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Sample records for rate intraluminal radiation

  1. Occurrence of chronic esophageal ulcer after high dose rate intraluminal radiation therapy for esophageal cancer

    International Nuclear Information System (INIS)

    Soejima, Toshinori; Hirota, Saeko; Okamoto, Yoshiaki; Obayashi, Kayoko; Takada, Yoshiki

    1995-01-01

    Ninety-eight patients with esophageal cancer were treated by high dose rate intraluminal radiation therapy at the Department of Radiology of the Hyogo Medical Center for Adults between January 1982 and December 1993. Twenty patients with complete response after intraluminal radiation therapy, who were followed up with esophageal fiberscopy in our institute, were reviewed. The one-year cumulative rate of occurrence of esophageal ulcers was 81%, and in 69% of the cases the ulcers occurred from 4 to 8 months after completion of intraluminal radiation therapy. We graded esophageal ulcer by fiberscopic findings. Grade 0 was defined as no ulcer, grade 1 as superficial ulcer, grade 2 as deep ulcer, grade 3 as circumferencial ulcer, and severe stenosis. Factors related to grade were studied, and shorter distances from the source to the surface of the mucosa and lower surface doses of intraluminal radiation therapy appear to reduce the severity as graded on the above scale, of the esophageal ulcer. Four of the five 2-year recurrence-free patients suffered esophageal ulcers, which were cured from 15 to 22 months after intraluminal radiation therapy. However ulcers recurred in two patients, ong term care was thought to be necessary. (author)

  2. High dose rate afterloading intraluminal brachytherapy for advanced inoperable rectal carcinoma

    International Nuclear Information System (INIS)

    Hoskin, Peter J.; Canha, Sandra M. de; Bownes, Peter; Bryant, Linda; Jones, Rob Glynne

    2004-01-01

    Background and purpose: High dose rate intraluminal brachytherapy for tumours of the rectal and anal canal which were inoperable either because of the age and frailty of the patient or because of advanced disease has been evaluated. Patients and methods: In a retrospective review of 50 consecutive patients the two main indications for brachytherapy were as part of a radical radiation programme in those unfit for major surgery (26 patients) or as palliation for advanced or metastatic disease (22 patients). Radical treatment was either sole treatment delivering 6 Gy fraction 2 to 3 times weekly up to 36 Gy or as a boost of 12 Gy after 45 Gy in 25 fractions external beam chemoradiation. Palliative treatments were given predominantly as a single dose of 10 Gy. Results: This was predominantly a group of frail elderly patients with a median age of 82 years (range 35-91). Local tumour response was seen in 21/25 assessable patients with 14 complete responses. Median survival for the entire population was 6 months (range 1-54 months); in patients treated with 'radical' intent this was 25 months (range 1.5-54) and in the palliative group 7.2 months (range 1-37). The most common presenting symptom was bleeding per rectum for which a 64% response rate was obtained with 57% complete responses. Mucous discharge responded in 64% with 28% complete responses. The median duration of response was 7 months. Conclusion: Intraluminal HDR brachytherapy is an effective local treatment for patients otherwise unfit for radical surgery both as a component of radical treatment, or as a simple single palliative procedure

  3. Long-term results of curative intraluminal high dose rate brachytherapy for endobronchial carcinoma

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    Kawamura Hidemasa

    2012-07-01

    Full Text Available Abstract Background The treatment strategy of central lung tumors is not established. Intraluminal brachytherapy (ILBT is widely used for palliative treatment of endobronchial tumors, however, it is also a promising option for curative treatment with limited data. This study evaluates the results after ILBT for endobronchial carcinoma. Method Sixteen-endobronchial carcinoma of 13 patients treated with ILBT in curative intent for 2000 to 2008 were retrospectively reviewed. ILBT using high dose rate 192 iridium thin wire system was performed with 5 Gy/fraction at mucosal surface. The patient age ranged from 57 to 82 years old with median 75 years old. The 16 lesions consisted of 13 central endobronchial cancers including 7 roentgenographically occult lung cancers and 3 of tracheal cancers. Of them, 10 lesions were treated with ILBT of median 20 Gy combined with external beam radiation therapy of median 45 Gy and 6 lesions were treated with ILBT alone of median 25 Gy. Results Median follow-up time was 32.5 months. Two-year survival rate and local control rate were 92.3% and 86.2%, respectively. Local recurrences were observed in 2 lesions. Three patients died due to lung cancer (1 patient and intercurrent disease (2 patients. Complications greater than grade 2 were not observed except for one grade 3 dyspnea. Conclusions ILBT combined with or without EBRT might be a curative treatment option in inoperable endobronchial carcinoma patients with tolerable complication.

  4. Comparative analysis of intraluminal radiation stent in treatment of advanced esophageal carcinoma

    International Nuclear Information System (INIS)

    Guo Jinhe; Teng Gaojun; Zhu Guangyu; He Shicheng; Fang Wen; Deng Gang; Li Guozhao

    2007-01-01

    Objective: To compare the clinical effectiveness of intraluminal radiation stent with that of common covered stent to palliate dysphagia in advanced esophageal cancer. Methods: Fifty three cases were randomly assigned to the experimental group (Group A, n=27) and the control group (Group B, n26). Radiation stents were placed in Group A and common covered stents were placed in Group B. A randomized trial was performed to compare the two groups with respect to complications, relief of dysphagia, and overall survival period. Results: The placement of stents were successful in all the 53 patients. In Group A, no leakage of radiation source was observed through ECT examination, and no displacement of radiation seeds was found through radiography. The follow-up CT showed reduced lesion size compared to presurgical lesion. Three of the 5 patients who underwent uncovered radiation stent placement showed complete necrosis and inflammatory hyperblastosis in tumor tissue adjacent to radiation particles at 2 months follow-up. The lumen of the stents were smooth and had no overgrowth of tumor tissue. Granulation hyperplasia was found at both ends of the stents, prominent at the proximal ends, The incidence of stent- related complications had no significant difference between group A and group B (test, P>0.05). Dysphasia resolved significantly after stent placement in both groups. The improvement of dysphasia was more significant in Group A than in Group B after 2 months of stent placement (1.37±0.56 in group A, 1.82±0.50 in group B,P=0.004). The median survival period was longer in Group A than in Group B (7 months vs 4 months ). The mean survival period was also longer in Group A than in Group B (8.3 months vs 3.5 months). There was a statistically significant difference in the survival period between the two groups (P<0.01). Conclusion: Intraluminal radiation esophageal stent can not only palliate dysphagia but also restrain tumor growth. Palliation period of dysphagia and

  5. High dose rate versus medium dose rate intraluminal brachytherapy in inoperable esophageal carcinoma

    International Nuclear Information System (INIS)

    Langendijk, J.; Jager, J.; Jong, J. de; Rijken, J.; Pannebakker, M.

    1996-01-01

    Introduction: The purpose of this study was to compare the results of medium dose rate (MDR) intraluminal brachytherapy (ILBT) and high dose rate (HDR) ILBT in patients with inoperable esophageal carcinoma, with regard to dysphagia, complication rate and survival. Material and methods: Included were 114 patients with inoperable esophageal cancer who were treated with a single session of ILBT. In all cases a single dose of 15 Gy was administered, calculated at a 1 cm radius. Forty-eight patients were treated with MDR ( 137 Cs)ILBT. In June 1990 MDR was replaced by HDR and from then 66 patients were treated with HDR ( 192 Ir). Dysphagia was prospectively scored using a 5-point scale at 6 weeks, 3, 6, 9 and 12 months. Results: No significant differences were noted between the two groups with regard to pretreatment variables. In patients treated with MDR-ILBT improvement of swallowing ability was noted in 30 out of 42 evaluable patients (71%), no change in 9 (21%) and progression of dysphagia in 3 patients (8%), as compared to 34 out of 59 evaluable patients (58%), 16 (27%) and 6 (15%) resp. in de HDR-ILBT group. In the latter category, progression of dysphagia was caused by fistulae in 2 patients. The differences were not significant (ns). Additional treatment in case of recurrent or persistent dysphagia was needed in 50% of the cases in the MDR-ILBT group as compared to 41% in the HDR-ILBT group (ns). The median survival of the MDR-ILBT group was 3.9 months as compared to 4.3 months in the HDR-ILBT group (ns). In 2 patients (4%) treated with MDR-ILBT bronchio-oesphageal fistulae developed at 6 weeks and 2 months. In the HDR-ILBT group fistulae were noted in 7 cases (11%) at 2 weeks, 4 weeks, 2, 3, 3, 4 and 9 months (ns). In all of these cases persistent of recurrent tumour was present. Conclusions: No significant differences were noted with regard to palliation of dysphagia, survival and complication rate between MDR-ILBT and HDR-ILBT in the management of esophageal

  6. Dosimetric evaluation of a novel high dose rate (HDR) intraluminal / interstitial brachytherapy applicator for gastrointestinal and bladder cancers

    Science.gov (United States)

    Aghamiri, Seyyed Mahmoud Reza; Najarian, Siamak; Jaberi, Ramin

    2010-01-01

    High dose rate (HDR) brachytherapy is one of the accepted treatment modalities in gastro‐intestinal tract and bladder carcinomas. Considering the shortcoming of contact brachytherapy routinely used in gastrointestinal tract in treatment of big tumors or invasive method of bladder treatment, an intraluminal applicator with the capability of insertion into the tumor depth seems to be useful. This study presents some dosimetric evaluations to introduce this applicator to the clinical use. The radiation attenuation characteristics of the applicator were evaluated by means of two dosimetric methods including well‐type chamber and radiochromic film. The proposed 110 cm long applicator has a flexible structure made of stainless steel for easy passage through lumens and a needle tip to drill into big tumors. The 2 mm diameter of the applicator is thick enough for source transition, while easy passage through any narrow lumen such as endoscope or cystoscope working channel is ensured. Well‐chamber results showed an acceptably low attenuation of this steel springy applicator. Performing absolute dosimetry resulted in a correlation coefficient of R=0.9916(p‐value≈10−7) between standard interstitial applicator and the one proposed in this article. This study not only introduces a novel applicator with acceptable attenuation but also proves the response independency of the GAFCHROMIC EBT films to energy. By applying the dose response of the applicator in the treatment planning software, it can be used as a new intraluminal / interstitial applicator. PACS number: 87.53.Bn, 87.53.Jw, 29.40.Cs

  7. Clinical result of high-dose rate intraluminal brachytherapy for esophageal carcinoma with a remote afterloading system

    International Nuclear Information System (INIS)

    Fukuda, Haruyuki; Nakajima, Toshifumi; Tada, Takuhito; Tanaka, Masahiro; Tsumura, Masashi; Onoyama, Yasuto

    1992-01-01

    During the period from 1977 through 1987, 105 patients with esophageal carcinoma were radically treated by radiotherapy. Forty-six patients receiving therapy before August 1982 were all treated by external beam therapy alone (Group 1). Since September 1982, 26 patients were treated by external beam therapy alone (Group 2) and 33 patients were treated by high-dose-rate intraluminal brachytherapy with a remote afterloading system combined with external beam therapy (Group 3). Dose of external beam therapy for Group 1, Group 2 and Group 3 patients were 66.7 Gy, 68.7 Gy and 55.9 Gy on the average. The intraluminal brachytherapy was performed with a total dose of 12 Gy consisting of 3 Gy twice a week. Ten of 72 patients (14%) treated by external beam therapy alone achieved complete response, whereas 14 of 33 patients (42%) treated by high-dose-rate intraluminal brachytherapy combined with external beam therapy had complete response. One-, and 3-year survival rates were 36% and 10% in the Group 1, 32% and 12% in the Group 2 and 56% and 36% in the Group 3. For Group 3, good survival rate was obtained in tumorous type and serrated type. Patients with tumor of less than 5 cm in Group 3 had good survival. The data suggest that the high-dose-rate intraluminal bracytherapy prescribed as a boost therapy following external beam therapy is an effective therapy modality for esophageal carcinoma which is of non-circumferential tumor or less than 5 cm. (author)

  8. Fractionated high dose rate intraluminal brachytherapy in palliation of advanced esophageal cancer

    International Nuclear Information System (INIS)

    Sur, Ranjan K.; Donde, Bernard; Levin, Victor C.; Mannell, Aylwyn

    1998-01-01

    Purpose: To optimize the dose of fractionated brachytherapy for palliation of advanced esophageal cancer. Methods and Materials: One hundred and seventy-two patients with advanced esophageal cancer were randomized to receive 12 Gy/2 fractions (group A); 16 Gy/2 fractions (group B), and 18 Gy/3 fractions (group C) by high dose rate intraluminal brachytherapy (HDRILBT). Treatment was given weekly and dose prescribed at 1 cm from the source axis. Patients were followed up monthly and assessed for dysphagia relief and development of complications. Results: Twenty-two patients died before completing treatment due to advanced disease and poor general condition. The overall survival was 19.4% at the end of 12 months for the whole group (A--9.8%, B--22.46%, C--35.32%; p > 0.05). The dysphagia-free survival was 28.9% at 12 months for the whole group (A--10.8%, B--25.43%, C--38.95%; p > 0.05). Forty-three patients developed fibrotic strictures needing dilatation (A--5 of 35, B--15 of 60, C--23 of 55; p = 0.032). Twenty-seven patients had persistent luminal disease (A--11, B--6, C--10), 15 of which progressed to fistulae (A--7, B--2, C--6; p = 0.032). There was no effect of age, sex, race, histology, performance status, previous dilation, presenting dysphagia score, presenting weight, grade, tumor length, and stage on overall survival, dysphagia-free, and complication-free survival (p > 0.05). On a multivariate analysis, brachytherapy dose (p = 0.002) and tumor length (p = 0.0209) were found to have a significant effect on overall survival; brachytherapy dose was the only factor that had an impact on local tumor control (p = 0.0005), while tumor length was the only factor that had an effect on dysphagia-free survival (p = 0.0475). When compared to other forms of palliation currently available (bypass surgery, laser, chemotherapy, intubation, external radiotherapy), fractionated brachytherapy gave the best results with a median survival of 6.2 months. Conclusions: Fractionated

  9. Impact of concentration and rate of intraluminal drug delivery on absorption and gut wall metabolism of verapamil in humans.

    Science.gov (United States)

    Glaeser, Hartmut; Drescher, Siegfried; Hofmann, Ute; Heinkele, Georg; Somogyi, Andrew A; Eichelbaum, Michel; Fromm, Martin F

    2004-09-01

    In humans gut wall metabolism can be quantitatively as important as hepatic drug metabolism in limiting the systemic exposure to drugs after oral administration. However, it has been proposed that the role of gut wall metabolism might be overemphasized, because high luminal drug concentrations would lead to a saturation of gut wall metabolism. Therefore we investigated the impact of concentration and rate of intraluminal drug delivery on absorption (F(abs)) and gastrointestinal extraction (E(GI)) of a luminally administered cytochrome P450 (CYP) 3A4 substrate (verapamil) using a multilumen perfusion catheter in combination with a stable isotope technique. Two 20-cm-long, adjacent jejunal segments were isolated with the multilumen perfusion catheter in 7 subjects. In this study 80 mg of unlabeled verapamil (d0-verapamil 15 min) was infused into one segment over a 15-minute period, 80 mg of 3-fold deuterated verapamil (d3-verapamil 240 min) was administered over a 240-minute period into the other segment, and simultaneously, 5 mg of 7-fold deuterated verapamil (d7-verapamil) was injected intravenously over a 15-minute period. The rate of intraluminal drug delivery had only a modest effect on bioavailability of the verapamil isotopes (after correction for F abs ) (F/F abs d3-verapamil 240 min versus d0-verapamil 15 min, 0.24 +/- 0.10 versus 0.20 +/- 0.09; P d3-verapamil 240 min was 0.50 +/- 0.18 compared with 0.59 +/- 0.14 for d0 -verapamil 15 min ( P d0-verapamil 15 min ) correlated strongly with E GI (d3-verapamil 240 min ) (r = 0.94, P d0-verapamil 15 min /d3-verapamil 240 min (r = 0.62, P =.03). Substantial gut wall metabolism of verapamil occurs in humans and can be predicted from ex vivo data by use of shed enterocytes. The different intraluminal concentrations and rates of intraluminal drug delivery did not lead to a pronounced saturation of intestinal drug metabolism.

  10. Massive haemoptysis death and other morbidity associated with high dose rate intraluminal radiotherapy for carcinoma of the bronchus

    International Nuclear Information System (INIS)

    Gollins, S.W.; Ryder, W.D.J.; Burt, P.A.; Barber, P.V.; Stout, R.

    1996-01-01

    Four hundred and six patients with primary non-small cell carcinoma of the bronchus causing symptoms due to endobronchial disease, were treated with intraluminal radiotherapy (ILT) using the microSelectron-HDR machine at the Christie Hospital, Manchester, between April 1988 and the end of 1992. An assessment of morbidity for this treatment is presented, particularly with regard to the risk factors and causes of massive haemoptysis death. The most common early side-effect was a mild transient exacerbation of cough which usually resolved within 2-3 weeks. At various times following ILT treatment 83 bronchoscopies were carried out randomly in 55 patients. In bronchoscopies carried out within the first 3 months following ILT, no tumour was visible in 80% of cases. A mucosal radiation reaction score (RRS) was used to grade bronchoscopic appearance after ILT treatment. Overall, 55% of bronchoscopic examinations showed some degree of mucosal radiation reaction. The majority of radiation reactions from 6 months onwards after ILT demonstrated a degree of fibrosis. A radiation reaction was seen more frequently after treatment with 2000 cGy as opposed to 1500 cGy at 1 cm from the central axis of the radiation source. Thirty-two patients were identified who had died from massive haemoptysis (MH) as a terminal event. A Cox multivariate regression analysis showed that the treatment-related factors of increased dose at first ILT (P = 0.004), prior laser treatment at the site of ILT (P = 0.020) and second ILT treatment in the same location as the first ILT treatment (P 0.047), all significantly increased the relative risk of MH death compared with their effect on the relative risk of death from other causes (OC). (In addition a fourth treatment-related factor, namely the concurrent use of ILT and external beam radiotherapy (EB) had a P value of 0.08). Twenty out of 25 assessable MH-death patients (80%) had evidence of recurrent or residual tumour before death but 5 patients (20

  11. Impact of Intraluminal Brachytherapy on Survival Outcome for Radiation Therapy for Unresectable Biliary Tract Cancer: A Propensity-Score Matched-Pair Analysis

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    Yoshioka, Yasuo [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Ogawa, Kazuhiko, E-mail: kogawa@radonc.med.osaka-u.ac.jp [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Oikawa, Hirobumi [Department of Radiology, Iwate Medical University, Iwate (Japan); Onishi, Hiroshi [Department of Radiology, University of Yamanashi, Yamanashi (Japan); Kanesaka, Naoto [Department of Radiology, Tokyo Medical University, Tokyo (Japan); Tamamoto, Tetsuro [Department of Radiation Oncology, Nara Medical University of Medicine, Nara (Japan); Kosugi, Takashi [Department of Radiology, Hamamatsu University School of Medicine, Shizuoka (Japan); Hatano, Kazuo [Department of Radiation Oncology, Chiba Cancer Center, Chiba (Japan); Kobayashi, Masao [Department of Radiology, Jikei University School of Medicine, Tokyo (Japan); Ito, Yoshinori [Department of Radiation Oncology, National Cancer Center Hospital, Tokyo (Japan); Takayama, Makoto [Department of Radiology, Kyorin University School of Medicine, Tokyo (Japan); Takemoto, Mitsuhiro [Department of Radiology, Okayama University, Okayama (Japan); Karasawa, Katsuyuki [Department of Radiation Oncology, Tokyo Metropolitan Komagome Hospital, Tokyo (Japan); Nagakura, Hisayasu [Department of Radiology, KKR Sapporo Medical Center, Hokkaido (Japan); Imai, Michiko [Department of Radiation Oncology, Iwata City Hospital, Shizuoka (Japan); Kosaka, Yasuhiro [Department of Radiation Oncology, Kobe City Medical Center General Hospital, Hyogo (Japan); Yamazaki, Hideya [Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Isohashi, Fumiaki [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Nemoto, Kenji [Department of Radiation Oncology, Yamagata University, Yamagata (Japan); Nishimura, Yasumasa [Department of Radiation Oncology, Kinki University Faculty of Medicine, Osaka (Japan)

    2014-07-15

    Purpose: To determine whether adding intraluminal brachytherapy (ILBT) to definitive radiation therapy (RT) for unresectable biliary tract cancer has a positive impact on survival outcome. Methods and Materials: The original cohort comprised 209 patients, including 153 who underwent external beam RT (EBRT) alone and 56 who received both ILBT and EBRT. By matching propensity scores, 56 pairs (112 patients) consisting of 1 patient with and 1 patient without ILBT were selected. They were well balanced in terms of sex, age, performance status, clinical stage, jaundice, and addition of chemotherapy. The impact of ILBT on overall survival (OS), disease-specific survival (DSS), and local control (LC) was investigated. Results: The 2-year OS rates were 31% for the ILBT+ group and 40% for theILBT– group (P=.862). The 2-year DSS rates were 42% for the ILBT+ group and 41% for the ILBT– group (P=.288). The 2-year LC rates were 65% for the ILBT+ group and 35% for the ILBT– group (P=.094). Three of the 4 sensitivity analyses showed a significantly better LC for the ILBT+ group (P=.010, .025, .049), and another showed a marginally better LC (P=.068), and none of the sensitivity analyses showed any statistically significant differences in OS or DSS. Conclusions: In the treatment for unresectable biliary tract cancer, the addition of ILBT to RT has no impact on OS or DSS but is associated with better LC. Therefore, the role of ILBT should be addressed by other measures than survival benefit, for example, by less toxicity, prolonged biliary tract patency decreasing the need for further palliative interventions, or patient quality of life.

  12. Impact of Intraluminal Brachytherapy on Survival Outcome for Radiation Therapy for Unresectable Biliary Tract Cancer: A Propensity-Score Matched-Pair Analysis

    International Nuclear Information System (INIS)

    Yoshioka, Yasuo; Ogawa, Kazuhiko; Oikawa, Hirobumi; Onishi, Hiroshi; Kanesaka, Naoto; Tamamoto, Tetsuro; Kosugi, Takashi; Hatano, Kazuo; Kobayashi, Masao; Ito, Yoshinori; Takayama, Makoto; Takemoto, Mitsuhiro; Karasawa, Katsuyuki; Nagakura, Hisayasu; Imai, Michiko; Kosaka, Yasuhiro; Yamazaki, Hideya; Isohashi, Fumiaki; Nemoto, Kenji; Nishimura, Yasumasa

    2014-01-01

    Purpose: To determine whether adding intraluminal brachytherapy (ILBT) to definitive radiation therapy (RT) for unresectable biliary tract cancer has a positive impact on survival outcome. Methods and Materials: The original cohort comprised 209 patients, including 153 who underwent external beam RT (EBRT) alone and 56 who received both ILBT and EBRT. By matching propensity scores, 56 pairs (112 patients) consisting of 1 patient with and 1 patient without ILBT were selected. They were well balanced in terms of sex, age, performance status, clinical stage, jaundice, and addition of chemotherapy. The impact of ILBT on overall survival (OS), disease-specific survival (DSS), and local control (LC) was investigated. Results: The 2-year OS rates were 31% for the ILBT+ group and 40% for theILBT– group (P=.862). The 2-year DSS rates were 42% for the ILBT+ group and 41% for the ILBT– group (P=.288). The 2-year LC rates were 65% for the ILBT+ group and 35% for the ILBT– group (P=.094). Three of the 4 sensitivity analyses showed a significantly better LC for the ILBT+ group (P=.010, .025, .049), and another showed a marginally better LC (P=.068), and none of the sensitivity analyses showed any statistically significant differences in OS or DSS. Conclusions: In the treatment for unresectable biliary tract cancer, the addition of ILBT to RT has no impact on OS or DSS but is associated with better LC. Therefore, the role of ILBT should be addressed by other measures than survival benefit, for example, by less toxicity, prolonged biliary tract patency decreasing the need for further palliative interventions, or patient quality of life

  13. Appendicitis with Intraluminal Air

    International Nuclear Information System (INIS)

    Fernandez, Alfredo; Ramirez, Sandra M; Rodriguez, Cesar A; Uriza, Luis F

    2010-01-01

    The presentation of acute appendicitis with intraluminal air is an uncommon presentation. Ultrasound is a widely used and accepted to establish the diagnosis of appendicitis, but its performance is limited in situations where there is interposition of air. Inflamed appendix which presents with distension by gas can be source of error in ultrasound to establish a false negative diagnosis. In this article we present three patients with appendicitis where the interposition of intraluminal air hid their diagnostic by ultrasound. In all three cases the definitive diagnosis was established by computed tomography and surgical confirmation.

  14. 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

  15. 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

  16. 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.

  17. Randomized clinical trial of biodegradeable intraluminal sheath to prevent anastomotic leak after stapled colorectal anastomosis

    NARCIS (Netherlands)

    Bakker, I S; Morks, A N; Ten Cate Hoedemaker, H O; Burgerhof, J G M; Leuvenink, H G; van Praagh, J B; Ploeg, R J; Havenga, K

    Background: Anastomotic leakage is a potential major complication after colorectal surgery. The C-seal was developed to help reduce the clinical leakage rate. It is an intraluminal sheath that is stapled proximal to a colorectal anastomosis, covering it intraluminally and thus preventing intestinal

  18. Clinical study of suppository delivery of 5-fluorouracil and pathological effects on metastatic lymph nodes caused by preoperative combined treatment with radiation, intraluminal hyperthermia and 5-fluorouracil suppository in rectal cancer

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    Tamura, Takaaki [Kyoto Prefectural Univ. of Medicine (Japan)

    1997-11-01

    Preoperative combined treatment with radiation, intraluminal hyperthermia, and 5-fluorouracil (5-FU) suppository has been reported effective in shrinking locally advanced rectal cancers and facilitating subsequent surgery. Suppository and intravenous 5-FU administration were compared with respect to tissue concentrations in rectal cancer cases. Just before the operation patients received 100 mg of 5-FU via suppository or intravenously. Portal and systemic blood, tumor tissue, normal mucosa and muscle layer separately at 5, 10, 15 cm in the oral direction from the tumor and the pararectal lymph node were harvested for high-performance liquid chromatography determination of 5-FU concentrations. Rectal 5-FU concentrations were significantly higher in the suppository cases compared with the intravenously administrated ones. Suppository distributed more 5-FU at pararectal lymph nodes than intravenous injection. This fact revealed 5-FU suppositories to be a useful drug delivery system for rectal cancer. The pathological effects on metastatic lymph nodes caused by combined treatment were evaluated in 22 cases. Normal lymph nodes showed congestion only. Fibrotic and necrotic changes were characteristic of damaged metastatic areas. In 6 cases (27.3%), no metastatic cells were detected on fibrotically changed areas. The down staging of the lymph node metastatic factor was carried out by preoperative combined treatment. High concentrations of 5-FU at mucosa could suggest the usefulness of 5-FU suppository administration just before operation for prevention of suture-line implantation. (author)

  19. Clinical study of suppository delivery of 5-fluorouracil and pathological effects on metastatic lymph nodes caused by preoperative combined treatment with radiation, intraluminal hyperthermia and 5-fluorouracil suppository in rectal cancer

    International Nuclear Information System (INIS)

    Tamura, Takaaki

    1997-01-01

    Preoperative combined treatment with radiation, intraluminal hyperthermia, and 5-fluorouracil (5-FU) suppository has been reported effective in shrinking locally advanced rectal cancers and facilitating subsequent surgery. Suppository and intravenous 5-FU administration were compared with respect to tissue concentrations in rectal cancer cases. Just before the operation patients received 100 mg of 5-FU via suppository or intravenously. Portal and systemic blood, tumor tissue, normal mucosa and muscle layer separately at 5, 10, 15 cm in the oral direction from the tumor and the pararectal lymph node were harvested for high-performance liquid chromatography determination of 5-FU concentrations. Rectal 5-FU concentrations were significantly higher in the suppository cases compared with the intravenously administrated ones. Suppository distributed more 5-FU at pararectal lymph nodes than intravenous injection. This fact revealed 5-FU suppositories to be a useful drug delivery system for rectal cancer. The pathological effects on metastatic lymph nodes caused by combined treatment were evaluated in 22 cases. Normal lymph nodes showed congestion only. Fibrotic and necrotic changes were characteristic of damaged metastatic areas. In 6 cases (27.3%), no metastatic cells were detected on fibrotically changed areas. The down staging of the lymph node metastatic factor was carried out by preoperative combined treatment. High concentrations of 5-FU at mucosa could suggest the usefulness of 5-FU suppository administration just before operation for prevention of suture-line implantation. (author)

  20. Magnetic resonance imaging of the intraluminal thrombus in abdominal aortic aneurysms. A quantitative and qualitative evaluation and correlation with growth rate

    DEFF Research Database (Denmark)

    Behr-Rasmussen, Carsten; Gammelgaard, Lise; Fründ, Ernst T

    2017-01-01

    of four morphological categories based on visual appearance and signal intensity on T2 weighted images. RESULTS: The mean growth rate was 1.95 mm/year ± 0.87 (SD). The observation time was 5.59 ± 0.63 (SD) years. ILT was present in AAA size groups as follows: 30-34.9 mm 20.00%, 35-39.9 mm 88.89%, 40...

  1. 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

  2. Sutureless choledochoduodenostomy with an intraluminal degradable stent in dog model

    Institute of Scientific and Technical Information of China (English)

    ZHU Ling-hua; LIANG Xiao; LIN Hui; WANG Yi-fan; ZHU Yi-ping; CAI Xiu-jun

    2011-01-01

    Background It is difficult and time-consuming for carrying out conventional hand-sewn bilioenteric anastomosis, especially for small bile duct anastomosis and laparoscopic procedure. In order to simplify it, we have developed a novel procedure of sutureless bilioenteric anastomosis with an intraluminal degradable stent. This study aimed to evaluate the feasibility and safety of this technique with cholangioduodenostomy in dog model.Methods A patent intraluminal degradable stent tube for sutureless choledochoduodenostomy in dog model was made with polylactic acid in diameter of 3 mm or 4 mm. Thirty-eight dogs were randomly divided into to a stent group (SG, n=20) and a control group (CG, n=18). Dogs in the SG underwent sutureless choledochoduodenostomy with intraluminal stent, while the CG underwent conventional choledochoduodenostomy (single layer discontinuous anastomosis with absorbable suture). Dogs of each group were divided into 4 subgroups according to time of death (1,3,6, and 12 months postoperatively) to evaluate the healing of anastomosis. Operation time, intraoperative tolerance pressure of anastomosis, rate of postoperative bile leakage, bursting pressure of anastomosis were compared between the two groups. Anastomosis tissue was observed afterwards by pathology evaluation, hydroxyproline content, serum bilirubin, liver enzyme level and magnetic resonance cholangio-pancreatography (MRCP) to assess the stricture.Results All procedures were completed successfully. The surgical time of the SG was significantly less than the CG (SG: (19.2±4.3) minutes, vs. CG: (29.2±7.1) minutes, P=0.000). One bile leakage was occurred in either group. No significant difference of intraoperative tolerance pressure of anastomosis, rate of bile leakage and postoperative bursting pressure of anastomosis, anastomotic stricture, hydroxyproline content, serum bilirubin and liver enzyme level was found between the two groups. MRCP showed no anastomosis stricture and obstruction

  3. INES rating of radiation protection related events

    International Nuclear Information System (INIS)

    Hort, M.

    2009-01-01

    In this presentation, based on the draft Manual, a short review of the use of the INES rating of events concerning radiation protection is given, based on a new INES User's Manual edition. The presentation comprises a brief history of the scale development, general description of the scale and the main principles of the INES rating. Several examples of the use of the scale for radiation protection related events are mentioned. In the presentation, the term 'radiation protection related events' is used for radiation source and transport related events outside the nuclear installations. (authors)

  4. Ionizing radiation decreases human cancer mortality rates

    International Nuclear Information System (INIS)

    Luckey, T.D.

    1997-01-01

    Information from nine studies with exposed nuclear workers and military observers of atmospheric bomb explosions confirms the results from animal studies which showed that low doses of ionizing radiation are beneficial. The usual ''healthy worker effect'' was eliminated by using carefully selected control populations. The results from 13 million person-years show the cancer mortality rate of exposed persons is only 65.6% that of carefully selected unexposed controls. This overwhelming evidence makes it politically untenable and morally wrong to withhold public health benefits of low dose irradiation. Safe supplementation of ionizing radiation should become a public health service. (author)

  5. 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.

  6. Inhibition of early AAA formation by aortic intraluminal pentagalloyl glucose (PGG) infusion in a novel porcine AAA model

    DEFF Research Database (Denmark)

    Kloster, Brian O; Lund, Lars; Lindholt, Jes S

    2016-01-01

    to prevent or delay their expansion. In this study, we investigated whether intraluminal delivered pentagalloyl glucose (PGG) can impair the early AAA development in a porcine model. METHODS: The infrarenal aorta was exposed in thirty pigs. Twenty underwent an elastase based AAA inducing procedure and ten...... of these received an additional intraluminal PGG infusion. The final 10 were sham operated and served as controls. RESULTS: All pigs who only had an elastase infusion developed macroscopically expanding AAAs. In pigs treated with an additional PGG infusion the growth rate of the AP-diameter rapidly returned...... and histology. CONCLUSION: In our model, intraluminal delivered PGG is able to penetrate the aortic wall from the inside and impair the early AAA development by stabilizing the elastic lamellae and preserving their integrity. The principle holds a high clinical potential if it can be translated to human...

  7. Intra-luminal brachytherapy of bile duct tumors

    International Nuclear Information System (INIS)

    Udaya Kumar Maiya, M.; Bhat, Naresh; Praveen, L.S.

    2000-01-01

    The objective of this study has been to assess the feasibility of intraluminal brachytherapy of the biliary ductal system. The technique of the procedure with its attendant problems and how to overcome the same will be discussed in detail

  8. Anesthetic and Airways Management of a Dog with Severe Tracheal Collapse during Intraluminal Stent Placement

    Directory of Open Access Journals (Sweden)

    M. Argano

    2013-01-01

    Full Text Available This case report describes the anesthetic and airways management of a dog affected by 4th degree tracheal collapse and undergoing endoscope-guided intraluminal stent placement. After premedication with acepromazine and butorphanol, general anesthesia was induced with propofol and maintained with intravenous propofol and butorphanol in constant rate infusion. During intraluminal stent placement, oxygen was supplemented by means of a simple and inexpensive handmade device, namely, a ureteral catheter inserted into the trachea and connected to an oxygen source, which allowed for the maintenance of airways’ patency and adequate patient’s oxygenation, without decreasing visibility in the surgical field or interfering with the procedure. The use of the technique described in the present paper was the main determinant of the successful anesthetic management and may be proposed for similar critical cases in which surgical manipulation of the tracheal lumen, which may potentially result in hypoxia by compromising airways patency, is required.

  9. 192Ir Intraluminal brachytherapy for the prevention of urethral re-stricture

    International Nuclear Information System (INIS)

    Ma Changuo; Guo Hui; Du Chun; Yang Keqiang

    2008-01-01

    Objective: To evaluate the safety and efficacy of 192 Ir intraluminal brachytherapy for the prevention of urethral restricture after transurethral incision or transurethral resection of scar. Methods: From Mar. 2004 to Jun. 2006, 48 patients aging 18-81 years were treated by 192 Ir intraluminal brachytherapy. The length of stricture(0.5-5.5 cm) was ≤3.0 cm in 90% of the patients. The stricture was caused by trauma in 23 patients and prostate hyperplasia operation in 19 patients. The cause of remaining 6 patients was unclear. All patients were diagnosed by urethra photograph or endoscopy. Radiotherapy was the initial treatment in 26 patients and the second time treatment in 22. The irradiation dose was from 14 Gy to 18 Gy. Results: The median follow up was 10 months, and the total response rate was 98%. Only one patient recurred and received transurethral incision again. The uresis was fluency in 47 patients and the maximum flow rate was 13.9-36.4 (19.2 ± 10.3) ml/s. No secondary urethral bleeding or urethral cancer was observed. Conclusions: Being a safe and feasible treatment, 192 Ir intraluminal brachytherapy following transurethral incision or transurethral resection of scar can effectively prevent urethral re-stricture. (authors)

  10. 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.

  11. Intraluminal milrinone for dilation of the radial artery graft.

    Science.gov (United States)

    García-Rinaldi, R; Soltero, E R; Carballido, J; Mojica, J

    1999-01-01

    There is renewed interest in the use of the radial artery as a conduit for coronary artery bypass surgery. The radial artery is, however, a very muscular artery, prone to vasospasm. Milrinone, a potent vasodilator, has demonstrated vasodilatory properties superior to those of papaverine. In this report, we describe our technique of radial artery harvesting and the adjunctive use of intraluminal milrinone as a vasodilator in the preparation of this conduit for coronary artery bypass grafting. We have used these techniques in 25 patients who have undergone coronary artery bypass grafting using the radial artery. No hand ischemic complications have been observed in this group. Intraluminal milrinone appears to dilate and relax the radial artery, rendering this large conduit spasm free and very easy to use. We recommend the skeletonization technique for radial artery harvesting and the use of intraluminal milrinone as a radial artery vasodilator in routine myocardial revascularization. PMID:10524740

  12. Preoperative intraluminal irradiation of the extrahepatic bile duct tumor

    International Nuclear Information System (INIS)

    Kamada, Tadashi; Tsujii, Hirohiko; Arimoto, Takuro; Irie, Goro.

    1991-01-01

    From 1984 through 1986, six patients with extrahepatic bile duct tumor were treated preoperatively with intraluminal irradiation of the bile duct. There were no unresectable cases and pathological examination of the surgical specimens showed moderate to remarkable tumor regression in all cases. Postoperative biliary tract hemorrhage occurred in 2 of 3 patients who received 60 Gy at a point 7.5 mm from the center of the source. With accurate preoperative diagnosis of the tumor extent and careful setting of the target area of intraluminal irradiation, improved local tumor control of extrahepatic bile duct tumor can be expected with this method. (author)

  13. 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.)

  14. 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.

  15. Radiative decay rates in Si crystallites with a donor ion

    Science.gov (United States)

    Derbenyova, Natalia V.; Burdov, Vladimir A.

    2018-04-01

    Within the framework of the time-dependent density functional theory, the radiative recombination rates have been calculated for small, ˜1 nm in diameter, hydrogen-passivated silicon crystallites with a single lithium or phosphorus ion. Sharp increase of the radiative recombination rates with increasing temperature was revealed for the crystallites with the lithium ion. No temperature effect was found for the crystallites with the ion of P. It was also shown that the presence of ionized donors in Si crystallites can substantially accelerate the radiative decay compared to the case of pure crystallites.

  16. Esophageal acid exposure decreases intraluminal baseline impedance levels

    NARCIS (Netherlands)

    Kessing, Boudewijn F.; Bredenoord, Albert J.; Weijenborg, Pim W.; Hemmink, Gerrit J. M.; Loots, Clara M.; Smout, A. J. P. M.

    2011-01-01

    Intraluminal baseline impedance levels are determined by the conductivity of the esophageal wall and can be decreased in gastroesophageal reflux disease (GERD) patients. The aim of this study was to investigate the baseline impedance in GERD patients, on and off proton pump inhibitor (PPI), and in

  17. 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)

  18. Intraluminal Radioactive Stent Compared with Covered Stent Alone for the Treatment of Malignant Esophageal Stricture

    International Nuclear Information System (INIS)

    Wang Zhongmin; Huang Xunbo; Cao Jun; Huang Gang; Chen Kemin; LIu Yu; Liu Fenju

    2012-01-01

    Objective: This study was designed to compare the clinical effectiveness of intraluminal radioactive stent loaded with iodine-125 seeds implantation versus covered stent alone insertion in patients with malignant esophageal stricture. Methods: We studied two groups of patients with malignant esophageal stricture. Group A comprised 28 patients (19 men and 9 women) who underwent intraluminal radioactive stent loaded with iodine-125 seeds implantation and were followed prospectively. Group B comprised 30 patients (18 men and 12 women) who had previously received covered stent alone insertion; these patients were evaluated retrospectively. There was no crossover between the two groups during follow-up. Informed consent was obtained from each patient, and our institutional review board approved the study. The dysphagia score, overall survival rates, complication rates, and reintervention rates were compared in the two groups. Results: There were no significant differences between the two groups in terms of baseline characteristics. Stent placement was technically successful and well tolerated in all patients. The dysphagia score was improved in both groups after stent placement. The median survival was significantly longer in group A than in group B: 11 versus 4.9 months, respectively (P < 0.001). The complications of chest pain, esophageal reflux, and stent migration was more frequent in group B, but this difference did not reach statistical significance. There was no statistical difference in reintervention between two groups. Conclusions: Intraluminal radioactive stent loaded with iodine-125 seeds implantation was a feasible and practical management in treating malignant esophageal stricture and was superior to covered stent alone insertion, as measured by survival.

  19. Elevated Rate of Genome Rearrangements in Radiation-Resistant Bacteria.

    Science.gov (United States)

    Repar, Jelena; Supek, Fran; Klanjscek, Tin; Warnecke, Tobias; Zahradka, Ksenija; Zahradka, Davor

    2017-04-01

    A number of bacterial, archaeal, and eukaryotic species are known for their resistance to ionizing radiation. One of the challenges these species face is a potent environmental source of DNA double-strand breaks, potential drivers of genome structure evolution. Efficient and accurate DNA double-strand break repair systems have been demonstrated in several unrelated radiation-resistant species and are putative adaptations to the DNA damaging environment. Such adaptations are expected to compensate for the genome-destabilizing effect of environmental DNA damage and may be expected to result in a more conserved gene order in radiation-resistant species. However, here we show that rates of genome rearrangements, measured as loss of gene order conservation with time, are higher in radiation-resistant species in multiple, phylogenetically independent groups of bacteria. Comparison of indicators of selection for genome organization between radiation-resistant and phylogenetically matched, nonresistant species argues against tolerance to disruption of genome structure as a strategy for radiation resistance. Interestingly, an important mechanism affecting genome rearrangements in prokaryotes, the symmetrical inversions around the origin of DNA replication, shapes genome structure of both radiation-resistant and nonresistant species. In conclusion, the opposing effects of environmental DNA damage and DNA repair result in elevated rates of genome rearrangements in radiation-resistant bacteria. Copyright © 2017 Repar et al.

  20. Radiation safety program in a high dose rate brachytherapy facility

    International Nuclear Information System (INIS)

    Rodriguez, L.V.; Hermoso, T.M.; Solis, R.C.

    2001-01-01

    The use of remote afterloading equipment has been developed to improve radiation safety in the delivery of treatment in brachytherapy. Several accidents, however, have been reported involving high dose-rate brachytherapy system. These events, together with the desire to address the concerns of radiation workers, and the anticipated adoption of the International Basic Safety Standards for Protection Against Ionizing Radiation (IAEA, 1996), led to the development of the radiation safety program at the Department of Radiotherapy, Jose R. Reyes Memorial Medical Center and at the Division of Radiation Oncology, St. Luke's Medical Center. The radiation safety program covers five major aspects: quality control/quality assurance, radiation monitoring, preventive maintenance, administrative measures and quality audit. Measures for evaluation of effectiveness of the program include decreased unnecessary exposures of patients and staff, improved accuracy in treatment delivery and increased department efficiency due to the development of staff vigilance and decreased anxiety. The success in the implementation required the participation and cooperation of all the personnel involved in the procedures and strong management support. This paper will discuss the radiation safety program for a high dose rate brachytherapy facility developed at these two institutes which may serve as a guideline for other hospitals intending to install a similar facility. (author)

  1. 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)

  2. 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.)

  3. Information rates of radiation as a photon gas

    NARCIS (Netherlands)

    Martinez, A.

    2008-01-01

    The information rates achievable with a photon-gas model of electromagnetic radiation are studied. At any frequency, information rates over the photon-gas model essentially coincide with the Shannon capacity when the signal-to-noise ratio is below a threshold. Only above the threshold does the

  4. 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)

  5. Problems of dose rate in radiation protection regulation

    International Nuclear Information System (INIS)

    Osmachkin, V.S.

    2001-01-01

    Some modern problems of Radiation Safety Standards are discussed. It is known that Standards are based on the Linear-Non-Threshold Concept (LNTC) of radiation risk, which is now called by many experts as conservative. It is thought it is necessary to include in the Standards such factor as dose rate or duration of irradiation. Some model of effects of radiation exposure with taking into account the reparation of cell damage is presented. The practical method for assessment of effects of duration of irradiation on detriments is proposed.(author)

  6. 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

  7. Strong effects of ionizing radiation from Chernobyl on mutation rates

    OpenAIRE

    M?ller, Anders Pape; Mousseau, Timothy A.

    2015-01-01

    In this paper we use a meta-analysis to examine the relationship between radiation and mutation rates in Chernobyl across 45 published studies, covering 30 species. Overall effect size of radiation on mutation rates estimated as Pearson's product-moment correlation coefficient was very large (E = 0.67; 95% confidence intervals (CI) 0.59 to 0.73), accounting for 44.3% of the total variance in an unstructured random-effects model. Fail-safe calculations reflecting the number of unpublished null...

  8. 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.)

  9. Dose rate effectiveness in radiation-induced teratogenesis in mice

    International Nuclear Information System (INIS)

    Kato, F.; Ootsuyama, A.; Norimura, T.

    2000-01-01

    To investigate the role of p53 gene in tissue repair of teratogenic injury, we compared incidence of radiation-induced malformations in homozygous p53(-/-) mice, heterozygous p53(+/-) mice and wild-type p53(+/+) mice. After X-irradiation with 2 Gy at high dose rate on 9.5 days of gestation, p53(-/-) mice showed higher incidences of anomalies and higher resistance to prenatal deaths than p53(+/+) mice. This reciprocal relationship of radiosensitivity to anomalies and deaths supports the notion that embryos or fetuses have a p53-dependent 'guardian' that aborts cells bearing radiation-induced teratogenic DNA damage. In fact, after X-irradiation, the number of apoptotic cells was greatly increased in p53(+/+) fetuses but not in p53(-/-) fetuses. The same dose of γ-ray exposure at low dose rate on 9.5-10.5 day of gestation produced significant reduction of radiation-induced malformation in p53(+/+) and p53(+/-) mice, remained teratogenic for p53(-/-) mice. These results suggest that complete elimination of teratogenic damage from irradiated tissues requires the concerted cooperation of two mechanisms; proficient DNA repair and the p53-dependent apoptotic tissue repair. When concerted DNA repair and apoptosis functions efficiently, there is a threshold dose-rate for radiation-induced malformations. (author)

  10. 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.

  11. Prototype Operational Advances for Atmospheric Radiation Dose Rate Specification

    Science.gov (United States)

    Tobiska, W. K.; Bouwer, D.; Bailey, J. J.; Didkovsky, L. V.; Judge, K.; Garrett, H. B.; Atwell, W.; Gersey, B.; Wilkins, R.; Rice, D.; Schunk, R. W.; Bell, D.; Mertens, C. J.; Xu, X.; Crowley, G.; Reynolds, A.; Azeem, I.; Wiltberger, M. J.; Wiley, S.; Bacon, S.; Teets, E.; Sim, A.; Dominik, L.

    2014-12-01

    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. 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 developed innovative, new space weather observations that will become part of the toolset that is transitioned into operational use. One prototype operational system for providing timely information about the effects of space weather is SET's Automated Radiation Measurements for Aerospace Safety (ARMAS) system. ARMAS will provide the "weather" of the radiation environment to improve aircraft crew and passenger safety. Through several dozen flights the ARMAS project has 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 via Iridium satellites, 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. We are extending the dose measurement domain above commercial aviation altitudes into the stratosphere with a collaborative project organized by NASA's Armstrong Flight Research Center (AFRC) called Upper-atmospheric Space and Earth Weather eXperiment (USEWX). In USEWX we will be flying on the ER-2 high altitude aircraft a micro dosimeter for

  12. L-shell radiative transition rates by selective synchrotron ionization

    International Nuclear Information System (INIS)

    Bonetto, R D; Carreras, A C; Trincavelli, J; Castellano, G

    2004-01-01

    Relative L-shell radiative transition rates were obtained for a number of decays in Gd, Dy, Er, Yb, Hf, Ta and Re by means of a method for refining atomic and experimental parameters involved in the spectral analysis of x-ray irradiated samples. For this purpose, pure samples were bombarded with monochromatic synchrotron radiation tuning the incident x-ray energy in order to allow selective ionization of the different atomic shells. The results presented are compared to experimental and theoretical values published by other authors. A good general agreement was found and some particular discrepancies are discussed

  13. 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)

  14. Radiation damage and rate limitations in tracking devices

    International Nuclear Information System (INIS)

    Gilchriese, M.G.D.

    1984-01-01

    In this note the author briefly discusses radiation damage to wire chambers and silicon strip devices and the electronics that may be associated with each of these. Scintillating fibers and CCD's are not discussed although the former appears to be a potentially radiation-resistant detector. In order to calculate radiation levels and rates the author assumed the following: an inelastic cross section of 100 mb at the SSC - six charged particles per unit of rapidity - photons and neutrons do not contribute to the background (photon conversions are negligible with a thin Be beam pipe) - beam gas interactions and beam losses (except during injection when I assume that the detector is ''off'') are negligible. This is discussed in a later section. - 1 Rad = 3.5 x 10 7 minimum ionizing particlescm 2

  15. Strong effects of ionizing radiation from Chernobyl on mutation rates.

    Science.gov (United States)

    Møller, Anders Pape; Mousseau, Timothy A

    2015-02-10

    In this paper we use a meta-analysis to examine the relationship between radiation and mutation rates in Chernobyl across 45 published studies, covering 30 species. Overall effect size of radiation on mutation rates estimated as Pearson's product-moment correlation coefficient was very large (E = 0.67; 95% confidence intervals (CI) 0.59 to 0.73), accounting for 44.3% of the total variance in an unstructured random-effects model. Fail-safe calculations reflecting the number of unpublished null results needed to eliminate this average effect size showed the extreme robustness of this finding (Rosenberg's method: 4135 at p = 0.05). Indirect tests did not provide any evidence of publication bias. The effect of radiation on mutations varied among taxa, with plants showing a larger effect than animals. Humans were shown to have intermediate sensitivity of mutations to radiation compared to other species. Effect size did not decrease over time, providing no evidence for an improvement in environmental conditions. The surprisingly high mean effect size suggests a strong impact of radioactive contamination on individual fitness in current and future generations, with potentially significant population-level consequences, even beyond the area contaminated with radioactive material.

  16. [The role of colonoscopy in early diagnosis of intraluminal recurrences in patients already treated for colorectal cancer].

    Science.gov (United States)

    Barillari, P; Manetti, G; Bovino, A; Puce, Y; Piovanello, P; Cioè, I; Sammartino, P; Stipa, V

    1996-11-01

    It is a common opinion that the more often and the more rigorously the colon is examined, the more lesions will be discovered and diagnosed. However it has not been shown which methods of colonic examination and which regimen of surveillance should be used. Chart review was conducted on 481 patients who underwent curative resection for colorectal cancer between 1980 and 1990. Colonoscopy was performed preoperatively, after 12-15 months from surgical treatment, and then at an interval of 12-24 months, or when symptoms appeared. About ten percent of patients developed intraluminal recurrences, and more than 25% adenomatous polyps. More than one half of the metachronous lesions arise within the first 24 months. The median time to diagnosis was 25 months for intraluminal recurrences and 22 months for adenomatous polyps. Patients with left sited tumor at an advanced stage run a higher risk of developing recurrent intraluminal disease, and patients who presented associated polyps at the time of the operation for the index cancer have a higher risk of developing new polyps. About 50% of recurrences were detected when patients were asymptomatic. Colonoscopy must be performed within the first 12-15 months after operation, while an interval of 24 months between each examination seems sufficient to guarantee an early detection of metachronous lesion. Asymptomatic patients are more frequently reoperated for cure and thus have a better survival rate.

  17. Inhibition of early AAA formation by aortic intraluminal pentagalloyl glucose (PGG) infusion in a novel porcine AAA model.

    Science.gov (United States)

    Kloster, Brian O; Lund, Lars; Lindholt, Jes S

    2016-05-01

    The vast majority of abdominal aortic aneurysms found in screening programs are small, and as no effective treatment exits, many will expand until surgery is indicated. Therefore, it remains intriguing to develop a safe and low cost treatment of these small aneurysms, that is able to prevent or delay their expansion. In this study, we investigated whether intraluminal delivered pentagalloyl glucose (PGG) can impair the early AAA development in a porcine model. The infrarenal aorta was exposed in thirty pigs. Twenty underwent an elastase based AAA inducing procedure and ten of these received an additional intraluminal PGG infusion. The final 10 were sham operated and served as controls. All pigs who only had an elastase infusion developed macroscopically expanding AAAs. In pigs treated with an additional PGG infusion the growth rate of the AP-diameter rapidly returned to physiological values as seen in the control group. In the elastase group, histology revealed more or less complete resolution of the elastic lamellae in the media while they were more abundant, coherent and structurally organized in the PGG group. The control group displayed normal physiological growth and histology. In our model, intraluminal delivered PGG is able to penetrate the aortic wall from the inside and impair the early AAA development by stabilizing the elastic lamellae and preserving their integrity. The principle holds a high clinical potential if it can be translated to human conditions, since it, if so, potentially could represent a new drug for stabilizing small abdominal aneurysms.

  18. 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)

  19. 106Ru and 125I radiation dose rate gauge

    International Nuclear Information System (INIS)

    Machaj, B.; Swistowski, E.; Do Hoang Cuong

    2002-01-01

    Pulse count rate from plastic scintillator is a measure of the dose rate. Low dead time of measured channel and digital processing of measuring head signal with compensation of dead time enables correct registration of very high pulse count rate. The radiation source is set with an accuracy not worse than 0.1 mm in relation to the scintillator, and the movement of the source in horizontal and vertical direction is done with the accuracy of 0.01 mm. Additionally the gauge permits to measure the source activity and to check the uniform distribution of the radioactive material on the source surface. Random error due to pulse count rate fluctuation is negligible. The error due to instability of PTM gain is approx. 1,5% for 106 Ru and 5% for 125 I. (author)

  20. Nylon filament coated with paraffin for intraluminal permanent middle cerebral artery occlusion in rats.

    Science.gov (United States)

    Zuo, Xia-Lin; Wu, Ping; Ji, Ai-Min

    2012-06-21

    A variety of intraluminal nylon filament has been used in rat middle cerebral artery occlusion (MCAO) models. However the lesion extent and its reproducibility vary among laboratories. The properties of nylon filament play a part of reasons for these variations. In the present study, we used paraffin-coated nylon filament for rat MCAO model, tested the effects and advanced improvement for making the rat MCAO. Forty male Sprague-Dawley (SD) rats were randomized into two groups, MCAO with traditional uncoated nylon filament (uMCAO) and MCAO with paraffin-coated nylon filament (cMCAO), three rats as normal group and sham group respectively. Assessment included mortality rates, model success rates, neurological deficit evaluation, and infarct volume. The study showed two rats died in uMCAO group, no rat died in cMCAO group within the 12h. The model success rate of uMCAO was 100%, while the uMCAO group was 55% (n=20, two died within 12h, seven rats were excluded as the brain slices showed no TTC staining due to subarachanoid hemorrhage). Neurological evaluation demonstrated group cMCAO had more worse neurological outcomes than group uMCAO, and the difference was statistically signification (pparaffin-coated nylon filament intraluminal occlusion provide better occlusion of middle cerebral artery than the uncoated nylon filament, improve the consistent of model, and raise the success rate to reduce the number of experimental animals. These positive results are much encouraging and interesting. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  1. Portable radiation meters evaluation in high rates of air kerma

    International Nuclear Information System (INIS)

    Damatto, Willian B.; Potiens, Maria da Penha A.; Vivolo, Vitor

    2015-01-01

    A set of portable meters of ionizing radiation high rates of air kerma (teletectors) commonly used in emergencies in Brazil and sent to the Calibration Laboratory of IPEN were under several tests and analyst is parameters for the detectors behavior were established, specifying their sensitivities and operating characteristics. Applied tests were: reading equipment variation with battery voltage, geotropism effect, energy dependence, the angular dependence and overload. Thus it was possible to determine the most common characteristic found in these equipment (quality control programs). The behavior of 17 portable meters was analyzed and in this study, 10 of them have been tested. It was performed to characterize the gamma irradiating system (radiation dosimetry field) that possesses higher activity in teletectors for testing of larger measuring range. New calibration criteria were established following international recommendations. Therefore, it was made the improvement of the quality control programme of portable meters of ionizing radiation high rates of air kerma calibration laboratory, benefiting the users of such equipment with better consistent calibration measurements. (author)

  2. Combined external beam and intraluminal radiotherapy for irresectable Klatskin tumors

    Energy Technology Data Exchange (ETDEWEB)

    Schleicher, U.M. [Klinik fuer Strahlentherapie, Technische Hochschule Aachen (Germany); Staatz, G. [Klinik fuer Radiologische Diagnostik, Technische Hochschule Aachen (Germany); Alzen, G. [Klinik fuer Radiologische Diagnostik, Technische Hochschule Aachen (Germany); Abt. Kinderradiologie, Giessen Univ. (Germany); Andreopoulos, D. [Klinik fuer Strahlentherapie, Technische Hochschule Aachen (Germany); BOC Oncology Centre, Nikosia (Cyprus)

    2002-12-01

    Background: In most cases of proximal cholangiocarcinoma, curative surgery is not possible. Radiotherapy can be used for palliative treatment. We report our experience with combined external beam and intraluminal radiotherapy of advanced Klatskin's tumors. Patients and Methods: 30 patients were treated for extrahepatic proximal bile duct cancer. Our schedule consisted for external beam radiotherapy (median dose 30 Gy) and a high-dose-rate brachytherapy boost (median dose 40 Gy) delivered in four or five fractions, which could be applied completely in twelve of our patients. 15 patients in the brachytherapy and nine patients in the non-brachytherapy group received additional low-dose chemotherapy with 5-fluorouracil. Results: The brachytherapy boost dose improved the effect of external beam radiotherapy by increasing survival from a median of 3.9 months in the non-brachytherapy group to 9.1 months in the brachytherapy group. The effect was obvious in patients receiving a brachytherapy dose above 30 Gy, and in those without jaundice at the beginning of radiotherapy (p<0.05). Conclusions: The poor prognosis in patients with advanced Klatskin's tumors may be improved by combination therapy, with the role of brachytherapy and chemotherapy still to be defined. Our results suggest that patients without jaundice should be offered brachytherapy, and that a full dose of more than 30 Gy should be applied. (orig.) [German] Hintergrund: Bei den meisten Patienten mit proximalen Cholangiokarzinomen ist eine kurative Operation nicht mehr moeglich. Im Rahmen der Palliativbehandlung kann die Strahlentherapie eingesetzt werden. Wir berichten ueber unsere Erfahrungen mit der Kombination aus perkutaner und intraluminaler Strahlentherapie fortgeschrittener Klatskin-Tumoren. Patienten und Methode: 30 Patienten wurden wegen extrahepatischer proximaler Gallengangskarzinome behandelt. Unser Therapieschema umfasste eine perkutane Strahlentherapie (mediane Dosis: 30 Gy) sowie einen

  3. An audit of combined multichannel intraluminal impedance manometry in the assessment of dysphagia.

    Science.gov (United States)

    Burgess, Nicholas G; Wyeth, John W

    2011-04-01

    Multichannel Intraluminal Impedance (MII) Monitoring is a method of examining oesophageal bolus transit without the need for radiation. In combination with oesophageal manometry it allows correlation of bolus transit with peristaltic activity. The clinical application of impedance manometry is still being refined. This audit looked to examine whether impedance manometry had advantages over standard manometry in assessment of patients with dysphagia. 41 patients with the presenting symptom of dysphagia were assessed by combined MII and oesophageal manometry at a Wellington Hospital between February 2008 and December 2009. Each underwent manometry and MII using standardised techniques. Achalasia was diagnosed in 23 patients (56.1%), Ineffective oesophageal motility (IEM) in 5 patients (12.2%), Diffuse oesophageal Spasm (DES) in 7 patients (17.1%), and Nutcracker oesophagus in 2 patients (4.9%). 4 patients had normal manometry studies (9.8%). All patients with achalasia, IEM, and DES had abnormal bolus transit. All patients with normal manometry had abnormal bolus transit. Both patients with nutcracker oesophagus had normal bolus transit. 4 patients with achalasia had undergone previous Hellers myotomy. Two of these patients (50.0%) now had normal LES relaxation pressures, but all four still had abnormal oesophageal peristalsis and abnormal bolus transit. Multichannel Intraluminal Impedance manometry has advantages over standard manometry in characterising the physiological abnormalities associated with dysphagia. Patients in this study had severe defects including achalasia where bolus transit was invariably poor meaning little further information was gained. Extension of this study to include a wider group of patients with dysphagia may yield different results. © 2011 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd.

  4. Intraluminal proteome and peptidome of human urinary extracellular vesicles.

    Science.gov (United States)

    Liu, Xinyu; Chinello, Clizia; Musante, Luca; Cazzaniga, Marta; Tataruch, Dorota; Calzaferri, Giulio; James Smith, Andrew; De Sio, Gabriele; Magni, Fulvio; Zou, Hequn; Holthofer, Harry

    2015-06-01

    Urinary extracellular vesicles (UEVs) are a novel source for disease biomarker discovery. However, Tamm-Horsfall protein (THP) is still a challenge for proteomic analysis since it can inhibit detection of low-abundance proteins. Here, we introduce a new approach that does not involve an ultracentrifugation step to enrich vesicles and that reduces the amount of THP to manageable levels. UEVs were dialyzed and ultrafiltered after reduction and alkylation. The retained fraction was digested with trypsin to reduce the remaining THP and incubated with deoxycholate (DOC). The internal peptidome and internal proteome were analyzed by LC-ESI-MS. A total of 942 different proteins and 3115 unique endogenous peptide fragments deriving from 973 different protein isoforms were identified. Around 82% of the key endosomal sorting complex required for transport components of UEVs generation could be detected from the intraluminal content. Our UEVs preparation protocol provides a simplified way to investigate the intraluminal proteome and peptidome, in particular the subpopulation of UEVs of the trypsin-resistant class of exosomes (positive for tumor susceptibility gene101) and eliminates the majority of interfering proteins such as THP. This method allows the possibility to study endoproteome and endopeptidome of UEVs, thus greatly facilitating biomarker discovery. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Intraluminal bubble dynamics induced by lithotripsy shock wave

    Science.gov (United States)

    Song, Jie; Bai, Jiaming; Zhou, Yufeng

    2016-12-01

    Extracorporeal shock wave lithotripsy (ESWL) has been the first option in the treatment of calculi in the upper urinary tract since its introduction. ESWL-induced renal injury is also found after treatment and is assumed to associate with intraluminal bubble dynamics. To further understand the interaction of bubble expansion and collapse with the vessel wall, the finite element method (FEM) was used to simulate intraluminal bubble dynamics and calculate the distribution of stress in the vessel wall and surrounding soft tissue during cavitation. The effects of peak pressure, vessel size, and stiffness of soft tissue were investigated. Significant dilation on the vessel wall occurs after contacting with rapid and large bubble expansion, and then vessel deformation propagates in the axial direction. During bubble collapse, large shear stress is found to be applied to the vessel wall at a clinical lithotripter setting (i.e. 40 MPa peak pressure), which may be the mechanism of ESWL-induced vessel rupture. The decrease of vessel size and viscosity of soft tissue would enhance vessel deformation and, consequently, increase the generated shear stress and normal stresses. Meanwhile, a significantly asymmetric bubble boundary is also found due to faster axial bubble expansion and shrinkage than in radial direction, and deformation of the vessel wall may result in the formation of microjets in the axial direction. Therefore, this numerical work would illustrate the mechanism of ESWL-induced tissue injury in order to develop appropriate counteractive strategies for reduced adverse effects.

  6. Large Intraluminal Ileal Hematoma Presenting as Small Bowel Obstruction in a Child

    International Nuclear Information System (INIS)

    Lim, Yun Jung; Nam, So Hyun; Kim, Seon Jeong

    2015-01-01

    Intraluminal small bowel hematoma has been rarely reported in children, as a rare cause of small bowel obstruction. We present a case of an intraluminal ileal hematoma presenting as small bowel obstruction in a child. Computed Tomography (CT) indicated a large intraluminal hyperdense lesion in the distal ileum as the cause of small bowel obstruction. Abdominal ultrasonography (US) showed an echogenic mass-like lesion with multiple septa in the distal ileum. Small bowel obstruction due to a complicated cystic mass was provisionally diagnosed. Histopathologic examination of the resected mass suggested a submucosal ileal hematoma. Although intraluminal small bowel hematoma is rare in children, it can present as an intraluminal cystic mass and should be considered as a rare cause of small bowel obstruction. The US and CT findings of submucosal ileal hematoma could be useful for the diagnosis of such cases in the future

  7. Identification of intraluminal thrombus by ultrasonography in emergency department patients with acute deep venous thrombosis.

    Science.gov (United States)

    Mehta, Ninfa; Schecter, Joshua; Stone, Michael

    2012-05-01

    Traditionally, the diagnosis of deep venous thrombosis (DVT) using duplex ultrasonography (DU) has relied on the absence of venous compressibility. Visualization of an intraluminal thrombus is considered an uncommon finding. The purpose of this study is to determine the frequency of intraluminal thrombus in emergency department (ED) patients diagnosed with acute DVT. Retrospective chart review of adult ED patients with DU examinations demonstrating acute DVT. Patients with chronic DVT or patients in whom DU did not demonstrate DVT were excluded from data analysis. Study reports and ultrasound images were reviewed and analyzed for the presence of intraluminal thrombus. There were 189 patients who met inclusion criteria, of which 160 (85%) were found to have intraluminal thrombus. Intraluminal thrombi are present in the majority of patients in our ED in whom acute DVT is identified by DU. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. 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

  9. Terrestrial Gamma Radiation Dose Rate of West Sarawak

    Science.gov (United States)

    Izham, A.; Ramli, A. T.; Saridan Wan Hassan, W. M.; Idris, H. N.; Basri, N. A.

    2017-10-01

    A study of terrestrial gamma radiation (TGR) dose rate was conducted in west of Sarawak, covering Kuching, Samarahan, Serian, Sri Aman, and Betong divisions to construct a baseline TGR dose rate level data of the areas. The total area covered was 20,259.2 km2, where in-situ measurements of TGR dose rate were taken using NaI(Tl) scintillation detector Ludlum 19 micro R meter NaI(Tl) approximately 1 meter above ground level. Twenty-nine soil samples were taken across the 5 divisions covering 26 pairings of 9 geological formations and 7 soil types. A hyperpure Germanium detector was then used to find the samples' 238U, 232Th, and 40K radionuclides concentrations producing a correction factor Cf = 0.544. A total of239 measured data were corrected with Cf resulting in a mean Dm of 47 ± 1 nGy h-1, with a range between 5 nGy h-1 - 103 nGy h-1. A multiple regression analysis was conducted between geological means and soil types means against the corrected TGR dose rate Dm, generating Dg,s= 0.847Dg+ 0.637Ds- 22.313 prediction model with a normalized Beta equation of Dg,s= 0.605Dg+ 0.395Ds. The model has an 84.6% acceptance of Whitney- Mann test null hypothesis when tested against the corrected TGR dose rates.

  10. Oscillator strengths and radiative rates for transitions in neutral sulfur

    International Nuclear Information System (INIS)

    Deb, N.C.; Hibbert, A.

