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Sample records for targeting radiation dose

  1. Radiation Dose Measurement for High-Intensity Laser Interactions with Solid Targets at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Taiee [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-09-25

    A systematic study of photon and neutron radiation doses generated in high-intensity laser-solid interactions is underway at SLAC National Accelerator Laboratory. We found that these laser-solid experiments are being performed using a 25 TW (up to 1 J in 40 fs) femtosecond pulsed Ti:sapphire laser at the Linac Coherent Light Source’s (LCLS) Matter in Extreme Conditions (MEC) facility. Additionally, radiation measurements were performed with passive and active detectors deployed at various locations inside and outside the target chamber. Results from radiation dose measurements for laser-solid experiments at SLAC MEC in 2014 with peak intensity between 1018 to 7.1x1019 W/cm2 are presented.

  2. Toxicity risk of non-target organs at risk receiving low-dose radiation: case report

    International Nuclear Information System (INIS)

    Shueng, Pei-Wei; Lin, Shih-Chiang; Chang, Hou-Tai; Chong, Ngot-Swan; Chen, Yu-Jen; Wang, Li-Ying; Hsieh, Yen-Ping; Hsieh, Chen-Hsi

    2009-01-01

    The spine is the most common site for bone metastases. Radiation therapy is a common treatment for palliation of pain and for prevention or treatment of spinal cord compression. Helical tomotherapy (HT), a new image-guided intensity modulated radiotherapy (IMRT), delivers highly conformal dose distributions and provides an impressive ability to spare adjacent organs at risk, thus increasing the local control of spinal column metastases and decreasing the potential risk of critical organs under treatment. However, there are a lot of non-target organs at risk (OARs) occupied by low dose with underestimate in this modern rotational IMRT treatment. Herein, we report a case of a pathologic compression fracture of the T9 vertebra in a 55-year-old patient with cholangiocarcinoma. The patient underwent HT at a dose of 30 Gy/10 fractions delivered to T8-T10 for symptom relief. Two weeks after the radiotherapy had been completed, the first course of chemotherapy comprising gemcitabine, fluorouracil, and leucovorin was administered. After two weeks of chemotherapy, however, the patient developed progressive dyspnea. A computed tomography scan of the chest revealed an interstitial pattern with traction bronchiectasis, diffuse ground-glass opacities, and cystic change with fibrosis. Acute radiation pneumonitis was diagnosed. Oncologists should be alert to the potential risk of radiation toxicities caused by low dose off-targets and abscopal effects even with highly conformal radiotherapy

  3. Critical target and dose and dose-rate responses for the induction of chromosomal instability by ionizing radiation

    Science.gov (United States)

    Limoli, C. L.; Corcoran, J. J.; Milligan, J. R.; Ward, J. F.; Morgan, W. F.

    1999-01-01

    To investigate the critical target, dose response and dose-rate response for the induction of chromosomal instability by ionizing radiation, bromodeoxyuridine (BrdU)-substituted and unsubstituted GM10115 cells were exposed to a range of doses (0.1-10 Gy) and different dose rates (0.092-17.45 Gy min(-1)). The status of chromosomal stability was determined by fluorescence in situ hybridization approximately 20 generations after irradiation in clonal populations derived from single progenitor cells surviving acute exposure. Overall, nearly 700 individual clones representing over 140,000 metaphases were analyzed. In cells unsubstituted with BrdU, a dose response was found, where the probability of observing delayed chromosomal instability in any given clone was 3% per gray of X rays. For cells substituted with 25-66% BrdU, however, a dose response was observed only at low doses (1.0 Gy), the incidence of chromosomal instability leveled off. There was an increase in the frequency and complexity of chromosomal instability per unit dose compared to cells unsubstituted with BrdU. The frequency of chromosomal instability appeared to saturate around approximately 30%, an effect which occurred at much lower doses in the presence of BrdU. Changing the gamma-ray dose rate by a factor of 190 (0.092 to 17.45 Gy min(-1)) produced no significant differences in the frequency of chromosomal instability. The enhancement of chromosomal instability promoted by the presence of the BrdU argues that DNA comprises at least one of the critical targets important for the induction of this end point of genomic instability.

  4. A novel concept for tumour targeting with radiation: Inverse dose-painting or targeting the "Low Drug Uptake Volume".

    Science.gov (United States)

    Yaromina, Ala; Granzier, Marlies; Biemans, Rianne; Lieuwes, Natasja; van Elmpt, Wouter; Shakirin, Georgy; Dubois, Ludwig; Lambin, Philippe

    2017-09-01

    We tested a novel treatment approach combining (1) targeting radioresistant hypoxic tumour cells with the hypoxia-activated prodrug TH-302 and (2) inverse radiation dose-painting to boost selectively non-hypoxic tumour sub-volumes having no/low drug uptake. 18 F-HX4 hypoxia tracer uptake measured with a clinical PET/CT scanner was used as a surrogate of TH-302 activity in rhabdomyosarcomas growing in immunocompetent rats. Low or high drug uptake volume (LDUV/HDUV) was defined as 40% of the GTV with the lowest or highest 18 F-HX4 uptake, respectively. Two hours post TH-302/saline administration, animals received either single dose radiotherapy (RT) uniformly (15 or 18.5Gy) or a dose-painted non-uniform radiation (15Gy) with 50% higher dose to LDUV or HDUV (18.5Gy). Treatment plans were created using Eclipse treatment planning system and radiation was delivered using VMAT. Tumour response was quantified as time to reach 3 times starting tumour volume. Non-uniform RT boosting tumour sub-volume with low TH-302 uptake (LDUV) was superior to the same dose escalation to HDUV (pvolume with no/low activity of hypoxia-activated prodrugs. This strategy applies on average a lower radiation dose and is as effective as uniform dose escalation to the entire tumour. It could be applied to other type of drugs provided that their distribution can be imaged. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  5. Low-dose radiation potentiates the therapeutic efficacy of folate receptor-targeted hapten therapy.

    Science.gov (United States)

    Sega, Emanuela I; Lu, Yingjuan; Ringor, Michael; Leamon, Christopher P; Low, Philip S

    2008-06-01

    Human cancers frequently overexpress a high-affinity cell-surface receptor for the vitamin folic acid. Highly immunogenic haptens can be targeted to folate receptor-expressing cell surfaces by administration of folate-hapten conjugates, rendering the decorated tumor cell surfaces more recognizable by the immune system. Treatment of antihapten-immunized mice with folate-hapten constructs results in elimination of moderately sized tumors by the immune system. However, when subcutaneous tumors exceed 300 mm(3) before initiation of therapy, antitumor activity is significantly decreased. In an effort to enhance the efficacy of folate-targeted hapten immunotherapy (FTHI) against large tumors, we explored the combination of targeted hapten immunotherapy with low-dose radiotherapy. Mice bearing 300-mm(3) subcutaneous tumors were treated concurrently with FTHI (500 nmol/kg of folate conjugated to fluorescein isothiocyanate, 20,000 U/dose of interleukin 2, and 25,000 U/dose of interferon alpha) and low-dose radiotherapy (3 Gy/dose focused directly on the desired tumor mass). The efficacy of therapy was evaluated by measuring tumor volume. Tumor growth analyses show that radiotherapy synergizes with FTHI in antihapten-immunized mice, thereby allowing for cures of animals bearing tumors greater than 300 mm(3). More importantly, nonirradiated distal tumor masses in animals containing locally irradiated tumors also showed improved response to hapten immunotherapy, suggesting that not all tumor lesions must be identified and irradiated to benefit from the combination therapy. These results suggest that simultaneous treatment with FTHI and radiation therapy can enhance systemic antitumor activity in tumor-bearing mice.

  6. Low-Dose Radiation Potentiates the Therapeutic Efficacy of Folate Receptor-Targeted Hapten Therapy

    International Nuclear Information System (INIS)

    Sega, Emanuela I.; Lu Yingjuan; Ringor, Michael; Leamon, Christopher P.; Low, Philip S.

    2008-01-01

    Purpose: Human cancers frequently overexpress a high-affinity cell-surface receptor for the vitamin folic acid. Highly immunogenic haptens can be targeted to folate receptor-expressing cell surfaces by administration of folate-hapten conjugates, rendering the decorated tumor cell surfaces more recognizable by the immune system. Treatment of antihapten-immunized mice with folate-hapten constructs results in elimination of moderately sized tumors by the immune system. However, when subcutaneous tumors exceed 300 mm 3 before initiation of therapy, antitumor activity is significantly decreased. In an effort to enhance the efficacy of folate-targeted hapten immunotherapy (FTHI) against large tumors, we explored the combination of targeted hapten immunotherapy with low-dose radiotherapy. Methods and Materials: Mice bearing 300-mm 3 subcutaneous tumors were treated concurrently with FTHI (500 nmol/kg of folate conjugated to fluorescein isothiocyanate, 20,000 U/dose of interleukin 2, and 25,000 U/dose of interferon α) and low-dose radiotherapy (3 Gy/dose focused directly on the desired tumor mass). The efficacy of therapy was evaluated by measuring tumor volume. Results: Tumor growth analyses show that radiotherapy synergizes with FTHI in antihapten-immunized mice, thereby allowing for cures of animals bearing tumors greater than 300 mm 3 . More importantly, nonirradiated distal tumor masses in animals containing locally irradiated tumors also showed improved response to hapten immunotherapy, suggesting that not all tumor lesions must be identified and irradiated to benefit from the combination therapy. Conclusions: These results suggest that simultaneous treatment with FTHI and radiation therapy can enhance systemic antitumor activity in tumor-bearing mice

  7. Targeted computerised tomography scanning of the ankle syndesmosis with low dose radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Kotwal, Rahul [Princess of Wales Hospital, Bridgend (United Kingdom); Rath, Narendra [Royal Gwent Hospital, Newport (United Kingdom); Paringe, Vishal; Hemmadi, Sandeep; Thomas, Rhys; Lyons, Kath [University Hospital of Wales, Cardiff (United Kingdom)

    2016-03-15

    To devise a new protocol for targeted CT scanning of the distal tibiofibular syndesmosis with minimal radiation exposure to patients. We also aimed to correlate the reduction of the syndesmosis as seen on CT scans with the functional outcome of patients. Prospective study. Forty adults undergoing surgical stabilisation of an acute distal tibiofibular syndesmosis injury were recruited. A targeted five-cut computerised tomography scan protocol was developed. The radiation exposure to the patient with this protocol was only 0.002 mSv. Scans were performed 12 weeks after surgery. The contralateral ankle of every patient was used as a control to determine the accuracy of the reduction of the syndesmosis for that individual patient. American Orthopaedic Foot and Ankle Society (AOFAS) scores were obtained at a minimum of 1 year after surgery. After considering the exclusions, 36 patients formed the study group. A wide variation was observed in the anatomy of the normal syndesmosis. If we considered a difference of more than 2 mm between the normal and injured syndesmosis relationship as significant, 15 (41.6 %) of our patients had a significant difference between the injured and normal sides. AOFAS scores were available for 13 of these patients and were good to excellent in 11(84.6 %). Our study describes a reliable new CT scanning technique for the distal tibiofibular syndesmosis using only five cuts and a low-radiation-dose protocol. Clinical correlation of the findings on the scan with functional outcomes suggests that routine post-operative CT of the syndesmosis is probably not justified. (orig.)

  8. Targeted computerised tomography scanning of the ankle syndesmosis with low dose radiation exposure

    International Nuclear Information System (INIS)

    Kotwal, Rahul; Rath, Narendra; Paringe, Vishal; Hemmadi, Sandeep; Thomas, Rhys; Lyons, Kath

    2016-01-01

    To devise a new protocol for targeted CT scanning of the distal tibiofibular syndesmosis with minimal radiation exposure to patients. We also aimed to correlate the reduction of the syndesmosis as seen on CT scans with the functional outcome of patients. Prospective study. Forty adults undergoing surgical stabilisation of an acute distal tibiofibular syndesmosis injury were recruited. A targeted five-cut computerised tomography scan protocol was developed. The radiation exposure to the patient with this protocol was only 0.002 mSv. Scans were performed 12 weeks after surgery. The contralateral ankle of every patient was used as a control to determine the accuracy of the reduction of the syndesmosis for that individual patient. American Orthopaedic Foot and Ankle Society (AOFAS) scores were obtained at a minimum of 1 year after surgery. After considering the exclusions, 36 patients formed the study group. A wide variation was observed in the anatomy of the normal syndesmosis. If we considered a difference of more than 2 mm between the normal and injured syndesmosis relationship as significant, 15 (41.6 %) of our patients had a significant difference between the injured and normal sides. AOFAS scores were available for 13 of these patients and were good to excellent in 11(84.6 %). Our study describes a reliable new CT scanning technique for the distal tibiofibular syndesmosis using only five cuts and a low-radiation-dose protocol. Clinical correlation of the findings on the scan with functional outcomes suggests that routine post-operative CT of the syndesmosis is probably not justified. (orig.)

  9. Phantom study of radiation doses outside the target volume brachytherapy versus external radiotherapy of early breast cancer

    International Nuclear Information System (INIS)

    Johansson, Bengt; Persson, Essie; Westman, Gunnar; Persliden, Jan

    2003-01-01

    Background and purpose: Brachytherapy is sometimes suggested as an adjuvant treatment after surgery of some tumours. When introducing this, it would be useful to have an estimate of the dose distribution to different body sites, both near and distant to target, comparing conventional external irradiation to brachytherapy. The aim of the present study was to determine radiation doses with both methods at different body sites, near and distant to target, in an experimental situation on an operated left sided breast cancer on a female Alderson phantom. Methods: Five external beam treatments with isocentric tangential fields were given by a linear accelerator. A specified dose of 1.0 Gy was given to the whole left sided breast volume. Five interstitial brachytherapy treatments were given to the upper, lateral quadrant of the left breast by a two plane, 10 needles implant. A dose of 1.0 Gy specified according to the Paris system was administered by a pulsed dose rate afterloading machine. Absorbed dose in different fixed dose points were measured by thermoluminescence dosimeters. Results: Both methods yielded an absorbed dose of the same size to the bone marrow and internal organs distant to target, 1.0-1.4% of the prescribed dose. There was a trend of lower doses to the lower half of the trunk and higher doses to the upper half of the trunk, respectively, by brachytherapy. A 90% reduction of absorbed dose with brachytherapy compared to external irradiation was found in the near-target region within 5 cm from target boundary where parts of the left lung and the heart are situated. If an adjuvant dose of 50 Gy is given with the external radiotherapy and brachytherapy, the absorbed dose in a part of the myocardium could be reduced from 31.8 to 2.1 Gy. Conclusions: Near target, brachytherapy yielded a considerably lower absorbed dose which is of special importance when considering radiation effects on the myocard and lungs. We could not demonstrate any difference of

  10. Imprinted genes and transpositions: epigenomic targets for low dose radiation effects. Final report

    International Nuclear Information System (INIS)

    Jirtle, Randy L.

    2012-01-01

    The overall hypothesis of this grant application is that low dose ionizing radiation (LDIR) elicits adaptive responses in part by causing heritable DNA methylation changes in the epigenome. This novel postulate was tested by determining if the level of DNA methylation at the Agouti viable yellow (A vy ) metastable locus is altered, in a dose-dependent manner, by low dose radiation exposure ( vy locus in a sex-specific manner (p=0.004). Average DNA methylation was significantly increased in male offspring exposed to doses between 0.7 cGy and 7.6 cGy with maximum effects at 1.4 cGy and 3.0 cGy (p<0.01). Offspring coat color was concomitantly shifted towards pseudoagouti (p<0.01). Maternal dietary antioxidant supplementation mitigated both the DNA methylation changes and coat color shift in the irradiated offspring (p<0.05). Thus, LDIR exposure during gestation elicits epigenetic alterations that lead to positive adaptive phenotypic changes that are negated with antioxidants, indicating they are mediated in part by oxidative stress. These findings provide evidence that in the isogenic Avy mouse model epigenetic alterations resulting from LDIR play a role in radiation hormesis, bringing into question the assumption that every dose of radiation is harmful. Our findings not only have significant implications concerning the mechanism of hormesis, but they also emphasize the potential importance of this phenomenon in determining human risk at low radiation doses. Since the epigenetic regulation of genes varies markedly between species, the effect of LDIR on other epigenetically labile genes (e.g. imprinted genes) in animals and humans needs to be defined

  11. Low doses and non-targeted effects in environmental radiation protection; where are we now and where should we go?

    Science.gov (United States)

    Mothersill, Carmel; Rusin, Andrej; Seymour, Colin

    2017-11-01

    The field of low dose radiobiology has advanced considerably in the last 30 years from small indications in the 1980's that all was not simple, to a paradigm shift which occurred during the 1990's, which severely dented the dose-driven models and DNA centric theories which had dominated until then. However while the science has evolved, the application of that science in environmental health protection has not. A reason for this appears to be the uncertainties regarding the shape of the low dose response curve, which lead regulators to adopt a precautionary approach to radiation protection. Radiation protection models assume a linear relationship between dose (i.e. energy deposition) and effect (in this case probability of an adverse DNA interaction leading to a mutation). This model does not consider non-targeted effects (NTE) such as bystander effects or delayed effects, which occur in progeny cells or offspring not directly receiving energy deposition from the dose. There is huge controversy concerning the role of NTE with some saying they reflect "biology" and that repair and homeostatic mechanisms sort out the apparent damage while others consider them to be a class of damage which increases the size of the target. One thing which has recently become apparent is that NTE may be very critical for modelling long-term effects at the level of the population rather than the individual. The issue is that NTE resulting from an acute high dose such as occurred after the A-bomb or Chernobyl occur in parallel with chronic effects induced by the continuing residual effects due to radiation dose decay. This means that if ambient radiation doses are measured for example 25 years after the Chernobyl accident, they only represent a portion of the dose effect because the contribution of NTE is not included. Copyright © 2017. Published by Elsevier Inc.

  12. Radiosensitive target in the early mouse embryo exposed to very low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Wiley, Lynn M.; Raabe, Otto G.; Khan, Rakhshi; Straume, Tore

    1994-01-01

    We exposed mouse preimplantation embryos in vitro to either tritiated water (HTO) or tritiated thymidine (TdR) to determine whether the radiosensitive target was nuclear or extranuclear for embryonic cell proliferation disadvantage in the mouse embryo chimera assay. 8-cell embryos were incubated in either HTO or TdR for 2 h and paired with non-irradiated control embryos to form chimeras. Chimeras were cultured for an average of 20.2 h to allow for 2-3 cell cycles and then partially dissociated to obtain the number of progeny cells contributed by the two partner embryos for each chimera. These values were expressed as a 'proliferation ratio' (number of cells from the irradiated embryo: total number of cells in the chimera). A ratio significantly less than 0.50 indicates that the experimental embryo expressed an embryonic cell proliferation disadvantage, which is the endpoint of this assay. The activity concentrations of HTO and TdR were adjusted so that both would deliver comparable mean absorbed nuclear doses during the combined initial 2-h irradiation incubation and subsequent 20.2 h chimera incubation periods. Although nuclear doses were comparable under these conditions, the extranuclear dose delivered by the uniformly distributed HTO was about 100 times greater than the extranuclear dose delivered by TdR for each given nuclear dose. Consequently, obtaining mean TdR proliferation ratios≤mean HTO proliferation ratios would be evidence for a nuclear target while obtaining mean HTO proliferation ratios< mean TdR proliferation ratios would be evidence for an extranuclear target. TdR consistently produced lower mean proliferation ratios over a range of doses from 0.14 Gy to 0.43 Gy. Therefore, we conclude that the radiosensitive target for this endpoint is nuclear

  13. Low Z target switching to increase tumor endothelial cell dose enhancement during gold nanoparticle-aided radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Berbeco, Ross I., E-mail: rberbeco@partners.org; Detappe, Alexandre [Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115 (United States); Tsiamas, Panogiotis [Department of Radiation Oncology, St. Jude Children’s Hospital, Memphis, Tennessee 38105 (United States); Parsons, David; Yewondwossen, Mammo; Robar, James [Department of Radiation Oncology and Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 1V7 (Canada)

    2016-01-15

    Purpose: Previous studies have introduced gold nanoparticles as vascular-disrupting agents during radiation therapy. Crucial to this concept is the low energy photon content of the therapy radiation beam. The authors introduce a new mode of delivery including a linear accelerator target that can toggle between low Z and high Z targets during beam delivery. In this study, the authors examine the potential increase in tumor blood vessel endothelial cell radiation dose enhancement with the low Z target. Methods: The authors use Monte Carlo methods to simulate delivery of three different clinical photon beams: (1) a 6 MV standard (Cu/W) beam, (2) a 6 MV flattening filter free (Cu/W), and (3) a 6 MV (carbon) beam. The photon energy spectra for each scenario are generated for depths in tissue-equivalent material: 2, 10, and 20 cm. The endothelial dose enhancement for each target and depth is calculated using a previously published analytic method. Results: It is found that the carbon target increases the proportion of low energy (<150 keV) photons at 10 cm depth to 28% from 8% for the 6 MV standard (Cu/W) beam. This nearly quadrupling of the low energy photon content incident on a gold nanoparticle results in 7.7 times the endothelial dose enhancement as a 6 MV standard (Cu/W) beam at this depth. Increased surface dose from the low Z target can be mitigated by well-spaced beam arrangements. Conclusions: By using the fast-switching target, one can modulate the photon beam during delivery, producing a customized photon energy spectrum for each specific situation.

  14. Imprinted genes and transpositions: epigenomic targets for low dose radiation effects. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jirtle, Randy L.

    2012-10-11

    The overall hypothesis of this grant application is that low dose ionizing radiation (LDIR) elicits adaptive responses in part by causing heritable DNA methylation changes in the epigenome. This novel postulate was tested by determining if the level of DNA methylation at the Agouti viable yellow (A{sup vy}) metastable locus is altered, in a dose-dependent manner, by low dose radiation exposure (<10 cGy) during early gestation. This information is particularly important to ascertain given the increased use of CT scans in disease diagnosis, increased number of people predicted to live and work in space, and the present concern about radiological terrorism. We showed for the first time that LDIR significantly increased DNA methylation at the A{sup vy} locus in a sex-specific manner (p=0.004). Average DNA methylation was significantly increased in male offspring exposed to doses between 0.7 cGy and 7.6 cGy with maximum effects at 1.4 cGy and 3.0 cGy (p<0.01). Offspring coat color was concomitantly shifted towards pseudoagouti (p<0.01). Maternal dietary antioxidant supplementation mitigated both the DNA methylation changes and coat color shift in the irradiated offspring (p<0.05). Thus, LDIR exposure during gestation elicits epigenetic alterations that lead to positive adaptive phenotypic changes that are negated with antioxidants, indicating they are mediated in part by oxidative stress. These findings provide evidence that in the isogenic Avy mouse model epigenetic alterations resulting from LDIR play a role in radiation hormesis, bringing into question the assumption that every dose of radiation is harmful. Our findings not only have significant implications concerning the mechanism of hormesis, but they also emphasize the potential importance of this phenomenon in determining human risk at low radiation doses. Since the epigenetic regulation of genes varies markedly between species, the effect of LDIR on other epigenetically labile genes (e.g. imprinted genes) in

  15. Doses to radiation sensitive organs and structures located outside the radiotherapeutic target volume for four treatment situations

    International Nuclear Information System (INIS)

    Foo, M.L.; McCullough, E.C.; Foote, R.L.; Pisansky, T.M.; Shaw, E.G.

    1993-01-01

    This study documents dosage to radiation sensitive organs/structures located outside the radiotherapeutic target volume for four treatment situations: (a) head and neck, (b) brain (pituitary and temporal lobe), (c) breast and (d) pelvis. Clinically relevant treatment fields were simulated on a tissue-equivalent anthropomorphic phantom and subsequently irradiated with Cobalt-60 gamma rays, 6- and 18-MV x-ray beams. Thermoluminescent dosimeters and diodes were used to measure absorbed dose. The head and neck treatment resulted in significant doses of radiation to the lens and thyroid gland. The total treatment lens dose (300-400 cGy) could be cataractogenic while measured thyroid doses (1000-8000 cGy) have the potential of causing chemical hypothyroidism, thyroid neoplasms, Graves' disease and hyperparathyroidism. Total treatment retinal (400-700 cGy) and pituitary (460-1000 cGy) doses are below that considered capable of producing chronic disease. The pituitary treatment studied consisted of various size parallel opposed lateral and vertex fields (4 x 4 through 8 x 8 cm). The lens dose (40-200 cGy) with all field sizes is below those of clinical concern. Parotid doses (130-1200 cGy) and thyroid doses (350-600 cGy) are in a range where temporary xerostomia (parotid) and thyroid neoplasia development are a reasonable possibility. The retinal dose (4000 cGy) from the largest field size (8 x 8 cm 2 ) is in the range where retinopathy has been reported. The left temporal lobe treatment also used parallel opposed lateral and vertex fields (7 x 7 and 10 x 10 cm). Doses to the pituitary gland (5200-6200 cGy), both parotids (200-6900 cGy), left lens (200-300 cGy), and left retina (1700-4500 cGy) are capable of causing significant future clinical problems. Right-sided structures received insignificant doses. Secondary malignancies could result from the measured total treatment thyroid doses (670-980 cGy). 82 refs., 7 figs., 5 tabs

  16. Registration of radiation doses

    International Nuclear Information System (INIS)

    2000-02-01

    In Finland the Radiation and Nuclear Safety Authority (STUK) is maintaining the register (called Dose Register) of the radiation exposure of occupationally exposed workers in order to ensure compliance with the principles of optimisation and individual protection. The guide contains a description of the Dose Register and specifies the responsibilities of the party running a radiation practice to report the relevant information to the Dose Register

  17. Assessing patient characteristics and radiation-induced non-targeted effects in vivo for high dose-rate (HDR) brachytherapy.

    Science.gov (United States)

    Pinho, Christine; Timotin, Emilia; Wong, Raimond; Sur, Ranjan K; Hayward, Joseph E; Farrell, Thomas J; Seymour, Colin; Mothersill, Carmel

    2015-01-01

    To test whether blood, urine, and tissue based colony-forming assays are a useful clinical detection tool for assessing fractionated treatment responses and non-targeted radiation effects in bystander cells. To assess patients' responses to radiation treatments, blood serum, urine, and an esophagus explant-based in vivo colony-forming assay were used from oesophageal carcinoma patients. These patients underwent three fractions of high dose rate (HDR) intraluminal brachytherapy (ILBT). Human keratinocyte reporters exposed to blood sera taken after the third fraction of brachytherapy had a significant increase in cloning efficiency compared to baseline samples (p fractions for the blood sera data only. Patient characteristics such as gender had no statistically significant effect (p > 0.05). Large variability was observed among the patients' tissue samples, these colony-forming assays showed no significant changes throughout fractionated brachytherapy (p > 0.05). Large inter-patient variability was found in the urine and tissue based assays, so these techniques were discontinued. However, the simple blood-based assay had much less variability. This technique may have future applications as a biological dosimeter to predict treatment outcome and assess non-targeted radiation effects.

  18. Radiation doses to Finns

    International Nuclear Information System (INIS)

    Rantalainen, L.

    1996-01-01

    The estimated annual radiation doses to Finns have been reduced in the recent years without any change in the actual radiation environment. This is because the radiation types have been changed. The risk factors will probably be changed again in the future, because recent studies show discrepancies in the neutron dosimetry concerning the city of Hiroshima. Neutron dosimetry discrepancy has been found between the predicted and estimated neutron radiation. The prediction of neutron radiation is calculated by Monte Carlo simulations, which have also been used when designing recommendations for the limits of radiation doses (ICRP60). Estimation of the neutron radiation is made on the basis of measured neutron activation of materials in the city. The estimated neutron dose beyond 1 km is two to ten, or more, times as high as the predicted dose. This discrepancy is important, because the most relevant distances with respect to radiation risk evaluation are between 1 and 2 km. Because of this discrepancy, the present radiation risk factors for gamma and neutron radiation, which rely on the Monte Carlo calculations, are false, too. The recommendations of ICRP60 have been adopted in a few countries, including Finland, and they affect the planned common limits of the EU. It is questionable whether happiness is increased by adopting false limits, even if they are common. (orig.) (2 figs., 1 tab.)

  19. Radiation dose in vertebroplasty

    International Nuclear Information System (INIS)

    Mehdizade, A.; Lovblad, K.O.; Wilhelm, K.E.; Somon, T.; Wetzel, S.G.; Kelekis, A.D.; Yilmaz, H.; Abdo, G.; Martin, J.B.; Viera, J.M.; Ruefenacht, D.A.

    2004-01-01

    We wished to measure the absorbed radiation dose during fluoroscopically controlled vertebroplasty and to assess the possibility of deterministic radiation effects to the operator. The dose was measured in 11 consecutive procedures using thermoluminescent ring dosimeters on the hand of the operator and electronic dosimeters inside and outside of the operator's lead apron. We found doses of 0.022-3.256 mGy outside and 0.01-0.47 mGy inside the lead apron. Doses on the hand were higher, 0.5-8.5 mGy. This preliminary study indicates greater exposure to the operator's hands than expected from traditional apron measurements. (orig.)

  20. Planning Target Volume D95 and Mean Dose Should Be Considered for Optimal Local Control for Stereotactic Ablative Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Lina [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhou, Shouhao [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Balter, Peter [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Shen, Chan [Department of Health Service Research, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gomez, Daniel R.; Welsh, James D.; Lin, Steve H. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chang, Joe Y., E-mail: jychang@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2016-07-15

    Purpose: To identify the optimal dose parameters predictive for local/lobar control after stereotactic ablative radiation therapy (SABR) in early-stage non-small cell lung cancer (NSCLC). Methods and Materials: This study encompassed a total of 1092 patients (1200 lesions) with NSCLC of clinical stage T1-T2 N0M0 who were treated with SABR of 50 Gy in 4 fractions or 70 Gy in 10 fractions, depending on tumor location/size, using computed tomography-based heterogeneity corrections and a convolution superposition calculation algorithm. Patients were monitored by chest CT or positron emission tomography/CT and/or biopsy after SABR. Factors predicting local/lobar recurrence (LR) were determined by competing risk multivariate analysis. Continuous variables were divided into 2 subgroups at cutoff values identified by receiver operating characteristic curves. Results: At a median follow-up time of 31.7 months (interquartile range, 14.8-51.3 months), the 5-year time to local recurrence within the same lobe and overall survival rates were 93.8% and 44.8%, respectively. Total cumulative number of patients experiencing LR was 40 (3.7%), occurring at a median time of 14.4 months (range, 4.8-46 months). Using multivariate competing risk analysis, independent predictive factors for LR after SABR were minimum biologically effective dose (BED{sub 10}) to 95% of planning target volume (PTVD95 BED{sub 10}) ≤86 Gy (corresponding to PTV D95 physics dose of 42 Gy in 4 fractions or 55 Gy in 10 fractions) and gross tumor volume ≥8.3 cm{sup 3}. The PTVmean BED{sub 10} was highly correlated with PTVD95 BED{sub 10.} In univariate analysis, a cutoff of 130 Gy for PTVmean BED{sub 10} (corresponding to PTVmean physics dose of 55 Gy in 4 fractions or 75 Gy in 10 fractions) was also significantly associated with LR. Conclusions: In addition to gross tumor volume, higher radiation dose delivered to the PTV predicts for better local/lobar control. We recommend that both PTVD95 BED

  1. Non-targeted effects of low dose ionizing radiation act via TGF-beta to promote mammary carcinogenesis

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a genome-wide approach to identifying genes persistently induced in the mouse mammary gland by acute whole body low dose ionizing radiation (10cGy) 1 and 4...

  2. Modern Radiation Therapy for Nodal Non-Hodgkin Lymphoma—Target Definition and Dose Guidelines From the International Lymphoma Radiation Oncology Group

    Energy Technology Data Exchange (ETDEWEB)

    Illidge, Tim, E-mail: Tim.Illidge@ics.manchester.ac.uk [Institute of Cancer Sciences, University of Manchester, Manchester Academic Health Sciences Centre, The Christie National Health Service Foundation Trust, Manchester (United Kingdom); Specht, Lena [Department of Oncology and Hematology, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Yahalom, Joachim [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Aleman, Berthe [Department of Radiotherapy, The Netherlands Cancer Institute, Amsterdam (Netherlands); Berthelsen, Anne Kiil [Department of Radiation Oncology and PET Centre, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Constine, Louis [Departments of Radiation Oncology and Pediatrics, James P. Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York (United States); Dabaja, Bouthaina [Division of Radiation Oncology, Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dharmarajan, Kavita [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ng, Andrea [Department of Radiation Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Harvard University, Boston, Massachusetts (United States); Ricardi, Umberto [Radiation Oncology Unit, Department of Oncology, University of Torino, Torino (Italy); Wirth, Andrew [Division of Radiation Oncology, Peter MacCallum Cancer Institute, St. Andrews Place, East Melbourne (Australia)

    2014-05-01

    Radiation therapy (RT) is the most effective single modality for local control of non-Hodgkin lymphoma (NHL) and is an important component of therapy for many patients. Many of the historic concepts of dose and volume have recently been challenged by the advent of modern imaging and RT planning tools. The International Lymphoma Radiation Oncology Group (ILROG) has developed these guidelines after multinational meetings and analysis of available evidence. The guidelines represent an agreed consensus view of the ILROG steering committee on the use of RT in NHL in the modern era. The roles of reduced volume and reduced doses are addressed, integrating modern imaging with 3-dimensional planning and advanced techniques of RT delivery. In the modern era, in which combined-modality treatment with systemic therapy is appropriate, the previously applied extended-field and involved-field RT techniques that targeted nodal regions have now been replaced by limiting the RT to smaller volumes based solely on detectable nodal involvement at presentation. A new concept, involved-site RT, defines the clinical target volume. For indolent NHL, often treated with RT alone, larger fields should be considered. Newer treatment techniques, including intensity modulated RT, breath holding, image guided RT, and 4-dimensional imaging, should be implemented, and their use is expected to decrease significantly the risk for normal tissue damage while still achieving the primary goal of local tumor control.

  3. Doses from radiation exposure

    International Nuclear Information System (INIS)

    Menzel, H-G.; Harrison, J.D.

    2012-01-01

    Practical implementation of the International Commission on Radiological Protection’s (ICRP) system of protection requires the availability of appropriate methods and data. The work of Committee 2 is concerned with the development of reference data and methods for the assessment of internal and external radiation exposure of workers and members of the public. This involves the development of reference biokinetic and dosimetric models, reference anatomical models of the human body, and reference anatomical and physiological data. Following ICRP’s 2007 Recommendations, Committee 2 has focused on the provision of new reference dose coefficients for external and internal exposure. As well as specifying changes to the radiation and tissue weighting factors used in the calculation of protection quantities, the 2007 Recommendations introduced the use of reference anatomical phantoms based on medical imaging data, requiring explicit sex averaging of male and female organ-equivalent doses in the calculation of effective dose. In preparation for the calculation of new dose coefficients, Committee 2 and its task groups have provided updated nuclear decay data (ICRP Publication 107) and adult reference computational phantoms (ICRP Publication 110). New dose coefficients for external exposures of workers are complete (ICRP Publication 116), and work is in progress on a series of reports on internal dose coefficients to workers from inhaled and ingested radionuclides. Reference phantoms for children will also be provided and used in the calculation of dose coefficients for public exposures. Committee 2 also has task groups on exposures to radiation in space and on the use of effective dose.

  4. Target and peripheral dose from radiation sector motions accompanying couch repositioning of patient coordinates with the Gamma Knife® Perfexion™

    International Nuclear Information System (INIS)

    Tran, Tuan-Anh; Wu, Vincent; Malhotra, Harish; Steinman, James P.; Prasad, Dheerendra; Podgorsak, Matthew B.

    2011-01-01

    The GammaPlan ™ treatment planning system (TPS) does not fully account for shutter dose when multiple shots are required to deliver a patient’s treatment. The unaccounted exposures to the target site and its periphery are measured in this study. The collected data are compared to a similar effect from the Gamma Knife ® model 4C. A stereotactic head frame was attached to a Leksell ® 16 cm diameter spherical phantom; using a fiducial-box, CT images of the phantom were acquired and registered in the TPS. Measurements give the relationship of measured dose to the number of repositions with the patient positioning system (PPS) and to the collimator size. An absorbed dose of 10 Gy to the 50% isodose line was prescribed to the target site and all measurements were acquired with an ionization chamber. Measured dose increases with frequency of repositioning and with collimator size. As the radiation sectors transition between the beam on and beam off states, the target receives more shutter dose than the periphery. Shutter doses of 3.53±0.04 and 1.59±0.04 cGy/reposition to the target site are observed for the 16 and 8 mm collimators, respectively. The target periphery receives additional dose that varies depending on its position relative to the target. The radiation sector motions for the Gamma Knife ® Perfexion ™ result in an additional dose due to the shutter effect. The magnitude of this exposure is comparable to that measured for the model 4C

  5. The software program Peridose to calculate the fetal dose or dose to other critical structures outside the target area in radiation therapy

    International Nuclear Information System (INIS)

    Giessen, P.H. van der

    2001-01-01

    An accurate estimate of the dose outside the target area is of utmost importance when pregnant patients have to undergo radiotherapy, something that occurs in every radiotherapy department once in a while. Such peripheral doses (PD) are also of interest for late effects risk estimations for doses to specific organs as well as estimations of dose to pacemakers. A software program, Peridose, is described to allow easy calculation of this peripheral dose. The calculation is based on data from many publications on peripheral dose measurements, including those by the author. Clinical measurements have shown that by using data averaged over many measurements and different machine types PDs can be estimated with an accuracy of ± 60% (2 standard deviations). The program allows easy and fairly accurate estimates of peripheral doses in patients. Further development to overcome some of the constraints and limitations is desirable. The use of average data is to be preferred if general applicability is to be maintained. (author)

  6. Radiation dose electrophysiology procedures

    International Nuclear Information System (INIS)

    Hernandez-Armas, J.; Rodriguez, A.; Catalan, A.; Hernandez Armas, O.; Luque Japon, L.; Moral, S.; Barroso, L.; Rfuez-Hdez, R.

    2006-01-01

    The aim of this paper has been to measure and analyse some of the parameters which are directly related with the doses given to patients in two electrophysiology procedures: diagnosis and ablation with radiofrequency. 16 patients were considered in this study. 13 them had an ablation with radiofrequency at the Unit of Electrophysiology at the University Hospital of the Canaries, La Laguna., Tenerife. The results of skin doses, in the ablation cases, were higher than 2 Gy (threshold of some deterministic effects). The average value was 1.1 Gy. The personal doses, measured under the lead apron, for physician and nurses were 4 and 3 micro Sievert. These results emphasised the necessity of radiation protection measures in order to reduce, ad much as possible, the doses to patients. (Author)

  7. Targeting the adventitia with intracoronary beta-radiation: comparison of two dose prescriptions and the role of centering coronary arteries

    International Nuclear Information System (INIS)

    Kaluza, Grzegorz L.; Jenkins, Todd P.; Mourtada, Firas A.; Ali, Nadir M.; Lee, David P.; Okura, Hiroyuki; Fitzgerald, Peter J.; Raizner, Albert E.

    2002-01-01

    Purpose: To compare by intravascular ultrasound (IVUS) the efficacy of delivering the prescribed dose to the adventitia between two commonly used dose prescriptions for intracoronary radiotherapy. Methods and Materials: In 59 human postangioplasty coronary vessels, one IVUS cross-section (1 mm thick) with the highest plaque burden was used for creating dose-volume histograms with different hypothetical positions of the source. Results: On average, prescription to 1 mm beyond lumen surface resulted in delivery of the prescribed dose (20 Gy ± 20%) to a higher fraction of adventitial volume than with the prescription to 2 mm from the source, with source placed in vessel center, lumen center, or in the IVUS catheter position. Source placement in the lumen center resulted in a low dose heterogeneity to the adventitia and the least dose heterogeneity to the intima. Conclusions: Prescription to 1 mm beyond lumen surface appeared more effective in delivering the prescribed dose to the adventitia than the American Association of Physicists in Medicine (AAPM) recommended prescription to 2 mm from the source center. Moreover, centering the source in the lumen provides the better balance of effective adventitial targeting and intimal dose homogeneity. Modification of the current AAPM recommendation for dose prescription for intracoronary radiotherapy should be considered

  8. Doses from radiation exposure

    CERN Document Server

    Menzel, H G

    2012-01-01

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

  9. Radiation dose measurements

    International Nuclear Information System (INIS)

    1960-01-01

    About 200 scientists from 28 countries and 5 international organizations met at a symposium on radiation dosimetry held by the International Atomic Energy Agency in June 1960. The aim of the symposium was not so much the description of a large number of measuring instruments as a discussion of the methods used, with special emphasis on those problems which had become important in the context of recent developments, such as the measurement of mixed or very large doses

  10. Doses from Medical Radiation Sources

    Science.gov (United States)

    ... Medical Radiation Sources Michael G. Stabin, PhD, CHP Introduction Radiation exposures from diagnostic medical examinations are generally ... of exposure annually to natural background radiation. Plain Film X Rays Single Radiographs Effective Dose, mSv Skull ( ...

  11. Intercomparison of Dosimeters for Non-Target Organ Dose Measurements in Radiotherapy - Activity of EURADOS WG 9: Radiation Protection in Medicine

    International Nuclear Information System (INIS)

    Miljanic, S.; Knezevic, Z.; Bessieres, I.; Bordy, J.-M.; D'Agostino, E.; d'Errico, F.; di Fulvio, A.; Domingo, C.; Olko, P.; Stolarczyk; Silari, M.; Harrison, R.

    2011-01-01

    It has been known for a long time that patients treated with ionizing radiation carry a risk of developing radiation induced cancer in their lifetimes. It is recognized that cure/survival rates in radiotherapy are increasing, but so are secondary cancers. These occurrences are amplified by the early detection of disease in younger patients. These patients are cured from the primary disease and have long life-expectancies, which increase their chances of developing secondary malignancies. The motivation of the EURADOS Working Group 9 (WG 9) ''Radiation protection dosimetry in medicine'' is to assess undue non-target patient doses in radiotherapy and the related risks of secondary malignancy with the most accredited available methods and with the emphasis on a thorough evaluation of dosimetry methods for the measurements of doses remote from the target volume, in phantom experiments. The development of a unified and comprehensive dosimetry methodology for non-target dose estimation is the key element of the WG9 current work. The first scientific aim is to select and review dosimeters suitable for photon and neutron dosimetry in radiotherapy and to evaluate the characteristics of dosimeters at CEA LIST Saclay in reference clinical LINAC beam. (author)

  12. [F-18]-fluorodeoxyglucose positron emission tomography for targeting radiation dose escalation for patients with glioblastoma multiforme: Clinical outcomes and patterns of failure

    International Nuclear Information System (INIS)

    Douglas, James G.; Stelzer, Keith J.; Mankoff, David A.; Tralins, Kevin S.; Krohn, Kenneth A.; Muzi, Mark; Silbergeld, Daniel L.; Rostomily, Robert C.; Scharnhorst, Jeffrey B.S.; Spence, Alexander M.

    2006-01-01

    Purpose: [F-18]-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging for brain tumors has been shown to identify areas of active disease. Radiation dose escalation in the treatment of glioblastoma multiforme may lead to improved disease control. Based on these premises, we initiated a prospective study of FDG-PET for the treatment planning of radiation dose escalation for the treatment of glioblastoma multiforme. Methods and Materials: Forty patients were enrolled. Patients were treated with standard conformal fractionated radiotherapy with volumes defined by MRI imaging. When patients reached a dose of 45-50.4 Gy, they underwent FDG-PET imaging for boost target delineation, for an additional 20 Gy (2 Gy per fraction) to a total dose of 79.4 Gy (n = 30). Results: The estimated 1-year and 2-year overall survival (OS) for the entire group was 70% and 17%, respectively, with a median overall survival of 70 weeks. The estimated 1-year and 2-year progression-free survival (PFS) was 18% and 3%, respectively, with a median of 24 weeks. No significant improvements in OS or PFS were observed for the study group in comparison to institutional historical controls. Conclusions: Radiation dose escalation to 79.4 Gy based on FDG-PET imaging demonstrated no improvement in OS or PFS. This study establishes the feasibility of integrating PET metabolic imaging into radiotherapy treatment planning

  13. Microdistribution of radium 226 in the beagle skeleton and the resulting radiation dose to the target cells

    International Nuclear Information System (INIS)

    Polig, E.; Jee, W.S.S.

    1989-01-01

    The microdistribution of radium 226 in bone sections of beagle dogs, receiving a single injection of 355 or 37 kBq/kg body weight, was analysed by means of a photometric scanning technique. The animals were sacrificed at 5-3000 days post-injection. Time dependence of the concentration of radium 226 was measured in lumbar vertebra and proximal ulnar bones. Hotspot/diffuse ratios, fraction of activity in hotspots and local radiation dose rates to lining cells and hit frequencies to cell nuclei were also determined. Intense irradiation in the high level animals led to abnormal bone formation not observed at the lower level. (author)

  14. Dosimetric evaluation of the impacts of different heterogeneity correction algorithms on target doses in stereotactic body radiation therapy for lung tumors

    International Nuclear Information System (INIS)

    Narabayashi, Masaru; Mizowaki, Takashi; Matsuo, Yukinori; Nakamura, Mitsuhiro; Takayama, Kenji; Norihisa, Yoshiki; Sakanaka, Katsuyuki; Hiraoka, Masahiro

    2012-01-01

    Heterogeneity correction algorithms can have a large impact on the dose distributions of stereotactic body radiation therapy (SBRT) for lung tumors. Treatment plans of 20 patients who underwent SBRT for lung tumors with the prescribed dose of 48 Gy in four fractions at the isocenter were reviewed retrospectively and recalculated with different heterogeneity correction algorithms: the pencil beam convolution algorithm with a Batho power-law correction (BPL) in Eclipse, the radiological path length algorithm (RPL), and the X-ray Voxel Monte Carlo algorithm (XVMC) in iPlan. The doses at the periphery (minimum dose and D95) of the planning target volume (PTV) were compared using the same monitor units among the three heterogeneity correction algorithms, and the monitor units were compared between two methods of dose prescription, that is, an isocenter dose prescription (IC prescription) and dose-volume based prescription (D95 prescription). Mean values of the dose at the periphery of the PTV were significantly lower with XVMC than with BPL using the same monitor units (P<0.001). In addition, under IC prescription using BPL, RPL and XVMC, the ratios of mean values of monitor units were 1, 0.959 and 0.986, respectively. Under D95 prescription, they were 1, 0.937 and 1.088, respectively. These observations indicated that the application of XVMC under D95 prescription results in an increase in the actually delivered dose by 8.8% on average compared with the application of BPL. The appropriateness of switching heterogeneity correction algorithms and dose prescription methods should be carefully validated from a clinical viewpoint. (author)

  15. Labour cost of radiation dose

    International Nuclear Information System (INIS)

    Cook, A.; Lockett, L.E.

    1978-01-01

    In order to optimise capital expenditure on measures to protect workers against radiation it would be useful to have a means to measure radiation dose in money terms. Because labour has to be employed to perform radiation work there must be some relationship between the wages paid and the doses received. Where the next increment of radiation dose requires additional labour to be recruited the cost will at least equal the cost of the extra labour employed. This paper examines some of the factors which affect the variability of the labour cost of radiation dose and notes that for 'in-plant' exposures the current cost per rem appears to be significantly higher than values quoted in ICRP Publication 22. An example is given showing how this concept may be used to determine the capital it is worth spending on installed plant to prevent regular increments of radiation dose to workers. (author)

  16. Modern Radiation Therapy for Nodal Non-Hodgkin Lymphoma—Target Definition and Dose Guidelines From the International Lymphoma Radiation Oncology Group

    DEFF Research Database (Denmark)

    Illidge, Tim; Specht, Lena; Yahalom, Joachim

    2014-01-01

    Radiation therapy (RT) is the most effective single modality for local control of non-Hodgkin lymphoma (NHL) and is an important component of therapy for many patients. Many of the historic concepts of dose and volume have recently been challenged by the advent of modern imaging and RT planning...... tools. The International Lymphoma Radiation Oncology Group (ILROG) has developed these guidelines after multinational meetings and analysis of available evidence. The guidelines represent an agreed consensus view of the ILROG steering committee on the use of RT in NHL in the modern era. The roles...... of reduced volume and reduced doses are addressed, integrating modern imaging with 3-dimensional planning and advanced techniques of RT delivery. In the modern era, in which combined-modality treatment with systemic therapy is appropriate, the previously applied extended-field and involved-field RT...

  17. Intensity modulated radiation therapy (IMRT: differences in target volumes and improvement in clinically relevant doses to small bowel in rectal carcinoma

    Directory of Open Access Journals (Sweden)

    Delclos Marc E

    2011-06-01

    Full Text Available Abstract Background A strong dose-volume relationship exists between the amount of small bowel receiving low- to intermediate-doses of radiation and the rates of acute, severe gastrointestinal toxicity, principally diarrhea. There is considerable interest in the application of highly conformal treatment approaches, such as intensity-modulated radiation therapy (IMRT, to reduce dose to adjacent organs-at-risk in the treatment of carcinoma of the rectum. Therefore, we performed a comprehensive dosimetric evaluation of IMRT compared to 3-dimensional conformal radiation therapy (3DCRT in standard, preoperative treatment for rectal cancer. Methods Using RTOG consensus anorectal contouring guidelines, treatment volumes were generated for ten patients treated preoperatively at our institution for rectal carcinoma, with IMRT plans compared to plans derived from classic anatomic landmarks, as well as 3DCRT plans treating the RTOG consensus volume. The patients were all T3, were node-negative (N = 1 or node-positive (N = 9, and were planned to a total dose of 45-Gy. Pairwise comparisons were made between IMRT and 3DCRT plans with respect to dose-volume histogram parameters. Results IMRT plans had superior PTV coverage, dose homogeneity, and conformality in treatment of the gross disease and at-risk nodal volume, in comparison to 3DCRT. Additionally, in comparison to the 3DCRT plans, IMRT achieved a concomitant reduction in doses to the bowel (small bowel mean dose: 18.6-Gy IMRT versus 25.2-Gy 3DCRT; p = 0.005, bladder (V40Gy: 56.8% IMRT versus 75.4% 3DCRT; p = 0.005, pelvic bones (V40Gy: 47.0% IMRT versus 56.9% 3DCRT; p = 0.005, and femoral heads (V40Gy: 3.4% IMRT versus 9.1% 3DCRT; p = 0.005, with an improvement in absolute volumes of small bowel receiving dose levels known to induce clinically-relevant acute toxicity (small bowel V15Gy: 138-cc IMRT versus 157-cc 3DCRT; p = 0.005. We found that the IMRT treatment volumes were typically larger than that

  18. Analysis of the common deletions in the mitochondrial DNA is a sensitive biomarker detecting direct and non-targeted cellular effects of low dose ionizing radiation

    International Nuclear Information System (INIS)

    Schilling-Toth, Boglarka; Sandor, Nikolett; Kis, Eniko; Kadhim, Munira; Safrany, Geza; Hegyesi, Hargita

    2011-01-01

    One of the key issues of current radiation research is the biological effect of low doses. Unfortunately, low dose science is hampered by the unavailability of easily performable, reliable and sensitive quantitative biomarkers suitable detecting low frequency alterations in irradiated cells. We applied a quantitative real time polymerase chain reaction (qRT-PCR) based protocol detecting common deletions (CD) in the mitochondrial genome to assess direct and non-targeted effects of radiation in human fibroblasts. In directly irradiated (IR) cells CD increased with dose and was higher in radiosensitive cells. Investigating conditioned medium-mediated bystander effects we demonstrated that low and high (0.1 and 2 Gy) doses induced similar levels of bystander responses and found individual differences in human fibroblasts. The bystander response was not related to the radiosensitivity of the cells. The importance of signal sending donor and signal receiving target cells was investigated by placing conditioned medium from a bystander response positive cell line (F11-hTERT) to bystander negative cells (S1-hTERT) and vice versa. The data indicated that signal sending cells are more important in the medium-mediated bystander effect than recipients. Finally, we followed long term effects in immortalized radiation sensitive (S1-hTERT) and normal (F11-hTERT) fibroblasts up to 63 days after IR. In F11-hTERT cells CD level was increased until 35 days after IR then reduced back to control level by day 49. In S1-hTERT cells the increased CD level was also normalized by day 42, however a second wave of increased CD incidence appeared by day 49 which was maintained up to day 63 after IR. This second CD wave might be the indication of radiation-induced instability in the mitochondrial genome of S1-hTERT cells. The data demonstrated that measuring CD in mtDNA by qRT-PCR is a reliable and sensitive biomarker to estimate radiation-induced direct and non-targeted effects.

  19. Analysis of the common deletions in the mitochondrial DNA is a sensitive biomarker detecting direct and non-targeted cellular effects of low dose ionizing radiation.

    Science.gov (United States)

    Schilling-Tóth, Boglárka; Sándor, Nikolett; Kis, Eniko; Kadhim, Munira; Sáfrány, Géza; Hegyesi, Hargita

    2011-11-01

    One of the key issues of current radiation research is the biological effect of low doses. Unfortunately, low dose science is hampered by the unavailability of easily performable, reliable and sensitive quantitative biomarkers suitable detecting low frequency alterations in irradiated cells. We applied a quantitative real time polymerase chain reaction (qRT-PCR) based protocol detecting common deletions (CD) in the mitochondrial genome to assess direct and non-targeted effects of radiation in human fibroblasts. In directly irradiated (IR) cells CD increased with dose and was higher in radiosensitive cells. Investigating conditioned medium-mediated bystander effects we demonstrated that low and high (0.1 and 2Gy) doses induced similar levels of bystander responses and found individual differences in human fibroblasts. The bystander response was not related to the radiosensitivity of the cells. The importance of signal sending donor and signal receiving target cells was investigated by placing conditioned medium from a bystander response positive cell line (F11-hTERT) to bystander negative cells (S1-hTERT) and vice versa. The data indicated that signal sending cells are more important in the medium-mediated bystander effect than recipients. Finally, we followed long term effects in immortalized radiation sensitive (S1-hTERT) and normal (F11-hTERT) fibroblasts up to 63 days after IR. In F11-hTERT cells CD level was increased until 35 days after IR then reduced back to control level by day 49. In S1-hTERT cells the increased CD level was also normalized by day 42, however a second wave of increased CD incidence appeared by day 49 which was maintained up to day 63 after IR. This second CD wave might be the indication of radiation-induced instability in the mitochondrial genome of S1-hTERT cells. The data demonstrated that measuring CD in mtDNA by qRT-PCR is a reliable and sensitive biomarker to estimate radiation-induced direct and non-targeted effects. Copyright

  20. Targeting radiation to tumours

    International Nuclear Information System (INIS)

    Wheldon, T.E.; Greater Glasgow Health Board, Glasgow

    1994-01-01

    Biologically targeted radiotherapy entails the preferential delivery of radiation to solid tumours or individual tumour cells by means of tumour-seeking delivery vehicles to which radionuclides can be conjugated. Monoclonal antibodies have attracted attention for some years as potentially selective targeting agents, but advances in tumour and molecular biology are now providing a much wider choice of molecular species. General radiobiological principles may be derived which are applicable to most forms of targeted radiotherapy. These principles provide guidelines for the appropriate choice of radionuclide in specific treatment situations and its optimal combination with other treatment modalities. In future, the availability of gene targeting agents will focus attention on the use of Auger electron emitters whose high potency and short range selectivity makes them attractive choices for specific killing of cancer cells whose genetic peculiarities are known. (author)

  1. Radiation dose in dental radiology

    International Nuclear Information System (INIS)

    Cohnen, M.; Kemper, J.; Moedder, U.; Moebes, O.; Pawelzik, J.

