a greater number of events provided measurable contributions. The effectiveness of different fallout events in producing internal organ doses through ingestion varied dramatically with seasonal timing of the test, with maximum dose per unit fallout occurring for early summer depositions when milk cows were on pasture and fresh, local vegetables were used. Within specific communities, internal doses differed by age, sex, and lifestyle. Collective internal dose estimates for specific geographic areas are provided

  19. Validation of radiosterilization dose of human skin dressings for burnt treatment: preliminary study

    International Nuclear Information System (INIS)

    Castro, E.

    2008-01-01

    Full text: Due to the need for better materials to treat burnt patients, the Peruvian Institute of Nuclear Energy (IPEN) and the Rosa Guerzoni Chambergo Tissue Bank are collaborating for developing human skin dressings. Skin was procured from living donors, who surgically were performed a dermolipectomy. Exclusion criteria, stated by the Peruvian Organization for Transplant and Donation were observed. Glycerolized human skin dressings were processed at the tissue bank and sent to IPEN, where the gamma irradiation sterilizing dose was determined. The purpose of this work is to validate the radiation sterilization dose delivered to human skin dressings using the IAEA Code of Practice for the Radiation Sterilization of Tissue Allografts: Requirements for Validation and Routine Control. A batch of human skin dressings was tested. Average values of bioburden present in ten samples was 30 UFC/item, obtaining a sub-sterilization dose of 4 kGy. Irradiations were performed in the GammacellExcel 220. Sterility tests performed fulfilled the requirements established by the Code, achieving a validated dose value of 19.7 kGy. This preliminary study, that should be repeated in two other batches of processed human skin, allows to diminish 25 kGy the sterilizing dose to the stated above dose value, in a frame of a quality assurance system that also comprises the processes held at tissue banks previous irradiation. It also permit the availability of these materials in Peruvian hospitals. (Author)

  20. Natural radiation dose estimates from soils

    International Nuclear Information System (INIS)

    Silveira, M.A.G.R.; Moreira, H.; Medina, N.H.

    2009-01-01

    In this work the natural radiation from soils of southeastern Brazil has been studied. Soil samples from Interlagos, Sao Paulo; parks and Billings dam, in Sao Bernardo do Campo city; Santos, Sao Vicente and Sao Sebastiao beaches, Sao Paulo and sands from Ilha Grande beaches, Rio de Janeiro, were analyzed. The results show that the main contribution to the effective dose is due to elements of the 232 Th decay chain, with a smaller contribution from the radionuclide 40 K and the elements of the series of 238 U. The obtained values found in the studied regions, are around the average international dose due to external exposure to gamma rays (0.48 mSv/yr), except in Praia Preta, Ilha Grande, where the effective dose exceeds the average value. (author)

  1. Multicenter study on evaluation of the entrance skin dose by a direct measurement method in cardiac interventional procedures

    International Nuclear Information System (INIS)

    Kato, Mamoru; Chida, Koichi; Moritake, Takashi

    2016-01-01

    Deterministic effects have been reported in cardiac interventional procedures. To prevent radiation skin injuries in percutaneous coronary intervention (PCI), it is necessary to measure accurate patient entrance skin dose (ESD) and maximum skin absorbed dose (MSD). We measured the MSD on 62 patients in four facilities by using the Chest-RADIREC system. The correlation between MSD and fluoroscopic time, dose area product (DAP), and cumulative air kerma (AK) showed good results, with the correlation between MSD and AK being the strongest. The regression lines using MSD as an outcome value (y) and AK as predictor variables (x) was y=1.18x (R 2 =0.787). From the linear regression equation, MSD is estimated to be about 1.18 times that of AK in real time. The Japan diagnostic reference levels (DRLs) 2015 for IVR was established by the use of dose rates using acrylic plates (20 cm thick) at the interventional reference point. Preliminary reference levels proposed by International Atomic Energy Agency (IAEA) were provided using DAP. In this study, AK showed good correlation most of all. Hence we think that Japanese DRLs for IVR should reconsider by clinical patients' exposure dose such as AK. (author)

  2. Occupational dose estimates for a monitored retrievable storage facility

    International Nuclear Information System (INIS)

    Harty, R.; Stoetzel, G.A.

    1986-06-01

    Occupational doses were estimated for radiation workers at the monitored retrievable storage (MRS) facility. This study provides an estimate of the occupational dose based on the current MRS facility design, examines the extent that various design parameters and assumptions affect the dose estimates, and identifies the areas and activities where exposures can be reduced most effectively. Occupational doses were estimated for both the primary storage concept and the alternate storage concept. The dose estimates indicate the annual dose to all radiation workers will be below the 5 rem/yr federal dose equivalent limit. However, the estimated dose to most of the receiving and storage crew (the workers responsible for the receipt, storage, and surveillance of the spent fuel and its subsequent retrieval), to the crane maintenance technicians, and to the cold and remote maintenance technicians is above the design objective of 1 rem/yr. The highest annual dose is received by the riggers (4.7 rem) in the receiving and storage crew. An indication of the extent to which various design parameters and assumptions affect the dose estimates was obtained by changing various design-based assumptions such as work procedures, background dose rates in radiation zones, and the amount of fuel received and stored annually. The study indicated that a combination of remote operations, increased shielding, and additional personnel (for specific jobs) or changes in operating procedures will be necessary to reduce worker doses below 1.0 rem/yr. Operations that could be made at least partially remote include the removal and replacement of the tiedowns, impact limiters, and personnel barriers from the shipping casks and the removal or installation of the inner closure bolts. Reductions of the background dose rates in the receiving/shipping and the transfer/discharge areas may be accomplished with additional shielding

  3. Dosimetry studies with 32P source and correlation of skin and eye lens doses

    International Nuclear Information System (INIS)

    Kumar, Munish; Gaonkar, U.P.; Koul, D.K.; Datta, D.; Saxena, S.K.; Kumar, Yogendra; Dash, A.

    2018-01-01

    Beta particles are one of the major contributors toward skin and eye lens doses at facilities handling beta sources. These sources find applications in industry, pharmaceuticals as well as in brachytherapy applications. The beta particles having maximum (E max ) energy > 0.07 MeV are capable of delivering skin dose whereas beta particles having maximum (E max ) energy > 0.7 MeV may also contribute towards dose to eye lens. Studies are performed using 32 P beta source as its maximum beta energy (E max ) is such that for sources having (E max ) of 1.71 MeV or beyond, there can be substantial contribution towards dose to eye lens even the dose limit recommended for skin is followed

  4. Dose uniformity estimations in the blood irradiator

    International Nuclear Information System (INIS)

    George, J.R.

    2002-01-01

    Use of irradiated blood in transfusions is recognized as the most effective way of preventing Graft Versus Host Disease (GVHD). This paper shows the study carried out in the dose rate variation for various source arrangements for optimising the source-sample chamber geometry, during the development of the Blood Irradiator, Bl-2000

  5. Radiofrequency catheter ablation: Relationship between fluoroscopic time and skin doses according to diagnoses. Basis to establish a quality assurance programme

    International Nuclear Information System (INIS)

    Cotelo, E.; Pouso, J.; Reyes, W.

    2001-01-01

    Radiofrequency Cardiac Catheter Ablation is an Interventional Radiology procedure of great complexity because the cardiologist needs a simultaneous evaluation of fluoroscopic images and electrophysiologic information. Therefore, the procedure typically involves extended fluoroscopic time that may cause radiation-skin injures to patients. Skin doses depend on many factors: equipment design features and its proper use, cardiologist practice, fluoroscopic time, irradiated areas, application of radiation protection recommendations, etc. We evaluate fluoroscopic time in relation to pathology and we estimate skin doses on 233 procedures at the Electrophysiology Laboratory in Casa de Galicia, Montevideo, Uruguay. Significant differences among the medians of fluoroscopic time were found in those procedures depending on diagnoses and results. Higher fluoroscopic time was found in flutter and auricular tachycardia (median was 83 minutes, p=0.0001). In successful procedures (almost 90%), median skin doses was 2.0 Grays (p=0.0001). On the basis of records information, the standard operating procedure and the clinical protocol, expanding close cooperation between the cardiologists and the experts in Radiation Protection will secure the establishment of an Assurance Quality Program. (author)

  6. Clinical application of a OneDose(TM) MOSFET for skin dose measurements during internal mammary chain irradiation with high dose rate brachytherapy in carcinoma of the breast

    International Nuclear Information System (INIS)

    Kinhikar, Rajesh A; Sharma, Pramod K; Tambe, Chandrashekhar M; Mahantshetty, Umesh M; Sarin, Rajiv; Deshpande, Deepak D; Shrivastava, Shyam K

    2006-01-01

    In our earlier study, we experimentally evaluated the characteristics of a newly designed metal oxide semiconductor field effect transistor (MOSFET) OneDose(TM) in-vivo dosimetry system for Ir-192 (380 keV) energy and the results were compared with thermoluminescent dosimeters (TLDs). We have now extended the same study to the clinical application of this MOSFET as an in-vivo dosimetry system. The MOSFET was used during high dose rate brachytherapy (HDRBT) of internal mammary chain (IMC) irradiation for a carcinoma of the breast. The aim of this study was to measure the skin dose during IMC irradiation with a MOSFET and a TLD and compare it with the calculated dose with a treatment planning system (TPS). The skin dose was measured for ten patients. All the patients' treatment was planned on a PLATO treatment planning system. TLD measurements were performed to compare the accuracy of the measured results from the MOSFET. The mean doses measured with the MOSFET and the TLD were identical (0.5392 Gy, 15.85% of the prescribed dose). The mean dose was overestimated by the TPS and was 0.5923 Gy (17.42% of the prescribed dose). The TPS overestimated the skin dose by 9% as verified by the MOSFET and TLD. The MOSFET provides adequate in-vivo dosimetry for HDRBT. Immediate readout after irradiation, small size, permanent storage of dose and ease of use make the MOSFET a viable alternative for TLDs. (note)

  7. Clinical application of a OneDose MOSFET for skin dose measurements during internal mammary chain irradiation with high dose rate brachytherapy in carcinoma of the breast.

    Science.gov (United States)

    Kinhikar, Rajesh A; Sharma, Pramod K; Tambe, Chandrashekhar M; Mahantshetty, Umesh M; Sarin, Rajiv; Deshpande, Deepak D; Shrivastava, Shyam K

    2006-07-21

    In our earlier study, we experimentally evaluated the characteristics of a newly designed metal oxide semiconductor field effect transistor (MOSFET) OneDose in-vivo dosimetry system for Ir-192 (380 keV) energy and the results were compared with thermoluminescent dosimeters (TLDs). We have now extended the same study to the clinical application of this MOSFET as an in-vivo dosimetry system. The MOSFET was used during high dose rate brachytherapy (HDRBT) of internal mammary chain (IMC) irradiation for a carcinoma of the breast. The aim of this study was to measure the skin dose during IMC irradiation with a MOSFET and a TLD and compare it with the calculated dose with a treatment planning system (TPS). The skin dose was measured for ten patients. All the patients' treatment was planned on a PLATO treatment planning system. TLD measurements were performed to compare the accuracy of the measured results from the MOSFET. The mean doses measured with the MOSFET and the TLD were identical (0.5392 Gy, 15.85% of the prescribed dose). The mean dose was overestimated by the TPS and was 0.5923 Gy (17.42% of the prescribed dose). The TPS overestimated the skin dose by 9% as verified by the MOSFET and TLD. The MOSFET provides adequate in-vivo dosimetry for HDRBT. Immediate readout after irradiation, small size, permanent storage of dose and ease of use make the MOSFET a viable alternative for TLDs.

  8. Evaluating the consistency of location of the most severe acute skin reaction and highest skin dose measured by thermoluminescent dosimeter during radiotherapy for breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Li-Min, E-mail: limin.sun@yahoo.com [Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China); Huang, Chih-Jen [Department of Radiation Oncology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Faculty of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of College of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Chen, Hsiao-Yun [Department of Radiation Oncology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Chang, Gia-Hsin [Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China); Tsao, Min-Jen [Department of General Surgery, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung City, Taiwan (China)

    2016-10-01

    We conducted this prospective study to evaluate whether the location of the most severe acute skin reaction matches the highest skin dose measured by thermoluminescent dosimeter (TLD) during adjuvant radiotherapy (RT) for patients with breast cancer after breast conservative surgery. To determine whether TLD measurement can reflect the location of the most severe acute skin reaction, 80 consecutive patients were enrolled in this prospective study. We divided the irradiated field into breast, axillary, inframammary fold, and areola/nipple areas. In 1 treatment session when obvious skin reaction occurred, we placed the TLD chips onto the 4 areas and measured the skin dose. We determined whether the highest measured skin dose area is consistent with the location of the most severe skin reaction. The McNemar test revealed that the clinical skin reaction and TLD measurement are more consistent when the most severe skin reaction occurred at the axillary area, and the p = 0.0108. On the contrary, TLD measurement of skin dose is less likely consistent with clinical observation when the most severe skin reaction occurred at the inframammary fold, breast, and areola/nipple areas (all the p > 0.05). Considering the common site of severe skin reaction over the axillary area, TLD measurement may be an appropriate way to predict skin reaction during RT.

  9. Assessment of skin dose modification caused by application of immobilizing cast in head and neck radiotherapy

    International Nuclear Information System (INIS)

    Soleymanifard, Shokouhozaman; Toossi, Mohammad T.B.; Khosroabadi, Mohsen; Noghreiyan, Atefeh Vejdani; Shahidsales, Soodabeh; Tabrizi, Fatemeh Varshoee

    2014-01-01

    Skin dose assessment for radiotherapy patients is important to ensure that the dose received by skin is not excessive and does not cause skin reactions. Immobilizing casts may have a buildup effect, and can enhance the skin dose. This study has quantified changes to the surface dose as a result of head and neck immobilizing casts. Medtech and Renfu casts were stretched on the head of an Alderson Rando-Phantom. Irradiation was performed using 6 and 15 MV X-rays, and surface dose was measured by thermoluminescence dosimeters. In the case of 15MV photons, immobilizing casts had no effect on the surface dose. However, the mean surface dose increase reached up to 20 % when 6MV X-rays were applied. Radiation incidence angle, thickness, and meshed pattern of the casts affected the quantity of dose enhancement. For vertical beams, the surface dose increase was more than tangential beams, and when doses of the points under different areas of the casts were analysed separately, results showed that only doses of the points under the thick area had been changed. Doses of the points under the thin area and those within the holes were identical to the same points without immobilizing casts. Higher dose which was incurred due to application of immobilizing casts (20 %) would not affect the quality of life and treatment of patients whose head and neck are treated. Therefore, the benefits of head and neck thermoplastic casts are more than their detriments. However, producing thinner casts with larger holes may reduce the dose enhancement effect.

  10. Cellular vs. organ approaches to dose estimates

    International Nuclear Information System (INIS)

    Adelstein, S.J.; Kassis, A.I.; Sastry, K.S.R.

    1986-01-01

    The cellular distribution of tissue-incorporated radionuclides has generally been neglected in the dosimetry of internal emitters. Traditional dosimetry assumes homogeneous distribution of radionuclides in organs of interest, while presuming that the ranges of particulate radiations are large relative to typical cell diameters. The macroscopic distribution of dose thus calculated has generally served as a sufficient approximation for the energy deposited within radiosensitive sites. However, with the increasing utilization of intracellular agents, such as thallium-201, it has become necessary to examine the microscopic distribution of energy at the cellular level. This is particularly important in the instance of radionuclides that decay by electron capture or by internal conversion with the release of Auger and Coster-Kronig electrons. In many instances, these electrons are released as a dense shower of low-energy particles with ranges of subcellular dimensions. The high electron density in the immediate vicinity of the decaying atom produces a focal deposition of energy that far exceeds the average dose taken over several cell diameters. These studies point out the increasing need to take into account the microscopic distribution of dose on the cellular level as radionuclides distributed in cells become more commonplace, especially if the decay involves electron capture or internal conversion. As radiotracers are developed for the measurement of intracellular functions these factors should be given greater consideration. 16 references, 5 figures, 5 tables

  11. Nonparametric estimation of benchmark doses in environmental risk assessment

    Science.gov (United States)

    Piegorsch, Walter W.; Xiong, Hui; Bhattacharya, Rabi N.; Lin, Lizhen

    2013-01-01

    Summary An important statistical objective in environmental risk analysis is estimation of minimum exposure levels, called benchmark doses (BMDs), that induce a pre-specified benchmark response in a dose-response experiment. In such settings, representations of the risk are traditionally based on a parametric dose-response model. It is a well-known concern, however, that if the chosen parametric form is misspecified, inaccurate and possibly unsafe low-dose inferences can result. We apply a nonparametric approach for calculating benchmark doses, based on an isotonic regression method for dose-response estimation with quantal-response data (Bhattacharya and Kong, 2007). We determine the large-sample properties of the estimator, develop bootstrap-based confidence limits on the BMDs, and explore the confidence limits’ small-sample properties via a short simulation study. An example from cancer risk assessment illustrates the calculations. PMID:23914133

  12. TH-AB-207A-03: Skin Dose to Patients Receiving Multiple CTA and CT Exams of the Head

    International Nuclear Information System (INIS)

    Nawfel, RD; Young, G

    2016-01-01

    Purpose: To measure patient skin dose from CT angiography (CTA) and CT exams of the head, and determine if patients having multiple exams could receive cumulative doses that approach or exceed deterministic thresholds. Methods: This study was HIPAA compliant and conducted with IRB approval. Patient skin doses were measured over a 4 month period using nanoDot OSL dosimeters placed on the head of 52 patients for two CT scanners. On each scanner, 26 patients received CT exams (scanner 1: 10 females, 16 males, mean age 64.2 years; scanner 2: 18 females, 8 males, mean age 61.2 years). CT exam dose metrics, CTDIvol and dose-length product (DLP) were recorded for each exam. Additionally, skin dose was measured on an acrylic skull phantom in each scanner and on a neuro-interventional imaging system using clinical protocols. Measured dose data was used to estimate peak skin dose (PSD) for 4 patients receiving multiple exams including CTA, head CT, and cerebral angiography. Results: For scanner 1, the mean PSD for CTA exams (98.9 ± 5.3 mGy) and for routine head CT exams (39.2 ± 3.7 mGy) agreed reasonably well with the PSD measured on the phantom, 105.4 mGy and 40.0 mGy, respectively. Similarly for scanner 2, the mean PSD for CTA exams (98.8 ± 7.4 mGy) and for routine head CT exams (42.9 ± 9.4 mGy) compared well with phantom measurements, 95.2 mGy and 37.6 mGy, respectively. In addition, the mean PSD was comparable between scanners for corresponding patient exams, CTA and routine head CT respectively. PSD estimates ranged from 1.9 – 4.5 Gy among 4 patients receiving multiple exams. Conclusion: Patients having several exams including both CTA and routine head CT may receive cumulative doses approaching or exceeding the threshold for single dose deterministic effects.

  13. TH-AB-207A-03: Skin Dose to Patients Receiving Multiple CTA and CT Exams of the Head

    Energy Technology Data Exchange (ETDEWEB)

    Nawfel, RD; Young, G [Brigham & Women’s Hospital, Boston, MA (United States)

    2016-06-15

    Purpose: To measure patient skin dose from CT angiography (CTA) and CT exams of the head, and determine if patients having multiple exams could receive cumulative doses that approach or exceed deterministic thresholds. Methods: This study was HIPAA compliant and conducted with IRB approval. Patient skin doses were measured over a 4 month period using nanoDot OSL dosimeters placed on the head of 52 patients for two CT scanners. On each scanner, 26 patients received CT exams (scanner 1: 10 females, 16 males, mean age 64.2 years; scanner 2: 18 females, 8 males, mean age 61.2 years). CT exam dose metrics, CTDIvol and dose-length product (DLP) were recorded for each exam. Additionally, skin dose was measured on an acrylic skull phantom in each scanner and on a neuro-interventional imaging system using clinical protocols. Measured dose data was used to estimate peak skin dose (PSD) for 4 patients receiving multiple exams including CTA, head CT, and cerebral angiography. Results: For scanner 1, the mean PSD for CTA exams (98.9 ± 5.3 mGy) and for routine head CT exams (39.2 ± 3.7 mGy) agreed reasonably well with the PSD measured on the phantom, 105.4 mGy and 40.0 mGy, respectively. Similarly for scanner 2, the mean PSD for CTA exams (98.8 ± 7.4 mGy) and for routine head CT exams (42.9 ± 9.4 mGy) compared well with phantom measurements, 95.2 mGy and 37.6 mGy, respectively. In addition, the mean PSD was comparable between scanners for corresponding patient exams, CTA and routine head CT respectively. PSD estimates ranged from 1.9 – 4.5 Gy among 4 patients receiving multiple exams. Conclusion: Patients having several exams including both CTA and routine head CT may receive cumulative doses approaching or exceeding the threshold for single dose deterministic effects.

  14. Monte Carlo estimation of the absorbed dose in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Woo; Youn, Han Bean; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of)

    2016-05-15

    The purpose of this study is to devise an algorithm calculating absorbed dose distributions of patients based on Monte Carlo (MC) methods, and which includes the dose estimations due to primary and secondary (scattered) x-ray photons. Assessment of patient dose in computed tomography (CT) at the population level has become a subject of public attention and concern, and ultimate CT quality assurance and dose optimization have the goal of reducing radiation-induced cancer risks in the examined population. However, the conventional CT dose index (CTDI) concept is not a surrogate of risk but it has rather been designed to measure an average central dose. In addition, the CTDI or the dose-length product has showed troubles for helical CT with a wider beam collimation. Simple algorithms to estimate a patient specific CT dose based on the MCNP output data have been introduced. For numerical chest and head phantoms, the spatial dose distributions were calculated. The results were reasonable. The estimated dose distribution map can be readily converted into the effective dose. The important list for further studies includes the validation of the models with the experimental measurements and the acceleration of algorithms.

  15. A beta skin dose monitor using an Eberline RO-2 ion chamber

    International Nuclear Information System (INIS)

    Jester, W.A.; Levine, S.H.; Lin, T.J.; Hock, R.

    1994-01-01

    The authors have developed a portable beta skin dose monitor that uses an Eberline RO-2trademark ion chamber. The development was based, in part, upon the previous development of a beta skin dose monitor employing silicon detectors. In this current work, the two entrance windows of the RO-2 were replaced by windows having a total mass thickness of 1.74 mg/cm 2 . A two section source-detector holder was constructed. One section fastens to the RO-2 and holds the detector at the right position to determine the contact skin dose from beta emitters located on surfaces. A second section attaches to the first, and provides fixed counting geometry for radioactive samples such as hot particles. The first section also contains a slide mechanism that allows the placement of absorbers of zero (0), 8.38, and 1000 mg/cm 2 between the detector window and the beta source. The detector response to these absorbers allows for the determination of beta skin dose. The system was modeled using a Monte Carlo beta attenuation code computing the beta skin dose to RO-2 detector response as a function of absorber thickness, average beta energy, source diameter and source position. Using the RO-2 reading from each of the three absorber configurations allows the calculation of beta skin dose and the average beta energy. The results of these calculations were confirmed through the use of three massless radioactive beta sources, traceable to the National Institute of Standards and Technology, and several utility-supplied hot particles having well-established contact skin doses. An extrapolation chamber was also used to confirm the results obtained from this monitor. This system is now use at the Pennsylvania Power and Light (PP and L) Company, the project sponsor. ((orig.))

  16. Dose estimation in embryo or fetus in external fields

    International Nuclear Information System (INIS)

    Gregori, Beatriz N.

    2001-01-01

    The embryo or the fetus can be irradiated as result of radiological procedures of diagnosis of therapy in where the beam effects directly on the same one or in tissues or peripherical organs. Some authors have suggested that in the first stages of the pregnancy the dose in ovaries can be the good estimated of the dose in embryo or fetus. In advanced conditions of the development, probably also in the early stage, is more appropriated to specify the dose in the embryo or fetus equal of the uterus. The dose in the uterus is a good estimated so much for external irradiation as for radionuclides incorporation

  17. Adult head CT scans: the uncertainties of effective dose estimates

    International Nuclear Information System (INIS)

    Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E.

    2008-01-01

    Full Text: CT scanning is a high dose imaging modality. Effective dose estimates from CT scans can provide important information to patients and medical professionals. For example, medical practitioners can use the dose to estimate the risk to the patient, and judge whether this risk is outweighed by the benefits of the CT examination, while radiographers can gauge the effect of different scanning protocols on the patient effective dose, and take this into consideration when establishing routine scan settings. Dose estimates also form an important part of epidemiological studies examining the health effects of medical radiation exposures on the wider population. Medical physicists have been devoting significant effort towards estimating patient radiation doses from diagnostic CT scans for some years. The question arises: How accurate are these effective dose estimates? The need for a greater understanding and improvement of the uncertainties in CT dose estimates is now gaining recognition as an important issue (BEIR VII 2006). This study is an attempt to analyse and quantify the uncertainty components relating to effective dose estimates from adult head CT examinations that are calculated with four commonly used methods. The dose estimation methods analysed are the Nagel method, the ImpaCT method, the Wellhoefer method and the Dose-Length Product (DLP) method. The analysis of the uncertainties was performed in accordance with the International Standards Organisation's Guide to the Expression of Uncertainty in Measurement as discussed in Gregory et al (Australas. Phys. Eng. Sci. Med., 28: 131-139, 2005). The uncertainty components vary, depending on the method used to derive the effective dose estimate. Uncertainty components in this study include the statistical and other errors from Monte Carlo simulations, uncertainties in the CT settings and positions of patients in the CT gantry, calibration errors from pencil ionization chambers, the variations in the organ

  18. patient entrance skin doses at minna and ibadan for common

    African Journals Online (AJOL)

    DR. AMINU

    Entrance surface dose from two diagnostic x-ray centers in Nigeria for three common radiological examinations is .... typical ESD values for adult patients for three different ... TTX located in the region of Nigeria where regulatory activities have ...

  19. Generalized concept for the estimation of body dose for radiation workers exposed to external #betta#-rays

    International Nuclear Information System (INIS)

    Piesch, E.; Boehm, J.; Heinzelmann, M.

    1983-01-01

    In radiation protection monitoring the need exists for an estimation of body dose due to external #betta#-rays, for instance if the #betta#-dose rate at the working area is expected to be high according to the data of source activity or room contamination, the indicated dose values of a personal dosemeter exceed the operational limit for the organ or tissue depth of interest, or a person was exposed to a significant dose. On behalf of the Federal Ministry of the Interior, Federal Republic of Germany, a guideline is now under preparation which offers a standardized concept of the estimation of #betta#-doses in personnel monitoring. The calculation models discussed here will be used as a basis for any case of external #betta#-irradiation where, in connection with the German Radiation Protection Ordinance, the ICRP dose equivalent limits are reached or the dosemeter readings are not representative for an individual exposure. The generalized concept discussed in the paper relates to: the calculation of #betta#-dose on the basis of source activity or spectral particle fluence and takes into account the special cases of point sources, area sources and volume sources; the estimation of body dose on the basis of calculated data or measured results from area or personnel monitoring, taking into account the dose equivalent in different depths of tissue, in particular the dose equivalent to the skin, the lens of the eye and other organs; and finally the estimation of skin dose due to the contamination of the skin surface. Basic reference data are presented in order to estimate the dose equivalent of interest which varies significantly in the #betta#-radiation field as a function of the maximum #betta#-energy, distance to the source, size of the source, activity per area for surface contamination and activity per volume for air contamination

  20. Estimation of organ doses of patient undergoing hepatic chemoembolization procedures

    International Nuclear Information System (INIS)

    Jaramillo, G.W.; Kramer, R.; Khoury, H.J.; Barros, V.S.M.; Andrade, G.

    2015-01-01

    The aim of this study is to evaluate the organ doses of patients undergoing hepatic chemoembolization procedures performed in two hospitals in the city of Recife-Brazil. Forty eight patients undergoing fifty hepatic chemoembolization procedures were investigated. For the 20 cases with PA projection only, organ and tissue absorbed doses as well as radiation risks were calculated. For this purpose organs and tissues dose to KAP conversion coefficients were calculated using the mesh-based phantom series FASH and MASH coupled to the EGSnrc Monte Carlo code. Clinical, dosimetric and irradiations parameters were registered for all patients. The maximum organ doses found were 1.72 Gy, 0.65Gy, 0.56 Gy and 0.33 Gy for skin, kidneys, adrenals and liver, respectively. (authors)

  1. Dose estimates in Japan following the Chernobyl reactor accident

    International Nuclear Information System (INIS)

    Togawa, Orihiko; Homma, Toshimitsu; Iijima, Toshinori; Midorikawa, Yuji.

    1988-02-01

    Estimates have been made of the maximum individual doses and the collective doses in Japan following the Chernobyl reactor accident. Based on the measured data of ground deposition and radionuclide concentrations in air, raw milk, milk on sale and leafy vegetables, the doses from some significant radionuclides were calculated for 5 typical exposure pathways; cloudshine, groundshine, inhalation, ingestion of milk and leafy vegetables. The maximum effective dose equivalents for hypothetical individuals were calculated to be 1.8 mrem for adults, 3.7 mrem for children and 6.0 mrem for infants. The collective effective dose equivalent in Japan was estimated to be 5.8 x 10 4 man · rem; 0.50 mrem of the average dose per capita. (author)

  2. Dose estimation from residual and fallout radioactivity, 1

    International Nuclear Information System (INIS)

    Takeshita, Kenji

    1975-01-01

    External dose rates and cumulative doses for early entrants from areal surveys and simulated experiments are reviewed. The average cumulative doses to infinity at the hypocenters were 101 rad in Hiroshima and 32 rad in Nagasaki, with a variation of about 60 percent. Radioactive fallout areas nearly matched the ''black rain'' areas in Nagasaki and in Hiroshima. Radioactivity in the fallout areas was affected by radioactive decay and by the leaching and dissipation by rains. Considering these factors, the cumulative dose to infinity in the fallout area of Hiroshima was estimated to be 13 rad, excluding internal radiation doses from inhaled and ingested radionuclides. Attempts to estimate radiation dose from internally deposited radionuclides are also described. (auth.)

  3. Size-specific dose estimate (SSDE) provides a simple method to calculate organ dose for pediatric CT examinations

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Bria M.; Brady, Samuel L., E-mail: samuel.brady@stjude.org; Kaufman, Robert A. [Department of Radiological Sciences, St Jude Children' s Research Hospital, Memphis, Tennessee 38105 (United States); Mirro, Amy E. [Department of Biomedical Engineering, Washington University, St Louis, Missouri 63130 (United States)

    2014-07-15

    Purpose: To investigate the correlation of size-specific dose estimate (SSDE) with absorbed organ dose, and to develop a simple methodology for estimating patient organ dose in a pediatric population (5–55 kg). Methods: Four physical anthropomorphic phantoms representing a range of pediatric body habitus were scanned with metal oxide semiconductor field effect transistor (MOSFET) dosimeters placed at 23 organ locations to determine absolute organ dose. Phantom absolute organ dose was divided by phantom SSDE to determine correlation between organ dose and SSDE. Organ dose correlation factors (CF{sub SSDE}{sup organ}) were then multiplied by patient-specific SSDE to estimate patient organ dose. The CF{sub SSDE}{sup organ} were used to retrospectively estimate individual organ doses from 352 chest and 241 abdominopelvic pediatric CT examinations, where mean patient weight was 22 kg ± 15 (range 5–55 kg), and mean patient age was 6 yrs ± 5 (range 4 months to 23 yrs). Patient organ dose estimates were compared to published pediatric Monte Carlo study results. Results: Phantom effective diameters were matched with patient population effective diameters to within 4 cm; thus, showing appropriate scalability of the phantoms across the entire pediatric population in this study. IndividualCF{sub SSDE}{sup organ} were determined for a total of 23 organs in the chest and abdominopelvic region across nine weight subcategories. For organs fully covered by the scan volume, correlation in the chest (average 1.1; range 0.7–1.4) and abdominopelvic region (average 0.9; range 0.7–1.3) was near unity. For organ/tissue that extended beyond the scan volume (i.e., skin, bone marrow, and bone surface), correlation was determined to be poor (average 0.3; range: 0.1–0.4) for both the chest and abdominopelvic regions, respectively. A means to estimate patient organ dose was demonstrated. Calculated patient organ dose, using patient SSDE and CF{sub SSDE}{sup organ}, was compared to

  4. Accelerated partial-breast irradiation with interstitial implants. The clinical relevance of the calculation of skin doses

    International Nuclear Information System (INIS)

    Ott, O.J.; Lotter, M.; Sauer, R.; Strnad, V.

    2007-01-01

    Purpose: To describe relative skin dose estimations and their impact on cosmetic outcome in interstitial multicatheter accelerated partial-breast irradiation (APBI). Patients and Methods: Between April 2001 and January 2005, 105 consecutive patients with early breast cancer were recruited in Erlangen, Germany, for this substudy of the German-Austrian APBI phase II trial. 51% (54/105) received pulsed-dose-rate (PDR), and 49% (51/105) high-dose-rate (HDR) brachytherapy. Prescribed reference dose for HDR brachytherapy was 32 Gy in eight fractions of 4 Gy, twice daily. Prescribed reference dose in PDR brachytherapy was 49.8 Gy in 83 consecutive fractions of 0.6 Gy every hour. Total treatment time was 3-4 days. With a wire cross on the skin surface during the brachytherapy-planning procedure the minimal, mean and maximal relative skin doses (SD min% , SD max% , SD mean% ) were recorded. Endpoint of this evaluation was the cosmetic outcome in relation to the relative skin doses. Results: Median follow-up time was 38 months (range, 19-65 months). Cosmetic results for all patients were excellent in 57% (60/105), good in 36% (38/105), and fair in 7% (7/105). The SD min% (27.0% vs. 31.7%; p = 0.032), SD mean% (34.2% vs. 38.1%; p 0.008), and SD max% (38.2% vs. 46.4%; p 0.003) were significantly lower for patients with excellent cosmetic outcome compared to patients with a suboptimal outcome. SD mean% (37.6% vs. 34.2%; p = 0.026) and SD max% (45.4% vs. 38.2%; p = 0.008) were significantly higher for patients with good cosmetic outcome compared with the patients with excellent results. Conclusion: The appraisal of skin doses has been shown to be relevant to the achievement of excellent cosmetic outcome. Further investigations are necessary, especially on the basis of CT-based brachytherapy planning, to further improve the treatment results of multicatheter APBI. (orig.)

  5. Cytogenetic biological dosimetry. Dose estimative in accidental exposure

    International Nuclear Information System (INIS)

    Santos, O.R. dos; Campos, I.M.A. de.

    1988-01-01

    The methodology of cytogenetic biological dosimetry is studied. The application in estimation of dose in five cases of accidental exposure is reported. An hematological study and culture of lymphocytes is presented. (M.A.C.) [pt

  6. Evaluation of the entrance skin dose due to paediatric chest X-rays examinations carried out at a great hospital in Rio de Janeiro city

    International Nuclear Information System (INIS)

    Mohamadain, K.E.M.; Azevedo, A.C.P.; Rosa, L.A.R. da; Mota, H.C.; Goncalves, O.D.; Guebel, M.R.N.

    2001-01-01

    A dosimetric survey in paediatric radiology is currently being carried out at the paediatric unit of a great hospital in Rio de Janeiro city, aiming the assessment of patient doses and image quality. The aim of this work was to estimate the entrance skin dose for frontal and lateral chest X-rays exposure to paediatric patients. Three examination techniques were investigated, namely PA, AP and lateral positions. For entrance skin dose evaluation, two different TL dosimeters were used, namely LiF:Mg,Ti and CaSO4:Dy. The age intervals considered were 0-1 year, 1-5 years, 5-10 years and 10-15 years. The results obtained with both dosimeters are similar and the entrance skin dose values evaluated for the different age intervals considered are compared with previous values found in Brazil and also in Europe. (author)

  7. Sample Based Unit Liter Dose Estimates

    International Nuclear Information System (INIS)

    JENSEN, L.

    2000-01-01

    The Tank Waste Characterization Program has taken many core samples, grab samples, and auger samples from the single-shell and double-shell tanks during the past 10 years. Consequently, the amount of sample data available has increased, both in terms of quantity of sample results and the number of tanks characterized. More and better data is available than when the current radiological and toxicological source terms used in the Basis for Interim Operation (BIO) (FDH 1999a) and the Final Safety Analysis Report (FSAR) (FDH 1999b) were developed. The Nuclear Safety and Licensing (NS and L) organization wants to use the new data to upgrade the radiological and toxicological source terms used in the BIO and FSAR. The NS and L organization requested assistance in producing a statistically based process for developing the source terms. This report describes the statistical techniques used and the assumptions made to support the development of a new radiological source term for liquid and solid wastes stored in single-shell and double-shell tanks. The results given in this report are a revision to similar results given in an earlier version of the document (Jensen and Wilmarth 1999). The main difference between the results in this document and the earlier version is that the dose conversion factors (DCF) for converting μCi/g or μCi/L to Sv/L (sieverts per liter) have changed. There are now two DCFs, one based on ICRP-68 and one based on ICW-71 (Brevick 2000)

  8. beta. and. gamma. -comparative dose estimates on Enewetak Atoll

    Energy Technology Data Exchange (ETDEWEB)

    Crase, K.W.; Gudiksen, P.H.; Robison, W.L. (California Univ., Livermore (USA). Lawrence Livermore National Lab.)

    1982-05-01

    Enewetak Atoll in the Pacific is used for atmospheric testing of U.S. nuclear weapons. Beta dose and ..gamma..-ray exposure measurements were made on two islands of the Enewetak Atoll during July-August 1976 to determine the ..beta.. and low energy ..gamma..-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a ..beta..-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to ..beta..- or low energy ..gamma..-contribution. The contribution at any particular site, however, is reduced by vegetation. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey. Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the ..beta..'s or low energy ..gamma..'s, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

  9. beta- and gamma-Comparative dose estimates on Eniwetok Atoll

    Energy Technology Data Exchange (ETDEWEB)

    Crase, K.W.; Gudiksen, P.H.; Robison, W.L.

    1982-05-01

    Eniwetok Atoll is one of the Pacific atolls used for atmospheric testing of U.S. nuclear weapons. Beta dose and gamma-ray exposure measurements were made on two islands of the Eniwetok Atoll during July-August 1976 to determine the beta and low energy gamma-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a beta-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to beta- or low energy gamma-contribution. The contribution at any particular site, however, is somewhat dependent on ground cover, since a minimal amount of vegetation will reduce it significantly from that over bare soil, but thick stands of vegetation have little effect on any further reductions. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey (En73). Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the beta's or low energy gamma's, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

  10. The points for attention in retrospective personal dose estimate

    International Nuclear Information System (INIS)

    Wang Wuan

    1994-01-01

    The points which the attention should be paid to in the retrospective personal dose estimate are discussed. They are representative of the dose data, truthfulness of the operation history, accuracy of the man-hour statistics, and rationality of the parameters selection

  11. Estimation of staff doses in complex radiological examinations using a Monte Carlo computer code

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2007-01-01

    The protection of medical personnel in interventional radiology is an important issue of radiological protection. The irradiation of the worker is largely non-uniform, and a large part of his body is shielded by a lead apron. The estimation of effective dose (E) under these conditions is difficult and several approaches are used to estimate effective dose involving such a protective apron. This study presents a summary from an extensive series of simulations to determine scatter-dose distribution around the patient and staff effective dose from personal dosimeter readings. The influence of different parameters (like beam energy and size, patient size, irradiated region, worker position and orientation) on the staff doses has been determined. Published algorithms that combine readings of an unshielded and a shielded dosimeter to estimate effective dose have been applied and a new algorithm, that gives more accurate dose estimates for a wide range of situations was proposed. A computational approach was used to determine the dose distribution in the worker's body. The radiation transport and energy deposition was simulated using the MCNP4B code. The human bodies of the patient and radiologist were generated with the Body Builder anthropomorphic model-generating tool. The radiologist is protected with a lead apron (0.5 mm lead equivalent in the front and 0.25 mm lead equivalent in the back and sides) and a thyroid collar (0.35 mm lead equivalent). The lower-arms of the worker were folded to simulate the arms position during clinical examinations. This realistic situation of the folded arms affects the effective dose to the worker. Depending on the worker position and orientation (and of course the beam energy), the difference can go up to 25 percent. A total of 12 Hp(10) dosimeters were positioned above and under the lead apron at the neck, chest and waist levels. Extra dosimeters for the skin dose were positioned at the forehead, the forearms and the front surface of

  12. Skin entrance dose for digital and film radiography in Korean dental schools

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Eun Sang; Choi, Kun Ho; Kim, Min Gyu; Lim, Hoi Jeong; Yoon, Suk Ja; Kang, Byung Cheol [Chonnam National University College of Medicine, Gwangju (Korea, Republic of)

    2005-12-15

    This study was aimed to compare skin entrance dose of digital radiography with that of film radiography and to show the dose reduction achievement with digital systems at 11 dental schools in Korea. Forty six intraoral radiographic systems in 11 dental schools were included in this study. Digital sensors were used in 33 systems and film was used in 13 systems. Researchers and the volunteer visited 11 dental schools in Korea. Researchers asked the radiologic technician at each school to set the exposure parameters and aiming the x-ray tube for the peri apical view of the mandibular molar of the volunteer. The skin entrance doses were measured at the same exposure parameters and distance by the technician for each system with a dosimeter (Multi-O-Meter; Unifors instruments, Billdal, Sweden). The median dose was 491.2 {mu}Gy for digital radiography and 1,205.0 {mu}Gy for film radiography. The skin entrance dose in digital radiography was significantly lower than that of film radiography (p<0.05). Fifty-nine percent skin entrance dose reduction with digital peri apical radiography was achieved over the film radiography in Korean dental schools.

  13. Skin entrance dose for digital and film radiography in Korean dental schools

    International Nuclear Information System (INIS)

    Cho, Eun Sang; Choi, Kun Ho; Kim, Min Gyu; Lim, Hoi Jeong; Yoon, Suk Ja; Kang, Byung Cheol

    2005-01-01

    This study was aimed to compare skin entrance dose of digital radiography with that of film radiography and to show the dose reduction achievement with digital systems at 11 dental schools in Korea. Forty six intraoral radiographic systems in 11 dental schools were included in this study. Digital sensors were used in 33 systems and film was used in 13 systems. Researchers and the volunteer visited 11 dental schools in Korea. Researchers asked the radiologic technician at each school to set the exposure parameters and aiming the x-ray tube for the peri apical view of the mandibular molar of the volunteer. The skin entrance doses were measured at the same exposure parameters and distance by the technician for each system with a dosimeter (Multi-O-Meter; Unifors instruments, Billdal, Sweden). The median dose was 491.2 μGy for digital radiography and 1,205.0 μGy for film radiography. The skin entrance dose in digital radiography was significantly lower than that of film radiography (p<0.05). Fifty-nine percent skin entrance dose reduction with digital peri apical radiography was achieved over the film radiography in Korean dental schools.