    2008-01-01

    We present accurate oscillator strengths and radiative rates for 2173 E1 transitions among the 120 levels belonging to 3s 2 3p 4 , 3s3p 5 , and 3s 2 3p 3 ( 4 S o , 2 D o , 2 P o )nl configurations where nl=4s,5s,6s,4p,5p,6p,3d,4d,4f,5f. A configuration interaction approach is employed through the standard CIV3 program. The 114 LS states included in the present calculation generate 250 fine-structure levels belonging to the above configurations below 100,000 cm -1 . However, results of only 120 fine-structure levels are presented due to the absence of experimental energy values for the remaining levels. Tabulations of oscillator strengths and radiative rates, and their comparison with other calculations, are presented in the first two tables. In a separate table the oscillator strengths and transition probabilities, in length and velocity gauges, are presented for 2173 E1 transitions, and are arranged in ascending order of wavelength

  11. Energy levels and radiative rates for transitions in Ti VI

    International Nuclear Information System (INIS)

    Aggarwal, K M; Keenan, F P; Msezane, A Z

    2013-01-01

    We report on calculations of energy levels, radiative rates, oscillator strengths and line strengths for transitions among the lowest 253 levels of the (1s 2 2s 2 2p 6 ) 3s 2 3p 5 , 3s3p 6 , 3s 2 3p 4 3d, 3s3p 5 3d, 3s 2 3p 3 3d 2 , 3s 2 3p 4 4s, 3s 2 3p 4 4p and 3s 2 3p 4 4d configurations of Ti VI. The general-purpose relativistic atomic structure package and flexible atomic code are adopted for the calculations. Radiative rates, oscillator strengths and line strengths are reported for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2) and magnetic quadrupole (M2) transitions among the 253 levels, although calculations have been performed for a much larger number of levels. Comparisons are made with existing available results and the accuracy of the data is assessed. Additionally, lifetimes for all 253 levels are listed, although comparisons with other theoretical results are limited to only 88 levels. Our energy levels are estimated to be accurate to better than 1% (within 0.03 Ryd), whereas results for other parameters are probably accurate to better than 20%. A reassessment of the energy level data on the National Institute of Standards and Technology website for Ti VI is suggested. (paper)

  12. Dose rate effect on material aging due to radiation. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Shin-ichi (Radiation Center of Osaka Prefecture, Sakai (Japan)); Hayakawa, Chikara; Takeya, Chikashi

    1982-12-01

    Although many reports have been presented on the radiation aging of the organic materials for electric cables, those have been based on the experiments carried out at high dose rate near 1 x 10/sup 6/ rad/h, assuming that aging effect depends on only radiation dose. Therefore, to investigate the aging behaviour in low dose rate range is an important subject to predict their practical life time. In this report, the results of having investigated the aging behaviour of six types of materials are described, (polyethylene for general insulation purpose, chemically cross-linked polyethylene, fire-retardant chemically cross-linked polyethylene, fire-retardant ethylene-propylene rubber, fire-retardant chloro-sulfonated polyethylene for sheaths, and fire-retardant, low hydrochloric acid, special heat-resistant vinyl for insulation purpose or chloroclean). They were irradiated with /sup 60/Co ..gamma..-ray at the dose from 5 x 10/sup 3/ to 1 x 10/sup 6/ rad/h, and their deterioration was tested for the items of elongation, tensile strength, resistivity, dielectric tangent and gel fraction. The aging mechanism and dose rate effect were also considered. The dose rate effect appeared or did not appear depending on the types of materials and also their properties. The materials that showed the dose rate effect included the typical ones whose characteristics degraded with the decreasing dose rate, and the peculiar ones whose deterioration of characteristics did not appear constantly. Aging mechanism may vary in the case of high dose rate and low dose rate. Also, if the life time at respective dose rate in relatively higher dose rate region is clarified, the life time in low dose rate region may possibly be predicted.

  13. Influence of degradation rate of oil on its radiation stability

    International Nuclear Information System (INIS)

    Hajiyeva, S.R.; Samadova, A.A.; Mustafayev, I.I; Guliyeva, N.K.; Melikova, S.Z.

    2015-01-01

    Regularities of radiation-chemical transformations of heavy fractions of Surakhani oil fields of Azerbaijan taken from the surface of the basin were studied. Studies were conducted at the range of absorbed doses of γ-radiation 3,8 - 109,5 kGy at dose rate of P=0,21 Gy/s. It was established radiation-chemical yields of gases obtained within the radiolysis of oil fractions and determined structural-group composition of the components. The research results will allow evaluating the possibility of applying radiation-chemical technology in purification of water from degraded oil products.In terms of negative impact on the environment, the oil industry is in one of the first places among the leading sectors of the economy. The problem of water pollution with oil and oil products are becoming more urgent each year. The last accidents (in the Gulf of Mexico, on Amur, in Azerbaijan) clearly show the need for application of new methods of water purification from oil /1/. Oil and oil products fall into the body of water in different ways: with storm water, within pipeline accidents, dumping of industrial sewage, etc. According to experts, each year about 10 million tons of oil and oil products get in the world ocean /2/. Only Azerbaijan dumps more than 500 mln m3 of normative-treated water in the Caspian Sea every year, as a result of which the sea gets more than 3 thousand tons of oil products, 25 tons of phenols, 28 thousand tons of suspended materials, 520 thousand tons of synthetic surfactant /3/. Within the ingress of oil on the surface of water objects the greatest danger is its spread to large areas, leading to disruption of ecological balance in the environment. Oil consisting of mainly hydrocarbon molecules, insoluble in water, spreads on the surface of the water during a disaster. Under the action of waves and current, the oil patch divided into many parts. Volatile fractions evaporate in the first hours of the accident; further processes occurring within the

  14. The role of radiotherapy in the management of extrahepatic bile duct cancer: an analysis of 145 consecutive patients treated with intraluminal and/or external beam radiotherapy

    International Nuclear Information System (INIS)

    Kamada, Tadashi; Saitou, Hiroya; Takamura, Akio; Nojima, Takayuki; Okushiba, Shun-Ichi

    1996-01-01

    Purpose: To determine the feasibility of high dose radiotherapy and to evaluate its role in the management of extrahepatic bile duct (EHBD) cancer. Methods and Materials: Between 1983 and 1991, 145 consecutive patients with EHBD cancer were treated by low dose rate intraluminal 192 Ir irradiation (ILRT) either alone or in combination with external beam radiotherapy (EBRT). Among the primarily irradiated, 77 patients unsuitable for surgical resection, 54 were enrolled in radical radiotherapy, and 23 received palliative radiotherapy. Fifty-nine received postoperative radiotherapy, and the remaining 9 preoperative radiotherapy. The mean radiation dose was 67.8 Gy, ranging from 10 to 135 Gy. Intraluminal 192 Ir irradiation was indicated in 103 patients, and 85 of them were combined with EBRT. Expandable metallic biliary endoprosthesis (EMBE) was used in 32 primarily irradiated patients (31 radical and 1 palliative radiotherapy) after the completion of radiotherapy. Results: The 1-, 3-, and 5-year actuarial survival rates for all 145 patients were 55%, 18%, and 10%, for the 54 patients treated by radical radiotherapy (mean 83.1 Gy), 56%, 13%, and 6% [median survival time (MST) 12.4 months], and for the 59 patients receiving postoperative radiotherapy (mean 61.6 Gy), 73%, 31%, and 18% (MST 21.5 months), respectively. Expandable metallic biliary endoprosthesis was useful for the early establishment of an internal bile passage in radically irradiated patients and MST of 14.9 months in these 31 patients was significantly longer than that of 9.3 months in the remaining 23 patients without EMBE placement (p < 0.05). Eighteen patients whose surgical margins were positive in the hepatic side bile duct(s) showed significantly better survival compared with 15 patients whose surgical margins were positive in the adjacent structure(s) (44% vs. 0% survival at 3 years, p < 0.001). No survival benefit was obtained in patients given palliative or preoperative radiotherapy

  15. Reaction rate constant for radiative association of CF{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Öström, Jonatan, E-mail: jonatan.ostrom@gmail.com; Gustafsson, Magnus, E-mail: magnus.gustafsson@ltu.se [Applied Physics, Division of Materials Science, Department of Engineering Science and Mathematics, Luleå University of Technology, 97187 Luleå (Sweden); Bezrukov, Dmitry S. [Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow, 119991 (Russian Federation); Nyman, Gunnar [Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg (Sweden)

    2016-01-28

    Reaction rate constants and cross sections are computed for the radiative association of carbon cations (C{sup +}) and fluorine atoms (F) in their ground states. We consider reactions through the electronic transition 1{sup 1}Π → X{sup 1}Σ{sup +} and rovibrational transitions on the X{sup 1}Σ{sup +} and a{sup 3}Π potentials. Semiclassical and classical methods are used for the direct contribution and Breit–Wigner theory for the resonance contribution. Quantum mechanical perturbation theory is used for comparison. A modified formulation of the classical method applicable to permanent dipoles of unequally charged reactants is implemented. The total rate constant is fitted to the Arrhenius–Kooij formula in five temperature intervals with a relative difference of <3%. The fit parameters will be added to the online database KIDA. For a temperature of 10–250 K, the rate constant is about 10{sup −21} cm{sup 3} s{sup −1}, rising toward 10{sup −16} cm{sup 3} s{sup −1} for a temperature of 30 000 K.

  16. Intraluminal brachytherapy in carcinoma of the oesophagus: comparison of afterloading techniques

    International Nuclear Information System (INIS)

    Udaya Kumar, M.; Supe, S.S.; Swamy, Kumara; Keshava, S.L.; Anantha, N.

    1993-01-01

    For improved local control or palliation of oesophageal cancers, intra-luminal brachytherapy (ILB) has emerged as an increasingly popular treatment modality of therapy in recent years. In combination with external radiotherapy, after-loaded ILB can increase local control rates and may prolong survival of these patients. In this paper two techniques of ILB viz., manual and low dose-rate remote after loading methods, using caesium-137 tubes and pellets respectively, are described in detail. On comparison of these two techniques it was found that both of them were similar with respect to their physical characteristic (dose rate, dose fall-off, maximum spinal cord dose, total reference air kerma, etc.). Clinically, the manual after-loaded ILB technique was found to be easier to use when compared with the low-dose rate remote after-loader. In addition, the number of patients with uterine cancers being high in a developing country, it was found that it was inappropriate to use the low dose remote after-loaders, designed for use in gynaecological cancers, for ILB of oesophageal cancers. Therefore, in the absence of high dose rate after-loaders, which can be utilized for intracavitary treatments of both uterine and oesophageal malignancies effectively, the manual after-loading ILB system as described in this paper could be a practical alternative. (author). 19 refs., 4 figs., 2 tabs

  17. String-like lumen in below-the-knee chronic total occlusions on contrast-enhanced magnetic resonance angiography predicts intraluminal recanalization and better blood flow restoration

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yue-Qi; Lu, Hai-Tao; Wei, Li-Ming; Cheng, Ying-Sheng; Wang, Jian-Bo; Zhao, Jun-Gong [Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, Department of Diagnostic and Interventional Radiology, Shanghai (China); Liu, Fang [Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, Department of Endocrinology, Shanghai (China)

    2017-07-15

    To determine whether string-like lumina (SLs) on contrast-enhanced magnetic resonance angiography (CE-MRA) predict better outcomes in diabetic patients with below-the-knee (BTK) chronic total occlusions (CTOs). This study involved 317 long-segment (>5 cm) BTK CTOs of 245 patients that were examined using CE-MRA and treated using endovascular angioplasty. An SL with a CTO was slowly filled with blood on conventional CE-MRA. Univariate and multivariate analyses were performed to identify predictors of procedural success, recanalisation method and immediate blood flow restoration. The target-lesion patency and limb-salvage rates were assessed. SL-positive CTOs (n = 60) achieved a higher technique success rate, preferred intraluminal angioplasty and better blood flow restoration than SL-negative CTOs (n = 257, P < 0.05). Multivariate analyses revealed that lesion length was the independent predictor of procedural success (P = 0.028). SL was a predictor of intraluminal angioplasty (P < 0.001) and good blood-flow restoration (P = 0.004). Kaplan-Meier analyses at 12 months revealed a higher target lesion patency rate (P = 0.04) and limb-salvage rate (P = 0.35) in SL-positive CTOs. In patients with BTK CTOs, SL predicted intraluminal angioplasty and good blood-flow restoration for BTK CTOs. (orig.)

  18. Surveillance of colorectal cancer: effectiveness of early detection of intraluminal recurrences on prognosis and survival of patients treated for cure.

    Science.gov (United States)

    Barillari, P; Ramacciato, G; Manetti, G; Bovino, A; Sammartino, P; Stipa, V

    1996-04-01

    The authors evaluate the effectiveness of routine colonoscopy and marker evaluation in diagnosis of intraluminal recurrent cancer. Chart review was conducted on 481 patients who underwent curative resection for colorectal cancer between 1980 and 1990. Clinical visits were scheduled and carcinoembryonic antigen evaluation was performed every three months, and colonoscopy was performed preoperatively, 12 to 15 months after surgical treatment, and then with intervals of 12 to 24 months or when symptoms appeared. About 10 percent of patients developed intraluminal recurrences. More than one-half of metachronous lesions arose within the first 24 months, and median time to diagnosis was 25 months. Patients with left-sited tumors in the advanced stage had a higher risk of developing recurrent intraluminal disease. Twenty-nine patients underwent a second surgical operation, of which 17 cases were radical. In this group, the five-year survival was 70.6 percent, although no nonradically treated or nonresected patients survived longer than 31 months. Twenty-two patients were asymptomatic at time of diagnosis of recurrence, and of these, 12 patients underwent radical operation; on the other hand, of the 24 symptomatic patients, only 5 were treated radically. Carcinoembryonic antigen was the first sign of recurrence in eight cases. Colonoscopy must be performed within the first 12 to 15 months after operation, whereas an interval of 24 months between examinations seems sufficient to guarantee early detection of metachronous lesions. Serial tumor marker evaluation is of help in earlier diagnosis of local recurrences. Asymptomatic patients more frequently undergo another operation for cure and thus have a better survival rate.

  19. Radiation dose rates from adult patients undergoing nuclear medicine investigations

    International Nuclear Information System (INIS)

    Mountford, P.J.; O'Doherty, M.J.; Forge, N.I.; Jeffries, A.; Coakley, A.J.

    1991-01-01

    Adult patients undergoing nuclear medicine investigations may subsequently come into close contact with members of the public and hospital staff. In order to expand the available dosimetry and derive appropriate recommendations, dose rates were measured at 0.1, 0.5 and 1.0 m from 80 adult patients just before they left the nuclear medicine department after undergoing one of eight 99 Tc m studies, an 123 I thyroid, an 111 In leucocyte or a 201 Tl cardiac scan. The maximum departure dose rates at these distances of 150, 30 and 7.3 μSv h -1 were greater than those found in similar published studies of adult and paediatric patients. To limit the dose to an infant to less than 1 mSv, an 111 In leucocyte scan is the only investigation for which it may be necessary to restrict close contact between the infant and a radioactive parent, depending on the dose rate near the surface of the patient, the parent's habits and how fretful is the infant. It is unlikely that a ward nurse will receive a dose of 60 μSv in a working day if caring for just one radioactive adult patient, unless the patient is classified as totally helpless and had undergone a 99 Tc m marrow, bone or brain scan. The data and revised calculations of effective exposure times based on a total close contact time of 9 h in every 24 h period should allow worst case estimates of radiation dose to be made and recommendations to be formulated for other circumstances, including any future legislative changes in dose limits or derived levels. (author)

  20. Tratamento cirúrgico em dois tempos do aneurisma toracoabdominal roto com prótese intraluminal sem sutura

    Directory of Open Access Journals (Sweden)

    Rodrigo de Castro BERNARDES

    1998-10-01

    Full Text Available O tratamento cirúrgico dos aneurismas toracoabominais exige toracofreno laparotomia, períodos prolongados de pinçamento aórtico com isquemia visceral, sangramento abundante de difícil controle, complicações pulmonares, renais, neurológicas e distúrbios de coagulação com morbimortalidade muitas vezes proibitiva para pacientes de idade avançada, ou portadores de distúrbios respiratórios, renais ou cardíacos prévios. A rotura aumenta em muito a já elevada taxa de morbimortalidade. Crawford (1-3 e Borst (4 descreveram operação em dois tempos para tratamento de aneurisma que atinge mais de um segmento da aorta, com bons resultados. O objetivo de nosso trabalho é mostrar a técnica cirúrgica em dois tempos, empregando prótese intraluminal sem sutura (5, 6. Esta técnica nos proporciona uma operação menos agressiva por abordar somente o segmento roto da aorta, portanto apenas uma cavidade é manipulada (tórax ou abdome. A anastomose com prótese intraluminal reduz em muito o tempo de pinçamento da aorta e, conseqüentemente, a isquemia visceral, diminuindo, também, o sangramento. A redução da agressividade cirúrgica sobre estes pacientes já gravemente enfermos nos proporcionou bons resultados cirúrgicos.The surgical management of thoracoabdominal aneurysms requires thoracophrenic laparotomy, prolonged periods of aortic clamping with visceral ischemia, profuse bleeding leading to a difficult postoperative course with pulmonary, renal, neurological complications, coagulation disturbances and others. All this resulting in an elevated morbidity/mortality very often contraindicating it for the very elderly or those with prior respiratory, renal or cardiac symptoms. Rupture of this aneurysm greatly increases the already high rate of morbidity/mortality. Crawford and Borst have described a two-stage surgery with good results, for aneurysms that affect more than one segment of aorta. The objective of our report is to demonstrate

  1. Angioplasty of symptomatic high-grade internal carotid artery stenosis with intraluminal thrombus: therapeutic approach

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, A.; Mayol, A. [Seccion de Neurorradiologia Intervencionista, Servicio de Radiologia, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain); Gil-Peralta, A.; Gonzalez-Marcos, J.R. [Servicio de Neurologia, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain); Boza, F. [Servicio de Neurofisiologia, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain); Ruano, J. [Unidad de Cuidados Intensivos, Hospital Universitario Virgen del Rocio, Avenida Manuel Siurot s/n, 41013, Sevilla (Spain)

    2004-04-01

    Intraluminal thrombus in the internal carotid artery (ICA) is usually found in patients with severe atheromatous stenosis. Having reviewed 300 carotid angioplasties for symptomatic >70% ICA stenosis, we found three patients (1%) with intraluminal thrombus. Conservative treatment with anticoagulants and double antiplatelet coverage can result in lysis of the thrombus without severe risks. Percutaneous transluminal angioplasty and stenting, preferably with distal protection, can be an excellent alternative to carotid endarterectomy. (orig.)

  2. Technological Advancements and Error Rates in Radiation Therapy Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Margalit, Danielle N., E-mail: dmargalit@partners.org [Harvard Radiation Oncology Program, Boston, MA (United States); Harvard Cancer Consortium and Brigham and Women' s Hospital/Dana Farber Cancer Institute, Boston, MA (United States); Chen, Yu-Hui; Catalano, Paul J.; Heckman, Kenneth; Vivenzio, Todd; Nissen, Kristopher; Wolfsberger, Luciant D.; Cormack, Robert A.; Mauch, Peter; Ng, Andrea K. [Harvard Cancer Consortium and Brigham and Women' s Hospital/Dana Farber Cancer Institute, Boston, MA (United States)

    2011-11-15

    Purpose: Technological advances in radiation therapy (RT) delivery have the potential to reduce errors via increased automation and built-in quality assurance (QA) safeguards, yet may also introduce new types of errors. Intensity-modulated RT (IMRT) is an increasingly used technology that is more technically complex than three-dimensional (3D)-conformal RT and conventional RT. We determined the rate of reported errors in RT delivery among IMRT and 3D/conventional RT treatments and characterized the errors associated with the respective techniques to improve existing QA processes. Methods and Materials: All errors in external beam RT delivery were prospectively recorded via a nonpunitive error-reporting system at Brigham and Women's Hospital/Dana Farber Cancer Institute. Errors are defined as any unplanned deviation from the intended RT treatment and are reviewed during monthly departmental quality improvement meetings. We analyzed all reported errors since the routine use of IMRT in our department, from January 2004 to July 2009. Fisher's exact test was used to determine the association between treatment technique (IMRT vs. 3D/conventional) and specific error types. Effect estimates were computed using logistic regression. Results: There were 155 errors in RT delivery among 241,546 fractions (0.06%), and none were clinically significant. IMRT was commonly associated with errors in machine parameters (nine of 19 errors) and data entry and interpretation (six of 19 errors). IMRT was associated with a lower rate of reported errors compared with 3D/conventional RT (0.03% vs. 0.07%, p = 0.001) and specifically fewer accessory errors (odds ratio, 0.11; 95% confidence interval, 0.01-0.78) and setup errors (odds ratio, 0.24; 95% confidence interval, 0.08-0.79). Conclusions: The rate of errors in RT delivery is low. The types of errors differ significantly between IMRT and 3D/conventional RT, suggesting that QA processes must be uniquely adapted for each technique

  3. Technological Advancements and Error Rates in Radiation Therapy Delivery

    International Nuclear Information System (INIS)

    Margalit, Danielle N.; Chen, Yu-Hui; Catalano, Paul J.; Heckman, Kenneth; Vivenzio, Todd; Nissen, Kristopher; Wolfsberger, Luciant D.; Cormack, Robert A.; Mauch, Peter; Ng, Andrea K.

    2011-01-01

    Purpose: Technological advances in radiation therapy (RT) delivery have the potential to reduce errors via increased automation and built-in quality assurance (QA) safeguards, yet may also introduce new types of errors. Intensity-modulated RT (IMRT) is an increasingly used technology that is more technically complex than three-dimensional (3D)–conformal RT and conventional RT. We determined the rate of reported errors in RT delivery among IMRT and 3D/conventional RT treatments and characterized the errors associated with the respective techniques to improve existing QA processes. Methods and Materials: All errors in external beam RT delivery were prospectively recorded via a nonpunitive error-reporting system at Brigham and Women’s Hospital/Dana Farber Cancer Institute. Errors are defined as any unplanned deviation from the intended RT treatment and are reviewed during monthly departmental quality improvement meetings. We analyzed all reported errors since the routine use of IMRT in our department, from January 2004 to July 2009. Fisher’s exact test was used to determine the association between treatment technique (IMRT vs. 3D/conventional) and specific error types. Effect estimates were computed using logistic regression. Results: There were 155 errors in RT delivery among 241,546 fractions (0.06%), and none were clinically significant. IMRT was commonly associated with errors in machine parameters (nine of 19 errors) and data entry and interpretation (six of 19 errors). IMRT was associated with a lower rate of reported errors compared with 3D/conventional RT (0.03% vs. 0.07%, p = 0.001) and specifically fewer accessory errors (odds ratio, 0.11; 95% confidence interval, 0.01–0.78) and setup errors (odds ratio, 0.24; 95% confidence interval, 0.08–0.79). Conclusions: The rate of errors in RT delivery is low. The types of errors differ significantly between IMRT and 3D/conventional RT, suggesting that QA processes must be uniquely adapted for each technique

  4. Efficacy of transoral intraluminal Wallstents for tracheal stenosis or tracheomalacia.

    Science.gov (United States)

    Casiano, R R; Numa, W A; Nurko, Y J

    2000-10-01

    The efficacy and safety of intraluminal Wallstent Endoprosthesis (Boston Scientific/ Medi-Tech, Quincy, MA) placement to restore airway patency in patients with tracheal stenosis or tracheomalacia are unknown. Retrospective review in setting of tertiary, referral, and academic center. A retrospective review of 13 consecutive patients over a 2-year period who underwent transoral resection of tracheal stenosis and immediate transoral Wallstent placement. One patient had tracheomalacia. All of the patients were considered at high risk for transcervical surgery or had failed prior traditional open procedures. The average patient age was 54.2 years, with nine male and four female patients. All had Cotton/Myer stenoses (grades II to IV) with moderate to severe degrees of inspiratory stridor. Four patients were tracheotomy dependent. The length of stenosis varied from 1 to 4 cm. One patient had a 10-cm segment of tracheomalacia. At the time of writing, none of the patients has had a problem with significant migration or extrusion and most of the patients have incorporated the stent well without any short-term obstructive granulation tissue. After a mean follow-up of 15 months (range, 4-24 mo). 10 of the 12 patients with stenosis (83%) have remained free of any inspiratory noise during breathing. The one patient with tracheomalacia also has remained free of symptoms. Transoral Wallstents appear to be safe and may be a reasonable alternative in the restoration of airway patency in select patients with tracheal stenosis or tracheomalacia.

  5. TIA model is attainable in Wistar rats by intraluminal occlusion of the MCA for 10min or shorter.

    Science.gov (United States)

    Durukan Tolvanen, A; Tatlisumak, E; Pedrono, E; Abo-Ramadan, U; Tatlisumak, T

    2017-05-15

    Transient ischemic attack (TIA) has received only little attention in the experimental research field. Recently, we introduced a TIA model for mice, and here we set similar principles for simulating this human condition in Wistar rats. In the model: 1) transient nature of the event is ensured, and 2) 24h after the event animals are free from any sensorimotor deficit and from any detectable lesion by magnetic resonance imaging (MRI). Animals experienced varying durations of ischemia (5, 10, 12.5, 15, 25, and 30min, n=6-8pergroup) by intraluminal middle cerebral artery occlusion (MCAO). Ischemia severity and reperfusion rates were controlled by cerebral blood flow measurements. Sensorimotor neurological evaluations and MRI at 24h differentiated between TIA and ischemic stroke. Hematoxylin and eosin staining and apoptotic cell counts revealed pathological correlates of the event. We found that already 12.5min of ischemia was long enough to induce ischemic stroke in Wistar rats. Ten min or shorter durations induced neither gross neurological deficits nor infarcts visible on MRI, but histologically caused selective neuronal necrosis. A separate group of animals with 10min of ischemia followed up to 1week after reperfusion remained free of infarction and any MRI signal change. Thus, 10min or shorter focal cerebral ischemia induced by intraluminal MCAO in Wistar rats provides a clinically relevant TIA the rat. This model is useful for studying molecular correlates of TIA. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Elevated Rate of Genome Rearrangements in Radiation-Resistant Bacteria

    OpenAIRE

    Repar, Jelena; Supek, Fran; Klanjscek, Tin; Warnecke, Tobias; Zahradka, Ksenija; Zahradka, Davor

    2017-01-01

    A number of bacterial, archaeal, and eukaryotic species are known for their resistance to ionizing radiation. One of the challenges these species face is a potent environmental source of DNA double-strand breaks, potential drivers of genome structure evolution. Efficient and accurate DNA double-strand break repair systems have been demonstrated in several unrelated radiation-resistant species and are putative adaptations to the DNA damaging environment. Such adaptations are expected to compen...

  7. Injury of the blood-testies barrier after low-dose-rate chronic radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Young Hoon; Bae Min Ji; Lee, Chang Geun; Yang, Kwang Mo; Jur, Kyu; Kim, Jong Sun [Dongnam Institute of Radiological and Medical Science, Busan (Korea, Republic of)

    2014-04-15

    The systemic effect of radiation increases in proportionally with the dose and dose rate. Little is known concerning the relationships between harmful effects and accumulated dose, which is derived from continuous low-dose rate radiation exposure. Recent our studies show that low-dose-rate chronic radiation exposure (3.49 mGy/h) causes adverse effects in the testis at a dose of 2 Gy (6 mGy/h). However, the mechanism of the low-dose-rate 2 Gy irradiation induced testicular injury remains unclear. The present results indicate that low-dose rate chronic radiation might affect the BTB permeability, possibly by decreasing levels of ZO-1, Occludin-1, and NPC-2. Furthermore, our results suggest that there is a risk of male infertility through BTB impairment even with low-dose-rate radiation if exposure is continuous.

  8. Enhanced escape rate for Hg 254 nm resonance radiation in fluorescent lamps

    International Nuclear Information System (INIS)

    Lawler, James E; Raizen, Mark G

    2013-01-01

    The potential of the low-cost MAGIS isotopic separation method to improve fluorescent lamp efficacy is explored using resonance radiation transport simulations. New Hg isotopic mixes are discovered that yield escape rates for 254 nm Hg I resonance radiation equal to 117% to 122% of the rate for a natural isotopic mix under the same lamp conditions. (paper)

  9. Radiation therapy in the treatment of hilar cholangiocarcinoma

    International Nuclear Information System (INIS)

    Jing Jin; Zhai Renyou

    2007-01-01

    The incidence of hilar cholangiocarcinoma is very rare worldwide. Radical resection is the only prognostic factor for long survival in patients with hilar cholangiocarcinoma. Postoperative radiation therapy can improve local control and survival rates for patients with palliative resection, but it remains controversial in patients with radical resection. Biliary drainage can effectively release bile duct obstruction for the majority of patients with locally advanced disease, and may even prolong survival when combined with radiation therapy. Radiation therapy includes extrernal beam therapy alone, external beam therapy with intraluminal brachytheapy and new radiation technique, such as three dimentional conformal therapy and intensity modulated radiation therapy. The propective randomized clinical study is needed for further investigation in the role of combined modality therapy especially for hilar cholangiocarcinoma. (authors)

  10. Influence of atmospheric rainfall to γ radiation Kerma rate in surface air

    International Nuclear Information System (INIS)

    Xu Zhe; Wan Jun; Yu Rongsheng

    2009-01-01

    Objective: To investigate the influence rule of the atmospheric Rainfall to the γ radiation Kerma rate in surface air in order to revise the result of its measurement during rainfall. Methods: The influence factors of rainfall to the measurement of the γ radiation Kerma rate in air were analyzed and then the differential equation of the correlation factors was established theoretically, and by resolving the equation, the mathematical model Was obtained. The model was discussed through several practical examples. Results: The mathematical model was coincided with the tendency of curve about the measured data on the influence rule of rainfall to the γ radiation Kerma rate in surface air. Conclusion: By using the theoretical formula in this article which is established to explain the relationship between the rainfall and the γ radiation Kerma rate in surface air, the influence of rainfall to the γ radiation Kerma rate in surface air could be correctly revised. (authors)

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

    International Nuclear Information System (INIS)

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

    1993-08-01

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

  12. Intraluminal erosion of laparoscopic gastric band tubing into duodenum with recurrent port-site infections.

    Science.gov (United States)

    Cintolo, Jessica A; Levine, Marc S; Huang, Stephanie; Dumon, Kristoffel

    2012-01-01

    Intraluminal erosion of a laparoscopic gastric band into the stomach has been reported as a complication of laparoscopic adjustable gastric banding. To our knowledge, however, intraluminal erosion of the band tubing into the duodenum has not been described. We report a 46-year-old man in whom a laparoscopic adjustable gastric band tubing eroded into the duodenal lumen, causing recurrent port-site infections. This complication was diagnosed on upper endoscopy and also, in retrospect, on an upper gastrointestinal barium study and computed tomography. The patient underwent surgical removal of the band and tubing, with a primary duodenal repair, and made a complete recovery without complications. Erosion of laparoscopic band tubing into the duodenum should be included in the differential diagnosis for recurrent port-site infections after laparoscopic adjustable gastric banding. Radiographic or endoscopic visualization of the intraluminal portion of the tubing may be required for confirmation. Definitive treatment of this complication entails surgical removal of the tubing from the duodenum.

  13. Why heavy and light quarks radiate energy with similar rates

    International Nuclear Information System (INIS)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

    2010-01-01

    The dead-cone effect has been predicted to reduce the magnitude of energy loss and jet quenching for heavy flavors produced with large p T in heavy-ion collisions. On the contrary, data from the Relativistic Heavy Ion Collider demonstrate a strong suppression of high-p T electrons from charm and bottom decays. We show that vacuum radiation of a highly virtual quark produced at high p T with a stripped-off color field develops a much wider dead cone, which screens the one related to the quark mass. Lacking the field, gluons cannot be radiated within this cone until the color field is regenerated and the quark virtuality cools down to the scale of the order of the quark mass. However, this takes longer than is essential for the observed jet quenching, leading to similar nuclear effects for the light and charm quark jets. Open beauty is expected to radiate much less within the p T range studied so far in heavy-ion collisions.

  14. Comparative investigation of three dose rate meters for their viability in pulsed radiation fields

    International Nuclear Information System (INIS)

    Gotz, M; Karsch, L; Pawelke, J

    2015-01-01

    Pulsed radiation fields, characterized by microsecond pulse duration and correspondingly high pulse dose rates, are increasingly used in therapeutic, diagnostic and research applications. Yet, dose rate meters which are used to monitor radiation protection areas or to inspect radiation shielding are mostly designed, characterized and tested for continuous fields and show severe deficiencies in highly pulsed fields. Despite general awareness of the problem, knowledge of the specific limitations of individual instruments is very limited, complicating reliable measurements. We present here the results of testing three commercial dose rate meters, the RamION ionization chamber, the LB 1236-H proportional counter and the 6150AD-b scintillation counter, for their response in pulsed radiation fields of varied pulse dose and duration. Of these three the RamION proved reliable, operating in a pulsed radiation field within its specifications, while the other two instruments were only able to measure very limited pulse doses and pulse dose rates reliably. (paper)

  15. Palliation in esophageal cancer with a single session of intraluminal irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Jager, J.J.; Pannebakker, M.; Vos, J. de (Radiotherapeutic Institute Limburg, Heerlen (Netherlands)); Rijken, J. (De Wever Hospital, Heerlen (Netherlands). Department of Internal Medicine); Vismans, F.J.F.E. (University Hospital Maastricht (Netherlands). Department of Gastroenterology)

    1992-10-01

    From September 1987-December 1989, 36 patients with advanced esophageal cancer entered a study in order to determine the efficacy of palliation by a single session of intraluminal irradiation. A dose of 15 Gy was administered at 1 cm distance from the central axis of the applicator. In 22 of 32 patients alive at least 6 weeks after treatment dysphagia improved, in 14 this relief was complete. Re-obstruction occurred in 8 of the 36 patients. Intraluminal irradiation is easy to administer and safe, it forms a useful addition to the therapeutic possibilities for the palliation of esophageal cancer. (author). 12 refs., 2 figs., 1 tab.

  16. Clinical observation of intraluminal stent angioplasty in the treatment of renal arterial stenoses

    International Nuclear Information System (INIS)

    Lu Yanwen; Zhang Jian; Huang Xianglong

    2002-01-01

    Objective: To evaluate the clinical application of intraluminal stent angioplasty (PTRAS) in the treatment of renal arterial stenoses. Methods: A retrospective study was done in 28 patients with renal arterial stenoses. Primary renal artery stenting was performed in 28 consecutive patients (36 renal arteries). Blood pressure, serum creating, the number of anti-hypertensive medications were recorded at 1, 6, 12 month post stent angioplasty respectively. Arterial angiography was also taken 1 year later to evaluate the incidence of restenosis. Results: Technical success rate was 100% achieving in all patients without serious complications. Primary successful patently rate reached 82% (renal artery 86%), secondary successful rate was 89% (renal artery 90%). Systolic and diastolic blood pressure were reduced significantly (P<0.01) at 1,6,12 month after stent angioplasty comparing with baseline and clinical improvement (cured + improved) of hypertension reached 100%, 92.9%, 89.3% respectively. There were no significant differences between serum creatine level and the number of anti-hypertensive medications before and after stent angioplasty. One year later, 14.3% of all patients showed improvement of renal function, 64.3% remained in stabilization and 21.4% fell into deterioration. Angiographic restenosis was found in 3 cases one year after stent angioplasty. Complications included 1 hematoma at puncture site and 3 transient azotaemia. Conclusions: PTRAS can be performed safely with high technical success and beneficial to the majority of patients with hypertension or renal insufficiency and therefore it should be the first choice in treating renal arterial stenoses

  17. 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

  18. Design And Measurement Of Radiation Exposure Rates At An X-Ray Diagnostic Radiological Unit

    International Nuclear Information System (INIS)

    Tito-Sutjipto

    2003-01-01

    Every radiation employees suffers radiation exposure risk while doing his job. It is important therefore to investigate the occupational health and safety of radiation employees on its relationship with the design and measurement of radiation exposure rates at an X-ray diagnostic radiological unit in this work, a case study was held on the radiological unit at BP-4 Yogyakarta for patient diagnostics, This research armed to investigate the relationship between the design of radiological unit for X-ray diagnostics and the location of the X-ray machine, based on the distance variable and radiation exposure rate during patient diagnostics. This was performed using radiological unit design data for X-ray diagnostics and the measurement of radiation exposure rates throughout patient diagnostics. The design data can then be used for determining the requirement of primary and secondary shielding materials for radiological unit as well as a calculation basis of radiation exposure rates during patient diagnostics. From the result of the research, it can be concluded that from the occupational health and safety point of view, radiation exposure around the X-ray machines are fairly good, both for the shielding materials in each X-ray room and the radiation exposures received by the workers, because they are far beyond the maximum permittable average limit (16.67 m R/days). (author)

  19. Dissolution rate and radiation dosimetry of metal tritides

    International Nuclear Information System (INIS)

    Jow, Hong-Nian; Cheng, Yung-Sung

    1993-01-01

    Metal tritides including titanium tritide (Ti 3 H x ) and erbium tritide (Er 3 H x ) have been used as components of neutron generators. These compounds can be released to the air as aerosols during fabrication, assembling and testing of components or in accidental or fugitive releases. As a result, workers could be exposed to these compounds by inhalation. A joint research project between SNL and ITRI (Inhalation Toxicology Research Institute) was initiated last fall to investigate the solubility of metal tritides, retention and translocation of inhaled particles and internal dosimetry of metal tritides. The current understanding of metal tritides and their radiation dosimetry for internal exposure are very limited. There is no provision in the ICRP-30 for tritium dosimetry in metal tritide form. However, a few papers in the literature suggested that the solubility of metal tritide could be low. The current radiation protection guidelines for metal tritide particles are based on the assumption that the biological behavior is similar to tritiated water which behaves like body fluid with a relative short biological half life (10 days). If the solubility of metal tritide is low, the biological half life of metal tritide particles and the dosimetry of inhalation exposure to these particles could be quite different from tritiated water. This would have major implications in current radiation protection guidelines for metal tritides Including annual limits of intakes and derived air concentrations. The preliminary results of metal tritide dissolution study at ITRI indicate that the solubility of titanium tritide is low. The outlines of the project, the preliminary results and future work will be discussed in presentation

  20. Dose rate from the square volume radiation source

    International Nuclear Information System (INIS)

    Karpov, V.I.

    1978-01-01

    The expression for determining the dose rate from a three-dimensional square flat-parallel source of any dimensions is obtained. A simplified method for integrating the resultant expression is proposed. A comparison of the calculation results with the results by the Monte Carlo method has shown them to coincide within 6-8%. Since buildings and structures consist of rectangular elements, the method is recommended for practical calculations of dose rates in residential buildings

  1. Recommended de minimis radiation dose rates for Canada

    International Nuclear Information System (INIS)

    1990-07-01

    A de minimis dose or dose rate as used in this report represents a level of risk which is generally accepted as being of no significance to an individual, or in the case of a population, of no significance to society. The doses corresponding to these levels of risk are based on current scientific knowledge. Dose rates recommended in this report are as follows: a de minimis individual dose rate of 10 μSv a -1 , based on a risk level that would generally be regarded as negligible in comparison with other risks; and a de minimis collective dose rate of 1 person-Sv a -1 , based on an imperceptible increase above the normal incidences of cancer and genetic defects in the exposed population. The concept of de minimis is to be distinguished from 'exempt from regulation' (below regulatory concern). The latter involves broader social and economic factors which encompass but are not limited to the purely risk-based factors addressed by the de minimis dose. De minimis is one of the factors that determine the exemption of sources or practices that may result in doses below or above the de minimis level. Although these de minimis dose rates should be considered in developing criteria and guidelines for deriving quantities and concentrations of radioactive substances that may be exempted from regulation, this document is only concerned with establishing de minimis dose rates, not with exempting sources and practices

  2. An energy-independent dose rate meter for beta and gamma radiation

    International Nuclear Information System (INIS)

    Heinzelmann, M.; Keller, M.

    1986-01-01

    An easy to handle dose rate meter has been developed at the Juelich Nuclear Research Centre with a small probe for the energy-independent determination of the dose rate in mixed radiation fields. The dose rate meter contains a small ionisation chamber with a volume of 15.5 cm 3 . The window of the ionisation chamber consists of an aluminised plastic foil of 7 mg.cm -2 . The dose rate meter is suitable for determining the dose rate in skin. With a supplementary depth dose cap, the dose rate can be determined in tissue at a depth of 1 cm. The dose rate meter is energy-independent within +-20% for 147 Pm, 204 Tl and 90 Sr/ 90 Y beta radiation and for gamma radiation in the energy range above 35 keV. (author)

  3. Effect of radiation doses rate on SOS response induction in irradiated Escherichia coli Cells

    International Nuclear Information System (INIS)

    Cuetara Lugo, Elizabeth B.; Fuentes Lorenzo, Jorge L.; Almeida Varela, Eliseo; Prieto Miranda, Enrique F.; Sanchez Lamar, Angel; Llagostera Casal, Montserrat

    2005-01-01

    The present work is aimed to study the effect of radiation dose rate on the induction of SOS response in Escherichia coli cells. We measured the induction of sul A reporter gene in PQ-37 (SOS Chromotest) cells. Lead devises were built with different diameter and these were used for diminishing the dose rate of PX- -30M irradiator. Our results show that radiation doses rate significantly modifies the induction of SOS response. Induction factor increases proportionally to doses rate in Escherichia coli cells defective to nucleotide excision repair (uvrA), but not in wild type cells. We conclude that the dose rate affects the level of induction of SOS response

  4. [Dose rate-dependent cellular and molecular effects of ionizing radiation].

    Science.gov (United States)

    Przybyszewski, Waldemar M; Wideł, Maria; Szurko, Agnieszka; Maniakowski, Zbigniew

    2008-09-11

    The aim of radiation therapy is to kill tumor cells while minimizing damage to normal cells. The ultimate effect of radiation can be apoptotic or necrotic cell death as well as cytogenetic damage resulting in genetic instability and/or cell death. The destructive effects of radiation arise from direct and indirect ionization events leading to peroxidation of macromolecules, especially those present in lipid-rich membrane structures as well as chromatin lipids. Lipid peroxidative end-products may damage DNA and proteins. A characteristic feature of radiation-induced peroxidation is an inverse dose-rate effect (IDRE), defined as an increase in the degree of oxidation(at constant absorbed dose) accompanying a lower dose rate. On the other hand, a low dose rate can lead to the accumulation of cells in G2, the radiosensitive phase of the cell cycle since cell cycle control points are not sensitive to low dose rates. Radiation dose rate may potentially be the main factor improving radiotherapy efficacy as well as affecting the intensity of normal tissue and whole-body side effects. A better understanding of dose rate-dependent biological effects may lead to improved therapeutic intervention and limit normal tissue reaction. The study reviews basic biological effects that depend on the dose rate of ionizing radiation.

  5. Transperineal high-dose-rate interstitial radiation therapy in the management of gynecologic malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Itami, Jun; Hara, Ryuseke; Kozuka, Takuyou; Yamashita, Hideomi; Nakajima, Kaori; Shibata, Kouji; Abe, Yoshihisa; Fuse, Masashi; Ito, Masashi [International Medical Center of Japan, Tokyo (Japan). Dept. of Radiation Therapy and Oncology

    2003-11-01

    Background: High-dose-rate interstitial radiation therapy is a newly introduced modality, and its role in the management of gynecologic malignancies remains to be studied. Clinical experience in high-dose-rate interstitial radiation therapy was retrospectively investigated. Patients and Methods: Eight patients with primary and nine with recurrent gynecologic malignancies underwent high-dose-rate interstitial radiation therapy with/without external-beam irradiation. Fractional dose of the high-dose-rate interstitial radiation therapy ranged between 4 and 6 Gy with total doses of 15-54 Gy. Interstitial irradiation was performed twice daily with an interval of > 6 h. Results: 2-year local control rate was 75% for primary treatment and 47% for treatment of recurrence (p = 0.46). Maximum tumor size had a statistically significant impact on local control (p < 0.002). Grade 2 and 4 late complications were seen in five patients, and the incidence was significantly higher in patients with a larger volume enclosed by the prescribed fractional dose of high-dose-rate interstitial radiation therapy. The incidence of grade 2 and 4 complications at 18 months was 78% and 0% with a volume > 100 cm{sup 3} and {<=} 100 cm{sup 3}, respectively (p < 0.04). Conclusion: Although high-dose-rate interstitial radiation therapy is a promising modality, it must be applied cautiously to patients with bulky tumors because of the high incidence of serious complications. (orig.)

  6. Study on the evaluation method of radiation dose rate around spent fuel shipping casks

    International Nuclear Information System (INIS)

    Yamakoshi, Hisao

    1986-01-01

    This study aims at developing a simple calculation method which can evaluate radiation dose rate around casks with high accuracy in a short time. The method is based on a concept of the radiation shielding characteristics of cask walls. The concept was introduced to replace for ordinary radiation shielding calculation which requires a long calculation time and a large memory capacity of a computer in the matrix calculation. For the purpose of verifying the accuracy and reliability of the new method, it was applied to the analysis of the dose rate distribution around actual casks, which had been measured. The results of the analysis revealed that the newly proposed method was excellent for the forecast of radiation dose rate distribution around casks in view of the accuracy and calculation time. The short calculation time and high accuracy by the proposed method were attained by dividing the whole procedure of ordinary fine radiation shielding calculation into the calculation of radiation dose rate on a cask surface by the matrix expression of the characteristic function and the calculation of dose rate distribution using the simple analytical expression of dose rate distribution around casks. The effect of the heterogeneous array of spent fuel in different burnup state on dose rate distribution around casks was evaluated by this method. (Kako, I.)

  7. Radiative losses and electron cooling rates for carbon and oxygen plasma impurities

    International Nuclear Information System (INIS)

    Marchand, R.; Bonnin, X.

    1992-01-01

    Radiative losses and electron cooling rates are calculated for carbon and oxygen ions under conditions relevant to fusion plasmas. Both rates are calculated with the most recent recommended atomic data. A modified coronal model which includes the effects of metastable states is described and used to calculate the rates. Comparisons with other approaches are also discussed. (author). 36 ref, figs

  8. Comparative influence of dose rate and radiation nature, on lethality after big mammals irradiation

    International Nuclear Information System (INIS)

    Destombe, C.; Le Fleche, Ph.; Grasseau, A.; Reynal, A.

    1997-01-01

    For the same dose and the 30 days lethality as biological criterion, the dose rate influence is more important than the radiation nature on the results of an big mammals total body irradiation. (authors)

  9. Investigations on commercial semiconductor diodes as possible high dose rate radiation detectors

    International Nuclear Information System (INIS)

    Breitenhuber, L.; Kindl, P.; Obenaus, B.

    1992-12-01

    Investigations concerning the relevant properties of commercial semiconductor diodes such as their sensitivity and its dependence on accumulated dose, dose rate, energy, temperature and direction have been made in order to obtain their usefullness as radiation detectors. (authors)

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

    CERN Document Server

    Sakamoto, Y

    2002-01-01

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

  11. Multichannel intraluminal impedance monitoring in the evaluation of patients with non-obstructive Dysphagia

    NARCIS (Netherlands)

    Conchillo, José M.; Nguyen, Nam Q.; Samsom, Melvin; Holloway, Richard H.; Smout, André J. P. M.

    2005-01-01

    BACKGROUND: Non-obstructive dysphagia (NOD) often poses diagnostic problems. The aim of this study was to evaluate the value of the addition of multichannel intraluminal impedance (MII) recording to esophageal manometry in the work-up of patients with NOD. METHODS: A total of 40 consecutive patients

  12. Multichannel intraluminal impedance monitoring in the evaluation of patients with non-obstructive dysphagia

    NARCIS (Netherlands)

    Conchillo, JM; Nguyen, NQ; Samsom, M; Holloway, RH; Smout, AJPM

    2005-01-01

    BACKGROUND: Non-obstructive dysphagia (NOD) often poses diagnostic problems. The aim of this study was to evaluate the value of the addition of multichannel intraluminal impedance (MII) recording to esophageal manometry in the work-up of patients with NOD. METHODS: A total of 40 consecutive patients

  13. Magnetic Retraction of Bowel by Intraluminal Injectable Cyanoacrylate-Based Magnetic Glue

    Directory of Open Access Journals (Sweden)

    Zhigang Wang

    2013-01-01

    Full Text Available Magnetic retraction offers advantages over physical retraction by graspers because of reduced tissue trauma. The objectives of this study are to investigate a novel method of magnetisation of bowel segments by intraluminal injection of magnetic glue and to demonstrate the feasibility of magnetic retraction of bowel with sufficient force during minimal access surgery. Following an initial materials characterisation study, selected microparticles of stainless steel (SS410-μPs were mixed with chosen cyanoacrylate glue (Loctite 4014. During intraluminal injection of the magnetic glue using ex vivo porcine colonic segments, a magnetic probe placed at the injected site ensured that the SS410-μPs aggregated during glue polymerisation to form an intraluminal mucosally adherent coagulum. The magnetised colonic segments were retracted by magnetic probes (5 and 10 mm placed external to the bowel wall. A tensiometer was used to record the retraction force. With an injected volume of 2 mL in a particle concentration of 1 g/mL, this technique produced maximal magnetic retraction forces of 2.24 ± 0.23 N and 5.11 ± 0.34 N (, with use of 5 and 10 mm probes, respectively. The results indicate that the formation of an intraluminal coagulum based on SS410-μPs and Loctite 4014 produces sufficient magnetic retraction for bowel retraction.

  14. A photocurrent compensation method of bipolar transistors under high dose rate radiation and its experimental research

    International Nuclear Information System (INIS)

    Yin Xuesong; Liu Zhongli; Li Chunji; Yu Fang

    2005-01-01

    Experiment using discrete bipolar transistors has been performed to verify the effect of the photocurrent compensation method. The theory of the dose rate effects of bipolar transistors and the photocurrent compensation method are introduced. The comparison between the response of hardened and unhardened circuits under high dose rate radiation is discussed. The experimental results show instructiveness to the hardness of bipolar integrated circuits under transient radiation. (authors)

  15. Collection of radiation resistant characteristics reports for instruments and materials in high dose rate environment

    International Nuclear Information System (INIS)

    Kusano, Joichi

    2008-03-01

    This document presents the collected official reports of radiation irradiation study for the candidate materials to be used in high dose rate environment as J-PARC facility. The effect of radiation damage by loss-beam or secondary particle beam of the accelerators influences the performance and the reliability of various instruments. The knowledge on the radiation resistivity of the materials is important to estimate the life of the equipments, the maintenance interval and dose evaluation for the personnel at the maintenance period. The radiation damage consists with mechanical property, electrical property and gas-evolution property. (author)

  16. Solar radiation increases suicide rate after adjusting for other climate factors in South Korea.

    Science.gov (United States)

    Jee, Hee-Jung; Cho, Chul-Hyun; Lee, Yu Jin; Choi, Nari; An, Hyonggin; Lee, Heon-Jeong

    2017-03-01

    Previous studies have indicated that suicide rates have significant seasonal variations. There is seasonal discordance between temperature and solar radiation due to the monsoon season in South Korea. We investigated the seasonality of suicide and assessed its association with climate variables in South Korea. Suicide rates were obtained from the National Statistical Office of South Korea, and climatic data were obtained from the Korea Meteorological Administration for the period of 1992-2010. We conducted analyses using a generalized additive model (GAM). First, we explored the seasonality of suicide and climate variables such as mean temperature, daily temperature range, solar radiation, and relative humidity. Next, we identified confounding climate variables associated with suicide rate. To estimate the adjusted effect of solar radiation on the suicide rate, we investigated the confounding variables using a multivariable GAM. Suicide rate showed seasonality with a pattern similar to that of solar radiation. We found that the suicide rate increased 1.008 times when solar radiation increased by 1 MJ/m 2 after adjusting for other confounding climate factors (P Solar radiation has a significant linear relationship with suicide after adjusting for region, other climate variables, and time trends. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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

    International Nuclear Information System (INIS)

    Cantinha, Rebeca S.; Nakano, Eliana; Silva, Luanna R.S.

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-01

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

  19. Review of low dose-rate epidemiological studies and biological mechanisms of dose-rate effects on radiation induced carcinogenesis

    International Nuclear Information System (INIS)

    Iwasaki, Toshiyasu; Otsuka, Kensuke; Yoshida, Kazuo

    2015-01-01

    Radiation protection system adopts the linear non-threshold model with using dose and dose-rate effectiveness factor (DDREF). The dose-rate range where DDREF is applied is below 100 mGy per hour, and it is regarded that there are no dose-rate effects at very low dose rate, less than of the order of 10 mGy per year, even from the biological risk evaluation model based on cellular and molecular level mechanisms for maintenance of genetic integrity. Among low dose-rate epidemiological studies, studies of residents in high natural background areas showed no increase of cancer risks at less than about 10 mGy per year. On the other hand, some studies include a study of the Techa River cohort suggested the increase of cancer risks to the similar degree of Atomic bomb survivor data. The difference of those results was supposed due to the difference of dose rate. In 2014, International Commission on Radiological Protection opened a draft report on stem cell biology for public consultations. The report proposed a hypothesis based on the new idea of stem cell competition as a tissue level quality control mechanism, and suggested that it could explain the dose-rate effects around a few milligray per year. To verify this hypothesis, it would be needed to clarify the existence and the lowest dose of radiation-induced stem cell competition, and to elucidate the rate of stem cell turnover and radiation effects on it. As for the turnover, replenishment of damaged stem cells would be the important biological process. It would be meaningful to collect the information to show the difference of dose rates where the competition and the replenishment would be the predominant processes. (author)

  20. 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

  1. Study of the effect of dose-rate on radiation-induced damage to human erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Krokosz, Anita [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)]. E-mail: krokosz@biol.uni.lodz.pl; Koziczak, Renata [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Gonciarz, Marta [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Szweda-Lewandowska, Zofia [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)

    2006-01-15

    Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%) were irradiated with {gamma}-rays at three dose-rates of 66.7, 36.7, 25 Gy min{sup -1} in order to investigate the influence of the dose-rate on radiation-induced membrane damage, hemoglobin oxidation and loss of reduced glutathione. The obtained results showed that such processes as erythrocyte hemolysis, lipid and protein destruction depend on the radiation dose-rate. The parameter values describing these processes showed an inverse dose-rate effect.

  2. Study of the effect of dose-rate on radiation-induced damage to human erythrocytes

    International Nuclear Information System (INIS)

    Krokosz, Anita; Koziczak, Renata; Gonciarz, Marta; Szweda-Lewandowska, Zofia

    2006-01-01

    Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%) were irradiated with γ-rays at three dose-rates of 66.7, 36.7, 25 Gy min -1 in order to investigate the influence of the dose-rate on radiation-induced membrane damage, hemoglobin oxidation and loss of reduced glutathione. The obtained results showed that such processes as erythrocyte hemolysis, lipid and protein destruction depend on the radiation dose-rate. The parameter values describing these processes showed an inverse dose-rate effect

  3. Genotoxic effects of high dose rate X-ray and low dose rate gamma radiation in ApcMin/+ mice.

    Science.gov (United States)

    Graupner, Anne; Eide, Dag M; Brede, Dag A; Ellender, Michele; Lindbo Hansen, Elisabeth; Oughton, Deborah H; Bouffler, Simon D; Brunborg, Gunnar; Olsen, Ann Karin

    2017-10-01

    Risk estimates for radiation-induced cancer in humans are based on epidemiological data largely drawn from the Japanese atomic bomb survivor studies, which received an acute high dose rate (HDR) ionising radiation. Limited knowledge exists about the effects of chronic low dose rate (LDR) exposure, particularly with respect to the application of the dose and dose rate effectiveness factor. As part of a study to investigate the development of colon cancer following chronic LDR vs. acute HDR radiation, this study presents the results of genotoxic effects in blood of exposed mice. CBAB6 F1 Apc +/+ (wild type) and Apc Min/+ mice were chronically exposed to estimated whole body absorbed doses of 1.7 or 3.2 Gy 60 Co-γ-rays at a LDR (2.2 mGy h -1 ) or acutely exposed to 2.6 Gy HDR X-rays (1.3 Gy min -1 ). Genotoxic endpoints assessed in blood included chromosomal damage (flow cytometry based micronuclei (MN) assay), mutation analyses (Pig-a gene mutation assay), and levels of DNA lesions (Comet assay, single-strand breaks (ssb), alkali labile sites (als), oxidized DNA bases). Ionising radiation (ca. 3 Gy) induced genotoxic effects dependent on the dose rate. Chromosomal aberrations (MN assay) increased 3- and 10-fold after chronic LDR and acute HDR, respectively. Phenotypic mutation frequencies as well as DNA lesions (ssb/als) were modulated after acute HDR but not after chronic LDR. The Apc Min/+ genotype did not influence the outcome in any of the investigated endpoints. The results herein will add to the scant data available on genotoxic effects following chronic LDR of ionising radiation. Environ. Mol. Mutagen. 58:560-569, 2017. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.

  4. Assessment of terrestrial gamma radiation dose rate (TGRD) of Kelantan State, Malaysia. Relationship between the geological formation and soil type to radiation dose rate

    International Nuclear Information System (INIS)

    Garba, N.N.; Gabdo, H.T.; Federal College of Education, Yola

    2014-01-01

    Terrestrial gamma radiation dose rates (TGRD) of Kelantan State were measured in situ using a portable [NaI(TI)] micro roentgen (μR) survey meter. The TGRD rates ranged between 44 and 500 nGy h -1 with a mean value of 209 ± 8 nGy h -1 . The distribution of these measurements in various districts of the state shows the statistically the influence of geology and soil types on the dose rate values. The data obtained could be used in formulating safety standard and radiological guidelines. (author)

  5. Determination of dose rates in beta radiation fields using extrapolation chamber and GM counter

    International Nuclear Information System (INIS)

    Borg, J.; Christensen, P.

    1995-01-01

    The extrapolation chamber measurement method is the basic method for the determination of dose rates in beta radiation fields and the method has been used for the establishment of beta calibration fields. The paper describes important details of the method and presents results from the measurements of depth-dose profiles from different beta radiation fields with E max values down to 156 keV. Results are also presented from studies of GM counters for use as survey instruments for monitoring beta dose rates at the workplace. Advantages of GM counters are a simple measurement technique and high sensitivity. GM responses were measured from exposures in different beta radiation fields using different filters in front of the GM detector and the paper discusses the possibility of using the results from GM measurements with two different filters in an unknown beta radiation field to obtain a value of the dose rate. (Author)

  6. The log mean heat transfer rate method of heat exchanger considering the influence of heat radiation

    International Nuclear Information System (INIS)

    Wong, K.-L.; Ke, M.-T.; Ku, S.-S.

    2009-01-01

    The log mean temperature difference (LMTD) method is conventionally used to calculate the total heat transfer rate of heat exchangers. Because the heat radiation equation contains the 4th order exponential of temperature which is very complicate in calculations, thus LMTD method neglects the influence of heat radiation. From the recent investigation of a circular duct in some practical situations, it is found that even in the situation of the temperature difference between outer duct surface and surrounding is low to 1 deg. C, the heat radiation effect can not be ignored in the situations of lower ambient convective heat coefficient and greater surface emissivities. In this investigation, the log mean heat transfer rate (LMHTR) method which considering the influence of heat radiation, is developed to calculate the total heat transfer rate of heat exchangers.

  7. 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.)

  8. Risk of radiation-induced cancer at low doses and low dose rates for radiation protection purposes

    International Nuclear Information System (INIS)

    1995-01-01

    The aim of this report is to provide an updated, comprehensive review of the data available for assessing the risk of radiation-induced cancer for radiation protection purposes. Particular emphasis is placed on assessing risks at low doses and low dose rates. The review brings together the results of epidemiological investigations and fundamental studies on the molecular and cellular mechanisms involved in radiation damage. Additionally, this information is supplemented by studies with experimental animals which provide further guidance on the form of the dose-response relationship for cancer induction, as well as on the effect of dose rate on the tumour yield. The emphasis of the report is on cancer induction resulting from exposure to radiations with a low linear energy transfer (LET). The work was performed under contract for the Institut de Protection et de Surete Nucleaire, Fontenay-aux-Roses, Paris, France, whose agreement to publish is gratefully ackowledged. It extends the advice on radiation risks given in Documents of the NRPB, 4 No. 4 (1993). (Author)

  9. Radiation dosemeters and ambient dose rate measuring systems

    International Nuclear Information System (INIS)

    Maushart, R.

    1985-01-01

    The manufacturers have got the feeling that the PTB only reluctantly accepts complex dosimetric systems or systems with modern digital and microprocessor technology. Especially the fact that the PTB demands a restriction to a defined system configuration which must not be changed after design approval is felt to be a severe handicap. The rigid frame of design qualification forces manufacturers to adopt a two-tier development line, at least for ambient dose rate measuring systems, and frequently it is not necessarily the 'nature' system, i.e. equipment with modern technology, that is sent in to the PTB for testing. The way of solving the problem could be that PTB more readily accepts less familiar technologies, for instance by more frequently approving equipment at least preliminarily or for a restricted period of time, in order to collect experience. Another way could be to grant licence for system components, especially detectors. (orig./HP) [de

  10. Radiation safety program in high dose rate brachytherapy facility at INHS Asvini

    Directory of Open Access Journals (Sweden)

    Kirti Tyagi

    2014-01-01

    Full Text Available Brachytherapy concerns primarily the use of radioactive sealed sources which are inserted into catheters or applicators and placed directly into tissue either inside or very close to the target volume. The use of radiation in treatment of patients involves both benefits and risks. It has been reported that early radiation workers had developed radiation induced cancers. These incidents lead to continuous work for the improvement of radiation safety of patients and personnel The use of remote afterloading equipment has been developed to improve radiation safety in the delivery of treatment in brachytherapy. The widespread adoption of high dose rate brachytherapy needs appropriate quality assurance measures to minimize the risks to both patients and medical staff. The radiation safety program covers five major aspects: quality control, quality assurance, radiation monitoring, preventive maintenance, administrative measures and quality audit. This paper will discuss the radiation safety program developedfor a high dose rate brachytherapy facility at our centre which may serve as a guideline for other centres intending to install a similar facility.

  11. Recovery and permanent radiation damage of plastic scintillators at different dose rates

    International Nuclear Information System (INIS)

    Bicken, B.; Holm, U.; Marckmann, T.; Wick, K.; Rhode, M.

    1990-01-01

    This paper reports on the radiation stability of plastic scintillators and wavelength shifters for the calorimeter of the ZEUS detector by irradiating them with protons, a 60 Co-source, and depleted uranium. Changes in light yield, absorption length and absorption coefficient have been measured for storage in inert and oxygen atmospheres during and after irradiation. Radiation doses up to 40 kGy with dose rates of 30 up to 2000 Gy/h have been applied. The polystyrene based scintillator SCSN-38 and the wavelength shifters Y-7 and K-27 in PMMA show an additional absorption but a recovery in air to a low permanent damage (at 10 kGy) which is proportional to the applied dose. Series investigations on samples of all production cycles of the ZEUS scintillators with high dose rates show only minor differences in radiation hardness. The recovery is described by a simple oxygen diffusion model for high and medium dose rates down to 30 Gy/h. During long term irradiations at low dose rates (<100 Gy/h) of 3 mm thick SCSN-38 in air the radiation damage recovers to a permanent damage which does not depend on the dose rate. On the other hand the radiation damage at very low dose rates (17 Gy/a) seems to be higher than expected for the accumulated dose

  12. A method for radiobiological investigations in radiation fields with different LET and high dose rates

    International Nuclear Information System (INIS)

    Grundler, W.

    1976-01-01

    For investigations: 1. Performed in the field of radiobiology with different LET-radiation and a relatively high background dose rate of one component (e.g. investigations with fast and intermediate reactor neutrons) 2. Concerning radiation risk studies within a wide range 3. Of irradiations, covering a long time period (up to 100 days) a test system is necessary which on the one hand makes it possible to analyze the influence of different LET radiation and secondly shows a relative radiation resistant behaviour and allows a simple cell cycle regulation. A survey is given upon the installed device of a simple cell observation method, the biological test system used and the analysis of effects caused by dose, repair and LET. It is possible to analyze the behaviour of the nonsurvival cells and to demonstrate different reactions of the test parameters to the radiation of different LET. (author)

  13. 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.

  14. 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.

  15. 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

  16. Determination of dose rates in beta radiation fields using extrapolation chamber and GM counter

    DEFF Research Database (Denmark)

    Borg, J.; Christensen, P.

    1995-01-01

    of depth-dose profiles from different beta radiation fields with E(max) values down to 156 keV. Results are also presented from studies of GM counters for use as survey instruments for monitoring beta dose rates at the workplace. Advantages of GM counters are a simple measurement technique and high...... sensitivity. GM responses were measured from exposures in different beta radiation fields using different filters in front of the GM detector and the paper discusses the possibility of using the results from GM measurements with two different filters in an unknown beta radiation field to obtain a value...

  17. Glued versus stapled anastomosis of the colon: An experimental study to determine comparative resistance to intraluminal pressure

    Directory of Open Access Journals (Sweden)

    Jiri Paral

    2014-07-01

    Conclusion: Healing with absorbable synthetic glue was as good as with staples. Glued anastomoses resisted pressures that were statistically significantly higher than physiological intraluminal colon pressures but lower than stapled ones.

  18. Radiation exposure rate and liquid level measurement inside a high level liquid waste (HLLW) storage tank

    International Nuclear Information System (INIS)

    Sur, B.; Yue, S.; Thekkevarriam, A.

    2007-01-01

    An instrument based on an inexpensive, small silicon diode has been developed and used to measure, for the first time, the gamma radiation exposure rate profile inside a 6.4 mm diameter reentrant thermo-well tube, immersed in the highly radioactive liquid solution in an HLLW storage tank. The measurement agrees with previous calculations of exposure rate, and provides confirmation for safe and effective radiation work plans and material selection for investigations and remediation of the storage tank facility. The measured radiation exposure rate profile is also used to confirm that the position of tank internal structures have not changed because of aging and corrosion, and to obtain, within a few mm, the level of liquid inside the tank. (author)

  19. Radiation and Reason Why radiation at modest dose rates is quite harmless and current radiation safety regulations are flawed

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    Data on the impact of ionising radiation on life are examined in the light of evolutionary biology. This comparison confirms that fear of nuclear radiation is not justified by science itself; rather it originates in a failure of public trust in nuclear science, a relic of the international politics of the Cold War era. Current ionisation safety regulations appease this fear but without scientific support and they need fundamental reformulation. This should change the reaction to accidents like Fukushima, the cost of nuclear energy and the application of nuclear technology to the supply of food and fresh water. Such a boost to the world economy would require that more citizens study and appreciate the science involved – and then tell others -- not as much fun as the Higgs, perhaps, but no less important! www.radiationandreason.com

  20. Correlation of radiation dose and heart rate in dual-source computed tomography coronary angiography.

    Science.gov (United States)

    Laspas, Fotios; Tsantioti, Dimitra; Roussakis, Arkadios; Kritikos, Nikolaos; Efthimiadou, Roxani; Kehagias, Dimitrios; Andreou, John

    2011-04-01

    Computed tomography coronary angiography (CTCA) has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but the relatively high radiation dose remains a major concern. To evaluate the relationship between radiation exposure and heart rate (HR), in dual-source CTCA. Data from 218 CTCA examinations, performed with a dual-source 64-slices scanner, were statistically evaluated. Effective radiation dose, expressed in mSv, was calculated as the product of the dose-length product (DLP) times a conversion coefficient for the chest (mSv = DLPx0.017). Heart rate range and mean heart rate, expressed in beats per minute (bpm) of each individual during CTCA, were also provided by the system. Statistical analysis of effective dose and heart rate data was performed by using Pearson correlation coefficient and two-sample t-test. Mean HR and effective dose were found to have a borderline positive relationship. Individuals with a mean HR >65 bpm observed to receive a statistically significant higher effective dose as compared to those with a mean HR ≤65 bpm. Moreover, a strong correlation between effective dose and variability of HR of more than 20 bpm was observed. Dual-source CT scanners are considered to have the capability to provide diagnostic examinations even with high HR and arrhythmias. However, it is desirable to keep the mean heart rate below 65 bpm and heart rate fluctuation less than 20 bpm in order to reduce the radiation exposure.

