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Sample records for total dose fraction

  1. Dose rate and dose fractionation studies in total body irradiation of dogs

    International Nuclear Information System (INIS)

    Kolb, H.J.; Netzel, B.; Schaffer, E.; Kolb, H.

    1979-01-01

    Total body irradiation (TBI) with 800-900 rads and allogeneic bone marrow transplantation according to the regimen designated by the Seattle group has induced remissions in patients with otherwise refractory acute leukemias. Relapse of leukemia after bone marrow transplantation remains the major problem, when the Seattle set up of two opposing 60 Co-sources and a low dose rate is used in TBI. Studies in dogs with TBI at various dose rates confirmed observations in mice that gastrointestinal toxicity is unlike toxicity against hemopoietic stem cells and possibly also leukemic stem cells depending on the dose rate. However, following very high single doses (2400 R) and marrow infusion acute gastrointestinal toxicity was not prevented by the lowest dose rate studied (0.5 R/min). Fractionated TBI with fractions of 600 R in addition to 1200 R (1000 rads) permitted the application of total doses up to 300 R followed by marrow infusion without irreversible toxicity. 26 dogs given 2400-3000 R have been observed for presently up to 2 years with regard to delayed radiation toxicity. This toxicity was mild in dogs given single doses at a low dose rate or fractionated TBI. Fractionated TBI is presently evaluated with allogeneic transplants in the dog before being applied to leukemic patients

  2. Use of normalized total dose to represent the biological effect of fractionated radiotherapy

    International Nuclear Information System (INIS)

    Flickinger, J.C.; Kalend, A.

    1990-01-01

    There are currently a number of radiobiological models to account for the effects of dose fractionation and time. Normalized total dose (NTD) is not another new model but is a previously reported, clinically useful form in which to represent the biological effect, determined by any specific radiobiological dose-fractionation model, of a course of radiation using a single set of standardized, easily understood terminology. The generalized form of NTD reviewed in this paper describes the effect of a course of radiotherapy administered with nonstandard fractionation as the total dose of radiation in Gy that could be administered with a given reference fractionation such as 2 Gy per fraction, 5 fractions per week that would produce an equivalent biological effect (probability of complications or tumor control) as predicted by a given dose-fractionation formula. The use of normalized total dose with several different exponential and linear-quadratic dose-fraction formulas is presented. (author). 51 refs.; 1 fig.; 1 tab

  3. Use of normalized total dose to represent the biological effect of fractionated radiotherapy

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    Flickinger, J C; Kalend, A [Pittsburgh University School of Medicine (USA). Department of Radiation Oncology Pittsburg Cancer Institute (USA)

    1990-03-01

    There are currently a number of radiobiological models to account for the effects of dose fractionation and time. Normalized total dose (NTD) is not another new model but is a previously reported, clinically useful form in which to represent the biological effect, determined by any specific radiobiological dose-fractionation model, of a course of radiation using a single set of standardized, easily understood terminology. The generalized form of NTD reviewed in this paper describes the effect of a course of radiotherapy administered with nonstandard fractionation as the total dose of radiation in Gy that could be administered with a given reference fractionation such as 2 Gy per fraction, 5 fractions per week that would produce an equivalent biological effect (probability of complications or tumor control) as predicted by a given dose-fractionation formula. The use of normalized total dose with several different exponential and linear-quadratic dose-fraction formulas is presented. (author). 51 refs.; 1 fig.; 1 tab.

  4. Marrow toxicity of fractionated vs. single dose total body irradiation is identical in a canine model

    International Nuclear Information System (INIS)

    Storb, R.; Raff, R.F.; Graham, T.; Appelbaum, F.R.; Deeg, H.J.; Schuening, F.G.; Shulman, H.; Pepe, M.

    1993-01-01

    The authors explored in dogs the marrow toxicity of single dose total body irradiation delivered from two opposing 60 Co sources at a rate of 10 cGy/min and compared results to those seen with total body irradiation administered in 100 cGy fractions with minimum interfraction intervals of 6 hr. Dogs were not given marrow transplants. They found that 200 cGy single dose total body irradiation was sublethal, with 12 of 13 dogs showing hematopoietic recovery and survival. Seven of 21 dogs given 300 cGy single dose total body irradiation survived compared to 6 of 10 dogs given 300 cGy fractionated total body irradiation. One of 28 dogs given 400 cGy single dose total body irradiation survived compared to none of six given fractionated radiation. With granulocyte colony stimulating factor (GCSF) administered from day 0-21 after 400 cGy total body irradiation, most dogs survived with hematological recovery. Because of the almost uniform success with GCSF after 400 cGy single dose total body irradiation, a study of GCSF after 400 cGy fractionated total body irradiation was deemed not to be informative and, thus, not carried out. Additional comparisons between single dose and fractionated total body irradiation were carried out with GCSF administered after 500 and 600 cGy of total body irradiation. As with lower doses of total body irradiation, no significant survival differences were seen between the two modes of total body irradiation, and only 3 of 26 dogs studied survived with complete hematological recovery. Overall, therefore, survival among dogs given single dose total body irradiation was not different from that of dogs given fractionated total body irradiation (p = .67). Similarly, the slopes of the postirradiation declines of granulocyte and platelet counts and the rates of their recovery in surviving dogs given equal total doses of single versus fractionated total body irradiation were indistinguishable. 24 refs., 3 figs., 2 tabs

  5. Impact of radiation technique, radiation fraction dose, and total cisplatin dose on hearing. Retrospective analysis of 29 medulloblastoma patients

    International Nuclear Information System (INIS)

    Scobioala, Sergiu; Kittel, Christopher; Ebrahimi, Fatemeh; Wolters, Heidi; Eich, Hans Theodor; Parfitt, Ross; Matulat, Peter; Am Zehnhoff-Dinnesen, Antoinette

    2017-01-01

    To analyze the incidence and degree of sensorineural hearing loss (SNHL) resulting from different radiation techniques, fractionation dose, mean cochlear radiation dose (D mean ), and total cisplatin dose. In all, 29 children with medulloblastoma (58 ears) with subclinical pretreatment hearing thresholds participated. Radiotherapy (RT) and cisplatin had been applied sequentially according to the HIT MED Guidance. Audiological outcomes up to the latest follow-up (median 2.6 years) were compared. Bilateral high-frequency SNHL was observed in 26 patients (90%). No significant differences were found in mean hearing threshold between left and right ears at any frequency. A significantly better audiological outcome (p < 0.05) was found after tomotherapy at the 6 kHz bone-conduction threshold (BCT) and left-sided 8 kHz air-conduction threshold (ACT) than after a combined radiotherapy technique (CT). Fraction dose was not found to have any impact on the incidence, degree, and time-to-onset of SNHL. Patients treated with CT had a greater risk of SNHL at high frequencies than tomotherapy patients even though D mean was similar. Increase in severity of SNHL was seen when the total cisplatin dose reached above 210 mg/m 2 , with the highest abnormal level found 8-12 months after RT regardless of radiation technique or fraction dose. The cochlear radiation dose should be kept as low as possible in patients who receive simultaneous cisplatin-based chemotherapy. The risk of clinically relevant HL was shown when D mean exceeds 45 Gy independent of radiation technique or radiation regime. Cisplatin ototoxicity was shown to have a dose-dependent effect on bilateral SNHL, which was more pronounced in higher frequencies. (orig.) [de

  6. Impact of radiation technique, radiation fraction dose, and total cisplatin dose on hearing. Retrospective analysis of 29 medulloblastoma patients

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    Scobioala, Sergiu; Kittel, Christopher; Ebrahimi, Fatemeh; Wolters, Heidi; Eich, Hans Theodor [University Hospital of Muenster, Department of Radiotherapy and Radiooncology, Muenster (Germany); Parfitt, Ross; Matulat, Peter; Am Zehnhoff-Dinnesen, Antoinette [University Hospital of Muenster, Department of Phoniatrics and Pediatric Audiology, Muenster (Germany)

    2017-11-15

    To analyze the incidence and degree of sensorineural hearing loss (SNHL) resulting from different radiation techniques, fractionation dose, mean cochlear radiation dose (D{sub mean}), and total cisplatin dose. In all, 29 children with medulloblastoma (58 ears) with subclinical pretreatment hearing thresholds participated. Radiotherapy (RT) and cisplatin had been applied sequentially according to the HIT MED Guidance. Audiological outcomes up to the latest follow-up (median 2.6 years) were compared. Bilateral high-frequency SNHL was observed in 26 patients (90%). No significant differences were found in mean hearing threshold between left and right ears at any frequency. A significantly better audiological outcome (p < 0.05) was found after tomotherapy at the 6 kHz bone-conduction threshold (BCT) and left-sided 8 kHz air-conduction threshold (ACT) than after a combined radiotherapy technique (CT). Fraction dose was not found to have any impact on the incidence, degree, and time-to-onset of SNHL. Patients treated with CT had a greater risk of SNHL at high frequencies than tomotherapy patients even though D{sub mean} was similar. Increase in severity of SNHL was seen when the total cisplatin dose reached above 210 mg/m{sup 2}, with the highest abnormal level found 8-12 months after RT regardless of radiation technique or fraction dose. The cochlear radiation dose should be kept as low as possible in patients who receive simultaneous cisplatin-based chemotherapy. The risk of clinically relevant HL was shown when D{sub mean} exceeds 45 Gy independent of radiation technique or radiation regime. Cisplatin ototoxicity was shown to have a dose-dependent effect on bilateral SNHL, which was more pronounced in higher frequencies. (orig.) [German] Analyse von Inzidenz und Schweregrad einer sensorineuralen Schwerhoerigkeit (''sensorineural hearing loss'', SNHL) infolge der Wirkung unterschiedlicher Bestrahlungstechniken, Fraktionierungen, mittlerer

  7. Fractionated total body irradiation and autologous bone marrow transplantation in dogs: Hemopoietic recovery after various marrow cell doses

    International Nuclear Information System (INIS)

    Bodenburger, U.; Kolb, H.J.; Thierfelder, S.; Netzel, B.; Schaeffer, E.; Kolb, H.

    1980-01-01

    Hemopoietic recovery was studied in dogs given 2400 R fractionated total body irradiation within one week and graded doses of cryopreserved autologous bone marrow. Complete hemopoietic recovery including histology was observed after this dose and sufficient doses of marrow cells. Doses of more than 5.5 x 10 7 mononuclear marrow cells/kg body weight were sufficient for complete recovery in all dogs, 1.5 to 5.5 x 10 7 cells/kg were effective in some of the dogs and less than 1.5 x 10 7 cells/kg were insufficient for complete recovery. Similarly, more than 30000 CFUsub(c)/kg body weight were required for hemopoietic recovery. The optimal marrow cell dose which has been defined as the minimal dose required for the earliest possible recovery of leukocyte and platelet counts was 7-8 x 10 7 mononuclear marrow cells/kg body weight. It has been concluded that fractionated total body irradiation with 2400 R dose not require greater doses of marrow cells for hemopoietic reconstitution than lower single doses and that the hemopoietic microenvironment is not persistently disturbed after this dose. (author)

  8. Radiobiological basis of total body irradiation with different dose rate and fractionation: repair capacity of hemopoietic cells

    International Nuclear Information System (INIS)

    Song, C.W.; Kim, T.H.; Khan, F.M.; Kersey, J.H.; Levitt, S.H.

    1981-01-01

    Total body irradiation (TBI) followed by bone marrow transplantation is being used in the treatment of malignant or non-malignant hemopoietic disorders. It has been believed that the ability of hemopoietic cells to repair sublethal radiation damage is negligible. Therefore, several schools of investigators suggested that TBI in a single exposure at extremely low dose rate (5 rad/min) over several hours, or in several fractions in 2-3 days, should yield a higher therapeutic gain, as compared with a single exposure at a high dose rate (26 rad/min). We reviewed the existing data in the literature, in particular, the response of hemopoietic cells to fractionated doses of irradiation and found that the repair capacity of both malignant and non-malignant hemopoietic cells might be greater than has been thought. It is concluded that we should not underestimate the ability of hemopoietic cells to repair sublethal radiation damage in using TBI

  9. High-dose total-body irradiation and autologous marrow reconstitution in dogs: dose-rate-related acute toxicity and fractionation-dependent long-term survival

    International Nuclear Information System (INIS)

    Deeg, H.J.; Storb, R.; Weiden, P.L.; Schumacher, D.; Shulman, H.; Graham, T.; Thomas, E.D.

    1981-01-01

    Beagle dogs treated by total-body irradiation (TBI) were given autologous marrow grafts in order to avoid death from marrow toxicity. Acute and delayed non-marrow toxicities of high single-dose (27 dogs) and fractionated TBI (20 dogs) delivered at 0.05 or 0.1 Gy/min were compared. Fractionated TBI was given in increments of 2 Gy every 6 hr for three increments per day. Acute toxicity and early mortality (<1 month) at identical total irradiation doses were comparable for dogs given fractionated or single-dose TBI. With single-dose TBI, 14, 16, and 18 Gy, respectively, given at 0.05 Gy/min, 0/5, 5/5, and 2/2 dogs died from acute toxicity; with 10, 12, and 14 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 5/5 dogs died acutely. With fractionated TBI, 14 and 16 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 2/2 dogs died auctely. Early deaths were due to radiation enteritis with or without associated septicemia (29 dogs; less than or equal to Day 10). Three dogs given 10 Gy of TBI at 0.1 Gy/min died from bacterial pneumonia; one (Day 18) had been given fractionated and two (Days 14, 22) single-dose TBI. Fifteen dogs survived beyond 1 month; eight of these had single-dose TBI (10-14 Gy) and all died within 7 months of irradiation from a syndrome consisting of hepatic damage, pancreatic fibrosis, malnutrition, wasting, and anemia. Seven of the 15 had fractionated TBI, and only one (14 Gy) died on Day 33 from hepatic failure, whereas 6 (10-14 Gy) are alive and well 250 to 500 days after irradiation. In conclusion, fractionated TBI did not offer advantages over single-dose TBI with regard to acute toxicity and early mortality; rather, these were dependent upon the total dose of TBI. The total acutely tolerated dose was dependent upon the exposure rate; however, only dogs given fractionated TBI became healthy long-term survivors

  10. nduced hyperlipidemic rats. Methods: Column chromatographic fractionation of butanol fraction of total methanol extract of leaves of Bauhinia variegata (Linn. yields four sub-fractions (sub-fraction A-D. All sub-fractions tested for their anti-hyperlipidemic activity. Sub-fractions administered at a dose of 65 mg/kg (oral to the Triton WR-1339 induced hyperlipidemic rats and total cholesterol, triglycerides, HDL, LDL and VLDL

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    Deepak Kumar

    2012-10-01

    Full Text Available Objective: To investigate the effect and evaluation of Anti-hyperlipidemic activity guided subfraction isolated from total methanolic extract of Bauhinia variegata (Linn. leaves on Triton WR-1339 induced hyperlipidemic rats. Methods: Column chromatographic fractionation of butanol fraction of total methanol extract of leaves of Bauhinia variegata (Linn. yields four subfractions (sub-fraction A-D. All sub-fractions tested for their anti-hyperlipidemic activity. Subfractions administered at a dose of 65 mg/kg (oral to the Triton WR-1339 induced hyperlipidemic rats and total cholesterol, triglycerides, HDL, LDL and VLDL level in the blood were checked. Results: Sub-fraction D showed significant reduction (P<0.05 among four sub-fraction in comparison with standard drug fenofibrate. Conclusions: From the above study it could be concluded that butanol sub-fraction D of Bauhinia variegata (Linn. not only have resulted in significant reduction in cholesterol, triglyceride, LDL, VLDL level but also increases the HDL level at a reduced dose level.

  11. Radiation-induced rib fracture after stereotactic body radiotherapy with a total dose of 54-56 Gy given in 9-7 fractions for patients with peripheral lung tumor: impact of maximum dose and fraction size.

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    Aoki, Masahiko; Sato, Mariko; Hirose, Katsumi; Akimoto, Hiroyoshi; Kawaguchi, Hideo; Hatayama, Yoshiomi; Ono, Shuichi; Takai, Yoshihiro

    2015-04-22

    Radiation-induced rib fracture after stereotactic body radiotherapy (SBRT) for lung cancer has been recently reported. However, incidence of radiation-induced rib fracture after SBRT using moderate fraction sizes with a long-term follow-up time are not clarified. We examined incidence and risk factors of radiation-induced rib fracture after SBRT using moderate fraction sizes for the patients with peripherally located lung tumor. During 2003-2008, 41 patients with 42 lung tumors were treated with SBRT to 54-56 Gy in 9-7 fractions. The endpoint in the study was radiation-induced rib fracture detected by CT scan after the treatment. All ribs where the irradiated doses were more than 80% of prescribed dose were selected and contoured to build the dose-volume histograms (DVHs). Comparisons of the several factors obtained from the DVHs and the probabilities of rib fracture calculated by Kaplan-Meier method were performed in the study. Median follow-up time was 68 months. Among 75 contoured ribs, 23 rib fractures were observed in 34% of the patients during 16-48 months after SBRT, however, no patients complained of chest wall pain. The 4-year probabilities of rib fracture for maximum dose of ribs (Dmax) more than and less than 54 Gy were 47.7% and 12.9% (p = 0.0184), and for fraction size of 6, 7 and 8 Gy were 19.5%, 31.2% and 55.7% (p = 0.0458), respectively. Other factors, such as D2cc, mean dose of ribs, V10-55, age, sex, and planning target volume were not significantly different. The doses and fractionations used in this study resulted in no clinically significant rib fractures for this population, but that higher Dmax and dose per fraction treatments resulted in an increase in asymptomatic grade 1 rib fractures.

  12. Radiation-induced rib fracture after stereotactic body radiotherapy with a total dose of 54–56 Gy given in 9–7 fractions for patients with peripheral lung tumor: impact of maximum dose and fraction size

    International Nuclear Information System (INIS)

    Aoki, Masahiko; Sato, Mariko; Hirose, Katsumi; Akimoto, Hiroyoshi; Kawaguchi, Hideo; Hatayama, Yoshiomi; Ono, Shuichi; Takai, Yoshihiro

    2015-01-01

    Radiation-induced rib fracture after stereotactic body radiotherapy (SBRT) for lung cancer has been recently reported. However, incidence of radiation-induced rib fracture after SBRT using moderate fraction sizes with a long-term follow-up time are not clarified. We examined incidence and risk factors of radiation-induced rib fracture after SBRT using moderate fraction sizes for the patients with peripherally located lung tumor. During 2003–2008, 41 patients with 42 lung tumors were treated with SBRT to 54–56 Gy in 9–7 fractions. The endpoint in the study was radiation-induced rib fracture detected by CT scan after the treatment. All ribs where the irradiated doses were more than 80% of prescribed dose were selected and contoured to build the dose-volume histograms (DVHs). Comparisons of the several factors obtained from the DVHs and the probabilities of rib fracture calculated by Kaplan-Meier method were performed in the study. Median follow-up time was 68 months. Among 75 contoured ribs, 23 rib fractures were observed in 34% of the patients during 16–48 months after SBRT, however, no patients complained of chest wall pain. The 4-year probabilities of rib fracture for maximum dose of ribs (Dmax) more than and less than 54 Gy were 47.7% and 12.9% (p = 0.0184), and for fraction size of 6, 7 and 8 Gy were 19.5%, 31.2% and 55.7% (p = 0.0458), respectively. Other factors, such as D2cc, mean dose of ribs, V10–55, age, sex, and planning target volume were not significantly different. The doses and fractionations used in this study resulted in no clinically significant rib fractures for this population, but that higher Dmax and dose per fraction treatments resulted in an increase in asymptomatic grade 1 rib fractures

  13. Pocket total dose meter

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; Endres, G.W.R.

    1984-10-01

    Laboratory measurements have demonstrated that it is possible to simultaneously measure absorbed dose and dose equivalent using a single tissue equivalent proportional counter. Small, pocket sized instruments are being developed to determine dose equivalent as the worker is exposed to mixed field radiation. This paper describes the electronic circuitry and computer algorithms used to determine dose equivalent in these devices

  14. Total dose meter development

    International Nuclear Information System (INIS)

    Brackenbush, L.W.

    1986-09-01

    This report describes an alarming ''pocket'' monitor/dosimeter, based on a tissue-equivalent proportional counter, that measure both neutron and gamma dose and determines dose equivalent for the mixed radiation field. This report details the operation of the device and provides information on: the necessity for a device to measure dose equivalent in mixed radiation fields; the mathematical theory required to determine dose equivalent from tissue equivalent proportional; the detailed electronic circuits required; the algorithms required in the microprocessor used to calculate dose equivalent; the features of the instrument; program accomplishments and future plans

  15. Ionizing radiation and autoimmunity: Induction of autoimmune disease in mice by high dose fractionated total lymphoid irradiation and its prevention by inoculating normal T cells

    International Nuclear Information System (INIS)

    Sakaguchi, N.; Sakaguchi, S.; Miyai, K.

    1992-01-01

    Ionizing radiation can functionally alter the immune system and break self-tolerance. High dose (42.5 Gy), fractionated (2.5 Gy 17 times) total lymphoid irradiation (TLI) on mice caused various organ-specific autoimmune diseases, such as gastritis, thyroiditis, and orchitis, depending on the radiation dosages, the extent of lymphoid irradiation, and the genetic background of the mouse strains. Radiation-induced tissue damage is not the primary cause of the autoimmune disease because irradiation of the target organs alone failed to elicit the autoimmunity and shielding of the organs from irradiation was unable to prevent it. In contrast, irradiation of both the thymus and the peripheral lymphoid organs/tissues was required for efficient induction of autoimmune disease by TLI. TLI eliminated the majority of mature thymocytes and the peripheral T cells for 1 mo, and inoculation of spleen cell, thymocyte, or bone marrow cell suspensions (prepared from syngeneic nonirradiated mice) within 2 wk after TLI effectively prevented the autoimmune development. Depletion of T cells from the inocula abrogated the preventive activity. CD4 + T cells mediated the autoimmune prevention but CD8 + T cells did not. CD4 + T cells also appeared to mediate the TLI-induced autoimmune disease because CD4 + T cells from disease-bearing TLI mice adoptively transferred the autoimmune disease to syngeneic naive mice. Taken together, these results indicate that high dose, fractionated ionizing radiation on the lymphoid organs/tissues can cause autoimmune disease by affecting the T cell immune system, rather than the target self-Ags, presumably by altering T cell-dependent control of self-reactive T cells. 62 refs., 9 figs., 2 tabs

  16. Fractionated or single-dose total body irradiation in 171 acute myeloblastic leukemias in first complete remission: is there a best choice?

    International Nuclear Information System (INIS)

    Resbeut, Michel; Cowen, Didier; Blaise, Didier; Gluckman, Eliane; Cosset, Jean-Marc; Rio, Bernard; Pene, Francoise; Milpied, Nicolas; Cuillere, Jean-Claude; Reiffers, Josy; Richaud, Pierre

    1995-01-01

    Purpose: To evaluate the importance of fractionating total body irradiation (TBI) in patients receiving an allogenic bone marrow transplant (BMT) for an acute myeloblastic leukemia (AML) in first complete remission (CR1). Methods and Materials: Between 1983 and 1990, 171 consecutive patients received either single dose TBI (STBI) (n = 65) or fractionated TBI (FTBI) (n = 106) after being conditioned with cyclophosphamide and before receiving a non-T-depleted Human Leucocyte Antigen (HLA)-identical marrow. Both groups were comparable except for date of BMT and diagnosis-to-BMT interval (D-BMT). Results: After 63 months median follow-up, transplant-related mortality (TRM), probability of relapse, and 5-year disease-free survival (DFS) were 0.38 and 0.27 (p = 0.04), 0.29 and 0.26 (p = 0.22), 0.43 and 0.56 (p = 0.06), respectively, for STBI and FTBI. The supposed influence of the schedule of TBI disappeared in the multivariate analysis: TRM was enhanced by severe acute graft vs. host disease (p = 0.0002), early years of transplant (before January 1, 1987) (p = 0.0003), and longer D-BMT intervals (p = 0.038). Relapse was linked to early years of transplant (p < 0.00001), and the absence of chronic GVHD (p = 0.007). Longer DFSs were observed for later years of transplant (after January 1, 1987 and later) (p = 0.001), milder acute GVHD (p = 0.005), and shorter D-BMT intervals (p = 0.045). Important improvements of the results were made during the 7-year observation period: TRM, probability of relapse, and DFS were, respectively, 0.36, 0.28, and 0.46 for patients transplanted before January 1, 1987 vs. 0.21, 0.15, and 0.67 after that date. Conclusion: Our data strongly suggest that allogenic BMT is the best postremission treatment for AML in CR1, and the results are better when BMT shortly follows the achievement of remission. The schedule of TBI was of little importance compared with the improvements made in the management of patients undergoing BMT during the 1980s, and

  17. The dependence of radiation response on the dose per fraction

    International Nuclear Information System (INIS)

    Joiner, M.C.

    1989-01-01

    The linear-quadratic (LQ) model explains the dependence of total dose in a fractionated course on the dose per fraction, in a very wide range of tumour and normal tissue studies, providing the dose per fraction remains above 2 Gy. In the range 2-1 Gy per fraction, some experimental studies show less increase in total dose than predicted by LQ; a probable explanation is incomplete repair between fractions given 2 seen between 1 and 0.1 Gy per fraction. This cannot be explained by incomplete repair; a modified LQ model where α decreases sharply with increasing dose per fraction in the range 0-1 Gy fits these data. The basic LQ model describes data from neutron fractionation studies, so the relationship between relative biological effectiveness (RBE) and X-ray dose per fraction can be expressed in terms of LQ parameters and fitted directly to RBE data. Results from different experiments, different assays and both top-up and full-course fractionation techniques, can all be included in one analysis. (author)

  18. Implication of fractionated dose exposures in therapeutic gain

    International Nuclear Information System (INIS)

    Kim, Hye-Jin; Lee, Min-Ho; Kim, Eun-Hee

    2016-01-01

    Radiation therapy pursues killing tumor cells while sparing normal cells from the radiation exposure. Stereotactic radiosurgery (SRS) is a cancer treatment modality that delivers a high dose in a single operation. This high-dose single operation shortens the treatment course, but can increase the risk of normal cell damage. Normal cell damage can be reduced by employing multi-directional exposures for an increasing number of isocenters. In this study, we investigated whether therapeutic benefits would be expected by employing new dose fractionation patterns at a high-dose single operation. The conventional single-dose operation in brain tumor radiosurgery is performed by delivering fractionated uniform doses. According to Figs. 2 and 3, the conventional radiosurgery might have obtained some therapeutic benefit by employing the fractionated uniform-dose exposures instead of a single-dose exposure. We suggest that further therapeutic gain be expected by employing the fractionated radiation exposures in an increasing dose pattern. Until ensuring our suggestion, the significance in gain of cell surviving should be verified for all three dose patterns with both normal and tumor cells. The investigation whether normal and tumor cells show the same responses to the fractionated dose exposures at lower and higher than 15 Gy of total dose is also reserved for future work

  19. Radiotherapy Dose Fractionation under Parameter Uncertainty

    International Nuclear Information System (INIS)

    Davison, Matt; Kim, Daero; Keller, Harald

    2011-01-01

    In radiotherapy, radiation is directed to damage a tumor while avoiding surrounding healthy tissue. Tradeoffs ensue because dose cannot be exactly shaped to the tumor. It is particularly important to ensure that sensitive biological structures near the tumor are not damaged more than a certain amount. Biological tissue is known to have a nonlinear response to incident radiation. The linear quadratic dose response model, which requires the specification of two clinically and experimentally observed response coefficients, is commonly used to model this effect. This model yields an optimization problem giving two different types of optimal dose sequences (fractionation schedules). Which fractionation schedule is preferred depends on the response coefficients. These coefficients are uncertainly known and may differ from patient to patient. Because of this not only the expected outcomes but also the uncertainty around these outcomes are important, and it might not be prudent to select the strategy with the best expected outcome.

  20. Radiobiological aspects of continuous low dose-rate irradiation and fractionated high dose-rate irradiation

    International Nuclear Information System (INIS)

    Turesson, I.

    1990-01-01

    The biological effects of continuous low dose-rate irradiation and fractionated high dose-rate irradiation in interstitial and intracavitary radiotherapy and total body irradiation are discussed in terms of dose-rate fractionation sensitivity for various tissues. A scaling between dose-rate and fraction size was established for acute and late normal-tissue effects which can serve as a guideline for local treatment in the range of dose rates between 0.02 and 0.005 Gy/min and fraction sizes between 8.5 and 2.5 Gy. This is valid provided cell-cycle progression and proliferation can be ignored. Assuming that the acute and late tissue responses are characterized by α/β values of about 10 and 3 Gy and a mono-exponential repair half-time of about 3 h, the same total doses given with either of the two methods are approximately equivalent. The equivalence for acute and late non-hemopoietic normal tissue damage is 0.02 Gy/min and 8.5 Gy per fraction; 0.01 Gy/min and 5.5 Gy per fraction; and 0.005 Gy/min and 2.5Gy per fraction. A very low dose rate, below 0.005 Gy/min, is thus necessary to simulate high dose-rate radiotherapy with fraction sizes of about 2Gy. The scaling factor is, however, dependent on the repair half-time of the tissue. A review of published data on dose-rate effects for normal tissue response showed a significantly stronger dose-rate dependence for late than for acute effects below 0.02 Gy/min. There was no significant difference in dose-rate dependence between various acute non-hemopoietic effects or between various late effects. The consistent dose-rate dependence, which justifies the use of a general scaling factor between fraction size and dose rate, contrasts with the wide range of values for repair half-time calculated for various normal-tissue effects. This indicates that the model currently used for repair kinetics is not satisfactory. There are also few experimental data in the clinical dose-rate range, below 0.02 Gy/min. It is therefore

  1. Acoustic neuromas: single dose vs fractionated therapy

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    Fuss, M; Debus, J; Lohr, F; Engenhart-Cabillic, R; Wannenmacher, M

    1997-07-01

    Purpose: Radiosurgical treatment (RS) of acoustic neuromas is a well established treatment. However, few data are available concerning conformal fractionated radiotherapy (FT) of this tumor entity. We evaluated treatment outcome and toxicity for both treatment modalities in 41 patients treated at our institution between 1984 and 1997. Material and Methods: All treatments were performed using a specially adapted linear accelerator and circular collimators for convergent beam RS or multi-leaf collimators (leaf thickness 1 or 3mm) for multi-field RS or fractionated treatment. 22 patients (7 male, 15 female, median age 60 years, range 20-83 years) were treated radiosurgically with single doses between 7 and 28 Gray (median 15 Gy) prescribed to the 80% isodose line. Tumor volumes ranged from 0.7 to 10.5 ccm with a median volume of 3.4 ccm. The median number of isocenters was 2 (1-4 isocenters). One patient was treated by a multi-field technique (14 isocentric irregularly shaped noncoplanar fields). 19 patients (5 male, 14 female, median age 55 years, range 20-81 years) were treated with stereotactic conformal radiotherapy. Median dose was 60 Gray with a median daily fraction size of 2 Gy and a median of 3 (1-4) irregularly shaped isocentric fields. Tumor volumes ranged from 0.7 to 32.4 ccm (median 15 ccm). Median follow-up was 30 months (7-149 months) for radiosurgical and 30 months (2-88 months) for fractionated treatment. Seven patients who underwent fractionated treatment had previously undergone neurosurgical resection on the contralateral side. One had undergone radiosurgery on the opposite side before. Results: All tumors were locally controlled. A volume reduction of more than 20% was seen in 16% after RS and 18% following FT. Typical posttherapeutic central reduction of contrast media enhancement was found in 73% following RS after a median of 8 (3-12) months and in 63% following FT after a median of 6 (1-12) months. Temporary brainstem edema was diagnosed in 4

  2. Therapeutic use of fractionated total body and subtotal body irradiation

    International Nuclear Information System (INIS)

    Loeffler, R.K.

    1981-01-01

    Ninety-one patients were treated using fractionated subtotal body (STBI) or total body irradiation (TBI). These patients had generalized lymphomas, Hodgkin's disease, leukemias, myelomas, seminomas, or oat-cell carcinomas. Subtotal body irradiation is delivered to the entire body, except for the skull and extremities. It was expected that a significantly higher radiation dose could be administered with STBI than with TBI. A five- to ten-fold increase in tolerance for STBI was demonstrated. Many of these patients have had long-term emissions. There is little or no treatment-induced symptomatology, and no sanctuary sites

  3. 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.

  4. 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.

  5. Acoustic neuromas: single dose vs fractionated therapy

    International Nuclear Information System (INIS)

    Fuss, M.; Debus, J.; Lohr, F.; Engenhart-Cabillic, R.; Wannenmacher, M.

    1997-01-01

    Purpose: Radiosurgical treatment (RS) of acoustic neuromas is a well established treatment. However, few data are available concerning conformal fractionated radiotherapy (FT) of this tumor entity. We evaluated treatment outcome and toxicity for both treatment modalities in 41 patients treated at our institution between 1984 and 1997. Material and Methods: All treatments were performed using a specially adapted linear accelerator and circular collimators for convergent beam RS or multi-leaf collimators (leaf thickness 1 or 3mm) for multi-field RS or fractionated treatment. 22 patients (7 male, 15 female, median age 60 years, range 20-83 years) were treated radiosurgically with single doses between 7 and 28 Gray (median 15 Gy) prescribed to the 80% isodose line. Tumor volumes ranged from 0.7 to 10.5 ccm with a median volume of 3.4 ccm. The median number of isocenters was 2 (1-4 isocenters). One patient was treated by a multi-field technique (14 isocentric irregularly shaped noncoplanar fields). 19 patients (5 male, 14 female, median age 55 years, range 20-81 years) were treated with stereotactic conformal radiotherapy. Median dose was 60 Gray with a median daily fraction size of 2 Gy and a median of 3 (1-4) irregularly shaped isocentric fields. Tumor volumes ranged from 0.7 to 32.4 ccm (median 15 ccm). Median follow-up was 30 months (7-149 months) for radiosurgical and 30 months (2-88 months) for fractionated treatment. Seven patients who underwent fractionated treatment had previously undergone neurosurgical resection on the contralateral side. One had undergone radiosurgery on the opposite side before. Results: All tumors were locally controlled. A volume reduction of more than 20% was seen in 16% after RS and 18% following FT. Typical posttherapeutic central reduction of contrast media enhancement was found in 73% following RS after a median of 8 (3-12) months and in 63% following FT after a median of 6 (1-12) months. Temporary brainstem edema was diagnosed in 4

  6. Effects of dose fractionation on the response of alanine dosimetry

    International Nuclear Information System (INIS)

    Lundahl, Brad; Logar, John; Desrosiers, Marc; Puhl, James

    2014-01-01

    Alanine dosimetry is well established as a transfer standard and is becoming more prevalently used in routine dosimetry systems for radiation processing. Many routine measurement applications in radiation processing involve absorbed dose measurements resulting from fractioned exposures to ionizing radiation. Fractioning of absorbed dose is identified as an influence quantity (ISO/ASTM, 2013). This paper reports on study results of absorbed dose fractioning characteristics of alanine for gamma and high energy electron beam radiation sources. The results of this study indicate a radiation response difference due to absorbed dose fractioning in response can be observed after four fractionations for high-energy electron beams and no difference up to seven fractions for gamma rays using an ANOVA evaluation method. - Highlights: • Fractioning effects signaled in electron beam using an ANOVA at 6 equal increments. • Fractioning effects not signaled in gamma using an ANOVA up to 7 equal increments. • Insensitivity of alanine to dose fractioning indicates nominal impact on calibration

  7. 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

  8. Method to account for dose fractionation in analysis of IMRT plans: Modified equivalent uniform dose

    International Nuclear Information System (INIS)

    Park, Clinton S.; Kim, Yongbok; Lee, Nancy; Bucci, Kara M.; Quivey, Jeanne M.; Verhey, Lynn J.; Xia Ping

    2005-01-01

    Purpose: To propose a modified equivalent uniform dose (mEUD) to account for dose fractionation using the biologically effective dose without losing the advantages of the generalized equivalent uniform dose (gEUD) and to report the calculated mEUD and gEUD in clinically used intensity-modulated radiotherapy (IMRT) plans. Methods and Materials: The proposed mEUD replaces the dose to each voxel in the gEUD formulation by a biologically effective dose with a normalization factor. We propose to use the term mEUD D o /n o that includes the total dose (D o ) and number of fractions (n o ) and to use the term mEUD o that includes the same total dose but a standard fraction size of 2 Gy. A total of 41 IMRT plans for patients with nasopharyngeal cancer treated at our institution between October 1997 and March 2002 were selected for the study. The gEUD and mEUD were calculated for the planning gross tumor volume (pGTV), planning clinical tumor volume (pCTV), parotid glands, and spinal cord. The prescription dose for these patients was 70 Gy to >95% of the pGTV and 59.4 Gy to >95% of the pCTV in 33 fractions. Results: The calculated average gEUD was 72.2 ± 2.4 Gy for the pGTV, 54.2 ± 7.1 Gy for the pCTV, 26.7 ± 4.2 Gy for the parotid glands, and 34.1 ± 6.8 Gy for the spinal cord. The calculated average mEUD D o /n o using 33 fractions was 71.7 ± 3.5 Gy for mEUD 70/33 of the pGTV, 49.9 ± 7.9 Gy for mEUD 59.5/33 of the pCTV, 27.6 ± 4.8 Gy for mEUD 26/33 of the parotid glands, and 32.7 ± 7.8 Gy for mEUD 45/33 of the spinal cord. Conclusion: The proposed mEUD, combining the gEUD with the biologically effective dose, preserves all advantages of the gEUD while reflecting the fractionation effects and linear and quadratic survival characteristics

  9. Small dose multi-fractionation therapy, its radiobiological aspects and clinics

    International Nuclear Information System (INIS)

    Iwai, Hiroshi; Katagiri, Shiro; Furuhata, Akihiko; Fukusi, Itsuhisa

    1979-01-01

    Recent radiobiological data reveal that cell killings by small dose fractionation are almost due to nonrepairable damage with low oxygen enhancement ratio. Then, Small dose multi-fractionation method suggests a higher therapeutic-ratio than that in conventional high dose fractionated irradiation. Using these data of radiobiology, intermittent irradiations three times a day, four hours interval, with 60 - 80 rads for multi-fractionation, with high total doses of 7,200 - 7,500 rads/6.5 - 7 weeks mainly on bladder, laryngeal and esophageal tumour are applied. The results obtained are slightly improved. (author)

  10. Phase-II trial of fractionated total body radiation in bone marrow transplantation for acute leukemia

    International Nuclear Information System (INIS)

    Gale, R.P.; Opelz, G.; Feig, S.

    1979-01-01

    The addition of low doses of fractionated total body irradiation and a radiosensitizing agent to more conventional doses of total body irradiation was well tolerated but did not improve the antileukemic effect. The DAFT regimen was not associated with a higher incidence of GVHD or interstitial pneumonitis. This observation has led us to consider escalation of the dose of FTBI in our next clinical trial

  11. Decreased uptake after fractionated ablative doses of iodine-131

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hurng-Sheng [Show Chwan Memorial Hospital, Department of Surgery, Changhua, Taiwan (Taiwan); Hseu, Huey-Herng [Taichung Veterans General Hospital, Department of Medical Education and Research, Taichung (Taiwan); Lin, Wan-Yu; Wang, Shyh-Jen [Taichung Veterans General Hospital, Department of Nuclear Medicine, Taichung, Taiwan (Taiwan); Liu, Yao-Chi [Department of Surgery, General Surgery, National Defense Medical Center, Taipe (Taiwan)

    2005-02-01

    In an attempt to obviate the necessity for hospitalisation, the ablative dose of {sup 131}I in the treatment of thyroid cancer is divided into two or three fractions at weekly intervals in some hospitals with no special bed for {sup 131}I treatment. Thyroid stunning has been observed in patients receiving a {sup 131}I dose between 74 and 370 MBq (2-10 mCi). However, the influence of {sup 131}I uptake after administration of a higher dose, such as 1,110-1,850 MBq of {sup 131}I, has never been reported. In this study, we evaluated the degree of reduction in {sup 131}I uptake after patients received 1,480 MBq of {sup 131}I and evaluated the clinical value of fractionated ablative doses of {sup 131}I. Thirty-five patients with functional thyroid cancer received a total of 4,440 MBq (120 mCi) of {sup 131}I which was divided into three fractions administered at weekly intervals. In all patients two {sup 131}I whole-body scans were performed. The first scan was performed directly prior to the second dose of {sup 131}I (7 days after the first administration of {sup 131}I), and the second scan was performed 7 days after the second administration of {sup 131}I and directly prior to the third administration. Regions of interest including the neck and lungs were drawn to calculate the uptake of {sup 131}I in the thyroid remnant and possible cervical lymph node and lung metastases. The mean uptake of {sup 131}I was 2.73% 7 days after the first administration, and decreased significantly to 0.26% 7 days after the second administration. The mean decrease was as high as 80.7%. The decrease in {sup 131}I uptake was significant in all patients except the two with lung metastases. In the two patients with lung metastases, no definite evidence of decreased uptake was noted; the uptake of {sup 131}I in the lung metastases even increased on the second {sup 131}I image in one of these patients. After administration of 1,480 MBq of {sup 131}I, the decreased uptake was significant in all

  12. On the effect of small radiation doses: Desoxyribonucleic acid (DNA) synthesis and DNA repair of thymus, spleen, and bone marrow cells in the rat after fractionated total body X-ray irradiation. Zur Wirkung kleiner Strahlendosen: Desoxyribonukleinsaeure-(DNA-)Synthese und DNA-Reparatur von Thymus-, Milz- und Knochenmarkszellen der Ratte nach fraktionierter Ganzkoerperroentgenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Tempel, K.; Ehling, G. (Muenchen Univ. (Germany, F.R.). Inst. fuer Pharmakologie, Toxikologie und Pharmazie)

    1989-09-01

    After three to seven days following to fractionated total body X-ray irradiation (TBI) (four expositions with doses of 0.3 to 5.0 cGy per fraction at intervals of 24 hours), a maximum 50 percent stimulation of the semiconservative DNA synthesis (SDS) of spleen cells was measured in vitro. This was not dependent of the fact if an acute high-dose (400 and/or 800 cGy) unique irradiation was applied after the fractionated TBI at the moment of stimulation. A significant increase of {sup 3}H-thymidine incorporation into the DNA of bone marrow and thymus cells was only found when doses of 1.25 cGy per fraction had been used. After fractionated TBI with doses of {ge}5 cGy per fraction, an increase of DNA synthesis resistant to hydroxyurea ('unprogrammed' DNA synthesis, UDS) was demonstrated in spleen cells. The UV-simulated UDS decreased proportionately. The sedimentation of thymus, spleen, and bone marrow nucleoids in a neutral saccharose gradient gave no evidence of an increased DNA repair capacity after fractionated TBI. Whereas the SDS stimulation by fractionated TBI with small doses can be explained by a modified proliferation behavior of exposed cells, the UDS behavior of spleen cells after considerably higher radiation doses suggests regenerative processes correlated with an increased number of cells resistant to hydroxyurea and cells presenting an UV repair deficiency. These findings can be considered to be a further proof of the assumed immune-stimulating effect of small radiation doses. (orig.).

  13. Pulsed dose rate and fractionated high dose rate brachytherapy: choice of brachytherapy schedules to replace low dose rate treatments

    International Nuclear Information System (INIS)

    Visser, Andries G.; Aardweg, Gerard J.M.J. van den; Levendag, Peter C.

    1996-01-01

    Purpose: Pulsed dose rate (PDR) brachytherapy is a new type of afterloading brachytherapy (BT) in which a continuous low dose rate (LDR) treatment is simulated by a series of 'pulses,' i.e., fractions of short duration (less than 0.5 h) with intervals between fractions of 1 to a few hours. At the Dr. Daniel den Hoed Cancer Center, the term 'PDR brachytherapy' is used for treatment schedules with a large number of fractions (at least four per day), while the term 'fractionated high dose rate (HDR) brachytherapy' is used for treatment schedules with just one or two brachytherapy fractions per day. Both treatments can be applied as alternatives for LDR BT. This article deals with the choice between PDR and fractionated HDR schedules and proposes possible fractionation schedules. Methods and Materials: To calculate HDR and PDR fractionation schedules with the intention of being equivalent to LDR BT, the linear-quadratic (LQ) model has been used in an incomplete repair formulation as given by Brenner and Hall, and by Thames. In contrast to earlier applications of this model, both the total physical dose and the overall time were not kept identical for LDR and HDR/PDR schedules. A range of possible PDR treatment schedules is presented, both for booster applications (in combination with external radiotherapy (ERT) and for BT applications as a single treatment. Because the knowledge of both α/β values and the half time for repair of sublethal damage (T (1(2)) ), which are required for these calculations, is quite limited, calculations regarding the equivalence of LDR and PDR treatments have been performed for a wide range of values of α/β and T (1(2)) . The results are presented graphically as PDR/LDR dose ratios and as ratios of the PDR/LDR tumor control probabilities. Results: If the condition that total physical dose and overall time of a PDR treatment must be exactly identical to the values for the corresponding LDR treatment regimen is not applied, there appears

  14. IMRT dose fractionation for head and neck cancer: Variation in current approaches will make standardisation difficult

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Kean F. (Academic Dept. of Radiation Oncology, Univ. of Manchester, Manchester (United Kingdom)); Fowler, Jack F. (Dept. of Human Oncology and Medical Physics, Univ. of Wisconsin, Wisconsin (United States)); Sykes, Andrew J.; Yap, Beng K.; Lee, Lip W.; Slevin, Nick J. (Dept. of Clinical Oncology, Christie Hospital NHS Foundation Trust, Manchester (United Kingdom))

    2009-04-15

    Introduction. Altered fractionation has demonstrated clinical benefits compared to the conventional 2 Gy/day standard of 70 Gy. When using synchronous chemotherapy, there is uncertainty about optimum fractionation. IMRT with its potential for Simultaneous Integrated Boost (SIB) adds further to this uncertainty. This survey will examine international practice of IMRT fractionation and suggest possible reasons for diversity in approach. Material and methods. Fourteen international cancer centres were surveyed for IMRT dose/fractionation practised in each centre. Results. Twelve different types of dose fractionation were reported. Conventional 70-72 Gy (daily 2 Gy/fraction) was used in 3/14 centres with concurrent chemotherapy while 11/14 centres used altered fractionation. Two centres used >1 schedule. Reported schedules and number of centres included 6 fractions/week DAHANCA regime (3), modest hypofractionation (=2.2 Gy/fraction) (3), dose-escalated hypofractionation (=2.3 Gy/fraction) (4), hyperfractionation (1), continuous acceleration (1) and concomitant boost (1). Reasons for dose fractionation variability include (i) dose escalation; (ii) total irradiated volume; (iii) number of target volumes; (iv) synchronous systemic treatment; (v) shorter overall treatment time; (vi) resources availability; (vii) longer time on treatment couch; (viii) variable GTV margins; (ix) confidence in treatment setup; (x) late tissue toxicity and (xi) use of lower neck anterior fields. Conclusions. This variability in IMRT fractionation makes any meaningful comparison of treatment results difficult. Some standardization is needed particularly for design of multi-centre randomized clinical trials.

  15. Prooxidate - antioxidate homeostasis in guinea pigs after fractional low-dose irradiation

    International Nuclear Information System (INIS)

    Baraboj, V.A.; Olyijnik, S.A.; Khmelevs'kij, Yi.V.