  14. Changing Default Fluoroscopy Equipment Settings Decreases Entrance Skin Dose in Patients.

    Science.gov (United States)

    Canales, Benjamin K; Sinclair, Lindsay; Kang, Diana; Mench, Anna M; Arreola, Manuel; Bird, Vincent G

    2016-04-01

    Proper fluoroscopic education and protocols may reduce the patient radiation dose but few prospective studies in urology have been performed. Using optically stimulated luminescent dosimeters we tested whether fluoroscopy time and/or entrance skin dose would decrease after educational and radiation reduction protocols. At default manufacturer settings fluoroscopy time and entrance skin dose were prospectively measured using optically stimulated luminescent dosimeters in patients undergoing ureteroscopy, retrograde pyelogram/stent or percutaneous nephrolithotomy with access for stone disease. A validated radiation safety competency test was administered to urology faculty and residents before and after web based, hands-on fluoroscopy training. Default fluoroscopy settings were changed from continuous to intermittent pulse rate and from standard to half-dose output. Fluoroscopy time and entrance skin dose were then measured again. The cohorts of 44 pre-protocol and 50 post-protocol patients with stones were similarly matched. The change in mean fluoroscopy time and entrance skin dose from pre-protocol to post-protocol was -0.6 minutes and -11.6 mGy (33%) for percutaneous nephrolithotomy (p = 0.62 and default settings to intermittent pulse rate (12 frames per second) and half-dose lowered the entrance skin dose by 30% across all endourology patients but most significantly during percutaneous nephrolithotomy. To limit patient radiation exposure fluoroscopy default settings should be decreased before all endourology procedures and image equipment manufacturers should consider lowering standard default renal settings. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  15. Estimation of inhalation doses from airborne releases using gross monitors

    International Nuclear Information System (INIS)

    Goldstein, N.P.

    1978-01-01

    Monitoring programs at most nuclear facilities involve continuous gross measurements supplemented by periodic isotopic analyses of release samples. The isotopic measurements are required to accurately assess the potential dose from the various effluent streams, but in between these measurements, one depends on the gross monitors to provide approximate indications of the dose. The effluent streams release a variety of nuclides, each with its own dose factor. This means that the relationship between the counting rate in a gross monitor and the potential dose of the effluent being monitored will depend on the isotopic composition of this release. If this composition changes, then the dose indicated by the gross monitor (calibrated for the original group of isotopes) may be significantly in error. The problem of indicating inhalation doses from gross monitoring of airborne releases is considered. In order for this type of monitor to accurately indicate dose, regardless of the isotopic makeup of a release, the analysis shows that its response to each isotope should be proportional to the dose factor of that isotope. These ideas are applied to the monitoring of air particulates using gross beta and gross gamma monitors. The study shows that the former more closely satisfies this condition and as a result, satisfactorily indicates the actual dose from reactor effluents, as determined from detailed isotopic data published in the literature. On the other hand, the gross gamma monitor, with its poorer fit to the condition, provided less than satisfactory accuracy in its dose estimates. In addition, a variety of other mathematical response functions were considered but their dose estimation capabilities were not much better than the straight beta response. The study shows that reasonably accurate dose estimates can be made using properly selected gross monitors, but that significant errors can result with improper ones. (author)

  16. Simplification of an MCNP model designed for dose rate estimation

    Science.gov (United States)

    Laptev, Alexander; Perry, Robert

    2017-09-01

    A study was made to investigate the methods of building a simplified MCNP model for radiological dose estimation. The research was done using an example of a complicated glovebox with extra shielding. The paper presents several different calculations for neutron and photon dose evaluations where glovebox elements were consecutively excluded from the MCNP model. The analysis indicated that to obtain a fast and reasonable estimation of dose, the model should be realistic in details that are close to the tally. Other details may be omitted.

  17. Simplification of an MCNP model designed for dose rate estimation

    Directory of Open Access Journals (Sweden)

    Laptev Alexander

    2017-01-01

    Full Text Available A study was made to investigate the methods of building a simplified MCNP model for radiological dose estimation. The research was done using an example of a complicated glovebox with extra shielding. The paper presents several different calculations for neutron and photon dose evaluations where glovebox elements were consecutively excluded from the MCNP model. The analysis indicated that to obtain a fast and reasonable estimation of dose, the model should be realistic in details that are close to the tally. Other details may be omitted.

  18. Collective effective dose equivalent, population doses and risk estimates from occupational exposures in Japan

    International Nuclear Information System (INIS)

    Maruyama, Takashi; Nishizawa, Kanae; Kumamoto, Yoshikazu; Iwai, Kazuo; Mase, Naomichi.

    1993-01-01

    Collective dose equivalent and population dose from occupational exposures in Japan, 1988 were estimated on the basis of a nationwide survey. The survey was conducted on annual collective dose equivalents by sex, age group and type of radiation work for about 0.21 million workers except for the workers in nuclear power stations. The data on the workers in nuclear power stations were obtained from the official report of the Japan Nuclear Safety Commission. The total number of workers including nuclear power stations was estimated to be about 0.26 million. Radiation works were subdivided as follows: medical works including dental; non-atomic energy industry; research and education; atomic energy industry and nuclear power station. For the determination of effective dose equivalent and population dose, organ or tissue doses were measured with a phantom experiment. The resultant doses were compared with the doses previously calculated using a chord length technique and with data from ICRP publications. The annual collective effective dose equivalent were estimated to be about 21.94 person·Sv for medical workers, 7.73 person·Sv for industrial workers, 0.75 person·Sv for research and educational workers, 2.48 person·Sv for atomic energy industry and 84.4 person ·Sv for workers in nuclear power station. The population doses were calculated to be about 1.07 Sv for genetically significant dose, 0.89 Sv for leukemia significant dose and 0.42 Sv for malignant significant dose. The population risks were estimated using these population doses. (author)

  19. The response of mouse skin to multiple small doses of radiation

    International Nuclear Information System (INIS)

    Denekamp, J.; Harris, S.R.

    1975-01-01

    The response of mouse skin has been tested by irradiating the foot of albino mice and scoring erythema and desquamation during the following month. Multiple small doses of 150, 250 and 350 rad have been given 'daily', and the test dose necessary to achieve a given reaction has been determined one day after the last small fraction. This test dose has been compared with the single dose necessary to produce the same reaction level in previously untreated mice, in order to determine the ratio of the slopes of the dose-response curve at low and high doses: Slope ratio = (single dose - test dose)/total fractionated priming dose. In three separate experiments the slope ratio decreased as the dose per fraction was reduced from 350 to 150 rad. This conflicts with the data of Dutreix et al, who found a constant slope ratio over this dose range. The present data are compared with those obtained by Denekamp using 4, 9 and 14 fractions of 300 rad and by Douglas et al, using the same experimental technique, over the dose range 45 to 200 rad/fraction. In addition, the results from multifraction experiments in which equal dose increments were administered until the requisite skin reaction was achieved are also analysed in terms of their slope ratio (Fowler et al. Douglas et al). When all these results are plotted it is impossible to be sure whether the slope ratio is decreasing over the range 300 to 45 rad per fraction, although it seems likely. Most of the values at low doses lie in the range 0.15 to 0.25, indicating that at low doses the radiation is only 15 to 25% as effective per rad in causing cell death as at higher doses. (author)

  20. Transmission dose estimation algorithm for in vivo dosimetry

    International Nuclear Information System (INIS)

    Yun, Hyong Geun; Shin, Kyo Chul; Huh, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan; Lee, Hyoung Koo

    2002-01-01

    Measurement of transmission dose is useful for in vivo dosimetry of QA purpose. The objective of this study is to develope an algorithm for estimation of tumor dose using measured transmission dose for open radiation field. Transmission dose was measured with various field size (FS), phantom thickness (Tp), and phantom chamber distance (PCD) with an acrylic phantom for 6 MV and 10 MV X-ray. Source to chamber distance (SCD) was set to 150 cm. Measurement was conducted with a 0.6 cc Farmer type ion chamber. Using measured data and regression analysis, an algorithm was developed for estimation of expected reading of transmission dose. Accuracy of the algorithm was tested with flat solid phantom with various settings. The algorithm consisted of quadratic function of log(A/P) (where A/P is area-perimeter ratio) and tertiary function of PCD. The algorithm could estimate dose with very high accuracy for open square field, with errors within ±0.5%. For elongated radiation field, the errors were limited to ±1.0%. The developed algorithm can accurately estimate the transmission dose in open radiation fields with various treatment settings

  1. Transmission dose estimation algorithm for in vivo dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Hyong Geun; Shin, Kyo Chul [Dankook Univ., Seoul (Korea, Republic of); Huh, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan [Seoul National Univ., Seoul (Korea, Republic of); Lee, Hyoung Koo [Catholic Univ., Seoul (Korea, Republic of)

    2002-07-01

    Measurement of transmission dose is useful for in vivo dosimetry of QA purpose. The objective of this study is to develope an algorithm for estimation of tumor dose using measured transmission dose for open radiation field. Transmission dose was measured with various field size (FS), phantom thickness (Tp), and phantom chamber distance (PCD) with an acrylic phantom for 6 MV and 10 MV X-ray. Source to chamber distance (SCD) was set to 150 cm. Measurement was conducted with a 0.6 cc Farmer type ion chamber. Using measured data and regression analysis, an algorithm was developed for estimation of expected reading of transmission dose. Accuracy of the algorithm was tested with flat solid phantom with various settings. The algorithm consisted of quadratic function of log(A/P) (where A/P is area-perimeter ratio) and tertiary function of PCD. The algorithm could estimate dose with very high accuracy for open square field, with errors within {+-}0.5%. For elongated radiation field, the errors were limited to {+-}1.0%. The developed algorithm can accurately estimate the transmission dose in open radiation fields with various treatment settings.

  2. Considerations on absorbed dose estimates based on different β-dose point kernels in internal dosimetry

    International Nuclear Information System (INIS)

    Uchida, Isao; Yamada, Yasuhiko; Yamashita, Takashi; Okigaki, Shigeyasu; Oyamada, Hiyoshimaru; Ito, Akira.

    1995-01-01

    In radiotherapy with radiopharmaceuticals, more accurate estimates of the three-dimensional (3-D) distribution of absorbed dose is important in specifying the activity to be administered to patients to deliver a prescribed absorbed dose to target volumes without exceeding the toxicity limit of normal tissues in the body. A calculation algorithm for the purpose has already been developed by the authors. An accurate 3-D distribution of absorbed dose based on the algorithm is given by convolution of the 3-D dose matrix for a unit cubic voxel containing unit cumulated activity, which is obtained by transforming a dose point kernel into a 3-D cubic dose matrix, with the 3-D cumulated activity distribution given by the same voxel size. However, beta-dose point kernels affecting accurate estimates of the 3-D absorbed dose distribution have been different among the investigators. The purpose of this study is to elucidate how different beta-dose point kernels in water influence on the estimates of the absorbed dose distribution due to the dose point kernel convolution method by the authors. Computer simulations were performed using the MIRD thyroid and lung phantoms under assumption of uniform activity distribution of 32 P. Using beta-dose point kernels derived from Monte Carlo simulations (EGS-4 or ACCEPT computer code), the differences among their point kernels gave little differences for the mean and maximum absorbed dose estimates for the MIRD phantoms used. In the estimates of mean and maximum absorbed doses calculated using different cubic voxel sizes (4x4x4 mm and 8x8x8 mm) for the MIRD thyroid phantom, the maximum absorbed doses for the 4x4x4 mm-voxel were estimated approximately 7% greater than the cases of the 8x8x8 mm-voxel. They were found in every beta-dose point kernel used in this study. On the other hand, the percentage difference of the mean absorbed doses in the both voxel sizes for each beta-dose point kernel was less than approximately 0.6%. (author)

  3. Estimation of dose and exposure at sentinel node study

    International Nuclear Information System (INIS)

    Skopljak, A.; Kucukalic-Selimovic, E.; Beslic, N.; Begic, A.; Begovic-Hadzimuratovic, S.; Drazeta, Z.; Beganovic, A.

    2005-01-01

    The purpose of this study was to estimate the dose end exposure in staff involved in sentinel node procedure for breast cancer patients. The Institute of Nuclear Medicine in Sarajevo uses a protocol for lymphoscintigraphy of the sentinel node whereby 13 MBq of 9 9mT c nanocoll are used. In this study, we measured radiation doses and exposure of a nuclear medicine physician and a technologist, as well as a surgeon performing sentinel node lymphoscintigraphy and biopsy. Dose and exposure were calculated using the equation in which we have gamma constant for 9 9mT c. Calculations were made for different times of exposure and distance. In Table 1. we estimated the dose and exposure during sentinel node study. Radiation levels were very low and the most exposed hospital staff performing sentinel node study were nuclear medicine physicians. The doses on the hands of surgeons were negligible 8 hours after exposure.(author)

  4. The minimal melanogenesis dose/minimal erythema dose ratio declines with increasing skin pigmentation using solar simulator and narrowband ultraviolet B exposure

    DEFF Research Database (Denmark)

    Ravnbak, Mette H; Philipsen, Peter A; Wulf, Hans Christian

    2010-01-01

    To investigate the relation between pre-exposure skin pigmentation and the minimal melanogenesis dose (MMD)/minimal erythema dose (MED) ratio after a single narrowband ultraviolet B (nUVB) and solar simulator (Solar) exposure.......To investigate the relation between pre-exposure skin pigmentation and the minimal melanogenesis dose (MMD)/minimal erythema dose (MED) ratio after a single narrowband ultraviolet B (nUVB) and solar simulator (Solar) exposure....

  5. Relative potency estimation for synthetic petroleum skin carcinogens.

    OpenAIRE

    Holland, J M; Wolf, D A; Clark, B R

    1981-01-01

    A procedure for quantitative analysis of skin carcinogenesis data, for the purpose of establishing carcinogenic potency, has been applied to observations obtained from C3H mice exposed continuously to synthetic and natural petroleums. The importance of total polynuclear aromatic (PNA) content to the skin carcinogenic activity of the crude materials was also examined. Of three synthetic petroleums evaluated, all were shown capable of inducing skin neoplasms within a two-year exposure period. U...

  6. Fractional sunburn threshold UVR doses generate equivalent vitamin D and DNA damage in skin types I-VI, but with epidermal DNA damage gradient correlated to skin darkness.

    Science.gov (United States)

    Shih, Barbara B; Farrar, Mark D; Cooke, Marcus S; Osman, Joanne; Langton, Abigail K; Kift, Richard; Webb, Ann R; Berry, Jacqueline L; Watson, Rachel E B; Vail, Andy; de Gruijl, Frank R; Rhodes, Lesley E

    2018-05-03

    Public health guidance recommends limiting sun-exposure to sub-sunburn levels, but it's unknown whether these can gain vitamin D (for musculoskeletal health) whilst avoiding epidermal DNA damage (initiates skin cancer). Well-characterised healthy humans of all skin types (I-VI; lightest to darkest skin) were exposed to a low dose-series of solar simulated UVR of 20-80% their individual sunburn threshold dose (minimal erythemal dose, MED). Significant UVR dose-responses were seen for serum 25(OH)D and whole epidermal CPD, with as little as 0.2 MED concurrently producing 25(OH)D and CPD. Notably, fractional MEDs generated equivalent levels of whole epidermal CPD and 25(OH)D across all skin types. Crucially, we demonstrated an epidermal gradient of CPD formation strongly correlated with skin darkness (r=0.74; Pskin types, ranging from darkest skin, where high CPD levels occurred superficially with none in the germinative basal layer, through to lightest skin where CPD were induced evenly across the epidermal depth. Darker skin people can be encouraged to utilise sub-sunburn UVR-exposure to enhance their vitamin D. In lighter skin people, basal cell damage occurs concurrent with vitamin D synthesis at exquisitely low UVR levels, providing an explanation for their high skin cancer incidence; greater caution is required. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  7. A Web-Based System for Bayesian Benchmark Dose Estimation.

    Science.gov (United States)

    Shao, Kan; Shapiro, Andrew J

    2018-01-11

    Benchmark dose (BMD) modeling is an important step in human health risk assessment and is used as the default approach to identify the point of departure for risk assessment. A probabilistic framework for dose-response assessment has been proposed and advocated by various institutions and organizations; therefore, a reliable tool is needed to provide distributional estimates for BMD and other important quantities in dose-response assessment. We developed an online system for Bayesian BMD (BBMD) estimation and compared results from this software with U.S. Environmental Protection Agency's (EPA's) Benchmark Dose Software (BMDS). The system is built on a Bayesian framework featuring the application of Markov chain Monte Carlo (MCMC) sampling for model parameter estimation and BMD calculation, which makes the BBMD system fundamentally different from the currently prevailing BMD software packages. In addition to estimating the traditional BMDs for dichotomous and continuous data, the developed system is also capable of computing model-averaged BMD estimates. A total of 518 dichotomous and 108 continuous data sets extracted from the U.S. EPA's Integrated Risk Information System (IRIS) database (and similar databases) were used as testing data to compare the estimates from the BBMD and BMDS programs. The results suggest that the BBMD system may outperform the BMDS program in a number of aspects, including fewer failed BMD and BMDL calculations and estimates. The BBMD system is a useful alternative tool for estimating BMD with additional functionalities for BMD analysis based on most recent research. Most importantly, the BBMD has the potential to incorporate prior information to make dose-response modeling more reliable and can provide distributional estimates for important quantities in dose-response assessment, which greatly facilitates the current trend for probabilistic risk assessment. https://doi.org/10.1289/EHP1289.

  8. Chest X ray effective doses estimation in computed radiography

    International Nuclear Information System (INIS)

    Abdalla, Esra Abdalrhman Dfaalla

    2013-06-01

    Conventional chest radiography is technically difficult because of wide in tissue attenuations in the chest and limitations of screen-film systems. Computed radiography (CR) offers a different approach utilizing a photostimulable phosphor. photostimulable phosphors overcome some image quality limitations of chest imaging. The objective of this study was to estimate the effective dose in computed radiography at three hospitals in Khartoum. This study has been conducted in radiography departments in three centres Advanced Diagnostic Center, Nilain Diagnostic Center, Modern Diagnostic Center. The entrance surface dose (ESD) measurement was conducted for quality control of x-ray machines and survey of operators experimental techniques. The ESDs were measured by UNFORS dosimeter and mathematical equations to estimate patient doses during chest X rays. A total of 120 patients were examined in three centres, among them 62 were males and 58 were females. The overall mean and range of patient dosed was 0.073±0.037 (0.014-0.16) mGy per procedure while the effective dose was 3.4±01.7 (0.6-7.0) mSv per procedure. This study compared radiation doses to patients radiographic examinations of chest using computed radiology. The radiation dose was measured in three centres in Khartoum- Sudan. The results of the measured effective dose showed that the dose in chest radiography was lower in computed radiography compared to previous studies.(Author)

  9. Estimates of bias and uncertainty in recorded external dose

    International Nuclear Information System (INIS)

    Fix, J.J.; Gilbert, E.S.; Baumgartner, W.V.

    1994-10-01

    A study is underway to develop an approach to quantify bias and uncertainty in recorded dose estimates for workers at the Hanford Site based on personnel dosimeter results. This paper focuses on selected experimental studies conducted to better define response characteristics of Hanford dosimeters. The study is more extensive than the experimental studies presented in this paper and includes detailed consideration and evaluation of other sources of bias and uncertainty. Hanford worker dose estimates are used in epidemiologic studies of nuclear workers. A major objective of these studies is to provide a direct assessment of the carcinogenic risk of exposure to ionizing radiation at low doses and dose rates. Considerations of bias and uncertainty in the recorded dose estimates are important in the conduct of this work. The method developed for use with Hanford workers can be considered an elaboration of the approach used to quantify bias and uncertainty in estimated doses for personnel exposed to radiation as a result of atmospheric testing of nuclear weapons between 1945 and 1962. This approach was first developed by a National Research Council (NRC) committee examining uncertainty in recorded film badge doses during atmospheric tests (NRC 1989). It involved quantifying both bias and uncertainty from three sources (i.e., laboratory, radiological, and environmental) and then combining them to obtain an overall assessment. Sources of uncertainty have been evaluated for each of three specific Hanford dosimetry systems (i.e., the Hanford two-element film dosimeter, 1944-1956; the Hanford multi-element film dosimeter, 1957-1971; and the Hanford multi-element TLD, 1972-1993) used to estimate personnel dose throughout the history of Hanford operations. Laboratory, radiological, and environmental sources of bias and uncertainty have been estimated based on historical documentation and, for angular response, on selected laboratory measurements

  10. Estimation of organ and effective dose due to Compton backscatter security scans

    International Nuclear Information System (INIS)

    Hoppe, Michael E.; Schmidt, Taly Gilat

    2012-01-01

    Purpose: To estimate organ and effective radiation doses due to backscatter security scanners using Monte Carlo simulations and a voxelized phantom set. Methods: Voxelized phantoms of male and female adults and children were used with the GEANT4 toolkit to simulate a backscatter security scan. The backscatter system was modeled based on specifications available in the literature. The simulations modeled a 50 kVp spectrum with 1.0 mm-aluminum-equivalent filtration and a previously measured exposure of approximately 4.6 μR at 30 cm from the source. Photons and secondary interactions were tracked from the source until they reached zero kinetic energy or exited from the simulation’s boundaries. The energy deposited in the phantoms’ respective organs was tallied and used to calculate total organ dose and total effective dose for frontal, rear, and full scans with subjects located 30 and 75 cm from the source. Results: For a full screen, all phantoms’ total effective doses were below the established 0.25 μSv standard, with an estimated maximum total effective dose of 0.07 μSv for full screen of a male child. The estimated maximum organ dose due to a full screen was 1.03 μGy, deposited in the adipose tissue of the male child phantom when located 30 cm from the source. All organ dose estimates had a coefficient of variation of less than 3% for a frontal scan and less than 11% for a rear scan. Conclusions: Backscatter security scanners deposit dose in organs beyond the skin. The effective dose is below recommended standards set by the Health Physics Society (HPS) and the American National Standards Institute (ANSI) assuming the system provides a maximum exposure of approximately 4.6 μR at 30 cm.

  11. Underprediction of human skin erythema at low doses per fraction by the linear quadratic model

    International Nuclear Information System (INIS)

    Hamilton, Christopher S.; Denham, James W.; O'Brien, Maree; Ostwald, Patricia; Kron, Tomas; Wright, Suzanne; Doerr, Wolfgang

    1996-01-01

    Background and purpose. The erythematous response of human skin to radiotherapy has proven useful for testing the predictions of the linear quadratic (LQ) model in terms of fractionation sensitivity and repair half time. No formal investigation of the response of human skin to doses less than 2 Gy per fraction has occurred. This study aims to test the validity of the LQ model for human skin at doses ranging from 0.4 to 5.2 Gy per fraction. Materials and methods. Complete erythema reaction profiles were obtained using reflectance spectrophotometry in two patient populations: 65 patients treated palliatively with 5, 10, 12 and 20 daily treatment fractions (varying thicknesses of bolus, various body sites) and 52 patients undergoing prostatic irradiation for localised carcinoma of the prostate (no bolus, 30-32 fractions). Results and conclusions. Gender, age, site and prior sun exposure influence pre- and post-treatment erythema values independently of dose administered. Out-of-field effects were also noted. The linear quadratic model significantly underpredicted peak erythema values at doses less than 1.5 Gy per fraction. This suggests that either the conventional linear quadratic model does not apply for low doses per fraction in human skin or that erythema is not exclusively initiated by radiation damage to the basal layer. The data are potentially explained by an induced repair model

  12. Methodology for Estimating Ingestion Dose for Emergency Response at SRS

    CERN Document Server

    Simpkins, A A

    2002-01-01

    At the Savannah River Site (SRS), emergency response models estimate dose for inhalation and ground shine pathways. A methodology has been developed to incorporate ingestion doses into the emergency response models. The methodology follows a two-phase approach. The first phase estimates site-specific derived response levels (DRLs) which can be compared with predicted ground-level concentrations to determine if intervention is needed to protect the public. This phase uses accepted methods with little deviation from recommended guidance. The second phase uses site-specific data to estimate a 'best estimate' dose to offsite individuals from ingestion of foodstuffs. While this method deviates from recommended guidance, it is technically defensibly and more realistic. As guidance is updated, these methods also will need to be updated.

  13. Biological dose estimation for accidental supra-high dose gamma-ray exposure

    International Nuclear Information System (INIS)

    Chen, Y.; Yan, X.K.; Du, J.; Wang, Z.D.; Zhang, X.Q.; Zeng, F.G.; Zhou, P.K.

    2011-01-01

    To correctly estimate the biological dose of victims accidentally exposed to a very high dose of 60 Co gamma-ray, a new dose-effect curve of chromosomal dicentrics/multicentrics and rings in the supra-high dose range was established. Peripheral blood from two healthy men was irradiated in vitro with doses of 60 Co gamma-rays ranging from 6 to 22 Gy at a dose rate of 2.0 Gy/min. Lymphocytes were concentrated, cultured and harvested at 52 h, 68 h and 72 h. The numbers of dic + r were counted. The dose-effect curves were established and validated using comparisons with doses from the Tokai-mura accident and were then applied to two victims of supra-high dose exposure accident. The results indicated that there were no significant differences in chromosome aberration frequency among the different culture times from 52 h to 72 h. The 6-22 Gy dose-effect curve was fitted to a linear quadratic model Y = -2.269 + 0.776D - 7.868 x l0 -3 D 2 . Using this mathematic model, the dose estimates were similar to data from Tokai-mura which were estimated by PCC ring. Whole body average doses of 9.7 Gy and 18.1 Gy for two victims in the Jining accident were satisfactorily given. We established and successfully applied a new dose-effect curve of chromosomal dicentrics plus ring (dic + r) after 6-22 Gy γ-irradiation from a supra-high dose 60 Co gamma-ray accident.

  14. Dose-response curve estimation: a semiparametric mixture approach.

    Science.gov (United States)

    Yuan, Ying; Yin, Guosheng

    2011-12-01

    In the estimation of a dose-response curve, parametric models are straightforward and efficient but subject to model misspecifications; nonparametric methods are robust but less efficient. As a compromise, we propose a semiparametric approach that combines the advantages of parametric and nonparametric curve estimates. In a mixture form, our estimator takes a weighted average of the parametric and nonparametric curve estimates, in which a higher weight is assigned to the estimate with a better model fit. When the parametric model assumption holds, the semiparametric curve estimate converges to the parametric estimate and thus achieves high efficiency; when the parametric model is misspecified, the semiparametric estimate converges to the nonparametric estimate and remains consistent. We also consider an adaptive weighting scheme to allow the weight to vary according to the local fit of the models. We conduct extensive simulation studies to investigate the performance of the proposed methods and illustrate them with two real examples. © 2011, The International Biometric Society.

  15. Research and development of a beta skin-dose monitor using silicon detectors

    International Nuclear Information System (INIS)

    Chung Manho.

    1991-01-01

    The purpose of the research is to develop improved ways to computer and measure the beta skin dose. Beta spectra for the various sources were calculated based on the Fermi beta decay theory. The calculated average energies of the spectra agreed with the literature values within 6%. Monte Carlo electron transport codes have been developed for use on microcomputers. The one-dimensional code ZEBRA has been converted to a microcomputer version called Eltran2 which runs on the Macintosh or any IBM compatible microcomputers. Eltran2 has then been modified into a two-dimensional program called Eltran3. Using Eltran2 and Eltran3, different source distributions and the hot particle dose have been studied. It has been found that the VARSKIN code overestimates the skin dose from hot particles by about 10 to 40% in comparison with Eltran3 calculations, because the VARSKIN code is based on the data tables for an unbounded medium. An ion-implanted silicon detector was selected because of its small size, high sensitivity, and low leakage current. To cover a wide range of dose rate, both the pulse and current mode operations of the silicon detector were used, with an overlap of one order of magnitude in the measurable dose rate ranges. By using a gradient shield of about 7 mg/cm 2 on the detector, dose gradient measurements have been performed. Five 60 Co hot particles received from GPU Nuclear Corporation have been measured by the silicon detector and the measurements agreed well with Eltran3 calculations. In the pulse mode, variation of the depletion depth of the silicon detector due to the changes of bias voltage was confirmed. Based on this research, a prototype beta skin dose monitor has been constructed. The device includes an 8-bit analogue-to-digital converter and a Z-80 microprocessor with a machine-coded program, to calculate the skin dose

  16. Dose estimate of exposure to radioisotopes in molecular and cellular biology

    International Nuclear Information System (INIS)

    Onado, C.; Faretta, M.; Ubezio, P.

    1999-01-01

    A method for prospectively evaluating the annual equivalent doses and effective dose to biomedical researchers working with unsealed radioisotopes, and their classification, is presented here. Simplified formulae relate occupational data to a reasonable overestimate of the annual effective dose, and the equivalent doses to the hands and to the skin. The procedure, up to the classification of personnel and laboratories, can be made fully automatic, using a common spreadsheet on a personal computer. The method is based on occupational data, accounting for the amounts of each radioisotope used by a researcher, the time of exposure and the overall amounts employed in the laboratories where experiments are performed. The former data serve to forecast a contribution to the dose arising from a researcher's own work, the latter to a forecast of an 'environmental' contribution deriving simply from the presence in a laboratory where other people are working with radioisotopes. The estimates of the doses due to one's own radioisotope handling and to 'environment' were corrected for accidental exposure, considered as a linear function of the manipulated activity or of the time spent in the laboratories respectively, and summed up to give the effective dose. The effective dose associated with some common experiments in molecular and cellular biology is pre-evaluated by this method. (author)

  17. Characterization of a MOSkin detector for in vivo skin dose measurements during interventional radiology procedures

    Energy Technology Data Exchange (ETDEWEB)

    Safari, M. J.; Wong, J. H. D.; Ng, K. H., E-mail: ngkh@um.edu.my [Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia and University of Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603 (Malaysia); Jong, W. L. [Clinical Oncology Unit, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603 (Malaysia); Cutajar, D. L.; Rosenfeld, A. B. [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2015-05-15

    Purpose: The MOSkin is a MOSFET detector designed especially for skin dose measurements. This detector has been characterized for various factors affecting its response for megavoltage photon beams and has been used for patient dose measurements during radiotherapy procedures. However, the characteristics of this detector in kilovoltage photon beams and low dose ranges have not been studied. The purpose of this study was to characterize the MOSkin detector to determine its suitability for in vivo entrance skin dose measurements during interventional radiology procedures. Methods: The calibration and reproducibility of the MOSkin detector and its dependency on different radiation beam qualities were carried out using RQR standard radiation qualities in free-in-air geometry. Studies of the other characterization parameters, such as the dose linearity and dependency on exposure angle, field size, frame rate, depth-dose, and source-to-surface distance (SSD), were carried out using a solid water phantom under a clinical x-ray unit. Results: The MOSkin detector showed good reproducibility (94%) and dose linearity (99%) for the dose range of 2 to 213 cGy. The sensitivity did not significantly change with the variation of SSD (±1%), field size (±1%), frame rate (±3%), or beam energy (±5%). The detector angular dependence was within ±5% over 360° and the dose recorded by the MOSkin detector in different depths of a solid water phantom was in good agreement with the Markus parallel plate ionization chamber to within ±3%. Conclusions: The MOSkin detector proved to be reliable when exposed to different field sizes, SSDs, depths in solid water, dose rates, frame rates, and radiation incident angles within a clinical x-ray beam. The MOSkin detector with water equivalent depth equal to 0.07 mm is a suitable detector for in vivo skin dosimetry during interventional radiology procedures.

  18. Dose Estimation from Daily and Weekly Dosimetry Data

    Energy Technology Data Exchange (ETDEWEB)

    Ostrouchov, G.

    2001-11-16

    Statistical analyses of data from epidemiologic studies of workers exposed to radiation have been based on recorded annual radiation doses (yearly dose of record). It is usually assumed that the dose values are known exactly, although it is generally recognized that the data contain uncertainty due to measurement error and bias. In our previous work with weekly data, a probability distribution was used to describe an individual's dose during a specific period of time and statistical methods were developed for estimating it from weekly film dosimetry data. This study showed that the yearly dose of record systematically underestimates doses for Oak Ridge National Laboratory (ORNL) workers. This could result in biased estimates of dose-response coefficients and their standard errors. The results of this evaluation raise serious questions about the suitability of the yearly dose of record for direct use in low-dose studies of nuclear industry workers. Here, we extend our previous work to use full information in Pocket meter data and develop the Data Synthesis for Individual Dose Estimation (DSIDE) methodology. Although the DSIDE methodology in this study is developed in the context of daily and weekly data to produce a cumulative yearly dose estimate, in principle it is completely general and can be extended to other time period and measurement combinations. The new methodology takes into account the ''measurement error'' that is produced by the film and pocket-meter dosimetry systems, the biases introduced by policies that lead to recording left-censored doses as zeros, and other measurement and recording practices. The DSIDE method is applied to a sample of dose histories obtained from hard copy dosimetry records at ORNL for the years 1945 to 1955. First, the rigorous addition of daily pocket-meter information shows that the negative bias is generally more severe than was reported in our work based on weekly film data only, however, the

  19. Dose Estimation from Daily and Weekly Dosimetry Data

    International Nuclear Information System (INIS)

    Ostrouchov, G.

    2001-01-01

    Statistical analyses of data from epidemiologic studies of workers exposed to radiation have been based on recorded annual radiation doses (yearly dose of record). It is usually assumed that the dose values are known exactly, although it is generally recognized that the data contain uncertainty due to measurement error and bias. In our previous work with weekly data, a probability distribution was used to describe an individual's dose during a specific period of time and statistical methods were developed for estimating it from weekly film dosimetry data. This study showed that the yearly dose of record systematically underestimates doses for Oak Ridge National Laboratory (ORNL) workers. This could result in biased estimates of dose-response coefficients and their standard errors. The results of this evaluation raise serious questions about the suitability of the yearly dose of record for direct use in low-dose studies of nuclear industry workers. Here, we extend our previous work to use full information in Pocket meter data and develop the Data Synthesis for Individual Dose Estimation (DSIDE) methodology. Although the DSIDE methodology in this study is developed in the context of daily and weekly data to produce a cumulative yearly dose estimate, in principle it is completely general and can be extended to other time period and measurement combinations. The new methodology takes into account the ''measurement error'' that is produced by the film and pocket-meter dosimetry systems, the biases introduced by policies that lead to recording left-censored doses as zeros, and other measurement and recording practices. The DSIDE method is applied to a sample of dose histories obtained from hard copy dosimetry records at ORNL for the years 1945 to 1955. First, the rigorous addition of daily pocket-meter information shows that the negative bias is generally more severe than was reported in our work based on weekly film data only, however, the amount of bias also varies

  20. A risk adjustment approach to estimating the burden of skin disease in the United States.

    Science.gov (United States)

    Lim, Henry W; Collins, Scott A B; Resneck, Jack S; Bolognia, Jean; Hodge, Julie A; Rohrer, Thomas A; Van Beek, Marta J; Margolis, David J; Sober, Arthur J; Weinstock, Martin A; Nerenz, David R; Begolka, Wendy Smith; Moyano, Jose V

    2018-01-01

    Direct insurance claims tabulation and risk adjustment statistical methods can be used to estimate health care costs associated with various diseases. In this third manuscript derived from the new national Burden of Skin Disease Report from the American Academy of Dermatology, a risk adjustment method that was based on modeling the average annual costs of individuals with or without specific diseases, and specifically tailored for 24 skin disease categories, was used to estimate the economic burden of skin disease. The results were compared with the claims tabulation method used in the first 2 parts of this project. The risk adjustment method estimated the direct health care costs of skin diseases to be $46 billion in 2013, approximately $15 billion less than estimates using claims tabulation. For individual skin diseases, the risk adjustment cost estimates ranged from 11% to 297% of those obtained using claims tabulation for the 10 most costly skin disease categories. Although either method may be used for purposes of estimating the costs of skin disease, the choice of method will affect the end result. These findings serve as an important reference for future discussions about the method chosen in health care payment models to estimate both the cost of skin disease and the potential cost impact of care changes. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  1. Hygienic estimation of population doses due to stratospheric fallout

    International Nuclear Information System (INIS)

    Marej, A.N.; Knizhnikov, V.A.

    1980-01-01

    The hygienic estimation of external and internal irradiation of the USSR population due to stratospheric global fallouts of fission products after nuclear explosions and weapon tests, is carried out. Numerical values which characterize the dose-effect dependence in the case of radiation of marrow, bone tissue and whole body are presented. Values of mean individual and population doses of irradiation due to global fallouts within 1963-1975, types of injury and the number of mortal cases due to malignant neoplasms are presented. A conclusion is made that the contribution of radiation due to stratospheric fallouts in the mortality due to malignant neoplasms is insignificant. Annual radiation doses, conditioned by global fallouts within the period of 1963-1975 constitute but several percent from the dose of radiation of the natural radiation background. Results of estimation of genetic consequences of irradiation due to atmospheric fallouts are presented

  2. Organ dose estimates for the Japanese atomic-bomb survivors

    International Nuclear Information System (INIS)

    Kerr, G.D.

    1978-10-01

    Recent studies concerning radiation risks to man by the Committee on Biological Effects of Ionizing Radiation of the National Academy of Sciences-National Research Council and the United Nations Scientific Committee on the Effects of Atomic Radiation have emphasized the need for estimates of dose to organs of the Japanese atomic-bomb survivors. Shielding of internal organs by the body has been investigated for fission-weapon gamma rays and neutrons, and ratios of mean absorbed dose in a number of organs to survivors' T65D assignments of tissue kerma in air are provided for adults. Ratios of mean absorbed dose to tissue kerma in air are provided also for the thyroid and active bone marrow of juveniles. These organ dose estimates for juveniles are of interest in studies of radiation risks due to an elevated incidence of leukemia and thyroid cancer in survivors exposed as children compared to survivors exposed as adults

  3. Skin dose from distributed radioactive sources and hot particles - Regulations and recommendations

    International Nuclear Information System (INIS)

    Porter, S.W.

    1991-01-01

    The issues concerning Beta Dosimetry, Hot Particle Dosimetry, and associated dose to skin have been highlighted since the 1979 TMI-2 accident report of the Presidential Commission. The conclusions drawn from the DOE/EML International Beta Dosimetry Symposium of 1983 are still valid. The questions of location(s) of the radiosensitive layer of human skin, the most valid method of skin dose measurement and interpretation of associated radiobiological data are still lingering. The need for improving beta calculation standards and procedures are more evident now than in 1983. This paper will discuss the newest ICRP and NCRP recommendations, as well as the regulations and guidelines from the NRC. I would expect that the draft recommendations published in this paper will be considerably changed by the time of the January, 1991 presentation of this paper

  4. The dependence of percentage depth dose on the source-to-skin ...

    African Journals Online (AJOL)

    The variation of percentage depth dose (PDD) with source-to-skin distance (SSD) for kilovoltage X-rays used in radiotherapy has been investigated. Based on physical parameters of photon fluence, absorption and scatter during interaction of radiation with tissue, a mathematical model was developed to predict the PDDs at ...

  5. Determination of entrance skin dose from diagnostic X-ray of human ...

    African Journals Online (AJOL)

    patient during x-ray examination in Federal Medical Centre, Keffi in Nasarawa state, Nigeria. Entrance skin doses (ESDs) for a common type of x-ray procedures, namely chest AP/PA (anterior/posterior) were measured. A total of 200 data were collected from patients who were exposed to diagnostic X-ray during their routine ...

  6. Evaluation of dose to skin surface contamination in the factory Juzbado of fuel elements

    International Nuclear Information System (INIS)

    Ortiz Trujillo, D.; Agustin Perez Fonseca, A.; Alejandro Fuentes, A.

    2013-01-01

    The aim of this work is previously set a simple calculation methodology applicable to the boundary conditions surrounding the environment where skin contamination may have occurred so that you can evaluate in a simple and fast way the dose that the worker is receiving while enduring such pollution. (Author)

  7. Entrance skin dose on patients undergoing X-ray examinations at ...

    African Journals Online (AJOL)

    survey was conducted on the Entrance Skin Dose (ESD) in patients undergoing X-ray examinations [Skull Postero-Anterior (PA), Skull Lateral (LAT), Chest Postero-Anterior (PA), Chest Lateral (LAT), Abdomen Antero-Posterior (AP) and Pelvis Antero-Posterior (AP)] in five hospitals/Xray centres in Yaba, Lagos State, Nigeria ...

  8. Radiation dose estimates for copper-64 citrate in man

    International Nuclear Information System (INIS)

    Crook, J.E.; Carlton, J.E.; Stabin, M.; Watson, E.

    1985-01-01

    Tumor imaging agents suitable for use with positron emission tomographs are constantly sought. We have performed studies with animal-tumor-bearing models that have demonstrated the rapid uptake of copper-64. The radiation dose estimates for man indicate that the intravenous administration of 7.0 mCi would result in radiation doses to the kidney of 9.8 to 10.5 rads with other organs receiving substantially less radiation. 5 refs., 3 tabs

  9. Radiation dose estimates for copper-64 citrate in man

    International Nuclear Information System (INIS)

    Crook, J.E.; Carlton, J.E.; Stabin, M.; Watson, E.

    1986-01-01

    Tumor imaging agents suitable for use with positron emission tomographs are constantly sought. The authors have performed studies with animal-tumor-bearing models that have demonstrated the rapid uptake of copper-64. The radiation dose estimates for man indicate that the intravenous administration of 7.0 mCi would result in radiation doses to the kidney of 9.8 to 10.5 rads with other organs receiving substantially less radiations. 5 references, 3 tables

  10. Estimation of population doses from stomach mass screening, 1975

    Energy Technology Data Exchange (ETDEWEB)

    Hashizume, T; Kato, Y; Maruyama, T [National Inst. of Radiological Sciences, Chiba (Japan); Kamata, R; Urahashi, S

    1977-06-01

    The population dose from mass photofluorography of stomach have been estimated on the basis of nation wide radiological survey. The number of photofluorographic examinations was 2.38 million for male and 1.74 million for female, with a total of 4.12 million. The gonad doses were determined with an ionization chamber, using a tissue equivalent phantom. The gonad dose for male was 10.4 mrad per examination and for female was 150 mrad per examination. The active bone marrow doses at 32 points of bone marrow in the whole body were measured with thermoluminescent dosimeter. The mean marrow dose per photofluorographic examination was 450 mrad for male and 390 mrad for female. The child expectancy factor and the leukemia significant factor were calculated based on the Vital Statistics 1975. The genetically significant dose (GSD) and per caput mean marrow dose (CMD) were calculated by the formulae presented from the United Nations Scientific Comittee of Effects of Atomic Radiation (UNSCEAR). The resultant GSD was 0.15 mrad per person per year. The CMD was 16.5 mrad per person per year. The leukemia significant dose (LSD) was determined by adopting a weight factor, that is leukemia significant factor. The resultant LSD was 14.5 mrad per person per year. These population doses were compared with those from diagnostic medical x-ray examinations in 1974.

  11. Association between cumulative radiation dose, adverse skin reactions, and changes in surface hemoglobin among women undergoing breast conserving therapy

    Directory of Open Access Journals (Sweden)

    Michael S. Chin

    2017-06-01

    Conclusion: HSI demonstrates promise in the assessment of skin dose as well as an objective measure of skin reaction. The ability to easily identify adverse skin reactions and to modify the treatment plan may circumvent the need for detrimental treatment breaks.