  1. Isodose mapping of terrestrial gamma radiation dose rate of Selangor state, Kuala Lumpur and Putrajaya, Malaysia

    International Nuclear Information System (INIS)

    Sanusi, M.S.M.; Ramli, A.T.; Gabdo, H.T.; Garba, N.N.; Heryanshah, A.; Wagiran, H.; Said, M.N.

    2014-01-01

    A terrestrial gamma radiation survey for the state of Selangor, Kuala Lumpur and Putrajaya was conducted to obtain baseline data for environmental radiological health practices. Based on soil type, geological background and information from airborne survey maps, 95 survey points statistically representing the study area were determined. The measured doses varied according to geological background and soil types. They ranged from 17 nGy h −1 to 500 nGy h −1 . The mean terrestrial gamma dose rate in air above the ground was 182 ± 81 nGy h −1 . This is two times higher than the average dose rate of terrestrial gamma radiation in Malaysia which is 92 nGy h −1 (UNSCEAR 2000). An isodose map was produced to represent exposure rate from natural sources of terrestrial gamma radiation. - Highlights: • A methodology is presented to reduce terrestrial gamma dose rate field survey. • Geological background of acid intrusive of granitic type has the highest dose rates. • The mean dose rate is 2 times higher than the world average. • Isodose map of terrestrial gamma radiation for Selangor, Kuala Lumpur and Putrajaya was produced

  2. Risk of solid cancer in low dose-rate radiation epidemiological studies and the dose-rate effectiveness factor.

    Science.gov (United States)

    Shore, Roy; Walsh, Linda; Azizova, Tamara; Rühm, Werner

    2017-10-01

    Estimated radiation risks used for radiation protection purposes have been based primarily on the Life Span Study (LSS) of atomic bomb survivors who received brief exposures at high dose rates, many with high doses. Information is needed regarding radiation risks from low dose-rate (LDR) exposures to low linear-energy-transfer (low-LET) radiation. We conducted a meta-analysis of LDR epidemiologic studies that provide dose-response estimates of total solid cancer risk in adulthood in comparison to corresponding LSS risks, in order to estimate a dose rate effectiveness factor (DREF). We identified 22 LDR studies with dose-response risk estimates for solid cancer after minimizing information overlap. For each study, a parallel risk estimate was derived from the LSS risk model using matching values for sex, mean ages at first exposure and attained age, targeted cancer types, and accounting for type of dosimetric assessment. For each LDR study, a ratio of the excess relative risk per Gy (ERR Gy -1 ) to the matching LSS ERR risk estimate (LDR/LSS) was calculated, and a meta-analysis of the risk ratios was conducted. The reciprocal of the resultant risk ratio provided an estimate of the DREF. The meta-analysis showed a LDR/LSS risk ratio of 0.36 (95% confidence interval [CI] 0.14, 0.57) for the 19 studies of solid cancer mortality and 0.33 (95% CI 0.13, 0.54) when three cohorts with only incidence data also were added, implying a DREF with values around 3, but statistically compatible with 2. However, the analyses were highly dominated by the Mayak worker study. When the Mayak study was excluded the LDR/LSS risk ratios increased: 1.12 (95% CI 0.40, 1.84) for mortality and 0.54 (95% CI 0.09, 0.99) for mortality + incidence, implying a lower DREF in the range of 1-2. Meta-analyses that included only cohorts in which the mean dose was LDR data provide direct evidence regarding risk from exposures at low dose rates as an important complement to the LSS risk estimates used

  3. Extrahepatic bile duct carcinoma treated by intraluminal irradiation with iridium-192 wire. Report of a case

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, H; Kuroda, T; Uchida, H [Osaka Univ. (Japan). Faculty of Medicine

    1980-08-01

    A 57-year-old male with obstructive jaundice was diagnosed extrahepatic bile duct carcinoma at bifurcation by percutaneous transhepatic cholangiography (PTC). He was treated 3,300 rad of external irradiation and then intraluminal irradiation using the Iridium-192 wire by two times with the aid of PTC internal drainage, each was given by the dose of 1,600 rad at 5 mm inside the tumor from the PTC-tube. He had been well for about 1 year and then died because of ascites and cachexia. Autopsy revealed only microscopic tumor cells remaining around the common duct below the cystic junction. It was confirmed that intraluminal irradiation using the Iridium-192 wire was potentially curable and easily applicable to the bile duct carcinoma.

  4. Extrahepatic bile duct carcinoma treated by intraluminal irradiation with iridium-192 wire

    International Nuclear Information System (INIS)

    Ikeda, Hiro; Kuroda, Tomosumi; Uchida, Hideo

    1980-01-01

    A 57-year-old male with obstructive jaundice was diagnosed extrahepatic bile duct carcinoma at bifurcation by percutaneous transhepatic cholangiography (PTC). He was treated 3,300 rad of external irradiation and then intraluminal irradiation using the Iridium-192 wire by two times with the aid of PTC internal drainage, each was given by the dose of 1,600 rad at 5 mm inside the tumor from the PTC-tube. He had been well for about 1 year and then died because of ascites and cachexia. Autopsy revealed only microscopic tumor cells remaining around the common duct below the cystic junction. It was confirmed that intraluminal irradiation using the Iridium-192 wire was potentially curable and easily applicable to the bile duct carcinoma. (author)

  5. Survey of environmental radiation dose rates in Kyoto and Shiga prefectures, Japan

    International Nuclear Information System (INIS)

    Minamia, Kazuyuki; Shimo, Michikuni; Oka, Mitsuaki; Ejiri, Kazutaka; Sugino, Masato; Minato, Susumu; Hosoda, Masahiro; Yamada, Junya; Fukushi, Masahiro

    2008-01-01

    We have measured environmental radiation dose rates in several Prefectures, such as Ai chi Prefecture, Gifu Prefecture, and Mie Prefecture, in central Japan. Recently, we measured the environmental radiation dose rates in Kyoto and Shiga Prefectures that are also located in central Japan with a car-borne survey system. At the time of measurement, Kyoto Prefecture (area: 4,613 km 2 ) had a total of 36 districts, and Shiga Prefecture (area: 3,387 km 2 ) a total of 26. Terrestrial gamma ray dose rates and secondary cosmic ray dose rates were measured by a 2 inches ψ x 2 inches NaI(Tl) scintillation counter and a handy-type altimeter (GPS eTrex Legend by Gamin), respectively. The following factors were taken into consideration the shielding effect of the car body, the effect of the road pavement, radon progeny borne by precipitation, and increases in tunnels and near the walls. Terrestrial gamma ray dose rates in Kyoto and Shiga Prefectures were estimated to be 51.7 ± 6.0 n Gy/h (district average: 52.4 ± 4.7 n Gy/h), 52.2 ± 10.5 n Gy/h (district average: 51.9 ± 8.1 n Gy/h), respectively. Secondary cosmic ray dose rates in Kyoto and Shiga Prefectures were 30.0 ± 0.6 n Gy/h (district average: 29.9 ±0.3 n Gy/h), 30.1 ± 0.3 n Gy/h (district average: 30.0 ± 0.2 n Gy/h), respectively. The environmental radiation dose rates due to the sum dose rates of terrestrial gamma ray and secondary cosmic ray in Kyoto and Shiga Prefectures were 81.7 ± 6.2 n Gy/h (district average: 82.3 ± 4.8 n Gy/h), 82.3 ± 10.6 n Gy/h (district average: 82.0 ± 8.1 n Gy/h), respectively. We confirmed that the environmental radiation dose rates in Kyoto and Shiga Prefectures mainly depended on the change of the terrestrial gamma ray dose rates, since the secondary cosmic ray dose rates had little change. Therefore, radiation dose-rate maps of the terrestrial gamma rays as well as maps of the environmental radiation dose-rate were drawn. (author)

  6. Pretreatment Growth Rate Predicts Radiation Response in Vestibular Schwannomas

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Nina N. [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); Harvard Medical School, Department of Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Niemierko, Andrzej [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); Larvie, Mykol [Harvard Medical School, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts (United States); Curtin, Hugh [Harvard Medical School, Department of Radiology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Loeffler, Jay S. [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); McKenna, Michael J. [Harvard Medical School, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Shih, Helen A., E-mail: hshih@partners.org [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-05-01

    Purpose: Vestibular schwannomas (VS) are often followed without initial therapeutic intervention because many tumors do not grow and radiation therapy is associated with potential adverse effects. In an effort to determine whether maximizing initial surveillance predicts for later treatment response, the predictive value of preirradiation growth rate of VS on response to radiation therapy was assessed. Methods and Materials: Sixty-four patients with 65 VS were treated with single-fraction stereotactic radiation surgery or fractionated stereotactic radiation therapy. Pre- and postirradiation linear expansion rates were estimated using volumetric measurements on sequential magnetic resonance images (MRIs). In addition, postirradiation tumor volume change was classified as demonstrating shrinkage (ratio of volume on last follow-up MRI to MRI immediately preceding irradiation <80%), stability (ratio 80%-120%), or expansion (ratio >120%). The median pre- and postirradiation follow-up was 20.0 and 27.5 months, respectively. Seven tumors from neurofibromatosis type 2 (NF2) patients were excluded from statistical analyses. Results: In the 58 non-NF2 patients, there was a trend of correlation between pre- and postirradiation volume change rates (slope on linear regression, 0.29; P=.06). Tumors demonstrating postirradiation expansion had a median preirradiation growth rate of 89%/year, and those without postirradiation expansion had a median preirradiation growth rate of 41%/year (P=.02). As the preirradiation growth rate increased, the probability of postirradiation expansion also increased. Overall, 24.1% of tumors were stable, 53.4% experienced shrinkage, and 22.5% experienced expansion. Predictors of no postirradiation tumor expansion included no prior surgery (P=.01) and slower tumor growth rate (P=.02). The control of tumors in NF2 patients was only 43%. Conclusions: Radiation therapy is an effective treatment for VS, but tumors that grow quickly preirradiation may be

  7. Nuclear Radiation Degradation Study on HD Camera Based on CMOS Image Sensor at Different Dose Rates

    Directory of Open Access Journals (Sweden)

    Congzheng Wang

    2018-02-01

    Full Text Available In this work, we irradiated a high-definition (HD industrial camera based on a commercial-off-the-shelf (COTS CMOS image sensor (CIS with Cobalt-60 gamma-rays. All components of the camera under test were fabricated without radiation hardening, except for the lens. The irradiation experiments of the HD camera under biased conditions were carried out at 1.0, 10.0, 20.0, 50.0 and 100.0 Gy/h. During the experiment, we found that the tested camera showed a remarkable degradation after irradiation and differed in the dose rates. With the increase of dose rate, the same target images become brighter. Under the same dose rate, the radiation effect in bright area is lower than that in dark area. Under different dose rates, the higher the dose rate is, the worse the radiation effect will be in both bright and dark areas. And the standard deviations of bright and dark areas become greater. Furthermore, through the progressive degradation analysis of the captured image, experimental results demonstrate that the attenuation of signal to noise ratio (SNR versus radiation time is not obvious at the same dose rate, and the degradation is more and more serious with increasing dose rate. Additionally, the decrease rate of SNR at 20.0, 50.0 and 100.0 Gy/h is far greater than that at 1.0 and 10.0 Gy/h. Even so, we confirm that the HD industrial camera is still working at 10.0 Gy/h during the 8 h of measurements, with a moderate decrease of the SNR (5 dB. The work is valuable and can provide suggestion for camera users in the radiation field.

  8. Pretreatment Growth Rate Predicts Radiation Response in Vestibular Schwannomas

    International Nuclear Information System (INIS)

    Niu, Nina N.; Niemierko, Andrzej; Larvie, Mykol; Curtin, Hugh; Loeffler, Jay S.; McKenna, Michael J.; Shih, Helen A.

    2014-01-01

    Purpose: Vestibular schwannomas (VS) are often followed without initial therapeutic intervention because many tumors do not grow and radiation therapy is associated with potential adverse effects. In an effort to determine whether maximizing initial surveillance predicts for later treatment response, the predictive value of preirradiation growth rate of VS on response to radiation therapy was assessed. Methods and Materials: Sixty-four patients with 65 VS were treated with single-fraction stereotactic radiation surgery or fractionated stereotactic radiation therapy. Pre- and postirradiation linear expansion rates were estimated using volumetric measurements on sequential magnetic resonance images (MRIs). In addition, postirradiation tumor volume change was classified as demonstrating shrinkage (ratio of volume on last follow-up MRI to MRI immediately preceding irradiation <80%), stability (ratio 80%-120%), or expansion (ratio >120%). The median pre- and postirradiation follow-up was 20.0 and 27.5 months, respectively. Seven tumors from neurofibromatosis type 2 (NF2) patients were excluded from statistical analyses. Results: In the 58 non-NF2 patients, there was a trend of correlation between pre- and postirradiation volume change rates (slope on linear regression, 0.29; P=.06). Tumors demonstrating postirradiation expansion had a median preirradiation growth rate of 89%/year, and those without postirradiation expansion had a median preirradiation growth rate of 41%/year (P=.02). As the preirradiation growth rate increased, the probability of postirradiation expansion also increased. Overall, 24.1% of tumors were stable, 53.4% experienced shrinkage, and 22.5% experienced expansion. Predictors of no postirradiation tumor expansion included no prior surgery (P=.01) and slower tumor growth rate (P=.02). The control of tumors in NF2 patients was only 43%. Conclusions: Radiation therapy is an effective treatment for VS, but tumors that grow quickly preirradiation may be

  9. Nuclear Radiation Degradation Study on HD Camera Based on CMOS Image Sensor at Different Dose Rates.

    Science.gov (United States)

    Wang, Congzheng; Hu, Song; Gao, Chunming; Feng, Chang

    2018-02-08

    In this work, we irradiated a high-definition (HD) industrial camera based on a commercial-off-the-shelf (COTS) CMOS image sensor (CIS) with Cobalt-60 gamma-rays. All components of the camera under test were fabricated without radiation hardening, except for the lens. The irradiation experiments of the HD camera under biased conditions were carried out at 1.0, 10.0, 20.0, 50.0 and 100.0 Gy/h. During the experiment, we found that the tested camera showed a remarkable degradation after irradiation and differed in the dose rates. With the increase of dose rate, the same target images become brighter. Under the same dose rate, the radiation effect in bright area is lower than that in dark area. Under different dose rates, the higher the dose rate is, the worse the radiation effect will be in both bright and dark areas. And the standard deviations of bright and dark areas become greater. Furthermore, through the progressive degradation analysis of the captured image, experimental results demonstrate that the attenuation of signal to noise ratio (SNR) versus radiation time is not obvious at the same dose rate, and the degradation is more and more serious with increasing dose rate. Additionally, the decrease rate of SNR at 20.0, 50.0 and 100.0 Gy/h is far greater than that at 1.0 and 10.0 Gy/h. Even so, we confirm that the HD industrial camera is still working at 10.0 Gy/h during the 8 h of measurements, with a moderate decrease of the SNR (5 dB). The work is valuable and can provide suggestion for camera users in the radiation field.

  10. Positive intraluminal bowel contrast on computed tomography following oral ingestion of Kayexelate

    International Nuclear Information System (INIS)

    Zissin, R.; Stackievicz, R.; Osadchy, A.; Gayer, G.

    2008-01-01

    Our study presents the computed tomography (CT) manifestations of orally ingested kayexelate (a powdered form of sodium polystyrene sulphonate) used to treat hyperkalemia. Five patients with whom kayexelate appeared as high-attenuating intraluminal enteric content, similar to oral contrast material or leakage of intravascular contrast, are reported. Radiologists should be familiar with its appearance as it may mimic oral or vascular contrast within the gastrointestinal tract, a finding that may lead to a diagnostic error or misinterpretation. (author)

  11. Intraluminal duodenal diverticulum: CT and gadoxetic acid-enhanced MRI findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Myeong; Lee, Nam Kyung; Kim, Suk; Kim, Dong Uk; Kim, Tae Un [Dept. of Radiology, Pusan National University Hospital, Pusan National University School of Medicine, Busan (Korea, Republic of)

    2015-03-15

    Intraluminal duodenal diverticulum (IDD) is a rare congenital anomaly. IDD can become symptomatic in 20% to 25% of cases when complicated by intestinal obstruction, pancreatitis, or hemorrhage. We report the case of a 21-year-old female presenting with IDD mimicking duodenoduodenal intussusception. We describe the imaging features of IDD on the gadoxetic acid-enhanced magnetic resonance image as well as computed tomography.

  12. Experimental study of radiation dose rate at different strategic points of the BAEC TRIGA Research Reactor.

    Science.gov (United States)

    Ajijul Hoq, M; Malek Soner, M A; Salam, M A; Haque, M M; Khanom, Salma; Fahad, S M

    2017-12-01

    The 3MW TRIGA Mark-II Research Reactor of Bangladesh Atomic Energy Commission (BAEC) has been under operation for about thirty years since its commissioning at 1986. In accordance with the demand of fundamental nuclear research works, the reactor has to operate at different power levels by utilizing a number of experimental facilities. Regarding the enquiry for safety of reactor operating personnel and radiation workers, it is necessary to know the radiation level at different strategic points of the reactor where they are often worked. In the present study, neutron, beta and gamma radiation dose rate at different strategic points of the reactor facility with reactor power level of 2.4MW was measured to estimate the rising level of radiation due to its operational activities. From the obtained results high radiation dose is observed at the measurement position of the piercing beam port which is caused by neutron leakage and accordingly, dose rate at the stated position with different reactor power levels was measured. This study also deals with the gamma dose rate measurements at a fixed position of the reactor pool top surface for different reactor power levels under both Natural Convection Cooling Mode (NCCM) and Forced Convection Cooling Mode (FCCM). Results show that, radiation dose rate is higher for NCCM in compared with FCCM and increasing with the increase of reactor power. Thus, concerning the radiological safety issues for working personnel and the general public, the radiation dose level monitoring and the experimental analysis performed within this paper is so much effective and the result of this work can be utilized for base line data and code verification of the nuclear reactor. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Low dose rate radiation favors apoptosis as a mechanism of cell death

    International Nuclear Information System (INIS)

    Murtha, Albert D.; Rupnow, Brent; Knox, Susan J.

    1997-01-01

    Purpose/Objective: Radioimmunotherapy (RIT) has demonstrated promising results in the treatment of chemotherapy refractory non-Hodgkin's lymphoma. The radiation associated with this therapy is emitted in a continuous fashion at low dose rates (LDR). Results from studies comparing the relative efficacy of LDR radiation and high dose rate (HDR) radiation on malignant cell killing have been variable. This variability may be due in part to the relative contribution of different mechanisms of cell killing (apoptosis or necrosis) at different dose rates. Materials and Methods: In order to test this hypothesis, the relative efficacy of LDR (16.7 cGy/hr) and HDR radiation (422 cGy/min) were compared using a human B cell lymphoma cell line (PW) and a PW clone (c26) stably transfected to overexpress the anti-apoptotic gene Bcl-2. The endpoints evaluated included the relative amount of cell killing, the fraction of cell killing attributable to apoptosis versus necrosis, and the impact of Bcl-2 overexpression on both overall cell killing and the fraction of killing attributable to apoptosis. Results: HDR and LDR radiation resulted in similar overall cell killing in the PW wild type cell line. In contrast, killing of clone c26 cells was dose rate dependent. One third less killing was seen following LDR irradiation of c26 cells compared with equivalent doses of HDR radiation. Analysis of the relative mechanisms of killing following LDR irradiation revealed a relative increase in the proportion of killing attributable to apoptosis. Conclusion: These findings support the hypothesis that in PW cells, LDR radiation appears to be highly dependent on apoptosis as a mechanism of cell death. These findings may have implications for the selection of patients for RIT, and for the treatment of tumors that overexpress Bcl-2. They may also help form the basis for future rational design of effective combined modality therapies utilizing RIT

  14. Intraluminal polyethylene glycol stabilizes tight junctions and improves intestinal preservation in the rat.

    Science.gov (United States)

    Oltean, M; Joshi, M; Björkman, E; Oltean, S; Casselbrant, A; Herlenius, G; Olausson, M

    2012-08-01

    Rapidly progressing mucosal breakdown limits the intestinal preservation time below 10 h. Recent studies indicate that intraluminal solutions containing polyethylene glycol (PEG) alleviate preservation injury of intestines stored in UW-Viaspan. We investigated whether a low-sodium PEG solution is beneficial for intestines stored in histidine-tryptophane-ketoglutarate (HTK) preservation solution. Rat intestines used as control tissue (group 1) were perfused with HTK, groups 2 and 3 received either a customized PEG-3350 (group 2) or an electrolyte solution (group 3) intraluminally before cold storage. Tissue injury, brush-border maltase activity, zonula occludens-1 (ZO-1) and claudin-3 expression in the tight junctions (TJ) were analyzed after 8, 14 and 20 h. We measured epithelial resistance and permeability (Ussing chamber) after 8 and 14 h. Group 2 had superior morphology while maltase activity was similar in all groups. TJ proteins rapidly decreased and decolocalized in groups 1 3; these negative events were delayed in group 2, where colocalization persisted for about 14 h. Intestines in group 2 had higher epithelial resistance and lower permeability than the other groups. These results suggest that a customized PEG solution intraluminally reduces the intestinal preservation injury by improving several major epithelial characteristics without negatively affecting the brush-border enzymes or promoting edema. © Copyright 2012 The American Society of Transplantation and the American Society of Transplant Surgeons.

  15. Atg9 is required for intraluminal vesicles in amphisomes and autolysosomes

    Directory of Open Access Journals (Sweden)

    C. A. Bader

    2015-11-01

    Full Text Available Autophagy is an intracellular recycling and degradation process, which is important for energy metabolism, lipid metabolism, physiological stress response and organism development. During Drosophila development, autophagy is up-regulated in fat body and midgut cells, to control metabolic function and to enable tissue remodelling. Atg9 is the only transmembrane protein involved in the core autophagy machinery and is thought to have a role in autophagosome formation. During Drosophila development, Atg9 co-located with Atg8 autophagosomes, Rab11 endosomes and Lamp1 endosomes-lysosomes. RNAi silencing of Atg9 reduced both the number and the size of autophagosomes during development and caused morphological changes to amphisomes/autolysosomes. In control cells there was compartmentalised acidification corresponding to intraluminal Rab11/Lamp-1 vesicles, but in Atg9 depleted cells there were no intraluminal vesicles and the acidification was not compartmentalised. We concluded that Atg9 is required to form intraluminal vesicles and for localised acidification within amphisomes/autolysosomes, and consequently when depleted, reduced the capacity to degrade and remodel gut tissue during development.

  16. Estimation of daily flow rate of photovoltaic water pumping systems using solar radiation data

    Directory of Open Access Journals (Sweden)

    M. Benghanem

    2018-03-01

    Full Text Available This paper presents a simple model which allows us to contribute in the studies of photovoltaic (PV water pumping systems sizing. The nonlinear relation between water flow rate and solar power has been obtained experimentally in a first step and then used for performance prediction. The model proposed enables us to simulate the water flow rate using solar radiation data for different heads (50 m, 60 m, 70 m and 80 m and for 8S × 3P PV array configuration. The experimental data are obtained with our pumping test facility located at Madinah site (Saudi Arabia. The performances are calculated using the measured solar radiation data of different locations in Saudi Arabia. Knowing the solar radiation data, we have estimated with a good precision the water flow rate Q in five locations (Al-Jouf, Solar Village, AL-Ahsa, Madinah and Gizan in Saudi Arabia. The flow rate Q increases with the increase of pump power for different heads following the nonlinear model proposed. Keywords: Photovoltaic water pumping system, Solar radiation data, Simulation, Flow rate

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-15

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

  18. External exposure rates from terrestrial radiation at Guarapari and Meaipe in Brazil

    International Nuclear Information System (INIS)

    Fujinami, N.; Koga, T.; Morishima, H.

    2000-01-01

    Recently epidemiological and cytogenetic studies on inhabitants living in high background radiation areas have been carried out in order to examine health effects of exposure to low dose radiation. Guarapari and Meaipe are towns built on the monazite sand region along the Atlantic coast in Brazil, which is one of the widely known high background radiation areas in the world. As an initial step toward studies on health effects of high background radiation on inhabitants living in Guarapari and Meaipe, we surveyed absorbed dose rates in air in these towns with a portable NaI(Tl) scintillation detector in September 1998. Sand and soil were also sampled there so as to determine the concentrations of Th-232 and Ra-226 in them. In Guarapari and Meaipe, dose rates in the streets ranged from 0.1 to 0.4 μ Gy/h except for a few places such as near the Areia Preta beach and Meaipe beach. Dose rates inside houses were lower than 0.2 μ Gy/h except that two houses attained a dose rate of 0.4 μ Gy/h. Our effective dose rate from external terrestrial irradiation (outdoors and indoors) was 0.17 μ Sv/h on the average, during the period of our three day stay in Guarapari and Meaipe. From comparison of our present values with those observed in the 1960s, which were cited in UNSCEAR reports, it is indicated that dose rate levels have decreased clearly in downtown, while the levels have scarcely changed in beaches and unpaved beach streets which have not been developed yet. This fact suggests that the natural radiation environment of Guarapari and Meaipe has varied with urbanization which brought paved streets, and changes in the structure and building materials of houses. A detailed survey is necessary in order to evaluate present absorbed dose rates in air in this area. (author)

  19. Radiation-thermal degradation of PE and PVC: Mechanism of synergism and dose rate effects

    Science.gov (United States)

    Clough, Roger L.; Gillen, Kenneth T.

    Polyethylene insulation and polyvinyl chloride jacketing materials that had been in use in a nuclear application were recently found to be substantially deteriorated. The damage had occurred under conditions where both the total estimated dose (about 2.5 Mrad) and the operating temperatures (about 43°C average) seemed relatively moderate. These results prompted us to initiate a program to study polyvinyl chloride and polyethylene degradation under conditions of combined γ-radiation and elevated temperature environments. A number of interesting aging effects were observed, including 1) a striking synergism between radiation and temperature and 2) strong dose-rate dependent effects which occur over a wide range of dose rates. The aging effects are explained in terms of a chain branching degradation mechanism involving thermally induced breakdown of peroxides which are formed in reactions initiated by the radiation. Evidence for this mechanism is derived from infrared spectra, from sequential radiation-elevated temperature experiments including experiments under inert atmosphere, from activation energy estimates and from a new technique involving treatment of intact samples with PH 3 for chemical reduction of peroxides. The results of our studies raise significant doubts about the utility of earlier compilations which purportedly serve as radiation life expectancy guides by indicating "tolerable radiation doses" for a variety of polymers.

  20. Dose rate effect models for biological reaction to ionizing radiation in human cell lines

    International Nuclear Information System (INIS)

    Magae, Junji; Ogata, Hiromitsu

    2008-01-01

    Full text: Because of biological responses to ionizing radiation are dependent on irradiation time or dose rate as well as dose, simultaneous inclusion of dose and dose rate is required to evaluate the risk of long term irradiation at low dose rates. We previously published a novel statistical model for dose rate effect, modified exponential (MOE) model, which predicts irradiation time-dependent biological response to low dose rate ionizing radiation, by analyzing micronucleus formation and growth inhibition in a human osteosarcoma cell line, exposed to wide range of doses and dose rates of gamma-rays. MOE model demonstrates that logarithm of median effective dose exponentially increases in low dose rates, and thus suggests that the risk approaches to zero at infinitely low dose rate. In this paper, we extend the analysis in various kinds of human cell lines exposed to ionizing radiation for more than a year. We measured micronucleus formation and [ 3 H]thymidine uptake in human cell lines including an osteosarcoma, a DNA-dependent protein kinase-deficient glioma, a SV40-transformed fibroblast derived from an ataxia telangiectasia patient, a normal fibroblast, and leukemia cell lines. Cells were exposed to gamma-rays in irradiation room bearing 50,000 Ci of cobalt-60. After the irradiation, they were cultured for 24 h in the presence of cytochalasin B to block cytokinesis, and cytoplasm and nucleus were stained with DAPI and prospidium iodide. The number of binuclear cells bearing a micronucleus was counted under a fluorescence microscope. For proliferation inhibition, cells were cultured for 48 h after the irradiation and [ 3 H] thymidine was pulsed for 4 h before harvesting. We statistically analyzed the data for quantitative evaluation of radiation risk. While dose and dose rate relationship cultured within one month followed MOE model in cell lines holding wild-type DNA repair system, dose rate effect was greatly impaired in DNA repair-deficient cell lines

  1. Palliation of recurrent esophageal cancer after definitive radiotherapy with intraluminal brachytherapy. A preliminary report

    International Nuclear Information System (INIS)

    Chen, Shang-Wen; Shiau, An-Cheng; Liang, Ji-An; Yang, Shih-Neng; Lin, Fang-Jen

    2004-01-01

    The objective was to assess the feasibility, toxicity, and efficacy of palliative intraluminal brachytherapy (ILBT) for recurrent esophageal cancer after definitive radiotherapy. From January 2000 to December 2002, 10 consecutive patients with recurrent esophageal cancer after definitive radiotherapy completed allocated ILBT, were enrolled into the analysis. All patients presented with a World Health Organization (WHO) dysphagia score III or more (III: 7; IV: 3). The ILBT was delivered with a special assembled applicator composed of three layers of plastic tubes, inserted transorally. The active treatment length of ILBT was defined as the site of recurrent esophageal tumor plus 1 cm each from the proximal and distal margins. The ILBT was performed by high-dose-rate iridium-192 remote after-loading technique. The ILBT consisted of 2 to 4 fractions of 3 Gy at 1-week intervals. The prescribed dose was specified at a 1 cm depth from the mid-dwell position and the dosimetry was calculated using computer-based software. Patients were followed up monthly and assessed for relief of dysphagia and development of complications. All patients completed the allocated ILBT schedule. Eight patients died (2 from distant metastasis; 3 from respiratory failure by tumor invasion; 2 from aspiration pneumonia; 1 from chemotherapy-induced sepsis). The median survival of the 10 patients was 5 months (range 2 to 32), and the estimated 1-year actuarial survival was 24%. Time to recurrence of more than 3 months was the only prognostic factor for longer survival (p=0.01). When the response of ILBT was assessed one month after treatment, eight patients achieved improvement of dysphagia, while two patients got worse. The median dysphagia progression-free interval (DPFI) of the 8 responders was 3 months (range 2 to 7). The predictive parameter for good ILBT response was an initial dysphagia score (p=0.01). Only one patient developed tracheo-esophageal fistula 3 months after ILBT. Fractionated

  2. The analogy research study on gamma radiation dose rate of radioisotopes 131Ba and 131I

    International Nuclear Information System (INIS)

    Hu Youhua; Feng Guangwen

    2013-01-01

    Analogy is a inference method ,according some properties of a class of things to inferring the similar things should also have the similar properties. The analogy of same radionuclides is widely used in radioisotope logging environment impact assessment so far. This paper is to provide fFor future providing a theoretical calculation method and analogy method between different radionuclides in radioisotope logging environment impact assessment. In this paper, using the latest decay scheme, through theoretical modeling, the aim is the the establishment of 131 Ba and 131 I radioisotopes gamma radiation dose rate calculation method, and try to carry out analogy research on gamma radiation dose rate of different radioisotopes with the same activity. The results show that the analogy of different radionuclides is feasible, which provides the new method reference for carrying out such radiation environmental impact assessment in future. (authors)

  3. Terrestrial gamma radiation dose rate in Ryukyu Islands, subtropical region of Japan

    International Nuclear Information System (INIS)

    Furukawa, M.; Shiroma, M.; Motomura, D.; Fujioka, S.; Kawakami, T.; Yasuda, Y.; Arakawa, K.; Fukahori, K.; Jyunicho, M.; Ishikawa, S.; Ohomoto, T.; Kina, S.; Shiroma, Y.; Masuda, N.; Hiraoka, H.; Shingaki, R.; Akata, N.; Zhuo, W.; Tokonami, S.

    2015-01-01

    In order to explain the distribution of natural radiation level in the Asia, in situ measurements of dose rate in air due to terrestrial gamma radiation have been conducted in a total of 21 islands that belong to Ryukyu Islands (Ryukyu Archipelago), subtropical rejoin of southwest Japan. Car-borne surveys have also been carried out in Okinawa-jima, the biggest island of the archipelago. Based on the results for these measurements, arithmetic mean, the maximum and the minimum of the dose rates at 1 m in height from the unpaved soil ground in the archipelago were estimated to be 47, 165 and 8 nGy h -1 , respectively. A comparative study of car-borne data obtained prior to and subsequent to the 2011 Fukushima nuclear accident, as for Okinawa-jima, indicated that the nuclear accident has no impact on the environmental radiation at the present time. (authors)

  4. Remote Sensing of Radiation Dose Rate by Customizing an Autonomous Robot

    International Nuclear Information System (INIS)

    Kobayashi, T; Nakahara, M; Morisato, K; Takashina, T; Kanematsu, H

    2012-01-01

    Distribution of radiation dose was measured by customizing an autonomous cleaning robot 'Roomba' and a scintillation counter. The robot was used as a vehicle carrying the scintillation survey meter, and was additionally equipped with an H8 micro computer to remote-control the vehicle and to send measured data. The data obtained were arranged with position data, and then the distribution map of the radiation dose rate was produced. Manual, programmed and autonomous driving tests were conducted, and all performances were verified. That is, for each operational mode, the measurements both with moving and with discrete moving were tried in and outside of a room. Consequently, it has been confirmed that remote sensing of radiation dose rate is possible by customizing a robot on market.

  5. Monitoring of dose rates and radiation flux density in working rooms

    International Nuclear Information System (INIS)

    Krajtor, S.N.

    1980-01-01

    The problems of determining the neutron field characteristics (dose equivalent rate and flux density) in relation to the environmental monitoring by radiation protection services. The measurement devices used for measuring dose equivalent rate and neutron flux density RUS-U8 multi-purpose scintillation radiometer and RUP-1 multi-purpose transportable radiometer as well as measurement technique are described. Recommendations are given for checking measuring devices calibration, registering measurement results [ru

  6. The correlation schemes in calculations of the rate constants of some radiation chemical reactions

    International Nuclear Information System (INIS)

    Zagorets, P.A.; Shostenko, A.G.; Kim, V.

    1983-01-01

    The various correlation relationships of the evaluation of the rate constants of radiation chemical reactions of addition, abstraction and isomerization were considered. It was shown that neglection of the influence of solvent can result in errors in calculations of rate constants equalling two orders in magnitude. Several examples of isokinetic relationship are given. The methods of calculation of transmission coefficient of reaction addition have been discussed. (author)

  7. Modified Exponential (MOE) Models: statistical Models for Risk Estimation of Low dose Rate Radiation

    International Nuclear Information System (INIS)

    Ogata, H.; Furukawa, C.; Kawakami, Y.; Magae, J.

    2004-01-01

    Simultaneous inclusion of dose and dose-rate is required to evaluate the risk of long term irradiation at low dose-rates, since biological responses to radiation are complex processes that depend both on irradiation time and total dose. Consequently, it is necessary to consider a model including cumulative dose,dose-rate and irradiation time to estimate quantitative dose-response relationship on the biological response to radiation. In this study, we measured micronucleus formation and (3H) thymidine uptake in U2OS, human osteosarcoma cell line, as indicators of biological response to gamma radiation. Cells were exposed to gamma ray in irradiation room bearing 50,000 Ci 60Co. After irradiation, they were cultured for 24h in the presence of cytochalasin B to block cytokinesis, and cytoplasm and nucleus were stained with DAPI and propidium iodide. The number of binuclear cells bearing a micronucleus was counted under a florescence microscope. For proliferation inhibition, cells were cultured for 48 h after the irradiation and (3h) thymidine was pulsed for 4h before harvesting. We statistically analyzed the data for quantitative evaluation of radiation risk at low dose/dose-rate. (Author)

  8. Nested radiations and the pulse of angiosperm diversification: increased diversification rates often follow whole genome duplications.

    Science.gov (United States)

    Tank, David C; Eastman, Jonathan M; Pennell, Matthew W; Soltis, Pamela S; Soltis, Douglas E; Hinchliff, Cody E; Brown, Joseph W; Sessa, Emily B; Harmon, Luke J

    2015-07-01

    Our growing understanding of the plant tree of life provides a novel opportunity to uncover the major drivers of angiosperm diversity. Using a time-calibrated phylogeny, we characterized hot and cold spots of lineage diversification across the angiosperm tree of life by modeling evolutionary diversification using stepwise AIC (MEDUSA). We also tested the whole-genome duplication (WGD) radiation lag-time model, which postulates that increases in diversification tend to lag behind established WGD events. Diversification rates have been incredibly heterogeneous throughout the evolutionary history of angiosperms and reveal a pattern of 'nested radiations' - increases in net diversification nested within other radiations. This pattern in turn generates a negative relationship between clade age and diversity across both families and orders. We suggest that stochastically changing diversification rates across the phylogeny explain these patterns. Finally, we demonstrate significant statistical support for the WGD radiation lag-time model. Across angiosperms, nested shifts in diversification led to an overall increasing rate of net diversification and declining relative extinction rates through time. These diversification shifts are only rarely perfectly associated with WGD events, but commonly follow them after a lag period. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  9. Influence of mobility and annihilation of forest dislocations on radiation creep rate of metals

    International Nuclear Information System (INIS)

    Pyatiletov, Yu.S.; Tyupkina, O.G.

    1988-01-01

    Dependence of radiation creep rate ε of metals on stress σ is calculated. It is established that account of mobility and annihilation of 'forest' dislocations leads to the increase of calculational value ε and the effect increases with the growth of σ, reaching 10-15% at σ ∼ 0.8 σ cr (σ cr - critical shear stress)

  10. On the radiative corrections α2lnα to the positronium decay rate

    International Nuclear Information System (INIS)

    Khriplovich, I.B.; Elkhovskij, A.S.

    1990-01-01

    The radiative corrections ∼α 2 ln α to the positronium decay rate are calculated in the Breit approximation which is shown to be quite adequate for the problem. For orthopositronium the result coincides with the previous one, for parapositronium it differs from the old results. 9 refs

  11. Geological influence on terrestrial gamma radiation dose rate in the Malaysian State of Johore

    International Nuclear Information System (INIS)

    Ramli, A.T.; Hussein, A.W.M.A.; Lee, M.H.

    2001-01-01

    Measurements of environmental terrestrial gamma radiation dose-rate (TGRD) have been made in Johore, Malaysia. The focus is on determining a relationship between geological type and TGRD levels. Data were compared using the one way analysis of variance (ANOVA), in some instances revealing significant differences between TGRD measurements and the underlying geological structure

  12. Calculation of radiation dose rate arisen from radionuclide contained in building materials

    International Nuclear Information System (INIS)

    Lai Tien Thinh; Nguyen Hao Quang

    2008-01-01

    This paper presents some results that we used MCNP5 program to calculate radiation dose rate arisen from radionuclide in building materials. Since then, the limits of radionuclide content in building materials are discussed. The calculation results by MCNP are compared with those calculated by analytical method. (author)

  13. Rates of change in natural and anthropogenic radiative forcing over the past 20,000 years.

    Science.gov (United States)

    Joos, Fortunat; Spahni, Renato

    2008-02-05

    The rate of change of climate codetermines the global warming impacts on natural and socioeconomic systems and their capabilities to adapt. Establishing past rates of climate change from temperature proxy data remains difficult given their limited spatiotemporal resolution. In contrast, past greenhouse gas radiative forcing, causing climate to change, is well known from ice cores. We compare rates of change of anthropogenic forcing with rates of natural greenhouse gas forcing since the Last Glacial Maximum and of solar and volcanic forcing of the last millennium. The smoothing of atmospheric variations by the enclosure process of air into ice is computed with a firn diffusion and enclosure model. The 20th century increase in CO(2) and its radiative forcing occurred more than an order of magnitude faster than any sustained change during the past 22,000 years. The average rate of increase in the radiative forcing not just from CO(2) but from the combination of CO(2), CH(4), and N(2)O is larger during the Industrial Era than during any comparable period of at least the past 16,000 years. In addition, the decadal-to-century scale rate of change in anthropogenic forcing is unusually high in the context of the natural forcing variations (solar and volcanoes) of the past millennium. Our analysis implies that global climate change, which is anthropogenic in origin, is progressing at a speed that is unprecedented at least during the last 22,000 years.

  14. Grazing rates of Calanus finmarchicus on Thalassiosira weissflogii cultured under different levels of ultraviolet radiation.

    Directory of Open Access Journals (Sweden)

    David M Fields

    Full Text Available UVB alters photosynthetic rate, fatty acid profiles and morphological characteristics of phytoplankton. Copepods, important grazers of primary production, select algal cells based upon their size, morphological traits, nutritional status, and motility. We investigated the grazing rates of the copepod Calanus finmarchicus on the diatom Thalassiosira weissflogii cultured under 3 levels of ultraviolet radiation (UVR: photosynthetically active radiation (PAR only (4 kJ-m(-2/day, and PAR supplemented with UVR radiation at two intensities (24 kJ-m(-2/day and 48 kJ-m(-2/day. There was no significant difference in grazing rates between the PAR only treatment and the lower UVR treatment. However, grazing rates were significantly (∼66% higher for copepods feeding on cells treated with the higher level of UVR. These results suggest that a short-term increase in UVR exposure results in a significant increase in the grazing rate of copepods and, thereby, potentially alters the flow rate of organic matter through this component of the ecosystem.

  15. Calculation of radiation dose rates from a spent nuclear fuel shipping cask

    International Nuclear Information System (INIS)

    Chen, S.Y.; Yuan, Y.C.

    1988-01-01

    Radiation doses from a spent nuclear fuel cask are usually from various phases of operations during handling, shipping, and storage of the casks. Assessment of such doses requires knowledge of external radiation dose rates at various locations surrounding a cask. Under current practices, dose rates from gamma photons are usually estimated by means of point- or line-source approaches incorporating the conventional buildup factors. Although such simplified approaches may at times be easy to use, their accuracy has not been verified. For example, those simplified methods have not taken into account influencing factors such as the geometry of the cask and the presence of the ground surface, and the effects of these factors on the calculated dose rates are largely unknown. Moreover, similar empirical equations for buildup factors currently do not exist for neutrons. The objective of this study is to use a more accurate approach in calculating radiation dose rates for both neutrons and gamma photons from a spent fuel cask. The calculation utilizes the more sophisticated transport method and takes into account the geometry of the cask and the presence of the ground surface. The results of a detailed study of dose rates in the near field (within 20 meters) are presented and, for easy application, the cask centerline dose rates are fitted into empirical equations at cask centerline distances up to 2000 meters from the surface of the cask

  16. The short term effects of Low-dose-rate Radiation on EL4 Lymphoma Cell

    International Nuclear Information System (INIS)

    Bong, Jin Jong; Kang, Yu Mi; Shin, Suk Chull; Choi, Moo Hyun; Choi, Seung Jin; Kim, Hee Sun; Lee, Kyung Mi

    2012-01-01

    To determine the biological effects of low-dose-rate radiation ( 137 Cs, 2.95 mGy/h) on EL4 lymphoma cells during 24 h, we investigated the expression of genes related to apoptosis, cell cycle arrest, DNA repair, iron transport, and ribonucleotide reductase. EL4 cells were continuously exposed to low-dose-rate radiation (total dose: 70.8 mGy) for 24 h. We analyzed cell proliferation and apoptosis by trypan blue exclusion and flow cytometry, gene expression by real-time PCR, and protein levels with the apoptosis ELISA kit. Apoptosis increased in the Low-dose-rate irradiated cells, but cell number did not differ between non- (Non-IR) and Low-dose-rate irradiated (LDR-IR) cells. In concordance with apoptotic rate, the transcriptional activity of ATM, p53, p21, and Parp was upregulated in the LDR-IR cells. Similarly, Phospho-p53 (Ser15), cleaved caspase 3 (Asp175), and cleaved Parp (Asp214) expression was upregulated in the LDR-IR cells. No difference was observed in the mRNA expression of DNA repair-related genes (Msh2, Msh3, Wrn, Lig4, Neil3, ERCC8, and ERCC6) between Non-IR and LDR-IR cells. Interestingly, the mRNA of Trfc was upregulated in the LDR-IR cells. Therefore, we suggest that short-term Low-dose-rate radiation activates apoptosis in EL4 lymphoma cells.

  17. The short term effects of Low-dose-rate Radiation on EL4 Lymphoma Cell

    Energy Technology Data Exchange (ETDEWEB)

    Bong, Jin Jong; Kang, Yu Mi; Shin, Suk Chull; Choi, Moo Hyun; Choi, Seung Jin; Kim, Hee Sun [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd, Seoul (Korea, Republic of); Lee, Kyung Mi [Global Research Lab, BAERI Institute, Dept. of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul (Korea, Republic of)

    2012-06-15

    To determine the biological effects of low-dose-rate radiation ({sup 137}Cs, 2.95 mGy/h) on EL4 lymphoma cells during 24 h, we investigated the expression of genes related to apoptosis, cell cycle arrest, DNA repair, iron transport, and ribonucleotide reductase. EL4 cells were continuously exposed to low-dose-rate radiation (total dose: 70.8 mGy) for 24 h. We analyzed cell proliferation and apoptosis by trypan blue exclusion and flow cytometry, gene expression by real-time PCR, and protein levels with the apoptosis ELISA kit. Apoptosis increased in the Low-dose-rate irradiated cells, but cell number did not differ between non- (Non-IR) and Low-dose-rate irradiated (LDR-IR) cells. In concordance with apoptotic rate, the transcriptional activity of ATM, p53, p21, and Parp was upregulated in the LDR-IR cells. Similarly, Phospho-p53 (Ser15), cleaved caspase 3 (Asp175), and cleaved Parp (Asp214) expression was upregulated in the LDR-IR cells. No difference was observed in the mRNA expression of DNA repair-related genes (Msh2, Msh3, Wrn, Lig4, Neil3, ERCC8, and ERCC6) between Non-IR and LDR-IR cells. Interestingly, the mRNA of Trfc was upregulated in the LDR-IR cells. Therefore, we suggest that short-term Low-dose-rate radiation activates apoptosis in EL4 lymphoma cells.

  18. Using RADFET for the real-time measurement of gamma radiation dose rate

    Science.gov (United States)

    Andjelković, Marko S.; Ristić, Goran S.; Jakšić, Aleksandar B.

    2015-02-01

    RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0 , 10 , 20  and 30 V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65  to 32.1 Gy h-1 and up to the total absorbed dose of 25 Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose.

  19. Using RADFET for the real-time measurement of gamma radiation dose rate

    International Nuclear Information System (INIS)

    Andjelković, Marko S; Ristić, Goran S; Jakšić, Aleksandar B

    2015-01-01

    RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0 , 10 , 20  and 30 V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65  to 32.1 Gy h −1 and up to the total absorbed dose of 25 Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose. (paper)

  20. Radiation response of industrial materials: Dose-rate and morphology implications

    International Nuclear Information System (INIS)

    Berejka, Anthony J.

    2007-01-01

    Industrial uses of ionizing radiation mostly rely upon high current, high dose-rate (100 kGy/s) electron beam (EB) accelerators. To a lesser extent, industry uses low dose-rate (2.8 x 10 -3 kGy/s) radioactive Cobalt-60 as a gamma source, generally for some rather specific purposes, as medical device sterilization and the treatment of food and foodstuffs. There are nearly nine times as many (∼1400) high current EB units in commercial operation than gamma sources (∼160). However, gamma sources can be easily scaled-down so that much research on materials effects is conducted using gamma radiation. Likewise, laboratories are more likely to have very low beam current and consequently low dose-rate accelerators such as Van de Graaff generators and linear accelerators. With the advent of very high current EB accelerators, X-ray processing has become an industrially viable option. With X-rays from high power sources, dose-rates can be modulated based upon accelerator power and the attenuation of the X-ray by the distance of the material from the X-ray target. Dose and dose-rate dependence has been found to be of consequence in several commercial applications which can employ the use of ionizing radiation. The combination of dose and dose-rate dependence of the polymerization and crosslinking of wood impregnants and of fiber composite matrix materials can yield more economically viable results which have promising commercial potential. Monomer and oligomer structure also play an important role in attaining these desirable results. The influence of morphology is shown on the radiation response of olefin polymers, such as ethylene, propylene and isobutylene polymers and their copolymers. Both controlled morphology and controlled dose-rate have commercial consequences. These are also impacted both by the adroit selection of materials and through the possible use of X-ray processing

  1. Effect of radiation dose-rate on hematopoietic cell engraftment in adult zebrafish.

    Directory of Open Access Journals (Sweden)

    Tiffany J Glass

    Full Text Available Although exceptionally high radiation dose-rates are currently attaining clinical feasibility, there have been relatively few studies reporting the biological consequences of these dose-rates in hematopoietic cell transplant (HCT. In zebrafish models of HCT, preconditioning before transplant is typically achieved through radiation alone. We report the comparison of outcomes in adult zebrafish irradiated with 20 Gy at either 25 or 800 cGy/min in the context of experimental HCT. In non-transplanted irradiated fish we observed no substantial differences between dose-rate groups as assessed by fish mortality, cell death in the kidney, endogenous hematopoietic reconstitution, or gene expression levels of p53 and ddb2 (damage-specific DNA binding protein 2 in the kidney. However, following HCT, recipients conditioned with the higher dose rate showed significantly improved donor-derived engraftment at 9 days post transplant (p ≤ 0.0001, and improved engraftment persisted at 31 days post transplant. Analysis for sdf-1a expression, as well as transplant of hematopoietic cells from cxcr4b -/- zebrafish, (odysseus, cumulatively suggest that the sdf-1a/cxcr4b axis is not required of donor-derived cells for the observed dose-rate effect on engraftment. Overall, the adult zebrafish model of HCT indicates that exceptionally high radiation dose-rates can impact HCT outcome, and offers a new system for radiobiological and mechanistic interrogation of this phenomenon. Key words: Radiation dose rate, Total Marrow Irradiation (TMI, Total body irradiation (TBI, SDF-1, Zebrafish, hematopoietic cell transplant.

  2. Relationships betwen mitotic delay and the dose rate of X radiation

    International Nuclear Information System (INIS)

    Yi, P.N.; Rha, C.K.; Evans, H.H.; Beer, J.Z.

    1994-01-01

    Upon exposure of cells to radiation delivered at a continuous low dose rate, cell proliferation may be sustained with the cells exhibiting a constant doubling time that is independent of the total dose. The doubling time or mitotic delay under these conditions has been shown to depend on the dose rate in HeLa, V79 and P388F cells. Reanalysis of the data for these particular cell lines shows that there is a threshold dose rate for mitotic delay, and that above the threshold there is a linear relationship between the length of mitotic delay and the logarithm of the dose rate which is referred to as the dose-rate response. We have observed the same relationships for L5178Y (LY)-R and LY-S cells exposed to low-dose-rate radiation. The threshold dose rates for LY-R, LY-S and P388F cells are similar (0.01-0.02 Gy/h) and are much lower than for V79 and HeLa cells. The slope of the dose-rate response curve is the greatest for HeLa cells, followed in order by LY-S, V79 and P388F cells, and finally by LY-R cells. The slopes for HeLa and LY-R cells differ by a factor of 35. 20 refs., 3 figs., 1 tab

  3. Analysis of the payment rates and classification of services on radiation oncology

    International Nuclear Information System (INIS)

    Shin, K. H.; Shin, H. S.; Pyo, H. R.; Lee, K. C.; Lee, Y. T.; Myoung, H. B.; Yeom, Y. K.

    1997-01-01

    The main purpose of this study is to develop new payment rates for services of radiation oncology, considering costs of treating patients. A survey of forty hospitals has been conducted in order to analyze the costs of treating patients. Before conducting the survey, we evaluated and reclassified the individual service items currently using as payments units on the fee-for-service reimbursement system. This study embodies the analysis of replies received from the twenty four hospitals. The survey contains information about the hospitals' costs of 1995 for the reclassified service items on radiation oncology. After we adjust the hospital costs by the operating rate of medical equipment, we compare the adjusted costs with the current payment rates of individual services. The current payment rates were 5.05-6.58 times lower than the adjusted costs in treatment planning services, 2.22 times lower in block making service, 1.57-2.86 times lower in external beam irradiation services, 3.82-5.01 times lower in intracavitary and interstitial irradiation and 1.12-2.55 times lower in total body irradiation. We could conclude that the current payment system on radiation oncology does not only reflect the costs of treating patients appropriately but also classify the service items correctly. For an example, when the appropriate costs and classification are applied to TBI, the payment rates of TBI should be increased five times more than current level. (author)

  4. Dose rate effect on the yield of radiation induced response with thermal fading

    International Nuclear Information System (INIS)

    Chernov, V.; Rogalev, B.; Barboza-Flores, M.

    2005-01-01

    A model describing the dependences of the accumulation of thermally unstable radiation induced defects on the dose and dose rate is proposed. The model directly takes into account the track nature of the ionizing radiation represented as accumulation processes of defects in tracks averaged over a crystal volume considering various degrees of overlapping in space and time. The accumulation of the defects in the tracks is phenomenologically described. General expressions are obtained that allows radiation yield simulation of defects involving known creation and transformation processes. The cases considered, of linear accumulation (constant increment of the defects in tracks) and accumulation with saturation (complete saturation of the defects in one track), lead to a set of linear dose dependences with saturation, which are routinely used in luminescence and ESR dating. The accumulation, with increase of sensitivity in regions overlapped by two or more tracks, gave a set of dose dependences, from linear-sublinear-linear-saturation, distinctive of quartz up to linear-supralinear-linear-saturation. It is shown that the effect of the dose rate on dose dependences is determined by a dimensionless parameter a=Pτ/D0, where P is the dose rate, τ is the defect lifetime and D0 is the track dose. At a-bar 1 the dose rate influences basically the accumulation of thermally unstable defects. In the reverse case the dose dependences did not seems to be influenced by the dose rate

  5. Use of virtual reality to estimate radiation dose rates in nuclear plants

    International Nuclear Information System (INIS)

    Augusto, Silas C.; Mol, Antonio C.A.; Jorge, Carlos A.F.; Couto, Pedro M.

    2007-01-01

    Operators in nuclear plants receive radiation doses during several different operation procedures. A training program capable of simulating these operation scenarios will be useful in several ways, helping the planning of operational procedures so as to reduce the doses received by workers, and to minimize operations' times. It can provide safe virtual operation training, visualization of radiation dose rates, and estimation of doses received by workers. Thus, a virtual reality application, a free game engine, has been adapted to achieve the goals of this project. Simulation results for Argonauta research reactor of Instituto de Engenharia Nuclear are shown in this paper. A database of dose rate measurements, previously performed by the radiological protection service, has been used to display the dose rate distribution in the region of interest. The application enables the user to walk in the virtual scenario, displaying at all times the dose accumulated by the avatar. (author)

  6. Recent international regulations: low dose-low rate radiation protection and the demise of reason.

    Science.gov (United States)

    Okkalides, Demetrios

    2008-01-01

    The radiation protection measures suggested by the International Committee for Radiation Protection (ICRP), national regulating bodies and experts, have been becoming ever more strict despite the decrease of any information supporting the existence of the Linear no Threshold model (LNT) and of any adverse effects of Low Dose Low Rate (LDLR) irradiation. This tendency arises from the disproportionate response of human society to hazards that are currently in fashion and is unreasonable. The 1 mSv/year dose limit for the public suggested by the ICRP corresponds to a 1/18,181 detriment-adjusted cancer risk and is much lower than other hazards that are faced by modern societies such as e.g. driving and smoking which carry corresponding rate risks of 1/2,100 and 1/2,000. Even worldwide deadly work accidents rate is higher at 1/ 8,065. Such excessive safety measures against minimal risks from man made radiation sources divert resources from very real and much greater hazards. In addition they undermine research and development of radiation technology and tend to subjugate science and the quest for understanding nature to phobic practices.

  7. Dose Rate Effect on Grafting by Gamma Radiation of DMAEMA onto Flexible PVC

    International Nuclear Information System (INIS)

    Panzarini, L.C.G.A.; Araujo, F.D.C.; Martinello, V.C.; Somesari, E.; Manzoli, J.E.; Silveira, C.; Paes, H.A.; Moura, E.

    2009-01-01

    Intravenous tubing, blood bags and catheters stays in contact with blood and body fluids. They are normally made by flexible PVC. The contact of PVC with this fluid is not possible for long periods and there is the necessity of addition of non-thrombogenic substances into blood. This work shows the radiation grafting process to produce copolymer PVC-g-DMAEMA, a new material that allows a future grafting of Heparin on it, and will have the perspective of avoiding undesirable substances additions to blood or body fluid contact. In this preliminary work, only radiation dose rate effect on grafting was studied

  8. Nonlinear radiative heat flux and heat source/sink on entropy generation minimization rate

    Science.gov (United States)

    Hayat, T.; Khan, M. Waleed Ahmed; Khan, M. Ijaz; Alsaedi, A.

    2018-06-01

    Entropy generation minimization in nonlinear radiative mixed convective flow towards a variable thicked surface is addressed. Entropy generation for momentum and temperature is carried out. The source for this flow analysis is stretching velocity of sheet. Transformations are used to reduce system of partial differential equations into ordinary ones. Total entropy generation rate is determined. Series solutions for the zeroth and mth order deformation systems are computed. Domain of convergence for obtained solutions is identified. Velocity, temperature and concentration fields are plotted and interpreted. Entropy equation is studied through nonlinear mixed convection and radiative heat flux. Velocity and temperature gradients are discussed through graphs. Meaningful results are concluded in the final remarks.

  9. Dose-rate effects on mammalian cells exposed to ionizing radiation

    International Nuclear Information System (INIS)

    Mitchell, J.B.

    1978-01-01

    The effect of irradiation on the life cycle and on cell survival was studied for a range of different dose rates. Log phase, plateau phase and synchronized cultures of different mammalian cells were used. Cell cycle redistribution during the radiation exposure was found to be a very important factor in determining the overall dose-rate effect for log phase and synchronized cells. In fact, cell cycle redistribution during the exposure, in some instances, resulted in a lower dose rate being more effective in cell killing per unit dose than a higher dose rate. For plateau phase cultures, where cell cycle times are greatly lengthened, the effects of redistribution in regard to cell killing was virtually eliminated. Both fed and unfed plateau phase cultures exhibited a dose-rate effect, but it was found that below dose rates of 154 rad/h there is no further loss in effectiveness

  10. 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.)

  11. Measurement of environmental radiation exposure rates from Vernita, Hanford Reach, and Richland area shores. Addendum 1

    International Nuclear Information System (INIS)

    Cooper, A.T.

    1995-02-01

    Environmental radiation exposure rate measurements are taken on and around the Hanford Site for Pacific Northwest Laboratory's Hanford Site Surface Environmental Surveillance Project. In 1992, environmental radiation exposure rate measurements were taken from shoreline and island areas ranging from Vernita, along the Hanford Reach, down to the Richland Pumphouse. Measurements were taken primarily at locations known or expected to have elevated exposure rates as determined by examination of aerial photographs depicting radiation exposure measurements. Results from the 1992 survey indicated radiation exposure rates taken from the Hanford Reach area were elevated in comparison to the measurements taken from the Vernita area with ranges of 8 to 28 μR/hr and 4 to 11 μR/hr, respectively. In January 1994, additional shoreline radiation exposure rate measurements were taken from the Vernita, Hanford Reach, and Richland areas to determine the relationship of radiation exposure rates along the Richland area shores when compared to Vernita and Hanford Reach area exposure rates (measurements along the Richland area were not collected during the 1992 survey). This report discusses the 1994 results and is an addendum to the report that discussed the 1992 survey. An analysis of variance indicated a significant location interaction at a p-value of 0.0014. To determine differences between paried locations a post-hoc comparison of location means was performed on log transformed data using the Scheffacute e's F-test. This test indicated a significant difference between Hanford Reach and Richland area means with a mean difference of 0.075 /μR/hr and a p-value of 0.0014. No significant difference was found between Hanford Reach and Vernita area means: The mean difference was 0.031 μR/hr and the p-value was 0.3138. No significant difference was found between Vernita and Richland area means with a mean difference of 0.044 μR/hr and a p-value of 0.1155

  12. Correlation of radiation dose and heart rate in dual-source computed tomography coronary angiography

    International Nuclear Information System (INIS)

    Laspas, Fotios; Roussakis, Arkadios; Kritikos, Nikolaos; Efthimiadou, Roxani; Kehagias, Dimitrios; Andreou, John; Tsantioti, Dimitra

    2011-01-01

    Background: Computed tomography coronary angiography (CTCA) has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but the relatively high radiation dose remains a major concern. Purpose: To evaluate the relationship between radiation exposure and heart rate (HR), in dual-source CTCA. Material and Methods: Data from 218 CTCA examinations, performed with a dual-source 64-slices scanner, were statistically evaluated. Effective radiation dose, expressed in mSv, was calculated as the product of the dose-length product (DLP) times a conversion coefficient for the chest (mSv = DLPx0.017). Heart rate range and mean heart rate, expressed in beats per minute (bpm) of each individual during CTCA, were also provided by the system. Statistical analysis of effective dose and heart rate data was performed by using Pearson correlation coefficient and two-sample t-test. Results: Mean HR and effective dose were found to have a borderline positive relationship. Individuals with a mean HR >65 bpm observed to receive a statistically significant higher effective dose as compared to those with a mean HR =65 bpm. Moreover, a strong correlation between effective dose and variability of HR of more than 20 bpm was observed. Conclusion: Dual-source CT scanners are considered to have the capability to provide diagnostic examinations even with high HR and arrhythmias. However, it is desirable to keep the mean heart rate below 65 bpm and heart rate fluctuation less than 20 bpm in order to reduce the radiation exposure

  13. Terrestrial gamma radiation dose rates and radiological mapping of Terengganu state, Malaysia

    International Nuclear Information System (INIS)

    Garba, N.N.

    2015-01-01

    Measurement of terrestrial gamma radiation dose (TGRD) rates in Terengganu state, Malaysia was carried out from 145 different locations using NaI[Tl] micro roentgen survey meter. The measured TGRD rates ranged from 35 to 340 nGy h -1 with mean value of 150 nGy h -1 . The annual effective dose to population was found to be 0.92 mSv y -1 . The data obtained were used in constructing the gamma isodose map using ArcGis 9.3 which shows the distribution of TGRD rates across the state. (author)

  14. Survival and Complication Rate of Radiation Therapy in Stage I and II Carcinoma of uterine Cervix

    International Nuclear Information System (INIS)

    Ma, Sun Young; Cho, Heung Lea; Sohn, Seung Chang

    1995-01-01

    Purpose : To analyze survival rate and late rectal and bladder complication for patients with stage with stage I and II carcinoma of uterine cervix treated by radiation alone or combined with chemotherapy. Materials and Methods : Between November 1984 and December 1993, 127 patients with stage I and II carcinoma of uterine cervix treated by radiation alone or combined therapy of radiation and chemotherapy. Retrospective analysis for survival rate was carried out on eligible 107 patients and review for complication was possible in 91 patients. The median follow-up was 47 months (range 3-118) and the median age of patients was 56 years (range 31-76). 26 patients were stage IB by FIGO classification. 40 were stage IIA and 41 were stage IIB. 86 cases were treated by radiation alone and 21 were treated by radiation and chemotherapy. 101 patients were treated with intracavitary radiation therapy (ICRT), of these, 80 were received low dose rate (LDR) ICRT and 21 were received high dose rate (HDR) ICRT. Of the patients who received LDR ICRT, 63 were treated by 1 intracavitary insertion and 17 were underwent 2 insertions. And we evaluated the external radiation dose and midline shield. Results : Acturial survival rate at 5 years was 92% for stage IB, 75% for stage IIA, 53% for stage IIB and 69% in all patients. Grade 1 rectal complications were developed in 20 cases(22%), grade 2 were in 22 cases (24%), 22 cases (24%) of grade 1 urinary complications and 17 cases (19%) of grade 2 urinary complications were observed But no patients had severe complications that needed surgical management or admission care. Maximum bladder dose for the group of patients with urinary complications was higher than that for the patients without urinary complications(7608cGy v 6960cGy, p<0.01). Maximum rectal dose for the group of patients with rectal complications was higher than that for the patients without urinary complications (7041cGy v 6269cGy, p<0.01). While there was no significant

  15. Do Case Rates Affect Physicians' Clinical Practice in Radiation Oncology?: An Observational Study.

    Directory of Open Access Journals (Sweden)

    Bryan A Loy

    Full Text Available Case rate payments combined with utilization monitoring may have the potential to improve the quality of care by reducing over and under-treatment. Thus, a national managed care organization introduced case rate payments at one multi-site radiation oncology provider while maintaining only fee-for-service payments at others. This study examined whether the introduction of the payment method had an effect on radiation fractions administered when compared to clinical guidelines. The number of fractions of radiation therapy delivered to patients with bone metastases, breast, lung, prostate, and skin cancer was assessed for concordance with clinical guidelines. The proportion of guideline-based care ascertained from the payer's claims database was compared before (2011 and after (2013 the payment method introduction using relative risks (RR. After the introduction of case rates, there were no significant changes in guideline-based care in breast, lung, and skin cancer; however, patients with bone metastases and prostate cancer were significantly more likely to have received guideline-based care (RR = 2.0 and 1.1, respectively, p<0.05. For the aggregate of all cancers, the under-treatment rate significantly declined (p = 0.008 from 4% to 0% after the introduction of case rate payments, while the over-treatment rate remained steady at 9%, with no significant change (p = 0.20. These findings suggest that the introduction of case rate payments did not adversely affect the rate of guideline-based care at the provider examined. Additional research is needed to isolate the effect of the payment model and assess implications in other populations.

  16. Do Case Rates Affect Physicians' Clinical Practice in Radiation Oncology?: An Observational Study.

    Science.gov (United States)

    Loy, Bryan A; Shkedy, Clive I; Powell, Adam C; Happe, Laura E; Royalty, Julie A; Miao, Michael T; Smith, Gary L; Long, James W; Gupta, Amit K

    2016-01-01

    Case rate payments combined with utilization monitoring may have the potential to improve the quality of care by reducing over and under-treatment. Thus, a national managed care organization introduced case rate payments at one multi-site radiation oncology provider while maintaining only fee-for-service payments at others. This study examined whether the introduction of the payment method had an effect on radiation fractions administered when compared to clinical guidelines. The number of fractions of radiation therapy delivered to patients with bone metastases, breast, lung, prostate, and skin cancer was assessed for concordance with clinical guidelines. The proportion of guideline-based care ascertained from the payer's claims database was compared before (2011) and after (2013) the payment method introduction using relative risks (RR). After the introduction of case rates, there were no significant changes in guideline-based care in breast, lung, and skin cancer; however, patients with bone metastases and prostate cancer were significantly more likely to have received guideline-based care (RR = 2.0 and 1.1, respectively, p<0.05). For the aggregate of all cancers, the under-treatment rate significantly declined (p = 0.008) from 4% to 0% after the introduction of case rate payments, while the over-treatment rate remained steady at 9%, with no significant change (p = 0.20). These findings suggest that the introduction of case rate payments did not adversely affect the rate of guideline-based care at the provider examined. Additional research is needed to isolate the effect of the payment model and assess implications in other populations.