    2002-01-01

    The aim of this study was to compare radiation exposure in panoramic radiography (PR), dental CT, and digital volume tomography (DVT). An anthropomorphic Alderson-Rando phantom and two anatomical head phantoms with thermoluminescent dosimeters fixed at appropriate locations were exposed as in a dental examination. In PR and DVT, standard parameters were used while variables in CT included mA, pitch, and rotation time. Image noise was assessed in dental CT and DVT. Radiation doses to the skin and internal organs within the primary beam and resulting from scatter radiation were measured and expressed as maximum doses in mGy. For PR, DVT, and CT, these maximum doses were 0.65, 4.2, and 23 mGy. In dose-reduced CT protocols, radiation doses ranged from 10.9 to 6.1 mGy. Effective doses calculated on this basis showed values below 0.1 mSv for PR, DVT, and dose-reduced CT. Image noise was similar in DVT and low-dose CT. As radiation exposure and image noise of DVT is similar to low-dose CT, this imaging technique cannot be recommended as a general alternative to replace PR in dental radiology. (orig.)

  2. Monte Carlo simulation of age-dependent radiation dose from alpha- and beta-emitting radionuclides to critical trabecular bone and bone marrow targets

    Science.gov (United States)

    Dant, James T.; Richardson, Richard B.; Nie, Linda H.

    2013-05-01

    Alpha (α) particles and low-energy beta (β) particles present minimal risk for external exposure. While these particles can induce leukemia and bone cancer due to internal exposure, they can also be beneficial for targeted radiation therapies. In this paper, a trabecular bone model is presented to investigate the radiation dose from bone- and marrow-seeking α and β emitters to different critical compartments (targets) of trabecular bone for different age groups. Two main issues are addressed with Monte Carlo simulations. The first is the absorption fractions (AFs) from bone and marrow to critical targets within the bone for different age groups. The other issue is the application of 223Ra for the radiotherapy treatment of bone metastases. Both a static model and a simulated bone remodeling process are established for trabecular bone. The results show significantly lower AFs from radionuclide sources in the bone volume to the peripheral marrow and the haematopoietic marrow for adults than for newborns and children. The AFs from sources on the bone surface and in the bone marrow to peripheral marrow and haematopoietic marrow also varies for adults and children depending on the energy of the particles. Regarding the use of 223Ra as a radionuclide for the radiotherapy of bone metastases, the simulations show a significantly higher dose from 223Ra and its progeny in forming bone to the target compartment of bone metastases than that from two other more commonly used β-emitting radiopharmaceuticals, 153Sm and 89Sr. There is also a slightly lower dose from 223Ra in forming bone to haematopoietic marrow than that from 153Sm and 89Sr. These results indicate a higher therapy efficiency and lower marrow toxicity from 223Ra and its progeny. In conclusion, age-related changes in bone dimension and cellularity seem to significantly affect the internal dose from α and β emitters in the bone and marrow to critical targets, and 223Ra may be a more efficient

  3. Are low radiation doses Dangerous?

    International Nuclear Information System (INIS)

    Garcia Lima, O.; Cornejo, N.

    1996-01-01

    In the last few years the answers to this questions has been affirmative as well as negative from a radiation protection point of view low doses of ionizing radiation potentially constitute an agent causing stochasting effects. A lineal relation without threshold is assumed between dose and probability of occurrence of these effects . Arguments against the danger of probability of occurrence of these effects. Arguments again the danger of low dose radiation are reflected in concepts such as Hormesis and adaptive response, which are phenomena that being studied at present

  4. ICRU reference dose in an era of intensity-modulated radiation therapy clinical trials: Correlation with planning target volume mean dose and suitability for intensity-modulated radiation therapy dose prescription

    International Nuclear Information System (INIS)

    Yaparpalvi, Ravindra; Hong, Linda; Mah, Dennis; Shen Jin; Mutyala, Subhakar; Spierer, Marnee; Garg, Madhur; Guha, Chandan; Kalnicki, Shalom

    2008-01-01

    Background and Purpose: IMRT clinical trials lack dose prescription and specification standards similar to ICRU standards for two- and three-dimensional external beam planning. In this study, we analyzed dose distributions for patients whose treatment plans incorporated IMRT, and compared the dose determined at the ICRU reference point to the PTV doses determined from dose-volume histograms. Additionally, we evaluated if ICRU reference type single-point dose prescriptions are suitable for IMRT dose prescriptions. Materials and methods: For this study, IMRT plans of 117 patients treated at our institution were randomly selected and analyzed. The treatment plans were clinically applied to the following disease sites: abdominal (11), anal (10), brain (11), gynecological (15), head and neck (25), lung (15), male pelvis (10) and prostate (20). The ICRU reference point was located in each treatment plan following ICRU Report 50 guidelines. The reference point was placed in the central part of the PTV and at or near the isocenter. In each case, the dose was calculated and recorded to this point. For each patient - volume and dose (PTV, PTV mean, median and modal) information was extracted from the planned dose-volume histogram. Results: The ICRU reference dose vs PTV mean dose relationship in IMRT exhibited a weak positive association (Pearson correlation coefficient 0.63). In approximately 65% of the cases studied, dose at the ICRU reference point was greater than the corresponding PTV mean dose. The dose difference between ICRU reference and PTV mean doses was ≤2% in approximately 79% of the cases studied (average 1.21% (±1.55), range -4% to +4%). Paired t-test analyses showed that the ICRU reference doses and PTV median doses were statistically similar (p = 0.42). The magnitude of PTV did not influence the difference between ICRU reference and PTV mean doses. Conclusions: The general relationship between ICRU reference and PTV mean doses in IMRT is similar to that

  5. Prenatal radiation doses from radiopharmaceuticals

    International Nuclear Information System (INIS)

    Rojo, A.M.; Gomez Parada, I.M.; Di Trano, J.L.

    1998-01-01

    The radiopharmaceutical administration with diagnostic or therapeutic purpose during pregnancy implies a prenatal radiation dose. The dose assessment and the evaluation of the radiological risks become relevant due to the great radiosensitivity of the fetal tissues in development. This paper is a revision of the available data for estimating fetal doses in the cases of the more frequently used radiopharmaceuticals in nuclear medicine, taking into account recent investigation in placental crossover. The more frequent diagnostic and therapeutic procedures were analyzed according to the radiation doses implied. (author) [es

  6. Planning magnetic resonance imaging for prostate cancer intensity-modulated radiation therapy: Impact on target volumes, radiotherapy dose and androgen deprivation administration.

    Science.gov (United States)

    Horsley, Patrick J; Aherne, Noel J; Edwards, Grace V; Benjamin, Linus C; Wilcox, Shea W; McLachlan, Craig S; Assareh, Hassan; Welshman, Richard; McKay, Michael J; Shakespeare, Thomas P

    2015-03-01

    Magnetic resonance imaging (MRI) scans are increasingly utilized for radiotherapy planning to contour the primary tumors of patients undergoing intensity-modulated radiation therapy (IMRT). These scans may also demonstrate cancer extent and may affect the treatment plan. We assessed the impact of planning MRI detection of extracapsular extension, seminal vesicle invasion, or adjacent organ invasion on the staging, target volume delineation, doses, and hormonal therapy of patients with prostate cancer undergoing IMRT. The records of 509 consecutive patients with planning MRI scans being treated with IMRT for prostate cancer between January 2010 and July 2012 were retrospectively reviewed. Tumor staging and treatment plans before and after MRI were compared. Of the 509 patients, 103 (20%) were upstaged and 44 (9%) were migrated to a higher risk category as a result of findings at MRI. In 94 of 509 patients (18%), the MRI findings altered management. Ninety-four of 509 patients (18%) had a change to their clinical target volume (CTV) or treatment technique, and in 41 of 509 patients (8%) the duration of hormone therapy was changed because of MRI findings. The use of radiotherapy planning MRI altered CTV design, dose and/or duration of androgen deprivation in 18% of patients in this large, single institution series of men planned for dose-escalated prostate IMRT. This has substantial implications for radiotherapy target volumes and doses, as well as duration of androgen deprivation. Further research is required to investigate whether newer MRI techniques can simultaneously fulfill staging and radiotherapy contouring roles. © 2014 Wiley Publishing Asia Pty Ltd.

  7. Radiation doses in interventional neuroradiology

    International Nuclear Information System (INIS)

    Theodorakou, C.; Butler, P.; Horrocks, J.A.

    2001-01-01

    Patient radiation doses during interventional radiology (IR) procedures may reach the thresholds for radiation-induced skin and eye lens injuries. This study investigates the radiation doses received by patients undergoing cerebral embolization. Measurements were conducted using thermoluminescent dosimeters. Radiotherapy verification films were used in order to visualise the radiation field. For each procedure the fluoroscopic and digital dose-area product, the fluoroscopic time, the total number of acquired images and entrance-skin dose calculated by the angiographic unit were recorded. In this paper, the skin, eye and thyroid glands doses on a sample of patients are presented. From a preliminary study of 13 patients having undergone cerebral embolization, it was deduced that six of them have received a dose above 1 Gy. Detailed dose data from patients undergoing IR procedures will be collected in the future with the aim of developing a model to allow estimation of the dose prior to the procedure as well as to look at techniques of dose reduction. (author)

  8. Radiation dose during angiographic procedures

    International Nuclear Information System (INIS)

    Lavoie, Ch.; Rasuli, P.

    2001-01-01

    The use of angiographic procedures is becoming more prevalent as new techniques and equipment are developed. There have been concerns in the scientific community about the level of radiation doses received by patients, and indirectly by staff, during some of these radiological procedures. The purpose of this study was to assess the level of radiation dose from angiographic procedures to patient at the Ottawa Hospital, General Campus. Radiation dose measurements, using Thermo-Luminescent Dosimeters (TLDs), were performed on more than 100 patients on various procedures. The results show that while the patient dose from the great majority of angiographic procedures is less than 2 Gy, a significant number of procedures, especially interventional procedures may have doses greater than 2 Gy and may lead to deterministic effects. (author)

  9. Radiation apparatus with distance mapper for dose control

    International Nuclear Information System (INIS)

    Saunders, A.M.

    1990-01-01

    The patent describes apparatus for delivering a radiation dose. It comprises: radiation source means for producing a beam of ionizing gamma ray or x-ray radiation directed so as to deliver a dose of the radiation to an area of a target surface, a light source emitting a light beam in a direction transverse to the direction of the ionizing radiation beam, a photodetector, positioned to receive light scattered from the target surface, means for scanning the light beam over the area of the target surface, means for forming a three-dimensional surface profile map of the area of the target surface without movement of the radiation source means or the light source, and means responsive to the surface profile map for adjusting the dose of radiation from the radiation source over the area of the target surface, so that the radiation source means and the light source may be operated simultaneously

  10. Calculating radiation exposure and dose

    International Nuclear Information System (INIS)

    Hondros, J.

    1987-01-01

    This paper discusses the methods and procedures used to calculate the radiation exposures and radiation doses to designated employees of the Olympic Dam Project. Each of the three major exposure pathways are examined. These are: gamma irradiation, radon daughter inhalation and radioactive dust inhalation. A further section presents ICRP methodology for combining individual pathway exposures to give a total dose figure. Computer programs used for calculations and data storage are also presented briefly

  11. Radiation. Doses, effect, risk

    International Nuclear Information System (INIS)

    Vapirev, E.; Todorov, P.

    1994-12-01

    This book outlines in a popular form the topic of ionizing radiation impacts on living organisms. It contains data gathered by ICRP for a period of 35 years. The essential dosimetry terms and units are presented. Natural and artificial sources of ionizing radiation are described. Possible biological radiation effects and diseases as a consequence of external and internal irradiation at normal and accidental conditions are considered. An assessment of genetic risk for human populations is presented and the concept of 'acceptable risk' is discussed

  12. 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

  13. Effects of small radiation doses

    International Nuclear Information System (INIS)

    Fuchs, G.

    1986-01-01

    The term 'small radiation dosis' means doses of about (1 rem), fractions of one rem as well as doses of a few rem. Doses like these are encountered in various practical fields, e.g. in X-ray diagnosis, in the environment and in radiation protection rules. The knowledge about small doses is derived from the same two forces, on which the radiobiology of human beings nearly is based: interpretation of the Hiroshima and Nagasaki data, as well as the experience from radiotherapy. Careful interpretation of Hiroshima dates do not provide any evidence that small doses can induce cancer, fetal malformations or genetic damage. Yet in radiotherapy of various diseases, e.g. inflammations, doses of about 1 Gy (100 rad) do no harm to the patients. According to a widespread hypothesis even very small doses may induce some types of radiation damage ('no threshold'). Nevertheless an alternative view is justified. At present no decision can be made between these two alternatives, but the usefullness of radiology is definitely better established than any damage calculated by theories or extrapolations. Based on experience any exaggerated fear of radiations can be met. (author)

  14. Radiation absorbed doses in cephalography

    International Nuclear Information System (INIS)

    Eliasson, S.; Julin, P.; Richter, S.; Stenstroem, B.

    1984-01-01

    Radiation absorbed doses to different organs in the head and neck region in lateral (LAT) and postero-anterior (PA) cephalography were investigated. The doses were measured by thermoluminescence dosimeters (TLD) on a tissue equivalent phantom head. Lanthanide screens in speed group 4 were used at 90 and 85 k Vp. A near-focus aluminium dodger was used and the radiation beam was collimated strictly to the face. The maximum entrance dose from LAT was 0.25 mGy and 0.42 mGy from a PA exposure. The doses to the salivary glands ranged between 0.2 and 0.02 mGy at LAT and between 0.15 and 0.04 mGy at PA exposures. The average thyroid gland dose without any shielding was 0.11 mGy (LAT) and 0.06 mGy (PA). When a dodger was used the dose was reduced to 0.07 mGy (LAT). If the thyroid gland was sheilded off, the dose was further reduced to 0.01 mGy and if the thyroid region was collimated out of the primary radiation field the dose was reduced to only 0.005 mGy. (authors)

  15. Radiation dose rate measuring device

    International Nuclear Information System (INIS)

    Sorber, R.

    1987-01-01

    A portable device is described for in-field usage for measuring the dose rate of an ambient beta radiation field, comprising: a housing, substantially impervious to beta radiation, defining an ionization chamber and having an opening into the ionization chamber; beta radiation pervious electrically-conductive window means covering the opening and entrapping, within the ionization chamber, a quantity of gaseous molecules adapted to ionize upon impact with beta radiation particles; electrode means disposed within the ionization chamber and having a generally shallow concave surface terminating in a generally annular rim disposed at a substantially close spacing to the window means. It is configured to substantially conform to the window means to define a known beta radiation sensitive volume generally between the window means and the concave surface of the electrode means. The concave surface is effective to substantially fully expose the beta radiation sensitive volume to the radiation field over substantially the full ambient area faced by the window means

  16. Radiation dose rate meter

    International Nuclear Information System (INIS)

    Kronenberg, S.; Siebentritt, C.R.

    1981-01-01

    A combined dose rate meter and charger unit therefor which does not require the use of batteries but on the other hand produces a charging potential by means of a piezoelectric cylinder which is struck by a manually triggered hammer mechanism. A tubular type electrometer is mounted in a portable housing which additionally includes a geiger-muller (Gm) counter tube and electronic circuitry coupled to the electrometer for providing multi-mode operation. In one mode of operation, an rc circuit of predetermined time constant is connected to a storage capacitor which serves as a timed power source for the gm tube, providing a measurement in terms of dose rate which is indicated by the electrometer. In another mode, the electrometer indicates individual counts

  17. Non-targeted effects of ionising radiation

    International Nuclear Information System (INIS)

    Belyakov, O.V.

    2008-01-01

    The universality of the target theory of radiation-induced effects is challenged by observations on non-targeted effects such as bystander effects and genomic instability. Essential features of non-targeted effects are that they do not require direct nuclear exposure by radiation and they are particularly significant at low doses. This new evidence suggests a need for a new paradigm in radiation biology. The new paradigm would cover both the classical (targeted) and the non-targeted effects. New aspects include the role of cellular communication and tissue-level responses. A better understanding of non-targeted effects may have important consequences for health risk assessment and, consequently, on radiation protection. Non-targeted effects may contribute to the estimation of cancer risk from occupational, medical and environmental exposures. In particular, they may have implications for the applicability of the Linear-No-Threshold (LNT) model in extrapolating radiation risk data into the low-dose region. This also means that the adequacy of the concept of dose to estimate risk is challenged by these findings. Moreover, these effects may provide new mechanistic explanations for the development of non-cancer diseases. Further research is required to determine if these effects, typically measured in cell cultures, are applicable in tissue level, whole animals, and ultimately in humans. (orig.)

  18. Spiral CT and radiation dose

    International Nuclear Information System (INIS)

    Imhof, H.; Schibany, N.; Ba-Ssalamah, A.; Czerny, C.; Hojreh, A.; Kainberger, F.; Krestan, C.; Kudler, H.; Noebauer, I.; Nowotny, R.

    2003-01-01

    Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981. Nowadays there are several modifications of the CTDI values, which may lead to confusion. It is suggested to use the standardized CTDI-100 w. value together with the dose length product in all CT-examinations. These values should be printed on all CT-images and allows an evaluation of the individualized patient dose. Nowadays, radiologist's aim must be to work at the lowest maximal diagnostic acceptable signal to noise ratio. To decrease radiation dose radiologist should use low kV and mA, but high pitches. Newly developed CT-dose-reduction soft-wares and filters should be installed in all CT-machines. We should critically compare the average dose used for a specific examination with the reference dose used in this country and/or Europe. Greater differences should caution the radiologist. Finally, we as radiologists must check very carefully all indications and recommend alternative imaging methods. But we have also to teach our customers--patients and medical doctors who are non-radiologists--that a 'good' image is not that which show all possible information, but that which visualize 'only' the diagnostic necessary information

  19. Atmospheric radiation flight dose rates

    Science.gov (United States)

    Tobiska, W. K.

    2015-12-01

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

  20. Circumferential or sectored beam arrangements for stereotactic body radiation therapy (SBRT) of primary lung tumors: Effect on target and normal-structure dose-volume metrics

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Mara W. [Broad Institute of MIT and Harvard, Cambridge, MA (United States); Department of Physics, Brandeis University, Waltham, MA (United States); Kato, Catherine M. [Macalester College, St. Paul, MN (United States); Carson, Kelly M.P. [The University of North Carolina, Chapel Hill, NC (United States); Matsunaga, Nathan M. [Santa Clara University, Santa Clara, CA (United States); Arao, Robert F. [Department of Public Health and Preventive Medicine, Oregon Health and Science University, Portland, OR (United States); Doss, Emily J. [Department of Internal Medicine, Providence St. Vincent Medical Center, Portland, OR (United States); McCracken, Charles L. [Department of Radiation Medicine, Oregon Health and Science University, Portland, OR (United States); Meng, Lu Z. [Department of Radiation Oncology, University of California Davis Comprehensive Cancer Center, Sacramento, CA (United States); Chen, Yiyi [Department of Public Health and Preventive Medicine, Oregon Health and Science University, Portland, OR (United States); Laub, Wolfram U.; Fuss, Martin [Department of Radiation Medicine, Oregon Health and Science University, Portland, OR (United States); Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, Corvallis, OR (United States); Tanyi, James A., E-mail: tanyij@ohsu.edu [Department of Radiation Medicine, Oregon Health and Science University, Portland, OR (United States); Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, Corvallis, OR (United States)

    2013-01-01

    To compare 2 beam arrangements, sectored (beam entry over ipsilateral hemithorax) vs circumferential (beam entry over both ipsilateral and contralateral lungs), for static-gantry intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) delivery techniques with respect to target and organs-at-risk (OAR) dose-volume metrics, as well as treatment delivery efficiency. Data from 60 consecutive patients treated using stereotactic body radiation therapy (SBRT) for primary non–small-cell lung cancer (NSCLC) formed the basis of this study. Four treatment plans were generated per data set: IMRT/VMAT plans using sectored (-s) and circumferential (-c) configurations. The prescribed dose (PD) was 60 Gy in 5 fractions to 95% of the planning target volume (PTV) (maximum PTV dose ∼ 150% PD) for a 6-MV photon beam. Plan conformality, R{sub 50} (ratio of volume circumscribed by the 50% isodose line and the PTV), and D{sub 2} {sub cm} (D{sub max} at a distance ≥2 cm beyond the PTV) were evaluated. For lungs, mean doses (mean lung dose [MLD]) and percent V{sub 30}/V{sub 20}/V{sub 10}/V{sub 5} Gy were assessed. Spinal cord and esophagus D{sub max} and D{sub 5}/D{sub 50} were computed. Chest wall (CW) D{sub max} and absolute V{sub 30}/V{sub 20}/V{sub 10}/V{sub 5} {sub Gy} were reported. Sectored SBRT planning resulted in significant decrease in contralateral MLD and V{sub 10}/V{sub 5} {sub Gy}, as well as contralateral CW D{sub max} and V{sub 10}/V{sub 5} {sub Gy} (all p < 0.001). Nominal reductions of D{sub max} and D{sub 5}/D{sub 50} for the spinal cord with sectored planning did not reach statistical significance for static-gantry IMRT, although VMAT metrics did show a statistically significant decrease (all p < 0.001). The respective measures for esophageal doses were significantly lower with sectored planning (p < 0.001). Despite comparable dose conformality, irrespective of planning configuration, R{sub 50} significantly improved with IMRT

  1. Prenatal radiation exposure. Dose calculation

    International Nuclear Information System (INIS)

    Scharwaechter, C.; Schwartz, C.A.; Haage, P.; Roeser, A.

    2015-01-01

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

  2. Radiation dose monitoring in the clinical routine

    Energy Technology Data Exchange (ETDEWEB)

    Guberina, Nika [UK Essen (Germany). Radiology

    2017-04-15

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

  3. Dose limits for ionising radiation

    International Nuclear Information System (INIS)

    Gifford, D.

    1989-01-01

    Dose limits for exposure to ionising radiation are assessed to see if they give sufficient protection both for the occupationally exposed and for the general public. It is concluded that current limits give a level of safety that satisfies the necessary criteria in the light of present knowledge and further reductions would be unlikely to improve standards of safety. (author)

  4. A Paradigm Shift in Low Dose Radiation Biology

    Directory of Open Access Journals (Sweden)

    Z. Alatas

    2015-08-01

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

  5. Intracavitary radiation treatment planning and dose evaluation

    International Nuclear Information System (INIS)

    Anderson, L.L.; Masterson, M.E.; Nori, D.

    1987-01-01

    Intracavitary radiation therapy with encapsulated radionuclide sources has generally involved, since the advent of afterloading techniques, inserting the sources in tubing previously positioned within a body cavity near the region to be treated. Because of the constraints on source locations relative to the target region, the functions of treatment planning and dose evaluation, usually clearly separable in interstitial brachytherapy, tend to merge in intracavitary therapy. Dose evaluation is typically performed for multiple source-strength configurations in the process of planning and thus may be regarded as complete when a particular configuration has been selected. The input data for each dose evaluation, of course, must include reliable dose distribution information for the source-applicator combinations used. Ultimately, the goal is to discover the source-strength configuration that results in the closest possible approach to the dose distribution desired

  6. Health effect of low dose/low dose rate radiation

    International Nuclear Information System (INIS)

    Kodama, Seiji

    2012-01-01

    The clarified and non-clarified scientific knowledge is discussed to consider the cause of confusion of explanation of the title subject. The low dose is defined roughly lower than 200 mGy and low dose rate, 0.05 mGy/min. The health effect is evaluated from 2 aspects of clinical symptom/radiation hazard protection. In the clinical aspect, the effect is classified in physical (early and late) and genetic ones, and is classified in stochastic (no threshold value, TV) and deterministic (with TV) ones from the radioprotection aspect. Although the absence of TV in the carcinogenic and genetic effects has not been proved, ICRP employs the stochastic standpoint from the safety aspect for radioprotection. The lowest human TV known now is 100 mGy, meaning that human deterministic effect would not be generated below this dose. Genetic deterministic effect can be observable only in animal experiments. These facts suggest that the practical risk of exposure to <100 mGy in human is the carcinogenesis. The relationship between carcinogenic risk in A-bomb survivors and their exposed dose are found fitted to the linear no TV model, but the epidemiologic data, because of restriction of subject number analyzed, do not always mean that the model is applicable even below the dose <100 mGy. This would be one of confusing causes in explanation: no carcinogenic risk at <100 mGy or risk linear to dose even at <100 mGy, neither of which is scientifically conclusive at present. Also mentioned is the scarce risk of cancer in residents living in the high background radiation regions in the world in comparison with that in the A-bomb survivors exposed to the chronic or acute low dose/dose rate. Molecular events are explained for the low-dose radiation-induced DNA damage and its repair, gene mutation and chromosome aberration, hypothesis of carcinogenesis by mutation, and non-targeting effect of radiation (bystander effect and gene instability). Further researches to elucidate the low dose

  7. Natural radiation dose to Gammarus

    International Nuclear Information System (INIS)

    Paschoa, A.S.; Wrenn, M.E.; Eisenbud, M.

    1975-01-01

    The natural radiation dose rate to whole body and components of the Gammarus species (i.e., G. Tigrinus, G. Fasciatus and G. Daiberi) that occurs in the Hudson River is evaluated and the results compared with the upper limits of dose rates from man made sources to the whole body of the organisms. Methods were developed to study the distribution of alpha emitters from 226 Ra plus daughter products in Gammarus using autoradiographic techniques, taking into account the amount of radon that escapes from the organisms. This methodology may be adapted to study the distribution of alpha emitters in contaminated tissues of plants and animals

  8. 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)

  9. Dose escalation of radical radiation therapy in non-small-cell lung cancer using positron emission tomography/computed tomography-defined target volumes: Are class solutions obsolete?

    International Nuclear Information System (INIS)

    Everitt, S.; Schneider-Kolsky, M.; Budd, R.; Yuen, K.; Manus, M Mac

    2008-01-01

    Full text: This study investigated the maximum theoretical radiation dose that could safely be delivered to 20 patients diagnosed with non-small-cell lung cancer. Two three-dimensional conformal radiation therapy (RT) class-solution techniques (A and B) and an individualized three-dimensional conformal RT technique (C) were compared at the standard dose of 60 Gy (part I). Dose escalation was then attempted for each technique successfully at 60 Gy, constrained by predetermined limits for lung and spinal canal (part II). Part I and part II data were reanalysed to include oesophageal dose constraints (part III). In part I, 60 Gy was successfully planned using techniques A, B and C in 19 (95%), 18 (90%) and 20 (100%) patients, respectively. The mean escalated dose attainable for part II using techniques A, B and C were 76.4, 74 and 97.8 Gy, respectively (P < 0.0005). One (5%) patient was successfully planned for 120 Gy using techniques A and B, whereas four (20%) were successfully planned using technique C. Following the inclusion of additional constraints applied to the oesophagus in part III, the amount of escalated dose remained the same for all patients who were successfully planned at 60 Gy apart from two patients when technique C was applied. In conclusion, individualized three-dimensional conformal RT facilitated greater dose conformation and higher escalation of dose in most patients. With modern planning tools, simple class solutions are obsolete for conventional dose radical RT in non-small-cell lung cancer. Highly individualized conformal planning is essential for dose escalation.

  10. Brachytherapy radiation doses to the neurovascular bundles

    International Nuclear Information System (INIS)

    Di Biase, Steven J.; Wallner, Kent; Tralins, Kevin; Sutlief, Steven

    2000-01-01

    Purpose: To investigate the role of radiation dose to the neurovascular bundles (NVB) in brachytherapy-related impotence. Methods and Materials: Fourteen Pd-103 or I-125 implant patients were studied. For patients treated with implant alone, the prostate and margin (clinical target volume [CTV]) received a prescription dose of 144 Gy for I-125 or 115 Gy for Pd-103. Two patients received Pd-103 (90 Gy) with 46 Gy supplemental external beam radiation (EBRT). Axial CT images were acquired 2 to 4 hours postoperatively for postimplant dosimetry. Because the NVBs cannot be visualized on CT, NVB calculation points were determined according to previously published anatomic descriptions. Bilateral NVB points were considered to lie posterior-laterally, approximately 2 mm from the prostatic capsule. NVB doses were recorded bilaterally, at 0.5-cm intervals from the prostatic base. Results: For Pd-103, the average NVB doses ranged from 150 Gy to 260 Gy, or 130% to 226% of the prescription dose. For I-125, the average NVB dose ranged from 200 Gy to 325 Gy, or 140% to 225% of the prescription dose. These was no consistent relationship between the NVB dose and the distance from the prostatic base. To examine the possible effect of minor deviations of our calculation points from the true NVB location, we performed NVB calculations at points 2 mm medial or lateral from the NVB calculation point in 8 patients. Doses at these alternate calculation points were comparable, although there was greater variability with small changes in the calculation point if sources were located outside the capsule, near the NVB calculation point. Three patients who developed early postimplant impotence had maximal NVB doses that far exceeded the average values. Conclusions: In the next few years, we hope to clarify the role of high NVB radiation doses on potency, by correlating NVB dose calculations with a large number of patients enrolled in an ongoing I-125 versus Pd-103 trial for early-stage patients

  11. Radiation doses from residual radioactivity

    International Nuclear Information System (INIS)

    Okajima, Shunzo; Fujita, Shoichiro; Harley, John H.

    1987-01-01

    requires knowing the location of the person to within about 200 m from the time of the explosion to a few weeks afterwards. This is an effort that might be comparable to the present shielding study for survivors. The sizes of the four exposed groups are relatively small; however, the number has been estimated only for those exposed to fallout in the Nishiyama district of Nagasaki. Okajima listed the population of Nishiyama as about 600 at the time of the bomb. No figures are available for the other three groups. The individual exposures from residual radiation may not be significant compared with the direct radiation at the time of the bomb. On the other hand, individuals with potential exposure from these sources are dubious candidates for inclusion in a cohort that was presumably not exposed. For comparison with organ doses estimated in other parts of this program, the exposure estimates are converted to absorbed dose in tissue. The first conversion of exposure to absorbed dose in air uses the factor rad in air 0.87 x exposure in R. UNSCEAR uses an average combined factor of 0.7 to convert absorbed dose in air to absorbed dose in tissue for the whole body. This factor accounts for the change in material (air to tissue) and for backscatter and the shielding afforded by other tissues of the body. No allowance for shielding by buildings has been included here. The cumulative fallout exposures given above become absorbed doses in tissue of 12 to 24 rad for Nagasaki and 0.6 to 2 rad for Hiroshima. The cumulative exposures from induced radioactivity become absorbed doses in tissue of 18 to 24 rad for Nagasaki and about 50 rad for Hiroshima. (author)

  12. Dose-shaping using targeted sparse optimization

    Energy Technology Data Exchange (ETDEWEB)

    Sayre, George A.; Ruan, Dan [Department of Radiation Oncology, University of California - Los Angeles School of Medicine, 200 Medical Plaza, Los Angeles, California 90095 (United States)

    2013-07-15

    Purpose: Dose volume histograms (DVHs) are common tools in radiation therapy treatment planning to characterize plan quality. As statistical metrics, DVHs provide a compact summary of the underlying plan at the cost of losing spatial information: the same or similar dose-volume histograms can arise from substantially different spatial dose maps. This is exactly the reason why physicians and physicists scrutinize dose maps even after they satisfy all DVH endpoints numerically. However, up to this point, little has been done to control spatial phenomena, such as the spatial distribution of hot spots, which has significant clinical implications. To this end, the authors propose a novel objective function that enables a more direct tradeoff between target coverage, organ-sparing, and planning target volume (PTV) homogeneity, and presents our findings from four prostate cases, a pancreas case, and a head-and-neck case to illustrate the advantages and general applicability of our method.Methods: In designing the energy minimization objective (E{sub tot}{sup sparse}), the authors utilized the following robust cost functions: (1) an asymmetric linear well function to allow differential penalties for underdose, relaxation of prescription dose, and overdose in the PTV; (2) a two-piece linear function to heavily penalize high dose and mildly penalize low and intermediate dose in organs-at risk (OARs); and (3) a total variation energy, i.e., the L{sub 1} norm applied to the first-order approximation of the dose gradient in the PTV. By minimizing a weighted sum of these robust costs, general conformity to dose prescription and dose-gradient prescription is achieved while encouraging prescription violations to follow a Laplace distribution. In contrast, conventional quadratic objectives are associated with a Gaussian distribution of violations, which is less forgiving to large violations of prescription than the Laplace distribution. As a result, the proposed objective E{sub tot

  13. Dose-shaping using targeted sparse optimization

    International Nuclear Information System (INIS)

    Sayre, George A.; Ruan, Dan

    2013-01-01

    Purpose: Dose volume histograms (DVHs) are common tools in radiation therapy treatment planning to characterize plan quality. As statistical metrics, DVHs provide a compact summary of the underlying plan at the cost of losing spatial information: the same or similar dose-volume histograms can arise from substantially different spatial dose maps. This is exactly the reason why physicians and physicists scrutinize dose maps even after they satisfy all DVH endpoints numerically. However, up to this point, little has been done to control spatial phenomena, such as the spatial distribution of hot spots, which has significant clinical implications. To this end, the authors propose a novel objective function that enables a more direct tradeoff between target coverage, organ-sparing, and planning target volume (PTV) homogeneity, and presents our findings from four prostate cases, a pancreas case, and a head-and-neck case to illustrate the advantages and general applicability of our method.Methods: In designing the energy minimization objective (E tot sparse ), the authors utilized the following robust cost functions: (1) an asymmetric linear well function to allow differential penalties for underdose, relaxation of prescription dose, and overdose in the PTV; (2) a two-piece linear function to heavily penalize high dose and mildly penalize low and intermediate dose in organs-at risk (OARs); and (3) a total variation energy, i.e., the L 1 norm applied to the first-order approximation of the dose gradient in the PTV. By minimizing a weighted sum of these robust costs, general conformity to dose prescription and dose-gradient prescription is achieved while encouraging prescription violations to follow a Laplace distribution. In contrast, conventional quadratic objectives are associated with a Gaussian distribution of violations, which is less forgiving to large violations of prescription than the Laplace distribution. As a result, the proposed objective E tot sparse improves

  14. Dose-shaping using targeted sparse optimization.

    Science.gov (United States)

    Sayre, George A; Ruan, Dan

    2013-07-01

    Dose volume histograms (DVHs) are common tools in radiation therapy treatment planning to characterize plan quality. As statistical metrics, DVHs provide a compact summary of the underlying plan at the cost of losing spatial information: the same or similar dose-volume histograms can arise from substantially different spatial dose maps. This is exactly the reason why physicians and physicists scrutinize dose maps even after they satisfy all DVH endpoints numerically. However, up to this point, little has been done to control spatial phenomena, such as the spatial distribution of hot spots, which has significant clinical implications. To this end, the authors propose a novel objective function that enables a more direct tradeoff between target coverage, organ-sparing, and planning target volume (PTV) homogeneity, and presents our findings from four prostate cases, a pancreas case, and a head-and-neck case to illustrate the advantages and general applicability of our method. In designing the energy minimization objective (E tot (sparse)), the authors utilized the following robust cost functions: (1) an asymmetric linear well function to allow differential penalties for underdose, relaxation of prescription dose, and overdose in the PTV; (2) a two-piece linear function to heavily penalize high dose and mildly penalize low and intermediate dose in organs-at risk (OARs); and (3) a total variation energy, i.e., the L1 norm applied to the first-order approximation of the dose gradient in the PTV. By minimizing a weighted sum of these robust costs, general conformity to dose prescription and dose-gradient prescription is achieved while encouraging prescription violations to follow a Laplace distribution. In contrast, conventional quadratic objectives are associated with a Gaussian distribution of violations, which is less forgiving to large violations of prescription than the Laplace distribution. As a result, the proposed objective E tot (sparse) improves tradeoff between

  15. Comparison of radiation absorbed dose in target organs in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography and computed tomography

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2009-12-01

    Full Text Available "nBackground and Aim: The objective of this study was to measure and compare the tissue absorbed dose in thyroid gland, salivary glands, eye and skin in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography (CBCT and computed tomography (CT."nMaterials and Methods: Thermoluminescent dosimeters (TLD were implanted in 14 sites of RANDO phantom to measure average tissue absorbed dose in thyroid gland, parotid glands, submandibular glands, sublingual gland, lenses and buccal skin. The Promax (PLANMECA, Helsinki, Finland unit was selected for Panoramic, conventional linear tomography and cone beam computed tomography examinations and spiral Hispeed/Fxi (General Electric,USA was selected for CT examination. The average tissue absorbed doses were used for the calculation of the equivalent and effective doses in each organ."nResults: The average absorbed dose for Panoramic ranged from 0.038 mGY (Buccal skin to 0.308 mGY (submandibular gland, linear tomography ranged from 0.048 mGY (Lens to 0.510 mGY (submandibular gland,CBCT ranged from 0.322 mGY (thyroid glad to 1.144 mGY (Parotid gland and in CT ranged from 2.495 mGY (sublingual gland to 3.424 mGY (submandibular gland. Total effective dose in CBCT is 5 times greater than Panoramic and 4 times greater than linear tomography, and in CT, 30 and 22 times greater than Panoramic and linear tomography, respectively. Total effective dose in CT is 6 times greater than CBCT."nConclusion: For obtaining 3-dimensional (3D information in maxillofacial region, CBCT delivers the lower dose than CT, and should be preferred over a medical CT imaging. Furthermore, during maxillofacial imaging, salivary glands receive the highest dose of radiation.

  16. Effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Masse, R.

    2006-01-01

    Several groups of human have been irradiated by accidental or medical exposure, if no gene defect has been associated to these exposures, some radioinduced cancers interesting several organs are observed among persons exposed over 100 to 200 mSv delivered at high dose rate. Numerous steps are now identified between the initial energy deposit in tissue and the aberrations of cell that lead to tumors but the sequence of events and the specific character of some of them are the subject of controversy. The stake of this controversy is the risk assessment. From the hypothesis called linear relationship without threshold is developed an approach that leads to predict cancers at any tiny dose without real scientific foundation. The nature and the intensity of biological effects depend on the quantity of energy absorbed in tissue and the modality of its distribution in space and time. The probability to reach a target (a gene) associated to the cancerating of tissue is directly proportional to the dose without any other threshold than the quantity of energy necessary to the effect, its probability of effect can be a more complex function and depends on the quality of the damage produced as well as the ability of the cell to repair the damage. These two parameters are influenced by the concentration of initial injuries in the target so by the quality of radiation and by the dose rate. The mechanisms of defence explain the low efficiency of radiation as carcinogen and then the linearity of effects in the area of low doses is certainly the least defensible scientific hypothesis for the prediction of the risks. (N.C.)

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

    African Journals Online (AJOL)

    Enrique

    SA JOURNAL OF RADIOLOGY • August 2004. Abstract. This study determined the correlation between radiation doses absorbed by health care workers and dose area product meter (DAP) measurements at Universitas Hospital, Bloemfontein. The DAP is an instrument which accurately measures the radiation emitted from ...

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

    African Journals Online (AJOL)

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

  19. Fast neutron dose equivalent rates in heavy ion target areas

    International Nuclear Information System (INIS)

    Fulmer, C.B.; Butler, H.M.; Ohnesorge, W.F.; Mosko, S.W.

    1978-01-01

    At heavy ion accelerators, personnel access to areas near the target is sometimes important for successful performance of experiments. Radiation levels determine the amount of time that can be spent in these areas without exceeding maximum permissible exposures. Inasmuch as the fast neutrons contribute the major part of the Rem dose rates in these areas, knowledge of the fast neutron levels is important for planning permissive entry to target areas. Fast neutron dose rates were measured near thick medium mass targets bombarded with beams of C, N, O, and Ne ions. beam energies ranged from 3 to 16 MeV/amu. Dose rates (mrem/h) 1 meter from the target 90 degrees from the beam direction range from approx. 0.05 at MeV/amu to approx. 50 at 16 MeV/amu. These data should be helpful in planning permissive entry to heavy ion target areas

  20. Fast neutron dose equivalent rates in heavy ion target areas

    Energy Technology Data Exchange (ETDEWEB)

    Fulmer, C.B.; Butler, H.M.; Ohnesorge, W.F.; Mosko, S.W.

    1978-01-01

    At heavy ion accelerators, personnel access to areas near the target is sometimes important for successful performance of experiments. Radiation levels determine the amount of time that can be spent in these areas without exceeding maximum permissible exposures. Inasmuch as the fast neutrons contribute the major part of the Rem dose rates in these areas, knowledge of the fast neutron levels is important for planning permissive entry to target areas. Fast neutron dose rates were measured near thick medium mass targets bombarded with beams of C, N, O, and Ne ions. beam energies ranged from 3 to 16 MeV/amu. Dose rates (mrem/h) 1 meter from the target 90 degrees from the beam direction range from approx. 0.05 at MeV/amu to approx. 50 at 16 MeV/amu. These data should be helpful in planning permissive entry to heavy ion target areas.

  1. Dose reconstruction modeling for medical radiation workers

    International Nuclear Information System (INIS)

    Choi, Yeong Chull; Cha, Eun Shil; Lee, Won Jin

    2017-01-01

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

  2. Dose reconstruction modeling for medical radiation workers

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-04-15

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

  3. Fiber optics in high dose radiation fields

    International Nuclear Information System (INIS)

    Partin, J.K.

    1985-01-01

    A review of the behavior of state-of-the-art optical fiber waveguides in high dose (greater than or equal to 10 5 rad), steady state radiation fields is presented. The influence on radiation-induced transmission loss due to experimental parameters such as dose rate, total dose, irradiation history, temperature, wavelength, and light intensity, for future work in high dose environments are given

  4. Energies, health, medicine. Low radiation doses

    International Nuclear Information System (INIS)

    2004-01-01

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

  5. Radiation effects of high and low doses

    International Nuclear Information System (INIS)

    El-Naggar, A.M.

    1998-01-01

    The extensive proliferation of the uses and applications of atomic and nuclear energy resulted in possible repercussions on human health. The prominent features of the health hazards that may be incurred after exposure to high and low radiation doses are discussed. The physical and biological factors involved in the sequential development of radiation health effects and the different cellular responses to radiation injury are considered. The main criteria and features of radiation effects of high and low doses are comprehensively outlined

  6. Radiation research contracts: Biological effects of small radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Hug, O [International Atomic Energy Agency, Division of Health, Safety and Waste Disposal, Vienna (Austria)

    1959-04-15

    To establish the maximum permissible radiation doses for occupational and other kinds of radiation exposure, it is necessary to know those biological effects which can be produced by very small radiation doses. This particular field of radiation biology has not yet been sufficiently explored. This holds true for possible delayed damage after occupational radiation exposure over a period of many years as well as for acute reactions of the organism to single low level exposures. We know that irradiation of less than 25 Roentgen units (r) is unlikely to produce symptoms of radiation sickness. We have, however, found indications that even smaller doses may produce certain instantaneous reactions which must not be neglected

  7. Studies of Non-Targeted Effects of Ionising Radiation

    International Nuclear Information System (INIS)

    Oleg V Belyakov; Heli Mononen; Marjo Peraelae

    2006-01-01

    The discovery of ionising radiation induced non-targeted effects is important for understanding the dose-response mechanisms relevant to low dose irradiation in vivo. One important question is whether the non-targeted effects relates to a protective mechanism or whether, conversely, it amplifies the number of cells damaged by the isolated radiation tracks of low dose exposures leading to an increased risk of carcinogenesis. One theory supported by the experimental data obtained during this project is that the main functions of the non-targeted effects are to decrease the risk of transformation in a multicellular organism exposed to radiation. Differences in the gene expression profiles, temporal and spatial patterns of key proteins expressed in directly irradiated and bystander cells may determine how the cells ultimately respond to low doses of radiation. Such a mechanism of co-operative response would make the tissue system much more robust. (N.C.)

  8. Studies of Non-Targeted Effects of Ionising Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Oleg V Belyakov; Heli Mononen; Marjo Peraelae [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland)

    2006-07-01

    The discovery of ionising radiation induced non-targeted effects is important for understanding the dose-response mechanisms relevant to low dose irradiation in vivo. One important question is whether the non-targeted effects relates to a protective mechanism or whether, conversely, it amplifies the number of cells damaged by the isolated radiation tracks of low dose exposures leading to an increased risk of carcinogenesis. One theory supported by the experimental data obtained during this project is that the main functions of the non-targeted effects are to decrease the risk of transformation in a multicellular organism exposed to radiation. Differences in the gene expression profiles, temporal and spatial patterns of key proteins expressed in directly irradiated and bystander cells may determine how the cells ultimately respond to low doses of radiation. Such a mechanism of co-operative response would make the tissue system much more robust. (N.C.)

  9. Carcinogenesis induced by low-dose radiation

    Directory of Open Access Journals (Sweden)

    Piotrowski Igor

    2017-11-01

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

  10. Annual radiation dose in thermoluminescence dating

    International Nuclear Information System (INIS)

    Li Huhou

    1988-01-01

    The annual radiation dose in thermoluminescence dating has been discussed. The autor gives an entirely new concept of the enviromental radiation in the thermoluminescence dating. Methods of annual dose detemination used by author are dating. Methods of annual dose determination used by author are summed up, and the results of different methods are compared. The emanium escapiug of three radioactive decay serieses in nature has been considered, and several determination methods are described. The contribution of cosmic rays for the annual radiation dose has been mentioned

  11. Annual radiation dose in thermoluminescence dating

    Energy Technology Data Exchange (ETDEWEB)

    Huhou, Li [Chinese Academy of Social Sciences, Beijing, BJ (China). Inst. of Archaeology

    1988-11-01

    The annual radiation dose in thermoluminescence dating has been discussed. The autor gives an entirely new concept of the enviromental radiation in the thermoluminescence dating. Methods of annual dose detemination used by author are dating. Methods of annual dose determination used by author are summed up, and the results of different methods are compared. The emanium escapiug of three radioactive decay serieses in nature has been considered, and several determination methods are described. The contribution of cosmic rays for the annual radiation dose has been mentioned.

  12. Potential radiation doses from 1994 Hanford Operations

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-06-01

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

  13. Potential radiation doses from 1994 Hanford Operations

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  14. Targeted drugs in radiation therapy

    International Nuclear Information System (INIS)

    Favaudon, V.; Hennequin, C.; Hennequin, C.

    2004-01-01

    New drugs aiming at the development of targeted therapies have been assayed in combination with ionizing radiation over the past few years. The rationale of this concept comes from the fact that the cytotoxic potential of targeted drugs is limited, thus requiring concomitant association with a cytotoxic agent for the eradication of tumor cells. Conversely a low level of cumulative toxicity is expected from targeted drugs. Most targeted drugs act through inhibition of post-translational modifications of proteins, such as dimerization of growth factor receptors, prenylation reactions, or phosphorylation of tyrosine or serine-threonine residues. Many systems involving the proteasome, neo-angiogenesis promoters, TGF-β, cyclooxygenase or the transcription factor NF-κB, are currently under investigation in hopes they will allow a control of cell proliferation, apoptosis, cell cycle progression, tumor angiogenesis and inflammation. A few drugs have demonstrated an antitumor potential in particular phenotypes. In most instances, however, radiation-drug interactions proved to be strictly additive in terms of cell growth inhibition or induced cell death. Strong potentiation of the response to radiotherapy is expected to require interaction with DNA repair mechanisms. (authors)

  15. Cytogenetic effects of low-dose radiation

    International Nuclear Information System (INIS)

    Metalli, P.

    1983-01-01

    The effects of ionizing radiation on chromosomes have been known for several decades and dose-effect relationships are also fairly well established in the mid- and high-dose and dose-rate range for chromosomes of mammalian cells. In the range of low doses and dose rates of different types of radiation few data are available for direct analysis of the dose-effect relationships, and extrapolation from high to low doses is still the unavoidable approach in many cases of interest for risk assessment. A review is presented of the data actually available and of the attempts that have been made to obtain possible generalizations. Attention is focused on some specific chromosomal anomalies experimentally induced by radiation (such as reciprocal translocations and aneuploidies in germinal cells) and on their relevance for the human situation. (author)

  16. Charpak, Garwin, propose unit for radiation dose

    CERN Multimedia

    Feder, Toni

    2002-01-01

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

  17. SMART, Radiation Dose Rates on Cask Surface

    International Nuclear Information System (INIS)

    Yamakoshi, Hisao

    1989-01-01

    1 - Description of program or function: SMART calculates radiation dose rate at the center of each cask surface by using characteristic functions for radiation shielding ability and for radiation current back-scattered from cask wall and cask cavity of each cask, once cask-type is specified. 2 - Method of solution: Matrix Calculation

  18. Low doses effects and gamma radiations low dose rates

    International Nuclear Information System (INIS)

    Averbeck, D.

    1999-01-01

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

  19. Occupational radiation doses during interventional procedures

    International Nuclear Information System (INIS)

    Nuraeni, N; Hiswara, E; Kartikasari, D; Waris, A; Haryanto, F

    2016-01-01

    Digital subtraction angiography (DSA) is a type of fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. The use of DSA procedures has been increased quite significantly in the Radiology departments in various cities in Indonesia. Various reports showed that both patients and medical staff received a noticeable radiation dose during the course of this procedure. A study had been carried out to measure these doses among interventionalist, nurse and radiographer. The results show that the interventionalist and the nurse, who stood quite close to the X-ray beams compared with the radiographer, received radiation higher than the others. The results also showed that the radiation dose received by medical staff were var depending upon the duration and their position against the X-ray beams. Compared tothe dose limits, however, the radiation dose received by all these three medical staff were still lower than the limits. (paper)

  20. Dose evaluation and protection of cosmic radiation

    International Nuclear Information System (INIS)

    Iwai, Satoshi; Takagi, Toshiharu

    2004-01-01

    This paper explained the effects of cosmic radiation on aircraft crews and astronauts, as well as related regulations. International Commission on Radiological Protection (ICRP) recommends the practice of radiation exposure management for the handling/storage of radon and materials containing natural radioactive substances, as well as for boarding jet aircraft and space flight. Common aircraft crew members are not subject to radiation exposure management in the USA and Japan. In the EU, the limit value is 6 mSv per year, and for the crew group exceeding this value, it is recommended to keep records containing appropriate medical examination results. Pregnant female crewmembers are required to keep an abdominal surface dose within 1 mSv. For astronauts, ICRP is in the stage of thinking about exposure management. In the USA, National Council on Radiation Protection and Measurement has set dose limits for 30 days, 1 year, and lifetime, and recommends lifetime effective dose limits against carcinogenic risk for each gender and age group. This is the setting of the dose limits so that the risk of carcinogenesis, to which space radiation exposure is considered to contribute, will reach 3%. For cosmic radiation environments at spacecraft inside and aircraft altitude, radiation doses can be calculated for astronauts and crew members, using the calculation methods for effective dose and dose equivalent for tissue. (A.O.)

  1. Computing proton dose to irregularly moving targets

    International Nuclear Information System (INIS)

    Phillips, Justin; Gueorguiev, Gueorgui; Grassberger, Clemens; Dowdell, Stephen; Paganetti, Harald; Sharp, Gregory C; Shackleford, James A

    2014-01-01

    Purpose: While four-dimensional computed tomography (4DCT) and deformable registration can be used to assess the dose delivered to regularly moving targets, there are few methods available for irregularly moving targets. 4DCT captures an idealized waveform, but human respiration during treatment is characterized by gradual baseline shifts and other deviations from a periodic signal. This paper describes a method for computing the dose delivered to irregularly moving targets based on 1D or 3D waveforms captured at the time of delivery. Methods: The procedure uses CT or 4DCT images for dose calculation, and 1D or 3D respiratory waveforms of the target position at time of delivery. Dose volumes are converted from their Cartesian geometry into a beam-specific radiological depth space, parameterized in 2D by the beam aperture, and longitudinally by the radiological depth. In this new frame of reference, the proton doses are translated according to the motion found in the 1D or 3D trajectory. These translated dose volumes are weighted and summed, then transformed back into Cartesian space, yielding an estimate of the dose that includes the effect of the measured breathing motion. The method was validated using a synthetic lung phantom and a single representative patient CT. Simulated 4DCT was generated for the phantom with 2 cm peak-to-peak motion. Results: A passively-scattered proton treatment plan was generated using 6 mm and 5 mm smearing for the phantom and patient plans, respectively. The method was tested without motion, and with two simulated breathing signals: a 2 cm amplitude sinusoid, and a 2 cm amplitude sinusoid with 3 cm linear drift in the phantom. The tumor positions were equally weighted for the patient calculation. Motion-corrected dose was computed based on the mid-ventilation CT image in the phantom and the peak exhale position in the patient. Gamma evaluation was 97.8% without motion, 95.7% for 2 cm sinusoidal motion, 95.7% with 3 cm drift in

  2. Dose Assurance in Radiation Processing Plants

    DEFF Research Database (Denmark)

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

    1983-01-01

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

  3. Reducing dose to the lungs through loosing target dose homogeneity requirement for radiotherapy of non small cell lung cancer.

    Science.gov (United States)

    Miao, Junjie; Yan, Hui; Tian, Yuan; Ma, Pan; Liu, Zhiqiang; Li, Minghui; Ren, Wenting; Chen, Jiayun; Zhang, Ye; Dai, Jianrong

    2017-11-01

    It is important to minimize lung dose during intensity-modulated radiation therapy (IMRT) of nonsmall cell lung cancer (NSCLC). In this study, an approach was proposed to reduce lung dose by relaxing the constraint of target dose homogeneity during treatment planning of IMRT. Ten NSCLC patients with lung tumor on the right side were selected. The total dose for planning target volume (PTV) was 60 Gy (2 Gy/fraction). For each patient, two IMRT plans with six beams were created in Pinnacle treatment planning system. The dose homogeneity of target was controlled by constraints on the maximum and uniform doses of target volume. One IMRT plan was made with homogeneous target dose (the resulting target dose was within 95%-107% of the prescribed dose), while another IMRT plan was made with inhomogeneous target dose (the resulting target dose was more than 95% of the prescribed dose). During plan optimization, the dose of cord and heart in two types of IMRT plans were kept nearly the same. The doses of lungs, PTV and organs at risk (OARs) between two types of IMRT plans were compared and analyzed quantitatively. For all patients, the lung dose was decreased in the IMRT plans with inhomogeneous target dose. On average, the mean dose, V5, V20, and V30 of lung were reduced by 1.4 Gy, 4.8%, 3.7%, and 1.7%, respectively, and the dose to normal tissue was also reduced. These reductions in DVH values were all statistically significant (P target dose could protect lungs better and may be considered as a choice for treating NSCLC. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  4. Exposure to low doses of ionizing radiations

    International Nuclear Information System (INIS)

    Le Guen, B.