  12. Time improvement of photoelectric effect calculation for absorbed dose estimation

    International Nuclear Information System (INIS)

    Massa, J M; Wainschenker, R S; Doorn, J H; Caselli, E E

    2007-01-01

    Ionizing radiation therapy is a very useful tool in cancer treatment. It is very important to determine absorbed dose in human tissue to accomplish an effective treatment. A mathematical model based on affected areas is the most suitable tool to estimate the absorbed dose. Lately, Monte Carlo based techniques have become the most reliable, but they are time expensive. Absorbed dose calculating programs using different strategies have to choose between estimation quality and calculating time. This paper describes an optimized method for the photoelectron polar angle calculation in photoelectric effect, which is significant to estimate deposited energy in human tissue. In the case studies, time cost reduction nearly reached 86%, meaning that the time needed to do the calculation is approximately 1/7 th of the non optimized approach. This has been done keeping precision invariant

  13. Persistent DNA damage after high dose in vivo gamma exposure of minipig skin.

    Directory of Open Access Journals (Sweden)

    Emad A Ahmed

    Full Text Available Exposure to high doses of ionizing radiation (IR can lead to localized radiation injury of the skin and exposed cells suffer dsDNA breaks that may elicit cell death or stochastic changes. Little is known about the DNA damage response after high-dose exposure of the skin. Here, we investigate the cellular and DNA damage response in acutely irradiated minipig skin.IR-induced DNA damage, repair and cellular survival were studied in 15 cm(2 of minipig skin exposed in vivo to ~50 Co-60 γ rays. Skin biopsies of control and 4 h up to 96 days post exposure were investigated for radiation-induced foci (RIF formation using γ-H2AX, 53BP1, and active ATM-p immunofluorescence. High-dose IR induced massive γ-H2AX phosphorylation and high 53BP1 RIF numbers 4 h, 20 h after IR. As time progressed RIF numbers dropped to a low of 3-fold elevated at all subsequent time points. Replicating basal cells (Ki67+ were reduced 3 days post IR followed by increased proliferation and recovery of epidermal cellularity after 28 days.Acute high dose irradiation of minipig epidermis impaired stem cell replication and induced elevated apoptosis from 3 days onward. DNA repair cleared the high numbers of DBSs in skin cells, while RIFs that persisted in <1% cells marked complex and potentially lethal DNA damage up to several weeks after exposure. An elevated frequency of keratinocytes with persistent RIFs may thus serve as indicator of previous acute radiation exposure, which may be useful in the follow up of nuclear or radiological accident scenarios.

  14. Estimation of effective dose equivalente from external irradiations

    International Nuclear Information System (INIS)

    Wakabayashi, T.

    1985-07-01

    A methodology for computing effective dose equivalent, derived from the computer code ALGAM: Monte Carlo Estimation of Internal Dose from Gamma-ray Sources in a Phantom Man, developed at Oak Ridge National Laboratory, is presented. The modified code was run for 12 different photon energy levels, from 0,010 Mev to 4.0 Mev, which provides computing the absorved dose, for these energy levels, in each one of the 97 organs of the original code. The code also was run for the principal energy levels used in the calibration of the dosimetric films. The results of the absorved doses per photon obtained for these levels of energy have been transformed in effective dose equivalents. (M.A.C.) [pt

  15. Single point estimation of phenytoin dosing: a reappraisal.

    Science.gov (United States)

    Koup, J R; Gibaldi, M; Godolphin, W

    1981-11-01

    A previously proposed method for estimation of phenytoin dosing requirement using a single serum sample obtained 24 hours after intravenous loading dose (18 mg/Kg) has been re-evaluated. Using more realistic values for the volume of distribution of phenytoin (0.4 to 1.2 L/Kg), simulations indicate that the proposed method will fail to consistently predict dosage requirements. Additional simulations indicate that two samples obtained during the 24 hour interval following the iv loading dose could be used to more reliably predict phenytoin dose requirement. Because of the nonlinear relationship which exists between phenytoin dose administration rate (RO) and the mean steady state serum concentration (CSS), small errors in prediction of the required RO result in much larger errors in CSS.

  16. Maximum likelihood estimation for cytogenetic dose-response curves

    International Nuclear Information System (INIS)

    Frome, E.L.; DuFrain, R.J.

    1986-01-01

    In vitro dose-response curves are used to describe the relation between chromosome aberrations and radiation dose for human lymphocytes. The lymphocytes are exposed to low-LET radiation, and the resulting dicentric chromosome aberrations follow the Poisson distribution. The expected yield depends on both the magnitude and the temporal distribution of the dose. A general dose-response model that describes this relation has been presented by Kellerer and Rossi (1972, Current Topics on Radiation Research Quarterly 8, 85-158; 1978, Radiation Research 75, 471-488) using the theory of dual radiation action. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting dose-time-response models are intrinsically nonlinear in the parameters. A general-purpose maximum likelihood estimation procedure is described, and estimation for the nonlinear models is illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure

  17. Absorbed dose to the skin in radiological examinations of upper and lower gastrointestinal tract

    International Nuclear Information System (INIS)

    Zonca, G.; Brusa, A.; Somigliana, A.; Pasqualotto, C.; Sichirollo, A.E.; Bellomi, M.; Cozzi, G.; Severini, A.

    1995-01-01

    Absorbed doses to the skin in radiological examinations of the upper and lower gastronintestinal tract in conventional and digital radiology are evaluated and compared. Absorbed doses were measured with LiF thermoluminescence dosemeters placed on the lower pelvis, umbilicus and forehead of the patient to evaluate the absorbed dose in and outside the primary beam. On 10 patients a reduction in absorbed dose of about 34% for double contrast barium enema and of 66% for upper gastrointestinal tract examinations was revealed with digital radiography equipment. In our working conditions the lower dose requirement for digital radiography is mainly due to image intensifiers and television chains and also, due to our equipment settings, to the dose reduction with digital spot fluorography compared with conventional spot film radiography. (Author)

  18. Assessment of eye, hand and male gonadal skin dose in radiotherapy

    International Nuclear Information System (INIS)

    Pushap, M.P.S.

    1979-01-01

    An attempt has been made to gauge the dose to (1) the eye, (2) the skin of the hands and (3) the gonads from radiotherapy of other parts of the body. The study has been done on actual male patients at the Jorjani Medical Centre, Tehran. The study, indicated high dose to the eye lid i.e. about 3% of the tumour dose in the case of head irradiation. The eyes and gonads lie at unequal distances from thorax, so are their doses. It is further emphasised that a minimum dose of 400 rad in three weeks to one month has been reported to be cataractogenic in man. A 50% incidence of progressive loss of vision with a dose of 750 rad to 1000 rad in three weeks to three months time has been observed. If appropriate techniques are not employed to shield the eye, even from stray radiation, such limits may easily be reached. (K.B.)

  19. Increased Skin Dose With the Use of a Custom Mattress for Prone Breast Radiotherapy

    International Nuclear Information System (INIS)

    Becker, Stewart J.; Patel, Rakesh R.; Mackie, Thomas R.

    2007-01-01

    The purpose of this study was to measure and compare the loss of buildup to the skin of the breast in the prone position due to 2 different positioning systems during tangential external beam irradiation. Two experiments were performed; one with a standard nylon-covered foam support and another with a novel helium-filled Mylar bag support. The choice of helium-filled Mylar was to reduce the contamination to as low as possible. The experiments were designed to allow a surface dose measurement and a depth dose profile with the pads placed in the path of the beam in front of the detector. All measurements were taken using a Capintec PS-033 thin-window parallel plate ionization chamber. The standard nylon-covered foam pad caused the surface dose to rise as it got closer to the skin. When the pad was directly touching the surface, the surface dose increased by 300% compared to the result when no pad was present. This loss of buildup to the surface was similar to that of a custom bolus material. The opposite effect occurred with the use of the helium-filled Mylar bag, namely the surface dose gradually decreased as the pad got closer to the phantom. When the Mylar pad was directly touching the phantom, the surface dose was decreased by 7% compared to when no pad was present. The use of a foam pad could potentially result in a significant higher dose to the skin, resulting in an enhanced acute skin reaction. Therefore, special care should be taken in this clinical scenario and further investigation of an air- or helium-based mylar support pad should be investigated in the context of definitive breast radiation treatment

  20. Combination of MALDI-MSI and cassette dosing for evaluation of drug distribution in human skin explant

    DEFF Research Database (Denmark)

    Sørensen, Isabella S; Janfelt, Christian; Nielsen, Mette Marie B

    2017-01-01

    Study of skin penetration and distribution of the drug compounds in the skin is a major challenge in the development of topical drug products for treatment of skin diseases. It is crucial to have fast and efficacious screening methods which can provide information concerning the skin penetration ...... that combination of MALDI-MSI and cassette dosing can be used as a medium throughput screening tool at an early stage in the drug discovery/development process. Graphical abstract Investigation of drug distribution in human skin explant by MALDI-MSI after cassette dosing....

  1. Automated dose estimation for lost or damaged dosimeters

    International Nuclear Information System (INIS)

    Thompson, W.L.; Deininger, R.J.

    1988-01-01

    This paper reports that some dosimetry vendors will compute doses for their customers' lost/damaged dosimeters based upon an average of recent dosimeter readings. However, the vendors usually require authorization from the customer for each such occurrence. Therefore, the tedious task of keeping track of the overdue status of each missing dosimeter and constantly notifying the vendor is still present. Also, depending on the monthly variability of a given person's doses, it may be more valid to use the employee's average dose, his/her highest dose over a recent period, an average dose of other employees with similar job duties for that period, or the maximum permissible dose. Thus, the task of estimating doses for lost/damaged dosimeters cannot be delegated to dosimetry vendor. Instead, the radiation safety department must sue the data supplied by the vendor as input for performing estimates. The process is performed automatically at the Medical Center Hospital of Vermont using a personal computer and a relational database

  2. Dose estimation of the THOR BNCT treatment room

    International Nuclear Information System (INIS)

    Hsu, F.Y.; Liu, H.M.; Yu, C.C.; Huang, Y.H.; Tsai, H.N.

    2006-01-01

    BNCT beam of Tsing Hua Open-pool Reactor (THOR) was designed and constructed since 1998. A treatment room for the newly modified THOR BNCT beam was constructed for the next clinical-stage trials in 2004. Dose distribution in a patient (or a phantom) is important as irradiated with the BNCT beam. The dose distributions for different type of radiations such as neutron and photons in the treatment room are strongly becoming the index or reference of success for a BNCT facility. An ART head phantom was placed in front of the THOR BNCT beam port and was irradiated. In each section of the head phantom, numbers of small holes are inside and separated uniformly. Dual detector: TLD-600 and TLD-700 chips were placed inside these holes within the phantom to distinct doses of neutron and photon. Besides, Dual-TLD chips were latticed placed in the horizontal plane of beam central axis, in the treatment room to estimate the spatial dose distribution of neutron and photon. Gold foils were assisted in TLD dose calibrations. Neutron and photon dose distributions in phantom and spatial dose distributions in the THOR BNCT treatment room were both estimated in this work. Testing and improvement in THOR BNCT beam were continuative during these years. Results of this work could be the reference and be helpful for the further clinical trials in nearly future. (author)

  3. Skin dose from radiotherapy X-ray beams: the influence of energy

    International Nuclear Information System (INIS)

    Butson, M.J.; Metcalfe, P.E.; University of Wollongong, Wollongong, NSW; Mathur, J.N.

    1997-01-01

    Skin-sparing properties of megavoltage photon beams are compromised by electron contamination. Higher energy beams do not necessarily produce lower surface and basal cell layer doses due to this electron contamination. For a 5x5 cm field size the surface doses for 6 MVp and 18 M)p X-ray beams are 10% and 7% of their respective maxima. However, at a field size of 40 x 40cm the percentage surface dose is 42% for both 6 MVp and 18 MVp beams. The introduction of beam modifying devices such as block trays can further reduce the skin-sparing advantages of high energy photon beams. Using a 10 mm perspex block tray, the surface doses for 6 MVp and 18 MVp beams with a 5 x 5 cm field size are 10% and 8%, respectively. At 40 x 40cm, surface doses are 61% and 63% for 6 MVp and 18 MVp beams, respectively. This trend is followed at the basal cell layer depth. At a depth of 1 mm, 18 MVp beam doses are always at least 5% smaller than 6 MVp doses for the same depth at all field sizes when normalized to their respective Dmax values. Results have shown that higher energy photon beams produce a negligible reduction of the delivered dose to the basal cell layer (0.1 mm). Only a small increase in skin sparing is seen at the dermal layer (1 mm), which can be negated by the increased exit dose from an opposing field. (authors)

  4. Dose estimates in a loss of lead shielding truck accident.

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, Matthew L.; Osborn, Douglas M.; Weiner, Ruth F.; Heames, Terence John (Alion Science & Technology Albuquerque, NM)

    2009-08-01

    The radiological transportation risk & consequence program, RADTRAN, has recently added an updated loss of lead shielding (LOS) model to it most recent version, RADTRAN 6.0. The LOS model was used to determine dose estimates to first-responders during a spent nuclear fuel transportation accident. Results varied according to the following: type of accident scenario, percent of lead slump, distance to shipment, and time spent in the area. This document presents a method of creating dose estimates for first-responders using RADTRAN with potential accident scenarios. This may be of particular interest in the event of high speed accidents or fires involving cask punctures.

  5. Patient-specific dose estimation for pediatric chest CT

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P. [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Global Applied Science Laboratory, GE Healthcare, Waukesha, Wisconsin 53188 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham North Carolina 27710 (United States)

    2008-12-15

    Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ

  6. A comparison of skin and chest wall dose delivered with multicatheter, Contura multilumen balloon, and MammoSite breast brachytherapy.

    Science.gov (United States)

    Cuttino, Laurie W; Todor, Dorin; Rosu, Mihaela; Arthur, Douglas W

    2011-01-01

    Skin and chest wall doses have been correlated with toxicity in patients treated with breast brachytherapy . This investigation compared the ability to control skin and chest wall doses between patients treated with multicatheter (MC), Contura multilumen balloon (CMLB), and MammoSite (MS) brachytherapy. 43 patients treated with the MC technique, 45 patients treated with the CMLB, and 83 patients treated with the MS were reviewed. The maximum doses delivered to the skin and chest wall were calculated for all patients. The mean maximum skin doses for the MC, CMLB, and MS were 2.3 Gy (67% of prescription dose), 2.8 Gy (82% of prescription dose), and 3.2 Gy per fraction (94% of prescription dose), respectively. Although the skin distances were similar (p = 0.23) for the two balloon techniques, the mean skin dose with the CMLB was significantly lower than with the MS (p = 0.05). The mean maximum rib doses for the MC, CMLB, and MS were 2.3 Gy (67% of prescription dose), 2.8 Gy (82% of prescription dose), and 3.6 Gy per fraction (105% of prescription dose), respectively. Again, the mean rib dose with the CMLB was significantly lower than with the MS (p = 0.002). The MC and CMLB techniques are associated with significantly lower mean skin and rib doses than is the MS. Treatment with the MS was associated with significantly more patients receiving doses to the skin or rib in excess of 125% of the prescription. Treatment with the CMLB may prove to yield less normal tissue toxicity than treatment with the MS. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. A Comparison of Skin and Chest Wall Dose Delivered With Multicatheter, Contura Multilumen Balloon, and MammoSite Breast Brachytherapy

    International Nuclear Information System (INIS)

    Cuttino, Laurie W.; Todor, Dorin; Rosu, Mihaela; Arthur, Douglas W.

    2011-01-01

    Purpose: Skin and chest wall doses have been correlated with toxicity in patients treated with breast brachytherapy . This investigation compared the ability to control skin and chest wall doses between patients treated with multicatheter (MC), Contura multilumen balloon (CMLB), and MammoSite (MS) brachytherapy. Methods and Materials: 43 patients treated with the MC technique, 45 patients treated with the CMLB, and 83 patients treated with the MS were reviewed. The maximum doses delivered to the skin and chest wall were calculated for all patients. Results: The mean maximum skin doses for the MC, CMLB, and MS were 2.3 Gy (67% of prescription dose), 2.8 Gy (82% of prescription dose), and 3.2 Gy per fraction (94% of prescription dose), respectively. Although the skin distances were similar (p = 0.23) for the two balloon techniques, the mean skin dose with the CMLB was significantly lower than with the MS (p = 0.05). The mean maximum rib doses for the MC, CMLB, and MS were 2.3 Gy (67% of prescription dose), 2.8 Gy (82% of prescription dose), and 3.6 Gy per fraction (105% of prescription dose), respectively. Again, the mean rib dose with the CMLB was significantly lower than with the MS (p = 0.002). Conclusion: The MC and CMLB techniques are associated with significantly lower mean skin and rib doses than is the MS. Treatment with the MS was associated with significantly more patients receiving doses to the skin or rib in excess of 125% of the prescription. Treatment with the CMLB may prove to yield less normal tissue toxicity than treatment with the MS.

  8. Image-based non-contact monitoring of skin texture changed by piloerection for emotion estimation

    Science.gov (United States)

    Uchida, Mihiro; Akaho, Rina; Ogawa, Keiko; Tsumura, Norimichi

    2018-02-01

    In this paper, we find the effective feature values of skin textures captured by non-contact camera to monitor piloerection on the skin for emotion estimation. Recently, emotion estimation is required for service robots to interact with human more naturally. There are a lot of researches of estimating emotion and additional methods are required to improve emotion estimation because using only a few methods may not give enough information for emotion estimation. In the previous study, it is necessary to fix a device on the subject's arm for detecting piloerection, but the contact monitoring can be stress itself and distract the subject from concentrating in the stimuli and evoking strong emotion. So, we focused on the piloerection as the object obtained with non-contact methods. The piloerection is observed as goose bumps on the skin when the subject is emotionally moved, scared and so on. This phenomenon is caused by contraction of arrector pili muscles with the activation of sympathetic nervous system. This piloerection changes skin texture. Skin texture is important in the cosmetic industry to evaluate skin condition. Therefore, we thought that it will be effective to evaluate the condition of skin texture for emotion estimation. The evaluations were performed by extracting the effective feature values from skin textures captured with a high resolution camera. The effective feature values should have high correlation with the degree of piloerection. In this paper, we found that standard deviation of short-line inclination angles in the texture is well correlated with the degree of piloerection.

  9. A computer-assisted procedure for estimating patient exposure and fetal dose in radiographic examinations

    International Nuclear Information System (INIS)

    Glaze, S.; Schneiders, N.; Bushong, S.C.

    1982-01-01

    A computer program for calculating patient entrance exposure and fetal dose for 11 common radiographic examinations was developed. The output intensity measured at 70 kVp and a 30-inch (76-cm) source-to-skin distance was entered into the program. The change in output intensity with changing kVp was examined for 17 single-phase and 12 three-phase x-ray units. The relationships obtained from a least squares regression analysis of the data, along with the technique factors for each examination, were used to calculate patient exposure. Fetal dose was estimated using published fetal dose in mrad (10 -5 Gy) per 1,000 mR (258 μC/kg) entrance exposure values. The computations are fully automated and individualized to each radiographic unit. The information provides a ready reference in large institutions and is particularly useful at smaller facilities that do not have available physicists who can make the calculations immediately

  10. A computer-assisted procedure for estimating patient exposure and fetal dose in radiographic examinations

    International Nuclear Information System (INIS)

    Glaze, S.; Schneiders, N.; Bushong, S.C.

    1982-01-01

    A computer program for calculating patient entrance exposure and fetal dose for 11 common radiographic examinations was developed. The output intensity measured at 70 kVp and a 30-inch (76-cm) source-to-skin distance was entered into the program. The change in output intensity with changing kVp was examined for 17 single-phase and 12 three-phase x-ray units. The relationships obtained from a least squares regression analysis of the data, along with the technique factors for each examination, were used to calculate patient exposure. Fetal dose was estimated using published fetal dose in mrad (10(-5) Gy) per 1,000 mR (258 microC/kg) entrance exposure values. The computations are fully automated and individualized to each radiographic unit. The information provides a ready reference in large institutions and is particularly useful at smaller facilities that do not have available physicians who can make the calculations immediately

  11. Radiation dose in cardiac SPECT/CT: An estimation of SSDE and effective dose

    International Nuclear Information System (INIS)

    Abdollahi, Hamid; Shiri, Isaac; Salimi, Yazdan; Sarebani, Maghsoud; Mehdinia, Reza; Deevband, Mohammad Reza; Mahdavi, Seied Rabi; Sohrabi, Ahmad; Bitarafan-Rajabi, Ahmad

    2016-01-01

    Aims: The dose levels for Computed Tomography (CT) localization and attenuation correction of Single Photon Emission Computed Tomography (SPECT) are limited and reported as Volume Computed Tomography Dose Index (CTDIvol) and Dose-Length Product (DLP). This work presents CT dose estimation from Cardiac SPECT/CT based on new American Association of Physicists in Medicine (AAPM) Size Specific Dose Estimation (SSDE) parameter, effective dose, organ doses and also emission dose from nuclear issue. Material and methods: Myocardial perfusion SPECT/CT for 509 patients was included in the study. SSDE, effective dose and organ dose were calculated using AAPM guideline and Impact-Dose software. Data were analyzed using R and SPSS statistical software. Spearman-Pearson correlation test and linear regression models were used for finding correlations and relationships among parameters. Results: The mean CTDIvol was 1.34 mGy ± 0.19 and the mean SSDE was 1.7 mGy ± 0.16. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The spearman test showed that correlation between body size and organ doses is significant except thyroid and red bone marrow. CTDIvol was strongly dependent on patient size, but SSDE was not. Emission dose was strongly dependent on patient weight, but its dependency was lower to effective diameter. Conclusion: The dose parameters including CTDIvol, DLP, SSDE, effective dose values reported here are very low and below the reference level. This data suggest that appropriate CT acquisition parameters in SPECT/CT localization and attenuation correction are very beneficial for patients and lowering cancer risks.

  12. Radiation dose in cardiac SPECT/CT: An estimation of SSDE and effective dose

    Energy Technology Data Exchange (ETDEWEB)

    Abdollahi, Hamid, E-mail: Hamid_rbp@yahoo.com [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shiri, Isaac [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Salimi, Yazdan [Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sarebani, Maghsoud; Mehdinia, Reza [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Deevband, Mohammad Reza [Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Mahdavi, Seied Rabi [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Radiation Biology Research Center, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sohrabi, Ahmad [Department of Biostatistics, School of Public Health, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Bitarafan-Rajabi, Ahmad, E-mail: bitarafan@hotmail.com [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Department of Nuclear Medicine, Rajaei Cardiovascular, Medical and Research Center, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2016-12-15

    Aims: The dose levels for Computed Tomography (CT) localization and attenuation correction of Single Photon Emission Computed Tomography (SPECT) are limited and reported as Volume Computed Tomography Dose Index (CTDIvol) and Dose-Length Product (DLP). This work presents CT dose estimation from Cardiac SPECT/CT based on new American Association of Physicists in Medicine (AAPM) Size Specific Dose Estimation (SSDE) parameter, effective dose, organ doses and also emission dose from nuclear issue. Material and methods: Myocardial perfusion SPECT/CT for 509 patients was included in the study. SSDE, effective dose and organ dose were calculated using AAPM guideline and Impact-Dose software. Data were analyzed using R and SPSS statistical software. Spearman-Pearson correlation test and linear regression models were used for finding correlations and relationships among parameters. Results: The mean CTDIvol was 1.34 mGy ± 0.19 and the mean SSDE was 1.7 mGy ± 0.16. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The spearman test showed that correlation between body size and organ doses is significant except thyroid and red bone marrow. CTDIvol was strongly dependent on patient size, but SSDE was not. Emission dose was strongly dependent on patient weight, but its dependency was lower to effective diameter. Conclusion: The dose parameters including CTDIvol, DLP, SSDE, effective dose values reported here are very low and below the reference level. This data suggest that appropriate CT acquisition parameters in SPECT/CT localization and attenuation correction are very beneficial for patients and lowering cancer risks.

  13. We can do better than effective dose for estimating or comparing low-dose radiation risks

    International Nuclear Information System (INIS)

    Brenner, D.J.

    2012-01-01

    The effective dose concept was designed to compare the generic risks of exposure to different radiation fields. More commonly these days, it is used to estimate or compare radiation-induced cancer risks. For various reasons, effective dose represents flawed science: for instance, the tissue-specific weighting factors used to calculate effective dose are a subjective mix of different endpoints; and the marked and differing age and gender dependencies for different health detriment endpoints are not taken into account. This paper suggests that effective dose could be replaced with a new quantity, ‘effective risk’, which, like effective dose, is a weighted sum of equivalent doses to different tissues. Unlike effective dose, where the tissue-dependent weighting factors are a set of generic, subjective committee-defined numbers, the weighting factors for effective risk are simply evaluated tissue-specific lifetime cancer risks per unit equivalent dose. Effective risk, which has the potential to be age and gender specific if desired, would perform the same comparative role as effective dose, be just as easy to estimate, be less prone to misuse, be more directly understandable, and would be based on solid science. An added major advantage is that it gives the users some feel for the actual numerical values of the radiation risks they are trying to control.

  14. Measurement of dose to skin using TLD of several radiodiagnostic studies in San Jose, Costa Rica

    International Nuclear Information System (INIS)

    Mora, P.

    1998-01-01

    It is quantified the radiation doses on skin for several radiodiagnostic studies in patients of the Calderon Guardia Hospital in San Jose, Costa Rica at the period October 1997-September 1998 using thermoluminescent dosemeters TLD 100. The crystals receive the decoction standard procedures and they are arranged at the middle of the irradiation field. For a total of 973 radiodiagnostic studies it was found that the dose on skin in mGy are: 2.09 for thorax AP/AP, 5.33 for thorax LAT, 5.35 for skull AP/PA, 2.98 for skull LAT, 10.74 for abdomen, hips and pelvis, 6.20 for spines AP, 9.35 for spines LAT, 11.48 for lumbar columns AP, 29.99 for lumbar columns LAT and 6.87 for intravenous skin diagrams (first plate ap). It is produced thus the first reference bank for the national hospitals, which is compared with the orientation levels of doses for IAEA. Recommendations to diminish the collective doses through quality control programs are discussed, taking as goal to have got radiographs of excellent diagnostic quality, but with the less possible doses. (Author)

  15. Current estimates of radiation risks and implications for dose limits

    International Nuclear Information System (INIS)

    Clarke, R.H.

    1989-01-01

    The publication of the 1988 report of UNSCEAR represents a major step forward in that there is an international consensus on the estimation of risk from exposure to ionising radiation. The estimates of fatal cancers in the UNSCEAR report are up to 4 times the values in the 1977 review. This paper will describe the reasons for the increase, the remaining uncertainties and the implications for dose limits in occupational and public exposure. (author)

  16. High and Low Doses of Ionizing Radiation Induce Different Secretome Profiles in a Human Skin Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qibin; Matzke, Melissa M.; Schepmoes, Athena A.; Moore, Ronald J.; Webb-Robertson, Bobbie-Jo M.; Hu, Zeping; Monroe, Matthew E.; Qian, Weijun; Smith, Richard D.; Morgan, William F.

    2014-03-18

    It is postulated that secreted soluble factors are important contributors of bystander effect and adaptive responses observed in low dose ionizing radiation. Using multidimensional liquid chromatography-mass spectrometry based proteomics, we quantified the changes of skin tissue secretome – the proteins secreted from a full thickness, reconstituted 3-dimensional skin tissue model 48 hr after exposure to 3, 10 and 200 cGy of X-rays. Overall, 135 proteins showed statistical significant difference between the sham (0 cGy) and any of the irradiated groups (3, 10 or 200 cGy) on the basis of Dunnett adjusted t-test; among these, 97 proteins showed a trend of downregulation and 9 proteins showed a trend of upregulation with increasing radiation dose. In addition, there were 21 and 8 proteins observed to have irregular trends with the 10 cGy irradiated group either having the highest or the lowest level among all three radiated doses. Moreover, two proteins, carboxypeptidase E and ubiquitin carboxyl-terminal hydrolase isozyme L1 were sensitive to ionizing radiation, but relatively independent of radiation dose. Conversely, proteasome activator complex subunit 2 protein appeared to be sensitive to the dose of radiation, as rapid upregulation of this protein was observed when radiation doses were increased from 3, to 10 or 200 cGy. These results suggest that different mechanisms of action exist at the secretome level for low and high doses of ionizing radiation.

  17. Comparative study on skin dose measurement using MOSFET and TLD for pediatric patients with acute lymphatic leukemia.

    Science.gov (United States)

    Al-Mohammed, Huda I; Mahyoub, Fareed H; Moftah, Belal A

    2010-07-01

    The object of this study was to compare the difference of skin dose measured in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using metal oxide semiconductor field-effect transistors (mobile MOSFET dose verification system (TN-RD-70-W) and thermoluminescent dosimeters (TLD-100 chips, Harshaw/ Bicron, OH, USA). Because TLD has been the most-commonly used technique in the skin dose measurement of TBI, the aim of the present study is to prove the benefit of using the mobile MOSFET (metal oxide semiconductor field effect transistor) dosimeter, for entrance dose measurements during the total body irradiation (TBI) over thermoluminescent dosimeters (TLD). The measurements involved 10 pediatric patients ages between 3 and 14 years. Thermoluminescent dosimeters and MOSFET dosimetry were performed at 9 different anatomic sites on each patient. The present results show there is a variation between skin dose measured with MOSFET and TLD in all patients, and for every anatomic site selected, there is no significant difference in the dose delivered using MOSFET as compared to the prescribed dose. However, there is a significant difference for every anatomic site using TLD compared with either the prescribed dose or MOSFET. The results indicate that the dosimeter measurements using the MOSFET gave precise measurements of prescribed dose. However, TLD measurement showed significant increased skin dose of cGy as compared to either prescribed dose or MOSFET group. MOSFET dosimeters provide superior dose accuracy for skin dose measurement in TBI as compared with TLD.

  18. Internal dose estimation by bio-assay techniques

    International Nuclear Information System (INIS)

    Sawant, Pramilla D.

    2016-01-01

    Radiation exposure, both external and internal, can occur to radiation workers during the operation of various nuclear fuel cycle facilities and radiation facilities. The assessment of radiation doses to workers, routinely or potentially exposed to radiation, through intake of radionuclide is an integral part of the radiation protection programme. Internal dose is the radiation exposure that results from the intake of radioactive materials into the body by inhalation, ingestion, absorption through the skin or via wounds. Assessment of radiation doses arising from the intake of radioactive material by the workers is termed as internal exposure assessment. Unlike external exposure, internal exposure cannot be measured directly. Its evaluation is based on the calculation of the intake of radionuclide either from direct measurements (e.g, external monitoring of whole body or of specific organs and tissues) or indirect measurements (e.g. radioactivity in urine, faeces, breath or samples from the working environment) (ICRP Pub. 78, 1997 and NRPB-W60, 2004). Another method of internal dose assessment is based on the measurement of airborne radionuclides in the working areas of the facility and the worker's occupancy in those areas

  19. Radiation dose estimates for carbon-11-labelled PET tracers

    International Nuclear Information System (INIS)

    Aart, Jasper van der; Hallett, William A.; Rabiner, Eugenii A.; Passchier, Jan; Comley, Robert A.

    2012-01-01

    Introduction: Carbon-11-labelled positron emission tomography (PET) tracers commonly used in biomedical research expose subjects to ionising radiation. Dosimetry is the measurement of radiation dose, but also commonly refers to the estimation of health risk associated with ionising radiation. This review describes radiation dosimetry of carbon-11-labelled molecules in the context of current PET research and the most widely used regulatory guidelines. Methods: A MEDLINE literature search returned 42 articles; 32 of these were based on human PET data dealing with radiation dosimetry of carbon-11 molecules. Radiation burden expressed as effective dose and maximum absorbed organ dose was compared between tracers. Results: All but one of the carbon-11-labelled PET tracers have an effective dose under 9 μSv/MBq, with a mean of 5.9 μSv/MBq. Data show that serial PET scans in a single subject are feasible for the majority of radiotracers. Conclusion: Although differing in approach, the two most widely used regulatory frameworks (those in the USA and the EU) do not differ substantially with regard to the maximum allowable injected activity per PET study. The predictive validity of animal dosimetry models is critically discussed in relation to human dosimetry. Finally, empirical PET data are related to human dose estimates based on homogenous distribution, generic models and maximum cumulated activities. Despite the contribution of these models to general risk estimation, human dosimetry studies are recommended where continued use of a new PET tracer is foreseen.

  20. Estimation of dose in irradiated chicken bone by ESR method

    International Nuclear Information System (INIS)

    Tanabe, Hiroko; Hougetu, Daisuke

    1998-01-01

    The author studied the conditions needed to routinely estimate the radiation dose in chicken bone by repeated re-irradiation and measuring ESR signals. Chicken meat containing bone was γ-irradiated at doses of up to 3kGy, accepted as the commercially used dose. The results show that points in sample preparation and ESR measurement are as follows: Both ends of bone are cut off and central part of compact bone is used for experiment. To obtain accurate ESR spectrum, marrow should be scraped out completely. Sample bone fragments of 1-2mm particle size and ca.100mg are recommended to obtain stable and maximum signal. In practice, by re-irradiating up to 5kGy and extrapolating data of the signal intensity to zero using linear regression analysis, radiation dose is estimated. For example, in one experiment, estimated doses of chicken bones initially irradiated at 3.0kGy, 1.0kGy, 0.50kGy and 0.25kGy were 3.4kGy, 1.3kGy, 0.81kGy and 0.57kGy. (author)

  1. Maximum likelihood estimation for cytogenetic dose-response curves

    International Nuclear Information System (INIS)

    Frome, E.L; DuFrain, R.J.

    1983-10-01

    In vitro dose-response curves are used to describe the relation between the yield of dicentric chromosome aberrations and radiation dose for human lymphocytes. The dicentric yields follow the Poisson distribution, and the expected yield depends on both the magnitude and the temporal distribution of the dose for low LET radiation. A general dose-response model that describes this relation has been obtained by Kellerer and Rossi using the theory of dual radiation action. The yield of elementary lesions is kappa[γd + g(t, tau)d 2 ], where t is the time and d is dose. The coefficient of the d 2 term is determined by the recovery function and the temporal mode of irradiation. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting models are intrinsically nonlinear in the parameters. A general purpose maximum likelihood estimation procedure is described and illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure

  2. Maximum likelihood estimation for cytogenetic dose-response curves

    Energy Technology Data Exchange (ETDEWEB)

    Frome, E.L; DuFrain, R.J.

    1983-10-01

    In vitro dose-response curves are used to describe the relation between the yield of dicentric chromosome aberrations and radiation dose for human lymphocytes. The dicentric yields follow the Poisson distribution, and the expected yield depends on both the magnitude and the temporal distribution of the dose for low LET radiation. A general dose-response model that describes this relation has been obtained by Kellerer and Rossi using the theory of dual radiation action. The yield of elementary lesions is kappa(..gamma..d + g(t, tau)d/sup 2/), where t is the time and d is dose. The coefficient of the d/sup 2/ term is determined by the recovery function and the temporal mode of irradiation. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting models are intrinsically nonlinear in the parameters. A general purpose maximum likelihood estimation procedure is described and illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure.

  3. Low-dose total skin electron beam therapy for cutaneous lymphoma : Minimal risk of acute toxicities.

    Science.gov (United States)

    Kroeger, Kai; Elsayad, Khaled; Moustakis, Christos; Haverkamp, Uwe; Eich, Hans Theodor

    2017-12-01

    Low-dose total skin electron beam therapy (TSEBT) is attracting increased interest for the effective palliative treatment of primary cutaneous T‑cell lymphoma (pCTCL). In this study, we compared toxicity profiles following various radiation doses. We reviewed the records of 60 patients who underwent TSEBT for pCTCL between 2000 and 2016 at the University Hospital of Munster. The treatment characteristics of the radiotherapy (RT) regimens and adverse events (AEs) were then analyzed and compared. In total, 67 courses of TSEBT were administered to 60 patients. Of these patients, 34 (51%) received a standard dose with a median surface dose of 30 Gy and 33 patients (49%) received a low dose with the median surface dose of 12 Gy (7 salvage low-dose TSEBT courses were administered to 5 patients). After a median follow-up of 15 months, the overall AE rate was 100%, including 38 patients (57%) with grade 2 and 7 (10%) with grade 3 AEs. Patients treated with low-dose TSEBT had significantly fewer grade 2 AEs than those with conventional dose regimens (33 vs. 79%, P dose regimen compared to those with the conventional dose regimens (6 vs. 15%, P = 0.78). Multiple/salvage low-dose TSEBT courses were not associated with an increased risk of acute AEs. Low-dose TSEBT regimens are associated with significantly fewer grade 2 acute toxicities compared with conventional doses of TSEBT. Repeated/Salvage low-dose TSEBT, however, appears to be tolerable and can even be applied safely in patients with cutaneous relapses.

  4. Successfully Managing Impending Skin Necrosis following Hyaluronic Acid Filler Injection, using High-Dose Pulsed Hyaluronidase

    Directory of Open Access Journals (Sweden)

    Kwok Thye David Loh, MBBS

    2018-02-01

    Full Text Available Summary:. Facial fillers are becoming increasingly popular as aesthetic procedures to temporarily reduce the depth of wrinkles or to contour faces. However, even in the hands of very experienced injectors, there is always a small possibility of vascular complications like intra-arterial injection of filler substance. We present a case report of a patient who developed features of vascular obstruction in right infraorbital artery and tell-tale signs of impending skin necrosis, after hyaluronic acid filler injection by an experienced injector. The diagnosis of a vascular complication was made quickly with the help of clinical features like blanching, livedo reticularis, and poor capillary refill. Patient was treated promptly with “high-dose pulsed hyaluronidase protocol” comprising three 1,000-unit pulses of hyaluronidase, administered hourly. There was no further increase in size of the involved area after the first dose of hyaluronidase. All of the involved area, along with 1 cm overlapping in uninvolved skin area, was injected during each injection pulse, using a combination of cannula and needle. Complete reperfusion and good capillary filling were achieved after completion of 3 pulses, and these were taken as the end-point of high-dose pulsed hyaluronidase treatment. Immediate skin changes after filler injections, as well as after hyaluronidase injections and during the 3-week recovery period, were documented with photographs and clinical notes. Involved skin was found to have been fully recovered from this vascular episode, thus indicating that complete recovery of the ischemic skin changes secondary to possible intra-arterial injection could be achieved using high-dose pulsed hyaluronidase protocol.

  5. Effect of wavelength, epidermal thickness and skin type on the required dose for photodynamic therapy

    CSIR Research Space (South Africa)

    Karsten, AE

    2008-10-01

    Full Text Available Effect of Wavelength, Epidermal Thickness and Skin Type on the Required Dose for Photodynamic Therapy A.E. Karsten1,2 1CSIR National Laser Centre, Biophotonics Group, PO Box 395, Pretoria, 0001, South Africa 2Physics Department, Faculty of Natural... a certain depth in the skin. For most laser treatments and diagnostics apllications, wavelengths ranging between 600 and 1 000 nm are used. 1.1 Photodynamic therapy (PDT) In South Africa, as in many other countries, cancer is a major health...

  6. Evaluation of organ dose and estimation of risk due to the abdominal region radiography in Indian adults

    International Nuclear Information System (INIS)

    Kumaresan, M.; Chaubey, Ajay; Kantharia, Surita; Karira, V.; Kumar, Rajesh; Biju, K.; Rao, B.S.

    2006-01-01

    Organ dose, risk of carcinogenesis and genetic effect due to the abdominal region radiography in Indian adult with the help of Monte-Carlo MCNP code by measuring the entrance skin dose by LiF: Mg, Cu, P TL phosphor and the risk coefficients provided by ICRP 60 were estimated. The entrance skin dose for abdominal region radiography was ranges from 2.75 mSv to 18.88 mSv while average entrance skin dose was 8.3 mSv. The bladder, testes and ovary are the important organ those are getting higher dose. The maximum dose for testes, ovary and bladder is 5.37 mSv, 1.45 mSv and 4.74 mSv respectively. The frequency of occurrence of fatal cancers and serious genetic disorders as a consequence of abdominal region radiography ranges from 0.1 to 38.8 risk/10 6 of fatal cancer. Although the estimated risks are small but cannot be neglected. It is important to avoid unnecessary repetitions and also to carry out proper quality assurance tests on the equipment and in the long run it will help reduce the risks and maximize the benefits of radiodiagnosis. These studies may lead to setting up of national reference levels for the diagnostic procedures India. (author)

  7. GARDEC, Estimation of dose-rates reduction by garden decontamination

    International Nuclear Information System (INIS)

    Togawa, Orihiko

    2006-01-01

    1 - Description of program or function: GARDEC estimates the reduction of dose rates by garden decontamination. It provides the effect of different decontamination Methods, the depth of soil to be considered, dose-rate before and after decontamination and the reduction factor. 2 - Methods: This code takes into account three Methods of decontamination : (i)digging a garden in a special way, (ii) a removal of the upper layer of soil, and (iii) covering with a shielding layer of soil. The dose-rate conversion factor is defined as the external dose-rate, in the air, at a given height above the ground from a unit concentration of a specific radionuclide in each soil layer

  8. Developing milk industry estimates for dose reconstruction projects

    International Nuclear Information System (INIS)

    Beck, D.M.; Darwin, R.F.

    1991-01-01

    One of the most important contributors to radiation doses from hanford during the 1944-1947 period was radioactive iodine. Consumption of milk from cows that ate vegetation contaminated with iodine is likely the dominant pathway of human exposure. To estimate the doses people could have received from this pathway, it is necessary to reconstruct the amount of milk consumed by people living near Hanford, the source of the milk, and the type of feed that the milk cows ate. This task is challenging because the dairy industry has undergone radical changes since the end of World War 2, and records that document the impact of these changes on the study area are scarce. Similar problems are faced by researchers on most dose reconstruction efforts. The purpose of this work is to document and evaluate the methods used on the Hanford Environmental Dose Reconstruction (HEDR) Project to reconstruct the milk industry and to present preliminary results

  9. Estimate of absorbed dose received by individuals irradiated with neutrons

    International Nuclear Information System (INIS)

    Fonseca, E.S. da; Mauricio, C.L.P.

    1995-01-01

    An innovating methodology is proposed to estimate the absorbed dose received by individuals irradiated with neutrons in an accident, even in the case that the victim is not using any kind of neutron dosemeter. The method combines direct measurements of 24 Na and 32 P activated in the human body. The calculation method was developed using data taken from previously published papers and experimental measurements. Other irradiations results in different neutron spectra prove the validity of the methodology here proposed. Using a whole body counter to measure 24 Na activity, it is possible to evaluate neutron absorbed doses in the order of 140 μGy of very soft (thermal) spectra. For fast neutron fields, the lower limit for neutron dose detection increases, but the present method continues to be very useful in accidents, with higher neutron doses. (author). 5 refs., 1 fig., 4 tabs

  10. Estimates of effective dose in adult CT examinations

    International Nuclear Information System (INIS)

    Mohamed, Mustafa Awad Elhaj.