  17. Effect of different ionizing radiation dose rates on the Staphylococcal enterotoxin in mechanically deboned chicken meat

    International Nuclear Information System (INIS)

    Azevedo, Heliana de; Brito, Poliana de Paula; Fukuma, Henrique Takuji; Roque, Claudio Vitor; Custodio, Wilson; Kodama, Yasko; Miya, Norma Terugo Nago; Pereira, Jose Luiz

    2009-01-01

    Samples weighing 50g each were prepared from allotments of back with skin MDCM, to the EEB contamination or not (control). Each sample of MDCM contaminated or not with EEB was conditioned in low density polyethylene bag, frozen (-18 ± 1 deg C) for one night in a tunnel and irradiated with gamma rays from 60 Co source in this state with doses of 0.0 kGy (control), 1.5 kGy (5.7 kGy.h -1 - higher dose rate, 1.8 kGy.h -1 - intermediary dose rate and 0.6 kGy.h -1 - lower dose rate) and 3.0 kGy (8.4 kGy.h - '1 - higher dose rate, 2.4 kGy.h -1 - intermediary dose rate and 0.6 kGy.h -1 - lower dose rate). Irradiated or non irradiated MDCM samples were processed to the EEB extraction, according to the VIDAS Staph enterotoxin II kit (bioMerieux) manufacturer protocol. The calculation to determinate the MDCM EEB recovery after the sample (control or irradiated) processing were carried out applying the principle of mass balance, along the whole process. Described experiment was performed in triplicate. Results showed that the irradiation process was effective to remove the MDCM EEB, to both 1.5 kGy and 3.0 kGy. According to the expected, doses of 3.0 kGy showed the highest values of MDCM EEB removal. Regarding the effect of dose rate of radiation on the removal of EEB of the MDCM, it could be observed only for samples irradiated with 1.5 kGy radiation dose; in these processing conditions, the highest value of EEB removal was obtained for samples processed with low radiation dose rate. (author)

  18. Balance of longwave radiation employing the rate of solar radiation for Santa Maria, Rio Grande do Sul, Brazil1

    Directory of Open Access Journals (Sweden)

    Evandro Zanini Righi

    Full Text Available New coefficients were determined for the weighting term for cloudiness in the Brunt-Penman equation using the rate of solar radiation (RK in place of the rate of sunshine duration (n/N. The coefficients in the Brutsaert method proposed for daytime in southern Brazil were also tested and adjusted, and the method was selected which gave the more accurate daily results in relation to the original Brunt-Penman equation, for Santa Maria in the state of Rio Grande do Sul, Brazil (RS. Meteorological data covering 2,472 days obtained from the automatic and conventional weather stations in Santa Maria were used. The coefficients were adjusted by linear and nonlinear regression methods depending on the model, using 2/3 of the data. The adjusted equations were tested with the remaining 1/3 of the data. The Brunt-Penman equation modified by the term for cloudiness weighted both for solar radiation incident on the surface with no cloudiness (RK,R and for solar radiation incident at the top of the atmosphere (RK,K, were those that resulted in the best statistical indices relative to the original Brunt-Penman equation. In those equations the boundary conditions, 0.3 ≥ RK,R ≥ 1 or RK,K ≤ 0.22, were imposed. Although having similar statistical indices, a sensitivity analysis showed that the Brutsaert equation and other weightings for cloudiness resulted in larger deviations when compared to the original Brunt-Penman equation, in addition to having greater complexity for practical application.

  19. Stadium IB - IIA cervical cancer patient’s survival rate after receiving definitive radiation and radical operation therapy followed by adjuvant radiation therapy along with analysis of factors affecting the patient’s survival rate

    Science.gov (United States)

    Ruslim, S. K.; Purwoto, G.; Widyahening, I. S.; Ramli, I.

    2017-08-01

    To evaluate the characteristics and overall survival rates of early stage cervical cancer (FIGO IB-IIA) patients who receive definitive radiation therapy and those who are prescribed adjuvant postoperative radiation and to conduct a factors analysis of the variables that affect the overall survival rates in both groups of therapy. The medical records of 85 patients with cervical cancer FIGO stages IB-IIA who were treated at the Department of Radiotherapy of Cipto Mangunkusumo Hospital were reviewed and analyzed to determine their overall survival and the factors that affected it between a definitive radiation group and an adjuvant postoperative radiation group. There were 25 patients in the definitive radiation and 60 patients in the adjuvant radiation group. The overall survival rates in the adjuvant radiation group at years one, two, and three were 96.7%, 95%, and 93.3%, respectively. Negative lymph node metastasis had an average association with overall survival (p 12 g/dl was a factor with an average association with the overall survival (p cervical cancer FIGO stage IB-IIA patients who received definitive radiation or adjuvant postoperative radiation. Negative lymph node metastasis had an effect on the overall survival rate in the adjuvant postoperative radiation group, while a preradiation Hb level >12 g/dl tended to affect the overall survival in the definitive radiation group patients.

  20. Radiation-chemical discussion on inverse dose-rate effect observed in radiation-induced strand breaks of plasmid DNA

    International Nuclear Information System (INIS)

    Masuda, Takahiro

    1994-01-01

    Experimental results of inverse dose-rate effect, so-called Kada Effects, which was published by Takakura and her coworkers on radiation-induced strand breaks of plasmid DNA in aerated aqueous solution, have been kinetically analyzed and discussed on the basis of radiation chemistry. the kinetic analysis indicates that there are two possible mechanisms; 1) equilibrium mixture of O 2 - and HO 2 is responsible for strand breaks of DNA, and 2) peroxyl radical produced from citrate is effective for the strand breaks. However, the detailed kinetic analysis revealed that the latter is improbable because unimolecular decay of the peroxyl radical must be assumed to be negligible for its participation despite fast decay of analogous organic peroxyl radicals. The analysis has also given 9.93±0.10 dm 3 mol -1 s -1 per nucleotide unit, which corresponds to 7.62 x 10 4 dm 3 mol -1 s -1 per DNA molecule, as the rate constant for the reaction of the equilibrium mixture with plasmid pBR 322 DNA. Furthermore the probability that the reaction of the mixture with a nucleotide unit of DNA leads to strand breaks was obtained to be 3.36 x 10 -3 for gamma-irradiated system and 1.98 x 10 -3 for beta-irradiated system, respectively. (author)

  1. A review of advances in pixel detectors for experiments with high rate and radiation

    Science.gov (United States)

    Garcia-Sciveres, Maurice; Wermes, Norbert

    2018-06-01

    The large Hadron collider (LHC) experiments ATLAS and CMS have established hybrid pixel detectors as the instrument of choice for particle tracking and vertexing in high rate and radiation environments, as they operate close to the LHC interaction points. With the high luminosity-LHC upgrade now in sight, for which the tracking detectors will be completely replaced, new generations of pixel detectors are being devised. They have to address enormous challenges in terms of data throughput and radiation levels, ionizing and non-ionizing, that harm the sensing and readout parts of pixel detectors alike. Advances in microelectronics and microprocessing technologies now enable large scale detector designs with unprecedented performance in measurement precision (space and time), radiation hard sensors and readout chips, hybridization techniques, lightweight supports, and fully monolithic approaches to meet these challenges. This paper reviews the world-wide effort on these developments.

  2. Predicted Rates of Secondary Malignancies From Proton Versus Photon Radiation Therapy for Stage I Seminoma

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Charles B., E-mail: csimone@alumni.upenn.edu [Department of Radiation Oncology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania (United States); Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Kramer, Kevin [Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland (United States); O' Meara, William P. [Division of Radiation Oncology, National Naval Medical Center, Bethesda, Maryland (United States); Bekelman, Justin E. [Department of Radiation Oncology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania (United States); Belard, Arnaud [Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland (United States); McDonough, James [Department of Radiation Oncology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania (United States); O' Connell, John [Radiation Oncology Service, Walter Reed Army Medical Center, Washington, DC (United States)

    2012-01-01

    Purpose: Photon radiotherapy has been the standard adjuvant treatment for stage I seminoma. Single-dose carboplatin therapy and observation have emerged as alternative options due to concerns for acute toxicities and secondary malignancies from radiation. In this institutional review board-approved study, we compared photon and proton radiotherapy for stage I seminoma and the predicted rates of excess secondary malignancies for both treatment modalities. Methods and Material: Computed tomography images from 10 consecutive patients with stage I seminoma were used to quantify dosimetric differences between photon and proton therapies. Structures reported to be at increased risk for secondary malignancies and in-field critical structures were contoured. Reported models of organ-specific radiation-induced cancer incidence rates based on organ equivalent dose were used to determine the excess absolute risk of secondary malignancies. Calculated values were compared with tumor registry reports of excess secondary malignancies among testicular cancer survivors. Results: Photon and proton plans provided comparable target volume coverage. Proton plans delivered significantly lower mean doses to all examined normal tissues, except for the kidneys. The greatest absolute reduction in mean dose was observed for the stomach (119 cGy for proton plans vs. 768 cGy for photon plans; p < 0.0001). Significantly more excess secondary cancers per 10,000 patients/year were predicted for photon radiation than for proton radiation to the stomach (4.11; 95% confidence interval [CI], 3.22-5.01), large bowel (0.81; 95% CI, 0.39-1.01), and bladder (0.03; 95% CI, 0.01-0.58), while no difference was demonstrated for radiation to the pancreas (0.02; 95% CI, -0.01-0.06). Conclusions: For patients with stage I seminoma, proton radiation therapy reduced the predicted secondary cancer risk compared with photon therapy. We predict a reduction of one additional secondary cancer for every 50 patients

  3. Estimation of daily flow rate of photovoltaic water pumping systems using solar radiation data

    Science.gov (United States)

    Benghanem, M.; Daffallah, K. O.; Almohammedi, A.

    2018-03-01

    This paper presents a simple model which allows us to contribute in the studies of photovoltaic (PV) water pumping systems sizing. The nonlinear relation between water flow rate and solar power has been obtained experimentally in a first step and then used for performance prediction. The model proposed enables us to simulate the water flow rate using solar radiation data for different heads (50 m, 60 m, 70 m and 80 m) and for 8S × 3P PV array configuration. The experimental data are obtained with our pumping test facility located at Madinah site (Saudi Arabia). The performances are calculated using the measured solar radiation data of different locations in Saudi Arabia. Knowing the solar radiation data, we have estimated with a good precision the water flow rate Q in five locations (Al-Jouf, Solar Village, AL-Ahsa, Madinah and Gizan) in Saudi Arabia. The flow rate Q increases with the increase of pump power for different heads following the nonlinear model proposed.

  4. Radiation-induced cell mutations as a function of dose rate

    International Nuclear Information System (INIS)

    Kiefer, J.

    1987-01-01

    A brief review of the data in the literature is presented and forms the background of the experimental data given by the author obtained with exponential long-term cultures of V79 hamster cells exposed over a period of up to 35 days to different dose rates of gamma radiation. The experimental results show that at a dose rate of 40 mGy/hour the number of induced mutations is reduced, - which is in agreement with literature data - , but a dose rate of less than 30 mGy/hour makes the induced mutations leap to a value clearly higher than those induced by acute irradiation. As in addition to the mutations recombination is a significant factor of the radiation risk, experiments with a heterozygotic yeast strain have been made, as there is to date no reliable mammalian cell system available for this kind of research. Long-term radiation exposure of the yeast cells over a period of six weeks drastically increased the rate of recombinations, to a value higher by a factor of about 4 than that induced by acute irradiation. (orig.) [de

  5. Radiation-induced attenuation in polarization maintaining fibers: low dose rate response, stress, and materials effects

    International Nuclear Information System (INIS)

    Gingerich, M.E.; Friebele, E.J.; Hickey, S.J.; Brambani, L.A.; Onstott, J.R.

    1989-01-01

    The loss induced in polarization-maintaining (PM) fibers by low dose rate <0.01 Gy/h, where 1 Gy = 100 rads(Si) radiation exposure has been found to vary from <0.4 to ∼6 dB/km-10 Gy, depending on the wavelength of measurement and the fiber. Correlations have been established between low dose rate response and the ''permanent'' induced loss determined by fitting the recovery of the induced loss following high dose rate exposure to nth-order kinetics. Using this technique, both 0.85- and 1.3-μm PM fibers have been found which show virtually no permanent incremental loss and would therefore appear to be resistant to low dose rate radiation environments. The asymmetric stress inherent in PM fibers has been shown to reduce the permanent induced loss, while the recovery of the radiation-induced attenuation was found to be enhanced in fibers with Ge-F-doped silica clads

  6. Advanced gastric adenocarcinoma. Influence of preoperative radiation therapy on toxicity and long-term survival rates

    International Nuclear Information System (INIS)

    Malzoni, Carlos Eduardo

    1996-01-01

    The surgical treatment of gastric cancer has better long-term survival rates when performed in patients with early gastric cancer. Worse results are obtained in treatment of advanced gastric cancer. Most patients in west centers are treated in advanced stages. A great number of them go through a surgical treatment unable by itself to cure them. the frequent local recurrence caused by failure of the surgical treatment has been keeping poor survival rates in patients with advanced gastric cancer for decades. The desire of improving survival is the reason of the use of adjuvant therapies. This paper achieved the retrospective study of the influence of preoperative radiation therapy (2000 cGy) in long-term survival rates (120 months) of patients with advanced gastric cancer on stages IIIa, IIIb and IV. The possible injuries caused in the liver and kidney were observed also as well as first group was treated by surgical and radiation therapies and the second received surgical treatment only. There was no statistical difference between the two groups when sex, age, race, occurrence of other diseases, nutritional assessment, TNM stage, occurrence of obstruction or bleeding caused by tumor, surgical procedure and hepatic and renal function were considered. Survival rates and changes on hepatic and renal function were statistically compared. The results showed a statistic improvement on the long-term survival rates of stage IIIa patients treated by preoperative radiation therapy. No statistic difference was observed on hepatic or renal function between the groups. No adverse influence of radiation therapy method was detected by the used parameters. There was no statistical difference between the two groups when immediate surgical complications were considered. (author)

  7. Study on ionizing radiation to the workers' lymphocyte micronucleus rate and chromosome aberrations

    International Nuclear Information System (INIS)

    Li Jianhua; Wang Linchao; He Wei

    2007-01-01

    Objective: To study lymphocyte genetic material of an iron and steel enterprise workers exposed to the ionizing radiation, find out measures to protect their health and reduce ionizing radiation occupation harm. Methods: 342 workers were choseh as the exposed group who worked in an iron and steel enterprise in the beam installment operation, to examine their circumference blood lymphocyte micronucleus rate and the chromosome aberrations, simultaneously select 280 chefs as the control group, The irradiation dosage was determined and statistical analysis was carded out wich the consideration of their length of work and differences in work post. Results: Exposed group: the micronucleus rate masculine gender (MNR), 4 people, the masculine gender pick out rate is 12.87%. The chromosome aberration factor masculine gender (CAF), 12 people, the masculine rate is 3.51%. Control group: MNR 3 people, the asculine gender pick out rate is 1.07%; CAF 2 people, masculine gender rate is 0.72%. Comparing the two groups, every item has the significant difference. Workers in is the exposed group workers have the average exposure dose of 6.73mSv/a, MNR,CAF are illuminated to the dosage have a positive line correlation. They become increased as the job lenght prolongs. The nucleon name, the material calculation and the medical X-radial are responsible for the highest ratio. Conclusion: In iron and steel enterprises, long-time ionizing radiation can cause the workers' circumference blood lymphocyte micronucleus rate and the chromosome aberrations obvious to rise. The beam protection measures strengthened so as to reduce the harms to workers. (authors)

  8. Dose rate and fractionation: Relative importance in radiation for bone marrow transplantation

    International Nuclear Information System (INIS)

    Tarbell, N.J.; Rosenblatt, M.; Mauch, P.; Hellman, S.

    1987-01-01

    The optimal dose rate and fractionation schedules for total body irradiation (TBI) in bone marrow transplantation (BMT) are presently unknown. This study compares several fractionation and dose rate schedules that are currently in clinical use. C/sub 3/H/HeJ were given TBI and the bone marrow survival fraction was calculated using the CFU's assay. Irradiation was given as low dose rate (LDR) at 5 cGy/min or high dose rate (HDR) at 80 cGy/min, in single fraction (SF) and fractionated (FX) regimens. These results indicate no increase in survival for the normal bone marrow stem cells with fractionation either at high or low dose-rates. In fact, fractionation seemed to decrease the bone marrow survival over single fraction radiation

  9. Effects of Intraluminal Irradiation with Holmium-166 for TIPS Stenosis: Experimental Study in a Swine Model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Seon; Oh, Joo Hyeong; Kim, Deog Yoon; Park, Yong Koo; Kim, Soo Joong [Kyung Hee University Medical Center, Seoul (Korea, Republic of); Park, Sang Joon [Kang Dong Sacred Heart Hospital, Hallym University, Seoul (Korea, Republic of)

    2007-04-15

    We wanted to evaluate the effectiveness of intraluminal irradiation with Holmium-166 ({sup 166}Ho) for reducing the pseudointimal hyperplasia (PIH) in the transjugular intrahepatic portosystemic shunt (TIPS) tract in a swine model. TIPS was performed in 12 domestic pigs, after the creation of portal hypertension by intraportal injection of a mixture of N-butyl-2- cyanoacrylate (NBCA) and lipiodol. Five pigs first underwent intraluminal irradiation (30 Gy) in the parenchymal tract with using a {sup 166}Ho solution-filled balloon catheter, and this was followed by the placement of a nitinol stent in the TIPS tract. For the seven control pigs, the balloon was filled with saline and contrast media mixture. Two weeks later, follow-up portography and histological analysis were performed. TIPS was successfully performed in all twelve pigs with achieving artificially induced portal hypertension. Portography performed two weeks after TIPS showed the patent tracts in the TIPS tracts that were irradiated with {sup 166}Ho (5/5, 100%), whereas either completely (5/6, 83.3%) or partially (1/6, 16.7%) occluded TIPS were seen in the seven pigs of the nonirradiated control group, except in one pig that experienced periprocedural death due to bleeding. Histological analysis showed a statistically significant difference for the maximal PIH (irradiated: 32.8%, nonirradiated: 76.0%, p < 0.001) between the two groups. Intraluminal irradiation with 30 Gy of {sup 166}Ho for TIPS significantly improved the TIPS patency in a swine model of portal hypertension during a 2- week period of follow-up.

  10. Dose-rate dependent stochastic effects in radiation cell-survival models

    International Nuclear Information System (INIS)

    Sachs, R.K.; Hlatky, L.R.

    1990-01-01

    When cells are subjected to ionizing radiation the specific energy rate (microscopic analog of dose-rate) varies from cell to cell. Within one cell, this rate fluctuates during the course of time; a crossing of a sensitive cellular site by a high energy charged particle produces many ionizations almost simultaneously, but during the interval between events no ionizations occur. In any cell-survival model one can incorporate the effect of such fluctuations without changing the basic biological assumptions. Using stochastic differential equations and Monte Carlo methods to take into account stochastic effects we calculated the dose-survival rfelationships in a number of current cell survival models. Some of the models assume quadratic misrepair; others assume saturable repair enzyme systems. It was found that a significant effect of random fluctuations is to decrease the theoretically predicted amount of dose-rate sparing. In the limit of low dose-rates neglecting the stochastic nature of specific energy rates often leads to qualitatively misleading results by overestimating the surviving fraction drastically. In the opposite limit of acute irradiation, analyzing the fluctuations in rates merely amounts to analyzing fluctuations in total specific energy via the usual microdosimetric specific energy distribution function, and neglecting fluctuations usually underestimates the surviving fraction. The Monte Carlo methods interpolate systematically between the low dose-rate and high dose-rate limits. As in other approaches, the slope of the survival curve at low dose-rates is virtually independent of dose and equals the initial slope of the survival curve for acute radiation. (orig.)

  11. The influence of geology on terrestrial gamma radiation dose rate in Pahang state, Malaysia

    International Nuclear Information System (INIS)

    Gabdo, H.T.; Ramli, A.T.; Sanusi, M.S.; Garba, N.N.; Saleh, M.A.

    2015-01-01

    Terrestrial gamma radiation dose (TGRD) rate measurements have been made in Pahang state, Malaysia. Significant variations were found between TGRD measurements and the underlying geological formations. In some cases revealing significant elevations of TGRD. The acid-intrusive geological formation has the highest mean TGRD measurement of 367 nGy/h -1 . This is more than six times the world average value of 59 nGy/h -1 , while the quaternary geological formation has the lowest mean gamma radiation dose rate of 99 nGy h -1 . The annual effective dose equivalent outdoor to the population was 0.216 mSv. The lifetime equivalent dose and relative lifetime cancer risks for an individual living in Pahang state were 81 mSv and 4.7 x 10 -3 respectively. These values are more than two times the world average of 34 mSv and 1.95 x 10 -3 respectively. (author)

  12. Measures of association of some air pollutants. Natural ionizing radiation and cigarette smoking with mortality rates

    Energy Technology Data Exchange (ETDEWEB)

    Schwing, R C; McDonald, G C

    1976-03-01

    Two methods are employed to estimate the association of hydrocarbons, sulfur compounds, nitrogen compounds, natural ionizing radiation, and cigarette smoking with some age stratified and disease specific United States mortality rates for white males. The first method is based on a ridge regression technique and the second on a sign constrained least squares analysis. It is concluded that increased concentration of sulfur compounds and increased consumption of cigarettes are associated with increases in the total white male mortality rate. Associations for nitrogen compounds, the hydrogen index, and ionizing radiation are dependent on methodology and data stratification. The estimated elasticities are not directly comparable to those from other studies. Most estimates are fairly close except for the associations of heart disease with sulfur compounds. (JTE)

  13. Intraluminal Palmaz stent implantation. First clinical case report on a balloon-expandable vessel prosthesis

    Energy Technology Data Exchange (ETDEWEB)

    Palmaz, J C; Richter, G M; Noeldge, G; Kauffmann, G W; Wenz, W

    1987-12-01

    A 74-year-old patient suffering from severe iliac artery stenosis and claudication was chosen to be the first candidate in the world to receive the Palmaz stent, a balloon-expandable intraluminal stent. This procedure was done in the Department of Radiology, University of Freiburg, FRG. The intervention and postprocedural course were uneventful. His walking distance improved from less than 100 m to unlimited walking capacity. The intra-arterial pressure gradient and ankle-arm pressure ratio also returned to normal.

  14. Adaptive response to ionizing radiation in normal human skin fibroblasts. Enhancement of DNA repair rate and modulation of gene expression

    International Nuclear Information System (INIS)

    Toledo, S.M. de; Mitchel, R.E.J.; Azzam, E.; Ottawa Univ., ON; Raaphorst, G.P.

    1994-01-01

    Low doses and dose rates of ionizing radiation enhance the rate of DNA repair in human fibroblasts and protect the cells against radiation-induced micronucleus formation. Chronic exposures reduce the mRNA levels of the genes topoisomerase II and FACC-1 (Fanconi's anemia, group C). (authors). 11 refs., 1 tab., 2 figs

  15. Portable meter study of ionizing radiation Teletector in high rates of air kerma

    International Nuclear Information System (INIS)

    Damatto, Willian Behling; Potiens, Maria da Penha A.; Vivolo, Vitor

    2015-01-01

    A set of portable meters of ionizing radiation high rates of air kerma (teletectors) commonly used in emergencies in Brazil and sent to the Calibration Laboratory of IPEN were under several tests and analyst is parameters for the detectors behavior were established. Applied tests were: energy dependence and primarily overload with the new irradiation system. Thus it was possible to determine the most common characteristic found in these equipment (quality control programs) and new calibration criteria were established following international recommendations. (author)

  16. Single interval longwave radiation scheme based on the net exchanged rate decomposition with bracketing

    Czech Academy of Sciences Publication Activity Database

    Geleyn, J.- F.; Mašek, Jan; Brožková, Radmila; Kuma, P.; Degrauwe, D.; Hello, G.; Pristov, N.

    2017-01-01

    Roč. 143, č. 704 (2017), s. 1313-1335 ISSN 0035-9009 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : numerical weather prediction * climate models * clouds * parameterization * atmospheres * formulation * absorption * scattering * accurate * database * longwave radiative transfer * broadband approach * idealized optical paths * net exchanged rate decomposition * bracketing * selective intermittency Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 3.444, year: 2016

  17. Emesis as a Screening Diagnostic for Low Dose Rate (LDR) Total Body Radiation Exposure.

    Science.gov (United States)

    Camarata, Andrew S; Switchenko, Jeffrey M; Demidenko, Eugene; Flood, Ann B; Swartz, Harold M; Ali, Arif N

    2016-04-01

    Current radiation disaster manuals list the time-to-emesis (TE) as the key triage indicator of radiation dose. The data used to support TE recommendations were derived primarily from nearly instantaneous, high dose-rate exposures as part of variable condition accident databases. To date, there has not been a systematic differentiation between triage dose estimates associated with high and low dose rate (LDR) exposures, even though it is likely that after a nuclear detonation or radiologic disaster, many surviving casualties would have received a significant portion of their total exposure from fallout (LDR exposure) rather than from the initial nuclear detonation or criticality event (high dose rate exposure). This commentary discusses the issues surrounding the use of emesis as a screening diagnostic for radiation dose after LDR exposure. As part of this discussion, previously published clinical data on emesis after LDR total body irradiation (TBI) is statistically re-analyzed as an illustration of the complexity of the issue and confounding factors. This previously published data includes 107 patients who underwent TBI up to 10.5 Gy in a single fraction delivered over several hours at 0.02 to 0.04 Gy min. Estimates based on these data for the sensitivity of emesis as a screening diagnostic for the low dose rate radiation exposure range from 57.1% to 76.6%, and the estimates for specificity range from 87.5% to 99.4%. Though the original data contain multiple confounding factors, the evidence regarding sensitivity suggests that emesis appears to be quite poor as a medical screening diagnostic for LDR exposures.

  18. Chloroquine Improves Survival and Hematopoietic Recovery After Lethal Low-Dose-Rate Radiation

    International Nuclear Information System (INIS)

    Lim Yiting; Hedayati, Mohammad; Merchant, Akil A.; Zhang Yonggang; Yu, Hsiang-Hsuan M.; Kastan, Michael B.; Matsui, William; DeWeese, Theodore L.

    2012-01-01

    Purpose: We have previously shown that the antimalarial agent chloroquine can abrogate the lethal cellular effects of low-dose-rate (LDR) radiation in vitro, most likely by activating the ataxia-telangiectasia mutated (ATM) protein. Here, we demonstrate that chloroquine treatment also protects against lethal doses of LDR radiation in vivo. Methods and Materials: C57BL/6 mice were irradiated with a total of 12.8 Gy delivered at 9.4 cGy/hour. ATM null mice from the same background were used to determine the influence of ATM. Chloroquine was administered by two intraperitoneal injections of 59.4 μg per 17 g of body weight, 24 hours and 4 hours before irradiation. Bone marrow cells isolated from tibia, fibula, and vertebral bones were transplanted into lethally irradiated CD45 congenic recipient mice by retroorbital injection. Chimerism was assessed by flow cytometry. In vitro methylcellulose colony-forming assay of whole bone marrow cells and fluorescence activated cell sorting analysis of lineage depleted cells were used to assess the effect of chloroquine on progenitor cells. Results: Mice pretreated with chloroquine before radiation exhibited a significantly higher survival rate than did mice treated with radiation alone (80% vs. 31%, p = 0.0026). Chloroquine administration before radiation did not affect the survival of ATM null mice (p = 0.86). Chloroquine also had a significant effect on the early engraftment of bone marrow cells from the irradiated donor mice 6 weeks after transplantation (4.2% vs. 0.4%, p = 0.015). Conclusion: Chloroquine administration before radiation had a significant effect on the survival of normal but not ATM null mice, strongly suggesting that the in vivo effect, like the in vitro effect, is also ATM dependent. Chloroquine improved the early engraftment of bone marrow cells from LDR-irradiated mice, presumably by protecting the progenitor cells from radiation injury. Chloroquine thus could serve as a very useful drug for protection

  19. Impact of nitrogen rates on growth, yield and radiation use efficiency of maize under varying environments

    International Nuclear Information System (INIS)

    Khaliq, T.; Ahmad, A.; Hussain, A.

    2008-01-01

    Growth, yield and radiation use efficiency (RUE) of hybrid maize, in response to different nitrogen rates (150, 200, 250, 300, 350 kg ha/sub -1/ were analyzed for three different locations (Faisalabad, Sargodha and Sahiwal) in Punjab, Pakistan during 2004 and 2005. The results depicted a large yearly variations mainly attributed to more rainfall and incidence of solar radiation in 2005. Maize hybrids respond differently for all variable under study, at all sites except IPAR and radiation use efficiency 919 at different locations. Similar types of differences were noted in GGR and Final TOM. Increasing nitrogen rates had significant effects on CGR, final TOM and grain yield and RUE. The intercepted PAR, RUE/sub TDM/ and RUE/sub Gy/ were significantly affected by hybrid potential and nitrogen application rates. On an average RUE/sub TDM/ varied from 2.45 to 2.73 g MJ/sup -1/ at different locations, while RUE/sub Gy/ was recorded 1.12, 1.14 and 1.03 for Faisalabad, Sargodha and Sahiwal, respectively. Total dry matter and grain yield of different treatments was linearly related to IPAR at all location and the common regression (R/sup 2/) accounted for 94, 68, and 80 % for TDM and 64, 34, and 95% for grain yield at the Faisalabad, Sargodha and sahiwal, respectively. It was concluded that planting of hybrid Bemasal-202 with 300 kg N ha/sup -1/ is the best recommendation for semi-arid areas of Pakistan. (author)

  20. Do Case Rates Affect Physicians' Clinical Practice in Radiation Oncology?: An Observational Study

    Science.gov (United States)

    Loy, Bryan A.; Shkedy, Clive I.; Powell, Adam C.; Happe, Laura E.; Royalty, Julie A.; Miao, Michael T.; Smith, Gary L.; Long, James W.; Gupta, Amit K.

    2016-01-01

    Case rate payments combined with utilization monitoring may have the potential to improve the quality of care by reducing over and under-treatment. Thus, a national managed care organization introduced case rate payments at one multi-site radiation oncology provider while maintaining only fee-for-service payments at others. This study examined whether the introduction of the payment method had an effect on radiation fractions administered when compared to clinical guidelines. The number of fractions of radiation therapy delivered to patients with bone metastases, breast, lung, prostate, and skin cancer was assessed for concordance with clinical guidelines. The proportion of guideline-based care ascertained from the payer's claims database was compared before (2011) and after (2013) the payment method introduction using relative risks (RR). After the introduction of case rates, there were no significant changes in guideline-based care in breast, lung, and skin cancer; however, patients with bone metastases and prostate cancer were significantly more likely to have received guideline-based care (RR = 2.0 and 1.1, respectively, ppayment model and assess implications in other populations. PMID:26870963

  1. High-rate anisotropic ablation and deposition of polytetrafluoroethylene using synchrotron radiation process

    International Nuclear Information System (INIS)

    Inayoshi, Muneto; Ikeda, Masanobu; Hori, Masaru; Goto, Toshio; Hiramatsu, Mineo; Hiraya, Atsunari.

    1995-01-01

    Both anisotropic ablation and thin film formation of polytetrafluoroethylene (PTFE) were successfully demonstrated using synchrotron radiation (SR) irradiation of PTFE, that is, the SR ablation process. Anisotropic ablation by the SR irradiation was performed at an extremely high rate of 3500 μm/min at a PTFE target temperature of 200degC. Moreover, a PTFE thin film was formed at a high rate of 2.6 μm/min using SR ablation of PTFE. The chemical structure of the deposited film was similar to that of the PTFE target as determined from Fourier transform infrared absorption spectroscopy (FT-IR) analysis. (author)

  2. Serial measurement of radiation leakage dose rates in safekeeping at the Gammaknife room

    International Nuclear Information System (INIS)

    Baba, Sadaaki; Nozaki, Kenichi; Toyoda, Tatsuya; Wakamatsu, Osamu; Machida, Toru

    2006-01-01

    We report the serial measurement of leakage dose rates in safekeeping at the Gammaknife room during the past 4 years and 9 months by scintillation survey meter. The leakage dose rates at the radiation boundaries were the same as the natural background levels. Leakage dose rates at each shield calculation point from two 90 Sr calibration sources contained in the storehouse were negligible compared with those from 60 Co sources of the Gammaknife. 60 Co sources of the Gammaknife are arranged in 201 pieces at 10 degree interval on the circumference and in five lines within an arc of 35 degrees. Its shield container is made of iron at least 43 cm thick. We got leakage dose rates less than 40% of the calculated values. We think it is caused by the difference of each actual distance and shield thickness because 60 Co sources are usually considered as a point source in the shield calculation. There are shutters opening up and down when patients go in and out to the direction of the couch. The leakage values to this direction were about twice as much as the calculated value. So, we knew the thickness of those shutters was thinner than 43 cm. The half life time of 60 Co source calculated from the serial measurements of leakage dose rates was 4.93 years on average. It is 94% of the physical half life value of 5.27 years. We judged it was acceptable considering the difficulty of measuring low dose rate level with the radiation survey meter. Very strong correlation was observed between the decrease of 60 Co dose rate acquired from one minute measurement at the center of 18 cm diameter polysterene phantom gotten from December 2000 to August 2005 and that of computation based on the physical half life time. Likewise there was strong and more correlation with leakage dose rate in the Gammaknife room. From this, we deduce the leakage dose rate decreases according to the theory of the disintegration of radioactivity with passage of time. Revised radiation related laws took effect

  3. High rate of severe radiation dermatitis during radiation therapy with concurrent cetuximab in head and neck cancer : Results of a survey in EORTC institutes

    NARCIS (Netherlands)

    Giro, Christian; Berger, Bernhard; Boelke, Edwin; Ciernik, I. Frank; Duprez, Frederic; Locati, Laura; Maillard, Sophie; Ozsahin, Mahmut; Pfeffer, Raphael; Robertson, A. Gerry; Langendijk, Johannes A.; Budach, Wilfried

    Objective: Examination of the rate of grade III or grade IV radiation dermatitis during treatment of head and neck cancer (HNC) with radiotherapy (RT) and concurrent cetuximab in EORTC centres. Materials and method: A questionnaire was sent to all members of the EORTC Radiation Oncology Group and

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

    Science.gov (United States)

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

    2017-12-01

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

  5. Fallopian tube intraluminal tumor spread from noninvasive precursor lesions: a novel metastatic route in early pelvic carcinogenesis.

    Science.gov (United States)

    Bijron, Jonathan G; Seldenrijk, Cornelis A; Zweemer, Ronald P; Lange, Joost G; Verheijen, René H M; van Diest, Paul J

    2013-08-01

    Pelvic serous carcinoma is usually advanced stage at diagnosis, indicating that abdominal spread occurs early in carcinogenesis. Recent discovery of a precursor sequence in the fallopian tube, culminating in serous tubal intraepithelial carcinoma (STIC), provides an opportunity to study early disease events. This study aims to explore novel metastatic routes in STICs. A BRCA1 mutation carrier (patient A) who presented with a STIC and tubal intraluminal shedding of tumor cells upon prophylactic bilateral salpingo-oophorectomy (PBSO) instigated scrutiny of an additional 23 women who underwent a PBSO and 40 patients with pelvic serous carcinoma involving the tubes. Complete serial sectioning of tubes and ovaries of patient A did not reveal invasive carcinoma, but subsequent staging surgery showed disseminated abdominal disease. STIC, intraluminal tumor cells, and abdominal metastases displayed an identical immunohistochemical profile (p53/WT1/PAX8/PAX2) and TP53 mutation. In 16 serous carcinoma patients (40%) tubal intraluminal tumor cells were found, compared with none in the PBSO group. This is the first description of a STIC, which plausibly metastasized without the presence of invasion through intraluminal shedding of malignant surface epithelial cells in the tube and subsequently spread throughout the peritoneal cavity. These findings warrant a reconsideration of the malignant potential of STICs and indicate that intraluminal shedding could be a risk factor for early intraperitoneal metastasis. Although rare in the absence of invasive cancer, we show that intraluminal shedding of tumor cells in the fallopian tubes from serous carcinoma cases are common and a likely route of abdominal spread.

  6. Modeling of transient ionizing radiation effects in bipolar devices at high dose-rates

    International Nuclear Information System (INIS)

    FJELDLY, T.A.; DENG, Y.; SHUR, M.S.; HJALMARSON, HAROLD P.; MUYSHONDT, ARNOLDO

    2000-01-01

    -n junctions was developed by Isaque et al. They used a more complete ambipolar transport equation, which included the dependencies of the transport parameters (ambipolar diffusion constant, mobility, and recombination rate) on the excess minority carrier concentration. The expression used for the recombination rate was that of Shockley-Reed-Hall (SRH) recombination which is dominant for low to mid-level radiation intensities. However, at higher intensities, Auger recombination becomes important eventually dominant. The complete ambipolar transport equation including the complicated dependence of transport parameters on the radiation intensity, cannot be solved analytically. This solution is obtained for each of the regimes where a given recombination mechanism dominates, and then by joining these solutions using appropriate smoothing functions. This approach allows them to develop a BJT model accounting for the photoelectric effect of the ionizing radiation that can be implemented in SPICE

  7. Performance of an LPD prototype detector at MHz frame rates under Synchrotron and FEL radiation

    Science.gov (United States)

    Koch, A.; Hart, M.; Nicholls, T.; Angelsen, C.; Coughlan, J.; French, M.; Hauf, S.; Kuster, M.; Sztuk-Dambietz, J.; Turcato, M.; Carini, G. A.; Chollet, M.; Herrmann, S. C.; Lemke, H. T.; Nelson, S.; Song, S.; Weaver, M.; Zhu, D.; Meents, A.; Fischer, P.

    2013-11-01

    A MHz frame rate X-ray area detector (LPD — Large Pixel Detector) is under development by the Rutherford Appleton Laboratory for the European XFEL. The detector will have 1 million pixels and allows analogue storage of 512 images taken at 4.5 MHz in the detector front end. The LPD detector has 500 μm thick silicon sensor tiles that are bump bonded to a readout ASIC. The ASIC's preamplifier provides relatively low noise at high speed which results in a high dynamic range of 105 photons over an energy range of 5-20 keV. Small scale prototypes of 32 × 256 pixels (LPD 2-Tile detector) and 256 × 256 pixels (LPD supermodule detector) are now available for X-ray tests. The performance of prototypes of the detector is reported for first tests under synchrotron radiation (PETRA III at DESY) and Free-Electron-Laser radiation (LCLS at SLAC). The initial performance of the detector in terms of signal range and noise, radiation hardness and spatial and temporal response are reported. The main result is that the 4.5 MHz sampling detection chain is reliably working, including the analogue on-chip memory concept. The detector is at least radiation hard up to 5 MGy at 12 keV. In addition the multiple gain concept has been demonstrated over a dynamic range to 104 at 12 keV with a readout noise equivalent to < 1 photon rms in its most sensitive mode.

  8. Acute intestinal injury induced by acetic acid and casein: prevention by intraluminal misoprostol

    International Nuclear Information System (INIS)

    Miller, M.J.; Zhang, x.J.; Gu, x.A.; Clark, D.A.

    1991-01-01

    Acute injury was established in anesthetized rabbits by intraluminal administration of acetic acid with and without bovine casein, into loops of distal small intestine. Damage was quantified after 45 minutes by the blood-to-lumen movement of 51 Cr-labeled ethylenediaminetetraacetic acid (EDTA) and fluorescein isothiocyanate-tagged bovine serum albumin as well as luminal fluid histamine levels. The amount of titratable acetic acid used to lower the pH of the treatment solutions to pH 4.0 was increased by the addition of calcium gluconate. Luminal acetic acid caused a 19-fold increase in 51 Cr-EDTA accumulation over saline controls; casein did not modify this effect. In saline controls, loop fluid histamine levels bordered on the limits of detection (1 ng/g) but were elevated 19-fold by acetic acid exposure and markedly increased (118-fold) by the combination of acid and casein. Intraluminal misoprostol (3 or 30 micrograms/mL), administered 30 minutes before acetic acid, significantly attenuated the increase in epithelial permeability (luminal 51 Cr-EDTA, fluorescein isothiocyanate-bovine serum albumin accumulation) and histamine release (P less than 0.05). Diphenhydramine, alone or in combination with cimetidine, and indomethacin (5 mg/kg IV) were not protective. It is concluded that exposure of the epithelium to acetic acid promotes the transepithelial movement of casein leading to enhanced mast cell activation and mucosal injury. Damage to the epithelial barrier can be prevented by misoprostol

  9. Treatment of 9 cases of pulmonary atelectasis caused by endobronchial tuberculosis with intraluminal stent implantation

    International Nuclear Information System (INIS)

    Ji Hongjiang; Li Qiang; Liu Zhongling; Bai Chong; Yao Xiaopeng; Zhao Lijun; Xu Hao; Dong Yuchao; Huang Haidong; Wang Qin

    2007-01-01

    Objective: To evaluate the effect and safety of intraluminal stent implantation in the treatment of complete airway obstruction with unilateral pulmonary atelectasis caused by endobronchial tuberculosis (EBTB). Methods: 9 cases of pulmonary atelectasis caused by EBTB were treated with high- frequency electricity/microwave, balloon dilation and endobronchial stent implantation. At the time of 1 week and 4-6 months after stenting ,the diameters of stenotic segment were measured. Results: All 9 cases with atelectasis of EBTB showed complete re-expansion within 3 days after the stent implantation. The mean diameter of the stenotic segments of 9 EBTB patients increased to 9.17 ± 1.24 mm at 7th day after stent implantation; 3 of 9 EBTB patients occured mild restenosis after implantation of tracheobronchial stents. However, combination therapy of cryotherapy and balloon dilation can effectively prevent the aggravation of restenosis. Conclusion: Comparing with traditional surgical treatment, the intraluminal stent implantation for atelectasis caused by EBTB is a new, effective, safe and microtraumatic method with reliable preservation of pulmonary function. (authors)

  10. Acute intestinal injury induced by acetic acid and casein: prevention by intraluminal misoprostol

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.J.; Zhang, x.J.; Gu, x.A.; Clark, D.A. (Department of Pediatrics, Louisiana State University School of Medicine, New Orleans (USA))

    1991-07-01

    Acute injury was established in anesthetized rabbits by intraluminal administration of acetic acid with and without bovine casein, into loops of distal small intestine. Damage was quantified after 45 minutes by the blood-to-lumen movement of {sup 51}Cr-labeled ethylenediaminetetraacetic acid (EDTA) and fluorescein isothiocyanate-tagged bovine serum albumin as well as luminal fluid histamine levels. The amount of titratable acetic acid used to lower the pH of the treatment solutions to pH 4.0 was increased by the addition of calcium gluconate. Luminal acetic acid caused a 19-fold increase in {sup 51}Cr-EDTA accumulation over saline controls; casein did not modify this effect. In saline controls, loop fluid histamine levels bordered on the limits of detection (1 ng/g) but were elevated 19-fold by acetic acid exposure and markedly increased (118-fold) by the combination of acid and casein. Intraluminal misoprostol (3 or 30 micrograms/mL), administered 30 minutes before acetic acid, significantly attenuated the increase in epithelial permeability (luminal {sup 51}Cr-EDTA, fluorescein isothiocyanate-bovine serum albumin accumulation) and histamine release (P less than 0.05). Diphenhydramine, alone or in combination with cimetidine, and indomethacin (5 mg/kg IV) were not protective. It is concluded that exposure of the epithelium to acetic acid promotes the transepithelial movement of casein leading to enhanced mast cell activation and mucosal injury. Damage to the epithelial barrier can be prevented by misoprostol.

  11. Explanation of enhanced mechanical degradation rate for radiation- aged polyolefins as the aging temperature is decreased

    International Nuclear Information System (INIS)

    Gillen, K.T.; Clough, R.L.; Wise, J.; Malone, M.G.

    1994-01-01

    Degradation rates are normally increased by increasing the responsible environmental stresses. We describe results for a semi-crystalline, crosslinked polyolefin material that contradicts this assumption. In particular, under combined radiation plus thermal environments, this material mechanically degrades much faster at room temperature than it does at elevated temperatures. The probable explanation for this phenomenon relates to the importance on mechanical properties of the tie molecules connecting crystalline and amorphous regions. Partial melting and reforming/ reorganization of crystallites occurs throughout the crystalline melting region (at least room temperature up to 126 C), with the rate of such processes increasing with an increase in temperature. At low temperatures, this process is sufficiently slow such that a large percentage of the radiation-damaged tie molecules will still connect the amorphous and crystalline regions at the end of aging, leading to rapid reductions in tensile properties. At higher temperatures, the enhanced annealing rate will lead, during the aging, to the establishment of new, undamaged tie molecules connecting crystalline and amorphous regions. This healing process will reduce the degradation rate. Evidence in support of this model is presented

  12. Contribution to the study of the behaviour of polluted atmospheres under low β radiation rates

    International Nuclear Information System (INIS)

    Colin, J.P.

    1981-01-01

    In some cases where nuclear power plants are built in industrial areas, radiochemical impacts might occur at the same time as radiobiological impacts. These radiochemical impacts would be due to interactions between gaseous radioactive emissions and pollutants of the ambient atmosphere in these areas. Fundamental data needed for evaluating this have been brought together in this paper. The published data on air radiochemistry are discussed in detail, particularly for low radiation rates and low pollutant levels. But generally, published data appear to be plainly insufficient because of the high level of radiation rates and concentrations, particularly for NOsub(x). So the experimental study concerns nitrogen oxides mainly. Mixtures with concentration of about 1 ppmV of NO 2 , NO or SO 2 are irradiated, in a glass chamber, by β radiations from krypton 85. Mixtures are analyzed after various time lapses. The irradiation of NO and NO 2 polluted air leads to a progressive disappearance of NO and NO 2 and to the formation of a great amount of O 3 and N 2 O 5 (so the total amount of nitrogen oxides is increasing). Results can be explained with a radicalar model. With water vapor, the disappearance speed of NO and NO 2 is increased, the formation speed of O 3 is reduced. Some results of SO 2 irradiation are given [fr

  13. Analysis and radiation dose rate measurement of the Al-1050 capsule on the rabbit system facility

    International Nuclear Information System (INIS)

    Sarwani; Sutrisno; H, Saleh; Rohidi; M, Kawkab

    2000-01-01

    Aluminium is a kind of light metal with density of 2.7 gram /cm exp 3,regarding to the aluminium is characteristic such as easy to fabricated,has a good corrosion resistant and radiation heat resistant, therefore aluminum is selected to be used as a material for sample irradiation capsule with high neutron fluency. Analysis using neutron activation method and capsule irradiation by using high neutron fluency and dose radiation rate measurement was done. The analysis result show that impurities in the Al-1050 capsule are Fe, Cu, Mg, Sb, Zn, and Mn. The capsule irradiated at 15 MW during 6 Hours with neutron fluency of 2,8 x 10 exp 17 n/cm exp 2. The radiation doses rate after 24 hours decay is 220 mrad/h at 0-meter distance and 60 mrad/h at 1-meter distance. Respectively. From the analysis results and measurement show that the Al-1050 capsule has no high neutron absorption element and available to get continuing irradiation at 15 MW as far as 6 hours. Due to the personal safety, therefore the capsule handling could be carried out in the hot cell

  14. Delayed Workforce Entry and High Emigration Rates for Recent Canadian Radiation Oncology Graduates

    Energy Technology Data Exchange (ETDEWEB)

    Loewen, Shaun K., E-mail: shaun.loewen@cancercare.mb.ca [CancerCare Manitoba, Winnipeg, MB (Canada); Halperin, Ross; Lefresne, Shilo [BC Cancer Agency, Vancouver, BC (Canada); Trotter, Theresa [Tom Baker Cancer Centre, Calgary, AB (Canada); Stuckless, Teri [Dr H. Bliss Murphy Cancer Centre, St. John' s, NL (Canada); Brundage, Michael [Cancer Centre of Southeastern Ontario, Kingston, ON (Canada)

    2015-10-01

    Purpose: To determine the employment status and location of recent Canadian radiation oncology (RO) graduates and to identify current workforce entry trends. Methods and Materials: A fill-in-the-blank spreadsheet was distributed to all RO program directors in December 2013 and June 2014, requesting the employment status and location of their graduates over the last 3 years. Visa trainee graduates were excluded. Results: Response rate from program directors was 100% for both survey administrations. Of 101 graduates identified, 99 (98%) had known employment status and location. In the December survey, 5 2013 graduates (16%), 17 2012 graduates (59%), and 18 2011 graduates (75%) had permanent staff employment. Six months later, 5 2014 graduates (29%), 15 2013 graduates (48%), 24 2012 graduates (83%), and 21 2011 graduates (88%) had secured staff positions. Fellowships and temporary locums were common for those without staff employment. The proportion of graduates with staff positions abroad increased from 22% to 26% 6 months later. Conclusions: Workforce entry for most RO graduates was delayed but showed steady improvement with longer time after graduation. High emigration rates for jobs abroad signify domestic employment challenges for newly certified, Canadian-trained radiation oncologists. Coordination on a national level is required to address and regulate radiation oncologist supply and demand disequilibrium in Canada.

  15. Ionizing radiation sensitivity and the rate of gross chromosomal rearrangement in yeast

    International Nuclear Information System (INIS)

    Brown, J.A.; Brown, M.

    2003-01-01

    Full text: Many of the genes conferring resistance to DNA damage in the yeast Saccharomyces cerevisiae have been identified. The systematic deletion of every open reading frame presents the opportunity to make great strides in determining the physiological role of many genes whose function has remained elusive. The ability to discriminate among all of the strains carrying unique non-essential gene deletions in a pool has allowed us to screen for novel genes required for survival to ionizing radiation. Many of these genes have not yet been characterized. A possible role for these genes could be in the initial sensing of the double strand break introduced by ionizing radiation, the cell cycle arrest permitting the cell time for the repair process, or directly in the repair. A consequence of a failure of any of these functions could result in an increase in mutation rate as well the more detrimental gross chromosomal rearrangement (GCR). We tested the hypothesis that any gene which when deleted caused an increase in ionizing radiation sensitivity would also demonstrate an increase in mutation rate and GCR. This turned out not to be the case with many having no significant increase and one in particular which caused a significant decrease in GCR. Data on several of the more intriguing genes will be presented

  16. Delayed Workforce Entry and High Emigration Rates for Recent Canadian Radiation Oncology Graduates.

    Science.gov (United States)

    Loewen, Shaun K; Halperin, Ross; Lefresne, Shilo; Trotter, Theresa; Stuckless, Teri; Brundage, Michael

    2015-10-01

    To determine the employment status and location of recent Canadian radiation oncology (RO) graduates and to identify current workforce entry trends. A fill-in-the-blank spreadsheet was distributed to all RO program directors in December 2013 and June 2014, requesting the employment status and location of their graduates over the last 3 years. Visa trainee graduates were excluded. Response rate from program directors was 100% for both survey administrations. Of 101 graduates identified, 99 (98%) had known employment status and location. In the December survey, 5 2013 graduates (16%), 17 2012 graduates (59%), and 18 2011 graduates (75%) had permanent staff employment. Six months later, 5 2014 graduates (29%), 15 2013 graduates (48%), 24 2012 graduates (83%), and 21 2011 graduates (88%) had secured staff positions. Fellowships and temporary locums were common for those without staff employment. The proportion of graduates with staff positions abroad increased from 22% to 26% 6 months later. Workforce entry for most RO graduates was delayed but showed steady improvement with longer time after graduation. High emigration rates for jobs abroad signify domestic employment challenges for newly certified, Canadian-trained radiation oncologists. Coordination on a national level is required to address and regulate radiation oncologist supply and demand disequilibrium in Canada. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Delayed Workforce Entry and High Emigration Rates for Recent Canadian Radiation Oncology Graduates

    International Nuclear Information System (INIS)

    Loewen, Shaun K.; Halperin, Ross; Lefresne, Shilo; Trotter, Theresa; Stuckless, Teri; Brundage, Michael

    2015-01-01

    Purpose: To determine the employment status and location of recent Canadian radiation oncology (RO) graduates and to identify current workforce entry trends. Methods and Materials: A fill-in-the-blank spreadsheet was distributed to all RO program directors in December 2013 and June 2014, requesting the employment status and location of their graduates over the last 3 years. Visa trainee graduates were excluded. Results: Response rate from program directors was 100% for both survey administrations. Of 101 graduates identified, 99 (98%) had known employment status and location. In the December survey, 5 2013 graduates (16%), 17 2012 graduates (59%), and 18 2011 graduates (75%) had permanent staff employment. Six months later, 5 2014 graduates (29%), 15 2013 graduates (48%), 24 2012 graduates (83%), and 21 2011 graduates (88%) had secured staff positions. Fellowships and temporary locums were common for those without staff employment. The proportion of graduates with staff positions abroad increased from 22% to 26% 6 months later. Conclusions: Workforce entry for most RO graduates was delayed but showed steady improvement with longer time after graduation. High emigration rates for jobs abroad signify domestic employment challenges for newly certified, Canadian-trained radiation oncologists. Coordination on a national level is required to address and regulate radiation oncologist supply and demand disequilibrium in Canada

  18. On-line statistical processing of radiation detector pulse trains with time-varying count rates

    International Nuclear Information System (INIS)

    Apostolopoulos, G.

    2008-01-01

    Statistical analysis is of primary importance for the correct interpretation of nuclear measurements, due to the inherent random nature of radioactive decay processes. This paper discusses the application of statistical signal processing techniques to the random pulse trains generated by radiation detectors. The aims of the presented algorithms are: (i) continuous, on-line estimation of the underlying time-varying count rate θ(t) and its first-order derivative dθ/dt; (ii) detection of abrupt changes in both of these quantities and estimation of their new value after the change point. Maximum-likelihood techniques, based on the Poisson probability distribution, are employed for the on-line estimation of θ and dθ/dt. Detection of abrupt changes is achieved on the basis of the generalized likelihood ratio statistical test. The properties of the proposed algorithms are evaluated by extensive simulations and possible applications for on-line radiation monitoring are discussed

  19. Brachytherapy. High dose rate brachytherapy - Radiation protection: medical sheet ED 4287

    International Nuclear Information System (INIS)

    Celier, D.; Aubert, B.; Vidal, J.P.; Biau, A.; Lahaye, T.; Gauron, C.; Barret, C.; Boisserie, G.; Branchet, E.; Gambini, D.; Gondran, C.; Le Guen, B.; Guerin, C.; Nguyen, S.; Pierrat, N.; Sarrazin, T.; Donnarieix, D.

    2010-02-01

    After having indicated the required authorization to implement brachytherapy techniques, this document presents the various aspects and measures related to radiation protection when performing high-dose-rate brachytherapy treatments. It presents the concerned personnel, describes the operational process, indicates the associated hazards and the risk related to ionizing radiation, and describes how the risk is to be assessed and how exposure levels are to be determined (elements of risk assessment, delimitation of controlled and monitored areas, personnel classification, and choice of the dose monitoring method). It describes the various components of a risk management strategy (risk reduction, technical measures regarding the installation and the personnel, training and information, prevention and medical monitoring). It briefly presents how risk management is to be assessed, and mentions other related risks (biological risk, handling and posture, handling of heavy loads, mental workload, chemical risk)

  20. Brachytherapy. Pulsed dose rate brachytherapy - Radiation protection: medical sheet ED 4250

    International Nuclear Information System (INIS)

    Celier, D.; Aubert, B.; Vidal, J.P.; Biau, A.; Lahaye, T.; Gauron, C.; Barret, C.; Boisserie, G.; Branchet, E.; Gambini, D.; Gondran, C.; Le Guen, B.; Guerin, C.; Nguyen, S.; Pierrat, N.; Sarrazin, T.; Donnarieix, D.

    2009-06-01

    After having indicated the required authorization to implement brachytherapy techniques, this document presents the various aspects and measures related to radiation protection when performing pulsed-dose-rate brachytherapy treatments. It presents the concerned personnel, describes the operational process, indicates the associated hazards and the risk related to ionizing radiation, and describes how the risk is to be assessed and how exposure levels are to be determined (elements of risk assessment, delimitation of controlled and monitored areas, personnel classification, and choice of the dose monitoring method). It describes the various components of a risk management strategy (risk reduction, technical measures regarding the installation and the personnel, training and information, prevention and medical monitoring). It briefly presents how risk management is to be assessed, and mentions other related risks (biological risk, handling and posture, handling of heavy loads, mental workload, chemical risk)

  1. Effects of dose, dose-rate and fraction on radiation-induced breast and lung cancers

    International Nuclear Information System (INIS)

    Howe, G.R.

    1992-01-01

    Recent results from a large Canadian epidemiologic cohort study of low-LET radiation and cancer will be described. This is a study of 64,172 tuberculosis patients first treated in Canada between 1930 and 1952, of whom many received substantial doses to breast and lung tissue from repeated chest fluoroscopies. The mortality of the cohort between 1950 and 1987 has been determined by computerized record linkage to the National Mortality Data Base. There is a strong positive association between radiation and breast cancer risk among the females in the cohort, but in contrast very little evidence of any increased risk in lung cancer. The results of this and other studies suggest that the effect of dose-rate and/or fractionation on cancer risk may will differ depending upon the particular cancer being considered. (author)

  2. Development of gas micro-strip chambers for high rate radiation detection and tracking

    CERN Document Server

    Bouclier, Roger; Gaudaen, J; Florent, J J; Ropelewski, Leszek; Sauli, Fabio; Bondar, A E; Groshev, V R; Minakov, G D; Onuchin, A P; Pestov, Yu N; Shekhtman, L I; Sidorov, V A; Dixit, M S; Oakham, G K; Møller, S; Sørensen, G; Uggerhøj, Erik; Brons, S; Brückner, W; Godbersen, M; Heidrich, M; Paul, S; Trombini, A; Werding, R; Armitage, J A; Karlen, D A; Stewart, G; Barasch, E F; McIntyre, P; Pang, Y; Trost, H J; Salomon, M; Breskin, Amos; Chechik, R; Pansky, A; CERN. Geneva. Detector Research and Development Committee

    1992-01-01

    Gas Micro-Strip Chambers (GMSC) are a promising high-rate, high resolution position detector suited for use in high luminosity hadron collider experiments, as general purpose tracker or to improve the performances of pre-shower counters, transition radiation and inner muon detectors. Large GMSC arrays have been included in proposed LHC and SSC experimental setups. The operating characteristics of GMSC make their use very attractive also for detectors at tau/charm/beauty factories, as well as for synchrotron radiation facilities and for medical applications. At the present state of the art, some problems limiting the usefulness of microstrip chambers are the observed gain changes due to charging up of the support, possible long-term degradation due to ageing, limited sizes imposed by fabrication technologies and unavailability of dedicated high-speed, high-density readout electronics. Limited experience exists of operation of GMSC in real experimental conditions, and little if anything is known about performan...

  3. Development of Gas Micro-Strip Chambers for Radiation Detection and Tracking at High Rates

    CERN Multimedia

    2002-01-01

    % RD28 \\\\ \\\\ Micro-Strip Gas Chambers (GMSC) are a promising high rate, high resolution position detector suited for use in high luminosity hadron collider experiments, as general purpose tracker or to improve the performances of preshower counters, transition radiation and inner muon detectors. Large GMSC arrays have been included in proposed LHC and SSC experimental setups. The operating characteristics of GMSC make their use very attractive also for detectors at tau/beauty/charm factories, as well as for synchrotron radiation facilities and medical applications. At the present state of the art, some problems limiting the usefulness of microstrip chambers are the observed gain changes due to charging up of the support, possible long-term degradation due to ageing, limited sizes imposed by fabrication technologies and unavailability of dedicated high-speed, high-density readout electronics. Limited experience exists of operation of GMSC in real experimental conditions, and little if anything is known about p...

  4. Distributed optical fibre temperature measurements in a low dose rate radiation environment based on Rayleigh backscattering

    Science.gov (United States)

    Faustov, A.; Gussarov, A.; Wuilpart, M.; Fotiadi, A. A.; Liokumovich, L. B.; Kotov, O. I.; Zolotovskiy, I. O.; Tomashuk, A. L.; Deschoutheete, T.; Mégret, P.

    2012-04-01

    On-line monitoring of environmental conditions in nuclear facilities is becoming a more and more important problem. Standard electronic sensors are not the ideal solution due to radiation sensitivity and difficulties in installation of multiple sensors. In contrast, radiation-hard optical fibres can sustain very high radiation doses and also naturally offer multi-point or distributed monitoring of external perturbations. Multiple local electro-mechanical sensors can be replaced by just one measuring fibre. At present, there are over four hundred operational nuclear power plants (NPPs) in the world 1. Operating experience has shown that ineffective control of the ageing degradation of major NPP components can threaten plant safety and also plant life. Among those elements, cables are vital components of I&C systems in NPPs. To ensure their safe operation and predict remaining life, environmental monitoring is necessary. In particular, temperature and radiation dose are considered to be the two most important parameters. The aim of this paper is to assess experimentally the feasibility of optical fibre temperature measurements in a low doserate radiation environment, using a commercially available reflectometer based on Rayleigh backscattering. Four different fibres were installed in the Sub-Pile Room of the BR2 Material testing nuclear reactor in Mol, Belgium. This place is man-accessible during the reactor shut-down, allowing easy fibre installation. When the reactor operates, the dose-rates in the room are in a range 0.005-5 Gy/h with temperatures of 40-60 °C, depending on the location. Such a surrounding is not much different to some "hot" environments in NPPs, where I&C cables are located.

  5. Altering the Rate of Mitosis by Introducing Low-Gigahertz Radiation to Saccharomyces cerevisiae Cells

    Science.gov (United States)

    Garg, S.; Ashby, C.

    2017-12-01

    This experiment aims to assess the impact of low-frequency radiation (from common technological tools such as cell phones, scanners, and wifi) on the mitotic rates of cells. In particular, the focus of the study was on the growth and development of Saccharomyces cerevisiae cultures that were exposed to radio waves from a wifi router, which were then compared to a cohort of the same species without exposure. Though routers emit a low gigahertz frequency, they are categorized as Group 2B radiation (possibly carcinogenic) by the International Agency for Research on Cancer of the World Health Organization, signifying that constant exposure poses a potential risk to humans. Twelve agar dishes of active Saccharomyces cerevisiae solution were prepared, with six dishes acting as the control under no added radiation and six acting as the experimental group under 2.4 GHz of radiation due to their proximity to the router. Data on how many cultures proliferated in each dish was collected every three days, with the experiment running for a total of twelve days. All subjects experienced growth curves until day 9 when the experimental group's growth peaked with an average of 62 colonies/dish. Three of the six dishes in this group lost colonies in the following three days, leaving the experimental group with an average of 61 colonies/dish on day 12, while the control group was still increasing by day 12 with an average of 48 colonies/dish, with only one dish undergoing a loss of colonies. Exposing the Saccharomyces cerevisiae cells to low grade radiation resulted in accelerated mitosis, and though the experimental group faced colony death after nine days, the loss was likely due to overpopulation in the dish.

  6. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  7. Radiative recombination of highly charged ions: Enhanced rates at low energies

    International Nuclear Information System (INIS)

    Frank, A.; Mueller, A.; Haselbauer, J.; Schennach, S.; Spies, W.; Uwira, O.; Wagner, M.

    1992-01-01

    In a single-pass merged-beams experiment employing a dense cold electron target recombination of highly charged ions is studied. Unexpected high recombination rates are observed at low energies E cm in the electron-ion center-of-mass frame. In particular, theoretical estimates for radiative recombination are dramatically exceeded by the experimental recombination rates at E cm =0 eV for U 28+ and for Au 25+ ions. Considerable rate enhancement is also observed for Ar 15+ . This points to a general phenomenon which has to be interpreted as a consequence of high electron densities, low electron beam temperatures, high ion charge states and presence of strong magnetic fields. (orig.)

  8. Evaluation of radiation shielding rate of lead aprons in nuclear medicine

    International Nuclear Information System (INIS)

    Han, Sang Hyun; Han, Beom Heui; Lee, Sang Ho; Hong, Dong Heui; Kim, Gi Jin

    2017-01-01

    Considering that the X-ray apron used in the department of radiology is also used in the department of nuclear medicine, the study aimed to analyze the shielding rate of the apron according to types of radioisotopes, thus γ ray energy, to investigate the protective effects. The radioisotopes used in the experiment were the top 5 nuclides in usage statistics "9"9"mTc, "1"8F, "1"3"1I, "1"2"3I, and "2"0"1Tl, and the aprons were lead equivalent 0.35 mmPb aprons currently under use in the department of nuclear medicine. As a result of experiments, average shielding rates of aprons were "9"9"mTc 31.59%, "2"0"1Tl 68.42%, and "1"2"3I 76.63%. When using an apron, the shielding rate of "1"3'1I actually resulted in average dose rate increase of 33.72%, and "1"8F showed an average shielding rate of –0.315%, showing there was almost no shielding effect. As a result, the radioisotopes with higher shielding rate of apron was in the descending order of "1"2"3I, "2"0"1Tl, "9"9"mTc, "1"8F, "1"3"1I. Currently, aprons used in the nuclear medicine laboratory are general X-ray aprons, and it is thought that it is not appropriate for nuclear medicine environment that utilizes γ rays. Therefore, development of nuclear medicine exclusive aprons suitable for the characteristics of radioisotopes is required in consideration of effective radiation protection and work efficiency of radiation workers

  9. Evaluation of radiation shielding rate of lead aprons in nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang Hyun; Han, Beom Heui; Lee, Sang Ho [Dept. of Radiological Science, Seonam University, Asan (Korea, Republic of); Hong, Dong Heui [Dept. of Radiological Science, Far East University, Eumseong (Korea, Republic of); Kim, Gi Jin [Dept. of Nuclear Medicine, Konyang University Hospital, Daejeon (Korea, Republic of)

    2017-03-15

    Considering that the X-ray apron used in the department of radiology is also used in the department of nuclear medicine, the study aimed to analyze the shielding rate of the apron according to types of radioisotopes, thus γ ray energy, to investigate the protective effects. The radioisotopes used in the experiment were the top 5 nuclides in usage statistics {sup 99m}Tc, {sup 18}F, {sup 131}I, {sup 123}I, and {sup 201}Tl, and the aprons were lead equivalent 0.35 mmPb aprons currently under use in the department of nuclear medicine. As a result of experiments, average shielding rates of aprons were {sup 99m}Tc 31.59%, {sup 201}Tl 68.42%, and {sup 123}I 76.63%. When using an apron, the shielding rate of {sup 13}'1I actually resulted in average dose rate increase of 33.72%, and {sup 18}F showed an average shielding rate of –0.315%, showing there was almost no shielding effect. As a result, the radioisotopes with higher shielding rate of apron was in the descending order of {sup 123}I, {sup 201}Tl, {sup 99m}Tc, {sup 18}F, {sup 131}I. Currently, aprons used in the nuclear medicine laboratory are general X-ray aprons, and it is thought that it is not appropriate for nuclear medicine environment that utilizes γ rays. Therefore, development of nuclear medicine exclusive aprons suitable for the characteristics of radioisotopes is required in consideration of effective radiation protection and work efficiency of radiation workers.

  10. Dose rate effects of low-LET ionizing radiation on fish cells

    Energy Technology Data Exchange (ETDEWEB)

    Vo, Nguyen T.K. [McMaster University, Radiation Sciences Program, School of Graduate and Postdoctoral Studies, Hamilton, ON (Canada); Seymour, Colin B.; Mothersill, Carmel E. [McMaster University, Radiation Sciences Program, School of Graduate and Postdoctoral Studies, Hamilton, ON (Canada); McMaster University, Department of Biology, Hamilton, ON (Canada)

    2017-11-15

    Radiobiological responses of a highly clonogenic fish cell line, eelB, to low-LET ionizing radiation and effects of dose rates were studied. In acute exposure to 0.1-12 Gy of gamma rays, eelB's cell survival curve displayed a linear-quadratic (LQ) relationship. In the LQ model, α, β, and α/β ratio were 0.0024, 0.037, and 0.065, respectively; for the first time that these values were reported for fish cells. In the multi-target model, n, D{sub o}, and D{sub q} values were determined to be 4.42, 2.16, and 3.21 Gy, respectively, and were the smallest among fish cell lines being examined to date. The mitochondrial potential response to gamma radiation in eelB cells was at least biphasic: mitochondria hyperpolarized 2 h and then depolarized 5 h post-irradiation. Upon receiving gamma rays with a total dose of 5 Gy, dose rates (ranging between 83 and 1366 mGy/min) had different effects on the clonogenic survival but not the mitochondrial potential. The clonogenic survival was significantly higher at the lowest dose rate of 83 mGy/min than at the other higher dose rates. Upon continuous irradiation with beta particles from tritium at 0.5, 5, 50, and 500 mGy/day for 7 days, mitochondria significantly depolarized at the three higher dose rates. Clearly, dose rates had differential effects on the clonogenic survival of and mitochondrial membrane potential in fish cells. (orig.)