    2008-01-01

    The author discusses the knowledge about the effects of ionizing radiations on mankind. Some of them have been well documented (skin cancer and leukaemia for the pioneer scientists who worked on radiations, some other types of cancer for workers who handled luminescent paints, rock miners, nuclear explosion survivors, patients submitted to radiological treatments). He also evokes the issue of hereditary cancers, and discusses the issue of low dose irradiation where some surveys can now be performed on workers. He discusses the biological effects of these low doses. He outlines that many questions remain about these effects, notably the influence of dose level and of dose rate level on the biological reaction

  5. Development of radiation dose assessment system for radiation accident (RADARAC)

    International Nuclear Information System (INIS)

    Takahashi, Fumiaki; Shigemori, Yuji; Seki, Akiyuki

    2009-07-01

    The possibility of radiation accident is very rare, but cannot be regarded as zero. Medical treatments are quite essential for a heavily exposed person in an occurrence of a radiation accident. Radiation dose distribution in a human body is useful information to carry out effectively the medical treatments. A radiation transport calculation utilizing the Monte Carlo method has an advantageous in the analysis of radiation dose inside of the body, which cannot be measured. An input file, which describes models for the accident condition and quantities of interest, should be prepared to execute the radiation transport calculation. Since the accident situation, however, cannot be prospected, many complicated procedures are needed to make effectively the input file soon after the occurrence of the accident. In addition, the calculated doses are to be given in output files, which usually include much information concerning the radiation transport calculation. Thus, Radiation Dose Assessment system for Radiation Accident (RADARAC) was developed to derive effectively radiation dose by using the MCNPX or MCNP code. RADARAC mainly consists of two parts. One part is RADARAC - INPUT, which involves three programs. A user can interactively set up necessary resources to make input files for the codes, with graphical user interfaces in a personnel computer. The input file includes information concerning the geometric structure of the radiation source and the exposed person, emission of radiations during the accident, physical quantities of interest and so on. The other part is RADARAC - DOSE, which has one program. The results of radiation doses can be effectively indicated with numerical tables, graphs and color figures visibly depicting dose distribution by using this program. These results are obtained from the outputs of the radiation transport calculations. It is confirmed that the system can effectively make input files with a few thousand lines and indicate more than 20

  6. Effective dose: a radiation protection quantity

    CERN Document Server

    Menzel, H G

    2012-01-01

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

  7. Radiation dose to the global flying population

    International Nuclear Information System (INIS)

    Alvarez, Luis E; Eastham, Sebastian D; Barrett, Steven R H

    2016-01-01

    Civil airliner passengers and crew are exposed to elevated levels of radiation relative to being at sea level. Previous studies have assessed the radiation dose received in particular cases or for cohort studies. Here we present the first estimate of the total radiation dose received by the worldwide civilian flying population. We simulated flights globally from 2000 to 2013 using schedule data, applying a radiation propagation code to estimate the dose associated with each flight. Passengers flying in Europe and North America exceed the International Commission on Radiological Protection annual dose limits at an annual average of 510 or 420 flight hours per year, respectively. However, this falls to 160 or 120 h on specific routes under maximum exposure conditions. (paper)

  8. Attenuation measurements show that the presence of a TachoSil surgical patch will not compromise target irradiation in intra-operative electron radiation therapy or high-dose-rate brachytherapy.

    Science.gov (United States)

    Sarmento, Sandra; Costa, Filipa; Pereira, Alexandre; Lencart, Joana; Dias, Anabela; Cunha, Luís; Sousa, Olga; Silva, José Pedro; Santos, Lúcio

    2015-01-09

    Surgery of locally advanced and/or recurrent rectal cancer can be complemented with intra-operative electron radiation therapy (IOERT) to deliver a single dose of radiation directly to the unresectable margins, while sparing nearby sensitive organs/structures. Haemorrhages may occur and can affect the dose distribution, leading to an incorrect target irradiation. The TachoSil (TS) surgical patch, when activated, creates a fibrin clot at the surgical site to achieve haemostasis. The aim of this work was to determine the effect of TS on the dose distribution, and ascertain whether it could be used in combination with IOERT. This characterization was extended to include high dose rate (HDR) intraoperative brachytherapy, which is sometimes used at other institutions instead of IOERT. CT images of the TS patch were acquired for initial characterization. Dosimetric measurements were performed in a water tank phantom, using a conventional LINAC with a hard-docking system of cylindrical applicators. Percentage Depth Dose (PDD) curves were obtained, and measurements made at the depth of dose maximum for the three clinically used electron energies (6, 9 and 12MeV), first without any attenuator and then with the activated patch of TS completely covering the tip of the IOERT applicator. For HDR brachytherapy, a measurement setup was improvised using a solid water phantom and a Farmer ionization chamber. Our measurements show that the attenuation of a TachoSil patch is negligible, both for high energy electron beams (6 to 12MeV), and for a HDR (192)Ir brachytherapy source. Our results cannot be extrapolated to lower beam energies such as 50 kVp X-rays, which are sometimes used for breast IORT. The TachoSil surgical patch can be used in IORT procedures using 6MeV electron energies or higher, or HDR (192)Ir brachytherapy.

  9. Attenuation measurements show that the presence of a TachoSil surgical patch will not compromise target irradiation in intra-operative electron radiation therapy or high-dose-rate brachytherapy

    International Nuclear Information System (INIS)

    Sarmento, Sandra; Costa, Filipa; Pereira, Alexandre; Lencart, Joana; Dias, Anabela; Cunha, Luís; Sousa, Olga; Silva, José Pedro; Santos, Lúcio

    2015-01-01

    Surgery of locally advanced and/or recurrent rectal cancer can be complemented with intra-operative electron radiation therapy (IOERT) to deliver a single dose of radiation directly to the unresectable margins, while sparing nearby sensitive organs/structures. Haemorrhages may occur and can affect the dose distribution, leading to an incorrect target irradiation. The TachoSil (TS) surgical patch, when activated, creates a fibrin clot at the surgical site to achieve haemostasis. The aim of this work was to determine the effect of TS on the dose distribution, and ascertain whether it could be used in combination with IOERT. This characterization was extended to include high dose rate (HDR) intraoperative brachytherapy, which is sometimes used at other institutions instead of IOERT. CT images of the TS patch were acquired for initial characterization. Dosimetric measurements were performed in a water tank phantom, using a conventional LINAC with a hard-docking system of cylindrical applicators. Percentage Depth Dose (PDD) curves were obtained, and measurements made at the depth of dose maximum for the three clinically used electron energies (6, 9 and 12MeV), first without any attenuator and then with the activated patch of TS completely covering the tip of the IOERT applicator. For HDR brachytherapy, a measurement setup was improvised using a solid water phantom and a Farmer ionization chamber. Our measurements show that the attenuation of a TachoSil patch is negligible, both for high energy electron beams (6 to 12MeV), and for a HDR 192 Ir brachytherapy source. Our results cannot be extrapolated to lower beam energies such as 50 kVp X-rays, which are sometimes used for breast IORT. The TachoSil surgical patch can be used in IORT procedures using 6MeV electron energies or higher, or HDR 192 Ir brachytherapy

  10. Radiation Dose Measurement Using Chemical Dosimeters

    International Nuclear Information System (INIS)

    Lee, Min Sun; Kim, Eun Hee; Kim, Yu Ri; Han, Bum Soo

    2010-01-01

    The radiation dose can be estimated in various ways. Dose estimates can be obtained by either experiment or theoretical analysis. In experiments, radiation impact is assessed by measuring any change caused by energy deposition to the exposed matter, in terms of energy state (physical change), chemical production (chemical change) or biological abnormality (biological change). The chemical dosimetry is based on the implication that the energy deposited to the matter can be inferred from the consequential change in chemical production. The chemical dosimetry usually works on the sample that is an aqueous solution, a biological matter, or an organic substance. In this study, we estimated absorbed doses by quantitating chemical changes in matter caused by radiation exposure. Two different chemical dosimeters, Fricke and ECB (Ethanol-Chlorobenzene) dosimeter, were compared in several features including efficacy as dose indicator and effective dose range

  11. Radiation dose assessment in nuclear medicine

    International Nuclear Information System (INIS)

    Stabin, M.G.

    2002-01-01

    In any application involving the use of ionizing radiation in humans, risks and benefits must be properly evaluated and balanced. Radionuclides are used in nuclear medicine in a variety of diagnostic and therapeutic procedures. Recently, interest has grown in therapeutic agents for a number of applications in nuclear medicine, particularly in the treatment of hematologic and non-hematologic malignancies. This has heightened interest in the need for radiation dose calculations and challenged the scientific community to develop more patient-specific and relevant dose models. Consideration of radiation dose in such studies is central to efforts to maximize dose to tumor while sparing normal tissues. In many applications, a significant absorbed dose may be received by some radiosensitive organs, particularly the active marrow. This talk will review the methods and models used in internal dosimetry in nuclear medicine, and discuss some current trends and challenges in this field

  12. Plastic for indicating a radiation dose

    International Nuclear Information System (INIS)

    Hori, Y.; Yoshikawa, N.; Ohmori, S.

    1975-01-01

    A plastic film suitable for indicating radiation dose contains a chlorine polymer, at least one acid sensitive coloring agent and a plasticizer. The film undergoes a distinct change of color in response to a given radiation dose, the degree of change proportional to the total change. These films may be stored for a long period without loss of sensitivity, and have good color stability after irradiation. (auth)

  13. Gamma Radiation Doses In Sweden

    International Nuclear Information System (INIS)

    Almgren, Sara; Isaksson, Mats; Barregaard, Lars

    2008-01-01

    Gamma dose rate measurements were performed in one urban and one rural area using thermoluminescence dosimeters (TLD) worn by 46 participants and placed in their dwellings. The personal effective dose rates were 0.096±0.019(1 SD) and 0.092±0.016(1 SD)μSv/h in the urban and rural area, respectively. The corresponding dose rates in the dwellings were 0.11±0.042(1 SD) and 0.091±0.026(1 SD)μSv/h. However, the differences between the areas were not significant. The values were higher in buildings made of concrete than of wood and higher in apartments than in detached houses. Also, 222 Rn measurements were performed in each dwelling, which showed no correlation with the gamma dose rates in the dwellings

  14. Characteristics of natural background external radiation and effective dose equivalent

    International Nuclear Information System (INIS)

    Fujimoto, Kenzo

    1989-01-01

    The two sources of natural radiation - cosmic rays and primordial radionuclides - are described. The factors affecting radiation doses received from natural radiation and the calculation of effective dose equivalent due to natural radiation are discussed. 10 figs., 3 tabs

  15. Low doses of gamma radiation in soybean

    International Nuclear Information System (INIS)

    Franco, José G.; Franco, Suely S.H.; Villavicencio, Anna L.C.; Arthur, Valter; Arthur, Paula B.; Franco, Caio H.

    2017-01-01

    The degree of radiosensitivity depends mostly on the species, the stage of the embryo at irradiation, the doses employed and the criteria used to measure the effect. One of the most common criteria to evaluate radiosensitivity in seeds is to measure the average plant production. Dry soya seeds were exposed to low doses of gamma radiation from source of Cobalt-60, type Gammecell-220, at 0.210 kGy dose rate. In order to study stimulation effects of radiation on germination, plant growth and production. A treatment with four radiation doses was applied as follows: 0 (control); 12.5; 25.0 and 50.0 Gy. Seed germination and harvested of number of seeds and total production were assessed to identify occurrence of stimulation. Soya seeds number and plants were handled as for usual seed production in Brazil. The low doses of gamma radiation in the seeds that stimulate the production were the doses of 12.5 and 50.0 Gy. The results show that the use of low doses of gamma radiation can stimulate germination and plant production. (author)

  16. Low doses of gamma radiation in soybean

    Energy Technology Data Exchange (ETDEWEB)

    Franco, José G.; Franco, Suely S.H.; Villavicencio, Anna L.C., E-mail: zegilmar60@gmail.com, E-mail: gilmita@uol.com.br, E-mail: villavic@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Arthur, Valter; Arthur, Paula B., E-mail: arthur@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Franco, Caio H. [Universidade Federal de São Paulo (UNIFESP), SP (Brazil). Departamento de Microbiologia, Imunologia e Parasitologia

    2017-07-01

    The degree of radiosensitivity depends mostly on the species, the stage of the embryo at irradiation, the doses employed and the criteria used to measure the effect. One of the most common criteria to evaluate radiosensitivity in seeds is to measure the average plant production. Dry soya seeds were exposed to low doses of gamma radiation from source of Cobalt-60, type Gammecell-220, at 0.210 kGy dose rate. In order to study stimulation effects of radiation on germination, plant growth and production. A treatment with four radiation doses was applied as follows: 0 (control); 12.5; 25.0 and 50.0 Gy. Seed germination and harvested of number of seeds and total production were assessed to identify occurrence of stimulation. Soya seeds number and plants were handled as for usual seed production in Brazil. The low doses of gamma radiation in the seeds that stimulate the production were the doses of 12.5 and 50.0 Gy. The results show that the use of low doses of gamma radiation can stimulate germination and plant production. (author)

  17. Evaluation of radiation doses from radioactive drugs

    International Nuclear Information System (INIS)

    Halperin, J.A.; Grove, G.R.

    1977-01-01

    Radioactive new drugs are regulated by the Food and Drug Administration (FDA) in the United States. Before a new drug can be marketed it must have an approved New Drug Application (NDA). Clinical investigations of a radioactive new drug are carried out under a Notice of Claimed Investigational Exemption for a New Drug (IND), submitted to the FDA. In the review of the IND, radiation doses are projected on the basis of experimental data from animal models and from calculations based upon radiation characteristics, predicted biodistribution of the drug in humans, and activity to be administered. FDA physicians review anticipated doses and prevent clinical investigations in humans when the potential risk of the use of a radioactive substance outweighs the prospect of achieving beneficial results from the administration of the drug. In the evaluation of an NDA, FDA staff attempt to assure that the intended diagnostic or therapeutic effect is achievable with the lowest practicable radiation dose. Radiation doses from radioactive new drugs are evaluated by physicians within the FDA. Important radioactive new drugs are also evaluated by the Radiopharmaceuticals Advisory Committee. FDA also supports the Center for Internal Radiation Dosimetry at Oak Ridge, to provide information regarding in vivo distribution and dosimetry to critical organs and the whole body from radioactive new drugs. The process for evaluation of radiation doses from radioactive new drugs for protection against use of unnecessary radiation exposure by patients in nuclear medicine procedures, a

  18. Radiation doses - maps and magnitudes

    International Nuclear Information System (INIS)

    1989-01-01

    A NRPB leaflet in the 'At-a-Glance' Series presents information on the numerous sources and magnitude of exposure of man to radiation. These include the medical use of radiation, radioactive discharges to the environment, cosmic rays, gamma rays from the ground and buildings, radon gas and food and drink. A Pie chart represents the percentage contribution of each of those sources. Finally, the terms becquerel, microsievert and millisievert are explained. (U.K.)

  19. Progress in high-dose radiation dosimetry

    International Nuclear Information System (INIS)

    Ettinger, K.V.; Nam, J.W.; McLaughlin, W.L.; Chadwick, K.H.

    1981-01-01

    The last decade has witnessed a deluge of new high-dose dosimetry techniques and expanded applications of methods developed earlier. Many of the principal systems are calibrated by means of calorimetry, although production of heat is not always the final radiation effect of interest. Reference systems also include a number of chemical dose meters: ferrous sulphate, ferrous-cupric sulphate, and ceric sulphate acidic aqueous solutions. Requirements for stable and reliable transfer dose meters have led to further developments of several important high-dose systems: amino acids and saccharides analysed by ESR or lyoluminescence, thermoluminescent materials, radiochromic dyes and plastics, ceric-cerous solutions analysed by potentiometry, and ethanol-chlorobenzene solutions analysed by high-frequency oscillometry. A number of other prospective dose meters are also treated in this review. In addition, an IAEA programme of high-dose standardization and intercomparison for industrial radiation processing is described. (author)

  20. 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)

  1. Radiation dose reduction in pediatric CT

    International Nuclear Information System (INIS)

    Robinson, A.E.; Hill, E.P.; Harpen, M.D.

    1986-01-01

    The relationship between image noise and radiation dose was investigated in computed tomography (CT) images of a pediatric abdomen phantom. A protocol which provided a minimum absorbed dose consistent with acceptable image noise criteria was determined for a fourth generation CT scanner. It was found that pediatric abdominal CT scans could maintain diagnostic quality with at least a 50% reduction in dose from the manufacturers' suggested protocol. (orig.)

  2. Dose mapping for documentation of radiation sterilization

    DEFF Research Database (Denmark)

    Miller, A.

    1999-01-01

    The radiation sterilization standards EN 552 and ISO 11137 require that dose mapping in real or simulated product be carried in connection with the process qualification. This paper reviews the recommendations given in the standards and discusses the difficulties and limitations of practical dose...... mapping. The paper further gives recommendations for effective dose mapping including traceable dosimetry, documented procedures for placement of dosimeters, and evaluation of measurement uncertainties. (C) 1999 Elsevier Science Ltd. All rights reserved....

  3. Cosmic radiation dose in the aircraft

    International Nuclear Information System (INIS)

    Vukovic, B.; Radolic, V.; Varga, M.; Planinic, J.; Vekic, B.

    2006-01-01

    When primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard A 320 and ATR 42 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; the neutron dose was measured with the neutron dosimeter consisted of LR-115 track detector and boron foil BN-1 or 10B converter. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed at the flights Zagreb - Paris - Buenos Aires and reversely, when one measured cosmic radiation dose; for 26.7 h of flight, the MINI 6100 dosimeter gave an average dose rate of 2.3 μSv/h and the TLD dosimeter registered the total dose of 75 μSv or the average dose rate of 2.7 μSv/h; the neutron dosimeter gave the dose rate of 2.4 μSv/h. In the same month, February 2005, a traveling to the Japan (24 hours-flight: Zagreb - Frankfurt - Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 μSv/h; the neutron dosimeter gave the dose rate of 2.5 μSv/h. Comparing dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level, we could conclude the neutron component curried about 50% of the total dose, that was near other known data. (author)

  4. Analysis of T101 outage radiation dose

    International Nuclear Information System (INIS)

    Li, Zhonghua

    2008-01-01

    Full text: Collective radiation dose during outage is about 80% of annual collective radiation dose at nuclear power plants (NPPs). T 101 Outage is the first four-year outage of Unit 1 at Tianwan Nuclear Power Station (TNPS) and thorough overhaul was undergone for the 105-day's duration. Therefore, T 101 Outage has significant reference meaning to reducing collective radiation dose at TNPS. This paper collects the radiation dose statistics during T 101 Outage and analyses the radiation dose distribution according to tasks, work kinds and varying trend of the collective radiation dose etc., comparing with other similar PWRs in the world. Based on the analysis this paper attempts to find out the major factors in collective radiation dose during T 101 Outage. The major positive factor is low radiation level at workplace, which profits from low content of Co in reactor construction materials, optimised high-temperature p H value of the primary circuit coolant within the tight range and reactor operation without trips within the first fuel cycle. One of the most negative factors is long outage duration and many person-hours spent in the radiological controlled zone, caused by too many tasks and inefficient work. So besides keeping good performance of reducing radioactive sources, it should be focused on how to improve implementation of work management including work selection, planning and scheduling, work preparation, work implementation, work assessment and feedback, which can lead to reduced numbers of workers needed to perform a task, of person-hours spent in the radiological controlled zone. Moreover, this leads to reduce occupational exposures in an ALARA fashion. (author)

  5. Work on optimum medical radiation doses

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2010-01-01

    Every day the medical world makes use of X-rays and radioisotopes. Radiology allows organs to be visualised, nuclear medicine diagnoses and treats cancer by injecting radioisotopes, and radiotherapy uses ionising radiation for cancer therapy. The medical world is increasingly mindful of the risks of ionising radiation that patients are exposed to during these examinations and treatments. In 2009 SCK-CEN completed two research projects that should help optimise the radiation doses of patients.

  6. Radiation Doses Received by the Irish Population

    International Nuclear Information System (INIS)

    Colgan, P.A.; Organo, C.; Hone, C.; Fenton, D.

    2008-05-01

    Some chemical elements present in the environment since the Earth was formed are naturally radioactive and exposure to these sources of radiation cannot be avoided. There have also been additions to this natural inventory from artificial sources of radiation that did not exist before the 1940s. Other sources of radiation exposure include cosmic radiation from outer space and the use of radiation in medical diagnosis and treatment. There can be large variability in the dose received by invividual members of the population from any given source. Some sources of radiation expose every member of the population while, in other cases, only selected individuals may be exposed. For example, natural radioactivity is found in all soils and therefore everybody receives some radiation dose from this activity. On the other hand, in the case of medical exposures, only those who undergo a medical procedure using radiation will receive a radiation dose. The Radiological Protection Institute of Ireland (RPII) has undertaken a comprehensive review of the relevant data on radiation exposure in Ireland. Where no national data have been identified, the RPII has either undertaken its own research or has referred to the international literature to provide a best estimate of what the exposure in Ireland might be. This has allowed the relative contribution of each source to be quantified. This new evaluation is the most up-to-date assessment of radiation exposure and updates the assessment previously reported in 2004. The dose quoted for each source is the annual 'per caput' dose calculated on the basis of the most recently available data. This is an average value calculated by adding the doses received by each individual exposed to a given radiation source and dividing the total by the current population of 4.24 million. All figures have been rounded, consistent with the accuracy of the data. In line with accepted international practice, where exposure takes place both indoors and

  7. Dose planning and dose delivery in radiation therapy

    International Nuclear Information System (INIS)

    Knoeoes, T.

    1991-01-01

    A method has been developed for calibration of CT-numbers to volumetric electron density distributions using tissue substitutes of known elemental composition and experimentally determined electron density. This information have been used in a dose calculation method based on photon and electron interaction processes. The method utilizes a convolution integral between the photon fluence matrix and dose distribution kernels. Inhomogeneous media are accounted for using the theorems of Fano and O'Connor for scaling dose distribution kernels in proportion to electron density. For clinical application of a calculated dose plan, a method for prediction of accelerator output have been developed. The methods gives the number of monitor units that has to be given to obtain a certain absorbed dose to a point inside an irregular, inhomogeneous object. The method for verification of dose distributions outlined in this study makes it possible to exclude the treatment related variance contributions, making an objective evaluation of dose calculations with experiments feasible. The methods for electron density determination, dose calculation and prediction of accelerator output discussed in this study will all contribute to an increased accuracy in the mean absorbed dose to the target volume. However, a substantial gain in the accuracy for the spatial absorbed dose distribution will also follow, especially using CT for mapping of electron density together with the dose calculation algorithm. (au)

  8. Radiation Dose from Reentrant Electrons

    Science.gov (United States)

    Badhwar, G.D.; Cleghorn, T. E.; Watts, J.

    2003-01-01

    In estimating the crew exposures during an EVA, the contribution of reentrant electrons has always been neglected. Although the flux of these electrons is small compared to the flux of trapped electrons, their energy spectrum extends to several GeV compared to about 7 MeV for trapped electrons. This is also true of splash electrons. Using the measured reentrant electron energy spectra, it is shown that the dose contribution of these electrons to the blood forming organs (BFO) is more than 10 times greater than that from the trapped electrons. The calculations also show that the dose-depth response is a very slowly changing function of depth, and thus adding reasonable amounts of additional shielding would not significantly lower the dose to BFO.

  9. Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice

    International Nuclear Information System (INIS)

    Ware, J.H.; Rusek, A.; Sanzari, J.; Avery, S.; Sayers, C.; Krigsfeld, G.; Nuth, M.; Wan, X.S.; Kennedy, A.R.

    2010-01-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

  10. Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice.

    Science.gov (United States)

    Ware, J H; Sanzari, J; Avery, S; Sayers, C; Krigsfeld, G; Nuth, M; Wan, X S; Rusek, A; Kennedy, A R

    2010-09-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

  11. Assessment of radiation dose awareness among pediatricians

    International Nuclear Information System (INIS)

    Thomas, Karen E.; Parnell-Parmley, June E.; Charkot, Ellen; BenDavid, Guila; Krajewski, Connie; Haidar, Salwa; Moineddin, Rahim

    2006-01-01

    There is increasing awareness among pediatric radiologists of the potential risks associated with ionizing radiation in medical imaging. However, it is not known whether there has been a corresponding increase in awareness among pediatricians. To establish the level of awareness among pediatricians of the recent publicity on radiation risks in children, knowledge of the relative doses of radiological investigations, current practice regarding parent/patient discussions, and the sources of educational input. Multiple-choice survey. Of 220 respondents, 105 (48%) were aware of the 2001 American Journal of Roentgenology articles on pediatric CT and radiation, though only 6% were correct in their estimate of the quoted lifetime excess cancer risk associated with radiation doses equivalent to pediatric CT. A sustained or transient increase in parent questioning regarding radiation doses had been noticed by 31%. When estimating the effective doses of various pediatric radiological investigations in chest radiograph (CXR) equivalents, 87% of all responses (and 94% of CT estimates) were underestimates. Only 15% of respondents were familiar with the ALARA principle. Only 14% of pediatricians recalled any relevant formal teaching during their specialty training. The survey response rate was 40%. Awareness of radiation protection issues among pediatricians is generally low, with widespread underestimation of relative doses and risks. (orig.)

  12. Beyond mean pharyngeal constrictor dose for beam path toxicity in non-target swallowing muscles: dose-volume correlates of chronic radiation-associated dysphagia (RAD) after oropharyngeal intensity modulated radiotherapy

    Science.gov (United States)

    2016-01-01

    Purpose/Objective(s) We sought to identify swallowing muscle dose-response thresholds associated with chronic radiation-associated dysphagia (RAD) after IMRT for oropharyngeal cancer. Materials/Methods T1-4 N0-3 M0 oropharyngeal cancer patients who received definitive IMRT and systemic therapy were examined. Chronic RAD was coded as any of the following ≥ 12 months post-IMRT: videofluoroscopy/endoscopy detected aspiration or stricture, gastrostomy tube and/or aspiration pneumonia. DICOM-RT plan data were autosegmented using a custom region-of-interest (ROI) library and included inferior, middle and superior constrictors (IPC, MPC, and SPC), medial and lateral pterygoids (MPM, LPM), anterior and posterior digastrics (ADM, PDM), intrinsic tongue muscles (ITM), mylo/geniohyoid complex (MHM), genioglossus (GGM), ), masseter (MM), Buccinator (BM), palatoglossus (PGM), and cricopharyngeus (CPM), with ROI dose-volume histograms (DVHs) calculated. Recursive partitioning analysis (RPA) was used to identify dose-volume effects associated with chronic-RAD, for use in a multivariate (MV) model. Results Of 300 patients, 34 (11%) had chronic-RAD. RPA showed DVH-derived MHM V69 (i.e. the volume receiving ≥69Gy), GGM V35, ADM V60, MPC V49, and SPC V70 were associated with chronic-RAD. A model including age in addition to MHM V69 as continuous variables was optimal among tested MV models (AUC 0.835). Conclusion In addition to SPCs, dose to MHM should be monitored and constrained, especially in older patients (>62-years), when feasible. PMID:26897515

  13. Beyond mean pharyngeal constrictor dose for beam path toxicity in non-target swallowing muscles: Dose-volume correlates of chronic radiation-associated dysphagia (RAD) after oropharyngeal intensity modulated radiotherapy.

    Science.gov (United States)

    2016-02-01

    We sought to identify swallowing muscle dose-response thresholds associated with chronic radiation-associated dysphagia (RAD) after IMRT for oropharyngeal cancer. T1-4 N0-3 M0 oropharyngeal cancer patients who received definitive IMRT and systemic therapy were examined. Chronic RAD was coded as any of the following ⩾12months post-IMRT: videofluoroscopy/endoscopy detected aspiration or stricture, gastrostomy tube and/or aspiration pneumonia. DICOM-RT plan data were autosegmented using a custom region-of-interest (ROI) library and included inferior, middle and superior constrictors (IPC, MPC, and SPC), medial and lateral pterygoids (MPM, LPM), anterior and posterior digastrics (ADM, PDM), intrinsic tongue muscles (ITM), mylo/geniohyoid complex (MHM), genioglossus (GGM), masseter (MM), buccinator (BM), palatoglossus (PGM), and cricopharyngeus (CPM), with ROI dose-volume histograms (DVHs) calculated. Recursive partitioning analysis (RPA) was used to identify dose-volume effects associated with chronic-RAD, for use in a multivariate (MV) model. Of 300 patients, 34 (11%) had chronic-RAD. RPA showed DVH-derived MHM V69 (i.e. the volume receiving⩾69Gy), GGM V35, ADM V60, MPC V49, and SPC V70 were associated with chronic-RAD. A model including age in addition to MHM V69 as continuous variables was optimal among tested MV models (AUC 0.835). In addition to SPCs, dose to MHM should be monitored and constrained, especially in older patients (>62-years), when feasible. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. The Dose Response Relationship for Radiation Carcinogenesis

    Science.gov (United States)

    Hall, Eric

    2008-03-01

    Recent surveys show that the collective population radiation dose from medical procedures in the U.S. has increased by 750% in the past two decades. It would be impossible to imagine the practice of medicine today without diagnostic and therapeutic radiology, but nevertheless the widespread and rapidly increasing use of a modality which is a known human carcinogen is a cause for concern. To assess the magnitude of the problem it is necessary to establish the shape of the dose response relationship for radiation carcinogenesis. Information on radiation carcinogenesis comes from the A-bomb survivors, from occupationally exposed individuals and from radiotherapy patients. The A-bomb survivor data indicates a linear relationship between dose and the risk of solid cancers up to a dose of about 2.5 Sv. The lowest dose at which there is a significant excess cancer risk is debatable, but it would appear to be between 40 and 100 mSv. Data from the occupation exposure of nuclear workers shows an excess cancer risk at an average dose of 19.4 mSv. At the other end of the dose scale, data on second cancers in radiotherapy patients indicates that cancer risk does not continue to rise as a linear function of dose, but tends towards a plateau of 40 to 60 Gy, delivered in a fractionated regime. These data can be used to estimate the impact of diagnostic radiology at the low dose end of the dose response relationship, and the impact of new radiotherapy modalities at the high end of the dose response relationship. In the case of diagnostic radiology about 90% of the collective population dose comes from procedures (principally CT scans) which involve doses at which there is credible evidence of an excess cancer incidence. While the risk to the individual is small and justified in a symptomatic patient, the same is not true of some screening procedures is asymptomatic individuals, and in any case the huge number of procedures must add up to a potential public health problem. In the

  15. Potential gonadal dose from leakage radiation?

    International Nuclear Information System (INIS)

    Nicholson, R.A.

    1995-01-01

    The author draws attention to the potential dangers of leakage radiation from mobile image intensifier units, and points out that during interventional urological procedures, radiation from below the urologist's knees may irradiate male gonads without being intercepted by protective aprons. Results are presented for a Shimatzu WHA mobile II, phantom doses being measured with an ionization chamber. Dose rates measured in the male gonad position were compared with rates at waist level behind a 0.35 mm lead equivalent shielding and dose rates at collar level outside the lead apron. Results are also presented of a study on the effect on gonad dose of a) adding 0.7 mm lead shielding to the tube housing and b) adding 0.7 mm lead and removing the spacer cone to reduce scatter. Results show that it is possible for gonad doses to be comparable with those assumed for the eyes, rather than the body. (Author)

  16. 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

  17. Radiation dose from cigarette tobacco

    International Nuclear Information System (INIS)

    Papastefanou, Constantin

    2008-01-01

    The radioactivity in tobacco leaves collected from 15 different regions of Greece before cigarette production was studied in order to estimate the effective dose from cigarette tobacco due to the naturally occurring primordial radionuclides, such as 226 Ra and 210 Pb of the uranium series and 228 Ra of the thorium series and or man-made produced radionuclides, such as 137 Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the annual effective dose due to inhalation for adults (smokers) for 226 Ra varied from 42.5 to 178.6 μSv y -1 (average 79.7 μSv y -1 ), while for 228 Ra from 19.3 to 116.0 μSv y -1 (average 67.1 μSv y -1 ) and for 210 Pb from 47.0 to 134.9 μSv y -1 (average 104.7 μSv y -1 ), that is the same order of magnitude for each radionuclide. The sum of the effective dose of the three natural radionuclides varied from 151.9 to 401.3 μSv y -1 (average 251.5 μSv y -1 ). The annual effective dose from 137 Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 μSv y -1 (average 199.3 μSv y -1 ). (author)

  18. Low radiation doses and antinuclear lobby

    International Nuclear Information System (INIS)

    Drobnik, J.

    1987-01-01

    The probability of mutations or diseases resulting from other than radiation causes is negatively dependent on radiation. Thus, for instance, the incidence of cancer, is demonstrably lower in areas with a higher radiation background. The hypothesis is expressed that there exist repair mechanisms for DNA damage which will repair the damage, and will give priority to those genes which are currently active. Survival and stochastic processes are not dependent on the overall repair of DNA but on the repair of critical function genes. New discoveries shed a different light on views of the linear dependence of radiation damage on the low level doses. (M.D.)

  19. A trial of radiation dose prescription based on dose-cell survival formula

    International Nuclear Information System (INIS)

    Allen, E.P.

    1984-01-01

    Radiation treatment has been prescribed for 379 basal cell carcinomata on the basis of a selected equivalent single dose derived from the standard multi-target dose-cell survival formula using values of m = 2 and Do = 130 rads for orthovoltage x-rays. The results suggest that the approach provides a flexible and acceptable alternative to prescription by total dose or by Nominal Standard Dose. It is submitted that Total Dose is an inadequate expression of radiobiological effects: that the NSD and related systems are valuable measures of the ability of normal tissues to recover from radiation damage: and that a parallel measure of the degree of tumour depopulation has become necessary to allow further progress in alternative fractionation schedules

  20. Analytical dose modeling for preclinical proton irradiation of millimetric targets.

    Science.gov (United States)

    Vanstalle, Marie; Constanzo, Julie; Karakaya, Yusuf; Finck, Christian; Rousseau, Marc; Brasse, David

    2018-01-01

    Due to the considerable development of proton radiotherapy, several proton platforms have emerged to irradiate small animals in order to study the biological effectiveness of proton radiation. A dedicated analytical treatment planning tool was developed in this study to accurately calculate the delivered dose given the specific constraints imposed by the small dimensions of the irradiated areas. The treatment planning system (TPS) developed in this study is based on an analytical formulation of the Bragg peak and uses experimental range values of protons. The method was validated after comparison with experimental data from the literature and then compared to Monte Carlo simulations conducted using Geant4. Three examples of treatment planning, performed with phantoms made of water targets and bone-slab insert, were generated with the analytical formulation and Geant4. Each treatment planning was evaluated using dose-volume histograms and gamma index maps. We demonstrate the value of the analytical function for mouse irradiation, which requires a targeting accuracy of 0.1 mm. Using the appropriate database, the analytical modeling limits the errors caused by misestimating the stopping power. For example, 99% of a 1-mm tumor irradiated with a 24-MeV beam receives the prescribed dose. The analytical dose deviations from the prescribed dose remain within the dose tolerances stated by report 62 of the International Commission on Radiation Units and Measurements for all tested configurations. In addition, the gamma index maps show that the highly constrained targeting accuracy of 0.1 mm for mouse irradiation leads to a significant disagreement between Geant4 and the reference. This simulated treatment planning is nevertheless compatible with a targeting accuracy exceeding 0.2 mm, corresponding to rat and rabbit irradiations. Good dose accuracy for millimetric tumors is achieved with the analytical calculation used in this work. These volume sizes are typical in mouse

  1. Dose distribution following selective internal radiation therapy

    International Nuclear Information System (INIS)

    Fox, R.A.; Klemp, P.F.; Egan, G.; Mina, L.L.; Burton, M.A.; Gray, B.N.

    1991-01-01

    Selective Internal Radiation Therapy is the intrahepatic arterial injection of microspheres labelled with 90Y. The microspheres lodge in the precapillary circulation of tumor resulting in internal radiation therapy. The activity of the 90Y injected is managed by successive administrations of labelled microspheres and after each injection probing the liver with a calibrated beta probe to assess the dose to the superficial layers of normal tissue. Predicted doses of 75 Gy have been delivered without subsequent evidence of radiation damage to normal cells. This contrasts with the complications resulting from doses in excess of 30 Gy delivered from external beam radiotherapy. Detailed analysis of microsphere distribution in a cubic centimeter of normal liver and the calculation of dose to a 3-dimensional fine grid has shown that the radiation distribution created by the finite size and distribution of the microspheres results in an highly heterogeneous dose pattern. It has been shown that a third of normal liver will receive less than 33.7% of the dose predicted by assuming an homogeneous distribution of 90Y

  2. Radiation absorbed dose from medically administered radiopharmaceuticals

    International Nuclear Information System (INIS)

    Roedler, H.D.; Kaul, A.

    1975-01-01

    The use of radiopharmaceuticals for medical examinations is increasing. Surveys carried out in West Berlin show a 20% average yearly increase in such examinations. This implies an increased genetic and somatic radiation exposure of the population in general. Determination of radiation exposure of the population as well as of individual patients examined requires a knowledge of the radiation dose absorbed by each organ affected by each examination. An extensive survey of the literature revealed that different authors reported widely different dose values for the same defined examination methods and radiopharmaceuticals. The reason for this can be found in the uncertainty of the available biokinetic data for dose calculations and in the application of various mathematical models to describe the kinetics and calculation of organ doses. Therefore, the authors recalculated some of the dose values published for radiopharmaceuticals used in patients by applying biokinetic data obtained from exponential models of usable metabolism data reported in the literature. The calculation of organ dose values was done according to the concept of absorbed fractions in its extended form. For all radiopharmaceuticals used in nuclear medicine the energy dose values for the most important organs (ovaries, testicles, liver, lungs, spleen, kidneys, skeleton, total body or residual body) were recalculated and tabulated for the gonads, skeleton and critical or examined organs respectively. These dose values are compared with those reported in the literature and the reasons for the observed deviations are discussed. On the basis of recalculated dose values for the gonads and bone-marrow as well as on the basis of results of statistical surveys in West Berlin, the genetically significant dose and the somatically (leukemia) significant dose were calculated for 1970 and estimated for 1975. For 1970 the GSD was 0.2 mrad and the LSD was 0.7 mrad. For 1975 the GSD is estimated at < 0.5 mrad and the

  3. Internal radiation dose of Indians

    International Nuclear Information System (INIS)

    Ranganathan, S.; Nagaratnam, A.; Sharma, U.C.

    2001-01-01

    The measurement of γ-rays from 40 K by whole-body counting provides a sensitive technique to estimate the body 40 K radioactivity. In India, right from the whole body counter (WBC) of Trombay in the early 1960s to the INMAS WBC of 1970s, some limited information has been available about the internal 40 K of Indians. However, information on 40 K dose with age and sex of Indians is scanty. Therefore, a systematic study was taken up to generate this information

  4. Radiation doses from computed tomography in Australia

    International Nuclear Information System (INIS)

    Thomson, J.E.M.; Tingey, D.R.C.

    1997-11-01

    Recent surveys in various countries have shown that computed tomography (CT) is a significant and growing contributor to the radiation dose from diagnostic radiology. Australia, with 332 CT scanners (18 per million people), is well endowed with CT equipment compared to European countries (6 to 13 per million people). Only Japan, with 8500 units (78 per million people), has a significantly higher proportion of CT scanners. In view of this, a survey of CT facilities, frequency of examinations, techniques and patient doses has been performed in Australia. It is estimated that there are 1 million CT examinations in Australia each year, resulting in a collective effective dose of 7000 Sv and a per caput dose of 0.39 mSv. This per caput dose is much larger than found in earlier studies in the UK and New Zealand but is less than 0.48 mSv in Japan. Using the ICRP risk factors, radiation doses from CT could be inducing about 280 fatal cancers per year in Australia. CT is therefore a significant, if not the major, single contributor to radiation doses and possible risk from diagnostic radiology. (authors)

  5. Radiation doses from phosphate fertilizers

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    The activity concentrations determined of 226 Ra, 232 Th and 40 K in nCi/kg P 2 O 5 for the five most important kinds of fertilizer as well as their percent share in the economy year 1973/74 in the FRG are compiled in a table. From these values, the consumption of 0.917 million tons P 2 O 5 and from an average annual fertilizer coverage of 68.3 kg/ha, one can calculate a distribution of 32 Ci 226 Ra, 1 Ci 232 Th and 543 Ci 40 K over the total agriculturally used area, in other words, a deposit of 2.4 μCi 226 Ra, 0.07 μCi 232 Th and 40.5 μCi 40 K per ha. Taking a pessimistic view, an external radiation exposure of 0.11 mrad/a was calculated for gonads and bone marrow. If the total accumulation of 226 Ra (38% of the radiation exposure) from phosphate fertilizers from the ground during the last 80 years is assumed, then there is an exposure of 1.7 mrad/a for individual members of the population and 2.0 mrad/a for those occupied in agriculture. (HP/LH) [de

  6. Metrology of radiation doses in diagnostic radiology

    International Nuclear Information System (INIS)

    Leclet, H.

    2016-01-01

    This article recalls how to calculate effective and equivalent doses in radiology from the measured value of the absorbed dose. The 97/43 EURATOM directive defines irradiation standards for diagnostic radiology (NRD) as the value of the radiation dose received by the patient's skin when the diagnostic exam is performed. NRD values are standard values that can be exceeded only with right medical or technical reasons, they are neither limit values nor optimized values. The purpose of NRD values is to avoid the over-irradiation of patients and to homogenize radiologists' practices. French laws impose how and when radiologists have to calculate the radiation dose received by the patient's skin. The calculated values have to be compared with NRD values and any difference has to be justified. A table gives NRD values for all diagnostic exams. (A.C.)

  7. Epigenomic Adaptation to Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-30

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

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

    International Nuclear Information System (INIS)

    Ma, C-M; Li Jinsheng

    2011-01-01

    The Monte Carlo method enables accurate dose calculation for radiation therapy treatment planning and has been implemented in some commercial treatment planning systems. Unlike conventional dose calculation algorithms that provide patient dose information in terms of dose to water with variable electron density, the Monte Carlo method calculates the energy deposition in different media and expresses dose to a medium. This paper discusses the differences in dose calculated using water with different electron densities and that calculated for different biological media and the clinical issues on dose specification including dose prescription and plan evaluation using dose to water and dose to medium. We will demonstrate that conventional photon dose calculation algorithms compute doses similar to those simulated by Monte Carlo using water with different electron densities, which are close (<4% differences) to doses to media but significantly different (up to 11%) from doses to water converted from doses to media following American Association of Physicists in Medicine (AAPM) Task Group 105 recommendations. Our results suggest that for consistency with previous radiation therapy experience Monte Carlo photon algorithms report dose to medium for radiotherapy dose prescription, treatment plan evaluation and treatment outcome analysis.

  9. Effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Anon.

    2008-01-01

    Ionizing radiation of cosmic or terrestrial origin is part of the environment in which all living things have evolved since the creation of the universe. The artificial radioactivity generated by medical diagnostic and treatment techniques, some industrial activities, radioactive fallout, etc. has now been added to this natural radioactivity. This article reviews the biological effects of the low doses of ionizing radiation to which the population is thus exposed. Their carcinogenic risk cannot simply be extrapolated from what we know about high-dose exposure. (author)

  10. Tumor induction by small doses ionising radiation

    International Nuclear Information System (INIS)

    Putten, L.M. van

    1981-01-01

    Tumour induction by low radiation doses is in general a non-linear process. However, two exceptions are well known: myeloid leukemia in Rf mice and mamma tumours in Sprague-Dawley rats. The hypothesis that radiation is highly oncogenic in combination with cell growth stimuli, as reaction to massive cell death after damage of nuclear DNA, is applied to man and the consequences are discussed. (Auth.)

  11. Visual indicator of absorbed radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Generalova, V V; Krasovitskii, B M; Vainshtok, B A; Gurskii, M N

    1968-10-15

    A visual indicator of the absorbed doses of ionizing radiation is proposed. The indicator has a polymer base with the addition of a dye. A distinctive feature of the indicator consists of the use of polystyrene as its polymer base with the addition of halogen-containing hydrocarbon and the light-proof dye. Such combination of the radiation-resistant polymer of polystyrene and the light-proof dyestuff makes the proposed indicator highly stable.

  12. TLD array for precise dose measurements in stereotactic radiation techniques

    International Nuclear Information System (INIS)

    Ertl, A.; Kitz, K.; Griffitt, W.; Hartl, R.F.E.; Zehetmayer, M.

    1996-01-01

    We developed a new TLD array for precise dose measurement and verification of the spatial dose distribution in small radiation targets. It consists of a hemicylindrical, tissue-equivalent rod made of polystyrene with 17 parallel moulds for an exact positioning of each TLD. The spatial resolution of the TLD array was evaluated using the Leskell spherical phantom. Dose planning was performed with KULA 4.4 under stereotactic conditions on axial CT images. In the Leksell gamma unit the TLD array was irradiated with a maximal dose of 10 Gy with an unplugged 14 mm collimator. The doses delivered to the TLDs were rechecked by diode detector and film dosimetry and compared to the computer-generated dose profile. We found excellent agreement of our measured values, even at the critical penumbra decline. For the 14 mm and 18 mm collimator and for the 11 mm collimator combination we compared the measured and calculated data at full width at half maximum. This TLD array may be useful for phantom or tissue model studies on the spatial dose distribution in confined radiation targets as used in stereotactic radiotherapy. (author)

  13. Biological evidence of low ionizing radiation doses

    International Nuclear Information System (INIS)

    Mirsch, Johanna

    2017-01-01

    Throughout life, every person is constantly exposed to different types of ionising radiation, without even noticing the exposure. The mean radiation exposure for people living in Germany amounts to approximately 4 mSv per year and encompasses the exposure from natural and man-made sources. The risks associated with exposure to low doses of radiation are still the subject of intense and highly controversial discussions, emphasizing the social relevance of studies investigating the effects of low radiation doses. In this thesis, DNA double-strand breaks (DSBs) were analyzed within three projects covering different aspects. DSBs are among the most hazardous DNA lesions induced by ionizing radiation, because this type of damage can easily lead to the loss of genetic information. Consequently, the DSB presents a high risk for the genetic integrity of the cell. In the first project, extensive results uncovered the track structure of charged particles in a biological model tissue. This provided the first biological data that could be used for comparison with data that were measured or predicted using theoretical physical dosimetry methods and mathematical simulations. Charged particles contribute significantly to the natural radiation exposure and are used increasingly in cancer radiotherapy because they are more efficient in tumor cell killing than X- or γ-rays. The difference in the biological effects of high energy charged particles compared with X- or γ-rays is largely determined by the spatial distribution of their energy deposition and the track structure inducing a three-dimensional damage pattern in living cells. This damage pattern consists of cells directly hit by the particle receiving a high dose and neighboring cells not directly hit by primary particles but exposed to far-reaching secondary electrons (δ-electrons). These cells receive a much lower dose deposition in the order of a few mGy. The radial dose distribution of single particle tracks was

  14. Effects of small doses of ionising radiation

    International Nuclear Information System (INIS)

    Doll, R.

    1998-01-01

    Uncertainty remains about the quantitative effects of doses of ionising radiation less than 0.2 Sv. Estimates of hereditary effects, based on the atomic bomb survivors, suggest that the mutation doubling dose is about 2 Sv for acute low LET radiation, but the confidence limits are wide. The idea that paternal gonadal irradiation might explain the Seascale cluster of childhood leukaemia has been disproved. Fetal irradiation may lead to a reduction in IQ and an increase in seizures in childhood proportional to dose. Estimates that doses to a whole population cause a risk of cancer proportional to dose, with 0.1 Sv given acutely causing a risk of 1%, will need to be modified as more information is obtained, but the idea that there is a threshold for risk above this level is not supported by observations on the irradiated fetus or the effect of fallout. The idea, based on ecological observations, that small doses protect against the development of cancer is refuted by the effect of radon in houses. New observations on the atomic bomb survivors have raised afresh the possibility that small doses may also have other somatic effects. (author)

  15. Radiologist and angiographic procedures. Absorbed radiation dose

    International Nuclear Information System (INIS)

    Tryhus, M.; Mettler, F.A. Jr.; Kelsey, C.

    1987-01-01

    The radiation dose absorbed by the angiographer during angiographic procedures is of vital importance to the radiologist. Nevertheless, most articles on the subject are incomplete, and few measure gonadal dose. In this study, three TLDs were used for each of the following sites: radiologist's eyes, thyroid, gonads with and without shielding apron, and hands. The average dose during carotid angiograms was 2.6, 4.1, 0.4, 4.7, and 7.1 mrads to the eyes, thyroid, gonads with and without .5 mm of lead shielding, and hands, respectively. Average dose during abdominal and peripheral vascular angiographic procedures was 5.2, 7.5, 1.2, 8.5, and 39.9 mrads to the eyes, thyroid, gonads with and without shielding, and hands, respectively. A literature review demonstrates a significant reduction in radiation dose to the angiographer after the advent of automated injectors. Our measured doses for carotid angiography are compatible with contemporary reported values. There was poor correlation with fluoroscopy time and measured dose to the angiographer

  16. When treating prostate cancer with three-dimensional conformal radiation therapy the impact of bladder filling status on the volume and integral dose distribution of the target and critical organs should be kept in mind

    International Nuclear Information System (INIS)

    Liu Yueping; Liu Xinfan; Li Yexiong; Guang Ying

    2007-01-01

    Objective: In prostate cancer treated with three-dimensional conformal radiation therapy (3DCRT), we tried to prospectively assess the impact of the filling status of bladder on the volume and the integral dose distribution to the target and surrounding critical organs. Methods: Ten patients with stage T1-T2N0M0 prostate cancer were studied. All patients received 3DCRT to the prostate and inferior seminal vesicle. One hour before CT simulation, the bladder was first voided, and then 400 ml of oral contrast solution was given at every half hour before the CT scan. Urethral catheterization was used for voiding or distending the bladder. When distending the bladder, 250-300 ml of contrast was injected into the bladder with the patient fixed at the supine position. Two sets of transverse images were taken for the whole pelvis in empty and full bladder. After the target and critical organs (bladder, rectum, pelvic small bowel, and femoral heads) were contoured, a treatment plan of three-dimensional conformal radiotherapy was made using the CMS Focus-Xio treatment planning system. The volume and mean doses of CTV, PTV, rectum, bladder, femoral heads, and small bowel with the bladder empty and full were evaluated. The percentage of volume which received 50 Gy in the rectum and bladder, 30 Gy in the femoral heads, and the maximal dose to the pelvic small bowel were also assessed . The variability of volume and dose distribution in these targets or organs was compared between the empty and full bladder status. Results: Comparing to the bladder empty status, full bladder led to a mean increase of 499% in the bladder volume, (67±9) ml and (336±48) ml (P=0.000), respectively. No volume change was found in the CTV, PTV, rectum, femoral heads and pel- vic small bowel(P=0.153,0.501,0.929,0.771,0.081). The mean dose to the bladder in full status was only 35% of that in empty status, (1501±201 ) cGy and (4267±216) cGy(P =0.000), respectively. The mean dose to the pelvic small

  17. Methionine Uptake and Required Radiation Dose to Control Glioblastoma

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-01

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

  18. Radiation dose effects, hardening of electronic components

    International Nuclear Information System (INIS)

    Dupont-Nivet, E.

    1991-01-01

    This course reviews the mechanism of interaction between ionizing radiation and a silicon oxide type dielectric, in particular the effect of electron-hole pairs creation in the material. Then effects of cumulated dose on electronic components and especially in MOS technology are examined. Finally methods hardening of these components are exposed. 93 refs

  19. Bio-indicators for radiation dose assessment

    International Nuclear Information System (INIS)

    Trivedi, A.

    1990-12-01

    In nuclear facilities, such as Chalk River Laboratories, dose to the atomic radiation workers (ARWs) is assessed routinely by using physical dosimeters and bioassay procedures in accordance with regulatory recommendations. However, these procedures may be insufficient in some circumstances, e.g., in cases where the reading of the physical dosimeters is questioned, in cases of radiation accidents where the person(s) in question was not wearing a dosimeter, or in the event of a radiation emergency when an exposure above the dose limits is possible. The desirability of being able to assess radiation dose on the basis of radio-biological effects has prompted the Dosimetric Research Branch to investigate the suitability of biological devices and techniques that could be used for this purpose. Current biological dosimetry concepts suggest that there does not appear to be any bio-indicator that could reliably measure the very low doses that are routinely measured by the physical devices presently in use. Nonetheless, bio-indicators may be useful in providing valuable supplementary information in cases of unusual radiation exposures, such as when the estimated body doses are doubtful because of lack of proper physical measurements, or in cases where available results need to be confirmed for medical treatment plannings. This report evaluates the present state of biological dosimetry and, in particular, assesses the efficiency and limits of individual indicators. This has led to the recommendation of a few promising research areas that may result in the development of appropriate biological dosimeters for operational and emergency needs at Chalk River

  20. Radiation doses and risks from internal emitters

    International Nuclear Information System (INIS)

    Harrison, John; Day, Philip

    2008-01-01

    This review updates material prepared for the UK Government Committee Examining Radiation Risks from Internal Emitters (CERRIE) and also refers to the new recommendations of the International Commission on Radiological Protection (ICRP) and other recent developments. Two conclusions from CERRIE were that ICRP should clarify and elaborate its advice on the use of its dose quantities, equivalent and effective dose, and that more attention should be paid to uncertainties in dose and risk estimates and their implications. The new ICRP recommendations provide explanations of the calculation and intended purpose of the protection quantities, but further advice on their use would be helpful. The new recommendations refer to the importance of understanding uncertainties in estimates of dose and risk, although methods for doing this are not suggested. Dose coefficients (Sv per Bq intake) for the inhalation or ingestion of radionuclides are published as reference values without uncertainty. The primary purpose of equivalent and effective dose is to enable the summation of doses from different radionuclides and from external sources for comparison with dose limits, constraints and reference levels that relate to stochastic risks of whole-body radiation exposure. Doses are calculated using defined biokinetic and dosimetric models, including reference anatomical data for the organs and tissues of the human body. Radiation weighting factors are used to adjust for the different effectiveness of different radiation types, per unit absorbed dose (Gy), in causing stochastic effects at low doses and dose rates. Tissue weighting factors are used to take account of the contribution of individual organs and tissues to overall detriment from cancer and hereditary effects, providing a simple set of rounded values chosen on the basis of age- and sex-averaged values of relative detriment. While the definition of absorbed dose has the scientific rigour required of a basic physical quantity

  1. Scatter Dose in Patients in Radiation Therapy

    International Nuclear Information System (INIS)

    Schmidt, W. F. O.