    2015-12-01

    The goal of study was to estimate effective dose (E) in adult CT examinations for Toshiba X64 slice using CT. Exp version 2.5 software in Sudan. Using of CT in medical diagnosis delivers radiation doses to patients that are higher than those from other radiological procedures. lack of optimized protocols could be an additional source of increased dose in developing countries. In order to achieve these objectives, data of CT-scanner has been collected from three hospitals ( ANH, ZSH and MMH). Data collected included equipment information and scan parameters for individual patients, who were used to asses. 300 adult patients underwent head, chest, abdomen-pelvis and peivis CT examinations. The CT1_w , CTD1_vol, DLP, patient effective dos and organ doses were estimated, using CT exposure parameters and CT Exp version 2.5 software. A large variation of mean effective dose and organ doses among hospitals was observed for similar CT examinations. These variations largely originated from different CT scanning protocols used in different hospitals and scan length. The mean effective dose in this study in the Brain, PNS, Chest, pulmonary, Abdomen-pelvis, Pelvis, KUB and CTU were 3.2 mSv, 2.6 mSv, 18.9 mSv 17.6 mSv 27.1 mSv, 11.2 mSv, 9.6 mSv and 23.7 mSv respectively, and organ equivalent, doses presented in this study in this study for the eye lens (for head), lungs and thymus ( for chest) , liver, kidney and small intest ( for abdomen t-pelvis), bladder, uterus and gonads ( for pelvis), were 62.9 mSv, 39.5 mSv, 34.1 mSv, 53.9 mSv, 52.6 mSv, 58.1 mSv, 37 mSv, and 34.6 mSv, respectively. These values were mostly comparable to and slightly higher than the values of effective doses reported from similar studies the United Kingdom, Tanzania, Australia, Canada and Sudan. It was concluded that patient effective dose and organ doses could be substantially minimized through careful selection of scanning parameters based on clinical indications of study, patient size, and body

  11. Preliminary study of using imaging plates to map skin dose of patients in interventional radiology procedures

    International Nuclear Information System (INIS)

    Ohuchi, H.; Satoh, T.; Eguchi, Y.; Mori, K.

    2005-01-01

    A method using europium-doped BaFBr imaging plates (IPs) has been studied for mapping entrance skin doses during interventional radiology (IR); the mapping is useful for detecting overlap between irradiation fields and determining the most exposed skin areas. IPs, which are two-dimensional radiation sensors made of photostimulated luminescence materials, have a linear dose response up to ∼100 Gy, can accurately measure doses from 1 μGy to 10 Gy and can be used repeatedly. Because the energy dependence of IPs is rather high, the IPs were characterised in this study and a sensitivity variation of ∼13% was observed for effective energies of 32.7 to 44.7 keV, which are used in IR procedures. Simulation of actual interventional cardiology procedures showed that the variation of sensitivity was within 5%, meaning that IPs are practical for measuring skin doses during IR. Moreover, the patient data can be stored online and easily called up when IR procedures must be repeated, helping to prevent radiation injuries. (authors)

  12. Split-dose recovery in epithelial and vascular-connective tissue of pig skin

    International Nuclear Information System (INIS)

    Peel, D.M.; Hopewell, J.W.; Simmonds, R.H.; Dodd, P.; Meistrich, M.L.

    1984-01-01

    In the first 16 weeks after irradiation, two distinct waves of reaction can be observed in pig skin; the first wave (3-9 weeks) represents the expression of damage to the epithelium while the second is indicative of primary damage to the dermis, mediated through vascular injury. Following β-irradiation with a strontium-90 applicator, a severe epithelial reaction was seen with little subsequent dermal effects. X-rays (250 kV) on the other hand, produced a minimal epithelial response at doses which led to the development of dermal necrosis after 10-16 weeks. Comparison of single doses with two equal doses separated by 24 h produced a D 2 -D 1 value of 7.0 Gy at the doses which produced moist desquamation in 50% of fields (ED 50 ) after strontium-90 irradiation. After X-irradiation comparison of ED 50 doses for the later dermal reaction suggested a D 2 -D 1 value of 4.5 Gy. Over this same dose range of X-rays the D 2 -D 1 value for the first wave epithelial reaction was 3.5 Gy. These values of D 2 -D 1 for epithelial and dermal reactions in pig skin were compared with published data and were examined in relation to the theoretical predictions of a linear quadratic model for tissue target cell survival. The results were broadly in keeping with the productions of such a model. (Auth.)

  13. Estimation of sound pressure levels of voiced speech from skin vibration of the neck

    NARCIS (Netherlands)

    Svec, JG; Titze, IR; Popolo, PS

    How accurately can sound pressure levels (SPLs) of speech be estimated from skin vibration of the neck? Measurements using a small accelerometer were carried out in 27 subjects (10 males and 17 females) who read Rainbow and Marvin Williams passages in soft, comfortable, and loud voice, while skin

  14. A PC program for estimating organ dose and effective dose values in computed tomography

    International Nuclear Information System (INIS)

    Kalender, W.A.; Schmidt, B.; Schmidt, M.; Zankl, M.

    1999-01-01

    Dose values in CT are specified by the manufacturers for all CT systems and operating conditions in phantoms. It is not trivial, however, to derive dose values in patients from this information. Therefore, we have developed a PC-based program which calculates organ dose and effective dose values for arbitrary scan parameters and anatomical ranges. Values for primary radiation are derived from measurements or manufacturer specifications; values for scattered radiation are derived from Monte Carlo calculations tabulated for standard anthropomorphic phantoms. Based on these values, organ doses can be computed by the program for arbitrary scan protocols in conventional and in spiral CT. Effective dose values are also provided, both with ICRP 26 and ICRP 60 tissue-weighting coefficients. Results for several standard CT protocols are presented in tabular form in this paper. In addition, potential for dose reduction is demonstrated, for example, in spiral CT and in quantitative CT. Providing realistic patient dose estimates for arbitrary CT protocols is relevant both for the physician and the patient, and it is particularly useful for educational and training purposes. The program, called WinDose, is now in use at the Erlangen University hospitals (Germany) as an information tool for radiologists and patients. Further extensions are planned. (orig.)

  15. Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

    International Nuclear Information System (INIS)

    Lucero, J. F.; Rojas, J. I.

    2016-01-01

    Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient’s entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

  16. Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

    Energy Technology Data Exchange (ETDEWEB)

    Lucero, J. F., E-mail: fernando.lucero@hoperadiotherapy.com.gt [Universidad Nacional de Costa Rica, Heredia (Costa Rica); Hope International, Guatemala (Guatemala); Rojas, J. I., E-mail: isaac.rojas@siglo21.cr [Centro Médico Radioterapia Siglo XXI, San José (Costa Rica)

    2016-07-07

    Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient’s entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

  17. Estimating average glandular dose by measuring glandular rate in mammograms

    International Nuclear Information System (INIS)

    Goto, Sachiko; Azuma, Yoshiharu; Sumimoto, Tetsuhiro; Eiho, Shigeru

    2003-01-01

    The glandular rate of the breast was objectively measured in order to calculate individual patient exposure dose (average glandular dose) in mammography. By employing image processing techniques and breast-equivalent phantoms with various glandular rate values, a conversion curve for pixel value to glandular rate can be determined by a neural network. Accordingly, the pixel values in clinical mammograms can be converted to the glandular rate value for each pixel. The individual average glandular dose can therefore be calculated using the individual glandular rates on the basis of the dosimetry method employed for quality control in mammography. In the present study, a data set of 100 craniocaudal mammograms from 50 patients was used to evaluate our method. The average glandular rate and average glandular dose of the data set were 41.2% and 1.79 mGy, respectively. The error in calculating the individual glandular rate can be estimated to be less than ±3%. When the calculation error of the glandular rate is taken into consideration, the error in the individual average glandular dose can be estimated to be 13% or less. We feel that our method for determining the glandular rate from mammograms is useful for minimizing subjectivity in the evaluation of patient breast composition. (author)

  18. Dose-response models for the radiation-induction of skin tumours in mice

    International Nuclear Information System (INIS)

    Papworth, D.G.; Hulse, E.V.

    1983-01-01

    Extensive data on radiation-induced skin tumours in mice were examined using 8 models, all based on the concept that incidences of radiation-induced tumours depend on a combination of two radiation effects: a tumour induction process and the loss of reproductive integrity by the potential tumour cells. Models with and without a threshold were used, in spite of theoretical objections to threshold models. No model fitted well both the epidermal and the dermal tumour data and models which proved to be statistically satisfactory for some of the data were rejected for biological reasons. It is concluded that, for skin tumours, dose-response curves depending on a combination of cancer induction and loss of cellular reproductive integrity are distorted by some special, relatively radio-resistant, factor which we have previously postulated as being involved in radiation skin carcinogenesis. (author)

  19. Time and dose-related changes in the thickness of pig skin after irradiation with single doses of [sup 90]Sr/[sup 90]Y [beta]-rays

    Energy Technology Data Exchange (ETDEWEB)

    Rezvani, M.; Hamlet, R.; Hopewell, J.W.; Sieber, V.K. (Churchill Hospital, Oxford (United Kingdom))

    1994-04-01

    Time-related changes in pig skin thickness have been evaluated using a non-invasive ultrasound technique after exposure to a range of single doses of [sup 90]Sr/[sup 90]Yr [beta]-rays. The reduction in relative skin thickness developed in two distinct phases: the first was between 12 and 20 weeks postirradiation. No further changes were then seen until 52 weeks postirradiation when a second phase of skin thinning was observed. This was complete after 76 weeks and no further changes in relative skin thickness were seen in the maximum follow up period of 129 weeks. The timings of these phases of damage were independent of the radiation dose, however, the severity of both phases of radiation-induced skin thinning were dose related. (Author).

  20. Time and dose-related changes in the thickness of pig skin after irradiation with single doses of 90Sr/90Y β-rays

    International Nuclear Information System (INIS)

    Rezvani, M.; Hamlet, R.; Hopewell, J.W.; Sieber, V.K.

    1994-01-01

    Time-related changes in pig skin thickness have been evaluated using a non-invasive ultrasound technique after exposure to a range of single doses of 90 Sr/ 90 Yr β-rays. The reduction in relative skin thickness developed in two distinct phases: the first was between 12 and 20 weeks postirradiation. No further changes were then seen until 52 weeks postirradiation when a second phase of skin thinning was observed. This was complete after 76 weeks and no further changes in relative skin thickness were seen in the maximum follow up period of 129 weeks. The timings of these phases of damage were independent of the radiation dose, however, the severity of both phases of radiation-induced skin thinning were dose related. (Author)

  1. Estimate of dose in interventional radiology: a study of cases

    International Nuclear Information System (INIS)

    Pinto, N.; Braz, D.; Lopes, R.; Vallim, M.; Padilha, L.; Azevedo, F.; Barroso, R.

    2006-01-01

    Values of absorbed dose taken by patients and professionals involved in interventional radiology can be significant mainly for the reason of these proceedings taking long time of fluoroscopy There are many methods to estimate and reduce doses of radiation in the interventional radiology, particularly because the fluoroscopy is responsible for the high dose contribution in the patient and in the professional. The aim of this work is the thermoluminescent dosimetry to estimate the dose values of the extremities of the professionals involved in the interventional radiology and the product dose-area was investigated using a Diamentor. This evaluation is particularly useful for proceedings that interest multiple parts of the organism. In this study were used thermoluminescent dosimeters (LiF:Mg, Ti - Harshaw) to estimate the dose values of the extremities of the professionals and to calibrate them. They were irradiated with X rays at 50 mGy, in Kerma in air and read in the reader Harshaw-5500. The product dose-area (D.A.P.) were obtained through the Diamentor (M2-P.T.W.) calibrated in Cgy.cm 2 fixed in the exit of the X-rays tube. The patients of these study were divided in three groups: individuals submitted to proceedings of embolization, individuals submitted to cerebral and renal arteriography and individuals submitted to proceedings of Transjungular Inthahepatic Porta Systemic Stent Shunt (TIPS). The texts were always carried out by the same group: radiologist doctor), an auxiliary doctor and a nursing auxiliary. The section of interventional radiology has an Angiostar Plus Siemens equipment type arc C, in which there is trifocal Megalix X-ray tube and a intensifier of image from Sirecon 40-4 HDR/33 HDR. In this work the dose estimated values were 137.25 mSv/year for the doctors, 40.27 mSv/year for the nursing and 51.95 mSv/year for the auxiliary doctor and they are below the rule, but in this study it was not taken in consideration the emergency texts as they were

  2. Estimation of eye lens doses received by pediatric interventional cardiologists.

    Science.gov (United States)

    Alejo, L; Koren, C; Ferrer, C; Corredoira, E; Serrada, A

    2015-09-01

    Maximum Hp(0.07) dose to the eye lens received in a year by the pediatric interventional cardiologists has been estimated. Optically stimulated luminescence dosimeters were placed on the eyes of an anthropomorphic phantom, whose position in the room simulates the most common irradiation conditions. Maximum workload was considered with data collected from procedures performed in the Hospital. None of the maximum values obtained exceed the dose limit of 20 mSv recommended by ICRP. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Estimating effective doses to children from CT examinations

    International Nuclear Information System (INIS)

    Heron, J.C.L.

    2000-01-01

    Full text: Assessing doses to patients in diagnostic radiology is an integral part of implementing optimisation of radiation protection. Sources of normalised data are available for estimating doses to adults undergoing CT examinations, but for children this is not the case. This paper describes a simple method for estimating effective doses arising from paediatric CT examinations. First the effective dose to an adult is calculated, having anatomically matched the scanned regions of the child and the adult and also matched the irradiation conditions. A conversion factor is then applied to the adult effective dose, based on the region of the body being scanned - head, upper or lower trunk. This conversion factor is the child-to-adult ratio of the ratios of effective dose per entrance air kerma (in the absence of the patient) at the FAD. The values of these conversion factors were calculated by deriving effective dose per entrance air kerma at the FAD for new-born, 1, 5, 10, 15 and adult phantoms using four projections (AP, PA, left and right laterals) over a range of beam qualities and FADs.The program PCXMC was used for this purpose. Results to date suggest that the conversion factors to give effective doses for children undergoing CT examinations of the upper trunk are approximately 1.3, 1.2, 1.15, 1.1 and 1.05 for ages 0, 1, 5, 10 and 15 years respectively; CT of the lower trunk - 1.4, 1.3, 1.2, 1.2, 1.1; and CT of the head - 2.3, 2.0, 1.5, 1.3, 1.1. The dependence of these factors on beam quality (HVL from 4 to 10 mm Al) is less than 10%, with harder beams resulting in slightly smaller conversion factors. Dependence on FAD is also less than 10%. Major sources of uncertainties in the conversion factors include matching anatomical regions across the phantoms, and the presence of beam divergence in the z-direction when deriving the factors. The method described provides a simple means of estimating effective doses arising from paediatric CT examinations with

  4. High-resolution gulf water skin temperature estimation using TIR/ASTER

    Digital Repository Service at National Institute of Oceanography (India)

    Kunte, P.D.; ManiMurali, R.; Mahender, K.

    to separate geomorphic features. It is demonstrated that high resolution water skin temperature of small water bodies can be determined correctly, economically and less laboriously using space-based TIR/ASTER and that estimated temperature can be effectively...

  5. Natural radioactivity and estimated dose in Brazilian tobacco products

    International Nuclear Information System (INIS)

    Oliveira, Aline S.G.R. de; Damatto, Sandra R.

    2017-01-01

    Tobacco products contain significant concentrations of natural radionuclides from 238 U and 232 Th series. The consumption of these products increases the internal dose of radiation due to the inhalation of the natural radionuclides. Studies from literature emphasize that tobacco products have measurable concentrations of 210 Po and 210 Pb, and may contribute significantly to the increase of internal radiation dose and a large number of lung cancer in smokers. The objectives of this work were to determine the concentrations (Bq/kg) of the radionuclides 226 Ra, 228 Ra, 210 Pb and 210 Po and calculate the internal doses of radiation due to the consumption of these products. In the present work 71 samples were analyzed, consisting of cigars, unflavored and flavored cigarettes, straw cigarettes, cigars and roll smoke. The samples were purchased in Brazilian popular commercial establishments. The analytical techniques employed were the gross alpha and beta measurement after radiochemical separation for the radionuclides 226 Ra, 228 Ra, 210 Pb and alpha spectrometry for 210 Po. The internal radiation doses were calculated with the activity concentrations determined and using the ICRP Publication 119 dose coefficients. An annual consumption of 3,650 kg of tobacco products was considered. The inhalation rates of each radionuclide followed the rates of the current literature. The estimated mean annual dose varied from 76 to 263μSv/y for the tobacco product studied in this work. (author)

  6. I-125 seed dose estimates in heterogeneous phantom

    International Nuclear Information System (INIS)

    Branco, Isabela S.L.; Antunes, Paula C.G.; Cavalieri, Tassio A.; Moura, Eduardo S.; Zeituni, Carlos A.; Yoriyaz, Helio

    2015-01-01

    Brachytherapy plays an important role in the healing process involving tumors in a variety of diseases. Several studies are currently conducted to examine the heterogeneity effects of different tissues and organs in brachytherapy clinical situations and a great effort has been made to incorporate new methodologies to estimate doses with greater accuracy. The objective of this study is to contribute to the assessment of heterogeneous effects on dose due to I-125 brachytherapy source in the presence of different materials with different densities and chemical compositions. The study was performed in heterogeneous phantoms using materials that simulate human tissues. Among these is quoted: breast, fat, muscle, lungs (exhaled and inhaled) and bones with different densities. Monte Carlo simulations for dose calculation in these phantoms were held and subsequently validated. The model 6711 I-125 seed was considered because it is widely used as a brachytherapy permanent implant and the one used in clinics and hospitals in Brazil. Thermoluminescent dosimeters TLD-700 (LiF: Mg, Ti) were simulated for dose assess. Several tissue configurations and positioning of I-125 sources were studied by simulations for future dose measurements. The methodology of this study so far shall be suitable for accurate dosimetric evaluation for different types of brachytherapy treatments, contributing to brachytherapy planning systems complementation allowing a better assessment of the dose actually delivered to the patient. (author)

  7. Natural radioactivity and estimated dose in Brazilian tobacco products

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Aline S.G.R. de; Damatto, Sandra R., E-mail: aline.oliveira@ipen.br, E-mail: damatto@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    Tobacco products contain significant concentrations of natural radionuclides from {sup 238}U and {sup 232}Th series. The consumption of these products increases the internal dose of radiation due to the inhalation of the natural radionuclides. Studies from literature emphasize that tobacco products have measurable concentrations of {sup 210}Po and {sup 210}Pb, and may contribute significantly to the increase of internal radiation dose and a large number of lung cancer in smokers. The objectives of this work were to determine the concentrations (Bq/kg) of the radionuclides {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 210}Po and calculate the internal doses of radiation due to the consumption of these products. In the present work 71 samples were analyzed, consisting of cigars, unflavored and flavored cigarettes, straw cigarettes, cigars and roll smoke. The samples were purchased in Brazilian popular commercial establishments. The analytical techniques employed were the gross alpha and beta measurement after radiochemical separation for the radionuclides {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and alpha spectrometry for {sup 210}Po. The internal radiation doses were calculated with the activity concentrations determined and using the ICRP Publication 119 dose coefficients. An annual consumption of 3,650 kg of tobacco products was considered. The inhalation rates of each radionuclide followed the rates of the current literature. The estimated mean annual dose varied from 76 to 263μSv/y for the tobacco product studied in this work. (author)

  8. I-125 seed dose estimates in heterogeneous phantom

    Energy Technology Data Exchange (ETDEWEB)

    Branco, Isabela S.L.; Antunes, Paula C.G.; Cavalieri, Tassio A.; Moura, Eduardo S.; Zeituni, Carlos A.; Yoriyaz, Helio, E-mail: isabela.slbranco@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Brachytherapy plays an important role in the healing process involving tumors in a variety of diseases. Several studies are currently conducted to examine the heterogeneity effects of different tissues and organs in brachytherapy clinical situations and a great effort has been made to incorporate new methodologies to estimate doses with greater accuracy. The objective of this study is to contribute to the assessment of heterogeneous effects on dose due to I-125 brachytherapy source in the presence of different materials with different densities and chemical compositions. The study was performed in heterogeneous phantoms using materials that simulate human tissues. Among these is quoted: breast, fat, muscle, lungs (exhaled and inhaled) and bones with different densities. Monte Carlo simulations for dose calculation in these phantoms were held and subsequently validated. The model 6711 I-125 seed was considered because it is widely used as a brachytherapy permanent implant and the one used in clinics and hospitals in Brazil. Thermoluminescent dosimeters TLD-700 (LiF: Mg, Ti) were simulated for dose assess. Several tissue configurations and positioning of I-125 sources were studied by simulations for future dose measurements. The methodology of this study so far shall be suitable for accurate dosimetric evaluation for different types of brachytherapy treatments, contributing to brachytherapy planning systems complementation allowing a better assessment of the dose actually delivered to the patient. (author)

  9. 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.)

  10. Study of dose modification in skin cancers induced by the kind of bolus used - Bibliography

    International Nuclear Information System (INIS)

    Camilleri, Jeremy

    2011-01-01

    As tumour irradiation modalities differ from one pathology to another, and are even proper to each pathology (they depend on tumour nature, histology, size, location, and so on), but as therapeutic objectives remain unchanged (to deliver the prescribed dose to the target-volume with the highest possible precision while preserving as much as possible sane tissues as well as neighbouring organs at risk), this bibliographical study aims, on the one hand, at quantifying the dose variation generated by heterogeneous structures crossed by the electron beam, and on the other hand, at optimising the use of boluses during surface irradiations, notably in the case of skin cancers. The author addresses therapeutic indications of irradiation of skin cancers and of thoracic wall for which the application of a bolus is required, and then the associated irradiation techniques as well as bolus characteristics

  11. Radiologic exposure conditions and resultant skin doses in application of xeroradiography to the orthodontic diagnosis

    International Nuclear Information System (INIS)

    Nakasima, A.; Nakata, S.; Shimizu, K.; Takahama, Y.

    1980-01-01

    Xeroradiography is the recording of radiologic image by a photoelectric process rather than the photochemical one used in conventional radiography. In order to investigate the advantages and disadvantages of xeroradiography in the orthodontic field, minimum xeroradiologic exposure conditions for skull projections, joint projections, and hand projections were established by thirteen examiners and the relationship between the image production and x-ray radiation was compared with conventional film techniques. The advantages of xeroradiograph were finer and clear images caused by the edge effect and wide latitude of xeroradiography; the main hazard was the unavoidable larger skin dose required by the projection procedures. The skin doses with xeroradiography were 2.4 to 16.2 times larger than those with conventional film techniques

  12. Increased dose near the skin due to electromagnetic surface beacon transponder.

    Science.gov (United States)

    Ahn, Kang-Hyun; Manger, Ryan; Halpern, Howard J; Aydogan, Bulent

    2015-05-08

    The purpose of this study was to evaluate the increased dose near the skin from an electromagnetic surface beacon transponder, which is used for localization and tracking organ motion. The bolus effect due to the copper coil surface beacon was evaluated with radiographic film measurements and Monte Carlo simulations. Various beam incidence angles were evaluated for both 6 MV and 18 MV experimentally. We performed simulations using a general-purpose Monte Carlo code MCNPX (Monte Carlo N-Particle) to supplement the experimental data. We modeled the surface beacon geometry using the actual mass of the glass vial and copper coil placed in its L-shaped polyethylene terephthalate tubing casing. Film dosimetry measured factors of 2.2 and 3.0 enhancement in the surface dose for normally incident 6 MV and 18 MV beams, respectively. Although surface dose further increased with incidence angle, the relative contribution from the bolus effect was reduced at the oblique incidence. The enhancement factors were 1.5 and 1.8 for 6 MV and 18 MV, respectively, at an incidence angle of 60°. Monte Carlo simulation confirmed the experimental results and indicated that the epidermal skin dose can reach approximately 50% of the dose at dmax at normal incidence. The overall effect could be acceptable considering the skin dose enhancement is confined to a small area (~ 1 cm2), and can be further reduced by using an opposite beam technique. Further clinical studies are justified in order to study the dosimetric benefit versus possible cosmetic effects of the surface beacon. One such clinical situation would be intact breast radiation therapy, especially large-breasted women.

  13. Main clinical, therapeutic and technical factors related to patient's maximum skin dose in interventional cardiology procedures

    Science.gov (United States)

    Journy, N; Sinno-Tellier, S; Maccia, C; Le Tertre, A; Pirard, P; Pagès, P; Eilstein, D; Donadieu, J; Bar, O

    2012-01-01

    Objective The study aimed to characterise the factors related to the X-ray dose delivered to the patient's skin during interventional cardiology procedures. Methods We studied 177 coronary angiographies (CAs) and/or percutaneous transluminal coronary angioplasties (PTCAs) carried out in a French clinic on the same radiography table. The clinical and therapeutic characteristics, and the technical parameters of the procedures, were collected. The dose area product (DAP) and the maximum skin dose (MSD) were measured by an ionisation chamber (Diamentor; Philips, Amsterdam, The Netherlands) and radiosensitive film (Gafchromic; International Specialty Products Advanced Materials Group, Wayne, NJ). Multivariate analyses were used to assess the effects of the factors of interest on dose. Results The mean MSD and DAP were respectively 389 mGy and 65 Gy cm−2 for CAs, and 916 mGy and 69 Gy cm−2 for PTCAs. For 8% of the procedures, the MSD exceeded 2 Gy. Although a linear relationship between the MSD and the DAP was observed for CAs (r=0.93), a simple extrapolation of such a model to PTCAs would lead to an inadequate assessment of the risk, especially for the highest dose values. For PTCAs, the body mass index, the therapeutic complexity, the fluoroscopy time and the number of cine frames were independent explanatory factors of the MSD, whoever the practitioner was. Moreover, the effect of technical factors such as collimation, cinematography settings and X-ray tube orientations on the DAP was shown. Conclusion Optimising the technical options for interventional procedures and training staff on radiation protection might notably reduce the dose and ultimately avoid patient skin lesions. PMID:22457404

  14. Effect of field size on the reaction of pig skin to single doses of X rays

    Energy Technology Data Exchange (ETDEWEB)

    Hopewell, J W; Young, C M.A. [Churchill Hospital, Oxford (UK)

    1982-05-01

    The importance of the size of the treatment area for the response of the skin to radiation has been studied in the pig. The responses of skin areas of 16 cm/sup 2/ (4 x 4 cm) and 64cm/sup 2/ (16 x 4 cm) were compared after single doses of X rays. In the initial 3-9-week period after irradiation the severity of the erythema reaction, which is associated with epidermal cell death, was not influenced by the area of skin irradiated. For the later dermal response (10-16 weeks) a similar result was obtained. The dose required to produce dermal necrosis in 50% of the fields treated (ED/sub 50/) was approximately 2070 cGy for both field sizes. Additional studies have shown that the ED/sub 50/ for dermal necrosis was not influenced by the age of animals at the time of irradiation. This was despite considerable differences in the vascular density and blood flow in pig skin with increasing age. The apparent contradiction between the results of this experimental study in the pig, which shows no effect of field size, and currently accepted clinical practice is discussed.

  15. Skin Dose Assessment Methodology for Military Personnel at McMurdo Station, Antarctica (1962-1979)

    Science.gov (United States)

    2014-06-01

    Particle size factor (unitless) = Moisture factor (unitless) = Enrichment factor (unitless) Values used for parameters in Equation A-1...forearm (fa) IRF (IRF/IRFfa) See Table A-5 Particle Size Factor (PS) 1.0 Moisture Factor (EM) High humidity, e.g. Pacific Ocean 3.0 Low humidity to... Interception and retention fractions, and effective retention factors ......................... 22 Table B-1. Standard height external skin doses (mSv

  16. Total skin high-dose-rate electron therapy dosimetry using TG-51

    International Nuclear Information System (INIS)

    Gossman, Michael S.; Sharma, Subhash C.

    2004-01-01

    An approach to dosimetry for total skin electron therapy (TSET) is discussed using the currently accepted TG-51 high-energy calibration protocol. The methodology incorporates water phantom data for absolute calibration and plastic phantom data for efficient reference dosimetry. The scheme is simplified to include the high-dose-rate mode conversion and provides support for its use, as it becomes more available on newer linear accelerators. Using a 6-field, modified Stanford technique, one may follow the process for accurate determination of absorbed dose

  17. Estimation of population doses from chest mass screening, 1975

    International Nuclear Information System (INIS)

    Hashizume, Tadashi; Maruyama, Takashi

    1977-01-01

    The population doses in mass photofluorography of the chest were estimated on the basis of nation-wide radiological survey. A total frequency of photofluorographic examinations for the chest mass survey was 18.3 million for males and 15.0 million for females, with a total of 33.3 million. Mass surveys of the chest during the school age are carried out only at the time of admission into the primary school (5 or 6 years old) and at the second class of the junior high school (13 or 14 years old). The gonad doses were determined with an ionization chamber placed at the position of gonad in tissue-equivalent phantoms. The active bone marrow was subdivided into 72 elements. The dose contribution to the marrow arising from the particular exposure conditions was calculated at each site within the elements, using the depth-dose curves experimentally determined and the proportion of the total active bone marrow present at that site. The resultant genetically significant dose for males and females was 0.07 and 0.025 mrad per person per year, respectively, with a total of 0.032 mrad per person per year. The per Caput mean marrow dose for male and female was 5.5 and 4.2 mrad per year, respectively, with a total of 9.7 mrad per year. The leukemia significant dose was calculated from the per Caput mean marrow dose by adopting weighting factor, that is leukemia significant factor. The resultant leukemia significant factor for male and female was 5.2 and 4.1 mrad per person per year, respectively. (auth.)

  18. Composite depth dose measurement for total skin electron (TSE) treatments using radiochromic film

    International Nuclear Information System (INIS)

    Gamble, Lisa M; Farrell, Thomas J; Jones, Glenn W; Hayward, Joseph E

    2003-01-01

    Total skin electron (TSE) radiotherapy is routinely used to treat cutaneous T-cell lymphomas and can be implemented using a modified Stanford technique. In our centre, the composite depth dose for this technique is achieved by a combination of two patient positions per day over a three-day cycle, and two gantry angles per patient position. Due to patient morphology, underdosed regions typically occur and have historically been measured using multiple thermoluminescent dosimeters (TLDs). We show that radiochromic film can be used as a two-dimensional relative dosimeter to measure the percent depth dose in TSE radiotherapy. Composite depth dose curves were measured in a cylindrical, polystyrene phantom and compared with TLD data. Both multiple films (1 film per day) and a single film were used in order to reproduce a realistic clinical scenario. First, three individual films were used to measure the depth dose, one per treatment day, and then compared with TLD data; this comparison showed a reasonable agreement. Secondly, a single film was used to measure the dose delivered over three daily treatments and then compared with TLD data; this comparison showed good agreement throughout the depth dose, which includes doses well below 1 Gy. It will be shown that one piece of radiochromic film is sufficient to measure the composite percent depth dose for a TSE beam, hence making radiochromic film a suitable candidate for monitoring underdosed patient regions

  19. Comparison of skin doses to large fields using tangential beams from cobalt-60 gamma rays and 4-MV x rays

    International Nuclear Information System (INIS)

    Gagnon, W.F.; Peterson, M.D.

    1978-01-01

    Excess radiation to the skin during external beam megavoltage radiation therapy has reportedly caused excessive erythema in patients treated with the Clinac 4 linear accelerator on sloping surfaces, but not for similar treatments with cobalt-60. Doses at the epidermal level were measured under geometries simulating sloping surfaces for a Clinac 4 and an Eldorado 8 cobalt-60 teletherapy machine. For equal doses to the axilla, doses to the epidermal layer were similar. When the tumor dose was calculated for the mediastinum, the dose to the skin in the axillary region was 12% higher for the Clinac 4

  20. The dose penumbra of a custom-made shield used in hemibody skin electron irradiation.

    Science.gov (United States)

    Rivers, Charlotte I; AlDahlawi, Ismail; Wang, Iris Z; Singh, Anurag K; Podgorsak, Matthew B

    2016-11-08

    We report our technique for hemibody skin electron irradiation with a custom-made plywood shield. The technique is similar to our clinical total skin electron irradiation (TSEI), performed with a six-pair dual field (Stanford technique) at an extended source-to-skin distance (SSD) of 377 cm, with the addition of a plywood shield placed at 50 cm from the patient. The shield is made of three layers of stan-dard 5/8'' thick plywood (total thickness of 4.75 cm) that are clamped securely on an adjustable-height stand. Gafchromic EBT3 films were used in assessing the shield's transmission factor and the extent of the dose penumbra region for two different shield-phantom gaps. The shield transmission factor was found to be about 10%. The width of the penumbra (80%-to-20% dose falloff) was measured to be 12 cm for a 50 cm shield-phantom gap, and reduced slightly to 10 cm for a 35 cm shield-phantom gap. In vivo dosimetry of a real case confirmed the expected shielded area dose. © 2016 The Authors.

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

    International Nuclear Information System (INIS)

    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 -1 (1 rad d -1 ). A dose rate no greater than 0.4 mGy h -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 -1 will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be conducted

  2. Assessment of Patients’ Entrance Skin Dose from Diagnostic X-ray Examinations at Public Hospitals of Akwa Ibom State, Nigeria

    Directory of Open Access Journals (Sweden)

    Esen Nsikan U

    2015-07-01

    Full Text Available Introduction High doses of ionizing radiation can lead to adverse health outcomes such as cancer induction in humans. Although the consequences are less evident at very low radiation doses, the associated risks are of societal importance. This study aimed at assessing entrance skin doses (ESDs in patients undergoing selected diagnostic X-ray examinations at public hospitals of Akwa Ibom State, Nigeria. Materials and Methods In total, six examinations were performed on 720 patients in this study.   CALDose_X5 software program was used in estimating ESDs based on patients’ information and technical exposure parameters. Results The estimated ESDs ranged from 0.59 to 0.61 mGy for PA and RLAT projections of the thorax, respectively. ESDs for the AP and RLAT projections of the cranium were 1.65 and 1.48 mGy, respectively. Also, ESD values for the AP view of the abdomen and pelvis were 1.89 and 1.88 mGy, respectively. The mean effective dose was within the range of 0.021-0.075 mGy for the thorax (mean= 0.037, 0.008-0.045 mGy for the cranium (mean= 0.016, 0.215-0.225 mGy for the abdomen (mean= 0.219 and 0.101-0.119 mGy for the pelvis (mean= 0.112. Conclusion The obtained results were comparable to the international reference dose levels, except for the PA projection of the thorax. Therefore, quality assurance programs are required in diagnostic X-ray units of Nigeria hospitals. The obtained findings add to the available data and can help authorities establish reference dose levels for diagnostic radiography in Nigeria.

  3. External dose estimates for future Bikini Atoll inhabitants

    International Nuclear Information System (INIS)

    Gudiksen, P.H.; Crites, T.R.; Robison, W.L.

    1976-01-01

    To evaluate the potential radiation doses that may be received by the returning Bikinians, we surveyed the residual radioactivity on Bikini and Eneu Islands in June of 1975. An integral part of the survey included measurements of gamma-ray exposure rates which are used to estimate external gamma-ray doses. The survey showed that on Bikini Island the rates are highly variable: values near the shores are generally of the order of 10 to 20 μR/h, while those within the interior average about 40 μR/h with a range of roughly 30 to 100 μR/h. Eneu Island, however, is characterized by more or less uniformly distributed gamma radiation levels of less than 10 μR/h over the entire island. These data, in conjunction with population statistics and expected life styles, allowed us to estimate the potential external gamma-ray doses associated with proposed housing locations along the lagoon road and within the interior portions of Bikini Island as well as along the lagoon side of Eneu Island. As expected, living on Eneu Island results in the lowest doses: 0.12 rem during the first year and 2.9 rem during 30 years. The highest values, 0.28 rem during the first year and 5.9 rem over 30 years, may potentially be received by inhabitants living within the interior of Bikini Island. Other options under consideration produce intermediate values

  4. Biological dose estimation in a radiation accident involving low-dose ...

    African Journals Online (AJOL)

    Blood specimens were collected from 8 people 18 days after they had been accidentally exposed to a 947,2 GBq iridium192 source during industrial application. The equivalent whole-body dose received at day 0 was estimated using a model based on quantitative and qualitative chromosome aberration analysis in ...

  5. Estimating adolescent sleep need using dose-response modeling.

    Science.gov (United States)

    Short, Michelle A; Weber, Nathan; Reynolds, Chelsea; Coussens, Scott; Carskadon, Mary A

    2018-04-01

    This study will (1) estimate the nightly sleep need of human adolescents, (2) determine the time course and severity of sleep-related deficits when sleep is reduced below this optimal quantity, and (3) determine whether sleep restriction perturbs the circadian system as well as the sleep homeostat. Thirty-four adolescents aged 15 to 17 years spent 10 days and nine nights in the sleep laboratory. Between two baseline nights and two recovery nights with 10 hours' time in bed (TIB) per night, participants experienced either severe sleep restriction (5-hour TIB), moderate sleep restriction (7.5-hour TIB), or no sleep restriction (10-hour TIB) for five nights. A 10-minute psychomotor vigilance task (PVT; lapse = response after 500 ms) and the Karolinska Sleepiness Scale were administered every 3 hours during wake. Salivary dim-light melatonin onset was calculated at baseline and after four nights of each sleep dose to estimate circadian phase. Dose-dependent deficits to sleep duration, circadian phase timing, lapses of attention, and subjective sleepiness occurred. Less TIB resulted in less sleep, more lapses of attention, greater subjective sleepiness, and larger circadian phase delays. Sleep need estimated from 10-hour TIB sleep opportunities was approximately 9 hours, while modeling PVT lapse data suggested that 9.35 hours of sleep is needed to maintain optimal sustained attention performance. Sleep restriction perturbs homeostatic and circadian systems, leading to dose-dependent deficits to sustained attention and sleepiness. Adolescents require more sleep for optimal functioning than typically obtained.

  6. Functional and morphological changes in pig skin after single or fractionated doses in x rays

    International Nuclear Information System (INIS)

    Young, C.M.A.; Hopewell, J.W.

    1982-01-01

    The flank skin of pigs has been treated with either single or fractionated doses of x-irradiation. A single dose (2070 cGy) was compared with treatment given as 6 fractions in 18 days (6f/18 days; 3780 cGy) or 30 fractions in 39 days (30f/39 days; 8000 cGy). The doses were selected on the basis that similar levels of late tissue damage would result. Radiation induced changes in the skin were assessed by observing the skin reactions and by the measurement of isotope clearance (functional study), relative field contraction, dermal and epidermal thickness and dermal vascular density (morphological studies). In the three treatment groups the early radiation reaction varied considerably. In the first wave reaction (3 to 6 weeks after treatment) bright red erythema was recorded in many fields but moist desquamation developed only in the 30f/39 days treatment group. The second wave (10-16 weeks) was characterized by an ischemic mauve/dusky reaction. Dermal necrosis developed in 50% of the single dose fields. In the 30f/39 days regimen persistent moist desquamation progressed to dermal necrosis. Neither desquamation nor necrosis developed after 6f/18 days. Different levels of vascular damage in the dermis were assessed using an isotope clearance technique; for example in the early reaction significant changes were recorded in the papillary dermis (faster clearance) prior to the development of moist desquamation (30f/39 days) and in the reticular dermis (slower clearance) before necrosis (single dose). Changes in clearance rates have been correlated with changes in the vascular density and thickness of the dermis. Between 26 and 52 weeks (the late reaction) relative field contraction was slightly greater in the 30f/39 days group than in the other treatment groups

  7. A tracking system to calculate patient skin dose in real-time during neurointerventional procedures using a biplane x-ray imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Rana, V. K., E-mail: vkrana@buffalo.edu [Toshiba Stroke and Vascular Research Center, Department of Neurosurgery, State University of New York at Buffalo, Buffalo, New York 14203 (United States); Rudin, S., E-mail: srudin@buffalo.edu; Bednarek, D. R., E-mail: bednarek@buffalo.edu [Toshiba Stroke and Vascular Research Center, Departments of Radiology, Neurosurgery, Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14203 (United States)

    2016-09-15

    in the beam. The calculations are done in real-time with a typical graphic update time of 30 ms and an average vertex separation of 3 mm. With appropriate corrections applied, the Biplane-DTS was able to determine the entrance dose within 6% and the spatial distribution of the dose within 4% compared to the measurements with the ionization chamber and film for the SK150 head phantom. The cumulative dose for overlapping fields from both gantries showed similar agreement. Conclusions: The Biplane-DTS can provide a good estimate of the peak skin dose and cumulative skin dose distribution during biplane neurointerventional procedures. Real-time display of this information should help the physician manage patient dose to reduce the risk of radiation-induced skin injuries.

  8. A tracking system to calculate patient skin dose in real-time during neurointerventional procedures using a biplane x-ray imaging system

    International Nuclear Information System (INIS)

    Rana, V. K.; Rudin, S.; Bednarek, D. R.

    2016-01-01

    in the beam. The calculations are done in real-time with a typical graphic update time of 30 ms and an average vertex separation of 3 mm. With appropriate corrections applied, the Biplane-DTS was able to determine the entrance dose within 6% and the spatial distribution of the dose within 4% compared to the measurements with the ionization chamber and film for the SK150 head phantom. The cumulative dose for overlapping fields from both gantries showed similar agreement. Conclusions: The Biplane-DTS can provide a good estimate of the peak skin dose and cumulative skin dose distribution during biplane neurointerventional procedures. Real-time display of this information should help the physician manage patient dose to reduce the risk of radiation-induced skin injuries.

  9. Problems in radiation absorbed dose estimation from positron emitters

    International Nuclear Information System (INIS)

    Powell, G.F.; Harper, P.V.; Reft, C.S.; Chen, C.T.; Lathrop, K.A.