    1993-01-01

    We studied the influence of fractional total irradiation in the total dose of 1 Gy on the amount of lipids peroxide oxidation (LPO) products and ascorbic acid in the spleen, intestine and brain of guinea-pigs. The obtained date suggest that it is advisable to use ascorbic acid to correct postirradiation changes in the organism exposed to small doses of ionizing radiation

  16. p-MOSFET total dose dosimeter

    Science.gov (United States)

    Buehler, Martin G. (Inventor); Blaes, Brent R. (Inventor)

    1994-01-01

    A p-MOSFET total dose dosimeter where the gate voltage is proportional to the incident radiation dose. It is configured in an n-WELL of a p-BODY substrate. It is operated in the saturation region which is ensured by connecting the gate to the drain. The n-well is connected to zero bias. Current flow from source to drain, rather than from peripheral leakage, is ensured by configuring the device as an edgeless MOSFET where the source completely surrounds the drain. The drain junction is the only junction not connected to zero bias. The MOSFET is connected as part of the feedback loop of an operational amplifier. The operational amplifier holds the drain current fixed at a level which minimizes temperature dependence and also fixes the drain voltage. The sensitivity to radiation is made maximum by operating the MOSFET in the OFF state during radiation soak.

  17. Changes in tumor cell response due to prolonged dose delivery times in fractionated radiation therapy

    International Nuclear Information System (INIS)

    Paganetti, Harald

    2005-01-01

    Purpose: Dynamic radiation therapy, such as intensity-modulated radiation therapy, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The cellular damage after a full treatment may depend on the dose rate, because sublethal radiation damage can be repaired more efficiently during prolonged dose delivery. The goal of this study was to investigate the significance of this effect in fractionated radiation therapy. Methods and Materials: The lethal/potentially lethal model was used to calculate lesion induction rates for repairable and nonrepairable lesions. Dose rate effects were analyzed for 9 different cell lines (8 human tumor xenografts and a C3H10T1/2 cell line). The effects of single-fraction as well as fractionated irradiation for different dose rates were studied. Results: Significant differences can be seen for dose rates lower than about 0.1 Gy/min for all cell lines considered. For 60 Gy delivered in 30 fractions, the equivalent dose is reduced by between 1.3% and 12% comparing 2 Gy delivery over 30 min per fraction with 2 Gy delivery over 1 min per fraction. The effect is higher for higher doses per fraction. Furthermore, the results show that dose rate effects do not show a simple correlation with the α/β ratio for ratios between 3 Gy and 31 Gy. Conclusions: If the total dose delivery time for a treatment fraction in radiation therapy increases to about 20 min, a correction for dose rate effects may have to be considered in treatment planning. Adjustments in effective dose may be necessary when comparing intensity-modulated radiation therapy with conventional treatment plans

  18. Benefits of online in vivo dosimetry for single-fraction total body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Eaton, David J., E-mail: davideaton@nhs.net [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom); Warry, Alison J. [Department of Radiotherapy Physics, University College London Hospital, London (United Kingdom); Trimble, Rachel E.; Vilarino-Varela, Maria J.; Collis, Christopher H. [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom)

    2014-01-01

    Use of a patient test dose before single-fraction total body irradiation (TBI) allows review of in vivo dosimetry and modification of the main treatment setup. However, use of computed tomography (CT) planning and online in vivo dosimetry may reduce the need for this additional step. Patients were treated using a supine CT-planned extended source-to-surface distance (SSD) technique with lead compensators and bolus. In vivo dosimetry was performed using thermoluminescent dosimeters (TLDs) and diodes at 10 representative anatomical locations, for both a 0.1-Gy test dose and the treatment dose. In total, 28 patients were treated between April 2007 and July 2013, with changes made in 10 cases (36%) following test dose results. Overall, 98.1% of measured in vivo treatment doses were within 10% of the prescribed dose, compared with 97.0% of test dose readings. Changes made following the test dose could have been applied during the single-fraction treatment itself, assuming that the dose was delivered in subportions and online in vivo dosimetry was available for all clinically important anatomical sites. This alleviates the need for a test dose, saving considerable time and resources.

  19. Benefits of online in vivo dosimetry for single-fraction total body irradiation

    International Nuclear Information System (INIS)

    Eaton, David J.; Warry, Alison J.; Trimble, Rachel E.; Vilarino-Varela, Maria J.; Collis, Christopher H.

    2014-01-01

    Use of a patient test dose before single-fraction total body irradiation (TBI) allows review of in vivo dosimetry and modification of the main treatment setup. However, use of computed tomography (CT) planning and online in vivo dosimetry may reduce the need for this additional step. Patients were treated using a supine CT-planned extended source-to-surface distance (SSD) technique with lead compensators and bolus. In vivo dosimetry was performed using thermoluminescent dosimeters (TLDs) and diodes at 10 representative anatomical locations, for both a 0.1-Gy test dose and the treatment dose. In total, 28 patients were treated between April 2007 and July 2013, with changes made in 10 cases (36%) following test dose results. Overall, 98.1% of measured in vivo treatment doses were within 10% of the prescribed dose, compared with 97.0% of test dose readings. Changes made following the test dose could have been applied during the single-fraction treatment itself, assuming that the dose was delivered in subportions and online in vivo dosimetry was available for all clinically important anatomical sites. This alleviates the need for a test dose, saving considerable time and resources

  20. The influence of dose per fraction on repair kinetics

    International Nuclear Information System (INIS)

    Rojas, A.; Joiner, M.C.

    1989-01-01

    The use of multiple fractions per day (MFD) in radiotherapy requires information about the rate of repair of radiation injury. It is important to know the minimum interval between fractions necessary for maximum sparing of normal tissue damage, whether rate of repair is dependent on the size of dose per fraction and if it is different in early and late responding tissues and in tumours. To address these questions, the rate of repair between radiation dose fractions was measured in mouse skin (acute damage), mouse kidney (late damage) and a mouse tumour (carcinoma NT). Skin and kidney measurements were made using multiple split doses of X-rays, followed by a neutron top-up. For skin, faster recovery was obtained with 4.4 Gy fractions (t1/2 = 3.46 ± 0.88 h). In contrast kidney showed slower recovery at a low dose per fraction of 2 Gy (t1/2 = 1.69 ± 0.39 h) than at a higher dose of 7 Gy per fraction (t1/2 = 0.92 ± 0.1h). These data show that repair rate is dependent on the size of dose per fraction, but not in a simple way. T1/2 values now available for many different tissues generally lie in the range of 1-2h, and are not correlated with proliferation status or early versus late response to treatment. At the doses used currently in clinical MFD treatments, these data indicate that damage in almost all normal tissues would increase if interfraction intervals less than 6 h were used. The t1/2 for CaNT (0.31 ± 0.15 h) is less than for any normal tissue. This underlines that the excess morbidity resulting from interfraction intervals < 6 h will not be paralleled by an increased effect in tumours. (author). 25 refs.; 7 figs

  1. Total Phenol amd Flavonoid contents of Crude Extract and Fractions ...

    African Journals Online (AJOL)

    Phenolic compounds are numerous in plants and are essential part of human diet. Picralima nitida has been extensively used in African folk medicine especially in West Africa. The present study evaluated the total phenolic and flavonoid contents of the extract and fractions of Picralima nitida. The methanol extracts of P.

  2. Late effects of various dose-fractionation regimens

    International Nuclear Information System (INIS)

    Turesson, I.; Notter, G.

    1983-01-01

    These clinical investigations of various dose-fractionation regimens on human skin show that: The late reactions cannot be predicted from the early reactions; The dose-response curves for late reactions are much steeper than for early reactions; Equivalent doses for various fractionation schedules concerning late effects can be calculated by means of a corrected CRE (NSD) formula; the correction must be considered preliminary because further follow-up is needed. A clinical fractionation study of this type requires: Extremely careful dosimetry; Study of the same anatomical region; Very long follow-up; Studies at different effect levels; Skin reaction is the only end point we have studied systematically for different fractionation regimens. Experience with the CRE formula as a model for calculating isoeffect doses for different fractionation schedules in routine clinical use can be summarized as follows: The CRE formula has been used prospectively since 1972 in all patients; CRE-equivalent weekly doses to 5 x 2.0 Gy per week has been used. (Although the fractionation schedule is changed, the overall treatment time is still the same); The CRE range was 18 to 21 for curative radiotherapy on carcinomas; No irradiation was applied during pronounced acute reactions. No unexpected complications have been observed under these conditions

  3. Fractionated homogenous total-body irradiation prior to bone marrow transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Duehmke, E; Brix, F; Hebbinghaus, D; Jensen, M; Wendhausen, H; Schmitz, N

    1985-03-01

    At the University of Kiel, myeloid and acute lymphatic leukemia is treated since 1983 by total-body irradiation applied prior to bone marrow transplantation. Dose deviations in the midplane caused by the irregular surface and tissue inhomogeneities of the patient are reduced down to +-3.5% compared to the central ray, with the help of CT-based individual compensators. This method prevents above all an excessive dose to the lungs. The radiobiologic advantages of fractionated irradiation have been employed for all patients treated hitherto (n = 9). At present, a total body dose of 12 Gy in six fractions is applied within three days. There were no undesired acute radiogenic reactions except a mild acute mucositis found in all patients. Chronic side effects, especially in the lungs, were not demonstrated, too. However, the average follow-up time of 149 days has been rather short. One patient died from relapse of leukemia after a total dose of 10 Gy, another patient died because the transplanted bone marrow was rejected, and a third died from catheter sepsis. Six out of nine patients are in complete remission with a maximum index of Karnofsky. The limited experiences gained hitherto show that the homogeneous accelerated-fractionated total-body irradiation offers essential advantages compared to non-compensated single dose irradiation with respect to the prevention of undesired radiogenic effects in sound tissues and that its therapeutic efficacy is at least the same.

  4. Dose fractionation theorem in 3-D reconstruction (tomography)

    International Nuclear Information System (INIS)

    Glaeser, R.M.

    1997-01-01

    It is commonly assumed that the large number of projections for single-axis tomography precludes its application to most beam-labile specimens. However, Hegerl and Hoppe have pointed out that the total dose required to achieve statistical significance for each voxel of a computed 3-D reconstruction is the same as that required to obtain a single 2-D image of that isolated voxel, at the same level of statistical significance. Thus a statistically significant 3-D image can be computed from statistically insignificant projections, as along as the total dosage that is distributed among these projections is high enough that it would have resulted in a statistically significant projection, if applied to only one image. We have tested this critical theorem by simulating the tomographic reconstruction of a realistic 3-D model created from an electron micrograph. The simulations verify the basic conclusions of high absorption, signal-dependent noise, varying specimen contrast and missing angular range. Furthermore, the simulations demonstrate that individual projections in the series of fractionated-dose images can be aligned by cross-correlation because they contain significant information derived from the summation of features from different depths in the structure. This latter information is generally not useful for structural interpretation prior to 3-D reconstruction, owing to the complexity of most specimens investigated by single-axis tomography. These results, in combination with dose estimates for imaging single voxels and measurements of radiation damage in the electron microscope, demonstrate that it is feasible to use single-axis tomography with soft X-ray microscopy of frozen-hydrated specimens

  5. Dose fractionation theorem in 3-D reconstruction (tomography)

    Energy Technology Data Exchange (ETDEWEB)

    Glaeser, R.M. [Lawrence Berkeley National Lab., CA (United States)

    1997-02-01

    It is commonly assumed that the large number of projections for single-axis tomography precludes its application to most beam-labile specimens. However, Hegerl and Hoppe have pointed out that the total dose required to achieve statistical significance for each voxel of a computed 3-D reconstruction is the same as that required to obtain a single 2-D image of that isolated voxel, at the same level of statistical significance. Thus a statistically significant 3-D image can be computed from statistically insignificant projections, as along as the total dosage that is distributed among these projections is high enough that it would have resulted in a statistically significant projection, if applied to only one image. We have tested this critical theorem by simulating the tomographic reconstruction of a realistic 3-D model created from an electron micrograph. The simulations verify the basic conclusions of high absorption, signal-dependent noise, varying specimen contrast and missing angular range. Furthermore, the simulations demonstrate that individual projections in the series of fractionated-dose images can be aligned by cross-correlation because they contain significant information derived from the summation of features from different depths in the structure. This latter information is generally not useful for structural interpretation prior to 3-D reconstruction, owing to the complexity of most specimens investigated by single-axis tomography. These results, in combination with dose estimates for imaging single voxels and measurements of radiation damage in the electron microscope, demonstrate that it is feasible to use single-axis tomography with soft X-ray microscopy of frozen-hydrated specimens.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  7. A dose-surviving fraction curve for mouse colonic mucosa

    International Nuclear Information System (INIS)

    Tucker, S.L.; Thames, H.D. Jr.; Withers, H.R.; Mason, K.A.

    1983-01-01

    A dose-surviving fraction curve representing the response of the mouse colonic mucosa to single doses of 137 Cs gamma radiation was obtained from the results of a multifraction in vivo colony assay. Construction of the curve required an estimated of the average number of clonogens initially present per colonic crypt. The estimated clonogen count (88) was determined by a statistical method based on the use of doses per fraction common to different fractionation protocols. Parameters for the LQ and TC models of cell survival were obtained by weighted least-squares fits to the data. A comparison of the survival characteristics of cells from the mouse colonic and jejunal crypts suggested that the epithelium of the colon is less radiosensitive than that of the jejunum. (author)

  8. Alternate day treatment and late effects: The concept of an effective dose per fraction

    International Nuclear Information System (INIS)

    Courdi, A.; Hery, M.; Gabillat, J.M.

    1990-01-01

    Although most institutions treat all fields each day, some radiotherapists continue to adopt an alternate day schedule. The resulting daily variations of the dose per fraction in laterally located targets have been analyzed using the linear-quadratic model. Patients with breast carcinoma treated with definitive radiotherapy in 1974-1975 with one field a day were studied. An effective dose per fraction was derived, with a value higher than the average dose per fraction received by the reference point. The greater the fluctuations between the doses per fraction on successive days, the higher the effective dose per fraction. The corresponding cell survival due to alternate treatment as compared to survival with daily treatment depends on the alpha/beta ratio. For a late effect with low alpha/beta ratio, an alternate treatment may lead to almost 10-fold increase in cell kill in these lateral targets such as those responsible for subcutaneous sclerosis as compared to daily treatment of all fields with the same total dose. Taking the average effective dose per fraction in our series, the increase in cell kill was 4-fold. Acute effects would suffer less damage due to alternate treatment because of a high alpha/beta ratio. Treatment on an alternate schedule should be restricted to palliative radiotherapy

  9. Immunosuppression by fractionated total lymphoid irradiation in collagen arthritis

    International Nuclear Information System (INIS)

    McCune, W.J.; Buckley, J.A.; Belli, J.A.; Trentham, D.E.

    1982-01-01

    Treatments with fractionated total lymphoid irradiation (TLI) and cyclophosphamide were evaluated for rats injected with type II collagen. Preadministration of TLI and repeated injections of cyclophosphamide suppressed the severity of arthritis and lowered antibody titers to collagen significantly. TLI initiated at the onset of collagen arthritis decreased humoral and cellular responses to collagen but did not affect the severity of arthritis. These data demonstrate that both TLi and cyclophosphamide are immunosuppressive in an experimentally inducible autoimmune disease

  10. 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.)

  11. Vaccine vial stopper performance for fractional dose delivery of vaccines.

    Science.gov (United States)

    Jarrahian, Courtney; Myers, Daniel; Creelman, Ben; Saxon, Eugene; Zehrung, Darin

    2017-07-03

    Shortages of vaccines such as inactivated poliovirus and yellow fever vaccines have been addressed by administering reduced-or fractional-doses, as recommended by the World Health Organization Strategic Advisory Group of Experts on Immunization, to expand population coverage in countries at risk. We evaluated 3 kinds of vaccine vial stoppers to assess their performance after increased piercing from repeated withdrawal of doses needed when using fractional doses (0.1 mL) from presentations intended for full-dose (0.5 mL) delivery. Self-sealing capacity and fragmentation of the stopper were assessed via modified versions of international standard protocols. All stoppers maintained self-sealing capacity after 100 punctures. The damage to stoppers measured as the fragmentation rate was within the target of ≤ 10% of punctures resulting in a fragment after as many as 50 punctures. We concluded that stopper failure is not likely to be a concern if existing vaccine vials containing up to 10 regular doses are used up to 50 times for fractional dose delivery.

  12. Chromosome aberration yields in human lymphocytes induced by fractionated doses of x-radiation

    International Nuclear Information System (INIS)

    Purrott, R.J.; Reeder, E.

    1976-01-01

    Unstimulated (G 0 ) human peripheral blood lymphocytes were exposed at 37degC to doses of 200 or 500 rad of X-rays delivered in two equal fractions. The dose fractions were separated by intervals of up to 7 h in the 200 rad study and up to 48 h for 500 rad. In both studies the mean levels of dicentrics and total unstable aberrations began to decline when fractions were delivered with intervals of greater than 2 h. With 200 rad the yield had decreased to an additive baseline (i.e. equal to only twice the yield of a single 100-rad fraction) by an interval of 4 h. Following 500 rad the yield declined until 8 h and then remained 20% above the expected additive baseline even when 48 h separated the fractions. Possible explanations for this discrepancy are discussed. In a second experiment PHA stimulated lymphocyte cultures were exposed to 2 doses of 125 rad of X-rays up to 7 h apart in an attempt to demonstrate the late peak in aberration yield originally reported by Lane. Control cultures received unsplit doses of 250 rad at the time of the corresponding second 125-rad fraction. No evidence of a late peak in dicentric yield was observed. The yield remained approximately the same irrespective of the time interval between fractions but these split dose yields were significantly different from the accompanying unsplit controls

  13. The influence of dose fractionation and dose rate on normal tissue responses

    International Nuclear Information System (INIS)

    Barendsen, G.W.

    1982-01-01

    An analysis of responses of a variety of normal tissues in animals to fractionated irradiations has been made with the aim of developing a formalism for the prediction of tolerance doses as a function of the dose per fraction and the overall treatment time. An important feature of the formalism is that it is directly based on radiological insights and therefore provides a logical concept to account for the diversity of tissue responses. (Auth.)

  14. Long-term survival of skin allografts in mice treated with fractionated total lymphoid irradiation

    International Nuclear Information System (INIS)

    Slavin, S.; Strober, S.; Fuks, Z.; Kaplan, H.S.

    1976-01-01

    Treatment of recipient Balb/c mice with fractionated, high-dose total lymphoid irradiation, a procedure commonly used in the therapy of human malignant lymphomas, resulted in fivefold prolongation of the survival of C57BL/Ka skin allografts despite major histocompatibility differences between the strains (H-2/sup d/ and H-2/sup b/, respectively). Infusion of 10 7 (C57BL/Ka x Balb/c)F 1 bone marrow cells after total lymphoid irradiation further prolonged C57BL/Ka skin graft survival to more than 120 days. Total lymphoid irradiation may eventually prove useful in clinical organ transplantation

  15. Response of pig skin to fractionated radiation doses

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  16. Airborne and total gamma absorbed dose rates at Patiala - India

    International Nuclear Information System (INIS)

    Tesfaye, Tilahun; Sahota, H.S.; Singh, K.

    1999-01-01

    The external gamma absorbed dose rate due to gamma rays originating from gamma emitting aerosols in air, is compared with the total external gamma absorbed dose rate at the Physics Department of Punjabi University, Patiala. It has been found out that the contribution, to the total external gamma absorbed dose rate, of radionuclides on particulate matter suspended in air is about 20% of the overall gamma absorbed dose rate. (author)

  17. Advantage of dose fractionation in monoclonal antibody-targeted radioimmunotherapy

    International Nuclear Information System (INIS)

    Schlom, J.; Molinolo, A.; Simpson, J.F.; Siler, K.; Roselli, M.; Hinkle, G.; Houchens, D.P.; Colcher, D.

    1990-01-01

    Monoclonal antibody (MAb) B72.3 IgG was radiolabeled with 131I and administered to female athymic NCr-nu mice bearing the LS-174T human colon adenocarcinoma xenograft to determine if fractionation of MAb dose had any advantage in tumor therapy. In the LS-174T xenograft, only approximately 30%-60% of tumor cells express the B72.3-reactive TAG-72 antigen. The LS-174T xenograft was used to reflect the heterogeneity of the TAG-72 antigen often seen in biopsy specimens from patients. In contrast to a single 600-muCi dose of 131I-B72.3 IgG where 60% of the animals died from toxic effects, two 300-muCi doses of 131I-B72.3 IgG reduced or eliminated tumor growth in 90% of mice, with only 10% of the animals dying from toxic effects. Dose fractionation even permitted escalation of the dose to three doses of 300 muCi of 131I-B72.3 IgG, resulting in even more extensive tumor reduction or elimination and minimal toxic effects. The use of an isotype-matched control MAb revealed a nonspecific component to tumor growth retardation, but the use of the specific B72.3 IgG demonstrated a much greater therapeutic effect. Tumors that had escaped MAb therapy were analyzed for expression of the B72.3-reactive TAG-72 antigen with the use of the immunoperoxidase method; they were shown to have the same antigenic phenotype as the untreated tumors. We verified tumor elimination by killing the test animals after a 7-week observation period and performing histologic examination of tumor sites. We also monitored toxic effects by histologic examination of numerous organs. These studies thus demonstrate the advantage of dose fractionation of a radiolabeled MAb for tumor therapy. We anticipate that the concept of dose fractionation can be practically applied in radioimmunotherapeutic clinical trials with the development and use of recombinant-chimeric MAbs and modified constructs

  18. Secondary radiation dose during high-energy total body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Janiszewska, M.; Raczkowski, M. [Lower Silesian Oncology Center, Medical Physics Department, Wroclaw (Poland); Polaczek-Grelik, K. [University of Silesia, Medical Physics Department, Katowice (Poland); Szafron, B.; Konefal, A.; Zipper, W. [University of Silesia, Department of Nuclear Physics and Its Applications, Katowice (Poland)

    2014-05-15

    The goal of this work was to assess the additional dose from secondary neutrons and γ-rays generated during total body irradiation (TBI) using a medical linac X-ray beam. Nuclear reactions that occur in the accelerator construction during emission of high-energy beams in teleradiotherapy are the source of secondary radiation. Induced activity is dependent on the half-lives of the generated radionuclides, whereas neutron flux accompanies the treatment process only. The TBI procedure using a 18 MV beam (Clinac 2100) was considered. Lateral and anterior-posterior/posterior-anterior fractions were investigated during delivery of 2 Gy of therapeutic dose. Neutron and photon flux densities were measured using neutron activation analysis (NAA) and semiconductor spectrometry. The secondary dose was estimated applying the fluence-to-dose conversion coefficients. The main contribution to the secondary dose is associated with fast neutrons. The main sources of γ-radiation are the following: {sup 56}Mn in the stainless steel and {sup 187}W of the collimation system as well as positron emitters, activated via (n,γ) and (γ,n) processes, respectively. In addition to 12 Gy of therapeutic dose, the patient could receive 57.43 mSv in the studied conditions, including 4.63 μSv from activated radionuclides. Neutron dose is mainly influenced by the time of beam emission. However, it is moderated by long source-surface distances (SSD) and application of plexiglass plates covering the patient body during treatment. Secondary radiation gives the whole body a dose, which should be taken into consideration especially when one fraction of irradiation does not cover the whole body at once. (orig.) [German] Die zusaetzliche Dosis durch sekundaere Neutronen- und γ-Strahlung waehrend der Ganzkoerperbestrahlung mit Roentgenstrahlung aus medizinischen Linearbeschleunigern wurde abgeschaetzt. Bei der Emission hochenergetischer Strahlen zur Teletherapie finden hauptsaechlich im Beschleuniger

  19. Radiation as an immunological adjuvant: current evidence on dose and fractionation

    International Nuclear Information System (INIS)

    Demaria, Sandra; Formenti, Silvia C.

    2012-01-01

    Ionizing radiation to a cancer site has the ability to convert the irradiated tumor in an immunogenic hub. However, radiation is a complex modifier of the tumor microenvironment and, by itself, is seldom sufficient to induce a therapeutically significant anti-tumor immune response, since it can also activate immune suppressive pathways. While several combinations of local radiation and immunotherapy have been shown in pre-clinical models to induce powerful anti-tumor immunity, the optimal strategy to achieve this effect remains to be defined. When used in vivo, radiation effects on tumors depend on the dose per fraction applied, the number of fractions used, and the total dose. Moreover, the interplay of these three variables is contingent upon the tumor setting studied, both in pre-clinical and clinical applications. To enable repair of the collateral damage to the normal tissue, radiation is usually given in multiple fractions, usually of 2 Gy. Generally, the use of larger fractions is limited to stereotactic applications, whereby optimal immobilization reduces inter- and intrafraction movement and permits a very conformal delivery of dose to the target, with optimal exclusion of normal tissue. Translation of the partnership of radiation and immunotherapy to the clinic requires a careful consideration of the radiation regimens used. To date, little is known on whether different dose/fractionation regimens have a specific impact on the anti-tumor immune response. Most experiments combining the two modalities were conducted with single fractions of radiotherapy. However, there is at least some evidencethat when combined with some specific immunotherapy approaches, the ability of radiation to promote anti-tumor immunity is dependent on the dose and fractionation employed. We critically review the available in vitro and in vivo data on this subject and discuss the potential impact of fractionation on the ability of radiation to synergize with immunotherapy.

  20. Total proteins and protein fractions levels in pregnant rats subjected to whole-body gamma irradiation

    International Nuclear Information System (INIS)

    Mansour, M.A.; Roushdy, H.M.; Mazhar, F.M.; Abu-Gabal, H.A.

    1986-01-01

    A total number of 180 mature rats (120 females and 60 males) weighing from 120-140 g were used to study the effect of two doses (2 and 4 Gy) whole-body gamma irradiation on the level of total protein and protein fractions in serum of pregnant rats during the period of organogenesis. It was found that the levels of total protein, albumin and gamma globulins significantly decreased according to the doses of exposure. The levels of alpha and beta globulins significantly increased more in the serum of rats exposed to 2 Gy than in rats exposed to 4 Gy. The level of A/G ratio significantly decreased more in the serum of rats exposed to 2Gy than in those exposed to 4 Gy

  1. Dose equivalent distributions in the AAEC total body nitrogen facility

    International Nuclear Information System (INIS)

    Allen, B.J.; Bailey, G.M.; McGregor, B.J.

    1985-01-01

    The incident neutron dose equivalent in the AAEC total body nitrogen facility is measured by a calibrated remmeter. Dose equivalent rates and distributions are calculated by Monte Carlo techniques which take account of the secondary neutron flux from the collimator. Experiment and calculation are found to be in satisfactory agreement. The effective dose equivalent per exposure is determined by weighting organ doses, and the potential detriment per exposure is calculated from ICRP risk factors

  2. Reemergence of apoptotic cells between fractionated doses in irradiated murine tumors

    International Nuclear Information System (INIS)

    Meyn, R.E.; Hunter, N.R.; Milas, L.

    1994-01-01

    The purpose of this investigation was to follow up our previous studies on the development of apoptosis in irradiated murine tumors by testing whether an apoptotic subpopulation of cells reemerges between fractionated exposures. Mice bearing a murine ovarian carcinoma, OCa-I, were treated in vivo with two fractionation protocols: two doses of 12.5 Gy separated by various times out to 5 days and multiple daily fractions of 2.5 Gy. Animals were killed 4 h after the last dose in each protocol, and the percent apoptosis was scored from stained histological sections made from the irradiated tumors according to the specific features characteristic of this mode of cell death. The 12.5+12.5 Gy protocol yielded a net total percent apoptosis of about 45% when the two doses were separated by 5 days (total dose = 25 Gy), whereas the 2.5 Gy per day protocol yielded about 50% net apoptotic cells when given for 5 days (total dose = 12.5 Gy). These values are to be compared to the value of 36% apoptotic cells that is yielded by large single doses (> 25 Gy). Thus, these results indicate that an apoptotic subpopulation of cells reemerged between the fractions in both protocols, but the kinetics appeared to be delayed in the 12.5+12.5 Gy vs. the multiple 2.5 Gy protocol. This reemergence of cells with the propensity for radiation-induced apoptosis between fractionated exposures is consistent with a role for this mode of cell death in the response of tumors to radiotherapy and may represent the priming of a new subpopulation of tumor cells for apoptosis as part of normal tumor homeostasis to counterbalance cell division. 25 refs., 3 figs., 1 tab

  3. Correct statistical evaluation for total dose in rural settlement

    International Nuclear Information System (INIS)

    Vlasova, N.G.; Skryabin, A.M.

    2001-01-01

    Statistical evaluation of dose reduced to the determination of an average value and its error. If an average value of a total dose in general can be determined by simple summarizing of the averages of its external and internal components, the evaluation of an error can be received only from its distribution. Herewith, considering that both components of the dose are interdependent, to summarize their distributions, as a last ones of a random independent variables, is incorrect. It follows that an evaluation of the parameters of the total dose distribution, including an error, in general, cannot be received empirically, particularly, at the lack or absence of the data on one of the components of the last one, that constantly is happens in practice. If the evaluation of an average for total dose was defined somehow, as the best, as an average of a distribution of the values of individual total doses, as summarizing the individual external and internal doses by the random type, that an error of evaluation had not been produced. The methodical approach to evaluation of the total dose distribution at the lack of dosimetric information was designed. The essence of it is original way of an interpolation of an external dose distribution, using data on an internal dose

  4. Effect of time, dose and fractionation on local control of nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Lee, Anne W.M.; Chan, David K.K.; Poon, Y.F.; Foo, William; Law, Stephen C.K.; O, S.K.; Tung, Stewart Y.; Fowler, Jack F.; Chappell, Rick

    1995-01-01

    To study the effect of radiation factors on local control of nasopharyngeal carcinoma, 1008 patients with similarly staged T1N0-3M0 disease (Ho's classification) were retrospectively analyzed. All patients were treated by megavoltage irradiation alone using the same technique. Four different fractionation schedules had been used sequentially during 1976-1985: with total dose ranging from 45.6 to 60 Gy and fractional dose from 2.5 to 4.2 Gy. The median overall time was 39 days (range = 38-75 days). Both for the whole series and 763 patients with nodal control, total dose was the most important radiation factor. The hazard of local failure decreased by 9% per additional Gy (p < 0.01). Biological equivalents expressed in terms of Biologically Effective Dose or Nominal Standard Dose also showed strong correlation. Fractional dose had no significant impact. The effect of overall treatment time was insignificant for the whole series, but almost reached statistical significance for those with nodal control (p = 0.06). Further study is required for elucidation, as 85% of patients completed treatment within a very narrow range (38-42 days), and the possible hazard is clinically too significant to be ignored

  5. Results of high intensity afterloading irradiation with 192 iridium in the therapy of genital tumors in women under different dose rates, fractionations and total doses in comparison with conventional radium contact irradiation. Ergebnisse der High-Intensity-Afterloadingbestrahlung mit 192 Iridium in der Therapie von Genitaltumoren der Frau unter verschiedenen Dosisleistungen, Fraktionierungen und Gesamtdosen im Vergleich mit konventioneller Radiumkontaktbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Giers, G

    1986-05-07

    In comparison to conventional radium therapy are to be evaluated the results of the high intensity afterloading technique with the help of the parameters survial rate and complication rate. Thereby were included in the examination 4 documentations of results (collum, cervix stump, corpus and vaginal carcinoma) with altogether 742 patients with 2806 single irradiations and an evaluation of the therapy after several modifications of the therapy schemes. The 5-year survival rate was in the case of collum carcinoma: 68.4%, cervix stump: 50%, corpus carcinoma: 76%, and vaginal carcinoma: 66.6%. The corresponding 3-year survival rates were: 74.2%, 80%, 84% and 70% with primary irradiation. Only with cervix stump carcinoma were the values for post-operative irradiation. The description of the irradiation results showed, that with the changing of the fractionation mode and the dose level in collum and corpus carcinoma the irreversible complications as an expression of the success of a new therapy were reduced. The for now best suited therapy schema (fractionation and dosing) are described. (TRV).

  6. Dose rate-dependent marrow toxicity of TBI in dogs and marrow sparing effect at high dose rate by dose fractionation.

    Science.gov (United States)

    Storb, R; Raff, R F; Graham, T; Appelbaum, F R; Deeg, H J; Schuening, F G; Sale, G; Seidel, K

    1999-01-01

    We evaluated the marrow toxicity of 200 and 300 cGy total-body irradiation (TBI) delivered at 10 and 60 cGy/min, respectively, in dogs not rescued by marrow transplant. Additionally, we compared toxicities after 300 cGy fractionated TBI (100 cGy fractions) to that after single-dose TBI at 10 and 60 cGy/min. Marrow toxicities were assessed on the basis of peripheral blood cell count changes and mortality from radiation-induced pancytopenia. TBI doses studied were just below the dose at which all dogs die despite optimal support. Specifically, 18 dogs were given single doses of 200 cGy TBI, delivered at either 10 (n=13) or 60 (n=5) cGy/min. Thirty-one dogs received 300 cGy TBI at 10 cGy/min, delivered as either single doses (n=21) or three fractions of 100 cGy each (n=10). Seventeen dogs were given 300 cGy TBI at 60 cGy/min, administered either as single doses (n=5) or three fractions of 100 cGy each (n=10). Within the limitations of the experimental design, three conclusions were drawn: 1) with 200 and 300 cGy single-dose TBI, an increase of dose rate from 10 to 60 cGy/min, respectively, caused significant increases in marrow toxicity; 2) at 60 cGy/min, dose fractionation resulted in a significant decrease in marrow toxicities, whereas such a protective effect was not seen at 10 cGy/min; and 3) with fractionated TBI, no significant differences in marrow toxicity were seen between dogs irradiated at 60 and 10 cGy/min. The reduced effectiveness of TBI when a dose of 300 cGy was divided into three fractions of 100 cGy or when dose rate was reduced from 60 cGy/min to 10 cGy/min was consistent with models of radiation toxicity that allow for repair of sublethal injury in DNA.

  7. Simulation experiment on total ionization dose effects of linear CCD

    International Nuclear Information System (INIS)

    Tang Benqi; Zhang Yong; Xiao Zhigang; Wang Zujun; Huang Shaoyan

    2004-01-01

    We carry out the ionization radiation experiment of linear CCDs operated in unbiased, biased, biased and driven mode respectively by Co-60 γ source with our self-designed test system, and offline test the Dark signal and Saturation voltage and SNR varied with total dose for TCD132D, and get some valuable results. On the basis of above work, we set forth a primary experiment approaches to simulate the total dose radiation effects of charge coupled devices. (authors)

  8. Short-term irradiation of the glioblastoma with high-dosed fractions

    International Nuclear Information System (INIS)

    Hinkelbein, W.; Bruggmoser, G.; Schmidt, M.; Wannenmacher, M.

    1984-01-01

    Compared to surgery alone, postoperative radiotherapy leads with glioblastomas (grade IV gliomas) to a significant improvement of the therapeutic results. The prolongation of survival time, however, is to a large extent compensated by the therapy itself (it normally implicates hospitalisation). Therefore, we tested the efficiency of rapid course irradiation with high fractions. 70 patients were treated daily with individual fractions of 3.5 Gy, 4 to 6 fractions per week. The entire dose amounted to 31.5 to 38.5 Gy. The average survival time was 33.5 weeks corresponding to the survival time known from the combined surgical and radiotherapeutical treatment of glioblastomas. An effective increase in therapy-free survival time seems possible, especially when the entire focal dose does not exceed 35 Gy. It is remarkable that the patients with the maximum exposure did not have the longest survival times and rates. Living conditions for the patients were similar to those with conventional fractioning, or even better. Rapid course irradiation with high fractions and a limited total dose (35 Gy) presently is - apart from the accelerated superfractioning - a successful measure to prolong the therapyfree survival time for patients with grade IV gliomas. (orig.) [de

  9. Acute hematological tolerance to multiple fraction, whole body, low dose irradiation in an experimental murine system

    International Nuclear Information System (INIS)

    Melamed, J.S.; Chen, M.G.; Brown, J.W.; Katagiri, C.A.

    1980-01-01

    Using a dose fractionation scheme patterned after the current regimen for treatment of disseminated non-Hodgkin lymphoma, the authors studied the effects of irradation on progenitor and effector cells for hematopoiesis in five-month-old BC3F 1 mice. Fractions of 20 or 50 rad (0.2 or 0.5 Gy) total body irradation were given twice weekly to a final total dose of 200 or 500 rad (2 or 5 Gy), respectively. Weekly assays revealed a marked, sustained depression of stem cell activity, measured as numbers of spleen colony-forming units (CFU-S) and in vitro colony-forming cells (CFU-C), without corresponding depression of effector cells (red and white cells, and platelets). The lack of correlation between numbers of stem cells and peripheral elements is relevant to clinical assessment of marrow reserve

  10. Clinical applicability of biologically effective dose calculation for spinal cord in fractionated spine stereotactic body radiation therapy

    International Nuclear Information System (INIS)

    Lee, Seung Heon; Lee, Kyu Chan; Choi, Jinho; Ahn, So Hyun; Lee, Seok Ho; Sung, Ki Hoon; Kil, Se Hee

    2015-01-01

    The aim of the study was to investigate whether biologically effective dose (BED) based on linear-quadratic model can be used to estimate spinal cord tolerance dose in spine stereotactic body radiation therapy (SBRT) delivered in 4 or more fractions. Sixty-three metastatic spinal lesions in 47 patients were retrospectively evaluated. The most frequently prescribed dose was 36 Gy in 4 fractions. In planning, we tried to limit the maximum dose to the spinal cord or cauda equina less than 50% of prescription or 45 Gy 2/2 . BED was calculated using maximum point dose of spinal cord. Maximum spinal cord dose per fraction ranged from 2.6 to 6.0 Gy (median 4.3 Gy). Except 4 patients with 52.7, 56.4, 62.4, and 67.9 Gy 2/2 , equivalent total dose in 2-Gy fraction of the patients was not more than 50 Gy 2/2 (12.1–67.9, median 32.0). The ratio of maximum spinal cord dose to prescription dose increased up to 82.2% of prescription dose as epidural spinal cord compression grade increased. No patient developed grade 2 or higher radiation-induced spinal cord toxicity during follow-up period of 0.5 to 53.9 months. In fractionated spine SBRT, BED can be used to estimate spinal cord tolerance dose, provided that the dose per fraction to the spinal cord is moderate, e.g. < 6.0 Gy. It appears that a maximum dose of up to 45–50 Gy 2/2 to the spinal cord is tolerable in 4 or more fractionation regimen

  11. Dependence of total dose response of bipolar linear microcircuits on applied dose rate

    International Nuclear Information System (INIS)

    McClure, S.; Will, W.; Perry, G.; Pease, R.L.

    1994-01-01

    The effect of dose rate on the total dose radiation hardness of three commercial bipolar linear microcircuits is investigated. Total dose tests of linear bipolar microcircuits show larger degradation at 0.167 rad/s than at 90 rad/s even after the high dose rate test is followed by a room temperature plus a 100 C anneal. No systematic correlation could be found for degradation at low dose rate versus high dose rate and anneal. Comparison of the low dose rate with the high dose rate anneal data indicates that MIL-STD-883, method 1019.4 is not a worst-case test method when applied to bipolar microcircuits for low dose rate space applications

  12. Total body irradiation in bone marrow transplantation: the influence of fractionation and delay of marrow infusion

    International Nuclear Information System (INIS)

    Lichter, A.S.; Tracy, D.; Lam, W.C.; Order, S.E.

    1980-01-01

    Bone marrow transplantation (BMT) after total body irradiation (TBI) and cyclophosphamide is being employed increasingly in the therapy of end stage leukemia. Interstitial pneumonitis (IP) represents a major acute toxicity after allogeneic transplantation. A more rapid reconstitution of lymphoid organs and bone marrow post transplant may result in increased immune competence and hence fewer opportunistic pulmonary infections and IP. By delaying the infusion of marrow to 72 hr after TBI (1250 rad at 7.5 rad/min) instead of the customary 24 hr, we can demonstrate an increase in initial repopulation of thymus, spleen and bone marrow, with syngeneic transplants in Lewis rats. Interstitial pneumonitis may also be caused, in part, by the pulmonary toxicity of large single exposures of TBI. Clinical and laboratory data suggest that fractionated TBI may be less toxic to the lung. When fractionated TBI (625 rad x 2, 7.5 rad/min) is compared to single dose TBI (1250 rad, 7.5 rad/min), and increased initial repopulation of lymphoid organs is observed when fractionated therapy is employed. Delay in marrow infusion and fractionation of TBI exposure may have clinical advantages in patients who receive BMT

  13. Prediction of midline dose from entrance ad exit dose using OSLD measurements for total irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Heon; Park, Jong Min; Park, So Yeon; Chun, Min Soo; Han, Ji Hye; Cho, Jin Dong; Kim, Jung In [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-06-15

    This study aims to predict the midline dose based on the entrance and exit doses from optically stimulated luminescence detector (OSLD) measurements for total body irradiation (TBI). For TBI treatment, beam data sets were measured for 6 MV and 15 MV beams. To evaluate the tissue lateral effect of various thicknesses, the midline dose and peak dose were measured using a solid water phantom (SWP) and ion chamber. The entrance and exit doses were measured using OSLDs. OSLDs were attached onto the central beam axis at the entrance and exit surfaces of the phantom. The predicted midline dose was evaluated as the sum of the entrance and exit doses by OSLD measurement. The ratio of the entrance dose to the exit dose was evaluated at various thicknesses. The ratio of the peak dose to the midline dose was 1.12 for a 30 cm thick SWP at both energies. When the patient thickness is greater than 30 cm, the 15 MV should be used to ensure dose homogeneity. The ratio of the entrance dose to the exit dose was less than 1.0 for thicknesses of less than 30 cm and 40 cm at 6 MV and 15 MV, respectively. Therefore, the predicted midline dose can be underestimated for thinner body. At 15 MV, the ratios were approximately 1.06 for a thickness of 50 cm. In cases where adult patients are treated with the 15 MV photon beam, it is possible for the predicted midline dose to be overestimated for parts of the body with a thickness of 50 cm or greater. The predicted midline dose and OSLD-measured midline dose depend on the phantom thickness. For in-vivo dosimetry of TBI, the measurement dose should be corrected in order to accurately predict the midline dose.

  14. Pulsed total dose damage effect experimental study on EPROM

    International Nuclear Information System (INIS)

    Luo Yinhong; Yao Zhibin; Zhang Fengqi; Guo Hongxia; Zhang Keying; Wang Yuanming; He Baoping

    2011-01-01

    Nowadays, memory radiation effect study mainly focus on functionality measurement. Measurable parameters is few in china. According to the present situation, threshold voltage testing method was presented on floating gate EPROM memory. Experimental study of pulsed total dose effect on EPROM threshold voltage was carried out. Damage mechanism was analysed The experiment results showed that memory cell threshold voltage negative shift was caused by pulsed total dose, memory cell threshold voltage shift is basically coincident under steady bias supply and no bias supply. (authors)

  15. Estimation of the effectivity of gamma teletherapy with fractionated daily doses in inoperable malignant tumors

    International Nuclear Information System (INIS)

    Mardynskij, Yu.S.; Leskov, V.P.

    1982-01-01

    131 patients with lung, esophagus, rectum and mandibulofacial tumors, most of them being inoperable, were treated with fractionated gamma teletherapy. The daily focus dose of 2-2.2 Gy was applied in 2 fractions with an interval of 4-6 h. The total focus dose of one course of treatment was 40-70 Gy. In 56 patients (42.7%) a complete regression of the tumors and of the increased regional lymph nodes was obtained. The irradiation by the mentioned technique showed the highest effectivity for tumors of the lung and the esophagus. The diminished frequency and an easier progress of the radiation reactions are important because they often prevent to carry out a radical therapy. (author)

  16. Effects of low-dose continuously fractionated X-ray irradiation on murine peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Xie Yi; Zhang Hong; Dang Bingrong; Hao Jifang; Guo Hongyun; Wang Xiaohu

    2007-01-01

    For estimating biological risks from low doses continual irradiation, we investigated the effects of exposure to continuously fractionated X-rays on murine immune system. The BALB/c mice were irradiated with 0.07Gy at the first day and 0.08 Gy/d in the following 12 days at a dose rate of 0.2 Gy/min. The peripheral blood lymphocyte cycle and death were determined by flow cytometry at the cumulative doses of 0, 0.07, 0.23, 0.39, 0.55, 0.71, 0.87 and 1.03 Gy respectively. The results showed that the cycle of peripheral blood lymphocyte was arrested in G 0 /G 1 at cumulative doses of 0.07, 0.23, 0.71 and 0.87 Gy, and in G 2 /M at cumulative doses of 0.39 and 1.03 Gy; the percentage of death of peripheral blood lymphocyte was ascended with dose increasing, and reached the death peak at cumulative doses of 0.71 Gy. The results suggested that low doses continual X-rays total-body irradiated could result in changes of cellular cycle and death, and some damages to immunocytes, which accorded to linear square model. (authors)

  17. Effect of fractionated versus unfractionated total body irradiation on the growth of the BN acute myelocytic leukemia

    International Nuclear Information System (INIS)

    Hagenbeek, A.; Martens, A.C.M.

    1981-01-01

    The efficacy of various total body irradiation (TBI) regimens prior to bone marrow transplantation was evaluated in a rat model for acute myelocytic leukemia (Dq = 85.1 cGy gamma ; N = 3.7). Using high dose rate gamma-irradiation (115 cGy/min), fractionated TBI with large total daily doses (400 to 600 cGy), either given as acute doses or as split doses at 8 hr intervals, was most effective. Split doses (2 fractions per day) offered no additional advantage. At the most, a 4 log leukemic cell kill was induced. No lethal toxicity was observed. Nine-hundred cGy flash TBI had a similar anti-tumor effect, but with this regimen almost half of the rats died from radiation-induced toxicity (lungs and gastro-intestinal tract). The results are explained in terms of differences between normal and leukemic cells as regards (a) repair of sublethal damage; and (b) repopulation. Low dose rate continuous gamma-irradiation (0.26 cGy/min) with total doses ranging from 900 to 2000 cGy was also quite effective. Maximally a 4 log cell kill was obtained. With 2000 cGy, 50% of the rats died from the gastro-intestinal tract-syndrome. In addition to the major role played by chemotherapy, TBI is mainly of importance in sterilizing the various sanctuaries in the body which contain leukemic cells anatomically resistant to most cytostatic agents

  18. High-Dose-Rate Brachytherapy Boost for Prostate Cancer: Comparison of Two Different Fractionation Schemes

    International Nuclear Information System (INIS)

    Kaprealian, Tania; Weinberg, Vivian; Speight, Joycelyn L.; Gottschalk, Alexander R.; Roach, Mack; Shinohara, Katsuto; Hsu, I.-Chow

    2012-01-01

    Purpose: This is a retrospective study comparing our experience with high-dose-rate (HDR) brachytherapy boost for prostate cancer, using two different fractionation schemes, 600 cGy × 3 fractions (patient group 1) and 950 cGy × 2 fractions (patient group 2). Methods and Materials: A total of 165 patients were treated for prostate cancer using external beam radiation therapy up to a dose of 45 Gy, followed by an HDR brachytherapy prostate radiation boost. Between July 1997 and Nov 1999, 64 patients were treated with an HDR boost of 600 cGy × 3 fractions; and between June 2000 and Nov 2005, 101 patients were treated with an HDR boost of 950 cGy × 2 fractions. All but 9 patients had at least one of the following risk features: pretreatment prostate-specific antigen (PSA) level >10, a Gleason score ≥7, and/or clinical stage T3 disease. Results: Median follow-up was 105 months for group 1 and 43 months for group 2. Patients in group 2 had a greater number of high-risk features than group 1 (p = 0.02). Adjusted for comparable follow-up, there was no difference in biochemical no-evidence-of-disease (bNED) rate between the two fractionation scheme approaches, with 5-year Kaplan-Meier estimates of 93.5% in group 1 and 87.3% in group 2 (p = 0.19). The 5-year estimates of progression-free survival were 86% for group 1 and 83% for group 2 (p = 0.53). Among high-risk patients, there were no differences in bNED or PFS rate due to fractionation. Conclusions: Results were excellent for both groups. Adjusted for comparable follow-up, no differences were found between groups.