    2003-01-01

    Patients undergoing radiation therapy are often treated with high energy radiation (bremsstrahlung) which causes scatter doses in the patients from various sources as photon scatter coming from collimator, gantry, patient, patient table or room (walls, floor, air) or particle doses resulting from gamma-particle reactions in the atomic nucleus if the photon energies are above 8 MeV. In the last years new treatment techniques like IMRT (esp the step-and-shoot- or the MIMIC-techniques) have increased interest in these topics again. In the lecture an overview about recent measurements on scatter doses resulting from gantry, table and room shall be given. Scatter doses resulting from the volume treated in the patient to other critical parts of the body like eyes, ovarii etc. have been measured in two diploma works in our institute and are compared with a program (PERIDOSE; van der Giessen, Netherlands) to estimate them. In some cases these scatter doses have led to changes of treatment modalities. Also an overview and estimation of doses resulting from photon-particle interactions is given according to a publication from Gudowska et al.(Gudowska I, Brahme A, Andreo P, Gudowski W, Kierkegaard J. Calculation of absorbed dose and biological effectiveness from photonuclear reactions in a bremsstrahlung beam of end point 50 MeV. Phys Med Biol 1999; 44(9):2099-2125.). Energy dose has been calculated with Monte Carlo-methods and is compared with analytical methods for 50 MV bremsstrahlung. From these data biologically effective doses from particles in different depths of the body can be estimated also for energies used in normal radiotherapy. (author)

  2. Radiation doses from radioactivity in incandescent mantles

    International Nuclear Information System (INIS)

    1985-01-01

    Thorium nitrate is used in the production of incandescent mantles for gas lanterns. In this report dose estimates are given for internal and external exposure that result from the use of the incandescent mantles for gas lanterns. The collective, effective dose equivalent for all users of gas mantles is estimated to be about 100 Sv per annum in the Netherlands. For the population involved (ca. 700,000 persons) this is roughly equivalent to 5% to 10% of the collective dose equivalent associated with exposure to radiation from natural sources. The major contribution to dose estimates comes from inhalation of radium during burning of the mantles. A pessimistic approach results in individual dose estimates for inhalation of up to 0.2 mSv. Consideration of dose consequences in case of a fire in a storage department learns that it is necessary for emergency personnel to wear respirators. It is concluded that the uncontrolled removal of used gas mantles to the environment (soil) does not result in a significant contribution to environmental radiation exposure. (Auth.)

  3. Radiation therapy tolerance doses for treatment planning

    International Nuclear Information System (INIS)

    Lyman, J.T.

    1987-01-01

    To adequately plan acceptable dose distributions for radiation therapy treatments it is necessary to ensure that normal structures do not receive unacceptable doses. Acceptable doses are generally those that are below a stated tolerance dose for development of some level of complication. To support the work sponsored by the National Cancer Institute, data for the tolerance of normal tissues or organs to low-LET radiation has been compiled from a number of sources. These tolerance dose data are ostensibly for uniform irradiation of all or part of an organ, and are for either 5% (TD 5 ) or 50% (TD 50 ) complication probability. The ''size'' of the irradiated organ is variously stated in terms of the absolute volume or the fraction of the organ volume irradiated, or the area or the length of the treatment field. The accuracy of these data is questionable. Much of the data represent doses that one or several experienced therapists have estimated could be safely given rather than quantitative analyses of clinical observations. Because these data have been obtained from multiple sources with possible different criteria for the definition of a complication, there are sometimes different values for what is apparently the same end point. 20 refs., 1 fig., 1 tab

  4. Radiation dose measurement in gastrointestinal studies

    International Nuclear Information System (INIS)

    Sulieman, A.; Elzaki, M.; Kappas, C.; Theodorou, K.

    2011-01-01

    Barium studies investigations (barium swallow, barium meal and barium enema) are the basic routine radiological examination, where barium sulphate suspension is introduced to enhance image contrast of gastrointestinal tracts. The aim of this study was to quantify the patients' radiation doses during barium studies and to estimate the organ equivalent dose and effective dose with those procedures. A total of 33 investigations of barium studies were measured by using thermoluminescence dosemeters. The result showed that the patient entrance surface doses were 12.6±10, 44.5±49 and 35.7±50 mGy for barium swallow, barium meal, follow through and enema, respectively. Effective doses were 0.2, 0.35 and 1.4 mSv per procedure for barium swallow, meal and enema respectively. Radiation doses were comparable with the previous studies. A written protocol for each procedure will reduce the inter-operator variations and will help to reduce unnecessary exposure. (authors)

  5. Non-targeted effects of ionising radiation - Implications for radiation protection

    International Nuclear Information System (INIS)

    Sisko Salomaa

    2006-01-01

    The universality of the target theory of radiation-induced effects is challenged by observations on non-targeted effects such as bystander effects, genomic instability and adaptive response. Essential features of non-targeted effects are that they do not require direct nuclear exposure by radiation and they are particularly significant at low doses. This new evidence suggests a need for a new paradigm in radiation biology. The new paradigm should cover both the classical (targeted) and the non-targeted effects. New aspects include the role of cellular communication and tissue-level responses. A better understanding of non-targeted effects may have important consequences for health risk assessment and, consequently, on radiation protection. Non-targeted effects may contribute to the estimation of cancer risk from occupational, medical and environmental exposures. In particular, they may have implications for the applicability of the Linear-No-Threshold (LNT) model in extrapolating radiation risk data into the low-dose region. This also means that the adequacy of the concept of dose to estimate risk is challenged by these findings. Moreover, these effects may provide new mechanistic explanations for the development of non-cancer diseases. Further research is required to determine if these effects, typically measured in cell cultures, are applicable in tissue level, whole animals, and ultimately in humans. (author)

  6. Non-targeted effects of ionising radiation - Implications for radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Sisko Salomaa [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland)

    2006-07-01

    The universality of the target theory of radiation-induced effects is challenged by observations on non-targeted effects such as bystander effects, genomic instability and adaptive response. Essential features of non-targeted effects are that they do not require direct nuclear exposure by radiation and they are particularly significant at low doses. This new evidence suggests a need for a new paradigm in radiation biology. The new paradigm should cover both the classical (targeted) and the non-targeted effects. New aspects include the role of cellular communication and tissue-level responses. A better understanding of non-targeted effects may have important consequences for health risk assessment and, consequently, on radiation protection. Non-targeted effects may contribute to the estimation of cancer risk from occupational, medical and environmental exposures. In particular, they may have implications for the applicability of the Linear-No-Threshold (LNT) model in extrapolating radiation risk data into the low-dose region. This also means that the adequacy of the concept of dose to estimate risk is challenged by these findings. Moreover, these effects may provide new mechanistic explanations for the development of non-cancer diseases. Further research is required to determine if these effects, typically measured in cell cultures, are applicable in tissue level, whole animals, and ultimately in humans. (author)

  7. Patient radiation doses from neuroradiology procedures

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Roman, M J; Abreu-Luis, J; Hernandez-Armas, J [Servicio de Fisica Medica, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain); Prada-Martinez, E [Servicio de Radiodiagnostico, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain)

    2001-03-01

    Following the presentation of radiation-induced deterministic effects by some patients undergoing neuroradiological procedures during successive sessions, such as temporary epilation, in the 'Hospital Universitario de Canarias', measurements were made of dose to patients. The maximum dose-area product measured by ionization chamber during these procedures was 39617 cGy.cm{sup 2} in a diagnostic of aneurysm and the maximum dose to the skin measured by thermoluminescent dosemeters (TLDs) was 462.53 mGy. This can justify certain deterministic effects but it is unlikely that the patients will suffer serious effects from this skin dose. Also, measurements were made of effective dose about two usual procedures, embolisation of tumour und embolisation of aneurysm. These procedures were reproduced with an anthropomorphic phantom Rando and doses were measured with TLDs. Effective doses obtained were 3.79 mSv and 4.11 mSv, respectively. The effective dose valued by the program EFFDOSE was less than values measured with TLDs. (author)

  8. Patient radiation doses from neuroradiology procedures

    International Nuclear Information System (INIS)

    Garcia-Roman, M.J.; Abreu-Luis, J.; Hernandez-Armas, J.; Prada-Martinez, E.

    2001-01-01

    Following the presentation of radiation-induced deterministic effects by some patients undergoing neuroradiological procedures during successive sessions, such as temporary epilation, in the 'Hospital Universitario de Canarias', measurements were made of dose to patients. The maximum dose-area product measured by ionization chamber during these procedures was 39617 cGy.cm 2 in a diagnostic of aneurysm and the maximum dose to the skin measured by thermoluminescent dosemeters (TLDs) was 462.53 mGy. This can justify certain deterministic effects but it is unlikely that the patients will suffer serious effects from this skin dose. Also, measurements were made of effective dose about two usual procedures, embolisation of tumour und embolisation of aneurysm. These procedures were reproduced with an anthropomorphic phantom Rando and doses were measured with TLDs. Effective doses obtained were 3.79 mSv and 4.11 mSv, respectively. The effective dose valued by the program EFFDOSE was less than values measured with TLDs. (author)

  9. 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

  10. Internal radiation dose in diagnostic nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Roedler, H D; Kaul, A; Hine, G J

    1978-01-01

    Absorbed dose values per unit administered activity for the most frequently used radipharmaceuticals and methods were calculated according to the MIRD concept or compiled from literature and were tabulated in conventional as well as in the SI-units recently introduced. The data are given for critical or investigated organs, ovaries, testes and red bone marrow. Where available, dose values for newborns, infants and children are included. Additionally, mean values of administered activity are listed. The manner in which to estimate the radiation dose to the patient is to multiply the tabulated dose values per unit administered activity with the corresponding mean or the actually administered activity. The methods are arranged in correlation with the following nuclear medical subspecialities: 1. Endocrinology 2. Neurology, 3. Osteomyology, 4. Gastroenterology, 5. Nephrology, 6. Pulmonology, 7. Hematology, 8. Cardiology/Angiology.

  11. Non-targeted effects of radiation: applications for radiation protection and contribution to LNT discussion

    International Nuclear Information System (INIS)

    Belyakov, O.V.; Folkard, M.; Prise, K.M.; Michael, B.D.; Mothersill, C.

    2002-01-01

    According to the target theory of radiation induced effects (Lea, 1946), which forms a central core of radiation biology, DNA damage occurs during or very shortly after irradiation of the nuclei in targeted cells and the potential for biological consequences can be expressed within one or two cell generations. A range of evidence has now emerged that challenges the classical effects resulting from targeted damage to DNA. These effects have also been termed non-(DNA)-targeted (Ward, 1999) and include radiation-induced bystander effects (Iyer and Lehnert, 2000a), genomic instability (Wright, 2000), adaptive response (Wolff, 1998), low dose hyper-radiosensitivity (HRS) (Joiner, et al., 2001), delayed reproductive death (Seymour, et al., 1986) and induction of genes by radiation (Hickman, et al., 1994). An essential feature of non-targeted effects is that they do not require a direct nuclear exposure by irradiation to be expressed and they are particularly significant at low doses. This new evidence suggests a new paradigm for radiation biology that challenges the universality of target theory. In this paper we will concentrate on the radiation-induced bystander effects because of its particular importance for radiation protection

  12. Radiation dose measurements in intravenous pyelography

    International Nuclear Information System (INIS)

    Egeblad, M.; Gottlieb, E.

    1975-01-01

    Intravenous pyelography (IVP) and micturition cystourethrography (MCU) are the standard procedures in the radiological examination of children with urinary tract infections and in the control of these children. Gonad protection against radiation is not possible in MCU, but concerning the girls partly possible in IVP. It is of major importance to know the radiation dose in these procedures, especially since the examination is often repeated in the same patients. All IVP were done by means of the usual technique including possible gonad protection. The thermoluminescence dosimeter was placed rectally in the girls and fixed on the scrota in the boys. A total of 50 children was studied. Gonad dose ranged from 140 to 200mR in the girls and from 20 to 70mR in the boys (mean values). The radiation dose in IVP is very low compared to that of MCU, and from this point of view IVP is a dose saving examination in the control of children with urinary tract infections [fr

  13. Radiation doses in endoscopic interventional procedures

    International Nuclear Information System (INIS)

    Tsapaki, V.; Paraskeva, K.; Mathou, N.; Aggelogiannopoulou, P.; Triantopoulou, C.; Karagianis, J.; Giannakopoulos, A.; Paspatis, G.; Voudoukis, E.; Athanasopoulos, N.; Lydakis, I.; Scotiniotis, H.; Georgopoulos, P.; Finou, P.; Kadiloru, E.

    2012-01-01

    Purpose: Extensive literature exists on patient radiation doses in various interventional procedures. This does not stand for endoscopic retrograde cholangiopancreatography (ERCP) where the literature is very limited. This study compares patient dose during ERCP procedures performed with different types of X-ray systems. Methods and Materials: Four hospitals participated in the study with the following X-ray systems: A) X-ray conventional system (X-ray tube over table), 137 pts, B) X-ray conventional system (X-ray tube under table), 114 pts, C) C-arm system, 79 pts, and D) angiography system, 57 pts. A single experienced endoscopist performed the ERCP in each hospital. Kerma Area Product (KAP), fluoroscopy time (T) and total number of X-ray films (F) were collected. Results: Median patient dose was 6.2 Gy.cm 2 (0.02-130.2 Gy.cm 2 ). Medium linear correlation between KAP and T (0.6) and F (0.4) were observed. Patient doses were 33 % higher than the reference value in UK (4.15 Gy.cm 2 with a sample of 6089 patients). Median KAP for each hospital was: A) 3.1, B) 9.2, C) 3.9 and D) 6.2 Gy.cm 2 . Median T was: A) 2.6, B) 4.1, C) 2.8 and D) 3.4 min. Median F was: A) 2, B) 7, C) 2 and D) 2 films. Conclusion: Patient radiation dose during ERCP depends on: a) fluoroscopy time and films taken, b) the type of the X-ray system used, with the C arm and the conventional over the couch systems carrying the lower patient radiation dose and the angiography system the higher. (authors)

  14. Internal 40K radiation dose to Indians

    International Nuclear Information System (INIS)

    Ranganathan, S.; Someswara Rao, M.; Nagaratnam, A.; Mishra, U.C.

    2002-01-01

    A group of 350 Indians from both sexes (7-65 years) representing different regions of India was studied for internal 40 K radiation dose from the naturally occurring body 40 K, which was measured in the National Institute of Nutrition (NIN) whole-body counter. Although the 40 K radioactivity reached a peak value by 18 years in female (2,412 Bq) and by 20 years in male (3,058 Bq) and then varied inversely with age in both sexes, the radiation dose did not show such a trend. Boys and girls of 11 years had annual effective dose of nearly 185 mSv, which decreased during adolescence (165 mSv), increased to 175 mSv by 18-20 years in adults and decreased progressively on further ageing to 99 mSv in males and 69 mSv in females at 65 years. The observed annual effective dose (175 mSv) of the young adults was close to that of the ICRP Reference Man (176 mSv) and Indian Reference Man (175 mSv). With a mean specific activity of 55 Bq/kg for the subjects and a conversion coefficient close to 3 mSv per annum per Bq/kg, the average annual effective dose from the internal 40 K turned out to be 165 mSv for Indians. (author)

  15. Patient radiation dose during mammography procedures

    International Nuclear Information System (INIS)

    Mohamed, Swsan Awd Elkriem

    2015-11-01

    The objectives of this study were to estimate the patient dose in term of mean glandular dose and assist in optimization of radiation protection in mammographic procedures in Sudan. A total number of 107 patients were included. Four mammographic units were participated. Only one center was using automatic exposure control (AEC). The mean doses in (mGy) for the CC projection were 3.13, 1.24, 2.45 and 0.98 and for the MLO projection was 2.13, 1.26, 1.99 and 1.02 for centers A, B, C, and D, respectively. The total mean dose per breast from both projections was 5.26, 2.50, 4.44 and 1.99 mGy for centers A, B, C and D, respectively. The minimum mean glandular dose was found between the digital system which was operated under AEC and one of the manual selected exposure factors systems, this highlight possible optimization of radiation protection in the other manual selected systems. The kilo volt and the tube current time products should be selected correctly according to the breast thickness in both centers A and C. (author)

  16. Agriculture-related radiation dose calculations

    International Nuclear Information System (INIS)

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

    1987-10-01

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

  17. Radiation doses to patients at dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    Paulusson-Odenhagen, M

    1975-11-01

    An investigation about the technique and the equipment at x-ray investigations and the distribution of the radiation doses to the thyroid and the gonads has been made in the dental policlinics belonging to the county council of the province of Stockholm. This investigation, which was suggested by the National Institute of Radiation Protection and the faculty of odontology in Stockholm, consisted of on one hand a distributed questionnaire and on the other visits. The questionnaire was distributed to all dentists (altogether 343) belonging to the dental policlinics of the county council of the province of Stockholm. 22 dentists of these were visited.

  18. Plenary panel 1: The scientific bases of radiation protection. Non-targeted effects of ionising radiation - Implications for radiation protection

    International Nuclear Information System (INIS)

    Salomaa, S.

    2006-01-01

    The universality of the target theory of radiation-induced effects is challenged by observations on non-targeted effects such as bystander effects, genomic instability and adaptive response. Essential features of non-targeted effects are that they do not require direct nuclear exposure by radiation and they are particularly significant at low doses. This new evidence suggests a need for a new paradigm in radiation biology. The new paradigm should cover both the classical (targeted) and the non-targeted effects. New aspects include the role of cellular communication and tissue-level responses. A better understanding of non-targeted effects may have important consequences for health risk assessment and, consequently, on radiation protection. Non-targeted effects may contribute to the estimation of cancer risk from occupational, medical and environmental exposures. In particular, they may have implications for the applicability of the Linear-No-Threshold (L.N.T.) model in extrapolating radiation risk data into the low-dose region. This also means that the adequacy of the concept of dose to estimate risk is challenged by these findings. Moreover, these effects may provide new mechanistic explanations for the development of non-cancer diseases. Further research is required to determine if these effects, typically measured in cell cultures, are applicable in tissue level, whole animals, and ultimately in humans. (authors)

  19. Plenary panel 1: The scientific bases of radiation protection. Non-targeted effects of ionising radiation - Implications for radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Salomaa, S. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland)

    2006-07-01

    The universality of the target theory of radiation-induced effects is challenged by observations on non-targeted effects such as bystander effects, genomic instability and adaptive response. Essential features of non-targeted effects are that they do not require direct nuclear exposure by radiation and they are particularly significant at low doses. This new evidence suggests a need for a new paradigm in radiation biology. The new paradigm should cover both the classical (targeted) and the non-targeted effects. New aspects include the role of cellular communication and tissue-level responses. A better understanding of non-targeted effects may have important consequences for health risk assessment and, consequently, on radiation protection. Non-targeted effects may contribute to the estimation of cancer risk from occupational, medical and environmental exposures. In particular, they may have implications for the applicability of the Linear-No-Threshold (L.N.T.) model in extrapolating radiation risk data into the low-dose region. This also means that the adequacy of the concept of dose to estimate risk is challenged by these findings. Moreover, these effects may provide new mechanistic explanations for the development of non-cancer diseases. Further research is required to determine if these effects, typically measured in cell cultures, are applicable in tissue level, whole animals, and ultimately in humans. (authors)

  20. Experimentally studied dynamic dose interplay does not meaningfully affect target dose in VMAT SBRT lung treatments.

    Science.gov (United States)

    Stambaugh, Cassandra; Nelms, Benjamin E; Dilling, Thomas; Stevens, Craig; Latifi, Kujtim; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir

    2013-09-01

    The effects of respiratory motion on the tumor dose can be divided into the gradient and interplay effects. While the interplay effect is likely to average out over a large number of fractions, it may play a role in hypofractionated [stereotactic body radiation therapy (SBRT)] treatments. This subject has been extensively studied for intensity modulated radiation therapy but less so for volumetric modulated arc therapy (VMAT), particularly in application to hypofractionated regimens. Also, no experimental study has provided full four-dimensional (4D) dose reconstruction in this scenario. The authors demonstrate how a recently described motion perturbation method, with full 4D dose reconstruction, is applied to describe the gradient and interplay effects during VMAT lung SBRT treatments. VMAT dose delivered to a moving target in a patient can be reconstructed by applying perturbations to the treatment planning system-calculated static 3D dose. Ten SBRT patients treated with 6 MV VMAT beams in five fractions were selected. The target motion (motion kernel) was approximated by 3D rigid body translation, with the tumor centroids defined on the ten phases of the 4DCT. The motion was assumed to be periodic, with the period T being an average from the empirical 4DCT respiratory trace. The real observed tumor motion (total displacement ≤ 8 mm) was evaluated first. Then, the motion range was artificially increased to 2 or 3 cm. Finally, T was increased to 60 s. While not realistic, making T comparable to the delivery time elucidates if the interplay effect can be observed. For a single fraction, the authors quantified the interplay effect as the maximum difference in the target dosimetric indices, most importantly the near-minimum dose (D99%), between all possible starting phases. For the three- and five-fractions, statistical simulations were performed when substantial interplay was found. For the motion amplitudes and periods obtained from the 4DCT, the interplay effect

  1. Experimentally studied dynamic dose interplay does not meaningfully affect target dose in VMAT SBRT lung treatments

    International Nuclear Information System (INIS)

    Stambaugh, Cassandra; Nelms, Benjamin E.; Dilling, Thomas; Stevens, Craig; Latifi, Kujtim; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir

    2013-01-01

    Purpose: The effects of respiratory motion on the tumor dose can be divided into the gradient and interplay effects. While the interplay effect is likely to average out over a large number of fractions, it may play a role in hypofractionated [stereotactic body radiation therapy (SBRT)] treatments. This subject has been extensively studied for intensity modulated radiation therapy but less so for volumetric modulated arc therapy (VMAT), particularly in application to hypofractionated regimens. Also, no experimental study has provided full four-dimensional (4D) dose reconstruction in this scenario. The authors demonstrate how a recently described motion perturbation method, with full 4D dose reconstruction, is applied to describe the gradient and interplay effects during VMAT lung SBRT treatments.Methods: VMAT dose delivered to a moving target in a patient can be reconstructed by applying perturbations to the treatment planning system-calculated static 3D dose. Ten SBRT patients treated with 6 MV VMAT beams in five fractions were selected. The target motion (motion kernel) was approximated by 3D rigid body translation, with the tumor centroids defined on the ten phases of the 4DCT. The motion was assumed to be periodic, with the period T being an average from the empirical 4DCT respiratory trace. The real observed tumor motion (total displacement ≤8 mm) was evaluated first. Then, the motion range was artificially increased to 2 or 3 cm. Finally, T was increased to 60 s. While not realistic, making T comparable to the delivery time elucidates if the interplay effect can be observed. For a single fraction, the authors quantified the interplay effect as the maximum difference in the target dosimetric indices, most importantly the near-minimum dose (D 99% ), between all possible starting phases. For the three- and five-fractions, statistical simulations were performed when substantial interplay was found.Results: For the motion amplitudes and periods obtained from the

  2. Wound trauma alters ionizing radiation dose assessment

    Directory of Open Access Journals (Sweden)

    Kiang Juliann G

    2012-06-01

    Full Text Available Abstract Background Wounding following whole-body γ-irradiation (radiation combined injury, RCI increases mortality. Wounding-induced increases in radiation mortality are triggered by sustained activation of inducible nitric oxide synthase pathways, persistent alteration of cytokine homeostasis, and increased susceptibility to bacterial infection. Among these factors, cytokines along with other biomarkers have been adopted for biodosimetric evaluation and assessment of radiation dose and injury. Therefore, wounding could complicate biodosimetric assessments. Results In this report, such confounding effects were addressed. Mice were given 60Co γ-photon radiation followed by skin wounding. Wound trauma exacerbated radiation-induced mortality, body-weight loss, and wound healing. Analyses of DNA damage in bone-marrow cells and peripheral blood mononuclear cells (PBMCs, changes in hematology and cytokine profiles, and fundamental clinical signs were evaluated. Early biomarkers (1 d after RCI vs. irradiation alone included significant decreases in survivin expression in bone marrow cells, enhanced increases in γ-H2AX formation in Lin+ bone marrow cells, enhanced increases in IL-1β, IL-6, IL-8, and G-CSF concentrations in blood, and concomitant decreases in γ-H2AX formation in PBMCs and decreases in numbers of splenocytes, lymphocytes, and neutrophils. Intermediate biomarkers (7 – 10 d after RCI included continuously decreased γ-H2AX formation in PBMC and enhanced increases in IL-1β, IL-6, IL-8, and G-CSF concentrations in blood. The clinical signs evaluated after RCI were increased water consumption, decreased body weight, and decreased wound healing rate and survival rate. Late clinical signs (30 d after RCI included poor survival and wound healing. Conclusion Results suggest that confounding factors such as wounding alters ionizing radiation dose assessment and agents inhibiting these responses may prove therapeutic for radiation combined

  3. Lowering the Radiation Dose in Dental Offices.

    Science.gov (United States)

    Radan, Elham

    2017-04-01

    While the use of dental imaging continues to evolve into more advanced modalities such as 3-D cone beam computed tomography, in addition to conventional 2-D imaging (intraoral, panoramic and cephalometric), the public concern for radiation safety is also increasing. This article is a guide for how to reduce patients’ exposure to the minimum with proper selection criteria (as needed only if it benefits the patient) and knowledge of effective doses, exposure parameters and proper collimation.

  4. New technologies to reduce pediatric radiation doses

    International Nuclear Information System (INIS)

    Bernhardt, Philipp; Lendl, Markus; Deinzer, Frank

    2006-01-01

    X-ray dose reduction in pediatrics is particularly important because babies and children are very sensitive to radiation exposure. We present new developments to further decrease pediatric patient dose. With the help of an advanced exposure control, a constant image quality can be maintained for all patient sizes, leading to dose savings for babies and children of up to 30%. Because objects of interest are quite small and the speed of motion is high in pediatric patients, short pulse widths down to 4 ms are important to reduce motion blurring artifacts. Further, a new noise-reduction algorithm is presented that detects and processes signal and noise in different frequency bands, generating smooth images without contrast loss. Finally, we introduce a super-resolution technique: two or more medical images, which are shifted against each other in a subpixel region, are combined to resolve structures smaller than the size of a single pixel. Advanced exposure control, short exposure times, noise reduction and super-resolution provide improved image quality, which can also be invested to save radiation exposure. All in all, the tools presented here offer a large potential to minimize the deterministic and stochastic risks of radiation exposure. (orig.)

  5. Radiation Dose to Post-Chernobyl Cleanup Workers

    Science.gov (United States)

    Radiation dose calculation for post-Chernobyl Cleanup Workers in Ukraine - both external radiation exposure due to fallout and internal doses due to inhalation (I131 intake) or ingestion of contaminated foodstuffs.

  6. Audit of radiation dose to patients during coronary angiography

    International Nuclear Information System (INIS)

    Livingstone, Roshan S.; Chandy, Sunil; Peace, Timothy B.S.; George, Paul V.; John, Bobby; Pati, Purendra

    2007-01-01

    There is a widespread concern about radiation doses imparted to patients during cardiology procedures in the medical community. The current study intends to audit and optimize radiation dose to patients undergoing coronary angiography performed using two dedicated cardiovascular machines

  7. 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)

  8. Low radiation doses - Book of presentations (slides)

    International Nuclear Information System (INIS)

    2013-03-01

    This document brings together all the available presentations (slides) of the conference on low radiation doses organised by the 'research and health' department of the French society of radiation protection (SFRP). Ten presentations are available and deal with he following topics: 1 - Cyto-toxicity, geno-toxicity: comparative approach between ionizing radiations and other geno-toxic agents (F. Nesslany, Institut Pasteur, Lille); Succession of events occurring after a radio-induced DNA damage (D. Averbeck, IRSN/CEA); Importance of stem cells in the response to ionizing radiations (J. Lebeau, CEA); Relation between energy deposition at the sub-cell scale and early biological effects (C. Villagrasa, IRSN); Natural history of breast cancer: predisposition, susceptibility with respect to irradiation (S. Rivera, IGR); Pediatrics scanner study and the EPI-CT project (M.O Bernier, IRSN); What future for an irradiated cell: survival or apoptosis? (E. Sage, Institut Curie); Differential effect of a 137 Cs chronic contamination on the different steps of the atheromatous pathology (T. Ebrahimian, IRSN); Variability of the individual radiosensitivity (S. Chevillard, CEA); What definitions for individual sensitivity? (A. Schmidt, CEA); Low doses: some philosophical remarks (A. Grinbaum, CEA)

  9. Low doses effects of ionizing radiation on Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Durand, J.; Broock, M. van; Gillette, V.H.

    2000-01-01

    The exposure of living cells to low doses of ionizing radiation induce in response the activation of cellular protection mechanisms against subsequent larger doses of radiation. This cellular adaptive response may vary depending on radiation intensity and time of exposure, and also on the testing probes used whether they were mammalian cells, yeast, bacteria and other organisms or cell types. The mechanisms involved are the genome activation, followed by DNA repair enzymes synthesis. Due to the prompt cell response, the cell cycle can be delayed, and the secondary detoxification of free radicals and/or activation of membrane bound receptors may proceed. All these phenomena are submitted to intense scientific research nowadays, and their elucidation will depend on the complexity of the organism under study. In the present work, the effects of low doses of ionizing radiation (gamma rays) over a suspension of the yeast Saccharomyces cerevisiae (Baker's yeast) was studied, mainly in respect to survival rate and radio-adaptive response. At first, the yeast surviving curve was assessed towards increasing doses, and an estimation of Lethal Dose 50 (LD50) was made. The irradiation tests were performed at LINAC (electrons Linear Accelerator) where electron energy reached approximately 2.65 MeV, and gamma-radiation was produced for bremsstrahlung process over an aluminium screen target. A series of experiments of conditioning doses was performed and an increment surviving fraction was observed when the dose was 2.3 Gy and a interval time between this and a higher dose (challenging dose) of 27 Gy was 90 minutes. A value of 58 ± 4 Gy was estimated for LD50, at a dose rate of 0.44 ± 0.03 Gy/min These quantities must be optimized. Besides data obtained over yeast survival, an unusual increasing amount of tiny yeast colonies appeared on the agar plates after incubation, and this number increased as increasing the time exposure. Preliminary results indicate these colonies as

  10. Annual individual doses for personnel dealing with ionizing radiation sources

    International Nuclear Information System (INIS)

    Poplavskij, K.K.

    1982-01-01

    Data on annual individual doses for personnel of national economy enterprises, research institutes, high schools, medical establishments dealing with ionizing radiation sources are presented. It is shown that radiation dose for the personnel constitutes only shares of standards established by sanitary legislation. Numeral values of individual doses of the personnel are determined by the type, character and scope of using ionizing radiation sources

  11. Use of EORTC Target Definition Guidelines for Dose-Intensified Salvage Radiation Therapy for Recurrent Prostate Cancer: Results of the Quality Assurance Program of the Randomized Trial SAKK 09/10

    International Nuclear Information System (INIS)

    Sassowsky, Manfred; Gut, Philipp; Hölscher, Tobias; Hildebrandt, Guido; Müller, Arndt-Christian; Najafi, Yousef; Kohler, Götz; Kranzbühler, Helmut; Guckenberger, Matthias; Zwahlen, Daniel R.; Azinwi, Ngwa C.; Plasswilm, Ludwig; Takacs, Istvan; Reuter, Christiane; Sumila, Marcin; Manser, Peter; Ost, Piet; Böhmer, Dirk; Pilop, Christiane; Aebersold, Daniel M.

    2013-01-01

    Purpose: Different international target volume delineation guidelines exist and different treatment techniques are available for salvage radiation therapy (RT) for recurrent prostate cancer, but less is known regarding their respective applicability in clinical practice. Methods and Materials: A randomized phase III trial testing 64 Gy vs 70 Gy salvage RT was accompanied by an intense quality assurance program including a site-specific and study-specific questionnaire and a dummy run (DR). Target volume delineation was performed according to the European Organisation for the Research and Treatment of Cancer guidelines, and a DR-based treatment plan was established for 70 Gy. Major and minor protocol deviations were noted, interobserver agreement of delineated target contours was assessed, and dose-volume histogram (DVH) parameters of different treatment techniques were compared. Results: Thirty European centers participated, 43% of which were using 3-dimensional conformal RT (3D-CRT), with the remaining centers using intensity modulated RT (IMRT) or volumetric modulated arc technique (VMAT). The first submitted version of the DR contained major deviations in 21 of 30 (70%) centers, mostly caused by inappropriately defined or lack of prostate bed (PB). All but 5 centers completed the DR successfully with their second submitted version. The interobserver agreement of the PB was moderate and was improved by the DR review, as indicated by an increased κ value (0.59 vs 0.55), mean sensitivity (0.64 vs 0.58), volume of total agreement (3.9 vs 3.3 cm 3 ), and decrease in the union volume (79.3 vs 84.2 cm 3 ). Rectal and bladder wall DVH parameters of IMRT and VMAT vs 3D-CRT plans were not significantly different. Conclusions: The interobserver agreement of PB delineation was moderate but was improved by the DR. Major deviations could be identified for the majority of centers. The DR has improved the acquaintance of the participating centers with the trial protocol

  12. Use of EORTC Target Definition Guidelines for Dose-Intensified Salvage Radiation Therapy for Recurrent Prostate Cancer: Results of the Quality Assurance Program of the Randomized Trial SAKK 09/10

    Energy Technology Data Exchange (ETDEWEB)

    Sassowsky, Manfred [Department of Radiation Oncology and Division of Medical Radiation Physics, Bern University Hospital (Switzerland); Gut, Philipp [Department of Radiation Oncology Kantonsspital Luzern (Switzerland); Hölscher, Tobias [University Hospital Dresden (Germany); Hildebrandt, Guido [University Hospital Rostock (Germany); Müller, Arndt-Christian [University Hospital Tübingen (Germany); Najafi, Yousef [University Hospital Zürich (Switzerland); Kohler, Götz [University Hospital Basel (Switzerland); Kranzbühler, Helmut [Stadtspital Triemli, Zürich (Switzerland); Guckenberger, Matthias [University Hospital Würzburg (Germany); Zwahlen, Daniel R. [Kantonsspital Graubünden, Chur (Switzerland); Azinwi, Ngwa C. [Istituto Oncologico della Svizzera Italiana, Bellinzona (Switzerland); Plasswilm, Ludwig [Kantonsspital St. Gallen (Switzerland); Takacs, Istvan [Kantonsspital Aarau (Switzerland); Reuter, Christiane [Kantonsspital Münsterlingen (Switzerland); Sumila, Marcin [Hirslanden Hospital Group, Zürich (Switzerland); Manser, Peter [Department of Radiation Oncology and Division of Medical Radiation Physics, Bern University Hospital (Switzerland); Ost, Piet [Ghent University Hospital (Belgium); Böhmer, Dirk [Charité University Medicine, Berlin (Germany); Pilop, Christiane [Swiss Group for Clinical Cancer Research, Coordinating Center, Bern (Switzerland); Aebersold, Daniel M. [Department of Radiation Oncology and Division of Medical Radiation Physics, Bern University Hospital (Switzerland); and others

    2013-11-01

    Purpose: Different international target volume delineation guidelines exist and different treatment techniques are available for salvage radiation therapy (RT) for recurrent prostate cancer, but less is known regarding their respective applicability in clinical practice. Methods and Materials: A randomized phase III trial testing 64 Gy vs 70 Gy salvage RT was accompanied by an intense quality assurance program including a site-specific and study-specific questionnaire and a dummy run (DR). Target volume delineation was performed according to the European Organisation for the Research and Treatment of Cancer guidelines, and a DR-based treatment plan was established for 70 Gy. Major and minor protocol deviations were noted, interobserver agreement of delineated target contours was assessed, and dose-volume histogram (DVH) parameters of different treatment techniques were compared. Results: Thirty European centers participated, 43% of which were using 3-dimensional conformal RT (3D-CRT), with the remaining centers using intensity modulated RT (IMRT) or volumetric modulated arc technique (VMAT). The first submitted version of the DR contained major deviations in 21 of 30 (70%) centers, mostly caused by inappropriately defined or lack of prostate bed (PB). All but 5 centers completed the DR successfully with their second submitted version. The interobserver agreement of the PB was moderate and was improved by the DR review, as indicated by an increased κ value (0.59 vs 0.55), mean sensitivity (0.64 vs 0.58), volume of total agreement (3.9 vs 3.3 cm{sup 3}), and decrease in the union volume (79.3 vs 84.2 cm{sup 3}). Rectal and bladder wall DVH parameters of IMRT and VMAT vs 3D-CRT plans were not significantly different. Conclusions: The interobserver agreement of PB delineation was moderate but was improved by the DR. Major deviations could be identified for the majority of centers. The DR has improved the acquaintance of the participating centers with the trial

  13. Internal radiation dose calculations with the INREM II computer code

    International Nuclear Information System (INIS)

    Dunning, D.E. Jr.; Killough, G.G.

    1978-01-01

    A computer code, INREM II, was developed to calculate the internal radiation dose equivalent to organs of man which results from the intake of a radionuclide by inhalation or ingestion. Deposition and removal of radioactivity from the respiratory tract is represented by the Internal Commission on Radiological Protection Task Group Lung Model. A four-segment catenary model of the gastrointestinal tract is used to estimate movement of radioactive material that is ingested, or swallowed after being cleared from the respiratory tract. Retention of radioactivity in other organs is specified by linear combinations of decaying exponential functions. The formation and decay of radioactive daughters is treated explicitly, with each radionuclide in the decay chain having its own uptake and retention parameters, as supplied by the user. The dose equivalent to a target organ is computed as the sum of contributions from each source organ in which radioactivity is assumed to be situated. This calculation utilizes a matrix of dosimetric S-factors (rem/μCi-day) supplied by the user for the particular choice of source and target organs. Output permits the evaluation of components of dose from cross-irradiations when penetrating radiations are present. INREM II has been utilized with current radioactive decay data and metabolic models to produce extensive tabulations of dose conversion factors for a reference adult for approximately 150 radionuclides of interest in environmental assessments of light-water-reactor fuel cycles. These dose conversion factors represent the 50-year dose commitment per microcurie intake of a given radionuclide for 22target organs including contributions from specified source organs and surplus activity in the rest of the body. These tabulations are particularly significant in their consistent use of contemporary models and data and in the detail of documentation

  14. Radiation dose in radiotherapy from prescription to delivery

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    Cancer incidence is increasing in developed as well as in developing countries. Cancer may be expected to become a prominent problem and this will result in public pressure for higher priorities on cancer care. In some relatively advanced developing countries radiation therapy is applied in about 50% of all detected cancer cases. Approximately half of these treatments have curative intent. Surgery and radiotherapy applied individually or combined result in the cure of about 40% of all patients. The application of chemotherapy alone has curative effects only on a small percentage of cancer patients. It is encouraging to note that the results achieved by radiation therapy show continuous improvement. This can be traced back to a number of developments: increased knowledge regarding tumour and normal tissue response to radiation, early diagnosis with improved tumour localisation, improved dosimetry and dose planning. The introduction of modern equipment has been crucial in these developments and makes possible a more accurate target delineation, better treatment planning resulting in irradiation of the Planning Target Volume (PTV) with a highly uniform dose and, simultaneously, a reduction in dose to healthy tissues outside the PTV. Experience shows that high quality radiotherapy can only be achieved if its conducted by a skilled team working closely together with good communication between various categories of staff. Therefore, seminars and training courses covering all aspects of radiotherapy and dosimetry are of great importance and should be held regionally or nationally on a regular basis. Refs, figs, tabs.

  15. Radiation dose in radiotherapy from prescription to delivery

    International Nuclear Information System (INIS)

    1996-08-01

    Cancer incidence is increasing in developed as well as in developing countries. Cancer may be expected to become a prominent problem and this will result in public pressure for higher priorities on cancer care. In some relatively advanced developing countries radiation therapy is applied in about 50% of all detected cancer cases. Approximately half of these treatments have curative intent. Surgery and radiotherapy applied individually or combined result in the cure of about 40% of all patients. The application of chemotherapy alone has curative effects only on a small percentage of cancer patients. It is encouraging to note that the results achieved by radiation therapy show continuous improvement. This can be traced back to a number of developments: increased knowledge regarding tumour and normal tissue response to radiation, early diagnosis with improved tumour localisation, improved dosimetry and dose planning. The introduction of modern equipment has been crucial in these developments and makes possible a more accurate target delineation, better treatment planning resulting in irradiation of the Planning Target Volume (PTV) with a highly uniform dose and, simultaneously, a reduction in dose to healthy tissues outside the PTV. Experience shows that high quality radiotherapy can only be achieved if its conducted by a skilled team working closely together with good communication between various categories of staff. Therefore, seminars and training courses covering all aspects of radiotherapy and dosimetry are of great importance and should be held regionally or nationally on a regular basis. Refs, figs, tabs

  16. Targeted and non-targeted effects of ionizing radiation

    Directory of Open Access Journals (Sweden)

    Omar Desouky

    2015-04-01

    Full Text Available For a long time it was generally accepted that effects of ionizing radiation such as cell death, chromosomal aberrations, DNA damage, mutagenesis, and carcinogenesis result from direct ionization of cell structures, particularly DNA, or from indirect damage through reactive oxygen species produced by radiolysis of water, and these biological effects were attributed to irreparable or misrepaired DNA damage in cells directly hit by radiation. Using linear non-threshold model (LNT, possible risks from exposure to low dose ionizing radiation (below 100 mSv are estimated by extrapolating from data obtained after exposure to higher doses of radiation. This model has been challenged by numerous observations, in which cells that were not directly traversed by the ionizing radiation exhibited responses similar to those of the directly irradiated cells. Therefore, it is nowadays accepted that the detrimental effects of ionizing radiation are not restricted only in the irradiated cells, but also to non-irradiated bystander or even distant cells manifesting various biological effects.

  17. Low Dose Ionizing Radiation Modulates Immune Function

    International Nuclear Information System (INIS)

    Nelson, Gregory A.

    2016-01-01

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a 'Th2 polarized' immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in

  18. Low Dose Ionizing Radiation Modulates Immune Function

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-12

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

  19. Ultraviolet radiation therapy and UVR dose models

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, David Robert, E-mail: davidrobert.grimes@oncology.ox.ac.uk [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland and Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratory, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ (United Kingdom)

    2015-01-15

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

  20. Ultraviolet radiation therapy and UVR dose models

    International Nuclear Information System (INIS)

    Grimes, David Robert

    2015-01-01

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

  1. Radiation dose to the eye lens

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  2. Use of a concise prescription for specifying absolute dose distribution in external beam radiation therapy

    International Nuclear Information System (INIS)

    Viggers, D.A.; Shalev, S.

    1989-01-01

    Radiation therapy dose distributions are usually calculated relative to some normalization point to which a prescribed dose in grays is to be delivered. Often the radiation therapist requests that the prescribed dose be delivered to some other point(s), such as the 90% isodose. Therefore the prescribed dose is not well defined. Furthermore, this procedure leaves the shape of the dose distribution unspecified. The authors have used a dose prescription specifying the volumes of target and nontarget tissue that must lie within dose limits stated in grays. These dose-volume limits determine the magnitude and shape of the dose distribution. The prescription is well defined while allowing the absolute dose at a chosen point to be adjusted so that the dose distribution satisfies the prescription

  3. Cells, targets, and molecules in radiation biology

    International Nuclear Information System (INIS)

    Elkind, M.M.

    1979-01-01

    Cellular damage and repair are discussed with regard to inactivation models, dose-effect curves and cancer research, repair relative to damage accumulation, potentially lethal damage, repair of potentially lethal vs. sublethal damage, cell killing and DNA damage due to nonionizing radiation, and anisotonicity vs. lethality due to nonionizing radiation. Other topics discussed are DNA damage and repair in cells exposed to ionizing radiation, kinetics of repair of single-strand DNA breaks, effects of actinomycin D on x-ray survival curve of hamster cells, misrepair and lethality, and perspective and prospects

  4. Comparison between dose values specified at the ICRU reference point and the mean dose to the planning target volume

    International Nuclear Information System (INIS)

    Kukoowicz, Pawel F.; Mijnheer, Bernard J.

    1997-01-01

    Background and purpose: To compare dose values specified at the reference point, as recommended by the International Commission on Radiation Units and Measurements, ICRU, and the mean dose to the planning target volume, PTV. Material and methods: CT-based dose calculations were performed with a 3-D treatment planning system for 6 series of patients treated for bladder, brain, breast, lung, oropharynx and parotid gland tumour. All patients were arbitrarily chosen from a set of previously treated patients irradiated with a two- or three-field technique using customised blocks. Appropriate wedge angles and beam weights were chosen to make the dose distribution as homogeneous as possible. Results: The dose at the ICRU reference point was generally higher than the mean dose to the PTV. The difference between the ICRU reference dose and the mean dose to the PTV for an individual patient was less than 3% in 88% of cases and less than 2% in 72% of the cases. The differences were larger in those patients where the dose distribution is significantly influenced by the presence of lungs or air gaps. For each series of patients the mean difference between the ICRU reference dose and the mean dose to the PTV was calculated. The difference between these two values never exceeded 2%. Because not all planning systems are able to calculate the mean dose to the PTV, the concept of the mean central dose, the mean of the dose values at the centre of the PTV in each CT slice, has been introduced. The mean central dose was also calculated for the same patients and was closer to the mean dose to the PTV than the ICRU reference dose. Conclusion: The mean dose to the PTV is well estimated by either the ICRU reference dose or the mean central dose for a variety of treatment techniques for common types of cancer

  5. 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

  6. Radiation doses to neonates requiring intensive care

    International Nuclear Information System (INIS)

    Robinson, A.; Dellagrammaticas, H.D.

    1983-01-01

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

  7. Radiation doses from mammography in Australia

    International Nuclear Information System (INIS)

    Thomson, J.E.M.; Young, B.F.; Young, J.G.; Tingey, D.R.C.

    1991-05-01

    During 1989-90 the Australian Radiation Laboratory conducted a postal survey of at least 90% of the mammographic facilities in Australia. The primary aim of the survey was to measure the mean glandular dose (MGD) and the X-ray beam half value layer (HVL) for a typical mammograph. The MGD and HVL were measured with a specially designed tissue equivalent monitor. In all, 258 mammographic centres were surveyed. It was found that for centres using film-screen imaging, the average mean glandular dose was 1.83 mGy for centres using grids and 0.84 mGy for centres not using grids. In addition to the MGD and HVL, comprehensive statistical information was collected and data is presented on the types of equipment and techniques used, the number and age of patients and demographic distribution of centres. Results indicate that the use of a grid is the major factor determining dose and several other factors appear to have minor effects. In view of the distribution of MGD, it is recommended that the mean glandular dose per image, for a 5 cm compressed breast thickness, should not exceed 2.0 mGy when a grid is used and 1.0 mGy without a grid. 63 refs., 11 tabs., 15 figs

  8. Radiation risk factors and dose limits

    International Nuclear Information System (INIS)

    Barendsen, G.W.

    1979-01-01

    The contents of the ICRP publications 9 (1965) and 26 (1977) are outlined and the research conducted during these years considered. Expressions are derived for the frequency for induction of cancer from the most common irradiations - X rays, gamma rays and electrons. The dose limits advised by the ICRP are discussed and the first two fundamental principles are presented - that no one should be subjected to radiation without useful cause and that in those cases where irradiation is thought necessary, the medical, scientific, social and economic advantages need to be carefully considered with respect to the possible disadvantages. (C.F.)

  9. Spine stereotactic body radiation therapy plans: Achieving dose coverage, conformity, and dose falloff

    International Nuclear Information System (INIS)

    Hong, Linda X.; Shankar, Viswanathan; Shen, Jin; Kuo, Hsiang-Chi; Mynampati, Dinesh; Yaparpalvi, Ravindra; Goddard, Lee; Basavatia, Amar; Fox, Jana; Garg, Madhur; Kalnicki, Shalom; Tomé, Wolfgang A.

    2015-01-01

    We report our experience of establishing planning objectives to achieve dose coverage, conformity, and dose falloff for spine stereotactic body radiation therapy (SBRT) plans. Patients with spine lesions were treated using SBRT in our institution since September 2009. Since September 2011, we established the following planning objectives for our SBRT spine plans in addition to the cord dose constraints: (1) dose coverage—prescription dose (PD) to cover at least 95% planning target volume (PTV) and 90% PD to cover at least 99% PTV; (2) conformity index (CI)—ratio of prescription isodose volume (PIV) to the PTV < 1.2; (3) dose falloff—ratio of 50% PIV to the PTV (R 50% ); (4) and maximum dose in percentage of PD at 2 cm from PTV in any direction (D 2cm ) to follow Radiation Therapy Oncology Group (RTOG) 0915. We have retrospectively reviewed 66 separate spine lesions treated between September 2009 and December 2012 (31 treated before September 2011 [group 1] and 35 treated after [group 2]). The χ 2 test was used to examine the difference in parameters between groups. The PTV V 100% PD ≥ 95% objective was met in 29.0% of group 1 vs 91.4% of group 2 (p < 0.01) plans. The PTV V 90% PD ≥ 99% objective was met in 38.7% of group 1 vs 88.6% of group 2 (p < 0.01) plans. Overall, 4 plans in group 1 had CI > 1.2 vs none in group 2 (p = 0.04). For D 2cm , 48.3% plans yielded a minor violation of the objectives and 16.1% a major violation for group 1, whereas 17.1% exhibited a minor violation and 2.9% a major violation for group 2 (p < 0.01). Spine SBRT plans can be improved on dose coverage, conformity, and dose falloff employing a combination of RTOG spine and lung SBRT protocol planning objectives

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

    Science.gov (United States)

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

    2017-12-01

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

  11. Targeted Radiation Therapy for Cancer Initiative

    Science.gov (United States)

    2017-11-01

    AWARD NUMBER: W81XWH-08-2-0174 TITLE: Targeted Radiation Therapy for Cancer Initiative PRINCIPAL INVESTIGATOR: Dusten Macdonald, MD...for Cancer Initiative 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dusten Macdonald, MD 5d. PROJECT NUMBER...Cancer Initiative Final Report INTRODUCTION: The full potential of radiation therapy has not been realized due to the inability to locate and

  12. Non-targeted and delayed effects of exposure to ionizing radiation

    International Nuclear Information System (INIS)

    Zuo Yahui; Tong Jian

    2007-01-01

    Non-targeted and delayed effects are relative phenomena in cellular responses to ionizing radiation. These effects (bystander effects, genomic instability and adaptive responses) have been studied most extensively for radiation exposures. It is clear that adaptive responses, bystander effects and genomic instability will play an important role in the low dose-response to radiation. This review will provide a synthesis of the known, and proposed interrelationships amongst low-dose cellular responses to radiation, It also will examine the potential biological significance of non-targeted and delayed effects of exposure to ionizing radiation. (authors)

  13. Biological effects of low-dose ionizing radiation exposure

    International Nuclear Information System (INIS)

    Reinoehl-Kompa, Sabine; Baldauf, Daniela; Heller, Horst

    2009-01-01

    The report on the meeting of the Strahlenschutzkommission 2007 concerning biological effects of low-dose ionizing radiation exposure includes the following contributions: Adaptive response. The importance of DNA damage mechanisms for the biological efficiency of low-energy photons. Radiation effects in mammography: the relative biological radiation effects of low-energy photons. Radiation-induced cataracts. Carcinomas following prenatal radiation exposure. Intercellular apoptosis induction and low-dose irradiation: possible consequences for the oncogenesis control. Mechanistic models for the carcinogenesis with radiation-induced cell inactivation: application to all solid tumors in the Japanese atomic bomb survivors. Microarrays at low radiation doses. Mouse models for the analysis of biological effects of low-dose ionizing radiation. The bystander effect: observations, mechanisms and implications. Lung carcinoma risk of Majak workers - modeling of carcinogenesis and the bystander effect. Microbeam studies in radiation biology - an overview. Carcinogenesis models with radiation-induced genomic instability. Application to two epidemiological cohorts.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

  15. Determination of the radiation dose to the body due to external radiation

    International Nuclear Information System (INIS)

    Drexler, G.; Eckerl, H.

    1985-01-01

    Section 63 of the Radiation Protection Ordinance defines the basic requirement, determination of radiation dose to the body. The determination of dose equivalents for the body is the basic step in practical monitoring of dose equivalents or dose limits with regard to individuals or population groups, both for constant or varying conditions of exposure. The main field of monitoring activities is the protection of persons occupationally exposed to ionizing radiation. Conversion factors between body doses and radiation quantities are explained. (DG) [de

  16. Ambient radioactivity levels and radiation doses. Annual report 2011

    International Nuclear Information System (INIS)

    Bernhard-Stroel, Claudia; Hachenburger, Claudia; Trugenberger-Schnabel, Angela; Peter, Josef

    2013-07-01

    The annual report 2011 on ambient radioactivity levels and radiation doses covers the following issues: Part A: Natural environmental radioactivity, artificial radioactivity in the environment, occupational radiation exposure, radiation exposure from medical applications, the handling of radioactive materials and sources of ionizing radiation, non-ionizing radiation. Part B; Current data and their evaluation: Natural environmental radioactivity, artificial radioactivity in the environment, occupational radiation exposure, radiation exposure from medical applications, the handling of radioactive materials and sources of ionizing radiation, non-ionizing radiation. The Appendix includes Explanations of terms, radiation doses and related units, external and internal radiation exposure, stochastic and deterministic radiation effects, genetic radiation effects, induction of malignant neoplasm, risk assessment, physical units and glossary, laws, ordinances, guidelines, recommendations and other regulations concerning radiation protection, list of selected radionuclides.

  17. Relationship to carcinogenesis of repetitive low-dose radiation exposure

    International Nuclear Information System (INIS)

    Ootsuyama, Akira

    2016-01-01

    We studied the carcinogenic effects caused by repetitive irradiation at a low dose, which has received attention in recent years, and examined the experimental methods used to evaluate radiation-induced carcinogenesis. For this experiment, we selected a mouse with as few autochthonous cancers as possible. Skin cancer was selected as the target for analysis, because it is a rare cancer in mice. Beta-rays were selected as the radiation source. The advantage of using beta-rays is weaker penetration power into tissues, thus protecting organs, such as the digestive and hematogenous organs. The benefit of our experimental method is that only skin cancer requires monitoring, and it is possible to perform long-term experiments. The back skin of mice was exposed repetitively to beta-rays three times a week until the occurrence of cancer or death, and the dose per exposure ranged from 0.5 to 11.8 Gy. With the high-dose range (2.5-11.8 Gy), the latency period and carcinogenic rate were almost the same in each experimental group. When the dose was reduced to 1-1.5 Gy, the latency period increased, but the carcinogenic rate remained. When the dose was further reduced to 0.5 Gy, skin cancer never happened, even though we continued irradiation until death of the last mouse in this group. The lifespan of 0.5 Gy group mice was the same as that of the controls. We showed that the 0.5 Gy dose did not cause cancer, even in mice exposed repetitively throughout their life span, and thus refer to 0.5 Gy as the threshold-like dose. (author)

  18. Analysis of CT radiation dose based on radiation-dose-structured reports

    International Nuclear Information System (INIS)

    Wang Weipeng; Zhang Yi; Zhang Menglong; Zhang Dapeng; Song Shaojuan

    2014-01-01

    Objective: To analyse the CT radiation dose statistically using the standardized radiation-dose-structured report (RDSR) of digital imaging and communications in medicine (DICOM). Methods: Using the self-designed software, 1230 RDSR files about CT examination were obtained searching on the picture archiving and communication system (PACS). The patient dose database was established by combination of the extracted relevant information with the scanned sites. The patients were divided into adult group (over 10 years) and child groups (0-1 year, 1-5 years, 5-10 years) according to the age. The average volume CT dose index (CTDI vol ) and dose length product (DLP) of all scans were recorded respectively, and then the effective dose (E) was estimated. The DLP value at 75% quantile was calculated and compared with the diagnostic reference level (DRL). Results: In adult group, CTDI vol and DLP values were moderately and positively correlated (r = 0.41), the highest E was observed in upper abdominal enhanced scan, and the DLP value at 75% quantile was 60% higher than DRL. In child group, their CTDI vol in group of 5-10 years was greater than that in groups of 0-1 and 1-5 years (t = 2.42, 2.04, P < 0.05); the DLP value was slightly and positively correlated with the age (r = 0.16), while E was moderately and negatively correlated with the age (r = -0.48). Conclusions: It is a simple and efficient method to use RDSR to obtain the radiation doses of patients. With the popularization of the new equipment and the application of regionalized medical platform, RDSR would become the main tool for the dosimetric level surveying and individual dose recording. (authors)

  19. Design of radiation dose tumor response assays

    International Nuclear Information System (INIS)

    Suit, H.D.; Hwang, T.; Hsieh, C.; Thames, H.