  11. Circumferential targeted renal sympathetic nerve denervation with preservation of the renal arterial wall using intra-luminal ultrasound

    Science.gov (United States)

    Roth, Austin; Coleman, Leslie; Sakakura, Kenichi; Ladich, Elena; Virmani, Renu

    2015-03-01

    An intra-luminal ultrasound catheter system (ReCor Medical's Paradise System) has been developed to provide circumferential denervation of the renal sympathetic nerves, while preserving the renal arterial intimal and medial layers, in order to treat hypertension. The Paradise System features a cylindrical non-focused ultrasound transducer centered within a balloon that circulates cooling fluid and that outputs a uniform circumferential energy pattern designed to ablate tissues located 1-6 mm from the arterial wall and protect tissues within 1 mm. RF power and cooling flow rate are controlled by the Paradise Generator which can energize transducers in the 8.5-9.5 MHz frequency range. Computer simulations and tissue-mimicking phantom models were used to develop the proper power, cooling flow rate and sonication duration settings to provide consistent tissue ablation for renal arteries ranging from 5-8 mm in diameter. The modulation of these three parameters allows for control over the near-field (border of lesion closest to arterial wall) and far-field (border of lesion farthest from arterial wall, consisting of the adventitial and peri-adventitial spaces) depths of the tissue lesion formed by the absorption of ultrasonic energy and conduction of heat. Porcine studies have confirmed the safety (protected intimal and medial layers) and effectiveness (ablation of 1-6 mm region) of the system and provided near-field and far-field depth data to correlate with bench and computer simulation models. The safety and effectiveness of the Paradise System, developed through computer model, bench and in vivo studies, has been demonstrated in human clinical studies.

  12. Radiation

    International Nuclear Information System (INIS)

    Winther, J.F.; Ulbak, K.; Dreyer, L.; Pukkala, E.; Oesterlind, A.

    1997-01-01

    Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all malignant melanomas arising in the Nordic populations around the year 2000 will be due to exposure to natural ultraviolet radiation, equivalent to an annual number of about 4700 cases, with 2100 in men and 2600 in women, or some 4% of all cancers notified. Exposure to ionizing radiation in the Nordic countries occurs at an average effective dose per capita per year of about 3 mSv (Iceland, 1.1 mSv) from natural sources, and about 1 mSv from man-made sources. While the natural sources are primarily radon in indoor air, natural radionuclides in food, cosmic radiation and gamma radiation from soil and building materials, the man-made sources are dominated by the diagnostic and therapeutic use of ionizing radiation. On the basis of measured levels of radon in Nordic dwellings and associated risk estimates for lung cancer derived from well-conducted epidemiological studies, we estimated that about 180 cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120

  13. [Effects of reduced solar radiation on winter wheat flag leaf net photosynthetic rate].

    Science.gov (United States)

    Zheng, You-Fei; Ni, Yan-Li; Mai, Bo-Ru; Wu, Rong-Jun; Feng, Yan; Sun, Jian; Li, Jian; Xu, Jing-Xin

    2011-06-01

    Taking winter wheat Triticum aestivum L. (cv. Yangmai 13) as test material, a field experiment was conducted in Nanjing City to study the effects of simulated reduced solar radiation on the diurnal variation of winter wheat flag leaf photosynthetic rate and the main affecting factors. Five treatments were installed, i. e., 15% (T15), 20% (T20) , 40% (T40), 60% (T60), and 100% (CK) of total incident solar radiation. Reduced solar irradiance increased the chlorophyll and lutein contents significantly, but decreased the net photosynthetic rate (Pn). Under different solar irradiance, the diurnal variation of Pn had greater difference, and the daily maximum Pn was in the order of CK > T60 > T40 > T 20 > T15. In CK, the Pn exhibited a double peak diurnal curve; while in the other four treatments, the Pn showed a single peak curve, and the peak was lagged behind that of CK. Correlation analysis showed that reduced solar irradiance was the main factor affecting the diurnal variation of Pn, but the physiological parameters also played important roles in determining the diurnal variation of Pn. In treatments T60 and T40, the photosynthesis active radiation (PAR), leaf temperature (T1) , stomatal conductance (Gs) , and transpiration rate (Tr) were significantly positively correlated with Pn, suggesting their positive effects on Pn. The intercellular CO2 concentration (Ci) and stomatal limitation (Ls) had significant negative correlations with Pn in treatments T60 and T40 but significant positive correlations with Pn in treatments T20 and T15, implying that the Ci and Ls had negative (or positive) effects on Pn when the solar irradiance was higher (or lower) than 40% of incident solar irradiance.

  14. Impact of heart rate and rhythm on radiation exposure in prospectively ECG triggered computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Luecke, Christian, E-mail: neep@gmx.de [University of Leipzig – Heart Center, Department of Diagnostic and Interventional Radiology, Strümpellstrasse 39, D-04289, Leipzig (Germany); Andres, Claudia; Foldyna, Borek [University of Leipzig – Heart Center, Department of Diagnostic and Interventional Radiology, Strümpellstrasse 39, D-04289, Leipzig (Germany); Nagel, Hans Dieter [Wissenschaft and Technik für die Radiologie, Buchhholz i.d.N (Germany); Hoffmann, Janine; Grothoff, Matthias; Nitzsche, Stefan; Gutberlet, Matthias; Lehmkuhl, Lukas [University of Leipzig – Heart Center, Department of Diagnostic and Interventional Radiology, Strümpellstrasse 39, D-04289, Leipzig (Germany)

    2012-09-15

    Purpose: To evaluate the influence of different heart rates and arrhythmias on scanner performance, image acquisition and applied radiation exposure in prospectively ECG triggered computed tomography (pCT). Materials and methods: An ECG simulator (EKG Phantom 320, Müller and Sebastiani Elektronik GmbH, Munich, Germany) was used to generate different heart rhythms and arrhythmias: sinus rhythm (SR) at 45, 60, 75, 90 and 120/min, supraventricular arrhythmias (e.g. sinus arrhythmia, atrial fibrillation) and ventricular arrhythmias (e.g. ventricular extrasystoles), pacemaker-ECGs, ST-changes and technical artifacts. The analysis of the image acquisition process was performed on a 64-row multidetector CT (Brilliance, Philips Medical Systems, Cleveland, USA). A prospectively triggered scan protocol as used for routine was applied (120 kV; 150 mA s; 0.4 s rotation and exposure time per scan; image acquisition predominantly in end-diastole at 75% R-R-interval, in arrythmias with a mean heart rate above 80/min in systole at 45% of the R-R-interval; FOV 25 cm). The mean dose length product (DLP) and its percentage increase from baseline (SR at 60/min) were determined. Result: Radiation exposure can increase significantly when the heart rhythm deviates from sinus rhythm. ECG-changes leading to a significant DLP increase (p < 0.05) were bifocal pacemaker (61%), pacemaker dysfunction (22%), SVES (20%), ventricular salvo (20%), and atrial fibrillation (14%). Significantly (p < 0.05) prolonged scan time (>8 s) could be observed in bifocal pacemaker (12.8 s), pacemaker dysfunction (10.7 s), atrial fibrillation (10.3 s) and sinus arrhythmia (9.3 s). Conclusion: In prospectively ECG triggered CT, heart rate and rhythm can provoke different types of scanner performance, which can significantly alter radiation exposure and scan time. These results might have an important implication for indication, informed consent and contrast agent injection protocols.

  15. Impact of heart rate and rhythm on radiation exposure in prospectively ECG triggered computed tomography

    International Nuclear Information System (INIS)

    Luecke, Christian; Andres, Claudia; Foldyna, Borek; Nagel, Hans Dieter; Hoffmann, Janine; Grothoff, Matthias; Nitzsche, Stefan; Gutberlet, Matthias; Lehmkuhl, Lukas

    2012-01-01

    Purpose: To evaluate the influence of different heart rates and arrhythmias on scanner performance, image acquisition and applied radiation exposure in prospectively ECG triggered computed tomography (pCT). Materials and methods: An ECG simulator (EKG Phantom 320, Müller and Sebastiani Elektronik GmbH, Munich, Germany) was used to generate different heart rhythms and arrhythmias: sinus rhythm (SR) at 45, 60, 75, 90 and 120/min, supraventricular arrhythmias (e.g. sinus arrhythmia, atrial fibrillation) and ventricular arrhythmias (e.g. ventricular extrasystoles), pacemaker-ECGs, ST-changes and technical artifacts. The analysis of the image acquisition process was performed on a 64-row multidetector CT (Brilliance, Philips Medical Systems, Cleveland, USA). A prospectively triggered scan protocol as used for routine was applied (120 kV; 150 mA s; 0.4 s rotation and exposure time per scan; image acquisition predominantly in end-diastole at 75% R-R-interval, in arrythmias with a mean heart rate above 80/min in systole at 45% of the R-R-interval; FOV 25 cm). The mean dose length product (DLP) and its percentage increase from baseline (SR at 60/min) were determined. Result: Radiation exposure can increase significantly when the heart rhythm deviates from sinus rhythm. ECG-changes leading to a significant DLP increase (p 8 s) could be observed in bifocal pacemaker (12.8 s), pacemaker dysfunction (10.7 s), atrial fibrillation (10.3 s) and sinus arrhythmia (9.3 s). Conclusion: In prospectively ECG triggered CT, heart rate and rhythm can provoke different types of scanner performance, which can significantly alter radiation exposure and scan time. These results might have an important implication for indication, informed consent and contrast agent injection protocols

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

    Energy Technology Data Exchange (ETDEWEB)

    Damkaer, D.M.; Dey, D.B.; Heron, G.A.

    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/sup -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/sup -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.

  17. Set of programs for determining exposure and dose rates from selected sources of gamma radiation

    International Nuclear Information System (INIS)

    Hep, J.; Kralovcova, E.; Smutny, V.; Valenta, V.

    1982-01-01

    The programs are described for the determination of exposure and dose rate of gamma radiation from point, surface, linear and volume sources with and without shielding. The computation is conducted using the classical method taking into consideration the buildup factor. For the computation of the buildup factor in heterogeneous shielding the Broder and Kitazuma formulas are used. Kitazuma's alpha coefficients were calculated recurrently using a new semi-empirical method. Taylor's approximation was used for the calculation of the buildup factor in a single layer

  18. Radiation-induced inheritable changes in the death-rate of cells

    International Nuclear Information System (INIS)

    Bychkovskaya, I.B.; Ochinskaya, G.K.

    1980-01-01

    By the use of an original technique (regeneration of individual lines from sister cells) it was demonstrated on various individually cultivated protozoa (Amoeba proteus, Paramecium caudatum and Climacostomum virens) that even weak direct and indirect radiation effects can induce an appreciable increase in the death-rate of descendants. After a certain dose threshold, the effect did not depend on the power of the attack and remained at the same level for as long as 3 years. The observed changes were qualitatively different from known types of inheritable changes leading to cell death

  19. Radiation induced skeletal changes in beagle: dose rates, dose, and age effect analysis from 226Ra

    International Nuclear Information System (INIS)

    Momeni, M.H.; Williams, J.R.; Rosenblatt, L.S.

    1976-01-01

    Radiation-induced skeletal injury (E) and the rate of skeletal injury were studied as a function of time and dose in beagles administered 226 Ra Cl 2 in eight semimonthly iv injections starting at 2, 4, or 14 months of age. Skeletal changes were evaluated with a radiographic x-ray scoring system in 20 skeletal regions; each region was scored on a 0 to 6 scale. Bone changes in six regions of humeri were qualitatively analyzed for comparison with total skeletal changes. Skeletal changes were classified by endosteal or periosteal cortical sclerosis and thickening, fractures, osteolytic lesions, and trabecular coarsening

  20. Measurements of national radiation exposure rates on train lines in Tokai area

    International Nuclear Information System (INIS)

    Matsuda, Hideharu

    1996-01-01

    For data accumulation of natural radiation exposure rate derived from gamma-ray and cosmic-ray to evaluate population dose, the author measured the rate in the running vehicles of 12 JR Tokai lines, 17 Nagoya Railway lines, 4 Kinkinippon Railway lines and 1 line of Nagoya City Bus. A portable gamma spectrometer equipped with 3' in diameter x 3' NaI (Tl) scintillation detector was placed on the seat of the vehicle for measurement in the period of December, 1992-August, 1995. Gamma-ray and cosmic-ray exposure rates in air were assessed separately as reported before and expressed in Gy/h. The average exposure rate of gamma-ray in JR Tokai lines was 19.8 nGy/h and of cosmic-ray, 28.5 nGy/h, both of which were markedly varied from line to line. The average rates of gamma-and cosmic-ray were 21.6 nGy/h and 29.0 nGy/h, respectively, in Nagoya Railway lines and 20.9 nGy/h and 28.7 nGy/h, respectively, in Kinkinippon lines. In the city bus, the respective rates were 27.2 nGy/h and 27.0 nGy/h. Thus, the average rates of gamma-ray (about 20 nGy/h) and cosmic-ray (about 29 nGy/h) were not so different between JR and other private railway lines. In the bus, the former rate was slightly lower and the latter, slightly higher. However, the total rates of both rays were in the range of about 50-55 nGy/h in all vehicles examined. (H.O.)

  1. Radiation-induced polymerization of water-saturated styrene in a wide range of dose rate

    International Nuclear Information System (INIS)

    Takezaki, J.; Okada, T.; Sakurada, I.

    1978-01-01

    Radiation-induced polymerization of water-saturated styrene (water content 3.5 x 10 -2 mole/liter) was carried out in a wide range of dose rate between 1.2 x 10 3 and 1.8 x 10 7 rad/sec, and compared with the polymerization of the moderately dried styrene (water content 3.2 x 10 -3 mole/liter). Molecular weight distribution curves of the polymerization products showed that they were generally consisted of four parts, namely, oligomers, radical, cationic, and super polymers. Contributions of the four constituents to the polymerization and the number average degrees of polymerization (DP) of the four kinds of polymers were calculated by the graphical analysis of the curves. The rate of radical polymerization and DP of radical polymers are independent of the water content; the dose rate dependences of the polymerization rate and DP agree with the well known square root and inverse square root laws, respectively, of the radical polymerization of styrene. The rate of ionic polymerization is directly proportional to the dose rate, but it decreases, at a given dose rate, inversely proportional to the water content of styrene. DP of ionic polymer is independent of the dose rate but decreases with increasing water content. The super polymer of DP about 10 4 is not formed in the case of the moderately dried styrene. G values for the initiating radical and ion formation are calculated to be independently of the dose rate and water content, 0.66 and 0.027, respectively. It was suggested that oligomer was formed in the early stage by the interaction of cation with anion and only those cations which had survived underwent polymerization. 10 figures, 4 tables

  2. Going to extremes: contrasting rates of diversification in a recent radiation of new world passerine birds.

    Science.gov (United States)

    Barker, F Keith; Burns, Kevin J; Klicka, John; Lanyon, Scott M; Lovette, Irby J

    2013-03-01

    Recent analyses suggest that a few major shifts in diversification rate may be enough to explain most of the disparity in diversity among vertebrate lineages. At least one significant increase in diversification rate appears to have occurred within the birds; however, several nested lineages within birds have been identified as hyperdiverse by different studies. A clade containing the finches and relatives (within the avian order Passeriformes), including a large radiation endemic to the New World that comprises ~8% of all bird species, may be the true driver of this rate increase. Understanding the patterns and processes of diversification of this diverse lineage may go a long way toward explaining the apparently rapid diversification rates of both passerines and of birds as a whole. We present the first multilocus phylogenetic analyses of this endemic New World radiation of finch relatives that include sampling of all recognized genera, a relaxed molecular clock analysis of its divergence history, and an analysis of its broad-scale diversification patterns. These analyses recovered 5 major lineages traditionally recognized as avian families, but identified an additional 10 relatively ancient lineages worthy of recognition at the family level. Time-calibrated diversification analyses suggested that at least 3 of the 15 family-level lineages were significantly species poor given the entire group's background diversification rate, whereas at least one-the tanagers of family Thraupidae-appeared significantly more diverse. Lack of an age-diversity relationship within this clade suggests that, due to rapid initial speciation, it may have experienced density-dependent ecological limits on its overall diversity.

  3. Assessment of absorbed dose rate from terrestrial gamma radiation in Red Sea State

    International Nuclear Information System (INIS)

    Abdalrahman, H. E. K.

    2012-09-01

    This study is primarily conducted to contribute in the overall strategic objective of producing Sudan radiation map which will include natural radiation levels and the resultant absorbed dose rate in air. The part covered by this study is the Red Sea State. Soil samples were collected from locations lie between latitudes 17.03 ° and the 20.18 ° N and longitudes 36.06 ° E during September 2007. Activity concentrations of the primordial radionuclides, 226 Ra, 232 Th, and 40 K in the samples were measured using gamma-ray spectrometry equipped with Nal (Tl) detector. Absorbed dose rates in air a height of 1 from the ground level and the corresponding annual effective doses were calculated from the measured activities using Dose Rate Conversion Factors (DRCFs). On the average, the activity concentrations were 19.22±13.13 Bq kg -1 ( 232 Th), 17.91±15.44 Bq kg -1 ( 226 Ra) and (507.13±161.67) Bq kg -1 for 40 K. The obtained results were found to be within the global values reported in the UNSCEAR publication for normal background areas with the exception of the samples taken from Arbaat area. The absorbed dose rate in air as calculated using UNSCEAR conversion factor averaged 40.93 n Gy h -1 which corresponds to annual effective dose of 50.23 μSvy -1 . The major contribution to the total absorbed dose rate comes from 40 K, which amounts to 53.36%. Using Geographical Information System (GIS), predication maps for activity concentrations levels of the measured radionuclides in the Red Sea state was prepared to show their respective spatial distributions. Similarly, GIS predictive map was produced for annual effective dose.(Author)

  4. Rate and duration of seed filling and yield of soybean affected by water and radiation deficits

    Directory of Open Access Journals (Sweden)

    Kazem GHASSEMI-GOLEZANI

    2015-11-01

    Full Text Available Seed filling and yield of soybean under water and radiation deficits were investigated during 2011 and 2012. Treatments were irrigations (I1, I2, I3 and I4 for irrigation after 60, 90, 120 and 150 mm evaporation from class A pan, respectively in main plots and light interceptions (L1: 100 %, L2: 65 % and L3: 25 % sunlight in sub-plots. Seeds per plant under I1 and I2 decreased, but under I3 and I4 increasedas a result of radiation deficit. Maximum seed weight and seed filling duration of plants under 25 % light interception (L3 were higher than those under full sunlight (L1 and 65 % light interception (L2. In contrast, plants under full sunlight had the highest seed filling rate, particularly under water stress. Seed filling duration under severe light deficit (L3 was about 9 days longer than that under full sunlight (L1, leading to 15.8 % enhancement in maximum seed weight. Decreasing seed yield of soybean under well watering and mild water stress and improving it under moderate and severe water deficit due to low solar radiation are directly related with changes in seed filling duration and consequently in seed weight and number of seeds per plant under these conditions.

  5. Analysis and modeling of dry matter production rate by soybean [Glycine max] community: Curvilinear response to radiation intensity

    International Nuclear Information System (INIS)

    Sameshima, R.

    1996-01-01

    The linear relationship between the amount of absorbed radiation and dry matter production by crop communities has long been known, and the proportionality constant between them is known as the radiation use efficiency (RUE). To analyze and predict crop production using RUE, the assumption is often made that RUE is not sensitive to radiation intensity and that dry matter production rate (DMPR) is a linear function of radiation intensity.However, there is evidence in opposition to this assumption, including reports of increasing RUE in shade tests, and hyperbolic response of photosynthetic rate to radiation intensity. The following model was developed and used to analyze the response of DMPR and RUE to daily radiation R S : DMPR = DMPR max (R S ) * g(α) where DMPR max (R S ) is the DMPR of a hypothetical soybean community absorbing all radiation, and g(α) represents the effect of radiation absorptivity (α). A hyperbolic curve and a straight line were employed for DMPR max (R S ) and g(α), respectively. Field experimental data including shade tests were used to determine the parameters for the model. Two sets of parameters were required to cover the entire experimental period. DMPR max (R S ) had an apparent curvilinear relationship with R S . The model successfully described dry matter production under successive low radiation conditions, which could not be estimated by a model with RUE insensitive to radiation. (author)

  6. Impact of uncertainties in inorganic chemical rate constants on tropospheric composition and ozone radiative forcing

    Directory of Open Access Journals (Sweden)

    B. Newsome

    2017-12-01

    regions such as the tropics, poles and upper troposphere are most uncertain. This chemical uncertainty is sufficiently large to suggest that rate constant uncertainty should be considered alongside other processes when model results disagree with measurement. Calculations for the pre-industrial simulation allow a tropospheric ozone radiative forcing to be calculated of 0.412 ± 0.062 W m−2. This uncertainty (13 % is comparable to the inter-model spread in ozone radiative forcing found in previous model–model intercomparison studies where the rate constants used in the models are all identical or very similar. Thus, the uncertainty of tropospheric ozone radiative forcing should expanded to include this additional source of uncertainty. These rate constant uncertainties are significant and suggest that refinement of supposedly well-known chemical rate constants should be considered alongside other improvements to enhance our understanding of atmospheric processes.

  7. Intraluminal Administration of Poly I:C Causes an Enteropathy That Is Exacerbated by Administration of Oral Dietary Antigen

    Science.gov (United States)

    Araya, Romina E.; Jury, Jennifer; Bondar, Constanza

    2014-01-01

    Systemic administration of polyinosinic:polycytidylic acid (poly I:C), mimics virally-induced activation of TLR3 signalling causing acute small intestine damage, but whether and how mucosal administration of poly I:C causes enteropathy is less clear. Our aim was to investigate the inflammatory pathways elicited after intraluminal administration of poly I:C and determine acute and delayed consequences of this locally induced immune activation. Intraluminal poly I:C induced rapid mucosal immune activation in C57BL/6 mice involving IFNβ and the CXCL10/CXCR3 axis, that may drive inflammation towards a Th1 profile. Intraluminal poly I:C also caused enteropathy and gut dysfunction in gliadin-sensitive NOD-DQ8 mice, and this was prolonged by concomitant oral administration of gliadin. Our results indicate that small intestine pathology can be induced in mice by intraluminal administration of poly I:C and that this is exacerbated by subsequent oral delivery of a relevant dietary antigen. PMID:24915573

  8. The effect of sampling rate on interpretation of the temporal characteristics of radiative and convective heating in wildland flames

    Science.gov (United States)

    David Frankman; Brent W. Webb; Bret W. Butler; Daniel Jimenez; Michael Harrington

    2012-01-01

    Time-resolved radiative and convective heating measurements were collected on a prescribed burn in coniferous fuels at a sampling frequency of 500 Hz. Evaluation of the data in the time and frequency domain indicate that this sampling rate was sufficient to capture the temporal fluctuations of radiative and convective heating. The convective heating signal contained...

  9. SSDL quality assurance for environmental dose/dose rate monitoring of photon radiation

    International Nuclear Information System (INIS)

    1987-01-01

    Member states of IAEA have recently approved an expanded Nuclear Safety Programme and two International Conventions have been signed. One concerns early notification of a nuclear accident, and the other concerns assistance in the case of a nuclear accident or radiological emergency. In the course of the implementation of these conventions an international system will be established by the Agency for the reception and dissemination of data following a nuclear accident. Such data should include the results of radiation measurements obtained by radiation monitoring. These data must be reliable, and comparable. This assures that numerical values of measured quantities obtained at different times, sites and countries, and with different instruments, can be compared in order that the competent authorities may draw conclusions. Such measurements may also have legal consequences. This implies that the instruments used for the measurement should comply with the relevant international specifications, and that the readings of these instruments be traceable to the international measurement system. At a meeting of an expert working group on International Cooperation in Nuclear Safety and Radiation Protection held in November 1986, a proposal to produce a technical document on ''The role of SSDLs in the quality assurance programme relating to the use of dose and dose rate meters for personal and environmental measurements'' received high priority, and at a subsequent meeting of the Board of Governors the proposal was approved. Prior to these proposals the SSDL Scientific Committee at its annual meeting in May 1986 also advised the IAEA to promote measures to ensure world wide reliability and traceability of dose measurements in the field of radiation protection. On 26-30 January 1987 an Advisory Group Meeting on ''The role of SSDLs in the dosimetry of unintentional radiation exposures'' was organized by the IAEA. This Advisory Group assisted the Agency in the formulation of a

  10. Incident solar radiation and coronary heart disease mortality rates in Europe

    International Nuclear Information System (INIS)

    Wong, Alfred

    2008-01-01

    The reported low mortality rate from coronary heart disease in Portugal, Spain, Italy, Greece, and France, to a lesser extent, has been attributed in numerous nutritional studies to the consumption of a Mediterranean-type diet. There are still many unresolved issues about the direct causal effect of the Mediterranean dietary regime on low incidence of coronary heart disease. An analysis of coronary heart disease mortality rates in Europe from a latitudinal gradient perspective has shown to have a close correlation to incident solar radiation. It is surmised that the resulting increased in situ biosynthesis of Vitamin D 3 could be the critical missing confounder in the analysis of the beneficial health outcome of the Mediterranean diet

  11. Relationship between increased radiation dose rate in air and rainfall, 3

    International Nuclear Information System (INIS)

    Suzuki, Osamu

    1985-01-01

    The influence of snow on dose rate in air (DRA) was analyzed. Attenuatin ratio of DRA due to snow depends on the amount of water per surface area. When snow reaches one m, DRA does not seem to be influenced by radioactivity from the ground, but seems to be only influenced by natural radioactivity of buildings. A method was examined to estimate background radiation doses during the snow season with counting rates of peak areas of 1.765 MeV for Bi-214 and 2.614 MeV for Tl-208. In serial measurements of environmental gamma rays, the method of measuring spectra is far superior to other methods in view of the collection of much more information. (Namekawa, K.)

  12. Modelling radiation exposure in homes from siporex blocks by using exhalation rates of radon

    Directory of Open Access Journals (Sweden)

    Nikolić Mladen D.

    2015-01-01

    Full Text Available Building materials are the second major source of indoor radon, after soil. The contribution of building materials to indoor radon amount depends upon the radium content and exhalation rates, which can be used as a primary index for radon levels in the dwellings. This paper presents the results of using the experimentally determined exhalation rates of siporex blocks and concrete plates, to assess the radiation exposure in dwellings built of siporex blocks. The annual doses in rooms have been estimated depending on the established modes of ventilation. Realistic scenario was created to predict an annual effective dose for an old person, a housewife, a student, and an employed tenant, who live in the same apartment, spending different periods of time in it. The results indicate the crucial importance of good ventilation of the living space.

  13. Effect of prolonged irradiation by low dose-rate ionizing radiation on the hemopoiesis of mice

    Energy Technology Data Exchange (ETDEWEB)

    Yanai, Takanori; Shirata, Katsutoshi; Saitou, Mikio; Tanaka, Satoshi; Onodera, Junichi; Otsu, Hiroshi; Sato, Fumiaki [Institute for Environmental Sciences, Department of Radiobiology, Rokkasho, Aomori (Japan)

    1999-07-01

    To evaluate effects of prolonged irradiation by low dose-rate ionizing radiation on the hemopoiesis of mice, SPF C3H/HeN female mice were irradiated by {sup 137}Cs {gamma}-rays with doses of 1-8 Gy at the dose rate of 20 mGy (22 h-day){sup -1}. After irradiation, the number of hemopoietic cells contained in bone marrow was determined by the methods of CFU-S and CFU-GM assay, and the number of peripheral blood cells was counted. It was shown that the day 12-CFU-S, which is in the earlier stage of differentiation, decreased as the dose increased. Decreases of the numbers of day 7-CFU-S and CFU-GM were also observed. However, there were no remarkable changes in the number of peripheral blood cells. (author)

  14. Effect of prolonged irradiation by low dose-rate ionizing radiation on the hemopoiesis of mice

    Energy Technology Data Exchange (ETDEWEB)

    Yanai, Takanori; Shirata, Katsutoshi; Yamada, Yutaka; Saitou, Mikio; Izumi, Jun; Tanaka, Satoshi; Otsu, Hiroshi; Sato, Fumiaki [Institute for Environmental Sciences, Rokkasho, Aomori (Japan)

    2000-07-01

    For evaluation of effects of prolonged irradiation by low dose-rate ionizing radiation on the hemopoiesis of mice, SPF C3H/HeN female mice were irradiated with {sup 137}Cs {gamma}-rays with doses of 1-4 Gy at the dose rate of 20 mGy/22h-day. After irradiation, the number of hemopoietic cells contained in spleen was determined by the methods of CFU-S and CFU-GM assay, and the number of peripheral blood cells was counted. It was shown that the number of CFU-S colonies on day 12, which is in the earlier stage of differentiation, decreased as dose increased. No remarkable changes in the number of peripheral blood cells, however, were observed. (author)

  15. Integrated High-Rate Transition Radiation Detector and Tracking Chamber for the LHC

    CERN Multimedia

    2002-01-01

    % RD-6 \\\\ \\\\Over the past five years, RD-6 has developed a transition radiation detector and charged particle tracker for high rate operation at LHC. The detector elements are based on C-fibre reinforced kapton straw tubes of 4~mm diameter filled with a Xenon gas mixture. Detailed measurements with and without magnetic field have been performed in test beams, and in particular have demonstrated the possibility of operating straw tubes at very high rate (up to 20~MHz) with accurate drift-time measurement accuracy. A full-scale engineering prototype containing 10~000 straws is presently under assembly and will be accurately measured with a powerful X-ray tube. Integrated front-end electronics with fast readout have been designed and successfully operated in test beam. \\\\ \\\\Finally extensive simulations performed for ATLAS have shown that such a detector will provide powerful pattern recognition, accurate momentum measurements, efficient level-2 triggering and excellent electron identification, even at the highe...

  16. ESR dating of elephant teeth and radiation dose rate estimation in soil

    International Nuclear Information System (INIS)

    Taisoo Chong; Ohta, Hiroyuki; Nakashima, Yoshiyuki; Iida, Takao; Saisho, Hideo

    1989-01-01

    Chemical analysis of 238 U, 232 Th and 40 K in the dentine as well as enamel of elephant tooth fossil has been carried out in order to estimate the internal absorbed dose rate of the specimens, which was estimated to be (39±4) mrad/y on the assumption of early uptake model of radionuclides. The external radiation dose rate in the soil including the contribution from cosmic rays was also estimated to be (175±18) mrad/y with the help of γ-ray spectroscopic techniques of the soil samples in which the specimens were buried. The 60 Co γ-ray equivalent accumulated dose of (2±0.2) x 10 4 rad for the tooth enamel gave ''ESR age'' of (9±2) x 10 4 y, which falls in the geologically estimated range between 3 x 10 4 and 30 x 10 4 y before the present. (author)

  17. Gamma Low-Dose-Rate Ionizing Radiation Stimulates Adaptive Functional and Molecular Response in Human Aortic Endothelial Cells in a Threshold-, Dose-, and Dose Rate-Dependent Manner.

    Science.gov (United States)

    Vieira Dias, Juliana; Gloaguen, Celine; Kereselidze, Dimitri; Manens, Line; Tack, Karine; Ebrahimian, Teni G

    2018-01-01

    A central question in radiation protection research is whether low-dose and low-dose-rate (LDR) exposures to ionizing radiation play a role in progression of cardiovascular disease. The response of endothelial cells to different LDR exposures may help estimate risk of cardiovascular disease by providing the biological mechanism involved. We investigated the effect of chronic LDR radiation on functional and molecular responses of human aorta endothelial cells (HAoECs). Human aorta endothelial cells were continuously irradiated at LDR (6 mGy/h) for 15 days and analyzed at time points when the cumulative dose reached 0.05, 0.5, 1.0, and 2.0 Gy. The same doses were administered acutely at high-dose rate (HDR; 1 Gy/min). The threshold for the loss of angiogenic capacity for both LDR and HDR radiations was between 0.5 and 1.0 Gy. At 2.0 Gy, angiogenic capacity returned to normal only for HAoEC exposed to LDR radiation, associated with increased expression of antioxidant and anti-inflammatory genes. Pre-LDR, but not pre-HDR, radiation, followed by a single acute 2.0 Gy challenge dose sustained the expression of antioxidant and anti-inflammatory genes and stimulated angiogenesis. Our results suggest that dose rate is important in cellular response and that a radioadaptive response is involved for a 2.0 Gy dose at LDR.

  18. Energy levels, radiative rates, and lifetimes for transitions in W XL

    International Nuclear Information System (INIS)

    Aggarwal, Kanti M.; Keenan, Francis P.

    2014-01-01

    Energy levels and radiative rates are reported for transitions in Br-like tungsten, W XL, calculated with the general-purpose relativistic atomic structure package (GRASP). Configuration interaction (CI) has been included among 46 configurations (generating 4215 levels) over a wide energy range up to 213 Ryd. However, for conciseness results are only listed for the lowest 360 levels (with energies up to ∼43 Ryd), which mainly belong to the 4s 2 4p 5 ,4s 2 4p 4 4d,4s 2 4p 4 4f,4s4p 6 ,4p 6 4d,4s4p 5 4d,4s 2 4p 3 4d 2 , and 4s 2 4p 3 4d4f configurations, and provided for four types of transitions, E1, E2, M1, and M2. Comparisons are made with existing (but limited) results. However, to fully assess the accuracy of our data, analogous calculations have been performed with the flexible atomic code, including an even larger CI than in GRASP. Our energy levels are estimated to be accurate to better than 0.02 Ryd, whereas results for radiative rates (and lifetimes) should be accurate to better than 20% for a majority of the strong transitions

  19. Radiation in relation to mutation rate, mutational damage and human ill-health

    International Nuclear Information System (INIS)

    Roberts, P.B.

    1976-09-01

    The effect of radiation in increasing the frequency of gene mutations is now reasonably understood. We discuss first how an increase in the mutation rate is reflected in the mutational damage expressed in populations. It is shown that the mutational damage, assessed by the loss of fitness in a population or the number of eventual gene extinctions, is equal to the number of new mutations arising per generation or the mutation rate. In a population of stable size, a dose of 1 rem given to 10 6 people leads to roughly 600 gene extinctions when summed over all ensuing generations if the dose is applied to only one generation; this number of extinctions will occur in each succeeding generation if the dose is given to every generation. However, the concept of genetic extinction, although quantifiable, is of limited value in assessing radiation risks since its impact on human ill-health is very speculative. In particular, no estimate can be made of the total cost of effects which are minor in each individual in which they arise, but which, because they are so minor, persist in the population for many generations. The best current estimate is for 14-140 obvious defects in the first few generations following exposure of 10 6 people to a dose of 1 rem. (auth.)

  20. Anomalous resonance-radiation energy-transfer rate in a scattering dispersive medium

    International Nuclear Information System (INIS)

    Shekhtman, V.L.

    1992-01-01

    This paper describes a generalization of the concept of group velocity as an energy-transfer rate in a dispersive medium with complex refractive index when the polaritons, which are energy carriers, undergo scattering, in contrast to the classical concept of the group velocity of free polaritons (i.e., without scattering in the medium). The concept of delay time from quantum multichannel-scattering, theory is used as the fundamental concept. Based on Maxwell's equations and the new mathematical Φ-function method, a consistent conceptual definition of group velocity in terms of the ratio of the coherent-energy flux density to the coherent-energy density is obtained for the first time, and a critical analysis of the earlier (Brillouin) understanding of energy-transfer rate is given in the light of radiation-trapping theory and the quantum theory of resonance scattering. The role of generalized group velocity is examined for the interpretation of the phenomenon of multiple resonance scattering, or radiation diffusion. The question of causality for the given problem is touched upon; a new relationship is obtained, called the microcausality condition, which limits the anomalous values of group velocity by way of the indeterminacy principle and the relativistic causality principle for macroscopic time intervals directly measurable in experiment, whereby attention is focused on the connection of the given microcausality condition and the well-known Wigner inequality for the time delay of spherical waves. 22 refs

  1. Low rate doses effects of gamma radiation on glycoproteins of transmembrane junctions in fibroblasts

    International Nuclear Information System (INIS)

    Bringas, J.E.; Caceres, J.L.

    1996-01-01

    Glycoproteins of trans-membrane junctions are molecules that help to bind cells with the extracellular matrix. Integrins are the most important trans-membrane molecules among others. The damage of gamma radiation on those proteins could be an important early event that causes membrane abnormalities which may lead to cell malfunction and cancer induced by radiation due to cell dissociation. Randomized blocks with 3 repetitions of mouse embryo fibroblast cultures, were irradiated with Cobalt-60 gamma rays, during 20 days. Biological damage to glycoproteins and integrins was evaluated by cellular growth and fibroblast proliferative capacity. Integrins damage was studied by isolation by column immunoaffinity chromatography migrated on SDS-Page under reducing and non reducing conditions, and inhibition of integrins extracellular matrix adhesion by monoclonal antibodies effect. The dose/rate (0.05 Gy/day-0.2 Gy/day) of gamma given to cells did not show damage evidence on glycoproteins and integrins. If damage happened, it was repaired by cells very soon, was delayed by continuous cellular division or by glycoproteins characteristic of being multiple extracellular ligatures. Bio effects became more evident with an irradiation time greater than 20 days or a high dose/rate. (authors). 6 refs

  2. Enhancement of deposition rate at cryogenic temperature in synchrotron radiation excited deposition of silicon film

    International Nuclear Information System (INIS)

    Nara, Yasuo; Sugita, Yoshihiro; Ito, Takashi; Kato, Hiroo; Tanaka, Ken-ichiro

    1989-01-01

    The authors have investigated the synchrotron radiation excited deposition of silicon films on the SiO 2 substrate by using SiH 4 /He mixture gas at BL-12C at Photon Factory. They used VUV light from the multilayer mirror with the center photon energy from 97 to 123eV, which effectively excites L-core electrons of silicon. Substrate temperature was widely varied from -178 degree C to 500 degree C. At -178 degree C, the deposition rate was as high as 400nm/200mAHr (normalized at the storage ring current at 200mA). As increasing the substrate temperature, the deposition rate was drastically decreased. The number of deposited silicon atoms is estimated to be 4 to 50% of incident photons, while the number of photo generated species in the gas phase within the mean free path from the surface is calculated as few as about 10 -3 of incident photons. These experimental results show that the deposition reaction is governed by the dissociation of surface adsorbates by the synchrotron radiation

  3. Parametrization of the average ionization and radiative cooling rates of carbon plasmas in a wide range of density and temperature

    OpenAIRE

    Gil de la Fe, Juan Miguel; Rodriguez Perez, Rafael; Florido, Ricardo; Garcia Rubiano, Jesus; Mendoza, M.A.; Nuez, A. de la; Espinosa, G.; Martel Escobar, Carlos; Mínguez Torres, Emilio

    2013-01-01

    In this work we present an analysis of the influence of the thermodynamic regime on the monochromatic emissivity, the radiative power loss and the radiative cooling rate for optically thin carbon plasmas over a wide range of electron temperature and density assuming steady state situations. Furthermore, we propose analytical expressions depending on the electron density and temperature for the average ionization and cooling rate based on polynomial fittings which are valid for the whole range...

  4. Balloon expandable intraluminal grafting of normal and abnormal renal arteries: Experimental study

    International Nuclear Information System (INIS)

    Palmaz, J.C.; Hayashi, H.; Schatz, R.; Hunter, G.; Tio, F.O.; Garcia, O.

    1986-01-01

    Balloon expandable intraluminal grafts were placed in renal arteries of eight adult dogs and 11 minipigs. The renal arteries were normal in the dogs before graft placement. Two grafts were placed in primary division branches and the rest in the main renal artery. Experimental renal artery stenosis was created in the minipigs by subocclusive ligature of the renal artery with absorbable suture material. Six months later significant renal artery stenoses developed in six pigs and were corrected by graft placement. In the remaining pigs grafts were placed in the opposite normal renal artery because the stenosis caused a small, shrunken kidney in two, and severe spasm or anatomic variations prevented graft placement in three. All grafts remained patent on angiographic and pathologic examinations to a maximum follow-up to 24 weeks

  5. Iron-Deficiency Anemia Leading to Transient Ischemic Attacks due to Intraluminal Carotid Artery Thrombus

    Directory of Open Access Journals (Sweden)

    H. Z. Batur Caglayan

    2013-01-01

    Full Text Available Reactive thrombocytosis secondary to iron-deficiency anemia (IDA is a rare but recognized cause of stroke. We report the case of a patient with iron-deficiency anemia presenting with multiple transient ischemic attacks (TIA due to intraluminal thrombus of an internal carotid artery. The putative mechanisms underlying anemia and stroke syndromes are not completely understood, and it is believed that iron deficiency may cause ischemic stroke by several potential mechanisms. Thrombocytosis is often associated with iron deficiency, and microcytosis produces a reduction in the red cell deformability and could produce a hypercoagulable state. The platelet count and function observed in iron-deficiency anemia could act synergistically to promote thrombus formation, especially in the setting of an underlying atherosclerotic disease. The presence of floating thrombus in a patient with clinical and MRI evidence of stroke represents a significant therapeutic dilemma and requires immediate decision about treatment.

  6. Abdominal aortic aneurysm, arterial stiffening and the role of the intraluminal thrombus

    DEFF Research Database (Denmark)

    Lyck Hansen, Maria; Dahl Thomsen, Marie; Melholt Rasmussen, Lars

    2015-01-01

    PATIENTS AND METHODS: PWV and PWA were measured in male patients with AAA from an ongoing Danish AAA screening trial. Information on blood pressure, medications, BMI and smoking status was obtained at inclusion. RESULTS: In total, 157 patients were included. Mean age was 73 years. Mean AAA size...... was 42.2 mm. Fifty-six of the patients had an intraluminal thrombus, and patients with AAA and ILT had a significantly higher Aix75 than patients with AAA but without ILT (Mean = 28.3 ± 1.4 SEM vs. 24.9 ± 0.81, p=0.027), a difference that was also significant when adjusting for AAA size, blood pressure...... and age. There was no difference in PWV between the groups. CONCLUSIONS: Haemodynamic properties of the aorta are affected by the presence of ILT in patients with AAA that is not explained by aortic size. Alternatively, these findings could be explained by associations between ILT and properties...

  7. Exposure rate measurements and radiation control in post therapy with I131

    International Nuclear Information System (INIS)

    Vazquez A, M.; Castillo D, C.; Flores U, H.; Cespedes C, L.; Morgan N, C.; Sifuentes D, Y.; Marin R, K.

    2015-10-01

    During hyperthyroidism treatment, 131 I activities from 111 MBq up to 296 MBq are used. In the aim to determine if the 131 I uptake by the patient is a radiological risk to family members and public around the patient exposure rate measurements were carried out, using a limit 1.8 m R/h. Measurements were carried out in the Nuclear Medicine department of Almenara hospital in Lima, Peru. The exposure rate was measured to 0.3, 0.6, and 1.0 m from the patient from 0 to 11 days after post-administrated dose (Pda). In this study measurements were carried out in 21 hyperthyroid patients. Measurements to 1 meter, along 2-4 (16/16), 5-7 (15/15), and 8-11 (14/14) days after Pda, indicate the dose rate around 100% of patients is ≤ 1.8 m R /h. Measurements to 0.6 meters along 2-4 (16/16), 5 -7 (15/15), and 8-11 (14/14) days after Pda, indicate that the dose rate around 44% (7/16), 93% (14/15), and 100% (14/14) of patients is ≤ 1.8 m R h. On the other hand, dose rate measurements to 0.3 meters, along 2-4 (16/16), 5-7 (15/15), and 8 -11 (14/14) days after Pda, indicate that de dose rate is 13% (2/16), 6% (1/15), and 43% (6/14) of patients is ≤ 1.8 m R/h. Measured exposure rates are alike to values reported in the literature, and were used to define radiation control recommendations. (Author)

  8. Treatment of esophageal tumors using high intensity intraluminal ultrasound: first clinical results

    Directory of Open Access Journals (Sweden)

    Prat Frederic

    2008-06-01

    Full Text Available Abstract Background Esophageal tumors generally bear a poor prognosis. Radical surgery is generally the only curative method available but is not feasible in the majority of patients; palliative therapy with stent placement is generally performed. It has been demonstrated that High Intensity Ultrasound can induce rapid, complete and well-defined coagulation necrosis. Thus, for the treatment of esophageal tumors, we have designed an ultrasound applicator that uses an intraluminal approach to fill up this therapeutic gap. Methods Thermal ablation is performed with water-cooled ultrasound transducers operating at a frequency of 10 MHz. Single lesions extend from the transducer surface up to 10 mm in depth when applying an intensity of 14 W/cm2 for 10s. A lumen inside the therapy applicator provides path for an endoscopic ultrasound imaging probe operating at a frequency of 12 MHz. The mechanical rotation of the applicator around its axis enables treatment of sectorial or cylindrical volumes. This method is thus particularly suitable for esophageal tumors that may develop only on a portion of the esophageal circumference. Previous experiments were conducted from bench to in vivo studies on pig esophagi. Results Here we report clinical results obtained on four patients included in a pilot study. The treatment of esophageal tumors was performed under fluoroscopic guidance and ultrasound imaging. Objective tumor response was obtained in all cases and a complete necrosis of a tumor was obtained in one case. All patients recovered uneventfully and dysphagia improved significantly within 15 days, allowing for resuming a solid diet in three cases. Conclusion This clinical work demonstrated the efficacy of intraluminal high intensity ultrasound therapy for local tumor destruction in the esophagus.

  9. Manufacture research of the test equipment to measure the dose rate in high radiation medium

    International Nuclear Information System (INIS)

    Phan Luong Tuan; Nguyen Van Sy; Nguyen Xuan Vinh; Dang Quang Bao; Nguyen Thanh Hung; Pham Minh Duc; Nguyen Xuan Truong

    2017-01-01

    Photodiode BPW34 is operated as a low voltage counter tubes. When the radiation rays go into the BPW34,they will create a pairs of electron and hole. If setting the reverse bias in to the BPW34, a pulse is achieved and it can be amplified and processed. The STM32 is the microcontroller family which is developed base on ARM processors. The STM32 incorporated many new features such as ADC, I2C, etc. With the connectional ability to other devices, the STM32 is proving its advantages in the development of equipment.The application of irradiation technology in the economy-society increases widespread as food irradiation, mutant irradiation, etc. Until now the calculation the high dose rate at Hanoi Irradiation Center is identified by the Fricke, ECB dosimeters. The dosimeters must be destroyed in order to serve for dose rate determination. Manufacture research the equipment for dose rate calculation support to determine dose rate directly through the equipment’s signal and this equipment can be used multiple. This equipment can be connected to other devices to control the irradiation process better via signals. (author)

  10. 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

  11. Interannual Variability in Dust Deposition, Radiative Forcing, and Snowmelt Rates in the Colorado River Basin

    Science.gov (United States)

    Skiles, M.; Painter, T. H.; Deems, J. S.; Barrett, A. P.

    2011-12-01

    Dust in snow accelerates snowmelt through its direct reduction of albedo and its further reduction of albedo by accelerating the growth of snow effective grain size. Since the Anglo expansion and disturbance of the western US that began in the mid 19th century, the mountain snow cover of the Colorado River Basin has been subject to five-fold greater dust loading. Here we present the impacts of dust deposition onto alpine snow cover using a 7-year energy balance record at the alpine and subalpine towers in the Senator Beck Basin Study Area (SBBSA), San Juan Mountains in southwestern Colorado, USA. We assess the radiative and hydrologic impacts with a two-layer point snow energy balance snowmelt model that calculates snowmelt and predicts point runoff using measured inputs of energy exchanges and snow properties. By removing the radiative forcing due to dust, we can determine snowmelt under observed dusty and modeled clean conditions. Additionally, we model the relative response of melt rates to simulated increases in air temperature. Our modeling results indicate that the number of days that dust advances retreat of snow cover and cumulative radiative forcing are linearly related to total dust concentration. The greatest dust radiative impact occurred in 2009, when the highest observed end of year dust concentrations reduced visible albedo to less than 0.35 during the last three weeks of snowcover and snow cover duration was shortened by 50 days. This work also shows that dust radiative forcing has a markedly greater impact on snow cover duration than increases in temperature in terms of acceleration of snowmelt. We have completed the same analysis over a 2-year energy balance record at the Grand Mesa Study plot (GMSP) in west central Colorado, 150 km north of SBBSA. This new location allows us to assess site variability. For example, at SBBSA 2010 and 2011 were the second and third highest dust deposition years, respectively, but 2010 was a larger year with 3

  12. Direct stent puncture technique for intraluminal stent recanalization in the superficial femoral and popliteal arteries in-stent occlusion: Outcomes from a prospective clinical analysis of diabetics with critical limb ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Palena, Luis Mariano, E-mail: marianopalena@hotmail.com; Manzi, Marco

    2013-07-15

    Purpose: To evaluate the efficacy and safety of “Direct Stent Puncture” technique for intraluminal stent recanalization in the femoro-popliteal segments. Methods and Materials: A cohort of diabetics who had symptomatic in-stent occlusion of the superficial femoral or popliteal arteries underwent endovascular recanalization. After antegrade failure, direct stent puncture technique was performed. The primary end-point was to efficacy assessment, intended as technical success and clinical improvement. The secondary end-point was safety assessment, intended as free of complication rate. Results: Fifty-four patients (37 men; 73.6 ± 8.5 years) underwent direct stent puncture technique, after several unsuccessful antegrade attempts to cross the occluded stent. Technical success for intraluminal stent recanalization was achieved in 53/54 (98.2%) of cases and failed in 1/54 (1.8%). Clinical improvement was obtained in 51/54 (94.4%) of cases, with regression of the clinical symptoms and improvement of the TcPO{sub 2}, from 3 ± 18 mmHg to 43 ± 11 mmHg after 15 days (p < 0.001). Free of complications rate was 92.5%. In 2/54 (3.7%) of cases distal embolization occurred, in 1/54 (1.9%) case a sudden vessel thrombosis was diagnosed after 12 hours and in 1/54 (1.9%) case hematoma at the stent puncture site was observed. Conclusions: Direct Stent Puncture technique is an efficacy and safety option for intraluminal stent recanalization in the femoro-popliteal segment in-stent occlusion.

  13. Survival rate of patients with differentiated thyroid cancer without early postoperative external radiation of the neck

    International Nuclear Information System (INIS)

    Saur, H.B.; Lerch, H.; Schober, O.

    1996-01-01

    Results of survival rates in differentiated thyroid carcinoma and comparison with a review of literature are given. Four hundred and sixty-four patients with differentiated cancer of the thyroid (354 female, 110 male, range: 6 to 84 years, median: 46.8 years; 275 patients with papillary and 190 with follicular cancer) were analyzed retrospectively. All patients were treated with ablative doses of radioiodine after thyroidectomy including compartment oriented lymphadenectomy in 27 patients. All patients passed an individual systematic follow-up according to risk: 'Low risk' pT≤3NxM0 vs. 'high risk' pT4 and/or M1. Early postoperative radiation was not included even in patients with local invasion (pT4). The corrected 5- and 10-year survival rates for papillary cancer are 0.91 and 0.91, for follicular cancer 0.94 resp. 0.78 (p=0.55), age (≤40 years 0.96 and 0.96, >40 years 0.90 and 0.80; p=0.008), gender (female 0.93 and 0.92, male 0.90 and 0.70; p=0.06) and invasion/distant metastases (pT4 and/or M1 0.83 and 0.71, other 0.97 and 0.97; p=0.0001). A systematic follow-up with an individually adapted standardized scheme is associated with high survival rates in patients with differentiated cancer of the thyroid. Early diagnosis of recurrences, locoregional lymph node and distant metastases with early surgical treatment including compartment oriented lymphadenectomy and radioiodine therapy yield high survival even without external radiation. (orig./MG) [de

  14. Dose Response Model of Biological Reaction to Low Dose Rate Gamma Radiation

    International Nuclear Information System (INIS)

    Magae, J.; Furikawa, C.; Hoshi, Y.; Kawakami, Y.; Ogata, H.

    2004-01-01

    time, and that dose rate effect changes as a function of dose-rate and irradiation time. Many epidemiological and experimental studies have been demonstrated that biological responses to radiation at low dose/low dose rate does not follow LNT. Our study supports their observations with sufficient statistical power. Threshold of radiation risk will be discussed. (Author)

  15. Radiation

    International Nuclear Information System (INIS)

    2013-01-01

    The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

  16. Influence of radiation dose and dose-rate on modification of barley seed radiosensitivity by post-treatment with caffeine

    International Nuclear Information System (INIS)

    Sharma, G.J.

    1987-01-01

    Influence of radiation doses (100, 150 and 200 Gy) and dose-rates (1.27-0.023 Gy/Sec) on the modification of oxic and anoxic radiation damage by caffeine at different concentrations has been investigated using metabolizing barley seeds as test system. As the radiation dose increases from 100 to 200 Gy, the magnitude of oxic and anoxic damages increase at all the dose-rates. Caffeine is able to afford partial radioprotection against the oxic damage, at the same time potentiating the anoxic damage. However, caffeine effect against the oxic and anoxic components of damage depend largely upon the dose of radiation applied and also on the dose-rate used. The possible mechanism of action of caffeine in bringing about the differential modification of oxic and anoxic damages has been discussed. 19 refs., 2 tables. (author)

  17. 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

  18. Survey of the gamma dose rate and locations with extremely abnormal radiation

    International Nuclear Information System (INIS)

    Sansoni, B.; Matthes, W.

    1985-01-01

    The goals pursued by the investigation on hand were: (a) to get a survey of natural radioactivity in the Fichtelgebirge; (b) to find and describe locally restricted areas of high natural radioactivity (abnormal radiation, hot spots); this will be a starting point (c) for the assessment of possible increased radiation exposure and of the state of health of a restricted number of persons. Furthermore, there are also (d) underground data for the eventual stipulation of maximum permissible values for natural radioactivity. (e) The situation in the Fichtelgebirge shall be compared with that of the monazite sand-stone areas in India. The highest gamma dose rates measured in locally restricted areas were: (1) granite road pavement: 24 μR/h; (2) granite quarries (35 μR/h); (3) caves below granite rock (40 to 70 μR/h); (4) slag brick pavement on market place and main street of Marktredwitz (53.4 μR/h) (part of which removed already); (5) uranium abnormalities on a farmer's field (80-100 μR/h) (0.6 m below the surface: 1.500 μR/h); this may be considered a uranium deposit with a content in uranium of up to 0.3%; (6) over 100 μR/h in front of an uranium ore mine in the uranium prospection drift (rest of the drift in the granite no more than 29.3+-3.3 μR/h). The resulting maximum conceivable radiation exposure is assessed. The question whether there is a necessity for setting tolerance limit values for natural radioactivity is raised again; the magnitude in comparison with limit values for artificial radioactivity in radioactive controlled areas is pointed out. (orig./HP) [de

  19. Effects of electromagnetic radiation (bright light, extremely low-frequency magnetic fields, infrared radiation) on the circadian rhythm of melatonin synthesis, rectal temperature, and heart rate.

    Science.gov (United States)

    Griefahn, Barbara; Künemund, Christa; Blaszkewicz, Meinolf; Lerchl, Alexander; Degen, Gisela H

    2002-10-01

    Electromagnetic spectra reduce melatonin production and delay the nadirs of rectal temperature and heart rate. Seven healthy men (16-22 yrs) completed 4 permuted sessions. The control session consisted of a 24-hours bedrest at infrared radiation (65 degrees C) was applied from 5 pm to 1 am. Salivary melatonin level was determined hourly, rectal temperature and heart rate were continuously recorded. Melatonin synthesis was completely suppressed by light but resumed thereafter. The nadirs of rectal temperature and heart rate were delayed. The magnetic field had no effect. Infrared radiation elevated rectal temperature and heart rate. Only bright light affected the circadian rhythms of melatonin synthesis, rectal temperature, and heart rate, however, differently thus causing a dissociation, which might enhance the adverse effects of shiftwork in the long run.

  20. Lifetime radiation risks from low-dose rate radionuclides in beagles

    International Nuclear Information System (INIS)

    Goldman, M.; Rosenblatt, L.S.

    1985-01-01

    One of the largest, long-term (25-yr) animal studies on the effects of low-dose internal irradiation is almost completed. Some 335 beagles were given continuous exposure to graded 90 Sr [low linear energy transfer (LET)] in their diets (D-dogs) through adulthood. A second group (R-dogs) was given fractionated doses of 225 Ra (high LET) as young adults. A third group of 44 was given a single injection of 90 Sr as adults (S-dogs) to compare single to continuous dosages. All dogs were followed through their lifetimes. Only one of the 848 dogs is still alive. The animals were whole-body counted over their entire life span and were examined frequently for assessment of medical status. There were no acute radiation lethalities. Analyses of the large data base from these dogs have begun and preliminary indications are that 90 Sr, which was tested over a 1500-fold skeletal dose rate range, does not cause significant life shortening at average accumulation skeletal doses of ∼2500 rads (25 Gy) and that a curvilinear dose response curve for life shortening was seen at higher accumulation doses. The data will be discussed in terms of modern epidemiological concepts and quantifications will be related to certain parameters of human risk from acute or chronic radiation exposures

  1. The numerical evaluation on non-radiative multiphonon transition rate from different electronic bases

    International Nuclear Information System (INIS)

    Zhu Bangfen.

    1985-10-01

    A numerical calculation on the non-radiative multiphonon transition probability based on the adiabatic approximation (AA) and the static approximation (SA) has been accomplished in a model of two electronic levels coupled to one phonon mode. The numerical results indicate that the spectra based on different approximations are generally different apart from those vibrational levels which are far below the classical crossing point. For large electron-phonon coupling constant, the calculated transition rates based on AA are more reliable; on the other hand, for small transition coupling the transition rates near or beyond the cross region are quite different for two approximations. In addition to the diagonal non-adiabatic potential, the mixing and splitting of the original static potential sheets are responsible for the deviation of the transition rates based on different approximations. The relationship between the transition matrix element and the vibrational level shift, the Huang-Rhys factor, the separation of the electronic levels and the electron-phonon coupling is analysed and discussed. (author)

  2. Probing polymer crystallization at processing-relevant cooling rates with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Cavallo, Dario, E-mail: Dario.cavallo@unige.it [University of Genoa, Dept. of Chemistry and Industrial Chemistry, Via Dodecaneso 31, 16146 Genoa (Italy); Portale, Giuseppe [ESRF, Dubble CRG, Netherlands Organization of Scientific Research (NWO), 38043 Grenoble (France); Androsch, René [Martin-Luther-University Halle-Wittenberg, Center of Engineering Sciences, D-06099 Halle/S. (Germany)

    2015-12-17

    Processing of polymeric materials to produce any kind of goods, from films to complex objects, involves application of flow fields on the polymer melt, accompanied or followed by its rapid cooling. Typically, polymers solidify at cooling rates which span over a wide range, from a few to hundreds of °C/s. A novel method to probe polymer crystallization at processing-relevant cooling rates is proposed. Using a custom-built quenching device, thin polymer films are ballistically cooled from the melt at rates between approximately 10 and 200 °C/s. Thanks to highly brilliant synchrotron radiation and to state-of-the-art X-ray detectors, the crystallization process is followed in real-time, recording about 20 wide angle X-ray diffraction patterns per second while monitoring the instantaneous sample temperature. The method is applied to a series of industrially relevant polymers, such as isotactic polypropylene, its copolymers and virgin and nucleated polyamide-6. Their crystallization behaviour during rapid cooling is discussed, with particular attention to the occurrence of polymorphism, which deeply impact material’s properties.

  3. The Bayesian count rate probability distribution in measurement of ionizing radiation by use of a ratemeter

    Energy Technology Data Exchange (ETDEWEB)

    Weise, K.

    2004-06-01

    Recent metrological developments concerning measurement uncertainty, founded on Bayesian statistics, give rise to a revision of several parts of the DIN 25482 and ISO 11929 standard series. These series stipulate detection limits and decision thresholds for ionizing-radiation measurements. Part 3 and, respectively, part 4 of them deal with measurements by use of linear-scale analogue ratemeters. A normal frequency distribution of the momentary ratemeter indication for a fixed count rate value is assumed. The actual distribution, which is first calculated numerically by solving an integral equation, differs, however, considerably from the normal distribution although this one represents an approximation of it for sufficiently large values of the count rate to be measured. As is shown, this similarly holds true for the Bayesian probability distribution of the count rate for sufficiently large given measured values indicated by the ratemeter. This distribution follows from the first one mentioned by means of the Bayes theorem. Its expectation value and variance are needed for the standards to be revised on the basis of Bayesian statistics. Simple expressions are given by the present standards for estimating these parameters and for calculating the detection limit and the decision threshold. As is also shown, the same expressions can similarly be used as sufficient approximations by the revised standards if, roughly, the present indicated value exceeds the reciprocal ratemeter relaxation time constant. (orig.)

  4. Genetic influence of radiation measured by the effect on the mutation rate of human minisatellite genes

    International Nuclear Information System (INIS)

    Kodaira, Mieko

    2002-01-01

    Human minisatellite genes are composed from 0.1-30 kb with a high frequency of polymorphism. The genes exist in mammalian genomes and mice's ones are well studied after irradiation of their gonad cells by X-ray and γ-ray. Following five reports concerning the significant and/or insignificant increases of the mutation rate of the genes post A-bomb exposure, Chernobyl accident and nuclear weapons test in Semipalatinsk are reviewed and discussed on the subject number, exposed dose, problems of the control group, regions examined of loci and exposure conditions. Genetic influences of radiation examined by the author's facility are not recognized in the mutation rate (3.21% vs 4.94% in the control) of minisatellite genes in children of A-bomb survivors and their parents. The mutation rates are 4.27 vs 2.52% (positive influence) and 4.2-6.01% vs 3.5-6.34% in Chernobyl, and 4.3 (parents) and 3.8% (F 1 ) vs 2.5% (positive). Mutation of human minisatellite genes can be an important measure of genetic influences at the medical level. (K.H.)

  5. Radiation dose rate map interpolation in nuclear plants using neural networks and virtual reality techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mol, Antonio Carlos A., E-mail: mol@ien.gov.br [Comissao Nacional de Energia Nuclear, Instituto de Engenharia Nuclear Rua Helio de Almeida, 75, Ilha do Fundao, P.O. Box 68550, 21941-906 Rio de Janeiro, RJ (Brazil); Instituto Nacional de Ciencia e Tecnologia de Reatores Nucleares Inovadores/CNPq (Brazil); Pereira, Claudio Marcio N.A., E-mail: cmnap@ien.gov.br [Comissao Nacional de Energia Nuclear, Instituto de Engenharia Nuclear Rua Helio de Almeida, 75, Ilha do Fundao, P.O. Box 68550, 21941-906 Rio de Janeiro, RJ (Brazil); Instituto Nacional de Ciencia e Tecnologia de Reatores Nucleares Inovadores/CNPq (Brazil); Freitas, Victor Goncalves G. [Universidade Federal do Rio de Janeiro, Programa de Engenharia Nuclear, Rio de Janeiro, RJ (Brazil); Jorge, Carlos Alexandre F., E-mail: calexandre@ien.gov.br [Comissao Nacional de Energia Nuclear, Instituto de Engenharia Nuclear Rua Helio de Almeida, 75, Ilha do Fundao, P.O. Box 68550, 21941-906 Rio de Janeiro, RJ (Brazil)

    2011-02-15

    This paper reports the most recent development results of a simulation tool for assessment of radiation dose exposition by nuclear plant's personnel, using artificial intelligence and virtual reality technologies. The main purpose of this tool is to support training of nuclear plants' personnel, to optimize working tasks for minimisation of received dose. A finer grid of measurement points was considered within the nuclear plant's room, for different power operating conditions. Further, an intelligent system was developed, based on neural networks, to interpolate dose rate values among measured points. The intelligent dose prediction system is thus able to improve the simulation of dose received by personnel. This work describes the improvements implemented in this simulation tool.

  6. Radiation dose rate map interpolation in nuclear plants using neural networks and virtual reality techniques

    International Nuclear Information System (INIS)

    Mol, Antonio Carlos A.; Pereira, Claudio Marcio N.A.; Freitas, Victor Goncalves G.; Jorge, Carlos Alexandre F.

    2011-01-01

    This paper reports the most recent development results of a simulation tool for assessment of radiation dose exposition by nuclear plant's personnel, using artificial intelligence and virtual reality technologies. The main purpose of this tool is to support training of nuclear plants' personnel, to optimize working tasks for minimisation of received dose. A finer grid of measurement points was considered within the nuclear plant's room, for different power operating conditions. Further, an intelligent system was developed, based on neural networks, to interpolate dose rate values among measured points. The intelligent dose prediction system is thus able to improve the simulation of dose received by personnel. This work describes the improvements implemented in this simulation tool.

  7. Radiative rates for E1, E2, M1 and M2 transitions in Fe X

    International Nuclear Information System (INIS)

    Aggarwal, K.M.; Keenan, F.P.

    2004-01-01

    Energies of the 54 levels belonging to the (1s 2 2s 2 2p 6 ) 3s 2 3p 5 , 3s3p 6 , 3s 2 3p 4 3d and 3s3p 5 3d configurations of Fe X have been calculated using the GRASP code of Dyall and colleagues (1989). Additionally, radiative rates, oscillator strengths, and line strengths are calculated for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among these levels. Comparisons are made with results available in the literature, and the accuracy of the data is assessed. Our energy levels are estimated to be accurate to better than 3%, whereas results for other parameters are probably accurate to better than 20% . Additionally, the agreement between measured and calculated lifetimes is better than 10%. (authors)

  8. High-dose-rate intraoperative radiation therapy: the nuts and bolts of starting a program

    Science.gov (United States)

    Moningi, Shalini; Armour, Elwood P.; Terezakis, Stephanie A.; Efron, Jonathan E.; Gearhart, Susan L.; Bivalacqua, Trinity J.; Kumar, Rachit; Le, Yi; Kien Ng, Sook; Wolfgang, Christopher L.; Zellars, Richard C.; Ellsworth, Susannah G.; Ahuja, Nita

    2014-01-01

    High-dose-rate intraoperative radiation therapy (HDR-IORT) has historically provided effective local control (LC) for patients with unresectable and recurrent tumors. However, IORT is limited to only a few specialized institutions and it can be difficult to initiate an HDR-IORT program. Herein, we provide a brief overview on how to initiate and implement an HDR-IORT program for a selected group of patients with gastrointestinal and pelvic solid tumors using a multidisciplinary approach. Proper administration of HDR-IORT requires institutional support and a joint effort among physics staff, oncologists, surgeons, anesthesiologists, and nurses. In order to determine the true efficacy of IORT for various malignancies, collaboration among institutions with established IORT programs is needed. PMID:24790628

  9. RD Collaboration Proposal: Development of pixel readout integrated circuits for extreme rate and radiation

    CERN Document Server

    Chistiansen, J (CERN)

    2013-01-01

    This proposal describes a new RD collaboration to develop the next genrration of hybrid pixel readout chips for use in ATLAS and CMS PHase 2 upgrades. extrapolation of hybrid pixel technology to the HL-LHC presents major challenges on several fronts. Challenges include: smaller pixels to resolve tracks in boosted jets, much higher hit rates (1-2 GHz/cm2 ), unprecedented radiation tolerance (10 MGy), much higher output bandwidth, and large IC format with low power consumption in order to instrument large areas while keeping the material budget low. This collaboration is specifically focused on design of hybrid pixel readout chips, and not on more general chip design or on other aspects of hybrid pixel technology. Participants include 7 institutes on ATLAS and 7 on CMS, plus 2 on both experiments.