  19. Fractionated total lymphoid irradiation as preparative immunosuppression in high risk renal transplantation

    International Nuclear Information System (INIS)

    Najarian, J.S.; Ferguson, R.M.; Sutherland, D.E.; Slavin, S.; Kim, T.; Kersey, J.; Simmons, R.L.

    1982-01-01

    Twenty-two patients at high risk to reject renal allografts have been treated with fractionated total lymphoid irradiation (FTLI) prior to transplantation of primary (2), secondary (16) or tertiary (4) renal allografts. All patients undergoing retransplantation had rapidly rejected previous grafts. At 24 months following transplantation, 72% of grafts were functioning in the TLI group compared with a 38% graft function in an historical control group of recipients receiving secondary or tertiary grafts and treated with conventional immunosuppression. Important variables in determining success of transplantation following fractionated TLI include the dose of TLI, the interval from radiation to transplantation, and maintenance post-transplant immunosuppressive therapy. Optimal results were achieved with 2500 rads delivered in 100 rad fractions followed by transplantation within two weeks, and a tapering prednisone schedule and maintenance azathioprine post-transplantation. Seventeen patients had significant complications of the radiation treatment and there was one death, prior to transplantation, associated with pneumonitis. In vitro assessment of immune function demonstrated marked peripheral T cell depletion and loss of in vitro responsiveness to mitogen and allogeneic stimulation following FTLI. The administration of donor bone marrow at the time of transplantation did not produce chimerism. The results suggest that when properly utilized FTLI can produce effective adjunctive immunosuppression for clinical transplantation

  20. Linear-quadratic model underestimates sparing effect of small doses per fraction in rat spinal cord

    International Nuclear Information System (INIS)

    Shun Wong, C.; Toronto University; Minkin, S.; Hill, R.P.; Toronto University

    1993-01-01

    The application of the linear-quadratic (LQ) model to describe iso-effective fractionation schedules for dose fraction sizes less than 2 Gy has been controversial. Experiments are described in which the effect of daily fractionated irradiation given with a wide range of fraction sizes was assessed in rat cervical spine cord. The first group of rats was given doses in 1, 2, 4, 8 and 40 fractions/day. The second group received 3 initial 'top-up'doses of 9 Gy given once daily, representing 3/4 tolerance, followed by doses in 1, 2, 10, 20, 30 and 40 fractions/day. The fractionated portion of the irradiation schedule therefore constituted only the final quarter of the tolerance dose. The endpoint of the experiments was paralysis of forelimbs secondary to white matter necrosis. Direct analysis of data from experiments with full course fractionation up to 40 fractions/day (25.0-1.98 Gy/fraction) indicated consistency with the LQ model yielding an α/β value of 2.41 Gy. Analysis of data from experiments in which the 3 'top-up' doses were followed by up to 10 fractions (10.0-1.64 Gy/fraction) gave an α/β value of 3.41 Gy. However, data from 'top-up' experiments with 20, 30 and 40 fractions (1.60-0.55 Gy/fraction) were inconsistent with LQ model and gave a very small α/β of 0.48 Gy. It is concluded that LQ model based on data from large doses/fraction underestimates the sparing effect of small doses/fraction, provided sufficient time is allowed between each fraction for repair of sublethal damage. (author). 28 refs., 5 figs., 1 tab

  1. Calculation of midplane dose for total body irradiation from entrance and exit dose MOSFET measurements.

    Science.gov (United States)

    Satory, P R

    2012-03-01

    This work is the development of a MOSFET based surface in vivo dosimetry system for total body irradiation patients treated with bilateral extended SSD beams using PMMA missing tissue compensators adjacent to the patient. An empirical formula to calculate midplane dose from MOSFET measured entrance and exit doses has been derived. The dependency of surface dose on the air-gap between the spoiler and the surface was investigated by suspending a spoiler above a water phantom, and taking percentage depth dose measurements (PDD). Exit and entrances doses were measured with MOSFETs in conjunction with midplane doses measured with an ion chamber. The entrance and exit doses were combined using an exponential attenuation formula to give an estimate of midplane dose and were compared to the midplane ion chamber measurement for a range of phantom thicknesses. Having a maximum PDD at the surface simplifies the prediction of midplane dose, which is achieved by ensuring that the air gap between the compensator and the surface is less than 10 cm. The comparison of estimated midplane dose and measured midplane dose showed no dependence on phantom thickness and an average correction factor of 0.88 was found. If the missing tissue compensators are kept within 10 cm of the patient then MOSFET measurements of entrance and exit dose can predict the midplane dose for the patient.

  2. Methods of assessing total doses integrated across pathways

    International Nuclear Information System (INIS)

    Grzechnik, M.; Camplin, W.; Clyne, F.; Allott, R.; Webbe-Wood, D.

    2006-01-01

    Calculated doses for comparison with limits resulting from discharges into the environment should be summed across all relevant pathways and food groups to ensure adequate protection. Current methodology for assessments used in the radioactivity in Food and the Environment (R.I.F.E.) reports separate doses from pathways related to liquid discharges of radioactivity to the environment from those due to gaseous releases. Surveys of local inhabitant food consumption and occupancy rates are conducted in the vicinity of nuclear sites. Information has been recorded in an integrated way, such that the data for each individual is recorded for all pathways of interest. These can include consumption of foods, such as fish, crustaceans, molluscs, fruit and vegetables, milk and meats. Occupancy times over beach sediments and time spent in close proximity to the site is also recorded for inclusion of external and inhalation radiation dose pathways. The integrated habits survey data may be combined with monitored environmental radionuclide concentrations to calculate total dose. The criteria for successful adoption of a method for this calculation were: Reproducibility can others easily use the approach and reassess doses? Rigour and realism how good is the match with reality?Transparency a measure of the ease with which others can understand how the calculations are performed and what they mean. Homogeneity is the group receiving the dose relatively homogeneous with respect to age, diet and those aspects that affect the dose received? Five methods of total dose calculation were compared and ranked according to their suitability. Each method was labelled (A to E) and given a short, relevant name for identification. The methods are described below; A) Individual doses to individuals are calculated and critical group selection is dependent on dose received. B) Individual Plus As in A, but consumption and occupancy rates for high dose is used to derive rates for application in

  3. Comparison of Different Fractionation Schedules Toward a Single Fraction in High-Dose-Rate Brachytherapy as Monotherapy for Low-Risk Prostate Cancer Using 3-Dimensional Radiobiological Models

    Energy Technology Data Exchange (ETDEWEB)

    Mavroidis, Panayiotis, E-mail: mavroidis@uthscsa.edu [Department of Radiation Oncology, University of Texas Health Sciences Center, San Antonio, Texas (United States); Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, Stockholm (Sweden); Milickovic, Natasa [Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach GmbH, Offenbach (Germany); Cruz, Wilbert F. [Department of Radiation Oncology, University of Texas Health Sciences Center, San Antonio, Texas (United States); Tselis, Nikolaos [Strahlenklinik, Klinikum Offenbach GmbH, Offenbach (Germany); Karabis, Andreas [Pi-Medical Ltd., Athens (Greece); Stathakis, Sotirios; Papanikolaou, Nikos [Department of Radiation Oncology, University of Texas Health Sciences Center, San Antonio, Texas (United States); Zamboglou, Nikolaos [Strahlenklinik, Klinikum Offenbach GmbH, Offenbach (Germany); Baltas, Dimos [Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach GmbH, Offenbach (Germany); Nuclear and Particle Physics Section, Physics Department, University of Athens, Athens (Greece)

    2014-01-01

    Purpose: The aim of the present study was the investigation of different fractionation schemes to estimate their clinical impact. For this purpose, widely applied radiobiological models and dosimetric measures were used to associate their results with clinical findings. Methods and Materials: The dose distributions of 12 clinical high-dose-rate brachytherapy implants for prostate were evaluated in relation to different fractionation schemes. The fractionation schemes compared were: (1) 1 fraction of 20 Gy; (2) 2 fractions of 14 Gy; (3) 3 fractions of 11 Gy; and (4) 4 fractions of 9.5 Gy. The clinical effectiveness of the different fractionation schemes was estimated through the complication-free tumor control probability (P{sub +}), the biologically effective uniform dose, and the generalized equivalent uniform dose index. Results: For the different fractionation schemes, the tumor control probabilities were 98.5% in 1 × 20 Gy, 98.6% in 2 × 14 Gy, 97.5% in 3 × 11 Gy, and 97.8% in 4 × 9.5 Gy. The corresponding P{sub +} values were 88.8% in 1 × 20 Gy, 83.9% in 2 × 14 Gy, 86.0% in 3 × 11 Gy, and 82.3% in 4 × 9.5 Gy. With use of the fractionation scheme 4 × 9.5 Gy as reference, the isoeffective schemes regarding tumor control for 1, 2, and 3 fractions were 1 × 19.68 Gy, 2 × 13.75 Gy, and 3 × 11.05 Gy. The optimum fractionation schemes for 1, 2, 3, and 4 fractions were 1 × 19.16 Gy with a P{sub +} of 91.8%, 2 × 13.2 Gy with a P{sub +} of 89.6%, 3 × 10.6 Gy with a P{sub +} of 88.4%, and 4 × 9.02 Gy with a P{sub +} of 86.9%. Conclusions: Among the fractionation schemes 1 × 20 Gy, 2 × 14 Gy, 3 × 11 Gy, and 4 × 9.5 Gy, the first scheme was more effective in terms of P{sub +}. After performance of a radiobiological optimization, it was shown that a single fraction of 19.2 to 19.7 Gy (average 19.5 Gy) should produce at least the same benefit as that given by the 4 × 9.5 Gy scheme, and it should reduce the expected total complication probability by

  4. Study of total ionization dose effects in electronic devices

    International Nuclear Information System (INIS)

    Nidhin, T.S.; Bhattacharyya, Anindya; Gour, Aditya; Behera, R.P.; Jayanthi, T.

    2018-01-01

    Radiation effects in electronic devices are a major challenge in the dependable application developments of nuclear power plant instrumentation and control systems. The main radiation effects are total ionization dose (TID) effects, displacement damage dose (DDD) effects and single event effects (SEE). In this study, we are concentrating on TID effects in electronic devices. The focus of the study is mainly on SRAM based field programmable gate arrays (FPGA) along with that the devices of our interest are voltage regulators, flash memory and optocoupler. The experiments are conducted by exposing the devices to gamma radiation in power off condition and the degradation in the performances are analysed

  5. 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)

  6. Low-dose-rate total lymphoid irradiation: a new method of rapid immunosuppression

    International Nuclear Information System (INIS)

    Blum, J.E.; de Silva, S.M.; Rachman, D.B.; Order, S.E.

    1988-01-01

    Total Lymphoid Irradiation (TLI) has been successful in inducing immunosuppression in experimental and clinical applications. However, both the experimental and clinical utility of TLI are hampered by the prolonged treatment courses required (23 days in rats and 30-60 days in humans). Low-dose-rate TLI has the potential of reducing overall treatment time while achieving comparable immunosuppression. This study examines the immunosuppressive activity and treatment toxicity of conventional-dose-rate (23 days) vs low-dose-rate (2-7 days) TLI. Seven groups of Lewis rats were given TLI with 60Co. One group was treated at conventional-dose-rates (80-110 cGy/min) and received 3400 cGy in 17 fractions over 23 days. Six groups were treated at low-dose-rate (7 cGy/min) and received total doses of 800, 1200, 1800, 2400, 3000, and 3400 cGy over 2-7 days. Rats treated at conventional-dose-rates over 23 days and at low-dose-rate over 2-7 days tolerated radiation with minimal toxicity. The level of immunosuppression was tested using allogeneic (Brown-Norway) skin graft survival. Control animals retained allogeneic skin grafts for a mean of 14 days (range 8-21 days). Conventional-dose-rate treated animals (3400 cGy in 23 days) kept their grafts 60 days (range 50-66 days) (p less than .001). Low-dose-rate treated rats (800 to 3400 cGy total dose over 2-7 days) also had prolongation of allogeneic graft survival times following TLI with a dose-response curve established. The graft survival time for the 3400 cGy low-dose-rate group (66 days, range 52-78 days) was not significantly different from the 3400 cGy conventional-dose-rate group (p less than 0.10). When the total dose given was equivalent, low-dose-rate TLI demonstrated an advantage of reduced overall treatment time compared to conventional-dose-rate TLI (7 days vs. 23 days) with no increase in toxicity

  7. Single-dose and fractionated irradiation of four human lung cancer cell lines in vitro

    International Nuclear Information System (INIS)

    Brodin, O.; Lennartsson, L.; Nilsson, S.

    1991-01-01

    Four established human lung cancer cell lines were exposed to single-dose irradiation. The survival curves of 2 small cell lung carcinomas (SCLC) were characterized by a limited capacity for repair with small and moderate shoulders with extrapolation numbers (n) of 1.05 and 1.60 respectively. Two non-small cell lung carcinoma (NSCLC) cell lines, one squamous cell (SQCLC) and one large cell (LCLC) had large shoulders with n-values of 73 and 15 respectively. The radiosensitivity when measured as D 0 did not, however, differ as much from cell line to cell line, with values from 1.22 to 1.65. The surviving fraction after 2 Gy (SF2) was 0.24 and 0.42 respectively in the SCLC cell lines and 0.90 and 0.88 respectively in the NSCLC cell lines. Fractionated irradiation delivered according to 3 different schedules was also investigated. All the schedules delivered a total dose of 10 Gy in 5 days and were applied in 1, 2 and 5 Gy dose fractions respectively. Survival followed the pattern found after single-dose irradiation; it was lowest in the SCLC cell line with the lowest SF and highest in the two NSCLC cell lines. In the SCLC cell lines all schedules were approximately equally efficient. In the LCLC and in the SQCLC cell lines, the 5 Gy schedule killed more cells than the 1 and 2 Gy schedules. The results indicate that the size of the shoulder of the survival curve is essential when choosing the most tumoricidal fractionation schedule. (orig.)

  8. Anticonvulsant properties of the total alkaloid fraction of Rauvolfia ligustrina Roem. et Schult. in male mice

    Directory of Open Access Journals (Sweden)

    Lucindo J. Quintans-Júnior

    Full Text Available Rauvolfia ligustrina Roem et. Schult (Apocynaceae, commonly known as "paratudo" and "arrebenta-boi" is a small tree found in Brazilian Northeastern. Previous studies have demonstrated depressant and anticonvulsant properties of the ethanol extract of Rauvolfia ligustrina. The aim of the present study was the determination of the lethal dose 50% (LD50 and the effects of total alkaloid fraction (TAF of the aerial parts of R. ligustrina in animal models of convulsion. It was found that the acute toxicity of TAF was 127.8 (112.5-145.2 mg/kg (i.p. in mice. TAF (20 mg/kg, ip significantly increased (p < 0.05 the latencies of clonic seizures induced by pentylenetetrazol (PTZ and picrotoxin (PIC. However, TAF did not protect the animals in maximal electroshock (MES induced seizures. These results suggest that TAF of R. ligustrina possesses anticonvulsant properties.

  9. Dose fractionation in synchrotron radiation x-ray phase micro-tomography

    International Nuclear Information System (INIS)

    Frachon, Thibaut; Weber, Loriane; Hesse, Bernhard; Rit, Simon; Dong, Pei; Olivier, Cecile; Peyrin, Françoise; Langer, Max

    2015-01-01

    Phase sensitive x-ray imaging expands the applicability of standard attenuation based techniques by offering several orders of magnitude of increase in sensitivity. Due to the short wavelength, x-ray phase is not directly measurable, but has to be put in evidence by the use of phase contrast techniques. The phase can then be reconstructed from one or several phase contrast images. In this study, we consider synchrotron x-ray phase micro-computed tomography (μCT) based on free space propagation for heterogeneous and strongly absorbing objects. This technique generally relies on acquiring several scans of the sample at different detector distances. It is also generally believed that multi-distance phase μCT needs a higher dose input than single distance phase μCT. The purpose of this work is to study the impact of different means of dose fractionation on the reconstructed image quality. We define different acquistion schemes in multi-distance in-line phase μCT. Previously, the exposure time at each sample-to-detector distance was usually kept the same. Here, we let not only the number of distances vary but also the fraction of exposure time at each distance, the total exposure time being kept constant. Phase retrieval is performed with the mixed approach algorithm. The reconstructed μCT images are compared in terms of accuracy, precision and resolution. In addition, we also compare the result of dose fractionated multi distance phase μCT to single distance phase μCT using the same total radiation dose. In the multi-distance approach, we find that using different exposure times on each distance improves the image quality in the reconstructed image. Further, we show that, despite having the same total dose delivery, the multi distance imaging method gives better image quality than the single distance method, at the cost of an additional overhead from camera displacements and reference images. We show that by optimizing the acquistion parameters in terms of

  10. Total alkaloid content in various fractions of Tabernaemonata sphaerocarpa Bl. (Jembirit) leaves

    Science.gov (United States)

    Salamah, N.; Ningsih, D. S.

    2017-11-01

    Tabernaemontana sphaerocarpa Bl. (Jembirit) is one of the Apocynaceae family plants containing alkaloid compound. Traditionally, it is used as an anti-inflammatory medicine. It is found to have a new bisindole alkaloid compound that shows a potent cytotoxic activity in human cancer. This study aimed to know the total alkaloid content in some fractions of ethanolic extract of T. sphaerocarpa Bl. leaf powder was extracted by maceration method in 70% ethanol solvent. Then, the extract was fractionated in a separatory funnel using water, ethyl acetate, and hexane. The total alkaloid content in each fraction was analyzed with visible spectrophotometric methods based on the reaction with Bromocresol Green (BCG). The total alkaloids in water fraction and ethyl acetate fraction were (0.0312±0.0009)% and (0.0281±0.0014)%, respectively. Meanwhile, the total alkaloid content in hexane was not detected. The statistical analysis, performed in SPSS, resulted in a significant difference between the total alkaloids in water fraction and ethyl acetate fraction. The total alkaloid in water fraction of T. sphaerocarpa Bl. was higher than the one in ethyl acetate fraction.

  11. Statistical analysis of dose heterogeneity in circulating blood: Implications for sequential methods of total body irradiation

    International Nuclear Information System (INIS)

    Molloy, Janelle A.

    2010-01-01

    Purpose: Improvements in delivery techniques for total body irradiation (TBI) using Tomotherapy and intensity modulated radiation therapy have been proven feasible. Despite the promise of improved dose conformality, the application of these ''sequential'' techniques has been hampered by concerns over dose heterogeneity to circulating blood. The present study was conducted to provide quantitative evidence regarding the potential clinical impact of this heterogeneity. Methods: Blood perfusion was modeled analytically as possessing linear, sinusoidal motion in the craniocaudal dimension. The average perfusion period for human circulation was estimated to be approximately 78 s. Sequential treatment delivery was modeled as a Gaussian-shaped dose cloud with a 10 cm length that traversed a 183 cm patient length at a uniform speed. Total dose to circulating blood voxels was calculated via numerical integration and normalized to 2 Gy per fraction. Dose statistics and equivalent uniform dose (EUD) were calculated for relevant treatment times, radiobiological parameters, blood perfusion rates, and fractionation schemes. The model was then refined to account for random dispersion superimposed onto the underlying periodic blood flow. Finally, a fully stochastic model was developed using binomial and trinomial probability distributions. These models allowed for the analysis of nonlinear sequential treatment modalities and treatment designs that incorporate deliberate organ sparing. Results: The dose received by individual blood voxels exhibited asymmetric behavior that depended on the coherence among the blood velocity, circulation phase, and the spatiotemporal characteristics of the irradiation beam. Heterogeneity increased with the perfusion period and decreased with the treatment time. Notwithstanding, heterogeneity was less than ±10% for perfusion periods less than 150 s. The EUD was compromised for radiosensitive cells, long perfusion periods, and short treatment times

  12. Statistical analysis of dose heterogeneity in circulating blood: implications for sequential methods of total body irradiation.

    Science.gov (United States)

    Molloy, Janelle A

    2010-11-01

    Improvements in delivery techniques for total body irradiation (TBI) using Tomotherapy and intensity modulated radiation therapy have been proven feasible. Despite the promise of improved dose conformality, the application of these "sequential" techniques has been hampered by concerns over dose heterogeneity to circulating blood. The present study was conducted to provide quantitative evidence regarding the potential clinical impact of this heterogeneity. Blood perfusion was modeled analytically as possessing linear, sinusoidal motion in the craniocaudal dimension. The average perfusion period for human circulation was estimated to be approximately 78 s. Sequential treatment delivery was modeled as a Gaussian-shaped dose cloud with a 10 cm length that traversed a 183 cm patient length at a uniform speed. Total dose to circulating blood voxels was calculated via numerical integration and normalized to 2 Gy per fraction. Dose statistics and equivalent uniform dose (EUD) were calculated for relevant treatment times, radiobiological parameters, blood perfusion rates, and fractionation schemes. The model was then refined to account for random dispersion superimposed onto the underlying periodic blood flow. Finally, a fully stochastic model was developed using binomial and trinomial probability distributions. These models allowed for the analysis of nonlinear sequential treatment modalities and treatment designs that incorporate deliberate organ sparing. The dose received by individual blood voxels exhibited asymmetric behavior that depended on the coherence among the blood velocity, circulation phase, and the spatiotemporal characteristics of the irradiation beam. Heterogeneity increased with the perfusion period and decreased with the treatment time. Notwithstanding, heterogeneity was less than +/- 10% for perfusion periods less than 150 s. The EUD was compromised for radiosensitive cells, long perfusion periods, and short treatment times. However, the EUD was

  13. Impact of Fraction Size on Lung Radiation Toxicity: Hypofractionation may be Beneficial in Dose Escalation of Radiotherapy for Lung Cancers

    International Nuclear Information System (INIS)

    Jin Jinyue; Kong Fengming; Chetty, Indrin J.; Ajlouni, Munther; Ryu, Samuel; Ten Haken, Randall; Movsas, Benjamin

    2010-01-01

    Purpose: To assess how fraction size impacts lung radiation toxicity and therapeutic ratio in treatment of lung cancers. Methods and Materials: The relative damaged volume (RDV) of lung was used as the endpoint in the comparison of various fractionation schemes with the same normalized total dose (NTD) to the tumor. The RDV was computed from the biologically corrected lung dose-volume histogram (DVH), with an α/β ratio of 3 and 10 for lung and tumor, respectively. Two different (linear and S-shaped) local dose-effect models that incorporated the concept of a threshold dose effect with a single parameter D L50 (dose at 50% local dose effect) were used to convert the DVH into the RDV. The comparison was conducted using four representative DVHs at different NTD and D L50 values. Results: The RDV decreased with increasing dose/fraction when the NTD was larger than a critical dose (D CR ) and increased when the NTD was less than D CR . The D CR was 32-50 Gy and 58-87 Gy for a small tumor (11 cm 3 ) for the linear and S-shaped local dose-effect models, respectively, when D L50 was 20-30 Gy. The D CR was 66-97 Gy and 66-99 Gy, respectively, for a large tumor (266 cm 3 ). Hypofractionation was preferred for small tumors and higher NTDs, and conventional fractionation was better for large tumors and lower NTDs. Hypofractionation might be beneficial for intermediate-sized tumors when NTD = 80-90 Gy, especially if the D L50 is small (20 Gy). Conclusion: This computational study demonstrated that hypofractionated stereotactic body radiotherapy is a better regimen than conventional fractionation in lung cancer patients with small tumors and high doses, because it generates lower RDV when the tumor NTD is kept unchanged.

  14. Fraction of a dose absorbed estimation for structurally diverse low solubility compounds.

    Science.gov (United States)

    Sugano, Kiyohiko

    2011-02-28

    The purpose of the present study was to investigate the prediction accuracy of the fully mechanistic gastrointestinal unified theoretical (GUT) framework for in vivo oral absorption of low solubility drugs. Solubility in biorelevant media, molecular weight, logP(oct), pK(a), Caco-2 permeability, dose and particle size were used as the input parameters. To neglect the effect of the low stomach pH on dissolution of a drug, the fraction of a dose absorbed (Fa%) of undissociable and free acids were used. In addition, Fa% of free base drugs with the high pH stomach was also included to increase the number of model drugs. In total twenty nine structurally diverse compounds were used as the model drugs. Fa% data at several doses and particle sizes in humans and dogs were collated from the literature (total 110 Fa% data). In approximately 80% cases, the prediction error was within 2 fold, suggesting that the GUT framework has practical predictability for drug discovery, but not for drug development. The GUT framework appropriately captured the dose and particle size dependency of Fa% as the particle drifting effect was taken into account. It should be noted that the present validation results cannot be applied for salt form cases and other special formulations such as solid dispersions and emulsion formulations. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. An improved standard total dose test for CMOS space electronics

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Winokur, P.S.; Riewe, L.C.; Pease, R.L.

    1989-01-01

    The postirradiation response of hardened and commercial CMOS devices is investigated as a function of total dose, dose rate, and annealing time and temperature. Cobalt-60 irradiation at ≅ 200 rad(SiO 2 )/s followed by a 1-week 100 degrees C biased anneal and testing is shown to be an effective screen of hardened devices for space use. However, a similar screen and single-point test performed after Co-60 irradiation and elevated temperature anneal cannot be generally defined for commercial devices. In the absence of detailed knowledge about device and circuit radiation response, a two-point standard test is proposed to ensure space surviability of CMOS circuits: a Co-60 irradiation and test to screen against oxide-trapped charge related failures, and an additional rebound test to screen against interface-trap related failures. Testing implications for bipolar technologies are also discussed

  16. Total dose and dose rate models for bipolar transistors in circuit simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Phillip Montgomery; Wix, Steven D.

    2013-05-01

    The objective of this work is to develop a model for total dose effects in bipolar junction transistors for use in circuit simulation. The components of the model are an electrical model of device performance that includes the effects of trapped charge on device behavior, and a model that calculates the trapped charge densities in a specific device structure as a function of radiation dose and dose rate. Simulations based on this model are found to agree well with measurements on a number of devices for which data are available.

  17. Theoretical considerations for SRAM total-dose hardening

    International Nuclear Information System (INIS)

    Francis, P.; Flandre, D.; Colinge, J.P.

    1995-01-01

    The theoretical hardness against total dose of the six-transistor SRAM cell is investigated in detail. An explicit analytical expression of the maximum tolerable threshold voltage shift is derived for two cross-coupled inverters. A numerical method is used to explore the hardness of the read and write operations. Both N- and P-channel access transistors designs are considered and their respective advantages are compared. The study points out that the radiation hardness mainly relies on the technology. Results obtained with the very robust Gate-All-Around process are finally presented

  18. Fractionated total body irradiation; the gastrointestinal toxicity versus the conditioning effect for bone marrow transplantation with different fractionation schedules

    International Nuclear Information System (INIS)

    Walma, E.P.; Klapwijk, W.M.; Miller, A.M.

    1982-01-01

    In most cases, bone marrow transplantation is preceded by a conditioning regimen employing irradiation and/or cytotoxic drugs. The authors are searching for better fractionation schedules in order to optimize the conditioning regimen prior to transplantation of stem-cell-enriched bone marrow. They have determined damage to the gastrointestinal tract in dogs and mice after total body irradiation in mice and dogs following a number of fractionation schedules, and these results are presented. The schedules were chosen such as to minimize the interval between irradiation and the bone marrow transplantation and to maximize clinical feasibility. (Auth./C.F.)

  19. Fractionation and characterization of particles simulating wear of total joint replacement (TJR) following ASTM standards.

    Science.gov (United States)

    Saha, Subrata; Musib, Mrinal

    2011-01-01

    Reactions of bone cells to orthopedic wear debris produced by the articulating motion of total joint replacements (TJRs) are largely responsible for the long-term failure of such replacements. Metal and polyethylene (PE) wear particles isolated from fluids from total joint simulators, as well as particles that are fabricated by other methods, are widely used to study such in vitro cellular response. Prior investigations have revealed that cellular response to wear debris depends on the size, shape, and dose of the particles. Hence, to have a better understanding of the wear-mediated osteolytic process it is important that these particles are well characterized and clinically relevant, both qualitatively, and quantitatively. In this study we have fractionated both ultra-high molecular weight polyethylene (UHMWPE) and Ti particles, into micron (1.0-10.0 μm), submicron (0.2-1.0 μm), and nanoparticle (0.01-0.2 μm) fractions, and characterized them based on the following size-shape descriptors as put forth in ASTM F1877: i) equivalent circle diameter (ECD), ii) aspect ratio (AR), iii) elongation (E), iv) roundness (R), and v) form factor (FF). The mean (± SD) ECDs (in μm) for micron, submicron, and nanoparticles of UHMWPE were 1.652 ± 0.553, 0.270 ± 0.180, and 0.061 ± 0.035, respectively, and for Ti were 1.894 ± 0.667, 0.278 ± 0.180, and 0.055 ± 0.029, respectively. The values for other descriptors were similar (no statistically significant difference). The nanofraction particles were found to be more sphere-like (higher R and FF values, and lower E and AR values) as compared to larger particles. Future experiments will involve use of these well characterized particles for in vitro studies.

  20. Superfractionation as a potential hypoxic cell radiosensitizer: prediction of an optimum dose per fraction

    International Nuclear Information System (INIS)

    Dasu, Alexandru; Denekamp, Juliana

    1999-01-01

    Purpose: A dose 'window of opportunity' has been identified in an earlier modeling study if the inducible repair variant of the LQ model is adopted instead of the pure LQ model, and if all survival curve parameters are equally modified by the presence or absence of oxygen. In this paper we have extended the calculations to consider survival curve parameters from 15 sets of data obtained for cells tested at low doses using clonogenic assays. Methods and Materials: A simple computer model has been used to simulate the response of each cell line to various doses per fraction in multifraction schedules, with oxic and hypoxic cells receiving the same fractional dose. We have then used pairs of simulated survival curves to estimate the effective hypoxic protection (OER') as a function of the dose per fraction. Results: The resistance of hypoxic cells is reduced by using smaller doses per fraction than 2 Gy in all these fractionated clinical simulations, whether using a simple LQ model, or the more complex LQ/IR model. If there is no inducible repair, the optimum dose is infinitely low. If there is inducible repair, there is an optimum dose per fraction at which hypoxic protection is minimized. This is usually around 0.5 Gy. It depends on the dose needed to induce repair being higher in hypoxia than in oxygen. The OER' may even go below unity, i.e. hypoxic cells may be more sensitive than oxic cells. Conclusions: If oxic and hypoxic cells are repeatedly exposed to doses of the same magnitude, as occurs in clinical radiotherapy, the observed hypoxic protection varies with the fractional dose. The OER' is predicted to diminish at lower doses in all cell lines. The loss of hypoxic resistance with superfractionation is predicted to be proportional to the capacity of the cells to induce repair, i.e. their intrinsic radioresistance at a dose of 2 Gy

  1. Total effective dose equivalent associated with fixed uranium surface contamination

    International Nuclear Information System (INIS)

    Bogard, J.S.; Hamm, R.N.; Ashley, J.C.; Turner, J.E.; England, C.A.; Swenson, D.E.; Brown, K.S.

    1997-04-01

    This report provides the technical basis for establishing a uranium fixed-contamination action level, a fixed uranium surface contamination level exceeding the total radioactivity values of Appendix D of Title 10, Code of Federal Regulations, part 835 (10CFR835), but below which the monitoring, posting, and control requirements for Radiological Areas are not required for the area of the contamination. An area of fixed uranium contamination between 1,000 dpm/100 cm 2 and that level corresponding to an annual total effective dose equivalent (TEDE) of 100 mrem requires only routine monitoring, posting to alert personnel of the contamination, and administrative control. The more extensive requirements for monitoring, posting, and control designated by 10CFR835 for Radiological Areas do not have to be applied for these intermediate fixed-contamination levels

  2. Single and 30 fraction tumor control doses correlate in xenografted tumor models: implications for predictive assays

    International Nuclear Information System (INIS)

    Gerweck, Leo E.; Dubois, Willum; Baumann, Michael; Suit, Herman D.

    1995-01-01

    Purpose/Objective: In a previous publication we reported that laboratory assays of tumor clonogen number, in combination with intrinsic radiosensitivity measured in-vitro, accurately predicted the rank-order of single fraction 50% tumor control doses, in six rodent and xenografted human tumors. In these studies, tumor hypoxia influenced the absolute value of the tumor control doses across tumor types, but not their rank-order. In the present study we hypothesize that determinants of the single fraction tumor control dose, may also strongly influence the fractionaled tumor control doses, and that knowledge of tumor clonogen number and their sensitivity to fractionated irradiation, may be useful for predicting the relative sensitivity of tumors treated by conventional fractionated irradiation. Methods/Materials: Five tumors of human origin were used for these studies. Special care was taken to ensure that all tumor control dose assays were performed over the same time frame, i.e., in-vitro cells of a similar passage were used to initiate tumor sources which were expanded and used in the 3rd or 4th generation. Thirty fraction tumor control doses were performed in air breathing mice, under normal blood flow conditions (two fractions/day). The results of these studies have been previously published. For studies under uniformly (clamp) hypoxic conditions, tumors arising from the same transplantation were randomized into single or fractionated dose protocols. For estimation of the fractionated TCD50 under hypoxic conditions, tumors were exposed to six 5.4 Gy fractions (∼ 2 Gy equivalent under air), followed by graded 'top-up' dose irradiation for determination of the TCD50; the time interval between doses was 6-9 hours. The single dose equivalent of the six 5.4 Gy doses was used to calculate an extrapolated 30 fraction hypoxic TCD50. Results: Fractionation substantially increased the dose required for tumor control in 4 of the 5 tumors investigated. For these 4 tumors

  3. A model to accumulate fractionated dose in a deforming organ

    International Nuclear Information System (INIS)

    Yan Di; Jaffray, D.A.; Wong, J.W.

    1999-01-01

    Purpose: Measurements of internal organ motion have demonstrated that daily organ deformation exists throughout the course of radiation treatment. However, a method of constructing the resultant dose delivered to the organ volume remains a difficult challenge. In this study, a model to quantify internal organ motion and a method to construct a cumulative dose in a deforming organ are introduced. Methods and Materials: A biomechanical model of an elastic body is used to quantify patient organ motion in the process of radiation therapy. Intertreatment displacements of volume elements in an organ of interest is calculated by applying an finite element method with boundary conditions, obtained from multiple daily computed tomography (CT) measurements. Therefore, by incorporating also the measurements of daily setup error, daily dose delivered to a deforming organ can be accumulated by tracking the position of volume elements in the organ. Furthermore, distribution of patient-specific organ motion is also predicted during the early phase of treatment delivery using the daily measurements, and the cumulative dose distribution in the organ can then be estimated. This dose distribution will be updated whenever a new measurement becomes available, and used to reoptimize the ongoing treatment. Results: An integrated process to accumulate dosage in a daily deforming organ was implemented. In this process, intertreatment organ motion and setup error were systematically quantified, and incorporated in the calculation of the cumulative dose. An example of the rectal wall motion in a prostate treatment was applied to test the model. The displacements of volume elements in the rectal wall, as well as the resultant doses, were calculated. Conclusion: This study is intended to provide a systematic framework to incorporate daily patient-specific organ motion and setup error in the reconstruction of the cumulative dose distribution in an organ of interest. The realistic dose

  4. A simple method to calculate the influence of dose inhomogeneity and fractionation in normal tissue complication probability evaluation

    International Nuclear Information System (INIS)

    Begnozzi, L.; Gentile, F.P.; Di Nallo, A.M.; Chiatti, L.; Zicari, C.; Consorti, R.; Benassi, M.

    1994-01-01

    Since volumetric dose distributions are available with 3-dimensional radiotherapy treatment planning they can be used in statistical evaluation of response to radiation. This report presents a method to calculate the influence of dose inhomogeneity and fractionation in normal tissue complication probability evaluation. The mathematical expression for the calculation of normal tissue complication probability has been derived combining the Lyman model with the histogram reduction method of Kutcher et al. and using the normalized total dose (NTD) instead of the total dose. The fitting of published tolerance data, in case of homogeneous or partial brain irradiation, has been considered. For the same total or partial volume homogeneous irradiation of the brain, curves of normal tissue complication probability have been calculated with fraction size of 1.5 Gy and of 3 Gy instead of 2 Gy, to show the influence of fraction size. The influence of dose distribution inhomogeneity and α/β value has also been simulated: Considering α/β=1.6 Gy or α/β=4.1 Gy for kidney clinical nephritis, the calculated curves of normal tissue complication probability are shown. Combining NTD calculations and histogram reduction techniques, normal tissue complication probability can be estimated taking into account the most relevant contributing factors, including the volume effect. (orig.) [de

  5. High dose per fraction dosimetry of small fields with Gafchromic EBT2 film

    International Nuclear Information System (INIS)

    Hardcastle, Nicholas; Basavatia, Amar; Bayliss, Adam; Tome, Wolfgang A.

    2011-01-01

    Purpose: Small field dosimetry is prone to uncertainties due to the lack of electronic equilibrium and the use of the correct detector size relative to the field size measured. It also exhibits higher sensitivity to setup errors as well as large variation in output with field size and shape. Radiochromic film is an attractive method for reference dosimetry in small fields due to its ability to provide 2D dose measurements while having minimal impact on the dose distribution. Gafchromic EBT2 has a dose range of up to 40 Gy; therefore, it could potentially be useful for high dose reference dosimetry with high spatial resolution. This is a requirement in stereotactic radiosurgery deliveries, which deliver high doses per fraction to small targets. Methods: Targets of 4 mm and 12 mm diameters were treated to a minimum peripheral dose of 21 Gy prescribed to 80% of the maximum dose in one fraction. Target doses were measured with EBT2 film (both targets) and an ion chamber (12 mm target only). Measured doses were compared with planned dose distributions using profiles through the target and minimum peripheral dose coverage. Results: The measured target doses and isodose coverage agreed with the planned dose within ±1 standard deviation of three measurements, which were 2.13% and 2.5% for the 4 mm and 12 mm targets, respectively. Conclusions: EBT2 film is a feasible dosimeter for high dose per fraction reference 2D dosimetry.

  6. Esophageal Toxicity From High-Dose, Single-Fraction Paraspinal Stereotactic Radiosurgery

    International Nuclear Information System (INIS)

    Cox, Brett W.; Jackson, Andrew; Hunt, Margie; Bilsky, Mark; Yamada, Yoshiya

    2012-01-01

    Purpose: To report the esophageal toxicity from single-fraction paraspinal stereotactic radiosurgery (SRS) and identify dosimetric and clinical risk factors for toxicity. Methods and Materials: A total of 204 spinal metastases abutting the esophagus (182 patients) were treated with high-dose single-fraction SRS during 2003-2010. Toxicity was scored using the National Cancer Institute Common Toxicity Criteria for Adverse Events, version 4.0. Dose-volume histograms were combined to generate a comprehensive atlas of complication incidence that identifies risk factors for toxicity. Correlation of dose-volume factors with esophageal toxicity was assessed using Fisher’s exact test and logistic regression. Clinical factors were correlated with toxicity. Results: The median dose to the planning treatment volume was 24 Gy. Median follow-up was 12 months (range, 3-81). There were 31 (15%) acute and 24 (12%) late esophageal toxicities. The rate of grade ≥3 acute or late toxicity was 6.8% (14 patients). Fisher’s exact test resulted in significant median splits for grade ≥3 toxicity at V12 = 3.78 cm 3 (relative risk [RR] 3.7, P=.05), V15 = 1.87 cm 3 (RR 13, P=.0013), V20 = 0.11 cm 3 (RR 6, P=0.01), and V22 = 0.0 cm 3 (RR 13, P=.0013). The median split for D2.5 cm 3 (14.02 Gy) was also a significant predictor of toxicity (RR 6; P=.01). A highly significant logistic regression model was generated on the basis of D2.5 cm 3 . One hundred percent (n = 7) of grade ≥4 toxicities were associated with radiation recall reactions after doxorubicin or gemcitabine chemotherapy or iatrogenic manipulation of the irradiated esophagus. Conclusions: High-dose, single-fraction paraspinal SRS has a low rate of grade ≥3 esophageal toxicity. Severe esophageal toxicity is minimized with careful attention to esophageal doses during treatment planning. Iatrogenic manipulation of the irradiated esophagus and systemic agents classically associated with radiation recall reactions are

  7. Fractional-Order Total Variation Image Restoration Based on Primal-Dual Algorithm

    OpenAIRE

    Chen, Dali; Chen, YangQuan; Xue, Dingyu

    2013-01-01

    This paper proposes a fractional-order total variation image denoising algorithm based on the primal-dual method, which provides a much more elegant and effective way of treating problems of the algorithm implementation, ill-posed inverse, convergence rate, and blocky effect. The fractional-order total variation model is introduced by generalizing the first-order model, and the corresponding saddle-point and dual formulation are constructed in theory. In order to guarantee $O(1/{N}^{2})$ conv...

  8. Radical radiotherapy for invasive bladder cancer: What dose and fractionation schedule to choose?

    International Nuclear Information System (INIS)

    Pos, Floris J.; Hart, Guus; Schneider, Christoph; Sminia, Peter

    2006-01-01

    Purpose: To establish the α/β ratio of bladder cancer from different radiotherapy schedules reported in the literature and provide guidelines for the design of new treatment schemes. Methods and Materials: Ten external beam radiotherapy (EBRT) and five brachytherapy schedules were selected. The biologically effective dose (BED) of each schedule was calculated. Logistic modeling was used to describe the relationship between 3-year local control (LC3y) and BED. Results: The estimated α/β ratio was 13 Gy (95% confidence interval [CI], 2.5-69 Gy) for EBRT and 24 Gy (95% CI, 1.3-460 Gy) for EBRT and brachytherapy combined. There is evidence for an overall dose-response relationship. After an increase in total dose of 10 Gy, the odds of LC3y increase by a factor of 1.44 (95% CI, 1.23-1.70) for EBRT and 1.47 (95% CI, 1.25-1.72) for the data sets of EBRT and brachytherapy combined. Conclusion: With the clinical data currently available, a reliable estimation of the α/β ratio for bladder cancer is not feasible. It seems reasonable to use a conventional α/β ratio of 10-15 Gy. Dose escalation could significantly increase local control. There is no evidence to support short overall treatment times or large fraction sizes in radiotherapy for bladder cancer

  9. Total Risk Management for Low Dose Radiation Exposures

    International Nuclear Information System (INIS)

    Simic, Z.; Mikulicic, V.; Sterc, D.

    2012-01-01

    health. This view is supported with numerous evidences, and explained with beneficial effects from the increased activity of immune system activated with small radiation exposures. Finally, theory in between is that small doses are less than linearly proportionally harmful and that they are presenting a much smaller risks than according to the LNT. This view is derived from the use of different evidences. Difficulties to find one single theory about effects of small radiation doses are related to existence of huge variability and uncertainty in the evidence data. This is very hard experimental and theoretical problem. It will require lots of additional research to reduce these uncertainties and find final theory. This might be too late for the number of people affected in different ways with current single most conservative LNT approach. The problem with the conservative LNT regulatory approach is resulting in enormous additional costs of nuclear energy and medical applications. Which is reasonable and acceptable during the regular operation when source is high and concentrated. But, this becomes unreasonable huge economic burden after accidents and for cleanups with nuclear facilities. Similar problem arises with restriction of medical examinations and treatments based on over conservative risk estimate. Special circumstances are with evacuated people from contaminated areas where they are on the one side saved from small radiation exposures, and on the other side exposed to years of life away from their home and with numerous direct and indirect additional risks (i.e., stress, social problems, etc.). It seems reasonable that some alternative (total) risk management approach might be much more suitable for this situation. Evacuation of people from contaminated area with small doses sources should not be done when that induces larger risks from even what is expected from radiation based on LNT. Similar total risk management could be also applied for with medical

  10. Immunogenicity to poliovirus type 2 following two doses of fractional intradermal inactivated poliovirus vaccine: A novel dose sparing immunization schedule.

    Science.gov (United States)

    Anand, Abhijeet; Molodecky, Natalie A; Pallansch, Mark A; Sutter, Roland W

    2017-05-19

    The polio eradication endgame strategic plan calls for the sequential removal of Sabin poliovirus serotypes from the trivalent oral poliovirus vaccine (tOPV), starting with type 2, and the introduction of ≥1 dose of inactivated poliovirus vaccine (IPV), to maintain an immunity base against poliovirus type 2. The global removal of oral poliovirus type 2 was successfully implemented in May 2016. However, IPV supply constraints has prevented introduction in 21 countries and led to complete stock-out in >20 countries. We conducted a literature review and contacted corresponding authors of recent studies with fractional-dose IPV (fIPV), one-fifth of intramuscular dose administered intradermally, to conduct additional type 2 immunogenicity analyses of two fIPV doses compared with one full-dose IPV. Four studies were identified that assessed immunogenicity of two fIPV doses compared to one full-dose IPV. Two fractional doses are more immunogenic than 1 full-dose, with type 2 seroconversion rates improving between absolute 19-42% (median: 37%, pvaccine compared to one full-dose IPV. In response to the current IPV shortage, a schedule of two fIPV doses at ages 6 and 14weekshas been endorsed by technical oversight committees and has been introduced in some affected countries. Copyright © 2017. Published by Elsevier Ltd.

  11. Low or High Fractionation Dose {beta}-Radiotherapy for Pterygium? A Randomized Clinical Trial

    Energy Technology Data Exchange (ETDEWEB)

    Viani, Gustavo Arruda, E-mail: gusviani@gmail.com [Department of Radiation Oncology, Marilia Medicine School, Sao Paulo, SP (Brazil); De Fendi, Ligia Issa; Fonseca, Ellen Carrara [Department of Ophthalmology, Marilia Medicine School, Sao Paulo, SP (Brazil); Stefano, Eduardo Jose [Department of Radiation Oncology, Marilia Medicine School, Sao Paulo, SP (Brazil)

    2012-02-01

    Purpose: Postoperative adjuvant treatment using {beta}-radiotherapy (RT) is a proven technique for reducing the recurrence of pterygium. A randomized trial was conducted to determine whether a low fractionation dose of 2 Gy within 10 fractions would provide local control similar to that after a high fractionation dose of 5 Gy within 7 fractions for surgically resected pterygium. Methods: A randomized trial was conducted in 200 patients (216 pterygia) between February 2006 and July 2007. Only patients with fresh pterygium resected using a bare sclera method and given RT within 3 days were included. Postoperative RT was delivered using a strontium-90 eye applicator. The pterygia were randomly treated using either 5 Gy within 7 fractions (Group 1) or 2 Gy within 10 fractions (Group 2). The local control rate was calculated from the date of surgery. Results: Of the 216 pterygia included, 112 were allocated to Group 1 and 104 to Group 2. The 3-year local control rate for Groups 1 and 2 was 93.8% and 92.3%, respectively (p = .616). A statistically significant difference for cosmetic effect (p = .034), photophobia (p = .02), irritation (p = .001), and scleromalacia (p = .017) was noted in favor of Group 2. Conclusions: No better local control rate for postoperative pterygium was obtained using high-dose fractionation vs. low-dose fractionation. However, a low-dose fractionation schedule produced better cosmetic effects and resulted in fewer symptoms than high-dose fractionation. Moreover, pterygia can be safely treated in terms of local recurrence using RT schedules with a biologic effective dose of 24-52.5 Gy{sub 10.}.