    1985-01-01

    The efficient utilization of animals in a radiation dose response assay for tumor control requires a definition of the goal, e.g., TCD50 or slope. A series of computer modelled ''experiments'' have been performed for each of a number of allocations of dose levels (DL) and number of animals/DL. The authors stipulated that the assumed TCD50 was .85 of true value; assumed slope was correct. They stipulated a binominal distribution of observed tumor control results at each dose level. A pilot assay used 6 tumors at 7 DL (from TCD1-TCD97). The second assay used 30 tumors assigned to 2,3,5 or 9 DL and to selected tumor control probabilities (TCP derived from the pilot run. Results from 100 test runs were combined with the pilot run for each of the combination of DL and TCP values. Logit regression lines were fitted through these ''data'' and the 95% CL around the TCD50 and the TCD37 values and the variances of the slopes were computed. These experiments were repeated using the method suggested by Porter (1980). Results show that a different strategy is needed depending upon the goal, viz. TCD50 or TCD37 vs slope. The differences between the two approaches are discussed

  20. Cumulative radiation dose of multiple trauma patients during their hospitalization

    International Nuclear Information System (INIS)

    Wang Zhikang; Sun Jianzhong; Zhao Zudan

    2012-01-01

    Objective: To study the cumulative radiation dose of multiple trauma patients during their hospitalization and to analyze the dose influence factors. Methods: The DLP for CT and DR were retrospectively collected from the patients during June, 2009 and April, 2011 at a university affiliated hospital. The cumulative radiation doses were calculated by summing typical effective doses of the anatomic regions scanned. Results: The cumulative radiation doses of 113 patients were collected. The maximum,minimum and the mean values of cumulative effective doses were 153.3, 16.48 mSv and (52.3 ± 26.6) mSv. Conclusions: Multiple trauma patients have high cumulative radiation exposure. Therefore, the management of cumulative radiation doses should be enhanced. To establish the individualized radiation exposure archives will be helpful for the clinicians and technicians to make decision whether to image again and how to select the imaging parameters. (authors)

  1. Radiation dose-reduction strategies in thoracic CT.

    Science.gov (United States)

    Moser, J B; Sheard, S L; Edyvean, S; Vlahos, I

    2017-05-01

    Modern computed tomography (CT) machines have the capability to perform thoracic CT for a range of clinical indications at increasingly low radiation doses. This article reviews several factors, both technical and patient-related, that can affect radiation dose and discusses current dose-reduction methods relevant to thoracic imaging through a review of current techniques in CT acquisition and image reconstruction. The fine balance between low radiation dose and high image quality is considered throughout, with an emphasis on obtaining diagnostic quality imaging at the lowest achievable radiation dose. The risks of excessive radiation dose reduction are also considered. Inappropriately low dose may result in suboptimal or non-diagnostic imaging that may reduce diagnostic confidence, impair diagnosis, or result in repeat examinations incurring incremental ionising radiation exposure. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  2. Dose effect relationships in cervical and thoracic radiation myelopathies

    International Nuclear Information System (INIS)

    Holdorff, B.

    1980-01-01

    The course and prognosis of radiation myelopathies are determined by 3 factors: the segmental (vertical) location of the lesion, the extent of the transverse syndrome (complete or incomplete) and the radiation dose. The median spinal dose in cervical radiation myelopathies with fatal outcome was higher than in survivals with an incomplete transverse syndrome. In thoracic radiation myelopathies a dose difference between complete and incomplete transverse syndromes could be found as well. Incomplete transverse syndromes as submaximum radiation injuries are more suitable for the determination of the spinal tolerance dose than complete transverse syndromes. The lowest threshold could be stated for cases following high-volume irradiation of the lymphatic system. (Auth.)

  3. Experimentally studied dynamic dose interplay does not meaningfully affect target dose in VMAT SBRT lung treatments

    Energy Technology Data Exchange (ETDEWEB)

    Stambaugh, Cassandra [Department of Physics, University of South Florida, Tampa, Florida 33612 (United States); Nelms, Benjamin E. [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Dilling, Thomas; Stevens, Craig; Latifi, Kujtim; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States)

    2013-09-15

    Purpose: The effects of respiratory motion on the tumor dose can be divided into the gradient and interplay effects. While the interplay effect is likely to average out over a large number of fractions, it may play a role in hypofractionated [stereotactic body radiation therapy (SBRT)] treatments. This subject has been extensively studied for intensity modulated radiation therapy but less so for volumetric modulated arc therapy (VMAT), particularly in application to hypofractionated regimens. Also, no experimental study has provided full four-dimensional (4D) dose reconstruction in this scenario. The authors demonstrate how a recently described motion perturbation method, with full 4D dose reconstruction, is applied to describe the gradient and interplay effects during VMAT lung SBRT treatments.Methods: VMAT dose delivered to a moving target in a patient can be reconstructed by applying perturbations to the treatment planning system-calculated static 3D dose. Ten SBRT patients treated with 6 MV VMAT beams in five fractions were selected. The target motion (motion kernel) was approximated by 3D rigid body translation, with the tumor centroids defined on the ten phases of the 4DCT. The motion was assumed to be periodic, with the period T being an average from the empirical 4DCT respiratory trace. The real observed tumor motion (total displacement ≤8 mm) was evaluated first. Then, the motion range was artificially increased to 2 or 3 cm. Finally, T was increased to 60 s. While not realistic, making T comparable to the delivery time elucidates if the interplay effect can be observed. For a single fraction, the authors quantified the interplay effect as the maximum difference in the target dosimetric indices, most importantly the near-minimum dose (D{sub 99%}), between all possible starting phases. For the three- and five-fractions, statistical simulations were performed when substantial interplay was found.Results: For the motion amplitudes and periods obtained from

  4. Predicted allowable doses to normal organs for biologically targeted radiotherapy

    International Nuclear Information System (INIS)

    O'Donoghue, J.A.; Wheldon, T.E.; Western Regional Hospital Board, Glasgow

    1988-01-01

    The authors have used Dale's extension to the ''linear quadratic'' (LQ) model (Dale, 1985) to evaluate ''equivalent doses'' in cases involving exponentially decaying dose rates. This analysis indicates that the dose-rate effect will be a significant determinant of allowable doses to organs such as liver, kidney and lung. These organ tolerance doses constitute independent constraints on the therapeutic intensity of biologically targeted radiotherapy in exactly the same way as for conventional external beam radiotherapy. In the context of marrow rescue they will in all likelihood constitute the dose-limiting side-effects and thus be especially important. (author)

  5. Radiation research contracts: Biological effects of small radiation doses

    International Nuclear Information System (INIS)

    Hug, O.

    1959-01-01

    According to its Statute the IAEA has to fulfil a dual function - to help individual countries in solving their specific problems and to undertake tasks in the common interest of all its Member States. With this latter aim in mind the Agency has placed a number of research contracts with national research institutes. The purpose and scope of two of them is described below by the scientists responsible for their execution. The Agency has contributed to this work by putting at the institutes' disposal scientists from its own staff apparatus and financial aid.IAEA placed a research contract concerning the effects of small radiation doses on cells, in particular on nervous cells, with the Pharmacological Institute of the University of Vienna. This Institute appeared well suited to deal with the problem owing to the type of its previous research work. The Director, Prof. Franz Bruecke, and his collaborator Dr. Otto Kraupp, have long been interested in the functioning of the nervous system and in the influence of different drugs upon it. It was particularly fortunate that the electrical properties and functions of cells had been measured by a method specially developed at this Institute. From the above mentioned observations one could expect that instantaneous reactions of cells to radiation would also lead to changes of the electrical status. Consequently, this method is now being applied to the research undertaken for IAEA. Different cells of plants and animals, ranging from algae to muscle fibres of mammals, were chosen as objects. So far changes of potentials-had been observed only during irradiation with very high doses. During these investigations another useful test for small radiation doses was developed, namely the measurement of the through-flow of an artificial blood solution through the blood vessels of an intestinal loop. It was observed that a few seconds after irradiation the flow rate diminishes, and returns to its normal level only when irradiation ends

  6. Radiation research contracts: Biological effects of small radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Hug, O

    1959-01-15

    According to its Statute the IAEA has to fulfil a dual function - to help individual countries in solving their specific problems and to undertake tasks in the common interest of all its Member States. With this latter aim in mind the Agency has placed a number of research contracts with national research institutes. The purpose and scope of two of them is described below by the scientists responsible for their execution. The Agency has contributed to this work by putting at the institutes' disposal scientists from its own staff apparatus and financial aid.IAEA placed a research contract concerning the effects of small radiation doses on cells, in particular on nervous cells, with the Pharmacological Institute of the University of Vienna. This Institute appeared well suited to deal with the problem owing to the type of its previous research work. The Director, Prof. Franz Bruecke, and his collaborator Dr. Otto Kraupp, have long been interested in the functioning of the nervous system and in the influence of different drugs upon it. It was particularly fortunate that the electrical properties and functions of cells had been measured by a method specially developed at this Institute. From the above mentioned observations one could expect that instantaneous reactions of cells to radiation would also lead to changes of the electrical status. Consequently, this method is now being applied to the research undertaken for IAEA. Different cells of plants and animals, ranging from algae to muscle fibres of mammals, were chosen as objects. So far changes of potentials-had been observed only during irradiation with very high doses. During these investigations another useful test for small radiation doses was developed, namely the measurement of the through-flow of an artificial blood solution through the blood vessels of an intestinal loop. It was observed that a few seconds after irradiation the flow rate diminishes, and returns to its normal level only when irradiation ends

  7. Assessment of dose inhomogeneity at target level by in vivo dosimetry

    International Nuclear Information System (INIS)

    Leunens, G.; Verstraete, J.; Dutreix, A.; Schueren, E. van der

    1992-01-01

    Inhomogeneity of dose delivered to the target volume due to irregular body surface and tissue densities remains in many cases unknown, since dose distribution is calculated for most radiation treatments in only one transverse section and assuming the patient to be water equivalent. In this study transmission and target absorbed dose homogeneity is assessed for 11 head-and-neck cancer treatments by in vivo measurements with silicon diodes. Besides the dose to specification point, the dose delivered to 2-4 off-axis points in midline sagittal plane is estimated from entrance and exit dose measurements. Simultaneously made portal films allow to identify anatomical structures passed by the beam before reaching exit diode. Mean deviation from expected transmission is -6.8% for bone, +6% for air cavities and -2.5% for soft tissue. At midplane, mean deviations from expected target dose are respectively -3.5%, +2.3% and -1.9%. Deviations from prescribed dose are larger than 5% in 12/39 target points. Accuracy requirements in target dose delivery of plus or minus 5%, as proposed by ICRU, cannot be fulfilled in 7/11 patients and is mostly due to irregular body contour and tissue densities. as only a limited number of points are considered, inhomogeneity in dose delivered throughout whole irradiated volume is underestimated, as is illustrated from exit dose profiles obtained from portal image. Besides its tremendous value as a quality assurance procedure, in vivo dose measurements are shown to be a valid method for assessing dose delivered to irradiated tissues when dose computations are assumed to be inaccurate or even impossible in current practice. (author). 21 refs., 8 figs., 1 tab

  8. Risk of cancer subsequent to low-dose radiation

    International Nuclear Information System (INIS)

    Warren, S.

    1980-01-01

    The author puts low dose irradiation risks in perspective using average background radiation doses for standards. He assailed irresponsible media coverage during the height of public interest in the Three-Mile Island Reactor incident

  9. Radiation Dose-Volume Effects in the Brain

    International Nuclear Information System (INIS)

    Lawrence, Yaacov Richard; Li, X. Allen; El Naqa, Issam; Hahn, Carol A.; Marks, Lawrence B.; Merchant, Thomas E.; Dicker, Adam P.

    2010-01-01

    We have reviewed the published data regarding radiotherapy (RT)-induced brain injury. Radiation necrosis appears a median of 1-2 years after RT; however, cognitive decline develops over many years. The incidence and severity is dose and volume dependent and can also be increased by chemotherapy, age, diabetes, and spatial factors. For fractionated RT with a fraction size of 80 Gy. For large fraction sizes (≥2.5 Gy), the incidence and severity of toxicity is unpredictable. For single fraction radiosurgery, a clear correlation has been demonstrated between the target size and the risk of adverse events. Substantial variation among different centers' reported outcomes have prevented us from making toxicity-risk predictions. Cognitive dysfunction in children is largely seen for whole brain doses of ≥18 Gy. No substantial evidence has shown that RT induces irreversible cognitive decline in adults within 4 years of RT.

  10. Effects of low doses of ionizing radiation; Effets des faibles doses de rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Masse, R. [Office de Protection contre les Rayonnements Ionisants, 78 - le Vesinet (France)

    2006-07-01

    Several groups of human have been irradiated by accidental or medical exposure, if no gene defect has been associated to these exposures, some radioinduced cancers interesting several organs are observed among persons exposed over 100 to 200 mSv delivered at high dose rate. Numerous steps are now identified between the initial energy deposit in tissue and the aberrations of cell that lead to tumors but the sequence of events and the specific character of some of them are the subject of controversy. The stake of this controversy is the risk assessment. From the hypothesis called linear relationship without threshold is developed an approach that leads to predict cancers at any tiny dose without real scientific foundation. The nature and the intensity of biological effects depend on the quantity of energy absorbed in tissue and the modality of its distribution in space and time. The probability to reach a target (a gene) associated to the cancerating of tissue is directly proportional to the dose without any other threshold than the quantity of energy necessary to the effect, its probability of effect can be a more complex function and depends on the quality of the damage produced as well as the ability of the cell to repair the damage. These two parameters are influenced by the concentration of initial injuries in the target so by the quality of radiation and by the dose rate. The mechanisms of defence explain the low efficiency of radiation as carcinogen and then the linearity of effects in the area of low doses is certainly the least defensible scientific hypothesis for the prediction of the risks. (N.C.)

  11. Radiation effects after low dose chronic long-term exposure

    International Nuclear Information System (INIS)

    Fliedner, T.M.; Friesecke, I.

    1997-01-01

    This document approaches the radiation effects after low dose chronic long-term exposure, presenting examples occurred, the pathophysiologic mechanisms for cell system tolerance in elevated radiation fields, and the diagnostic and therapeutic possibilities

  12. Low dose radiation enhance the anti-tumor effect of high dose radiation on human glioma cell U251

    International Nuclear Information System (INIS)

    Wang Chang; Wang Guanjun; Tan Yehui; Jiang Hongyu; Li Wei

    2008-01-01

    Objective: To detect the effect on the growth of human glioma cell U251 induced by low dose irradiation and low dose irradiation combined with large dose irradiation. Methods: Human glioma cell line U251 and nude mice carried with human glioma were used. The tumor cells and the mice were treated with low dose, high dose, and low dose combined high dose radiation. Cells growth curve, MTT and flow cytometry were used to detect the proliferation, cell cycle and apoptosis of the cells; and the tumor inhibition rate was used to assess the growth of tumor in vivo. Results: After low dose irradiation, there was no difference between experimental group and control group in cell count, MTT and flow cytometry. Single high dose group and low dose combined high dose group both show significantly the suppressing effect on tumor cells, the apoptosis increased and there was cell cycle blocked in G 2 period, but there was no difference between two groups. In vivo apparent anti-tumor effect in high dose radiation group and the combining group was observed, and that was more significant in the combining group; the prior low dose radiation alleviated the injury of hematological system. There was no difference between single low dose radiation group and control. Conclusions: There is no significant effect on human glioma cell induced by low dose radiation, and low dose radiation could not induce adaptive response. But in vivo experience, low dose radiation could enhance the anti-tumor effect of high dose radiation and alleviated the injury of hematological system. (authors)

  13. Personal monitoring and assessment of doses received by radiation workers

    International Nuclear Information System (INIS)

    Swindon, T.N.; Morris, N.D.

    1981-12-01

    The Personal Radiation Monitoring Service operated by the Australian Radiation Laboratory is outlined and the types of monitors used for assessment of doses received by radiation workers are described. The distribution of doses received by radiation workers in different occupational categories is determined. From these distributions, the average doses received have been assessed and the maximum likely additional increase in cancer deaths in Australia as a result of occupational exposure estimated. This increase is shown to be very small. There is, however, a considerable spread of doses received by individuals within occupational groups

  14. Concept and computation of radiation dose at high energies

    International Nuclear Information System (INIS)

    Sarkar, P.K.

    2010-01-01

    Computational dosimetry, a subdiscipline of computational physics devoted to radiation metrology, is determination of absorbed dose and other dose related quantities by numbers. Computations are done separately both for external and internal dosimetry. The methodology used in external beam dosimetry is necessarily a combination of experimental radiation dosimetry and theoretical dose computation since it is not feasible to plan any physical dose measurements from inside a living human body

  15. Application of maximum values for radiation exposure and principles for the calculation of radiation doses

    International Nuclear Information System (INIS)

    2007-08-01

    The guide presents the definitions of equivalent dose and effective dose, the principles for calculating these doses, and instructions for applying their maximum values. The limits (Annual Limit on Intake and Derived Air Concentration) derived from dose limits are also presented for the purpose of monitoring exposure to internal radiation. The calculation of radiation doses caused to a patient from medical research and treatment involving exposure to ionizing radiation is beyond the scope of this ST Guide

  16. Target volume definition in radiation oncology

    CERN Document Server

    Grosu, Anca-Ligia

    2015-01-01

    The main objective of this book is to provide radiation oncologists with a clear, up-to-date guide to tumor delineation and contouring of organs at risk. With this in mind, a detailed overview of recent advances in imaging for radiation treatment planning is presented. Novel concepts for target volume delineation are explained, taking into account the innovations in imaging technology. Special attention is paid to the role of the newer imaging modalities, such as positron emission tomography and diffusion and perfusion magnetic resonance imaging. All of the most important tumor entities treate

  17. Cosmic radiation doses at flight level altitudes of airliners

    International Nuclear Information System (INIS)

    Viragh, E.; Petr, I.

    1985-01-01

    Changes are discussed in flux density of cosmic radiation particles with time as are the origin of cosmic radiation, the level of cosmic radiation near the Earth's surface, and the determination of cosmic radiation doses in airliners. Doses and dose rates are given measured on different flight routes. In spite of the fact that the flight duration at an altitude of about 10 km makes for about 80% of the total flight time, the overall radiation burden of the crews at 1000 flight hours a year is roughly double that of the rest of the population. (J.C.)

  18. Non-targeted effects of ionising radiation—Implications for low dose risk

    DEFF Research Database (Denmark)

    Kadhim, Munira; Salomaa, Sisko; Wright, Eric

    2013-01-01

    and adaptive responses are powered by fundamental, but not clearly understood systems that maintain tissue homeostasis. Despite excellent research in this field by various groups, there are still gaps in our understanding of the likely mechanisms associated with non-DNA targeted effects, particularly......Non-DNA targeted effects of ionising radiation, which include genomic instability, and a variety of bystander effects including abscopal effects and bystander mediated adaptive response, have raised concerns about the magnitude of low-dose radiation risk. Genomic instability, bystander effects....... Furthermore, it is still not known what the initial target and early interactions in cells are that give rise to non-targeted responses in neighbouring or descendant cells. This paper provides a commentary on the current state of the field as a result of the non-targeted effects of ionising radiation (NOTE...

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

    International Nuclear Information System (INIS)

    Sulieman, A.; Alzimami, K.; Habeeballa, B.; Osman, H.; Abdelaziz, I.; Sassi, S.A.; Sam, A.K.

    2015-01-01

    This study intends to measure the radiation dose to patients and staff during (i) Dynamic Hip Screw (DHS) and (ii) Dynamic Cannula Screw (DCS) and to evaluate entrance surface Air kerma (ESAK) dose and organ doses and effective doses. Calibrated Thermoluminescence dosimeters (TLD-GR200A) were used. The mean patients’ doses were 0.46 mGy and 0.07 mGy for DHS and DCS procedures, respectively. The mean staff doses at the thyroid and chest were 4.69 mGy and 1.21 mGy per procedure. The mean organ and effective dose for patients and staff were higher in DHS compared to DCS. Orthopedic surgeons were exposed to unnecessary radiation doses due to the lack of protection measures. The radiation dose per hip procedure is within the safety limit and less than the previous studies

  20. Effects of low dose radiation and epigenetic regulation

    International Nuclear Information System (INIS)

    Jiao Benzheng; Ma Shumei; Yi Heqing; Kong Dejuan; Zhao Guangtong; Gao Lin; Liu Xiaodong

    2010-01-01

    Purpose: To conclude the relationship between epigenetics regulation and radiation responses, especially in low-dose area. Methods: The literature was examined for papers related to the topics of DNA methylation, histone modifications, chromatin remodeling and non-coding RNA modulation in low-dose radiation responses. Results: DNA methylation and radiation can regulate reciprocally, especially in low-dose radiation responses. The relationship between histone methylation and radiation mainly exists in the high-dose radiation area; histone deacetylase (HDAC) inhibitors show a promising application to enhance radiation sensitivity, no matter whether in low-dose or high-dose areas; the connection between γ-H2AX and LDR has been remained unknown, although γ-H2AX has been shown no radiation sensitivities with 1-15 Gy irradiation; histone ubiquitination play an important role in DNA damage repair mechanism. Moreover, chromatin remodeling has an integral role in DSB repair and the chromatin response, in general, may be precede DNA end resection. Finally, the effect of radiation on miRNA expression seems to vary according to cell type, radiation dose, and post-irradiation time point. Conclusion: Although the advance of epigenetic regulation on radiation responses, which we are managing to elucidate in this review, has been concluded, there are many questions and blind blots deserved to investigated, especially in low-dose radiation area. However, as progress on epigenetics, we believe that many new elements will be identified in the low-dose radiation responses which may put new sights into the mechanisms of radiation responses and radiotherapy. (authors)

  1. SU-F-J-133: Adaptive Radiation Therapy with a Four-Dimensional Dose Calculation Algorithm That Optimizes Dose Distribution Considering Breathing Motion

    Energy Technology Data Exchange (ETDEWEB)

    Ali, I; Algan, O; Ahmad, S [University of Oklahoma Health Sciences, Oklahoma City, OK (United States); Alsbou, N [University of Central Oklahoma, Edmond, OK (United States)

    2016-06-15

    Purpose: To model patient motion and produce four-dimensional (4D) optimized dose distributions that consider motion-artifacts in the dose calculation during the treatment planning process. Methods: An algorithm for dose calculation is developed where patient motion is considered in dose calculation at the stage of the treatment planning. First, optimal dose distributions are calculated for the stationary target volume where the dose distributions are optimized considering intensity-modulated radiation therapy (IMRT). Second, a convolution-kernel is produced from the best-fitting curve which matches the motion trajectory of the patient. Third, the motion kernel is deconvolved with the initial dose distribution optimized for the stationary target to produce a dose distribution that is optimized in four-dimensions. This algorithm is tested with measured doses using a mobile phantom that moves with controlled motion patterns. Results: A motion-optimized dose distribution is obtained from the initial dose distribution of the stationary target by deconvolution with the motion-kernel of the mobile target. This motion-optimized dose distribution is equivalent to that optimized for the stationary target using IMRT. The motion-optimized and measured dose distributions are tested with the gamma index with a passing rate of >95% considering 3% dose-difference and 3mm distance-to-agreement. If the dose delivery per beam takes place over several respiratory cycles, then the spread-out of the dose distributions is only dependent on the motion amplitude and not affected by motion frequency and phase. This algorithm is limited to motion amplitudes that are smaller than the length of the target along the direction of motion. Conclusion: An algorithm is developed to optimize dose in 4D. Besides IMRT that provides optimal dose coverage for a stationary target, it extends dose optimization to 4D considering target motion. This algorithm provides alternative to motion management

  2. Analysis of occupational doses of radiation workers in medical institutions

    International Nuclear Information System (INIS)

    Sanaye, S.S.; Baburajan, Sujatha; Joshi, V.D.; Pawar, S.G.; Nalawade, S.K.; Raman, N.V.; Kher, R.K.

    2007-01-01

    Routine monitoring of occupational radiation workers is done for controlling the doses to the individuals and to demonstrate the compliance with occupational dose limits. One of the objective of personnel monitoring program is the assessment of the radiation safety of working area and trends of exposure histories of individuals or group of workers. Computerised dose registry of all monitored radiation workers along with their personnel data helps in analyzing these trends. This in turn helps the institutions in management of their radiation safety programs. In India, annual and life time occupational dose records are maintained as National Dose Registry in the Radiological Physics and Advisory Division, Bhabha Atomic Research Centre. This paper presents analysis of occupational dose data of monitored radiation workers in medical institutions in India during last five years (i.e. 2002-2006)

  3. Effect of low dose radiation on apoptosis in mouse spleen

    International Nuclear Information System (INIS)

    Chen Dong; Liu Jiamei; Chen Aijun; Liu Shuzheng

    1999-01-01

    Objective: To study the effect of whole body irradiation (WBI) with different doses of X-ray on apoptosis in mouse spleen. Methods: Time course changes and dose-effect relationship of apoptosis in mouse spleen induced by WBI were observed with transmission electron microscopy (TEM) qualitatively and TUNEL method semi-quantitatively. Results: Many typical apoptotic lymphocytes were found by TEM in mouse spleen after WBI with 2 Gy. No marked alterations of ultrastructure were found following WBI with 0.075 Gy. It was observed by TUNEL that the apoptosis of splenocytes increased after high dose radiation and decreased following low dose radiation (LDR). The dose-effect relationship of radiation-induced apoptosis showed a J-shaped curve. Conclusion: The effect of different doses of ionizing radiation on apoptosis in mouse spleen was distinct. And the decrease of apoptosis after LDR is considered a manifestation of radiation hormesis

  4. MONTEC, an interactive fortran program to simulate radiation dose and dose-rate responses of populations

    International Nuclear Information System (INIS)

    Perry, K.A.; Szekely, J.G.

    1983-09-01

    The computer program MONTEC was written to simulate the distribution of responses in a population whose members are exposed to multiple radiation doses at variable dose rates. These doses and dose rates are randomly selected from lognormal distributions. The individual radiation responses are calculated from three equations, which include dose and dose-rate terms. Other response-dose/rate relationships or distributions can be incorporated by the user as the need arises. The purpose of this documentation is to provide a complete operating manual for the program. This version is written in FORTRAN-10 for the DEC system PDP-10

  5. Dose Recalculation and the Dose-Guided Radiation Therapy (DGRT) Process Using Megavoltage Cone-Beam CT

    International Nuclear Information System (INIS)

    Cheung, Joey; Aubry, Jean-Francois; Yom, Sue S.; Gottschalk, Alexander R.; Celi, Juan Carlos; Pouliot, Jean

    2009-01-01

    Purpose: At University of California San Francisco, daily or weekly three-dimensional images of patients in treatment position are acquired for image-guided radiation therapy. These images can be used for calculating the actual dose delivered to the patient during treatment. In this article, we present the process of performing dose recalculation on megavoltage cone-beam computed tomography images and discuss possible strategies for dose-guided radiation therapy (DGRT). Materials and Methods: A dedicated workstation has been developed to incorporate the necessary elements of DGRT. Patient image correction (cupping, missing data artifacts), calibration, completion, recontouring, and dose recalculation are all implemented in the workstation. Tools for dose comparison are also included. Examples of image correction and dose analysis using 6 head-and-neck and 2 prostate patient datasets are presented to show possible tracking of interfraction dosimetric endpoint variation over the course of treatment. Results: Analysis of the head-and-neck datasets shows that interfraction treatment doses vary compared with the planning dose for the organs at risk, with the mean parotid dose and spinal cord D 1 increasing by as much as 52% and 10%, respectively. Variation of the coverage to the target volumes was small, with an average D 5 dose difference of 1%. The prostate patient datasets revealed accurate dose coverage to the targeted prostate and varying interfraction dose distributions to the organs at risk. Conclusions: An effective workflow for the clinical implementation of DGRT has been established. With these techniques in place, future clinical developments in adaptive radiation therapy through daily or weekly dosimetric measurements of treatment day images are possible.

  6. Non-Targeted effects of ionising radiation and radiotherapy

    International Nuclear Information System (INIS)

    Sjostedt, Svetlana; Bezak, Eva

    2010-01-01

    Full text: Modern radiobiology is undergoing rapid change due to new discoveries contradicting the target concept which is currently used to predict dose-response relationships. Thus relatively recently discovered radiation induced bystander effects (RlBEs), that include additional death, mutation and radio-adaptation in non-irradiated cells, change our understanding of the target concept and broadens its boundaries. This can be significant from a radioprotection point of view and also has the potential to reassess radiation damage models currently used in radiotherapy. This article reviews briefly the general concepts of RlBEs such as the proposed underlying mechanisms of signal induction and propagation, experimental approaches and biological end points used to investigate these phenomena. It also summ rises several mathematical models currently proposed in an attempt to quantify RlBE. The main emphasis of this al1icle is to review and highlight the potential impact of the bystander phenomena in radiotherapy.

  7. Follow up on a workloaded interventional radiologist's occupational radiation doses - a study case

    International Nuclear Information System (INIS)

    Ketner, D.; Ofer, A.; Engel, A.

    2004-01-01

    During many interventional procedures, patients' radiation doses are high, affecting radiologist's radiation doses. We checked occupational doses of a workloaded interventional radiologist during seven years

  8. Knowledge of medical imaging radiation dose and risk among doctors

    International Nuclear Information System (INIS)

    Brown, Nicholas; Jones, Lee

    2013-01-01

    The growth of computed tomography (CT) and nuclear medicine (NM) scans has revolutionised healthcare but also greatly increased population radiation doses. Overuse of diagnostic radiation is becoming a feature of medical practice, leading to possible unnecessary radiation exposures and lifetime-risks of developing cancer. Doctors across all medical specialties and experience levels were surveyed to determine their knowledge of radiation doses and potential risks associated with some diagnostic imaging. A survey relating to knowledge and understanding of medical imaging radiation was distributed to doctors at 14 major Queensland public hospitals, as well as fellows and trainees in radiology, emergency medicine and general practice. From 608 valid responses, only 17.3% correctly estimated the radiation dose from CT scans and almost 1 in 10 incorrectly believed that CT radiation is not associated with any increased lifetime risk of developing cancer. There is a strong inverse relationship between a clinician's experience and their knowledge of CT radiation dose and risks, even among radiologists. More than a third (35.7%) of doctors incorrectly believed that typical NM imaging either does not use ionising radiation or emits doses equal to or less than a standard chest radiograph. Knowledge of CT and NM radiation doses is poor across all specialties, and there is a significant inverse relationship between experience and awareness of CT dose and risk. Despite having a poor understanding of these concepts, most doctors claim to consider them prior to requesting scans and when discussing potential risks with patients.

  9. Is uniform target dose possible in IMRT plans in the head and neck?

    International Nuclear Information System (INIS)

    Vineberg, K.A.; Eisbruch, A.; Coselmon, M.M.; McShan, D.L.; Kessler, M.L.; Fraass, B.A.

    2002-01-01

    was shown that relatively few patients would benefit from the use of increased target inhomogeneity, because the range of improvement in the parotid dose is relatively limited. Hot spots in the target volumes are shown to be unnecessary and do not assist in normal tissue sparing. Conclusion: Sparing of both parotids in patients receiving bilateral neck radiation can be achieved without compromising strict target dose homogeneity criteria. The geometry of the normal tissue and target anatomy are shown to be the major factor necessary to predict the parotid sparing that will be possible for any particular case

  10. Electronic radiative capture in solid targets

    International Nuclear Information System (INIS)

    Pregliasco, R.; Nemirovsky, I.; Suarez, S.

    1988-01-01

    X-ray spectra originating from electron radiative capture from aluminium target to K shell on F 9+ and F 8+ beams with 115MeV are studied. Using an electrostatic analyzer, it was obtained the charge fractions Fi to aluminiun thicknesses of 39 and 58 micrograms/cm 2 . These thicknesses are determined by the stopping power of alpha particles. (A.C.A.S.) [pt

  11. Radiation dose to the patient in radionuclide studies

    International Nuclear Information System (INIS)

    Roedler, H.D.

    1981-01-01

    In medical radionuclide studies, the radiation risk has to be considered in addition to the general risk of administering a pharmaceutical. As radiation exposure is an essential factor in radiation risk estimation, some aspects of internal dose calculation, including radiation risk assessments, are treated. The formalism of current internal dose calculation is presented. The input data, especially the residence time and the absorbed dose per transformation, their origin and accuracy are discussed. Results of internal dose calculations for the ten most frequently used radionuclide studies are presented as somatically effective dose equivalents. The accuracy of internal dose calculation is treated in detail by considering the biokinetics of the radiopharmaceutical, the phantoms used for dose calculations, the absorbed dose per transformation, the administered activity, and the transfer of the dose, calculated for a phantom, to the patient. The internal dose calculated for a reference phantom may be assumed to be in accordance with the actual patient dose within a range described by a factor of about two to three. Finally, risk estimates for nuclear medicine procedures are quantified, being generally of sixth order. The radiation risk from the radioiodine test is comparably higher, but probably lower than calculated according to the UNSCEAR risk coefficients. However, further studies are needed to confirm these preliminary results and to improve the quantification of the radiation risk from the medical use of radionuclides. (author)

  12. Theoretic simulation for CMOS device on total dose radiation response

    International Nuclear Information System (INIS)

    He Baoping; Zhou Heqin; Guo Hongxia; He Chaohui; Zhou Hui; Luo Yinhong; Zhang Fengqi

    2006-01-01

    Total dose effect is simulated for C4007B, CC4007RH and CC4011 devices at different absorbed dose rate by using linear system theory. When irradiation response and dose are linear, total dose radiation and post-irradiation annealing at room temperature are determined for one random by choosing absorbed dose rate, and total dose effect at other absorbed dose rate can be predicted by using linear system theory. The simulating results agree with the experimental results at different absorbed dose rate. (authors)

  13. A study of different dose calculation methods and the impact on the dose evaluation protocol in lung stereotactic radiation therapy

    International Nuclear Information System (INIS)

    Takada, Takahiro; Furuya, Tomohisa; Ozawa, Shuichi; Ito, Kana; Kurokawa, Chie; Karasawa, Kumiko; Miura, Kohei

    2008-01-01

    AAA (analytical anisotropic algorithm) dose calculation, which shows a better performance for heterogeneity correction, was tested for lung stereotactic radiation therapy (SBRT) in comparison to conventional PBC (pencil beam convolution method) to evaluate its impact on tumor dose parameters. Eleven lung SBRT patients who were treated with photon 4 MV beams in our department between April 2003 and February 2007 were reviewed. Clinical target volume (CTV) was delineated including the spicula region on planning CT images. Planning target volume (PTV) was defined by adding the internal target volume (ITV) and set-up margin (SM) of 5 mm from CTV, and then an multileaf collimator (MLC) penumbra margin of another 5 mm was also added. Six-port non-coplanar beams were employed, and a total prescribed dose of 48 Gy was defined at the isocenter point with four fractions. The entire treatment for an individual patient was completed within 8 days. Under the same prescribed dose, calculated dose distribution, dose volume histogram (DVH), and tumor dose parameters were compared between two dose calculation methods. In addition, the fractionated prescription dose was repeatedly scaled until the monitor units (MUs) calculated by AAA reached a level of MUs nearly identical to those achieved by PBC. AAA resulted in significantly less D95 (irradiation dose that included 95% volume of PTV) and minimal dose in PTV compared to PBC. After rescaling of each MU for each beam in the AAA plan, there was no revision of the isocenter of the prescribed dose required. However, when the PTV volume was less than 20 cc, a 4% lower prescription resulted in nearly identical MUs between AAA and PBC. The prescribed dose in AAA should be the same as that in PBC, if the dose is administered at the isocenter point. However, planners should compare DVHs and dose distributions between AAA and PBC for a small lung tumor with a PTV volume less than approximately 20 cc. (author)

  14. MOSFET assessment of radiation dose delivered to mice using the Small Animal Radiation Research Platform (SARRP).

    Science.gov (United States)

    Ngwa, Wilfred; Korideck, Houari; Chin, Lee M; Makrigiorgos, G Mike; Berbeco, Ross I

    2011-12-01

    The Small Animal Radiation Research Platform (SARRP) is a novel isocentric irradiation system that enables state-of-the-art image-guided radiotherapy research to be performed with animal models. This paper reports the results obtained from investigations assessing the radiation dose delivered by the SARRP to different anatomical target volumes in mice. Surgically implanted metal oxide semiconductor field effect transistors (MOSFET) dosimeters were employed for the dose assessment. The results reveal differences between the calculated and measured dose of -3.5 to 0.5%, -5.2 to -0.7%, -3.9 to 0.5%, -5.9 to 2.5%, -5.5 to 0.5%, and -4.3 to 0% for the left kidney, liver, pancreas, prostate, left lung, and brain, respectively. Overall, the findings show less than 6% difference between the delivered and calculated dose, without tissue heterogeneity corrections. These results provide a useful assessment of the need for tissue heterogeneity corrections in SARRP dose calculations for clinically relevant tumor model sites.

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

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

  16. Monte Carlo simulation on hard X-ray dose produced in interaction between high intensity laser and solid target

    International Nuclear Information System (INIS)

    Yang Bo; Qiu Rui; Li Junli; Zhang Hui

    2014-01-01

    The X-ray dose produced in the interaction between high intensity laser and solid target was studied by simulation using Monte Carlo code. Compared with experimental results, the calculation model was verified. The calculation model was used to study the effect on X-ray dose with different electron temperatures, target materials (including Au, Cu and PE) and thicknesses. The results indicate that the X-ray dose is mainly determined by the electron temperature, and will be affected by the target parameters. X-ray dose of Au is about 1.2 times that of Cu, and is about 5 times that of PE (polyethylene). In addition, compared with other target thickness, when target thickness is the mean range of electron in the target, X-ray dose is relatively large. These results will provide references on evaluating the ionizing radiation dose for laser devices. (authors)

  17. CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

    Science.gov (United States)

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

  18. Study of genomic instability induced by low dose ionizing radiation

    International Nuclear Information System (INIS)

    Seoane, A.; Crudeli, C.; Dulout, F.

    2006-01-01

    The crews of commercial flights and services staff of radiology and radiotherapy from hospitals are exposed to low doses of ionizing radiation. Genomic instability includes those adverse effects observed in cells, several generations after the exposure occurred. The purpose of this study was to analyze the occurrence of genomic instability by very low doses of ionizing radiation [es

  19. Measuring radiation dose to patients undergoing fluoroscopically-guided interventions

    International Nuclear Information System (INIS)

    Lubis, L E; Badawy, M K

    2016-01-01

    The increasing prevalence and complexity of fluoroscopically guided interventions (FGI) raises concern regarding radiation dose to patients subjected to the procedure. Despite current evidence showing the risk to patients from the deterministic effects of radiation (e.g. skin burns), radiation induced injuries remain commonplace. This review aims to increase the awareness surrounding radiation dose measurement for patients undergoing FGI. A review of the literature was conducted alongside previous researches from the authors’ department. Studies pertaining to patient dose measurement, its formalism along with current advances and present challenges were reviewed. Current patient monitoring techniques (using available radiation dosimeters), as well as the inadequacy of accepting displayed dose as patient radiation dose is discussed. Furthermore, advances in real-time patient radiation dose estimation during FGI are considered. Patient dosimetry in FGI, particularly in real time, remains an ongoing challenge. The increasing occurrence and sophistication of these procedures calls for further advances in the field of patient radiation dose monitoring. Improved measuring techniques will aid clinicians in better predicting and managing radiation induced injury following FGI, thus improving patient care. (paper)

  20. Spine stereotactic body radiation therapy plans: Achieving dose coverage, conformity, and dose falloff

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Linda X., E-mail: lhong0812@gmail.com [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States); Shankar, Viswanathan [Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY (United States); Shen, Jin [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Kuo, Hsiang-Chi [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States); Mynampati, Dinesh [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Yaparpalvi, Ravindra [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States); Goddard, Lee [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Basavatia, Amar; Fox, Jana; Garg, Madhur; Kalnicki, Shalom; Tomé, Wolfgang A. [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States)

    2015-10-01

    We report our experience of establishing planning objectives to achieve dose coverage, conformity, and dose falloff for spine stereotactic body radiation therapy (SBRT) plans. Patients with spine lesions were treated using SBRT in our institution since September 2009. Since September 2011, we established the following planning objectives for our SBRT spine plans in addition to the cord dose constraints: (1) dose coverage—prescription dose (PD) to cover at least 95% planning target volume (PTV) and 90% PD to cover at least 99% PTV; (2) conformity index (CI)—ratio of prescription isodose volume (PIV) to the PTV < 1.2; (3) dose falloff—ratio of 50% PIV to the PTV (R{sub 50%}); (4) and maximum dose in percentage of PD at 2 cm from PTV in any direction (D{sub 2cm}) to follow Radiation Therapy Oncology Group (RTOG) 0915. We have retrospectively reviewed 66 separate spine lesions treated between September 2009 and December 2012 (31 treated before September 2011 [group 1] and 35 treated after [group 2]). The χ{sup 2} test was used to examine the difference in parameters between groups. The PTV V{sub 100%} {sub PD} ≥ 95% objective was met in 29.0% of group 1 vs 91.4% of group 2 (p < 0.01) plans. The PTV V{sub 90%} {sub PD} ≥ 99% objective was met in 38.7% of group 1 vs 88.6% of group 2 (p < 0.01) plans. Overall, 4 plans in group 1 had CI > 1.2 vs none in group 2 (p = 0.04). For D{sub 2cm}, 48.3% plans yielded a minor violation of the objectives and 16.1% a major violation for group 1, whereas 17.1% exhibited a minor violation and 2.9% a major violation for group 2 (p < 0.01). Spine SBRT plans can be improved on dose coverage, conformity, and dose falloff employing a combination of RTOG spine and lung SBRT protocol planning objectives.

  1. The limiting dose rate and its importance in radiation protection

    International Nuclear Information System (INIS)

    Bakkiam, D.; Sonwani, Swetha; Arul Ananthakumar, A.; Mohankumar, Mary N.

    2012-01-01

    The concept of defining a low dose of ionizing radiation still remains unclear. Before attempting to define a low dose, it is more important to define a low-dose rate since effects at low dose-rates are different from those observed at higher dose-rates. Hence, it follows that low dose-rates rather than a low dose is an important criteria to determine radio-biological effects and risk factors i.e. stochastic health effects. Chromosomal aberrations induced by ionizing radiations are well fitted by quadratic model Y= áD + âD 2 + C with the linear coefficient of dose predominating for high LET radiations and low doses of low LET. At higher doses and dose rates of sparsely ionizing radiation, break pairs produced by inter-track action leads to the formation of exchange type aberrations and is dependent on dose rate. Whereas at lower doses and dose rates, intra-track action produces break pairs and resulting aberrations are in direct proportion to absorbed dose and independent of dose rate. The dose rate at which inter-track ceases to be observable and where intra-track action effectively becomes the sole contributor of lesion-pair formation is referred to as limiting dose rate (LDR). Once the LDR is reached further reduction in dose rates will not affect the slope of DR since breaks produced by independent charged particle tracks are widely separated in time to interact with each other for aberration yield. This linear dependency is also noticed for acute exposures at very low doses. Existing reports emphasizes the existence of LDR likely to be e6.3cGyh -1 . However no systematic studies have been conducted so far to determine LDR. In the present investigation DR curves were constructed for the dose rates 0.002 and 0.003 Gy/min and to define LDR at which a coefficient approaches zero. Extrapolation of limiting low dose rate data can be used to predict low dose effects regardless of dose rate and its definition ought to serve as a useful index for studies pertaining

  2. Intensity Modulated Radiation Therapy With Dose Painting to Treat Rhabdomyosarcoma

    International Nuclear Information System (INIS)

    Yang, Joanna C.; Dharmarajan, Kavita V.; Wexler, Leonard H.; La Quaglia, Michael P.; Happersett, Laura; Wolden, Suzanne L.

    2012-01-01

    Purpose: To examine local control and patterns of failure in rhabdomyosarcoma patients treated with intensity modulated radiation therapy (RT) with dose painting (DP-IMRT). Patients and Methods: A total of 41 patients underwent DP-IMRT with chemotherapy for definitive treatment. Nineteen also underwent surgery with or without intraoperative RT. Fifty-six percent had alveolar histologic features. The median interval from beginning chemotherapy to RT was 17 weeks (range, 4-25). Very young children who underwent second-look procedures with or without intraoperative RT received reduced doses of 24-36 Gy in 1.4-1.8-Gy fractions. Young adults received 50.4 Gy to the primary tumor and lower doses of 36 Gy in 1.8-Gy fractions to at-risk lymph node chains. Results: With 22 months of median follow-up, the actuarial local control rate was 90%. Patients aged ≤7 years who received reduced overall and fractional doses had 100% local control, and young adults had 79% (P=.07) local control. Three local failures were identified in young adults whose primary target volumes had received 50.4 Gy in 1.8-Gy fractions. Conclusions: DP-IMRT with lower fractional and cumulative doses is feasible for very young children after second-look procedures with or without intraoperative RT. DP-IMRT is also feasible in adolescents and young adults with aggressive disease who would benefit from prophylactic RT to high-risk lymph node chains, although dose escalation might be warranted for improved local control. With limited follow-up, it appears that DP-IMRT produces local control rates comparable to those of sequential IMRT in patients with rhabdomyosarcoma.

  3. Radiation dose distributions due to sudden ejection of cobalt device.

    Science.gov (United States)

    Abdelhady, Amr

    2016-09-01

    The evaluation of the radiation dose during accident in a nuclear reactor is of great concern from the viewpoint of safety. One of important accident must be analyzed and may be occurred in open pool type reactor is the rejection of cobalt device. The study is evaluating the dose rate levels resulting from upset withdrawal of co device especially the radiation dose received by the operator in the control room. Study of indirect radiation exposure to the environment due to skyshine effect is also taken into consideration in order to evaluate the radiation dose levels around the reactor during the ejection trip. Microshield, SHLDUTIL, and MCSky codes were used in this study to calculate the radiation dose profiles during cobalt device ejection trip inside and outside the reactor building. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Calculation of the dose caused by internal radiation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    For the purposes of monitoring radiation exposure it is necessary to determine or to estimate the dose caused by both external and internal radiation. When comparing the value of exposure to the dose limits, account must be taken of the total dose incurred from different sources. This guide explains how to calculate the committed effective dose caused by internal radiation and gives the conversion factors required for the calculation. Application of the maximum values for radiation exposure is dealt with in ST guide 7.2, which also sets out the definitions of the quantities and concepts most commonly used in the monitoring of radiation exposure. The monitoring of exposure and recording of doses are dealt with in ST Guides 7.1 and 7.4.

  5. Low dose radiation and plant growth

    International Nuclear Information System (INIS)

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

    2001-03-01

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

  6. Low dose radiation and plant growth

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-03-01

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

  7. Evaluation of Patient Radiation Dose during Orthopedic Surgery

    International Nuclear Information System (INIS)

    Osman, H; Elzaki, A.; Sam, A.K.; Sulieman, A.

    2013-01-01

    The number of orthopedic procedures requiring the use of the fluoroscopic guidance has increased over the recent years. Consequently the patient exposed to un avoidable radiation doses. The aim of the current study was to evaluate patient radiation dose during these procedures.37 patients under went dynamic hip screw (DHS) and dynamic cannulated screw (DCS) were evaluated using calibrated Thermolumincent Dosimeters (TLDs), under carm fluoroscopic machines ,in three centers in Khartoum-Sudan. The mean Entrance Skin Dose (ESD) was 7.9 m Gy per procedure. The bone marrow and gonad organ exposed to significant doses. No correlation was found between ESD and Body Mass Index (BMI), or patient weight. Well correlation was found between kilo voltage applied and ESD. Orthopedic surgeries delivered lower radiation dose to patients than cardiac catheterization or hysterosalpingraphy (HSG) procedures. More study should be implemented to follow radiation dose before surgery and after surgery

  8. Biological influence from low dose and low-dose rate radiation

    International Nuclear Information System (INIS)

    Magae, Junji

    2007-01-01

    Although living organisms have defense mechanisms for radioadaptive response, the influence is considered to vary qualitatively and quantitatively for low dose and high dose, as well as for low-dose rate and high-dose rate. This article describes the bioresponse to low dose and low-dose rate. Among various biomolecules, DNA is the most sensitive to radiation, and accurate replication of DNA is an essential requirement for the survival of living organisms. Also, the influence of active enzymes resulted from the effect of radiation on enzymes in the body is larger than the direct influence of radiation on the body. After this, the article describes the carcinogenic risk by low-dose radiation, and then so-called Hormesis effect to create cancer inhibition effect by stimulating active physiology. (S.K.)

  9. Radiation dose of CT coronary angiography in clinical practice: Objective evaluation of strategies for dose optimization

    International Nuclear Information System (INIS)

    Yerramasu, Ajay; Venuraju, Shreenidhi; Atwal, Satvir; Goodman, Dennis; Lipkin, David; Lahiri, Avijit

    2012-01-01

    Background: CT coronary angiography (CTCA) is an evolving modality for the diagnosis of coronary artery disease. Radiation burden associated with CTCA has been a major concern in the wider application of this technique. It is important to reduce the radiation dose without compromising the image quality. Objectives: To estimate the radiation dose of CTCA in clinical practice and evaluate the effect of dose-saving algorithms on radiation dose and image quality. Methods: Effective radiation dose was measured from the dose-length product in 616 consecutive patients (mean age 58 ± 12 years; 70% males) who underwent clinically indicated CTCA at our institution over 1 year. Image quality was assessed subjectively using a 4-point scale and objectively by measuring the signal- and contrast-to-noise ratios in the coronary arteries. Multivariate linear regression analysis was used to identify factors independently associated with radiation dose. Results: Mean effective radiation dose of CTCA was 6.6 ± 3.3 mSv. Radiation dose was significantly reduced by dose saving algorithms such as 100 kV imaging (−47%; 95% CI, −44% to −50%), prospective gating (−35%; 95% CI, −29% to −40%) and ECG controlled tube current modulation (−23%; 95% CI, −9% to −34%). None of the dose saving algorithms were associated with a significant reduction in mean image quality or the frequency of diagnostic scans (P = non-significant for all comparisons). Conclusion: Careful application of radiation-dose saving algorithms in appropriately selected patients can reduce the radiation burden of CTCA significantly, without compromising the image quality.

  10. Occupational radiation dose in Indonesia 1981-1986

    International Nuclear Information System (INIS)

    Hiswara, E.; Ismono, A.

    1993-01-01

    Occupational radiation dose in Indonesia 1981-1986. This paper presents the occupational radiation dose in Indonesia during the period of 1981-1986. The highest collective dose accurated in 1983 was calculated to be 2.68 man-Sv, with the maximum mean dose per worker, who received dose more than zero, was around 11.07 mSv in the same year. In 1985, a relative collective dose from medical occupations of 1.88 man mSv for 10 6 population was estimated based on its total collective dose of 0.31 man-mSv. The total number of workers who received annual collective dose less than 5 mSv varied from 97.0% in 1981 to 99.5% in 1986. As a group, the industrial occupations has considerably higher risk in receiving a dose than others. (authors). 11 refs., 7 tabs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-12-31

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

  12. Radiation Dose Risk and Diagnostic Benefit in Imaging Investigations

    OpenAIRE

    Dobrescu, Lidia; Rădulescu, Gheorghe-Cristian

    2015-01-01

    The paper presents many facets of medical imaging investigations radiological risks. The total volume of prescribed medical investigations proves a serious lack in monitoring and tracking of the cumulative radiation doses in many health services. Modern radiological investigations equipment is continuously reducing the total dose of radiation due to improved technologies, so a decrease in per caput dose can be noticed, but the increasing number of investigations has determined a net increase ...

  13. 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

  14. 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

  15. Patient radiation dose in conventional and xerographic cephalography

    International Nuclear Information System (INIS)

    Copley, R.L.; Glaze, S.A.; Bushong, S.C.; West, D.C.

    1979-01-01

    A comparison of the radiation doses for xeroradiographic and conventional film screen cephalography was made. Alderson tissue-equivalent phantoms were used for patient simulation. An optimum technique in terms of patient dose and image quality indicated that the dose for the Xerox process ranged from five to eleven times greater than that for the conventional process for entrance and exit exposures, respectively. This dose, however, falls within an acceptable range for other dental and medical radiation doses. It is recommended that conventional cephalography be used for routine purposes and that xeroradiography be reserved for situations requiring the increased image quality that the process affords

  16. Dose enhancement effects of X ray radiation in bipolar transistors

    International Nuclear Information System (INIS)

    Chen Panxun

    1997-01-01

    The author has presented behaviour degradation and dose enhancement effects of bipolar transistors in X ray irradiation environment. The relative dose enhancement factors of X ray radiation were measured in bipolar transistors by the experiment methods. The mechanism of bipolar device dose enhancement was investigated

  17. Natural radiation dose to Gammarus from Hudson river

    International Nuclear Information System (INIS)

    Paschoa, A.S.; Wrenn, M.E.; Eisenbud, M.

    1979-01-01

    The purpose of this investigation is to evaluate the natural radiation dose rate to whole body and components of the Gammarus species, a zooplankton which occurs in the Hudson River among other places, and to compare the results with the upper limits of dose rates from man-made sources. The alpha dose rates to the exoskeleton and soft tissues are about 10 times the average alpha dose rate to the whole body, assuming uniform distribution of 226 Ra. The natural alpha radiation dose rate to Gammarus represents only about 5% of the total natural dose to the organism, i.e., 492 mrad/yr. The external dose rate due to 40 K, 238 U plus daughters and 232 Th plus daughters accumulated in the sediments comprise 91% of that total natural dose rate, the remaining percentage being due to natural internal beta emitters and cosmic radiation. Man-made sources can cause an external dose rate up to 224 mrad/yr, which comprises roughly 1/3 of the total dose rate (up to 716 mrad/yr; natural plus man-made) to the Gammarus of Hudson River in front of Indian Point Nuclear Power Station. However, in terms of dose-equivalent the natural sources of radiation would contribute more than 75% of the total dose to Gammarus

  18. The dose limits in radiation protection: foundations and evolution perspectives

    International Nuclear Information System (INIS)

    Lochard, J.

    1999-01-01

    The first part of this article is devoted to the evolution of dose limits in radiation protection since 1928. The second part tackles the difficulties to whom the ICRP system of limitation collides with. The notions of dose limits, ALARA principle are explained and the concept of dose constraints is introduced. (N.C.)

  19. Radiation doses in pediatric radiology: influence of regulations and standards

    International Nuclear Information System (INIS)

    Suleiman, O.H.