    1986-01-01

    The positron emitters commonly used in clinical imaging studies for the most part are short-lived, so that when they are distributed in the body the radiation absorbed dose is low even though most of the energy absorbed is from the positrons themselves rather than the annihilation radiation. These considerations do not apply to the administration pathway for a radiopharmaceutical where the activity may be highly concentrated for a brief period rather than distributed in the body. Thus, high local radiation absorbed doses to the vein for an intravenous administration and to the upper airways during administration by inhalation can be expected. For these geometries, beta point source functions (FPS's) have been employed to estimate the radiation absorbed dose in the present study. Physiologic measurements were done to determine other exposure parameters for intravenous administration of O-15 and Rb-82 and for administration of O-15-CO 2 by continuous breathing. Using FPS's to calculate dose rates to the vein wall from O-15 and Rb-82 injected into a vein having an internal radius of 1.5 mm yielded dose rates of 0.51 and 0.46 (rad x g/μCi x h), respectively. The dose gradient in the vein wall and surrounding tissues was also determined using FPS's. Administration of O-15-CO 2 by continuous breathing was also investigated. Using ultra-thin thermoluninescent dosimeters (TLD's) having the effective thickness of normal tracheal mucosa, experiments were performed in which 6 dosimeters were exposed to known concentrations of O-15 positrons in a hemicylindrical tracheal phantom having an internal radius of 0.96 cm and an effective length of 14 cm. The dose rate for these conditions was 3.4 (rads/h)/(μCi/cm 3 ). 15 references, 7 figures, 6 tables

  10. Radiation dose to technologists per nuclear medicine examination and estimation of annual dose.

    Science.gov (United States)

    Bayram, Tuncay; Yilmaz, A Hakan; Demir, Mustafa; Sonmez, Bircan

    2011-03-01

    Conventional diagnostic nuclear medicine applications have been continuously increasing in most nuclear medicine departments in Turkey, but to our knowledge no one has studied the doses to technologists who perform nuclear medicine procedures. Most nuclear medicine laboratories do not have separate control rooms for technologists, who are quite close to the patient during data acquisition. Technologists must therefore stay behind lead shields while performing their task if they are to reduce the radiation dose received. The aim of this study was to determine external radiation doses to technologists during nuclear medicine procedures with and without a lead shield. Another aim was to investigate the occupational annual external radiation doses to Turkish technologists. This study used a Geiger-Müller detector to measure dose rates to technologists at various distances from patients (0.25, 0.50, 1, and 2 m and behind a lead shield) and determined the average time spent by technologists at these distances. Deep-dose equivalents to technologists were obtained. The following conventional nuclear medicine procedures were considered: thyroid scintigraphy performed using (99m)Tc pertechnetate, whole-body bone scanning performed using (99m)Tc-methylene diphosphonate, myocardial perfusion scanning performed using (99m)Tc-methoxyisobutyl isonitrile, and (201)Tl (thallous chloride) and renal scanning performed using (99m)Tc-dimercaptosuccinic acid. The measured deep-dose equivalent to technologists per procedure was within the range of 0.13 ± 0.05 to 0.43 ± 0.17 μSv using a lead shield and 0.21 ± 0.07 to 1.01 ± 0.46 μSv without a lead shield. Also, the annual individual dose to a technologist performing only a particular scintigraphic procedure throughout a year was estimated. For a total of 95 clinical cases (71 patients), effective external radiation doses to technologists were found to be within the permissible levels. This study showed that a 2-mm lead shield

  11. Estimation of effective dose for children in interventional cardiology

    Directory of Open Access Journals (Sweden)

    S. S. Sarycheva

    2017-01-01

    Full Text Available This study is devoted to the estimation of effective dose for children undergoing interventional cardiology examinations. The conversion coefficients (CC from directly measured dose area product (DAP value to effective dose (ED were calculated within the approved effective dose assessment methodology (Guidelines 2.6.1. 2944-11. The CC, Ed K , [mSv / (Gy • cm2] for newborn infants and children of 1, 5, 10 and 15 years old (main(range were calculated as 2.5 (1.8-3.2; 1.1 (0.8-1.3; 0.6 (0.4-0.7; 0.4 (0.3-0.5; and 0,22 (0,18-0,30 respectively. A special Finnish computer program PCXMC 2.0 was used for calculating the dose CC. The series of calculations were made for different values of the physical and geometrical parameters based on their real-existing range of values. The value of CC from DAP to ED were calculated for all pediatric age groups. This work included 153 pediatric interventional studies carried out in two hospitals of the city of St. Petersburg for the period of one year from the summer of 2015. The dose CC dependency from the patient’s age and parameters of the examinations were under the study. The dependence from the beam quality (filtration and tube voltage and age of the patient were found. The younger is the patient, stronger is the filtration and higher is the voltage, the higher is the CC value. The CC in the younger (newborn and older (15 years age groups are different by the factor of 10. It was shown that the changes of the geometric parameters (in the scope of their real existing range have small effect on the value of the effective dose, not exceed 30-50% allowable for radiation protection purpose. The real values of effective doses of children undergoing cardiac interventions were estimated. In severe cases, the values of ED can reach several tens of mSv.

  12. The Effects of Low Dose Irradiation on Inflammatory Response Proteins in a 3D Reconstituted Human Skin Tissue Model

    Energy Technology Data Exchange (ETDEWEB)

    Varnum, Susan M.; Springer, David L.; Chaffee, Mary E.; Lien, Katie A.; Webb-Robertson, Bobbie-Jo M.; Waters, Katrina M.; Sacksteder, Colette A.

    2012-12-01

    Skin responses to moderate and high doses of ionizing radiation include the induction of DNA repair, apoptosis, and stress response pathways. Additionally, numerous studies indicate that radiation exposure leads to inflammatory responses in skin cells and tissue. However, the inflammatory response of skin tissue to low dose radiation (<10 cGy) is poorly understood. In order to address this, we have utilized a reconstituted human skin tissue model (MatTek EpiDerm FT) and assessed changes in 23 cytokines twenty-four and forty eight hours following treatment of skin with either 3 or 10 cGy low-dose of radiation. Three cytokines, IFN-γ, IL-2, MIP-1α, were significantly altered in response to low dose radiation. In contrast, seven cytokines were significantly altered in response to a high radiation dose of 200 cGy (IL-2, IL-10, IL-13, IFN-γ, MIP-1α, TNF α, and VEGF) or the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (G-CSF, GM-CSF, IL-1α, IL-8, MIP-1α, MIP-1β, RANTES). Additionally, radiation induced inflammation appears to have a distinct cytokine response relative to the non-radiation induced stressor, TPA. Overall, these results indicate that there are subtle changes in the inflammatory protein levels following exposure to low dose radiation and this response is a sub-set of what is seen following a high dose in a human skin tissue model.

  13. Estimation of internal dose from radiocesium and phantom

    International Nuclear Information System (INIS)

    Uchiyama, Masafumi; Nakamura, Yuji

    1994-01-01

    A complicated model describing the movement of a radionuclide in both the natural environment and socioeconomical systems is usually used to estimate the internal dose to the public in terms of collective dose, taking demographic data into account. The result can be certified for reliability in some compartments of the model. One of the compartments is the body content. In the case of radiocesium, the individual body burden can be measured using a whole-body counter. The measurement must be calibrated with a phantom. The public is composed of individuals of various ages. Accordingly, the whole-body counter should be calibrated with a set of phantoms approximating individuals of different body sizes. Relationships between counting efficiency and body size were analyzed on 137 Cs 134 Cs or 40 K incorporated into the whole-body using a set of phantoms. Four sizes covering average Japanese physiques from infant to adult male, were chosen to prepare an anthropomorphic phantom system. The distribution of 137 Cs in aquatic solution was homogeneous through the phantom. A whole-body counter at the National Institute of Radiological Sciences, was used at a rate of 5 cm per minute in a scanning mode. The measurements were carried out in an iron room. Relations were analyzed between counting efficiency and some anthropometric parameters. The best fit was given by a linear equation of both reciprocals of height in cm and weight in kg, with a correlation coefficient of 1.00 for 137 Cs. The result indicates that radioactivity of 137 Cs can be determined for individuals with different anthropometric parameters using the whole-body counter system. This means that effective equivalent doses for individuals can be computed accurately from the measurements. Further, an estimate on the body content from an dose estimation model using measurements of radioactivity in environmental substances can be evaluated by comparing the body burden measured. (J.P.N.)

  14. SU-F-T-654: Pacemaker Dose Estimate Using Optically Stimulated Luminescent Dosimeter for Left Breast Intraoperative Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y; Goenka, A; Sharma, A; Wang, L; Cao, Y; Jamshidi, A [Northwell Health, Lake Success, NY (United States)

    2016-06-15

    Purpose: To assess and report the in vivo dose for a patient with a pacemaker being treated in left breast intraoperative radiation therapy (IORT). The ZEISS Intrabeam 50 kVp X-ray beam with a spherical applicator was used. Methods: The optically stimulated luminescent dosimeters (OSLDs) (Landauer nanoDots) were employed and calibrated under the conditions of the Intrabeam 50 kVp X-rays. The nanoDots were placed on the patient at approximately 15 cm away from the lumpectomy cavity both under and above a shield of lead equivalence 0.25 mm (RayShield X-Drape D-110) covering the pacemaker area during IORT with a 5 cm spherical applicator. Results: The skin surface dose near the pacemaker during the IORT with a prescription of 20 Gy was measured as 4.0±0.8 cGy. The dose behind the shield was 0.06±0.01 Gy, demonstrating more than 98% dose reduction. The in vivo skin surface doses during a typical breast IORT at a 4.5 cm spherical applicator surface were further measured at 5, 10, 15, and 20 cm away to be 159±11 cGy, 15±1 cGy, 6.6±0.5 cGy, and 1.8±0.1 cGy, respectively. A power law fit to the dose versus the distance z from the applicator surface yields the dose fall off at the skin surface following z^-2.5, which can be used to estimate skin doses in future cases. The comparison to an extrapolation of depth dose in water reveals an underestimate of far field dose using the manufactory provided data. Conclusion: The study suggests the appropriateness of OSLD as an in vivo skin dosimeter in IORT using the Intrabeam system in a wide dose range. The pacemaker dose measured during the left breast IORT was within a safe limit.

  15. Biological radiation dose estimation by chromosomal aberrations analysis in human peripheral blood (dose- effect curve)

    International Nuclear Information System (INIS)

    Al Achkar, W.

    2002-01-01

    In order to draw a dose-effect curve, blood from eight healthy people were studied. Samples were irradiated in tubes with 0.15-2.5 gray of gamma ray.Irradiated and control samples were incubated for cell cultures. Chromosomal aberrations from 67888 metaphases were scored. Curves from the total number of dicentrics, dicentrics+ rings and total numbers of breaks were drawn. The yield of chromosome aberrations is related to the dose used. These curves give a quick useful estimation of the accidentally radiation exposure. (author)

  16. Estimation of population doses from diagnostic medical examinations in Japan, 1974. II. Estimation of genetically significant dose

    Energy Technology Data Exchange (ETDEWEB)

    Hashizume, T; Maruyama, T; Kumamoto, Y [National Inst. of Radiological Sciences, Chiba (Japan)

    1976-03-01

    The genetically significant dose from radiographic and fluoroscopic examination in Japan has been estimated based on a 1974 nation wide survey of randomly sampled hospitals and clinics. The gonad dose during x-ray diagnosis was determined with an ionization chamber placed at the positions of ovary and testis in a Rando phantom. The instrumented phantom was irradiated with medical diagnostic x-rays on the basis of the exposure data on the patients selected in the nation wide survey. In the calculation of the genetically significant dose, the child expectancy of the patients that undergo each particular type of examination was assumed to be same as that of the general population. The resultant genetically significant dose was 11.1 and 5.43 mrad per person per year for radiography and fluoroscopy, respectively. These values were compared with those of 1960 and 1969. Though the number of examinations per year shows a yearly increase, the genetically significant dose is gradually on the decrease. This may be due to technical improvements in medical radiological practices.

  17. Skin Dose Assessment by Hot Particles in Domestic Nuclear Power Plant

    International Nuclear Information System (INIS)

    Choi, Bo Yeol; Cho, Woon Kap; Lee, Jai Ki

    2009-01-01

    Since a contamination event by hot particles happened due to damaged nuclear fuel at a nuclear power plant (NPP) in the 1980's, skin exposure resulted from hot particles has gotten considerable attention from all the radiation workers in the nuclear industry. In particular, contamination incident caused by hot particles which happened at a NPP in Susquehanna proved that there existed hot particles with the radioactivity of 0.7 GBq, 0.78 GBq, and even 2.78 GBq at maximum. One of these particles was found on a worker's shoe and gave out a dose of 170 mSv. Although there has been no contamination event reported in domestic NPPs which are caused by hot particles, it is hard to conclude that there is no possibility of such contamination for radiation workers. The contaminated samples employed in this study were taken from local NPPs and supposes a case of a worker's skin contaminated by hot particles to evaluate the dose provided to the worker's skin

  18. Dose estimation of interventional cardiologists in different body regions

    International Nuclear Information System (INIS)

    Borba, Iana Q. de; Luz, Renata M. da; Capaverde, Alexandre S.; Silva, Ana M. Marques da; Caramori, Paulo Ricardo Avancini

    2015-01-01

    Interventional radiology is one of the medical specialties that provides the highest doses to professionals, widely used in cardiology, being called interventional cardiology. In order to contribute to the optimization of occupational radiation protection in interventional cardiology procedures, the aim of this study is to evaluate the dose estimation received in different body regions by physicians in interventional cardiology procedures. Two physicians were followed, named as A and B, during one month period, performing a total of 127 procedures (70 for A and 57 for B) of interventional cardiology. During the procedures, dosimeters in different body regions beyond the full-body dosimeter were positioned. The results showed the highest values for the estimated dose received by workers were in the right wrist and left side face regions, for the physician A, and in the left knee and left side face, for the physician B. Results demonstrate the importance of using individual protection equipment by physicians in interventional cardiology, including lead glasses, besides monitoring dosimeters for other body regions, such as wrist, face and knee. (author)

  19. The estimation of occupational effective dose in diagnostic radiology with two dosimeters

    International Nuclear Information System (INIS)

    Niklason, L.T.; Marx, M.V.; Chan, Heang-Ping

    1994-01-01

    Annual effective dose limits have been proposed by national and international radiation protection committees. Radiation protection agencies must decide upon a method of converting the radiation dose measured from dosimeters to an estimate of effective dose. A proposed method for the estimation of effective dose from the radiation dose to two dosimeters is presented. Correction factors are applied to an over-apron collar dose and an under-apron dose to estimate the effective dose. Correction factors are suggested for two cases, both with and without a thyroid shield. Effective dose may be estimated by the under-apron dose plus 6% of the over-collar dose if a thyroid shield is not worn or plus 2% of the over-collar dose if a thyroid shield is worn. This method provides a reasonable estimate of effective dose that is independent of lead apron thickness and accounts for the use of a thyroid shield. 17 refs., 3 tabs

  20. Objective method to report planner-independent skin/rib maximal dose in balloon-based high dose rate (HDR) brachytherapy for breast cancer

    International Nuclear Information System (INIS)

    Kim, Yongbok; Trombetta, Mark G.

    2011-01-01

    Purpose: An objective method was proposed and compared with a manual selection method to determine planner-independent skin and rib maximal dose in balloon-based high dose rate (HDR) brachytherapy planning. Methods: The maximal dose to skin and rib was objectively extracted from a dose volume histogram (DVH) of skin and rib volumes. A virtual skin volume was produced by expanding the skin surface in three dimensions (3D) external to the breast with a certain thickness in the planning computed tomography (CT) images. Therefore, the maximal dose to this volume occurs on the skin surface the same with a conventional manual selection method. The rib was also delineated in the planning CT images and its maximal dose was extracted from its DVH. The absolute (Abdiff=|D max Man -D max DVH |) and relative (Rediff[%]=100x(|D max Man -D max DVH |)/D max DVH ) maximal skin and rib dose differences between the manual selection method (D max Man ) and the objective method (D max DVH ) were measured for 50 balloon-based HDR (25 MammoSite and 25 Contura) patients. Results: The average±standard deviation of maximal dose difference was 1.67%±1.69% of the prescribed dose (PD). No statistical difference was observed between MammoSite and Contura patients for both Abdiff and Rediff[%] values. However, a statistically significant difference (p value max >90%) compared with lower dose range (D max <90%): 2.16%±1.93% vs 1.19%±1.25% with p value of 0.0049. However, the Rediff[%] analysis eliminated the inverse square factor and there was no statistically significant difference (p value=0.8931) between high and low dose ranges. Conclusions: The objective method using volumetric information of skin and rib can determine the planner-independent maximal dose compared with the manual selection method. However, the difference was <2% of PD, on average, if appropriate attention is paid to selecting a manual dose point in 3D planning CT images.

  1. Early estimates of UK radiation doses from the Chernobyl reactor

    International Nuclear Information System (INIS)

    Fry, F.A.; Clarke, R.H.; O'Riordan, M.C.

    1986-01-01

    The plume of radioactive material from the Chernobyl reactor accident passed over the United Kingdom and will increase the radiation dose to the population in the coming year. The increase above the normal annual dose from natural radiation, averaged over persons of all ages, will be about 15% in the north and 1% in the south of the country. Averaged over all ages and areas, the increase will be about 4%. This excess dose will decrease substantially in subsequent years. The accident at the nuclear power station in Chernobyl, near Kiev, on or after 26 April 1986, led to substantial quantities of radioactive material being released to the atmosphere. Wind initially transported the material towards northern and western Europe. Activity was first detected in the southern United Kingdom, some ∼ 2,000 km away, on 2 May. The National Radiological Protection Board (NRPB), the operators of nuclear installations and the regulating authorities, had anticipated this eventuality and had intensified their normal programmes of environmental monitoring. During the following days many measurements were made and a considerable amount of data was generated throughout the country. NRPB was assigned responsibility for collating and evaluating these results; the initial information is used here to make a preliminary estimate of the radiation doses to the population of the United Kingdom

  2. Estimation of the genetically significant dose resulting from diagnostic radiology

    International Nuclear Information System (INIS)

    Angerstein, W.

    1978-01-01

    Based on the average gonad dose received per examination or per film and on the frequency of x-ray examinations (36 million per annum), the mean annual gonad dose to individuals in the GDR has been determined to be 33 mR. Considering different age groups of patients and the fact that the gonad dose to children is often significantly reduced in comparison to adults, estimates of the genetically significant dose (GSD) range from 7 to 19 mR per annum. Examinations of women have accounted for about 66 per cent of the GSD. The highest contribution to the GSD result from examinations of the following organs: kidneys, colon, bile duct (only in women), lumbar spine, pelois, hips, and proximal femur. Despite their high frequency, examinations of the stomach account for only about 3 per cent of the GSD. All thorax examinations (nearly 10,000,000 per annum) contribute less than 0.5 per cent, and the most frequent x-ray examinations of the skeletal system, skull, cervical spine, and teeth account for less than 3 per cent. The GSD values obtained are comparable with those from countries such as India, Japan, Netherlands, USSR, and USA. (author)

  3. 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.

  4. Supplemental computational phantoms to estimate out-of-field absorbed dose in photon radiotherapy

    Science.gov (United States)

    Gallagher, Kyle J.; Tannous, Jaad; Nabha, Racile; Feghali, Joelle Ann; Ayoub, Zeina; Jalbout, Wassim; Youssef, Bassem; Taddei, Phillip J.

    2018-01-01

    The purpose of this study was to develop a straightforward method of supplementing patient anatomy and estimating out-of-field absorbed dose for a cohort of pediatric radiotherapy patients with limited recorded anatomy. A cohort of nine children, aged 2-14 years, who received 3D conformal radiotherapy for low-grade localized brain tumors (LBTs), were randomly selected for this study. The extent of these patients’ computed tomography simulation image sets were cranial only. To approximate their missing anatomy, we supplemented the LBT patients’ image sets with computed tomography images of patients in a previous study with larger extents of matched sex, height, and mass and for whom contours of organs at risk for radiogenic cancer had already been delineated. Rigid fusion was performed between the LBT patients’ data and that of the supplemental computational phantoms using commercial software and in-house codes. In-field dose was calculated with a clinically commissioned treatment planning system, and out-of-field dose was estimated with a previously developed analytical model that was re-fit with parameters based on new measurements for intracranial radiotherapy. Mean doses greater than 1 Gy were found in the red bone marrow, remainder, thyroid, and skin of the patients in this study. Mean organ doses between 150 mGy and 1 Gy were observed in the breast tissue of the girls and lungs of all patients. Distant organs, i.e. prostate, bladder, uterus, and colon, received mean organ doses less than 150 mGy. The mean organ doses of the younger, smaller LBT patients (0-4 years old) were a factor of 2.4 greater than those of the older, larger patients (8-12 years old). Our findings demonstrated the feasibility of a straightforward method of applying supplemental computational phantoms and dose-calculation models to estimate absorbed dose for a set of children of various ages who received radiotherapy and for whom anatomies were largely missing in their original

  5. Influence of TLD position on the estimate of fetal dose

    International Nuclear Information System (INIS)

    Majola, J.; Jamieson, T.J.

    1995-11-01

    This report examines the adequacy of the practice of using a single dosimeter worn at the front of the body as an estimate of the dose received by nuclear medicine technologies. In order to investigate this, a group of approximately 50 technologists at 9 different hospitals were double-badged, i.e. provided with front and back dosimeters, and the ratio of front to back dose computed. Both aggregate data and hospital-specific data are presented and accompanied by several forms of statistical analysis. Apparent trends and possible explanations are discussed. Recommendations are provided for additional studies relating to the badging of nuclear medicine technologists. (author). 125 refs., 15 tabs., 13 figs

  6. Influence of TLD position on the estimate of fetal dose

    Energy Technology Data Exchange (ETDEWEB)

    Majola, J; Jamieson, T J [Science Applications International Corp., Ottawa, ON (Canada)

    1995-11-01

    This report examines the adequacy of the practice of using a single dosimeter worn at the front of the body as an estimate of the dose received by nuclear medicine technologies. In order to investigate this, a group of approximately 50 technologists at 9 different hospitals were double-badged, i.e. provided with front and back dosimeters, and the ratio of front to back dose computed. Both aggregate data and hospital-specific data are presented and accompanied by several forms of statistical analysis. Apparent trends and possible explanations are discussed. Recommendations are provided for additional studies relating to the badging of nuclear medicine technologists. (author). 125 refs., 15 tabs., 13 figs.

  7. Development of dose rate estimation system for FBR maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Iizawa, Katsuyuki [Japan Nuclear Cycle Development Inst., Tsuruga Head Office, International Cooperation and Technology Development Center, Tsuruga, Fukui (Japan); Takeuchi, Jun; Yoshikawa, Satoru [Hitachi Engineering Company, Ltd., Hitachi, Ibaraki (Japan); Urushihara, Hiroshi [Ibaraki Hitachi Information Service Co., Ltd., Omika, Ibaraki (Japan)

    2001-09-01

    During maintenance activities on the primary sodium cooling system by an FBR Personnel radiation exposure arises mainly from the presence of radioactive corrosion products (CP). A CP behavior analysis code, PSYCHE, and a radiation shielding calculation code, QAD-CG, have been developed and applied to investigate the possible reduction of radiation exposure of workers. In order to make these evaluation methods more accessible to plant engineers, the user interface of the codes has been improved and an integrated system, including visualization of the calculated gamma-ray radiation dose-rate map, has been developed. The system has been verified by evaluating the distribution of the radiation dose-rate within the Monju primary heat transport system cells from the estimated saturated CP deposition and distribution which would be present following about 20 cycles of full power operation. (author)

  8. Development of dose rate estimation system for FBR maintenance

    International Nuclear Information System (INIS)

    Iizawa, Katsuyuki; Takeuchi, Jun; Yoshikawa, Satoru; Urushihara, Hiroshi

    2001-01-01

    During maintenance activities on the primary sodium cooling system by an FBR Personnel radiation exposure arises mainly from the presence of radioactive corrosion products (CP). A CP behavior analysis code, PSYCHE, and a radiation shielding calculation code, QAD-CG, have been developed and applied to investigate the possible reduction of radiation exposure of workers. In order to make these evaluation methods more accessible to plant engineers, the user interface of the codes has been improved and an integrated system, including visualization of the calculated gamma-ray radiation dose-rate map, has been developed. The system has been verified by evaluating the distribution of the radiation dose-rate within the Monju primary heat transport system cells from the estimated saturated CP deposition and distribution which would be present following about 20 cycles of full power operation. (author)

  9. Effects of low or high doses of short wavelength ultraviolet light (UVB) on Langerhans cells and skin allograft survival

    International Nuclear Information System (INIS)

    Odling, K.A.; Halliday, G.M.; Muller, H.K.

    1987-01-01

    Donor C57BL mouse shaved dorsal trunk or tail skin was exposed to high (200 mJ/cm 2 ) or low (40 mJ/cm 2 ) doses of short wavelength ultraviolet light (UVB) before grafting on to the thorax of BALB/c mouse recipients of the same sex. Skin grafted 1-14 days following a single high dose of UVB irradiation was ultrastructurally depleted of LC and survived significantly longer than unirradiated skin before being rejected. After a 21-day interval between exposure and grafting when LC were again present in the epidermis there was no significant difference between treated and control graft survival. Exposure to low dose UVB irradiation only significantly increased graft survival for skin transplanted 1-3 days after irradiation; skin grafted 4 days following irradiation survived for a similar period to unirradiated control skin grafts. Electronmicroscopy showed that the low UVB dose did not deplete LC from the epidermis. We conclude that after low dose UVB treatment the class II MHC antigens on the LC Plasma membrane were lost temporarily, thus prolonging graft survival, but when the plasma membrane antigens were re-expressed graft survival returned to normal. In contrast, high-dose UVB irradiation prolonged graft survival by depleting LC from the epidermis, with graft survival only returning to control values as LC repopulated the epidermis

  10. Revision of risk estimates and implications for dose limits

    International Nuclear Information System (INIS)

    Clarke, R.H.

    1989-01-01

    It has been apparent for some time that our estimates of the risks associated with exposure to ionizing radiation must be increased above those values reported by UNSCEAR in 1977 an dused by ICRP to form their present recommendations. NRPB foresaw some of these changes and introduced interim advice within the UK to restrict exposures of wordkers and members of the public to levels below the existing limits. Since that advice was given, UNSCEAR has produced a 1988 report reviewing human data to provide new estimates of risks associated with exposure at high doses and high doserates. These risk figures are up to 4 times higher than when UNSCEAR reported in 1977. In this paper, the reasons for the changes in the estimates of risk will be described and the current NRPB guidelines for risk factors for protection purposes will be presented. The implications of these new risk factors for the setting of dose limits will then be discussed. (Author). 10 refs.; 2 tabs

  11. Low-dose (10-Gy) total skin electron beam therapy for cutaneous T-cell lymphoma

    DEFF Research Database (Denmark)

    Kamstrup, Maria R; Gniadecki, Robert; Iversen, Lars

    2015-01-01

    a total dose of 10 Gy in 10 fractions. Data from 10 of these patients were published previously but were included in the current pooled data analysis. Outcome measures were response rate, duration of response, and toxicity. RESULTS: The overall response rate was 95% with a complete cutaneous response......PURPOSE: Cutaneous T-cell lymphomas (CTCLs) are dominated by mycosis fungoides (MF) and Sézary syndrome (SS), and durable disease control is a therapeutic challenge. Standard total skin electron beam therapy (TSEBT) is an effective skin-directed therapy, but the possibility of retreatments...... or a very good partial response rate (response was 174 days (5.8 months; range: 60-675 days). TSEBT-related acute adverse events (grade 1 or 2) were observed in 60% of patients. CONCLUSIONS...

  12. Dosing of cytotoxic chemotherapy: impact of renal function estimates on dose.

    Science.gov (United States)

    Dooley, M J; Poole, S G; Rischin, D

    2013-11-01

    Oncology clinicians are now routinely provided with an estimated glomerular filtration rate on pathology reports whenever serum creatinine is requested. The utility of using this for the dose determination of renally excreted drugs compared with other existing methods is needed to inform practice. Renal function was determined by [Tc(99m)]DTPA clearance in adult patients presenting for chemotherapy. Renal function was calculated using the 4-variable Modification of Diet in Renal Disease (4v-MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Cockcroft and Gault (CG), Wright and Martin formulae. Doses for renal excreted cytotoxic drugs, including carboplatin, were calculated. The concordance of the renal function estimates according to the CKD classification with measured Tc(99m)DPTA clearance in 455 adults (median age 64.0 years: range 17-87 years) for the 4v-MDRD, CKD-EPI, CG, Martin and Wright formulae was 47.7%, 56.3%, 46.2%, 56.5% and 60.2%, respectively. Concordance for chemotherapy dose for these formulae was 89.0%, 89.5%, 85.1%, 89.9% and 89.9%, respectively. Concordance for carboplatin dose specifically was 66.4%, 71.4%, 64.0%, 73.8% and 73.2%. All bedside formulae provide similar levels of concordance in dosage selection for the renal excreted chemotherapy drugs when compared with the use of a direct measure of renal function.

  13. Estimation of absorbed doses on the basis of cytogenetic methods

    International Nuclear Information System (INIS)

    Shevchenko, V.A.; Rubanovich, A.V.; Snigiryova, G.P.

    1998-01-01

    Long-term studies in the field of radiation cytogenetics have resulted in the discovery of relationship between induction of chromosome aberrations and the type of ionizing radiation, their intensity and dose. This has served as a basis of biological dosimetry as an area of application of the revealed relationship, and has been used in the practice to estimate absorbed doses in people exposed to emergency irradiation. The necessity of using the methods of biological dosimetry became most pressing in connection with the Chernobyl accident in 1986, as well as in connection with other radiation situations that occurred in nuclear industry of the former USSR. The materials presented in our works demonstrate the possibility of applying cytogenetic methods for assessing absorbed doses in populations of different regions exposed to radiation as a result of accidents at nuclear facilities (Chernobyl, the village Muslymovo on the Techa river, the Three Mile Island nuclear power station in the USA where an accident occurred in 1979). Fundamentally, new possibilities for retrospective dose assessment are provided by the FISH-method that permits the assessment of absorbed doses after several decades since the exposure occurred. In addition, the application of this method makes it possible to restore the dynamics of unstable chromosome aberrations (dicentrics and centric rings), which is important for further improvement of the method of biological dosimetry based on the analysis of unstable chromosome aberrations. The purpose of our presentation is a brief description of the cytogenetic methods used in biological dosimetry, consideration of statistical methods of data analysis and a description of concrete examples of their application. (J.P.N.)

  14. Calculation of local skin doses with ICRP adult mesh-type reference computational phantoms

    Science.gov (United States)

    Yeom, Yeon Soo; Han, Haegin; Choi, Chansoo; Nguyen, Thang Tat; Lee, Hanjin; Shin, Bangho; Kim, Chan Hyeong; Han, Min Cheol

    2018-01-01

    Recently, Task Group 103 of the International Commission on Radiological Protection (ICRP) developed new mesh-type reference computational phantoms (MRCPs) for adult males and females in order to address the limitations of the current voxel-type reference phantoms described in ICRP Publication 110 due to their limited voxel resolutions and the nature of the voxel geometry. One of the substantial advantages of the MRCPs over the ICRP-110 reference phantoms is the inclusion of a 50-μm-thick radiosensitive skin basal-cell layer; however, a methodology for calculating the local skin dose (LSD), i.e., the maximum dose to the basal layer averaged over a 1-cm2 area, has yet to be developed. In the present study, a dedicated program for the LSD calculation with the MRCPs was developed based on the mean shift algorithm and the Geant4 Monte Carlo code. The developed program was used to calculate local skin dose coefficients (LSDCs) for electrons and alpha particles, which were then compared with the values given in ICRP Publication 116 that were produced with a simple tissue-equivalent cube model. The results of the present study show that the LSDCs of the MRCPs are generally in good agreement with the ICRP-116 values for alpha particles, but for electrons, significant differences are found at energies higher than 0.15 MeV. The LSDCs of the MRCPs are greater than the ICRP-116 values by as much as 2.7 times at 10 MeV, which is due mainly to the different curvature between realistic MRCPs ( i.e., curved) and the simple cube model ( i.e., flat).

  15. Perspectives on radiation dose estimates for A-bomb survivors

    International Nuclear Information System (INIS)

    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

  16. Perspectives on radiation dose estimates for A-bomb survivors

    International Nuclear Information System (INIS)

    Loewe, W.E.

    1987-01-01

    For 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 modelling and concomitant detail, and by its decentralized direction, both internationally and internally to the U.S. 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

  17. Normal tissue tolerance to external beam radiation therapy: Skin; Dose de tolerance des tissus sains: la peau et les phaneres

    Energy Technology Data Exchange (ETDEWEB)

    Ginot, A.; Doyen, J.; Hannoun-Levi, J.M.; Courdi, A. [Service d' oncologie-radiotherapie, centre Antoine-Lacassagne, 06 - Nice (France)

    2010-07-15

    Acute skin toxicity is frequent during radiation therapy and can lead to temporary arrest of the treatment. Chronic toxicity can occur and conduct to cosmetic problems. Alopecia is the most frequent toxicity concerning hair and is most of the time reversible. Several factors linked to patients influence skin toxicity, such as under-nutrition, old age, obesity, smoking, skin diseases, autoimmune diseases, failure of DNA reparation. Skin, hair and nail toxicities depend also on radiation schedule. Acute toxicity is greater when dose per fraction increases. Chronic and acute toxicities are more often when total dose increases. Under 45 Gy, the risk of severe skin toxicity is low, and begins above 50 Gy. Skin toxicity depends also on the duration of radiotherapy and split course schedules are associated with less toxicities. Irradiation surface seems to influence skin toxicity but interaction is more complex. Reirradiation is often feasible in case of cancer recurrence but with a risk of grade 3-4 toxicity above all in head and neck cancer. The benefit/risk ratio has to be always precisely evaluated. Permanent alopecia is correlated with the follicle dose. Modern techniques of radiation therapy allow to spare skin. (authors)

  18. 324 Building life cycle dose estimates for planned work

    International Nuclear Information System (INIS)

    Landsman, S.D.; Peterson, C.A.; Thornhill, R.E.

    1995-09-01

    This report describes a tool for use by organizational management teams to plan, manage, and oversee personnel exposures within their organizations. The report encompasses personnel radiation exposures received from activities associated with the B-Cell Cleanout Project, Surveillance and Maintenance Project, the Mk-42 Project, and other minor activities. It is designed to provide verifiable Radiological Performance Reports. The primary area workers receive radiation exposure is the Radiochemical Engineering Complex airlock. Entry to the airlock is necessary for maintenance of cranes and other equipment, and to set up the rail system used to move large pieces of equipment and shipping casks into and out of the airlock. Transfers of equipment and materials from the hot cells in the complex to the airlock are required to allow dose profiles of waste containers, shuffling of waste containers to allow grouting activities to go on, and to allow maintenance of in-cell cranes. Both DOE and the Pacific Northwest Laboratory (PNL) are currently investing in state-of-the-art decontamination equipment. Challenging goals for exposure reduction were established for several broad areas of activity. Exposure estimates and goals developed from these scheduled activities will be compared against actual exposures for scheduled and unscheduled activities that contributed to exposures received by personnel throughout the year. Included in this report are life cycle exposure estimates by calendar year for the B-Cell Cleanout project, a three-year estimate of exposures associated with Surveillance and Maintenance, and known activities for Calendar Year (CY) 1995 associated with several smaller projects. These reports are intended to provide a foundation for future dose estimates, by year, requiring updating as exposure conditions change or new avenues of approach to performing work are developed

  19. 324 Building life cycle dose estimates for planned work

    Energy Technology Data Exchange (ETDEWEB)

    Landsman, S.D.; Peterson, C.A.; Thornhill, R.E.

    1995-09-01

    This report describes a tool for use by organizational management teams to plan, manage, and oversee personnel exposures within their organizations. The report encompasses personnel radiation exposures received from activities associated with the B-Cell Cleanout Project, Surveillance and Maintenance Project, the Mk-42 Project, and other minor activities. It is designed to provide verifiable Radiological Performance Reports. The primary area workers receive radiation exposure is the Radiochemical Engineering Complex airlock. Entry to the airlock is necessary for maintenance of cranes and other equipment, and to set up the rail system used to move large pieces of equipment and shipping casks into and out of the airlock. Transfers of equipment and materials from the hot cells in the complex to the airlock are required to allow dose profiles of waste containers, shuffling of waste containers to allow grouting activities to go on, and to allow maintenance of in-cell cranes. Both DOE and the Pacific Northwest Laboratory (PNL) are currently investing in state-of-the-art decontamination equipment. Challenging goals for exposure reduction were established for several broad areas of activity. Exposure estimates and goals developed from these scheduled activities will be compared against actual exposures for scheduled and unscheduled activities that contributed to exposures received by personnel throughout the year. Included in this report are life cycle exposure estimates by calendar year for the B-Cell Cleanout project, a three-year estimate of exposures associated with Surveillance and Maintenance, and known activities for Calendar Year (CY) 1995 associated with several smaller projects. These reports are intended to provide a foundation for future dose estimates, by year, requiring updating as exposure conditions change or new avenues of approach to performing work are developed.

  20. SU-G-201-14: Is Maximum Skin Dose a Reliable Metric for Accelerated Partial Breast Irradiation with Brachytherapy?

    International Nuclear Information System (INIS)

    Park, S; Ragab, O; Patel, S; Demanes, J; Kamrava, M; Kim, Y

    2016-01-01

    Purpose: To evaluate the reliability of the maximum point dose (Dmax) to the skin surface as a dosimetric constraint, we investigated the correlation between Dmax at the skin surface and dose metrics at various definitions of skin thickness. Methods: 42 patients treated with APBI using a Strut Adjusted Volume Implant (SAVI) applicator between 2010 and 2014 were retrospectively reviewed. Target (PTV-EVAL) and organs at risk (OARs: skin, lung, and ribs) were delineated on a CT following NSABP B-39 guidelines. Six skin structures were contoured: a rind 3cm external to the body surface and 1, 2, 3, 4, and 5mm thick rinds deep to the body surface. Inverse planning simulated annealing optimization was used to deliver 32–34Gy in 8-10 fractions to the target while minimizing OAR doses. Dmax, D0.1cc, D1.0cc, and D2.0cc to the various skin structures were calculated. Linear regressions between the metrics were evaluated using the coefficient of determination (R"2). Results: The average±SD PTV-EVAL volume and cavity-to-skin distances were 71.1±28.5cc and 6.9±5.0mm. The target V90 and V95 were 97.3±2.3% and 95.1±3.2%. The Dmax to the skin structures were 78.7±10.2% (skin surface), 82.2±10.7% (skin-1mm), 89.4±12.6% (skin-2mm), 97.9±15.4% (skin-3mm), 114.1±32.5% (skin-4mm), and 157.0±85.3% (skin-5mm). Linear regression analysis showed D1.0cc and D2.0cc to the skin 1mm and Dmax to the skin-4mm and 5mm were poorly correlated with other metrics (R"2=0.413±0.204). Dmax to the skin surface was well correlated (R"2=0.910±0.047) and D1.0cc to the skin-3mm was strongly correlated with all subsurface skin layers (R"2=0.935±0.050). Conclusion: Dmax to the skin surface is a relevant metric for breast skin dose. Contouring discontinuities in the skin with a 1mm subsurface rind and the active dwells in the skin 4 and 5mm introduced significant variations in skin DVH. D0.1cc, D1.0cc, and D2.0cc to a 3mm skin rind are more robust metrics in breast brachytherapy.

  1. Estimation of dose in dental radiology exams in critical regions; Estimativa de dose em exames de radiologia odontologica em regioes criticas

    Energy Technology Data Exchange (ETDEWEB)

    Bonzoumet, S. P.J.; Braz, D. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LIN/COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear. Lab. de Instrumentacao Nuclear; Barroso, R. C. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Fisica; Mauricio, Claudia; Domingues, Claudio [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Padilha, Lucas [Universidade Federal do Rio de Janeiro (HUCFF/UFRJ), RJ (Brazil). Hospital Universitario Clementino Fraga Filho

    2005-07-01

    The objective of this paper is to estimate the values of doses, which are absorbed dose to the lens and thyroid in a dental X-ray. Thermoluminescence dosimeters were used, once they provide a reading of quality and effectiveness. This study was based on dental exams conducted in patients in order to estimate the dose that disperses to the lens of the eye and for the thyroid during an intraoral exam. Data collection took place in two institutions, one governmental, which had the device SELETRONIC 70X and other particular. This study showed that there is a considerable variation between the appliances. Using the appliance DABI 1070, there was a greater absorption of radiation in the right eye (values greater than 5 mGy) and a lower dose in the thyroid, and the Seletronic 70X presented an incidence of higher dose deposited in the skin and in other points there was a balance in the values. In the appliance SELETRONIC 70X, there was again a greater absorption of radiation in the right eye and a lower setting in the thyroid. The excessive dose, besides does not favor at all for the quality of radiograph, represents a risk for the patient who absorbs unnecessary and harmful radiation to the body.

  2. A methodological approach to a realistic evaluation of skin absorbed doses during manipulation of radioactive sources by means of GAMOS Monte Carlo simulations

    Science.gov (United States)

    Italiano, Antonio; Amato, Ernesto; Auditore, Lucrezia; Baldari, Sergio

    2018-05-01

    The accurate evaluation of the radiation burden associated with radiation absorbed doses to the skin of the extremities during the manipulation of radioactive sources is a critical issue in operational radiological protection, deserving the most accurate calculation approaches available. Monte Carlo simulation of the radiation transport and interaction is the gold standard for the calculation of dose distributions in complex geometries and in presence of extended spectra of multi-radiation sources. We propose the use of Monte Carlo simulations in GAMOS, in order to accurately estimate the dose to the extremities during manipulation of radioactive sources. We report the results of these simulations for 90Y, 131I, 18F and 111In nuclides in water solutions enclosed in glass or plastic receptacles, such as vials or syringes. Skin equivalent doses at 70 μm of depth and dose-depth profiles are reported for different configurations, highlighting the importance of adopting a realistic geometrical configuration in order to get accurate dosimetric estimations. Due to the easiness of implementation of GAMOS simulations, case-specific geometries and nuclides can be adopted and results can be obtained in less than about ten minutes of computation time with a common workstation.

  3. Revisiting Low-Dose Total Skin Electron Beam Therapy in Mycosis Fungoides

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Cameron, E-mail: cameronh@stanford.edu [Department of Dermatology, Stanford Cancer Center, Stanford, California (United States); Young, James; Navi, Daniel [Department of Dermatology, Stanford Cancer Center, Stanford, California (United States); Riaz, Nadeem [Department of Radiation Oncology, Stanford Cancer Center, Stanford, California (United States); Lingala, Bharathi; Kim, Youn [Department of Dermatology, Stanford Cancer Center, Stanford, California (United States); Hoppe, Richard [Department of Radiation Oncology, Stanford Cancer Center, Stanford, California (United States)

    2011-11-15

    Purpose: Total skin electron beam therapy (TSEBT) is a highly effective treatment for mycosis fungoides (MF). The standard course consists of 30 to 36 Gy delivered over an 8- to 10-week period. This regimen is time intensive and associated with significant treatment-related toxicities including erythema, desquamation, anhydrosis, alopecia, and xerosis. The aim of this study was to identify a lower dose alternative while retaining a favorable efficacy profile. Methods and Materials: One hundred two MF patients were identified who had been treated with an initial course of low-dose TSEBT (5-<30 Gy) between 1958 and 1995. Patients had a T stage classification of T2 (generalized patch/plaque, n = 51), T3 (tumor, n = 29), and T4 (erythrodermic, n = 22). Those with extracutaneous disease were excluded. Results: Overall response (OR) rates (>50% improvement) were 90% among patients with T2 to T4 disease receiving 5 to <10 Gy (n = 19). In comparison, OR rates between the 10 to <20 Gy and 20 to <30 Gy subgroups were 98% and 97%, respectively. There was no significant difference in median progression free survival (PFS) in T2 and T3 patients when stratified by dose group, and PFS in each was comparable to that of the standard dose. Conclusions: OR rates associated with low-dose TSEBT in the ranges of 10 to <20 Gy and 20 to <30 Gy are comparable to that of the standard dose ({>=} 30 Gy). Efficacy measures including OS, PFS, and RFS are also favorable. Given that the efficacy profile is similar between 10 and <20 Gy and 20 and <30 Gy, the utility of TSEBT within the lower dose range of 10 to <20 Gy merits further investigation, especially in the context of combined modality treatment.

  4. Skin dose for head and neck cancer patients treated with intensity-modulated radiation therapy(IMRT)

    Science.gov (United States)

    Fu, Hsiao-Ju; Li, Chi-Wei; Tsai, Wei-Ta; Chang, Chih-Chia; Tsang, Yuk-Wah

    2017-11-01

    The reliability of thermoluminescent dosimeters (ultrathin TLD) and ISP Gafchromic EBT2 film to measure the surface dose in phantom and the skin dose in head-and-neck patients treated with intensity-modulated radiation therapy technique(IMRT) is the research focus. Seven-field treatment plans with prescribed dose of 180 cGy were performed on Eclipse treatment planning system which utilized pencil beam calculation algorithm(PBC). In calibration tests, the variance coefficient of the ultrathin TLDs were within 3%. The points on the calibration curve of the Gafchromic film was within 1% variation. Five measurements were taken on phantom using ultrathin TLD and EBT2 film respectively. The measured mean surface doses between ultrathin TLD or EBT2 film were within 5% deviation. Skin doses of 6 patients were measured for initial 5 fractions and the mean dose per-fraction was calculated. If the extrapolated doses for 30 fractions were below 4000 cGy, the skin reaction grading observed according to Radiation Therapy Oncology Group (RTOG) was either grade 1 or grade 2. If surface dose exceeded 5000 cGy in 32 fractions, then grade 3 skin reactions were observed.