  12. Response of rat spinal cord to very small doses per fraction: lack of enhanced radiosensitivity

    International Nuclear Information System (INIS)

    Shun, Wong C.; Yong, Hao; Hill, Richard P.

    1995-01-01

    Our previous work with rat spinal cord demonstrated that the linear quadratic (LQ) model based on data for large fraction sizes ((α(β)) of 2.4 Gy) failed to predict isoeffective doses between 1 and 2 Gy per fraction, and under-estimated the sparing effect of small doses per fraction given once daily. In contrast, data from mouse skin and kidney, and recent in vitro results revealed a paradoxical increase in radiosensitivity at below 1 Gy per fraction. To assess whether enhanced radiosensitivity is present in the spinal cord below 1 Gy per fraction, the rat spinal cord (C2-T2) was irradiated initially with three daily doses of 10.25 Gy (top-up doses representing 90% of tolerance), followed by graded single doses or fractionated doses in 1.5, 1.0, 0.8, 0.6 or 0.4 Gy fractions given once daily. To limit the overall treatment time to ≤ 8 weeks, a small number of the 0.6- and 0.4-Gy fractions were given twice daily with an interfraction interval of 16 h. The end-point was forelimb paralysis secondary to white matter necrosis, confirmed histologically. The ED 50 values, excluding the top-up doses, were 5.8, 10.6, 14.8, 15.2, 15.9 and 19.1 Gy for a single dose and doses in 1.5-, 1.0-, 0.8-, 0.6- and 0.4-Gy fractions, respectively. The data gave an (α(β)) of 2.1 Gy (95% CI, 1.4, 2.7 Gy). Pooling the data separately, the (α(β)) value was 2.3 Gy (95% CI, 0.82, 3.7 Gy) for fraction sizes ≥ 1 Gy, and 1.2 Gy (95% CI, 0.16, 2.3 Gy) for the 0.8-, 0.6- and 0.4-Gy experiments. These results in which top-up doses were given initially are consistent with a large sparing effect of very small fraction sizes in rat spinal cord provided sufficient time is allowed for repair of sublethal damage between fractions, and provide no evidence for a paradoxical increase in radiosensitivity in the rat spinal cord below 1 Gy down to 0.4 Gy per fraction

  13. Analytical models for total dose ionization effects in MOS devices.

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Phillip Montgomery; Bogdan, Carolyn W.

    2008-08-01

    MOS devices are susceptible to damage by ionizing radiation due to charge buildup in gate, field and SOI buried oxides. Under positive bias holes created in the gate oxide will transport to the Si / SiO{sub 2} interface creating oxide-trapped charge. As a result of hole transport and trapping, hydrogen is liberated in the oxide which can create interface-trapped charge. The trapped charge will affect the threshold voltage and degrade the channel mobility. Neutralization of oxidetrapped charge by electron tunneling from the silicon and by thermal emission can take place over long periods of time. Neutralization of interface-trapped charge is not observed at room temperature. Analytical models are developed that account for the principal effects of total dose in MOS devices under different gate bias. The intent is to obtain closed-form solutions that can be used in circuit simulation. Expressions are derived for the aging effects of very low dose rate radiation over long time periods.

  14. Total Dose Effects on Bipolar Integrated Circuits at Low Temperature

    Science.gov (United States)

    Johnston, A. H.; Swimm, R. T.; Thorbourn, D. O.

    2012-01-01

    Total dose damage in bipolar integrated circuits is investigated at low temperature, along with the temperature dependence of the electrical parameters of internal transistors. Bandgap narrowing causes the gain of npn transistors to decrease far more at low temperature compared to pnp transistors, due to the large difference in emitter doping concentration. When irradiations are done at temperatures of -140 deg C, no damage occurs until devices are warmed to temperatures above -50 deg C. After warm-up, subsequent cooling shows that damage is then present at low temperature. This can be explained by the very strong temperature dependence of dispersive transport in the continuous-time-random-walk model for hole transport. For linear integrated circuits, low temperature operation is affected by the strong temperature dependence of npn transistors along with the higher sensitivity of lateral and substrate pnp transistors to radiation damage.

  15. Dose escalation by hypo fractionation in localized prostate cancer - a large single institution experience

    International Nuclear Information System (INIS)

    Mahadevan, A.; Klein, E.; Kupelian, P.

    2003-01-01

    To report the outcomes of high dose radiation therapy using Intensity Modulated Radiation Therapy (IMRT) with hypo fractionation in localized prostate cancer at the Cleveland Clinic Foundation. A total of 278 patients with localized prostate cancer were treated with IMRT between 1998 and 2001. All cases had available pretreatment PSA (iPSA) and biopsy Gleason scores (bGS), no nodal metastasis, a minimum 2 year follow-up, and >5 follow-up PSA levels. The frequency by T-stage was: T1-T2A in 86%, T2B-T2C in 9%, and T3 in 5%. The median iPSA was 8.35. The frequency by bGS was: =7 in 45%. The age range for the patients was from 48 to 85 years (median 68 years). The median follow-up was 33 months (range: 24-49 months). The median doses delivered were 83Gy (delivered at 2.5Gy per fraction to 70 Gy; this being equivalent to 83 Gy at standard fractionation of 1.8 Gy using an alpha/beta of 2). The ASTRO definition for biochemical failure was used. Toxicity was assessed using Radiation Therapy Oncology Group (RTOG) criteria. The 3-year biochemical relapse free survival (bRFS) for the entire cohort at three years was 91%. Any (grade 1 or higher) acute genito-urinary (GU) side effects were seen in 79% of patients. Grade 2 or higher acute GU toxicity was seen in 18% of patients. Any (grade 1 or higher) acute gastro-intestinal (GI) side effects were seen in 65% of patients. Grade 2 or higher acute GI toxicity was seen in 11% of patients. Any (grade 1 or higher) late GU side effects were seen in 3% of patients. Grade 2 or higher late GU toxicity was seen in 1.5% of patients. Any (grade 1 or higher) late GI side effects were seen in 13% of patients. Grade 2 or higher late GI toxicity was seen in 5% of patients. Higher doses of radiation delivered by IMRT resulted in excellent bRFS outcomes in patients with localized prostate cancer receiving external beam radiation therapy. IMRT can be effectively used to safely increase dose delivery without compromising on quality of life

  16. Justification for inter-fraction correction of catheter movement in fractionated high dose-rate brachytherapy treatment of prostate cancer

    International Nuclear Information System (INIS)

    Simnor, Tania; Li, Sonia; Lowe, Gerry; Ostler, Peter; Bryant, Linda; Chapman, Caroline; Inchley, Dave; Hoskin, Peter J.

    2009-01-01

    Background and purpose: Fractionated high dose-rate (HDR) brachytherapy in the treatment of prostate cancer relies on reproducible catheter positions for each fraction to ensure adequate tumour coverage while minimising dose to normal tissues. Peri-prostatic oedema may cause caudal displacement of the catheters relative to the prostate gland between fractions. This can be corrected for by changing source dwell positions or by physical re-advancement of catheters before treatment. Materials and methods: Data for 20 consecutive monotherapy patients receiving three HDR fractions of 10.5 Gy per fraction over 2 days were analysed retrospectively. Pre-treatment CT scans were used to assess the effect of catheter movement between fractions on implant quality, with and without movement correction. Implant quality was evaluated using dosimetric parameters. Results: Compared to the first fraction (f1) the mean inter-fraction caudal movement relative to the prostate base was 7.9 mm (f2) (range 0-21 mm) and 3.9 mm (f3) (range 0-25.5 mm). PTV D90% was reduced without movement correction by a mean of 27.8% (f2) and 32.3% (f3), compared with 5.3% and 5.1%, respectively, with catheter movement correction. Dose to 2 cc of the rectum increased by a mean of 0.69 (f2) and 0.76 Gy (f3) compared with an increase of 0.03 and 0.04 Gy, respectively, with correction. The urethra V12 also increased by a mean of 0.36 (f2) and 0.39 Gy (f3) compared with 0.06 and 0.16 Gy, respectively, with correction. Conclusions: Inter-fraction correction for catheter movement using pre-treatment imaging is critical to maintain the quality of an implant. Without movement correction there is significant risk of tumour under-dosage and normal tissue over-dosage. The findings of this study justify additional imaging between fractions in order to carry out correction.

  17. Not traditional regimes of radiotherapeutic dose fractionation as modifier of radiotherapy for carcinoma of lungs

    International Nuclear Information System (INIS)

    Artemova, N.A.

    2008-01-01

    The efficiency of applying various of radiotherapeutic dose fractionation was analyzed. The results of the own studies performed at the Scientific and Research Institute of Oncology and Medical Radiology for elaborating not traditional regimes of radiotherapeutic dose fractionation (a dynamic fractionation applying enlarged regimes at the first stage and the classic ones at the second stage) were presented. Appliance of the modified radiotherapy for the epidermoid carcinoma of the lungs allowed to increase the objective response from 45,3+-3% to 80+-5% the tumor disappearing completely in 40+-6% of patients as compared with 10+-2%. Appliance of the intensive not traditional variant of the radiotherapy dynamic fractionation in case of a small cell carcinoma of the lungs resulted in the therapy duration reduction from 6 to 4 weeks. Thus the not traditional dose fractionation might become a mechanism for the improving the radiotherapy of persons suffering from the carcinoma of the lungs. (authors)

  18. System simulation on fractionation radiation doses and radioisotope handling in Nuclear medicine

    International Nuclear Information System (INIS)

    Dytz, Aline Guerra; Dullius, Marcos Alexandre; Gomes, Camila e Silva

    2008-01-01

    This paper describes the practical and theoretical learning of students from Medical Physics course at the Fundacao Universidade Federal do Rio Grande (FURG) on fractionation radiation doses, radioisotope handling and elution of molybdenum generators (Mo-99) / technetium (Tc -99m)

  19. ANALYSIS OF RESPIRATORY DESPOSITION DOSE OF INHALED AMBIENT AEROSOLS FOR DIFFERENT SIZE FRACTIONS

    Science.gov (United States)

    ANALYSIS OF RESPIRATORY DEPOSITION DOSE OF INHALED AMBIENT AEROSOLS FOR DIFFERENT SIZE FRACTIONS. Chong S. Kim, SC. Hu**, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711; **IIT Research Institute, Chicago, IL; *S...

  20. Marrow transplantation for leukemia following fractionated total body irradiation. A comparative trial of methotrexate and cyclosporine

    International Nuclear Information System (INIS)

    Irle, C.; Deeg, H.J.; Buckner, C.D.; Swedish Hospital Medical Center, Seattle, WA; Veterans Administration Hospital, Seattle, WA; Washington Univ., Seattle

    1985-01-01

    Fifty-six patients, 30-47 yr of age, with leukemia in relapse received allogeneic marrow transplants from HLA-identical siblings. All patients were treated with cyclophosphamide (120 mg/kg) and 7 daily fractions of 2.25 Gy of total body irradiation (TBI) for seven consecutive days. Nine patients (16%) are currently alive, free of disease, 324-845 days from transplantation. Actuarial relapse and survival rates at 2 yr were 56% and 9.5% respectively. These data were not remarkably different from those in previous studies using 10 Gy of TBI administered as a single dose. Thirty patients were randomized to receive methotrexate (MTX) and 26 to receive cyclosporine (CSP) as postgrafting prophylaxis for acute graft-versus-host disease (GVHD). Probability of developing significant acute GVHD by day 100 post-transplant was 71% for patients in the MTX group and 45% for patients in the CSP group (p<0.05). Probability of relapse was 37% for patients in the MTX group and 70% for patients in the CSP group (p<0.05). Transplant-related deaths were more frequent in the MTX group and leukemic deaths more frequent in the CSP group although this may have been related to an uneven distribution of high-risk patients. Long term disease-free survival was comparable. (author)

  1. Limitations of a convolution method for modeling geometric uncertainties in radiation therapy: the radiobiological dose-per-fraction effect

    International Nuclear Information System (INIS)

    Song, William; Battista, Jerry; Van Dyk, Jake

    2004-01-01

    The convolution method can be used to model the effect of random geometric uncertainties into planned dose distributions used in radiation treatment planning. This is effectively done by linearly adding infinitesimally small doses, each with a particular geometric offset, over an assumed infinite number of fractions. However, this process inherently ignores the radiobiological dose-per-fraction effect since only the summed physical dose distribution is generated. The resultant potential error on predicted radiobiological outcome [quantified in this work with tumor control probability (TCP), equivalent uniform dose (EUD), normal tissue complication probability (NTCP), and generalized equivalent uniform dose (gEUD)] has yet to be thoroughly quantified. In this work, the results of a Monte Carlo simulation of geometric displacements are compared to those of the convolution method for random geometric uncertainties of 0, 1, 2, 3, 4, and 5 mm (standard deviation). The α/β CTV ratios of 0.8, 1.5, 3, 5, and 10 Gy are used to represent the range of radiation responses for different tumors, whereas a single α/β OAR ratio of 3 Gy is used to represent all the organs at risk (OAR). The analysis is performed on a four-field prostate treatment plan of 18 MV x rays. The fraction numbers are varied from 1-50, with isoeffective adjustments of the corresponding dose-per-fractions to maintain a constant tumor control, using the linear-quadratic cell survival model. The average differences in TCP and EUD of the target, and in NTCP and gEUD of the OAR calculated from the convolution and Monte Carlo methods reduced asymptotically as the total fraction number increased, with the differences reaching negligible levels beyond the treatment fraction number of ≥20. The convolution method generally overestimates the radiobiological indices, as compared to the Monte Carlo method, for the target volume, and underestimates those for the OAR. These effects are interconnected and attributed

  2. 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.

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  4. Human Milk MicroRNA and Total RNA Differ Depending on Milk Fractionation.

    Science.gov (United States)

    Alsaweed, Mohammed; Hepworth, Anna R; Lefèvre, Christophe; Hartmann, Peter E; Geddes, Donna T; Hassiotou, Foteini

    2015-10-01

    MicroRNA have been recently discovered in human milk signifying potentially important functions for both the lactating breast and the infant. Whilst human milk microRNA have started to be explored, little data exist on the evaluation of sample processing, and analysis to ensure that a full spectrum of microRNA can be obtained. Human milk comprises three main fractions: cells, skim milk, and lipids. Typically, the skim milk fraction has been measured in isolation despite evidence that the lipid fraction may contain more microRNA. This study aimed to standardize isolation of microRNA and total RNA from all three fractions of human milk to determine the most appropriate sampling and analysis procedure for future studies. Three different methods from eight commercially available kits were tested for their efficacy in extracting total RNA and microRNA from the lipid, skim, and cell fractions of human milk. Each fraction yielded different concentrations of RNA and microRNA, with the highest quantities found in the cell and lipid fractions, and the lowest in skim milk. The column-based phenol-free method was the most efficient extraction method for all three milk fractions. Two microRNAs were expressed and validated in the three milk fractions by qPCR using the three recommended extraction kits for each fraction. High expression levels were identified in the skim and lipid milk factions for these microRNAs. These results suggest that careful consideration of both the human milk sample preparation and extraction protocols should be made prior to embarking upon research in this area. © 2015 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

  5. Fractional dosing of yellow fever vaccine to extend supply: a modelling study.

    Science.gov (United States)

    Wu, Joseph T; Peak, Corey M; Leung, Gabriel M; Lipsitch, Marc

    2016-12-10

    The ongoing yellow fever epidemic in Angola strains the global vaccine supply, prompting WHO to adopt dose sparing for its vaccination campaign in Kinshasa, Democratic Republic of the Congo, in July-August, 2016. Although a 5-fold fractional-dose vaccine is similar to standard-dose vaccine in safety and immunogenicity, efficacy is untested. There is an urgent need to ensure the robustness of fractional-dose vaccination by elucidation of the conditions under which dose fractionation would reduce transmission. We estimate the effective reproductive number for yellow fever in Angola using disease natural history and case report data. With simple mathematical models of yellow fever transmission, we calculate the infection attack rate (the proportion of population infected over the course of an epidemic) with various levels of transmissibility and 5-fold fractional-dose vaccine efficacy for two vaccination scenarios, ie, random vaccination in a hypothetical population that is completely susceptible, and the Kinshasa vaccination campaign in July-August, 2016, with different age cutoff for fractional-dose vaccines. We estimate the effective reproductive number early in the Angola outbreak was between 5·2 and 7·1. If vaccine action is all-or-nothing (ie, a proportion of vaccine recipients receive complete protection [VE] and the remainder receive no protection), n-fold fractionation can greatly reduce infection attack rate as long as VE exceeds 1/n. This benefit threshold becomes more stringent if vaccine action is leaky (ie, the susceptibility of each vaccine recipient is reduced by a factor that is equal to the vaccine efficacy). The age cutoff for fractional-dose vaccines chosen by WHO for the Kinshasa vaccination campaign (2 years) provides the largest reduction in infection attack rate if the efficacy of 5-fold fractional-dose vaccines exceeds 20%. Dose fractionation is an effective strategy for reduction of the infection attack rate that would be robust with a

  6. Fractional Dosing of Yellow Fever Vaccine to Extend Supply: A Modeling Study

    Science.gov (United States)

    Peak, Corey M.; Leung, Gabriel M.

    2016-01-01

    Background The ongoing yellow fever (YF) epidemic in Angola strains the global vaccine supply, prompting WHO to adopt dose sparing for its vaccination campaign in Kinshasa in July–August 2016. Although a 5-fold fractional-dose vaccine is similar to standard-dose vaccine in safety and immunogenicity, efficacy is untested. There is an urgent need to ensure the robustness of fractional-dose vaccination by elucidating the conditions under which dose fractionation would reduce transmission. Methods We estimate the effective reproductive number for YF in Angola using disease natural history and case report data. With simple mathematical models of YF transmission, we calculate the infection attack rate (IAR, the proportion of population infected over the course of an epidemic) under varying levels of transmissibility and five-fold fractional-dose vaccine efficacy for two vaccination scenarios: (i) random vaccination in a hypothetical population that is completely susceptible; (ii) the Kinshasa vaccination campaign in July–August 2016 with different age cutoff for fractional-dose vaccines. Findings We estimate the effective reproductive number early in the Angola outbreak was between 5·2 and 7·1. If vaccine action is all-or-nothing (i.e. a proportion VE of vaccinees receives complete and the remainder receive no protection), n-fold fractionation can dramatically reduce IAR as long as efficacy VE exceeds 1/n. This benefit threshold becomes more stringent if vaccine action is leaky (i.e. the susceptibility of each vaccinee is reduced by a factor that is equal to the vaccine efficacy VE). The age cutoff for fractional-dose vaccines chosen by the WHO for the Kinshasa vaccination campaign (namely, 2 years) provides the largest reduction in IAR if the efficacy of five-fold fractional-dose vaccines exceeds 20%. Interpretation Dose fractionation is a very effective strategy for reducing infection attack rate that would be robust with a large margin for error in case

  7. Allogeneic bone marrow transplantation in adults after fractionated body irradiation and high dose cyclophosphamide

    International Nuclear Information System (INIS)

    Brinch, L.; Evensen, S.A.; Albrechtsen, D.; Egeland, T.; Solheim, B.G.; Rollag, H.; Naalsund, A.; Jacobsen, A.B.

    1991-01-01

    The authors present short and long-term results of allogeneic bone marrow transplantation after hyper-fractionated total body irradiation and high dose cyclophosphamide in ten patients treated for leukaemia during th period 1985-89. Three patients died from complications connected to the transplantation, while seven are living free from leukaemia 18 to 59 months after transplantation. Two patients need treatment for chronic graft versus host disease. Allogeneic bone marrow transplantation is expensive and risky. Close cooperation between clinicians and laboratory specialists is essential. The treatment increases long term survival and probably cures certain patients with leukaemia. Some of the patients will need treatment for chronic graft versus host disease and other late sequelae. 19 refs., 2 tabs

  8. Total-dose hardness assurance for low earth orbit

    International Nuclear Information System (INIS)

    Maurer, R.H.; Suter, J.J.

    1987-01-01

    The Low Earth Orbit radiation environment has two significant characteristics that make laboratory simulation exposures difficult: (1) a low dose rate and (2) many cycles of low dose accumulation followed by dose-free annealing. Hardness assurance considerations for this environment are discussed and related to data from the testing of Advanced Low Power Schottky and High-speed CMOS devices

  9. Xerostomia after radiotherapy. What matters - mean total dose or dose to each parotid gland?

    International Nuclear Information System (INIS)

    Tribius, S.; Sommer, J.; Prosch, C.; Bajrovic, A.; Kruell, A.; Petersen, C.; Muenscher, A.; Blessmann, M.; Todorovic, M.; Tennstedt, P.

    2013-01-01

    Purpose: Xerostomia is a debilitating side effect of radiotherapy in patients with head and neck cancer. We undertook a prospective study of the effect on xerostomia and outcomes of sparing one or both parotid glands during radiotherapy for patients with squamous cell carcinoma of the head and neck. Methods and materials: Patients with locally advanced squamous cell carcinoma of the head and neck received definitive (70 Gy in 2 Gy fractions) or adjuvant (60-66 Gy in 2 Gy fractions) curative-intent radiotherapy using helical tomotherapy with concurrent chemotherapy if appropriate. Group A received < 26 Gy to the left and right parotids and group B received < 26 Gy to either parotid. Results: The study included 126 patients; 114 (55 in group A and 59 in group B) had follow-up data. There were no statistically significant differences between groups in disease stage. Xerostomia was significantly reduced in group A vs. group B (p = 0.0381). Patients in group A also had significantly less dysphagia. Relapse-free and overall survival were not compromised in group A: 2-year relapse-free survival was 86% vs. 72% in group B (p = 0.361); 2-year overall survival was 88% and 76%, respectively (p = 0.251). Conclusion: This analysis suggests that reducing radiotherapy doses to both parotid glands to < 26 Gy can reduce xerostomia and dysphagia significantly without compromising survival. Sparing both parotids while maintaining target volume coverage and clinical outcome should be the treatment goal and reporting radiotherapy doses delivered to the individual parotids should be standard practice. (orig.)

  10. Xerostomia after radiotherapy. What matters - mean total dose or dose to each parotid gland?

    Energy Technology Data Exchange (ETDEWEB)

    Tribius, S.; Sommer, J.; Prosch, C.; Bajrovic, A.; Kruell, A.; Petersen, C. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Radiation Oncology; Muenscher, A. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Otorhinolaryngology and Head and Neck Surgery; Blessmann, M. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Oral and Maxillofacial Surgery; Todorovic, M. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Medical Physics; Tennstedt, P. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Martini-Clinic, Prostate Cancer Center

    2013-03-15

    Purpose: Xerostomia is a debilitating side effect of radiotherapy in patients with head and neck cancer. We undertook a prospective study of the effect on xerostomia and outcomes of sparing one or both parotid glands during radiotherapy for patients with squamous cell carcinoma of the head and neck. Methods and materials: Patients with locally advanced squamous cell carcinoma of the head and neck received definitive (70 Gy in 2 Gy fractions) or adjuvant (60-66 Gy in 2 Gy fractions) curative-intent radiotherapy using helical tomotherapy with concurrent chemotherapy if appropriate. Group A received < 26 Gy to the left and right parotids and group B received < 26 Gy to either parotid. Results: The study included 126 patients; 114 (55 in group A and 59 in group B) had follow-up data. There were no statistically significant differences between groups in disease stage. Xerostomia was significantly reduced in group A vs. group B (p = 0.0381). Patients in group A also had significantly less dysphagia. Relapse-free and overall survival were not compromised in group A: 2-year relapse-free survival was 86% vs. 72% in group B (p = 0.361); 2-year overall survival was 88% and 76%, respectively (p = 0.251). Conclusion: This analysis suggests that reducing radiotherapy doses to both parotid glands to < 26 Gy can reduce xerostomia and dysphagia significantly without compromising survival. Sparing both parotids while maintaining target volume coverage and clinical outcome should be the treatment goal and reporting radiotherapy doses delivered to the individual parotids should be standard practice. (orig.)

  11. Randomized trial of single dose versus fractionated palliative radiotherapy of bone metastases

    International Nuclear Information System (INIS)

    Nielsen, O.S.; Bentzen, S.M.; Sandberg, E.; Gadeberg, C.C.; Timothy, A.R.

    1998-01-01

    Purpose: Data in the literature suggest that for painful bone metastases a single dose is as effective as fractionated radiotherapy. In the present multicentre prospective trial, the effects of 8 Gy x1 and 5 Gy x4 were compared. Patients and methods: A total of 241 patients were randomized to 8 Gy (122 patients) or 20 Gy (119 patients). The primary tumour was in the breast in 39% of patients, in the prostate in 34% of patients, in the lung in 13% of patients and in other locations in 14% of patients. Outcome measures were pain relief as measured by VAS and in half of the patients also by a five-point categorical pain scale, global quality of life (QoL) and analgesic consumption. Evaluation was performed before and 4, 8, 12 and 20 weeks after treatment. Results: A total of 239 patients were evaluable for response. The two groups did not differ with respect to age, sex, primary tumour, metastasis localization, analgesic consumption (type and dose), performance status, prior systemic treatment, degree of pain and QoL. The treatment was completed as planned in 98% of patients. The degree of pain relief did not differ between the two treatment groups. At 4 weeks the difference in pain relief was 6% (95% CI 7, 20%) and at 8 weeks the difference was 13% (95% CI 3, 28%). Neither was there any significant difference in the duration of pain relief, the number of new painful sites and the need for reirradiation and toxicity was minor. Conclusion: The present randomized study showed that a single fraction of 8 Gy was as effective as 5 Gy x4 in relieving pain from bone metastasis. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. STELLAR AND TOTAL BARYON MASS FRACTIONS IN GROUPS AND CLUSTERS SINCE REDSHIFT 1

    International Nuclear Information System (INIS)

    Giodini, S.; Pierini, D.; Finoguenov, A.; Pratt, G. W.; Boehringer, H.; Leauthaud, A.; Guzzo, L.; Aussel, H.; Bolzonella, M.; Capak, P.; Elvis, M.; Hasinger, G.; Ilbert, O.; Kartaltepe, J. S.; Koekemoer, A. M.; Lilly, S. J.; Massey, R.; Rhodes, J.; Salvato, M.; McCracken, H. J.

    2009-01-01

    We investigate if the discrepancy between estimates of the total baryon mass fraction obtained from observations of the cosmic microwave background (CMB) and of galaxy groups/clusters persists when a large sample of groups is considered. To this purpose, 91 candidate X-ray groups/poor clusters at redshift 0.1 ≤ z ≤ 1 are selected from the COSMOS 2 deg 2 survey, based only on their X-ray luminosity and extent. This sample is complemented by 27 nearby clusters with a robust, analogous determination of the total and stellar mass inside R 500 . The total sample of 118 groups and clusters with z ≤ 1 spans a range in M 500 of ∼10 13 -10 15 M sun . We find that the stellar mass fraction associated with galaxies at R 500 decreases with increasing total mass as M -0.37±0.04 500 , independent of redshift. Estimating the total gas mass fraction from a recently derived, high-quality scaling relation, the total baryon mass fraction (f stars+gas 500 = f stars 500 + f gas 500 ) is found to increase by ∼25%, when M 500 increases from (M) = 5 x 10 13 M sun to (M) = 7 x 10 14 M sun . After consideration of a plausible contribution due to intracluster light (11%-22% of the total stellar mass) and gas depletion through the hierarchical assembly process (10% of the gas mass), the estimated values of the total baryon mass fraction are still lower than the latest CMB measure of the same quantity (WMAP5), at a significance level of 3.3σ for groups of (M) = 5 x 10 13 M sun . The discrepancy decreases toward higher total masses, such that it is 1σ at (M) = 7 x 10 14 M sun . We discuss this result in terms of nongravitational processes such as feedback and filamentary heating.

  13. Accelerated repopulation of mouse tongue epithelium during fractionated irradiations or following single doses

    International Nuclear Information System (INIS)

    Doerr, W.; Kummermehr, J.

    1990-01-01

    Mouse tongue mucosa was established as an animal model to study repopulation after large single doses or during continuous irradiation. A top-up irradiation technique was used employing priming doses or fractionated treatment to the whole snout (300 kV X-rays) followed by local test doses (25 kV X-rays) to elicit denudation in a confined field of the inferior tongue surface. Clearcut quantal dose-response curves of ulcer incidence were obtained to all protocols; animal morbidity, i.e. body weight loss was minimal. Repopulation following priming doses of 10 and 13 Gy started with a delay of at least 3 days and then progressed rapidly to nearly restore original tissue tolerance by day 11. During continuous fractionation over 1 to 3 weeks with 5 fractions/week and doses per fraction of 2.5, 3 and 3.5 Gy, repopulation was small in week one but subsequently increased to fully compensate the weekly dose at all dose levels. Additional measurements of cell density during a 4 weeks course of 5 x 3 Gy or 5 x 4 Gy per week showed only moderate depletion to 67% of the control figures. The fact that rapid repopulation is achieved at relatively moderate damage levels should be taken into account when the timing of a treatment split is considered. (author). 18 refs.; 7 figs.; 1 tab

  14. The optimal fraction size in high-dose-rate brachytherapy: dependency on tissue repair kinetics and low-dose rate

    International Nuclear Information System (INIS)

    Sminia, Peter; Schneider, Christoph J.; Fowler, Jack F.

    2002-01-01

    Background and Purpose: Indications of the existence of long repair half-times on the order of 2-4 h for late-responding human normal tissues have been obtained from continuous hyperfractionated accelerated radiotherapy (CHART). Recently, these data were used to explain, on the basis of the biologically effective dose (BED), the potential superiority of fractionated high-dose rate (HDR) with large fraction sizes of 5-7 Gy over continuous low-dose rate (LDR) irradiation at 0.5 Gy/h in cervical carcinoma. We investigated the optimal fraction size in HDR brachytherapy and its dependency on treatment choices (overall treatment time, number of HDR fractions, and time interval between fractions) and treatment conditions (reference low-dose rate, tissue repair characteristics). Methods and Materials: Radiobiologic model calculations were performed using the linear-quadratic model for incomplete mono-exponential repair. An irradiation dose of 20 Gy was assumed to be applied either with HDR in 2-12 fractions or continuously with LDR for a range of dose rates. HDR and LDR treatment regimens were compared on the basis of the BED and BED ratio of normal tissue and tumor, assuming repair half-times between 1 h and 4 h. Results: With the assumption that the repair half-time of normal tissue was three times longer than that of the tumor, hypofractionation in HDR relative to LDR could result in relative normal tissue sparing if the optimum fraction size is selected. By dose reduction while keeping the tumor BED constant, absolute normal tissue sparing might therefore be achieved. This optimum HDR fraction size was found to be largely dependent on the LDR dose rate. On the basis of the BED NT/TUM ratio of HDR over LDR, 3 x 6.7 Gy would be the optimal HDR fractionation scheme for replacement of an LDR scheme of 20 Gy in 10-30 h (dose rate 2-0.67 Gy/h), while at a lower dose rate of 0.5 Gy/h, four fractions of 5 Gy would be preferential, still assuming large differences between tumor

  15. Perioperative fractionated high-dose rate brachytherapy for malignant bone and soft tissue tumors

    International Nuclear Information System (INIS)

    Koizumi, Masahiko; Inoue, Takehiro; Yamazaki, Hideya; Teshima, Teruki; Tanaka, Eiichi; Yoshida, Ken; Imai, Atsushi; Shiomi, Hiroya; Kagawa, Kazufumi; Araki, Nobuto; Kuratsu, Shigeyuki; Uchida, Atsumasa; Inoue, Toshihiko

    1999-01-01

    Purpose: To investigate the viability of perioperative fractionated HDR brachytherapy for malignant bone and soft tissue tumors, analyzing the influence of surgical margin. Methods and Materials: From July 1992 through May 1996, 16 lesions of 14 patients with malignant bone and soft tissue tumors (3 liposarcomas, 3 MFHs, 2 malignant schwannomas, 2 chordomas, 1 osteosarcoma, 1 leiomyosarcoma, 1 epithelioid sarcoma, and 1 synovial sarcoma) were treated at the Osaka University Hospital. The patients' ages ranged from 14 to 72 years (median: 39 years). Treatment sites were the pelvis in 6 lesions, the upper limbs in 5, the neck in 4, and a lower limb in 1. The resection margins were classified as intracapsular in 5 lesions, marginal in 5, and wide in 6. Postoperative fractionated HDR brachytherapy was started on the 4th-13th day after surgery (median: 6th day). The total dose was 40-50 Gy/7-10 fr/ 4-7 day (bid) at 5 or 10 mm from the source. Follow-up periods were between 19 and 46 months (median: 30 months). Results: Local control rates were 75% at 1 year and 48% in 2 years, and ultimate local control was achieved in 8 (50%) of 16 lesions. Of the 8 uncontrolled lesions, 5 (63%) had intracapsular (macroscopically positive) resection margins, and all the 8 controlled lesions (100%) had marginal (microscopically positive) or wide (negative) margins. Of the total, 3 patients died of both tumor and metastasis, 3 of metastasis alone, 1 of tumor alone, and 7 showed no evidence of disease. Peripheral nerve palsy was seen in one case after this procedure, but no infection or delayed wound healing caused by tubing or irradiation has occurred. Conclusion: Perioperative fractionated HDR brachytherapy is safe, well tolerated, and applicable to marginal or wide surgical margin cases

  16. High-dose rate fractionated interstitial radiotherapy for oropharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Nose, Takayuki; Inoue, Toshihiko; Inoue, Takehiro; Teshima, Teruki; Murayama, Shigeyuki [Osaka Univ. (Japan). Faculty of Medicine

    1995-03-01

    The limitations of treating oropharyngeal cancer patients with definitive external radiotherapy are the complications of salivary glands, taste buds, mandible and temporomandibular joints. To avoid these complications we started interstitial radiotherapy as boost after 46 Gy of external radiotherapy. Ten cases (retromolar trigone; 1, soft palate; 1, base of tongue; 3, lateral wall; 5) were treated with this method and seven cases were controlled locally. With short follow-up period, xerostomia and dysgeusia are less than definitive external radiotherapy as clinical impression and no in-field recurrences have been experienced. With markedly increased tumor dose, the local control rate can be improved. This treatment method will be an alternative to definitive external radiotherapy to gain better QOL and higher control rate. (author).

  17. Improvements in dose calculation accuracy for small off-axis targets in high dose per fraction tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hardcastle, Nicholas; Bayliss, Adam; Wong, Jeannie Hsiu Ding; Rosenfeld, Anatoly B.; Tome, Wolfgang A. [Department of Human Oncology, University of Wisconsin-Madison, WI, 53792 (United States); Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, VIC 3002 (Australia) and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); Department of Human Oncology, University of Wisconsin-Madison, WI 53792 (United States); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia) and Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Einstein Institute of Oncophysics, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461 (United States) and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2012-08-15

    Purpose: A recent field safety notice from TomoTherapy detailed the underdosing of small, off-axis targets when receiving high doses per fraction. This is due to angular undersampling in the dose calculation gantry angles. This study evaluates a correction method to reduce the underdosing, to be implemented in the current version (v4.1) of the TomoTherapy treatment planning software. Methods: The correction method, termed 'Super Sampling' involved the tripling of the number of gantry angles from which the dose is calculated during optimization and dose calculation. Radiochromic film was used to measure the dose to small targets at various off-axis distances receiving a minimum of 21 Gy in one fraction. Measurements were also performed for single small targets at the center of the Lucy phantom, using radiochromic film and the dose magnifying glass (DMG). Results: Without super sampling, the peak dose deficit increased from 0% to 18% for a 10 mm target and 0% to 30% for a 5 mm target as off-axis target distances increased from 0 to 16.5 cm. When super sampling was turned on, the dose deficit trend was removed and all peak doses were within 5% of the planned dose. For measurements in the Lucy phantom at 9.7 cm off-axis, the positional and dose magnitude accuracy using super sampling was verified using radiochromic film and the DMG. Conclusions: A correction method implemented in the TomoTherapy treatment planning system which triples the angular sampling of the gantry angles used during optimization and dose calculation removes the underdosing for targets as small as 5 mm diameter, up to 16.5 cm off-axis receiving up to 21 Gy.

  18. Improvements in dose calculation accuracy for small off-axis targets in high dose per fraction tomotherapy

    International Nuclear Information System (INIS)

    Hardcastle, Nicholas; Bayliss, Adam; Wong, Jeannie Hsiu Ding; Rosenfeld, Anatoly B.; Tomé, Wolfgang A.

    2012-01-01

    Purpose: A recent field safety notice from TomoTherapy detailed the underdosing of small, off-axis targets when receiving high doses per fraction. This is due to angular undersampling in the dose calculation gantry angles. This study evaluates a correction method to reduce the underdosing, to be implemented in the current version (v4.1) of the TomoTherapy treatment planning software. Methods: The correction method, termed “Super Sampling” involved the tripling of the number of gantry angles from which the dose is calculated during optimization and dose calculation. Radiochromic film was used to measure the dose to small targets at various off-axis distances receiving a minimum of 21 Gy in one fraction. Measurements were also performed for single small targets at the center of the Lucy phantom, using radiochromic film and the dose magnifying glass (DMG). Results: Without super sampling, the peak dose deficit increased from 0% to 18% for a 10 mm target and 0% to 30% for a 5 mm target as off-axis target distances increased from 0 to 16.5 cm. When super sampling was turned on, the dose deficit trend was removed and all peak doses were within 5% of the planned dose. For measurements in the Lucy phantom at 9.7 cm off-axis, the positional and dose magnitude accuracy using super sampling was verified using radiochromic film and the DMG. Conclusions: A correction method implemented in the TomoTherapy treatment planning system which triples the angular sampling of the gantry angles used during optimization and dose calculation removes the underdosing for targets as small as 5 mm diameter, up to 16.5 cm off-axis receiving up to 21 Gy.

  19. SU-E-T-480: Radiobiological Dose Comparison of Single Fraction SRS, Multi-Fraction SRT and Multi-Stage SRS of Large Target Volumes Using the Linear-Quadratic Formula

    International Nuclear Information System (INIS)

    Ding, C; Hrycushko, B; Jiang, S; Meyer, J; Timmerman, R

    2014-01-01

    Purpose: To compare the radiobiological effect on large tumors and surrounding normal tissues from single fraction SRS, multi-fractionated SRT, and multi-staged SRS treatment. Methods: An anthropomorphic head phantom with a centrally located large volume target (18.2 cm 3 ) was scanned using a 16 slice large bore CT simulator. Scans were imported to the Multiplan treatment planning system where a total prescription dose of 20Gy was used for a single, three staged and three fractionated treatment. Cyber Knife treatment plans were inversely optimized for the target volume to achieve at least 95% coverage of the prescription dose. For the multistage plan, the target was segmented into three subtargets having similar volume and shape. Staged plans for individual subtargets were generated based on a planning technique where the beam MUs of the original plan on the total target volume are changed by weighting the MUs based on projected beam lengths within each subtarget. Dose matrices for each plan were export in DICOM format and used to calculate equivalent dose distributions in 2Gy fractions using an alpha beta ratio of 10 for the target and 3 for normal tissue. Results: Singe fraction SRS, multi-stage plan and multi-fractionated SRT plans had an average 2Gy dose equivalent to the target of 62.89Gy, 37.91Gy and 33.68Gy, respectively. The normal tissue within 12Gy physical dose region had an average 2Gy dose equivalent of 29.55Gy, 16.08Gy and 13.93Gy, respectively. Conclusion: The single fraction SRS plan had the largest predicted biological effect for the target and the surrounding normal tissue. The multi-stage treatment provided for a more potent biologically effect on target compared to the multi-fraction SRT treatments with less biological normal tissue than single-fraction SRS treatment

  20. Response of rat spinal cord to single and fractionated doses of accelerated heavy ions

    International Nuclear Information System (INIS)

    Leith, J.L.; McDonald, M.; Powers-Risius, P.; Bliven, S.F.; Walton, R.E.; Woodruff, K.H.; Howard, J.

    1980-01-01

    The response of rat spinal cord to irradiation with accelerated heavy ions, in particular carbon and neon ions has been studied. Two different ionization regions in the modified Bragg curve for each ion have been studied for both single and fractionated exposures. We have defined the paralytic response as a function of dose and dose per fraction, and we have determined RBE and repair values. The response of rat spinal cord is both dose and LET dependent, which allows the derivation of RBE and repair values

  1. Effects of total dose of ionizing radiation on integrated circuits

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Marcilei A.G.; Cirne, K.H.; Gimenez, S.; Santos, R.B.B. [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil); Added, N.; Barbosa, M.D.L.; Medina, N.H.; Tabacniks, M.H. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Lima, J.A. de; Seixas Junior, L.E.; Melo, W. [Centro de Tecnologia da Informacao Paulo Archer, Sao Paulo, SP (Brazil)

    2011-07-01

    Full text: The study of ionizing radiation effects on materials used in electronic devices is of great relevance for the progress of global technological development and, particularly, it is a necessity in some strategic areas in Brazil. Electronic circuits are strongly influenced by radiation and the need for IC's featuring radiation hardness is largely growing to meet the stringent environment in space electronics. On the other hand, aerospace agencies are encouraging both scientific community and semiconductors industry to develop hardened-by-design components using standard manufacturing processes to achieve maximum performance, while significantly reducing costs. To understand the physical phenomena responsible for changes in devices exposed to ionizing radiation several kinds of radiation should then be considered, among them alpha particles, protons, gamma and X-rays. Radiation effects on the integrated circuits are usually divided into two categories: total ionizing dose (TID), a cumulative dose that shifts the threshold voltage and increases transistor's off-state current; single events effects (SEE), a transient effect which can deposit charge directly into the device and disturb the properties of electronic circuits. TID is one of the most common effects and may generate degradation in some parameters of the CMOS electronic devices, such as the threshold voltage oscillation, increase of the sub-threshold slope and increase of the off-state current. The effects of ionizing radiation are the creation of electron-hole pairs in the oxide layer changing operation mode parameters of the electronic device. Indirectly, there will be also changes in the device due to the formation of secondary electrons from the interaction of electromagnetic radiation with the material, since the charge carriers can be trapped both in the oxide layer and in the interface with the oxide. In this work we have investigated the behavior of MOSFET devices fabricated with

  2. Effects of low-dose fractionated external irradiation on metabolic and structural characteristics of rat thyroid

    Energy Technology Data Exchange (ETDEWEB)

    Nadolnik, L.; Niatsetskaya, Z. [Institute of Biochemistry, National Academy of Sciences of Belarus, Grodno (Belarus)

    2006-07-01

    Full text of publication follows: The problem of thyroid radiosensitivity to the effect of low dose external ionizing irradiation presently seems to be the least studied, and the experimental findings - the most contradictory. The aim of the work was to study the effects of long-term low-dose fractionated irradiation on the iodide metabolism and structure of the thyroid. Female Wistar rats weighing 140-160 g were irradiated 20 times (5 times a week, for 4 weeks) using a 60 Co installation. The single absorbed doses were 0.1, 0.25 and 0.5 Gy and the total ones - 2.0, 5.0 and 10.0 Gy, respectively. The animals were decapitated after 1 day, 4 and 24 weeks following the last irradiation. The thyroid tissue was used to assay for thyro-peroxidase (T.P.O.) activity as well as total, protein -bound and free iodide concentrations. Microscopic and morphometric examination of histologic thyroid preparations was carried out. Blood was assayed for thyroxin (T4) and triiodothyronine (T3) concentrations. After a day following the irradiation, the thyroid showed a pronounced increase in the concentration of total iodide (30.0-54.4%) as well in that of free (32.1-60.8%) and protein-bound ones (24.4-37.4%). The most pronounced iodide concentration elevation was noted in the 0.1 -Gy animals, with thyroid T.P.O. activity being raised by 48.0%. Only the 0.5 Gy-group had 1.4-1.5-fold reduced thyroid hormone levels. Four weeks after the irradiation, studied parameters of irradiated rats were brought back to the control values, except for the 0.5 Gy-group. However, after 24-weeks, the 0.5-and 0.25- irradiated rats experienced a 12-20% thyroid weight elevation in comparison with the control. The thyroid of these animals demonstrated reduced contents of total and free iodide as well as T.P.O. activity by 24.5 and 34.8%. The 0.1 Gy-group had a 1.7-fold increased T.P.O. activity. The concentration of the thyroid hormones was maintained diminished only in the 0.5 Gy -irradiated group. However

  3. Colon mucosal cells after high-dose fractional irradiation

    International Nuclear Information System (INIS)

    Zorc-Pleskovic, R.; Vraspir-Porenta, O.; Petrovic, D.; Zorc, M.; Pleskovic, L.

    2000-01-01

    The aim of this study was to investigate histological and stereological changes in cryptal enterocytes, mucosal lymphocytes and mast cells 10 days after irradiation. For experimental model, 24 Beagle dogs 1-2 years old were used. Twelve dogs were irradiated 20 days with 32 Gy over the whole pelvis and tail. Another 12 dogs represented a control group. For the detection of apoptosis, the TUNEL technique was used. Histological and stereological analyses were performed using a Wild sampling microscope M 1000. In the irradiated group, volume density (P < 0.01), numerical density (P < 0.05) and average volume of lymphocytes (P < 0.001) were significantly lower than in the nonirradiated group. Numerical areal density of mast cells in the irradiated group was also significantly lower (P < 0.05). Volume density (P < 0.001) and average volume of mast cells (P < 0.001) were significantly higher in the irradiated group. The results of our experiments show that irradiation causes injury and loss of lymphocytes and mast cells in the colon mucosa. Apoptosis was detected in enterocytes and lymphocytes in the irradiated group and in nonirradiated group in equal numbers (2.5 ± 0.3 vs. 2.3 ± 0.3; ns.), suggesting that 10 days after high-dose irradiation, the cell loss is not due to apoptosis. (author)

  4. Relationship of dose rate and total dose to responses of continuously irradiated beagles

    International Nuclear Information System (INIS)

    Fritz, T.E.; Norris, W.P.; Tolle, D.V.; Seed, T.M.; Poole, C.M.; Lombard, L.S.; Doyle, D.E.

    1978-01-01

    Young-adult beagles were exposed continuously (22 hours/day) to 60 Co γ rays in a specially constructed facility. The exposure rates were either 5, 10, 17, or 35 R/day, and the exposures were terminated at either 600, 1400, 2000, or 4000 R. A total of 354 dogs were irradiated; 221 are still alive as long-term survivors, some after more than 2000 days. The data on survival of these dogs, coupled with data from similar preliminary experiments, allow an estimate of the LD 50 for γ-ray exposures given at a number of exposure rates. They also allow comparison of the relative importance of dose rate and total dose, and the interaction of these two variables, in the early and late effects after protracted irradiation. The LD 50 for the beagle increases from 258 rad delivered at 15 R/minute to approximately 3000 rad at 10 R/day. Over this entire range, the LD 50 is dependent upon hematopoietic damage. At 5 R/day and less, no meaningful LD 50 can be determined; there is nearly normal continued hematopoietic function, survival is prolonged, and the dogs manifest varied individual responses in other organ systems. Although the experiment is not complete, interim data allow several important conclusions. Terminated exposures, while not as effective as radiation continued until death, can produce myelogenous leukemia at the same exposure rate, 10 R/day. More importantly, at the same total accumulated dose, lower exposure rates are more damaging than higher rates on the basis of the rate and degree of hematological recovery that occurs after termination of irradiation. Thus, the rate of hematologic depression, the nadir of the depression, and the rate of recovery are dependent upon exposure rate; the latter is inversely related and the former two are directly related to exposure rate

  5. Relationship of dose rate and total dose to responses of continuously irradiated beagles

    International Nuclear Information System (INIS)

    Fritz, T.E.; Norris, W.P.; Tolle, D.V.; Seed, T.M.; Poole, C.M.; Lombard, L.S.; Doyle, D.E.