    2004-01-01

    The benefits of X-ray examinations contribute to the quality of modern medicine; however the risk of using X-rays, a carcinogen, has always been a concern. This concern is heightened for pediatric patients, who have a much greater sensitivity to the carcinogenic effects of radiation than adults. The principle of as low as reasonably achievable, or ALARA, is essential for minimizing the radiation dose patients receive, especially for pediatric patients. In order to keep radiation doses ALARA, one must know the dose patients receive. The determination of radiation dose in a standard way is therefore necessary so that these doses can be compared with practice, and for meaningful comparison against voluntary standards. In extreme situations, where public health needs may require mandatory standards, or regulations, the quantitative measurement and calculation of radiation dose becomes essential. How some radiation dose metrics and standards have evolved, including the value of different metrics such as entrance air kerma, organ dose, and effective dose will be presented. Recent pediatric X-ray studies, whether or not dedicated pediatric equipment is necessary, and recent initiatives by the Food and Drug Administration for pediatric population will be discussed. (orig.)

  20. 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)

  1. Assessment of dose level of ionizing radiation in army scrap

    International Nuclear Information System (INIS)

    Abdel Hamid, S. M.

    2010-12-01

    Radiation protection is the science of protecting people and the environment from the harmful effects of ionizing radiation, which includes both particle radiation and high energy radiation. Ionizing radiation is widely used in industry and medicine. Any human activity of nuclear technologies should be linked to the foundation of scientific methodology and baseline radiation culture to avoid risk of radiation and should be working with radioactive materials and expertise to understand, control practices in order to avoid risks that could cause harm to human and environment. The study was conducted in warehouses and building of Sudan air force Khartoum basic air force during September 2010. The goal of this study to estimate the radiation dose and measurement of radioactive contamination of aircraft scrap equipment and increase the culture of radiological safety as well as the concept of radiation protection. The results showed that there is no pollution observed in the contents of the aircraft and the spire part stores outside, levels of radiation dose for the all contents of the aircraft and spire part within the excitable level, except temperature sensors estimated radiation dose about 43 μSv/h outside of the shielding and 12 μSv/h inside the shielding that exceeded the internationally recommended dose level. One of the most important of the identification of eighteen (18) radiation sources used in temperature and fuel level sensors. These are separated from the scrap, collected and stored in safe place. (Author)

  2. Biological responses to low dose rate gamma radiation

    International Nuclear Information System (INIS)

    Magae, Junji; Ogata, Hiromitsu

    2003-01-01

    Linear non-threshold (LNT) theory is a basic theory for radioprotection. While LNT dose not consider irradiation time or dose-rate, biological responses to radiation are complex processes dependent on irradiation time as well as total dose. Moreover, experimental and epidemiological studies that can evaluate LNT at low dose/low dose-rate are not sufficiently accumulated. Here we analyzed quantitative relationship among dose, dose-rate and irradiation time using chromosomal breakage and proliferation inhibition of human cells as indicators of biological responses. We also acquired quantitative data at low doses that can evaluate adaptability of LNT with statistically sufficient accuracy. Our results demonstrate that biological responses at low dose-rate are remarkably affected by exposure time, and they are dependent on dose-rate rather than total dose in long-term irradiation. We also found that change of biological responses at low dose was not linearly correlated to dose. These results suggest that it is necessary for us to create a new model which sufficiently includes dose-rate effect and correctly fits of actual experimental and epidemiological results to evaluate risk of radiation at low dose/low dose-rate. (author)

  3. ''Low dose'' and/or ''high dose'' in radiation protection: A need to setting criteria for dose classification

    International Nuclear Information System (INIS)

    Sohrabi, M.

    1997-01-01

    The ''low dose'' and/or ''high dose'' of ionizing radiation are common terms widely used in radiation applications, radiation protection and radiobiology, and natural radiation environment. Reading the title, the papers of this interesting and highly important conference and the related literature, one can simply raise the question; ''What are the levels and/or criteria for defining a low dose or a high dose of ionizing radiation?''. This is due to the fact that the criteria for these terms and for dose levels between these two extreme quantities have not yet been set, so that the terms relatively lower doses or higher doses are usually applied. Therefore, setting criteria for classification of radiation doses in the above mentioned areas seems a vital need. The author while realizing the existing problems to achieve this important task, has made efforts in this paper to justify this need and has proposed some criteria, in particular for the classification of natural radiation areas, based on a system of dose limitation. (author)

  4. Global DNA methylation responses to low dose radiation exposure

    International Nuclear Information System (INIS)

    Newman, M.R.; Ormsby, R.J.; Blyth, B.J.; Sykes, P.J.; Bezak, E.

    2011-01-01

    Full text: High radiation doses cause breaks in the DNA which are considered the critical lesions in initiation of radiation-induced cancer. However, at very low radiation doses relevant for the general public, the induction of such breaks will be rare, and other changes to the DNA such as DNA methylation which affects gene expression may playa role in radiation responses. We are studying global DNA methylation after low dose radiation exposure to determine if low dose radiation has short- and/or long-term effects on chromatin structure. We developed a sensitive high resolution melt assay to measure the levels of DNA methylation across the mouse genome by analysing a stretch of DNA sequence within Long Interspersed Nuclear Elements-I (LINE I) that comprise a very large proportion of the mouse and human genomes. Our initial results suggest no significant short-term or longterm) changes in global NA methylation after low dose whole-body X-radiation of 10 J1Gyor 10 mGy, with a significant transient increase in NA methylation observed I day after a high dose of I Gy. If the low radiation doses tested are inducing changes in bal DNA methylation, these would appear to be smaller than the variation observed between the sexes and following the general stress of the sham-irradiation procedure itself. This research was funded by the Low Dose Radiation Research Program, Biological and Environmental Research, US DOE, Grant DE-FG02-05ER64104 and MN is the recipient of the FMCF/BHP Dose Radiation Research Scholarship.

  5. Radiation doses and possible radiation effects of low-level, chronic radiation in vegetation

    International Nuclear Information System (INIS)

    Rhoads, W.A.; Franks, L.A.

    1975-01-01

    Measurements were made of radiation doses in soil and vegetation in Pu-contaminated areas at the Nevada Test Site with the objective of investigating low-level, low-energy gamma radiation (with some beta radiation) effects at the cytological or morphological level in native shrubs. In this preliminary investigation, the exposure doses to shrubs at the approximate height of stem apical meristems were estimated from 35 to 140 R for a ten-year period. The gamma exposure dose estimated for the same period was 20.7 percent +- 6.4 percent of that recorded by the dosimeters used in several kinds of field instrument surveys. Hence, a survey instrument reading made at about 25 cm in the tops of shrubs should indicate about 1 / 5 the dosimeter-measured exposures. No cytology has yet been undertaken because of the drought since last winter. (auth)

  6. Radiation Doses to Hanford Workers from Natural Potassium-40

    Energy Technology Data Exchange (ETDEWEB)

    Strom, Daniel J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lynch, Timothy P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Weier, Dennis R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2009-02-01

    The chemical element potassium is an essential mineral in people and is subject to homeostatic regulation. Natural potassium comprises three isotopes, 39K, 40K, and 41K. Potassium-40 is radioactive, with a half life of 1.248 billion years. In most transitions, it emits a β particle with a maximum energy of 0.560 MeV, and sometimes a gamma photon of 1.461 MeV. Because it is ubiquitous, 40K produces radiation dose to all human beings. This report contains the results of new measurements of 40K in 248 adult females and 2,037 adult males performed at the Department of Energy Hanford Site in 2006 and 2007. Potassium concentrations diminish with age, are generally lower in women than in men, and decrease with body mass index (BMI). The average annual effective dose from 40K in the body is 0.149 mSv y-1 for men and 0.123 mSv y-1 women respectively. Averaged over both men and women, the average effective dose per year is 0.136 mSv y-1. Calculated effective doses range from 0.069 to 0.243 mSv y-1 for adult males, and 0.067 to 0.203 mSv y-1 for adult females, a roughly three-fold variation for each gender. The need for dosimetric phantoms with a greater variety of BMI values should be investigated. From our data, it cannot be determined whether the potassium concentration in muscle in people with large BMI values differs from that in people with small BMI values. Similarly, it would be important to know the potassium concentration in other soft tissues, since much of the radiation dose is due to beta radiation, in which the source and target tissues are the same. These uncertainties should be evaluated to determine their consequences for dosimetry.

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

    DEFF Research Database (Denmark)

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

    1977-01-01

    of dose rate (1–1014 rad s−1). Upon irradiation of the film, the profile of the radiation field is registered as a permanent colored image of the dose distribution. Unlike most other types of dyed plastic dose meters, the optical density produced by irradiation is in most cases stable for periods...... of many polymeric systems in industrial radiation processing. The result is that errors due to energy dependence of response of the radiation sensor are effectively reduced, since the spectral sensitivity of the dose meter matches that of the polymer of interest, over a wide range of photon and electron...

  8. Prescribing and evaluating target dose in dose-painting treatment plans

    DEFF Research Database (Denmark)

    Håkansson, Katrin; Specht, Lena; Aznar, Marianne C

    2014-01-01

    BACKGROUND: Assessment of target dose conformity in multi-dose-level treatment plans is challenging due to inevitable over/underdosage at the border zone between dose levels. Here, we evaluate different target dose prescription planning aims and approaches to evaluate the relative merit of such p......-painting and multi-dose-level plans. The tool can be useful for quality assurance of multi-center trials, and for visualizing the development of treatment planning in routine clinical practice....... of such plans. A quality volume histogram (QVH) tool for history-based evaluation is proposed. MATERIAL AND METHODS: Twenty head and neck cancer dose-painting plans with five prescription levels were evaluated, as well as clinically delivered simultaneous integrated boost (SIB) plans from 2010 and 2012. The QVH...

  9. Cancer risk of low dose/low dose rate radiation: a meta-analysis of cancer data of mammals exposed to low doses of radiation

    International Nuclear Information System (INIS)

    Ogata, Hiromitsu; Magae, Junji

    2008-01-01

    Full text: Linear No Threshold (LNT) model is a basic theory for radioprotection, but the adaptability of this hypothesis to biological responses at low doses or at low dose rates is not sufficiently investigated. Simultaneous consideration of the cumulative dose and the dose rate is necessary for evaluating the risk of long-term exposure to ionizing radiation at low dose. This study intends to examine several numerical relationships between doses and dose rates in biological responses to gamma radiation. Collected datasets on the relationship between dose and the incidence of cancer in mammals exposed to low doses of radiation were analysed using meta-regression models and modified exponential (MOE) model, which we previously published, that predicts irradiation time-dependent biological response at low dose rate ionizing radiation. Minimum doses of observable risk and effective doses with a variety of dose rates were calculated using parameters estimated by fitting meta-regression models to the data and compared them with other statistical models that find values corresponding to 'threshold limits'. By fitting a weighted regression model (fixed-effects meta-regression model) to the data on risk of all cancers, it was found that the log relative risk [log(RR)] increased as the total exposure dose increased. The intersection of this regression line with the x-axis denotes the minimum dose of observable risk. These estimated minimum doses and effective doses increased with decrease of dose rate. The goodness of fits of MOE-model depended on cancer types, but the total cancer risk is reduced when dose rates are very low. The results suggest that dose response curve for cancer risk is remarkably affected by dose rate and that dose rate effect changes as a function of dose rate. For scientific discussion on the low dose exposure risk and its uncertainty, the term 'threshold' should be statistically defined, and dose rate effects should be included in the risk

  10. Total dose and dose rate radiation characterization of EPI-CMOS radiation hardened memory and microprocessor devices

    International Nuclear Information System (INIS)

    Gingerich, B.L.; Hermsen, J.M.; Lee, J.C.; Schroeder, J.E.

    1984-01-01

    The process, circuit discription, and total dose radiation characteristics are presented for two second generation hardened 4K EPI-CMOS RAMs and a first generation 80C85 microprocessor. Total dose radiation performance is presented to 10M rad-Si and effects of biasing and operating conditions are discussed. The dose rate sensitivity of the 4K RAMs is also presented along with single event upset (SEU) test data

  11. Patient radiation doses from enteroclysis examinations

    International Nuclear Information System (INIS)

    Hart, D.; Wall, B.F.; Haggett, P.J.; Boardman, P.; Nolan, D.J.

    1994-01-01

    Data relating to patient dose have been acquired for enteroclysis examinations (small bowel enemas) performed at the John Radcliffe Hospital, Oxford, on 23 adult patients. Dose-area products, fluoroscopy times and the number of radiographs taken are used to compare the examination procedure at the Hospital with enteroclysis and barium follow-throughs performed elsewhere. The mean dose-area product for the 23 examinations was 6.8 Gy cm 2 and the mean effective dose was estimated to be 1.5 mSv. These doses are intermediate between those arising from barium meals and barium enemas performed in the same room. (author)

  12. measurement of high dose radiation using yellow perspex dosimeter

    International Nuclear Information System (INIS)

    Thamrin, M Thoyib; Sofyan, Hasnel

    1996-01-01

    Measurement of high dose radiation using yellow perspex dosemeter has been carried out. Dose range used was between 0.1 to 3.0 kGy. Measurement of dose rate against Fricke dosemeter as a standard dose meter From the irradiation of Fricke dosemeter with time variation of 3,6,9,12,15 and 18 minute, it was obtained average dose rate of 955.57 Gy/hour, linear equation of dose was Y= 2.333+15.776 X with its correlation factor r = 0.9999. Measurement result using yellow perspex show that correlation between net optical density and radiation dose was not linear with its equation was ODc exp. [Bo + In(dose).Bi] Value of Bo = -0.215 and Bi=0.5020. From the experiment it was suggested that routine dosimeter (yellow perspex) should be calibrated formerly against standard dosemeters

  13. Audit of radiation dose during balloon mitral valvuloplasty procedure

    International Nuclear Information System (INIS)

    Livingstone, Roshan S; Chandy, Sunil; Peace, B S Timothy; George, Paul; John, Bobby; Pati, Purendra

    2006-01-01

    Radiation doses to patients during cardiological procedures are of concern in the present day scenario. This study was intended to audit the radiation dose imparted to patients during the balloon mitral valvuloplasty (BMV) procedure. Thirty seven patients who underwent the BMV procedure performed using two dedicated cardiovascular machines were included in the study. The radiation doses imparted to patients were measured using a dose area product (DAP) meter. The mean DAP value for patients who underwent the BMV procedure from one machine was 19.16 Gy cm 2 and from the other was 21.19 Gy cm 2 . Optimisation of exposure parameters and radiation doses was possible for one machine with the use of appropriate copper filters and optimised exposure parameters, and the mean DAP value after optimisation was 9.36 Gy cm 2

  14. Audit of radiation dose during balloon mitral valvuloplasty procedure

    Energy Technology Data Exchange (ETDEWEB)

    Livingstone, Roshan S [Department of Radiology, Christian Medical College, Vellore-632004, TN (India); Chandy, Sunil [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India); Peace, B S Timothy [Department of Radiology, Christian Medical College, Vellore-632004, TN (India); George, Paul [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India); John, Bobby [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India); Pati, Purendra [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India)

    2006-12-15

    Radiation doses to patients during cardiological procedures are of concern in the present day scenario. This study was intended to audit the radiation dose imparted to patients during the balloon mitral valvuloplasty (BMV) procedure. Thirty seven patients who underwent the BMV procedure performed using two dedicated cardiovascular machines were included in the study. The radiation doses imparted to patients were measured using a dose area product (DAP) meter. The mean DAP value for patients who underwent the BMV procedure from one machine was 19.16 Gy cm{sup 2} and from the other was 21.19 Gy cm{sup 2}. Optimisation of exposure parameters and radiation doses was possible for one machine with the use of appropriate copper filters and optimised exposure parameters, and the mean DAP value after optimisation was 9.36 Gy cm{sup 2}.

  15. Trends in doses to some UK radiation workers

    International Nuclear Information System (INIS)

    Best, R.J.; Kendall, G.M.; Pook, E.A.; Saunders, P.J.

    1990-01-01

    The NRPB runs a Personal Monitoring Service which issues dosemeters and keeps radiation dose records for over 10 000 workers. This database is a valuable source of information on occupational exposure to radiation though it is likely that in future the Central Index of Dose Information (CIDI) will provide more comprehensive statistics, albeit restricted to radiation workers in the sense of Ionising Radiation Regulations. This note describes doses incurred to the end of 1987 with some preliminary figures for 1988. It does not cover the same ground as earlier reports but gives more details of the structure of the monitored population by age and sex and examines evidence that mean radiation doses are decreasing with time. (author)

  16. Occupational Radiation Dose for Medical Workers at a University Hospital

    Directory of Open Access Journals (Sweden)

    M.H. Nassef

    2017-11-01

    Full Text Available Occupational radiation doses for medical workers from the departments of diagnostic radiology, nuclear medicine, and radiotherapy at the university hospital of King Abdul-Aziz University (KAU were measured and analysed. A total of 100 medical radiation workers were monitored to determine the status of their average annual effective dose. The analysis and the calibration procedures of this study were carried out at the Center for Radiation Protection and Training-KAU. The monitored workers were classified into subgroups, namely, medical staff/supervisors, technicians, and nurses, according to their responsibilities and specialties. The doses were measured using thermo luminescence dosimeters (TLD-100 (LiF:Mg,Ti placed over the lead apron at the chest level in all types of workers except for those in the cath lab, for whom the TLD was placed at the thyroid protective collar. For nuclear medicine, a hand dosimeter was used to measure the hand dose distribution. The annual average effective doses for diagnostic radiology, nuclear medicine, and radiotherapy workers were found to be 0.66, 1.56, and 0.28 mSv, respectively. The results of the measured annual dose were well below the international recommended dose limit of 20 mSv. Keywords: Occupational radiation dose, radiation workers, TLD, radiation protection

  17. Actual survey of dose evaluation method for standardization of radiation therapy techniques. With special reference to display method of radiation doses

    International Nuclear Information System (INIS)

    Kumagai, Kozo; Yoshiura, Takao; Izumi, Takashi; Araki, Fujio; Takada, Takuo; Jingu, Kenichi.

    1994-01-01

    This report presents the results of questionnaire survey for actual conditions of radiation therapy, which was conducted with the aim of establishing the standardization of radiation therapy techniques. Questionnaires were sent to 100 facilities in Japan, and 86 of these answered, consisting of 62 university hospitals, 2 national hospitals, 14 cancer centers, 4 prefectural or municipal hospitals, and 4 other hospitals. In addition to electron beam therapy, the following typical diseases for radiation therapy were selected as standard irradiation models: cancers of the larynx, esophagus, breast, and uterine cervix, and malignant lymphomas. According to these models, questionnaire results are analyzed in terms of the following four items: (1) irradiation procedures, (2) energy used for radiotherapy, (3) the depth for calculating target absorption doses, and (4) points for displaying target absorption doses. (N.K.)

  18. Radiation dose in paediatric cardiac catheterisation: A systematic literature review

    International Nuclear Information System (INIS)

    Gould, R.; McFadden, S.L.; Hughes, C.M.

    2017-01-01

    Objectives: It is believed that children are more sensitive to ionising radiation than adults. This work reviewed the reported radiation dose estimates for paediatric cardiac catheterisation. A systematic literature review was performed by searching healthcare databases for studies reporting radiation dose using predetermined key words relating to children having cardiac catheterisation. The quality of publications was assessed using relevant Critical Appraisal Skills Programme questions and their reported radiation exposures were evaluated. Key findings: It is only in recent years that larger cohort observations have been undertaken. Although radiation dose from paediatric cardiac catheterisation has decreased in recent years, the literature indicated that it remains varied and potentially substantial. Conclusion: Standardisation of weight categories and procedure types such as those recommended by the PiDRL project could help compare current and future radiation dose estimates. - Highlights: • 31 articles reporting radiation dose from paediatric cardiac catheterisation were reviewed. • In recent years, larger cohorts (>1000) have been reported. • Radiation dose to children has been lowered in the last decade but remains varied. • Future dosimetry should be consistent for weight categories and procedure types.

  19. Effects of low dose radiation on tumor-bearing mice

    International Nuclear Information System (INIS)

    Feng Li; Hou Dianjun; Huang Shanying; Deng Daping; Wang Linchao; Cheng Yufeng

    2007-01-01

    Objective: To explore the effects of low-dose radiation on tumor-bearing mice and radiotherapy induced by low-dose radiation. Methods: Male Wistar mice were implanted with Walker-256 sarcoma cells in the right armpit. On day 4, the mice were given 75 mGy whole-body X-ray radiation. From the fifth day, tumor volume was measured, allowing for the creation of a graph depicting tumor growth. Lymphocytes activity in mice after whole-body X-ray radiation with LDR was determinned by FCM. Cytokines level were also determined by ELISA. Results: Compared with the radiotherapy group, tumor growth was significantly slower in the mice pre-exposed to low-dose radiation (P<0.05), after 15 days, the average tumor weight in the mice pre- exposed to low-dose radiation was also significantly lower (P<0.05). Lymphocytes activity and the expression of the CK in mice after whole-body y-ray radiation with LDR increased significantly. Conclusions: Low-dose radiation can markedly improve the immune function of the lymphocyte, inhibit the tumor growth, increase the resistant of the high-dose radiotherapy and enhance the effect of radiotherapy. (authors)

  20. Effective dose equivalents from external radiation due to Chernobyl accident

    International Nuclear Information System (INIS)

    Erkin, V.G.; Debedev, O.V.; Balonov, M.I.; Parkhomenko, V.I.

    1992-01-01

    Summarized data on measurements of individual dose of external γ-sources in 1987-1990 of population of western areas of Bryansk region were presented. Type of distribution of effective dose equivalent, its significance for various professional and social groups of population depending on the type of the house was discussed. Dependences connecting surface soil activity in the populated locality with average dose of external radiation sources were presented. Tendency of dose variation in 1987-1990 was shown

  1. The internal radiation dose calculations based on Chinese mathematical phantom

    International Nuclear Information System (INIS)

    Wang Haiyan; Li Junli; Cheng Jianping; Fan Jiajin

    2006-01-01

    The internal radiation dose calculations built on Chinese facts become more and more important according to the development of nuclear medicine. the MIRD method developed and consummated by the society of Nuclear Medicine (America) is based on the European and American mathematical phantom and can't fit Chinese well. The transport of γ-ray in the Chinese mathematical phantom was simulated with Monte Carlo method in programs as MCNP4C. the specific absorbed fraction (Φ) of Chinese were calculated and the Chinese Φ database was created. The results were compared with the recommended values by ORNL. the method was proved correct by the coherence when the target organ was the same with the source organ. Else, the difference was due to the different phantom and the choice of different physical model. (authors)

  2. Information from the National Institute of Radiation Protection about radiation doses and radiation risks at x-ray screening

    International Nuclear Information System (INIS)

    1975-05-01

    This report gives a specification of data concerning radiation doses and risks at x-ray investigations of lungs. The dose estimations are principally based on measurements performed in 1974 by the National Institute of Radiation Protection. The radiation doses at x-ray screening are of that magnitude that the risk for acute radiation injuries is non-existent. At these low doses it has not either been able to prove that the radiation gives long-range effects as changes in the genes or cancer of late appearance. At considerable higher doses, more than tens of thousands of millirads, a risk of cancer appearance at a small part of all irradiated persons has been proved, based on the assumption that the cancer risk is proportional to the radiation dose. Cancer can thus occure at low radiation doses too. Because of the mass radiography in Sweden 1974 about twenty cases of cancer may appear in the future. (M.S.)

  3. Biological effects of low doses of radiation at low dose rate

    International Nuclear Information System (INIS)

    1996-05-01

    The purpose of this report was to examine available scientific data and models relevant to the hypothesis that induction of genetic changes and cancers by low doses of ionizing radiation at low dose rate is a stochastic process with no threshold or apparent threshold. Assessment of the effects of higher doses of radiation is based on a wealth of data from both humans and other organisms. 234 refs., 26 figs., 14 tabs

  4. Radiation dose distributions due to sudden ejection of cobalt device

    International Nuclear Information System (INIS)

    Abdelhady, Amr

    2016-01-01

    The evaluation of the radiation dose during accident in a nuclear reactor is of great concern from the viewpoint of safety. One of important accident must be analyzed and may be occurred in open pool type reactor is the rejection of cobalt device. The study is evaluating the dose rate levels resulting from upset withdrawal of co device especially the radiation dose received by the operator in the control room. Study of indirect radiation exposure to the environment due to skyshine effect is also taken into consideration in order to evaluate the radiation dose levels around the reactor during the ejection trip. Microshield, SHLDUTIL, and MCSky codes were used in this study to calculate the radiation dose profiles during cobalt device ejection trip inside and outside the reactor building. - Highlights: • This study aims to calculate the dose rate profiles after cobalt device ejection from open-pool-type reactor core. • MicroShield code was used to evaluate the dose rates inside the reactor control room. • McSKY code was used to evaluate the dose rates outside the reactor building. • The calculated dose rates for workers are higher than the permissible limits after 18 s from device ejection.

  5. Evaluation of planning dose accuracy in case of radiation treatment on inhomogeneous organ structure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Yong; Lee, Jae Hee; Kwak, Yong Kook; Ha, Min Yong [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2013-09-15

    We are to find out the difference of calculated dose of treatment planning system (TPS) and measured dose in case of inhomogeneous organ structure. Inhomogeneous phantom is made with solid water phantom and cork plate. CT image of inhomogeneous phantom is acquired. Treatment plan is made with TPS (Pinnacle3 9.2. Royal Philips Electronics, Netherlands) and calculated dose of point of interest is acquired. Treatment plan was delivered in the inhomogeneous phantom by ARTISTE (Siemens AG, Germany) measured dose of each point of interest is obtained with Gafchromic EBT2 film (International Specialty Products, US) in the gap between solid water phantom or cork plate. To simulate lung cancer radiation treatment, artificial tumor target of paraffin is inserted in the cork volume of inhomogeneous phantom. Calculated dose and measured dose are acquired as above. In case of inhomogeneous phantom experiment, dose difference of calculated dose and measured dose is about -8.5% at solid water phantom-cork gap and about -7% lower in measured dose at cork-solid water phantom gap. In case of inhomogeneous phantom inserted paraffin target experiment, dose difference is about 5% lower in measured dose at cork-paraffin gap. There is no significant difference at same material gap in both experiments. Radiation dose at the gap between two organs with different electron density is significantly lower than calculated dose with TPS. Therefore, we must be aware of dose calculation error in TPS and great care is suggested in case of radiation treatment planning on inhomogeneous organ structure.

  6. Evaluation of planning dose accuracy in case of radiation treatment on inhomogeneous organ structure

    International Nuclear Information System (INIS)

    Kim, Chan Yong; Lee, Jae Hee; Kwak, Yong Kook; Ha, Min Yong

    2013-01-01

    We are to find out the difference of calculated dose of treatment planning system (TPS) and measured dose in case of inhomogeneous organ structure. Inhomogeneous phantom is made with solid water phantom and cork plate. CT image of inhomogeneous phantom is acquired. Treatment plan is made with TPS (Pinnacle3 9.2. Royal Philips Electronics, Netherlands) and calculated dose of point of interest is acquired. Treatment plan was delivered in the inhomogeneous phantom by ARTISTE (Siemens AG, Germany) measured dose of each point of interest is obtained with Gafchromic EBT2 film (International Specialty Products, US) in the gap between solid water phantom or cork plate. To simulate lung cancer radiation treatment, artificial tumor target of paraffin is inserted in the cork volume of inhomogeneous phantom. Calculated dose and measured dose are acquired as above. In case of inhomogeneous phantom experiment, dose difference of calculated dose and measured dose is about -8.5% at solid water phantom-cork gap and about -7% lower in measured dose at cork-solid water phantom gap. In case of inhomogeneous phantom inserted paraffin target experiment, dose difference is about 5% lower in measured dose at cork-paraffin gap. There is no significant difference at same material gap in both experiments. Radiation dose at the gap between two organs with different electron density is significantly lower than calculated dose with TPS. Therefore, we must be aware of dose calculation error in TPS and great care is suggested in case of radiation treatment planning on inhomogeneous organ structure

  7. Development of Plant Application Technique of Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-15

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

  8. Development of Plant Application Technique of Low Dose Radiation

    International Nuclear Information System (INIS)

    Chung, Byung Yeoup; Kim, Jae Sung; Lim, Yong Taek

    2007-07-01

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

  9. Mean annual and collective radiation doses of Perm' province personnel

    International Nuclear Information System (INIS)

    Poplavskij, K.K.; Rotenberg, L.I.

    1978-01-01

    The average annual and collective doses of radiation received by personnel of radiologic facilities and by the population of the region under study as a whole are estimated. Tabular data on radiation loads are presented according to the age and sex of personnel and to the type of radiation sources used. The procedure employed in this study allows one to evaluate objectively the conditions of work with sources of ionizing radiation

  10. Tumour induction by small doses of ionised radiation

    International Nuclear Information System (INIS)

    Putten, L.M. van

    1980-01-01

    The effect of low doses of ionised radiation on tumour induction in animals is discussed. It is hypothesised that high doses of radiation can strongly advance tumour induction from the combination of a stimulated cell growth, as a reaction to massive cell killing, and damage to DNA in the cell nuclei. This effect has a limit below which the radiation dose causes a non-significant amount of dead cells. However in animals where through other reasons, a chronic growth stimulation already exists, only one effect, the damage of DNA, is necessary to induce tumours. A linear dose effect without a threshold level applies in these cases. Applying this hypothesis to man indicates that calculating low dose effects by linear extrapolation of high dose effects is nothing more than a reasonable approximation. (C.F.)

  11. Measurement of gamma radiation doses in nuclear power plant environment

    International Nuclear Information System (INIS)

    Bochvar, I.A.; Keirim-Markus, I.B.; Sergeeva, N.A.

    1976-01-01

    Considered are the problems of measuring gamma radiation dose values and the dose distribution in the nuclear power plant area with the aim of estimating the extent of their effect on the population. Presented are the dosimeters applied, their distribution throughout the controlled area, time of measurement. The distribution of gamma radiation doses over the controlled area and the dose alteration with the increase of the distance from the release source are shown. The results of measurements are investigated. The conclusion is made that operating nuclear power plants do not cause any increase in the gamma radiation dose over the area. Recommendations for clarifying the techniques for using dose-meters and decreasing measurement errors are given [ru

  12. Knowledge of medical imaging radiation dose and risk among doctors.

    Science.gov (United States)

    Brown, Nicholas; Jones, Lee

    2013-02-01

    The growth of computed tomography (CT) and nuclear medicine (NM) scans has revolutionised healthcare but also greatly increased population radiation doses. Overuse of diagnostic radiation is becoming a feature of medical practice, leading to possible unnecessary radiation exposures and lifetime-risks of developing cancer. Doctors across all medical specialties and experience levels were surveyed to determine their knowledge of radiation doses and potential risks associated with some diagnostic imaging. A survey relating to knowledge and understanding of medical imaging radiation was distributed to doctors at 14 major Queensland public hospitals, as well as fellows and trainees in radiology, emergency medicine and general practice. From 608 valid responses, only 17.3% correctly estimated the radiation dose from CT scans and almost 1 in 10 incorrectly believed that CT radiation is not associated with any increased lifetime risk of developing cancer. There is a strong inverse relationship between a clinician's experience and their knowledge of CT radiation dose and risks, even among radiologists. More than a third (35.7%) of doctors incorrectly believed that typical NM imaging either does not use ionising radiation or emits doses equal to or less than a standard chest radiograph. Knowledge of CT and NM radiation doses is poor across all specialties, and there is a significant inverse relationship between experience and awareness of CT dose and risk. Despite having a poor understanding of these concepts, most doctors claim to consider them prior to requesting scans and when discussing potential risks with patients. © 2012 The Authors. Journal of Medical Imaging and Radiation Oncology © 2012 The Royal Australian and New Zealand College of Radiologists.

  13. Biological indicators for radiation absorbed dose: a review

    International Nuclear Information System (INIS)

    Paul, S.F.D.; Venkatachalam, P.; Jeevanram, R.K.

    1996-01-01

    Biological dosimetry has an important role to play in assessing the cumulative radiation exposure of persons working with radiation and also in estimating the true dose received during accidents involving external and internal exposure. Various biodosimetric methods have been tried to estimate radiation dose for the above purposes. Biodosimetric methods include cytogenetic, immunological and mutational assays. Each technique has certain advantages and disadvantages. We present here a review of each technique, the actual method used for detection of dose, the sensitivity of detection and its use in long term studies. (author)

  14. Ultraviolet Radiation Dose National Standard of México

    Science.gov (United States)

    Cardoso, R.; Rosas, E.

    2006-09-01

    We present the Ultraviolet (UV) Radiation Dose National Standard for México. The establishment of this measurement reference at Centro Nacional de Metrología (CENAM) eliminates the need of contacting foreign suppliers in the search for traceability towards the SI units when calibrating instruments at 365 nm. Further more, the UV Radiation Dose National Standard constitutes a highly accurate and reliable source for the UV radiation dose measurements performed in medical and cosmetic treatments as in the the food and pharmaceutics disinfection processes, among other.

  15. Radiation doses in buildings containing coal

    International Nuclear Information System (INIS)

    Somlai, J.; Kanyar, B.; Nenyei, A.; Nemeth, Z.; Nemeth, Cs.

    2001-01-01

    Using coal-slag with high concentration of 226 Ra as building material could result excess dose of people living in these dwellings. The gamma dose rate, the radon concentration and the radionuclide concentration of built-in slags were measured in kindergartens, schools and homes of three towns (Ajka, Tatabanya, Varpalota). The absorbed dose rates exceeded significantly the world average (80 nGy/h) and the annual dose reached 3-4 mSv in some cases. The dose coming from radon is significant in the case of slags, which did not originate from power plants but from smaller stoves and furnaces because in these cases the burning temperature is lower, so the radon emanation is higher. The dose in the latter cases could reach 10-20 mSv/year. (author)

  16. Dose/dose-rate responses of shrimp larvae to UV-B radiation

    International Nuclear Information System (INIS)

    Damkaer, D.M.

    1981-01-01

    Previous work indicated dose-rate thresholds in the effects of UV-B on the near-surface larvae of three shrimp species. Additional observations suggest that the total dose response varies with dose-rate. Below 0.002 Wm -2 sub([DNA]) irradiance no significant effect is noted in activity, development, or survival. Beyond that dose-rate threshold, shrimp larvae are significantly affected if the total dose exceeds about 85 Jm -2 sub([DNA]). Predictions cannot be made without both the dose-rate and the dose. These dose/dose-rate thresholds are compared to four-year mean dose/dose-rate solar UV-B irradiances at the experimental site, measured at the surface and calculated for 1 m depth. The probability that the shrimp larvae would receive lethal irradiance is low for the first half of the season of surface occurrence, even with a 44% increase in damaging UV radiation. (orig.)

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

    African Journals Online (AJOL)

    Objective: This dosimetric study is aiming to report the results of the analysis of doses received by target volumes and organs outside the target volumes during the treatment of medulloblastoma patients. And also by comparing the doses reaching the eyes and the lens with the use of different shielding methods.

  18. Radiation dose assessment in space missions. The MATROSHKA experiment

    International Nuclear Information System (INIS)

    Reitz, Guenther

    2010-01-01

    The exact determination of radiation dose in space is a demanding and challenging task. Since January 2004, the International Space Station is equipped with a human phantom which is a key part of the MATROSHKA Experiment. The phantom is furnished with thousands of radiation sensors for the measurement of depth dose distribution, which has enabled the organ dose calculation and has demonstrated that personal dosemeter at the body surface overestimates the effective dose during extra-vehicular activity by more than a factor two. The MATROSHKA results serve to benchmark models and have therefore a large impact on the extrapolation of models to outer space. (author)

  19. Radiation Doses Received by the Irish Population 2014

    International Nuclear Information System (INIS)

    O'Connor, C.; Currivan, L.; Cunningham, N.; Kelleher, K.; Lewis, M.; Long, S.; McGinnity, P.; Smith, V.; McMahon, C.

    2014-06-01

    People are constantly exposed to a variety of sources of both natural and artificial radioactivity. The radiation dose received by the population from such sources is periodically estimated by the Radiological Protection Institute of Ireland RPII. This report is an update of a population dose assessment undertaken in 2008 and includes the most recent data available on the principal radiation exposure pathways. Wherever possible the collective dose and the resulting average annual dose to an individual living in Ireland, based on the most recently published figure for the population of Ireland, have been calculated for each of the pathways of exposure

  20. Radiation Dose for Equipment in the LHC Arcs

    CERN Document Server

    Wittenburg, K; Spickermann, T

    1998-01-01

    Collisions of protons with residual gas molecules or the beam screen installed in the vacuum chamber are the main sources for the radiation dose in the LHC arcs. The dose due to proton-gas collisions depends on gas pressure, energy and intensity of the circulating beam. The dose is about equally distributed along the arc and has been calculated in previous papers. Collisions of particles with the beam screen will take place where the beam size is largest - close to focusing quadrupole magnets. For this paper the radiation doses due to particles hitting the beam screen in a quadrupole were calculated with the shower codes GEANT3.21 and FLUKA96.

  1. Low doses of radiation: epidemiological investigations

    International Nuclear Information System (INIS)

    Dikiy, N.P.; Dovbnya, A.N.; Medvedeva, E.P.

    2013-01-01

    Influence of small dozes of radiation was investigated with the help epidemiologic evidence. Correlation analysis, regression analysis and frequency analysis were used for investigating morbidity of various cancer illnesses. The pollution of the environment and the fallout of radionuclides in 1962 and 1986 years have an influence upon morbidity of cancer. Influence of small dozes of radiation on health of the population is multifactorial. Therefore depending on other adverse external conditions the influence of radiation in small dozes can be increased or is weakened. Such character of influence of radiation in small dozes proposes the differentiated approach at realization of preventive measures. Especially it concerns regions with favorable ecological conditions.

  2. Influence of boundary effects on electron beam dose distribution formation in multilayer targets

    International Nuclear Information System (INIS)

    Kaluska, I.; Zimek, Z.; Lazurik, V.T.; Lazurik, V.M.; Popov, G.F.; Rogov, Y.V.

    2010-01-01

    Computational dosimetry play a significant role in an industrial radiation processing at dose measurements in the product irradiated with electron beams (EB), X-ray and gamma ray from radionuclide sources. Accurate and validated programs for absorbed dose calculations are required for computational dosimetry. The program ModeStEB (modelling of EB processing in a three-dimensional (3D) multilayer flat targets) was designed specially for simulation and optimization of industrial radiation processing, calculation of the 3D absorbed dose distribution within multilayer packages. The package is irradiated with scanned EB on an industrial radiation facility that is based on the pulsed or continuous type of electron accelerators in the electron energy range from 0.1 to 25 MeV. Simulation of EB dose distributions in the multilayer targets was accomplished using the Monte Carlo (MC) method. Experimental verification of MC simulation prediction for EB dose distribution formation in a stack of plates interleaved with polyvinylchloride (PVC) dosimetric films (DF), within a packing box, and irradiated with a scanned 10 MeV EB on a moving conveyer is discussed. (authors)

  3. Natural background radiation and population dose in China

    Energy Technology Data Exchange (ETDEWEB)

    Guangzhi, C. (Ministry of Public Health, Beijing, BJ (China)); Ziqiang, P.; Zhenyum, H.; Yin, Y.; Mingqiang, G.

    On the basis of analyzing the data for the natural background radiation level in China, the typical values for indoor and outdoor terrestrial gamma radiation and effective dose equivalents from radon and thoron daughters are recommended. The annual effective dose equivalent from natural radiation to the inhabitant is estimated to be 2.3 mSv, in which 0.54 mSv is from terrestrial gamma radiation and about 0,8 mSv is from radon and its short-lived daughters. 55 Refs.

  4. The development of remote wireless radiation dose monitoring system

    International Nuclear Information System (INIS)

    Lee, Jin-woo; Jeong, Kyu-hwan; Kim, Jong-il; Im, Chae-wan

    2015-01-01

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

  5. The development of remote wireless radiation dose monitoring system

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  6. Health hazards of low doses of ionizing radiations. Vo. 1

    International Nuclear Information System (INIS)

    El-Naggar, M.A.

    1996-01-01

    Exposure to high doses of ionizing radiation results in clinical manifestations of several disease entities that may be fatal. The onset and severity of these acute radiation syndromes are deterministic in relation to dose magnitude. Exposure to ionizing radiations at low doses and low dose rates could initiate certain damage in critical molecules of the cell, that may develop in time into serious health effects. The incidence of such delayed effects in low, and is only detectable through sophisticated epidemiological models carried out on large populations. The radiation damage induced in critical molecules of cells may develop by stochastic biochemical mechanisms of repair, residual damage, adaptive response, cellular transformation, promotion and progression into delayed health effects, the most important of which is carcinogenesis. The dose response relationship of probabilistic stochastic delayed effects of radiation at low doses and low dose rates, is very complex indeed. The purpose of this review is to provide a comprehensive understanding of the underlying mechanisms, the factors involved, and the uncertainties encountered. Contrary to acute deterministic effects, the occurrence of probabilistic delayed effects of radiation remains to be enigmatic. 7 figs

  7. Reducing ionizing radiation doses during cardiac interventions in pregnant women.

    Science.gov (United States)

    Orchard, Elizabeth; Dix, Sarah; Wilson, Neil; Mackillop, Lucy; Ormerod, Oliver

    2012-09-01

    There is concern over ionizing radiation exposure in women who are pregnant or of child-bearing age. Due to the increasing prevalence of congenital and acquired heart disease, the number of women who require cardiac interventions during pregnancy has increased. We have developed protocols for cardiac interventions in pregnant women and women of child-bearing age, aimed at substantially reducing both fluoroscopy duration and radiation doses. Over five years, we performed cardiac interventions on 15 pregnant women, nine postpartum women and four as part of prepregnancy assessment. Fluoroscopy times were minimized by simultaneous use of intracardiac echocardiography, and by using very low frame rates (2/second) during fluoroscopy. The procedures most commonly undertaken were closure of atrial septal defect (ASD) or patent foramen ovale (PFO) in 16 women, coronary angiograms in seven, right and left heart catheters in three and two stent placements. The mean screening time for all patients was 2.38 minutes (range 0.48-13.7), the median radiation dose was 66 (8.9-1501) Gy/cm(2). The median radiation dose to uterus was 1.92 (0.59-5.47) μGy, and the patient estimated dose was 0.24 (0.095-0.80) mSv. Ionizing radiation can be used safely in the management of severe cardiac structural disease in pregnancy, with very low ionizing radiation dose to the mother and extremely low exposure to the fetus. With experience, ionizing radiation doses at our institution have been reduced.

  8. Quantitative modeling of responses to chronic ionizing radiation exposure using targeted and non-targeted effects.

    Directory of Open Access Journals (Sweden)

    Igor Shuryak

    Full Text Available The biological effects of chronic ionizing radiation exposure can be difficult to study, but important to understand in order to protect the health of occupationally-exposed persons and victims of radiological accidents or malicious events. They include targeted effects (TE caused by ionizations within/close to nuclear DNA, and non-targeted effects (NTE caused by damage to other cell structures and/or activation of stress-signaling pathways in distant cells. Data on radiation damage in animal populations exposed over multiple generations to wide ranges of dose rates after the Chernobyl nuclear-power-plant accident are very useful for enhancing our understanding of these processes. We used a mechanistically-motivated mathematical model which includes TE and NTE to analyze a large published data set on chromosomal aberrations in pond snail (Lymnaea stagnalis embryos collected over 16 years from water bodies contaminated by Chernobyl fallout, and from control locations. The fraction of embryo cells with aberrations increased dramatically (>10-fold and non-linearly over a dose rate range of 0.03-420 μGy/h (0.00026-3.7 Gy/year. NTE were very important for describing the non-linearity of this radiation response: the TE-only model (without NTE performed dramatically worse than the TE+NTE model. NTE were predicted to reach ½ of maximal intensity at 2.5 μGy/h (0.022 Gy/year and to contribute >90% to the radiation response slope at dose rates <11 μGy/h (0.1 Gy/year. Internally-incorporated 90Sr was possibly more effective per unit dose than other radionuclides. The radiation response shape for chromosomal aberrations in snail embryos was consistent with data for a different endpoint: the fraction of young amoebocytes in adult snail haemolymph. Therefore, radiation may affect different snail life stages by similar mechanisms. The importance of NTE in our model-based analysis suggests that the search for modulators of NTE-related signaling pathways

  9. Radiation doses to patients in haemodynamic procedures

    Energy Technology Data Exchange (ETDEWEB)

    Canadillas-Perdomo, B; Catalan-Acosta, A; Hernandez-Armas, J [Servicio de Fisica Medica, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain); Perez-Martin, C [Servicio de Ingenieria Biomedica, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain); Armas-Trujillo, D de [Servicio de Cardiologia, Hospital Universitario de Canarias, La Laguna, Tenerife (Spain)

    2001-03-01

    Interventional radio-cardiology gives high doses to patients due to high values of fluoroscopy times and large series of radiographic images. The main objective of the present work is the determination of de dose-area product (DAP) in patients of three different types of cardiology procedures with X-rays. The effective doses were estimated trough the organ doses values measured with thermoluminescent dosimeters (TLDs-100), suitable calibrated, placed in a phantom type Rando which was submitted to the same radiological conditions corresponding to the procedures made on patients. The values for the effective doses in the procedures CAD Seldinger was 6.20 mSv on average and 1.85mSv for pacemaker implants. (author)

  10. Radiation doses to patients in haemodynamic procedures

    International Nuclear Information System (INIS)

    Canadillas-Perdomo, B.; Catalan-Acosta, A.; Hernandez-Armas, J.; Perez-Martin, C.; Armas-Trujillo, D. de

    2001-01-01

    Interventional radio-cardiology gives high doses to patients due to high values of fluoroscopy times and large series of radiographic images. The main objective of the present work is the determination of de dose-area product (DAP) in patients of three different types of cardiology procedures with X-rays. The effective doses were estimated trough the organ doses values measured with thermoluminescent dosimeters (TLDs-100), suitable calibrated, placed in a phantom type Rando which was submitted to the same radiological conditions corresponding to the procedures made on patients. The values for the effective doses in the procedures CAD Seldinger was 6.20 mSv on average and 1.85mSv for pacemaker implants. (author)

  11. Doses and biological effect of ionizing radiation

    International Nuclear Information System (INIS)

    Hrynkiewicz, A.

    1993-01-01

    The aim of the monograph is to review practical aspects of dosimetry. The work describes basic units which are used in dosimetry and natural as well as industrial sources of ionizing radiation. Information given in the monograph help in assessment of the radiation risk. 8 refs, 15 tabs

  12. Biological effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Gonzalez, A.J.

    1994-01-01

    Few weeks ago, when the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) submitted to the U.N. General Assembly the UNSCEAR 1994 report, the international community had at its disposal a broad view of the biological effects of low doses of ionizing radiation. The 1994 report (272 pages) specifically addressed the epidemiological studies of radiation carcinogenesis and the adaptive responses to radiation in cells and organisms. The report was aimed to supplement the UNSCEAR 1993 report to the U.N. General Assembly- an extensive document of 928 pages-which addressed the global levels of radiation exposing the world population, as well as some issues on the effects of ionizing radiation, including: mechanisms of radiation oncogenesis due to radiation exposure, influence of the level of dose and dose rate on stochastic effects of radiation, hereditary effects of radiation effects on the developing human brain, and the late deterministic effects in children. Those two UNSCEAR reports taken together provide an impressive overview of current knowledge on the biological effects of ionizing radiation. This article summarizes the essential issues of both reports, although it cannot cover all available information. (Author)

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

    Science.gov (United States)

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

  14. Studying and measuring the gamma radiation doses in Homs city

    International Nuclear Information System (INIS)

    Sofaan, A. H.

    2001-01-01

    The gamma radiation dose was measured in Homs city by using many portable dosimeters (electronic dosimeter and Geiger-Muller). The measurements were carried out in the indoor and outdoor buildings, for different time period, through one year (1999-2000). High purity germanium detector with low back ground radiation (HpGe) was used to determine radiation element contained in some building and the surrounding soil. The statistical analysis laws were applied to make sure that the measured dose distribution around average value is normal distribution. The measurement indicates that the gamma indoor dose varies from 312μSv/y to 511μSv/y, with the average annual dose of 385μSv/y. However the gamma outdoor dose rate varies from 307μSv/y to 366μSv/y with an average annual dose 385μSv/y. The annual outdoor gamma radiation dose is about %16 lower than the outdoor dose in Homs City. These measurements have indicated that environmental gamma doses in Homs City are relatively low. This is because that most of the soils and rocks in the area are limestone. (author)

  15. Natural radiation level and doses to population in Anhui province

    International Nuclear Information System (INIS)

    1985-01-01

    The absorbed dose rates in air 1 m above the ground from natural radiation and terrestrial gamma radiation in Anhui Province were surveyed. One measurement was made in every area of 90 km 2 . The absorbed dose rates in air from terrestrial radiation range from 54 to 90 nGy.h -1 with an average of 70 nGy.h -1 . The ratios of indoors-to-outdoors and of roads-to-outdoors are 1.5 and 0.9 respectively. The annual effective dose equivalent from external radiation is 0.68-1.05 mSv. The population-weighted average values for mountain area, plain, hilly land, and the Changjiang River basin as well as the annual collective effective dose equivalent were calculated

  16. establishment of background radiation dose rate in the vicinity

    African Journals Online (AJOL)

    nb

    radiation dose rate data prior to commencement of uranium mining activities. Twenty stations in seven ... and geological structures of soil and rocks. (Florou and Kritids 1992, ... Selection of Sampling Points and location of. Field Dosimeters.

  17. The Spanish National Dose Registry and Spanish radiation passbooks

    International Nuclear Information System (INIS)

    Hernandez, A.; Martin, A.; Villanueva, I.; Amor, I.; Butragueno, J.L.

    2001-01-01

    The Spanish National Dose Registry (BDN) is the Nuclear Safety Council's (CSN) national database of occupational exposure to radiation. Each month BDN receives records of individual external doses from approved dosimetry services. The dose records include information regarding the occupational activities of exposed workers. The dose information and the statistical analysis prepared by the BDN are a useful tool for effective operational protection of occupationally exposed workers and a support for the CSN in the development and application of the ALARA principle. The Spanish radiation passbook was introduced in 1990 and since then CSN, as regulatory authority, has required that all outside workers entering controlled areas should have radiation passbooks. Nowadays, CSN has implemented improvements in the Spanish radiation Passbooks, taking into account previous experience and Directive 96/29/EURATOM. (author)

  18. Online Radiation Dose Measurement System for ATLAS experiment

    CERN Document Server

    Mandić, I; The ATLAS collaboration

    2012-01-01

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

  19. Multidisciplinary European Low Dose Initiative (MELODI). Strategic research agenda for low dose radiation risk research

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, M. [Federal Office for Radiation Protection, BfS, Department of Radiation Protection and Health, Neuherberg (Germany); Auvinen, A. [University of Tampere, Tampere (Finland); STUK, Helsinki (Finland); Cardis, E. [ISGlobal, Barcelona Institute for Global Health, Barcelona (Spain); Durante, M. [Institute for Fundamental Physics and Applications, TIFPA, Trento (Italy); Harms-Ringdahl, M. [Stockholm University, Centre for Radiation Protection Research, Stockholm (Sweden); Jourdain, J.R. [Institute for Radiological Protection and Nuclear Safety, IRSN, Fontenay-aux-roses (France); Madas, B.G. [MTA Centre for Energy Research, Environmental Physics Department, Budapest (Hungary); Ottolenghi, A. [University of Pavia, Physics Department, Pavia (Italy); Pazzaglia, S. [Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome (Italy); Prise, K.M. [Queens University Belfast, Belfast (United Kingdom); Quintens, R. [Belgian Nuclear Research Centre, SCK-CEN, Mol (Belgium); Sabatier, L. [French Atomic Energy Commission, CEA, Paris (France); Bouffler, S. [Public Health England, PHE, Chilton (United Kingdom)

    2018-03-15

    MELODI (Multidisciplinary European Low Dose Initiative) is a European radiation protection research platform with focus on research on health risks after exposure to low-dose ionising radiation. It was founded in 2010 and currently includes 44 members from 18 countries. A major activity of MELODI is the continuous development of a long-term European Strategic Research Agenda (SRA) on low-dose risk for radiation protection. The SRA is intended to identify priorities for national and European radiation protection research programs as a basis for the preparation of competitive calls at the European level. Among those key priorities is the improvement of health risk estimates for exposures close to the dose limits for workers and to reference levels for the population in emergency situations. Another activity of MELODI is to ensure the availability of European key infrastructures for research activities, and the long-term maintenance of competences in radiation research via an integrated European approach for training and education. The MELODI SRA identifies three key research topics in low dose or low dose-rate radiation risk research: (1) dose and dose rate dependence of cancer risk, (2) radiation-induced non-cancer effects and (3) individual radiation sensitivity. The research required to improve the evidence base for each of the three key topics relates to three research lines: (1) research to improve understanding of the mechanisms contributing to radiogenic diseases, (2) epidemiological research to improve health risk evaluation of radiation exposure and (3) research to address the effects and risks associated with internal exposures, differing radiation qualities and inhomogeneous exposures. The full SRA and associated documents can be downloaded from the MELODI website (http://www.melodi-online.eu/sra.html). (orig.)

  20. KERMA-based radiation dose management system for real-time patient dose measurement

    Science.gov (United States)

    Kim, Kyo-Tae; Heo, Ye-Ji; Oh, Kyung-Min; Nam, Sang-Hee; Kang, Sang-Sik; Park, Ji-Koon; Song, Yong-Keun; Park, Sung-Kwang

    2016-07-01

    Because systems that reduce radiation exposure during diagnostic procedures must be developed, significant time and financial resources have been invested in constructing radiation dose management systems. In the present study, the characteristics of an existing ionization-based system were compared to those of a system based on the kinetic energy released per unit mass (KERMA). Furthermore, the feasibility of using the KERMA-based system for patient radiation dose management was verified. The ionization-based system corrected the effects resulting from radiation parameter perturbations in general radiography whereas the KERMA-based system did not. Because of this difference, the KERMA-based radiation dose management system might overestimate the patient's radiation dose due to changes in the radiation conditions. Therefore, if a correction factor describing the correlation between the systems is applied to resolve this issue, then a radiation dose management system can be developed that will enable real-time measurement of the patient's radiation exposure and acquisition of diagnostic images.

  1. An international intercomparison of absorbed dose measurements for radiation therapy

    International Nuclear Information System (INIS)

    Taiman Kadni; Noriah Mod Ali

    2002-01-01

    Dose intercomparison on an international basis has become an important component of quality assurance measurement i.e. to check the performance of absorbed dose measurements in radiation therapy. The absorbed dose to water measurements for radiation therapy at the SSDL, MINT have been regularly compared through international intercomparison programmes organised by the IAEA Dosimetry Laboratory, Seibersdorf, Austria such as IAEA/WHO TLD postal dose quality audits and the Intercomparison of therapy level ionisation chamber calibration factors in terms of air kerma and absorbed dose to water calibration factors. The results of these intercomparison in terms of percentage deviations for Cobalt 60 gamma radiation and megavoltage x-ray from medical linear accelerators participated by the SSDL-MINT during the year 1985-2001 are within the acceptance limit. (Author)

  2. Assessment of cosmic radiation doses received by air crew

    International Nuclear Information System (INIS)

    McAulay, I.R.