  5. Skin dose rate conversion factors after contamination with radiopharmaceuticals: influence of contamination area, epidermal thickness and percutaneous absorption

    International Nuclear Information System (INIS)

    Covens, P; Berus, D; Caveliers, V; Struelens, L; Vanhavere, F; Verellen, D

    2013-01-01

    Skin contamination with radiopharmaceuticals can occur during biomedical research and daily nuclear medicine practice as a result of accidental spills, after contact with bodily fluids of patients or by inattentively touching contaminated materials. Skin dose assessment should be carried out by repeated quantification to map the course of the contamination together with the use of appropriate skin dose rate conversion factors. Contamination is generally characterised by local spots on the palmar surface of the hand and complete decontamination is difficult as a result of percutaneous absorption. This specific issue requires special consideration as to the skin dose rate conversion factors as a measure for the absorbed dose rate to the basal layer of the epidermis. In this work we used Monte Carlo simulations to study the influence of the contamination area, the epidermal thickness and the percutaneous absorption on the absorbed skin dose rate conversion factors for a set of 39 medical radionuclides. The results show that the absorbed dose to the basal layer of the epidermis can differ by up to two orders of magnitude from the operational quantity H p (0.07) when using an appropriate epidermal thickness in combination with the effect of percutaneous absorption. (paper)

  6. Can results from animal studies be used to estimate dose or low dose effects in humans

    International Nuclear Information System (INIS)

    Thomas, J.M.; Eberhardt, L.L.

    1981-01-01

    A method has been devised to extrapolate biological equilibrium levels between animal species and subsequently to humans. Our initial premise was based on the observation that radionuclide retention is normally a function of metabolism so that direct or indirect measures could be described by a power law based on body weights of test animal species. However, we found that such interspecies comparisons ought to be based on the coefficient of the power equation rather than on the exponential parameter. The method is illustrated using retention data obtained from five non-ruminant species (including humans) that were fed radionuclides with different properties. It appears that biological equilibrium level for radionuclides in man can be estimated using data from mice, rats, and dogs. The need to extrapolate low-dose effects data obtained from small animals (usually rodents) to humans is not unique to radiation dosimetry or radiation protection problems. Therefore, some quantitative problems connected with estimating low-dose effects from other disciplines have been reviewed, both because of the concern about effects induced by the radionuclide moiety of a radiopharmaceutical and those of the nonradioactive component. The possibility of extrapolating low-dose effects calculated from animal studies to human is discussed

  7. Can results from animal studies be used to estimate dose or low dose effects in humans

    International Nuclear Information System (INIS)

    Thomas, J.M.; Eberhardt, L.L.

    1981-01-01

    We have devised a method to extrapolate biological equilibrium levels between animal species and subsequently to humans. Our initial premise was based on the observation that radionuclide retention is normally a function of metabolism so that direct or indirect measures could be described by a power law based on body weights of test animal species. However, we found that such interspecies comparisons ought to be based on the coefficient of the power equation rather than on the exponential parameter. The method is illustrated using retention data obtained from five non-ruminant species (including humans) that were fed radionuclides with different properties. It appears that biological equilibrium level for radionuclides in man can be estimated using data from mice, rats and dogs. The need to extrapolate low-dose effects data obtained from small animals (usually rodents) to humans is not unique to radiation dosimetry or radiation protection problems. Therefore, researchers have reviewed some quantitative problems connected with estimating low-dose effects from other disciplines, both because of the concern about effects induced by the radionuclide moiety of a radiopharmaceutical and those of the nonradioactive component. The possibility of extrapolating low-dose effects calculated from animal studies to humans is discussed

  8. Biological radiation dose estimation by chromosomal aberrations analysis in human peripheral blood (dose-effect curve)

    International Nuclear Information System (INIS)

    Al-Achkar, W.

    2001-09-01

    In order to draw a dose-effect curve, experimentally gamma ray induced chromosomal aberrations in human peripheral lymphocytes from eight healthy people were studied. Samples from 4 males and 4 females were irradiated in tubes with 0.15, 0.25, 0.5, 1, 1.5, 2, 2.5 gray of gamma ray (Co 60 at dose rate 0.3 Gy/min). Irradiated and control samples were incubated in 37 centigrade for 48 hours cell cultures. Cell cultures then were stopped and metaphases spread, Giemsa stained to score the induced chromosomal aberrations. Chromosomal aberrations from 67888 metaphases were scored. Curves from the total number of dicentrics, dicentrics + rings and total numbers of breaks in cell for each individual or for all people were drawn. An increase of all chromosomal aberrations types with the elevation of the doses was observed. The yield of chromosome aberrations is related to the dose used. These curves give a quick useful estimation of the accidentally radiation exposure. (author)

  9. Radiation doses to patients in computed tomography including a ready reckoner for dose estimation

    International Nuclear Information System (INIS)

    Szendroe, G.; Axelsson, B.; Leitz, W.

    1995-11-01

    The radiation burden from CT-examinations is still growing in most countries and has reached a considerable part of the total from medical diagnostic x-ray procedures. Efforts for avoiding excess radiation doses are therefore especially well motivated within this field. A survey of CT-examination techniques practised in Sweden showed that standard settings for the exposure variables are used for the vast majority of examinations. Virtually no adjustments to the patient's differences in anatomy have been performed - even for infants and children on average the same settings have been used. The adjustment of the exposure variables to the individual anatomy offers a large potential of dose savings. Amongst the imaging parameters, a change of the radiation dose will primarily influence the noise. As a starting point it is assumed that, irrespective of the patient's anatomy, the same level of noise can be accepted for a certain diagnostic task. To a large extent the noise level is determined by the number of photons that are registered in the detector. Hence, for different patient size and anatomy, the exposure should be adjusted so that the same transmitted photon fluence is achieved. An appendix with a ready reckoner for dose estimation for CT-scanners used in Sweden is attached. 7 refs, 5 figs, 8 tabs

  10. Development of internal dose calculation model and the data base updated IDES (Internal Dose Estimation System)

    International Nuclear Information System (INIS)

    Hongo, Shozo; Yamaguchi, Hiroshi; Takeshita, Hiroshi; Iwai, Satoshi.

    1994-01-01

    A computer program named IDES is developed by BASIC language for a personal computer and translated to C language of engineering work station. The IDES carries out internal dose calculations described in ICRP Publication 30 and it installs the program of transformation method which is an empirical method to estimate absorbed fractions of different physiques from ICRP Referenceman. The program consists of three tasks: productions of SAF for Japanese including children, productions of SEE, Specific Effective Energy, and calculation of effective dose equivalents. Each task and corresponding data file appear as a module so as to meet future requirement for revisions of the related data. Usefulness of IDES is discussed by exemplifying the case that 5 age groups of Japanese intake orally Co-60 or Mn-54. (author)

  11. Chernobyl source term, atmospheric dispersion, and dose estimation

    International Nuclear Information System (INIS)

    Gudiksen, P.H.; Harvey, T.F.; Lange, R.

    1988-02-01

    The Chernobyl source term available for long-range transport was estimated by integration of radiological measurements with atmospheric dispersion modeling, and by reactor core radionuclide inventory estimation in conjunction with WASH-1400 release fractions associated with specific chemical groups. These analyses indicated that essentially all of the noble gases, 80% of the radioiodines, 40% of the radiocesium, 10% of the tellurium, and about 1% or less of the more refractory elements were released. Atmospheric dispersion modeling of the radioactive cloud over the Northern Hemisphere revealed that the cloud became segmented during the first day, with the lower section heading toward Scandinavia and the uppper part heading in a southeasterly direction with subsequent transport across Asia to Japan, the North Pacific, and the west coast of North America. The inhalation doses due to direct cloud exposure were estimated to exceed 10 mGy near the Chernobyl area, to range between 0.1 and 0.001 mGy within most of Europe, and to be generally less than 0.00001 mGy within the US. The Chernobyl source term was several orders of magnitude greater than those associated with the Windscale and TMI reactor accidents, while the 137 Cs from the Chernobyl event is about 6% of that released by the US and USSR atmospheric nuclear weapon tests. 9 refs., 3 figs., 6 tabs

  12. An effective dose assessment technique with NORM added consumer products using skin-point source on computational human phantom

    International Nuclear Information System (INIS)

    Yoo, Do Hyeon; Shin, Wook-Geun; Lee, Hyun Cheol; Choi, Hyun Joon; Testa, Mauro; Lee, Jae Kook; Yeom, Yeon Soo; Kim, Chan Hyeong; Min, Chul Hee

    2016-01-01

    The aim of this study is to develop the assessment technique of the effective dose by calculating the organ equivalent dose with a Monte Carlo (MC) simulation and a computational human phantom for the naturally occurring radioactive material (NORM) added consumer products. In this study, we suggests the method determining the MC source term based on the skin-point source enabling the convenient and conservative modeling of the various type of the products. To validate the skin-point source method, the organ equivalent doses were compared with that by the product modeling source of the realistic shape for the pillow, waist supporter, sleeping mattress etc. Our results show that according to the source location, the organ equivalent doses were observed as the similar tendency for both source determining methods, however, it was observed that the annual effective dose with the skin-point source was conservative than that with the modeling source with the maximum 3.3 times higher dose. With the assumption of the gamma energy of 1 MeV and product activity of 1 Bq g"−"1, the annual effective doses of the pillow, waist supporter and sleeping mattress with skin-point source was 3.09E-16 Sv Bq"−"1 year"−"1, 1.45E-15 Sv Bq"−"1 year"−"1, and 2,82E-16 Sv Bq"−"1 year"−"1, respectively, while the product modeling source showed 9.22E-17 Sv Bq"−"1 year"−"1, 9.29E-16 Sv Bq"−"1 year"−"1, and 8.83E-17 Sv Bq"−"1 year"−"1, respectively. In conclusion, it was demonstrated in this study that the skin-point source method could be employed to efficiently evaluate the annual effective dose due to the usage of the NORM added consumer products. - Highlights: • We evaluate the exposure dose from the usage of NORM added consumer products. • We suggest the method determining the MC source term based on the skin-point source. • To validate the skin-point source, the organ equivalent doses were compared with that the modeling source. • The skin-point source could

  13. Estimating the cost of skin cancer detection by dermatology providers in a large health care system.

    Science.gov (United States)

    Matsumoto, Martha; Secrest, Aaron; Anderson, Alyce; Saul, Melissa I; Ho, Jonhan; Kirkwood, John M; Ferris, Laura K

    2018-04-01

    Data on the cost and efficiency of skin cancer detection through total body skin examination are scarce. To determine the number needed to screen (NNS) and biopsy (NNB) and cost per skin cancer diagnosed in a large dermatology practice in patients undergoing total body skin examination. This is a retrospective observational study. During 2011-2015, a total of 20,270 patients underwent 33,647 visits for total body skin examination; 9956 lesion biopsies were performed yielding 2763 skin cancers, including 155 melanomas. The NNS to detect 1 skin cancer was 12.2 (95% confidence interval [CI] 11.7-12.6) and 1 melanoma was 215 (95% CI 185-252). The NNB to detect 1 skin cancer was 3.0 (95% CI 2.9-3.1) and 1 melanoma was 27.8 (95% CI 23.3-33.3). In a multivariable model for NNS, age and personal history of melanoma were significant factors. Age switched from a protective factor to a risk factor at 51 years of age. The estimated cost per melanoma detected was $32,594 (95% CI $27,326-$37,475). Data are from a single health care system and based on physician coding. Melanoma detection through total body skin examination is most efficient in patients ≥50 years of age and those with a personal history of melanoma. Our findings will be helpful in modeling the cost effectiveness of melanoma screening by dermatologists. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  14. Evaluation of radiological protection and dose of skin entrance in paediatric dentistry examinations; Avaliacao da protecao radiologica e da dose de entrada na pele em exames de odontologia pediatrica

    Energy Technology Data Exchange (ETDEWEB)

    Khoury, Helen Jamil [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Vasconcelos, Flavia Maria Nassar de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Silveira, Marcia Maria Fonseca da [Universidade de Pernambuco (UPE), Recife, PE (Brazil). Fac. de Odontologia; Couto, Geraldo Bosco Lindoso [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Fac. de Odontopediatria; Brasileiro, Izabela Vanderley

    2005-07-01

    In this work the radiological protection conditions and dose at the entrance of pediatric patients undergoing dental intraoral radiographs were evaluated. The study was conducted in two clinics of the dentistry course at the Federal University of Pernambuco, Recife, PB, Brazil, equipped with conventional X-ray apparatus, with 60 and 70 kV. 254 exams of 113 patients between the ages of 3 to 12 years were evaluated. The skin entrance dose was estimated using TLD-100 thermoluminescent dosemeters. During the examination were also recorded information regarding the time of exposure, radiographic technique used, use of thyroid protectors and lead apron, angle and distance of the cone Locator to the patient's skin. The results showed that the input skin doses ranged from 0.3 mGy to 10mGy. The lead apron was used in 71% of exams while the thyroid shield was only used in 58% of the exams. The exposure times ranged from 0,5s to 1,5s. From the results it can be concluded that the radiological procedures are not optimized and that in some cases the patient dose is high.

  15. Aspects of pre-dose and other luminescence phenomena in quartz absorbed dose estimation

    International Nuclear Information System (INIS)

    Adamiec, G.

    2000-01-01

    The understanding of all luminescence processes occurring in quartz is of paramount importance in the further development of robust absorbed dose estimation techniques (for the purpose of dating and retrospective dosimetry). The findings presented in this thesis, aid future improvements of absorbed dose estimation techniques using quartz by presenting investigations in the following areas: 1) interpretation of measurement results, 2) numerical modelling of luminescence in quartz, 3) phenomena needing inclusion in future physical models of luminescence. In the first part, the variability of properties of single quartz grains is examined. Through empirical and theoretical considerations, investigations are made of various problems of measurements of luminescence using multi-grain aliquots, and specifically areas where the heterogeneity of the sample at the inter-grain level may be misinterpreted at the multi-grain-aliquot level. The results obtained suggest that the heterogeneity of samples is often overlooked, and that such differences can have a profound influence on the interpretation of measurement results. Discussed are the shape of TL glow curves, OSL decay curves, dose response curves (including consequences for using certain signals as proxies for others), normalisation procedures and D E estimation techniques. Further, a numerical model of luminescence is proposed, which includes multiple R-centres and is used to describe the pre-dose sensitisation in quartz. The numerical model exhibits a broad-scale behaviour observed experimentally in a sample of annealed quartz. The shapes of TAC for lower (20 Gy) and higher doses (1 kGy) and the evolution with temperature of the isothermal sensitisation curves are qualitatively matched for the empirical and numerical systems. In the third area, a preliminary investigation of the properties of the '110 deg. C peak' in the 550 nm emission band, in annealed quartz is presented. These properties are in sharp contrast with

  16. An estimate of cosmic dose component around Kudankulam site

    International Nuclear Information System (INIS)

    Vijayakumar, B.; Thomas, G.; Rajan, P.S.; Selvi, B.S.; Balamurugan, M.; Ravi, P.M.; Tripathi, R.M.

    2015-01-01

    Natural ionizing radiation pervades the whole environment and enters human lives in a wide variety of ways. It arises from natural processes such as the decay of terrestrially deposited radionuclides in the earth, and artificial processes like the use of X-rays in medicine. Thus, radiation can be classified as natural and artificial depending on its origin. Natural sources include cosmic rays, terrestrial gamma radiation, radon and its decay products in air and various radio nuclides found naturally in food and drink. Cosmic rays reach the earth from outer space. Artificial sources include medical X-rays, therapeutic use of radioisotopes, fallout from past weapon tests, discharges from nuclear industry, industrial gamma rays and use of radioisotopes in consumer products. This paper attempts to estimate the natural cosmic dose component around Kudankulam Nuclear Power Plant site in the south eastern coast of India. (author)

  17. Use of doubling doses for the estimation of genetic risks

    International Nuclear Information System (INIS)

    Searle, A.G.

    1977-01-01

    Doubling dose estimates derived from radiation experiments in mice are proving of great value for the assessment of genetic hazards to man from extra radiation exposure because they allow the latest information on mutation frequencies and the incidence of genetic disease in man to be used in the assessment process. The similarity in spectra of 'spontaneous' and induced mutations increases coincidence in the validity of this approach. Data on rates of induction of dominant and recessive mutations, translocations and X-chromosome loss are used to derive doubling doses for chronic exposures to both low and high-LET radiations. Values for γ and X-rays, derived from both male and female germ-cells, fall inside a fairly small range and it is felt that the use of an overall figure of 100 rads is justifiable for protection purposes. Values for neutrons and α-particles, obtained from male germ-cells, varied according to neutron energy etc. but clustered around a value of 5 rads for fission neutrons

  18. Skin dose in longitudinal and transverse linac-MRIs using Monte Carlo and realistic 3D MRI field models.

    Science.gov (United States)

    Keyvanloo, A; Burke, B; Warkentin, B; Tadic, T; Rathee, S; Kirkby, C; Santos, D M; Fallone, B G

    2012-10-01

    The magnetic fields of linac-MR systems modify the path of contaminant electrons in photon beams, which alters patient skin dose. To accurately quantify the magnitude of changes in skin dose, the authors use Monte Carlo calculations that incorporate realistic 3D magnetic field models of longitudinal and transverse linac-MR systems. Finite element method (FEM) is used to generate complete 3D magnetic field maps for 0.56 T longitudinal and transverse linac-MR magnet assemblies, as well as for representative 0.5 and 1.0 T Helmholtz MRI systems. EGSnrc simulations implementing these 3D magnetic fields are performed. The geometry for the BEAMnrc simulations incorporates the Varian 600C 6 MV linac, magnet poles, the yoke, and the magnetic shields of the linac-MRIs. Resulting phase-space files are used to calculate the central axis percent depth-doses in a water phantom and 2D skin dose distributions for 70 μm entrance and exit layers using DOSXYZnrc. For comparison, skin doses are also calculated in the absence of magnetic field, and using a 1D magnetic field with an unrealistically large fringe field. The effects of photon field size, air gap (longitudinal configuration), and angle of obliquity (transverse configuration) are also investigated. Realistic modeling of the 3D magnetic fields shows that fringe fields decay rapidly and have a very small magnitude at the linac head. As a result, longitudinal linac-MR systems mostly confine contaminant electrons that are generated in the air gap and have an insignificant effect on electrons produced further upstream. The increase in the skin dose for the longitudinal configuration compared to the zero B-field case varies from ∼1% to ∼14% for air gaps of 5-31 cm, respectively. (All dose changes are reported as a % of D(max).) The increase is also field-size dependent, ranging from ∼3% at 20 × 20 cm(2) to ∼11% at 5 × 5 cm(2). The small changes in skin dose are in contrast to significant increases that are

  19. Low-dose total skin electron beam therapy for cutaneous lymphoma. Minimal risk of acute toxicities

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, Kai; Elsayad, Khaled; Moustakis, Christos; Haverkamp, Uwe; Eich, Hans Theodor [University Hospital of Muenster, Department of Radiation Oncology, Muenster (Germany)

    2017-12-15

    Low-dose total skin electron beam therapy (TSEBT) is attracting increased interest for the effective palliative treatment of primary cutaneous T-cell lymphoma (pCTCL). In this study, we compared toxicity profiles following various radiation doses. We reviewed the records of 60 patients who underwent TSEBT for pCTCL between 2000 and 2016 at the University Hospital of Munster. The treatment characteristics of the radiotherapy (RT) regimens and adverse events (AEs) were then analyzed and compared. In total, 67 courses of TSEBT were administered to 60 patients. Of these patients, 34 (51%) received a standard dose with a median surface dose of 30 Gy and 33 patients (49%) received a low dose with the median surface dose of 12 Gy (7 salvage low-dose TSEBT courses were administered to 5 patients). After a median follow-up of 15 months, the overall AE rate was 100%, including 38 patients (57%) with grade 2 and 7 (10%) with grade 3 AEs. Patients treated with low-dose TSEBT had significantly fewer grade 2 AEs than those with conventional dose regimens (33 vs. 79%, P < 0.001). A lower grade 3 AE rate was also observed in patients who had received the low-dose regimen compared to those with the conventional dose regimens (6 vs. 15%, P = 0.78). Multiple/salvage low-dose TSEBT courses were not associated with an increased risk of acute AEs. Low-dose TSEBT regimens are associated with significantly fewer grade 2 acute toxicities compared with conventional doses of TSEBT. Repeated/Salvage low-dose TSEBT, however, appears to be tolerable and can even be applied safely in patients with cutaneous relapses. (orig.) [German] Eine niedrigdosierte Ganzhautelektronenbestrahlung (TSEBT) wird vermehrt zur effektiven palliativen Behandlung von Patienten mit primaer kutanen T-Zell-Lymphomen (pCTCL) eingesetzt. In dieser Studie vergleichen wir die Toxizitaetsprofile verschiedener Dosiskonzepte. Untersucht wurden 60 zwischen 2000 und 2016 am Universitaetsklinikum Muenster mittels TSEBT

  20. Immediate hypersensitivity to iodinated contrast media: diagnostic accuracy of skin tests and intravenous provocation test with low dose.

    Science.gov (United States)

    Sesé, L; Gaouar, H; Autegarden, J-E; Alari, A; Amsler, E; Vial-Dupuy, A; Pecquet, C; Francès, C; Soria, A

    2016-03-01

    The diagnosis of HSR to iodinated contrast media (ICM) is challenging based on clinical history and skin tests. This study evaluates the negative predictive value (NPV) of skin tests and intravenous provocation test (IPT) with low-dose ICM in patients with suspected immediate hypersensitivity reaction (HSR) to ICM. Thirty-seven patients with suspected immediate hypersensitivity reaction to ICM were included retrospectively. Skin tests and a single-blind placebo-controlled intravenous provocation test (IPT) with low-dose iodinated contrast media (ICM) were performed. Skin tests with ICM were positive in five cases (one skin prick test and five intradermal test). Thirty-six patients were challenged successfully by IPT, and only one patient had a positive challenge result, with a grade I reaction by the Ring and Messmer classification. Ten of 23 patients followed up by telephone were re-exposed to a negative tested ICM during radiologic examination; two experienced a grade I immediate reaction. For immediate hypersensitivity reaction to ICM, the NPV for skin tests and IPT with low dose was 80% (95% CI 44-97%). © 2016 John Wiley & Sons Ltd.

  1. Response of pig skin to single doses of irradiation from strontium-90 sources of differing surface area

    Energy Technology Data Exchange (ETDEWEB)

    Hopewell, J.W.; Hamlet, R.; Peel, D. (Churchill Hospital, Oxford (UK). Research Inst.)

    1985-08-01

    In the present investigations the effects of irradiation of pig skin with 22.5 and 40 mm diameter /sup 90/Sr plaques are compared. In addition to comparing peak epithelial reactions, comparisons were also made as to the healing times for comparable peak skin reactions for each field size. The ED/sub 50/ values (dose to produce moist desquamation in 50% of the skin fields) 26.5 +- 1.5 Gy for the 22.5 diameter field was not significantly different from that obtained for the larger 40 mm diameter source (ED/sub 50/ 29.0 +- 1.5 Gy).

  2. The response of pig skin to single doses of irradiation from strontium-90 sources of differing surface area

    International Nuclear Information System (INIS)

    Hopewell, J.W.; Hamlet, R.; Peel, D.

    1985-01-01

    In the present investigations the effects of irradiation of pig skin with 22.5 and 40 mm diameter 90 Sr plaques are compared. In addition to comparing peak epithelial reactions, comparisons were also made as to the healing times for comparable peak skin reactions for each field size. The ED 50 values (dose to produce moist desquamation in 50% of the skin fields) 26.5+-1.5 Gy for the 22.5 diameter field was not significantly different from that obtained for the larger 40 mm diameter source (ED 50 29.0+-1.5 Gy). (U.K.)

  3. Influence of the Target Vessel on the Location and Area of Maximum Skin Dose during Percutaneous Coronary Intervention

    International Nuclear Information System (INIS)

    Chida, K.; Fuda, K.; Kagaya, Y.; Saito, H.; Takai, Y.; Kohzuki, M.; Takahash i, S.; Yamada, S.; Zuguchi, M.

    2007-01-01

    Background: A number of cases involving radiation-associated patient skin injury attributable to percutaneous coronary intervention (PCI) have been reported. Knowledge of the location and area of the patient's maximum skin dose (MSD) in PCI is necessary to reduce the risk of skin injury. Purpose: To determine the location and area of the MSD in PCI, and separately analyze the effects of different target vessels. Material and Methods: 197 consecutive PCI procedures were studied, and the location and area of the MSD were calculated by a skin-dose mapping software program: Caregraph. The target vessels of the PCI procedures were divided into four groups based on the American Heart Association (AHA) classification. Results: The sites of the MSD for AHA no.1-3, AHA no.4, and AHA no.11-15 were located mainly on the right back skin, the lower right or center back skin, and the upper back skin areas, respectively, whereas the MSD sites for the AHA no. 5-10 PCI were widely spread. The MSD area for the AHA no. 4 PCI was larger than that for the AHA no. 11-15 PCI (P<0.0001). Conclusion: Although the radiation associated with PCI can be widely spread and variable, we observed a tendency regarding the location and area of the MSD when we separately analyzed the data for different target vessels. We recommend the use of a smaller radiation field size and the elimination of overlapping fields during PCI

  4. Optimizing CT radiation dose based on patient size and image quality: the size-specific dose estimate method

    Energy Technology Data Exchange (ETDEWEB)

    Larson, David B. [Stanford University School of Medicine, Department of Radiology, Stanford, CA (United States)

    2014-10-15

    The principle of ALARA (dose as low as reasonably achievable) calls for dose optimization rather than dose reduction, per se. Optimization of CT radiation dose is accomplished by producing images of acceptable diagnostic image quality using the lowest dose method available. Because it is image quality that constrains the dose, CT dose optimization is primarily a problem of image quality rather than radiation dose. Therefore, the primary focus in CT radiation dose optimization should be on image quality. However, no reliable direct measure of image quality has been developed for routine clinical practice. Until such measures become available, size-specific dose estimates (SSDE) can be used as a reasonable image-quality estimate. The SSDE method of radiation dose optimization for CT abdomen and pelvis consists of plotting SSDE for a sample of examinations as a function of patient size, establishing an SSDE threshold curve based on radiologists' assessment of image quality, and modifying protocols to consistently produce doses that are slightly above the threshold SSDE curve. Challenges in operationalizing CT radiation dose optimization include data gathering and monitoring, managing the complexities of the numerous protocols, scanners and operators, and understanding the relationship of the automated tube current modulation (ATCM) parameters to image quality. Because CT manufacturers currently maintain their ATCM algorithms as secret for proprietary reasons, prospective modeling of SSDE for patient populations is not possible without reverse engineering the ATCM algorithm and, hence, optimization by this method requires a trial-and-error approach. (orig.)

  5. A prospective, open-label study of low-dose total skin electron beam therapy in mycosis fungoides

    DEFF Research Database (Denmark)

    Kamstrup, Maria R; Specht, Lena; Skovgaard, Gunhild L

    2008-01-01

    causes and did not complete treatment. Acute side effects included desquamation, xerosis, and erythema of the skin. No severe side effects were observed. CONCLUSION: Low-dose total skin electron beam therapy can induce complete and partial responses in Stage IB-II mycosis fungoides; however, the duration......PURPOSE: To determine the effect of low-dose (4 Gy) total skin electron beam therapy as a second-line treatment of Stage IB-II mycosis fungoides in a prospective, open-label study. METHODS AND MATERIALS: Ten patients (6 men, 4 women, average age 68.7 years [range, 55-82 years......]) with histopathologically confirmed mycosis fungoides T2-T4 N0-N1 M0 who did not achieve complete remission or relapsed within 4 months after treatment with psoralen plus ultraviolet-A were included. Treatment consisted of low-dose total skin electron beam therapy administered at a total skin dose of 4 Gy given in 4...

  6. Radioactivity levels of basic foodstuffs and dose estimates in Sudan

    International Nuclear Information System (INIS)

    Hemada, H. E. F.

    2009-03-01

    In this work a comprehensive study was carried out for the determination of different radionuclides activities in foodstuff consumed and evaluation of dose levels in different food stuffs were collected from eight States in Sudan (cereals, vegetables, meat, fruits, milk, and fermented milk, baby milk, cans, spices, additives, others). The concentrations of different radionuclides in the food samples were determined by gamma spectrometry using an HPGe detector. Radionuclides observed include: Bi-212, Bi-214, Cs-134, Cs-137, K-40, Pb-212, Pb-214, Ra-224, Ra-226, Th-228, Ac-228, TI-208, Th-232, and U-238. The activity concentration of these radionuclides were found in the following ranges: 0.51 - 19.42 Bq/Kg, 0.47 - 12.13 Bq/kg, 0.5 - 1.29 Bq/kg, 0.001 - 3.41 Bq/kg, 19.25 -2521.82 Bq/kg, 0.08 - 6.84 Bq/kg, 0.02 - 6.87 Bq/kg, 6.08 - 32.02 Bq/kg, 0.03 - 21. 53 Bq/kg, 0.92 - 26.77 Bq/kg, 0.91 - 1200 Bq/kg, 0.14 - 2.58 Bq/Kg, 0.03 - 9.65 Bq/kg, 0.03 - 9.65 Bq/kg and 0.82 - 5.27 Bq/kg respectively. High concentrations were typically found in portulaca, the lowest concentrations were found in barley and bread additives. The annual effective dose due to the different foodstuff estimated was found to be 2.78±0.44 mSv/y and 1.18±mSv/y for age categories 7-12 y and> 17y respectively. (Author)

  7. CY 1995 radiation dose reconciliation report and resulting CY 1996 dose estimate for the 324 nuclear facility

    International Nuclear Information System (INIS)

    Landsman, S.D.; Thornhill, R.E.; Peterson, C.A.

    1996-04-01

    In this report, the dose estimate for CY 1995 is reconciled by month wih actual doses received. Results of the reconciliation were used to revise estimates of worker dose for CY 1996. Resulting dose estimate for the facility is also included. Support for two major programs (B-Cell Cleanout and Surveillance and Maintenance) accounts for most of the exposure received by workers in the faility. Most of the expousre received by workers comes from work in the Radiochemical Engineering Complex airlock. In spite of schedule and work scope changes during CY 1995, dose estimates were close to actual exposures received. A number of ALARA measures were taken throughout the year; exposure reduction due to those was 20.6 Man-Rem, a 28% reduction from the CY 1995 estimate. Baseline estimates for various tasks in the facility were used to compile the CY 1996 dose estimate of 45.4 Man-Rem; facility goal for CY 1996 is to reduce worker dose by 20%, to 36.3 Man-Rem

  8. Illuminant color estimation based on pigmentation separation from human skin color

    Science.gov (United States)

    Tanaka, Satomi; Kakinuma, Akihiro; Kamijo, Naohiro; Takahashi, Hiroshi; Tsumura, Norimichi

    2015-03-01

    Human has the visual system called "color constancy" that maintains the perceptive colors of same object across various light sources. The effective method of color constancy algorithm was proposed to use the human facial color in a digital color image, however, this method has wrong estimation results by the difference of individual facial colors. In this paper, we present the novel color constancy algorithm based on skin color analysis. The skin color analysis is the method to separate the skin color into the components of melanin, hemoglobin and shading. We use the stationary property of Japanese facial color, and this property is calculated from the components of melanin and hemoglobin. As a result, we achieve to propose the method to use subject's facial color in image and not depend on the individual difference among Japanese facial color.

  9. MO-E-17A-04: Size-Specific Dose Estimate (SSDE) Provides a Simple Method to Calculate Organ Dose for Pediatric CT Examinations

    International Nuclear Information System (INIS)

    Moore, B; Brady, S; Kaufman, R; Mirro, A

    2014-01-01

    Purpose: Investigate the correlation of SSDE with organ dose in a pediatric population. Methods: Four anthropomorphic phantoms, representing a range of pediatric body habitus, were scanned with MOSFET dosimeters placed at 23 organ locations to determine absolute organ dosimetry. Phantom organ dosimetry was divided by phantom SSDE to determine correlation between organ dose and SSDE. Correlation factors were then multiplied by patient SSDE to estimate patient organ dose. Patient demographics consisted of 352 chest and 241 abdominopelvic CT examinations, 22 ± 15 kg (range 5−55 kg) mean weight, and 6 ± 5 years (range 4 mon to 23 years) mean age. Patient organ dose estimates were compared to published pediatric Monte Carlo study results. Results: Phantom effective diameters were matched with patient population effective diameters to within 4 cm. 23 organ correlation factors were determined in the chest and abdominopelvic region across nine pediatric weight subcategories. For organs fully covered by the scan volume, correlation in the chest (average 1.1; range 0.7−1.4) and abdominopelvic (average 0.9; range 0.7−1.3) was near unity. For organs that extended beyond the scan volume (i.e., skin, bone marrow, and bone surface), correlation was determined to be poor (average 0.3; range: 0.1−0.4) for both the chest and abdominopelvic regions, respectively. Pediatric organ dosimetry was compared to published values and was found to agree in the chest to better than an average of 5% (27.6/26.2) and in the abdominopelvic region to better than 2% (73.4/75.0). Conclusion: Average correlation of SSDE and organ dosimetry was found to be better than ± 10% for fully covered organs within the scan volume. This study provides a list of organ dose correlation factors for the chest and abdominopelvic regions, and describes a simple methodology to estimate individual pediatric patient organ dose based on patient SSDE

  10. MO-E-17A-04: Size-Specific Dose Estimate (SSDE) Provides a Simple Method to Calculate Organ Dose for Pediatric CT Examinations

    Energy Technology Data Exchange (ETDEWEB)

    Moore, B; Brady, S; Kaufman, R [St Jude Children' s Research Hospital, Memphis, TN (United States); Mirro, A [Washington University, St. Louis, MO (United States)

    2014-06-15

    Purpose: Investigate the correlation of SSDE with organ dose in a pediatric population. Methods: Four anthropomorphic phantoms, representing a range of pediatric body habitus, were scanned with MOSFET dosimeters placed at 23 organ locations to determine absolute organ dosimetry. Phantom organ dosimetry was divided by phantom SSDE to determine correlation between organ dose and SSDE. Correlation factors were then multiplied by patient SSDE to estimate patient organ dose. Patient demographics consisted of 352 chest and 241 abdominopelvic CT examinations, 22 ± 15 kg (range 5−55 kg) mean weight, and 6 ± 5 years (range 4 mon to 23 years) mean age. Patient organ dose estimates were compared to published pediatric Monte Carlo study results. Results: Phantom effective diameters were matched with patient population effective diameters to within 4 cm. 23 organ correlation factors were determined in the chest and abdominopelvic region across nine pediatric weight subcategories. For organs fully covered by the scan volume, correlation in the chest (average 1.1; range 0.7−1.4) and abdominopelvic (average 0.9; range 0.7−1.3) was near unity. For organs that extended beyond the scan volume (i.e., skin, bone marrow, and bone surface), correlation was determined to be poor (average 0.3; range: 0.1−0.4) for both the chest and abdominopelvic regions, respectively. Pediatric organ dosimetry was compared to published values and was found to agree in the chest to better than an average of 5% (27.6/26.2) and in the abdominopelvic region to better than 2% (73.4/75.0). Conclusion: Average correlation of SSDE and organ dosimetry was found to be better than ± 10% for fully covered organs within the scan volume. This study provides a list of organ dose correlation factors for the chest and abdominopelvic regions, and describes a simple methodology to estimate individual pediatric patient organ dose based on patient SSDE.

  11. Estimation of the fetal dose by dose measurement during an irradiation of a parotid tumor; Estimation de la dose foetale par mesure de dose lors d'une irradiation d'une tumeur de la parotide

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, V.; Graff-Cailleaud, P.; Peiffert, D. [Centre Alexis-Vautrin, 54 - Vandoeuvre-les-Nancy (France); Noel, A. [Institut National Polytechnique de Lorraine, CRAN CNRS UMR-7039, 54 - Vandoeuvre-les-Nancy (France)

    2006-11-15

    The irradiation of a five months pregnant patient has been made for a right parotid attack. In conformation with the legislative texts relative to radiation protection ( publication 84 of the ICRP) an estimation of the dose received for the fetus has been led by dose measurement on phantom. With the dose limit ( 100 mGy) recommended in the publication 84 of the ICRP neither modification of the treatment nor abortion was necessary. (N.C.)

  12. The D1 method: career dose estimation from a combination of historical monitoring data and a single year's dose data

    International Nuclear Information System (INIS)

    Sont, W.N.

    1995-01-01

    A method is introduced to estimate career doses from a combination of historical monitoring data and a single year's dose data. This method, called D1 eliminates the bias arising from incorporating historical dose data from times when occupational doses were generally much higher than they are today. Doses calculated by this method are still conditional on the preservation of the status quo in the effectiveness of radiation protection. The method takes into account the variation of the annual dose, and of the probability of being monitored, with the time elapsed since the start of a career. It also allows for the calculation of a standard error of the projected career dose. Results from recent Canadian dose data are presented. (author)

  13. Estimates of Health Detriments and Tissue Weighting Factors for Hong Kong Populations from Low Dose, Low Dose Rate and Low LET Ionising Radiation Exposure

    International Nuclear Information System (INIS)

    Lee, S.K.

    1998-01-01

    The total health detriments and the tissue weighting factors for the Hong Kong populations from low dose, low dose rate and low LET ionising radiation exposure are obtained according to the methodology recommended in ICRP Publication 60. The probabilities of fatal cancers for the general (ages 0-90) and working (ages 20-64) populations due to lifetime exposure at low dose and low dose rate are 4.9 x 10 -2 Sv -1 and 3.6 x 10 -2 Sv -1 respectively, comparing with the ICRP 60 estimates of 5.0 x 10 -2 Sv -1 and 4.0 x 10 -2 Sv -1 . The corresponding total health detriments for the general and working populations are 6.9 x 10 -2 Sv -1 and 4.9 x 10 -2 Sv -1 respectively comparing with the ICRP 60 estimates of 7.3 x 10 -2 Sv -1 and 5.6 x 10 -2 Sv -1 . Tissue weighting factors for the general population are 0.01 (bone surface and skin), 0.02 (liver, oesophagus and thyroid), 0.04 (bladder and breast), 0.08 (remainder), 0.10 (stomach), 0.11 (bone marrow), 0.15 (colon), 0.19 (lung) and 0.21 (gonads) and for the working population are 0.01 (bone surface and skin), 0.03 (liver, oesophagus and thyroid), 0.04 (breast), 0.06 (remainder), 0.07 (bladder), 0.08 (colon), 0.14 (bone marrow and stomach), 0.16 (lung) and 0.20 (gonads). (author)

  14. Estimates of radiation doses from various sources of exposure

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter provides an overview of radiation doses to individuals and to the collective US population from various sources of ionizing radiation. Summary tables present doses from various sources of ionizing radiation. Summary tables present doses from occupational exposures and annual per capita doses from natural background, the healing arts, nuclear weapons, nuclear energy and consumer products. Although doses from non-ionizing radiation are not as yet readily available in a concise form, the major sources of non-ionizing radiation are listed

  15. Estimating skin blood saturation by selecting a subset of hyperspectral imaging data

    Science.gov (United States)

    Ewerlöf, Maria; Salerud, E. Göran; Strömberg, Tomas; Larsson, Marcus

    2015-03-01

    Skin blood haemoglobin saturation (?b) can be estimated with hyperspectral imaging using the wavelength (λ) range of 450-700 nm where haemoglobin absorption displays distinct spectral characteristics. Depending on the image size and photon transport algorithm, computations may be demanding. Therefore, this work aims to evaluate subsets with a reduced number of wavelengths for ?b estimation. White Monte Carlo simulations are performed using a two-layered tissue model with discrete values for epidermal thickness (?epi) and the reduced scattering coefficient (μ's ), mimicking an imaging setup. A detected intensity look-up table is calculated for a range of model parameter values relevant to human skin, adding absorption effects in the post-processing. Skin model parameters, including absorbers, are; μ's (λ), ?epi, haemoglobin saturation (?b), tissue fraction blood (?b) and tissue fraction melanin (?mel). The skin model paired with the look-up table allow spectra to be calculated swiftly. Three inverse models with varying number of free parameters are evaluated: A(?b, ?b), B(?b, ?b, ?mel) and C(all parameters free). Fourteen wavelength candidates are selected by analysing the maximal spectral sensitivity to ?b and minimizing the sensitivity to ?b. All possible combinations of these candidates with three, four and 14 wavelengths, as well as the full spectral range, are evaluated for estimating ?b for 1000 randomly generated evaluation spectra. The results show that the simplified models A and B estimated ?b accurately using four wavelengths (mean error 2.2% for model B). If the number of wavelengths increased, the model complexity needed to be increased to avoid poor estimations.

  16. Dose dependence on stochastic radiobiological effect in radiation risk estimation

    International Nuclear Information System (INIS)

    Komochkov, M.M.

    1999-01-01

    The analysis of the results in dose -- effect relationship observation has been carried out on the cell and organism levels, with the aim to obtain more precise data on the risk coefficients at low doses. The results are represented by two contrasting groups of dose dependence on effect: a downwards concave and a J-shaped curve. Both types of dependence are described by the equation solutions of an assumed unified protective mechanism, which comprises two components: constitutive and adaptive or inducible ones. The latest data analysis of the downwards concave dependence curves shows a considerable underestimation of radiation risk in all types of cancer, except leukemia, for a number of critical groups in a population, at low doses comparing to the ICRP recommendations. With the dose increase, the decrease of the effect value per dose unit is observed. It may be possibly related to the switching of the activity of the adaptive protective mechanism, with some threshold dose values being exceeded

  17. Estimate of 50-year dose commitment to various organs and tissues of the body from inhalation of 222Rn free of its daughters

    International Nuclear Information System (INIS)

    Bernard, S.R.; Ford, M.R.; Snyder, W.S.

    1976-01-01

    Some topics discussed are as follows: retention of 222 Rn in fat, bone, heart, muscle, skin, testes, and urinary bladder; retention equations for Rn; decay scheme for Rn and 226 Ra; metabolic models for Po, Pb, and Bi; dose estimates to target organs for 222 Rn and its daughters that are not inhaled but produced from decay of 222 Rn; and estimation of MPC for bone marrow, gonads, and total body

  18. ICRP-26 and skin contamination

    International Nuclear Information System (INIS)

    Finnigan, T.; Huda, W.; Newbery, G.R.