    1978-01-01

    Young-adult beagles were exposed continuously (22 hours/day) to 60 Co gamma rays in a specially constructed facility. The exposure rates were 5, 19, 17 or 35 R/day, and the exposures were terminated at 600, 1400, 2000 or 4000 R. A total of 354 dogs were irradiated; 221 are still alive as long-term survivors, some after more than 2000 days. The data on survival of these dogs, coupled with data from similar preliminary experiments, allow an estimate of the LD 50 for gamma-ray exposures given at a number of exposure rates. They also allow comparison of the relativeimportance of dose rate and total dose, and the interaction of these two variables, in the early and late effects after protracted irradiation. The LD 50 for the beagle increases from 344 R (258 rads) delivered at 15 R/minute to approximately 4000 R (approximately 3000 rads) at 10 R/day. Over this entire range, the LD 50 is dependent upon haematopoietic damage. At 5 R/day and less, no definitive LD 50 can be determined; there is nearly normal continued haematopoietic function, survival is prolonged, and the dogs manifest varied individual responses in the organ systems. Although the experiment is not complete, interim data allow serveral important conclusions. Terminated exposures, while not as effective as irradiation continued until death, can produce myelogenous leukaemia at the same exposure rate, 10 R/day. More importantly, at the same total accumulated dose, lower exposure rates appear more damaging than higher rates on the basis of the rate and degree of haematological recovery that occurs after termination of irradiation. Thus, the rate of haematologic depression, the nadir of the depression and the rate of recovery are dependent upon exposure rate; the latter is inversely related and the first two are directly related to exposure rate. ( author)

  6. Some thoughts on tolerance, dose, and fractionation in boron neutron capture therapy

    International Nuclear Information System (INIS)

    Gahbauer, R.; Goodman, J.; Blue, T.

    1988-01-01

    Unique to boron neutron capture therapy, the tolerance very strongly depends on the boron concentration in normal brain, skin and blood. If one first considers the ideal situation of a 2 KeV beam and a compound clearing from normal tissues and blood, the tolerance dose to epithermal beams relates to the maximum tolerated capture gamma dose and capture high LET dose, H (n,gamma)D and N(n,p) 14 C. The authors can relate this gamma and high LET dose to known clinical experience. Assuming gamma and high LET dose ratios as given by Fairchild and Bond, one may first choose a clearly safe high LET whole brain dose and calculate the unavoidably resulting gamma dose. To a first approximation 500 cGy of high LET dose results in 3,000 cGy gamma dose. One can speculate that this approximates the tolerance of whole brain to the 2 KeV beam with no contributing boron dose if the radiation is fractionated. It would clearly be beyond tolerance in a single fraction where most therapists would be uncomfortable to deliver even one third of the above doses

  7. In vivo dosimetry of high-dose fractionated irradiation in an experimental set-up with rats

    Energy Technology Data Exchange (ETDEWEB)

    Fortan, L; Van Hecke, H; Van Duyse, B; De Neve, W; De Meerleer, B [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde; Pattyn, P; Van Renthergem, K [Ghent University (Belgium). Dept. of Surgery

    1995-12-01

    The feasibility to irradiate a limited section of a rat abdomen with well-defined edges was assessed. Because of the relative small volume involved, in vivo dosimetry with TLDs was necessary in providing us information about the accuracy of the irradiation method. Three to five days prior to the start of the radiotherapy treatment, two plastic strips - each containing a TLD-dosimeter (Harshaw TLD10 LiF rods, 1 mm dia x 6 mm) sealed in polyethylene tubing, and a lead bean - were implanted in the rat abdomen. The plastic strips made a closed loop around the bowel, through the mesenterium, and were fixed with a single stitch on the inner abdominal wall. One loop was made in the hepatic area; another was made in the lower abdomen, around the rectosigmoid. Conscious animals were irradiated using a purpose-build plexi-holder, with rear legs immobilised to avoid longitudinal movements. The implanted lead beans enabled us to simulate the rat prior to each radiation session. This way, the radiation field could be set up individually for each rat, in such way that the rectosigmoid area received full dose and the hepatic area received no irradiation dose at all. Irradiation was carried out, using 5 MV photons of a linear accelerator. Fifteen animals per group were irradiated according a conventional (2.0 Gy / fraction; 5 fractions / week) or a hyperfractionated (1.6 Gy / fraction; 2 daily fractions; 5 days / week) schedule, with different total doses. Prior to implantation, TLDs were individually calibrated and checked for stability. After removal from the abdomen . TLDs were tested again for accuracy. TLDs with an unacceptable read-out curve were rejected (about 2 to 4 TLDs per group of 15). The obtained accumulated doses - as determined by TLD read-outs-were comparable to the theoretical doses, indicating that fractionated radiation of small fields, with well defined mark off, in rats is feasible.

  8. In vivo dosimetry of high-dose fractionated irradiation in an experimental set-up with rats

    International Nuclear Information System (INIS)

    Fortan, L.; Van Hecke, H.; Van Duyse, B.; De Neve, W.; De Meerleer, B.; Pattyn, P.; Van Renthergem, K.

    1995-01-01

    The feasibility to irradiate a limited section of a rat abdomen with well-defined edges was assessed. Because of the relative small volume involved, in vivo dosimetry with TLDs was necessary in providing us information about the accuracy of the irradiation method. Three to five days prior to the start of the radiotherapy treatment, two plastic strips - each containing a TLD-dosimeter (Harshaw TLD10 LiF rods, 1 mm dia x 6 mm) sealed in polyethylene tubing, and a lead bean - were implanted in the rat abdomen. The plastic strips made a closed loop around the bowel, through the mesenterium, and were fixed with a single stitch on the inner abdominal wall. One loop was made in the hepatic area; another was made in the lower abdomen, around the rectosigmoid. Conscious animals were irradiated using a purpose-build plexi-holder, with rear legs immobilised to avoid longitudinal movements. The implanted lead beans enabled us to simulate the rat prior to each radiation session. This way, the radiation field could be set up individually for each rat, in such way that the rectosigmoid area received full dose and the hepatic area received no irradiation dose at all. Irradiation was carried out, using 5 MV photons of a linear accelerator. Fifteen animals per group were irradiated according a conventional (2.0 Gy / fraction; 5 fractions / week) or a hyperfractionated (1.6 Gy / fraction; 2 daily fractions; 5 days / week) schedule, with different total doses. Prior to implantation, TLDs were individually calibrated and checked for stability. After removal from the abdomen . TLDs were tested again for accuracy. TLDs with an unacceptable read-out curve were rejected (about 2 to 4 TLDs per group of 15). The obtained accumulated doses - as determined by TLD read-outs-were comparable to the theoretical doses, indicating that fractionated radiation of small fields, with well defined mark off, in rats is feasible

  9. Dose-escalated total body irradiation and autologous stem cell transplantation for refractory hematologic malignancy

    International Nuclear Information System (INIS)

    McAfee, Steven L.; Powell, Simon N.; Colby, Christine; Spitzer, Thomas R.

    2002-01-01

    Purpose: To evaluate the feasibility of dose escalation of total body irradiation (TBI) above the previously reported maximally tolerated dose, we have undertaken a Phase I-II trial of dose-escalated TBI with autologous peripheral blood stem cell transplantation (PBSCT) for chemotherapy-refractory lymphoma. Methods and Materials: Nine lymphoma patients with primary refractory disease (PRD) or in resistant relapse (RR) received dose-escalated TBI and PBSCT. The three dose levels of fractionated TBI (200 cGy twice daily) were 1,600 cGy, 1,800 cGy, and 2,000 cGy. Lung blocks were used to reduce the TBI transmission dose by 50%, and the chest wall dose was supplemented to the prescribed dose using electrons. Shielding of the kidneys was performed to keep the maximal renal dose at 1,600 cGy. Three patients, two with non-Hodgkin's lymphoma (NHL) in RR and one with PRD Hodgkin's disease, received 1,600 cGy + PBSCT, three patients (two NHL in RR, one PRD) received 1,800 cGy + PBSCT, and three patients with NHL (two in RR, one PRD) received 2,000 cGy + PBSCT. Results: Toxicities associated with this high-dose TBI regimen included reversible hepatic veno-occlusive disease in 1 patient, Grade 2 mucositis requiring narcotic analgesics in 8 patients, and neurologic toxicities consisting of a symmetrical sensory neuropathy (n=4) and Lhermitte's syndrome (n=1). Interstitial pneumonitis developed in 1 patient who received 1,800 cGy after receiving recombinant α-interferon (with exacerbation after rechallenge with interferon). Six (66%) patients achieved a response. Four (44%) patients achieved complete responses, three of which were of a duration greater than 1 year, and 2 (22%) patients achieved a partial response. One patient remains disease-free more than 5 years posttransplant. Corticosteroid-induced gastritis and postoperative infection resulted in the death of 1 patient in complete response, 429 days posttransplant. Conclusion: TBI in a dose range 1,600-2,000 cGy as

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  11. New Insights into Fully-Depleted SOI Transistor Response During Total Dose Irradiation

    International Nuclear Information System (INIS)

    Burns, J.A.; Dodd, P.E.; Keast, C.L.; Schwank, J.R.; Shaneyfelt, M.R.; Wyatt, P.W.

    1999-01-01

    Worst-case bias configuration for total-dose testing fully-depleted SOI transistors was found to be process dependent. No evidence was found for total-dose induced snap back. These results have implications for hardness assurance testing

  12. A pilot study to evaluate the cost-effectiveness of ondansetron and granisetron in fractionated total body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, S.J.; Cassoni, A.M. [Middlesex Hospital, London (United Kingdom)

    1996-11-01

    The duration of the antiemetic effect of granisetron was examined in a pilot study of patients (n = 26) undergoing a standard emetogenic stimulus in the form of total body irradiation fractionated over 3-4 days, in a randomized comparison with twice-daily ondansetron. A single intravenous dose of granisetron at the onset of therapy was effective over the entire follow-up period in 50% (6/12) of patients, compared with 77% (10/13) prescribed twice-daily oral ondansetron for 3 or 4 days. The response rate within the first 24 hours from the start of irradiation was 67% (8/12) for granisetron and 77% (10/13) for ondansetron. Granisetron and ondansetron was therefore of similar efficacy within the first 24-hour period, but granisetron was less efficaceous more than 24 hours after the onset of therapy. Patients who required a second dose of granisetron did so at intervals of 12, 42, 47 and 48 hours following the first fraction of radiotherapy. The cost per patient in this study was 48 for granisetron and {sub 1}54 for ondanestron, but the dose scheduling we used cannot be recommended in view of the lower effectiveness of granisetron. (author).

  13. A pilot study to evaluate the cost-effectiveness of ondansetron and granisetron in fractionated total body irradiation

    International Nuclear Information System (INIS)

    Gibbs, S.J.; Cassoni, A.M.

    1996-01-01

    The duration of the antiemetic effect of granisetron was examined in a pilot study of patients (n = 26) undergoing a standard emetogenic stimulus in the form of total body irradiation fractionated over 3-4 days, in a randomized comparison with twice-daily ondansetron. A single intravenous dose of granisetron at the onset of therapy was effective over the entire follow-up period in 50% (6/12) of patients, compared with 77% (10/13) prescribed twice-daily oral ondansetron for 3 or 4 days. The response rate within the first 24 hours from the start of irradiation was 67% (8/12) for granisetron and 77% (10/13) for ondansetron. Granisetron and ondansetron was therefore of similar efficacy within the first 24-hour period, but granisetron was less efficaceous more than 24 hours after the onset of therapy. Patients who required a second dose of granisetron did so at intervals of 12, 42, 47 and 48 hours following the first fraction of radiotherapy. The cost per patient in this study was 48 for granisetron and 1 54 for ondanestron, but the dose scheduling we used cannot be recommended in view of the lower effectiveness of granisetron. (author)

  14. Dose compensation of the total body irradiation therapy

    International Nuclear Information System (INIS)

    Lin, J.-P.; Chu, T.-C.; Liu, M.-T.

    2001-01-01

    The aim of the study is to improve dose uniformity in the body by the compensator-rice and to decrease the dose to the lung by the partial lung block. Rando phantom supine was set up to treat bilateral fields with a 15 MV linear accelerator at 415 cm treatment distance. The experimental procedure included three parts. The first part was the bilateral irradiation without rice compensator, and the second part was with rice compensator. In the third part, rice compensator and partial lung block were both used. The results of thermoluminescent dosimeters measurements indicated that without rice compensator the dose was non-uniform. Contrarily, the average dose homogeneity with rice compensator was measured within ±5%, except for the thorax region. Partial lung block can reduce the dose which the lung received. This is a simple method to improve the dose homogeneity and to reduce the lung dose received. The compensator-rice is cheap, and acrylic boxes are easy to obtain. Therefore, this technique is suitable for more studies

  15. Dose-rate effects in synchronous mammalian cells in culture. II. A comparison of the life cycle of HeLa cells during continuous irradiation or multiple-dose fractionation

    International Nuclear Information System (INIS)

    Mitchell, J.B.; Bedford, J.S.

    1977-01-01

    The life cycle of synchronized S3 HeLa cells was examined during continuous irradiation at a dose rate of approximately 37 rad/hr and during multiple dose fractionation schedules of the same average dose rate (total dose / overall time = average dose rate). For all regimes given at this dose rate the effects on the life cyclee were similar. Cells progressed through G1 and S without appreciable delay and experienced a minimum G2 delay of about 10 hr. Cells eventually entered mitosis but virtually none were able to complete a successful division

  16. Recalculation of dose for each fraction of treatment on TomoTherapy.

    Science.gov (United States)

    Thomas, Simon J; Romanchikova, Marina; Harrison, Karl; Parker, Michael A; Bates, Amy M; Scaife, Jessica E; Sutcliffe, Michael P F; Burnet, Neil G

    2016-01-01

    The VoxTox study, linking delivered dose to toxicity requires recalculation of typically 20-37 fractions per patient, for nearly 2000 patients. This requires a non-interactive interface permitting batch calculation with multiple computers. Data are extracted from the TomoTherapy(®) archive and processed using the computational task-management system GANGA. Doses are calculated for each fraction of radiotherapy using the daily megavoltage (MV) CT images. The calculated dose cube is saved as a digital imaging and communications in medicine RTDOSE object, which can then be read by utilities that calculate dose-volume histograms or dose surface maps. The rectum is delineated on daily MV images using an implementation of the Chan-Vese algorithm. On a cluster of up to 117 central processing units, dose cubes for all fractions of 151 patients took 12 days to calculate. Outlining the rectum on all slices and fractions on 151 patients took 7 h. We also present results of the Hounsfield unit (HU) calibration of TomoTherapy MV images, measured over an 8-year period, showing that the HU calibration has become less variable over time, with no large changes observed after 2011. We have developed a system for automatic dose recalculation of TomoTherapy dose distributions. This does not tie up the clinically needed planning system but can be run on a cluster of independent machines, enabling recalculation of delivered dose without user intervention. The use of a task management system for automation of dose calculation and outlining enables work to be scaled up to the level required for large studies.

  17. Tumor and normal tissue responses to fractioned non-uniform dose delivery

    Energy Technology Data Exchange (ETDEWEB)

    Kaellman, P; Aegren, A; Brahme, A [Karolinska Inst., Stockholm (Sweden). Dept. of Radiation Physics

    1996-08-01

    The volume dependence of the radiation response of a tumor is straight forward to quantify because it depends primarily on the eradication of all its clonogenic cells. A tumor therefore has a parallel organization as any surviving clonogen in principle can repopulate the tumor. The difficulty with the response of the tumor is instead to know the density and sensitivity distribution of the most resistant clonogenic cells. The increase in the 50% tumor control dose and the decrease in the maximum normalized slope of the dose response relation, {gamma}, in presence of small compartments of resistant tumor cells have therefore been quantified to describe their influence on the dose response relation. Injury to normal tissue is a much more complex and gradual process. It depends on earlier effects induced long before depletion of the differentiated and clonogenic cells that in addition may have a complex structural and functional organization. The volume dependence of the dose response relation of normal tissues is therefore described here by the relative seriality, s, of the infrastructure of the organ. The model can also be generalized to describe the response of heterogeneous tissues to non uniform dose distributions. The new model is compared with clinical and experimental data on normal tissue response, and shows good agreement both with regard to the shape of dose response relation and the volume dependence of the isoeffect dose. The response of tumors and normal tissues are quantified for arbitrary dose fractionations using the linear quadratic cell survival parameters {alpha} and {beta}. The parameters of the dose response relation are derived both for a constant dose per fraction and a constant number of dose fractions, thus in the latter case accounting also for non uniform dose delivery. (author). 26 refs, 4 figs.

  18. Long-term renal toxicity in children following fractionated total-body irradiation (TBI) before allogeneic stem cell transplantation (SCT)

    International Nuclear Information System (INIS)

    Gerstein, Johanna; Meyer, Andreas; Fruehauf, Joerg; Karstens, Johann H.; Bremer, Michael; Sykora, Karl-Walter

    2009-01-01

    Purpose: to retrospectively assess the incidence and time course of renal dysfunction in children (≤ 16 years) following total-body irradiation (TBI) before allogeneic stem cell transplantation (SCT). Patients and methods: between 1986 and 2003, 92 children (median age, 11 years; range, 3-16 years) underwent TBI before allogeneic SCT. 43 of them had a minimum follow-up of 12 months (median, 51 months; range, 12-186 months) and were included into this analysis. Conditioning regimen included chemotherapy and fractionated TBI with 12 Gy (n = 26) or 11.1 Gy (n = 17). In one patient, renal dose was limited to 10 Gy by customized renal shielding due to known nephropathy prior to SCt. Renal dysfunction was defined as an increase of serum creatinine > 1.25 times the upper limit of age-dependent normal. Results: twelve children (28%) experienced an episode of renal dysfunction after a median of 2 months (range, 1-10 months) following SCT. In all but one patient renal dysfunction was transient and resolved after a median of 8 months (range, 3-16 months). One single patient developed persistent renal dysfunction with onset at 10 months after SCT. None of these patients required dialysis. The actuarial 3-year freedom from persistent renal toxicity for children surviving > 12 months after SCt was 97.3%. Conclusion: the incidence of persistent renal dysfunction after fractionated TBI with total doses ≤ 12 Gy was very low in this analysis. (orig.)

  19. Preoperative chemoradiation for locally advanced rectal cancer: comparison of three radiation dose and fractionation schedules

    International Nuclear Information System (INIS)

    Park, Shin Hyung; Kim, Jae Chul

    2016-01-01

    The standard radiation dose for patients with locally rectal cancer treated with preoperative chemoradiotherapy is 45–50 Gy in 25–28 fractions. We aimed to assess whether a difference exists within this dose fractionation range. A retrospective analysis was performed to compare three dose fractionation schedules. Patients received 50 Gy in 25 fractions (group A), 50.4 Gy in 28 fractions (group B), or 45 Gy in 25 fractions (group C) to the whole pelvis, as well as concurrent 5-fluorouracil. Radical resection was scheduled for 8 weeks after concurrent chemoradiotherapy. Between September 2010 and August 2013, 175 patients were treated with preoperative chemoradiotherapy at our institution. Among those patients, 154 were eligible for analysis (55, 50, and 49 patients in groups A, B, and C, respectively). After the median follow-up period of 29 months (range, 5 to 48 months), no differences were found between the 3 groups regarding pathologic complete remission rate, tumor regression grade, treatment-related toxicity, 2-year locoregional recurrence-free survival, distant metastasis-free survival, disease-free survival, or overall survival. The circumferential resection margin width was a prognostic factor for 2-year locoregional recurrence-free survival, whereas ypN category was associated with distant metastasis-free survival, disease-free survival, and overall survival. High tumor regression grading score was correlated with 2-year distant metastasis-free survival and disease-free survival in univariate analysis. Three different radiation dose fractionation schedules, within the dose range recommended by the National Comprehensive Cancer Network, had no impact on pathologic tumor regression and early clinical outcome for locally advanced rectal cancer

  20. Preoperative chemoradiation for locally advanced rectal cancer: comparison of three radiation dose and fractionation schedules

    Energy Technology Data Exchange (ETDEWEB)

    Park, Shin Hyung; Kim, Jae Chul [Dept. of Radiation Oncology, Kyungpook National University School of Medicine, Daegu (Korea, Republic of)

    2016-06-15

    The standard radiation dose for patients with locally rectal cancer treated with preoperative chemoradiotherapy is 45–50 Gy in 25–28 fractions. We aimed to assess whether a difference exists within this dose fractionation range. A retrospective analysis was performed to compare three dose fractionation schedules. Patients received 50 Gy in 25 fractions (group A), 50.4 Gy in 28 fractions (group B), or 45 Gy in 25 fractions (group C) to the whole pelvis, as well as concurrent 5-fluorouracil. Radical resection was scheduled for 8 weeks after concurrent chemoradiotherapy. Between September 2010 and August 2013, 175 patients were treated with preoperative chemoradiotherapy at our institution. Among those patients, 154 were eligible for analysis (55, 50, and 49 patients in groups A, B, and C, respectively). After the median follow-up period of 29 months (range, 5 to 48 months), no differences were found between the 3 groups regarding pathologic complete remission rate, tumor regression grade, treatment-related toxicity, 2-year locoregional recurrence-free survival, distant metastasis-free survival, disease-free survival, or overall survival. The circumferential resection margin width was a prognostic factor for 2-year locoregional recurrence-free survival, whereas ypN category was associated with distant metastasis-free survival, disease-free survival, and overall survival. High tumor regression grading score was correlated with 2-year distant metastasis-free survival and disease-free survival in univariate analysis. Three different radiation dose fractionation schedules, within the dose range recommended by the National Comprehensive Cancer Network, had no impact on pathologic tumor regression and early clinical outcome for locally advanced rectal cancer.

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

    International Nuclear Information System (INIS)

    Serduc, Raphael; Braeuer-Krisch, Elke; Bouchet, Audrey; Brochard, Thierry; Bravin, Alberto; Le Duc, Geraldine; Renaud, Luc; Laissue, Jean Albert

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-15

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

  3. Modelling normal tissue isoeffect distribution in conformal radiotherapy of glioblastoma provides an alternative dose escalation pattern through hypofractionation without reducing the total dose

    International Nuclear Information System (INIS)

    Mangel, L.; Skriba, Z.; Major, T.; Polgar, C.; Fodor, J.; Somogyi, A.; Nemeth, G.

    2002-01-01

    The purpose of this study was to prove that by using conformal external beam radiotherapy (RT) normal brain structures can be protected even when applying an alternative approach of biological dose escalation: hypofractionation (HOF) without total dose reduction (TDR). Traditional 2-dimensional (2D) and conformal 3-dimensional (3D) treatment plans were prepared for 10 gliomas representing the subanatomical sites of the supratentorial brain. Isoeffect distributions were generated by the biologically effective dose (BED) formula to analyse the effect of conventionally fractionated (CF) and HOF schedules on both the spatial biological dose distribution and biological dose-volume histograms. A comparison was made between 2D-CF (2.0 Gy/day) and 3D-HOF (2.5 Gy/day) regimens, applying the same 60 Gy total doses. Integral biologically effective dose (IBED) and volumes received biologically equivalent to a dose of 54 Gy or more (V-BED54) were calculated for the lower and upper brain stem as organs of risk. The IBED values were lower with the 3D-HOF than with the 2D-CF schedule in each tumour location, means 22.7±17.1 and 40.4±16.9 in Gy, respectively (p<0.0001). The V-BED54 values were also smaller or equal in 90% of the cases favouring the 3D-HOF scheme. The means were 2.7±4.8 ccm for 3D-HOF and 10.7±12.7 ccm for 2D-CF (p=0.0006). Our results suggest that with conformal RT, fraction size can gradually be increased. HOF radiotherapy regimens without TDR shorten the treatment time and seem to be an alternative way of dose escalation in the treatment of glioblastoma

  4. Modelling normal tissue isoeffect distribution in conformal radiotherapy of glioblastoma provides an alternative dose escalation pattern through hypofractionation without reducing the total dose

    Energy Technology Data Exchange (ETDEWEB)

    Mangel, L.; Skriba, Z.; Major, T.; Polgar, C.; Fodor, J.; Somogyi, A.; Nemeth, G. [National Research Inst. for Radiobiology and Radiohygiene, Budapest (Hungary)

    2002-04-01

    The purpose of this study was to prove that by using conformal external beam radiotherapy (RT) normal brain structures can be protected even when applying an alternative approach of biological dose escalation: hypofractionation (HOF) without total dose reduction (TDR). Traditional 2-dimensional (2D) and conformal 3-dimensional (3D) treatment plans were prepared for 10 gliomas representing the subanatomical sites of the supratentorial brain. Isoeffect distributions were generated by the biologically effective dose (BED) formula to analyse the effect of conventionally fractionated (CF) and HOF schedules on both the spatial biological dose distribution and biological dose-volume histograms. A comparison was made between 2D-CF (2.0 Gy/day) and 3D-HOF (2.5 Gy/day) regimens, applying the same 60 Gy total doses. Integral biologically effective dose (IBED) and volumes received biologically equivalent to a dose of 54 Gy or more (V-BED54) were calculated for the lower and upper brain stem as organs of risk. The IBED values were lower with the 3D-HOF than with the 2D-CF schedule in each tumour location, means 22.7{+-}17.1 and 40.4{+-}16.9 in Gy, respectively (p<0.0001). The V-BED54 values were also smaller or equal in 90% of the cases favouring the 3D-HOF scheme. The means were 2.7{+-}4.8 ccm for 3D-HOF and 10.7{+-}12.7 ccm for 2D-CF (p=0.0006). Our results suggest that with conformal RT, fraction size can gradually be increased. HOF radiotherapy regimens without TDR shorten the treatment time and seem to be an alternative way of dose escalation in the treatment of glioblastoma.

  5. Chromium Fractions Changes Compared With Total-Cr As Determined by Neutron Activation Analysis Technique

    International Nuclear Information System (INIS)

    Abdel-Sabour, M.F.; Abdou, F.M.; Elwan, I.M.; Al-Salama, Y.J.

    2003-01-01

    Fifteen soil samples were chosen from different locations (five different locations at north greater Cairo, Egypt to represent different soils (alluvial and sandy) as well as different source of contaminated wastewater (sewage and industrial effluent). Using sequential extraction technique (extracting the soil with different solutions, which is designed to separate metal fractions), Cr was separated into six operationally defined fractions water soluble, exchangeable, carbonate bound, Fe-Mn oxides bound, organic bound and residual fractions. Result of soil total-Cr indicated the serious accumulation of Cr in soils subjected to prolonged irrigation with contaminated wastewater. As it could seen, total-Cr in the tested contaminated soils exceeds the permissible levels (75-100)ppm Cr by several order of magnitude particularly at the surface and subsurface layers. The highest accumulation of total Cr down to depth 60 cm was observed in case of soil E. Data showed that values of total Cr determined by NAA method were always higher than the relevant values determined either by AAS or those calculated after the sequential extraction method. T-test analysis showed the significant difference between NAA and either AAS or sequential extraction methods. Although T-test analysis showed that were significant differences between total content in soils as determined by destructive (AAS or SUM) and non-destructive (NAA) analytical techniques however, strong liner relation between NAA and other tested methods was obtained. Chromium distribution between different extractants shows that the greatest amounts are found in the residual and Occluded in Fe and Mn-Oxides fractions followed by carbonate or organic fractions. In most cases the proportion of all tested Cr-forms has increased in contaminated soil layers with higher enrichment in organically bound Cr, occluded in Fe and Mn oxides, carbonate exchangeable and soluble fractions. Results indicate that soil properties have a

  6. Effects of local single and fractionated X-ray doses on rat bone marrow blood flow and red blood cell volume

    International Nuclear Information System (INIS)

    Pitkaenen, M.A.; Hopewell, J.W.

    1985-01-01

    Time and dose dependent changes in blood flow and red blood cell volume were studied in the locally irradiated bone marrow of the rat femur after single and fractionated doses of X-rays. With the single dose of 10 Gy the bone marrow blood flow although initially reduced returned to the control levels by seven months after irradiation. With doses >=15 Gy the blood flow was still significantly reduced at seven months. The total dose levels predicted by the nominal standard dose equation for treatments in three, six or nine fractions produced approximately the same degree of reduction in the bone marrow blood flow seven months after the irradiation. However, the fall in the red blood cell volume was from 23 to 37% greater in the three fractions groups compared with that in the nine fractions groups. Using the red blood cell volume as a parameter the nominal standard dose formula underestimated the severity of radiation damage in rat bone marrow at seven months for irradiation with small numbers of large dose fractions. (orig.) [de

  7. Fractionation in medium dose rate brachytherapy of cancer of the cervix

    International Nuclear Information System (INIS)

    Leborgne, Felix; Fowler, Jack F.; Leborgne, Jose H.; Zubizarreta, Eduardo; Chappell, Rick

    1996-01-01

    Purpose: To establish an optimum fractionation for medium dose rate (MDR) brachytherapy from retrospective data of patients treated with different MDR schedules in comparison with a low dose rate (LDR) schedule. Methods and Materials: The study population consists of consecutive Stage IB-IIA-IIB patients who received radiotherapy alone with full dose brachytherapy plus external beam pelvic and parametrial irradiation from 1986-1993. Patients also receiving surgery or chemotherapy were excluded. The LDR group (n = 102, median follow-up: 80 months) received a median dose to Point A of two 32.5 Gy fractions at 0.44 Gy/h plus 18 Gy of external whole pelvic irradiation. The MDR1 group (n = 30, median follow-up: 45 months) received a mean dose of two 32 Gy fractions at 1.68 Gy/h. An individual dose reduction of 12.5% was planned for this group according to the Manchester experience, but only a 4.8% dose reduction was achieved. The MDR2 group (n = 10, median follow-up: 36 months) received a dose of two 24 Gy fractions at 1.65 Gy/h. The MDR3 group (n = 10, median follow-up 33 months) received a mean dose of three 15.3 Gy fractions at 1.64 Gy/h. And finally, the MDR4 group (n = 38, median follow-up: 24 months) received six 7.7 Gy fractions from two pulses 6 h apart in each of three insertions at 1.61 Gy/h. The median external pelvic dose to MDR schedules was between 12 and 20 Gy. The linear quadratic (LQ) formula was used to calculate the biologically effective dose (BED) to tumor (Gy 10 ) and rectum (Gy 3 ), assuming T(1(2)) for repair = 1.5 h. Results: The crude central recurrence rate was 6% for LDR (mean BED = 95.4 Gy 10 ) and 10% for MDR4 (mean BED = 77.0 Gy 10 ) (p = NS). The remaining MDR groups had no recurrences. Grade 2 and 3 rectal or bladder complications were 0% for LDR (rectal BED = 109 Gy 3 ), 83% for MDR1 (BED = 206 Gy 3 ), and 30% for MDR3 (BED = 127 Gy 3 ). The MDR2 and MDR4 groups presented no complications (BED, 123 Gy 3 , and 105 Gy 3 , respectively

  8. Clinical study on the adriamycin induced cardiomyopathy using the cardiac magnetic resonance imaging. Total dose and cardiac dysfunction

    International Nuclear Information System (INIS)

    Yamaguchi, Kyoko; Teraoka, Kunihiko; Hirano, Masaharu

    2001-01-01

    We studied cardiac functional disorders caused by Adoriamycin using gadolinium (Gd) contrast cine MRI. Forty-eight patients were given ACT (31 men and 17 women; mean age, 52±15 years). First, the relationship between dose and the left ventricular volume, cardiac function, left ventricular cardiac mass and localized wall motion were examined in all patients. Patients given a total dose of 300 mg/m 2 or higher were assigned to the high dose group and those given doses under 300 mg/m 2 to the low dose group. The same parameters were studied in both groups and compared. A 1.5-Tesla superconductive MRI was used for all studies. Cine images of the long and short axes at the papillary muscle level were obtained by ECG R-wave synchronized Gd contrast cine MRI. Left ventricular volume and cardiac function were analyzed using the long-axis cine images and the wall thickness in diastole and systole was measured at each site using the short-axis cine images. The percentage of wall thickness was calculated at each site. The mean ACT dose was 273.3±218.2 mg/m 2 . In all patients the total dose directly correlated with ESVI and inversely correlated with the ejection fraction (EF). In the high dose group, the total dose and EF were inversely correlated, but no significant differences were observed in the low dose group. In the high dose group, the ESVI was significantly greater and the SVI and EF were more significantly reduced than in the low dose group. In the high dose group, the thickness of the anterior, lateral and posterior walls, excluding the septum, was significantly lower than in the low dose group. However, changes in wall thickness were not significantly different between the groups. Gd contrast cine MRI was useful in examining cardiac functional disorders caused by anthracyclines. The total dose of anthracycline correlated directly with the ESVI, and inversely with the EF. A total dose of 300 mg/m 2 appeared to be the borderline dose beyond which there were

  9. Clinical study on the adriamycin induced cardiomyopathy using the cardiac magnetic resonance imaging. Total dose and cardiac dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Kyoko; Teraoka, Kunihiko; Hirano, Masaharu [Tokyo Medical Coll. (Japan)

    2001-05-01

    We studied cardiac functional disorders caused by Adoriamycin using gadolinium (Gd) contrast cine MRI. Forty-eight patients were given ACT (31 men and 17 women; mean age, 52{+-}15 years). First, the relationship between dose and the left ventricular volume, cardiac function, left ventricular cardiac mass and localized wall motion were examined in all patients. Patients given a total dose of 300 mg/m{sup 2} or higher were assigned to the high dose group and those given doses under 300 mg/m{sup 2} to the low dose group. The same parameters were studied in both groups and compared. A 1.5-Tesla superconductive MRI was used for all studies. Cine images of the long and short axes at the papillary muscle level were obtained by ECG R-wave synchronized Gd contrast cine MRI. Left ventricular volume and cardiac function were analyzed using the long-axis cine images and the wall thickness in diastole and systole was measured at each site using the short-axis cine images. The percentage of wall thickness was calculated at each site. The mean ACT dose was 273.3{+-}218.2 mg/m{sup 2}. In all patients the total dose directly correlated with ESVI and inversely correlated with the ejection fraction (EF). In the high dose group, the total dose and EF were inversely correlated, but no significant differences were observed in the low dose group. In the high dose group, the ESVI was significantly greater and the SVI and EF were more significantly reduced than in the low dose group. In the high dose group, the thickness of the anterior, lateral and posterior walls, excluding the septum, was significantly lower than in the low dose group. However, changes in wall thickness were not significantly different between the groups. Gd contrast cine MRI was useful in examining cardiac functional disorders caused by anthracyclines. The total dose of anthracycline correlated directly with the ESVI, and inversely with the EF. A total dose of 300 mg/m{sup 2} appeared to be the borderline dose beyond

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

    International Nuclear Information System (INIS)

    Douglas, B.G.

    1982-01-01

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

  11. Effect of the supply dose on the 15N enrichment level of cow's milk nitrogenous fractions

    International Nuclear Information System (INIS)

    Colin, O.; Laurent, F.; Vignon, B.; Antoine, J.M.

    1994-01-01

    Production of cow milk 15 N-labelled proteins is necessary for the study of their digestion by man. An adequate enrichment is required for compatibility with utilization constraints (application dose, studied fractions...). A test was conducted with five cows in order to optimize the utilization of labelled ammonium sulphate in the cow diet for 15 N enrichment of the milk nitrogenous matter. Doses and supply timing of labelled compounds are discussed. 3 figs., 3 refs

  12. 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

  13. ORGANIC CARBON AND TOTAL NITROGEN IN THE DENSIMETRIC FRACTIONS OF ORGANIC MATTER UNDER DIFFERENT SOIL MANAGEMEN

    Directory of Open Access Journals (Sweden)

    MARCELO RIBEIRO VILELA PRADO

    2016-01-01

    Full Text Available The evaluation of land use and management by the measurement of soil organic matter and its fractions has gained attention since it helps in the understanding of the dynamics of their contribution to soil productivity, especially in tropical environments. This study was conducted in the municipality of Colorado do Oeste, state of Rondônia, Brazil and its aim was to determinethe quantity of organic carbon and total nitrogen in the light and heavy fractions of organic matter in the surface layers of a typic hapludalf under different land use systems: Native Forest: open evergreen forest, reference environment; Agroforestry System 1: teak (Tectona grandis LF and kudzu (Pueraria montana; Agroforestry System 2: coffee (Coffea canephora, marandu palisade grass (Brachiaria brizantha cv. Marandu, “pinho cuiabano” (Parkia multijuga, teak and kudzu.; Agroforestry System 3: teak and cocoa (Theobroma cacao; Silvopasture System: teak, cocoa and marandu palisade grass; and Extensive Grazing System: marandu palisade grass. The experimental design was a randomized block in split-split plots (use systems versus soil layers of 0-0.05 and 0.05-0.10 m with three replications. The results showed that relative to Native Forest, the Agroforestry System 2 had equal- and greater amounts of organic carbon and total nitrogen respectively (light and heavy fractions in the soil organic matter, with the light fraction being responsible for storage of approximately 45% and 70% of the organic carbon and total nitrogen, respectively. Therefore, the light densimetric fraction proved to be useful in the early identification of the general decline of the soil organic matter in the land use systems evaluated.

  14. In vivo assessment of the gastric mucosal tolerance dose after single fraction, small volume irradiation of liver malignancies by computed tomography-guided, high-dose-rate brachytherapy

    International Nuclear Information System (INIS)

    Streitparth, Florian; Pech, Maciej; Boehmig, Michael; Ruehl, Ricarda; Peters, Nils; Wieners, Gero; Steinberg, Johannes; Lopez-Haenninen, Enrique; Felix, Roland; Wust, Peter; Ricke, Jens

    2006-01-01

    Purpose: The aim of this study was to assess the tolerance dose of gastric mucosa for single-fraction computed tomography (CT)-guided, high-dose-rate (HDR) brachytherapy of liver malignancies. Methods and Materials: A total of 33 patients treated by CT-guided HDR brachytherapy of liver malignancies in segments II and/or III were included. Dose planning was performed upon a three-dimensional CT data set acquired after percutaneous applicator positioning. All patients received gastric protection post-treatment. For further analysis, the contours of the gastric wall were defined in every CT slice using Brachyvision Software. Dose-volume histograms were calculated for each treatment and correlated with clinical data derived from questionnaires assessing Common Toxicity Criteria (CTC). All patients presenting symptoms of upper GI toxicity were examined endoscopically. Results: Summarizing all patients the minimum dose applied to 1 ml of the gastric wall (D 1ml ) ranged from 6.3 to 34.2 Gy; median, 14.3 Gy. Toxicity was present in 18 patients (55%). We found nausea in 16 (69%), emesis in 9 (27%), cramping in 13 (39%), weight loss in 12 (36%), gastritis in 4 (12%), and ulceration in 5 patients (15%). We found a threshold dose D 1ml of 11 Gy for general gastric toxicity and 15.5 Gy for gastric ulceration verified by an univariate analysis (p = 0.01). Conclusions: For a single fraction, small volume irradiation we found in the upper abdomen a threshold dose D 1ml of 15.5 Gy for the clinical endpoint ulceration of the gastric mucosa. This in vivo assessment is in accordance with previously published tolerance data

  15. Antidepressant effects of total tertiary alkaloid fraction of Cissampelos sympodialis Eichler in rodents

    Directory of Open Access Journals (Sweden)

    Sueli Mendonça-Netto

    Full Text Available The purpose of the present study was to evaluate the effects of total tertiary alkaloid fraction (TTAF of Cissampelos sympodialis Eichler (Menispermaceae on two animal models of depression: a forced swim test and b reserpine test. Treatment of mice with TTAF (12.5 mg/kg reduced the total immobility time. It also reversed the reserpine-induced hypothermia, demonstrating an antidepressant effect in both models. Additionally, TTAF treatment did not modify the ambulation and rearing evaluated in open field test in order to investigate if the immobility time reduction found in the forced swimming test was caused by locomotive activity stimulation. Since warifteine is one of the main alkaloids present in the TTAF of C. sympodialis, and it has inhibitory activity of the phosphodiesterase enzyme, it may be responsible by the antidepressant effect found in the fraction studied.

  16. Evaluation of accelerated test parameters for CMOS IC total dose hardness prediction

    International Nuclear Information System (INIS)

    Sogoyan, A.V.; Nikiforov, A.Y.; Chumakov, A.I.

    1999-01-01

    The approach to accelerated test parameters evaluation is presented in order to predict CMOS IC total dose behavior in variable dose-rate environment. The technique is based on the analytical model of MOSFET parameters total dose degradation. The simple way to estimate model parameter is proposed using IC's input-output MOSFET radiation test results. (authors)

  17. Universal Survival Curve and Single Fraction Equivalent Dose: Useful Tools in Understanding Potency of Ablative Radiotherapy

    International Nuclear Information System (INIS)

    Park, Clint; Papiez, Lech; Zhang Shichuan; Story, Michael; Timmerman, Robert D.

    2008-01-01

    Purpose: Overprediction of the potency and toxicity of high-dose ablative radiotherapy such as stereotactic body radiotherapy (SBRT) by the linear quadratic (LQ) model led to many clinicians' hesitating to adopt this efficacious and well-tolerated therapeutic option. The aim of this study was to offer an alternative method of analyzing the effect of SBRT by constructing a universal survival curve (USC) that provides superior approximation of the experimentally measured survival curves in the ablative, high-dose range without losing the strengths of the LQ model around the shoulder. Methods and Materials: The USC was constructed by hybridizing two classic radiobiologic models: the LQ model and the multitarget model. We have assumed that the LQ model gives a good description for conventionally fractionated radiotherapy (CFRT) for the dose to the shoulder. For ablative doses beyond the shoulder, the survival curve is better described as a straight line as predicted by the multitarget model. The USC smoothly interpolates from a parabola predicted by the LQ model to the terminal asymptote of the multitarget model in the high-dose region. From the USC, we derived two equivalence functions, the biologically effective dose and the single fraction equivalent dose for both CFRT and SBRT. Results: The validity of the USC was tested by using previously published parameters of the LQ and multitarget models for non-small-cell lung cancer cell lines. A comparison of the goodness-of-fit of the LQ and USC models was made to a high-dose survival curve of the H460 non-small-cell lung cancer cell line. Conclusion: The USC can be used to compare the dose fractionation schemes of both CFRT and SBRT. The USC provides an empirically and a clinically well-justified rationale for SBRT while preserving the strengths of the LQ model for CFRT

  18. Whole-body dose meters. Measurements of total activity

    International Nuclear Information System (INIS)

    Koeppe, P.; Klinikum Steglitz, Berlin

    1990-01-01

    By means of measurements using a whole-body dose meter, the course of the incorporation of radionuclides was established between April 1986 and May 1989 for unchanged conditions of alimentation, activity-conscious alimentation, and uniquely increased incorporation. Monitoring covered persons from the most different spheres of life. The incorporation is compared with the one resulting from nuclear weapons explosions in the atmosphere. (DG) [de

  19. Effect of action of fractioned ionizing radiation in small dose on thyroid gland of rats

    OpenAIRE

    О. О. Prykhodko; V. V. Lizogubov; V. S. Usenko

    2005-01-01

    The effect of fractionated X-irradiation by 0.25 Gy dose to rat thyroid gland was studied . It was shown the decrease of thyrocyte proliferative activity that can induce the late effect of pathogenesis to thyroid land and biochemical pathways that control by thyroid hormones. Additional effect by any mutagenic factor may induce thyroid tumor development.

  20. 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

  1. Dose fractionation effects in plateau-phase cultures of C3H 10T1/2 cells and their transformed counterparts

    International Nuclear Information System (INIS)

    Zeman, E.M.; Bedford, J.S.

    1985-01-01

    A comparison of γ-ray dose fractionation effects was made using plateau-phase cultures of C3H 10T1/2 cells and their transformed counterparts in an attempt to simulate basically similar populations of cells that differ primarily in their turnover rates. The status of cell populations with respect to their turnover rates may be an important factor influencing dose fractionation effects in early- and late-responding tissues. In this cell culture system, the rate of cell turnover was approximately three times higher for the plateau-phase transformed cultures. While the single acute dose survival curves for log-phase cells were indistinguishable, there were significant differences between the survival curves for plateau-phase cultures of the two cell types. Both cell lines had a similar capacity for repair of sublethal damage, but untransformed cells had a much greater capacity to repair potentially lethal damage in plateau phase. Multifraction survival curves were determined for both cell lines for doses per fraction ranging from 9.0 to 0.8 Gy, and from these isoeffect curves of log total dose versus dose per fraction were derived. The isoeffect curve for the slowly cycling, untransformed cells was found to be appreciably steeper than that for the more rapidly cycling transformed cells, a finding consistent with previously reported differences in dose fractionation isoeffect curves for early- and late-responding tissues in vivo

  2. Effective dose as an irritating influence during fractionated γ-irradiation

    International Nuclear Information System (INIS)

    Karpov, V.N.; Ushakov, I.B.; Davydov, B.I.

    1990-01-01

    The study of early neurological disturbances (END) in rats after fractionated γ-irradiation with doses of 37.5-225 Gy at dose rate of 30.11 Gy/min has demonstrated that the initial response of animals to pulse ionizing radiation is a function of the electric charge induced by ionizing radiation. A change in the probability of occurrence of each of the END symptoms, with the increased intervals between exposures, is merely an indirect indication of the eliminating mechanisms and is intricately connected with the irritating charge value. The proposed empiric relationships permit to correlate the probability of END symptom occurrence with the continuous quantitative parameter of fractionated irradiation, that is, with an effective dose as an analogue of the irritating effect

  3. Sterilization of boll weevil pupae with fractionated doses of gamma irradiation

    International Nuclear Information System (INIS)

    Haynes, J.W.; Mitlin, N.; Davich, T.B.; Dawson, J.R.; McGovern, W.L.; McKibben, G.H.

    1977-01-01

    Fractionated doses of 6,250-8,000 rads of gamma irradiation administered to pupae of the boll weevil, Anthonomus grandis Boh., sexually sterilized both sexes. Mortality of males thus treated with 6,250 and 8,000 rads via fractionation was 14% and 27% respectively, by 5 days posttreatment compared with 46% mortality when an equivalent acute dose was administered to newly emerged adults. Pheromone production of males irradiated at 6,250 rads was one-third that of the control for the first 4 days, but equal that of the control during 5-11 days posttreatment. This procedure lends itself to the large-scale sterilization of weevils needed in an eradication program. This technique is applicable to other insects that are highly susceptible to acute doses

  4. Fractionated dose cholecystography: a comparison between iopanoic acid and sodium ipodate

    Energy Technology Data Exchange (ETDEWEB)

    Reiner, R.G.; Lawson, M.J.; Davies, G.T.; Tucker, W.G.; Mileski, O.; Read, T.R.; Grant, A.K. (Queen Elizabeth Hospital, Adelaide (Australia))

    1980-11-01

    Two randomised groups of 100 subjects each, undergoing oral cholecystography, were given either a 6 g fractionated dose of iopanoic acid (Telepaque) or sodium ipodate (Biloptin) to determine the relative merits of this dose schedule. Exclusions to the study were pregnancy and iodine sensitivity. Calculi or abnormal gall-bladder opacification were present in 45% of subjects. Both agents were equally effective in demonstrating abnormalities, although bile duct visualisation was better using iopanoic acid (P<0.05). Of 46 subjects with abnormal cholecystograms subsequently undergoing surgery, all had the diagnosis confirmed. Side effects occurred in 63% of all subjects, being twice as common in those taking iopanoic acid (P<0.01). Sodium ipodate in a large fractionated dose is favoured because of the lower occurrence of side effects without loss of diagnostic accuracy.