    1998-01-01

    Cosmic radiation in the atmosphere is such a complex mixture of radiation type that it is difficult to get a single instrument which is suitable for such measurements. Passive devices such as film badges and track etch detectors have also been used, but again present difficulties of interpretation and requirements of multiple devices to accommodate the different types of radiation encountered. In summary, air crew are the occupational group most highly exposed to radiation. The radiation doses experienced by them are sufficiently high as to require assessment on a regular basis and possible control by appropriate rostering. There appears little possibility of the dose limit for workers being exceeded, except possibly in the case of pregnant female crew. This category of air crew should be the subject of special controls aimed at ensuring that the dose limits for the foetus should not be exceeded

  3. Iodine 131 therapy patients: radiation dose to staff

    International Nuclear Information System (INIS)

    Castronovo, F.P. Jr.; Beh, R.A.; Veilleux, N.M.

    1986-01-01

    Metastasis to the skeletal system from follicular thyroid carcinoma may be treated with an oral dose of 131 I-NaI. Radiation exposures to hospital personnel attending these patients were calculated as a function of administered dose, distance from the patient and time after administration. Routine or emergency patient handling tasks would not exceed occupational radiation protection guidelines for up to 30 min immediately after administration. The emergency handling of several patients presents the potential for exceeding these guidelines. (author)

  4. Monitoring of radiation exposure and registration of doses

    International Nuclear Information System (INIS)

    1996-01-01

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

  5. Painting Dose: The ART of Radiation

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

  6. Painting Dose: The ART of Radiation

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    International Nuclear Information System (INIS)

    Sulieman, A.; Habiballah, B.; Abdelaziz, I.; Alzimami, K.; Osman, H.; Omer, H.; Sassi, S. A.

    2014-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

  9. The health effects of low-dose ionizing radiation

    International Nuclear Information System (INIS)

    Dixit, A.N.; Dixit, Nishant

    2012-01-01

    It has been established by various researches, that high doses of ionizing radiation are harmful to health. There is substantial controversy regarding the effects of low doses of ionizing radiation despite the large amount of work carried out (both laboratory and epidemiological). Exposure to high levels of radiation can cause radiation injury, and these injuries can be relatively severe with sufficiently high radiation doses. Prolonged exposure to low levels of radiation may lead to cancer, although the nature of our response to very low radiation levels is not well known at this time. Many of our radiation safety regulations and procedures are designed to protect the health of those exposed to radiation occupationally or as members of the public. According to the linear no-threshold (LNT) hypothesis, any amount, however small, of radiation is potentially harmful, even down to zero levels. The threshold hypothesis, on the other hand, emphasizes that below a certain threshold level of radiation exposure, any deleterious effects are absent. At the same time, there are strong arguments, both experimental and epidemiological, which support the radiation hormesis (beneficial effects of low-level ionizing radiation). These effects cannot be anticipated by extrapolating from harmful effects noted at high doses. Evidence indicates an inverse relationship between chronic low-dose radiation levels and cancer incidence and/or mortality rates. Examples are drawn from: 1) state surveys for more than 200 million people in the United States; 2) state cancer hospitals for 200 million people in India; 3) 10,000 residents of Taipei who lived in cobalt-60 contaminated homes; 4) high-radiation areas of Ramsar, Iran; 5) 12 million person-years of exposed and carefully selected control nuclear workers; 6) almost 300,000 radon measurements of homes in the United States; and 7) non-smokers in high-radon areas of early Saxony, Germany. This evidence conforms to the hypothesis that

  10. Radiation dose exposure in patients affected by lymphoma undergoing repeat CT examinations: how to manage the radiation dose variability.

    Science.gov (United States)

    Paolicchi, Fabio; Bastiani, Luca; Guido, Davide; Dore, Antonio; Aringhieri, Giacomo; Caramella, Davide

    2018-03-01

    To assess the variability of radiation dose exposure in patients affected by lymphoma undergoing repeat CT (computed tomography) examinations and to evaluate the influence of different scan parameters on the overall radiation dose. A series of 34 patients (12 men and 22 women with a median age of 34.4 years) with lymphoma, after the initial staging CT underwent repeat follow-up CT examinations. For each patient and each repeat examination, age, sex, use of AEC system (Automated Exposure Control, i.e. current modulation), scan length, kV value, number of acquired scans (i.e. number of phases), abdominal size diameter and dose length product (DLP) were recorded. The radiation dose of just one venous phase was singled out from the DLP of the entire examination. All scan data were retrieved by our PACS (Picture Archiving and Communication System) by means of a dose monitoring software. Among the variables we considered, no significant difference of radiation dose was observed among patients of different ages nor concerning tube voltage. On the contrary the dose delivered to the patients varied depending on sex, scan length and usage of AEC. No significant difference was observed depending on the behaviour of technologists, while radiologists' choices had indirectly an impact on the radiation dose due to the different number of scans requested by each of them. Our results demonstrate that patients affected by lymphoma who undergo repeat whole body CT scanning may receive unnecessary overexposure. We quantified and analyzed the most relevant variables in order to provide a useful tool to manage properly CT dose variability, estimating the amount of additional radiation dose for every single significant variable. Additional scans, incorrect scan length and incorrect usage of AEC system are the most relevant cause of patient radiation exposure.

  11. Internal dose assessment in radiation accidents

    International Nuclear Information System (INIS)

    Toohey, R.E.

    2003-01-01

    Although numerous models have been developed for occupational and medical internal dosimetry, they may not be applicable to an accident situation. Published dose coefficients relate effective dose to intake, but if acute deterministic effects are possible, effective dose is not a useful parameter. Consequently, dose rates to the organs of interest need to be computed from first principles. Standard bioassay methods may be used to assess body contents, but, again, the standard models for bioassay interpretation may not be applicable because of the circumstances of the accident and the prompt initiation of decorporation therapy. Examples of modifications to the standard methodologies include adjustment of biological half-times under therapy, such as in the Goiania accident, and the same effect, complicated by continued input from contaminated wounds, in the Hanford 241 Am accident. (author)

  12. Pediatric radiation dose management in digital radiography

    International Nuclear Information System (INIS)

    Neitzel, U.

    2004-01-01

    Direct digital radiography (DR) systems based on flat-panel detectors offer improved dose management in pediatric radiography. Integration of X-ray generation and detection in one computer-controlled system provides better control and monitoring

  13. Cosmic radiation dose in aircraft - a neutron track etch detector

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, B.; Radolic, V.; Miklavcic, I.; Poje, M.; Varga, M. [Department of Physics, University of Osijek, 31000 Osijek, P.O. Box 125, Gajev trg 6 (Croatia); Planinic, J. [Department of Physics, University of Osijek, 31000 Osijek, P.O. Box 125, Gajev trg 6 (Croatia)], E-mail: planinic@ffos.hr

    2007-12-15

    Cosmic radiation bombards us at high altitude by ionizing particles. The radiation environment is a complex mixture of charged particles of solar and galactic origin, as well as of secondary particles produced in interaction of the galactic cosmic particles with the nuclei of atmosphere of the Earth. The radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard ATR 42 and A 320 aircrafts (flight level of 8 and 11 km, respectively) was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter. The estimated occupational effective dose for the aircraft crew (A 320) working 500 h per year was 1.64 mSv. Other experiments, or dose rate measurements with the neutron dosimeter, consisting of LR-115 track detector and boron foil BN-1 or 10B converter, were performed on five intercontinental flights. Comparison of the dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level showed that the neutron component carried about 50% of the total dose. The dose rate measurements on the flights from the Middle Europe to the South and Middle America, then to Korea and Japan, showed that the flights over or near the equator region carried less dose rate; this was in accordance with the known geomagnetic latitude effect.

  14. Cosmic radiation dose in aircraft - a neutron track etch detector

    International Nuclear Information System (INIS)

    Vukovic, B.; Radolic, V.; Miklavcic, I.; Poje, M.; Varga, M.; Planinic, J.

    2007-01-01

    Cosmic radiation bombards us at high altitude by ionizing particles. The radiation environment is a complex mixture of charged particles of solar and galactic origin, as well as of secondary particles produced in interaction of the galactic cosmic particles with the nuclei of atmosphere of the Earth. The radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard ATR 42 and A 320 aircrafts (flight level of 8 and 11 km, respectively) was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter. The estimated occupational effective dose for the aircraft crew (A 320) working 500 h per year was 1.64 mSv. Other experiments, or dose rate measurements with the neutron dosimeter, consisting of LR-115 track detector and boron foil BN-1 or 10B converter, were performed on five intercontinental flights. Comparison of the dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level showed that the neutron component carried about 50% of the total dose. The dose rate measurements on the flights from the Middle Europe to the South and Middle America, then to Korea and Japan, showed that the flights over or near the equator region carried less dose rate; this was in accordance with the known geomagnetic latitude effect

  15. 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.)

  16. 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.

  17. Individual radiation doses. Annual report 1995

    International Nuclear Information System (INIS)

    Bergman, L.

    1995-05-01

    During the year we measured whole body doses on 10226 bearers, distributed as follows: 0-0,5 mSv on 8816 persons, 0,6-1,0 mSv on 693 persons, 1,1-5,0 on 678 persons, >5 mSv on 39 persons. At higher dose than 4 mSv/4 weeks, the reason to the irradiation will be investigated. 2 figs, 2 tabs

  18. Radiation dose modeling using IGRIP and Deneb/ERGO

    International Nuclear Information System (INIS)

    Vickers, D.S.; Davis, K.R.; Breazeal, N.L.; Watson, R.A.; Ford, M.S.

    1995-01-01

    The Radiological Environment Modeling System (REMS) quantifies dose to humans in radiation environments using the IGRIP (Interactive Graphical Robot Instruction Program) and Deneb/ERGO (Ergonomics) simulation software products. These commercially available products are augmented with custom C code to provide the radiation exposure information to and collect the radiation dose information from the workcell simulations. The emphasis of this paper is on the IGRIP and Deneb/ERGO parts of REMS, since that represents the extension to existing capabilities developed by the authors. Through the use of any radiation transport code or measured data, a radiation exposure input database may be formulated. User-specified IGRIP simulations utilize these database files to compute and accumulate dose to human devices (Deneb's ERGO human) during simulated operations around radiation sources. Timing, distances, shielding, and human activity may be modeled accurately in the simulations. The accumulated dose is recorded in output files, and the user is able to process and view this output. REMS was developed because the proposed reduction in the yearly radiation exposure limit will preclude or require changes in many of the manual operations currently being utilized in the Weapons Complex. This is particularly relevant in the area of dismantlement activities at the Pantex Plant in Amarillo, TX. Therefore, a capability was needed to be able to quantify the dose associated with certain manual processes so that the benefits of automation could be identified and understood

  19. Measurement of radiation dose in dental radiology

    International Nuclear Information System (INIS)

    Helmrot, E.; Carlsson, G. A.

    2005-01-01

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

  20. Radiation doses from computed tomography in Australia

    International Nuclear Information System (INIS)

    Thomson, J.E.M.; Tingey, D.R.C.

    1996-01-01

    Recent surveys in the UK and New Zealand have shown that although the number of CT examinations small compared to conventional Radiology, CT contributes about 20% to the overall dose from diagnostic radiology. In view of these findings and the rapid increase in the number of CT facilities in recent years, a survey of the number of facilities, frequency of examination, techniques and patient doses has been performed. Australia, with 329 units is well endowed with CT equipment compared to European Countries and New Zealand. For many examinations a wide range was found in the number of slices and slice widths used and this led to a large spread in the corresponding doses. Assuming the practices of the non-responders are statistically similar to those who responded, some preliminary estimates of population doses can be made. There could be as many as 1.1 million CT examinations each year in Australia resulting in a per capur effectie dose of 0.36 mSv. Although the results of this survey are still subject to some refinement, they indicate that CT is a major, and possibly the dominant, contributor to doses from diagnostic radiology in Australia. (author)

  1. An epidemiological study for the reduction of population radiation dose

    International Nuclear Information System (INIS)

    Gamo, Makoto

    1989-01-01

    The correlation of tube voltage with patient exposure was studied using effective dose as an indicator of dose reduction in intraoral radiography. The results were as follows: l. The salivary gland tissues contributed the most to the effective dose of intraoral radiography. 2. In the 50 to 90 kV range, there was no appreciable correlation between tube voltage and effective dose. 3. Therefore, it was suggested that adjusting the tube voltage for maximum image quality does not effect radiation protection. 4. This study reconfirmed the fact that increases in voltages up to 90 kV reduce skin doses. (author)

  2. Radiation doses to personnel in clinics for gynecologic oncology

    International Nuclear Information System (INIS)

    Forsberg, B.; Spanne, P.

    1985-01-01

    Radium or Cesium is used for radiotherapy of gynecologic cancer at six clinics in Sweden. This report gives a survey of the radiation doses the personnel is exposed to. The measurement were performed using TL-dosimeters. The dose equivalents for different parts of the body at specific working moments was deduced as well as the effective dose equivalent and the collective dose equivalent. 1983 the total collective dose equivalent for the six clinics was 1.3 manSv, which corresponds to 3.9 manmSv/g equivalent mass of Radium used at the treatments. (With 11 tables and 10 figures) (L.E.)

  3. Radiation shielding and dose rate distribution for the building of the high dose rate accelerator

    International Nuclear Information System (INIS)

    Matsuda, Koji; Takagaki, Torao; Nakase, Yoshiaki; Nakai, Yohta.

    1984-03-01

    A high dose rate electron accelerator was established at Osaka Laboratory for Radiation Chemistry, Takasaki Establishment, JAERI in the fiscal year of 1975. This report shows the fundamental concept for the radiation shielding of the accelerator building and the results of their calculations which were evaluated through the model experiments. After the construction of the building, the leak radiation was measured in order to evaluate the calculating method of radiation shielding. Dose rate distribution of X-rays was also measured in the whole area of the irradiation room as a data base. (author)

  4. High-dose preoperative radiation for cancer of the rectum: Impact of radiation dose on patterns of failure and survival

    International Nuclear Information System (INIS)

    Ahmad, N.R.; Mohiuddin, M.; Marks, G.

    1993-01-01

    A variety of dose-time schedules are currently used for preoperative radiation therapy of rectal cancer. An analysis of patients treated with high-dose preoperative radiation therapy was undertaken to determine the influence of radiation dose on the patterns of failure, survival, and complications. Two hundred seventy-five patients with localized rectal cancer were treated with high-dose preoperative radiation therapy. One hundred fifty-six patients received 45 Gy (low-dose group). Since 1985, 119 patients with clinically unfavorable cancers were given a higher dose, 55 Gy using a shrinking field technique (high-dose group). All patients underwent curative resection. Median follow-up was 66 months in the low-dose group and 28 months in the high-dose group. Patterns of failure, survival, and complications were analyzed as a function of radiation dose. Fourteen percent of the total group developed a local recurrence; 20% in the low-dose group as compared with 6% in the high-dose group. The actuarial local recurrence rate at 5 years was 20% for the low-dose group and 8% for the high-dose group, and approached statistical significance with p = .057. For tethered/fixed tumors the actuarial local recurrence rates at 5 years were 28% and 9%, respectively, with p = .05. Similarly, for low-lying tumors (less than 6 cm from the anorectal junction) the rates were 24% and 9%, respectively, with p = .04. The actuarial rate of distant metastasis was 28% in the low-dose group and 20% in the high-dose group and was not significantly different. Overall actuarial 5-year survival for the total group of patients was 66%. No significant difference in survival was observed between the two groups, despite the higher proportion of unfavorable cancers in the high-dose group. The incidence of complications was 2%, equally distributed between the two groups. High-dose preoperative radiation therapy for rectal cancer results in excellent local control rates. 27 refs., 2 figs., 8 tabs

  5. Estimation of radiation dose received by the radiation workers during radiographic testing

    International Nuclear Information System (INIS)

    Mohammed, N. A. H. O.

    2013-08-01

    This study was conducted primarily to evaluate occupational radiation dose in industrial radiography during radiographic testing at Balil-Hadida, with the aim of building up baseline data on radiation exposure in the industrial radiography practice in Sudan. Dose measurements during radiographic testing were performed and compared with IAEA reference dose. In this research the doses measured by using hand held radiation survey meter and personal monitoring dosimeter. The results showed that radiation doses ranged between minimum (0.448 mSv/ 3 month) , and maximum (1.838 mSv / 3 month), with an average value (0.778 mSv/ 3 month), and the standard deviation 0.292 for the workers used gamma mat camera. The analysis of data showed that the radiation dose for all radiation worker are receives less than annual limit for exposed workers 20 mSv/ year and compare with other study found that the dose received while body doses ranging from 0.1 to 9.4 mSv/ year, work area design in all the radiography site followed the three standard rules namely putting radiation signs, reducing access to control area and making of boundaries. Thus the accidents arising from design faults not likely to occur at these site. Results suggest that adequate fundamental training of radiation workers in general radiography prior to industrial radiography work will further improve the standard of personnel radiation protection. (Author)

  6. Risks to health from radiation at low dose rates

    International Nuclear Information System (INIS)

    Gentner, N.E.; Osborne, R.V.

    1997-01-01

    Our focus is on whether, using a balance-of-evidence approach, it is possible to say that at a low enough dose, or at a sufficiently low dose rate, radiation risk reduces to zero in a population. We conclude that insufficient evidence exists at present to support such a conclusion. In part this reflects statistical limitations at low doses, and in part (although mechanisms unquestionably exist to protect us against much of the damage induced by ionizing radiation) the biological heterogeneity of human populations, which means these mechanisms do not act in all members of the population at all times. If it is going to be possible to demonstrate that low doses are less dangerous than we presently assume, the evidence, paradoxically, will likely come from studies of higher dose and dose rate scenarios than are encountered occupationally. (author)

  7. The Effect of NPP's Stack Height to Radiation Dose

    International Nuclear Information System (INIS)

    Pandi, Liliana Yetta; Rohman, Budi

    2003-01-01

    The purpose of dose calculation for accidents is to analyze the capability of NPP to maintain the safety of public and workers in case an accident occurs on the Plant in a site. This paper calculates the Loss of Coolant Accident in PWR plant. The calculation results shows that no risks of serious radiation exposure are given to the neighboring public even if such a large accident occurred, and the effect of stack height can be predicted by analysis of the calculation results. The whole dose is calculated for some location (100 m, 300 m, 500 m, 700 m, 900 m, 1500 m, and 2000 m) with three difference stack height i.e. 0 m, 40 m and 100 m. The result of the whole dose calculation is under permitted criteria for whole dose : 0.25 Sv and thyroid dose : 3.0 Sv. The calculation of radiation dose in this paper use EEDCDQ code

  8. Effect of low doses of ionizing radiation on human health

    International Nuclear Information System (INIS)

    Kovalenko, A.N.

    1990-01-01

    Data are reported on the possible mechanism of biological effects of low doses of ionizing radiation on the human body. The lesioning effect of this radiation resulted in some of the persons in the development of disorders of the function of information and vegetative-regulatory systems determined as a desintegration syndrome. This syndrome is manifested in unspecific neuro-vegetative disorders of the function of most important physiological and homeostatic system of the body leading to weakening of the processes of compensation and adaptation. This condition is characterized by an unspecific radiation syndrome as distinct from acute or chronic radiation disease which is a specific radiation syndrome

  9. The choice of food consumption rates for radiation dose assessments

    International Nuclear Information System (INIS)

    Simmonds, J.R.; Webb, G.A.M.

    1981-01-01

    The practical problem in estimating radiation doses due to radioactive contamination of food is the choice of the appropriate food intakes. To ensure compliance or to compare with dose equivalent limits, higher than average intake rates appropriate to critical groups should be used. However for realistic estimates of health detriment in the whole exposed population, average intake rates are more appropriate. (U.K.)

  10. Radiation doses from computed tomography practice in Johor Bahru, Malaysia

    International Nuclear Information System (INIS)

    Karim, M.K.A.; Hashim, S.; Bradley, D.A; Bakar, K.A.; Haron, M.R.; Kayun, Z.

    2016-01-01

    Radiation doses for Computed Tomography (CT) procedures have been reported, encompassing a total of 376 CT examinations conducted in one oncology centre (Hospital Sultan Ismail) and three diagnostic imaging departments (Hospital Sultanah Aminah, Hospital Permai and Hospital Sultan Ismail) at Johor hospital's. In each case, dose evaluations were supported by data from patient questionnaires. Each CT examination and radiation doses were verified using the CT EXPO (Ver. 2.3.1, Germany) simulation software. Results are presented in terms of the weighted computed tomography dose index (CTDI w ), dose length product (DLP) and effective dose (E). The mean values of CTDI w , DLP and E were ranged between 7.6±0.1 to 64.8±16.5 mGy, 170.2±79.2 to 943.3±202.3 mGy cm and 1.6±0.7 to 11.2±6.5 mSv, respectively. Optimization techniques in CT are suggested to remain necessary, with well-trained radiology personnel remaining at the forefront of such efforts. - Highlights: • We investigate radiation doses received by patients from CT scan examinations. • We compare data with current national diagnostic reference levels and other references. • Radiation doses from CT were influenced by CT parameter, scanning techniques and patient characteristics.

  11. Radiation Parameters of High Dose Rate Iridium -192 Sources

    Science.gov (United States)

    Podgorsak, Matthew B.

    A lack of physical data for high dose rate (HDR) Ir-192 sources has necessitated the use of basic radiation parameters measured with low dose rate (LDR) Ir-192 seeds and ribbons in HDR dosimetry calculations. A rigorous examination of the radiation parameters of several HDR Ir-192 sources has shown that this extension of physical data from LDR to HDR Ir-192 may be inaccurate. Uncertainty in any of the basic radiation parameters used in dosimetry calculations compromises the accuracy of the calculated dose distribution and the subsequent dose delivery. Dose errors of up to 0.3%, 6%, and 2% can result from the use of currently accepted values for the half-life, exposure rate constant, and dose buildup effect, respectively. Since an accuracy of 5% in the delivered dose is essential to prevent severe complications or tumor regrowth, the use of basic physical constants with uncertainties approaching 6% is unacceptable. A systematic evaluation of the pertinent radiation parameters contributes to a reduction in the overall uncertainty in HDR Ir-192 dose delivery. Moreover, the results of the studies described in this thesis contribute significantly to the establishment of standardized numerical values to be used in HDR Ir-192 dosimetry calculations.

  12. Mutation process at low or high radiation doses

    International Nuclear Information System (INIS)

    Abrahamson, S.; Wisconsin Univ., Madison

    1976-01-01

    A concise review is given of the status of research on the genetic effects of low-level radiation in general. The term ''low dose'' is defined and current theories on low dose are set out. Problems and their solutions are discussed. (author)

  13. The revision of dose limits for exposure to ionizing radiation

    International Nuclear Information System (INIS)

    Hughes, D.

    1990-01-01

    The paper reviews the current dose limits for exposure to ionizing radiations and the risk factors on which they are based, and summarizes the revised risk factors and the draft proposals for new dose limits published by the International Commission on Radiological Protection. (author)

  14. Environmental policy. Ambient radioactivity levels and radiation doses in 1996

    International Nuclear Information System (INIS)

    1997-10-01

    The report is intended as information for the German Bundestag and Bundesrat as well as for the general population interested in issues of radiological protection. The information presented in the report shows that in 1996, the radiation dose to the population was low and amounted to an average of 4 millisievert (mSv), with 60% contributed by natural radiation sources, and 40% by artificial sources. The major natural source was the radioactive gas radon in buildings. Anthropogenic radiation exposure almost exclusively resulted from application of radioactive substances and ionizing radiation in the medical field, for diagnostic purposes. There still is a potential for reducing radiation doses due to these applications. In the reporting year, there were 340 000 persons occupationally exposed to ionizing radiation. Only 15% of these received a dose different from zero, the average dose was 1.8 mSv. The data show that the anthropogenic radiation exposure emanating from the uses of atomic energy or applications of ionizing radiation in technology is very low. (orig./CB) [de

  15. Biological effects of very low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Evseev, V.S.

    1987-01-01

    The paper deals with a qualitative microdosimetric analysis of a new radiobiological phenomenon (physiological reaction of the cell as a whole to very low doses of ionizing radiations). The analysis is aimed at identifying the type of the primary interaction of radiation with the cell and finding its place in the cell

  16. Epidemiology and effects on health of low ionizing radiation doses

    International Nuclear Information System (INIS)

    Rodriguez Artalejo, F.; Andres Manzano, B. de; Rel Calero, J. del

    1997-01-01

    This article describes the concept and aims of epidemiology, its methods and contribution to the knowledge of the effects of low ionizing radiation doses on health. The advantages of epidemiological studies for knowing the consequences of living near nuclear facilities and the effects of occupational exposure to radiations are also described. (Author) 43 refs

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

    African Journals Online (AJOL)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-03-01

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

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

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  20. Anticoagulation and high dose liver radiation. A preliminary report

    International Nuclear Information System (INIS)

    Lightdale, C.J.; Wasser, J.; Coleman, M.; Brower, M.; Tefft, M.; Pasmantier, M.

    1979-01-01

    Two groups of patients were observed for evidence of acute radiation hepatitis during high dose radiation to the liver. The first group of 18 patients with metastatic liver disease received an average of 4,050 rad to the whole liver. Half received anticoagulation with warfarin. One patient on anticoagulation developed evidence of acute radiation hepatitis while 2 patients did so without anticoagulation. Eleven patients with Hodgkin's disease received 4,000 rad to the left lobe of the liver during extended field radiation. Four of these 11 patients were anticoagulated to therapeutic range. Only one of the fully anticoagulated patients showed changes on liver scan consistent with radiation hepatitis whereas three did so without anticoagulation. No serious sequelae from anticoagulation occurred in either group. These preliminary data suggest that anticoagulation may be safely administered with high dose hepatic radiation and that further trials with anticoagulation are warranted

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

    Science.gov (United States)

    Almén, Anja; Båth, Magnus

    2016-06-01

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

  2. A conceptual framework for managing radiation dose to patients in diagnostic radiology using reference dose levels

    International Nuclear Information System (INIS)

    Almen, Anja; Baath, Magnus

    2016-01-01

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

  3. Radiation dose to the lens and cataract formation

    International Nuclear Information System (INIS)

    Henk, J.M.; Whitelocke, R.A.F.; Warrington, A.P.; Bessell, E.M.

    1993-01-01

    The purpose of this work was to determine the radiation tolerance of the lens of the eye and the incidence of radiation-induced lens changes in patients treated by fractionated supervoltage radiation therapy for orbital tumors. Forty patients treated for orbital lymphoma and pseudotumor with tumor doses of 20--40 Gy were studied. The lens was partly shielded using lead cylinders in most cases. The dose to the germinative zone of the lens was estimated by measurements in a tissue equivalent phantom using both film densitometry and thermoluminescent dosimetry. Opthalmological examination was performed at 6 monthly intervals after treatment. The lead shield was found to reduce the dose to the germinative zone of the lens to between 36--50% of the tumor dose for Cobalt beam therapy, and to between 11--18% for 5 MeV x-rays. Consequently, the lens doses were in the range 4.5--30 Gy in 10--20 fractions. Lens opacities first appeared from between 3 and 9 years after irradiation. Impairment of visual acuity ensued in 74% of the patients who developed lens opacities. The incidence of lens changes was strongly dose-related. None was seen after doses of 5 Gy or lower, whereas doses of 16.5 Gy or higher were all followed by lens opacities which impaired visual acuity. The largest number of patients received a maximum lens dose of 15 Gy; in this group the actuarial incidence of lens opacities at 8 years was 57% with visual impairment in 38%. The adult lens can tolerate a total dose of 5 Gy during a fractionated course of supervoltage radiation therapy without showing any changes. Doses of 16.5 Gy or higher will almost invariably lead to visual impairment. The dose which causes a 50% probability of visual impairment is approximately 15 Gy. 10 refs., 4 figs., 1 tab

  4. Some cosmic radiation dose measurements aboard flights connecting Zagreb Airport

    International Nuclear Information System (INIS)

    Vukovic, B.; Radolic, V.; Lisjak, I.; Vekic, B.; Poje, M.; Planinic, J.

    2008-01-01

    When primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard A320 and ATR40 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; the neutron dose was measured with the neutron dosimeter consisted of LR-115 track detector and boron foil BN-1 or 10 B converter. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed at the flights Zagreb-Paris-Buenos Aires and reversely, when one measured non-neutron cosmic radiation dose; for 26.7 h of flight, the MINI 6100 dosimeter gave an average dose rate of 2.3 μSv/h and the TLD dosimeter registered the dose equivalent of 75 μSv or the average dose rate of 2.7 μSv/h; the neutron dosimeter gave the dose rate of 2.4 μSv/h. In the same month, February 2005, a traveling to Japan (24-h-flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 μSv/h; the neutron dosimeter gave the dose rate of 2.5 μSv/h. Comparing dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level, we could conclude that the neutron component carried about 50% of the total dose, that was near other known data

  5. Some cosmic radiation dose measurements aboard flights connecting Zagreb Airport

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, B.; Radolic, V. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Lisjak, I. [Croatia Airlines, Zagreb (Croatia); Vekic, B. [Rudjer Boskovic Institute, Zagreb (Croatia); Poje, M. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia); Planinic, J. [Department of Physics, University of Osijek, Osijek, P.O. Box 125 (Croatia)], E-mail: planinic@ffos.hr

    2008-02-15

    When primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard A320 and ATR40 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; the neutron dose was measured with the neutron dosimeter consisted of LR-115 track detector and boron foil BN-1 or {sup 10}B converter. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed at the flights Zagreb-Paris-Buenos Aires and reversely, when one measured non-neutron cosmic radiation dose; for 26.7 h of flight, the MINI 6100 dosimeter gave an average dose rate of 2.3 {mu}Sv/h and the TLD dosimeter registered the dose equivalent of 75 {mu}Sv or the average dose rate of 2.7 {mu}Sv/h; the neutron dosimeter gave the dose rate of 2.4 {mu}Sv/h. In the same month, February 2005, a traveling to Japan (24-h-flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 {mu}Sv/h; the neutron dosimeter gave the dose rate of 2.5 {mu}Sv/h. Comparing dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level, we could conclude that the neutron component carried about 50% of the total dose, that was near other known data.

  6. Flight attendant radiation dose from solar particle events.

    Science.gov (United States)

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

    2014-08-01

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

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

    Science.gov (United States)

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

    2013-10-01

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

  8. Radiation Dose-Response Relationships and Risk Assessment

    International Nuclear Information System (INIS)

    Strom, Daniel J.

    2005-01-01

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

  9. Low-dose radiation-induced endothelial cell retraction

    International Nuclear Information System (INIS)

    Kantak, S.S.; Onoda, J.M.; Diglio, C.A.; Harper Hospital, Detroit, MI

    1993-01-01

    The data presented here are representative of a series of studies designed to characterize low-dose radiation effects on pulmonary microvascular endothelium. Data suggest that post-irradiation lung injuries (e.g. oedema) may be induced with only a single fraction of therapeutic radiation, and thus microscopic oedema may initiate prior to the lethal effects of radiation on the microvascular endothelium, and much earlier than would be suggested by the time course for clinically-detectable oedema. (author)

  10. Radiation dose and cancer risk to children undergoing skull radiography

    International Nuclear Information System (INIS)

    Mazonakis, Michael; Damilakis, John; Raissaki, Maria; Gourtsoyiannis, Nicholas

    2004-01-01

    Background: Limited data exist in the literature concerning the patient-effective dose from paediatric skull radiography. No information has been provided regarding organ doses, patient dose during PA skull projection, risk of cancer induction and dose to comforters, i.e. individuals supporting children during exposure. Objective: To estimate patient-effective dose, organ doses, lifetime cancer mortality risk to children and radiation dose to comforters associated with skull radiography. Materials and methods: Data were collected from 136 paediatric examinations, including AP, PA and lateral skull radiographs. Entrance-surface dose (ESD) and dose to comforters were measured using thermoluminescent dosimeters. Patients were divided into the following age groups: 0.5-2, 3-7, 8-12 and 13-18 years. The patient-effective dose and corresponding organ doses were calculated using data from the NRPB and Monte Carlo techniques. The risk for fatal cancer induction was assessed using appropriate risk coefficients. Results: For AP, PA and lateral skull radiography, effective dose ranges were 8.8-25.4, 8.2-27.3 and 8.4-22.7 μSv respectively, depending upon the age of the child. For each skull projection, the organs receiving doses above 10 μGy are presented. The number of fatal cancers was found to be less than or equal to 2 per 1 million children undergoing a skull radiograph. The mean radiation dose absorbed by the hands of comforters was 13.4 μGy. Conclusions: The current study provides detailed tabular and graphical data on ESD, effective dose, organ doses and lifetime cancer mortality risk to children associated with AP, PA and lateral skull projections at all patient ages. (orig.)

  11. Does fast-neutron radiotherapy merely reduce the radiation dose

    International Nuclear Information System (INIS)

    Ando, Koichi

    1984-01-01

    We examined whether fast-neutron radiotherapy is superior to low-LET radiotherpy by comparing the relationship between cell survival and tumor control probabilities after exposure of tumor-bearing (species) to the two modalities. Analysis based on TCD 50 assay and lung colony assay indicated that single dose of fast neutron achieved animal cures at higher survival rates than other radiation modalities including single and fractionated γ-ray doses, fractionated doses of fast neutron, and the mixed-beam scheme with a sequence of N-γ-γ-γ-N. We conclude that fast-neutron radiotherapy cured animal tumors with lower cell killing rates other radiation modalities. (author)

  12. Effects of target size on the comparison of photon and charged particle dose distributions

    International Nuclear Information System (INIS)

    Phillips, M.H.; Frankel, K.A.; Tjoa, T.; Lyman, J.T.; Fabrikant, J.I.; Levy, R.P.

    1989-12-01

    The work presented here is part of an ongoing project to quantify and evaluate the differences in the use of different radiation types and irradiation geometries in radiosurgery. We are examining dose distributions for photons using the ''Gamma Knife'' and the linear accelerator arc methods, as well as different species of charged particles from protons to neon ions. A number of different factors need to be studied to accurately compare the different modalities such as target size, shape and location, the irradiation geometry, and biological response. This presentation focuses on target size, which has a large effect on the dose distributions in normal tissue surrounding the lesion. This work concentrates on dose distributions found in radiosurgery, as opposed to those usually found in radiotherapy. 5 refs., 2 figs

  13. Therapeutic effects of low radiation doses

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-01-01

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

  14. Monitoring of radiation exposure and registration of doses

    International Nuclear Information System (INIS)

    1993-01-01

    The Section 32 of the Finnish Radiation Act (592/91) defines the requirements to be applied to the monitoring of the radiation exposure and working conditions in Finland. The concepts relevant to the monitoring and guidelines for determining the necessity of the monitoring as well as its organizing are given in the guide. Instructions for reporting doses to the Dose Register of the Finnish Centre for Radiation and Nuclear Safety (STUK) are given, also procedures for situations leading to exceptional exposures are described. (9 refs.)

  15. CONDOS-II, Radiation Dose from Consumer Product Distribution Chain

    International Nuclear Information System (INIS)

    1984-01-01

    1 - Description of problem or function: This code was developed under sponsorship of the Nuclear Regulatory Commission to serve as a tool for assessing radiation doses that may be associated with consumer products that contain radionuclides. The code calculates radiation dose equivalents resulting from user-supplied scenarios of exposures to radionuclides contained in or released from sources that contain radionuclides. Dose equivalents may be calculated to total body, skin surface, skeletal bone, testes, ovaries, liver, kidneys, lungs, and maximally exposed segments of the gastrointestinal tract from exposures via (1) direct, external irradiation by photons (including Bremsstrahlung) emitted from the source, (2) external irradiation by photons during immersion in air containing photon-emitting radionuclides that have escaped from the source, (3) internal exposures by all radiations emitted by inhaled radionuclides that have escaped from the source, and (4) internal exposures by all radiations emitted by ingested radionuclides that have escaped from the source. 2 - Method of solution: Organ dose equivalents are approximated in two ways, depending on the exposure type. For external exposures, energy specific organ-to-skin-surface dose conversion ratios are used to approximate dose equivalents to specific organs from doses calculated to a point on the skin surface. The organ-to-skin ratios are incorporated in organ- and nuclide-specific dose rate factors, which are used to approximate doses during immersion in contaminated air. For internal exposures, 50 year dose equivalents are calculated using organ- and nuclide-specific, 50 year dose conversion factors. Doses from direct, external exposures are calculated using the energy-specific dose conversion ratios, user supplied exposure conditions, and photon flux approximations for eleven source geometries. Available source geometries include: point, shielded and unshielded; line, shielded and unshielded; disk, shielded

  16. Plants as warning signal for exposure to low dose radiation

    International Nuclear Information System (INIS)

    Rusli Ibrahim; Norhafiz Talib

    2012-01-01

    The stamen-hair system of Tradescantia for flower colour has proven to be one of the most suitable materials to study the frequency of mutations induced by low doses of various ionizing radiations and chemical mutagens. The system has also been used successfully for detecting mutagenic synergisms among chemical mutagens and ionizing radiations as well as for studying the variations of spontaneous mutation frequency. In this study of radiobiology, the main objective is to observe somatic mutation (occurrence of pink cells from blue cells) induced on stamen hairs of five Tradescantia sp. available in Malaysia after exposure to low doses of chronic gamma irradiation using Gamma Green House. Pink cells appeared only on Tradescantia Pallida Purpurea stamen hairs after 13 days of exposure to irradiation with different doses of gamma rays. The highest number of stamens with pink cells was recorded from flowers irradiated with the highest dose of 6.37 Gy with 0.07 Gy/ h of dose rate. The lowest number of stamens with pink cells was recorded with an average of 0.57, irradiated with the lowest dose of 0.91 Gy with 0.01 Gy/ h of dose rate. There were no pink cells observed on Tradescantia Spathaceae Discolor after exposure to different doses of gamma rays. Similar negative results were observed for the control experiments. The principal cells in this assay are the mitotic stamen hair cells developing in the young flower buds. After exposure to radiation, the heterozygous dominant blue character of the stamen hair cell is prevented, resulting in the appearance of the recessive pink color. Furthermore, no pink cell appears on all species of Tradescantia spathaceae after irradiated with different doses of gamma rays. The sensitivity of the Tradescantia has been used widely and has demonstrated the relation between radiation dose and frequency of mutation observed at low doses which can contribute to the effects of low doses and their consequences for human health. This system

  17. Assessment of patient radiation doses during routine diagnostic radiography examinations

    International Nuclear Information System (INIS)

    Adam, Asim Karam Aldden Adam

    2015-11-01

    Medical applications of radiation represent the largest source of exposure to general population. Accounting for 3.0 mSv against an estimated 2.4 mSv from a natural back ground in United States. The association of ionizing radiation an cancer risk is assumed to be continuos and graded over the entire range of exposure, The objective of this study is to evaluate the patient radiation doses in radiology departments in Khartoum state. A total of 840 patients ? during two in the following hospitals Khartoum Teaching Hospital (260 patients), Fedail specialized hospital ( 261 patients). National Ribat University hospital ( 189 patients) and Engaz hospital (130 patients). Patient doses were measured for 9 procedures. The Entrance surface Air Kerma (ESAK) was quantified using x-ray unit output by Unifiers xi dose rate meter( Un fore inc. Billdal. Sweden) and patient exposure parameters. The mean patient age. Weight and Body Mass index (BMI) were 42.6 year 58/4 kg and 212 kg/m respectively. The mean patient doses, kv and MAS and E.q was 0.35 mGy per procedures 59.9 volt 19.8 Ampere per second 0.32 Sv . Patient doses were comparable with previous studies. Patient radiation doses showed considerable difference between hospitals due to x- ray systems exposure settings and patient weight. Patient are exposed to unnecessary radiation.(Author)

  18. Dose received by radiation workers in Australia, 1991

    International Nuclear Information System (INIS)

    Morris, N.D.

    1994-07-01

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

  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. Dose received by radiation workers in Australia, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Morris, N D

    1994-07-01

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

  1. Evaluation of radiation doses delivered in different chest CT protocols

    International Nuclear Information System (INIS)

    Gorycki, Tomasz; Lasek, Iwona; Kamiński, Kamil; Studniarek, Michał

    2014-01-01

    There are differences in the reference diagnostic levels for the computed tomography (CT) of the chest as cited in different literature sources. The doses are expressed either in weighted CT dose index (CTDI VOL ) used to express the dose per slice, dose-length product (DLP), and effective dose (E). The purpose of this study was to assess the radiation dose used in Low Dose Computer Tomography (LDCT) of the chest in comparison with routine chest CT examinations as well as to compare doses delivered in low dose chest CT with chest X-ray doses. CTDI VOL and DLP doses were taken to analysis from routine CT chest examinations (64 MDCT TK LIGHT SPEED GE Medical System) performed in 202 adult patients with FBP reconstruction: 51 low dose, 106 helical, 20 angio CT, and 25 high resolution CT protocols, as well as 19 helical protocols with iterative ASIR reconstruction. The analysis of chest X-ray doses was made on the basis of reports from 44 examinations. Mean values of CTDI VOL and DLP were, respectively: 2.1 mGy and 85.1 mGy·cm, for low dose, 9.7 mGy and 392.3 mGy·cm for helical, 18.2 mGy and 813.9 mGy·cm for angio CT, 2.3 mGy and 64.4 mGy·cm for high resolution CT, 8.9 mGy. and 317.6 mGy·cm for helical ASIR protocols. Significantly lower CTDI VOL and DLP values were observed for low dose and high resolution CT versus the remaining CT protocols; doses delivered in CT ASIR protocols were also lower (80–81%). The ratio between medial doses in low dose CT and chest X-ray was 11.56. Radiation dose in extended chest LDCT with parameters allowing for identification of mediastinal structures and adrenal glands is still much lower than that in standard CT protocols. Effective doses predicted for LDCT may exceed those used in chest X-ray examinations by a factor of 4 to 12, depending on LDCT scan parameters. Our results, as well as results from other authors, suggest a possibility of reducing the dose by means of iterative reconstruction. Efforts towards further dose

  2. Gamma radiation dose from radionuclides in Kong Kong soil

    International Nuclear Information System (INIS)

    Leung, K.C.

    1990-01-01

    Calculations have been made of the γ dose rate at one metre above ground from the results of measurements of radionuclide concentrations in soil at various locations in Hong Kong and prior to the Chernobyl accident. The average dose rate is found to be 0.076 μGy h -1 , or 0.67 mGy year -1 . The contribution from fallout nuclides to the annual dose is shown to be small, at about 0.4% of the total. The calculated dose rate in this work is about 80% higher than the world average given by the United Nations Scientific Committee on the Effects of Atomic Radiation, in Ionizing Radiation: Sources and Biological Effects, Annex B (Exposure to natural radiation sources). A United Nations Publication, 1982. (author)

  3. Status of eye lens radiation dose monitoring in European hospitals

    International Nuclear Information System (INIS)

    Carinou, Eleftheria; Ginjaume, Merce; O’Connor, Una; Kopec, Renata; Sans Merce, Marta

    2014-01-01

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. (paper)

  4. Some human activities to decrease public radiation dose

    International Nuclear Information System (INIS)

    Pan Ziqiang; Guo Minqiang

    1994-01-01

    The necessity of studying the variations in radiation levels from the balance viewpoint is discussed. Some human activities may increase, while others may decrease, radiation dose to population. In 1988, China's investigation showed that travel by air caused a raise of population collective dose by 3.6 x 10 1 man·Sv, while travel by ship, train and vehicle lead to a drop of 5.36 x 10 2 man·Sv, and that dwellings of coal cinder brick decreased collective dose by 3.5 x 10 3 man·Sv, while buildings of reinforced concrete structure increased collective dose by 3.7 x 10 3 man·Sv. It is inadequate to only study those activities which may increase radiation levels

  5. Inhomogeneous target-dose distributions: a dimension more for optimization?

    International Nuclear Information System (INIS)

    Gersem, Werner R.T. de; Derycke, Sylvie; Colle, Christophe O.; Wagter, Carlos de; Neve, Wilfried J. de

    1999-01-01

    Purpose: To evaluate if the use of inhomogeneous target-dose distributions, obtained by 3D conformal radiotherapy plans with or without beam intensity modulation, offers the possibility to decrease indices of toxicity to normal tissues and/or increase indices of tumor control stage III non-small cell lung cancer (NSCLC). Methods and Materials: Ten patients with stage III NSCLC were planned using a conventional 3D technique and a technique involving noncoplanar beam intensity modulation (BIM). Two planning target volumes (PTVs) were defined: PTV1 included macroscopic tumor volume and PTV2 included macroscopic and microscopic tumor volume. Virtual simulation defined the beam shapes and incidences as well as the wedge orientations (3D) and segment outlines (BIM). Weights of wedged beams, unwedged beams, and segments were determined by optimization using an objective function with a biological and a physical component. The biological component included tumor control probability (TCP) for PTV1 (TCP1), PTV2 (TCP2), and normal tissue complication probability (NTCP) for lung, spinal cord, and heart. The physical component included the maximum and minimum dose as well as the standard deviation of the dose at PTV1. The most inhomogeneous target-dose distributions were obtained by using only the biological component of the objective function (biological optimization). By enabling the physical component in addition to the biological component, PTV1 inhomogeneity was reduced (biophysical optimization). As indices for toxicity to normal tissues, NTCP-values as well as maximum doses or dose levels to relevant fractions of the organ's volume were used. As indices for tumor control, TCP-values as well as minimum doses to the PTVs were used. Results: When optimization was performed with the biophysical as compared to the biological objective function, the PTV1 inhomogeneity decreased from 13 (8-23)% to 4 (2-9)% for the 3D-(p = 0.00009) and from 44 (33-56)% to 20 (9-34)% for the BIM

  6. Visualization of radiation dose big data acquired by monitoring posts

    International Nuclear Information System (INIS)

    Hashimoto, Takeyuki; Jumonji, Hiromichi

    2014-01-01

    Currently, in Fukushima Prefecture, 3625 radiation dose monitoring posts is available, and the radiation data is acquired every 10 minutes. However, an effective visualization of such an enormous amount of data has not been sufficiently performed. In this study, pull out the meaningful information from the big data, to achieve an effective visualization. By comparing the physical attenuation with the radiation dose changes, we can predict the trend of environment attenuation. We visualize the influence of the environment by plotting the results to the map. As a result, the difference in the increase or decrease depending on the location appeared. Under the influence of snow cover, a phenomenon that radiation dose is reduced in winter were also seen. We considered that these results will be effective for the policies of decontamination and the estimation of the amount of snow as water resources. (author)

  7. Mathematical models for calculating radiation dose to the fetus

    International Nuclear Information System (INIS)

    Watson, E.E.

    1992-01-01

    Estimates of radiation dose from radionuclides inside the body are calculated on the basis of energy deposition in mathematical models representing the organs and tissues of the human body. Complex models may be used with radiation transport codes to calculate the fraction of emitted energy that is absorbed in a target tissue even at a distance from the source. Other models may be simple geometric shapes for which absorbed fractions of energy have already been calculated. Models of Reference Man, the 15-year-old (Reference Woman), the 10-year-old, the five-year-old, the one-year-old, and the newborn have been developed and used for calculating specific absorbed fractions (absorbed fractions of energy per unit mass) for several different photon energies and many different source-target combinations. The Reference woman model is adequate for calculating energy deposition in the uterus during the first few weeks of pregnancy. During the course of pregnancy, the embryo/fetus increases rapidly in size and thus requires several models for calculating absorbed fractions. In addition, the increases in size and changes in shape of the uterus and fetus result in the repositioning of the maternal organs and in different geometric relationships among the organs and the fetus. This is especially true of the excretory organs such as the urinary bladder and the various sections of the gastrointestinal tract. Several models have been developed for calculating absorbed fractions of energy in the fetus, including models of the uterus and fetus for each month of pregnancy and complete models of the pregnant woman at the end of each trimester. In this paper, the available models and the appropriate use of each will be discussed. (Author) 19 refs., 7 figs

  8. Dose Rate of Environmental Gamma Radiation in Java Island

    International Nuclear Information System (INIS)

    Gatot Suhariyono; Buchori; Dadong Iskandar

    2007-01-01

    The dose rate Monitoring of environmental gamma radiation at some locations in Java Island in the year 2005 / 2006 has been carried out. The dose rate measurement of gamma radiation is carried out by using the peripheral of Portable Gamma of Ray Spectrometer with detector of NaI(Tl), Merck Exploranium, Model GR-130- MINISPEC, while to determine its geographic position is used by the GPS (Global Positioning System), made in German corporation of GPS III Plus type. The division of measurement region was conducted by dividing Java Island become 66 parts with same distance, except in Jepara area that will built PLTN (Nuclear Energy Power), distance between measurement points is more closed. The results of dose rate measurement are in 66 locations in Java Island the range of (19.24 ± 4.05) nSv/hour until (150.78 ± 12.26) nSv/hour with mean (51.93 ± 36.53) nSv/h. The lowest dose rate was in location of Garut, while highest dose rate was in Ujung Lemah Abang, Jepara location. The data can be used for base line data of dose rate of environmental gamma radiation in Indonesia, specially in Java Island. The mean level of gamma radiation in Java monitoring area (0.46 mSv / year) was still lower than worldwide average effective dose rate of terrestrial gamma rays 0.5 mSv / year (report of UNSCEAR, 2000). (author)

  9. Circuit arrangement for indicating radiation dose rates

    International Nuclear Information System (INIS)

    Virag, Ernoe; Nyari, Istvan; Simon, Jozsef; Styevko, Mihaly; Krampe, Geza.

    1981-01-01

    The invention presents a dosemeter electronic circuit arrangement indicating hazardous dose rate threshold. If the treshold is reached or exceeded, well distinguished sound and light alarm is turned on immidiately. Moreover, certain critical levels can also be indicated by making the intermittent singalling continuous. (A.L.)

  10. Online radiation dose measurement system for ATLAS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mandic, I.; Cindro, V.; Dolenc, I.; Gorisek, A.; Kramberger, G. [Jozef Stefan Institute, Jamova 39, Ljubljana (Slovenia); Mikuz, M. [Jozef Stefan Institute, Jamova 39, Ljubljana (Slovenia); Faculty of Mathematics and Physics, University of Ljubljana (Slovenia); Bronner, J.; Hartet, J. [Physikalisches Institut, Universitat Freiburg, Hermann-Herder-Str. 3, Freiburg (Germany); Franz, S. [CERN, Geneva (Switzerland)

    2009-07-01

    In experiments at Large Hadron Collider, detectors and electronics will be exposed to high fluxes of photons, charged particles and neutrons. Damage caused by the radiation will influence performance of detectors. It will therefore be important to continuously monitor the radiation dose in order to follow the level of degradation of detectors and electronics and to correctly predict future radiation damage. A system for online radiation monitoring using semiconductor radiation sensors at large number of locations has been installed in the ATLAS experiment. Ionizing dose in SiO{sub 2} will be measured with RadFETs, displacement damage in silicon in units of 1-MeV(Si) equivalent neutron fluence with p-i-n diodes. At 14 monitoring locations where highest radiation levels are expected the fluence of thermal neutrons will be measured from current gain degradation in dedicated bipolar transistors. The design of the system and tests of its performance in mixed radiation field is described in this paper. First results from this test campaign confirm that doses can be measured with sufficient sensitivity (mGy for total ionizing dose measurements, 10{sup 9} n/cm{sup 2} for NIEL (non-ionizing energy loss) measurements, 10{sup 12} n/cm{sup 2} for thermal neutrons) and accuracy (about 20%) for usage in the ATLAS detector

  11. Online radiation dose measurement system for ATLAS experiment

    International Nuclear Information System (INIS)

    Mandic, I.; Cindro, V.; Dolenc, I.; Gorisek, A.; Kramberger, G.; Mikuz, M.; Bronner, J.; Hartet, J.; Franz, S.

    2009-01-01

    In experiments at Large Hadron Collider, detectors and electronics will be exposed to high fluxes of photons, charged particles and neutrons. Damage caused by the radiation will influence performance of detectors. It will therefore be important to continuously monitor the radiation dose in order to follow the level of degradation of detectors and electronics and to correctly predict future radiation damage. A system for online radiation monitoring using semiconductor radiation sensors at large number of locations has been installed in the ATLAS experiment. Ionizing dose in SiO 2 will be measured with RadFETs, displacement damage in silicon in units of 1-MeV(Si) equivalent neutron fluence with p-i-n diodes. At 14 monitoring locations where highest radiation levels are expected the fluence of thermal neutrons will be measured from current gain degradation in dedicated bipolar transistors. The design of the system and tests of its performance in mixed radiation field is described in this paper. First results from this test campaign confirm that doses can be measured with sufficient sensitivity (mGy for total ionizing dose measurements, 10 9 n/cm 2 for NIEL (non-ionizing energy loss) measurements, 10 12 n/cm 2 for thermal neutrons) and accuracy (about 20%) for usage in the ATLAS detector

  12. 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

  13. Survey of environmental radiation dose rates in Tokushima prefecture

    International Nuclear Information System (INIS)

    Sakama, Minoru; Imura, Hiroyoshi; Akou, Natsuki; Takeuchi, Emi; Morihiro, Yukinori

    2004-01-01

    Survey of environmental radiation dose rates in Tokushima prefecture has been carried out using a portable NaI (Tl) scintillation survey meter and a CsI(Tl) pocket type one. To our knowledge, previous several surveys in Tokushima, for example by Abe et al. (1982) and Yoshino et al. (1991), have remained to report the environmental radiation dose rates merely about the major cities, that is Tokushima City and others along the Pacific. Up to now, there have been few efforts to survey the environmental radiation dose rates about mountain valleys in Tokushima. In this work, it is remarkable that we have for the first time made surveys of environmental radiation dose rates on the 6 routes across the Sanuki mountains and inside the pier of Onaruto Bridge, 'Naruto Uzu-no-michi', in the northern area of Tokushima. In the course of present surveys, the maximum value of the environmental radiation dose rates was 0.117±0.020 μGy/h at Higetouge in Sanuki City, and then it was found that the radiation dose rates across the Sanuki mountains tend to increase slightly with approaching Kagawa area from Tokushima one. Considering geological formation around the northern side of Sanuki mountains, there are mainly geological layers of granodiorite containing in the substantial amount of naturally occurring radionuclides, 40 K, U-series, and Th-series, than other geological rocks and it was found that the terrestrial gamma-rays have effect on the environmental radiation dose rates according to the geological formation. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Kleiman, Norman Jay [Columbia University

    2013-11-30

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

  15. Radiation doses to children with shunt-treated hydrocephalus

    Energy Technology Data Exchange (ETDEWEB)

    Holmedal, Lise J. [Helse Fonna, Department of Radiology, Stord Hospital, Stord (Norway); Friberg, Eva G.; Boerretzen, Ingelin; Olerud, Hilde [The Norwegian Radiation Protection Authority, Oesteraas (Norway); Laegreid, Liv [Haukeland University Hospital, Department of Paediatrics, Bergen (Norway); Rosendahl, Karen [University of Bergen, Department of Surgical Sciences, Radiology Section, Bergen (Norway); Great Ormond Street Hospital for Children, Department of Diagnostic Radiology, London (United Kingdom)

    2007-12-15

    Children with shunt-treated hydrocephalus are still followed routinely with frequent head CT scans. To estimate the effective dose, brain and lens doses from these examinations during childhood, and to assess dose variation per examination. All children born between 1983 and 1995 and treated for hydrocephalus between 1983 and 2002 were included. We retrospectively registered the number of examinations and the applied scan parameters. The effective dose was calculated using mean conversion factors from the CT dose index measured free in air, while doses to the lens and brain were estimated using tabulated CT dose index values measured in a head phantom. A total of 687 CT examinations were performed in 67 children. The mean effective dose, lens dose and brain dose to children over 6 months of age were 1.2 mSv, 52 mGy and 33 mGy, respectively, and the corresponding doses to younger children were 3.2 mSv, 60 mGy and 48 mGy. The effective dose per CT examination varied by a factor of 64. None of the children was exposed to doses known to cause deterministic effects. However, since the threshold for radiation-induced damage is not known with certainty, alternative modalities such as US and MRI should be used whenever possible. (orig.)