    1979-01-01

    The experience of dealing with skin contamination incidents at The Radiochemical Centre over a 3-year period is presented. Data are given for the primary isotopes involved, the duration of skin contamination, and the skin doses that arise from these incidents. The methods employed in performing dosimetry for skin contamination are discussed and examples involving the isotopes carbon-14 and indium-111 are described. For skin contamination incidents, the mode of penetration of the activity into skin is normally not known and this can be of major significance for the final skin dose estimate. The operational health physics difficulties encountered in complying with both ICRP-26 and UK legislation for skin contamination are considered. In the event of multiple exposure (i.e. skin doses calculated from whole body film badges, extremity TLD dose meters and skin contamination) there is ambiguity in the precise meaning of the skin dose. The usefulness of Derived Working Levels is also discussed. Experience at The Radiochemical Centre has shown that good plant design, proper training and prompt action in dealing with contamination incidents ensures that overexposures to skin from accidental contamination are rare occurrences. (author)

  19. Construction of boundary-surface-based Chinese female astronaut computational phantom and proton dose estimation

    International Nuclear Information System (INIS)

    Sun Wenjuan; Xie Tianwu; Liu Qian; Jia Xianghong; Xu Feng

    2013-01-01

    With the rapid development of China's space industry, the importance of radiation protection is increasingly prominent. To provide relevant dose data, we first developed the Visible Chinese Human adult Female (VCH-F) phantom, and performed further modifications to generate the VCH-F Astronaut (VCH-FA) phantom, incorporating statistical body characteristics data from the first batch of Chinese female astronauts as well as reference organ mass data from the International Commission on Radiological Protection (ICRP; both within 1% relative error). Based on cryosection images, the original phantom was constructed via Non-Uniform Rational B-Spline (NURBS) boundary surfaces to strengthen the deformability for fitting the body parameters of Chinese female astronauts. The VCH-FA phantom was voxelized at a resolution of 2 x 2 x 4 mm 3 for radioactive particle transport simulations from isotropic protons with energies of 5000 - 10 000 MeV in Monte Carlo N-Particle eXtended (MCNPX) code. To investigate discrepancies caused by anatomical variations and other factors, the obtained doses were compared with corresponding values from other phantoms and sex-averaged doses. Dose differences were observed among phantom calculation results, especially for effective dose with low-energy protons. Local skin thickness shifts the breast dose curve toward high energy, but has little impact on inner organs. Under a shielding layer, organ dose reduction is greater for skin than for other organs. The calculated skin dose per day closely approximates measurement data obtained in low-Earth orbit (LEO). (author)

  20. Single-Dose Azithromycin for the Treatment of Haemophilus ducreyi Skin Ulcers in Papua New Guinea.

    Science.gov (United States)

    González-Beiras, Camila; Kapa, August; Vall-Mayans, Marti; Paru, Raymond; Gavilán, Sergi; Houinei, Wendy; Bieb, Sibauk; Sanz, Sergi; Martins, Rosario; Mitjà, Oriol

    2017-11-29

    Haemophilus ducreyi (HD) and Treponema pallidum subspecies pertenue (TP) are major causative agents of cutaneous ulcer (CU) in the tropics. Azithromycin is recommended to treat sexually transmitted HD infections and has good in vitro activity against HD strains from both genital and skin ulcers. We investigated the efficacy of oral single-dose azithromycin on HD-CU. We conducted a community-based cohort study in Lihir Island, Papua New Guinea, from October 2014 through May 2016. Consenting patients with skin ulcers >1 cm in diameter were eligible for this study and had collected a lesional swab for polymerase chain reaction (PCR). All participants were treated with single-dose azithromycin (30 mg/kg) and were followed up for assessment of clinical resolution. We retrospectively classified patients according to PCR results into HD, TP, and PCR-negative groups. The primary endpoint was healing rates of HD-CU at 14 days after treatment. We obtained full outcome data from 246 patients; 131 (53.3%) were HD PCR positive, 37 (15.0%) were TP positive, and 78 (31.7%) were negative for all tests. Healing rates were 88.5% (95% confidence interval [CI], .82-.93) in the HD group, 78.4% [95% CI, .63-.89] in the TP group, and 74.4% (95% CI, .64-.83) in the PCR-negative group. If we included the participants with improved ulcers, the healing rates increased to 94.7%, 97.3%, and 89.7% respectively. HD cases classified as not healed all converted to HD-negative PCR. Based upon clinical resolution and PCR conversion to HD negative, a single oral dose of azithromycin is efficacious for the treatment of HD-CU. These results have implications for the treatment of individual patients and for the use of antibiotics in public health strategies to control CU in the tropics. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  1. Evaluating low dose ionizing radiation effects on gene expression in human skin biopsy cores

    International Nuclear Information System (INIS)

    Goldberg, Z.; Schwietert, C.; Stern, R.L.; Lehnert, B.E.

    2003-01-01

    Significant biological effects can occur in animals, animal cells, immortalized human cell lines, and primary human cells after exposure to doses of ionizing radiation (IR) in the <1-10 cGy region. However it is unclear how these observations mimic or even pertain to the actual in vivo condition in humans, though such knowledge is required for reducing the uncertainty of assessing human risks due to low dose IR (LDIR) exposures. Further, low dose effects have increasing clinical relevance in the radiotherapeutic management of cancer as the volume of tissue receiving only LDIR increases as more targeted radiotherapy (i.e. IMRT) becomes more widely used. Thus, human translational data must be obtained with which to correlate in vitro experimental findings and evaluate their 'real-life' applicability. To evaluate LDIR effects in human tissue we have obtained freshly explanted full thickness human skin samples obtained from aesthetic surgery, and subjected them to ex vivo irradiation as a translational research model system of a complex human tissue. Ionizing radiation (IR) exposures were delivered at 1, 10, or 100 cGy. The temporal response to IR was assessed by harvesting RNA at multiple time points out to 24 hours post IR. Gene expression changes were assessed by real time PCR. We have shown that RNA can be reliably extracted with fidelity from 3 mm diameter punch biopsies of human tissue and provide good quality sample for the real time PCR evaluation. Genes of interest include those reported to have altered expression following LDIR from in vitro cell culture models. These include genes associated with cell cycle regulation, DNA repair and various cytokines. These feasibility studies in human skin irradiated ex vivo, have demonstrated that gene expression can be measured accurately from very small human tissue samples, thus setting the stage for biopsy acquisition of tissue irradiated in vivo from patients-volunteers. The clinical study has begun and the data from

  2. Skin dose and response for the head and neck in patients irradiated with x-ray for tinea capitis: implications for environmental radioactivity

    International Nuclear Information System (INIS)

    Harley, N.H.; Kolber, A.B.; Shore, R.E.; Albert, R.E.; Altman, S.M.; Pasternack, B.S.

    1983-01-01

    The dose delivered to the skin of the head and neck in patients treated with x-ray irradiation for childhood tinea capitis was reconstructed. This was possible by utilizing a phantom made from the skull of a seven year old child and irradiating it with the same technique and x-ray machine used in tinea capitis therapy two to four decades ago. Seventy-eight basal cell carcinomas (BCC) have appeared so far in 40 of 1727 irradiated white children and none in 500 irradiated black children. The dose distribution over the face and scalp is used to estimate the risk of BCC per person per rad. These results must be considered preliminary due to the relatively young age of the irradiated group (<50 years) at the present time. From the decreased risk per rad for the portion of the scalp that is hair covered, it appears that environmental ultraviolet radiation may play a key role in the expression of BCC. A cumulative hazard plot is utilized to tentatively extend the data to lifetime risk of 0.003 per rad with an upper limit of 0.006 per rad. Environmental radiation dose to the skin possibly account for 20% of observed BCC if this tentative risk estimate is valid

  3. SU-E-I-55: The Contribution to Skin Dose Due to Scatter From the Patient Table and the Head Holder During Fluoroscopy

    International Nuclear Information System (INIS)

    Islam, N; Xiong, Z; Vijayan, S; Rudin, S; Bednarek, D

    2015-01-01

    Purpose: To determine contributions to skin dose due to scatter from the table and head holder used during fluoroscopy, and also to explore alternative design material to reduce the scatter dose. Methods: Measurements were made of the primary and scatter components of the xray beam exiting the patient table and a cylindrical head holder used on a Toshiba Infinix c-arm unit as a function of kVp for the various beam filters on the machine and for various field sizes. The primary component of the beam was measured in air with the object placed close to the x-ray tube with an air gap between it and a 6 cc parallel-plate ionization chamber and with the beam collimated to a size just larger than the chamber. The primary plus scatter radiation components were measured with the object moved to a position in the beam next to the chamber for larger field sizes. Both sets of measurements were preformed while keeping the source-to-chamber distance fixed. The scatter fraction was estimated by taking the ratio of the difference between the two measurements and the reading that included both primary and scatter. Similar measurements were also made for a 2.3 cm thick Styrofoam block which could substitute for the patient support. Results: The measured scatter fractions indicate that the patient table as well as the head holder contributes an additional 10–16% to the patient entrance dose depending on field size. Forward scatter was reduced with the Styrofoam block so that the scatter fraction was about 4–5%. Conclusion: The results of this investigation demonstrated that scatter from the table and head holder used in clinical fluoroscopy contribute substantially to the skin dose. The lower contribution of scatter from Styrofoam suggests that there is an opportunity to redesign patient support accessories to reduce the skin dose. Partial support from NIH grant R01EB002873 and Toshiba Medical Systems Corporation Equipment Grant

  4. SU-E-I-55: The Contribution to Skin Dose Due to Scatter From the Patient Table and the Head Holder During Fluoroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Islam, N; Xiong, Z; Vijayan, S; Rudin, S; Bednarek, D [Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY (United States)

    2015-06-15

    Purpose: To determine contributions to skin dose due to scatter from the table and head holder used during fluoroscopy, and also to explore alternative design material to reduce the scatter dose. Methods: Measurements were made of the primary and scatter components of the xray beam exiting the patient table and a cylindrical head holder used on a Toshiba Infinix c-arm unit as a function of kVp for the various beam filters on the machine and for various field sizes. The primary component of the beam was measured in air with the object placed close to the x-ray tube with an air gap between it and a 6 cc parallel-plate ionization chamber and with the beam collimated to a size just larger than the chamber. The primary plus scatter radiation components were measured with the object moved to a position in the beam next to the chamber for larger field sizes. Both sets of measurements were preformed while keeping the source-to-chamber distance fixed. The scatter fraction was estimated by taking the ratio of the difference between the two measurements and the reading that included both primary and scatter. Similar measurements were also made for a 2.3 cm thick Styrofoam block which could substitute for the patient support. Results: The measured scatter fractions indicate that the patient table as well as the head holder contributes an additional 10–16% to the patient entrance dose depending on field size. Forward scatter was reduced with the Styrofoam block so that the scatter fraction was about 4–5%. Conclusion: The results of this investigation demonstrated that scatter from the table and head holder used in clinical fluoroscopy contribute substantially to the skin dose. The lower contribution of scatter from Styrofoam suggests that there is an opportunity to redesign patient support accessories to reduce the skin dose. Partial support from NIH grant R01EB002873 and Toshiba Medical Systems Corporation Equipment Grant.

  5. Evaluation of skin surface dose for head and neck cancer patients treated with intensity-modulated radiation therapy using in vivo dosimetry

    International Nuclear Information System (INIS)

    Kim, Yeon Sil; Lee, Dong Soo; Yoo, Mi Na; Hong, Joo Young; Yoon, Se Chul; Jang, Hong Suk

    2011-01-01

    Use of intensity-modulated radiation therapy (IMRT) for head and neck cancer is gradually increasing, because it could facilitate more sophsticated treatment of target volumes and reduction of acute and late sequelae. However, theoretically, there is a potential risk of increased skin surface dose resulting from multiple obliquity effects caused by multiple tangential beams. Moreover, we sometimes confronted with more skin reactions in the patients treated with IMRT than conventional techniques. In this study, we evaluated skin surface dose adjacent to the target volumes to verify whether the use of IMRT would increase the skin dose more than we predicted. This study had shown that the use of IMRT did not increase the skin surface hot point dose. The measured skin surface dose was 20 to 40 percent of the adjacent target prescription dose, and was within acceptable dose range. Our study had some limitations with small number of experimental patients and methodological problems. Potential risk of increasing skin dose with bolus effect of aquaplaster should be examined in the future trials. In addition, the accurate set-up verification should be maintained because of steep dose gradient between skin surface and target volumes within a short distance in the head and neck cancer patients.

  6. Electron contamination modeling and skin dose in 6 MV longitudinal field MRIgRT: Impact of the MRI and MRI fringe field

    International Nuclear Information System (INIS)

    Oborn, B. M.; Metcalfe, P. E.; Butson, M. J.; Rosenfeld, A. B.; Keall, P. J.

    2012-01-01

    Purpose: In recent times, longitudinal field MRI-linac systems have been proposed for 6 MV MRI-guided radiotherapy (MRIgRT). The magnetic field is parallel with the beam axis and so will alter the transport properties of any electron contamination particles. The purpose of this work is to provide a first investigation into the potential effects of the MR and fringe magnetic fields on the electron contamination as it is transported toward a phantom, in turn, providing an estimate of the expected patient skin dose changes in such a modality. Methods: Geant4 Monte Carlo simulations of a water phantom exposed to a 6 MV x-ray beam were performed. Longitudinal magnetic fields of strengths between 0 and 3 T were applied to a 30 x 30 x 20 cm 3 phantom. Surrounding the phantom there is a region where the magnetic field is at full MRI strength, consistent with clinical MRI systems. Beyond this the fringe magnetic field entering the collimation system is also modeled. The MRI-coil thickness, fringe field properties, and isocentric distance are varied and investigated. Beam field sizes of 5 x 5, 10 x 10, 15 x 15 and 20 x 20 cm 2 were simulated. Central axis dose, 2D virtual entry skin dose films, and 70 μm skin depth doses were calculated using high resolution scoring voxels. Results: In the presence of a longitudinal magnetic field, electron contamination from the linear accelerator is encouraged to travel almost directly toward the patient surface with minimal lateral spread. This results in a concentration of electron contamination within the x-ray beam outline. This concentration is particularly encouraged if the fringe field encompasses the collimation system. Skin dose increases of up to 1000% were observed for certain configurations and increases above Dmax were common. In nonmagnetically shielded cases, electron contamination generated from the jaw faces and air column is trapped and propagated almost directly to the phantom entry region, giving rise to intense dose

  7. Electron contamination modeling and skin dose in 6 MV longitudinal field MRIgRT: Impact of the MRI and MRI fringe field.

    Science.gov (United States)

    Oborn, B M; Metcalfe, P E; Butson, M J; Rosenfeld, A B; Keall, P J

    2012-02-01

    In recent times, longitudinal field MRI-linac systems have been proposed for 6 MV MRI-guided radiotherapy (MRIgRT). The magnetic field is parallel with the beam axis and so will alter the transport properties of any electron contamination particles. The purpose of this work is to provide a first investigation into the potential effects of the MR and fringe magnetic fields on the electron contamination as it is transported toward a phantom, in turn, providing an estimate of the expected patient skin dose changes in such a modality. Geant4 Monte Carlo simulations of a water phantom exposed to a 6 MV x-ray beam were performed. Longitudinal magnetic fields of strengths between 0 and 3 T were applied to a 30 × 30 × 20 cm(3) phantom. Surrounding the phantom there is a region where the magnetic field is at full MRI strength, consistent with clinical MRI systems. Beyond this the fringe magnetic field entering the collimation system is also modeled. The MRI-coil thickness, fringe field properties, and isocentric distance are varied and investigated. Beam field sizes of 5 × 5, 10 × 10, 15 × 15 and 20 × 20 cm(2) were simulated. Central axis dose, 2D virtual entry skin dose films, and 70 μm skin depth doses were calculated using high resolution scoring voxels. In the presence of a longitudinal magnetic field, electron contamination from the linear accelerator is encouraged to travel almost directly toward the patient surface with minimal lateral spread. This results in a concentration of electron contamination within the x-ray beam outline. This concentration is particularly encouraged if the fringe field encompasses the collimation system. Skin dose increases of up to 1000% were observed for certain configurations and increases above Dmax were common. In nonmagnetically shielded cases, electron contamination generated from the jaw faces and air column is trapped and propagated almost directly to the phantom entry region, giving rise to intense

  8. In situ biological dose mapping estimates the radiation burden delivered to 'spared' tissue between synchrotron X-ray microbeam radiotherapy tracks.

    Directory of Open Access Journals (Sweden)

    Kai Rothkamm

    Full Text Available Microbeam radiation therapy (MRT using high doses of synchrotron X-rays can destroy tumours in animal models whilst causing little damage to normal tissues. Determining the spatial distribution of radiation doses delivered during MRT at a microscopic scale is a major challenge. Film and semiconductor dosimetry as well as Monte Carlo methods struggle to provide accurate estimates of dose profiles and peak-to-valley dose ratios at the position of the targeted and traversed tissues whose biological responses determine treatment outcome. The purpose of this study was to utilise γ-H2AX immunostaining as a biodosimetric tool that enables in situ biological dose mapping within an irradiated tissue to provide direct biological evidence for the scale of the radiation burden to 'spared' tissue regions between MRT tracks. Γ-H2AX analysis allowed microbeams to be traced and DNA damage foci to be quantified in valleys between beams following MRT treatment of fibroblast cultures and murine skin where foci yields per unit dose were approximately five-fold lower than in fibroblast cultures. Foci levels in cells located in valleys were compared with calibration curves using known broadbeam synchrotron X-ray doses to generate spatial dose profiles and calculate peak-to-valley dose ratios of 30-40 for cell cultures and approximately 60 for murine skin, consistent with the range obtained with conventional dosimetry methods. This biological dose mapping approach could find several applications both in optimising MRT or other radiotherapeutic treatments and in estimating localised doses following accidental radiation exposure using skin punch biopsies.

  9. Biological dose estimation and comet analysis of the victims in a high dose 60Co radiation accident

    International Nuclear Information System (INIS)

    Chen Ying; Liu Xiulin; Luo Yisheng; Li You; Yao Bo

    2007-01-01

    Objective: To explore the methods of chromosome preparation in human peripheral blood and bone marrow after very high dose exposure and fit the dose-response curve of dicentrics and tings in the range of high doses over 6 Gy for estimating biological dose and detecting DNA damage in the victims of '10.21' accident. Methods: The samples of peripheral blood and bone marrow in 2 victims were collected to prepare chromosome mataphases and dicentrics (multicentrics) + rings were counted. The dose-response curve and equation of human blood irradiated between 6-22 Gy in vitro were established and applied to assess biological dose of 2 victims. In addition, their DNA damages were tested by alkaline single cell gel electrophoresis. Results: The dicentric + ring numbers of 4.47 per cell in victims B's peripheral blood lymphocytes and 9.15 per cell in victim A's bone marrow who had no mitosis in peripheral blood cell. The whole body average doses of victims B and A estimated by 6-22 Gy equation arrived at 9.4 Gy and 19.5 Gy, respectively. The serious DNA damages were expressed by small head and large tail comet figures. Conclusions: The biological doses of 2 victims estimated by 6-22 Gy dose-response curve have reached the levels of extreme grave bone marrow and intestinal ARS, respectively. (authors)

  10. Skin

    International Nuclear Information System (INIS)

    Hunter, R.D.

    1985-01-01

    Malignant disease involving the skin represents a significant work load to the general radiotherapist and can involve interesting diagnostic and therapeutic decisions. Primary skin cancer is also relatively common and there is a need to provide an efficient service in which the first treatment is successful in the majority of patients. The reward for careful attention to technique is very considerable both in terms of clinical cancer control and functional results. Squamous cell carcinoma, basal cell carcinoma, and intra-epidermal carcinoma constitute the majority of the lesions dealt with clinically, but metastatic disease, lymphomas, and malignant melanomas are also referred regularly for opinions and may require radiotherapy. The general principle of the techniques of assessment and radiotherapeutic management to be described are equally applicable to any malignant skin tumour once the decision has been made to accept it for radiotherapy. Dosage and fractionation may have to be adjusted to allow for the nature of the disease process and the intent of the treatment

  11. Estimating the effective radiation dose imparted to patients by intraoperative cone-beam computed tomography in thoracolumbar spinal surgery.

    Science.gov (United States)

    Lange, Jeffrey; Karellas, Andrew; Street, John; Eck, Jason C; Lapinsky, Anthony; Connolly, Patrick J; Dipaola, Christian P

    2013-03-01

    Observational. To estimate the radiation dose imparted to patients during typical thoracolumbar spinal surgical scenarios. Minimally invasive techniques continue to become more common in spine surgery. Computer-assisted navigation systems coupled with intraoperative cone-beam computed tomography (CT) represent one such method used to aid in instrumented spinal procedures. Some studies indicate that cone-beam CT technology delivers a relatively low dose of radiation to patients compared with other x-ray-based imaging modalities. The goal of this study was to estimate the radiation exposure to the patient imparted during typical posterior thoracolumbar instrumented spinal procedures, using intraoperative cone-beam CT and to place these values in the context of standard CT doses. Cone-beam CT scans were obtained using Medtronic O-arm (Medtronic, Minneapolis, MN). Thermoluminescence dosimeters were placed in a linear array on a foam-plastic thoracolumbar spine model centered above the radiation source for O-arm presets of lumbar scans for small or large patients. In-air dosimeter measurements were converted to skin surface measurements, using published conversion factors. Dose-length product was calculated from these values. Effective dose was estimated using published effective dose to dose-length product conversion factors. Calculated dosages for many full-length procedures using the small-patient setting fell within the range of published effective doses of abdominal CT scans (1-31 mSv). Calculated dosages for many full-length procedures using the large-patient setting fell within the range of published effective doses of abdominal CT scans when the number of scans did not exceed 3. We have demonstrated that single cone-beam CT scans and most full-length posterior instrumented spinal procedures using O-arm in standard mode would likely impart a radiation dose within the range of those imparted by a single standard CT scan of the abdomen. Radiation dose increases

  12. Evaluation of skin entrance radiation dose in pediatric patients undergoing chest X-rays exams

    International Nuclear Information System (INIS)

    Gabardo, Farly Piantini

    2016-01-01

    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)

  13. Calibration of Kodak EDR2 film for patient skin dose assessment in cardiac catheterization procedures.

    Science.gov (United States)

    Morrell, Rachel E; Rogers, Andy

    2004-12-21

    Kodak EDR2 film has been calibrated across the range of exposure conditions encountered in our cardiac catheterization laboratory. Its dose-response function has been successfully modelled, up to the saturation point of 1 Gy. The most important factor affecting film sensitivity is the use of beam filtration. Spectral filtration and kVp together account for a variation in dose per optical density of -10% to +25%, at 160 mGy. The use of a dynamic wedge filter may cause doses to be underestimated by up to 6%. The film is relatively insensitive to variations in batch, field size, exposure rate, time to processing and day-to-day fluctuations in processor performance. Overall uncertainty in the calibration is estimated to be -20% to +40%, at 160 mGy. However, the uncertainty increases at higher doses, as the curve saturates. Artefacts were seen on a number of films, due to faults in the light-proofing of the film packets.

  14. Simple approximation for estimating centerline gamma absorbed dose rates due to a continuous Gaussian plume

    International Nuclear Information System (INIS)

    Overcamp, T.J.; Fjeld, R.A.

    1987-01-01

    A simple approximation for estimating the centerline gamma absorbed dose rates due to a continuous Gaussian plume was developed. To simplify the integration of the dose integral, this approach makes use of the Gaussian cloud concentration distribution. The solution is expressed in terms of the I1 and I2 integrals which were developed for estimating long-term dose due to a sector-averaged Gaussian plume. Estimates of tissue absorbed dose rates for the new approach and for the uniform cloud model were compared to numerical integration of the dose integral over a Gaussian plume distribution

  15. Effective dose estimation to patients and staff during urethrography procedures

    International Nuclear Information System (INIS)

    Sulieman, A.; Barakat, H.; Alkhorayef, M.; Babikir, E.; Dalton, A.; Bradley, D.

    2015-10-01

    Medical-related radiation is the largest source of controllable radiation exposure to humans and it accounts for more than 95% of radiation exposure from man-made sources. Few data were available worldwide regarding patient and staff dose during urological ascending urethrography (ASU) procedure. The purposes of this study are to measure patient and staff entrance surface air kerma dose (ESAK) during ASU procedure and evaluate the effective doses. A total of 243 patients and 145 staff (Urologist) were examined in three Hospitals in Khartoum state. ESAKs were measured for patient and staff using thermoluminescent detectors (TLDs). Effective doses (E) were calculated using published conversion factors and methods recommended by the national Radiological Protection Board (NRPB). The mean ESAK dose for patients and staff dose were 7.79±6.7 mGy and 0.161±0.30 mGy per procedures respectively. The mean and range of the effective dose was 1.21 mSv per procedure. The radiation dose in this study is comparable with previous studies except Hospital C. It is obvious that high patient and staff exposure is due to the lack of experience and protective equipment s. Interventional procedures remain operator dependent; therefore continuous training is crucial. (Author)

  16. Effective dose estimation to patients and staff during urethrography procedures

    Energy Technology Data Exchange (ETDEWEB)

    Sulieman, A. [Prince Sattam bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P. O- Box 422, Alkharj 11942 (Saudi Arabia); Barakat, H. [Neelain University, College of Science and Technology, Medical Physics Department, Khartoum (Sudan); Alkhorayef, M.; Babikir, E. [King Saud University, College of Applied Sciences, Radiological Sciences Department, P. O. Box 10219, Riyadh 11433 (Saudi Arabia); Dalton, A.; Bradley, D. [University of Surrey, Centre for Nuclear and Radiation Physics, Department of Physics, Surrey, GU2 7XH Guildford (United Kingdom)

    2015-10-15

    Medical-related radiation is the largest source of controllable radiation exposure to humans and it accounts for more than 95% of radiation exposure from man-made sources. Few data were available worldwide regarding patient and staff dose during urological ascending urethrography (ASU) procedure. The purposes of this study are to measure patient and staff entrance surface air kerma dose (ESAK) during ASU procedure and evaluate the effective doses. A total of 243 patients and 145 staff (Urologist) were examined in three Hospitals in Khartoum state. ESAKs were measured for patient and staff using thermoluminescent detectors (TLDs). Effective doses (E) were calculated using published conversion factors and methods recommended by the national Radiological Protection Board (NRPB). The mean ESAK dose for patients and staff dose were 7.79±6.7 mGy and 0.161±0.30 mGy per procedures respectively. The mean and range of the effective dose was 1.21 mSv per procedure. The radiation dose in this study is comparable with previous studies except Hospital C. It is obvious that high patient and staff exposure is due to the lack of experience and protective equipment s. Interventional procedures remain operator dependent; therefore continuous training is crucial. (Author)

  17. Analysis of the suitableness of some enzymatic tests for estimation the degree of radiational injury of skin

    International Nuclear Information System (INIS)

    Matyushichev, V.B.; Kornikov, V.V.; Taratukhin, V.R.; Timofeeva, O.E.; Vereshchagina, E.M.

    1981-01-01

    Possibilities to characterize the degree of skin injury of white male-rats on the 14th day after external 85 Kr #betta#-irradiation at 3, 4, 5, 6, 7, 8, 9, 10 krad doses by activity levels of alkali and acid DNA-ases of skin and blood plasma as well as skin and plasma alpha-amylase have been studied using the methods of factor analysis. It has been ascertained that alkali and acid DNA-ases of skin have the best indicating properties. Other tests in the main only supplement the general picture. The combined accounting of properties of alkali and acid DNA-ases of skin as well as acid DNA-ase and alpha-amylase of blood plasma permits to demarkate individuals completely according to the degree (zero - 3d) of skin injuries. These indicators can be used in practical dosimetry

  18. Personal dose estimations for Olympic Dam's first year of production

    International Nuclear Information System (INIS)

    Sonter, M.; Hondros, J.

    1989-01-01

    Underground development activities have been underway at Olympic Dam since 1983; commercial ore extraction commenced in early 1988; and the metallurgical treatment plant commenced operation in mid 1988. Detailed and extensive radiation monitoring programs have been in place since commencement of activities and have enabled detailed individual assessment of personal doses. Results are shown, in histogram form, of doses to full and part-time underground mine workers pre-1988 and for calendar 1988; and projected annual doses to treatment plant workers for the period July 1988 to July 1989. Comments are included on the dose calculation assumptions applying in mine and mill and on the degree of conservatism of these assumptions. The doses presented show compliance with the limits quoted in the Australian code of practice; they compare well with other underground uranium mines, and they indicate effective pursuit of the 'alara' principle. 7 figs., 1 tab

  19. Radiotherapy verification film for estimating cumulative entrance skin exposure for fluoroscopic examinations

    International Nuclear Information System (INIS)

    Geise, R.A.; Ansel, H.J.

    1990-01-01

    Measurement of skin entrance exposures during fluoroscopic procedures is complicated by the use of automatic exposure control devices and the presence of contrast media. Due to variability in positioning spot films from patient to patient, standard dosimeters, such as thermoluminescent, cannot be properly placed on the skin prior to examination. Prepackaged film of the type used for portal verification in radiation therapy held next to the patient's skin in a specially modified patient examination gown was found to be useful for determining the entrance skin exposure from both fluoroscopy and spot films during air contrast barium enema exams. The usable sensitivity range of this film has been found satisfactory for exposure measurements at exposures and kVps typically used for gastrointestinal fluoroscopic procedures. Errors in exposure estimates due to changes in film speed and contrast with kVp are less than 5% for the range of kVps used. Errors from variations in beam quality due to the adjacency of scattering material are approximately 5%. Entrance exposures determined with film agreed with those determined from TLD measurements to within 21%, with an average difference of 9%

  20. Automated Estimation of Melanocytic Skin Tumor Thickness by Ultrasonic Radiofrequency Data.

    Science.gov (United States)

    Andrekute, Kristina; Valiukeviciene, Skaidra; Raisutis, Renaldas; Linkeviciute, Gintare; Makstiene, Jurgita; Kliunkiene, Renata

    2016-05-01

    High-frequency (>20-MHz) ultrasound (US) is a noninvasive preoperative tool for assessment of melanocytic skin tumor thickness. Ultrasonic melanocytic skin tumor thickness estimation is not always easy and is related to the experience of the clinician. In this article, we present an automated thickness measurement method based on time-frequency analysis of US radiofrequency signals. The study was performed on 52 thin (≤1-mm) melanocytic skin tumors (46 melanocytic nevi and 6 melanomas). Radiofrequency signals were obtained with a single-element focused transducer (fundamental frequency, 22 MHz; bandwidth, 12-28 MHz). The radiofrequency data were analyzed in the time-frequency domain to make the tumor boundaries more noticeable. The thicknesses of the tumors were evaluated by 3 different metrics: histologically measured Breslow thickness, manually measured US thickness, and automatically measured US thickness. The results showed a higher correlation coefficient between the automatically measured US thickness and Breslow thickness (r= 0.83; Pmeasured US thickness (r = 0.68; P measurement algorithm was 96.55%, and the specificity was 78.26% compared with histologic measurement. The sensitivity of the manually measured US thickness was 75.86%, and the specificity was 73.91%. The efficient automated tumor thickness measurement method developed could be used as a tool for preoperative assessment of melanocytic skin tumor thickness. © 2016 by the American Institute of Ultrasound in Medicine.

  1. Estimation of effective dose from limited cone beam X-ray CT examination

    Energy Technology Data Exchange (ETDEWEB)

    Iwai, Kazuo; Arai, Yoshinori; Hashimoto, Koji [Nihon Univ., Tokyo (Japan). School of Dentistry; Nishizawa, Kanae

    2000-12-01

    The limited cone beam X-ray CT (Ortho-CT) was developed on the basis of multi-functional panoramic apparatus, SCANORA (Soredex Co. Helsinki Finland). The imaging intensifier (I.I.) was built in this apparatus as a X-ray detection device instead of X-ray film. The signal provided from I.I. was converted from analog into digital by an analog-digital converter and image reconstitution was done as a three-directional image of the dimensions 3.8 cm of width, 3.0 cm height and 3.8 cm depth with the personal computer. The 3DX Multi image micro CT'' (3DX) was developed along similar lines by MORITA Co., Ltd. (Kyoto, JAPAN). In this study, the stochastic effect on organ and tissue caused by examinations using Ortho-CT and 3DX was measured. The effective dose was estimated according to the recommendation of ICRP60 and was compared with those of panoramic radiography and computed tomography. The irradiation conditions were as follows: 85 kV, 10 mA with the filtration of 3 mmAl and added 1 mmCu for Ortho-CT, and 80 kV, 2 mA and the filtration of 3.1 mmAL for 3DX. The measurement of organ and tissue dose was performed using an anthropomorphic Rando woman phantom (Alderson Research Laboratories Co., Stanfora, CN), as well as by using two different type of thermoluminescent dosimeter (TLD); Panasonic UD-170A (BeO) and UD-110S (CaSO{sub 4}: Tm). The UD-170A was for dose measurement of the inner useful X-ray beams, while the UD-110S was for outer beams. The measured organ and tissue were those recommended with ICRP60 (gonad, breast, bone marrow, lung, thyroid gland, esophagus, stomach, colon, liver, bladder, skin, brain, thymus, adrenal, kidney, spleen, pancrease, upper large intestine, uterus, eyes and major salivary gland). The imaging by Orhto-CT was made in the left maxillary 1st molar, left mandibular 1st molar and temporomandibular joint. 3DX measurement was made in the maxillary incisor region and middle ear regions other than the regions mentioned above. The skin

  2. Implication of new CEC recommendations for individual monitoring for external radiation doses to the skin and the extremities

    International Nuclear Information System (INIS)

    Christensen, P.; Julius, H.W.; Marshall, T.O.

    1991-01-01

    A drafting group consisting of the above authors has assisted the CEC in revising the CEC document Technical Recommendations for Monitoring the Exposure to Individuals to External Radiation, EUR 5287, published in 1975. The paper highlights sections of the revised version relating particularly to irradiation of the skin and the extremities and focusses on problems connected to exposure to weakly penetrating radiations. Concepts of individual monitoring for external radiation exposures to the skin of the whole body and to the extremities are discussed and guidance is given as regards dose quantities and dosemeter calibration procedures. A method of quantifying the overall accuracy of the dose measurements as a result of the various uncertainty components connected with the dosimetry system is suggested and requirements on the accuracy of the dose measurements complying with the ICRP requirements on overall accuracy for individual monitoring are specified. Moreover, implications of the accuracy requirements for the design and type testing of the dosemeter are discussed. (author)

  3. Model-based approach for quantitative estimates of skin, heart, and lung toxicity risk for left-side photon and proton irradiation after breast-conserving surgery.

    Science.gov (United States)

    Tommasino, Francesco; Durante, Marco; D'Avino, Vittoria; Liuzzi, Raffaele; Conson, Manuel; Farace, Paolo; Palma, Giuseppe; Schwarz, Marco; Cella, Laura; Pacelli, Roberto

    2017-05-01

    Proton beam therapy represents a promising modality for left-side breast cancer (BC) treatment, but concerns have been raised about skin toxicity and poor cosmesis. The aim of this study is to apply skin normal tissue complication probability (NTCP) model for intensity modulated proton therapy (IMPT) optimization in left-side BC. Ten left-side BC patients undergoing photon irradiation after breast-conserving surgery were randomly selected from our clinical database. Intensity modulated photon (IMRT) and IMPT plans were calculated with iso-tumor-coverage criteria and according to RTOG 1005 guidelines. Proton plans were computed with and without skin optimization. Published NTCP models were employed to estimate the risk of different toxicity endpoints for skin, lung, heart and its substructures. Acute skin NTCP evaluation suggests a lower toxicity level with IMPT compared to IMRT when the skin is included in proton optimization strategy (0.1% versus 1.7%, p < 0.001). Dosimetric results show that, with the same level of tumor coverage, IMPT attains significant heart and lung dose sparing compared with IMRT. By NTCP model-based analysis, an overall reduction in the cardiopulmonary toxicity risk prediction can be observed for all IMPT compared to IMRT plans: the relative risk reduction from protons varies between 0.1 and 0.7 depending on the considered toxicity endpoint. Our analysis suggests that IMPT might be safely applied without increasing the risk of severe acute radiation induced skin toxicity. The quantitative risk estimates also support the potential clinical benefits of IMPT for left-side BC irradiation due to lower risk of cardiac and pulmonary morbidity. The applied approach might be relevant on the long term for the setup of cost-effectiveness evaluation strategies based on NTCP predictions.

  4. Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari-Dizaji, M.; Sharafi, A. A.; Larijani, B.; Mokhlesian, N.; Hasanzadeh, H. [Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2008-04-15

    Objective : The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. Materials and Methods : An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. Result : There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 {mu}Gy and 1.81 Gy, respectively. Also, the scan center dose in the women was 5.70 Gy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. Conclusion : We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry.

  5. Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

    International Nuclear Information System (INIS)

    Mokhtari-Dizaji, M.; Sharafi, A. A.; Larijani, B.; Mokhlesian, N.; Hasanzadeh, H.

    2008-01-01

    Objective : The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. Materials and Methods : An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. Result : There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 μGy and 1.81 Gy, respectively. Also, the scan center dose in the women was 5.70 Gy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. Conclusion : We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry

  6. The estimation of effective doses using measurement of several relevant physical parameters from radon exposures

    International Nuclear Information System (INIS)

    Ridzikova, A; Fronka, A.; Maly, B.; Moucka, L.

    2003-01-01

    In the present investigation, we will be study the dose relevant factors from continual monitoring in real homes into account getting more accurate estimation of 222 Rn the effective dose. The dose relevant parameters include the radon concentration, the equilibrium factor (f), the fraction (fp) of unattached radon decay products and real time occupancy people in home. The result of the measurement are the time courses of radon concentration that are based on estimation effective doses together with assessment of the real time occupancy people indoor. We found out by analysis that year effective dose is lower than effective dose estimated by ICRP recommendation from the integral measurement that included only average radon concentration. Our analysis of estimation effective doses using measurement of several physical parameters was made only in one case and for the better specification is important to measure in different real occupancy houses. (authors)

  7. Estimation of doses to patients with chronic radiation sickness from external occupational exposure

    International Nuclear Information System (INIS)

    Jia Delin; Dai Guangfu

    1991-01-01

    The doses to patients with chronic radiation sickness who had engaged in diagnostic radiology have been estimated according to the radiation work load, type and capacity of X-ray equipment, protection conditions, data of nationwide survey on doses to X-ray workers in China, or the data of dose monitoring in working places. Based on the activities of radium sources, time taken up in performing radium therapy, distance to radium sources and radiation work load, the doses to patients who had engaged in radium therapy have been estimated. The results of estimated average doses for 29 cases of chronic radiation sickness are given. Their average red marrow dose, trunk dose and effective dose equivalent are 1.3 Gy, 1.2 Gy and 1.6 Sv, respectively

  8. Radiation doses measured by TLD (thermoluminescent dosimeter) in x-ray examination, especially on the skin area beneath of which female gonads situate

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, S; Hiraki, M; Murakami, S; Nishikawa, N; Yagi, T [Nissei Hospital, Osaka (Japan)

    1977-03-01

    By means of TLD, we measured the radiation doses to the skin in the central area of the field of radiation and doses scattered outside of the radiation field, utilizing a phantom to define a suitable radiation field. Clinically, when radiography of the gall bladder and the chest was done, we measured both the radiation doses of the central skin area where radiation was done and the skin above the area of the female gonads. In radiography of the chest, the radiation doses to the skin area above the female gonads situate was under 0.1 mR. When female gonads are less than 15 cm from the margin of the radiation field of the radiation dose can be decreased by 30% if gum sheets containing lead are used to cover the skin area outside the radiation field.

  9. Evaluation of the robustness of estimating five components from a skin spectral image

    Science.gov (United States)

    Akaho, Rina; Hirose, Misa; Tsumura, Norimichi

    2018-04-01

    We evaluated the robustness of a method used to estimate five components (i.e., melanin, oxy-hemoglobin, deoxy-hemoglobin, shading, and surface reflectance) from the spectral reflectance of skin at five wavelengths against noise and a change in epidermis thickness. We also estimated the five components from recorded images of age spots and circles under the eyes using the method. We found that noise in the image must be no more 0.1% to accurately estimate the five components and that the thickness of the epidermis affects the estimation. We acquired the distribution of major causes for age spots and circles under the eyes by applying the method to recorded spectral images.

  10. Acceleration of skin wound healing by low-dose indirect ionizing radiation in male rats.

    Science.gov (United States)

    Jabbari, Nasrollah; Farjah, Gholam Hossein; Ghadimi, Behnam; Zanjani, Hajar; Heshmatian, Behnam

    2017-08-01

    A recent hypothesis has revealed that low-dose irradiation (LDI) with ionizing radiation might have a promoting effect on fracture healing. The aim of this study was to investigate the influence of direct (electron beam) and indirect (gamma-ray) low-dose ionizing irradiations on the wound healing process in male rats. In 72 male rats, a full-thickness wound was incised. The animals were randomly assigned to three groups, each with 24 rats. The first two groups were named IG-I and IG-II and respectively exposed to electron and gamma-radiations (75 cGy) immediately after the surgical procedure. The third group was considered as the control (CG) and remained untreated. Skin biopsies from the subgroups were collected on days 3, 7, 15, and 21 after the operation and evaluated using histological and biomechanical methods. Data were analyzed by one-way ANOVA, followed by Tukey's post hoc test using SPSS 20 software. Histological studies of tissues showed that the mean number of fibroblasts, macrophages, blood vessel sections, and neutrophils on the third and seventh days after the surgery in the gamma-treated group was higher than that in both other groups. In contrast, on day 21, the mean number of mentioned cells in the gamma-treated group was lower than in the other two groups. In addition, the mean maximum stress value was significantly greater in the gamma-treated group. Results of this study showed that gamma-ray irradiation is effective in the acceleration of wound healing. Copyright © 2017. Published by Elsevier Taiwan.

  11. Acceleration of skin wound healing by low-dose indirect ionizing radiation in male rats

    Directory of Open Access Journals (Sweden)

    Nasrollah Jabbari

    2017-08-01

    Full Text Available A recent hypothesis has revealed that low-dose irradiation (LDI with ionizing radiation might have a promoting effect on fracture healing. The aim of this study was to investigate the influence of direct (electron beam and indirect (gamma-ray low-dose ionizing irradiations on the wound healing process in male rats. In 72 male rats, a full-thickness wound was incised. The animals were randomly assigned to three groups, each with 24 rats. The first two groups were named IG–I and IG–II and respectively exposed to electron and gamma-radiations (75 cGy immediately after the surgical procedure. The third group was considered as the control (CG and remained untreated. Skin biopsies from the subgroups were collected on days 3, 7, 15, and 21 after the operation and evaluated using histological and biomechanical methods. Data were analyzed by one-way ANOVA, followed by Tukey's post hoc test using SPSS 20 software. Histological studies of tissues showed that the mean number of fibroblasts, macrophages, blood vessel sections, and neutrophils on the third and seventh days after the surgery in the gamma-treated group was higher than that in both other groups. In contrast, on day 21, the mean number of mentioned cells in the gamma-treated group was lower than in the other two groups. In addition, the mean maximum stress value was significantly greater in the gamma-treated group. Results of this study showed that gamma-ray irradiation is effective in the acceleration of wound healing.

  12. Use of an electron reflector to improve dose uniformity at the vertex during total skin electron therapy

    International Nuclear Information System (INIS)

    Peters, V.G.