  10. Error-Rate Estimation Based on Multi-Signal Flow Graph Model and Accelerated Radiation Tests.

    Directory of Open Access Journals (Sweden)

    Wei He

    Full Text Available A method of evaluating the single-event effect soft-error vulnerability of space instruments before launched has been an active research topic in recent years. In this paper, a multi-signal flow graph model is introduced to analyze the fault diagnosis and meantime to failure (MTTF for space instruments. A model for the system functional error rate (SFER is proposed. In addition, an experimental method and accelerated radiation testing system for a signal processing platform based on the field programmable gate array (FPGA is presented. Based on experimental results of different ions (O, Si, Cl, Ti under the HI-13 Tandem Accelerator, the SFER of the signal processing platform is approximately 10-3(error/particle/cm2, while the MTTF is approximately 110.7 h.

  11. Real time monitoring automation of dose rate absorbed in air due to environmental gamma radiation

    International Nuclear Information System (INIS)

    Dominguez Ley, Orlando; Capote Ferrera, Eduardo; Carrazana Gonzalez, Jorge A.; Manzano de Armas, Jose F.; Alonso Abad, Dolores; Prendes Alonso, Miguel; Tomas Zerquera, Juan; Caveda Ramos, Celia A.; Kalber, Olof; Fabelo Bonet, Orlando; Montalvan Estrada, Adelmo; Cartas Aguila, Hector; Leyva Fernandez, Julio C.

    2005-01-01

    The Center of Radiation Protection and Hygiene (CPHR) as the head institution of the National Radiological Environmental Surveillance Network (RNVRA) has strengthened its detection and response capacity for a radiological emergency situation. The measurements of gamma dose rate at the main point of the RNVRA are obtained in real time and the CPHR receives the data coming from those points in a short time. To achieve the operability of the RNVRA it was necessary to complete the existent monitoring facilities using 4 automatic gamma probes, implementing in this way a real time measurement system. The software, GenitronProbe for obtaining the data automatically from the probe, Data Mail , for sending the data via e-mail, and Gamma Red , for receiving and processing the data in the head institution ,were developed

  12. Energy levels and radiative transition rates for Ge XXXI, As XXXII, and Se XXXIII

    Science.gov (United States)

    Aggarwal, Sunny; Singh, J.; Jha, A. K. S.; Mohan, Man

    2014-07-01

    Fine-structure energies of the 67 levels belonging to the 1s2, 1s 2l, 1s3l, 1s4l, 1s5l, and 1s6l configurations of Ge XXXI, As XXXII, and Se XXXIII have been calculated using the General-Purpose Relativistic Atomic Structure Package. In addition, radiative rates, oscillator strengths, transition wavelengths, and line strengths have been calculated for all electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transitions among these levels. Lifetimes are also presented for all excited levels of these three ions. We have compared our results with the results available in the literature and the accuracy of the data is assessed. We predict new energy levels, oscillator strengths, and transition probabilities where no other theoretical or experimental results are available, which will form the basis for future experimental work.

  13. High-dose rate intra-operative radiation therapy for local advanced and recurrent colorectal cancer

    International Nuclear Information System (INIS)

    Harrison, L.B.; Mychalczak, B.; Enker, W.; Anderson, L.; Cohen, A.E.; Minsky, B.

    1996-01-01

    In an effort to improve the local control for advanced and recurrent cancers of the rectum, we have integrated high-dose rate intra-operative radiation therapy (HDR-IORT) into the treatment program. Between 11/92 and 10/95, 47 patients (pts) were treated. There were 26 males and 21 females whose ages ranged from 30-80 (median = 62) years. There were 19 pts with primary unresectable rectal cancer, and 28 pts who were treated for recurrent rectal cancer. Histology was adenocarcinoma - 45 pts, squamous cancer - 2 pts. The range of follow-up is 1-34 months (median = 14 months). The majority of primary unresectable pts received pre-operative radiation therapy (4500-5040 cGy) with chemotherapy (5-FU with Leucovorin) 4-6 weeks later, they underwent resection + HDR-IORT (1200 cGy). For the 28 pts with recurrent cancer, the majority received surgery and HDR-IORT alone because they had received prior RT. For the pts with primary unresectable disease, actuarial 2-year local control was 77%, actuarial distant metastasis-free survival was 71%, disease free survival was 66%, and overall survival was 84%. For those pts with recurrent disease, actuarial 2-year local control rate was 65%, distant metastasis-free survival was 65%, disease free survival was 47%, and overall survival was 61%. Complications occurred in 36%. There were no cases where the anatomical distribution of disease, or technical limitations prevented the adequate delivery of HDR-IORT. We conclude that this technique was most versatile, and enabled all appropriate pts to receive IORT. The preliminary data in terms of local control are encouraging, even for the poor prognostic sub-group of pts with recurrent cancer

  14. Effects of combined radiation-burn injury on survival rate of allogeneic skin grafts and immune reaction in rats

    International Nuclear Information System (INIS)

    Ran Xinze; Yan Yongtang; Cheng Tianmin; Li Yuan; Wei Shuqing

    1996-01-01

    The effects of combined radiation-burn injury on survival rate of allogeneic skin grafts and immune reaction were studied in rats with combined injury of 3-8 Gy 60 Co γ-ray irradiation plus 15% total body surface area full thickness burn induced by exposure to a 5 kw bromotungsten lamp. The allogeneic skin was transplanted 24 hours after injury. It was found that all the skin grafts failed to survive in 10 days and the immune reaction significantly increased in the early stage of burn injury. But the immune reaction was obviously suppressed by the combined radiation-burn injury. The survival rates of skin grafts were 20% and 30% in the combined injury of burn plus 3 and 4 Gy irradiation respectively. When the radiation doses increased to 5,6 and 8 Gy, the survival rates elevated to 69%, 88% and 100% respectively (in the group of 8 Gy, bone marrow transplantation was conducted before receiving skin graft). At day 30 post-transplantation the survival rates were still 36%, 42% and 100% respectively. Compared with burn group, there was a significant difference in survival rate when the radiation doses were higher than 5 Gy. These results indicate that the survival rate of the allogeneic skin graft increases concurrently with the increase in radiation dose and decreases with the elapse of the post-transplantation time

  15. Chromosomal Aberrations in DNA Repair Defective Cell Lines: Comparisons of Dose Rate and Radiation Quality

    Science.gov (United States)

    George, K. A.; Hada, M.; Patel, Z.; Huff, J.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Chromosome aberration yields were assessed in DNA double-strand break repair (DSB) deficient cells after acute doses of gamma-rays or high-LET iron nuclei, or low dose-rate (0.018 Gy/hr) gamma-rays. We studied several cell lines including fibroblasts deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase, DNA-PK activity. Chromosomes were analyzed using the fluorescence in-situ hybridization (FISH) chromosome painting method in cells at the first division post-irradiation and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma radiation induced higher yields of both simple and complex exchanges in the DSB repair defective cells than in the normal cells. The quadratic dose-response terms for both chromosome exchange types were significantly higher for the ATM and NBS defective lines than for normal fibroblasts. However, the linear dose-response term was significantly higher only for simple exchanges in the NBS cells. Large increases in the quadratic dose response terms indicate the important roles of ATM and NBS in chromatin modifications that facilitate correct DSB repair and minimize aberration formation. Differences in the response of AT and NBS deficient cells at lower doses suggests important questions about the applicability of observations of radiation sensitivity at high dose to low dose exposures. For all iron nuclei irradiated cells, regression models preferred purely linear and quadratic dose responses for simple and complex exchanges, respectively. All the DNA repair defective cell lines had lower Relative biological effectiveness (RBE) values than normal cells, the lowest being for the DNA-PK-deficient cells, which was near unity. To further

  16. Global radiation damage at 300 and 260 K with dose rates approaching 1 MGy s{sup −1}

    Energy Technology Data Exchange (ETDEWEB)

    Warkentin, Matthew; Badeau, Ryan; Hopkins, Jesse B. [Cornell University, Ithaca, NY 14853 (United States); Mulichak, Anne M.; Keefe, Lisa J. [Argonne National Laboratory, Argonne, IL 60439 (United States); Thorne, Robert E., E-mail: ret6@cornell.edu [Cornell University, Ithaca, NY 14853 (United States)

    2012-02-01

    Approximately half of global radiation damage to thaumatin crystals can be outrun at 260 K if data are collected in less than 1 s. Global radiation damage to 19 thaumatin crystals has been measured using dose rates from 3 to 680 kGy s{sup −1}. At room temperature damage per unit dose appears to be roughly independent of dose rate, suggesting that the timescales for important damage processes are less than ∼1 s. However, at T = 260 K approximately half of the global damage manifested at dose rates of ∼10 kGy s{sup −1} can be outrun by collecting data at 680 kGy s{sup −1}. Appreciable sample-to-sample variability in global radiation sensitivity at fixed dose rate is observed. This variability cannot be accounted for by errors in dose calculation, crystal slippage or the size of the data sets in the assay.

  17. The effect of low dose rate on metabolomic response to radiation in mice

    International Nuclear Information System (INIS)

    Goudarzi, Maryam; Mak, Tytus D.; Chen, Congju; Smilenov, Lubomir B.; Brenner, David J.; Fornace, Albert J.

    2014-01-01

    Metabolomics has been shown to have utility in assessing responses to exposure by ionizing radiation (IR) in easily accessible biofluids such as urine. Most studies to date from our laboratory and others have employed γ-irradiation at relatively high dose rates (HDR), but many environmental exposure scenarios will probably be at relatively low dose rates (LDR). There are well-documented differences in the biologic responses to LDR compared to HDR, so an important question is to assess LDR effects at the metabolomics level. Our study took advantage of a modern mass spectrometry approach in exploring the effects of dose rate on the urinary excretion levels of metabolites 2 days after IR in mice. A wide variety of statistical tools were employed to further focus on metabolites, which showed responses to LDR IR exposure (0.00309 Gy/min) distinguishable from those of HDR. From a total of 709 detected spectral features, more than 100 were determined to be statistically significant when comparing urine from mice irradiated with 1.1 or 4.45 Gy to that of sham-irradiated mice 2 days post-exposure. The results of this study show that LDR and HDR exposures perturb many of the same pathways such as TCA cycle and fatty acid metabolism, which also have been implicated in our previous IR studies. However, it is important to note that dose rate did affect the levels of particular metabolites. Differences in urinary excretion levels of such metabolites could potentially be used to assess an individual's exposure in a radiobiological event and thus would have utility for both triage and injury assessment. (orig.)

  18. Comparison of radiation and quenching rate effects on the structure of a sodium borosilicate glass

    International Nuclear Information System (INIS)

    Peuget, Sylvain; Maugeri, Emilio-Andrea; Mendoza, Clement; Fares, Toby; Bouty, Olivier; Jegou, Christophe; Charpentier, Thibault; Moskura, Melanie

    2013-01-01

    The effects of quenching rate and irradiation on the structure of a sodium borosilicate glass were compared using 29 Si, 11 B, and 23 Na nuclear magnetic resonance and Raman spectroscopy. Quenching rate ranging from 0.1 to 3 * 10 4 K min -1 was studied. Various irradiation conditions were performed, i.e. gold-ion irradiation in a multi-energy mode (from 1 to 6.75 MeV), and Kr and Xe ion irradiations with energy of 74 and 92 MeV, respectively. In pile irradiation with thermal neutron flux was performed as well, to study the effect of alpha radiation from the nuclear reaction 10 B(n,α) 7 Li. Both irradiation and high quenching rate induce similar local order modification of the glass structure, mainly a decrease of the mean boron coordination and an increase of Q 3 units. Nevertheless, the variations observed under irradiation are more pronounced than the ones induced by the quenching rate. Moreover, some important modifications of the glass medium range order, i.e. the emergence of the D2 band associated to three members silica rings and a modification of the Si-O-Si angle distribution were only noticed after irradiation. These results suggest that the irradiated structure is certainly not exactly the one obtained by a rapidly quenched equilibrated melt, but rather a more disordered structure that was weakly relaxed during the very rapid quenching phase following the energy deposition step. Raman spectroscopy showed a similar irradiated structure whereas the glass evolutions were controlled by the electronic energy loss in the ion track formation regime for Kr-ion irradiation or by the nuclear energy loss for Au and OSIRIS irradiation. The similar irradiated structure despite different irradiation routes, suggests that the final structural state of this sodium borosilicate glass is mainly controlled by the glass reconstruction after the energy deposition step. (authors)

  19. Low and high dose rate heavy ion radiation-induced intestinal and colonic tumorigenesis in APC1638N/+ mice

    Science.gov (United States)

    Suman, Shubhankar; Kumar, Santosh; Moon, Bo-Hyun; Fornace, Albert J.; Datta, Kamal

    2017-05-01

    Ionizing radiation (IR) is a recognized risk factor for colorectal cancer (CRC) and astronauts undertaking long duration space missions are expected to receive IR doses in excess of permissible limits with implications for colorectal carcinogenesis. Exposure to IR in outer space occurs at low doses and dose rates, and energetic heavy ions due to their high linear energy transfer (high-LET) characteristics remain a major concern for CRC risk in astronauts. Previously, we have demonstrated that intestinal tumorigenesis in a mouse model (APC1638N/+) of human colorectal cancer was significantly higher after exposure to high dose rate energetic heavy ions relative to low-LET γ radiation. The purpose of the current study was to compare intestinal tumorigenesis in APC1638N/+ mice after exposure to energetic heavy ions at high (50 cGy/min) and relatively low (0.33 cGy/min) dose rate. Male and female mice (6-8 weeks old) were exposed to either 10 or 50 cGy of 28Si (energy: 300 MeV/n; LET: 70 keV/μm) or 56Fe (energy: 1000 MeV/n; LET: 148 keV/μm) ions at NASA Space Radiation Laboratory in Brookhaven National Laboratory. Mice (n = 20 mice/group) were euthanized and intestinal and colon tumor frequency and size were counted 150 days after radiation exposure. Intestinal tumorigenesis in male mice exposed to 56Fe was similar for high and low dose rate exposures. Although male mice showed a decreasing trend at low dose rate relative to high dose rate exposures, the differences in tumor frequency between the two types of exposures were not statistically significant after 28Si radiation. In female mice, intestinal tumor frequency was similar for both radiation type and dose rates tested. In both male and female mice intestinal tumor size was not different after high and low dose rate radiation exposures. Colon tumor frequency in male and female mice after high and low dose rate energetic heavy ions was also not significantly different. In conclusion, intestinal and colonic tumor

  20. Impedancia esofágica intraluminal de canal múltiple: una nueva frontera en motilidad Multichannel intraluminal esophageal impedance: A new frotier in motility

    Directory of Open Access Journals (Sweden)

    F. de la Morena

    2008-02-01

    Full Text Available La impedancia esofágica multicanal constituye una de las más recientes herramientas diagnósticas aplicadas a la evaluación de la enfermedad por reflujo gastroesofágico. Esta técnica se basa en la monitorización continua de la conductividad eléctrica en un medio, en este caso el esófago, a través de electrodos situados en la longitud de una sonda, y en los cambios que un elemento como el bolo alimentario puede producir en dicha variable. De esta técnica se derivan nuevas perspectivas en la exploración de la función esofágica y de la enfermedad por reflujo gastroesofágico, hasta ahora sólo cuantificable de forma indirecta por las fluctuaciones generadas por los cambios en el pH del reflujo ácido. Presentamos el caso de una paciente con tos persistente evaluada con este procedimiento, en quien se demostró la presencia de reflujo gastroesofágico débilmente ácido que no pudo ser demostrado previamente con otras exploraciones, y de cómo la impedancia descartó la asociación entre este síntoma y el reflujo no ácido.Multichannel intraluminal impedance is a new technique for evaluating esophageal function and gastroesophageal reflux disease (GERD. This technique relies on the monitoring of electric conductivity in the esophagus though electrodes, and on changes developing in this variable as a result of bolus passage. The proximal distribution and duration of non-acid reflux events can now be quantified, and combined manometry defines the effectiveness of esophageal body function, until now only indirectly evaluated with pH changes. We discuss the case of a woman with persistent cough in whom intraesophageal multichannel impedance demostrates a minor acid reflux that could not be demonstrated with other diagnostic methods previously, and how this technique excludes any association between cough and non-acid reflux.

  1. Effect of infrared and X-ray radiation on thymus cells and the rate of growth of Ehrlich carcinoma.

    Science.gov (United States)

    Dyukina, A R; Zaichkina, S I; Rozanova, O M; Aptikaeva, G F; Romanchenko, S P; Sorokina, S S

    2012-09-01

    We studied the effect of infrared light with a wavelength of 850 nm and modulated frequency of 101 Hz and X-ray radiation on the induction of cross-adaptive and radiation responses in the thymus and on the rate of tumor growth in mice in vivo. Preliminary exposure to infrared and X-ray radiation was shown to result in recovery in thymus weight after irradiation in a dose of 1.5 Gy and also inhibited the growth rate of Ehrlich carcinoma. These data attest to common mechanisms of the adaptive response induced by infrared and X-ray radiation in mice. Infrared light can be used as an adaptogen to adapt the animals to adverse factors.

  2. The effects of radiation dose-rate and quality on the induction of dominant lethals in mouse spermatids

    International Nuclear Information System (INIS)

    Searle, A.G.; Beechey, G.V.

    1981-01-01

    Hybrid male mice were given 3 Gy (300 rad) doses of X- or γ-irradiation at dose-rates of either 0.6 or 0.002 Gy/min for each radiation. Germ-cells treated as spermatids were tested for dominant lethality. Effects on spermatogonia were evaluated by studying testis-weight, sperm-count and sperm abnormalities. The rate of induction of dominant lethal mutations was 2.1 times as high after acute X-irradiation as after protracted γ-irradiation. Most of this difference resulted from the change in radiation quality, since the relative effectiveness of X- versus γ-irradiation was 1.9 at low and 1.6 at high dose rates. For each radiation, however, fewer dominant lethals were induced at low dose-rates than at high (low/high ratios of 0.8 and 0.9 respectively) although differences did not reach a significant level. There were no statistically significant effects of dose rate on testis-weight of sperm-count in the X-ray series, but there were significantly less severe effects on both with protraction of the γ-irradiation. Evidence for effects of radiation quality on these characters was conflicting. Frequencies of abnormal spermatozoa were markedly increased 7 weeks after irradiation but there were no consistent effects of radiation intensity or quality. (orig.)

  3. Overall response rates to radiation therapy for patients with painful uncomplicated bone metastases undergoing initial treatment and retreatment

    International Nuclear Information System (INIS)

    Bedard, Gillian; Hoskin, Peter; Chow, Edward

    2014-01-01

    Introduction: Radiation therapy has been shown to successfully palliate bone metastases. A number of systematic reviews and large clinical trials have reported response rates for initial treatment and retreatment. Objective: To determine overall response rates of patients with painful uncomplicated bone metastases undergoing initial treatment and retreatment. Methods: Intent-to-treat and evaluable patient statistics from a systematic review of palliative radiotherapy trials for initial treatment of bone metastases and a randomized clinical trial of retreatment were pooled and analyzed to determine the overall response rates for patients receiving initial treatment and retreatment. Results: In the intent-to-treat calculation, 71–73% of patients had an overall response to radiation treatment and in the evaluable patient population; 85–87% of patients did so. Response rates varied slightly whether patients underwent single or multiple fractions in initial treatment or retreatment. Conclusions: Single and multiple fraction radiation treatment yielded very similar overall response rates. Patients treated with a single fraction for both initial and repeat radiation experience almost identical overall response to those patients treated with multiple fraction treatment. It is therefore recommended that patients with uncomplicated painful bone metastases be treated with a single 8 Gy fraction of radiation at both the initial treatment and retreatment

  4. Measurement of the radiative cooling rates for high-ionization species of krypton using an electron beam ion trap

    International Nuclear Information System (INIS)

    Radtke, R.; Biedermann, C.; Fuchs, T.; Fussmann, G.; Beiersdorfer, P.

    2000-01-01

    We describe a measurement of the radiative cooling rate for krypton made at the Berlin electron beam ion trap (EBIT). The EBIT was tuned to a charge-state distribution approaching the ionization balance of a plasma at a temperature of about 5 keV. To determine the cooling rate, we made use of EBIT's capabilities to sample a wide range of electron-beam energies and distinguish between different radiation channels. We have measured the x-ray emission from bremsstrahlung, radiative recombination, dielectronic recombination, and line radiation following electron-impact excitation. The dominant contribution to the cooling rate is made by the n=3-2, n=4-2,... x rays of the L-shell spectra of krypton, which produce more than 75% of the total radiation loss. A difference with theoretical calculations is noted for the measured total cooling rate. The predicted values are lower by a factor of 1.5-2, depending on the theoretical model. For our measurement of the cooling rate, we estimate an uncertainty interval of 22-30 %. (c) 2000 The American Physical Society

  5. Temperature variation of non-radiative recombination rate in a-Si:H films

    Energy Technology Data Exchange (ETDEWEB)

    Ogihara, C. [Department of Applied Science, Yamaguchi University, Ube 755-8611 (Japan); Morigaki, K. [Department of Electrical and Digital-System Engineering, Hiroshima Institute of Technology, Miyake, Saeki-ku, Hiroshima 731-5193 (Japan); resent address: C-305, 2-12 Wakabadai, Inagi, Tokyo 206-0824 (Japan)

    2012-12-15

    Temperature variation of the recombination rates has been investigated for the electron-hole pairs responsible for defect PL in a defective a-Si:H film as grown. The results are compared with those obtained for a high-quality a-Si:H film after illumination. The results of the nonradiative recombination rate are fitted by a theoretical prediction for the case of strong electron-phonon coupling in the case of the defective a-Si:H film similarly to the case of the illuminated high-quality a-Si:H film. Difference between the frequency of the phonon associated with the non-radiative recombination process in the defective a-Si:H film and that in the illuminated highquality a-Si:H film is discussed by considering the influence of the amorphous network in the a-Si:H films affected by the preparation conditions and the nature of the native and photo-created defects. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Results of radiation therapy for uterine cervical cancer using high dose rate remote after loading system

    International Nuclear Information System (INIS)

    Ogawa, Yoshihiro; Nemoto, Kenji

    2003-01-01

    In Japan, radiotherapy with high dose rate remote after loading system (HDR-RALS) for intracavitary brachytherapy is the standard treatment for more than 30 years. This report showed the usefulness of HDR-RALS for uterine cervical cancer. From 1980 through 1999, 442 patients with uterine cervical cancers (stage I: 66, stage II: 161, stage III: 165, stage IV: 50) were treated. Radiotherapy was performed both external teletherapy and HDR-RALS. Overall survival rate at 5 years was 60.2%. The 5-year actuarial incidence of all complications was 16.4%. The 5-year actuarial incidence of all complications in cases treated with the sum doses of whole pelvic irradiation (without central shield) and RALS up to 49 Gy, 50 to 59 Gy or larger doses were 7.5%, 11.0% and 25.2%, respectively. Radiation therapy using HDR-RALS was very effective. While the dose of whole pelvic irradiation was increased, the actuarial incidence of all complications was increased. (author)

  7. Volumetric modulated arc therapy for lung stereotactic radiation therapy can achieve high local control rates.

    Science.gov (United States)

    Yamashita, Hideomi; Haga, Akihiro; Takahashi, Wataru; Takenaka, Ryousuke; Imae, Toshikazu; Takenaka, Shigeharu; Nakagawa, Keiichi

    2014-11-11

    The aim of this study was to report the outcome of primary or metastatic lung cancer patients undergoing volumetric modulated arc therapy for stereotactic body radiation therapy (VMAT-SBRT). From October 2010 to December 2013, consecutive 67 lung cancer patients received single-arc VMAT-SBRT using an Elekta-synergy system. All patients were treated with an abdominal compressor. The gross tumor volumes were contoured on 10 respiratory phases computed tomography (CT) datasets from 4-dimensional (4D) CT and merged into internal target volumes (ITVs). The planning target volume (PTV) margin was isotropically taken as 5 mm. Treatment was performed with a D95 prescription of 50 Gy (43 cases) or 55 Gy (12 cases) in 4 fractions for peripheral tumor or 56 Gy in 7 fractions (12 cases) for central tumor. Among the 67 patients, the median age was 73 years (range, 59-95 years). Of the patients, male was 72% and female 28%. The median Karnofsky performance status was 90-100% in 39 cases (58%) and 80-90% in 20 cases (30%). The median follow-up was 267 days (range, 40-1162 days). Tissue diagnosis was performed in 41 patients (61%). There were T1 primary lung tumor in 42 patients (T1a in 28 patients, T1b in 14 patients), T2 in 6 patients, three T3 in 3 patients, and metastatic lung tumor in 16 patients. The median mean lung dose was 6.87 Gy (range, 2.5-15 Gy). Six patients (9%) developed radiation pneumonitis required by steroid administration. Actuarial local control rate were 100% and 100% at 1 year, 92% and 75% at 2 years, and 92% and 75% at 3 years in primary and metastatic lung cancer, respectively (p =0.59). Overall survival rate was 83% and 84% at 1 year, 76% and 53% at 2 years, and 46% and 20% at 3 years in primary and metastatic lung cancer, respectively (p =0.12). Use of VMAT-based delivery of SBRT in primary in metastatic lung tumors demonstrates high local control rates and low risk of normal tissue complications.

  8. Volumetric modulated arc therapy for lung stereotactic radiation therapy can achieve high local control rates

    International Nuclear Information System (INIS)

    Yamashita, Hideomi; Haga, Akihiro; Takahashi, Wataru; Takenaka, Ryousuke; Imae, Toshikazu; Takenaka, Shigeharu; Nakagawa, Keiichi

    2014-01-01

    The aim of this study was to report the outcome of primary or metastatic lung cancer patients undergoing volumetric modulated arc therapy for stereotactic body radiation therapy (VMAT-SBRT). From October 2010 to December 2013, consecutive 67 lung cancer patients received single-arc VMAT-SBRT using an Elekta-synergy system. All patients were treated with an abdominal compressor. The gross tumor volumes were contoured on 10 respiratory phases computed tomography (CT) datasets from 4-dimensional (4D) CT and merged into internal target volumes (ITVs). The planning target volume (PTV) margin was isotropically taken as 5 mm. Treatment was performed with a D95 prescription of 50 Gy (43 cases) or 55 Gy (12 cases) in 4 fractions for peripheral tumor or 56 Gy in 7 fractions (12 cases) for central tumor. Among the 67 patients, the median age was 73 years (range, 59–95 years). Of the patients, male was 72% and female 28%. The median Karnofsky performance status was 90-100% in 39 cases (58%) and 80-90% in 20 cases (30%). The median follow-up was 267 days (range, 40–1162 days). Tissue diagnosis was performed in 41 patients (61%). There were T1 primary lung tumor in 42 patients (T1a in 28 patients, T1b in 14 patients), T2 in 6 patients, three T3 in 3 patients, and metastatic lung tumor in 16 patients. The median mean lung dose was 6.87 Gy (range, 2.5-15 Gy). Six patients (9%) developed radiation pneumonitis required by steroid administration. Actuarial local control rate were 100% and 100% at 1 year, 92% and 75% at 2 years, and 92% and 75% at 3 years in primary and metastatic lung cancer, respectively (p = 0.59). Overall survival rate was 83% and 84% at 1 year, 76% and 53% at 2 years, and 46% and 20% at 3 years in primary and metastatic lung cancer, respectively (p = 0.12). Use of VMAT-based delivery of SBRT in primary in metastatic lung tumors demonstrates high local control rates and low risk of normal tissue complications

  9. Energy levels, radiative rates and electron impact excitation rates for transitions in He-like Ga XXX, Ge XXXI, As XXXII, Se XXXIII and Br XXXIV

    International Nuclear Information System (INIS)

    Aggarwal, Kanti M; Keenan, Francis P

    2013-01-01

    We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in He-like Ga XXX, Ge XXXI, As XXXII, Se XXXIII and Br XXXIV. The grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates. For determining the collision strengths, and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels of each ion. Additionally, theoretical lifetimes are provided for all 49 levels of the above five ions. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 10 8 K. Comparisons are made with similar data obtained using the flexible atomic code (fac) to highlight the importance of resonances, included in calculations with darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, particularly for some forbidden transitions, are also discussed. Finally, discrepancies between the present results for effective collision strengths with the darc code and earlier semi-relativistic R-matrix data are noted over a wide range of electron temperatures for many transitions in all ions. (paper)

  10. Energy levels, radiative rates and electron impact excitation rates for transitions in He-like Ga XXX, Ge XXXI, As XXXII, Se XXXIII and Br XXXIV

    Science.gov (United States)

    Aggarwal, Kanti M.; Keenan, Francis P.

    2013-04-01

    We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in He-like Ga XXX, Ge XXXI, As XXXII, Se XXXIII and Br XXXIV. The grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates. For determining the collision strengths, and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels of each ion. Additionally, theoretical lifetimes are provided for all 49 levels of the above five ions. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 108 K. Comparisons are made with similar data obtained using the flexible atomic code (fac) to highlight the importance of resonances, included in calculations with darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, particularly for some forbidden transitions, are also discussed. Finally, discrepancies between the present results for effective collision strengths with the darc code and earlier semi-relativistic R-matrix data are noted over a wide range of electron temperatures for many transitions in all ions.

  11. 110. PTB seminar: Dose rate measurements of ionizing radiation in the range of natural ambient radiation. Proceedings

    International Nuclear Information System (INIS)

    Lauterbach, U.; Pessara, W.; Woehler-Figgen, S.

    1997-12-01

    Measuring instruments for radiation dose measurement in the range of natural ambient radiation are not subject to legal obligations for calibration and the PTB received numerous requests in the past, asking for measures to be taken in order to ensure reliability of measuring results in this range of radiation. This has induced PTB to organise the seminar, intended to present the current status of measuring technology in this field, reveal problems encountered in practical applications, and discuss suitable ction for quality assurance. The papers of the seminar report the measuring performance and capabilities of the available instruments, results of comparative analyses of measurements, and resulting proposed action for quality assurance. Discussions concluding the sessions are also presented in the processdings volume. (orig./CB) [de

  12. Esophageal intraluminal baseline impedance differentiates gastroesophageal reflux disease from functional heartburn.

    Science.gov (United States)

    Kandulski, Arne; Weigt, Jochen; Caro, Carlos; Jechorek, Doerthe; Wex, Thomas; Malfertheiner, Peter

    2015-06-01

    Mucosal integrity can be assessed in patients with gastroesophageal reflux disease (GERD) by measuring intraluminal baseline impedance (BI). However, it is not clear whether BI is abnormal in patients with functional heartburn (FH), or can be used to distinguish them from patients with GERD. We compared differences in BI between patients with FH vs GERD. We performed a prospective study of 52 patients (16 men; mean age, 55 y; range, 23-78 y) seen at a tertiary university hospital from February 2009 through December 2012. Thirty-five patients had GERD (19 had nonerosive reflux disease [NERD], 16 had erosive reflux disease [ERD]) and 17 had FH. All patients discontinued proton pump inhibitor therapy and then underwent esophagogastroduodenoscopy and multichannel intraluminal impedance and pH monitoring. BI was assessed at 3, 5, 7, 9, 15, and 17 cm proximal to the lower esophageal sphincter in recumbent patients. Biopsy specimens were taken from 3 cm above the gastroesophageal junction; histology analysis was performed to identify and semiquantitatively score (scale, 0-3) dilated intercellular spaces. Baseline impedance in the distal esophagus was significantly lower in patients with NERD or erosive reflux disease (ERD) than FH (P = .0006). At a cut-off value of less than 2100 Ω, BI measurements identified patients with GERD with 78% sensitivity and 71% specificity, with positive and negative predictive values of 75%. Also in the proximal esophagus, reduced levels of BI levels were found only in patients with ERD. There were negative correlations between level of BI and acid exposure time (r = -0.45; P = .0008), number of acidic reflux episodes (r = -0.45; P = .001), and proximal extent (r = -0.40; P = .004). Biopsy specimens from patients with NERD or ERD had significant increases in dilation of intercellular spaces, compared with those from patients with FH; there was an inverse association between dilated intercellular spaces and BI in the distal esophagus

  13. Germline mutation rates in families residing in high level natural radiation areas of Kerala coast in southwest India

    International Nuclear Information System (INIS)

    Das, Birajalaxmi; Ghosh, Anu; Ahmad, Shazia; Saini, DivyaIakshmi; Chauhan, P.S.; Seshadri, M.

    2010-01-01

    For this study, 200 nuclear families have been analyzed using over 40 mini- and microsatellite markers. Cord blood samples for the child and peripheral blood samples for the parent(s) were collected in EDTA vacuutainers from the hospital units located in High Level Natural Radiation Areas (HLNRA) and Normal Level Natural Radiation Areas (NLNRA). Both the parents of the newborn were exposed to the background dose. The families were grouped into four distinct dose groups - NLNRA group 5.00 mGy/year. An overall mutation rate of 2.08 X 10 -3 per cell per generation was observed for NLNRA and 2.12 X 10 -3 per cell per generation for HLNRA families. No radiation induced dose response was observed for the stratified groups. Thus, this study shows that mutation rates at mini- and microsatellites in the off springs of the parents living in the high background radiation areas of Kerala does not vary with radiation exposure. This is the first report to understand germline mutation rates at hypervariable loci in families residing in high level natural radiation areas of the world

  14. Petrography, Gamma Radiation Measurements and Dose Rate, Northeastern Um Ara Area, South Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    Moghazy, N.M.

    2016-01-01

    The northern part of Um Ara alkali feldspar micro granite has subjected to extensive post-magmatic metasomatic reworking resulting in development of amazonitized and albitized zones, reflecting K- and Na metasomatism leading to gross enrichment in U and Th towards the more evolved phases (e.g., albitized zones). Spectrometric survey data indicate that eU in Dokhan volcanics has the range of 2 to 42 ppm with an average value of 10 ppm and in monzogranites. It varies from 3 to 13 ppm with an average of 7 ppm while in alkali feldspar microgranites eU contents vary from 3 to 282 ppm with an average value of 30 ppm. The (eTh) contents in Dokhan volcanics ranges from 5-51 ppm with an average 18 ppm, in monzogranites their content was in the range of 11 to 47 ppm with an average value of 27 ppm where it ranges from 14 to 83 ppm with an average 46 ppm in alkali feldspar granite. The enhanced uranium content in altered zones was attributed to disseminated and fracture filling uranophane, autonite, in addition to other U and Th bearing minerals (such as columbite, zircon, monazite, xenotime and fluorite). Gamma-radiation dose rate and annual effective dose equivalents in mSv/y, Radium equivalent activity, external (H e x) and internal hazard index (H i n) and gamma activity index (Iγ) for all investigated samples were calculated to assess the potential radiation hazard for people living in dwellings made of the studied granites. Alkali feldspar granite activities would suggest that caution must be taken when using granites as building materials because they have radioactivity above the proposed acceptable level.

  15. Radiation Dose-rate Reduction Pattern in Well-differentiated Thyroid Cancer Treated with I-131.

    Science.gov (United States)

    Khan, Shahbaz Ahmad; Khan, Muhammad Saqib; Arif, Muhammad; Durr-e-Sabih; Rahim, Muhammad Kashif; Ahmad, Israr

    2015-07-01

    To determine the patterns of dose rate reduction in single and multiple radioiodine (I-131) therapies in cases of well differentiated thyroid cancer patients. Analytical series. Department of Nuclear Medicine and Radiation Physics, Multan Institute of Nuclear Medicine and Radiotherapy (MINAR), Multan, Pakistan, from December 2006 to December 2013. Ninety three patients (167 therapies) with well differentiated thyroid cancer treated with different doses of I-131 as an in-patient were inducted. Fifty four patients were given only single I-131 therapy dose ranging from 70 mCi (2590 MBq) to 150 mCi (5550 MBq). Thirty nine patients were treated with multiple I-131 radioisotope therapy doses ranging from 80 mCi (2960 MBq) to 250 mCi (9250 MBq). T-test was applied on the sample data showed statistically significant difference between the two groups with p-value (p < 0.01) less than 0.05 taken as significant. There were 68 females and 25 males with an age range of 15 to 80 years. Mean age of the patients were 36 years. Among the 93 cases of first time Radio Active Iodine (RAI) therapy, 59 cases (63%) were discharged after 48 hours. Among 39 patients who received RAI therapy second time or more, most were discharged earlier after achieving acceptable discharge dose rate i.e 25 µSv/hour; 2 out of 39 (5%) were discharged after 48 hours. In 58% patients, given single I-131 therapy dose, majority of these were discharged after 48 hours without any major complications. For well differentiated thyroid cancer patients, rapid dose rate reduction is seen in patients receiving second or subsequent radioiodine (RAI) therapy, as compared to first time receiving RAI therapy.

  16. Patterns of gas and liquid reflux during transient lower oesophageal sphincter relaxation: a study using intraluminal electrical impedance

    OpenAIRE

    Sifrim, D; Silny, J; Holloway, R; Janssens, J

    1999-01-01

    Background—Belching has been proposed as a major mechanism underlying acid gastro-oesophageal reflux in normal subjects. However, the presence of oesophageal gas has not been measured directly but only inferred from manometry. 
Aims—To investigate, using intraluminal electrical impedance, the patterns of gas and liquid reflux during transient lower oesophageal sphincter (LOS) relaxations, the main mechanism of acid reflux in normal subjects. 
Methods—Impedance changes ass...

  17. Analysis of radiation dose rate profile in the ambient Bhabha Atomic Research Centre, Trombay environment to evaluate radiation hazard

    International Nuclear Information System (INIS)

    Vikas; Anoj Kumar; Meena, T.R.; Vikas Kumar; Patra, R.P.; Patil, S.S.; Murali, S.; Singh, Rajvir; Pradeepkumar, K.S.

    2014-01-01

    Periodic radiological survey and its analysis are useful on a two way approach. First, it will be used to generate baseline dose profile that will be prominently important during any radiological emergency. Secondly, due to some unforeseen human acts if orphan/abandoned radioactive source were present across Bhabha Atomic Research Centre site, the same can be detected and retrieved from the incident location. Periodic radiation survey of Bhabha Atomic Research Centre, Trombay site primarily validate/serve as an indicator of integrity of the various safety measures at the different nuclear fuel cycle facilities and on the prevailing radiological status at the vicinity of the facilities at Bhabha Atomic Research Centre, Trombay site. Radiation dose profile as a quality information has been accumulated in the last five years. Analysis of data has led to the conclusion that there has been no increase in hazard over the years though the quantum of radioactivity processed at the various facilities has undergone wide increase and radiation hazard at the site continues to be very negligible. Nuclear fuel cycle activities at Bhabha Atomic Research Centre do not pose any excess radiation risk at the site

  18. Influence of clouds on the cosmic radiation dose rate on aircraft

    International Nuclear Information System (INIS)

    Pazianotto, Mauricio T.; Carlson, Brett V.; Federico, Claudio A.; Goncalez, Odair L.; Cortes-Giraldo, Miguel A.; Quesada, Jose Manuel M.; Palomo, Francisco R.; Pinto, Marcos Luiz de A.

    2014-01-01

    Flight missions were made in Brazilian territory in 2009 and 2011 with the aim of measuring the cosmic radiation dose rate incident on aircraft in the South Atlantic Magnetic Anomaly and to compare it with Monte Carlo simulations. During one of these flights, small fluctuations were observed in the vicinity of the aircraft with formation of Cumulonimbus clouds. Motivated by these observations, in this work, the authors investigated the relationship between the presence of clouds and the neutron flux and dose rate incident on aircraft using computational simulation. The Monte Carlo simulations were made using the MCNPX and Geant4 codes, considering the incident proton flux at the top of the atmosphere and its propagation and neutron production through several vertically arranged slabs, which were modelled according to the ISO specifications. The paper presents first-order calculation about the influence of Cumulonimbus clouds on the flux and dose rate due to cosmic neutrons in the atmosphere, at aircraft flight altitudes. The simulations show variations of the order of 5.5 % in the neutrons flux and 3.6 % of the dose rate due to the presence of the cloud. Such variations can extend up to ∼1.5 km from the edge of the cloud. The spectrum of neutrons within a cloud formation was observed undergo changes due to the neutron absorption and scattering processes with the water content inside the cloud. To accomplish these simulations, it is important to have a proper knowledge of the data libraries and nuclear models to be applied, since the simulation processes are strongly dependent on these factors. These results emphasise the importance of conducting more detailed studies on this topic, since the influence of clouds can change the dose and flux on aircraft overflying such formations, as well as could explain some of the fluctuations in the experimental dose rate data obtained in aircraft flights. Future studies should extend such simulations to different types of

  19. High rate of severe radiation dermatitis during radiation therapy with concurrent cetuximab in head and neck cancer: Results of a survey in EORTC institutes

    International Nuclear Information System (INIS)

    Giro, Christian; Berger, Bernhard; Boelke, Edwin; Ciernik, I. Frank; Duprez, Frederic; Locati, Laura; Maillard, Sophie; Ozsahin, Mahmut; Pfeffer, Raphael; Robertson, A. Gerry; Langendijk, Johannes A.; Budach, Wilfried

    2009-01-01

    Objective: Examination of the rate of grade III or grade IV radiation dermatitis during treatment of head and neck cancer (HNC) with radiotherapy (RT) and concurrent cetuximab in EORTC centres. Materials and method: A questionnaire was sent to all members of the EORTC Radiation Oncology Group and Head and Neck Group (111 institutions) to evaluate the widespread use of cetuximab and radiotherapy in HNC and to estimate the frequency of grades III and IV skin reactions in the radiation portals associated with this protocol. Co-morbidities, RT schedules and co-medications were also recorded. Results: We received responses from 28 institutions in 11 countries. A total of 125 HNC patients from 15 institutions were treated with cetuximab and concurrent RT. Information about the skin reactions was available from 71 patients. Of these 36 had no grade III/IV adverse effects in the RT field, 15 had a grade III and 20 had grade IV radiation dermatitis. No detectable relation of grades III and IV radiation dermatitis with co-morbidities such as liver insufficiency or renal dysfunction was found. Conclusion: According to the results of the questionnaire, grade III/IV radiation dermatitis is observed in 49% of HNC patients treated with cetuximab and concurrent RT. A systematic clinical monitoring of cutaneous side effects during RT plus cetuximab is advised to ensure the safety of this protocol

  20. The Effect of Dose Rate on Composite Durability When Exposed to a Simulated Long-Term Lunar Radiation Environment

    Science.gov (United States)

    Rojdev, Kristina; O'Rourke, Mary Jane; Hill, Charles; Nutt, Steven; Atwell, William

    2011-01-01

    Human exploration of space beyond low Earth orbit (LEO) requires a safe living and working environment for crew. Composite materials are one type of material being investigated by NASA as a multi-functional structural approach to habitats for long-term use in space or on planetary surfaces with limited magnetic fields and atmosphere. These materials provide high strength with the potential for decreased weight and increased radiation protection of crew and electronics when compared with conventional aluminum structures. However, these materials have not been evaluated in a harsh radiation environment, as would be experienced outside of LEO or on a planetary surface. Thus, NASA has been investigating the durability of select composite materials in a long-term radiation environment. Previously, NASA exposed composite samples to a simulated, accelerated 30-year radiation treatment and tensile stresses similar to those of a habitat pressure vessel. The results showed evidence of potential surface oxidation and enhanced cross-linking of the matrix. As a follow-on study, we performed the same accelerated exposure alongside an exposure with a decreased dose rate. The slower dose ]rate is comparable to a realistic scenario, although still accelerated. Strain measurements were collected during exposure and showed that with a fastdose rate, the strain decreased with time, but with a slow ]dose rate, the strain increased with time. After the radiation exposures, samples were characterized via tensile tests, flexure tests, Fourier Transform Infrared Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC). The results of these tests will be discussed.

  1. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    International Nuclear Information System (INIS)

    Levy, R.P.

    1991-01-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examining the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute γ-radiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. It was concluded that oligodendrocytes in irradiated cultures had significantly lower functional capacity than did unirradiated controls. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. At DIC 14, the group irradiated in a single fraction had significantly lower oligodendrocyte counts than any group given split doses; all irradiated cultures had marked depression of MBP synthesis, but to significant differences referable to time interval between doses. At DIC 21, cultures irradiated at intervals of 0 h to 2 h had similar oligodendrocyte counts to one another, but these counts were significantly lower than in cultures irradiated at intervals of 4 h to 6 h; MBP levels remained depressed at DIC 21 for all irradiated cultures. The oligodendrocyte response to dose rate (0.03 to 1.97 Gy/min) was evaluated at DIC 14 and DIC 21. Exposure at 0.03 Gy/min suppressed oligodendrocyte counts at DIC 21 less than did higher dose rates in 5-Gy irradiated cultures

  2. Influence of the rate of conversion of HT and HTO on projected radiation doses from release of molecular tritium

    International Nuclear Information System (INIS)

    Jacobs, D.G.; Easterly, C.E.; Phillips, J.E.

    1979-01-01

    Releases of tritium in the past have been largely in the form of tritiated water, and the projected radiation doses could be estimated by assuming tritium behaviour to parallel that of water. There is increasing interest in potential releases of tritium in the form of HT because of significant recent advances in fusion reactor research. Several recent studies have shown that bacteria containing the enzyme hydrogenase can catalyse the conversion of HT to HTO at rates several orders of magnitude faster than the rates measured in atmospheric systems. Rates of conversion in the soil have been combined with estimates of rates of permeation of HT into the soil and with global and local models depicting tritium transport and cycling. The results suggest that for the expected conversion rates, the impact on projected radiation doses should be relatively minor. (author)

  3. Quantitative analysis of biological responses to low dose-rate γ-radiation, including dose, irradiation time, and dose-rate

    International Nuclear Information System (INIS)

    Magae, J.; Furukawa, C.; Kawakami, Y.; Hoshi, Y.; Ogata, H.

    2003-01-01

    Full text: Because biological responses to radiation are complex processes dependent on irradiation time as well as total dose, it is necessary to include dose, dose-rate and irradiation time simultaneously to predict the risk of low dose-rate irradiation. In this study, we analyzed quantitative relationship among dose, irradiation time and dose-rate, using chromosomal breakage and proliferation inhibition of human cells. For evaluation of chromosome breakage we assessed micronuclei induced by radiation. U2OS cells, a human osteosarcoma cell line, were exposed to gamma-ray in irradiation room bearing 50,000 Ci 60 Co. After the irradiation, they were cultured for 24 h in the presence of cytochalasin B to block cytokinesis, cytoplasm and nucleus were stained with DAPI and propidium iodide, and the number of binuclear cells bearing micronuclei was determined by fluorescent microscopy. For proliferation inhibition, cells were cultured for 48 h after the irradiation and [3H] thymidine was pulsed for 4 h before harvesting. Dose-rate in the irradiation room was measured with photoluminescence dosimeter. While irradiation time less than 24 h did not affect dose-response curves for both biological responses, they were remarkably attenuated as exposure time increased to more than 7 days. These biological responses were dependent on dose-rate rather than dose when cells were irradiated for 30 days. Moreover, percentage of micronucleus-forming cells cultured continuously for more than 60 days at the constant dose-rate, was gradually decreased in spite of the total dose accumulation. These results suggest that biological responses at low dose-rate, are remarkably affected by exposure time, that they are dependent on dose-rate rather than total dose in the case of long-term irradiation, and that cells are getting resistant to radiation after the continuous irradiation for 2 months. It is necessary to include effect of irradiation time and dose-rate sufficiently to evaluate risk

  4. Transcutaneous Intraluminal Impedance Measurement for Minimally Invasive Monitoring of Gastric Motility: Validation in Acute Canine Models

    Directory of Open Access Journals (Sweden)

    Michael D. Poscente

    2014-01-01

    Full Text Available Transcutaneous intraluminal impedance measurement (TIIM is a new method to cutaneously measure gastric contractions by assessing the attenuation dynamics of a small oscillating voltage emitted by a battery-powered ingestible capsule retained in the stomach. In the present study, we investigated whether TIIM can reliably assess gastric motility in acute canine models. Methods. Eight mongrel dogs were randomly divided into 2 groups: half received an active TIIM pill and half received an identically sized sham capsule. After 24-hour fasting and transoral administration of the pill (active or sham, two force transducers (FT were sutured onto the antral serosa at laparotomy. After closure, three standard cutaneous electrodes were placed on the abdomen, registering the transluminally emitted voltage. Thirty-minute baseline recordings were followed by pharmacological induction of gastric contractions using neostigmine IV and another 30-minute recording. Normalized one-minute baseline and post-neostigmine gastric motility indices (GMIs were calculated and Pearson correlation coefficients (PCCs between cutaneous and FT GMIs were obtained. Statistically significant GMI PCCs were seen in both baseline and post-neostigmine states. There were no significant GMI PCCs in the sham capsule test. Further chronic animal studies of this novel long-term gastric motility measurement technique are needed before testing it on humans.

  5. Efficiency and safety of the intraluminal stent as a treatment malignant obstruction of the digestive tract

    International Nuclear Information System (INIS)

    Yu Xixiang; Si Tongguo; Pan Xiaohui; Yang Hui; Nan Yi; Huang Linfen; Feng Xiaofeng; Mao Aiwu

    2006-01-01

    Objective: To evaluate the efficiency and safety of intraluminal stent as a treatment of malignant obstruction of digestive tract and esophago-bronchial fistula. Methods: In total 71 patients suffered with malignant obstruction or esophago-bronchial fistula were treated with permanent nickel-titanium alloy, partially covered stents. All the procedures were performed under DSA guidance. Inserted via the oral anal access, the stents were placed at the sites of obstructions or the fistulas. Esophagogram or colonogram were done before and post the intervention. The clinical efficiency was assessed by function of swallowing or defecation in follow-up. Results: In 62 patients (96.9%), function of swallowing was restored after the stent was placed in upper digestive tract without drinking triggered coughing. Symptoms were immediately relieved after the stent was placed in sigmoid colon or rectum. Displacement of stents was seen in 2 cases (2.8%); restenosis in 2 (2.8%); hoarse voice was noted in 1 case (1.4%); intense thoracic pain was complained in 2 cases (2.8%); mild pain was noted in 12 cases (16.9%); and massive hemorrhage was complicated in 1 case (1.4%). All complications were successfully controlled after proper treatment. Conclusion: It is an effective, easy and safe method to treat malignant obstruction of digestive tract or esophago-bronchial fistula using partially covered nickel-titanium alloy stent. (authors)

  6. Hipotiroidismo congénito y diafragma intraluminal no fenestrado. Rara asociación

    Directory of Open Access Journals (Sweden)

    Nuvia Súarez García

    2014-02-01

    Full Text Available El hipotiroidismo congénito afecta a 1 de cada 3000 a 4000 neonatos y es una de las causas prevenibles de dificultades en el aprendizaje. Se presenta el caso de un recién nacido sexo masculino, que al nacer desarrolló síndrome de distréss respiratorio e intolerancia digestiva que progresó a la disfunción con distensión abdominal, además de signos dismórficos al examen físico. Se concluye el caso como hipotiroidismo congénito asociado a atresia duodenal por diafragma intraluminal no fenestrado. Se realizó intervención quirúrgica a las 46 horas de vida y en su posterior evolución presentó complicaciones mayores hasta fallecer. Se realizó una revisión actualizada sobre estas enfermedades en el período neonatal y se presentaron fotos del caso previo consentimiento familiar.

  7. The Relationship Between Pulsatile Flow Impingement and Intraluminal Thrombus Deposition in Abdominal Aortic Aneurysms.

    Science.gov (United States)

    Lozowy, Richard J; Kuhn, David C S; Ducas, Annie A; Boyd, April J

    2017-03-01

    Direct numerical simulations were performed on four patient-specific abdominal aortic aneurysm (AAA) geometries and the resulting pulsatile blood flow dynamics were compared to aneurysm shape and correlated with intraluminal thrombus (ILT) deposition. For three of the cases, turbulent vortex structures impinged/sheared along the anterior wall and along the posterior wall a zone of recirculating blood formed. Within the impingement region the AAA wall was devoid of ILT and remote to this region there was an accumulation of ILT. The high wall shear stress (WSS) caused by the impact of vortexes is thought to prevent the attachment of ILT. WSS from impingement is comparable to peak-systolic WSS in a normal-sized aorta and therefore may not damage the wall. Expansion occurred to a greater extent in the direction of jet impingement and the wall-normal force from the continuous impact of vortexes may contribute to expansion. It was shown that the impingement region has low oscillatory shear index (OSI) and recirculation zones can have either low or high OSI. No correlation could be identified between OSI and ILT deposition since different flow dynamics can have similar OSI values.

  8. 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

  9. 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

  10. Development of pixel readout integrated circuits for extreme rate and radiation

    CERN Multimedia

    Liberali, V; Rizzi, A; Re, V; Minuti, M; Pangaud, P; Barbero, M B; Pacher, L; Kluit, R; Hinchliffe, I; Manghisoni, M; Giubilato, P; Faccio, F; Pernegger, H; Krueger, H; Gensolen, F D; Bilei, G M; Da rocha rolo, M D; Prydderch, M L; Fanucci, L; Grillo, A A; Bellazzini, R; Palomo pinto, F R; Michelis, S; Huegging, F G; Kishishita, T; Marchiori, G; Christian, D C; Kaestli, H C; Meier, B; Andreazza, A; Key-charriere, M; Linssen, L; Dannheim, D; Conti, E; Hemperek, T; Menouni, M; Fougeron, D; Genat, J; Bomben, M; Marzocca, C; Demaria, N; Mazza, G; Van bakel, N A; Palla, F; Grippo, M T; Magazzu, G; Ratti, L; Abbaneo, D; Crescioli, F; Deptuch, G W; Neue, G; De robertis, G; Passeri, D; Placidi, P; Gromov, V; Morsani, F; Paccagnella, A; Christiansen, J; Dho, E; Wermes, N; Rymaszewski, P; Rozanov, A; Wang, A; Lipton, R J; Havranek, M; Neviani, A; Marconi, S; Karagounis, M; Godiot, S; Calderini, G; Seidel, S C; Horisberger, R P; Garcia-sciveres, M A; Stabile, A; Beccherle, R; Bacchetta, N

    The present hybrid pixel detectors in operation at the LHC represent a major achievement. They deployed a new technology on an unprecedented scale and their success firmly established pixel tracking as indispensable for future HEP experiments. However, extrapolation of hybrid pixel technology to the HL-LHC presents major challenges on several fronts. We propose a new RD collaboration specifically focused on the development of pixel readout Integrated Circuits (IC). The IC challenges include: smaller pixels to resolve tracks in boosted jets, much higher hit rates (1-2 GHz/cm$^{2}$), unprecedented radiation tolerance (10 MGy), much higher output bandwidth, and large IC format with low power consumption in order to instrument large areas while keeping the material budget low. We propose a collaboration to design the next generation of hybrid pixel readout chips to enable the ATLAS and CMS Phase 2 pixel upgrades. This does not imply that ATLAS and CMS must use the same exact pixel readout chip, as most of the dev...

  11. Radiation dose rates from adult patients receiving 131I therapy for thyrotoxicosis

    International Nuclear Information System (INIS)

    O'Doherty, M.J.; Kettle, A.G.; Eustance, C.N.P.; Mountford, P.J.; Coakley, A.J.

    1993-01-01

    Recommendations for restricting the exposure to radiation of members of the public coming into contact with thyrotoxic patients treated with 131 I are currently based on the activity retained by the patient, and not on the doses likely to be received by such individuals. In order to examine whether these current recommendations restrict these doses to less than the current annual limit of 5 mSv, and to identify the implications of a reduction in this limit to 1 mSv, measurements were made of the dose rates at distances of 0.1, 0.5 and 1.0 m from 60 patients just before they left the nuclear medicine department. These measurements were repeated 1, 3, 6, 8 and 10 days after administration for 30 patients, and the radioactivity in samples of saliva taken on each of these days and secreted in sweat over the first 24 h were also measured. Doses were estimated for administered activities of approximately 200-600 MBq, assuming appropriate values for the times and distances spent near other individuals while travelling, at work, at home and near to young children considered in three age groups. Periods of restriction were derived which would reduce these doses to 5 or 1 mSv. (Author)

  12. Study of compatibility of oligo-chitosan and ginkgo bilobal polyprenol influences on micronuclear rates and p53, gadd45 protein expression of radiated mice

    International Nuclear Information System (INIS)

    Guo Jianping; Wang Yongli; Wei Jinping; Yang Zhongtian; Liu Chunhui

    2012-01-01

    Study of compatibility of oligo-chitosan and ginkgo bilobal polyprenol (GP) influences on micronuclear rate and p53, gadd45 protein expression of radiated mice. Survival rate and survival time of 30-day-time of radiated mice was studied with the mixture of compatibility of oligo-chitosan and different density of GP. High survival rate of mixture density was screening. Another study on this mixture density was about micronuclear rates of marrow and p53, gadd45 protein of spleen after mice were radiated 12 h. The mixture of 300 mg/kg oligo-chitosan and 5 mg/kg GP could increase remarkably the survival rate and survival time of 30-day-time of radiated mice and degrade micronuclear rates and p53, gadd45 protein expression. Compatibility of oligo-chitosan and GP effectively raise the survival rate of radiated mice. It could proved initially that the mixture has the function of radiation protection. (authors)

  13. Normal appendix in adults: MDCT findings about the location, thickness and the presence or absence of intraluminal gas

    International Nuclear Information System (INIS)

    Oh, Kyoung Jin; Cho, June Sik; Shin, Kyung Sook; Kim, Ha Young; Lim, Sae Kyung; Ohm, Joon Young; Yoon, Chung Dae; Shin, Byung Seok

    2006-01-01

    We wanted to examine the usefulness of multi-detector CT (MDCT) with multiplanar reformations for evaluating the location, thickness and the presence or absence of intraluminal gas in the normal appendix of adults. From December 2004 to June 2005, we evaluated normal appendices in 427 consecutive adult patients who were scanned with 16-slice MDCT. All these patients had no clinical findings of appendicitis. There were 251 men and 176 women. The age range was 19-84 years (mean age: 55 years). The contrast-enhanced MDCT scans during the portal phase were obtained with 0.75 mm detector collimation and they were reviewed with using the multiplanar reconstruction images (3 mm section thickness). The MDCT images of normal appendices on a PACS monitor were retrospectively analyzed. We analyzed the location, thickness and the presence or absence of intraluminal gas by consensus of two abdominal radiologists. The positions of normal appendices were classified as type I (postileal and medial paracecal), type II (subcecal), type III (retrocecal and retrocolic or laterocolic), type IV (preileal and medical colic) and type V (lower pelvic cavity). The five types of appendiceal locations were as follows: type I (n = 187; 44%), type II (n 78; 18%), type III (n = 92, 22%), type IV (n = 39; 9%) and type V (n = 31; 7%). The appendiceal tips in 29 cases (7%) were unusually located in the right subhepatic space, the small bowel mesentery and the right adnexa. The mean thickness of 427 appendices was 5.8 ± 0.9 mm (range: 3.8-9.2 mm). The appendiceal mean thickness was 5.9 ± 0.9 mm in men and 5.7 ± 0.9 mm in women (ρ < 0.05). 384 (90%) of 427 appendices had intraluminal gas and 43 (10%) had no intraluminal gas, and their mean thickness was 5.9 mm (range: 3.8-9.2 mm) and 5.3 mm (3.8-7.3 mm), respectively (ρ < 0.05). MDCT with multiplanar reformations was useful for evaluating the location, thickness and the presence or absence of intraluminal gas in normal appendix of adults. These

  14. Mathematical model for evaluation of dose-rate effect on biological responses to low dose γ-radiation

    International Nuclear Information System (INIS)

    Ogata, H.; Kawakami, Y.; Magae, J.

    2003-01-01

    Full text: To evaluate quantitative dose-response relationship on the biological response to radiation, it is necessary to consider a model including cumulative dose, dose-rate and irradiation time. In this study, we measured micronucleus formation and [ 3 H] thymidine uptake in human cells as indices of biological response to gamma radiation, and analyzed mathematically and statistically the data for quantitative evaluation of radiation risk at low dose/low dose-rate. Effective dose (ED x ) was mathematically estimated by fitting a general function of logistic model to the dose-response relationship. Assuming that biological response depends on not only cumulative dose but also dose-rate and irradiation time, a multiple logistic function was applied to express the relationship of the three variables. Moreover, to estimate the effect of radiation at very low dose, we proposed a modified exponential model. From the results of fitting curves to the inhibition of [ 3 H] thymidine uptake and micronucleus formation, it was obvious that ED 50 in proportion of inhibition of [ 3 H] thymidine uptake increased with longer irradiation time. As for the micronuclei, ED 30 also increased with longer irradiation times. These results suggest that the biological response depends on not only total dose but also irradiation time. The estimated response surface using the three variables showed that the biological response declined sharply when the dose-rate was less than 0.01 Gy/h. These results suggest that the response does not depend on total cumulative dose at very low dose-rates. Further, to investigate the effect of dose-rate within a wider range, we analyzed the relationship between ED x and dose-rate. Fitted curves indicated that ED x increased sharply when dose-rate was less than 10 -2 Gy/h. The increase of ED x signifies the decline of the response or the risk and suggests that the risk approaches to 0 at infinitely low dose-rate

  15. Expression of cytoskeletal and matrix genes following exposure to ionizing radiation: Dose-rate effects and protein synthesis requirements

    International Nuclear Information System (INIS)

    Woloschak, G.E.

    1994-01-01

    Experiments were designed to examine the effects Of radiation dose-rate and of the protein synthesis inhibitor cycloheximide on expression of cytoskeletal elements (γ- and β-actin and α-tubulin) and matrix elements (fibronectin) in Syrian hamster embryo cells. Past work from our laboratory had already demonstrated optimum time points and doses for examination of radiation effects on accumulation of specific transcripts. Our results here demonstrated little effect of dose-rate for JANUS fission spectrum neutrons when comparing expression of either α-tubulin or fibronectin genes. Past work had already documented similar results for expression of actin transcripts. Effects of cycloheximide revealed that cycloheximide repressed accumulation of α-tubulin following exposure to high dose-rate neutrons or γ rays; this did not occur following similar low dose-rate exposure. (2) Cycloheximide did not affect accumulation of MRNA for actin genes; and that cycloheximide abrogated the moderate induction of fibronectin-mRNA which occurred following exposure to γ rays and high dose-rate neutrons. These results suggest a role for labile proteins in the maintenance of α-tubulin and fibronectin MRNA accumulation following exposure to ionizing radiation. in addition, they suggest that the cellular/molecular response to low dose-rate neutrons may be different from the response to high dose-rate neutrons

  16. Expression of cytoskeletal and matrix genes following exposure to ionizing radiation: Dose-rate effects and protein synthesis requirements

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Felcher, P.; Chang-Liu, Chin-Mei

    1992-01-01

    Experiments were designed to examine the effects of radiation dose-rate and of the protein synthesis inhibitor cycloheximide on expression of cytoskeletal elements (γ- and β-actin and α-tubulin) and matrix elements (fibronectin) in Syrian hamster embryo cells. Past work from our laboratory had already demonstrated optimum time points and doses for examination of radiation effects on accumulation of specific transcripts. Our results here demonstrated little effect of dose-rate for JANUS fission spectrum neutrons when comparing expression of either α-tubulin or fibronectin genes. Past work had already documented similar results for expression of actin transcripts. Effects of cycloheximide, however, revealed several interesting and novel findings: (1) Cycloheximide repressed accumulation of α-tubulin following exposure to high dose-rate neutrons or γ rays; this did not occur following similar low dose-rate exposure (2) Cycloheximide did not affect accumulation of mRNA for actin genes. Cycloheximide abrogated the moderate induction of fibronectin-mRNA which occurred following exposure to γ rays and high dose-rate neutrons. These results suggest a role for labile proteins in the maintenance of α-tubulin and fibronectin mRNA accumulation following exposure to ionizing radiation. In addition, they suggest that the cellular/molecular response to low dose-rate neutrons may be different from the response to high dose-rate neutrons

  17. Chronic action of gamma-radiation on growing cell population of the yeast Saccharomyces cerevisiae at various dose rates

    International Nuclear Information System (INIS)

    Zyuzikov, N.A.; Petin, V.G.

    1996-01-01

    Experimental data on the processes of division and death of haploid and diploid yeast Saccharomyces cerevisiae of wild type and of their radiosensitive mutants exposed under optimal for reproduction conditions to chronic gamma-radiation at various dose rates are presented. It is shown that the dependence of the integral division/death process in time was exponential for all the studied strains. With dose rate increasing, the duration of the lag period and the probability of cell inactivation increased, while the multiplication rate decreased. These processes, for equal dose rates, were more expressed for the radiosensitive mutants

  18. Radiation graft copolymerization of styrene with m/e and styrene with acrylic acid at highthyl methacryl dose rate

    International Nuclear Information System (INIS)

    Aliev, R.Eh.; Kabanov, B.Ya.

    1984-01-01

    Comparative investigation of radiation graft copolymerization of styrene with methyl methacrylate (MMA) and styrene with acrylic acid (AA) is carried out at considerably differing radiation dose rates. The monomer mixture was grafted to PE low density films at dose rates of 0.16, 0.25 Gy/s (1 MeV electron acceleration). The value of graft was 3-6 and 5-10%, respectively, for the styrene-MMA and styrene-AA systems. An essential difference in the dependences of the formed copolymer composition on initial monomer mixture composition is noticed. Difference in composition of graft polymers prepared at different dose rates is less for the systems with AA, than for systems with MMA. It is shown that at high dose rates in difference with low ones not only radical graft copolymerization of the styrene mixture with AA takes place, but a contribution of the graft styrene polymerization according to cation mechanism as well

  19. Effect Analysis on the Radiation Dose Rate of Nagasaki Atomic Bomb Survivors by Atmospheric Condition

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Ji Sun; Kim, Jong Kyung [Hanyang University, Seoul (Korea, Republic of); Shin, Chang Ho [Innovative Technology Center for Radiation Safety, Seoul (Korea, Republic of); Kim, Do Heon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    The Dosimetry System 2002 (DS02) had been established to evaluate the radiation doses for the atomic bomb survivors in Hiroshima and Nagasaki. The radiation effects of neutrons and gamma-rays emitted from the atomic bombs detonated at both cities were analyzed, and two types of radiation transport codes (i.e., MCNP4C and DORT) were employed in their studies. It was specifically investigated for contribution of each type of radiations to total dose. However, it is insufficient to examine the effects by various environmental factors such as weather conditions, because their calculations were only performed under certain condition at the times of the bombings. In addition, the scope of them does not include acute radiation injury of the atomic bomb survivors in spite of important information for investigating hazard of unexpected radiation accident. Therefore, this study analyzed the contribution of primary and secondary effects (i.e., skyshine and groundshine) of neutrons emitted from the Nagasaki atomic bomb. These analyses were performed through a series of radiation transport calculations by using MCNPX 2.6.0 code with variations of atmospheric density. The acute radiation injury by prompt neutrons was also evaluated as a function of distance from the hypocenter, where hypocenter is the point on the ground directly beneath the epicenter which is the burst point of the bomb in air

  20. Obligatory Role of Intraluminal O2− in Acute Endothelin-1 and Angiotensin II Signaling to Mediate Endothelial Dysfunction and MAPK Activation in Guinea-Pig Hearts

    Directory of Open Access Journals (Sweden)

    Emilia Wojtera

    2014-10-01

    Full Text Available We hypothesized that, due to a cross-talk between cytoplasmic O2−-sources and intraluminally expressed xanthine oxidase (XO, intraluminal O2− is instrumental in mediating intraluminal (endothelial dysfunction and cytosolic (p38 and ERK1/2 MAPKs phosphorylation manifestations of vascular oxidative stress induced by endothelin-1 (ET-1 and angiotensin II (AT-II. Isolated guinea-pig hearts were subjected to 10-min agonist perfusion causing a burst of an intraluminal O2−. ET-1 antagonist, tezosentan, attenuated AT-II-mediated O2−, indicating its partial ET-1 mediation. ET-1 and Ang-T (AT-II + tezosentan triggered intraluminal O2−, endothelial dysfunction, MAPKs and p47phox phosphorylation, and NADPH oxidase (Nox and XO activation. These effects were: (i prevented by blocking PKC (chelerythrine, Nox (apocynin, mitochondrial ATP-dependent K+ channel (5-HD, complex II (TTFA, and XO (allopurinol; (ii mimicked by the activation of Nox (NADH; and mitochondria (diazoxide, 3-NPA and (iii the effects by NADH were prevented by 5-HD, TTFA and chelerythrine, and those by diazoxide and 3-NPA by apocynin and chelerythrine, suggesting that the agonists coactivate Nox and mitochondria, which further amplify their activity via PKC. The effects by ET-1, Ang-T, NADH, diazoxide, and 3-NPA were opposed by blocking intraluminal O2− (SOD and XO, and were mimicked by XO activation (hypoxanthine. Apocynin, TTFA, chelerythrine, and SOD opposed the effects by hypoxanthine. In conclusion, oxidative stress by agonists involves cellular inside-out and outside-in signaling in which Nox-mitochondria-PKC system and XO mutually maintain their activities via the intraluminal O2−.