  16. Occupational radiation doses in Portugal from 1994 to 1998

    International Nuclear Information System (INIS)

    Alves, J.G.; Martins, M.B.; Amaral, E.M.

    2000-01-01

    This work reports on the occupational radiation doses for external radiation received in 1994-1998 by the radiation workers monitored by the Radiological Protection and Nuclear Safety Department (DPRSN) in Portugal. Individual monitoring for external radiation is carried out in Portugal by DPRSN since the 60s, and the workers are monitored on a monthly or quarterly bases. In 1995 DPRSN monitored approximately 8000 people and was the only laboratory carrying out this sort of activity in Portugal. In 1998 the number of monitored people increased to nearly 8500 from 860 facilities, which leads us to state that the results shown in this work are well representative of the universe of radiation workers in Portugal. Until 1996, the dose measurement procedure was based only on film dosimetry and the results reported for the 1994-1995 period were obtained with this methodology. Since 1996, thermoluminescent dosimetry (TLD) was gradually introduced and since then an effort has been made to transfer the monitored workers from film to TLD. In 1998, both film and TLD dosimetry systems were running simultaneously, with average numbers of 4500 workers monitored with film dosimetry, while 4000 were monitored with TLD. The data presented from 1996 to 1998 were obtained with both methodologies. This work reports the annual mean effective doses received from external radiation, for the monitored and exposed workers in the different fields of activity, namely, industry, research laboratories, health and mining. The distribution of the annual effective dose by dose intervals is also reported. The collective annual dose by field of activity is estimated and the contribution to the total annual collective dose is determined. The collective dose estimates for the period 1994 to 1998 demonstrated that the health sector is the most representative exposed group in Portugal. (author)

  17. Emissions and doses from sources of ionising radiation in the Netherlands: radiation policy monitoring

    International Nuclear Information System (INIS)

    Eleveld, H.; Pruppers, M.

    2002-01-01

    In 1997 the Ministry of Housing, Spatial Planning and the Environment requested RIVM to develop an information system for policy monitoring. One of the motives was that the European Union requires that the competent authorities of each member state ensure that dose estimates due to practices involving exposure to ionising radiation are made as realistic as possible for the population as a whole and for reference groups in all places where such groups may occur. Emissions of radionuclides and radiation to the environment can be classified as follows: (1) emissions to the atmosphere, (2) emissions to the aquatic system and (3) emission of external radiation from radioactive materials and equipment that produces ionising radiation. Released radioactivity is dispersed via exposure pathways, such as the atmosphere, deposition on the ground and farmland products, drinking water, fish products, etc. This leads to radiation doses due to inhalation, ingestion and exposure to external radiation. To assess the possible radiation doses different kinds of models are applied, varying from simple multiplications with dispersion coefficients, transfer coefficients and dose conversion coefficients to complex dispersion models. In this paper an overview is given of the human-induced radiation doses in the Netherlands. Also, trends in and the effect of policy on the radiation dose of members of the public are investigated. This paper is based on an RIVM report published recently. A geographical distribution of radiation risks due to routine releases for a typical year in the Netherlands was published earlier

  18. A unique experiment. Measurement of radiation doses at Vinca

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-07-15

    For the first time in the history of the peaceful applications of atomic energy, an experiment was conducted to determine the exact levels of radiation exposure resulting from a reactor incident. The experiment was made at Vinca, Yugoslavia, wherein October 1958 six persons had been subjected to high doses of neutron and gamma radiation during a brief uncontrolled run of a zero-power reactor. One of them died but the other five were successfully treated at the Curie Hospital in Paris. In the case of four of them, the treatment involved the grafting of healthy bone marrow to counteract the effects of radiation on blood-forming tissues. It was recognized that if the effects produced on the irradiated persons could be related to the exact doses of radiation they had received, it would be possible to gain immensely valuable knowledge about the biological consequences of acute and high level radiation exposure on a quantitative basis. It was suggested to the Yugoslav authorities that a dosimetry experiment be conducted at Vinca. The most accurate modern techniques of dosimetry developed at the Oak Ridge National Laboratory were employed during the experiment. Simultaneous measurements of the neutron and gamma doses were made at points where the people had been located. At these points the effects of the radiation on the salt solution in the phantoms were studied. In particular, the energy distribution of the radiation was investigated.It was the ratio between the various components of the radiation that was of special interest in these measurements because this ratio itself would help in determining the exact doses. The dose of one of the components, viz. slow neutrons, had already been determined during the treatment of the patients. If the ratio of the components could be ascertained, the doses of the fast neutrons and gamma rays could also be established because the ratio would not be affected by the power level at which the reactor was operated

  19. Occupational radiation doses among diagnostic radiation workers in South Korea, 1996-2006

    International Nuclear Information System (INIS)

    Lee, W. J.; Cha, E. S.; Ha, M.; Jin, Y. W.; Hwang, S. S.; Kong, K. A.; Lee, S. W.; Lee, H. K.; Lee, K. Y.; Kim, H. J.

    2009-01-01

    This study details the distribution and trends of doses of occupational radiation among diagnostic radiation workers by using the national dose registry between 1996 and 2006 by the Korea Food and Drug Administration. Dose measurements were collected quarterly by the use of thermoluminescent dosemeter personal monitors. A total of 61 732 workers were monitored, including 18 376 radiologic technologists (30%), 13 762 physicians (22%), 9858 dentists (16%) and 6114 dental hygienists (9.9%). The average annual effective doses of all monitored workers decreased from 1.75 to 0.80 mSv over the study period. Among all diagnostic radiation workers, radiologic technologists received both the highest effective and collective doses. Male radiologic technologists aged 30-49 y composed the majority of workers receiving more than 5 mSv in a quarter. More intensive monitoring of occupational radiation exposure and investigation into its health effects on diagnostic radiation workers are required in South Korea. (authors)

  20. Suicide genes or p53 gene and p53 target genes as targets for cancer gene therapy by ionizing radiation

    International Nuclear Information System (INIS)

    Liu Bing; Chinese Academy of Sciences, Beijing; Zhang Hong

    2005-01-01

    Radiotherapy has some disadvantages due to the severe side-effect on the normal tissues at a curative dose of ionizing radiation (IR). Similarly, as a new developing approach, gene therapy also has some disadvantages, such as lack of specificity for tumors, limited expression of therapeutic gene, potential biological risk. To certain extent, above problems would be solved by the suicide genes or p53 gene and its target genes therapies targeted by ionizing radiation. This strategy not only makes up the disadvantage from radiotherapy or gene therapy alone, but also promotes success rate on the base of lower dose. By present, there have been several vectors measuring up to be reaching clinical trials. This review focused on the development of the cancer gene therapy through suicide genes or p53 and its target genes mediated by IR. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    Strom, Daniel J.

    2008-04-14

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

  2. 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

  3. Management of pediatric radiation dose using Philips fluoroscopy systems DoseWise: perfect image, perfect sense

    International Nuclear Information System (INIS)

    Stueve, Dick

    2006-01-01

    Although image quality (IQ) is the ultimate goal for accurate diagnosis and treatment, minimizing radiation dose is equally important. This is especially true when pediatric patients are examined, because their sensitivity to radiation-induced cancer is two to three times greater than that of adults. DoseWise is an ALARA-based philosophy within Philips Medical Systems that is active at every level of product design. It encompasses a set of techniques, programs and practices that ensures optimal IQ while protecting people in the X-ray environments. DoseWise methods include management of the X-ray beam, less radiation-on time and more dose information for the operator. Smart beam management provides automatic customization of the X-ray beam spectrum, shape, and pulse frequency. The Philips-patented grid-controlled fluoroscopy (GCF) provides grid switching of the X-ray beam in the X-ray tube instead of the traditional generator switching method. In the examination of pediatric patients, DoseWise technology has been scientifically documented to reduce radiation dose to <10% of the dose of traditional continuous fluoroscopy systems. The result is improved IQ at a significantly lower effective dose, which contributes to the safety of patients and staff. (orig.)

  4. Radiation doses from dental radiography at private practioneers

    Energy Technology Data Exchange (ETDEWEB)

    Hylthen, J A

    1975-10-01

    This investigation was made in January 1975 together with a seminar group from the faculty of odontology in Stockholm. Every four private practising dentists in Stockholm and its environs were selected by haphazard to get an enquiry equipment etc. Every forty private practising dentists were then selected by haphazard to get a visit. 32 x-ray plants were investigated. The radiation doses showed a great spreading. The mean value of the radiation doses to the irradiated organs had been reduced about 5 times compared to a similar investigation, which was made in 1960. The use of long metal tubes and high-speed film gave the lowest dose values, while a short cone of bakelite and a low-speed film gave the highest dose values. Fluctuations in the dose values seemed also to depend on the technique. The reasons for this may be variations in the settings of the instruments and in the dark room technique.

  5. Radiation Target Area Sample Environmental Chamber (RTASEC), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Payload Systems Inc. proposes the Radiation Target Area Sample Environmental Chamber (RTASEC) as an innovative approach enabling radiobiologists to investigate the...

  6. The 3D Radiation Dose Analysis For Satellite

    Science.gov (United States)

    Cai, Zhenbo; Lin, Guocheng; Chen, Guozhen; Liu, Xia

    2002-01-01

    the earth. These particles come from the Van Allen Belt, Solar Cosmic Ray and Galaxy Cosmic Ray. They have different energy and flux, varying with time and space, and correlating with solar activity tightly. These particles interact with electrical components and materials used on satellites, producing various space radiation effects, which will damage satellite to some extent, or even affect its safety. orbit. Space energy particles inject into components and materials used on satellites, and generate radiation dose by depositing partial or entire energy in them through ionization, which causes their characteristic degradation or even failure. As a consequence, the analysis and protection for radiation dose has been paid more attention during satellite design and manufacture. Designers of satellites need to analyze accurately the space radiation dose while satellites are on orbit, and use the results as the basis for radiation protection designs and ground experiments for satellites. can be calculated, using the model of the trapped proton and the trapped electron in the Van Allen Belt (AE8 and AP8). This is the 1D radiation dose analysis for satellites. Obviously, the mass shielding from the outside space to the computed point in all directions is regarded as a simple sphere shell. The actual structure of satellites, however, is very complex. When energy particles are injecting into a given equipment inside satellite from outside space, they will travel across satellite structure, other equipment, the shell of the given equipment, and so on, which depends greatly on actual layout of satellite. This complex radiation shielding has two characteristics. One is that the shielding masses for the computed point are different in different injecting directions. The other is that for different computed points, the shielding conditions vary in all space directions. Therefore, it is very difficult to tell the differences described above using the 1D radiation analysis, and

  7. SU-E-T-278: Dose Conformity Index for the Target in a Multitarget Environment

    Energy Technology Data Exchange (ETDEWEB)

    Harikrishnaperumal, Sudahar [Apollo Speciality Hospital, Chennai, Tamil Nadu (India)

    2015-06-15

    Purpose: The existing conformity index formulations are failing when multiple targets present outside the target of interest with same or different dose prescriptions. In the present study a novel methodology is introduced to solve this issue. Methods: The conformity index used by Nakamura et al (Int J Radiat Oncol Biol Phys 2001; 51(5):1313–1319) is taken as the base for this methodology. In this proposal, the prescription isodose volume (PIV) which normally includes the normal tissue and other target regions is restricted as PIV in annular regions of different thickness around the target of interest. The graphical line plotted between the thickness of annular region and the corresponding conformity index, will increase in the beginning and will reach a flat region, then it will increase again. The second increase in the conformity index depends basically on the distance between the targets, dose prescriptions, and size of the targets. The conformity index in the flat region should be the conformity index of the target of interest. This methodology was validated on dual target environment on a skull phantom in Multiplan planning system (Accuray Inc. Sunnyvale, USA) Results: When the surrounding target’s (sphere) size is changed from 1.5cm to 6cm diameter, the conformity index of the target of interest (3cm diameter) changed from 1.09 to 1.25. When the distance between the targets changed from 7.5cm to 2.5cm, the conformity index changed from 1.10 to 1.17. Similarly, when the prescribed dose changed from 25Gy to 50Gy the conformity index changed from 1.09 to 1.42. These values were above 2.0 when Nakamura et al formula was used. Conclusion: The proposed conformity index methodology eliminates the influence of surrounding targets to a greater extend. However, the limitations of this method should be studied further. Application of this method in clinical situations is the future scope.

  8. Natural external radiation level and population dose in Hunan province

    International Nuclear Information System (INIS)

    1985-01-01

    A survey of the natural external radiation level in Hunan Province is reported. The measurements were performed with FD-71 scintillation radiometers. On the basis of measurements at about 1,600 locations, the contribution from cosmic radiation is found to be 3.0 x 10 -8 Gy.h -1 , and the average absorbed dose rates in air from terrestrial γ-radiation for outdoors, indoors and roads are determined to be 9.2, 13.1 and 9.0 x 10 -8 Gy.h -1 , respectively. The γ-radiation indoors is markedly higher than that outdoors by a factor of 1.42. The lowest γ-radiation level is found in the sedimentary plain around Donting Lake, while the highest absorbed dose rates in air from terrestrial radiation are observed in some areas with exposed granites. The indoor γ-radiation in brick houses is markedly higher than that in wooden houses. Tarred roads have evidently lower radiation level than sand-gravel roads or concrete roads. The annual effective dose equivalents to the population from cosmic and terrestrial sources are 0.256 and 0.756 mSv, respectively, with a total value of 1.012 mSv

  9. Intensity-modulated radiation therapy for nasopharyngeal carcinoma parotid sparing with euivalent uiform dose optimization

    International Nuclear Information System (INIS)

    Yue Weiyou; Dai Jianrong; Gao Li

    2006-01-01

    Objective: The aim of this study was to evaluate the role of an euivalent uiform dose (EUD) based optimization algorithm in sparing the parotids of patients with nasopharyngeal carcinoma (NPC) when they are treated with intensity-modulated radiation therapy (IMRT). Methods: 12 patients were randomly selected from the NPC patients who received IMRT treatments. For these patients, the treatment plans were designed with physical optimization constraints (dose/dose-volume constraints). Based on these plans, new plans were designed through replacing the physical constraints with maximum EUD for parotids, while keeping the physical objectives for targets and other organs at risk(OARs) unchanged. Comparison was then made between the new plan, which had EUD constraints to parotids, and the former for each individual patient. Results: While maintaining the dose to the targets and the other OARs un- changed, optimization with EUD constraints to parotids decreased the mean dose and V 30 of parotids significantly, simultaneously, the dose of target volume and other organs at risk keep stable, the values of probability were less than 0.05 by T-test. Conclusions: The doses to parotids can be reduced through optimization with EUD constraints. This finding is quite helpful to reduce the occurrence rate of parotid complications, and to provide spaces for escalating target dose. (authors)

  10. Radiation doses and radiation risk in foreign nuclear objects

    International Nuclear Information System (INIS)

    Tvehlov, Yu.

    2001-01-01

    Data on levels of irradiation on NPP operating in different regions of the world obtained from the data of the International Information System ISOE created by IAEA in association with the Nuclear Energetic Agency OECD are performed. Effect of commissioning new NPP, sacrifice of radiation situation at the Ignalina NPP in 1996, importance of the development and introduction of programs on perfecting of radiation protection and culture of safety are noted [ru

  11. Potential implications of the bystander effect on TCP and EUD when considering target volume dose heterogeneity.

    Science.gov (United States)

    Balderson, Michael J; Kirkby, Charles

    2015-01-01

    In light of in vitro evidence suggesting that radiation-induced bystander effects may enhance non-local cell killing, there is potential for impact on radiotherapy treatment planning paradigms such as the goal of delivering a uniform dose throughout the clinical target volume (CTV). This work applies a bystander effect model to calculate equivalent uniform dose (EUD) and tumor control probability (TCP) for external beam prostate treatment and compares the results with a more common model where local response is dictated exclusively by local absorbed dose. The broad assumptions applied in the bystander effect model are intended to place an upper limit on the extent of the results in a clinical context. EUD and TCP of a prostate cancer target volume under conditions of increasing dose heterogeneity were calculated using two models: One incorporating bystander effects derived from previously published in vitro bystander data ( McMahon et al. 2012 , 2013a); and one using a common linear-quadratic (LQ) response that relies exclusively on local absorbed dose. Dose through the CTV was modelled as a normal distribution, where the degree of heterogeneity was then dictated by changing the standard deviation (SD). Also, a representative clinical dose distribution was examined as cold (low dose) sub-volumes were systematically introduced. The bystander model suggests a moderate degree of dose heterogeneity throughout a target volume will yield as good or better outcome compared to a uniform dose in terms of EUD and TCP. For a typical intermediate risk prostate prescription of 78 Gy over 39 fractions maxima in EUD and TCP as a function of increasing SD occurred at SD ∼ 5 Gy. The plots only dropped below the uniform dose values for SD ∼ 10 Gy, almost 13% of the prescribed dose. Small, but potentially significant differences in the outcome metrics between the models were identified in the clinically-derived dose distribution as cold sub-volumes were introduced. In terms of

  12. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, So Ra; Min, Byung Il; Park, Kihyun; Yang, Byung Mo; Suh, Kyung Suk [Nuclear Environmental Safety Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-12-15

    The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment.

  13. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR

    International Nuclear Information System (INIS)

    Kim, So Ra; Min, Byung Il; Park, Kihyun; Yang, Byung Mo; Suh, Kyung Suk

    2016-01-01

    The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment

  14. Trend of patient radiation doses in medical examination in Japan

    International Nuclear Information System (INIS)

    Suzuki, Shoichi

    2013-01-01

    We have investigated radiation doses to patients in selected types of examinations in Japan since 1974 and have analyzed the trend of patient radiation doses during a period of 37 years. This study covered regular plain X-ray scanning (including mammography) and computed tomography (CT) scanning. Dose evaluation was performed in terms of entrance skin dose (ESD) for regular plain X-ray scanning, average glandular dose (AGD) for mammography, and volume CT dose index (CTDIvol) for CT scanning. Evaluation was performed in 26 orientations at 21 sites for regular plain X-rays, and for cranial, thoracic, and abdominal scans of children and adults for CT scanning. With the exception of chest X-rays, the dose during regular plain X-ray scanning had decreased by approximately 50% compared with scans performed in 1974. The dose during mammography had decreased to less than 10% of its former level. In scans performed in 2011, dose at all sites were within International Atomic Energy Authority (IAEA) guidance levels. The increasing use of multiple detectors in CT scanning devices was evident in CT scanning. A comparison of doses from cranial non-helical scans performed in 2007 and 2011 found that the latter were higher. An examination of changes in doses between 1997 and 2011 revealed that doses had tended to increase in cranial scans of adults, but had hardly changed at all in abdominal scans. Doses during CT scanning of children were around half those for adults in cranial, thoracic, and abdominal scans. We have ascertained changes in the doses to which patients have been exposed during X-ray scanning in Japan. (author)

  15. Radiation-dose consequences of acid rain

    International Nuclear Information System (INIS)

    Sheppard, S.C.; Sheppard, M.I.; Mitchell, J.H.

    1987-01-01

    Acid rain causes accelerated mobilization of many materials in soils. Natural and anthropogenic radionuclides, especially Ra and Cs, are among these materials. Generally, a decrease in soil pH by 1 unit will cause increases in mobility and plant uptake by factors of 2 to 7. Several simulation models were tested with most emphasis on an atmospherically driven soil model that predicts water and nuclide flow through a soil profile. We modelled a typical, acid rain sensitive soil using meterological data from Geraldton, Ontario. The results, within the range of effects on the soil expected from acidification, showed direct proportionality between the mobility of the nuclides and dose. Based on the literature available, a decrease in pH of 1 unit may increase the mobility of Ra and Cs by a factor or 2 or more. This will lead to increases in plant uptake and ultimate dose to man of about the same extent

  16. Chronic low dose radiation exposure and oxidative stress in radiation workers

    International Nuclear Information System (INIS)

    Ali, S.S.; Bhatt, M.B.; Kulkarni, MM.; Rajan, R.; Singh, B.B.; Venkataraman, G.

    1996-01-01

    Free radicals have been implicated in the pathogenesis of several human diseases. In this study free radical stress due to low dose chronic radiation exposures of radiation workers was examined as a possible atherogenic risk factor. Data on lipid profiles, lipid peroxidation and reduced glutathione content in blood indicated an absence of correlation with radiation doses up to 125 mSv. (author). 13 refs., 1 fig

  17. Biological impact of high-dose and dose-rate radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Maliev, V.; Popov, D. [Russian Academy of Science, Vladicaucas (Russian Federation); Jones, J.; Gonda, S. [NASA -Johnson Space Center, Houston (United States); Prasad, K.; Viliam, C.; Haase, G. [Antioxida nt Research Institute, Premier Micronutrient Corporation, Novato (United States); Kirchin, V. [Moscow State Veterinary and Biotechnology Acade my, Moscow (Russian Federation); Rachael, C. [University Space Research Association, Colorado (United States)

    2006-07-01

    Experimental anti-radiation vaccine is a power tool of immune - prophylaxis of the acute radiation disease. Existing principles of treatment of the acute radiation dis ease are based on a correction of developing patho-physiological and biochemical processes within the first days after irradiation. Protection from radiation is built on the general principles of immunology and has two main forms - active and passive immunization. Active immunization by the essential radiation toxins of specific radiation determinant (S.D.R.) group allows significantly reduce the lethality and increase duration of life among animals that are irradiated by lethal and sub-lethal doses of gamma radiation.The radiation toxins of S.D.R. group have antigenic properties that are specific for different forms of acute radiation disease. Development of the specific and active immune reaction after intramuscular injection of radiation toxins allows optimize a manifestation of a clinical picture and stabilize laboratory parameters of the acute radiation syndromes. Passive immunization by the anti-radiation serum or preparations of immune-globulins gives a manifestation of the radioprotection effects immediately after this kind of preparation are injected into organisms of mammals. Providing passive immunization by preparations of anti-radiations immune-globulins is possible in different periods of time after radiation. Providing active immunization by preparations of S.D.R. group is possible only to achieve a prophylaxis goal and form the protection effects that start to work in 18 - 35 days after an injection of biological active S.D.R. substance has been administrated. However active and passive immunizations by essential anti-radiation toxins and preparations of gamma-globulins extracted from a hyper-immune serum of a horse have significantly different medical prescriptions for application and depend on many factors like a type of radiation, a power of radiation, absorption doses, a time of

  18. Biological impact of high-dose and dose-rate radiation exposure

    International Nuclear Information System (INIS)

    Maliev, V.; Popov, D.; Jones, J.; Gonda, S.; Prasad, K.; Viliam, C.; Haase, G.; Kirchin, V.; Rachael, C.

    2006-01-01

    Experimental anti-radiation vaccine is a power tool of immune - prophylaxis of the acute radiation disease. Existing principles of treatment of the acute radiation dis ease are based on a correction of developing patho-physiological and biochemical processes within the first days after irradiation. Protection from radiation is built on the general principles of immunology and has two main forms - active and passive immunization. Active immunization by the essential radiation toxins of specific radiation determinant (S.D.R.) group allows significantly reduce the lethality and increase duration of life among animals that are irradiated by lethal and sub-lethal doses of gamma radiation.The radiation toxins of S.D.R. group have antigenic properties that are specific for different forms of acute radiation disease. Development of the specific and active immune reaction after intramuscular injection of radiation toxins allows optimize a manifestation of a clinical picture and stabilize laboratory parameters of the acute radiation syndromes. Passive immunization by the anti-radiation serum or preparations of immune-globulins gives a manifestation of the radioprotection effects immediately after this kind of preparation are injected into organisms of mammals. Providing passive immunization by preparations of anti-radiations immune-globulins is possible in different periods of time after radiation. Providing active immunization by preparations of S.D.R. group is possible only to achieve a prophylaxis goal and form the protection effects that start to work in 18 - 35 days after an injection of biological active S.D.R. substance has been administrated. However active and passive immunizations by essential anti-radiation toxins and preparations of gamma-globulins extracted from a hyper-immune serum of a horse have significantly different medical prescriptions for application and depend on many factors like a type of radiation, a power of radiation, absorption doses, a time of

  19. Millirems, microsieverts and radiation dose management

    International Nuclear Information System (INIS)

    Youell, F.P.

    1989-01-01

    Whilst the radiological impact of nuclear power stations on members of the public and station staff is under constant scrutiny, the generally low level of impact under normal operating conditions is not sufficiently appreciated. This paper sets down the radiological criteria against which the AGR stations have been designed and describes the measures taken to reduce the radiation exposure of members of the public and station staff. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Munira A Kadhim

    2010-03-05

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

  1. Capture and analysis of radiation dose reports for radiology

    International Nuclear Information System (INIS)

    Midgley, S.M.

    2014-01-01

    Radiographic imaging systems can produce records of exposure and dose parameters for each patient. A variety of file formats are in use including plain text, bit map images showing pictures of written text and radiation dose structured reports as text or extended markup language files. Whilst some of this information is available with image data on the hospital picture archive and communication system, access is restricted to individual patient records, thereby making it difficult to locate multiple records for the same scan protocol. This study considers the exposure records and dose reports from four modalities. Exposure records for mammography and general radiography are utilized for repeat analysis. Dose reports for fluoroscopy and computed tomography (CT) are utilized to study the distribution of patient doses for each protocol. Results for dosimetric quantities measured by General Radiography, Fluoroscopy and CT equipment are summarised and presented in the Appendix. Projection imaging uses the dose (in air) area product and derived quantities including the dose to the reference point as a measure of the air kerma reaching the skin, ignoring movement of the beam for fluoroscopy. CT uses the dose indices CTDIvol and dose length product as a measure of the dose per axial slice, and to the scanned volume. Suitable conversion factors are identified and used to estimate the effective dose to an average size patient (for CT and fluoroscopy) and the entrance skin dose for fluoroscopy.

  2. 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.

  3. Radiation doses to the staff of a nuclear cardiology department

    International Nuclear Information System (INIS)

    Tsapaki, V.; Koutelou, M.; Theodorakos, A.; Kouzoumi, A.; Kitziri, S.; Tsiblouli, S.; Vardalaki, E.; Kyrozi, E.; Kouttou, S.

    2002-01-01

    The last years, new radiopharmaceuticals are used in a Nuclear Medicine (NM) Department. Nowadays, Single Photon Emission Computed Tomography (SPECT) is a method of routine imaging, a fact that has required increased levels of radioactivity in certain patient examinations. The staff that is more likely to receive the greatest radiation dose in a NM Department is the technologist who deals with performance of patient examination and injection of radioactive material and the nurse who is caring for the patients visiting the Department some of which being totally helpless. The fact that each NM Dept possesses equipment with certain specifications, deals with various kind of patients, has specific design and radiation protection measures which can differ from other NM Depts and uses various examination protocols, makes essential the need to investigate the radiation doses received by each member of the staff, so as to continuously monitor doses and take protective measures if required, control less experienced staff and ensure that radiation dose levels are kept as low as possible at all times. The purpose of the current study was to evaluate radiation dose to the nuclear cardiology department staff by thermoluminescent dosemeters (TLDs) placed on the the skin at thyroid and abdominal region as well as evaluating protection measures taken currently in the Dept

  4. Construction of data base for radiation safety assessment of low dose ionizing radiation

    International Nuclear Information System (INIS)

    Saigusa, Shin

    2001-01-01

    Data base with an electronic text on the safety assessment of low dose ionizing radiation have been constructed. The contents and the data base system were designed to provide useful information to Japanese citizens, radiation specialists, and decision makers for a scientific and reasonable understanding of radiation health effects, radiation risk assessment, and radiation protection. The data base consists of the following four essential parts, namely, ORIGINAL DESCRIPTION, DETAILED INFORMATION, TOPIC INFORMATION, and RELATED INFORMATION. The first two parts of the data base are further classified into following subbranches: Radiobiological effects, radiation risk assessment, and radiation exposure and protection. (author)

  5. [Comparison of dose calculation algorithms in stereotactic radiation therapy in lung].

    Science.gov (United States)

    Tomiyama, Yuki; Araki, Fujio; Kanetake, Nagisa; Shimohigashi, Yoshinobu; Tominaga, Hirofumi; Sakata, Jyunichi; Oono, Takeshi; Kouno, Tomohiro; Hioki, Kazunari

    2013-06-01

    Dose calculation algorithms in radiation treatment planning systems (RTPSs) play a crucial role in stereotactic body radiation therapy (SBRT) in the lung with heterogeneous media. This study investigated the performance and accuracy of dose calculation for three algorithms: analytical anisotropic algorithm (AAA), pencil beam convolution (PBC) and Acuros XB (AXB) in Eclipse (Varian Medical Systems), by comparison against the Voxel Monte Carlo algorithm (VMC) in iPlan (BrainLab). The dose calculations were performed with clinical lung treatments under identical planning conditions, and the dose distributions and the dose volume histogram (DVH) were compared among algorithms. AAA underestimated the dose in the planning target volume (PTV) compared to VMC and AXB in most clinical plans. In contrast, PBC overestimated the PTV dose. AXB tended to slightly overestimate the PTV dose compared to VMC but the discrepancy was within 3%. The discrepancy in the PTV dose between VMC and AXB appears to be due to differences in physical material assignments, material voxelization methods, and an energy cut-off for electron interactions. The dose distributions in lung treatments varied significantly according to the calculation accuracy of the algorithms. VMC and AXB are better algorithms than AAA for SBRT.

  6. Occupational radiation exposure to low doses of ionizing radiation and female breast cancer

    International Nuclear Information System (INIS)

    Adelina, P.; Bliznakov, V.; Bairacova, A.

    2003-01-01

    The aim of this study is to examine the relationship between past occupational radiation exposure to low doses of ionizing radiation and cases of diagnosed and registered breast cancer [probability of causation - PC] among Bulgarian women who have used different ionizing radiation sources during their working experience. The National Institute of Health (NIH) in US has developed a method for estimating the probability of causation (PC) between past occupational radiation exposure to low doses of ionizing radiation and cases of diagnosed cancer. We have used this method. A group of 27 women with diagnosed breast cancer has been studied. 11 of them are former workers in NPP - 'Kozloduy', and 16 are from other sites using different sources of ionizing radiation. Analysis was performed for 14 women, for whom full personal data were available. The individual radiation dose for each of them is below 1/10 of the annual dose limit, and the highest cumulative dose for a period of 14 years of occupational exposure is 50,21 mSv. The probability of causation (PC) values in all analyzed cases are below 1%, which confirms the extremely low probability of causation (PC) between past occupational radiation exposure to low doses of ionizing radiation and occurring cases of breast cancer. (orig.)

  7. Review of European research trends of low dose radiation risk

    International Nuclear Information System (INIS)

    Iwasaki, Toshiyasu; Yoshida, Kazuo

    2010-01-01

    Large research projects on low dose radiation effects in Europe and US over the past decade have provided limited scientific knowledge which could underpin the validation of radiation protection systems. Recently in Europe, there have been repeated discussions and dialogues to improve the situation, and as the consequence, the circumstances surrounding low dose radiation risks are changing. In 2009, Multidisciplinary European Low Dose Initiative (MELODI) was established as a trans-national organization capable of ensuring appropriate governance of research in the pursuit of a long term shared vision, and Low Dose Research towards Multidisciplinary Integration (DoReMi) network was launched in 2010 to achieve fairly short term results in order to prove the validity of the MELODI approach. It is expected to be very effective and powerful activities to facilitate the reduction of uncertainties in the understanding of low dose risks, but the regulatory requests rushing the reinforcement of radiological protection regulations based on the precautional principles are more increasing. To develop reasonable radiological protection systems based on scientific evidences, we need to accelerate to collect scientific evidences which could directly underpin more appropriate radiation protection systems even in Japan. For the purpose, we Japan need to develop from an independent standpoint and share as a multidisciplinary vision a long term and holistic research strategy which enables to enhance Japanese advantages such as low dose rate facilities and animal facilities, as soon as possible. (author)

  8. Recent trend of radiation doses of medical workers

    Energy Technology Data Exchange (ETDEWEB)

    Anzai, I [Tokyo Univ. (Japan). Faculty of Medicine; Tanaka, M; Nakamura, S; Nawa, H; Nukazawa, A

    1981-10-01

    Radiation doses of medical workers in Japan between 1976 and 1979 were analysed based on the data provided by a film badge servicing company. Average annual radiation doses between April, 1978 and March, 1979 were 129 mrems for 2556 doctors, 108 mrems for 2074 radiographers, and 60 mrems for 1915 nurses. It was also suggested that the log-normal distribution could provide a good fit to the frequency distribution of radiation doses of these medical staffs. Time series data of monthly average doses during the period between April, 1976 and March, 1979 were analysed using a computer code named EPA that had been developed by the Japanese Economic Planning Agency. The EPA code separated the original time series data into three components, i.e., the trend and cycle factor, the seasonal factor and the irregular factor based on a multiplicative model. The results of analyses strongly suggested that there existed a significant common pattern among the trend factors of doctors, radiographers and nurses. The similar phenomenon was also observed about the seasonal factors. Some specific cases of medical workers who received considerably high radiation doses were studied, and it was pointed out that, in order to lower the doses of medical workers, the factors which are peculiar to each medical facility must be precisely examined in addition to the strengthening of general radiological protective measures.

  9. Target volumes in gastric cancer radiation therapy

    International Nuclear Information System (INIS)

    Caudry, M.; Maire, J.P.; Ratoanina, J.L.; Escarmant, P.

    2001-01-01

    The spread of gastric adenocarcinoma may follow three main patterns: hemato-genic, lymphatic and intraperitoneal. A GTV should be considered in preoperative or exclusive radiation therapy. After non-radical surgery, a 'residual GTV' will be defined with the help of the surgeon. The CTV encompasses three intricated volumes. a) A 'tumor bed' volume. After radical surgery, local recurrences appear as frequent as distant metastases. The risk depends upon the depth of parietal invasion and the nodal status. Parietal infiltration may extend beyond macroscopic limits of the tumor, especially in dinitis plastica. Therefore this volume will include: the tumor and the remaining stomach or their 'bed of resection', a part of the transverse colon, the duodenum, the pancreas and the troncus of the portal vein. In postoperative RT, this CTV also includes the jejuno-gastric or jejuno-esophageal anastomosis. b) A peritoneal volume. For practical purposes, two degrees of spread must be considered: (1) contiguous microscopic extension from deeply invasive T3 and T4 tumors, that remain amenable to local sterilization with doses of 45-50 Gy, delivered in a CTV including the peritoneal cavity at the level of the gastric bed, and under the parietal incision; (2) true 'peritoneal carcinomatosis', with widespread seeds, where chemotherapy (systemic or intraperitoneal) is more appropriate. c) A lymphatic volume including the lymph node groups 1 to 16 of the Japanese classification. This volume must encompass the hepatic pedicle and the splenic hilum. In proximal tumors, it is possible to restrict the lover part of the CTV to the lymphatic volume, and therefore to avoid irradiation of large intestinal and renal volumes. In distal and proximal tumors, involvement of resection margins is of poor prognosis -a radiation boost must be delivered at this level. The CTV in tumors of the cardia should encompass the lover part of the thoracic esophagus and the corresponding posterior mediastinum. In

  10. Dose Escalated Liver Stereotactic Body Radiation Therapy at the Mean Respiratory Position

    International Nuclear Information System (INIS)

    Velec, Michael; Moseley, Joanne L.; Dawson, Laura A.; Brock, Kristy K.

    2014-01-01

    Purpose: The dosimetric impact of dose probability based planning target volume (PTV) margins for liver cancer patients receiving stereotactic body radiation therapy (SBRT) was compared with standard PTV based on the internal target volume (ITV). Plan robustness was evaluated by accumulating the treatment dose to ensure delivery of the intended plan. Methods and Materials: Twenty patients planned on exhale CT for 27 to 50 Gy in 6 fractions using an ITV-based PTV and treated free-breathing were retrospectively evaluated. Isotoxic, dose escalated plans were created on midposition computed tomography (CT), representing the mean breathing position, using a dose probability PTV. The delivered doses were accumulated using biomechanical deformable registration of the daily cone beam CT based on liver targeting at the exhale or mean breathing position, for the exhale and midposition CT plans, respectively. Results: The dose probability PTVs were on average 38% smaller than the ITV-based PTV, enabling an average ± standard deviation increase in the planned dose to 95% of the PTV of 4.0 ± 2.8 Gy (9 ± 5%) on the midposition CT (P<.01). For both plans, the delivered minimum gross tumor volume (GTV) doses were greater than the planned nominal prescribed dose in all 20 patients and greater than the planned dose to 95% of the PTV in 18 (90%) patients. Nine patients (45%) had 1 or more GTVs with a delivered minimum dose more than 5 Gy higher with the midposition CT plan using dose probability PTV, compared with the delivered dose with the exhale CT plan using ITV-based PTV. Conclusions: For isotoxic liver SBRT planned and delivered at the mean respiratory, reduced dose probability PTV enables a mean escalation of 4 Gy (9%) in 6 fractions over ITV-based PTV. This may potentially improve local control without increasing the risk of tumor underdosing

  11. Monte Carlo-based dose reconstruction in a rat model for scattered ionizing radiation investigations.

    Science.gov (United States)

    Kirkby, Charles; Ghasroddashti, Esmaeel; Kovalchuk, Anna; Kolb, Bryan; Kovalchuk, Olga

    2013-09-01

    In radiation biology, rats are often irradiated, but the precise dose distributions are often lacking, particularly in areas that receive scatter radiation. We used a non-dedicated set of resources to calculate detailed dose distributions, including doses to peripheral organs well outside of the primary field, in common rat exposure settings. We conducted a detailed dose reconstruction in a rat through an analog to the conventional human treatment planning process. The process consisted of: (i) Characterizing source properties of an X-ray irradiator system, (ii) acquiring a computed tomography (CT) scan of a rat model, and (iii) using a Monte Carlo (MC) dose calculation engine to generate the dose distribution within the rat model. We considered cranial and liver irradiation scenarios where the rest of the body was protected by a lead shield. Organs of interest were the brain, liver and gonads. The study also included paired scenarios where the dose to adjacent, shielded rats was determined as a potential control for analysis of bystander effects. We established the precise doses and dose distributions delivered to the peripheral organs in single and paired rats. Mean doses to non-targeted organs in irradiated rats ranged from 0.03-0.1% of the reference platform dose. Mean doses to the adjacent rat peripheral organs were consistent to within 10% those of the directly irradiated rat. This work provided details of dose distributions in rat models under common irradiation conditions and established an effective scenario for delivering only scattered radiation consistent with that in a directly irradiated rat.

  12. Impact of radiation technique, radiation fraction dose, and total cisplatin dose on hearing. Retrospective analysis of 29 medulloblastoma patients

    International Nuclear Information System (INIS)

    Scobioala, Sergiu; Kittel, Christopher; Ebrahimi, Fatemeh; Wolters, Heidi; Eich, Hans Theodor; Parfitt, Ross; Matulat, Peter; Am Zehnhoff-Dinnesen, Antoinette

    2017-01-01

    To analyze the incidence and degree of sensorineural hearing loss (SNHL) resulting from different radiation techniques, fractionation dose, mean cochlear radiation dose (D mean ), and total cisplatin dose. In all, 29 children with medulloblastoma (58 ears) with subclinical pretreatment hearing thresholds participated. Radiotherapy (RT) and cisplatin had been applied sequentially according to the HIT MED Guidance. Audiological outcomes up to the latest follow-up (median 2.6 years) were compared. Bilateral high-frequency SNHL was observed in 26 patients (90%). No significant differences were found in mean hearing threshold between left and right ears at any frequency. A significantly better audiological outcome (p < 0.05) was found after tomotherapy at the 6 kHz bone-conduction threshold (BCT) and left-sided 8 kHz air-conduction threshold (ACT) than after a combined radiotherapy technique (CT). Fraction dose was not found to have any impact on the incidence, degree, and time-to-onset of SNHL. Patients treated with CT had a greater risk of SNHL at high frequencies than tomotherapy patients even though D mean was similar. Increase in severity of SNHL was seen when the total cisplatin dose reached above 210 mg/m 2 , with the highest abnormal level found 8-12 months after RT regardless of radiation technique or fraction dose. The cochlear radiation dose should be kept as low as possible in patients who receive simultaneous cisplatin-based chemotherapy. The risk of clinically relevant HL was shown when D mean exceeds 45 Gy independent of radiation technique or radiation regime. Cisplatin ototoxicity was shown to have a dose-dependent effect on bilateral SNHL, which was more pronounced in higher frequencies. (orig.) [de

  13. Techniques and radiation dose in CT examinations of adult patients

    International Nuclear Information System (INIS)

    Elameen, S. E. A.

    2010-06-01

    The use of CT in medical diagnosis delivers radiation dose to patients that are higher than those from other radiological procedures. Lake of optimized protocols could be an additional source of increased dose. The aim of this study was to measure radiation doses in CT examination of the adults in three Sudanese hospitals. Details were obtained from approximately 160 CT examination carried out in 3 hospitals (3 CT scanners). Effective dose was calculated for each examination using CT dose indices. exposure related parameters and CT D1- to- effective dose conversion factors. CT air kerma index (CT D1) and dose length products (DLP) determined were below the established international reference dose levels. The mean effective doses in this study for the head, chest, and abdomen are 0.82, 3.7 and 5.4 mGy respectively. These values were observed that the effective dose per examination was lower in Sudan than in other countries. The report of a CT survey done in these centers indicates that the mean DLP values for adult patients were ranged from 272-460 mGy cm (head) 195-995 mGy cm (chest), 270-459 mGy cm (abdomen). There are a number of observed parameters that greatly need optimization, such as minimize the scan length, without missing any vital anatomical regions, modulation of exposure parameters (kV, mA, exposure time, and slice thickness) based on patient size and age. Another possible method is through use of contrast media only to optimize diagnostic yield. The last possible method is the use of radio protective materials for protection however, in order to achieve the above optimization strategies: there is great demand to educate CT personnel on the effects of scan parameter settings on radiation dose to patients and image quality required for accurate diagnosis. (Author)

  14. Radiation absorbed doses at radiographic examination of third molars

    International Nuclear Information System (INIS)

    Rehnmark-Larsson, S.; Stenstroem, B.; Julin, P.; Richter, S.; Huddinge University Hospital

    1981-01-01

    The radiation absorbed doses to critical organs, i.e. the thyroid and salivary glands and the gonadal region, were measured at radiographic examination of third molars. A tissue equivalent phantom was used together with ionization chamber detectors and TLDs. The greatest thyroid dose, 35 μGy, came from a mandibular disto-oblique projection with the circular tube collimator and Ultra-Speed film. The doses in different parts of the parotid gland from the disto-oblique mandibular projection with Ultra-Speed film ranged between 2.65 and 0.052 mGy. the corresponding doses in the submandibular gland were 1.74 mGy beneath the mandible and 0.458 mGy in the fovea. A rectangular tube collimator reduced the doses by approximately 50 %. The Ekta-Speed film requirted approximately 40 % lower exposure than the Ultra-Speed film. A horizontal radiation shield reduced the thyroid doses by between 12 and 46 % and the gonadal doses by between 50 and 95 %. The reduction effect from the shield was relatively greater when using the larger aperture of the tube collimator. Combinations of leaded aprons and soft leaded collars reduced the thyroid doses between 15 and 42 % and the gonadal doses by two orders of magnitude. (Authors)

  15. Building shielding effects on radiation doses from routine radionuclide releases

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1977-01-01

    In calculating population doses from the release of radionuclides to the atmosphere, it is usually assumed that man spends all of his time outdoors standing on a smooth infinite plane. Realistically, however, man spends most of the time indoors, so that substantial reductions in radiation doses may result compared with the usual estimates. Calculational models were developed to study the effects of building structures on radiation doses from routine releases of radionuclides to the atmosphere. Both internal dose from inhaled radionuclides and external photon dose from airborne and surface-deposited radionuclides are considered. The effect of building structures is described quantitatively by a dose reduction factor, which is the ratio of the dose inside a structure to the corresponding dose with no structure present. The internal dose from inhaled radionuclides is proportional to the radionuclide concentration in the air. Assuming that the outdoor airborne concentration is constant with time, the time-dependence of the indoor airborne concentration in terms of the structure air ventilation rate, the deposition velocities for radionuclides on the inside floor, walls, and ceiling, and the radioactive decay constant, were calculated

  16. Radiation effects on and dose enhancement of electronic materials

    International Nuclear Information System (INIS)

    Srour, J.R.; Long, D.M.

    1984-01-01

    This book describes radiation effects on and dose enhancement factors for electronic materials. Alteration of the electrical properties of solid-state devices and integrated circuits by impinging radiation is well-known. Such changes may cause an electronic subsystem to fail, thus there is currently great interest in devising methods for avoiding radiation-induced degradation. The development of radiation-hardened devices and circuits is an exciting approach to solving this problem for many applications, since it could minimize the need for shielding or other system hardening techniques. Part 1 describes the basic mechanisms of radiation effects on electronic materials, devices, and integrated circuits. Radiation effects in bulk silicon and in silicon devices are treated. Ionizing radiation effects in silicon dioxide films and silicon MOS devices are discussed. Single event phenomena are considered. Key literature references and a bibliography are provided. Part II provides tabulations of dose enhancement factors for electronic devices in x-ray and gamma-ray environments. The data are applicable to a wide range of semiconductor devices and selected types of capacitors. Radiation environments discussed find application in system design and in radiation test facilities

  17. Health Effects of Exposure to Low Dose of Radiation

    International Nuclear Information System (INIS)

    Alatas, Zubaidah

    2003-01-01

    Human beings are exposed to natural radiation from external sources include radionuclides in the earth and cosmic radiation, and by internal radiation from radionuclides, mainly uranium and thorium series, incorporated into the body. Living systems have adapted to the natural levels of radiation and radioactivity. But some industrial practices involving natural resources enhance these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Biological effects of ionizing radiation are the outcomes of physical and chemical processes that occur immediately after the exposure, then followed by biological process in the body. These processes will involve successive changes in the molecular, cellular, tissue and whole organism levels. Any dose of radiation, no matter how small, may produce health effects since even a single ionizing event can result in DNA damage. The damage to DNA in the nucleus is considered to be the main initiating event by which radiation causes damage to cells that results in the development of cancer and hereditary disease. It has also been indicated that cytogenetic damage can occur in cells that receive no direct radiation exposure, known as bystander effects. This paper reviews health risks of low dose radiation exposure to human body causing stochastic effects, i.e. cancer induction in somatic cells and hereditary disease in genetic cells. (author)

  18. Low dose radiation and diabetes mellitus

    International Nuclear Information System (INIS)

    Zhao Hongguang; Gong Shouliang; Cai Lu

    2006-01-01

    Induction of hormesis and adaptive response by low-dose radiatio (LDR) has been extensively indicated. It's mechanism may be related with the protective protein and antioxidants that LDR induced, which take effects on the diabetes mellitus (DM) and other diseases. This review will summarize available dat with emphasis on three points: the preventive effect of LDR on the development of diabetes, the therapeutic effect of LDR on diabetic complications and possible mechanisms by which LDR prevents the development of diabetes and diabetic complications. Finally, the perspectives of LDR clinical, diabetes-related implication are discussed. (authors)

  19. Biochemical and immunological responses to low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Shabon, M.H.; Sayed, Z.S.; Mahdy, E.M.; El-Gawish, M.A.; Shosha, W.

    2006-01-01

    Malondialdehyde, lactate dehydrogenase, iron concentration, IL-6 and IL-1b concentration, hemoglobin content, red cells, white cells and platelet counts were determined in seventy-two male albino rats divided into two main groups. The first one was subdivided into 7 subgroups; control and 6 irradiated subgroups with 0.1, 0.2, 0.3, 0.5, 0.7 and 1 Gy single dose of gamma radiation. The other was subdivided into 4 subgroups irradiated with fractionated doses of gamma radiation; three groups were irradiated with 0.3, 0.7 and 1 Gy (0.1 Gy/day) and the last subgroup with 1 Gy (0.2 Gy/day). All animals were sacrificed after three days of the last irradiation dose. The results revealed that all biochemical parameters were increased in rats exposed to fractionated doses more than the single doses. Hematological parameters were decreased in rats exposed to single doses more than the fractionated ones. In conclusion, the data of this study highlights the stimulatory effect of low ionizing radiation doses (= 1 Gy), whether single or fractionated, on some biochemical and immunological parameters

  20. Radiation dose to neonates on a Special Care Baby Unit

    International Nuclear Information System (INIS)

    Faulkner, K.; Barry, J.L.; Smalley, P.

    1989-01-01

    The skin entrance dose to neonates on a special care baby unit was estimated from a knowledge of the technique factors, X-ray tube output and backscatter factors. Normalized organ dose data were employed to estimate radiation dose to a number of critical organs. Methods of reducing radiation dose to neonates were investigated. Initially, this involved changing the radiographic technique factors and introducing a lead rubber adjustable collimator, placed on top of the incubator, in addition to light beam diaphragms on the X-ray tube. These modifications to the examination technique appeared to reduce average entrance dose per radiograph from 92 μGy, to 58 μGy, a reduction of 37%. Later, a rare-earth film-screen combination was introduced to replace existing fast calcium tungstate screens. This enabled average entrance dose per radiograph to be reduced to 39 μGy, a further reduction of 33%. The mean radiation dose to a neonate is mainly determined by the number of radiographs. (author)

  1. Radiation dose to neonates on a Special Care Baby Unit

    Energy Technology Data Exchange (ETDEWEB)

    Faulkner, K.; Barry, J.L.; Smalley, P.

    1989-03-01

    The skin entrance dose to neonates on a special care baby unit was estimated from a knowledge of the technique factors, X-ray tube output and backscatter factors. Normalized organ dose data were employed to estimate radiation dose to a number of critical organs. Methods of reducing radiation dose to neonates were investigated. Initially, this involved changing the radiographic technique factors and introducing a lead rubber adjustable collimator, placed on top of the incubator, in addition to light beam diaphragms on the X-ray tube. These modifications to the examination technique appeared to reduce average entrance dose per radiograph from 92 ..mu..Gy, to 58 ..mu..Gy, a reduction of 37%. Later, a rare-earth film-screen combination was introduced to replace existing fast calcium tungstate screens. This enabled average entrance dose per radiograph to be reduced to 39 ..mu..Gy, a further reduction of 33%. The mean radiation dose to a neonate is mainly determined by the number of radiographs.

  2. Radiation oncology: what can we achieve by optimized dose delivery?

    International Nuclear Information System (INIS)

    Lawrence, T.

    2003-01-01

    Spectacular technical advances have marked the last twenty years in radiation oncology. This revolution began with CT-based planning which was followed by 3D conformal therapy. The latter approach produced two important capabilities. The most obvious was that tumors could be viewed in their true location with respect to normal tissues and treated with beams that were not in the axial plane. A second equally important advance was the development of 3D planning tools such as dose volume histograms. These tools permitted quantitative comparison of treatment plans and have supported the development of models relating normal tissue irradiation to the risk of complication. The '3D hypothesis' - that 3D treatment planning would permit higher doses of radiation to be safely delivered-has been proven. Dose escalation studies have been successfully conducted in the lung (= 100 Gy), liver (= 90 Gy), brain (= 90 Gy), and prostate (= 78 Gy). Prospective phase II and phase III trials suggest improved outcome using these higher doses for tumors in the liver and prostate compared to doses considered acceptable in the 2D era. The next technical revolution is underway, with advances in '4D' radiotherapy (accounting fully for organ motion) and in intensity-modulated radiation therapy (IMRT) to further improve the conformality and accuracy of treatment. Proton therapy will improve dose distributions still further. These improved dose distributions can be combined with more accurate tumor delineation provided by functional imaging to offer the potential for additional dose escalation without toxicity and for improved tumor control. These developments permit us to ask if we are approaching the limits of dose optimization and how (if?) research in radiation delivery should proceed

  3. TLD DRD dose discrepancy: role of beta radiation fields

    International Nuclear Information System (INIS)

    Munish Kumar; Pradhan, S.M.; Bihari, R.R.; Bakshi, A.K.; Chougaonkar, M.P.; Babu, D.A.R.; Gupta, Anil

    2014-01-01

    Ionization chamber based direct reading/pocket dosimeters (DRDs), are used along with the legal dosimeters (thermoluminescent dosimeters-TLDs) for day to day monitoring and control of radiation doses received by radiation workers. The DRDs are routinely used along with the passive dosimeters (TLDs) in nuclear industry at different radiation installations where radiation levels could vary significantly and the possibility of receiving doses beyond investigation levels by radiation workers is not ruled out. Recently, recommendations for dealing with discrepancies between personal dosimeter systems used in parallel were issued by ISO. The present study was performed to measure the response of ionization chamber based pocket dosimeters to various beta sources having energy (E max ) ranging from 0.224 MeV-3.54 MeV. It is expected that the above study will be useful in resolving the disparity between TLD and DRD doses at those radiation installations where radiation workers are likely to be exposed simultaneously from photons and beta particles

  4. Impact of Drug Therapy, Radiation Dose, and Dose Rate on Renal Toxicity Following Bone Marrow Transplantation

    International Nuclear Information System (INIS)

    Cheng, Jonathan C.; Schultheiss, Timothy E.; Wong, Jeffrey Y.C.

    2008-01-01

    Purpose: To demonstrate a radiation dose response and to determine the dosimetric and chemotherapeutic factors that influence the incidence of late renal toxicity following total body irradiation (TBI). Methods and Materials: A comprehensive retrospective review was performed of articles reporting late renal toxicity, along with renal dose, fractionation, dose rate, chemotherapy regimens, and potential nephrotoxic agents. In the final analysis, 12 articles (n = 1,108 patients), consisting of 24 distinct TBI/chemotherapy conditioning regimens were included. Regimens were divided into three subgroups: adults (age ≥18 years), children (age <18 years), and mixed population (both adults and children). Multivariate logistic regression was performed to identify dosimetric and chemotherapeutic factors significantly associated with late renal complications. Results: Individual analysis was performed on each population subgroup. For the purely adult population, the only significant variable was total dose. For the mixed population, the significant variables included total dose, dose rate, and the use of fludarabine. For the pediatric population, only the use of cyclosporin or teniposide was significant; no dose response was noted. A logistic model was generated with the exclusion of the pediatric population because of its lack of dose response. This model yielded the following significant variables: total dose, dose rate, and number of fractions. Conclusion: A dose response for renal damage after TBI was identified. Fractionation and low dose rates are factors to consider when delivering TBI to patients undergoing bone marrow transplantation. Drug therapy also has a major impact on kidney function and can modify the dose-response function

  5. Quantifying the Combined Effect of Radiation Therapy and Hyperthermia in Terms of Equivalent Dose Distributions

    International Nuclear Information System (INIS)

    Kok, H. Petra; Crezee, Johannes; Franken, Nicolaas A.P.; Stalpers, Lukas J.A.; Barendsen, Gerrit W.; Bel, Arjan

    2014-01-01

    Purpose: To develop a method to quantify the therapeutic effect of radiosensitiza