  5. Fractionated dose cholecystography: a comparison between iopanoic acid and sodium ipodate

    International Nuclear Information System (INIS)

    Reiner, R.G.; Lawson, M.J.; Davies, G.T.; Tucker, W.G.; Mileski, O.; Read, T.R.; Grant, A.K.

    1980-01-01

    Two randomised groups of 100 subjects each, undergoing oral cholecystography, were given either a 6 g fractionated dose of iopanoic acid (Telepaque) or sodium ipodate (Biloptin) to determine the relative merits of this dose schedule. Exclusions to the study were pregnancy and iodine sensitivity. Calculi or abnormal gall-bladder opacification were present in 45% of subjects. Both agents were equally effective in demonstrating abnormalities, although bile duct visualisation was better using iopanoic acid (P<0.05). Of 46 subjects with abnormal cholecystograms subsequently undergoing surgery, all had the diagnosis confirmed. Side effects occurred in 63% of all subjects, being twice as common in those taking iopanoic acid (P<0.01). Sodium ipodate in a large fractionated dose is favoured because of the lower occurrence of side effects without loss of diagnostic accuracy. (author)

  6. Interstitial high-dose-rate brachytherapy boost: The feasibility and cosmetic outcome of a fractionated outpatient delivery scheme

    International Nuclear Information System (INIS)

    Manning, Matthew A.; Arthur, Douglas W.; Schmidt-Ullrich, Rupert K.; Arnfield, Mark R.; Amir, Cyrus; Zwicker, Robert D.

    2000-01-01

    Purpose: To evaluate the feasibility, potential toxicity, and cosmetic outcome of fractionated interstitial high dose rate (HDR) brachytherapy boost for the management of patients with breast cancer at increased risk for local recurrence. Methods and Materials: From 1994 to 1996, 18 women with early stage breast cancer underwent conventionally fractionated whole breast radiotherapy (50-50.4 Gy) followed by interstitial HDR brachytherapy boost. All were considered to be at high risk for local failure. Seventeen had pathologically confirmed final surgical margins of less than 2 mm or focally positive. Brachytherapy catheter placement and treatment delivery were conducted on an outpatient basis. Preplanning was used to determine optimal catheter positions to enhance dose homogeneity of dose delivery. The total HDR boost dose was 15 Gy delivered in 6 fractions of 2.5 Gy over 3 days. Local control, survival, late toxicities (LENT-SOMA), and cosmetic outcome were recorded in follow-up. In addition, factors potentially influencing cosmesis were analyzed by logistic regression analysis. Results: The minimum follow-up is 40 months with a median 50 months. Sixteen patients were alive without disease at last follow-up. There have been no in-breast failures observed. One patient died with brain metastases, and another died of unrelated causes without evidence of disease. Grade 1-2 late toxicities included 39% with hyperpigmentation, 56% with detectable fibrosis, 28% with occasional discomfort, and 11% with visible telangiectasias. Grade 3 toxicity was reported in one patient as persistent discomfort. Sixty-seven percent of patients were considered to have experienced good/excellent cosmetic outcomes. Factors with a direct relationship to adverse cosmetic outcome were extent of surgical defect (p = 0.00001), primary excision volume (p = 0.017), and total excision volume (p = 0.015). Conclusions: For high risk patients who may benefit from increased doses, interstitial HDR

  7. Total Skin Electron Beam Therapy in the Treatment of Mycosis Fungoides: A Review of Conventional and Low-Dose Regimens.

    Science.gov (United States)

    Chowdhary, Mudit; Chhabra, Arpit M; Kharod, Shivam; Marwaha, Gaurav

    2016-12-01

    Mycosis fungoides (MF) is the most prevalent subtype of cutaneous T-cell lymphoma, which is characterized by the proliferation of CD4 + T cells. While often an indolent disease, most patients eventually develop progression from isolated patches to tumors and finally nodal or visceral involvement. Treatment choice is largely based on disease burden, though prognostic factors such as disease stage, patient age, and extracutaneous involvement must be taken into consideration. Radiotherapy represents one of the most effective therapeutic modalities in the treatment of MF. Lymphocytes are exquisitely radiosensitive, and excellent responses are observed even with low doses of radiation. Total skin electron beam therapy (TSEBT) is a special technique that allows for the homogenous irradiation of the entire skin. There are well-documented radiation dose-response relationships for achieving a complete response. As such, TSEBT doses ≥ 30 Gy comprise the current standard of care. Although highly effective, most patients experience recurrent disease even after conventional-dose (≥ 30 Gy) TSEBT. In addition, toxicity is cumulatively dose dependent, and there is reluctance to administer multiple courses of conventional-dose TSEBT. Consequently, there has been renewed interest in determining the utility of TSEBT at lower total (≤ 30 Gy) doses. Advantages of low-total-dose (with standard dose per fraction) TSEBT include a shortened treatment course, the potential to minimize the risk of adverse events, and the opportunity to allow for retreatment in cases of disease recurrence. This comprehensive review compares the impact of different TSEBT dosing schemes on clinical outcomes of MF. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Induction by X-rays of chromosome aberrations in male guinea-pigs and golden hamsters. 4. Dose-response for spermatogonia treated with fractionated doses

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, M F; Cox, B D [Medical Research Council, Harwell (UK). Radiobiological Research Unit

    1975-10-01

    The effect of dose fractionation on the induction of translocations by 400 and 600 rad X-rays in spermatogonia of guinea-pigs and hamsters was investigated cytologically. Three types of fractionation were used, dividing the dose into (a) two equal fractions 24h apart, (b) two equal fractions 8 weeks apart, and (c) eight or twelve equal fractions of 50 rad, at intervals of one week. The two species responded similarly throughout, but gave lower translocation yields than the mouse. The effects of the first and third types of fractionation were similar to those described previously in the mouse, and suggested that a first radiation dose modifies the spermatogonial population so that its sensitivity to a dose 24h later is altered, and that repeated radiation doses result in development of resistance to translocation induction. After 8-week fractionation, the results suggested that in guinea-pigs and hamsters, the spermatogonial population had not returned to normal by 8 weeks after the first dose, whereas in the mouse, normal sensitivity had returned by this time. The results, reported previously, of single doses of X-rays suggest that the spermatogonial population consists of sub-populations differing in sensitivity to cell killing and genetic effects. The effects of fractionated doses in the mouse suggest that the sensitive and resistant types represent different phases of the samecell type rather than two distinct types of cell. In the guinea-pig and hamster, this question remains open.

  9. Comparison of the immunosuppressive effect of fractionated total lymphoid irradiation (TLI) vs conventional immunosuppression (CI) in renal cadaveric allotransplantation

    International Nuclear Information System (INIS)

    Waer, M.; Vanrenterghem, Y.; Ang, K.K.; van der Schueren, E.; Michielsen, P.; Vandeputte, M.

    1984-01-01

    Beginning in November 1981, eight patients with end stage diabetic nephropathy underwent renal cadaveric transplantation after TLI. Transplantation was done between 2 to 11 days after the end of a fractionated TLI to a total dose of 20 to 30 Gy. During the same observation period, 60 nondiabetic patients with end stage renal disease of different origin also received a cadaveric kidney graft, with a conventional regimen of immunosuppression that consists of anti-lymphocyte-globulin, tapering high doses of prednisone, and azathioprine. Phytohemagglutinin (PHA)-, concanavalin A (con A)-, and pokeweed mitogen (PWM)-induced blastogenesis, as well as the mixed lymphocyte reaction (MLR) and the cell-mediated lympholysis (CML) decreased progressively during the first months after conventional immunosuppression to 50% of the pretransplantation level, and remained there for the first year after transplantation. These tests were much more impaired after TLI and again no recovery occurred during the first year. In the clinic, the more profound immunosuppression in TLI patients was more frequently associated with viral infections (cytomegalovirus and herpes zoster). The incidence of rejections, however, was somewhat less frequent in the TLI-treated group and occurred significantly later. After TLI, the mean cumulative dose of steroids needed for kidney transplantation during the first year after transplantation could be substantially reduced

  10. Cytogenetic studies on recipients of allogeneic bone marrow transplants after fractionated total body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, N; Goedde-Salz, E; Loeffler, H [Christian-Albrechts-Univ., Kiel (Germany, F.R.)

    1985-06-01

    Cytogenetic findings from the bone marrow (BM) and the peripheral blood (PB) of nine consecutive patients after allogeneic bone marrow transplantation (BMT) for acute or chronic myelogenous leukaemia are reported. After a conditioning regimen consisting of cyclophosphamide and fractionated total body irradiation (TBI) given in five or six fractions of 2 Gy, persistence of host cells was detected in four out of seven cases with permanent engraftment. While one of these patients relapsed 4 months after host cells had been found in BM and PB, the other patients stayed relapse-free 124, 257 and 347 d after grafting. Before transplantation, the leukaemic cells in all three cases carried unique cytogenetic abnormalities giving the opportunity to distinguish the leukaemic population from chromosomally non-aberrant cells thought to represent residual normal host cells. As the persisting host cells after BMT lacked any cytogenetic abnormalities, it is suggested that they were members of residual normal clones not involved in the leukaemic process.

  11. Cytogenetic studies on recipients of allogeneic bone marrow transplants after fractionated total body irradiation

    International Nuclear Information System (INIS)

    Schmitz, N.; Goedde-Salz, E.; Loeffler, H.

    1985-01-01

    Cytogenetic findings from the bone marrow (BM) and the peripheral blood (PB) of nine consecutive patients after allogeneic bone marrow transplantation (BMT) for acute or chronic myelogenous leukaemia are reported. After a conditioning regimen consisting of cyclophosphamide and fractionated total body irradiation (TBI) given in five or six fractions of 2 Gy, persistence of host cells was detected in four out of seven cases with permanent engraftment. While one of these patients relapsed 4 months after host cells had been found in BM and PB, the other patients stayed relapse-free 124, 257 and 347 d after grafting. Before transplantation, the leukaemic cells in all three cases carried unique cytogenetic abnormalities giving the opportunity to distinguish the leukaemic population from chromosomally non-aberrant cells thought to represent residual normal host cells. As the persisting host cells after BMT lacked any cytogenetic abnormalities, it is suggested that they were members of residual normal clones not involved in the leukaemic process. (author)

  12. Fractional model for pharmacokinetics of high dose methotrexate in children with acute lymphoblastic leukaemia

    Science.gov (United States)

    Popović, Jovan K.; Spasić, Dragan T.; Tošić, Jela; Kolarović, Jovanka L.; Malti, Rachid; Mitić, Igor M.; Pilipović, Stevan; Atanacković, Teodor M.

    2015-05-01

    The aim of this study is to promote a model based on the fractional differential calculus related to the pharmacokinetic individualization of high dose methotrexate treatment in children with acute lymphoblastic leukaemia, especially in high risk patients. We applied two-compartment fractional model on 8 selected cases with the largest number (4-19) of measured concentrations, among 43 pediatric patients received 24-h methotrexate 2-5 g/m2 infusions. The plasma concentrations were determined by fluorescence polarization immunoassay. Our mathematical procedure, designed by combining Post's and Newton's method, was coded in Mathematica 8.0 and performed on Fujicu Celsius M470-2 PC. Experimental data show that most of the measured values of methotrexate were in decreasing order. However, in certain treatments local maximums were detected. On the other hand, integer order compartmental models do not give values which fit well with the observed data. By the use of our model, we obtained better results, since it gives more accurate behavior of the transmission, as well as the local maximums which were recognized in methotrexate monitoring. It follows from our method that an additional test with a small methotrexate dose can be suggested for the fractional system parameter identification and the prediction of a possible pattern with a full dose in the case of high risk patients. A special feature of the fractional model is that it can also recognize and better fit an observed non-monotonic behavior. A new parameter determination procedure can be successfully used.

  13. Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

    International Nuclear Information System (INIS)

    Trentham, D.E.; Belli, J.A.; Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

    1981-01-01

    Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly after a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered

  14. Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

    International Nuclear Information System (INIS)

    Trentham, D.E.; Belli, J.A.; Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

    1981-01-01

    Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly before a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered

  15. Compendium of Total Ionizing Dose and Displacement Damage for Candidate Spacecraft Electronics for NASA

    Science.gov (United States)

    Cochran, Donna J.; Boutte, Alvin J.; Chen, Dakai; Pellish, Jonathan A.; Ladbury, Raymond L.; Casey, Megan C.; Campola, Michael J.; Wilcox, Edward P.; Obryan, Martha V.; LaBel, Kenneth A.; hide

    2012-01-01

    Vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage is studied. Devices tested include optoelectronics, digital, analog, linear, and hybrid devices.

  16. Fractional poisson--a simple dose-response model for human norovirus.

    Science.gov (United States)

    Messner, Michael J; Berger, Philip; Nappier, Sharon P

    2014-10-01

    This study utilizes old and new Norovirus (NoV) human challenge data to model the dose-response relationship for human NoV infection. The combined data set is used to update estimates from a previously published beta-Poisson dose-response model that includes parameters for virus aggregation and for a beta-distribution that describes variable susceptibility among hosts. The quality of the beta-Poisson model is examined and a simpler model is proposed. The new model (fractional Poisson) characterizes hosts as either perfectly susceptible or perfectly immune, requiring a single parameter (the fraction of perfectly susceptible hosts) in place of the two-parameter beta-distribution. A second parameter is included to account for virus aggregation in the same fashion as it is added to the beta-Poisson model. Infection probability is simply the product of the probability of nonzero exposure (at least one virus or aggregate is ingested) and the fraction of susceptible hosts. The model is computationally simple and appears to be well suited to the data from the NoV human challenge studies. The model's deviance is similar to that of the beta-Poisson, but with one parameter, rather than two. As a result, the Akaike information criterion favors the fractional Poisson over the beta-Poisson model. At low, environmentally relevant exposure levels (Poisson model; however, caution is advised because no subjects were challenged at such a low dose. New low-dose data would be of great value to further clarify the NoV dose-response relationship and to support improved risk assessment for environmentally relevant exposures. © 2014 Society for Risk Analysis Published 2014. This article is a U.S. Government work and is in the public domain for the U.S.A.

  17. Effects of intra-fraction motion on IMRT dose delivery: statistical analysis and simulation

    International Nuclear Information System (INIS)

    Bortfeld, Thomas; Jokivarsi, Kimmo; Goitein, Michael; Kung, Jong; Jiang, Steve B.

    2002-01-01

    There has been some concern that organ motion, especially intra-fraction organ motion due to breathing, can negate the potential merit of intensity-modulated radiotherapy (IMRT). We wanted to find out whether this concern is justified. Specifically, we wanted to investigate whether IMRT delivery techniques with moving parts, e.g., with a multileaf collimator (MLC), are particularly sensitive to organ motion due to the interplay between organ motion and leaf motion. We also wanted to know if, and by how much, fractionation of the treatment can reduce the effects. We performed a statistical analysis and calculated the expected dose values and dose variances for volume elements of organs that move during the delivery of the IMRT. We looked at the overall influence of organ motion during the course of a fractionated treatment. A linear-quadratic model was used to consider fractionation effects. Furthermore, we developed software to simulate motion effects for IMRT delivery with an MLC, with compensators, and with a scanning beam. For the simulation we assumed a sinusoidal motion in an isocentric plane. We found that the expected dose value is independent of the treatment technique. It is just a weighted average over the path of motion of the dose distribution without motion. If the treatment is delivered in several fractions, the distribution of the dose around the expected value is close to a Gaussian. For a typical treatment with 30 fractions, the standard deviation is generally within 1% of the expected value for MLC delivery if one assumes a typical motion amplitude of 5 mm (1 cm peak to peak). The standard deviation is generally even smaller for the compensator but bigger for scanning beam delivery. For the latter it can be reduced through multiple deliveries ('paintings') of the same field. In conclusion, the main effect of organ motion in IMRT is an averaging of the dose distribution without motion over the path of the motion. This is the same as for treatments

  18. Influence of Exposure to Fractionated Dose of Gamma Radiation and Antioxidants Supplementation to Mice on program cell death induction

    International Nuclear Information System (INIS)

    Hanafi, A.

    2010-01-01

    The previous studies reported that the tumor suppressor protein (P53) is not functioning correctly in most human cancers, and that it plays a crucial role in the prevention of tumor development. This study was designed to evaluate if exposure to fractionated dose of gamma radiation impair function of P53 by the administration of antioxidants. Group of control mice was used. Another groups treated with 3 mg/mouse/day of Antox drug which contains the three main antioxidant vitamins (A, C, and E) together with trace element selenium for 15 days. Another group subjected to 1 Gy of gamma radiation 5 times every other day either alone or combined with the Antox drug supplementation. Hepatic and renal functions were evaluated. Antioxidant markers (MDA and GSH) levels, histopathological changes and P53 expression were recorded in liver and kidney tissues. Animals treated with Antox showed some increase in liver transaminases, non significant changes in total protein and albumin levels, a non significant change in kidney function profiles, a non significant increase in MDA and a significant increase in GSH levels in liver and kidney tissues. However, the exposure of mice to fractionated dose of gamma radiation led to a significant increase in kidney function profiles, AST and ALT activity, a significant decrease in total protein and albumin level, a significant increase in MDA levels and a significant decrease in GSH levels in liver and kidney were observed. Exposure of experimental animals post treatment with Antox drug to fractionated dose of gamma radiation revealed a significant amelioration in liver and kidney function profiles, a highly significant decrease in MDA levels and a significant increase in GSH level in comparison with irradiated group. Histopathological changes in liver and kidney recorded the same alterations observed with the biochemical parameters. P53 expression negatively expressed in normal liver and kidney tissues. However, the exposure of mice to

  19. Experience of micromultileaf collimator linear accelerator based single fraction stereotactic radiosurgery: Tumor dose inhomogeneity, conformity, and dose fall off

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Linda X.; Garg, Madhur; Lasala, Patrick; Kim, Mimi; Mah, Dennis; Chen, Chin-Cheng; Yaparpalvi, Ravindra; Mynampati, Dinesh; Kuo, Hsiang-Chi; Guha, Chandan; Kalnicki, Shalom [Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Neurosurgery, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Epidemiology and Population Health, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States)

    2011-03-15

    Purpose: Sharp dose fall off outside a tumor is essential for high dose single fraction stereotactic radiosurgery (SRS) plans. This study explores the relationship among tumor dose inhomogeneity, conformity, and dose fall off in normal tissues for micromultileaf collimator (mMLC) linear accelerator (LINAC) based cranial SRS plans. Methods: Between January 2007 and July 2009, 65 patients with single cranial lesions were treated with LINAC-based SRS. Among them, tumors had maximum diameters {<=}20 mm: 31; between 20 and 30 mm: 21; and >30 mm: 13. All patients were treated with 6 MV photons on a Trilogy linear accelerator (Varian Medical Systems, Palo Alto, CA) with a tertiary m3 high-resolution mMLC (Brainlab, Feldkirchen, Germany), using either noncoplanar conformal fixed fields or dynamic conformal arcs. The authors also created retrospective study plans with identical beam arrangement as the treated plan but with different tumor dose inhomogeneity by varying the beam margins around the planning target volume (PTV). All retrospective study plans were normalized so that the minimum PTV dose was the prescription dose (PD). Isocenter dose, mean PTV dose, RTOG conformity index (CI), RTOG homogeneity index (HI), dose gradient index R{sub 50}-R{sub 100} (defined as the difference between equivalent sphere radius of 50% isodose volume and prescription isodose volume), and normal tissue volume (as a ratio to PTV volume) receiving 50% prescription dose (NTV{sub 50}) were calculated. Results: HI was inversely related to the beam margins around the PTV. CI had a ''V'' shaped relationship with HI, reaching a minimum when HI was approximately 1.3. Isocenter dose and mean PTV dose (as percentage of PD) increased linearly with HI. R{sub 50}-R{sub 100} and NTV{sub 50} initially declined with HI and then reached a plateau when HI was approximately 1.3. These trends also held when tumors were grouped according to their maximum diameters. The smallest tumor group

  20. Dose mapping sensitivity to deformable registration uncertainties in fractionated radiotherapy – applied to prostate proton treatments

    International Nuclear Information System (INIS)

    Tilly, David; Tilly, Nina; Ahnesjö, Anders

    2013-01-01

    Calculation of accumulated dose in fractionated radiotherapy based on spatial mapping of the dose points generally requires deformable image registration (DIR). The accuracy of the accumulated dose thus depends heavily on the DIR quality. This motivates investigations of how the registration uncertainty influences dose planning objectives and treatment outcome predictions. A framework was developed where the dose mapping can be associated with a variable known uncertainty to simulate the DIR uncertainties in a clinical workflow. The framework enabled us to study the dependence of dose planning metrics, and the predicted treatment outcome, on the DIR uncertainty. The additional planning margin needed to compensate for the dose mapping uncertainties can also be determined. We applied the simulation framework to a hypofractionated proton treatment of the prostate using two different scanning beam spot sizes to also study the dose mapping sensitivity to penumbra widths. The planning parameter most sensitive to the DIR uncertainty was found to be the target D 95 . We found that the registration mean absolute error needs to be ≤0.20 cm to obtain an uncertainty better than 3% of the calculated D 95 for intermediate sized penumbras. Use of larger margins in constructing PTV from CTV relaxed the registration uncertainty requirements to the cost of increased dose burdens to the surrounding organs at risk. The DIR uncertainty requirements should be considered in an adaptive radiotherapy workflow since this uncertainty can have significant impact on the accumulated dose. The simulation framework enabled quantification of the accuracy requirement for DIR algorithms to provide satisfactory clinical accuracy in the accumulated dose

  1. The NARLAL2 dose escalation trial: dosimetric implications of inter-fractional changes in organs at risk

    DEFF Research Database (Denmark)

    Hoffmann, Lone; Knap, Marianne Marquard; Khalil, Azza Ahmed

    2018-01-01

    and an escalated treatment plan. In the escalated arm, mean doses up to 95 Gy/33 fractions (tumour) and 74 Gy/33 fractions (lymph nodes) are delivered to the most 18fluorodeoxyglucose-positron emission tomography (18FDG PET) active regions. The dose distributions are limited by strict constraints to OARs...

  2. Influence of radiation field and fractionation schedule of total lymphoid irradiation (TLI) on the induction of suppressor cells and stable chimerism after bone marrow transplantation in mice

    International Nuclear Information System (INIS)

    Waer, M.; Ang, K.K.; van der Schueren, E.; Vandeputte, M.

    1984-01-01

    When BALB/c mice received 17 daily fractions of 2 Gy each of total lymphoid irradiation (TLI, total dose 34 Gy) and 30 x 10 6 C 57 B1 bone marrow cells (BM) on the day after the last fraction, stable bone marrow chimerism without signs of graft-vs-host disease (GVHD) was obtained in 84% of the animals. On the contrary, in BALB/c mice receiving only seven fractions of TLI (total dose 14 Gy), all bone marrow grafts were rejected. When the last two fractions of a 14-Gy TLI course were given without shielding the extra lymphatic tissues (combined total lymphoid + total body irradiation, TLBI), chimerism could be induced in 53% of the animals. When this 14-Gy TLBI schedule was used, it was even possible to administer four fractions per day (multiple fractions per day schedule, MFD), thus reducing the overall treatment time to 2 consecutive days. After this concentrated form of TLBI, chimerism was detected in 35% of the animals. As in the 34-Gy TLI schedule, graft-vs-host reaction could not be prevented in the 14-Gy TLBI schedule when spleen lymphocytes (10 x 10 6 ) were added to the BM inocolum. Leucopenia or suppression of the phytohaemagglutinin (PHA)-induced blastogenesis could not predict which schedule would result in a successful allogeneic bone marrow take. Suppressor cells of the mixed lymphocyte reaction, on the other hand, were only found in the spleen of BALB/c mice treated with the TLI or TLBI schedules, which also resulted in stable bone marrow chimerism

  3. Daily fraction dose recalculation based on rigid registration using Cone Beam CT

    Directory of Open Access Journals (Sweden)

    Courtney Bosse

    2014-03-01

    Full Text Available Purpose: To calculate the daily fraction dose for CBCT recalculations based on rigid registration and compare it to the planned CT doses.Methods: For this study, 30 patients that were previously treated (10 SBRT lung, 10 prostate and 10 abdomen were considered. The daily CBCT images were imported into the Pinnacle treatment planning system from Mosaic. Pinnacle was used to re-contour the regions of interest (ROI for the specific CBCT by copying the contours from the original CT plan, planned by the prescribing physician, onto each daily CBCT and then manually reshaping contours to match the ROIs. A new plan is then created with the re-contoured CBCT as primary image in order to calculate the daily dose delivered to each ROI. The DVH values are then exported into Excel and overlaid onto the original CT DVH to produce a graph.Results: For the SBRT lung patients, we found that there were small daily volume changes in the lungs, trachea and esophagus. For almost all regions of interest we found that the dose received each day was less than the predicted dose of the planned CT while the PTV dose was relatively the same each day. The results for the prostate patients were similar, showing slight differences in the DVH values for different days in the rectum and bladder but similar PTV.Conclusion: By comparing daily fraction dose between the re-contoured CBCT images and the original planned CT show that PTV coverage for both prostate and SBRT, it has been shown that for PTV coverage, a planned CT is adequate. However, there are differences between the dose for the organs surrounding the PTV. The dose difference is less than the planned in most instances.-----------------------Cite this article as: Bosse C, Tuohy R, Mavroidis P, Shi Z, Crownover R, Gutierrez A, Papanikolaou N, Stathakis S. Daily fraction dose recalculation based on rigid registration using Cone Beam CT. Int J Cancer Ther Oncol 2014; 2(2:020217. DOI: 10.14319/ijcto.0202.17

  4. Response of rat spinal cord to single and fractionated doses of accelerated heavy ions

    International Nuclear Information System (INIS)

    Leith, J.T.; McDonald, M.; Powers-Risius, P.; Bliven, S.F.; Howard, J.

    1982-01-01

    The thoraco-lumbar (T12-L1) region of the spinal cord of rats was exposed to either single or fractionated (four daily exposures) doses of X rays (230 kVp) or heavy ions. The heavy ions used were carbon and neon, and the relative biological effectiveness (RBE) of both the plateau ionization region and the midpeak region of 4-cm spread-out Bragg peaks of each heavy ion were investigated. For single doses of carbon and neon ions in the plateau ionization region, RBE values of 1.45 +/- 0.25 (propagated 95% confidence limits) and 1.46 +/- 0.33, respectively, were obtained. In the spread peak regions for carbon and neon ions, the RBE values were 1.48 +/- 0.18 and 1.86 +/- 0.42, respectively. These values were obtained using the dose needed to produce 50% paralysis in a group of irradiated rats as the isoeffect comparison dose (ED 50 dose). Similarly, in groups of rats receiving four daily exposures, the RBE values for carbon and neon ions in the plateau ionization region were 1.31 +/- 0.27 and 1.80 +/- 0.24, respectively. In the spread peak regions of ionization for carbon and neon ions, the RBE values were 1.95 +/- 0.19 and 2.18 +/- 0.23, respectively. Similar values for RBE were obtained using changes in the activity of enzymes in spinal cord tissue (cyclic nucleotide phosphohydrolase and γ-glutamyl transpeptidase). Also, it was estimated that, for X irradiation, the fractional amount of dose repaired (at the ED 50 dose) was 0.64 +/- 0.10 (95% confidence limits). For carbon and neon ions in the plateau ionization region, the values for the fractional amount of dose repaired were 0.70 +/- 0.27 and 0.48 +/- 0.20, and for carbon and neon ions in the spread peak region of ionization, the fractional repair values were 0.40 +/- 0.10 and 0.52 +/- 0.17. Spinal cord tissue therefore shows a high capacity for subeffective damage repair

  5. Optimum radiotherapy schedule for uterine cervical cancer based-on the detailed information of dose fractionation and radiotherapy technique

    International Nuclear Information System (INIS)

    Cho, Jae Ho; Kim, Hyun Chang; Suh, Chang Ok

    2005-01-01

    The best dose-fractionation regimen of the definitive radiotherapy for cervix cancer remains to be clearly determined. It seems to be partially attributed to the complexity of the affecting factors and the lack of detailed information on external and intra-cavitary fractionation. To find optimal practice guidelines, our experiences of the combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) were reviewed with detailed information of the various treatment parameters obtained from a large cohort of women treated homogeneously at a single institute. The subjects were 743 cervical cancer patients (Stage IB 198, IIA 77, IIB 364, IIIA 7, IIIB 89 and IVA 8) treated by radiotherapy alone, between 1990 and 1996. A total external beam radiotherapy (EBRT) dose of 23.4 ∼ 59.4 Gy (Median 45.0) was delivered to the whole pelvis. High-dose-rate intracavitary brachytherapy (HDR-ICBT) was also performed using various fractionation schemes. A Midline block (MLB) was initiated after the delivery of 14.4∼ 43.2 Gy (Median 36.0) of EBRT in 495 patients, while in the other 248 patients EBRT could not be used due to slow tumor regression or the huge initial bulk of tumor. The point A, actual bladder and rectal doses were individually assessed in all patients. The biologically effective dose (BED) to the tumor (α / β = 10) and late-responding tissues (α /β = 3) for both EBRT and HDR-ICBT were calculated. The total BED values to point A, the actual bladder and rectal reference points were the summation of the EBRT and HDR-ICBT. In addition to all the details on dose-fractionation, the other factors (i.e. the overall treatment time, physicians preference) that can affect the schedule of the definitive radiotherapy were also thoroughly analyzed. The association between MD-BED Gy 3 and the risk of complication was assessed using serial multiple logistic regressions models. The associations between R-BED Gy 3 and rectal complications

  6. Dose fractionated gamma knife radiosurgery for large arteriovenous malformations on daily or alternate day schedule outside the linear quadratic model: Proof of concept and early results. A substitute to volume fractionation.

    Science.gov (United States)

    Mukherjee, Kanchan Kumar; Kumar, Narendra; Tripathi, Manjul; Oinam, Arun S; Ahuja, Chirag K; Dhandapani, Sivashanmugam; Kapoor, Rakesh; Ghoshal, Sushmita; Kaur, Rupinder; Bhatt, Sandeep

    2017-01-01

    To evaluate the feasibility, safety and efficacy of dose fractionated gamma knife radiosurgery (DFGKRS) on a daily schedule beyond the linear quadratic (LQ) model, for large volume arteriovenous malformations (AVMs). Between 2012-16, 14 patients of large AVMs (median volume 26.5 cc) unsuitable for surgery or embolization were treated in 2-3 of DFGKRS sessions. The Leksell G frame was kept in situ during the whole procedure. 86% (n = 12) patients had radiologic evidence of bleed, and 43% (n = 6) had presented with a history of seizures. 57% (n = 8) patients received a daily treatment for 3 days and 43% (n = 6) were on an alternate day (2 fractions) regimen. The marginal dose was split into 2 or 3 fractions of the ideal prescription dose of a single fraction of 23-25 Gy. The median follow up period was 35.6 months (8-57 months). In the three-fraction scheme, the marginal dose ranged from 8.9-11.5 Gy, while in the two-fraction scheme, the marginal dose ranged from 11.3-15 Gy at 50% per fraction. Headache (43%, n = 6) was the most common early postoperative complication, which was controlled with short course steroids. Follow up evaluation of at least three years was achieved in seven patients, who have shown complete nidus obliteration in 43% patients while the obliteration has been in the range of 50-99% in rest of the patients. Overall, there was a 67.8% reduction in the AVM volume at 3 years. Nidus obliteration at 3 years showed a significant rank order correlation with the cumulative prescription dose (p 0.95, P value 0.01), with attainment of near-total (more than 95%) obliteration rates beyond 29 Gy of the cumulative prescription dose. No patient receiving a cumulative prescription dose of less than 31 Gy had any severe adverse reaction. In co-variate adjusted ordinal regression, only the cumulative prescription dose had a significant correlation with common terminology criteria for adverse events (CTCAE) severity (P value 0.04), independent of age, AVM volume

  7. A novel technology coupling extraction and foam fractionation for separating the total saponins from Achyranthes bidentata.

    Science.gov (United States)

    Ding, Linlin; Wang, Yanji; Wu, Zhaoliang; Liu, Wei; Li, Rui; Wang, Yanyan

    2016-10-02

    A novel technology coupling extraction and foam fractionation was developed for separating the total saponins from Achyranthes bidentata. In the developed technology, the powder of A. bidentata was loaded in a nylon filter cloth pocket with bore diameter of 180 µm. The pocket was fixed in the bulk liquid phase for continuously releasing saponins. Under the optimal conditions, the concentration and the extraction rate of the total saponins in the foamate by the developed technology were 73.5% and 416.2% higher than those by the traditional technology, respectively. The foamates obtained by the traditional technology and the developed technology were analyzed by ultraperformance liquid chromatography-mass spectrometry to determine their ingredients, and the results appeared that the developed technology exhibited a better performance for separating saponins than the traditional technology. The study is expected to develop a novel technology for cost effectively separating plant-derived materials with surface activity.

  8. Intradermal Administration of Fractional Doses of Inactivated Poliovirus Vaccine: A Dose-Sparing Option for Polio Immunization.

    Science.gov (United States)

    Okayasu, Hiromasa; Sein, Carolyn; Chang Blanc, Diana; Gonzalez, Alejandro Ramirez; Zehrung, Darin; Jarrahian, Courtney; Macklin, Grace; Sutter, Roland W

    2017-07-01

    A fractional dose of inactivated poliovirus vaccine (fIPV) administered by the intradermal route delivers one fifth of the full vaccine dose administered by the intramuscular route and offers a potential dose-sparing strategy to stretch the limited global IPV supply while further improving population immunity. Multiple studies have assessed immunogenicity of intradermal fIPV compared with the full intramuscular dose and demonstrated encouraging results. Novel intradermal devices, including intradermal adapters and disposable-syringe jet injectors, have also been developed and evaluated as alternatives to traditional Bacillus Calmette-Guérin needles and syringes for the administration of fIPV. Initial experience in India, Pakistan, and Sri Lanka suggests that it is operationally feasible to implement fIPV vaccination on a large scale. Given the available scientific data and operational feasibility shown in early-adopter countries, countries are encouraged to consider introducing a fIPV strategy into their routine immunization and supplementary immunization activities. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  9. The influence of dose per fraction on the pathogenesis of radiation nephropathy

    Energy Technology Data Exchange (ETDEWEB)

    Yildiz, F.; Atahan, I.L.; Tuncel, M.; Konan, A. [Hacettepe University, Faculty of Medicine, Ankara (Turkey). Departments of Radiation Oncology and Anatomy

    1998-11-01

    Both kidneys of male Wistar rats were irradiated with either a 1 0-Gy single dose or 26 Gy at a rate of 2 Gy per fraction per day. Serum blood urea nitrogen (BUN), creatinine and blood haematocrit levels were assessed prior to radiotherapy and at intervals of 8 weeks thereafter. A subset of animals from each dose group were killed at 4, 8,16 and 24 weeks and both kidneys of each animal were examined by electron microscopy. In both dose groups a significant increase in BUN and creatinine levels, together with a decrease in haematocrit level, was observed at 16 weeks, and this was followed by an apparent improvement at 24 weeks. There was no statistical difference in these responses between the two groups. The morphological changes in both dose groups were essentially similar, but differed in severity. At 4 weeks after irradiation glomerular and proximal tubular injury were observed in both groups. A marked increase of glomerular and tubular injury in the 10-Gy dose group, without any apparent progression in the 26-Gy dose group, was detected at 8 weeks. By 16 weeks a noticeable improvement in both tubular and glomerular lesions (especially in the 10-Gy dose group) was observed. No apparent difference from the 16th week of evaluation was found at 24 weeks. These findings indicate that there is some recovery in kidney after irradiation, but the extent of the recovery process is somewhat limited. Copyright (1998) Blackwell Science Pty Ltd 38 refs., 1 tab., 4 figs.

  10. The HYP-RT Hypoxic Tumour Radiotherapy Algorithm and Accelerated Repopulation Dose per Fraction Study

    Directory of Open Access Journals (Sweden)

    W. M. Harriss-Phillips

    2012-01-01

    Full Text Available The HYP-RT model simulates hypoxic tumour growth for head and neck cancer as well as radiotherapy and the effects of accelerated repopulation and reoxygenation. This report outlines algorithm design, parameterisation and the impact of accelerated repopulation on the increase in dose/fraction needed to control the extra cell propagation during accelerated repopulation. Cell kill probabilities are based on Linear Quadratic theory, with oxygenation levels and proliferative capacity influencing cell death. Hypoxia is modelled through oxygen level allocation based on pO2 histograms. Accelerated repopulation is modelled by increasing the stem cell symmetrical division probability, while the process of reoxygenation utilises randomised pO2 increments to the cell population after each treatment fraction. Propagation of 108 tumour cells requires 5–30 minutes. Controlling the extra cell growth induced by accelerated repopulation requires a dose/fraction increase of 0.5–1.0 Gy, in agreement with published reports. The average reoxygenation pO2 increment of 3 mmHg per fraction results in full tumour reoxygenation after shrinkage to approximately 1 mm. HYP-RT is a computationally efficient model simulating tumour growth and radiotherapy, incorporating accelerated repopulation and reoxygenation. It may be used to explore cell kill outcomes during radiotherapy while varying key radiobiological and tumour specific parameters, such as the degree of hypoxia.

  11. Effect of Fractionated Low Doses of Gamma Radiation on Some Haematological and Immunological Parameters in Albino Rat

    International Nuclear Information System (INIS)

    Bahgat, M.M.; Abdel-Khalek, L.G.

    2003-01-01

    This study was performed on 30 mature male albino rats to evaluate the direct effect of fractionated low doses (0.5 Gy twice weekly) gamma radiation and delayed effect (one month post-irradiation) on some haematological and immunological parameters. The rats were divided into three equal groups, Control and two whole body gamma-irradiated groups the irradiated groups were subjected to total doses of 4 and 8 Grays over a period of one and two months, respectively. The blood samples and peritoneal macrophages were taken twice from each irradiated rats at the end of their irradiation period and after one month post irradiation. Activated peritoneal macrophages in all groups showed significant decrease as compared to control group denoting that irradiation may cause receptor alteration and/or decrease in the phagocytic power of macrophages lasting for a longer time. Throughout the whole experiment there was wide variation in platelet count with no significant or minimal changes in other blood elements. Moreover, in the post irradiation group after two months irradiation, all the haematological parameters tested, except the Hct, were increased as compared to the control group. These results pointed to that the bone marrow and lymphoid organs of the animals can tolerate fractionated low dose irradiation through rapid recovery and/or compensatory stimulation. The presence of many target cells in the post irradiated group increases the red blood cell fragility

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  13. Design of spray dried insulin microparticles to bypass deposition in the extrathoracic region and maximize total lung dose.

    Science.gov (United States)

    Ung, Keith T; Rao, Nagaraja; Weers, Jeffry G; Huang, Daniel; Chan, Hak-Kim

    2016-09-25

    Inhaled drugs all too often deliver only a fraction of the emitted dose to the target lung site due to deposition in the extrathoracic region (i.e., mouth and throat), which can lead to increased variation in lung exposure, and in some instances increases in local and systemic side effects. For aerosol medications, improved targeting to the lungs may be achieved by tailoring the micromeritic properties of the particles (e.g., size, density, rugosity) to minimize deposition in the mouth-throat and maximize the total lung dose. This study evaluated a co-solvent spray drying approach to modulate particle morphology and dose delivery characteristics of engineered powder formulations of insulin microparticles. The binary co-solvent system studied included water as the primary solvent mixed with an organic co-solvent, e.g., ethanol. Factors such as the relative rate of evaporation of each component of a binary co-solvent mixture, and insulin solubility in each component were considered in selecting feedstock compositions. A water-ethanol co-solvent mixture with a composition range considered suitable for modulating particle shell formation during drying was selected for experimental investigation. An Alberta Idealized Throat model was used to evaluate the in vitro total lung dose of a series of spray dried insulin formulations engineered with different bulk powder properties and delivered with two prototype inhalers that fluidize and disperse powder using different principles. The in vitro total lung dose of insulin microparticles was improved and favored for powders with low bulk density and small primary particle size, with reduction of deposition in the extrathoracic region. The results demonstrated that a total lung dose >95% of the delivered dose can be achieved with engineered particles, indicating a high degree of lung targeting, almost completely bypassing deposition in the mouth-throat. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Application of combined TLD and CR-39 PNTD method for measurement of total dose and dose equivalent on ISS

    International Nuclear Information System (INIS)

    Benton, E.R.; Deme, S.; Apathy, I.

    2006-01-01

    To date, no single passive detector has been found that measures dose equivalent from ionizing radiation exposure in low-Earth orbit. We have developed the I.S.S. Passive Dosimetry System (P.D.S.), utilizing a combination of TLD in the form of the self-contained Pille TLD system and stacks of CR-39 plastic nuclear track detector (P.N.T.D.) oriented in three mutually orthogonal directions, to measure total dose and dose equivalent aboard the International Space Station (I.S.S.). The Pille TLD system, consisting on an on board reader and a large number of Ca 2 SO 4 :Dy TLD cells, is used to measure absorbed dose. The Pille TLD cells are read out and annealed by the I.S.S. crew on orbit, such that dose information for any time period or condition, e.g. for E.V.A. or following a solar particle event, is immediately available. Near-tissue equivalent CR-39 P.N.T.D. provides Let spectrum, dose, and dose equivalent from charged particles of LET ∞ H 2 O ≥ 10 keV/μm, including the secondaries produced in interactions with high-energy neutrons. Dose information from CR-39 P.N.T.D. is used to correct the absorbed dose component ≥ 10 keV/μm measured in TLD to obtain total dose. Dose equivalent from CR-39 P.N.T.D. is combined with the dose component <10 keV/μm measured in TLD to obtain total dose equivalent. Dose rates ranging from 165 to 250 μGy/day and dose equivalent rates ranging from 340 to 450 μSv/day were measured aboard I.S.S. during the Expedition 2 mission in 2001. Results from the P.D.S. are consistent with those from other passive detectors tested as part of the ground-based I.C.C.H.I.B.A.N. intercomparison of space radiation dosimeters. (authors)

  15. Effect of single dose, fractionated, and hyperfractionated trunk irradiation on weight gain, respiration frequency, and survival in rats

    International Nuclear Information System (INIS)

    Kimler, B.F.; Giri, P.G.S.; Giri, U.P.; Cox, G.G.

    1986-01-01

    It is concluded that, in this rat trunk irradiation model, fractionation of a single dose into two equal doses separated by 4-6 h produced a sparing effect of approx. 5Gy as measured by delay in weight gain; approx. 4Gy as measured by increased respiration frequency; and approx. 6Gy as measured by survival. Fractionation into daily doses or hyperfractionation into twice-daily doses permitted an approximate doubling of the dose required for the same suppression of weight gain. For the respiration rates and survival endpoints, fractionation or hyperfractionation produced an even greater sparing effect since there was no increase in the respiration frequency at twice the doses that would produce changes if delivered within a few hours; and since essentially no lethality was observed at twice the doses that would kill 70%-100% of animals if delivered in one day. (UK)

  16. In vivo induction of apoptosis in human lymphocytes by therapeutic fractionated total body irradiation

    International Nuclear Information System (INIS)

    Delic, J.; Magdelenat, H.; Barbaroux, C.; Chaillet, M.-P.; Dubray, B.; Fourquet, A.; Cosset, J.-M.; Gluckman, E.; Girinsky, T.

    1995-01-01

    Ionizing radiations have been reported as an in vitro apoptosis initiating stimulus in human lymphocytes. As the cytotoxicity of ionizing radiations and chemotherapeutic agents appears to be dependent on the efficacy of cell death induction, the manipulation of apoptosis initiation might be used as a means to suppress some pathological process. In the present study the in vivo induction of γ-ray mediated programmed cell death in humans is reported. The in vivo induction of apoptosis in peripheral blood lymphocytes (PBL) by ionizing radiations was investigated in 33 patients after each of two sessions (2 Gy and 4 Gy) of fractionated total body irradiation (FTBI) as part of their conditioning regimen before bone marrow transplantation. PBL committed to apoptosis were scored before irradiation (S1), 4 h (S2) and 24 h after 2 Gy (S3, 14-17 h after the second 2 Gy fraction). Nuclear morphology and chromatin-DNA were analysed by fluorescence microscopy immediately after blood sample withdrawal (I) and after 24 h in cell culture medium (II). (author)

  17. Changes in the fraction of total hypoxia and hypoxia subtypes in human squamous cell carcinomas upon fractionated irradiation: Evaluation using pattern recognition in microcirculatory supply units

    International Nuclear Information System (INIS)

    Maftei, Constantin-Alin; Bayer, Christine; Shi, Kuangyu; Astner, Sabrina T.; Vaupel, Peter

    2011-01-01

    Background and purpose: Evaluate changes in total hypoxia and hypoxia subtypes in vital tumor tissue of human head and neck squamous cell carcinomas (hHNSCC) upon fractionated irradiation. Materials and methods: Xenograft tumors were generated from 5 hHNSCC cell lines (UT-SCC-15, FaDu, SAS, UT-SCC-5 and UT-SCC-14). Hypoxia subtypes were quantified in cryosections based on (immuno-)fluorescent marker distribution patterns of Hoechst 33342 (perfusion), pimonidazole (hypoxia) and CD31 (endothelium) in microcirculatory supply units (MCSUs). Tumors were irradiated with 5 or 10 fractions of 2 Gy, 5×/week. Results: Upon irradiation with 10 fractions, the overall fraction of hypoxic MCSUs decreased in UT-SCC-15, FaDu and SAS, remained the same in UT-SCC-5 and increased in UT-SCC-14. Decreases were observed in the proportion of chronically hypoxic MCSUs in UT-SCC-15, in the fraction of acutely hypoxic MCSUs in UT-SCC-15 and SAS, and in the percentage of hypoxemically hypoxic MCSUs in SAS tumors. After irradiation with 5 fractions, there were no significant changes in hypoxia subtypes. Changes in the overall fraction of hypoxic MCSUs were comparable to corresponding alterations in the proportions of acutely hypoxic MCSUs. There was no correlation between radiation resistance (TCD 50 ) and any of the investigated hypoxic fractions upon fractionated irradiation. Conclusions: This study shows that there are large alterations in the fractions of hypoxia subtypes upon irradiation that can differ from changes in the overall fraction of hypoxic MCSUs.

  18. Low-dose fractionated whole-body irradiation in the treatment of advanced non-Hodgkin's lymphoma

    International Nuclear Information System (INIS)

    Choi, N.C.; Timothy, A.R.; Kaufman, S.D.; Carey, R.W.; Aisenberg, A.C.

    1979-01-01

    Thirty-nine patients with advanced non-Hodgkin's lymphoma (38 patients with lymphocytic lymphoma and 1 patient with mixed lymphocytic and histiocytic lymphoma) were treated by fractionated low dose whole body irradiation (WBI) with a minimum follow-up of 8 months. Twenty-eight patients had no previous treatment and the other 11 patients were in relapse after previous chemotherapy or regional radiotherapy. There were 20 and 19 patients in stages III and IV groups, respectively. The majority of patients (31) had nodular histology; diffuse lymphocytic lymphoma was present in 8 patients (Rappaport criteria) (9). Constitutional symptoms were present in 10 patients. Thirty-three (85%) attained complete remission (CR) with median duration of remission 24 months. Actuarial survival was 78% and 74% at 3 and 4 years. However, relapse free survival was 26% at 3 and 4 years. A prospective randomized trial to compare 10 vs. 15 rad per fraction of fractionated WBI schedules (the same total dose 150 rad) demonstrated no difference in response rate, response duration, and median nadir platelet or WBC counts between the two schedules. Supplement radiotherapy to bulky tumor site prevented local recurrence, but did not influence survival or duration or remission. Major toxicity was thrombocytopenia with median nadir platelet counts 77,000/mm 3 (11,000 to 170,000/mm 3 ). Five of 6 patients with diffuse lymphocytic poorly differentiated lymphoma attained CR. However, their median survival was 30 months which is much shorter than that of nodular lymphoma. Constitutional symptoms and advanced stage (stage IV) were associated with shorter duration of remission. Response of patients in relapse after WBI to subsequent chemotherapy +- local radiotherapy was CR in 50% and PR in 40%. Fractionated whole body irradiation is an excellent systemic induction agent for advanced lymphocytic and mixed lymphoma

  19. Relationships between Personal Measurements of 'Total' Dust, Respirable, Thoracic, and Inhalable Aerosol Fractions in the Cement Production Industry.