  1. Comparison of Recanalization and In-Stent Stenosis Between the Low-Profile Visualized Intraluminal Support Stent and Enterprise Stent-Assisted Coiling for 254 Intracranial Aneurysms.

    Science.gov (United States)

    Feng, Xin; Qian, Zenghui; Liu, Peng; Zhang, Baorui; Wang, Luyao; Guo, Erkang; Wen, Xiaolong; Xu, Wenjuan; Jiang, Chuhan; Wu, Zhongxue; Li, Youxiang; Liu, Aihua

    2018-01-01

    To compare the rates of recanalization and in-stent stenosis between the Enterprise (EP) and low-profile visualized intraluminal support (LVIS) stent deployments for intracranial aneurysms (IAs), and the factors associated therein. Between June 2014 and July 2016, 142 patients with a total of 161 IAs were treated by LVIS stent-assisted coiling and 111 patients with a total of 142 IAs were treated by EP stent-assisted coiling at our institution. Procedure-related complications, angiographic follow-up results, and clinical outcomes were analyzed statistically. The rates of initially complete and near-complete IA occlusion immediately after the procedure were similar in the LVIS and EP groups (94.3% vs. 89.9%; P = 0.275). On follow-up, complete and near-complete occlusion rates and recanalization rates were also similar in the 2 groups (96.6% vs. 92.1%; P =0.330 and 8.0% vs. 13.5%; P = 0.245, respectively). On logistic regression analysis, a higher size ratio (SR) was significantly associated with the recanalization of aneurysms in the EP group, but not in the LVIS group. The rate of moderate to severe in-stent stenosis was lower in the LVIS group (10.2%) than in the EP group (16.8%), but the difference was not statistically significant (P = 0.198). Our data show acceptable rates of complete and near-complete occlusion with both the LVIS and EP stents. LVIS stents were associated with lower rates of recanalization and in-stent stenosis, but the difference was not significant. Higher SR (≥2) was a significant predictor of recanalization in IAs treated with EP stents, but not in those treated with LVIS stents. Copyright © 2017. Published by Elsevier Inc.

  2. Discussion about the range of natural radiation exposure rate found in dwelling-houses in the Federal Republic of Germany and in Poland

    International Nuclear Information System (INIS)

    Schmier, H.; Pensko, J.; Wicke, A.

    1982-01-01

    In this paper the range of natural radiation exposure rate found in dwelling-houses is discussed. The source of this exposure are natural radionuclides 40 K, 226 Ra, 232 Th and their decay products widely distributed in soil and in building materials. The resulting whole body dose equivalent rate of gamma radiation is compared to the effective dose equivalent rate of alpha radiation originating from 222 Rn diffusing out of building materials and decaying to alpha emitting short living daughters. (Author) [de

  3. Absorbed dose to mice in prolonged irradiation by low-dose rate ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shiragai, Akihiro [National Inst. of Radiological Sciences, Chiba (Japan); Saitou, Mikio; Kudo, Iwao [and others

    2000-07-01

    In this paper, the dose absorbed by mice was evaluated as a preliminary study of the late effects of prolonged continuous irradiation of mice with low-dose rate ionizing radiation. Eight-week-old male and female SPF C3H/HeN mice in three irradiation rooms were exposed to irradiation at 8000, 400, and 20 mGy, respectively, using a {sup 137}Cs {gamma}-source. Nine racks were arranged in a circle approximately 2.5 m from the source in each room, and 10 cages were arranged on the 4 shelves of each rack. Dose distributions, such as in air at the source level, in the three rooms were estimated by using ionization chambers, and the absorbed dose distributions in the room and relative dose distributions in the cages in relation to the distance of the cage center were examined. The mean abdomen doses of the mice measured by TLD were compared with the absorbed doses in the cages. The absorbed dose distributions showed not only inverse-inverse-square-law behavior with distance from the source, but geometric symmetry in every room. The inherent scattering and absorption in each room are responsible for such behavior and asymmetry. Comparison of relative dose distributions revealed cage positions that are not suitable for experiments with high precision doses, but all positions can be used for prolonged continuous irradiation experiments if the position of the cages is rotated regularly. The mean abdomen doses of the mice were similar in each cage. The mean abdomen doses of the mice and the absorbed doses in a cage were almost the same in all cages. Except for errors concerning the positions of the racks and cages, the uncertainties in the exposure doses were estimated to be about {+-}12% for 8000 mGy group, 17% for 400 mGy group, and 35% for 20 mGy group. (K.H.)

  4. Radiative Rates for Forbidden Transitions in Doubly-Ionized Fe-Peak Elements

    Science.gov (United States)

    Fivet, Vanessa; Quinet, P.; Bautista, M.

    2012-05-01

    Accurate and reliable atomic data for lowly-ionized Fe-peak species (Sc, Ti, V, Cr, Mn, Fe, Co, Ni and Cu) are of paramount importance for the analysis of the high resolution astrophysical spectra currently available. The third spectra of several iron group elements have been observed in different galactic sources like Herbig-Haro objects in the Orion Nebula [1] and stars like Eta Carinae [2]. However, forbidden transitions between low-lying metastable levels of doubly-ionized iron-peak ions have been very little investigated so far and radiative rates for those lines remain sparse or inexistent. We are carrying out a systematic study of the electronic structure of doubly-ionized iron-peak elements. The magnetic dipole (M1) and electric quadrupole (E2) transition probabilities are computed using the pseudo-relativistic Hartree-Fock (HFR) code of Cowan [3] and the central Thomas-Fermi-Dirac potential approximation implemented in AUTOSTRUCTURE [4]. This multi-platform approach allows for consistency checks and intercomparison and has proven very successful in the study of the complex Fe-peak species where many different effects contribute [5]. References [1] A. Mesa-Delgado et al., MNRAS 395 (2009) 855 [2] S. Johansson et al., A&A 361 (2000) 977 [3] R.D. Cowan, The Theory of Atomic Structure and Spectra, Berkeley: Univ. California Press (1981) [4] N.R. Badnell, J. Phys. B: At. Mol. Opt. Phys. 30 (1997) 1 [5] M. Bautista et al., ApJ 718 (2010) L189

  5. Effect of solar radiation on the lipid characterization of biomass cultivated in high-rate algal ponds using domestic sewage.

    Science.gov (United States)

    Assemany, Paula Peixoto; Calijuri, Maria Lúcia; Santiago, Anibal da Fonseca; do Couto, Eduardo de Aguiar; Leite, Mauricio de Oliveira; Sierra, Jose Jovanny Bermudez

    2014-01-01

    The objective of this paper is to compare the lipid content and composition ofbiomass produced by a consortium of microalgae and bacteria, cultivated under different solar radiation intensities and tropical conditions in pilot-scale high-rate ponds (HRPs) using domestic sewage as culture medium. The treatment system consisted of an upflow anaerobic sludge blanket reactor followed by UV disinfection and six HRPs covered with shading screens that blocked 9%, 18%, 30%, 60% and 80% of the solar radiation. The total lipid content does not vary significantly among the units, showing a medium value of 9.5%. The results show that blocking over 30% of the solar radiation has a negative effect on the lipid productivity. The units with no shading and with 30% and 60% of solar radiation blocking have statistically significant lipid productivities, varying from 0.92 to 0.96 gm(-2) day(-1). Besides radiation, other variables such as volatile suspended solids and chlorophyll-a are able to explain the lipid accumulation. The lipid profile has a predominance of C16, C18:1 and C18:3 acids. The unsaturation of fatty acids increases with the reduction in solar radiation. On the other hand, the effect of polyunsaturation is not observed, which is probably due to the presence of a complex and diverse biomass.

  6. Computer simulation of radiation damage in NaCl using a kinetic rate reaction model

    International Nuclear Information System (INIS)

    Soppe, W.J.

    1993-01-01

    Sodium chloride and other alkali halides are known to be very susceptible to radiation damage in the halogen sublattice when exposed to ionizing radiation. The formation of radiation damage in NaCl has generated interest because of the relevance of this damage to the disposal of radioactive waste in rock salt formations. In order to estimate the long-term behaviour of a rock salt repository, an accurate theory describing the major processes of radiation damage in NaCl is required. The model presented in this paper is an extended version of the Jain-Lidiard model; its extensions comprise the effect of impurities and the colloid nucleation stage on the formation of radiation damage. The new model has been tested against various experimental data obtained from the literature and accounts for several well known aspects of radiation damage in alkali halides which were not covered by the original Jain-Lidiard model. The new model thus may be expected to provide more reliable predictions for the build-up of radiation damage in a rock salt nuclear waste repository. (Author)

  7. A study of intraluminal flow in patients with aortic disease by cine magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ohnishi, Shusaku; Fukui, Sugao; Kusuoka, Hideo; Kitabatake, Akira; Kamada, Takenobu.

    1990-01-01

    To evaluate the usefulness of cine magnetic resonance (MR) imaging in the diagnosis of aortic disease, we applied cine MR sequences with conventional spin echo (SE) sequence to 15 patients with aortic aneurysm and 5 patients with aortic dissection. ECG gated multi slice SE images (single echo) were obtained in transverse plane and the planes along the long axis of aorta. TE of SE sequence ranged from 15 to 32 msec. Cine MR images were obtained in 17 frames, where TR ranged from 30 to 60 msec and TE from 10 to 22 msec. We got these results as follows. For aortic aneurysm, SE images showed aneurysmal dilatation in thoracic aorta in 9 cases, and in abdominal aorta in 6 cases. Cine MR images showed us the intraluminal flow with high signal intensity. We could differentiate the slow flow image from mural thrombus using SE and cine MR sequences in the same plane. We could evaluate the dynamic flow image within a cavity of aneurysm and in in-flow and out-flow portions of aorta by cine MR imaging. For aortic dissection, SE images delineated the intimal tear and two separated lumens in all cases. We could obtain flow images within true and false lumen by cine MR imaging. The signal intensity within true lumen was higher than that within false lumen. It seemed to be due to the difference of flow velocity and the turbulence within false lumen. Entry to false lumen was seen as the interruption of dissected intima on SE images. Cine MR images clearly depicted the blood flow communication between two lumens through the entry. In 3 of 5 cases the blood flow through the entry was seen in both directions, from true to false lumen in systole and inversely in diastole. Thus, cine MR imaging will add the useful hemodynamic information in the diagnosis of aortic disease by conventional MR imaging. (author)

  8. Computed tomography angiography intraluminal filling defect is predictive of internal carotid artery free-floating thrombus

    Energy Technology Data Exchange (ETDEWEB)

    Jaberi, A.; Lum, C.; Stefanski, P.; Iancu, D. [University of Ottawa, Faculty of Medicine, Ottawa, Ontario (Canada); The Ottawa Hospital, Department of Radiology, Neuroradiology Section, Ottawa, Ontario (Canada); Thornhill, R. [Neurosciences and Clinical Epidemiology Program/Methods Centre, Ottawa Hospital Research Institute, Ottawa, Ontario (Canada); The Ottawa Hospital, Department of Radiology, Neuroradiology Section, Ottawa, Ontario (Canada); Petrcich, W. [Neurosciences and Clinical Epidemiology Program/Methods Centre, Ottawa Hospital Research Institute, Ottawa, Ontario (Canada); Momoli, F. [Children' s Hospital of Eastern Ontario Research Institute, Ottawa, Ontario (Canada); University of Ottawa, Department of Epidemiology and Community Medicine, Ottawa, Ontario (Canada); Torres, C.; Dowlatshahi, D. [University of Ottawa, Faculty of Medicine, Ottawa, Ontario (Canada); University of Ottawa, Division of Neurology, Department of Medicine, Ottawa, Ontario (Canada)

    2014-01-15

    Filling defects at the internal carotid artery (ICA) origin in the work-up of stroke or transient ischemic attack may be an ulcerated plaque or free-floating thrombus (FFT). This may be challenging to distinguish, as they can appear morphologically similar. This is an important distinction as FFT can potentially embolize distally, and its management differs. We describe a series of patients with suspected FFT and evaluate its imaging appearance, clinical features, and evolution with therapy. Between 2008 and 2013, we prospectively collected consecutive patients with proximal ICA filling defects in the axial plane surrounded by contrast on CT/MR angiography. We defined FFT as a filling defect that resolved on follow-up imaging. We assessed the cranial-caudal dimension of the filling defect and receiver operating characteristics to identify clinical and radiological variables that distinguished FFT from complex ulcerated plaque. Intraluminal filling defects were identified in 32 patients. Filling defects and resolved or decreased in 25 patients (78 %) and felt to be FFT; there was no change in 7 (22 %). Resolved defects and those that decreased in size extended more cranially than those that remained unchanged: 7.3 mm (4.2-15.9) versus 3.1 mm (2.7-3.7; p = 0.0038). Receiver operating characteristic analysis established a threshold of 3.8 mm (filling defect length), sensitivity of 88 %, specificity of 86 %, and area under the curve of 0.86 (p < 0.0001) for distinguishing FFT from plaque. Filling defects in the proximal ICA extending cranially >3.8 mm were more likely to be FFT than complex ulcerated plaque. Further studies evaluating filling defect length as a predictor for FFT are warranted. (orig.)

  9. On the Impact of Intraluminal Thrombus Mechanical Behavior in AAA Passive Mechanics.

    Science.gov (United States)

    Riveros, Fabián; Martufi, Giampaolo; Gasser, T Christian; Rodriguez-Matas, Jose F

    2015-09-01

    Intraluminal thrombus (ILT) is a pseudo-tissue that develops from coagulated blood, and is found in most abdominal aortic aneurysms (AAAs) of clinically relevant size. A number of studies have suggested that ILT mechanical characteristics may be related to AAA risk of rupture, even though there is still great controversy in this regard. ILT is isotropic and inhomogeneous and may appear as a soft (single-layered) or stiff (multilayered fibrotic) tissue. This paper aims to investigate how ILT constitution and topology influence the magnitude and location of peak wall stress (PWS). In total 21 patient-specific AAAs (diameter 4.2-5.4 cm) were reconstructed from computer tomography images and biomechanically analyzed using state-of-the-art modeling assumptions. Results indicated that PWS correlated stronger with ILT volume (ρ = 0.44, p = 0.05) and minimum thickness of ILT layer (ρ = 0.73, p = 0.001) than with maximum AAA diameter (ρ = 0.05, p = 0.82). On average PWS was 20% (SD 12%) higher for FE models that used soft instead of stiff ILT models (p AAA diameter and was independent from ILT stiffness. In addition, ILT heterogeneity, i.e., the spatial composition of soft and stiff thrombus tissue, can considerably influence stress in the AAA wall. The present study is limited to identification of influential biomechanical factors, and how its findings translate to an AAA rupture risk assessment remains to be explored by clinical studies.

  10. Persistent Intraluminal Pressure After Endovascular Stent Grafting for Type B Aortic Dissection.

    Science.gov (United States)

    Qing, K-X; Chan, Y-C; Ting, A C W; Cheng, S W K

    2016-05-01

    Despite technically successful thoracic endovascular stent graft repair (TEVAR) in patients with Stanford Type B aortic dissection (TBAD), long-term follow up studies have shown that the false lumen may continue to dilate. The aim of this study was to analyze the possible mechanisms leading to such changes from a hemodynamic perspective. Twenty-eight ex vivo fresh porcine TBAD models (Mo A: 10; Model B: 12; Model C: 6) were established to simulate three clinical situations: Model A with patent false lumen (pre-TEVAR); Model B with distal re-entry only (post-TEVAR), and Model C with thrombus filling in the false lumen and a distal re-entry (chronic stage of post-TEVAR). Synchronous pressure waveforms were taken from both the true and the false lumen. True lumen and false lumen pressure differences were calculated for each model as four indices: systolic index (SI), diastolic index (DI), mean pressure index (MPI) and area under curve index (AUCI). These indices were compared between the three models. False lumen pressure and corresponding pressure-accumulating effects were significantly higher in Model A than in Model C: SI (99.9% vs. 189.4%; p area under curve (AUC) in Model C was merely lowered by 20% compared with its true lumen (67.5 mmHg vs. 85.2 mmHg). The false lumen pressure remained unchanged in the non-thrombosed segment with patent blood flow after the primary entry tear sealed. Intraluminal pressure reduction in the thrombosed false lumen was significant. However, nearly 80% of the pressure remained in the thrombosed false lumen. If this high intra-thrombus pressure persists, it may contribute to delayed aneurysmal formation after endovascular treatment. Copyright © 2016 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  11. Intraesophageal pressure recording improves the detection of cough during multichannel intraluminal impedance testing in children.

    Science.gov (United States)

    Rosen, Rachel; Amirault, Janine; Giligan, Emily; Khatwa, Umakanth; Nurko, Samuel

    2014-01-01

    One of the primary reasons for referral for reflux testing is to correlate reflux events with symptoms such as cough. Adult studies have suggested that symptom recording is flawed and pediatricians feel this is an even more significant problem because there may be errors in both parental and patient reports. We hypothesize that intraesophageal pressure recording (IEPR) provides an objective method to identify coughs during reflux testing in children. We recruited 20 children undergoing multichannel intraluminal impedance with pH (pH-MII) testing for the evaluation of cough. We placed simultaneous intraesophageal pressure and pH-MII catheters. Tracings were blindly scored by 2 observers without knowledge of patient/parent symptom report. After the blinded scoring, patient/parent report of symptoms was recorded. Ninety-four percent of all coughs were detected by IEPR and only 48% of all coughs were reported by patients/parents. The mean time from the IEPR cough to the patient/parent cough was 11±16 seconds. Using IEPR as the criterion standard for the detection of cough, the sensitivity of patient report for the detection of cough is 46%. Using varying symptom windows because of the increased precision of IEPR, the number of patients with a positive symptom index could be reduced from 30% to 0%, preventing children from being falsely categorized as having reflux-related lung disease. Parental and patient symptom recording in children is inadequate for making the diagnosis of reflux-related lung disease. If patients undergo pH-MII testing for reflux-related cough, IEPR should become the new standard by which to correlate reflux with cough.

  12. The importance of applicator design for intraluminal brachytherapy of rectal cancer

    International Nuclear Information System (INIS)

    Hansen, Johnny Witterseh; Jakobsen, Anders

    2006-01-01

    An important aspect of designing an applicator for radiation treatment of rectal cancer is the ability to minimize dose to the mucosa and noninvolved parts of the rectum wall. For this reason we investigated a construction of a flexible multichannel applicator with several channels placed along the periphery of a cylinder and a construction of a rigid cylinder with a central channel and interchangeable shields. Calculations of the dose gradient, dose homogeneity in the tumor, and shielding ability were performed for the two applicators in question. Furthermore, the influence on dose distribution around a flexible multichannel applicator from an unintended off-axis positioning of the source inside a bent channel was investigated by film measurements on a single bent catheter. Calculations showed that a single-channel applicator with interchangeable shields yields a higher degree of shielding and has a better dose homogeneity in the tumor volume than that of a multichannel applicator. A single-channel applicator with interchangeable shields was manufactured, and the influence of different size of shield angle on dose rate in front of and behind the shields was measured. While dose rate in front of the shield and shielding ability are closely independent of the size of the shield angle when measured 1 cm from the applicator surface, dose rate in more distant volumes will to some extent be influenced by shield angle due to volume scatter conditions

  13. Parametrization of the average ionization and radiative cooling rates of carbon plasmas in a wide range of density and temperature

    International Nuclear Information System (INIS)

    Gil, J.M.; Rodriguez, R.; Florido, R.; Rubiano, J.G.; Mendoza, M.A.; Nuez, A. de la; Espinosa, G.; Martel, P.; Minguez, E.

    2013-01-01

    In this work we present an analysis of the influence of the thermodynamic regime on the monochromatic emissivity, the radiative power loss and the radiative cooling rate for optically thin carbon plasmas over a wide range of electron temperature and density assuming steady state situations. Furthermore, we propose analytical expressions depending on the electron density and temperature for the average ionization and cooling rate based on polynomial fittings which are valid for the whole range of plasma conditions considered in this work. -- Highlights: ► We compute the average ionization, cooling rates and emissivities of carbon plasmas. ► We compare LTE and NLTE calculations of these magnitudes. ► We perform a parametrization of these magnitudes in a wide range of plasma conditions. ► We provide information about where LTE regime assumption is accurate

  14. Verification of absorbed dose rates in reference beta radiation fields: measurements with an extrapolation chamber and radiochromic film

    Energy Technology Data Exchange (ETDEWEB)

    Reynaldo, S. R. [Development Centre of Nuclear Technology, Posgraduate Course in Science and Technology of Radiations, Minerals and Materials / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Benavente C, J. A.; Da Silva, T. A., E-mail: sirr@cdtn.br [Development Centre of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Beta Secondary Standard 2 (Bss 2) provides beta radiation fields with certified values of absorbed dose to tissue and the derived operational radiation protection quantities. As part of the quality assurance, metrology laboratories are required to verify the reliability of the Bss-2 system by performing additional verification measurements. In the CDTN Calibration Laboratory, the absorbed dose rates and their angular variation in the {sup 90}Sr/{sup 90}Y and {sup 85}Kr beta radiation fields were studied. Measurements were done with a 23392 model PTW extrapolation chamber and with Gafchromic radiochromic films on a PMMA slab phantom. In comparison to the certificate values provided by the Bss-2, absorbed dose rates measured with the extrapolation chamber differed from -1.4 to 2.9% for the {sup 90}Sr/{sup 90}Y and -0.3% for the {sup 85}Kr fields; their angular variation showed differences lower than 2% for incidence angles up to 40-degrees and it reached 11% for higher angles, when compared to ISO values. Measurements with the radiochromic film showed an asymmetry of the radiation field that is caused by a misalignment. Differences between the angular variations of absorbed dose rates determined by both dosimetry systems suggested that some correction factors for the extrapolation chamber that were not considered should be determined. (Author)

  15. Shutdown dose rates at ITER equatorial ports considering radiation cross-talk from torus cryopump lower port

    Energy Technology Data Exchange (ETDEWEB)

    Juárez, Rafael, E-mail: rjuarez@ind.uned.es [Departamento de Ingeniería Energética, ETSII-UNED, Calle Juan del Rosal 12, Madrid 28040 (Spain); Pampin, Raul [F4E, Torres Diagonal Litoral B3, Josep Pla 2, Barcelona 08019 (Spain); Levesy, Bruno [ITER Organization, 13115 Route de Vinon sur Verdon, St Paul Lez Durance (France); Moro, Fabio [ENEA, Via Enrico Fermi 45, Frascati, Rome (Italy); Suarez, Alejandro [ITER Organization, 13115 Route de Vinon sur Verdon, St Paul Lez Durance (France); Sanz, Javier [Departamento de Ingeniería Energética, ETSII-UNED, Calle Juan del Rosal 12, Madrid 28040 (Spain)

    2015-11-15

    Shutdown dose rates for planned maintenance purposes is an active research field in ITER. In this work the radiation (neutron and gamma) cross-talk between ports in the most conservative case foreseen in ITER is investigated: the presence of a torus cryopump lower port, mostly empty for pumping efficiency reasons. There will be six of those ports: #4, #6, #10, #12, #16 and #18. The equatorial ports placed above them will receive a significant amount of additional radiation affecting the shutdown dose rates during in situ maintenance activities inside the cryostat, and particularly in the port interspace area. In this study a general situation to all the equatorial ports placed above torus cryopump lower ports is considered: a generic diagnostics equatorial port placed above the torus cryopump lower port (LP#4). In terms of shutdown dose rates at equatorial port interspace after 10{sup 6} s of cooling time, 405 μSv/h has been obtained, of which 160 μSv/h (40%) are exclusively due to radiation cross-talk from a torus cryopump lower port. Equatorial port activation due to only “local neutrons” contributes 166 μSv/h at port interspace, showing that radiation cross-talk from such a lower port is a phenomenon comparable in magnitude to the neutron leakage though the equatorial port plug.

  16. Verification of absorbed dose rates in reference beta radiation fields: measurements with an extrapolation chamber and radiochromic film

    International Nuclear Information System (INIS)

    Reynaldo, S. R.; Benavente C, J. A.; Da Silva, T. A.

    2015-10-01

    Beta Secondary Standard 2 (Bss 2) provides beta radiation fields with certified values of absorbed dose to tissue and the derived operational radiation protection quantities. As part of the quality assurance, metrology laboratories are required to verify the reliability of the Bss-2 system by performing additional verification measurements. In the CDTN Calibration Laboratory, the absorbed dose rates and their angular variation in the 90 Sr/ 90 Y and 85 Kr beta radiation fields were studied. Measurements were done with a 23392 model PTW extrapolation chamber and with Gafchromic radiochromic films on a PMMA slab phantom. In comparison to the certificate values provided by the Bss-2, absorbed dose rates measured with the extrapolation chamber differed from -1.4 to 2.9% for the 90 Sr/ 90 Y and -0.3% for the 85 Kr fields; their angular variation showed differences lower than 2% for incidence angles up to 40-degrees and it reached 11% for higher angles, when compared to ISO values. Measurements with the radiochromic film showed an asymmetry of the radiation field that is caused by a misalignment. Differences between the angular variations of absorbed dose rates determined by both dosimetry systems suggested that some correction factors for the extrapolation chamber that were not considered should be determined. (Author)

  17. A case of central type early stage lung cancer receiving 60Co high dose-rate postoperative endobronchial radiation

    International Nuclear Information System (INIS)

    Nakamori, Syouji; Kodama, Ken; Kurokawa, Eiji; Doi, Osamu; Terasawa, Toshio; Chatani, Masashi; Inoue, Toshihiko; Tateishi, Ryuhei

    1985-01-01

    Right middle-lower lobectomy and mediastinal lymph node dissection were performed for a case of central type early stage lung cancer. Tumor extended very closely to the line of incision margin of the resected specimen, appearing as carcinoma in situ. To inprove curativity, postoperative radiation therapy was performed with 60 Co high dose-rate endobronchial radiation by a remote afterloading system. A total dose of 40Gy was administered to the target area without any severe side effects. The patient is healthy and has no evidence of metastasis. This procedure is considered to be an effective treatment for postoperative lung cancer with possible residual malignancy. (author)

  18. Determination of radiation dose rates and urinary activity of patients received Sodium Iodide-131 for treatment of differentiated thyroid carcinoma

    International Nuclear Information System (INIS)

    Beiki, D.; Shahhosseini, S.; Dadashzadeh, S.; Eftekhari, M.; Tayebi, H.; Moosazadeh-Rashti, G.

    2004-01-01

    Sodium Iodide-131 is administrated for treatment of hyperthyroidism and thyroid cancer. Iodine-131 has multiple routs of excretion (urine, saliva, sweat, milk, feces, exhalation) from the body. Patients receiving Sodium Iodide-131 therapy exposes other persons and the environment to unwanted radiation and contamination. The major sources of radiation dose from administration of Iodine-131 is external radiation , also there is a potential for exposure via contamination.Precautions are necessary to limit the radiation dose to family members, nursing staff and members of public and waste treatment workers to less than 1mSv. Patients received Sodium Iodide-131 may come into close contact with other persons. In order to derive appropriate recommendations, dose rates were measured from the anterior mid-trunk of 29 patients in the upright position with 15 minutes post-dose administration at 3 meters and just before they left the nuclear medicine department at 0.5, 1, and 3 meters. We have also measured urinary iodide excretion in 29 patients to estimate Sodium Iodide-131 urinary excretion pattern in iranian patients. Based on results, the maximum cumulative dose to nursing staff was on third day (leaving day) still less than recommended dose bye ICRP. The cumulative dose family members will be more but regarding the time and distance in close contact it will be also less than recommended dose by ICRP.Radiation dose rate was decreased significantly on third day. The urinary excretion patterns in all patients were similar. The urinary excretion rate-time curve in all patients showed multiple peaks due to retention and redistribution of Iodine-131 or enterohepatic cycle of radioiodinated thyroid hormones, which didn't allow calculation of urinary excretion rate constant. The results also showed that 67 hours post administration of Sodium Iodide-131 about 70% of radiopharmaceutical was excreted through urine, 28% physically decayed or eliminated through other biological

  19. ALARA-based strengthening of radiation protection in a high dose rate nuclear power plant: A practical overview

    International Nuclear Information System (INIS)

    Lips, Marcel

    2008-01-01

    In the first years of operation the dose rates at Goesgen nuclear power plant increased more strongly than expected. Co-60 has been the main radiation contributor from the beginning. As an immediate step, investigations were initiated to find and remove unknown cobalt sources. System modifications and optimization in water chemistry were carried out to reduce material and activity transport within the primary system. As a result the dose rates were stabilized after a couple of years -unfortunately on a high level. To reduce the dose rate levels and the occupational radiation exposure, further long term measures were implemented. System decontamination and source replacement were considered as well as the implementation of enhanced shielding procedures and a more source oriented chemistry. As a result the dose rates have reduced significantly and the occupational radiation exposure has been decreased by more than a factor of 2 over the last two decades. The reduction of the mean individual dose turned out even better and was cut by a factor of 5. On terms of plant and personal safety, Goesgen nuclear power plant decided to improve radiation protection using a smooth step by step action plan and has been very successful with it. Currently the technical possibilities have been developed to a high standard. Further improvements will be selective only. In future the focus will be set to personal behavior and human performance, using enhanced target settings, briefings, debriefings, experience feedback and (international) experience exchange. Nevertheless it will be essential to avoid unnecessary administrative and counterproductive short term hurdles. Strengthening of radiation protection is and will be a long term and continuous process. Goesgen nuclear power plant will continue to introduce further actions one by one. (author)

  20. Objective and subjective rating of tonal noise radiated from UK wind farms: Pt. 2

    International Nuclear Information System (INIS)

    1996-01-01

    This final report provides data on the assessment of tonal noise radiation from wind turbines in the United Kingdom. Both objective and subjective assessments of the noise pollution from various wind farms are incorporated in the study. Previous subjective tests are verified here using a larger subject and sample size compared to the initial study. The study also aims to produce an objective automatic tonal assessment procedure which identifies tones and broad band masking noise in wind farm radiated noise spectra. (UK)

  1. Low-dose-rate high-let radiation cytogenetic effects on mice in vivo as model of space radiation action on mammalian

    Science.gov (United States)

    Sorokina, Svetlana; Zaichkina, Svetlana; Rozanova, Olga; Aptikaeva, Gella; Romanchenko, Sergei; Smirnova, Helene; Dyukina, Alsu; Peleshko, Vladimir

    At present time little is known concerning the biological effects of low-dose-rate high-LET radiation exposure in space. The currently available experimental data on the biological effect of low doses of chronic radiation with high-LET values, which occur under the conditions of aircraft and space flights, have been primarily obtained in the examinations of pilots and astronauts after flights. Another way of obtaining this kind of evidence is the simulation of irradiation conditions during aircraft and space flights on high-energy accelerators and the conduction of large-scale experiments on animals under these conditions on Earth. In the present work, we investigated the cytogenetic effects of low-dose-rate high-LET radiation in the dose ranges of 0.2-30 cGy (1 cGy/day) and 0.5-16 cGy (0.43 cGy/day) in the radiation field behind the concrete shield of the Serpukhov accelerator of 70 GeV protons that simulates the spectral and component composition of radiation fields formed in the conditions of high-altitude flights on SHK mice in vivo. The dose dependence, adaptive response (AR) and the growth of solid tumor were examined. For induction of AR, two groups of mice were exposed to adapting doses of 0.2-30 cGy and the doses of 0.5-16 cGy of high-LET radiation. For comparison, third group of mice from unirradiated males was chronically irradiated with X-rays at adapting doses of 10 cGy (1 cGy/day). After a day, the mice of all groups were exposed to a challenging dose of 1.5 Gy of X-rays (1 Gy/min). After 28 h, the animals of all groups were killed by the method of cervical dislocation. Bone marrow specimens for calculating micronuclei (MN) in polychromatic erythrocytes (PCE) were prepared by a conventional method with minor modifications. The influence of adapting dose of 16 cGy on the growth of solid tumor of Ehrlich ascite carcinoma was estimated by measuring the size of the tumor at different times after the inoculation of ascitic cells s.c. into the femur. It was

  2. Chromosome Damage and Cell Proliferation Rates in In Vitro Irradiated Whole Blood as Markers of Late Radiation Toxicity After Radiation Therapy to the Prostate

    Energy Technology Data Exchange (ETDEWEB)

    Beaton, Lindsay A., E-mail: Lindsay.Beaton@hc-sc.gc.ca [Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, ON (Canada); Ferrarotto, Catherine; Marro, Leonora [Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, ON (Canada); Samiee, Sara; Malone, Shawn; Grimes, Scott; Malone, Kyle [The Ottawa Hospital, Ottawa Hospital Research Institute, University of Ottawa, 501 Smyth Rd, Ottawa, ON (Canada); Wilkins, Ruth C. [Environmental and Radiation Health Sciences Directorate, Health Canada, Ottawa, ON (Canada)

    2013-04-01

    Purpose: In vitro irradiated blood samples from prostate cancer patients showing late normal tissue damage were examined for lymphocyte response by measuring chromosomal aberrations and proliferation rate. Methods and Materials: Patients were selected from a randomized trial evaluating the optimal timing of dose-escalated radiation and short-course androgen deprivation therapy. Of 438 patients, 3% experienced grade 3 late radiation proctitis and were considered to be radiosensitive. Blood samples were taken from 10 of these patients along with 20 matched samples from patients with grade 0 proctitis. The samples were irradiated at 6 Gy and, along with control samples, were analyzed for dicentric chromosomes and excess fragments per cell. Cells in first and second metaphase were also enumerated to determine the lymphocyte proliferation rate. Results: At 6 Gy, there were statistically significant differences between the radiosensitive and control cohorts for 3 endpoints: the mean number of dicentric chromosomes per cell (3.26 ± 0.31, 2.91 ± 0.32; P=.0258), the mean number of excess fragments per cell (2.27 ± 0.23, 1.43 ± 0.37; P<.0001), and the proportion of cells in second metaphase (0.27 ± 0.10, 0.46 ± 0.09; P=.0007). Conclusions: These results may be a valuable indicator for identifying radiosensitive patients and for tailoring radiation therapy.

  3. Clinical significance of intraluminal contrast enhancement in patients with spontaneous cervical artery dissection. A black-blood MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Coppenrath, Eva; Lenz, Olga; Sommer, Nora; Treitl, Karla; Reiser, Maximilian [Munich Univ. (Germany). Inst. of Clinical Radiology; Lummel, Nina [Univ. Hospital Klinikum rechts der Isar Munich, Munich (Germany). Inst. of Neuroradiology and Interventional Neuroradiology; Linn, Jennifer [Univ. Hospital Dresden (Germany). Inst. of Neuroradiology; Bamberg, Fabian [Tuebingen Univ. (Germany). Diagnostical and Interventional Radiology; Pfefferkorn, Thomas [Munich Univ. (Germany). Interdisciplinary Stroke Center Munich; Saam, Tobias [Radiology Center Rosenheim (Germany)

    2017-07-15

    Recent studies have suggested that intraluminal thrombi show contrast enhancement on carotid black-blood T1w MRI. The aim of this study was to evaluate the significance of intraluminal contrast enhancement (iCE) regarding symptom status in patients with spontaneous cervical artery dissection (sCAD). 33 consecutive patients (19 men) with sCAD received a brain MRI (DIFF, T2w, T2{sup *}w, FLAIR) and a multi-sequence 3T-MRI with fat-saturated high-resolution black-blood T1w-sequences pre- and post-contrast, contrast-enhanced MR angiography and TOF images of carotid and vertebral arteries. Presence/absence of iCE, vessel occlusion and vessel wall hematoma (hyperintense in T1w pre-contrast) were analysed by two radiologists in consensus decision. 44 of 132 analysed vessels had a vessel wall hematoma, consistent with sCAD. In 17 of 44 dissected vessels an acute ischemic stroke was found. 16 of 17 (94.1 %) vessels ipsilateral to ischemic stroke demonstrated iCE, compared to 9 of 44 (20.4 %) dissected vessels without stroke (P< 0.001). The presence/absence of iCE resulted in a sensitivity, specificity, positive and negative predictive value and accuracy for ischemic stroke of 0.94, 0.67, 0.64, 0.95, and 0.77, respectively, and an odds ratio of 32.0. iCE, which is suggestive of intraluminal thrombus formation, is strongly correlated with ischemic symptoms in patients with sCAD.

  4. Clinical significance of intraluminal contrast enhancement in patients with spontaneous cervical artery dissection. A black-blood MRI study

    International Nuclear Information System (INIS)

    Coppenrath, Eva; Lenz, Olga; Sommer, Nora; Treitl, Karla; Reiser, Maximilian

    2017-01-01

    Recent studies have suggested that intraluminal thrombi show contrast enhancement on carotid black-blood T1w MRI. The aim of this study was to evaluate the significance of intraluminal contrast enhancement (iCE) regarding symptom status in patients with spontaneous cervical artery dissection (sCAD). 33 consecutive patients (19 men) with sCAD received a brain MRI (DIFF, T2w, T2"*w, FLAIR) and a multi-sequence 3T-MRI with fat-saturated high-resolution black-blood T1w-sequences pre- and post-contrast, contrast-enhanced MR angiography and TOF images of carotid and vertebral arteries. Presence/absence of iCE, vessel occlusion and vessel wall hematoma (hyperintense in T1w pre-contrast) were analysed by two radiologists in consensus decision. 44 of 132 analysed vessels had a vessel wall hematoma, consistent with sCAD. In 17 of 44 dissected vessels an acute ischemic stroke was found. 16 of 17 (94.1 %) vessels ipsilateral to ischemic stroke demonstrated iCE, compared to 9 of 44 (20.4 %) dissected vessels without stroke (P< 0.001). The presence/absence of iCE resulted in a sensitivity, specificity, positive and negative predictive value and accuracy for ischemic stroke of 0.94, 0.67, 0.64, 0.95, and 0.77, respectively, and an odds ratio of 32.0. iCE, which is suggestive of intraluminal thrombus formation, is strongly correlated with ischemic symptoms in patients with sCAD.

  5. Genetic Factors Affecting Susceptibility to Low Dose & Low Dose-Rate Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bedford, Joel

    2014-04-18

    Our laboratory has, among other things, developed and used the gamma H2AX focus assay and other chromosomal and cell killing assays to show that differences in this DNA double strand break (dsb) related response can be clearly and distinctly demonstrated for cells which are mildly hyper-radiosensitive such as those associated with A-T heterozygosity. We have found this level of mild hypersensitivity for cells from some 20 to 30 % of apparently normal individuals and from apparently normal parents of Retinoblastoma patients. We found significant differences in gene expression in somatic cells from unaffected parents of Rb patients as compared with normal controls, suggesting that these parents may harbor some as yet unidentified genetic abnormality. In other experiments we sought to determine the extent of differences in normal human cellular reaponses to radiation depending on their irradiation in 2D monolayer vs 3D organized acinar growth conditions. We exmined cell reproductive death, chromosomal aberration induction, and the levels of γ-H2AX foci in cells after single acute gamma-ray doses and immediately after 20 hours of irradiation at a dose rate of 0.0017 Gy/min. We found no significant differences in the dose-responses of these cells under the 2D or 3D growth conditions. While this does not mean such differences cannot occur in other situations, it does mean that they do not generally or necessarily occur. In another series of studies in collaboration with Dr Chuan Li, with supprt from this current grant. We reported a role for apoptotic cell death in promoting wound healing and tissue regeneration in mice. Apoptotic cells released growth signals that stimulated the proliferation of progenitor or stem cells. In yet another collaboration with Dr, B. Chen with funds from this grant, the relative radiosensitivity to cell killing as well as chromosomal instability of 13 DNA-PKcs site-directed mutant cell lines (defective at phosphorylation sites or kinase

  6. Predictive analysis of the radiation exposure for the primary cooling system of the rated power operation of MONJU

    International Nuclear Information System (INIS)

    Matuo, Youichirou; Miyahara, Shinya; Hasegawa, Masanori; Maegawa, Yoshiharu

    2011-01-01

    Radioactive corrosion products (CP) are main source of personal radiation exposure during maintenance without fuel-failure accident in the Liquid-Metal Fast Breeder Reactor (LMFBR) plants. In order to establish the techniques of radiation dose estimation for personnel, program system 'DORE' has been developed. The DORE system is constructed by PSYCHE code and QAD code system. The density of each deposited CP of primary coolant system in MONJU was estimated by using the PSYCHE. Moreover, the QAD-CGGP2R code is applied to dose rate calculations for the primary coolant system in MONJU. The dose rate around primary piping system was visualized using AVS software. The predicted values were estimated to be saturated at 2-3 mSv/h in twenty years after the start of operation, and the dose rate reaches 4 mSv/h in domains near the IHX and the cold-leg piping. It has been assumed that the main radiation source is 54 Mn in the IHX, primary pump and cold-leg piping region. On the other hand, it was indicated that the contribution to dose rate of the 60 Co accounted for approximately 23% in the hot-leg piping region. (author)

  7. Effects of low power microwave radiation on biological activity of Collagenase enzyme and growth rate of S. Cerevisiae yeast

    Science.gov (United States)

    Alsuhaim, Hamad S.; Vojisavljevic, Vuk; Pirogova, E.

    2013-12-01

    Recently, microwave radiation, a type/subset of non-ionizing electromagnetic radiation (EMR) has been widely used in industry, medicine, as well as food technology and mobile communication. Use of mobile phones is rapidly growing. Four years from now, 5.1 billion people will be mobile phone users around the globe - almost 1 billion more mobile users than the 4.3 billion people worldwide using them now. Consequently, exposure to weak radiofrequency/microwave radiation generated by these devices is markedly increasing. Accordingly, public concern about potential hazards on human health is mounting [1]. Thermal effects of radiofrequency/microwave radiation are very well-known and extensively studied. Of particular interest are non-thermal effects of microwave exposures on biological systems. Nonthermal effects are described as changes in cellular metabolism caused by both resonance absorption and induced EMR and are often accompanied by a specific biological response. Non-thermal biological effects are measurable changes in biological systems that may or may not be associated with adverse health effects. In this study we studied non-thermal effects of low power microwave exposures on kinetics of L-lactate dehydrogenase enzyme and growth rate of yeast Saccharomyces Cerevisiae strains type II. The selected model systems were continuously exposed to microwave radiation at the frequency of 968MHz and power of 10dBm using the designed and constructed (custom made) Transverse Electro-Magnetic (TEM) cell [2]. The findings reveal that microwave radiation at 968MHz and power of 10dBm inhibits L-lactate dehydrogenase enzyme activity by 26% and increases significantly (15%) the proliferation rate of yeast cells.

  8. Diversification rates indicate an early role of adaptive radiations at the origin of modern echinoid fauna.

    Directory of Open Access Journals (Sweden)

    Simon Boivin

    Full Text Available Evolutionary radiations are fascinating phenomena corresponding to a dramatic diversification of taxa and a burst of cladogenesis over short periods of time. Most evolutionary radiations have long been regarded as adaptive but this has seldom been demonstrated with large-scale comparative datasets including fossil data. Originating in the Early Jurassic, irregular echinoids are emblematic of the spectacular diversification of mobile marine faunas during the Mesozoic Marine Revolution. They diversified as they colonized various habitats, and now constitute the main component of echinoid fauna in modern seas. The evolutionary radiation of irregular echinoids has long been considered as adaptive but this hypothesis has never been tested. In the present work we analyze the evolution of echinoid species richness and morphological disparity over 37 million years based on an extensive fossil dataset. Our results demonstrate that morphological and functional diversifications in certain clades of irregular echinoids were exceptionally high compared to other clades and that they were associated with the evolution of new modes of life and so can be defined as adaptive radiations. The role played by ecological opportunities in the diversification of these clades was critical, with the evolution of the infaunal mode of life promoting the adaptive radiation of irregular echinoids.

  9. A Generalized Approach to Model the Spectra and Radiation Dose Rate of Solar Particle Events on the Surface of Mars

    Science.gov (United States)

    Guo, Jingnan; Zeitlin, Cary; Wimmer-Schweingruber, Robert F.; McDole, Thoren; Kühl, Patrick; Appel, Jan C.; Matthiä, Daniel; Krauss, Johannes; Köhler, Jan

    2018-01-01

    For future human missions to Mars, it is important to study the surface radiation environment during extreme and elevated conditions. In the long term, it is mainly galactic cosmic rays (GCRs) modulated by solar activity that contribute to the radiation on the surface of Mars, but intense solar energetic particle (SEP) events may induce acute health effects. Such events may enhance the radiation level significantly and should be detected as immediately as possible to prevent severe damage to humans and equipment. However, the energetic particle environment on the Martian surface is significantly different from that in deep space due to the influence of the Martian atmosphere. Depending on the intensity and shape of the original solar particle spectra, as well as particle types, the surface spectra may induce entirely different radiation effects. In order to give immediate and accurate alerts while avoiding unnecessary ones, it is important to model and well understand the atmospheric effect on the incoming SEPs, including both protons and helium ions. In this paper, we have developed a generalized approach to quickly model the surface response of any given incoming proton/helium ion spectra and have applied it to a set of historical large solar events, thus providing insights into the possible variety of surface radiation environments that may be induced during SEP events. Based on the statistical study of more than 30 significant solar events, we have obtained an empirical model for estimating the surface dose rate directly from the intensities of a power-law SEP spectra.

  10. Effects of radiation transport on mass ablation rate and conversion efficiency in numerical simulations of inertial confinement fusion

    International Nuclear Information System (INIS)

    Gupta, N.K.

    2002-01-01

    The effects of radiation transport on hydrodynamic parameters of laser produced plasmas are studied. LTE and non-LTE atomic models are used to calculate multi group opacities and emissivities. Screened hydrogenic atom model is used to calculate the energy levels. The population densities of neutral to fully ionized ions are obtained by solving the steady state rate equations. Radiation transport is treated in multi-group diffusion or Sn method. A comparison is made between 1 and 100 group radiation transport and LTE and non-LTE models. For aluminium, multi group radiation transport leads to much higher mass ablation as compared to the 1 group and no radiation transport cases. This in turn leads to higher ablation pressures. However, for gold gray approximation gives higher mass ablation as compared to multi group simulations. LTE conversion efficiency of laser light into x-rays is more than the non-LTE estimates. For LTE as well as non-LTE cases, the one group approximation over-predicts the conversion efficiency Multi group non-LTE simulations predict that the conversion efficiency increases with laser intensity up to a maximum and then it decreases. (author)

  11. Dichromatic and monochromatic laser radiation effects on antibiotic resistance, biofilm formation, and division rate of Pantoea agglomerans

    Science.gov (United States)

    Thomé, A. M. C.; Souza, B. P.; Mendes, J. P. M.; Cardoso, A. F. R.; Soares, L. C.; Trajano, E. T. L.; Fonseca, A. S.

    2018-06-01

    Since infection is a common cause of delayed wound healing, it is important to understand the effect of low-level laser therapy (LLLT) in bacterial mechanisms. In this study we evaluated the effects of LLLT on antibiotic resistance, division rate, and biofilm formation of Pantoea agglomerans. P. agglomerans samples were isolated from human pressure injuries in humans and cultures were exposed to low-level monochromatic and simultaneous dichromatic laser radiation to study the susceptibility of an antimicrobial to ampicillin and piperacillin  +  tazobactam, quantification of areas of bacterial colonies, and biofilm formation of bacterial cells. Fluence, wavelength, and emission mode were used in the therapeutic protocols for wound healing. The data showed no changes in the areas of the colonies, but dichromatic laser radiation decreased biofilm formation, while a monochromatic red laser at low dose increased biofilm formation and infrared at high dose decreased antibiotic resistance to ampicillin. LLLT modulates antibiotic resistance and biofilm formation of P. agglomerans, but these depend on the laser irradiation parameters, since dichromatic laser radiation induces biological effects that differ from those induced by monochromatic laser radiation. Thus, simultaneous dichromatic low-level red and infrared lasers could be a new option for the treatment of infected wounds, reducing biofilm formation, without altering antibiotic resistance and the division rate of P. agglomerans cultures.

  12. Radiation dose rates from commercial PWR and BWR spent fuel elements

    International Nuclear Information System (INIS)

    Willingham, C.E.

    1981-10-01

    Data on measurements of gamma dose rates from commercial reactor spent fuel were collected, and documented calculated gamma dose rates were reviewed. As part of this study, the gamma dose rate from spent fuel was estimated, using computational techniques similar to previous investigations into this problem. Comparison of the measured and calculated dose rates provided a recommended dose rate in air versus distance curve for PWR spent fuel

  13. Sweat Rate Prediction Equations for Outdoor Exercise with Transient Solar Radiation

    Science.gov (United States)

    2012-01-01

    AD] 15 Interchangeable variables gSL W/m2 Global solar load Direct weather station data; pyranometer values 25 Direct measurement from weather station... pyranometer (to measure short-wave radiation fluxes) and pyrgeometer (to measure long-wave radiation fluxes). Normally, the value of the solar load...as described below. During field operations, Rsol (W/m2) can be calculated from 0.835 ·ERF. If Rsol (in W/m2) is known by direct pyranometer mea

  14. Specific-locus mutation frequencies in mouse stem-cell spermatogonia at very low radiation dose rates, and their use in the estimation of genetic hazards of radiation in man

    International Nuclear Information System (INIS)

    Russell, W.L.; Kelly, E.M.

    1982-01-01

    Experiments were undertaken to augment the information on the lowest radiation dose rates feasible for scoring transmitted induced mutations detected by the specific-locus method in the mouse. This is the type of information most suitable for estimating genetic hazards of radiation in man. The results also aid in resolving conflicting possibilities about the relationship between mutation frequency and radiation dose at low dose rates

  15. Epidemiological studies on disturbances of human fetal development in areas with various doses of natural background radiation. I. Relationship between incidences of Down's syndrome or visible malformation and gonad dose equivalent rate of natural background radiation

    International Nuclear Information System (INIS)

    Ujeno, Y.

    1985-01-01

    The relationship between environmental radiation to the gonads and incidences of Down's syndrome and visible malformation was analyzed using Kendall's rank correlation method. The subjects, studied during a 3-yr period (1979-1981), were inhabitants of 46 prefectures in Japan that had various dose rates of natural background ionizing radiation. Results showed that the natural background very low-dose radiation rate was not a predominant factor responsible for inducing Down's syndrome or other visible malformations

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  17. Radiation utilization efficiency, nitrogen uptake and modeling crop growth and yield of rainfed rice under different nitrogen rates

    International Nuclear Information System (INIS)

    Gouranga, Kar; Ashwani Kumar; Mohapatra, Sucharita

    2014-01-01

    Optimum utilization of photosynthetically active radiation (PAR) along with proper nitrogen (N) management for sustainable rice production is still a promising management recommendation for sustainable rainfed rice cultivation in eastern India. The objective of this investigation was to study radiation utilization efficiency (RUE), N uptake and modeling growth and productivity of wet/rainy season rice (cv. Lalat and Gayatri) under 0, 50, 90, 120 and 150 kg ha -1 N application. Results showed that N rates significantly affected plant biomass, leaf area index (LAI), biological yield (straw and grain yield) and N uptake for both the varieties. The intercepted photosynthetically active radiation (IPAR) and spectral reflectance based vegetation indices (IR/R, NDVI) were also different between two varieties and among N rates. Higher rate of N increased the RUE significantly; averaged over years and varieties, mean values of RUE were 1.35, 1.70, 2.01, 2.15 and 2.17 g MJ -1 under 0, 50, 90, 120 and 150 kg N ha -1 , respectively. Though crop growth, yield, N uptake and RUE were higher at 150 kg N ha -1 but the results were at par with 120 kg N ha -1 . Agronomic N use efficiency (ANUE) was also low at 150 kg N ha -1 . The DSSAT v 4.5 model was applied to simulate crop growth, yield and phenology of the crop under different N rates. Model performance was found to be poor at low N rates (0, 50 kg N ha -1 ), but the model performed fairly well at higher N rates (90 kg ha -1 and above). (author)

  18. Solar Radiation Disinfection of Drinking Water at Temperate Latitudes: Inactivation rates for an optimized reactor configuration

    Science.gov (United States)

    Solar radiation-driven inactivation of bacteria, virus and protozoan pathogen models was quantified in simulated drinking water at a temperate latitude (34°S). The water was seeded with Enterococcus faecalis, Clostridium sporogenes spores, and P22 bacteriophage, each at ca 1 x 10...

  19. Objective and subjective rating of tonal noise radiated from UK wind farms

    International Nuclear Information System (INIS)

    1996-01-01

    The radiation of noise to the environment is currently a major issue with regard to U.K. wind farm developments. The reason for this concern is not that wind turbines are unduly noisy, but rather because wind farms are often located in rural areas where background noise levels can fall very low. The fact that background noise levels fall so low in these areas means that the permissible noise radiation from wind farms must also be kept similarly low if nuisance to local residents is to be avoided. However, ensuring that the overall noise level of the wind farm does not exceed the pre-existing background noise level by more than a set amount is not the whole story. Noise radiated from wind turbines can exhibit characteristics that set it apart from the natural background noises typically found in quiet rural areas, where ''natural'' background noises might include the sound of the wind blowing through trees, or the sound of running water. One of the acoustic characteristics that can be attributed to some wind turbines is the radiation of tonal noise from mechanical plant located in the nacelles. It is well accepted that tonal components in otherwise broad band, or ''characterless'', noise, can increase the subjective perception of that noise. Account for increased annoyance due to tones is found in both of the British Standards which relate to environmental noise; BS4142 and BS7445. (UK)

  20. Responses of rat R-1 cells to low dose rate gamma radiation and multiple daily dose fractions

    International Nuclear Information System (INIS)

    Kal, H.B.; Bijman, J.Th.

    1981-01-01

    Multifraction irradiation may offer the same therapeutic gain as continuous irradiation. Therefore, a comparison of the efficacy of low dose rate irradiation and multifraction irradiation was the main objective of the experiments to be described. Both regimens were tested on rat rhabdomyosarcoma (R-1) cells in vitro and in vivo. Exponentially growing R-1 cells were treated in vitro by a multifraction irradiation procedure with dose fractions of 2 Gy gamma radiation and time intervals of 1 to 3 h. The dose rate was 1.3 Gy.min -1 . The results indicate that multifractionation of the total dose is more effective with respect to cell inactivation than continuous irradiation. (Auth.)

  1. Activation of the JET vacuum vessel: a comparison of calculated with measured gamma-radiation fluxes and dose rates

    International Nuclear Information System (INIS)

    Jarvis, O.N.; Sadler, G.; Avery, A.; Verschuur, K.A.

    1988-01-01

    The gamma-radiation dose-rates inside the JET vacuum vessel due to induced radioactivity were measured at intervals throughout the 1986 period of operation, and the decay gamma energy spectrum was measured during the subsequent lengthy shutdown. The dose-rates were found to be in good agreement with values calculated using the neutron yield records compiled from the time-resolved neutron yield monitor responses for individual discharges. This result provides strong support for the reliability of the neutron yield monitor calibration. (author)

  2. Dose-rate and humidity effects upon the gamma-radiation response of nylon-based radiachromic film dosimeters

    International Nuclear Information System (INIS)

    Gehringer, P.; Eschweiler, H.; Proksch, E.

    1979-10-01

    At dose-rates typical for 60 Co gamma irradiation sources, the radiation response of hexahydroxyethyl pararosaniline cyanide/ 50μm nylon radiachromic films is dependent upon dose-rate as well as upon the moisture content of the films, or the relative humidity of the surrounding atmosphere, respectively. Under equilibrium moisture conditions, the response measured at 606 nm 24 hours after end of irradiation shows its highest dose-rate dependence at about 32 % r.h. A decrease in dose-rate from 2.8 to 0.039 Gy.s -1 results in a decrease in response by 17%. At higher humidities, the sensitivity of the film as well as the rate dependence decreases and at 86% r.h. no discernible dose-rate effect could be found. At lower humidities than 32% a flat maximum in response follows. At nominal 0% r.h. a second absorption band at 412 nm appears which is converted completely to an additional 606 nm absorption by exposure to a humid atmosphere. After that procedure the resultant response is somewhat lower than but shows almost the same dose-rate dependence as at 32% r.h. or else to eliminate the dose-rate effect by an extrapolation procedure based on the fact that the rate dependence vanishes at zero dose. (author)

  3. Environmental radiation monitoring: mobile gamma dose rate measurements along Mumbai-Hyderabad rail route and Hyderabad city roads

    International Nuclear Information System (INIS)

    Divkar, J.K.; Padmanabhan, N.; Chaudhury, Probal; Pradeepkumar, K.S.; Pujari, R.N.; Dogra, Santosh; Sharma, D.N.; Rajagopalan, S.; Srivastava, G.K.

    2005-01-01

    Environmental Radiation monitoring based on gamma dose rate logging on a mobile platform integrated with real time position from a Global Positioning System is an effective tool to acquire dose rate profile and generate radiological map of any geographical region. The microcontroller based dose rate data acquisition system capable of storing the acquired data and transferring to an attached laptop/PC and providing a graphical illustration of relative variations in gamma background can also be used for quick assessment of environmental radiological impact assessment. This paper describes the methodology and results of the environmental gamma dose rate monitoring surveys carried out: (i) on Mumbai-Hyderabad rail route with the systems installed in the trains guard's room and (ii) Hyderabad city roads with systems installed in a monitoring van. The results indicate significant difference in the gamma background measured along the rail route between Mumbai-Hyderabad and in the radiological map generated after the Hyderabad city survey. (author)

  4. Assessing the effusion rate of lava flows from their thermal radiated energy: theoretical study and lab-scale experiments

    Science.gov (United States)

    Garel, F.; Kaminski, E.; Tait, S.; Limare, A.

    2010-12-01

    A quantitative monitoring of lava flow is required to manage a volcanic crisis, in order to assess where the flow will go, and when will it stop. As the spreading of lava flows is mainly controlled by its rheology and the eruptive mass flux, the key question is how to evaluate them during the eruption (rather than afterwards.) A relationship between the lava flow temperature and the eruption rate is likely to exist, based on the first-order argument that higher eruption rates should correspond to larger energy radiated by a lava flow. The semi-empirical formula developed by Harris and co-workers (e.g. Harris et al., 2007) is used to estimate lava flow rate from satellite observations. However, the complete theoretical bases of this technique, especially its domain of validity, remain to be firmly established. Here we propose a theoretical study of the cooling of a viscous axisymmetric gravity current fed at constant flux rate to investigate whether or not this approach can and/or should be refined and/or modify to better assess flow rates. Our study focuses on the influence of boundary conditions at the surface of the flow, where cooling can occur both by radiation and convection, and at the base of the flow. Dimensionless numbers are introduced to quantify the relative interplay between the model parameters, such as the lava flow rate and the efficiency of the various cooling processes (conduction, convection, radiation.) We obtain that the thermal evolution of the flow can be described as a two-stage evolution. After a transient phase of dynamic cooling, the flow reaches a steady state, characterized by a balance between surface and base cooling and heat advection in the flow, in which the surface temperature structure is constant. The duration of the transient phase and the radiated energy in the steady regime are shown to be a function of the dimensionless numbers. In the case of lava flows, we obtain that the steady state regime is reached after a few days. In

  5. Radiation Dose-Rate Extraction from the Camera Image of Quince 2 Robot System using Optical Character Recognition

    International Nuclear Information System (INIS)

    Cho, Jai Wan; Jeong, Kyung Min

    2012-01-01

    In the case of the Japanese Quince 2 robot system, 7 CCD/CMOS cameras were used. 2 CCD cameras of Quince robot are used for the forward and backward monitoring of the surroundings during navigation. And 2 CCD (or CMOS) cameras are used for monitoring the status of front-end and back-end motion mechanics such as flippers and crawlers. A CCD camera with wide field of view optics is used for monitoring the status of the communication (VDSL) cable reel. And another 2 CCD cameras are assigned for reading the indication value of the radiation dosimeter and the instrument. The Quince 2 robot measured radiation in the unit 2 reactor building refueling floor of the Fukushima nuclear power plant. The CCD camera with wide field-of-view (fisheye) lens reads indicator of the dosimeter loaded on the Quince 2 robot, which was sent to carry out investigating the unit 2 reactor building refueling floor situation. The camera image with gamma ray dose-rate information is transmitted to the remote control site via VDSL communication line. At the remote control site, the radiation information in the unit 2 reactor building refueling floor can be perceived by monitoring the camera image. To make up the radiation profile in the surveyed refueling floor, the gamma ray dose-rate information in the image should be converted to numerical value. In this paper, we extract the gamma ray dose-rate value in the unit 2 reactor building refueling floor using optical character recognition method

  6. Radiation Dose-Rate Extraction from the Camera Image of Quince 2 Robot System using Optical Character Recognition

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Jeong, Kyung Min [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    In the case of the Japanese Quince 2 robot system, 7 CCD/CMOS cameras were used. 2 CCD cameras of Quince robot are used for the forward and backward monitoring of the surroundings during navigation. And 2 CCD (or CMOS) cameras are used for monitoring the status of front-end and back-end motion mechanics such as flippers and crawlers. A CCD camera with wide field of view optics is used for monitoring the status of the communication (VDSL) cable reel. And another 2 CCD cameras are assigned for reading the indication value of the radiation dosimeter and the instrument. The Quince 2 robot measured radiation in the unit 2 reactor building refueling floor of the Fukushima nuclear power plant. The CCD camera with wide field-of-view (fisheye) lens reads indicator of the dosimeter loaded on the Quince 2 robot, which was sent to carry out investigating the unit 2 reactor building refueling floor situation. The camera image with gamma ray dose-rate information is transmitted to the remote control site via VDSL communication line. At the remote control site, the radiation information in the unit 2 reactor building refueling floor can be perceived by monitoring the camera image. To make up the radiation profile in the surveyed refueling floor, the gamma ray dose-rate information in the image should be converted to numerical value. In this paper, we extract the gamma ray dose-rate value in the unit 2 reactor building refueling floor using optical character recognition method

  7. Knowledge on radiation dose-rate for risk communication on nuclear power plants

    International Nuclear Information System (INIS)

    Sugiyama, Ken-ichiro

    2013-01-01

    The sense of anxiety on radiation after Fukushima Dai-ichi accident has not disappeared because of the nightmare scenario on radiation cultivated through the Cold War era starting at the atomic bomb dropping at Hiroshima and Nagasaki. In the present paper, from the viewpoint of establishing the social acceptance of nuclear power plants as well as new reasonable regulation, biological defense in depth (production of anti-oxidants, DNA repair, cell death/apoptosis, and immune defense mechanisms) found in a few decades are presented in comparison with the linear no-threshold (LNT) model for the induction of cancer in the range up to 100 mSv (as single or annual doses) applied for the present regulation. (author)

  8. Early growth rates and their relationships to mortalities of five breeds of chickens following exposure to acute gamma radiation stress

    International Nuclear Information System (INIS)

    Latimer, B.E.; Brisbin, I.L. Jr.

    1987-01-01

    Growth and mortality responses were recorded for 541 chicks, representing five different breeds of chickens, following acute exposures to gamma radiation stress at two days of age. Although there were no statistically significant differences in the LD50/30 of the five breeds studied, Cobb broilers showed the highest (1580R) and White Leghorn bantams the lowest (980R) levels, respectively. Other breeds studied included the standard White Leghorn, Athens Randombreds and a strain of feral bantam. Growth rates of body weights were proportionately more depressed by radiation stress than were body sizes, as measured by the lengths of the culmen, tarsus, middle toe and longest primary wing feather of all 32 day-old survivors. Among these structures, the length of the culmen seemed to be the least affected by radiation stress in all of the breeds studied. Feral bantams were able to tolerate the greatest depression in weight gain before exhibiting mortality at exposures below their LD50/30' while Cobb broilers tolerated the greatest depression of weight gain at higher exposure levels. There was a suggestion that those characteristics which were strongly selected for in the course of a particular breed's development were those which experienced the greatest proportional depressions following exposure to gamma radiation stress

  9. A Nonequilibrium Finite-Rate Carbon Ablation Model for Radiating Earth Re-entry Flows

    Science.gov (United States)

    2015-09-17

    debted to Steven Lewis, Guerric De Crombrugghe de Looringhe, Dr. Troy Eichmann , Dr. Timothy McIntyre, and Dr. Richard Morgan for their assistance in... Eichmann [29]). 20 Figure 8. Side view of UV spectrometer capture area on the model (slit height not to scale, adapted from Zander et al. [133...2011. 29. Eichmann , T. N. Radiation Measurements in a Simulated Mars Atmosphere. Ph.D. thesis, The University of Queensland, 2012. 30. Glass, D. E., R

  10. Relative radiative decay rates of vacancies in L-subshells of heavy elements

    International Nuclear Information System (INIS)

    Barros Leite, C.V. de; Pinho, A.G. de; Castro Faria, N.V. de.

    1977-01-01

    Relative radiative decay of vacancies in L-subshells were measured for a large number of heavy elements with a Si(Li) detection system. A graphical method was employed to analyze the x-ray spectra so obtained. Systematic results are presented together with other already published results obtained in our laboratories in recent years. This covers the interval 74<=Z<=93. Results are compared with theoretical predictions and experimental data from other authors and some general features are noted

  11. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    International Nuclear Information System (INIS)

    Levy, R.P.

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute γ-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain

  12. Survival of tumor bearing mice by sequencing of low dose rate (LDR) neutron and photon radiation

    International Nuclear Information System (INIS)

    Onomura, C.I.; Feola, J.M.; Maruyama, Y.

    1984-01-01

    Cf-252 neutron radiation (NT) has been shown to be effective therapy for bulky, hypoxic human tumor and to produce consistent rapid clearance and 5 year cures. NT has been found to be more or less effective depending upon the schedule in which it is used and upon mixing with photon radiation. In an effort to study this scheduling and photon effect, LSA tumor was irradiated in vivo in a hypoxic, advanced state, in different schedules in combination of NT with Co-60 photons. The LSA lymphoma of C57BL/ym mice represents an accurate system to assess dose-response of tumor cells in vivo. Mean survival time was used as endpoint. A high RBE for LDR Cf-252 NT was observed with a RBE(n) of -- 5.0. The effect was not greatly sensitive to sequence in which photons were used. Comparison studies were also tested relative to LDR Cs-137 photon radiation. The results support the high efficacy of LDR NT for destruction of hypoxic tumor in vivo

  13. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Richard P. [Univ. of California, Berkeley, CA (United States)

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute γ-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain.

  14. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, R.P.

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute {gamma}-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain.

  15. The influence of gamma radiation rate over the radiosensitivity of five class of insects

    International Nuclear Information System (INIS)

    Domarco, R.E.