    2000-01-01

    Purpose: The vertex of the scalp is always tangentially irradiated during total skin electron therapy (TSET). This study was conducted to determine the dose distribution at the vertex for a commonly used irradiation technique and to evaluate the use of an electron reflector, positioned above the head, as a means of improving the dose uniformity. Methods and Materials: Phantoms, simulating the head of a patient, were irradiated using our standard procedure for TSET. The technique is a six-field irradiation using dual angled electron beams at a treatment distance of 3.6 meters. Vertex dosimetry was performed using ionization methods and film. Measurements were made for an unmodified 6 MeV electron beam and for a 4 MeV beam obtained by placing an acrylic scattering plate in the beam line. Studies were performed to examine the effect of electron scattering on vertex dose when a lead reflector, 50 x 50 cm in area, was positioned above the phantom. Results: The surface dose at the vertex, in the absence of the reflector, was found to be less than 40% of the prescribed skin dose. Use of the lead reflector increased this value to 73% for the 6 MeV beam and 99% for the degraded 4 MeV beam. Significant improvements in depth dose were also observed. The dose enhancement is not strongly dependent on reflector distance or angulation since the reflector acts as a large source of broadly scattered electrons. Conclusion: The vertex may be significantly underdosed using standard techniques for total skin electron therapy. Use of an electron reflector improves the dose uniformity at the vertex and may reduce or eliminate the need for supplemental irradiation

  13. SU-E-T-86: A Systematic Method for GammaKnife SRS Fetal Dose Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Geneser, S; Paulsson, A; Sneed, P; Braunstein, S; Ma, L [UCSF Comprehensive Cancer Center, San Francisco, CA (United States)

    2015-06-15

    Purpose: Estimating fetal dose is critical to the decision-making process when radiation treatment is indicated during pregnancy. Fetal doses less than 5cGy confer no measurable non-cancer developmental risks but can produce a threefold increase in developing childhood cancer. In this study, we estimate fetal dose for a patient receiving Gamma Knife stereotactic radiosurgery (GKSRS) treatment and develop a method to estimate dose directly from plan details. Methods: A patient underwent GKSRS on a Perfexion unit for eight brain metastases (two infratentorial and one brainstem). Dose measurements were performed using a CC13, head phantom, and solid water. Superficial doses to the thyroid, sternum, and pelvis were measured using MOSFETs during treatment. Because the fetal dose was too low to accurately measure, we obtained measurements proximally to the isocenter, fitted to an exponential function, and extrapolated dose to the fundus of the uterus, uterine midpoint, and pubic synthesis for both the preliminary and delivered plans. Results: The R-squared fit for the delivered doses was 0.995. The estimated fetal doses for the 72 minute preliminary and 138 minute delivered plans range from 0.0014 to 0.028cGy and 0.07 to 0.38cGy, respectively. MOSFET readings during treatment were just above background for the thyroid and negligible for all inferior positions. The method for estimating fetal dose from plan shot information was within 0.2cGy of the measured values at 14cm cranial to the fetal location. Conclusion: Estimated fetal doses for both the preliminary and delivered plan were well below the 5cGy recommended limit. Due to Pefexion shielding, internal dose is primarily governed by attenuation and drops off exponentially. This is the first work that reports fetal dose for a GK Perfexion unit. Although multiple lesions were treated and the duration of treatment was long, the estimated fetal dose remained very low.

  14. SU-E-T-86: A Systematic Method for GammaKnife SRS Fetal Dose Estimation

    International Nuclear Information System (INIS)

    Geneser, S; Paulsson, A; Sneed, P; Braunstein, S; Ma, L

    2015-01-01

    Purpose: Estimating fetal dose is critical to the decision-making process when radiation treatment is indicated during pregnancy. Fetal doses less than 5cGy confer no measurable non-cancer developmental risks but can produce a threefold increase in developing childhood cancer. In this study, we estimate fetal dose for a patient receiving Gamma Knife stereotactic radiosurgery (GKSRS) treatment and develop a method to estimate dose directly from plan details. Methods: A patient underwent GKSRS on a Perfexion unit for eight brain metastases (two infratentorial and one brainstem). Dose measurements were performed using a CC13, head phantom, and solid water. Superficial doses to the thyroid, sternum, and pelvis were measured using MOSFETs during treatment. Because the fetal dose was too low to accurately measure, we obtained measurements proximally to the isocenter, fitted to an exponential function, and extrapolated dose to the fundus of the uterus, uterine midpoint, and pubic synthesis for both the preliminary and delivered plans. Results: The R-squared fit for the delivered doses was 0.995. The estimated fetal doses for the 72 minute preliminary and 138 minute delivered plans range from 0.0014 to 0.028cGy and 0.07 to 0.38cGy, respectively. MOSFET readings during treatment were just above background for the thyroid and negligible for all inferior positions. The method for estimating fetal dose from plan shot information was within 0.2cGy of the measured values at 14cm cranial to the fetal location. Conclusion: Estimated fetal doses for both the preliminary and delivered plan were well below the 5cGy recommended limit. Due to Pefexion shielding, internal dose is primarily governed by attenuation and drops off exponentially. This is the first work that reports fetal dose for a GK Perfexion unit. Although multiple lesions were treated and the duration of treatment was long, the estimated fetal dose remained very low

  15. Influence trend of temperature distribution in skin tissue generated by different exposure dose pulse laser

    Science.gov (United States)

    Shan, Ning; Wang, Zhijing; Liu, Xia

    2014-11-01

    Laser is widely applied in military and medicine fields because of its excellent capability. In order to effectively defend excess damage by laser, the thermal processing theory of skin tissue generated by laser should be carried out. The heating rate and thermal damage area should be studied. The mathematics model of bio-tissue heat transfer that is irradiated by laser is analyzed. And boundary conditions of bio-tissue are discussed. Three layer FEM grid model of bio-tissue is established. The temperature rising inducing by pulse laser in the tissue is modeled numerically by adopting ANSYS software. The changing trend of temperature in the tissue is imitated and studied under the conditions of different exposure dose pulse laser. The results show that temperature rising in the tissue depends on the parameters of pulse laser largely. In the same conditions, the pulse width of laser is smaller and its instant power is higher. And temperature rising effect in the tissue is very clear. On the contrary, temperature rising effect in the tissue is lower. The cooling time inducing by temperature rising effect in the tissue is longer along with pulse separation of laser is bigger. And the temperature difference is bigger in the pulse period.

  16. Estimation of lens dose of radioactive isotopes using ED3

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ha Jin; Ju, Yong Jin; Jang, Han; Kang, Kyeong Won; Chung, Woon Kwan [Chosun University, Gwangju (Korea, Republic of); Dong, Kyung Rae [Gwangju Health University, Gwangju (Korea, Republic of); Choi, Eun Jin; Kwak, Jong Gil [Dongshin University Graduate School, Naju (Korea, Republic of); Ryu, Jae Kwang [Asan Medical Center, Seoul (Korea, Republic of)

    2017-03-15

    It is suggested that the dose limit recommended in the Enforcement Decree of Korea's Nuclear Safety Act should not exceed 150 mSv per year for radiation workers. Recently, however, ICRP 118 report has suggested that the threshold dose of the lens should be reduced to 0.2⁓0.5 Gy and the mean dose should not exceed 50 mSv per year for an average of 20 mSv over 5 years. Based on these contents, '1'2'3I, '9'9mTc, and '1'8F-FDG, which are radioisotope drugs that are used directly by radiation workers in the nuclear medicine department in Korea are expected to receive a large dose of radiation in the lens in distribution and injection jobs to administer them to patients. The ED3 Active Extremity Dosimeter was used to measure the dose of the lens in the nuclear medicine and radiation workers and how much of the dose was received per 1 mCi.

  17. The local skin dose conversion coefficients of electrons, protons and alpha particles calculated using the Geant4 code.

    Science.gov (United States)

    Zhang, Bintuan; Dang, Bingrong; Wang, Zhuanzi; Wei, Wei; Li, Wenjian

    2013-10-01

    The skin tissue-equivalent slab reported in the International Commission on Radiological Protection (ICRP) Publication 116 to calculate the localised skin dose conversion coefficients (LSDCCs) was adopted into the Monte Carlo transport code Geant4. The Geant4 code was then utilised for computation of LSDCCs due to a circular parallel beam of monoenergetic electrons, protons and alpha particles electrons and alpha particles are found to be in good agreement with the results using the MCNPX code of ICRP 116 data. The present work thus validates the LSDCC values for both electrons and alpha particles using the Geant4 code.

  18. Implication of new CEC recommendations for individual monitoring for external radiation doses to the skin and the extremities

    DEFF Research Database (Denmark)

    Christensen, P.; Julius, H.W.; Marshall, T.O.

    1991-01-01

    A drafting group consisting of the above authors has assisted the CEC in revising the CEC document Technical Recommendations for Monitoring the Exposure to Individuals to External Radiation, EUR 5287, published in 1975. The paper highlights sections of the revised version relating particularly...... to irradiation of the skin and the extremities and focusses on problems connected to exposure to weakly penetrating radiations. Concepts of individual monitoring for external radiation exposures to the skin of the whole body and to the extremities are discussed and guidance is given as regards dose quantities...

  19. Electron dose-rate conversion factors for external exposure of the skin from uniformly deposited activity on the body surface

    International Nuclear Information System (INIS)

    Kocher, D.C.; Eckerman, K.F.

    1987-01-01

    Dose-rate conversion factors have been calculated for external exposure of the skin from electrons emitted by sources that are deposited uniformly on the body surface. The dose-rate factors are obtained from electron scaled point kernels developed by Berger. The dose-rate factors are calculated at depths of 4, 8, and 40 mg cm-2 below the body surface as recommended by Whitton, and at a depth of 7 mg cm-2 as recommended in ICRP Publication 26 (ICRP77). The dependence of the dose-rate factors at selected depths on the energy of the emitted electrons is displayed. The dose-rate factors for selected radionuclides of potential importance in radiological assessments are tabulated

  20. Convolution-based estimation of organ dose in tube current modulated CT

    Science.gov (United States)

    Tian, Xiaoyu; Segars, W. Paul; Dixon, Robert L.; Samei, Ehsan

    2016-05-01

    Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460-7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18-70 years, weight range: 60-180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ({{h}\\text{Organ}} ) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} with the organ dose coefficients ({{h}\\text{Organ}} ). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled. The

  1. Dose enhancement in the neighborhood of foreign bodies of the skin due to electron irradiation. A Monte-Carlo study using MCNP

    Energy Technology Data Exchange (ETDEWEB)

    Heide, Bernd [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (DE). Inst. of Radiation Research (ISF)

    2011-07-01

    Foreign bodies penetrate into the skin in the region of the hand very frequently. If they are amicrobic, they can get stuck in the skin and do no harm to the body in normal case. However, when handling with a radioactive material, like an Sr-90/Y-90 syringe for example, a stuck foreign body in a finger can lead to an enhanced absorbed dose in the neighbourhood of a few hundredths of millimetre of a foreign body, which just is in magnitude of a body cell. In the following, we shall investigate the dose enhancement effect of graphite, lead, and gold when embedded in soft tissue and irradiated with electrons. This case study focusses on the region close to the piece of metal (foreign body) without consideration for the depth in which the foreign body is located. It holds some other idealised assumptions (concerning vacuum, shape and size of foreign bodies, tissue composition, and direction of the radiation field) but still is near to real situations. Among others, this case study served to estimate the dose enhancement in the neighbourhood of a pike of lead located at the right forefinger of a member of our Institute of Radiation Research after an Sr-90/Y-90 irradiation. (orig.)

  2. Total Skin Electron Beam Therapy in the Treatment of Mycosis Fungoides: A Review of Conventional and Low-Dose Regimens.

    Science.gov (United States)

    Chowdhary, Mudit; Chhabra, Arpit M; Kharod, Shivam; Marwaha, Gaurav

    2016-12-01

    Mycosis fungoides (MF) is the most prevalent subtype of cutaneous T-cell lymphoma, which is characterized by the proliferation of CD4 + T cells. While often an indolent disease, most patients eventually develop progression from isolated patches to tumors and finally nodal or visceral involvement. Treatment choice is largely based on disease burden, though prognostic factors such as disease stage, patient age, and extracutaneous involvement must be taken into consideration. Radiotherapy represents one of the most effective therapeutic modalities in the treatment of MF. Lymphocytes are exquisitely radiosensitive, and excellent responses are observed even with low doses of radiation. Total skin electron beam therapy (TSEBT) is a special technique that allows for the homogenous irradiation of the entire skin. There are well-documented radiation dose-response relationships for achieving a complete response. As such, TSEBT doses ≥ 30 Gy comprise the current standard of care. Although highly effective, most patients experience recurrent disease even after conventional-dose (≥ 30 Gy) TSEBT. In addition, toxicity is cumulatively dose dependent, and there is reluctance to administer multiple courses of conventional-dose TSEBT. Consequently, there has been renewed interest in determining the utility of TSEBT at lower total (≤ 30 Gy) doses. Advantages of low-total-dose (with standard dose per fraction) TSEBT include a shortened treatment course, the potential to minimize the risk of adverse events, and the opportunity to allow for retreatment in cases of disease recurrence. This comprehensive review compares the impact of different TSEBT dosing schemes on clinical outcomes of MF. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Estimation of the transit dose component in high dose rate brachytherapy

    International Nuclear Information System (INIS)

    Garcia Romero, A.; Millan Cebrian, E.; Lozano Flores, F.J.; Lope Lope, R.; Canellas Anoz, M.

    2001-01-01

    Current high dose rate brachytherapy (HDR) treatment planning systems usually calculate dose only from source stopping positions (stationary component), but fails to account for the administered dose when the source is moving (dynamic component or transit dose). Numerical values of this transit dose depends upon the source velocity, implant geometry, source activity and prescribed dose. In some HDR treatments using particular geometry the transit dose cannot be ignored because it increases the dose at the prescriptions points and also could increase potential late tissue complications as predicted by the linear quadratic model. International protocols recommend to verify this parameter. The aim of this paper has been to establish a procedure for the transit dose calculation for the Gammamed 12i equipment at the RT Department in the Clinical University Hospital (Zaragoza-Spain). A numeric algorithm was implemented based on a dynamic point approximation for the moving HDR source and the calculated results for the entrance-exit transit dose was compared with TLD measurements made in some discrete points. (author) [es

  4. ESTIMATION OF THE CONVERSION COEFFICIENTS FROM DOSE-AREA PRODUCT TO EFFECTIVE DOSE FOR BARIUM MEAL EXAMINATIONS FOR ADULT PATIENTS

    Directory of Open Access Journals (Sweden)

    A. V. Vodovatov

    2018-01-01

    Full Text Available Fluoroscopic examinations of the upper gastro-intestinal tract and, especially, barium meal examinations, are commonly performed in a majority of hospitals. These examinations are associated both with substantial individual patient doses and contribution to the collective dose from medical exposure. Effective dose estimation for this type of examinations is complicated due to: 1 the necessity to simulate the moving X-ray irradiation field; 2 differences in study structure for the individual patients; 3 subjectivity of the operators; and 4 differences in the X-ray equipment. The aim of the current study was to estimate conversion coefficients from dose-area product to effective dose for barium meal examinations for the over couch and under couch exposure conditions. The study was based on data collected in the X-ray unit of the surgical department of the St-Petersburg Mariinsky hospital. A model of patient exposure during barium meal examination was developed based on the collected data on fluoroscopy protocols and adult patient irradiation geometry. Conversion coefficients were calculated using PCXMC 2.0 software. Complete examinations were converted into a set of typical fluoroscopy phases and X-ray images, specified by the examined anatomical region and the projection of patient exposure. Conversion coefficients from dose-area product to effective dose were calculated for each phase of the examination and for the complete examination. The resulting values of the conversion coefficients are comparable with published data. Variations in the absolute values of the conversion coefficients can be explained by differences in clinical protocols, models for the estimation of the effective dose and parameters of barium meal examinations. The proposed approach for estimation of effective dose considers such important features of fluoroscopic examinations as: 1 non-uniform structure of examination, 2 significant movement of the X-ray tube within a single

  5. Estimated neutron dose to embryo and foetus during commercial flight

    International Nuclear Information System (INIS)

    Chen, J.; Lewis, B. J.; Bennett, L. G. I.; Green, A. R.; Tracy, B. L.

    2005-01-01

    A study has been carried out to assess the radiation exposure from cosmic-ray neutrons to the embryo and foetus of pregnant aircrew and air travellers in consideration of the radiation exposure from cosmic-ray neutrons to the embryo and foetus. A Monte Carlo analysis was performed to determine the equivalent dose from neutrons to the brain and body of an embryo at 8 weeks and to the foetus at the 3, 6 and 9 month periods. Neutron fluence-to-absorbed dose conversion coefficients for the foetal brain and for the entire foetal body (isotropic irradiation geometry) have been determined at the four developmental stages. The equivalent dose rate to the foetus during commercial flights has been further evaluated considering the fluence-to-absorbed dose conversion coefficients, a neutron spectrum measured at an altitude of 11.3 km and an ICRP-92 radiation-weighting factor for neutrons. This study indicates that the foetus can exceed the annual dose limit of 1 mSv for the general public after, for example, 15 round trips on commercial trans-Atlantic flights. (authors)

  6. NIRS external dose estimation system for Fukushima residents after the Fukushima Dai-ichi NPP accident

    Science.gov (United States)

    Akahane, Keiichi; Yonai, Shunsuke; Fukuda, Shigekazu; Miyahara, Nobuyuki; Yasuda, Hiroshi; Iwaoka, Kazuki; Matsumoto, Masaki; Fukumura, Akifumi; Akashi, Makoto

    2013-04-01

    The great east Japan earthquake and subsequent tsunamis caused Fukushima Dai-ichi Nuclear Power Plant (NPP) accident. National Institute of Radiological Sciences (NIRS) developed the external dose estimation system for Fukushima residents. The system is being used in the Fukushima health management survey. The doses can be obtained by superimposing the behavior data of the residents on the dose rate maps. For grasping the doses, 18 evacuation patterns of the residents were assumed by considering the actual evacuation information before using the survey data. The doses of the residents from the deliberate evacuation area were relatively higher than those from the area within 20 km radius. The estimated doses varied from around 1 to 6 mSv for the residents evacuated from the representative places in the deliberate evacuation area. The maximum dose in 18 evacuation patterns was estimated to be 19 mSv.

  7. Estimation of patient dose in mammography screening examinations

    International Nuclear Information System (INIS)

    Suzuki, S.; Fujii, S.; Orito, T.; Asada, Y.; Koga, S.; Horita, K.; Kido, C.

    1996-01-01

    Mammography is one of the most effective examinations for detecting breast carcinoma. Although the dose is usually much higher than that in other types of X-ray examination, that is accepted by the patient because for fears of suffering cancer. Benefit of relatively high doses derived from mammographic examinations is considered to well exceed the risk of cancer induction by radiation exposure. The purpose of this study is to investigate patient dose of mammography in Japan by questionnaire sent to 531 institutions selected from whole Japan and direct measurements carried out in 28 hospitals in Aichi Prefecture. The user's guide in mammography published by NCRP and Quality Assurance Program of American College of Radiology were used to assess the exposure and image quality of mammogram. (author)

  8. Estimation dose of secondary neutrons in proton therapy

    International Nuclear Information System (INIS)

    Urban, T.

    2014-01-01

    Most of proton therapy centers for cancer treatment are still based on the passive scattering, in some of them there is system of the active scanning installed as well. The aim of this study is to compare secondary neutron doses in and around target volumes in proton therapy for both treatment techniques and for different energies and profile of incident proton beam. The proton induced neutrons have been simulated in the very simple geometry of tissue equivalent phantom (imitate the patient) and scattering and scanning nozzle, respectively. In simulations of the scattering nozzle, different types of scattering filters and brass collimators have been used as well. 3D map of neutron doses in and around the chosen/potential target volume in the phantom/patient have been evaluated and compared in the context of the dose deposited in the target volume. Finally, the simulation results have been compared with published data. (author)

  9. Irradiation in helical scanner: doses estimation, parameters choice

    International Nuclear Information System (INIS)

    Cordoliani, Y.S.; Boyer, B.; Jouan, E.; Beauvais, H.

    2001-01-01

    The new generation of helical scanners improves the diagnosis abilities and the service done to the patients. The rational use allows to give the patients a ratio benefit/risk far better than the almost medical examinations. It is particularly true for over sixty years old aged people, that have a null genetic risk and a practically null carcinogen risk; However, for young adults and children, it is necessary to banish any useless irradiation and limit exposure to the strict necessary for the diagnosis. It is necessary to develop a radiation protection culture, possible by the radiation doses index display and doses benchmarks knowledge. (N.C.)

  10. Treatment of skin carcinomas of the face by high-dose-rate brachytherapy and custom-made surface molds

    International Nuclear Information System (INIS)

    Guix, Benjamin; Finestres, Fernando; Tello, Jose-Ignacio; Palma, Cesar; Martinez, Antonio; Guix, Jose-Ramon; Guix, Ricardo

    2000-01-01

    Purpose: To analyze the results obtained in a prospective group of patients with basal or squamous cell skin carcinomas of the face treated by high-dose-rate (HDR) brachytherapy via custom-made surface molds. Methods and Materials: A total of 136 patients with basal or squamous cell carcinomas of the face were treated between March 1992 and March 1997 by surface molds and HDR brachytherapy with iridium-192. Nineteen patients were treated with standard Brock applicators and 117 patients with custom-made polymethyl methacrylate applicators, built over a plaster mold obtained of the patient's face. Minimum dose administered to the tumor was 6000 to 6500 cGy in 33 to 36 fractions at 180 cGy/fraction in lesions of up to 4 cm. Lesions greater than 4 cm were boosted up to 7500-8000 cGy after a 3-week pause. Results: With the custom-made surface molds, the dose distribution was uniform in the surface of the skin and at 5 mm depth in the whole area of the applicator. Differences between the areas of maximum and minimum dose at this depth never reached values higher than 5% of the prescribed dose. At the edges of the custom-made molds dose gradient was sharp, with the detected dose at 5 mm from the applicator being negligible. All the patients were complete responders. There were 3 local recurrences, 1/73 patients treated for primary tumor and 2/63 patients treated for recurrent tumor. Actuarial local control at 5 years for all patients was 98%, for those patients with primary tumors 99%, and for recurrent patients 87%. The treatment tolerance was excellent in all cases. No severe, early, or late, complications were detected. Conclusions: Radiotherapy is a highly effective treatment of skin carcinomas of the face. Custom-made molds, to be used in conjunction with HDR brachytherapy equipment, make possible a uniform dose distribution, with a sharp dose gradient in the limits of applicators. Custom-made surface molds are easy and safe to use, and they fit very accurately for

  11. Dose estimation for the eye lens dealing with radioactive wastes

    International Nuclear Information System (INIS)

    Krause, A.; Lorenz, B.; Wuertemberger, M.

    2013-01-01

    A significant reduction of the dose limit for the lens of the eye is currently discussed in international committees. The ICRP had recommended a reduction from 150 mSv to 20 mSv, the IAEA-BSS have already adopted this value and the Euratom-BSS propose this too. In the practice of radiation protection the compliance with the limit for the lens of the eye has played a minor role so far. This was in practice assured by the compliance with the limit for the effective dose. With a possible stipulation of a much lower value in the Radiation Protection Ordinance (StrlSchV), the question of compliance arises again. When handling radioactive waste where often gamma radiation is dominant it may happen that the (unshielded) eye region is much more exposed as the location of the (shielded) personal dosimeter. A theoretical study of typical GNS-workplaces in radioactive waste management has shown that up to a factor of 4 higher exposures may occur. A generic assessment under very conservative assumptions that was done first did not allow for the conclusion that the compliance of the new dose limit for the lens of the eye is given by complying with the limit for the effective dose. To get a more reliable basis the exposure situation will now be investigated by measurements that are carried out with specific TLDs provided by the MPA Dortmund. (orig.)

  12. Dose estimative in operators during petroleum wells logging with nuclear wireless probes through computer modelling

    International Nuclear Information System (INIS)

    Souza, Edmilson Monteiro de; Silva, Ademir Xavier da; Lopes, Ricardo T.; Correa, Samanda Cristine Arruda; Rocha, Paula L.F.

    2011-01-01

    This paper evaluates the absorbed dose and the effective dose on operators during the petroleum well logging with nuclear wireless that uses gamma radiation sources. To obtain the data, a typical scenery of a logging procedure will be simulated with MCNPX Monte Carlo code. The simulated logging probe was the Density Gamma Probe - TRISOND produced by Robertson Geolloging. The absorbed dose values were estimated through the anthropomorphic simulator in male voxel MAX. The effective dose values were obtained using the ICRP 103

  13. Development of a fibre-optic dosemeter to measure the skin dose and percentage depth dose in the build-up region of therapeutic photon beams

    International Nuclear Information System (INIS)

    Kim, K. A.; Yoo, W. J.; Jang, K. W.; Moon, J.; Han, K. T.; Jeon, D.; Park, J. Y.; Cha, E. J.; Lee, B.

    2013-01-01

    In this study, a fibre-optic dosemeter (FOD) using an organic scintillator with a diameter of 0.5 mm for photon-beam therapy dosimetry was fabricated. The fabricated dosemeter has many advantages, including water equivalence, high spatial resolution, remote sensing and real-time measurement. The scintillating light generated from an organic-dosemeter probe embedded in a solid-water stack phantom is guided to a photomultiplier tube and an electrometer via 20 m of plastic optical fibre. Using this FOD, the skin dose and the percentage depth dose in the build-up region according to the depths of a solid-water stack phantom are measured with 6- and 15-MV photon-beam energies with field sizes of 10310 and 20320 cm 2 , respectively. The results are compared with those measured using conventional dosimetry films. It is expected that the proposed FOD can be effectively used in radiotherapy dosimetry for accurate measurement of the skin dose and the depth dose distribution in the build-up region due to its high spatial resolution. (authors)

  14. Construction of boundary-surface-based Chinese female astronaut computational phantom and proton dose estimation

    Science.gov (United States)

    Sun, Wenjuan; JIA, Xianghong; XIE, Tianwu; XU, Feng; LIU, Qian

    2013-01-01

    With the rapid development of China's space industry, the importance of radiation protection is increasingly prominent. To provide relevant dose data, we first developed the Visible Chinese Human adult Female (VCH-F) phantom, and performed further modifications to generate the VCH-F Astronaut (VCH-FA) phantom, incorporating statistical body characteristics data from the first batch of Chinese female astronauts as well as reference organ mass data from the International Commission on Radiological Protection (ICRP; both within 1% relative error). Based on cryosection images, the original phantom was constructed via Non-Uniform Rational B-Spline (NURBS) boundary surfaces to strengthen the deformability for fitting the body parameters of Chinese female astronauts. The VCH-FA phantom was voxelized at a resolution of 2 × 2 × 4 mm3for radioactive particle transport simulations from isotropic protons with energies of 5000–10 000 MeV in Monte Carlo N-Particle eXtended (MCNPX) code. To investigate discrepancies caused by anatomical variations and other factors, the obtained doses were compared with corresponding values from other phantoms and sex-averaged doses. Dose differences were observed among phantom calculation results, especially for effective dose with low-energy protons. Local skin thickness shifts the breast dose curve toward high energy, but has little impact on inner organs. Under a shielding layer, organ dose reduction is greater for skin than for other organs. The calculated skin dose per day closely approximates measurement data obtained in low-Earth orbit (LEO). PMID:23135158

  15. Uncertainties in effective dose estimates of adult CT head scans: The effect of head size

    International Nuclear Information System (INIS)

    Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E.

    2009-01-01

    Purpose: This study is an extension of a previous study where the uncertainties in effective dose estimates from adult CT head scans were calculated using four CT effective dose estimation methods, three of which were computer programs (CT-EXPO, CTDOSIMETRY, and IMPACTDOSE) and one that involved the dose length product (DLP). However, that study did not include the uncertainty contribution due to variations in head sizes. Methods: The uncertainties due to head size variations were estimated by first using the computer program data to calculate doses to small and large heads. These doses were then compared with doses calculated for the phantom heads used by the computer programs. An uncertainty was then assigned based on the difference between the small and large head doses and the doses of the phantom heads. Results: The uncertainties due to head size variations alone were found to be between 4% and 26% depending on the method used and the patient gender. When these uncertainties were included with the results of the previous study, the overall uncertainties in effective dose estimates (stated at the 95% confidence interval) were 20%-31% (CT-EXPO), 15%-30% (CTDOSIMETRY), 20%-36% (IMPACTDOSE), and 31%-40% (DLP). Conclusions: For the computer programs, the lower overall uncertainties were still achieved when measured values of CT dose index were used rather than tabulated values. For DLP dose estimates, head size variations made the largest (for males) and second largest (for females) contributions to effective dose uncertainty. An improvement in the uncertainty of the DLP method dose estimates will be achieved if head size variation can be taken into account.

  16. Uncertainties in effective dose estimates of adult CT head scans: The effect of head size

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E. [Department of Medical Physics, Royal Adelaide Hospital, Adelaide, South Australia 5000 (Australia) and School of Electrical and Information Engineering (Applied Physics), University of South Australia, Mawson Lakes, South Australia 5095 (Australia); Division of Medical Imaging, Women' s and Children' s Hospital, North Adelaide, South Australia 5006 (Australia) and School of Electrical and Information Engineering (Applied Physics), University of South Australia, Mawson Lakes, South Australia 5095 (Australia); School of Electrical and Information Engineering (Applied Physics), University of South Australia, Mawson Lakes, South Australia 5095 (Australia)

    2009-09-15

    Purpose: This study is an extension of a previous study where the uncertainties in effective dose estimates from adult CT head scans were calculated using four CT effective dose estimation methods, three of which were computer programs (CT-EXPO, CTDOSIMETRY, and IMPACTDOSE) and one that involved the dose length product (DLP). However, that study did not include the uncertainty contribution due to variations in head sizes. Methods: The uncertainties due to head size variations were estimated by first using the computer program data to calculate doses to small and large heads. These doses were then compared with doses calculated for the phantom heads used by the computer programs. An uncertainty was then assigned based on the difference between the small and large head doses and the doses of the phantom heads. Results: The uncertainties due to head size variations alone were found to be between 4% and 26% depending on the method used and the patient gender. When these uncertainties were included with the results of the previous study, the overall uncertainties in effective dose estimates (stated at the 95% confidence interval) were 20%-31% (CT-EXPO), 15%-30% (CTDOSIMETRY), 20%-36% (IMPACTDOSE), and 31%-40% (DLP). Conclusions: For the computer programs, the lower overall uncertainties were still achieved when measured values of CT dose index were used rather than tabulated values. For DLP dose estimates, head size variations made the largest (for males) and second largest (for females) contributions to effective dose uncertainty. An improvement in the uncertainty of the DLP method dose estimates will be achieved if head size variation can be taken into account.

  17. Equine scintigraphy: assessment of the dose received by the personnel; Scintigraphie equine: estimation de la dose recue par le personnel

    Energy Technology Data Exchange (ETDEWEB)

    Clairand, I.; Bottollier, J.F.; Trompier, F. [Institut de Radioprotection et de Surete Nucleaire IRSN, 92 - Fontenay aux Roses (France)

    2003-03-01

    Following a request from the Permanent Secretary of the French Commission for Artificial Radioelements (CIREA) engaged to investigate a request for a licence related to a new scintigraphy unit dedicated to equidae, a dosimetric assessment concerning the personnel attending the examination was carried out. This scintigraphy unit depends on the Goustranville Centre for Imaging and Research on the Locomotive Diseases of Equidae (CIRALE) in the Calvados region. The dosimetric assessment was carried out for the different operators during the successive stages of the scintigraphic examination. Assuming 150 examinations per year, the annual equivalent dose to the fingers skin is 150 mSv maximum for the technologist and 2 mSv for the veterinary surgeon; the annual effective dose ranges from 0.15 to 0.45 mSv, depending on the operators. (authors)

  18. Measurement of patient skin absorbed dose in ablation of paroxysmal atrial fibrillation, and examination of treatment protocol

    International Nuclear Information System (INIS)

    Shohji, Tomokazu; Hiramatsu, Masaki; Hasome, Hideki

    2005-01-01

    The ablation for atrial fibrillation minute movement done in our hospital is 250 minutes or less, within an average time of 150 minutes during a fluoroscopic time of about 7 hours, with very large average inspection times numerical values. However, the skin-absorbed dose could be understood only from the numerical value of the area dosimeter. It was considered that the total dose that reached the threshold was sufficient, although radiation injury would not be reported from the ablation currently done at our hospital. Therefore, we aimed to examine the inspection protocol in this hospital, and to request the patient be given an inspection dose that was the average skin-absorbed dose by using the acryl board. The amount of a total dose for an inspection of 150 minutes of fluoroscopic time was about 2.7 Gy. Moreover, a value of 1.5 Gy was indicated in the hot spot as a result of repetition in some exposure fields. However, it was thought that the possibility of exceeding the threshold of 2 Gy depending on the inspection situation in the future and other factors was tolerable because these measurements were done so as not to overvalue it more than the necessary. (author)

  19. A study of the relationship between peak skin dose and cumulative air kerma in interventional neuroradiology and cardiology

    International Nuclear Information System (INIS)

    Neil, S; Padgham, C; Martin, C J

    2010-01-01

    A study of peak skin doses (PSDs) during neuroradiology and cardiology interventional procedures has been carried out using Gafchromic XR-RV2 film. Use of mosaics made from squares held in cling film has allowed doses to the head to be mapped successfully. The displayed cumulative air kerma (CAK) has been calibrated in terms of cumulative entrance surface dose (CESD) and results indicate that this can provide a reliable indicator of the PSD in neuroradiology. Results linking PSD to CESD for interventional cardiology were variable, but CAK is still considered to provide the best option for use as an indicator of potential radiation-induced effects. A CESD exceeding 3 Gy is considered a suitable action level for triggering follow-up of patients in neuroradiology and cardiology for possible skin effects. Application of dose action levels defined in this way would affect 8% of neurological embolisation procedures and 5% of cardiology ablation and multiple stent procedures at the hospitals where the investigations were carried out. A close relationship was observed between CESD and dose-area product (DAP) for particular types of procedure, and DAPs of 200-300 Gy cm 2 could be used as trigger levels where CAK readings were not available. The DAP value would depend on the mean field size and would need to be determined for each application.

  20. Monte Carlo simulation for the estimation of the glandular breast dose for a digital breast tomosynthesis system

    International Nuclear Information System (INIS)

    Rodrigues, Leonardo; Braz, Delson; Goncalves Magalhaes, Luis Alexandre

    2015-01-01

    Digital breast tomosynthesis (DBT) is a screening and diagnostic modality that acquires images of the breast at multiple angles during a short scan. The Selenia Dimensions (Hologic, Bedford, Mass) DBT system can perform both full-field digital mammography and DBT. The system acquires 15 projections over a 15 deg. angular range (from -7.5 deg. to +7.5 deg.). An important factor in determining the optimal imaging technique for breast tomosynthesis is the radiation dose. In breast imaging, the radiation dose of concern is that deposited in the glandular tissue of the breast because this is the tissue that has a risk of developing cancer. The concept of the normalised mean glandular dose (DgN) has been introduced as the metric for the dose in breast imaging. The DgN is difficult to measure. The Monte Carlo techniques offer an alternative method for a realistic estimation of the radiation dose. The purpose of this work was to use the Monte Carlo code MCNPX technique to generate monoenergetic glandular dose data for estimating the breast tissue dose in tomosynthesis for arbitrary spectra as well as to observe the deposited radiation dose by projection on the glandular portion of the breast in a Selenia Dimensions DBT system. A Monte Carlo simulation of the system was developed to compute the DgN in a craniocaudal view. Monoenergetic X-ray beams from 10 to 49 keV in 1-keV increments were used. The simulation utilised the assumption of a homogeneous breast composition and three compositions (0 % glandular, 50 % glandular and 100 % glandular). The glandular and adipose tissue compositions were specified according ICRU Report 44. A skin layer of 4 mm was assumed to encapsulate the breast on all surfaces. The breast size was varied using the chest wall-to-nipple distance (CND) and compressed breast thickness (t). In this work, the authors assumed a CND of 5 cm and the thicknesses ranged from 2 to 8 cm, in steps of 2 cm. The fractional energy absorption increases (up to 44

  1. Effects of exposure imprecision on estimation of the benchmark dose

    DEFF Research Database (Denmark)

    Budtz-Jørgensen, Esben; Keiding, Niels; Grandjean, Philippe

    2004-01-01

    In regression analysis failure to adjust for imprecision in the exposure variable is likely to lead to underestimation of the exposure effect. However, the consequences of exposure error for determination of safe doses of toxic substances have so far not received much attention. The benchmark...... approach is one of the most widely used methods for development of exposure limits. An important advantage of this approach is that it can be applied to observational data. However, in this type of data, exposure markers are seldom measured without error. It is shown that, if the exposure error is ignored......, then the benchmark approach produces results that are biased toward higher and less protective levels. It is therefore important to take exposure measurement error into account when calculating benchmark doses. Methods that allow this adjustment are described and illustrated in data from an epidemiological study...

  2. PTTL Dose Re-estimation Applied to Quality Control in TLD-100 Based Personal Dosimetry

    International Nuclear Information System (INIS)

    Muniz, J.L.; Correcher, V.; Delgado, A.

    1999-01-01

    A new method for quality control of dose performance in Personal Dosimetry using TLD-100 is presented. This method consists of the application of dose reassessment techniques based on phototransferred thermoluminescence (PTTL). Reassessment is achieved through a second TL readout of the dosemeters worn by the controlled workers, after a reproducible UV exposure. Recent refinements in the PTTL technique developed in our laboratory allow reassessing doses as low as 0.2 mSv, thus extending the reassessment capability to the entire dose range that must be monitored in personal dosimetry. After a one month exposure, even purely environmental doses can be reassessed. This method can be applied for either re-estimation of single doses or of the total dose accumulated after a number of exposures and dose measurements. Several tests to reconfirm low doses in normal working conditions for personal dosimetry have been performed. Each test consisted of several cycles of exposure and TL evaluations and a final PTTL re-estimation of the total accumulated dose in those cycles. The results obtained always showed very good agreement between the sum of the partial doses and the total reassessed dose. The simplicity of the method and the possibility of re-evaluating the doses assessed to the workers employing their own dosemeters are advantageous features to be considered in designing systems for the determination of real performance in personal dosimetry. (author)

  3. Rapid analysis of key radionuclides in urine and estimation of internal dose for nuclear accident emergency

    International Nuclear Information System (INIS)

    Zhao Shuquan; Hu Heping; Wu Mingyu; Zhu Guoying; Huang Shibin; Liu Shiming

    2005-01-01

    Objective: To estimate the internal doses of a Chinese visiting scholar in the Chernobyl accident. Methods: The contents of 134 Cs and 137 Cs in urine were measured using a Ge(Li) γ-spectrometer. Their internal doses were estimated according to ICRP reports. Dose review of 131I was performed referring to UNSCEAR 2000 report. Results: The effective dose equivalent from 134 Cs, 137 Cs and 131 I were 66 μSv, 88 μSv and 1728 μSv respectively. Their summation was 1.9 mSv. Conclusion: The internal dose from 131 I was 10 times higher than that from 134 Cs and 137 Cs. So, the earlier estimation of internal doses for 131 I is significant in evaluation on radiation injuries of a nuclear reactor accident. (authors)

  4. TU-F-CAMPUS-T-05: Replacement Computational Phantoms to Estimate Dose in Out-Of-Field Organs and Tissues

    Energy Technology Data Exchange (ETDEWEB)

    Gallagher, K [Oregon State University, Corvallis, Oregon (United States); Oregon Health and Science University, Portland, Oregon (United States); Tannous, J; Nabha, R; Feghali, J; Ayoub, Z; Jalbout, W; Youssef, B [American University of Beirut Medical Center, Beirut (Lebanon); Taddei, P [American University of Beirut Medical Center, Beirut (Lebanon); The University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: To estimate the absorbed dose in organs and tissues at risk for radiogenic cancer for children receiving photon radiotherapy for localized brain tumors (LBTs) by supplementing their missing body anatomies with those of replacement computational phantoms. Applied beyond the extent of the RT Images collected by computed tomography simulation, these phantoms included RT Image and RT Structure Set objects that encompassed sufficient extents and contours for dosimetric calculations. Method: Nine children, aged 2 to 14 years, who received three-dimensional conformal radiotherapy for low-grade LBTs, were randomly selected for this study under Institutional-Review-Board protocol. Because the extents of their RT Images were cranial only, they were matched for size and sex with patients from a previous study with larger extents and for whom contours of organs at risk for radiogenic cancer had already been delineated. Rigid fusion was performed between the patients’ data and those of the replacement computational phantoms using commercial software. In-field dose was calculated with a clinically-commissioned treatment planning system, and out-of-field dose was estimated with an analytical model. Results: Averaged over all nine children and normalized for a therapeutic dose of 54 Gy prescribed to the PTV, where the PTV is the GTV, the highest mean organ doses were 3.27, 2.41, 1.07, 1.02, 0.24, and 0.24 Gy in the non-tumor remainder, red bone marrow, thyroid, skin, breasts, and lungs, respectively. The mean organ doses ranged by a factor of 3 between the smallest and largest children. Conclusion: For children receiving photon radiotherapy for LBTs, we found their doses in organs at risk for second cancer to be non-negligible, especially in the non-tumor remainder, red bone marrow, thyroid, skin, breasts, and lungs. This study demonstrated the feasibility for patient dosimetry studies to augment missing patient anatomy by applying size- and sex-matched replacement

  5. Proof of concept and dose estimation with binary responses under model uncertainty.

    Science.gov (United States)

    Klingenberg, B

    2009-01-30

    This article suggests a unified framework for testing Proof of Concept (PoC) and estimating a target dose for the benefit of a more comprehensive, robust and powerful analysis in phase II or similar clinical trials. From a pre-specified set of candidate models, we choose the ones that best describe the observed dose-response. To decide which models, if any, significantly pick up a dose effect, we construct the permutation distribution of the minimum P-value over the candidate set. This allows us to find critical values and multiplicity adjusted P-values that control the familywise error rate of declaring any spurious effect in the candidate set as significant. Model averaging is then used to estimate a target dose. Popular single or multiple contrast tests for PoC, such as the Cochran-Armitage, Dunnett or Williams tests, are only optimal for specific dose-response shapes and do not provide target dose estimates with confidence limits. A thorough evaluation and comparison of our approach to these tests reveal that its power is as good or better in detecting a dose-response under various shapes with many more additional benefits: It incorporates model uncertainty in PoC decisions and target dose estimation, yields confidence intervals for target dose estimates and extends to more complicated data structures. We illustrate our method with the analysis of a Phase II clinical trial. Copyright (c) 2008 John Wiley & Sons, Ltd.

  6. Estimation of eye absorbed doses in head & neck radiotherapy practices using thermoluminescent detectors

    Directory of Open Access Journals (Sweden)

    Gh Bagheri

    2011-09-01

    Full Text Available  Determination of eye absorbed dose during head & neck radiotherapy is essential to estimate the risk of cataract. Dose measurements were made in 20 head & neck cancer patients undergoing 60Co radiotherapy using LiF(MCP thermoluminescent dosimeters. Head & neck cancer radiotherapy was delivered by fields using SAD & SSD techniques. For each patient, 3 TLD chips were placed on each eye. Head & neck dose was about 700-6000 cGy in 8-28 equal fractions. The range of eye dose is estimated to be (3.49-639.1 mGy with a mean of maximum dose (98.114 mGy, which is about 3 % of head & neck dose. Maximum eye dose was observed for distsnces of about 3 cm from edge of the field to eye.