    Science.gov (United States)

    Notø, Hilde P; Nordby, Karl-Christian; Eduard, Wijnand

    2016-05-01

    The aims of this study were to examine the relationships and establish conversion factors between 'total' dust, respirable, thoracic, and inhalable aerosol fractions measured by parallel personal sampling on workers from the production departments of cement plants. 'Total' dust in this study refers to aerosol sampled by the closed face 37-mm Millipore filter cassette. Side-by-side personal measurements of 'total' dust and respirable, thoracic, and inhalable aerosol fractions were performed on workers in 17 European and Turkish cement plants. Simple linear and mixed model regressions were used to model the associations between the samplers. The total number of personal samples collected on 141 workers was 512. Of these 8.4% were excluded leaving 469 for statistical analysis. The different aerosol fractions contained from 90 to 130 measurements and-side-by side measurements of all four aerosol fractions were collected on 72 workers.The median ratios between observed results of the respirable, 'total' dust, and inhalable fractions relative to the thoracic aerosol fractions were 0.51, 2.4, and 5.9 respectively. The ratios between the samplers were not constant over the measured concentration range and were best described by regression models. Job type, position of samplers on left or right shoulder and plant had no substantial effect on the ratios. The ratios between aerosol fractions changed with different air concentrations. Conversion models for estimation of the fractions were established. These models explained a high proportion of the variance (74-91%) indicating that they are useful for the estimation of concentrations based on measurements of a different aerosol fraction. The calculated uncertainties at most observed concentrations were below 30% which is acceptable for comparison with limit values (EN 482, 2012). The cement industry will therefore be able to predict the health related aerosol fractions from their former or future measurements of one of the

  20. The carcinogenic risk of high dose total body irradiation in non-human primates

    International Nuclear Information System (INIS)

    Broerse, J.J.; Bartstra, R.W.; Bekkum, D.W. van; Hage, M.H. van der; Zurcher, C.; Zwieten, M.J. van; Hollander, C.F.

    2000-01-01

    High dose total body irradiation (TBI) in combination with chemotherapy, followed by rescue with bone marrow transplantation (BMT), is increasingly used for the treatment of haematological malignancies. With the increasing success of this treatment and its current introduction for treating refractory autoimmune diseases the risk of radiation carcinogenesis is of growing concern. Studies on turnout induction in non-human primates are of relevance in this context since the response of this species to radiation does not differ much from that in man. Since the early sixties, studies have been performed on acute effects in Rhesus monkeys and the protective action of bone marrow transplantation after irradiation with X-rays (average total body dose 6.8 Gy) and fission neutrons (average dose 3.4 Gy). Of those monkeys, which were irradiated and reconstituted with autologous bone marrow, 20 animals in the X-irradiated group and nine animals in the neutron group survived more than 3 years. A group of 21 non-irradiated Rhesus monkeys of a comparable age distribution served as controls. All animals were regularly screened for the occurrence of neoplasms. Complete necropsies were performed after natural death or euthanasia. At post-irradiation intervals of 4-21 years an appreciable number of tumours was observed. In the neutron irradiated group eight out of nine animals died with one or more malignant tumours. In the X-irradiated group this fraction was 10 out of 20. The tumours in the control group, in seven out of the 21 animals, appeared at much older a-e compared with those in the irradiated cohorts. The histogenesis of the tumours was diverse with a preponderance of renal carcinoma, sarcomas among which osteosarcormas, and malignant glomus tumours in the irradiated groups. When corrected for competing risks, the carcinogenic risk of TBI in the Rhesus monkeys is similar to that derived from the studies of the Japanese atomic bomb survivors. The increase of the risk by a

  1. A framework to measure myocardial extracellular volume fraction using dual-phase low dose CT images

    International Nuclear Information System (INIS)

    Liu, Yixun; Summers, Ronald M.; Yao, Jianhua; Liu, Songtao; Sibley, Christopher T.; Bluemke, David A.; Nacif, Marcelo S.

    2013-01-01

    Purpose: Myocardial extracellular volume fraction (ECVF) is a surrogate imaging biomarker of diffuse myocardial fibrosis, a hallmark of pathologic ventricular remodeling. Low dose cardiac CT is emerging as a promising modality to detect diffuse interstitial myocardial fibrosis due to its fast acquisition and low radiation; however, the insufficient contrast in the low dose CT images poses great challenge to measure ECVF from the image. Methods: To deal with this difficulty, the authors present a complete ECVF measurement framework including a point-guided myocardial modeling, a deformable model-based myocardium segmentation, nonrigid registration of pre- and post-CT, and ECVF calculation. Results: The proposed method was evaluated on 20 patients by two observers. Compared to the manually delineated reference segmentations, the accuracy of our segmentation in terms of true positive volume fraction (TPVF), false positive volume fraction (FPVF), and average surface distance (ASD), were 92.18% ± 3.52%, 0.31% ± 0.10%, 0.69 ± 0.14 mm, respectively. The interobserver variability measured by concordance correlation coefficient regarding TPVF, FPVF, and ASD were 0.95, 0.90, 0.94, respectively, demonstrating excellent agreement. Bland-Altman method showed 95% limits of agreement between ECVF at CT and ECVF at MR. Conclusions: The proposed framework demonstrates its efficiency, accuracy, and noninvasiveness in ECVF measurement and dramatically advances the ECVF at cardiac CT toward its clinical use

  2. A framework to measure myocardial extracellular volume fraction using dual-phase low dose CT images

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yixun; Summers, Ronald M.; Yao, Jianhua, E-mail: JYao@cc.nih.gov [Clinical Image Processing Service, Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, Maryland 20892 (United States); Liu, Songtao; Sibley, Christopher T.; Bluemke, David A. [Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, Maryland 20892-1182 and Molecular Biomedical Imaging Laboratory, National Institute of Biomedical Imaging and Bioengineering, NIH Clinical Center, Bethesda, Maryland 20892 (United States); Nacif, Marcelo S. [Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, Maryland 20892-1182 (United States)

    2013-10-15

    Purpose: Myocardial extracellular volume fraction (ECVF) is a surrogate imaging biomarker of diffuse myocardial fibrosis, a hallmark of pathologic ventricular remodeling. Low dose cardiac CT is emerging as a promising modality to detect diffuse interstitial myocardial fibrosis due to its fast acquisition and low radiation; however, the insufficient contrast in the low dose CT images poses great challenge to measure ECVF from the image. Methods: To deal with this difficulty, the authors present a complete ECVF measurement framework including a point-guided myocardial modeling, a deformable model-based myocardium segmentation, nonrigid registration of pre- and post-CT, and ECVF calculation. Results: The proposed method was evaluated on 20 patients by two observers. Compared to the manually delineated reference segmentations, the accuracy of our segmentation in terms of true positive volume fraction (TPVF), false positive volume fraction (FPVF), and average surface distance (ASD), were 92.18% ± 3.52%, 0.31% ± 0.10%, 0.69 ± 0.14 mm, respectively. The interobserver variability measured by concordance correlation coefficient regarding TPVF, FPVF, and ASD were 0.95, 0.90, 0.94, respectively, demonstrating excellent agreement. Bland-Altman method showed 95% limits of agreement between ECVF at CT and ECVF at MR. Conclusions: The proposed framework demonstrates its efficiency, accuracy, and noninvasiveness in ECVF measurement and dramatically advances the ECVF at cardiac CT toward its clinical use.

  3. Impact of total ionizing dose on the electromagnetic susceptibility of a single bipolar transistor

    International Nuclear Information System (INIS)

    Doridant, A.; Jarrix, S.; Raoult, J.; Blain, A.; Dusseau, L.; Chatry, N.; Calvel, P.; Hoffmann, P.

    2012-01-01

    Space or military electronic components are subject to both electromagnetic fields and total ionizing dose. This paper deals with the electromagnetic susceptibility of a discrete low frequency transistor subject to total ionizing dose deposition. The electromagnetic susceptibility is investigated on both non-irradiated and irradiated transistors mounted in common emitter configuration. The change in susceptibility to 100 MHz-1.5 GHz interferences lights up a synergy effect between near field electromagnetic waves and total ionizing dose. Physical mechanisms leading to changes in signal output are detailed. (authors)

  4. Effect of fractionated X-ray doses on the hemogram and the protein formula of the mouse; Action de doses fractionnees de rayons X sur l'hemogramme et la formule proteique de la souris

    Energy Technology Data Exchange (ETDEWEB)

    Alix, D; Pierotti, Th [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-07-01

    The authors have studied the action of small doses of radiation on the system of mice. Irradiations was performed at doses of 50, 100, 150 or 200 R according to groups, either, as single dose or as fractionated doses. It was established that changes begin to become evident only after total exposure of 100 R. It occurs a decrease of cellular constituents and more often than not an increase of total proteins and {gamma}-globulins. (authors) [French] Les auteurs ont etudie l'action des faibles doses de radiation sur la souris. Des irradiations furent pratiquees a des doses totales de 50, 100, 150 ou 200 R suivant les lots, soit en dose unique, soit en doses fractionnees. Ils ont constate que les modifications ne commencent a apparaitre nettement qu'apres une exposition de 100 R au total. Elles se font dans le sens de la diminution pour les elements cellulaires, le plus souvent dans le sens de l'augmentation pour les proteines totales et les {gamma}-globulines. (auteurs)

  5. Low-dose fractionated percutaneous teletherapy in age-related macular degeneration with subfoveolar neovascularization - 3 year results

    International Nuclear Information System (INIS)

    Schittkowski, M.; Schneider, H.; Guthoff, R.; Grueschow, K.; Ziegler, P.G.; Fietkau, R.

    2001-01-01

    The effect of low dose fractionated percutaneous teletherapy to visual acuity and the changes in subfoveolar neovascular membranes in age-related macular degeneration were investigated. Patients and Method: 126 eyes of 118 patients (age 55-89 years; mean 74 ys.) were treated. Best distal and near visual acuity was assessed prior to (= initial visual acuity [IVA]) and 3, 6, 12, 18, 24, and 36 months after teletherapy. Fluorescein angiography was performed prior to and 6, 12, 24 and 36 months after radiation therapy. For analysis patients were divided into different groups by IVA and membrane size. Maximal duration of observation was 36 months. Teletherapy was done by a 9-MeV photon linear accelerator through a lateral port in half-beam technique with a single dose of 2 Gy up to a total dose of 20 Gy within 12 days. Results: No severe negative side effects have been observed. Eight patients reported of epiphora and four patients complained of transient sicca syndrome. Visual acuity decreased more than one line in the group IVA 0.05-0.2. The group IVA 0.3-0.5 remained unchanged for 1 year. We found a tendency for increased visual acuity in group IVA ≥ 0.6 for 18 months. After that time both groups showed decreased visual acuity, but all these patients reported of reduced metamorphopsia and increased color and contrast perception. Conclusions: There is an influence of low dose fractionated percutaneous teletherapy on visual acuity, subfoveal neovascular membranes and metamorphopsia. IVA and duration of anamnesis play an important role. There seems to be no persistent effect; possibly increased dosage will bring a benefit. (orig.) [de

  6. Gamma radiation-induced Impairment of hippocampal neurogenesis, comparison of single and fractionated dose regimens

    International Nuclear Information System (INIS)

    Khoshbin khoshnazar, A. R; Jahanshahi, M; Azami, N. S

    2012-01-01

    Radiation therapy of the brain is associated with many consequences, including cognitive disorders. Pathogenesis of radiation induced cognitive disorder is not clear, but reduction of neurogenesis in hippocampus may be an underlying reason. 24 adult male rats entered to study. Radiation absorbed dose to midbrain was 10 Gy, delivered by routine cobalt radiotherapy machine which its output was measured 115.24 cGy/min. The rats were divided in four groups of sixes, including groups of control, single fraction 10 Gy, fractionated 10 Gy and finally anaesthesia sham group. Number of pyramidal nerve cells was counted in two regions of hippocampus formation (CA1 and CA3). The radiation could reduce the number of cells in two regions of hippocampus significantly (p=0.000). It seems fractionated 10 Gy irradiation to more efficient than single fraction, while role of anaesthesia drug should be cautiously assessed. Moreover the rate of neurogenesis reduction was determined the same in these regions of hippocampus meaning the same radiosensitivity of cells

  7. Iodide-assisted total lead measurement and determination of different lead fractions in drinking water samples.

    Science.gov (United States)

    Zhang, Yuanyuan; Ng, Ding-Quan; Lin, Yi-Pin

    2012-07-01

    Lead and its compounds are toxic and can harm human health, especially the intelligence development in children. Accurate measurement of total lead present in drinking water is crucial in determining the extent of lead contamination and human exposure due to drinking water consumption. The USEPA method for total lead measurement (no. 200.8) is often used to analyze lead levels in drinking water. However, in the presence of high concentration of the tetravalent lead corrosion product PbO(2), the USEPA method was not able to fully recover particulate lead due to incomplete dissolution of PbO(2) particles during strong acid digestion. In this study, a new procedure that integrates membrane separation, iodometric PbO(2) measurement, strong acid digestion and ICP-MS measurement was proposed and evaluated for accurate total lead measurement and quantification of different lead fractions including soluble Pb(2+), particulate Pb(II) carbonate and PbO(2) in drinking water samples. The proposed procedure was evaluated using drinking water reconstituted with spiked Pb(2+), spiked particulate Pb(II) carbonate and in situ formed or spiked PbO(2). Recovery tests showed that the proposed procedure and the USEPA method can achieve 93-112% and 86-103% recoveries respectively for samples containing low PbO(2) concentrations (0.018-0.076 mg Pb per L). For samples containing higher concentrations of PbO(2) (0.089-1.316 mg Pb per L), the USEPA method failed to meet the recovery requirement for total lead (85-115%) while the proposed method can achieve satisfactory recoveries (91-111%) and differentiate the soluble Pb(2+), particulate Pb(II) carbonate and PbO(2).

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

    Science.gov (United States)

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

    2017-12-01

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

  9. Determination of the total indicative dose in drinking and mineral waters

    International Nuclear Information System (INIS)

    Flesch, K.; Schulz, H.; Knappik, R.; Koehler, M.

    2006-01-01

    In Europe and Germany administrative regulations exist for the surveillance of the total indicative dose of water supplied for human consumption. This parameter, which cannot be analyzed directly, has to be calculated using nuclide specific activity concentration and age specific dose conversion factors and consumption rates. Available calculation methods differ regarding the used radionuclides, consumption rates and whether they use age specific dose conversion factors or not. In Germany administrative guidelines for the determination of the total indicative dose are still not available. As they have analyzed a large number of waters in the past, the authors derive a praxis orientated concept for the determination of the total indicative dose which respects radiological, analytical and hydrochemical aspects as well. Finally it is suggested to handle sparkling waters in the same manner as drinking waters. (orig.)

  10. A comparison of anti-tumor effects of high dose rate fractionated and low dose rate continuous irradiation in multicellular spheroids

    International Nuclear Information System (INIS)

    Kubota, Nobuo; Omura, Motoko; Matsubara, Sho.

    1997-01-01

    In a clinical experience, high dose rate (HDR) fractionated interstitial radiotherapy can be an alternative to traditional low dose rate (LDR) continuous interstitial radiotherapy for head and neck cancers. To investigate biological effect of HDR, compared to LDR, comparisons have been made using spheroids of human squamous carcinoma cells. Both LDR and HDR were delivered by 137 Cs at 37degC. Dose rate of LDR was 8 Gy/day and HDR irradiations of fraction size of 4, 5 or 6 Gy were applied twice a day with an interval time of more than 6 hr. We estimated HDR fractionated dose of 31 Gy with 4 Gy/fr to give the same biological effects of 38 Gy by continuous LDR for spheroids. The ratio of HDR/LDR doses to control 50% spheroids was 0.82. (author)

  11. Lack of evidence for increased tolerance of rat spinal cord with decreasing fraction doses below 2 Gy

    International Nuclear Information System (INIS)

    Ang, K.K.; van der Kogel, A.J.; van der Schueren, E.

    1985-01-01

    The radiation tolerance of the spinal cord, both in man and in rats, has been shown to depend strongly on the size of the dose per fraction. With fraction doses down to about 2 Gy, the spinal cord tolerance can be predicted by a modified Ellis formula. More recently alternative isoeffect formulas were based on the linear-quadratic (LQ) model of cell survival where the effect of dose fractionation is characterized by the ratio α/β which varies from tissue to tissue. For the spinal cord, as well as for other late responding tissues, the ratio α/β is small, in contrast to most acutely responding tissues. Both the Ellis-type formula, and to a lesser extent the LQ-model, predict a continuously increasing tolerance dose with decreasing fraction size. From previous experiments on the rat cervical spinal cord with doses per fraction down to about 2 Gy, the ratio α/β was determined to be 1.7 Gy, and the LQ-model would predict a rise in tolerance with a reduction in fraction size to far below 2 Gy. Based on these predictions clinical studies have been initiated assuming a significantly increased tolerance by reduction of fraction size to about 1 Gy. However, in the present experiments no evidence was found for such an increase in tolerance with fraction sizes below 2 Gy

  12. Simulation of Shielding Effects on the Total Dose Observed in TDE of KISAT-1

    Directory of Open Access Journals (Sweden)

    Sung-Joon Kim

    2001-06-01

    Full Text Available The threshold voltage shift observed in TDE (Total Dose Experiment on board the KITSAT-1 is converted into dose (rad(SiO2 usinsg the result of laboratory calibration with Co-60 gamma ray source in KAERI (Korea Atomic Energy Research Institute. Simulation using the NASA radiation model of geomagnetosphere verifies that the dose difference between RADFET1 and RADFET3 observed on KITSAT-1 comes from the difference in shielding thickness at the position of these RADFETs.

  13. Effect of radiation dose rate and cyclophosphamide on pulmonary toxicity after total body irradiation in a mouse model

    International Nuclear Information System (INIS)

    Safwat, Akmal; Nielsen, Ole S.; El-Badawy, Samy; Overgaard, Jens

    1996-01-01

    Purpose: Interstitial pneumonitis (IP) is still a major complication after total body irradiation (TBI) and bone marrow transplantation (BMT). It is difficult to determine the exact role of radiation in this multifactorial complication, especially because most of the experimental work on lung damage was done using localized lung irradiation and not TBI. We have thus tested the effect of radiation dose rate and combining cyclophosphamide (CTX) with single fraction TBI on lung damage in a mouse model for BMT. Methods and Materials: TBI was given as a single fraction at a high dose rate (HDR, 0.71 Gy/min) or a low dose rate (LDR, 0.08 Gy/min). CTX (250 mg/kg) was given 24 h before TBI. Bone marrow transplantation (BMT) was performed 4-6 h after the last treatment. Lung damage was assessed using ventilation rate (VR) and lethality between 28 and 180 days (LD (50(28))-180 ). Results: The LD 50 for lung damage, ± standard error (SE), increased from 12.0 (± 0.2) Gy using single fraction HDR to 15.8 (± 0.6) Gy using LDR. Adding CTX shifted the dose-response curves towards lower doses. The LD 50 values for the combined treatment were 5.3 (± 0.2) and 3.5 (± 0.2) Gy for HDR and LDR, respectively. This indicates that the combined effect of CTX and LDR was more toxic than that of combined CTX and HDR. Lung damage evaluated by VR demonstrated two waves of VR increase. The first wave of VR increase occurred after 6 weeks using TBI only and after 3 weeks in the combined CTX-TBI treatment, irrespective of total dose or dose rate. The second wave of VR elevation resembled the IP that follows localized thoracic irradiation in its time of occurrence. Conclusions: Lung damage following TBI could be spared using LDR. However, CTX markedly enhances TBI-induced lung damage. The combination of CTX and LDR is more toxic to the lungs than combining CTX and HDR

  14. Dose rate effect from the relationship between ICRU rectal dose and local control rate in intracavitary radiotherapy for carcinoma of the uterine cervix. Six fraction HDR and three-fraction LDR in three weeks

    International Nuclear Information System (INIS)

    Jingu, Kenichi; Akita, Yuzou; Ohmagari, Jyunichi

    2001-01-01

    The dose rate effect, low dose rate radiotherapy (LDR)/high dose rate radiotherapy (HDR), was calculated using the isoeffect ICRU rectal dose by intracavitary radiotherapy (ICRT) for uterine cervix cancer. The subjects analyzed consisted of 78 LDR and 74 HDR patients whose ICRU rectal dose could be calculated and whose local control as stage II/III cases could be evaluated. The point A dose in ICRT was 45-55 Gy/3 fractions/3 weeks for LDR and 30 Gy/6 fractions/3 weeks for HDR. The dose effect relationships associated with local control at each whole pelvis external radiation dose were calculated using the double integration method and Probit analysis, and the 50% and 90% local control ICRU rectal doses were calculated from this relationship. Finally, the dose rate effect LDR/HDR was determined from 50% and 90% local control doses. The dose rate effect calculated from the 50% local control dose was 1.24 and that from the 90% local control dose was 1.14. (author)

  15. Extracranial doses during stereotactic radiosurgery and fractionated stereotactic radiotherapy measured with thermoluminescent dosimeter in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I.H.; Lim, D.H.; Kim, S.; Hong, S.; Kim, B.K.; Kang, W-S.; Wu, H.G.; Ha, S.W.; Park, C.I. [Seoul National University College of Medicine, Department of Therapeutic Radiology (Korea)

    2000-05-01

    Recently the usage of 3-dimensional non-coplanar radiotherapy technique is increasing. We measured the extracranial dose and its distribution g the above medical procedures to estimate effect of exit doses of stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) of the intracranial target lesions using a linac system developed in our hospital. Among over hundred patients who were treated with SRS or FSRT from 1995 to 1998, radiation dosimetry data of 15 cases with SRS and 20 cases with FSRT were analyzed. All patients were adults. Of SRS cases, 11 were male and 4 were female. Vascular malformation cases were 9, benign tumors were 3, and malignant tumors were 3. Of FSRT cases, males were 12 and females were 8. Primary malignant brain tumors were 5, benign tumors were 6, and metastatic brain tumors were 10. Doses were measured with lithium fluoride TLD chips (7.5% Li-6 and 92.5% Li-7; TLD-100, Harshaw/Filtrol, USA). The chips were attached patient's skin at the various extracranial locations during SRS or FSRT. For SRS, 14-25 Gy were delivered with 1-2 isocenters using 12-38 mm circular tertiary collimators with reference to 50-80% isodose line conforming at the periphery of the target lesions. For FSRT, 5-28 fractions were used to deliver 9-56 Gy to periphery with dose maximum of 10-66 Gy. Both procedures used 6 MV X-ray generated from Clinac-18 (Varian, USA). For SRS procedures, extracranial surface doses (relative doses) were 8.07{+-}4.27 Gy (0.31{+-}0.16% Mean{+-}S.D.) at the upper eyelids, 6.13{+-}4.32 Gy (0.24{+-}0.16%) at the submental jaw, 7.80{+-}5.44 Gy (0.33{+-}0.26%) at thyroid, 1.78{+-}0.64 Gy (0.07{+-}0.02%) at breast, 0.75{+-}0.38 Gy (0.03{+-}0.02%) at umbilicus, 0.40{+-}0.07 Gy (0.02{+-}0.01%) at perineum, and 0.46{+-}0.39 Gy (0.02{+-}0.01%) at scrotum. Thus the farther the distance from the brain, the less the dose to the location. In overall the doses were less than 0.3% and thus less detrimental. For FSRT procedures

  16. Effect of γ-dose rate and total dose interrelation on the polymeric hydrogel: A novel injectable male contraceptive

    International Nuclear Information System (INIS)

    Jha, Pradeep K.; Jha, Rakhi; Gupta, B.L.; Guha, Sujoy K.

    2010-01-01

    Functional necessity to use a particular range of dose rate and total dose of γ-initiated polymerization to manufacture a novel polymeric hydrogel RISUG (reversible inhibition of sperm under guidance) made of styrene maleic anhydride (SMA) dissolved in dimethyl sulphoxide (DMSO), for its broad biomedical application explores new dimension of research. The present work involves 16 irradiated samples. They were tested by fourier transform infrared spectroscopy, matrix assisted laser desorption/ionization-TOF, field emission scanning electron microscopy, high resolution transmission electron microscopy, etc. to see the interrelation effect of gamma dose rates (8.25, 17.29, 20.01 and 25.00 Gy/min) and four sets of doses (1.8, 2.0, 2.2 and 2.4 kGy) on the molecular weight, molecular weight distribution and porosity analysis of the biopolymeric drug RISUG. The results of randomized experiment indicated that a range of 18-24 Gy/min γ-dose rate and 2.0-2.4 kGy γ-total doses is suitable for the desirable in vivo performance of the contraceptive copolymer.

  17. An In Silico Approach for Evaluating a Fraction-Based, Risk Assessment Method for Total Petroleum Hydrocarbon Mixtures

    Directory of Open Access Journals (Sweden)

    Nina Ching Y. Wang

    2012-01-01

    Full Text Available Both the Massachusetts Department of Environmental Protection (MADEP and the Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG developed fraction-based approaches for assessing human health risks posed by total petroleum hydrocarbon (TPH mixtures in the environment. Both organizations defined TPH fractions based on their expected environmental fate and by analytical chemical methods. They derived toxicity values for selected compounds within each fraction and used these as surrogates to assess hazard or risk of exposure to the whole fractions. Membership in a TPH fraction is generally defined by the number of carbon atoms in a compound and by a compound's equivalent carbon (EC number index, which can predict its environmental fate. Here, we systematically and objectively re-evaluate the assignment of TPH to specific fractions using comparative molecular field analysis and hierarchical clustering. The approach is transparent and reproducible, reducing inherent reliance on judgment when toxicity information is limited. Our evaluation of membership in these fractions is highly consistent (̃80% on average across various fractions with the empirical approach of MADEP and TPHCWG. Furthermore, the results support the general methodology of mixture risk assessment to assess both cancer and noncancer risk values after the application of fractionation.

  18. Characterization of Radiation Hardened Bipolar Linear Devices for High Total Dose Missions

    Science.gov (United States)

    McClure, Steven S.; Harris, Richard D.; Rax, Bernard G.; Thorbourn, Dennis O.

    2012-01-01

    Radiation hardened linear devices are characterized for performance in combined total dose and displacement damage environments for a mission scenario with a high radiation level. Performance at low and high dose rate for both biased and unbiased conditions is compared and the impact to hardness assurance methodology is discussed.

  19. Arsenic speciation in total contents and bioaccessible fractions in atmospheric particles related to human intakes

    International Nuclear Information System (INIS)

    Huang, Minjuan; Chen, Xunwen; Zhao, Yinge; Yu Chan, Chuen; Wang, Wei; Wang, Xuemei; Wong, Ming Hung

    2014-01-01

    Speciation of inorganic trivalent arsenicals (iAs III ), inorganic pentavalent arsenicals (iAs V ), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in total arsenic (As) content and its bioaccessible fractions contained in road dust, household air-conditioning (AC) filter dust and PM 2.5 was investigated. Inorganic As, especially iAs V , was observed as the dominant species. Physiologically based extraction test (PBET), an in-vitro gastrointestinal method, was used to estimate the oral As bioaccessibility in coarse particles and the species present in the oral bioaccessible fraction. A composite lung simulating serum was used to mimic the pulmonary condition to extract the respiratory bioaccessible As and its species in PM 2.5 . Reduction of iAs V to iAs III occurred in both in-vitro gastrointestinal and lung simulating extraction models. The inorganic As species was the exclusive species for absorption through ingestion and inhalation of atmospheric particles, which was an important exposure route to inorganic As, in addition to drinking water and food consumption. - Highlights: • Inorganic As species was the predominant species in dust and airborne particles. • Existence of iAs III in dust and airborne particles increases human health risks. • Reduction from iAs V to iAs III occurred through in-vitro gastrointestinal model. • Reduction from iAs V to iAs III occurred in the simulating pulmonary region. • Atmospheric particles were important exposure sources of inorganic As. - Atmospheric particles are important exposure sources of inorganic As, of which the bioaccessibility is dependent on the extraction phases and models used

  20. Compendium of Current Total Ionizing Dose and Displacement Damage Results from NASA GSFC and NEPP

    Science.gov (United States)

    Topper, Alyson D.; Campola, Michael J.; Chen, Dakai; Casey, Megan C.; Yau, Ka-Yen; Label, Kenneth A.; Cochran, Donna J.; O'Bryan, Martha V.

    2017-01-01

    Total ionizing dose and displacement damage testing was performed to characterize and determine the suitability of candidate electronics for NASA space utilization. Devices tested include opto-electronics, digital, analog, linear bipolar devices, and hybrid devices.

  1. Recent Total Ionizing Dose and Displacement Damage Compendium of Candidate Electronics for NASA Space Systems

    Science.gov (United States)

    Cochran, Donna J.; Boutte, Alvin J.; Campola, Michael J.; Carts, Martin A.; Casey, Megan C.; Chen, Dakai; LaBel, Kenneth A.; Ladbury, Raymond L.; Lauenstein, Jean-Marie; Marshall, Cheryl J.; hide

    2011-01-01

    Vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage is studied. Devices tested include optoelectronics, digital, analog, linear bipolar devices, and hybrid devices.

  2. The Role of Electron Transport and Trapping in MOS Total-Dose Modeling

    International Nuclear Information System (INIS)

    Flament, O.; Fleetwood, D.M.; Leray, J.L.; Paillet, P.; Riewe, L.C.; Winokur, P.S.

    1999-01-01

    Deep and shallow electron traps form in irradiated thermal SiO 2 as a natural response to hole transport and trapping. The density and stability of these defects are discussed, as are their implications for total-dose modeling

  3. Total dose effects on the matching properties of deep submicron MOS transistors

    International Nuclear Information System (INIS)

    Wang Yuxin; Hu Rongbin; Li Ruzhang; Chen Guangbing; Fu Dongbing; Lu Wu

    2014-01-01

    Based on 0.18 μm MOS transistors, for the first time, the total dose effects on the matching properties of deep submicron MOS transistors are studied. The experimental results show that the total dose radiation magnifies the mismatch among identically designed MOS transistors. In our experiments, as the radiation total dose rises to 200 krad, the threshold voltage and drain current mismatch percentages of NMOS transistors increase from 0.55% and 1.4% before radiation to 17.4% and 13.5% after radiation, respectively. PMOS transistors seem to be resistant to radiation damage. For all the range of radiation total dose, the threshold voltage and drain current mismatch percentages of PMOS transistors keep under 0.5% and 2.72%, respectively. (semiconductor devices)

  4. Analysis of Surface Dose Refer to Distance between Beam Spoiler and Patient in Total Body Irradiation

    International Nuclear Information System (INIS)

    Choi, Jong Hwan; Kim, Jong Sik; Choi, Ji Min; Shin, Eun Hyuk; Song, Ki Won; Park, Young Hwan

    2007-01-01

    Total body irradiation is used to kill the total malignant cell and for immunosuppression component of preparatory regimens for bone-marrow restitution of patients. Beam spoiler is used to increase the dose to the superficial tissues. This paper finds the property of the distance between beam spoiler and patient. Set-up conditions are 6 MV-Xray, 300 MU, SAD = 400 cm, field size = 40 x 40 cm 2 . The parallel plate chamber located in surface, midpoint and exit of solid water phantom. The surface dose is measured while the distance between beam spoiler and patient is altered. Because it should be found proper distance. The solid water phantom is fixer and beam spoiler is moving. Central dose of phantom is 10.7 cGy and exit dose is 6.7 cGy. In case of distance of 50 cm to 60 cm between beam spoiler and solid water phantom, incidence dose is 14.58-14.92 cGy. Therefore, The surface dose was measured 99.4-101% with got near most to the prescription dose. In clinical case, distance between beam spoiler and patient affect surface dose. If once 50-60 cm of distance between beam spoiler and patient, surface dose of patient got near prescription dose. It would be taken distance between beam spoiler and patient into account in clinical therapy.

  5. Radiation therapy in cancer patients with psoriasis. The fractionated daily dose and the Koebner phenomenon

    International Nuclear Information System (INIS)

    Ben-Yosef, Rami; Soyfer, Vyacheslav; Vexler, Akiva

    2005-01-01

    Skin side effects following XRT take place more often in patients with skin disorders. In this study six patients with psoriatic lesions were evaluated. The total/daily XRT dose to the tumor site was 50-70/1.8-2.0 Gy. No debilitating effect of XRT was observed in both the psoriatic lesions and in the surrounding normal skin

  6. Estimation of the dose distribution within, and total dose to, the body of an acutely overexposed person

    International Nuclear Information System (INIS)

    Beer, G.P. de; Feather, J.I.; Oude, A. de; Language, A.E.

    1981-01-01

    In a case of accidental overexposure of a person, it is important to obtain a reliable value of the whole body dose as well as of the dose distribution within the body. Any follow-up treatment based only on the clinical effects as and when they appear, may result in insufficient or even erroneous therapy. In this respect knowledge of total dose and its distribution within the body may be a valuable aid in deciding on the follow-up treatment, taking into account the latent nature of the clinical effects. The calculated whole body dose and its distribution within the body of a person overexposed to a 192 Ir radiography source, are compared to experimentally determined values. In both cases the calculated values prove to be of sufficient accuracy to serve as an aid in decisions on the follow-up treatment. (author)

  7. Five-Year Outcomes of High-Dose Single-Fraction Spinal Stereotactic Radiosurgery

    International Nuclear Information System (INIS)

    Moussazadeh, Nelson; Lis, Eric; Katsoulakis, Evangelia; Kahn, Sweena; Svoboda, Marek; DiStefano, Natalie M.; McLaughlin, Lily; Bilsky, Mark H.; Yamada, Yoshiya; Laufer, Ilya

    2015-01-01

    Purpose: To characterize local tumor control and toxicity risk in very long-term survivors (>5 years) after high-dose spinal image guided, intensity modulated radiation therapy delivered as single-dose stereotactic radiosurgery (SRS). Previously published spinal SRS outcome analyses have included a heterogeneous population of cancer patients, mostly with short survival. This is the first study reporting the long-term tumor control and toxicity profiles after high-dose single-fraction spinal SRS. Methods and Materials: The study population included all patients treated from June 2004 to July 2009 with single-fraction spinal SRS (dose 24 Gy) who had survived at least 5 years after treatment. The endpoints examined included disease progression, surgical or radiation retreatment, in-field fracture development, and radiation-associated toxicity, scored using the Radiation Therapy Oncology Group radiation morbidity scoring criteria and the Common Terminology Criteria for Adverse Events, version 4.0. Local control and fracture development were assessed using Kaplan-Meier analysis. Results: Of 278 patients, 31 (11.1%), with 36 segments treated for spinal tumors, survived at least 5 years after treatment and were followed up radiographically and clinically for a median of 6.1 years (maximum 102 months). The histopathologic findings for the 5-year survivors included radiation-resistant metastases in 58%, radiation-sensitive metastases in 22%, and primary bone tumors in 19%. In this selected cohort, 3 treatment failures occurred at a median of 48.6 months, including 2 recurrences in the radiation field and 1 patient with demonstrated progression at the treatment margins. Ten lesions (27.8%) were associated with acute grade 1 cutaneous or gastrointestinal toxicity. Delayed toxicity ≥3 months after treatment included 8 cases (22.2%) of mild neuropathy, 2 (5.6%) of gastrointestinal discomfort, 8 (22.2%) of dermatitides, and 3 (8.3%) of myalgias/myositis. Thirteen

  8. Five-Year Outcomes of High-Dose Single-Fraction Spinal Stereotactic Radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Moussazadeh, Nelson [Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York (United States); Lis, Eric [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Katsoulakis, Evangelia [Department of Radiation Oncology, New York Methodist Hospital, Brooklyn, New York (United States); Kahn, Sweena; Svoboda, Marek; DiStefano, Natalie M.; McLaughlin, Lily [Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Bilsky, Mark H. [Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York (United States); Yamada, Yoshiya [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Laufer, Ilya, E-mail: lauferi@mskcc.org [Division of Neurological Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York (United States)

    2015-10-01

    Purpose: To characterize local tumor control and toxicity risk in very long-term survivors (>5 years) after high-dose spinal image guided, intensity modulated radiation therapy delivered as single-dose stereotactic radiosurgery (SRS). Previously published spinal SRS outcome analyses have included a heterogeneous population of cancer patients, mostly with short survival. This is the first study reporting the long-term tumor control and toxicity profiles after high-dose single-fraction spinal SRS. Methods and Materials: The study population included all patients treated from June 2004 to July 2009 with single-fraction spinal SRS (dose 24 Gy) who had survived at least 5 years after treatment. The endpoints examined included disease progression, surgical or radiation retreatment, in-field fracture development, and radiation-associated toxicity, scored using the Radiation Therapy Oncology Group radiation morbidity scoring criteria and the Common Terminology Criteria for Adverse Events, version 4.0. Local control and fracture development were assessed using Kaplan-Meier analysis. Results: Of 278 patients, 31 (11.1%), with 36 segments treated for spinal tumors, survived at least 5 years after treatment and were followed up radiographically and clinically for a median of 6.1 years (maximum 102 months). The histopathologic findings for the 5-year survivors included radiation-resistant metastases in 58%, radiation-sensitive metastases in 22%, and primary bone tumors in 19%. In this selected cohort, 3 treatment failures occurred at a median of 48.6 months, including 2 recurrences in the radiation field and 1 patient with demonstrated progression at the treatment margins. Ten lesions (27.8%) were associated with acute grade 1 cutaneous or gastrointestinal toxicity. Delayed toxicity ≥3 months after treatment included 8 cases (22.2%) of mild neuropathy, 2 (5.6%) of gastrointestinal discomfort, 8 (22.2%) of dermatitides, and 3 (8.3%) of myalgias/myositis. Thirteen

  9. Scattered fractions of dose from 18 and 25 MV X-ray radiotherapy linear accelerators

    International Nuclear Information System (INIS)

    Shobe, J.; Rodgers, J.E.; Taylor, P.L.; Jackson, J.; Popescu, G.

    1996-01-01

    Over the years, measurements have been made at a few energies to estimate the scattered fraction of dose from the patient in medical radiotherapy operations. This information has been a useful aid in the determination of shielding requirements for these facilities. With these measurements, known characteriztics of photons, and various other known parameters, Monte Carlo codes are being used to calculate the scattered fractions and hence the shielding requirements for the photons of other energies commonly used in radiotherapeutic applications. The National Institute of Standards and Technology (NIST) acquired a Sagittaire medical linear accelerator (linac) which was previously located at the Yale-New Haven Hospital. This linac provides an X-ray beam of 25 MV photons and electron beams with energies up to 32 MeV. The housing on the gantry was permanently removed from the accelerator during installation. A Varian Clinac 1800 linear accelerator was used to produce the 18 MV photons at the Frederick Memorial Hospital Regional Cancer Therapy Center in Frederick, MD. This paper represents a study of the photon dose scattered from a patient in typical radiation treatment situations as it relates to the dose delivered at the isocenter in water. The results of these measurements will be compared to Monte Carlo calculations. Photon spectral measurements were not made at this time. Neutron spectral measurements were made on this Sagittaire machine in its previous location and that work was not repeated here, although a brief study of the neutron component of the 18 and 25 MV linacs was performed utilizing thermoluminescent dosimetry (TLD) to determine the isotropy of the neutron dose. (author)

  10. Critical dose and toxicity index of organs at risk in radiotherapy: Analyzing the calculated effects of modified dose fractionation in non–small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pedicini, Piernicola, E-mail: ppiern@libero.it [Service of Medical Physics, I.R.C.C.S. Regional Cancer Hospital C.R.O.B, Rionero in Vulture (Italy); Strigari, Lidia [Laboratory of Medical Physics and Expert Systems, Regina Elena National Cancer Institute, Rome (Italy); Benassi, Marcello [Service of Medical Physics, Scientific Institute of Tumours of Romagna I.R.S.T., Meldola (Italy); Caivano, Rocchina [Service of Medical Physics, I.R.C.C.S. Regional Cancer Hospital C.R.O.B, Rionero in Vulture (Italy); Fiorentino, Alba [U.O. of Radiotherapy, I.R.C.C.S. Regional Cancer Hospital C.R.O.B., Rionero in Vulture (Italy); Nappi, Antonio [U.O. of Nuclear Medicine, I.R.C.C.S. Regional Cancer Hospital C.R.O.B., Rionero in Vulture (Italy); Salvatore, Marco [U.O. of Nuclear Medicine, I.R.C.C.S. SDN Foundation, Naples (Italy); Storto, Giovanni [U.O. of Nuclear Medicine, I.R.C.C.S. Regional Cancer Hospital C.R.O.B., Rionero in Vulture (Italy)

    2014-04-01

    To increase the efficacy of radiotherapy for non–small cell lung cancer (NSCLC), many schemes of dose fractionation were assessed by a new “toxicity index” (I), which allows one to choose the fractionation schedules that produce less toxic treatments. Thirty-two patients affected by non resectable NSCLC were treated by standard 3-dimensional conformal radiotherapy (3DCRT) with a strategy of limited treated volume. Computed tomography datasets were employed to re plan by simultaneous integrated boost intensity-modulated radiotherapy (IMRT). The dose distributions from plans were used to test various schemes of dose fractionation, in 3DCRT as well as in IMRT, by transforming the dose-volume histogram (DVH) into a biological equivalent DVH (BDVH) and by varying the overall treatment time. The BDVHs were obtained through the toxicity index, which was defined for each of the organs at risk (OAR) by a linear quadratic model keeping an equivalent radiobiological effect on the target volume. The less toxic fractionation consisted in a severe/moderate hyper fractionation for the volume including the primary tumor and lymph nodes, followed by a hypofractionation for the reduced volume of the primary tumor. The 3DCRT and IMRT resulted, respectively, in 4.7% and 4.3% of dose sparing for the spinal cord, without significant changes for the combined-lungs toxicity (p < 0.001). Schedules with reduced overall treatment time (accelerated fractionations) led to a 12.5% dose sparing for the spinal cord (7.5% in IMRT), 8.3% dose sparing for V{sub 20} in the combined lungs (5.5% in IMRT), and also significant dose sparing for all the other OARs (p < 0.001). The toxicity index allows to choose fractionation schedules with reduced toxicity for all the OARs and equivalent radiobiological effect for the tumor in 3DCRT, as well as in IMRT, treatments of NSCLC.

  11. Persistent DNA Damage in Spermatogonial Stem Cells After Fractionated Low-Dose Irradiation of Testicular Tissue

    Energy Technology Data Exchange (ETDEWEB)

    Grewenig, Angelika; Schuler, Nadine; Rübe, Claudia E., E-mail: claudia.ruebe@uks.eu

    2015-08-01

    Purpose: Testicular spermatogenesis is extremely sensitive to radiation-induced damage, and even low scattered doses to testis from radiation therapy may pose reproductive risks with potential treatment-related infertility. Radiation-induced DNA double-strand breaks (DSBs) represent the greatest threat to the genomic integrity of spermatogonial stem cells (SSCs), which are essential to maintain spermatogenesis and prevent reproduction failure. Methods and Materials: During daily low-dose radiation with 100 mGy or 10 mGy, radiation-induced DSBs were monitored in mouse testis by quantifying 53 binding protein 1 (53BP-1) foci in SSCs within their stem cell niche. The accumulation of DSBs was correlated with proliferation, differentiation, and apoptosis of testicular germ cell populations. Results: Even very low doses of ionizing radiation arrested spermatogenesis, primarily by inducing apoptosis in spermatogonia. Eventual recovery of spermatogenesis depended on the survival of SSCs and their functional ability to proliferate and differentiate to provide adequate numbers of differentiating spermatogonia. Importantly, apoptosis-resistant SSCs resulted in increased 53BP-1 foci levels during, and even several months after, fractionated low-dose radiation, suggesting that surviving SSCs have accumulated an increased load of DNA damage. Conclusions: SSCs revealed elevated levels of DSBs for weeks after radiation, and if these DSBs persist through differentiation to spermatozoa, this may have severe consequences for the genomic integrity of the fertilizing sperm.

  12. Persistent DNA Damage in Spermatogonial Stem Cells After Fractionated Low-Dose Irradiation of Testicular Tissue

    International Nuclear Information System (INIS)

    Grewenig, Angelika; Schuler, Nadine; Rübe, Claudia E.

    2015-01-01

    Purpose: Testicular spermatogenesis is extremely sensitive to radiation-induced damage, and even low scattered doses to testis from radiation therapy may pose reproductive risks with potential treatment-related infertility. Radiation-induced DNA double-strand breaks (DSBs) represent the greatest threat to the genomic integrity of spermatogonial stem cells (SSCs), which are essential to maintain spermatogenesis and prevent reproduction failure. Methods and Materials: During daily low-dose radiation with 100 mGy or 10 mGy, radiation-induced DSBs were monitored in mouse testis by quantifying 53 binding protein 1 (53BP-1) foci in SSCs within their stem cell niche. The accumulation of DSBs was correlated with proliferation, differentiation, and apoptosis of testicular germ cell populations. Results: Even very low doses of ionizing radiation arrested spermatogenesis, primarily by inducing apoptosis in spermatogonia. Eventual recovery of spermatogenesis depended on the survival of SSCs and their functional ability to proliferate and differentiate to provide adequate numbers of differentiating spermatogonia. Importantly, apoptosis-resistant SSCs resulted in increased 53BP-1 foci levels during, and even several months after, fractionated low-dose radiation, suggesting that surviving SSCs have accumulated an increased load of DNA damage. Conclusions: SSCs revealed elevated levels of DSBs for weeks after radiation, and if these DSBs persist through differentiation to spermatozoa, this may have severe consequences for the genomic integrity of the fertilizing sperm

  13. Evaluation of the efficacy of palliative irradiation with high fractionated doses and planned intervals of patients with advanced cancer of the oral cavity and pharynx

    International Nuclear Information System (INIS)

    Skolyszewski, J.; Reinfuss, M.

    1988-01-01

    200 patients, previously not treated, with advanced highly differentiated cancer of the oral cavity and pharynx have been palliatively irradiated in the Oncology Center in Cracow in the years 1976-1985. Megavoltage irradiation with fractionated doses 4-5 Gy up to the dose of 20 Gy to the tumor with 4-5 fractions during 4-7 days has been applied. 64 patients received 20 Gy as simple dose, in 65 cases such dose has been repeated after month. 71 patients have been irradiated for the third time with similar dose after another 1 month interval. Partial regression of 25-50% of the tumor volume has been obtained after the first series of irradiation in 19% of patients and more than 50% in 28% of patients, complete regression in 4% of patients. 15,5% of the total number of patients survived 1 year since the initiation of the irradiation, 5% without symptoms of the neoplasm. Worse prognosis is connected with major advancement of the tumor (T 4 , N 2 ), poor general condition, cachexia and alcohol addition. Absence of improvement after the first series of irradiations indicates the non-effectiveness of the treatment. Palliative treatment by irradiation with high fractionated doses and planned interval is a safe and efficacious method. 1 fig., 6 tabs., 14 refs. (author)

  14. Estimation of the total absorbed dose by quartz in retrospective conditions

    International Nuclear Information System (INIS)

    Correcher, V.; Delgado, A.