    1977-01-01

    This paper was aimed at studying the influence of gamma rays dose rate over the radiosensitivity of Sitophilus oryzae (L.), S. zeamais Mots., Rhyzopertha dominica (F.), Zabrotes subfasciatus (Boh.) and Ceratitis capitata Wied. From the results obtained it can be observed that: a) When adults of S. oryzae and S. zeamais were irradiated with either very low dose rates (35, 63, 154 and 632 rad/hour) or very high dose rates (59,580 rad/hour) they showed an increase in their life expectancies, which decreased under intermediate dose rates (2,750 and 15,750 rad/hour). With R. dominica, however, there was continued decrease in life expectancy as the dose rate increased. b) There was a higher emergence of larvae of C. capitata when the eggs were irradiated with low dose rates (1.7, 6.8, 10.9 and 43.9 krad/hour) and with high dose rates (1,577 and 3,759 krad/hour), while the intermediate dose rates (131,330 and 654 krad/hour) were more effective towards causing egg mortality. c) When adults of Z. subfasciatus were irradiated with low dose rates (1.6, 6.7 and 10.8 krad/hour) they underwent a small alteration in life expectancy, mainly for the male insects, while higher dose rates (43.3 krad/hour or more) did not have any influence. (author)

  16. Predicting radiation effects on the development of leukemic stem cells based on studies of leukemias induced by high- and low-dose-rate radiation

    International Nuclear Information System (INIS)

    Hirouchi, Tokuhisa

    2012-01-01

    One of the most important causes of radiation-induced cancers, particularly leukemia, is gene mutations resulting from single and double strand breaks in the DNA. Tanaka et al. (2003) reported life shortening in specific pathogen free male and female B6C3F1 mice continuously exposed to γ rays at a low dose rate of 20 mGy/22 h/d for 400 days from 8 weeks of age. Early death due to cancer, mostly malignant lymphomas, was observed in both sexes. A significant increase in the incidence of myeloid leukemia, resulting in early death, was also reported in males. It is expected however, that at 20 mGy/22 h/d, which is equivalent to a dose of 15 μGy/min, DNA strand breaks induced in these cells are repaired soon after they occur. Murine leukemias induced by high-dose-rate radiation were also found in males, and 80% of the mice with leukemia had hemizygous deletions in chromosome 2 around the PU.1 gene and they appeared to be derived from DNA strand breaks. Majority of these leukemia showing hemizygous deletions in chromosome 2 revealed point mutations in the remaining alleles resulting in PU.1 inactivation, which was reported to be related to leukemogenesis. These point mutations are assumed to be independent of DNA strand breaks that occur immediately after irradiation, as they appear at later time after irradiation. This review discusses the effect of radiation-induced DNA strand breaks and also mutagenesis induced independently of DNA strand breaks in hematopoietic cells contributing to the development of the first leukemic stem cell. (author)

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

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  18. Comparison of Radiation Dose Rates with the Flux to Dose Conversion Factors Recommended in ICRP-74 and ICRP-116

    International Nuclear Information System (INIS)

    Jeong, Hae Sun; Kil, A Reum; Lee, Jo Eun; Jeong, Hyo Joon; Kim, Eun Han; Han, Moon Hee; Hwang, Won Tae

    2016-01-01

    The evaluation of radiation shielding has been performed for the design and maintenance of various facilities using radioactive sources such as nuclear fuel, accelerator, and radionuclide. The conversion of flux to dose mainly used in nuclear and radiation fields has been generally made with the dose coefficients presented in ICRP Publication 74 (ICRP- 74), which are produced based on ICRP Publication 60. On the other hand, ICRP Publication 116 (ICRP-116), which adopts the protection system of ICRP Publication 103, has recently been published and provides the dose conversion coefficients calculated with a variety of Monte Carlo codes. The coefficients have more than an update of those in ICRP-74, including new particle types and a greatly expanded energy range. In this study, a shielding evaluation of a specific container for neutron and gamma sources was performed with the MCNP6 code. The dose rates from neutron and gamma-ray sources were calculated using the MCNP6 codes, and these results were based on the flux to dose conversion factors recommended in ICRP-74 and ICRP-116. As a result, the dose rates evaluated with ICRP-74 were generally shown higher than those with ICRP-116. For neutrons, the difference is mainly occurred by the decrease of radiation weighting factors in a part of energy ranges in the ICRP-116 recommendations. For gamma-rays, the ICRP-74 recommendation applied with the kerma approximation leads to overestimated results than the other assessment

  19. Influence of Parotid from Various Dose Rate in Intensity Modulated Radiation Therapy Planning for Head and Neck Cancer

    International Nuclear Information System (INIS)

    Hong, Joo Wan; Jeong, Yun Ju; Won, Hui Su; Chang, Nam Jun; Choi, Ji Hun; Seok, Jin Yong

    2010-01-01

    There are various beam parameter in intensity modulated radiation therapy (IMRT). The aim of this study is to investigate how various dose rate affect the parotid in treatment plan of IMRT. Materials and Methods: The study was performed on 10 nasopharyngeal carcinoma patients who have undergone IMRT. CT images were scanned 3 mm of thickness in the same condition and the treatment plan was performed by Eclipse (Ver.7.1, Varian, Palo Alto, USA). The parameters for planning used 6 MV energy and 8 beams under the same dose volume constraint. The variation of dose rates were used 300, 400, 500 MU/min. The mean dose of both parotid was accessed from the calculated planning among the 10 patients. The mean dose of parotid was verificated by 2D diode array (Mapcheck from Sun Nuclear Corporation, Melbourne, Florida). Also, Total monitor unit (MU) and beam-on time was analysed. Results: According to the dose rate, the mean dose of parotid was increased by 0.8%, 2.0% each, when dose rate was changed from 300 MU/min to 400, 500 MU/min, moreover Total MU was increased by 5.4% and 10.6% each. There was also a dose upward trend in the dose measurement of parotid by 2D diode array. However, beam - on time difference of 1-2 minutes was no significant in the dose rate increases. From this study, when the dose rates increase, there was a significant increase of Total MU and the parotid dose accordingly, however the shortened treatment time was not significant. Hence, it is considered that there is a significant decrease of late side effect in parotid radiation therapy, if the precise dose rate in IMRT is used.

  20. The effect of composition of mixture on rate of radiation initiation of chain reactions

    International Nuclear Information System (INIS)

    Poluehktov, V.A.; Begishev, I.R.; Podkhalyuzin, A.T.; Babkina, Eh.I.; Morozov, V.A.; Shapovalov, V.V.

    1977-01-01

    The effect of the composition of starting components on the rate of a number of chain liquid-phase reactions initiated by γ-quanta of Co 60 has been investigated at constant temperature and dosage rate. In regard to 1,1-difluoroethane chlorination, cyclohexene phosphorylation and adamantane alkylation with hexafluoropropylene reactions, abnormal effect of the reagent compositions on reaction rates has been discovered. The possible radical - starting molecule complexing reaction and molecular complexing from the starting components have been considered

  1. Mathematical modelling of the death rate dynamics in mammals with intestinal form of radiation sicleness

    International Nuclear Information System (INIS)

    Smirnova, O.A.

    1990-01-01

    A mathematical models has been developed to describe the death rate dynamics in irradiated mammals. The model links statistical biometric functions with statistical and dynamic characteristics of the organism's 'critical' system. There is an agreement between the results of modelling and experiments with respect to death rate dynamics of small laboratory animals subjected to acute and chronic irradiation with doses and dose-rates at which small intestine epithelium is 'ctitical'

  2. Conventional external beam radiation therapy and high dose rate afterloading brachytherapy as a boost for patients older than 70 years

    International Nuclear Information System (INIS)

    Pellizzon, Antonio Cassio Assis; Salvajoli, Joao Vitor; Fogaroli, Ricardo Cesar; Novaes, Paulo Eduardo R.S.; Maia, Maria Aparecida Conte; Ferrigno, Robson

    2005-01-01

    The treatment options for patients with non metastatic prostate cancer range from observation, radical prostatectomy, radiation therapy, hormonal therapy to various combination of some to all of them. Objective: we evaluated the impact on biochemical control of disease (bNED), acute and late intestinal (GI) and urological (GU) morbidity for a group of patients older than 70 years presenting initial or locally advanced prostate cancer treated with fractionated high dose rate brachytherapy (HDRB) as a boost to conventional external beam radiation therapy (RT) at the Department of Radiation Oncology from Hospital do Cancer A. C. Camargo, Sao Paulo, Brazil. Methods: a total of 56 patients older than 70 were treated from March, 1997 to June, 2002. All patients had prior to HDRB a course of RT to a median dose of 45 Gy. HDRB doses ranged from 16 Gy to 20 Gy, given in 4 fractions. Results: the median age of the patients was 74.4 years (range 70-83) and the median follow-up 33 months (range 24 to 60). The 5-year actuarial bNED rate was 77%. Acute GU and GI morbidity G1-2 were seen in 17.8% and 7.1% of patients, respectively. Late G1 or G2 GU morbidity was seen in 10.7% of the patients, while late G3 morbidity was observed in 7.1% of the patients, represented by urethral strictures. Conclusion: this group of patients had similar bNED rates when compared to literature, with acceptable morbidity rates. (author)

  3. Radiations

    International Nuclear Information System (INIS)

    Pujol Mora, J.

    1999-01-01

    The exposition to ionizing radiations is a constant fact in the life of the human being and its utilization as diagnostic and therapeutic method is generalized. However, it is notorious how as years go on, the fear to the ionizing radiation seems to persist too, and this fact is not limited to the common individual, but to the technical personnel and professional personnel that labors with them same. (S. Grainger) [es

  4. Radiation

    International Nuclear Information System (INIS)

    Davidson, J.H.

    1986-01-01

    The basic facts about radiation are explained, along with some simple and natural ways of combating its ill-effects, based on ancient healing wisdom as well as the latest biochemical and technological research. Details are also given of the diet that saved thousands of lives in Nagasaki after the Atomic bomb attack. Special comment is made on the use of radiation for food processing. (U.K.)

  5. The radiation swelling effect on fracture properties and fracture mechanisms of irradiated austenitic steels. Part II. Fatigue crack growth rate

    Energy Technology Data Exchange (ETDEWEB)

    Margolin, B., E-mail: margolinbz@yandex.ru; Minkin, A.; Smirnov, V.; Sorokin, A.; Shvetsova, V.; Potapova, V.

    2016-11-15

    The experimental data on the fatigue crack growth rate (FCGR) have been obtained for austenitic steel of 18Cr-10Ni-Ti grade (Russian analog of AISI 321 steel) irradiated up to neutron dose of 150 dpa with various radiation swelling. The performed study of the fracture mechanisms for cracked specimens under cyclic loading has explained why radiation swelling affects weakly FCGR unlike its effect on fracture toughness. Mechanical modeling of fatigue crack growth has been carried out and the dependencies for prediction of FCGR in irradiated austenitic steel with and with no swelling are proposed and verified with the obtained experimental results. As input data for these dependencies, FCGR for unirradiated steel and the tensile mechanical properties for unirradiated and irradiated steels are used.

  6. Development of 'Dose Rate Meter' android app for radiation detection using camera of smartphones and tablet

    International Nuclear Information System (INIS)

    Shaikh, Aatef; Sharma, M.K.; Kulkarni, M.S.; Romal, Jis; Gupta, A.; Chaudhury, P.

    2018-01-01

    An android app 'Dose Rate Meter' for gamma radiation field measurement over wide range using smart phone has been developed. The android app implements the cluster counting and high delta algorithm. The high delta algorithm processes multiple images captured by the camera. It is more sensitive at lower dose rates but it saturates at higher dose rates of the order of 1Gy/h and its response starts decreasing. Since, this algorithm analyses a number of images to compute the dose rate, it takes few minutes to process on a typical smart phone with 1 GB RAM, dual core processor and a clock in the range of 1GHz. However, the cluster count algorithm computes the results in a few seconds only as it operates on a single image but it can be used to measure dose rate only in the range of 5 mGy/h and above. Therefore, we have implemented the two algorithms in such a way that initially, the control goes to the cluster count algorithm and in case the dose rate is below 5mGy/h, it has provision to invoke the high delta algorithm, thereby covering a dose rate measurement range from μGy/h to Gy/h

  7. On the influence of the ventilation rate to the radiation burden in dwellings

    International Nuclear Information System (INIS)

    Tschurlovits, M.

    1980-01-01

    Calculations on the influence of the ventilation rate to the concentration of radon in dwellings from radioactive material of natural origin in building material are completed with a few examples of measurements. In addition, the optimization of the ventilation rate and the consequences of poorly ventilated dwellings are reported briefly. (author)

  8. Preliminary results of concurrent chemotherapy and radiation therapy using high-dose-rate brachytherapy for cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Ja; Lee, Ji Hye; Lee, Re Na; Suh, Hyun Suk [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

    2006-09-15

    To determine the efficacy and safety of concurrent chemotherapy and radiation therapy with high-dose-rate brachytherapy for cervical cancer. From January 2001 to December 2002, 30 patients with cervical cancer were treated with concurrent chemotherapy (cisplatin and 5-FU) and definitive radiation therapy. The median age was 58 (range 34 {approx} 74) year old. The pathology of the biopsy sections was squamous cell carcinoma in 29 patients and one was adenocarcinoma. The distribution to FIGO staging system was as follow: stage IB, 7 (23%); IIA, 3 (10%); IIB, 12 (40%); IIIA, 3 (10%); IIIB, 5 (17%). All patients received pelvic external beam irradiation (EBRT) to a total dose of 45 {approx} 50.4 Gy (median: 50.4 Gy) over 5 {approx} 5.5 weeks. Ir-192 HDR intracavity brachytherapy (ICBT) was given after a total dose of 41.1 Gy. HDR-ICBT was performed twice a week, with a fraction point. A dose of 4 Gy and median dose to point A was 28 Gy (range: 16 {approx} 32 Gy) in 7 fractions. The median cumulative biologic effective dose (BED) at point A (EBRT + ICBT) was 88 Gy{sub 10} (range:77 {approx} 94 Gy{sub 10}). The median cumulative BED at ICRU 38 reference point (EBRT + ICBT) was 131 Gy{sub 3} (range: 122 {approx} 140 Gy{sub 3}) at point A, 109 Gy{sub 3} (range:88{approx} 125 Gy{sub 3}) at the rectum and 111 Gy{sub 3} (range: 91 {approx} 123 Gy{sub 3}) at the urinary bladder. Cisplatin (60 mg/m{sup 2}) and 5-FU (1,000 mg/m{sup 2}) was administered intravenously at 2 weeks interval from the first day of radiation for median 5 (range:2 {approx} 6) cycles. The assessment was performed at 1 month after completion of radiation therapy by clinical examination and CT scan. The median follow-up time was 36 months (range:8{approx} 50 months). The complete response rate after concurrent chemo radiation therapy was 93.3%. The 3-yr actuarial pelvic control rate was 87% and 3-yr actuarial overall survival and disease-free survival rate was 93% and 87%, respectively. The local failure

  9. Preliminary results of concurrent chemotherapy and radiation therapy using high-dose-rate brachytherapy for cervical cancer

    International Nuclear Information System (INIS)

    Lee, Kyung Ja; Lee, Ji Hye; Lee, Re Na; Suh, Hyun Suk

    2006-01-01

    To determine the efficacy and safety of concurrent chemotherapy and radiation therapy with high-dose-rate brachytherapy for cervical cancer. From January 2001 to December 2002, 30 patients with cervical cancer were treated with concurrent chemotherapy (cisplatin and 5-FU) and definitive radiation therapy. The median age was 58 (range 34 ∼ 74) year old. The pathology of the biopsy sections was squamous cell carcinoma in 29 patients and one was adenocarcinoma. The distribution to FIGO staging system was as follow: stage IB, 7 (23%); IIA, 3 (10%); IIB, 12 (40%); IIIA, 3 (10%); IIIB, 5 (17%). All patients received pelvic external beam irradiation (EBRT) to a total dose of 45 ∼ 50.4 Gy (median: 50.4 Gy) over 5 ∼ 5.5 weeks. Ir-192 HDR intracavity brachytherapy (ICBT) was given after a total dose of 41.1 Gy. HDR-ICBT was performed twice a week, with a fraction point. A dose of 4 Gy and median dose to point A was 28 Gy (range: 16 ∼ 32 Gy) in 7 fractions. The median cumulative biologic effective dose (BED) at point A (EBRT + ICBT) was 88 Gy 10 (range:77 ∼ 94 Gy 10 ). The median cumulative BED at ICRU 38 reference point (EBRT + ICBT) was 131 Gy 3 (range: 122 ∼ 140 Gy 3 ) at point A, 109 Gy 3 (range:88∼ 125 Gy 3 ) at the rectum and 111 Gy 3 (range: 91 ∼ 123 Gy 3 ) at the urinary bladder. Cisplatin (60 mg/m 2 ) and 5-FU (1,000 mg/m 2 ) was administered intravenously at 2 weeks interval from the first day of radiation for median 5 (range:2 ∼ 6) cycles. The assessment was performed at 1 month after completion of radiation therapy by clinical examination and CT scan. The median follow-up time was 36 months (range:8∼ 50 months). The complete response rate after concurrent chemo radiation therapy was 93.3%. The 3-yr actuarial pelvic control rate was 87% and 3-yr actuarial overall survival and disease-free survival rate was 93% and 87%, respectively. The local failure rate was 13% and distant metastatic rate was 3.3%. The crude rate of minor hematologic

  10. Survey of Gamma Dose and Radon Exhalation Rate from Soil Surface of High Background Natural Radiation Areas in Ramsar, Iran

    Directory of Open Access Journals (Sweden)

    Rouhollah Dehghani

    2013-09-01

    Full Text Available Background: Radon is a radioactive gas and the second leading cause of death due to lung cancer after smoking. Ramsar is known for having the highest levels of natural background radiation on earth. Materials and Methods: In this research study, 50 stations of high radioactivity areas of Ramsar were selected in warm season of the year. Then gamma dose and radon exhalation rate were measured.Results: Results showed that gamma dose and radon exhalation rate were in the range of 51-7100 nSv/hr and 9-15370 mBq/m2s, respectively.Conclusion: Compare to the worldwide average 16 mBq/m2s, estimated average annual effective of Radon exhalation rate in the study area is too high.

  11. Mimicking the effects of spaceflight on bone: Combined effects of disuse and chronic low-dose rate radiation exposure on bone mass in mice

    Science.gov (United States)

    Yu, Kanglun; Doherty, Alison H.; Genik, Paula C.; Gookin, Sara E.; Roteliuk, Danielle M.; Wojda, Samantha J.; Jiang, Zhi-Sheng; McGee-Lawrence, Meghan E.; Weil, Michael M.; Donahue, Seth W.

    2017-11-01

    During spaceflight, crewmembers are subjected to biomechanical and biological challenges including microgravity and radiation. In the skeleton, spaceflight leads to bone loss, increasing the risk of fracture. Studies utilizing hindlimb suspension (HLS) as a ground-based model of spaceflight often neglect the concomitant effects of radiation exposure, and even when radiation is accounted for, it is often delivered at a high-dose rate over a very short period of time, which does not faithfully mimic spaceflight conditions. This study was designed to investigate the skeletal effects of low-dose rate gamma irradiation (8.5 cGy gamma radiation per day for 20 days, amounting to a total dose of 1.7 Gy) when administered simultaneously to disuse from HLS. The goal was to determine whether continuous, low-dose rate radiation administered during disuse would exacerbate bone loss in a murine HLS model. Four groups of 16 week old female C57BL/6 mice were studied: weight bearing + no radiation (WB+NR), HLS + NR, WB + radiation exposure (WB+RAD), and HLS+RAD. Surprisingly, although HLS led to cortical and trabecular bone loss, concurrent radiation exposure did not exacerbate these effects. Our results raise the possibility that mechanical unloading has larger effects on the bone loss that occurs during spaceflight than low-dose rate radiation.

  12. Interannual Variability in Radiative Forcing and Snowmelt Rates by Desert Dust in Snowcover in the Colorado River Basin

    Science.gov (United States)

    Skiles, S.; Painter, T. H.; Barrett, A. P.; Landry, C.; Deems, J. S.; Winstral, A. H.

    2010-12-01

    Dust in snow accelerates snowmelt through its direct reduction of albedo and its further reduction of albedo by accelerating the growth of snow effective grain size. Since the Anglo expansion and disturbance of the western US that began in the mid 19th century, the mountain snow cover of the Colorado River Basin has been subject to five-fold greater dust loading. This research expands on the work done in Painter et al. (2007) by assessing the interannual variability in radiative forcing, melt rates, and shortening of snow cover duration from 2005 to 2010, and the relative response of melt rates to simulated increases in air temperature. We ran the SNOBAL snowmelt model over the 6 year energy balance record at the alpine and subalpine towers in the Senator Beck Basin Study Area, San Juan Mountains, Colorado, USA. Observations indicate that dust concentrations are not correlated with total number of dust events and that dust loading and concentrations vary by an order of magnitude during the 6 year record. Our modeling results indicate that the number of days that dust advances retreat of snow cover and cumulative radiative forcing are linearly related to total dust concentration. Over the 6 years of record we have shown that for all years dust advances melt relative to a clean snowpack, even in lowest dust concentration years melt is advanced by up to 26 days. The greatest dust radiative impact occurred in 2009, when snow cover duration was shortened by 50 days, and the highest observed end of year dust concentrations reduced visible albedo to less than 0.35 during the last three weeks of snowcover. This work also shows that dust radiative forcing has a markedly greater impact on snow cover duration than increases in temperature. In the presence of dust there is little impact from temperature increases of 2 °C and 4 °C (0-4 days) and, in the absence of dust radiative forcing, temperature increases shorten snow cover duration by 5-18 days, compared with the 26

  13. Mapping radon-prone areas using γ-radiation dose rate and geological information

    International Nuclear Information System (INIS)

    García-Talavera, M; Rey, C; Ramos, L; García-Pérez, A

    2013-01-01

    Identifying radon-prone areas is key to policies on the control of this environmental carcinogen. In the current paper, we present the methodology followed to delineate radon-prone areas in Spain. It combines information from indoor radon measurements with γ-radiation and geological maps. The advantage of the proposed approach is that it lessens the requirement for a high density of measurements by making use of commonly available information. It can be applied for an initial definition of radon-prone areas in countries committed to introducing a national radon policy or to improving existing radon maps in low population regions. (paper)

  14. CMOS pixel sensors on high resistive substrate for high-rate, high-radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Hirono, Toko, E-mail: thirono@uni-bonn.de [Physikalisches Institute der Universität Bonn, Bonn (Germany); Barbero, Marlon; Breugnon, Patrick; Godiot, Stephanie [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Gonella, Laura; Hemperek, Tomasz; Hügging, Fabian; Krüger, Hans [Physikalisches Institute der Universität Bonn, Bonn (Germany); Liu, Jian; Pangaud, Patrick [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Peric, Ivan [IPE, Karlsruher Institut für Technologie, Karlsruhe (Germany); Pohl, David-Leon [Physikalisches Institute der Universität Bonn, Bonn (Germany); Rozanov, Alexandre [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Rymaszewski, Piotr [Physikalisches Institute der Universität Bonn, Bonn (Germany); Wang, Anqing [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Wermes, Norbert [Physikalisches Institute der Universität Bonn, Bonn (Germany)

    2016-09-21

    A depleted CMOS active pixel sensor (DMAPS) has been developed on a substrate with high resistivity in a high voltage process. High radiation tolerance and high time resolution can be expected because of the charge collection by drift. A prototype of DMAPS was fabricated in a 150 nm process by LFoundry. Two variants of the pixel layout were tested, and the measured depletion depths of the variants are 166 μm and 80 μm. We report the results obtained with the prototype fabricated in this technology.

  15. Brachytherapy - not pulsed and low rate brachytherapy. Medical radiation protection - ED 4248

    International Nuclear Information System (INIS)

    2008-06-01

    After an indication of authorizations required to perform brachytherapy, this sheet indicates the concerned personnel, indicates the different treatment steps, briefly describes the risk related to ionizing radiations, indicates the various aspects of risk assessment and of determination of exposure levels (definition of controlled and monitored areas, personnel classification, possible methods for dose monitoring), presents the strategy for risk management (rules regarding risk reduction, technical measures regarding the installation, individual technical measures, training and information, prevention and medical monitoring) and how this risk management can be assessed

  16. Enhanced low dose rate radiation effect test on typical bipolar devices

    International Nuclear Information System (INIS)

    Liu Minbo; Chen Wei; Yao Zhibin; He Baoping; Huang Shaoyan; Sheng Jiangkun; Xiao Zhigang; Wang Zujun

    2014-01-01

    Two types of bipolar transistors and nine types bipolar integrated circuit were selected in the irradiation experiment at different "6"0Co γ dose rate. The base current of bipolar transistor and input bias current of amplifier and comparator was measured, low dose enhance factor of test device was obtained. The results show that bipolar device have enhanced low dose rate sensitivity, enhancement factor of bipolar integrated circuit was bigger than that of transistor, and enhanced low dose rate sensitivity greatly varied with different structure and process of bipolar device. (authors)

  17. Shipwreck rates reveal Caribbean tropical cyclone response to past radiative forcing.

    Science.gov (United States)

    Trouet, Valerie; Harley, Grant L; Domínguez-Delmás, Marta

    2016-03-22

    Assessing the impact of future climate change on North Atlantic tropical cyclone (TC) activity is of crucial societal importance, but the limited quantity and quality of observational records interferes with the skill of future TC projections. In particular, North Atlantic TC response to radiative forcing is poorly understood and creates the dominant source of uncertainty for twenty-first-century projections. Here, we study TC variability in the Caribbean during the Maunder Minimum (MM; 1645-1715 CE), a period defined by the most severe reduction in solar irradiance in documented history (1610-present). For this purpose, we combine a documentary time series of Spanish shipwrecks in the Caribbean (1495-1825 CE) with a tree-growth suppression chronology from the Florida Keys (1707-2009 CE). We find a 75% reduction in decadal-scale Caribbean TC activity during the MM, which suggests modulation of the influence of reduced solar irradiance by the cumulative effect of cool North Atlantic sea surface temperatures, El Niño-like conditions, and a negative phase of the North Atlantic Oscillation. Our results emphasize the need to enhance our understanding of the response of these oceanic and atmospheric circulation patterns to radiative forcing and climate change to improve the skill of future TC projections.

  18. Measurement of radiocesium concentration in trees using cumulative gamma radiation dose rate detection systems - A simple presumption for radiocesium concentration in living woods using glass-badge based gamma radiation dose rate detection system

    Energy Technology Data Exchange (ETDEWEB)

    Yoshihara, T.; Hashida, S.N. [Plant Molecular Biology, Laboratory of Environmental Science, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba 270-1194 (Japan); Kawachi, N.; Suzui, N.; Yin, Y.G.; Fujimaki, S. [Radiotracer Imaging Gr., Quantum Beam Science Center, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Nagao, Y.; Yamaguchi, M. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2014-07-01

    Radiocesium from the severe accident at the Fukushima Dai-ichi Nuclear Power Plant on 11 March 2011 contaminates large areas. After this, a doubt for forest products, especially of mushroom, is indelible at the areas. Pruned woody parts and litters are containing a considerable amount of radiocesium, and generates a problem at incineration and composting. These mean that more attentive survey for each subject is expected; however, the present survey system is highly laborious/expensive and/or non-effective for this purpose. On the other hand, we can see a glass-badge based gamma radiation dose rate detection system. This system always utilized to detect a personal cumulative radiation dose, and thus, it is not suitable to separate a radiation from a specific object. However, if we can separate a radiation from a specific object and relate it with the own radiocesium concentration, it would enable us to presume the specific concentration with just an easy monitoring but without a destruction of the target nature and a complicated process including sampling, pre-treatment, and detection. Here, we present the concept of the measurement and results of the trials. First, we set glass-badges (type FS, Chiyoda Technol Corp., Japan) on a part of bough (approximately 10 cm in diameter) of Japanese flowering cherry trees (Prunus x yedoensis cv. Somei-Yoshino) with four different settings: A, a direct setting without any shield; B, a setting with an aluminum shield between bough and the glass-badge; C, a setting with a lead shield between bough and the glass-badge; D, a setting with a lead shield covering the glass-badge to shut the radiation from the surrounding but from bough. The deduction between the amount of each setting should separate a specific radiation of the bough from unlimited radiation from the surrounding. Even if the hourly dose rate is not enough to count the difference, a moderate cumulative dose would clear the difference. In fact, results demonstrated a

  19. Environmental gamma dose rate monitoring along Mumbai-Pune route using environmental radiation monitor with navigational aid

    International Nuclear Information System (INIS)

    Padmanabhan, N.; Kale, M.S.; Raman, N.; Krishnamachari, G.; Harikumar, M.; Sharma, D.N.; Mehta, S.K.

    1997-01-01

    A continuous environmental radiation monitor with navigational aid (ERMNA) for mapping natural gamma radiation background on country wide scale by deployment in railway coaches, has been designed. The system makes use of Indian railway network which is one of the widest network of railways in the world covering nearly complete length and breadth of the country. The system uses an energy compensated (within ± 30%) GN detectors for measurement of environmental dose rate due to natural background, a global positioning system (GPS) for on-line acquisition of positional co-ordinates (longitude and latitude) and an 8085 based data acquisition and processing unit. This system is deployed in guard's cabin of a train. The dose rate data tagged with positional co-ordinates and collected by the system during train journey is down loaded into a Lap Top PC for storage, analysis and graphical representation. The system has been used for background monitoring between Mumbai and Pune. The dose rates recorded over a period of three months ranging from November 1996 to February 1997 along the route show no change in the values which vary from 4 μr/h to 6 μR/h along the route. It drops down to <3 μR/h within tunnels en route. (author)

  20. Effect of low-energy coherent radiation with lambda=6328 A on the survival rate of Saccharomyces cerevisial of strain 14

    International Nuclear Information System (INIS)

    Abramova, N.V.

    1978-01-01

    The effect of the continuous monochromatic coherent laser radiation on the survival rate of Saccharomyces cerevisiae of strain 14 is studied. The effect of laser radiation is judged by the change in the survival rate of the yeast culture before and after the irradiation. The decrease of the number of the yeast cells in the initial moments of the irradiation was observed as a result of the laser irradiation. Then the rapid decrease of the number of cells with time changes into their constant number. It is established that the low-energy coherent radiation decreases the survival rate by 30-40%

  1. Spherical ionization chamber of 14 liter for precise measurement of environmental radiation dose rate

    International Nuclear Information System (INIS)

    Nagaoka, Toshi; Saito, Kimiaki; Moriuchi, Shigeru

    1991-05-01

    A spherical ionization chamber of 14 liter filled with 1 atm. nitrogen gas was arranged aiming at precise measurement of dose rate due to environmental gamma rays and cosmic rays. Ionization current-dose rate conversion factor for this ionization chamber was derived from careful consideration taking into account the attenuation by chamber wall, ionization current due to alpha particles and so on. Experiments at calibrated gamma ray fields and intercomparison with NaI(Tl) scintillation detector were also performed, which confirmed this ionization chamber using the conversion factor can measure the dose rate with an error of only a few percent. This ionization chamber will be used for measurement of environmental gamma ray and cosmic ray dose rate. (author)

  2. Estimates of Radiation Dose Rates Near Large Diameter Sludge Containers in T Plant

    CERN Document Server

    Himes, D A

    2002-01-01

    Dose rates in T Plant canyon during the handling and storage of large diameter storage containers of K Basin sludge were estimated. A number of different geometries were considered from which most operational situations of interest can be constructed.

  3. Reductions in soil surface albedo as a function of biochar application rate: implications for global radiative forcing

    International Nuclear Information System (INIS)

    Verheijen, Frank G A; Bastos, Ana Catarina; Keizer, Jan Jacob; Jeffery, Simon; Van der Velde, Marijn; Penížek, Vít; Beland, Martin

    2013-01-01

    Biochar can be defined as pyrolysed (charred) biomass produced for application to soils with the aim of mitigating global climate change while improving soil functions. Sustainable biochar application to soils has been estimated to reduce global greenhouse gas emissions by 71–130 Pg CO 2 -C e over 100 years, indicating an important potential to mitigate climate change. However, these estimates ignored changes in soil surface reflection by the application of dark-coloured biochar. Through a laboratory experiment we show a strong tendency for soil surface albedo to decrease as a power decay function with increasing biochar application rate, depending on soil moisture content, biochar application method and land use. Surface application of biochar resulted in strong reductions in soil surface albedo even at relatively low application rates. As a first assessment of the implications for climate change mitigation of these biochar–albedo relationships, we applied a first order global energy balance model to compare negative radiative forcings (from avoided CO 2 emissions) with positive radiative forcings (from reduced soil surface albedos). For a global-scale biochar application equivalent to 120 t ha −1 , we obtained reductions in negative radiative forcings of 5 and 11% for croplands and 11 and 23% for grasslands, when incorporating biochar into the topsoil or applying it to the soil surface, respectively. For a lower global biochar application rate (equivalent to 10 t ha −1 ), these reductions amounted to 13 and 44% for croplands and 28 and 94% for grasslands. Thus, our findings revealed the importance of including changes in soil surface albedo in studies assessing the net climate change mitigation potential of biochar, and we discuss the urgent need for field studies and more detailed spatiotemporal modelling. (letter)

  4. Measurements of indoor and outdoor natural radiation exposure rates in model houses

    International Nuclear Information System (INIS)

    Matsuda, Hideharu; Fukaya, Mitsuharu; Minato, Susumu

    1990-01-01

    Natural gamma-ray and cosmic-ray exposure rates were measured indoors and outdoors for 94 model houses of four housing centers in Nagoya to obtain basic data for estimation of the population dose. Influence of the structure of houses on indoor exposure rates and relationship between indoor and outdoor natural gamma-ray exposure rates were studied. Exposure rates were measured with a 1.5'' φ x 4'' NaI (Tl) scintillation counter and a 6''φ spherical plastic scintillation counter. The mean indoor natural gamma-ray exposure rate in ferro-concrete buildings was about 40% higher than that in fireproof wooden houses, about 60% higher than that in light-weight steel-framed buildings, in fireproof wooden houses, it was also about 10% higher than in light-weight steel-framed building. The ratio of indoor to outdoor natural gamma-ray exposure rate was found to be about 0.95±0.15, 0.77±0.10, and 0.72±0.13 for ferro-concrete buildings, fireproof wooden houses and light-weight steel-framed buildings, respectively. The mean indoor cosmic-ray exposure rate in ferro-concrete buildings was 2.8 μR/h, about 18% lower than the outdoors. The indoor cosmic-ray exposure rate in fireproof wooden houses and light-weight steel-framed buildings were 3.2 μR/h, about 6% lower than the outdoors. (author)

  5. Measurements of natural radiation exposure rates in various living environment, (2)

    International Nuclear Information System (INIS)

    Matsuda, Hideharu

    1991-01-01

    Natural gamma-ray and cosmic-ray exposure rates were measured indoors and outdoors for 94 model houses of housing exhibition centers in Nagoya to obtain basic data for estimation of the population dose. Influence of the structure of houses on indoor exposure rates and relationship between indoor and outdoor natural gamma-ray exposure rates were studied. Exposure rates were measured with a 1.5''φ x 4''NaI(Tl) scintillation counter and a 6''φ spherical plastic scintillation counter. The mean indoor natural gamma-ray exposure rate in ferro-concrete buildings was about 40 % higher than that in fire-proof wooden houses and about 60 % higher than that in light weight steel framed buildings; that in fire-proof wooden houses was about 10 % higher than that in light weight steel framed buildings. The ratio of indoor to outdoor natural gamma-ray exposure rate was found to be 0.95 ± 0.15, 0.77 ± 0.10 and 0.72 ± 0.13 for ferro-concrete buildings, fire-proof wooden houses and light weight steel framed buildings, respectively. The mean indoor cosmic-ray exposure rate in ferro-concrete buildings was 2.8 μR/h, which was about 18 % lower than the outdoor value. The indoor cosmic-ray exposure rate both in fire-proof wooden houses and in light weight steel framed buildings were about 3.2 μR/h, which was 6 % lower than the outdoor value. (author)

  6. Three-dimensional black-blood contrast-enhanced MRI improves detection of intraluminal thrombi in patients with acute ischaemic stroke.

    Science.gov (United States)

    Jang, Won; Kwak, Hyo Sung; Chung, Gyung Ho; Hwang, Seung Bae

    2018-03-19

    This study evaluated the utility of three-dimensional (3D), black-blood (BB), contrast-enhanced, magnetic resonance imaging (MRI) for the detection of intraluminal thrombi in acute stroke patients. Forty-seven patients with acute stroke involving the anterior circulation underwent MRI examination within 6 h of clinical onset. Cerebral angiography was used as the reference standard. In a blinded manner, two neuroradiologists interpreted the following three data sets: (1) diffusion-weighted imaging (DWI) + 3D BB contrast-enhanced MRI; (2) DWI + susceptibility weighted imaging (SWI); (3) DWI + 3D BB contrast-enhanced MRI + SWI. Of these patients, 47 had clots in the middle cerebral artery and four had clots in the anterior cerebral artery. For both observers, the area under the curve (Az) for data sets 1 and 3, which included 3D BB contrast-enhanced MRI, was significantly greater than it was for data set 2, which did not include 3D BB contrast-enhanced MR imaging (observer 1, 0.988 vs 0.904, p = 0.001; observer 2, 0.988 vs 0.894, p = 0.000). Three-dimensional BB contrast-enhanced MRI improves detection of intraluminal thrombi compared to conventional MRI methods in patients with acute ischaemic stroke. • BB contrast-enhanced MRI helps clinicians to assess the intraluminal clot • BB contrast-enhanced MRI improves detection of intraluminal thrombi • BB contrast-enhanced MRI for clot detection has a higher sensitivity.

  7. Multi-Detector CT Findings of the Normal Appendix in Children: Evaluation of the Position, Diameter, and Presence or Absence of Intraluminal Gas

    Energy Technology Data Exchange (ETDEWEB)

    Park, Woon Ju; Kim, Jong Chul [Dept. of Radiology, Chungnam National University College of Medicine, Daejeon (Korea, Republic of)

    2011-08-15

    To assess the usefulness of multi-detector CT (MDCT) with multiplanar reformations (MPR) for the evaluation of the position, diameter and presence or absence of intraluminal gas in the normal appendix in children. From 2007 to 2010, we retrospectively analyzed the MDCT images of normal appendices in 133 children, and evaluated the position, diameter, and presence or absence of intraluminal gas in the appendix. Among the 133 appendices, type I (postileal and medial paracecal position) was found in 64 children, type II (subcecal position) in 22, type III (retrocecal and retrocolic/laterocolic position) in 15, type IV (preileal and medial colic position) in 16, and type V (lower pelvic position) in 16 children. The mean diameter was 5.8 mm {+-} 1.2 (SD) (range; 3.2-8.7 mm). There was a high correlation between the appendiceal diameter and age (p = 0.000).There was no statistically significant difference in the appendiceal diameter between boys and girls (p = 0.470). Intraluminal gas was found in 115 appendices and there was no statistically significant correlation between the appendiceal diameter and intraluminal gas (p = 0.502). The MDCT with MPR was useful for the evaluation of the normal appendices in children. The procedure may be useful for the diagnosis of equivocal or unusual appendicitis in children.

  8. Dose and dose-rate effects of ionizing radiation: a discussion in the light of radiological protection

    Energy Technology Data Exchange (ETDEWEB)

    Ruehm, Werner [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Radiation Protection, Neuherberg (Germany); Woloschak, Gayle E. [Northwestern University, Department of Radiation Oncology, Feinberg School of Medicine, Chicago, IL (United States); Shore, Roy E. [Radiation Effects Research Foundation (RERF), Hiroshima City (Japan); Azizova, Tamara V. [Southern Urals Biophysics Institute (SUBI), Ozyorsk, Chelyabinsk Region (Russian Federation); Grosche, Bernd [Federal Office for Radiation Protection, Oberschleissheim (Germany); Niwa, Ohtsura [Fukushima Medical University, Fukushima (Japan); Akiba, Suminori [Kagoshima University Graduate School of Medical and Dental Sciences, Department of Epidemiology and Preventive Medicine, Kagoshima City (Japan); Ono, Tetsuya [Institute for Environmental Sciences, Rokkasho, Aomori-ken (Japan); Suzuki, Keiji [Nagasaki University, Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki (Japan); Iwasaki, Toshiyasu [Central Research Institute of Electric Power Industry (CRIEPI), Radiation Safety Research Center, Nuclear Technology Research Laboratory, Tokyo (Japan); Ban, Nobuhiko [Tokyo Healthcare University, Faculty of Nursing, Tokyo (Japan); Kai, Michiaki [Oita University of Nursing and Health Sciences, Department of Environmental Health Science, Oita (Japan); Clement, Christopher H.; Hamada, Nobuyuki [International Commission on Radiological Protection (ICRP), PO Box 1046, Ottawa, ON (Canada); Bouffler, Simon [Public Health England (PHE), Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot (United Kingdom); Toma, Hideki [JAPAN NUS Co., Ltd. (JANUS), Tokyo (Japan)

    2015-11-15

    The biological effects on humans of low-dose and low-dose-rate exposures to ionizing radiation have always been of major interest. The most recent concept as suggested by the International Commission on Radiological Protection (ICRP) is to extrapolate existing epidemiological data at high doses and dose rates down to low doses and low dose rates relevant to radiological protection, using the so-called dose and dose-rate effectiveness factor (DDREF). The present paper summarizes what was presented and discussed by experts from ICRP and Japan at a dedicated workshop on this topic held in May 2015 in Kyoto, Japan. This paper describes the historical development of the DDREF concept in light of emerging scientific evidence on dose and dose-rate effects, summarizes the conclusions recently drawn by a number of international organizations (e.g., BEIR VII, ICRP, SSK, UNSCEAR, and WHO), mentions current scientific efforts to obtain more data on low-dose and low-dose-rate effects at molecular, cellular, animal and human levels, and discusses future options that could be useful to improve and optimize the DDREF concept for the purpose of radiological protection. (orig.)

  9. Energy levels and radiative rates for transitions in B-like to F-like Kr ions (Kr XXXII XXVIII)

    Science.gov (United States)

    Aggarwal, K. M.; Keenan, F. P.; Lawson, K. D.

    2008-05-01

    Energy levels, radiative rates, oscillator strengths, line strengths, and lifetimes have been calculated for transitions in B-like to F-like Kr ions, Kr XXXIII-XXVIII. For the calculations, the fully relativistic GRASP code has been adopted, and results are reported for all electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) transitions among the lowest 125, 236, 272, 226, and 113 levels of Kr XXXII, Kr XXXI, Kr XXX, Kr XXIX, and Kr XXVIII, respectively, belonging to the n ⩽ 3 configurations. Comparisons are made with earlier available theoretical and experimental results, and some discrepancies have been noted and explained.

  10. Natural terrestrial radiation exposure in Hong Kong. A survey on environmental gamma absorbed dose rate in air

    International Nuclear Information System (INIS)

    Wong, M.C.; Poon, H.T.; Chan, Y.K.; So, C.K.

    2000-01-01

    Hong Kong is a metropolitan city located on the southern coast of China with a population of some six million. About 90% of the population is concentrated in heavily built-up residential and commercial areas, which accounts for less than 50% of the total area in the territory. Hong Kong Observatory, 134A Nathan Road, Kowloon, Hong Kong, China. In order to understand the spatial variations in the environmental radiation levels in Hong Kong, the Hong Kong Observatory (HKO) in early 1999 conducted a study of the environmental gamma absorbed dose rate in air. The study combined data collected by the HKO radiation monitoring network (RMN) and data from a comprehensive territory-wide radiological survey conducted in January and February 1999. The RMN of ten stations each equipped with a Reuter-Stokes Model RSS-1013 HPIC has been in operation since 1987 to continuously monitor the environmental radiation levels over the territory as part of the emergency monitoring programme for response to nuclear accidents at a nearby nuclear power station. The terrestrial component of the environmental radiation field was estimated by subtracting from the measurements the cosmic contribution, which is determined to be about 39 nGy/h from measurements conducted over two large fresh water reservoirs. The RMN data with the long history was analysed to derive the seasonal variations in the environmental radiation levels. On average the environmental gamma absorbed dose rate in air in January and February is 1.03 times of the annual figure. This seasonal correction was applied to the results of the year 1999 survey. As the radiation field in the heavily built-up areas is enhanced by contribution from buildings, in the territory-wide survey measurements were made both in the open field and built-up areas. The territory of Hong Kong was divided into 42 grid boxes of 5 km x 5 km for open field and 61 grid boxes of 2.5 km x 2.5 km for built-up areas according to the population and land use. A

  11. Dose-rate evidence for two kinds of radiation damage in stationary-phase mammalian cells

    International Nuclear Information System (INIS)

    Metting, N.F.; Braby, L.A.; Roesch, W.C.; Nelson, J.M.

    1985-01-01

    Survival based on colony formation was measured for starved plateau-phase Chinese hamster ovary (CHO) cells exposed to 250 kVp X rays at dose rates of 0.0031, 0.025, 0.18, 0.31, and 1.00 Gy/min. A large dose-rate effect was demonstrated. Delayed plating experiments and dose response experiments following a conditioning dose, both using a dose rate of 1.00 Gy/min and plating delays of up to 48 hr, were also used to investigate the alternative repair hypotheses. There is clearly a greater change in survival in dose-rate experiments than in the other experiments. Thus the authors believe that a process which depends on the square of the concentration of initial damage, and which alters the effect of initial damage on cell survival is being observed. They have applied the damage accumulation model to separate the single-event damage from this concentration-dependent form and estimate the repair rate for the latter type to be 70 min for their CHO cells

  12. Measurements of natural radiation exposure rates in various living environments. 4

    International Nuclear Information System (INIS)

    Matsuda, Hideharu

    1993-01-01

    The absorbed dose rates in air due to the terrestrial γ-ray and the cosmic rays were measured on five subway lines in Nagoya City and in the underground shopping malls in Sakae and The Nagoya Station areas as the basic data to estimate the population dose. The mean values of the γ-ray dose rates were 36.3 ± 7.3 nGy/h and 56.1 ± 6.4 nGy/h in the subway lines and in the underground shopping malls, respectively. It is inferred that the variation in the γ-ray dose rate is mainly due to the difference in the concentration of natural radionuclides contained in the building materials of the subway tunnels and of the ceilings of the underground malls. The cosmic ray dose rates lay in the range of ca. 1/2-1/3 of the ground level value due to the shielding effect of the materials covering over the subway tunnels or the underground shopping malls. The mean value of the total dose rate for the gamma and the cosmic rays in the subway lines was about 50% and that in the underground shopping malls was about 20% lower than the value (87.3 nGy/h) on the ground in Nagoya City. (author)

  13. Study of radon progeny distribution and radiation dose rate in the atmosphere

    International Nuclear Information System (INIS)

    Fujinami, Naoto

    2009-01-01

    The absorbed dose rate in air of airborne gamma-ray and the concentration of radon progeny in surface air have been observed continuously in Maizuru, Japan. When data observed on fine days were plotted, with dose rate as ordinate and contraction as abscissa, these points traced with a lapse of time illustrated an anticlockwise looping for each day. This result suggests that the variation of absorbed dose rate lags behind that of concentration of radon progeny; this is due to the delay time incurred as the concentration level gradually varies from ground surface to upper air. Radon progeny concentrations in precipitation and in surface air have been observed there in order to study the relationship between the two concentrations and the influence of precipitation patterns on the concentration in precipitation. Results obtained from analysis of the observed data suggest that radon progeny in precipitation originate mainly from scavenging within the cloud (rainout) and not from that below the cloud (washout). (author)

  14. A study on measurement on artificial radiation dose rate using the response matrix method

    International Nuclear Information System (INIS)

    Kidachi, Hiroshi; Ishikawa, Yoichi; Konno, Tatsuya

    2004-01-01

    We examined accuracy and stability of estimated artificial dose contribution which is distinguished from natural background gamma-ray dose rate using Response Matrix method. Irradiation experiments using artificial gamma-ray sources indicated that there was a linear relationship between observed dose rate and estimated artificial dose contribution, when irradiated artificial gamma-ray dose rate was higher than about 2 nGy/h. Statistical and time-series analyses of long term data made it clear that estimated artificial contribution showed almost constant values under no artificial influence from the nuclear power plants. However, variations of estimated artificial dose contribution were infrequently observed due to of rainfall, detector maintenance operation and occurrence of calibration error. Some considerations on the factors to these variations were made. (author)

  15. Relative effect of radiation dose rate on hemopoietic and nonhemopoietic lethality of total-body irradiation

    International Nuclear Information System (INIS)

    Peters, L.J.; McNeill, J.; Karolis, C.; Thames, H.D. Jr.; Travis, E.L.

    1986-01-01

    Experiments were undertaken to determine the influence of dose rate on the toxicity of total-body irrdiation (TBI) with and without syngeneic bone-marrow rescue in mice. The results showed a much greater dose-rate dependence for death from nonhemopoietic toxicity than from bone-marrow ablation, with the ratio of LD 50 's increasing from 1.73 at 25 cGy/min to 2.80 at 1 cGy/min. At the higher dose rates, dose-limiting nonhemopoietic toxicity resulted from late organ injury, affecting the lungs, kidneys, and liver. At 1 cGy/min the major dose-limiting nonhemopoietic toxicity was acute gastrointestinal injury. The implications of these results in the context of TBI in preparation for bone-marrow transplantation are discussed. 15 refs., 4 figs

  16. A digital approach for real time high-rate high-resolution radiation measurements

    International Nuclear Information System (INIS)

    Gerardi, G.; Abbene, L.

    2014-01-01

    Modern spectrometers are currently developed by using digital pulse processing (DPP) systems, showing several advantages over traditional analog electronics. The aim of this work is to present digital strategies, in a time domain, for the development of real time high-rate high-resolution spectrometers. We propose a digital method, based on the single delay line (SDL) shaping technique, able to perform multi-parameter analysis with high performance even at high photon counting rates. A robust pulse shape and height analysis (PSHA), applied on single isolated time windows of the detector output waveforms, is presented. The potentialities of the proposed strategy are highlighted through both theoretical and experimental approaches. To strengthen our approach, the implementation of the method on a real-time system together with some experimental results are presented. X-ray spectra measurements with a semiconductor detector are performed both at low and high photon counting rates (up to 1.1 Mcps)

  17. A digital approach for real time high-rate high-resolution radiation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gerardi, G.; Abbene, L., E-mail: leonardo.abbene@unipa.it

    2014-12-21

    Modern spectrometers are currently developed by using digital pulse processing (DPP) systems, showing several advantages over traditional analog electronics. The aim of this work is to present digital strategies, in a time domain, for the development of real time high-rate high-resolution spectrometers. We propose a digital method, based on the single delay line (SDL) shaping technique, able to perform multi-parameter analysis with high performance even at high photon counting rates. A robust pulse shape and height analysis (PSHA), applied on single isolated time windows of the detector output waveforms, is presented. The potentialities of the proposed strategy are highlighted through both theoretical and experimental approaches. To strengthen our approach, the implementation of the method on a real-time system together with some experimental results are presented. X-ray spectra measurements with a semiconductor detector are performed both at low and high photon counting rates (up to 1.1 Mcps)

  18. Small volume acid reflux in gastroesophageal reflux disease patients with hiatal hernia is only detectable by pH-metry but not by multichannel intraluminal impedance.

    Science.gov (United States)

    Weigt, J; Malfertheiner, P

    2013-07-01

    Until now, it is uncertain if the so-called pH-only reflux episodes that consist of a pH drop without evidence of retrograde bolus movement in multichannel intraluminal impedance (MII) represent reflux episodes or artifacts. Hiatal hernia (HH) may allow reflux of small volumes to occur that can be detected by pH-metry but not by MII. The aim was to search for a mechanism that can explain pH-only reflux, 20 patients (12 females and 8 males, median age 52 years, interquartile range [IQR]: 40.5-60.75 years) were investigated with MII-pH off PPI. Impedance and pH-metry data were analyzed separately. The differences in detection rate of acid reflux between pH-metry and MII were correlated with the presence of HH. In an in vitro experiment, MII-pH probes were flushed with citric acid in plastic tubes of different size with capillary diameter and diameters of 2.5 mm and 4.5 mm, while recording pH values and impedance. HH was present in six patients and absent in 14 patients. In patients with HH in comparison with patients with absent HH, the difference of acid reflux detection between pH-metry and MII is significantly higher (70%, IQR: 15-88% and 3.6%, IQR: 0-31%, respectively). In vitro all simulated reflux lead to a fall in pH whereas a corresponding decrease in impedance was only recognizable in the 4.5-mm plastic tubes. Acid reflux episodes in patients with HH are more frequently detected by pH-metry than by MII. Small volume reflux that does not lead to a decrease in impedance is the likely explanation for this phenomenon. © 2012 Copyright the Authors. Journal compilation © 2012, Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

  19. Chronic low-dose-rate ionising radiation affects the hippocampal phosphoproteome in the ApoE-/- Alzheimer's mouse model

    DEFF Research Database (Denmark)

    Kempf, S. J.; Janik, Dirk; Barjaktarovic, Zarko

    2016-01-01

    Accruing data indicate that radiation-induced consequences resemble pathologies of neurodegenerative diseases such as Alzheimer's. The aim of this study was to elucidate the effect on hippocampus of chronic low-dose-rate radiation exposure (1 mGy/day or 20 mGy/day) given over 300 days with cumula...

  20. Rates and Durability of Response to Salvage Radiation Therapy Among Patients With Refractory or Relapsed Aggressive Non-Hodgkin Lymphoma

    International Nuclear Information System (INIS)

    Tseng, Yolanda D.; Chen, Yu-Hui; Catalano, Paul J.; Ng, Andrea

    2015-01-01

    Purpose: To evaluate the response rate (RR) and time to local recurrence (TTLR) among patients who received salvage radiation therapy for relapsed or refractory aggressive non-Hodgkin lymphoma (NHL) and investigate whether RR and TTLR differed according to disease characteristics. Methods and Materials: A retrospective review was performed for all patients who completed a course of salvage radiation therapy between January 2001 and May 2011 at Brigham and Women's Hospital/Dana-Farber Cancer Institute. Separate analyses were conducted for patients treated with palliative and curative intent. Predictors of RR for each subgroup were assessed using a generalized estimating equation model. For patients treated with curative intent, local control (LC) and progression-free survival were estimated with the Kaplan-Meier method; predictors for TTLR were evaluated using a Cox proportional hazards regression model. Results: Salvage radiation therapy was used to treat 110 patients to 121 sites (76 curative, 45 palliative). Salvage radiation therapy was given as part of consolidation in 18% of patients treated with curative intent. Median dose was 37.8 Gy, with 58% and 36% of curative and palliative patients, respectively, receiving 39.6 Gy or higher. The RR was high (86% curative, 84% palliative). With a median follow-up of 4.8 years among living patients, 5-year LC and progression-free survival for curative patients were 66% and 34%, respectively. Refractory disease (hazard ratio 3.3; P=.024) and lack of response to initial chemotherapy (hazard ratio 4.3; P=.007) but not dose (P=.93) were associated with shorter TTLR. Despite doses of 39.6 Gy or higher, 2-year LC was only 61% for definitive patients with refractory disease or disease that did not respond to initial chemotherapy. Conclusions: Relapsed or refractory aggressive NHL is responsive to salvage radiation therapy, and durable LC can be achieved in some cases. However, refractory disease is associated with a

  1. An explanation of efficiency droop in InGaN-based light emitting diodes: saturated radiative recombination rate at randomly distributed In-rich active areas

    International Nuclear Information System (INIS)

    Shim, Jong-In; Kim, Hyun-Sung; Shin, Dong-Soo; Yoo, Han-Youl

    2011-01-01

    We present a comprehensive model of the dependence of the internal quantum efficiency (IQE) on both the temperature and the carrier density in InGaN-based blue and green light emitting diodes (LEDs). In our model, carriers are dominantly located and recombine both radiatively and nonradiatively inside randomly distributed In-rich areas of the InGaN quantum wells (QWs). In those areas, the carrier density is very high even at a small current density. We propose that the saturated radiative recombination rate is a primary factor determining the IQE droop of InGaN based LEDs. In typical InGaN-based QWs, it is common for the total carrier recombination rate to be smaller than the carrier injection rate even at a small current density. This is mostly attributable to the saturation of the radiative recombination rate. The saturation of the radiative recombination rate increases carrier density in InGaN QWs, enlarges nonradiative carrier losses, and eventually gives rise to the large IQE droop with increasing current. We show how the radiative recombination rate saturates and the radiative recombination rate has influence on the IQE droop in InGaN-based QW LEDs.

  2. Tyrosine positron emission tomography and protein synthesis rate in pituitary adenoma: Different effects of surgery and radiation therapy

    International Nuclear Information System (INIS)

    Bergh, Alfons C.M. van den; Pruim, Jan; Links, Thera P.; Vliet, Anton M. van der; Sluiter, Wim; Wolffenbuttel, Bruce H.R.; Langendijk, Johannes A.; Hoving, Eelco W.; Dullaart, Robin P.F.

    2011-01-01

    Introduction: Positron emission tomography (PET) using amino acid tracers is able to establish biochemical tumour characterization in vivo. The use of PET in the follow-up of non-functioning pituitary adenomas (NFA) and growth hormone producing pituitary adenomas (GHA) after surgery and radiation treatment is not yet clear. Methods: To determine the value of PET before and after transsphenoidal neurosurgery in NFA and GHA, we investigated 12 patients with pituitary adenoma (9 NFA and 3 GHA) before and 4 months after surgery with magnetic resonance imaging (MRI) and tyrosine PET (TYR-PET). Three years after radiation therapy TYR-PET was used to document residual activity in 6 of these patients (4 NFA- and 2 GHA). Tumour size was quantified by computerized MRI measurements. In TYR-PET, tumour activity was assessed by computerized measurements of the hot spot and by determination of protein synthesis rate (PSR). Results: In response to surgery, MRI showed a median tumour volume reduction of 58% (P 0.30). After radiation therapy the MRI-volumes of the residual pituitary adenomas did not change but the volume of the hot spot on TYR-PET-imaging was reduced by 58% (P = 0.02), and PSR decreased in 5 of 6 patients (P = 0.12). Conclusion: Amino acid PET tumour activity is reduced parallel with MRI volume changes after surgery. The decrease in TYR-PET activity after radiation therapy, despite unaltered MRI tumour volume, supports the concept that it is possible to follow biological tumour activity with this technique. The diagnostic merit of this tracer technique, predicting pituitary adenoma re-growth, needs to be validated in a large prospective study.

  3. Fourth IRMF comparison of calibrations of portable gamma-ray dose- rate monitors 2001-2002 Ionising radiation

    CERN Document Server

    Lewis, V E

    2002-01-01

    The Ionising Radiations Metrology Forum (IRMF) organised a fourth comparison of calibrations of gamma-ray dose-rate monitors in which fifteen establishments in the UK participated. The exercise involved the circulation of three gamma-ray monitors for calibration in the fields produced using sup 1 sup 3 sup 7 Cs, sup 2 sup 4 sup 1 Am and sup 6 sup 0 Co. The instruments used were an Electra with MC 20 probe, a Mini-Instruments Mini-rad 1000 and a Siemens electronic personal dosemeter Mk 2 (EPD). The responses relative to 'true' dose equivalent rate were calculated by the individual participants and submitted to the for analysis along with details of the facilities and fields employed. Details of the estimated uncertainties were also reported. The results are compared and demonstrate generally satisfactory agreement between the participating establishments. However, the participants' treatment of uncertainties needs improvement and demonstrates a need for guidance in this area.

  4. High cloud variations with surface temperature from 2002 to 2015: Contributions to atmospheric radiative cooling rate and precipitation changes

    Science.gov (United States)

    Liu, Run; Liou, Kuo-Nan; Su, Hui; Gu, Yu; Zhao, Bin; Jiang, Jonathan H.; Liu, Shaw Chen

    2017-05-01

    The global mean precipitation is largely constrained by atmospheric radiative cooling rates (Qr), which are sensitive to changes in high cloud fraction. We investigate variations of high cloud fraction with surface temperature (Ts) from July 2002 to June 2015 and compute their radiative effects on Qr using the Fu-Liou-Gu plane-parallel radiation model. We find that the tropical mean (30°S-30°N) high cloud fraction decreases with increasing Ts at a rate of about -1.0 ± 0.34% K-1 from 2002 to 2015, which leads to an enhanced atmospheric cooling around 0.86 W m-2 K-1. On the other hand, the northern midlatitudes (30°N-60°N) high cloud fraction increases with surface warming at a rate of 1.85 ± 0.65% K-1 and the near-global mean (60°S-60°N) high cloud fraction shows a statistically insignificant decreasing trend with increasing Ts over the analysis period. Dividing high clouds into cirrus, cirrostratus, and deep convective clouds, we find that cirrus cloud fraction increases with surface warming at a rate of 0.32 ± 0.11% K-1 (0.01 ± 0.17% K-1) for the near-global mean (tropical mean), while cirrostratus and deep convective clouds decrease with surface warming at a rate of -0.02 ± 0.18% K-1 and -0.33 ± 0.18% K-1 for the near-global mean and -0.64 ± 0.23% K-1 and -0.37 ± 0.13% K-1 for the tropical mean, respectively. High cloud fraction response to feedback to Ts accounts for approximately 1.9 ± 0.7% and 16.0 ± 6.1% of the increase in precipitation per unit surface warming over the period of 2002-2015 for the near-global mean and the tropical mean, respectively.

  5. Bioassay in BALB/c mice exposed to low dose rate radiation

    Energy Technology Data Exchange (ETDEWEB)

    Km, Sung Dae; Gong, Eun Ji; Bae, Min Ji; Yang, Kwang Mo; Kim, Joong Sun [Dongnam Institute of Radiological and Medical Sciences, Suwon (Korea, Republic of)

    2012-09-15

    The present study was performed to investigate the toxicity of low-dose-rate irradiation in BALB/c mice. Twenty mice of each sex were randomly assigned to four groups of five mice each and were exposed to 0 (sham), 0.02, 0.2, or 2 Gy, equivalents to low-dose-rate irradiation to 3.49 mGy{center_dot}h{sup -1}. Urine, blood, and blood biochemistry were analyzed, and organ weight was measured. The low-dose-rate irradiation did not induce any toxicologically significant changes in mortality, clinical signs, body weight, food and water consumption, urinalysis, and serum biochemistry. However, the weights of reproductive organs including the testis, ovary, and uterus decreased in a dose-dependent manner. Irradiation at 2 Gy significantly decreased the testis, ovary, and uterus weights, but did not change the weights of other organs. There were no adverse effects on hematology in any irradiated group and only the number of neutrophils increased dose dependently. The low-dose-rate irradiation exposure did not cause adverse effects in mice at dose levels of 2 Gy or less, but the reproductive systems of male and female mice showed toxic effects.

  6. Chronical influence of radiation and lead on mutation rates in plants of Arabidopsis Thaliana (L.) Heynh

    International Nuclear Information System (INIS)

    Kryukov, V.I.; Shishkin, V.A.; Sokolenko, S.F.

    1996-01-01

    Plants of Arabidopsis thaliana were grown in a laboratory conditions on the soil (black earth, chernozem) which was polluted with a radioactive isotopes of cesium, 134+137 Cs. Increase in specific activity of samples from 217 to 1025 and 2529 Bq/kg resulted in increase of embryonic mutation rate in Arabidopsis from 8.2 to 20.2 and 51.6 % respectively. Bringing Pb 2+ in a dose of 16 mg into the soil resulted in statistically significant decrease in mutation rate. Further increase of lead concentration in radioactive soils to 32, 64, 96, 160 and 320 mg/kg resulted in growth of the mutation rates in the plants which were grown on the soil with low and middle specific activity of cesium, and in decrease of the mutation rates in the plants which were grown on the soil with high specific radioactivity. The last process apparently was connected with the intensive growth in the number of sterile seeds in the pods. 19 refs.; 2 figs.; 4 tabs

  7. Determination of x-radiation exposure rates from color television sets

    International Nuclear Information System (INIS)

    Campos, L.L.; Caldas, L.V.E.

    1988-05-01

    The exposure rates of low energy X-rays emitted from color televisions were determined by thermoluminescence using CaSO 4 :Dy + Teflon pellets. The measurements were taken at the distances of 5 cm, 2 and 3 m in front of the screens. The results were compared with those obtained for video display terminals at the same experimental conditions. (author) [pt

  8. Intraluminal occlusion of the seminal duct by laser and Histoacryl: Two non-invasive alternatives for vasectomy

    Science.gov (United States)

    Freitag, B.; Sroka, R.; Koelle, S.; Becker, A. J.; Khoder, W.; Pongratz, T.; Stief, C. G.; Trottmann, M.

    2014-03-01

    Introduction and objective: Vasectomy is a well-established method in family control. Even though it is a safe and low risk operation, this surgery is invasive and difficult to reverse. Therefore the aim of this study was to investigate new non-invasive methods for occlusion of the seminal duct. Material and Methods: Seminal duct tissue was obtained from patients (n=30) suffering from prostate cancer and therefore undergoing prostatectomy. In a first set of experiments, the seminal duct was occluded by intraluminal application of Histoacryl® (Braun Aesculap AG, Tuttlingen, Germany). In a 2nd set of experiments, endoluminal laser induced occlusion was performed. Four different laser wavelengths (1940nm, 1470nm, 1064nm, 940nm) and different sets of laser parameters (e.g. power, exposure duration, fibre diameter, energy applied) were compared. Effectiveness of occlusion of the seminal duct was proven by post-treatment irrigation flow measurement, as well as by morphological analyses. To evaluate a potential damage of the surrounding tissue, external temperature was measured using a thermometer during laser application. Results: Intraluminal application of Histoacryl® induced an immediate and complete occlusion of the seminal duct. The underlying connective tissue maintained its functional integrity after this treatment. By laser light application to a Histoacryl® block, a hole could be created into the block thus indicating the possibility of recanalization. Treatment with laser energy resulted in shrinkage of the ductal lumen. The laser application generally caused necrosis in the epithelium and induced formation of vacuoles in the underlying connective tissue. As described for endoluminal varicose treatment, this distinct local reaction might result in an intense inflammation leading to a functional occlusion of the vas deferens. Conclusions: Both laser-induced occlusion and application of Histoacryl® are fast and simple techniques which may be able to achieve a

  9. Study of the radiation levels in low dose rate brachytherapy zones of the National Institute of Neoplastic Illnesses

    International Nuclear Information System (INIS)

    Figueroa J, N.; Mora Y, B.

    2006-01-01

    The present study has as objective to evaluate the radiation levels of the Brachytherapy work areas of low dose rate (Gammateque, nurses station and of hospitalization rooms of patients RIC of 4th, 5th Floor-East) and to estimate the effective dose of the occupationally exposed personnel and the public in general. The measurements of the dose rate in these areas, were registered with a radiations monitor Inspector trademark, during a period of 60 days, without altering the routinary work conditions. The more high levels of environmental dose equivalent rate registered in the different work areas its are of 1.41 and 47.78 μSv/h rooms 1 and 2 in the Gammateque environments, in the hospitalization rooms of the 4th and 5th floor in the point 1 are of 40.77 and 23.67, μSv/h respectively and in the point 2 are of 129.19 and 39.93, μSv/h respectively, and in the nurses station of the 4th and 5th floor its are respectively of 7.62 u Sv/h and 0.45 u Sv/h. According to the carried out measurements and the permanency in the work place is possible to estimate the effective dose involved to the occupationally exposed personnel. The personnel that works in Gammateque could be receiving respectively as maximum dose 0.61 mSv/month, and the personnel that works in the nurses station of 13.17 and 0.78 mSv/year in the 4th and 5th floor. These registered differences among the two floors are due to that the 5th floor counts with the shielding systems (screen) contrary to the 4th, another of the factors is the distribution form of the patient beds RIC. We should have present that the radiation levels although in some cases it is very high, however, they are below of the permissible limits according to standards, but it is still possible to reduce even more, the radiation levels in the critical points fulfilling with the ALARA principle. (Author)