    2003-01-01

    The estimation of the total absorbed dose is of great interest in areas affected by a radiological accident when no conventional dosimetric systems are available. This paper reports about the usual methodology employed in dose reconstruction from the thermoluminescence (TL) properties of natural quartz, extracted from selected ceramic materials (12 bricks) picked up in the Chernobyl area. It has been possible to evaluate doses under 50mGy after more than 11 years later since the radiological accident happened. The main advance of this fact is the reduction of the commonly accepted limit dose estimation more than 20 times employing luminescence methods. (Author) 11 refs

  15. Dose calculation method with 60-cobalt gamma rays in total body irradiation

    International Nuclear Information System (INIS)

    Scaff, Luiz Alberto Malaguti

    2001-01-01

    Physical factors associated to total body irradiation using 60 Co gamma rays beams, were studied in order to develop a calculation method of the dose distribution that could be reproduced in any radiotherapy center with good precision. The method is based on considering total body irradiation as a large and irregular field with heterogeneities. To calculate doses, or doses rates, of each area of interest (head, thorax, thigh, etc.), scattered radiation is determined. It was observed that if dismagnified fields were considered to calculate the scattered radiation, the resulting values could be applied on a projection to the real size to obtain the values for dose rate calculations. In a parallel work it was determined the variation of the dose rate in the air, for the distance of treatment, and for points out of the central axis. This confirm that the use of the inverse square law is not valid. An attenuation curve for a broad beam was also determined in order to allow the use of absorbers. In this work all the adapted formulas for dose rate calculations in several areas of the body are described, as well time/dose templates sheets for total body irradiation. The in vivo dosimetry, proved that either experimental or calculated dose rate values (achieved by the proposed method), did not have significant discrepancies. (author)

  16. Single-fraction stereotactic radiotherapy: a dose-response analysis of arteriovenous malformation obliteration

    International Nuclear Information System (INIS)

    Touboul, Emmanuel; Al Halabi, Assem; Buffat, Laurent; Merienne, Louis; Huart, Judith; Schlienger, Michel; Lefkopoulos, Dimitrios; Mammar, Hamid; Missir, Odile; Meder, Jean-Francois; Laurent, Alex; Housset, Martin

    1998-01-01

    Purpose: Stereotactic radiotherapy delivered in a high-dose single fraction is an effective technique to obliterate intracranial arteriovenous malformations (AVM). To attempt to analyze the relationships between dose, volume, and obliteration rates, we studied a group of patients treated using single-isocenter treatment plans. Methods and Materials: From May 1986 to December 1989, 100 consecutive patients with angiographically proven AVM had stereotactic radiotherapy delivered as a high-dose single fraction using a single-isocenter technique. Distribution according to Spetzler-Martin grade was as follows: 79 grade 1-3, three grade 4, 0 grade 5, and 18 grade 6. The target volume was spheroid in 74 cases, ellipsoid in 11, and large and irregular in 15. The targeted volume of the nidus was estimated using two-dimensional stereotactic angiographic data and, calculated as an ovoid-shaped lesion, was 1900 ± 230 mm 3 (median 968 mm 3 ; range 62-11, 250 mm 3 ). The mean minimum target dose (D min ) was 19 ± 0.6 Gy (median 20 Gy; range: 3-31.5). The mean volume within the isodose which corresponded to the minimum target dose was 2500 ± 300 mm 3 (median 1200 mm 3 ; range 75-14 900 mm 3 ). The mean maximum dose (D max ) was 34.5 ± 0.5 Gy (median 35 Gy; range 15-45). The mean angiographic follow-up was 42 ± 2.3 months (median 37.5; range 7-117). Results: The absolute obliteration rate was 51%. The 5-year actuarial obliteration rate was 62.5 ± 7%. After univariate analysis, AVM obliteration was influenced by previous surgery (p = 0.0007), D min by steps of 5 Gy (p = 0.005), targeted volume of the nidus (≤968 mm 3 vs. >968 mm 3 ; p = 0.015), and grade according to Spetzler-Martin (grade 1-3 vs. grade 4-6; p = 0.011). After multivariate analysis, the independent factors influencing AVM obliteration were the D min [relative risk (RR) 1.9; 95% confidence interval (CI) 1.4-2.5; p min but does not seem to be influenced by D max and the targeted volume of the nidus

  17. Factors associated with pulmonary toxicity after myeloablative conditioning using fractionated total body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Hwa Kyung; Yoon, Hong In; Cho, Jae Ho [Yonsei Cancer Center, Yonsei University College of Medicine, Seoul (Korea, Republic of); and others

    2017-09-15

    Pulmonary toxicities, including infectious pneumonia (IP) and idiopathic pneumonia syndrome (IPS), are serious side effects of total body irradiation (TBI) used for myeloablative conditioning. This study aimed to evaluate clinical factors associated with IP and IPS following TBI. Fifty-eight patients with hematologic malignancies who underwent TBI before allogeneic hematopoietic stem cell transplantation between 2005 and 2014 were reviewed. Most patients (91%) received 12 Gy in 1.5 Gy fractions twice a day. Pulmonary toxicities were diagnosed based on either radiographic evidence or reduced pulmonary function, and were subdivided into IP and IPS based on the presence or absence of concurrent infection. Pulmonary toxicities developed in 36 patients (62%); 16 (28%) had IP and 20 (34%) had IPS. IP was significantly associated with increased treatment-related mortality (p = 0.028) and decreased survival (p = 0.039). Multivariate analysis revealed that the risk of developing IPS was significantly higher in patients who received stem cells from a matched unrelated donor than from a matched sibling donor (p = 0.021; hazard ratio [HR] = 12.67; 95% confidence interval [CI], 1.46–110.30). Combining other conditioning agents with cyclophosphamide produced a higher tendency to develop IP (p = 0.064; HR = 6.19; 95% CI, 0.90–42.56). IP and IPS involve different risk factors and distinct pathogeneses that should be considered when planning treatments before and after TBI.

  18. Total variation regularization for a backward time-fractional diffusion problem

    International Nuclear Information System (INIS)

    Wang, Liyan; Liu, Jijun

    2013-01-01

    Consider a two-dimensional backward problem for a time-fractional diffusion process, which can be considered as image de-blurring where the blurring process is assumed to be slow diffusion. In order to avoid the over-smoothing effect for object image with edges and to construct a fast reconstruction scheme, the total variation regularizing term and the data residual error in the frequency domain are coupled to construct the cost functional. The well posedness of this optimization problem is studied. The minimizer is sought approximately using the iteration process for a series of optimization problems with Bregman distance as a penalty term. This iteration reconstruction scheme is essentially a new regularizing scheme with coupling parameter in the cost functional and the iteration stopping times as two regularizing parameters. We give the choice strategy for the regularizing parameters in terms of the noise level of measurement data, which yields the optimal error estimate on the iterative solution. The series optimization problems are solved by alternative iteration with explicit exact solution and therefore the amount of computation is much weakened. Numerical implementations are given to support our theoretical analysis on the convergence rate and to show the significant reconstruction improvements. (paper)

  19. Factors associated with pulmonary toxicity after myeloablative conditioning using fractionated total body irradiation

    International Nuclear Information System (INIS)

    Byun, Hwa Kyung; Yoon, Hong In; Cho, Jae Ho

    2017-01-01

    Pulmonary toxicities, including infectious pneumonia (IP) and idiopathic pneumonia syndrome (IPS), are serious side effects of total body irradiation (TBI) used for myeloablative conditioning. This study aimed to evaluate clinical factors associated with IP and IPS following TBI. Fifty-eight patients with hematologic malignancies who underwent TBI before allogeneic hematopoietic stem cell transplantation between 2005 and 2014 were reviewed. Most patients (91%) received 12 Gy in 1.5 Gy fractions twice a day. Pulmonary toxicities were diagnosed based on either radiographic evidence or reduced pulmonary function, and were subdivided into IP and IPS based on the presence or absence of concurrent infection. Pulmonary toxicities developed in 36 patients (62%); 16 (28%) had IP and 20 (34%) had IPS. IP was significantly associated with increased treatment-related mortality (p = 0.028) and decreased survival (p = 0.039). Multivariate analysis revealed that the risk of developing IPS was significantly higher in patients who received stem cells from a matched unrelated donor than from a matched sibling donor (p = 0.021; hazard ratio [HR] = 12.67; 95% confidence interval [CI], 1.46–110.30). Combining other conditioning agents with cyclophosphamide produced a higher tendency to develop IP (p = 0.064; HR = 6.19; 95% CI, 0.90–42.56). IP and IPS involve different risk factors and distinct pathogeneses that should be considered when planning treatments before and after TBI

  20. Single event effects and total ionizing dose effects of typical VDMOSFET devices

    International Nuclear Information System (INIS)

    Lou Jianshe; Cai Nan; Liu Jiaxin; Wu Qinzhi; Wang Jia

    2012-01-01

    In this work, single event effects and total ionizing dose effects of typical VDMOSFET irradiated by 60 Co γ-rays and 252 Cf source were studied. The single event burnout and single event gate rupture (SEB/SEGR) effects were investigated, and the relationship between drain-source breakdown voltage and ionizing dose was obtained. The results showed that the VDMOSFET devices were sensitive to SEB and SEGR, and measures to improve their resistance to SEB and SEGR should be considered seriously for their space applications. The drain-source breakdown voltage was sensitive to total ionizing dose effects as the threshold voltage. In assessing the devices' resistance to the total ionizing dose effects, both the threshold voltage and the drain-source breakdown voltage should be taken into account. (authors)

  1. In vivo assessment of the tolerance dose of small liver volumes after single-fraction HDR irradiation

    International Nuclear Information System (INIS)

    Ricke, Jens; Seidensticker, Max; Luedemann, Lutz; Pech, Maciej; Wieners, Gero; Hengst, Susanne; Mohnike, Konrad; Cho, Chie Hee; Lopez Haenninen, Enrique; Al-Abadi, Hussain; Felix, Roland; Wust, Peter

    2005-01-01

    Purpose: To prospectively assess a dose-response relationship for small volumes of liver parenchyma after single-fraction irradiation. Methods and Materials: Twenty-five liver metastases were treated by computed tomography (CT)-guided interstitial brachytherapy. Magnetic resonance imaging was performed 1 day before and 3 days and 6, 12, and 24 weeks after therapy. MR sequences included T1-w gradient echo (GRE) enhanced by hepatocyte-targeted gadobenate dimeglumine. All MRI data sets were merged with 3D dosimetry data and evaluated by two radiologists. The reviewers indicated the border of hyperintensity on T2-w images (edema) or hypointensity on T1-w images (loss of hepatocyte function). Based on the total 3D data, a dose-volume histogram was calculated. We estimated the threshold dose for either edema or function loss as the D 90 , i.e., the dose achieved in at least 90% of the pseudolesion volume. Results: Between 3 days and 6 weeks, the extension of the edema increased significantly from the 12.9 Gy isosurface to 9.9 Gy (standard deviation [SD], 3.3 and 2.6). No significant change was detected between 6 and 12 weeks. After 24 weeks, the edematous tissue had shrunk significantly to 14.7 Gy (SD, 4.2). Three days postbrachytherapy, the D 90 for hepatocyte function loss reached the 14.9 Gy isosurface (SD, 3.9). At 6 weeks, the respective zone had increased significantly to 9.9 Gy (SD, 2.3). After 12 and 24 weeks, the dysfunction volume had decreased significantly to the 11.9 Gy and 15.2 Gy isosurface, respectively (SD, 3 and 4.1). Conclusions: The 95% interval from 7.6 to 12.2 Gy found as the minimal hepatocyte tolerance after 6 weeks accounts for the radiobiologic variations found in CT-guided brachytherapy, including heterogeneous dose rates by variable catheter arrays

  2. Clinical results of definitive-dose (50 Gy/25 fractions) preoperative chemoradiotherapy for unresectable esophageal cancer

    International Nuclear Information System (INIS)

    Ishikawa, Kazuki; Nakamatsu, Kiyoshi; Shiraishi, Osamu; Yasuda, Takushi; Nishimura, Yasumasa

    2015-01-01

    The clinical results of definitive-dose preoperative chemoradiotherapy (CRT) of 50 Gy/25 fractions/5 weeks for unresectable esophageal cancer were analyzed. Inclusion criteria were unresectable esophageal squamous cell carcinoma with T4b or mediastinal lymph nodes invading to the trachea or aorta. Radiation therapy of 50 Gy/25 fractions/5 weeks was combined concurrently with two courses of FP therapy (CDDP 70 mg/m 2 + 5-FU 700 mg/m 2 /d x 5 days: day 1-5, day 29-33). Tumor response was evaluated 4 weeks after completion of RT. Subtotal esophagectomy was planned 6-8 weeks after RT. Thirty patients (26 male and 4 female) aged from 50-78 years (median 66) were enrolled between 2008 and 2011. The clinical stages according to the 7th edition of UICC were stages II/III/IV, 1/23/6; T1/2/3/4, 1/1/4/24; and N0/1/2/3, 3/25/1/1. All 30 patients completed RT of 50 Gy/ 25 fractions. Initial tumor responses were 21 patients with resectable disease, 7 with unresectable disease, and 2 with progressive disease. Subtotal esophagectomy was performed in 18 (60%) of the 30 patients. Pathological complete response was obtained in five (28%) patients. There were two patients with hospitalization death after surgery (11%). Six of the 7 patients who still had unresectable disease were treated with 1-3 courses of docetaxel, CDDP and 5-FU. Three patients treated without surgery showed long-term survival. The 3-year locoregional control rate and the 3-year overall survival rate for the 30 patients were 70 and 49%, respectively. Definitive-dose preoperative CRT was feasible, and is a promising treatment strategy for unresectable esophageal cancer. (author)

  3. Cell kinetic changes in the follicular epithelium of pig skin after irradiation with single and fractionated doses of X rays

    International Nuclear Information System (INIS)

    Morris, G.M.; Hopewell, J.W.

    1989-01-01

    Changes in cell kinetics of the follicular epithelium of the pig were studied after x-irradiation with single and fractionated doses (30 fractions/39 days) and compared with previous epidermal data. In the follicular epithelium there was an initial degenerative phase, when the rate of cell depletion was independent of radiation dose and mode of administration. Repopulation was seen between the 14th and 18th days after single doses (15 or 20 Gy) and by the 28th day after the start of irradiation with fractionated doses (52.3-80.0 Gy). The degree of cell depletion and subsequent rate of repopulation were independent of dose. The regenerative phase was characterized by an increased cell proliferation. Islands of cells with appearance similar to cells in the normal follicular epithelium, were seen 18 days after a single dose of 20 Gy and 42 days after the start of fractionated irradiation. Compared with the epidermis, the follicular epithelium exhibited considerably less evidence of damage after both single and fractionated doses. There was a lower incidence of degenerate cells and reduced levels of cell depletion in the follicular epithelium. (author)

  4. Concurrent cisplatin, infusional fluorouracil, and conventionally fractionated radiation therapy in head and neck cancer: Dose-limiting mucosal toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Denham, J.W.; Abbott, R.L. (Royal Adelaide Hospital (Australia))

    1991-03-01

    After a preliminary dose-finding study involving 12 patients with advanced or locally recurrent head and neck cancer, 27 patients were treated on a phase II protocol, using fluorouracil 350 mg/m2/d by continuous intravenous (IV) infusion over 5 days, followed on the sixth day by a 2-hour IV infusion of cisplatin 50 mg/m2, administered during the first and fourth weeks of radiation therapy to total doses between 60 and 64 Gy, using 2 Gy daily fractions. Eight of these 27 patients had American Joint Committee on Cancer Staging (AJCC) stage III disease, and 12 had stage IV disease. Four had recurrent disease after surgery. Three-year follow-up is now available. Twenty-one (77.8%) remitted completely following treatment, and 11 remain free of local and regional relapse at 3 years. Four have developed systemic metastases. Following successful salvage treatment in two cases, estimated determinate survival at 3 years is 64%. Acute toxicity was manageable with this regime. Eleven instances of grade 3 Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) mucositis were observed, which caused interruptions to radiotherapy in only four cases. No late sequelae have so far been recorded. It is concluded that the protocol described is tolerable but probably did not cause a greater number of locoregional cures than would have been expected following conventional radiotherapy alone in this group of patients. The use of infusional fluorouracil with concurrent conventionally fractionated radiation therapy and cisplatin infusion results in mucositis that limits the dose of fluorouracil to levels that are probably subtherapeutic.

  5. Serum protein concentration in low-dose total body irradiation of normal and malnourished rats

    International Nuclear Information System (INIS)

    Viana, W.C.M.; Lambertz, D.; Borges, E.S.; Neto, A.M.O.; Lambertz, K.M.F.T.; Amaral, A.

    2016-01-01

    Among the radiotherapeutics' modalities, total body irradiation (TBI) is used as treatment for certain hematological, oncological and immunological diseases. The aim of this study was to evaluate the long-term effects of low-dose TBI on plasma concentration of total protein and albumin using prematurely and undernourished rats as animal model. For this, four groups with 9 animals each were formed: Normal nourished (N); Malnourished (M); Irradiated Normal nourished (IN); Irradiated Malnourished (IM). At the age of 28 days, rats of the IN and IM groups underwent total body gamma irradiation with a source of cobalt-60. Total protein and Albumin in the blood serum was quantified by colorimetry. This research indicates that procedures involving low-dose total body irradiation in children have repercussions in the reduction in body-mass as well as in the plasma levels of total protein and albumin. Our findings reinforce the periodic monitoring of total serum protein and albumin levels as an important tool in long-term follow-up of pediatric patients in treatments associated to total body irradiation. - Highlights: • Low-dose total body irradiation (TBI) in children have repercussions in their body-mass. • Long-term total protein and albumin levels are affected by TBI. • The monitoring of total protein and albumin levels are useful in the follow-up of TBI pediatric patients.

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

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  7. The determination of the inhalable fraction of 40K activity in marijuana (Cannabis sativa L. buds by instrumental neutron activation analysis and the effective dose to the body

    Directory of Open Access Journals (Sweden)

    Johann M.R. Antoine

    2017-07-01

    Full Text Available Total potassium in marijuana (Cannabis sativa L. buds was determined using instrumental neutron activation analysis. The mass fraction of 40K and its activity were derived using the natural isotopic ratios of potassium. The total potassium in the marijuana buds ranged from 0.84% to 3.15% with a mean mass fraction of 1.93%. The activity concentrations of 40K in the samples of marijuana ranged from 253 to 946 Bq kg−1 with a mean activity concentration of 581 Bq kg−1. The effective dose to the body from smoking marijuana is lower than that for comparable tobacco smoking. Simulated smoking experiments show that over 90% of 40K is retained in the cigarette ash. Accepted methods of determining effective dose to the body from 40K inhalation are likely overestimations for both marijuana and tobacco cigarette smoke.

  8. Neuropsychological function in adults after high dose fractionated radiation therapy of skull base tumors

    International Nuclear Information System (INIS)

    Glosser, Guila; McManus, Pat; Munzenrider, John; Austin-Seymour, Mary; Fullerton, Barbara; Adams, Judy; Urie, Marcia M.

    1997-01-01

    Purpose: To evaluate the long term effects of high dose fractionated radiation therapy on brain functioning prospectively in adults without primary brain tumors. Methods and Materials: Seventeen patients with histologically confirmed chordomas and low grade chondrosarcomas of the skull base were evaluated with neuropsychological measures of intelligence, language, memory, attention, motor function and mood following surgical resection/biopsy of the tumor prior to irradiation, and then at about 6 months, 2 years and 4 years following completion of treatment. None received chemotherapy. Results: In the patients without tumor recurrence or radiation necrosis, there were no indications of adverse effects on cognitive functioning in the post-acute through the late stages after brain irradiation. Even in patients who received doses of radiation up to 66 Cobalt Gy equivalent through nondiseased (temporal lobe) brain tissue, memory and cognitive functioning remained stable for up to 5 years after treatment. A mild decline in psycho-motor speed was seen in more than half of the patients, and motor slowing was related to higher radiation doses in midline and temporal lobe brain structures. Conclusion: Results suggest that in adults, tolerance for focused radiation is relatively high in cortical brain structures

  9. Inter fraction variations in rectum and bladder volumes and dose distributions during high dose rate brachytherapy treatment of the uterine cervix investigated by repetitive CT-examinations

    International Nuclear Information System (INIS)

    Hellebust, Taran Paulsen; Dale, Einar; Skjoensberg, Ane; Olsen, Dag Rune

    2001-01-01

    Purpose: To evaluate variation of dose to organs at risk for patients receiving fractionated high dose rate gynaecological brachytherapy by using CT-based 3D treatment planning and dose-volume histograms (DVH). Materials and methods: Fourteen patients with cancer of the uterine cervix underwent three to six CT examinations (mean 4.9) during their course of high-dose-rate brachytherapy using radiographically compatible applicators. The rectal and bladder walls were delineated and DVHs were calculated. Results: Inter fraction variation of the bladder volume (CV mean =44.1%) was significantly larger than the inter fraction variation of the mean dose (CV mean =19.9%, P=0.005) and the maximum dose (CV mean =17.5%, P=0.003) of the bladder wall. The same trend was seen for rectum, although the figures were not significantly different. Performing CT examinations at four of seven brachytherapy fractions reduced the uncertainty to 4 and 7% for the bladder and rectal doses, respectively. A linear regression analysis showed a significant, negative relationship between time after treatment start and the whole bladder volume (P=0.018), whereas no correlation was found for the rectum. For both rectum and bladder a linear regression analysis revealed a significant, negative relationship between the whole volume and median dose (P<0.05). Conclusion: Preferably a CT examination should be provided at every fraction. However, this is logistically unfeasible in most institutions. To obtain reliable DVHs the patients will in the future undergo 3-4 CT examinations during the course of brachytherapy at our institution. Since this study showed an association between large bladder volumes and dose reductions, the patients will be treated with a standardized bladder volume

  10. SU-D-BRB-06: Treating Glioblastoma Multiforme (GBM) as a Chronic Disease: Implication of Temporal-Spatial Dose Fractionation Optimization Including Cancer Stem Cell Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Yu, V; Nguyen, D; Pajonk, F; Kaprealian, T; Kupelian, P; Steinberg, M; Low, D; Sheng, K [Department of Radiation Oncology, UCLA, Los Angeles, CA (United States)

    2015-06-15

    Purpose: To explore the feasibility of improving GBM treatment outcome with temporal-spatial dose optimization of an ordinary differential equation (ODE) that models the differentiation and distinct radiosensitivity between cancer stem cells (CSC) and differentiated cancer cells (DCC). Methods: The ODE was formulated into a non-convex optimization problem with the objective to minimize remaining total cancer cells 500 days from the onset of radiotherapy when the total cancer cell number was 3.5×10{sup 7}, while maintaining normal tissue biological effective dose (BED) of 100Gy resulted from standard prescription of 2Gyx30. Assuming spatially separated CSC and DCC, optimization was also performed to explore the potential benefit from dose-painting the two compartments. Dose escalation to a sub-cell-population in the GTV was also examined assuming that a 2 cm margin around the GTV allows sufficient dose drop-off to 100Gy BED. The recurrence time was determined as the time at which the total cancer cell number regrows to 10{sup 9} cells. Results: The recurrence time with variable fractional doses administered once per week, bi-week and month for one year were found to be 615, 593 and 570 days, superior to the standard-prescription recurrence time of 418 days. The optimal dose-fraction size progression for both uniform and dose-painting to the tumor is low and relatively constant in the beginning and gradually increases to more aggressive fractions at end of the treatment course. Dose escalation to BED of 200Gy to the whole tumor alongside with protracted weekly treatment was found to further delay recurrence to 733 days. Dose-painting of 200 and 500Gy BED to CSC on a year-long weekly schedule further extended recurrence to 736 and 1076 days, respectively. Conclusion: GBM treatment outcome can possibly be improved with a chronic treatment approach. Further dose escalation to the entire tumor or CSC targeted killing is needed to achieve total tumor control. This work

  11. Prescription dose and fractionation predict improved survival after stereotactic radiotherapy for brainstem metastases

    Directory of Open Access Journals (Sweden)

    Leeman Jonathan E

    2012-07-01

    Full Text Available Abstract Background Brainstem metastases represent an uncommon clinical presentation that is associated with a poor prognosis. Treatment options are limited given the unacceptable risks associated with surgical resection in this location. However, without local control, symptoms including progressive cranial nerve dysfunction are frequently observed. The objective of this study was to determine the outcomes associated with linear accelerator-based stereotactic radiotherapy or radiosurgery (SRT/SRS of brainstem metastases. Methods We retrospectively reviewed 38 tumors in 36 patients treated with SRT/SRS between February 2003 and December 2011. Treatment was delivered with the Cyberknife™ or Trilogy™ radiosurgical systems. The median age of patients was 62 (range: 28–89. Primary pathologies included 14 lung, 7 breast, 4 colon and 11 others. Sixteen patients (44% had received whole brain radiation therapy (WBRT prior to SRT/SRS; ten had received prior SRT/SRS at a different site (28%. The median tumor volume was 0.94 cm3 (range: 0.01-4.2 with a median prescription dose of 17 Gy (range: 12–24 delivered in 1–5 fractions. Results Median follow-up for the cohort was 3.2 months (range: 0.4-20.6. Nineteen patients (52% had an MRI follow-up available for review. Of these, one patient experienced local failure corresponding to an actuarial 6-month local control of 93%. Fifteen of the patients with available follow-up imaging (79% experienced intracranial failure outside of the treatment volume. The median time to distant intracranial failure was 2.1 months. Six of the 15 patients with distant intracranial failure (40% had received previous WBRT. The actuarial overall survival rates at 6- and 12-months were 27% and 8%, respectively. Predictors of survival included Graded Prognostic Assessment (GPA score, greater number of treatment fractions, and higher prescription dose. Three patients experienced acute treatment-related toxicity consisting of

  12. Molecular mechanisms involved in modulation of p-glycoprotein expression from squamous cell carcinoma by low dose fractionated radiation (LDFR)

    International Nuclear Information System (INIS)

    Shajahan; Shahin; Shareef, Mohammed M.; Sathishkumar, Sabapathi; Mohiuddin, Mohammed; Ahmed, Mansoor M.; Brown, Brandee C.; Jones, Raleigh; Spring, Paul M.

    2004-01-01

    In the present study, two squamous cell carcinoma oral cavity cells (SCCOC), T-167 (p53 wild type) and T-409 (p53 mutant), were exposed to either clinically relevant dose (2 Gy), high dose (7Gy) or fractionated low dose (LDFR) (0.5 Gy x 4) and the expression of Mdr1 gene was assessed by real time RT-PCR, semiquantitative 32 P RT-PCR and luciferase reporter assay

  13. Enhancement of Transistor-to-Transistor Variability Due to Total Dose Effects in 65-nm MOSFETs

    CERN Document Server

    Gerardin, S; Cornale, D; Ding, L; Mattiazzo, S; Paccagnella, A; Faccio, F; Michelis, S

    2015-01-01

    We studied device-to-device variations as a function of total dose in MOSFETs, using specially designed test structures and procedures aimed at maximizing matching between transistors. Degradation in nMOSFETs is less severe than in pMOSFETs and does not show any clear increase in sample-to-sample variability due to the exposure. At doses smaller than 1 Mrad( SiO2) variability in pMOSFETs is also practically unaffected, whereas at very high doses-in excess of tens of Mrad( SiO2)-variability in the on-current is enhanced in a way not correlated to pre-rad variability. The phenomenon is likely due to the impact of random dopant fluctuations on total ionizing dose effects.

  14. 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

  15. Safety aspects of preoperative high-dose glucocorticoid in primary total knee replacement

    DEFF Research Database (Denmark)

    Jørgensen, C C; Pitter, F T; Kehlet, H

    2017-01-01

    Background: Preoperative single high-dose glucocorticoid may have early outcome benefits in total hip arthroplasty (THA) and knee arthroplasty (TKA), but long-term safety aspects have not been evaluated. Methods: From October 2013, the departments reporting to the prospective Lundbeck Foundation....... Conclusions: In this detailed prospective cohort study, preoperative high-dose glucocorticoid administration was not associated with LOS >4 days, readmissions or infectious complications in TKA patients without contraindications....

  16. Total dose effects on ATLAS-SCT front-end electronics

    CERN Document Server

    Ullán, M; Dubbs, T; Grillo, A A; Spencer, E; Seiden, A; Spieler, H; Gilchriese, M G D; Lozano, M

    2002-01-01

    Low dose rate effects (LDRE) in bipolar technologies complicate the hardness assurance testing for high energy physics applications. The damage produced in the ICs in the real experiment can be underestimated if fast irradiations are carried out, while experiments done at the real dose rate are usually unpractical due to the still high total doses involved. In this work the sensitivity to LDRE of two bipolar technologies proposed for the ATLAS-SCT experiment at CERN is evaluated, finding one of them free of those effects. (12 refs).

  17. The total dose effects on the 1/f noise of deep submicron CMOS transistors

    International Nuclear Information System (INIS)

    Hu Rongbin; Wang Yuxin; Lu Wu

    2014-01-01

    Using 0.18 μm CMOS transistors, the total dose effects on the 1/f noise of deep-submicron CMOS transistors are studied for the first time in mainland China. From the experimental results and the theoretic analysis, we realize that total dose radiation causes a lot of trapped positive charges in STI (shallow trench isolation) SiO 2 layers, which induces a current leakage passage, increasing the 1/f noise power of CMOS transistors. In addition, we design some radiation-hardness structures on the CMOS transistors and the experimental results show that, until the total dose achieves 750 krad, the 1/f noise power of the radiation-hardness CMOS transistors remains unchanged, which proves our conclusion. (semiconductor devices)

  18. Second Study of Hyper-Fractionated Radiotherapy

    Directory of Open Access Journals (Sweden)

    R. Jacob

    1999-01-01

    Full Text Available Purpose and Method. Hyper-fractionated radiotherapy for treatment of soft tissue sarcomas is designed to deliver a higher total dose of radiation without an increase in late normal tissue damage. In a previous study at the Royal Marsden Hospital, a total dose of 75 Gy using twice daily 1.25 Gy fractions resulted in a higher incidence of late damage than conventional radiotherapy using 2 Gy daily fractions treating to a total of 60 Gy. The current trial therefore used a lower dose per fraction of 1.2 Gy and lower total dose of 72 Gy, with 60 fractions given over a period of 6 weeks.

  19. Immunogenicity of fractional doses of tetravalent a/c/y/w135 meningococcal polysaccharide vaccine: results from a randomized non-inferiority controlled trial in Uganda.

    Directory of Open Access Journals (Sweden)

    Philippe J Guerin

    Full Text Available Neisseria meningitidis serogroup A is the main causative pathogen of meningitis epidemics in sub-Saharan Africa. In recent years, serogroup W135 has also been the cause of epidemics. Mass vaccination campaigns with polysaccharide vaccines are key elements in controlling these epidemics. Facing global vaccine shortage, we explored the use of fractional doses of a licensed A/C/Y/W135 polysaccharide meningococcal vaccine.We conducted a randomized, non-inferiority trial in 750 healthy volunteers 2-19 years old in Mbarara, Uganda, to compare the immune response of the full dose of the vaccine versus fractional doses (1/5 or 1/10. Safety and tolerability data were collected for all subjects during the 4 weeks following the injection. Pre- and post-vaccination sera were analyzed by measuring serum bactericidal activity (SBA with baby rabbit complement. A responder was defined as a subject with a > or =4-fold increase in SBA against a target strain from each serogroup and SBA titer > or =128. For serogroup W135, 94% and 97% of the vaccinees in the 1/5- and 1/10-dose arms, respectively, were responders, versus 94% in the full-dose arm; for serogroup A, 92% and 88% were responders, respectively, versus 95%. Non-inferiority was demonstrated between the full dose and both fractional doses in SBA seroresponse against serogroups W135 and Y, in total population analysis. Non-inferiority was shown between the full and 1/5 doses for serogroup A in the population non-immune prior to vaccination. Non-inferiority was not shown for any of the fractionate doses for serogroup C. Safety and tolerability data were favourable, as observed in other studies.While the advent of conjugate A vaccine is anticipated to largely contribute to control serogroup A outbreaks in Africa, the scale-up of its production will not cover the entire "Meningitis Belt" target population for at least the next 3 to 5 years. In view of the current shortage of meningococcal vaccines for Africa

  20. The effects of high dose and highly fractionated radiation on distraction osteogenesis in the murine mandible

    International Nuclear Information System (INIS)

    Monson, Laura A; Cavaliere, Christi M; Deshpande, Sagar S; Ayzengart, Alexander L; Buchman, Steven R

    2012-01-01

    The ability of irradiated tissue to support bony growth remains poorly defined, although there are anecdotal cases reported showing mixed results for the use of mandibular distraction osteogenesis after radiation for head and neck cancer. Many of these reports lack objective measures that would allow adequate analysis of outcomes or efficacy. The purpose of this experiment was to utilize a rat model of mandibular distraction osteogenesis after high dose and highly fractionated radiation therapy and to evaluate and quantify distracted bone formation under these conditions. Male Sprague–Dawley rats underwent 12 fractions of external beam radiation (48 Gray) of the left mandible. Following a two week recovery period, an external frame distractor was applied and gradual distraction of the mandible was performed. Tissue was harvested after a twenty-eight day consolidation period. Gross, radiologic and histological evaluations were undertaken. Those animals subjected to pre-operative radiation showed severe attenuation of bone formation including bone atrophy, incomplete bridging of the distraction gap, and gross bony defects or non-union. Although physical lengthening was achieved, the irradiated bone consistently demonstrated marked damaging effects on the normal process of distraction osteogenesis. This murine model has provided reliable evidence of the injurious effects of high dose radiation on bone repair and regeneration in distraction osteogenesis utilizing accurate and reproducible metrics. These results can now be used to assist in the development of therapies directed at mitigating the adverse consequences of radiation on the regeneration of bone and to optimize distraction osteogenesis so it can be successfully applied to post-oncologic reconstruction

  1. The Effects of Radiation and Dose-Fractionation on Cancer and Non-Tumor Disease Development

    Directory of Open Access Journals (Sweden)

    Gayle E. Woloschak

    2012-12-01

    Full Text Available The Janus series of radiation experiments, conducted from 1970 to 1992, explored the effects of gamma and neutron radiation on animal lifespan and disease development. Data from these experiments presents an opportunity to conduct a large scale analysis of both tumor and non-tumor disease development. This work was focused on a subset of animals from the Janus series of experiments, comparing acute or fractionated exposures of gamma or neutron radiation on the hazards associated with the development of tumor and non-tumor diseases of the liver, lung, kidney or vascular system. This study also examines how the co-occurrence of non-tumor diseases may affect tumor-associated hazards. While exposure to radiation increases the hazard of dying with tumor and non-tumor diseases, dose fractionation modulates these hazards, which varies across different organ systems. Finally, the effect that concurrent non-cancer diseases have on the hazard of dying with a tumor also differs by organ system. These results highlight the complexity in the effects of radiation on the liver, lung, kidney and vascular system.

  2. Fractionation in normal tissues: the (α/β)eff concept can account for dose heterogeneity and volume effects.

    Science.gov (United States)

    Hoffmann, Aswin L; Nahum, Alan E

    2013-10-07

    The simple Linear-Quadratic (LQ)-based Withers iso-effect formula (WIF) is widely used in external-beam radiotherapy to derive a new tumour dose prescription such that there is normal-tissue (NT) iso-effect when changing the fraction size and/or number. However, as conventionally applied, the WIF is invalid unless the normal-tissue response is solely determined by the tumour dose. We propose a generalized WIF (gWIF) which retains the tumour prescription dose, but replaces the intrinsic fractionation sensitivity measure (α/β) by a new concept, the normal-tissue effective fractionation sensitivity, [Formula: see text], which takes into account both the dose heterogeneity in, and the volume effect of, the late-responding normal-tissue in question. Closed-form analytical expressions for [Formula: see text] ensuring exact normal-tissue iso-effect are derived for: (i) uniform dose, and (ii) arbitrary dose distributions with volume-effect parameter n = 1 from the normal-tissue dose-volume histogram. For arbitrary dose distributions and arbitrary n, a numerical solution for [Formula: see text] exhibits a weak dependence on the number of fractions. As n is increased, [Formula: see text] increases from its intrinsic value at n = 0 (100% serial normal-tissue) to values close to or even exceeding the tumour (α/β) at n = 1 (100% parallel normal-tissue), with the highest values of [Formula: see text] corresponding to the most conformal dose distributions. Applications of this new concept to inverse planning and to highly conformal modalities are discussed, as is the effect of possible deviations from LQ behaviour at large fraction sizes.

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  4. An experimental study on total dose effects in SRAM-based FPGAs

    International Nuclear Information System (INIS)

    Yao Zhibin; He Baoping; Zhang Fengqi; Guo Hongxia; Luo Yinhong; Wang Yuanming; Zhang Keying

    2009-01-01

    In order to study testing methods and find sensitive parameters in total dose effects on SRAM-based FPGA, XC2S100 chips were irradiated by 60 Co γ-rays and tested with two test circuit designs. By analyzing the experimental results, the test flow of configuration RAM and bock RAM was given, and the most sensitive parameter was obtained. The results will be a solid foundation for establishing test specification and evaluation methods of total dose effects on SRAM-based FPGAs. (authors)

  5. Single-dose radiation therapy for prevention of heterotopic ossification after total hip arthroplasty

    International Nuclear Information System (INIS)

    Healy, W.L.; Lo, T.C.; Covall, D.J.; Pfeifer, B.A.; Wasilewski, S.A.

    1990-01-01

    Single-dose radiation therapy was prospectively evaluated for its efficacy in prevention of heterotopic ossification in patients at high risk after total hip arthroplasty. Thirty-one patients (34 hips) were treated between 1981 and 1988. Risk factors for inclusion in the protocol included prior evidence of heterotopic ossification, ankylosing spondylitis, and diffuse idiopathic skeletal hyperostosis. Patients with hypertrophic osteoarthritis or traumatic arthritis with osteophytes were not included. Operations on 34 hips included 19 primary total and 11 revision total hip arthroplasties and 4 excisions of heterotopic ossification. All patients received radiotherapy to the hip after operation with a single dose of 700 centigray. Radiotherapy is recommended on the first postoperative day. After this single-dose radiation treatment, no patient had clinically significant heterotopic ossification. Recurrent disease developed in two hips (6%), as seen on radiography (grades 2 and 3). This series documents a 100% clinical success rate and a 94% radiographic success rate in preventing heterotopic ossification in patients at high risk after total hip arthroplasty. Single-dose radiotherapy is as effective as other radiation protocols in preventing heterotopic ossification after total hip arthroplasty. It is less expensive and easier to administer than multidose radiotherapy

  6. Modelling the variation in rectal dose due to inter-fraction rectal wall deformation in external beam prostate treatments

    International Nuclear Information System (INIS)

    Booth, Jeremy; Zavgorodni, Sergei

    2005-01-01

    Prostate radiotherapy inevitably deposits radiation dose in the rectal wall, and the dose delivered to prostate is limited by the expected rectal complications. Accurate evaluation of the rectal dose is non-trivial due to a number of factors. One of these is variation of the shape and position of the rectal wall (with respect to the clinical target volume (CTV)), which may differ daily from that taken during planning CT acquisition. This study uses data currently available in the literature on rectal wall motion to provide estimates of mean population rectal wall dose. The rectal wall geometry is characterized by a population mean radius of the rectum as well as inter-patient and inter-fraction standard deviations in rectum radius. The model is used to evaluate the range of inter-fraction and inter-patient rectal dose variations. The simulation of individual patients with full and empty rectum in the planning CT scan showed that large variations in rectal dose (>15 Gy) are possible. Mean calculated dose accounting for treatment and planning uncertainties in the rectal wall surface was calculated as well as the map of planning dose over/underpredictions. It was found that accuracy of planning dose is dependent on the CTV-PTV margin size with larger margins producing more accurate estimates. Over a patient population, the variation in rectal dose is reduced by increasing the number of pre-treatment CT scans

  7. Fractional-Dose Inactivated Poliovirus Vaccine Campaign - Sindh Province, Pakistan, 2016.

    Science.gov (United States)

    Pervaiz, Aslam; Mbaeyi, Chukwuma; Baig, Mirza Amir; Burman, Ashley; Ahmed, Jamal A; Akter, Sharifa; Jatoi, Fayaz A; Mahamud, Abdirahman; Asghar, Rana Jawad; Azam, Naila; Shah, Muhammad Nadeem; Laghari, Mumtaz Ali; Soomro, Kamaluddin; Wadood, Mufti Zubair; Ehrhardt, Derek; Safdar, Rana M; Farag, Noha

    2017-12-01

    Following the declaration of eradication of wild poliovirus (WPV) type 2 in September 2015, trivalent oral poliovirus vaccine (tOPV) was withdrawn globally to reduce the risk for type 2 vaccine-derived poliovirus (VDPV2) transmission; all countries implemented a synchronized switch to bivalent OPV (type 1 and 3) in April 2016 (1,2). Any isolation of VDPV2 after the switch is to be treated as a potential public health emergency and might indicate the need for supplementary immunization activities (3,4). On August 9, 2016, VDPV2 was isolated from a sewage sample taken from an environmental surveillance site in Hyderabad, Sindh province, Pakistan. Possible vaccination activities in response to VDPV2 isolation include the use of injectable inactivated polio vaccine (IPV), which poses no risk for vaccine-derived poliovirus transmission. Fractional-dose, intradermal IPV (fIPV), one fifth of the standard intramuscular dose, has been developed to more efficiently manage limited IPV supplies. fIPV has been shown in some studies to be noninferior to full-dose IPV (5,6) and was used successfully in response to a similar detection of a single VDPV2 isolate from sewage in India (7). Injectable fIPV was used for response activities in Hyderabad and three neighboring districts. This report describes the findings of an assessment of preparatory activities and subsequent implementation of the fIPV campaign. Despite achieving high coverage (>80%), several operational challenges were noted. The lessons learned from this campaign could help to guide the planning and implementation of future fIPV vaccination activities.

  8. Enchanced total dose damage in junction field effect transistors and related linear integrated circuits

    International Nuclear Information System (INIS)

    Flament, O.; Autran, J.L.; Roche, P.; Leray, J.L.; Musseau, O.

    1996-01-01

    Enhanced total dose damage of Junction Field-effect Transistors (JFETs) due to low dose rate and/or elevated temperature has been investigated for elementary p-channel structures fabricated on bulk and SOI substrates as well as for related linear integrated circuits. All these devices were fabricated with conventional junction isolation (field oxide). Large increases in damage have been revealed by performing high temperature and/or low dose rate irradiations. These results are consistent with previous studies concerning bipolar field oxides under low-field conditions. They suggest that the transport of radiation-induced holes through the oxide is the underlying mechanism. Such an enhanced degradation must be taken into account for low dose rate effects on linear integrated circuits

  9. Influence of fractionation of dose on 3 year results of X-ray therapy of skin cancer

    International Nuclear Information System (INIS)

    Szymczyk, W.; Radziszewska, J.; Cyplik, I.; Glinska, H.

    1985-01-01

    Three-year results of X-ray therapy of skin cancer in 345 patients are presented. The dependence of results on the size of irradiated field and the method of dose fractionation is analysed. The clinical usefulness of a cumulative radiation effect (CRE) is evaluated. 96.5% of three-year cures were obtained. Recurrences amounted to 1.6% and necroses to 1.9% of treated lesions. It has been shown that treatment of small fields with 8-fractions gave equally positive results as with 15-fractions whereas in the treatment of large lesions the selection of CRE value, a number of fractions and dose should let the value of CRE minimally exceeds the level of tolerance of healthy tissues. The regard to CRE value in the treatment of large lesions or the introduction of additional dosimetric acts seems to be useful. 10 refs., 1 fig., 5 tabs. (author)

  10. Fractionated dose studies with X-rays and various alkylating agents in P388 mouse lymphoma cells

    International Nuclear Information System (INIS)

    Anderson, D.

    1981-01-01

    The fractionated dose technique has been used in P388F cells to examine the effects of X-rays and four alkylating agents on survival and induction of 5-iodo-2-deoxyuridine (IudR) resistant variants. Fractionation intervals up to 5 1/2 h were used for X-rays and for the alkylating agents up to 192 h. Fractionation of the X-ray dose resulted in a sparing effect for survival and variant induction. A sparing effect was also observed for survival after treatment with alkylating agents. However, variant frequencies were observed as large as or greater than those produced by the full doses of alkylating agents. For such agents this would suggest that survival and variant induction are independent events. Differences in the effects of X-rays and alkylating agents cannot be explained by differences in growth rate or the recovery of viability after treatment

  11. Fractionated dose studies with X-rays and various alkylating agents in P388 mouse lymphoma cells

    International Nuclear Information System (INIS)

    Anderson, D.

    1981-01-01

    The fractionated dose technique was used in P388F cells to examine the effects of X-rays and four alkylating agents on survival and induction of 5-iodo-2-deoxyuridine (IudR) resistant variants. Fractionation intervals up to 51/2 h were used for X-rays and for the alkylating agents up to 192 h. Fractionation of the X-ray dose resulted in a sparing effect for survival and variant induction. A sparing effect was also observed for survival after treatment with alkylating agents. However, variant frequencies were observed as large as or greater than those produced by the full doses of alkylating agents. For such agents this would suggest that survival and variant induction are independent events. Differences in the effects of X-rays and alkylating agents cannot be explained by differences in growth rate or the recovery of viability after treatment. (author)

  12. The relative biological effectiveness of fractionated doses of fast neutrons (42 MeVd→Be) for normal tissues. Pt. 3

    International Nuclear Information System (INIS)

    Rezvani, M.; Hopewell, J.W.; Robbins, M.E.C.; Hamlet, R.; Barnes, D.W.H.; Sansom, J.M.; Adams, P.J.V.

    1990-01-01

    The effect of single and fractionated doses of fast neutrons (42 MeV d→Bc ) on the early and late radiation responses of the pig lung have been assessed by the measurement of changes in lung function using a 133 Xe washout technique. The results obtained for irradiation schedules with fast neutrons have been compared with those after photon irradiation. There was no statistically significant difference between the values for the relative biological effectiveness (RBE) for the early and late radiation response of the lung. The RBE of the neutron beam increased with decreasing size of dose/fraction with an upper limit value of 4.39 ± 0.94 for infinitely small X-ray doses per fraction. (author)

  13. Radiation-induced rectal complications are not influenced by age: a dose fractionation study in the rat.

    Science.gov (United States)

    van den Aardweg, Gerard J M J; Olofsen-van Acht, Manouk J J; van Hooije, Christel M C; Levendag, Peter C

    2003-05-01

    Radiation-induced complications of the rectum are an important dose-limiting factor in radiotherapy of pelvic malignancies. In general, animal studies demonstrated no differences in acute and late normal tissue toxicity with age, but little is known about rectal complications in relation to age. For this purpose, an extensive histological and dose fractionation study was carried out on the rectum of young (12 weeks) and older (77-80 weeks) rats. In this paper, the results of dose fractionation are presented in relation to age at the time of irradiation. Young and older animals were irradiated with single and fractionated doses. After irradiation, rectal complications could lead to occlusion and stenosis, eventually resulting in the clinical symptoms of a megacolon and a possible fistula. For each dose group, cumulative survival rates were obtained with Kaplan-Meier analysis, from which dose-effect curves and the associated LD(50) values for a megacolon/fistula were calculated. The majority of responders died between 8 and 24 weeks after irradiation, irrespective of age. For both age groups, only the fractionation data showed a reduction in the mean latency with increasing dose. In the older age group, 39% of the responders developed a fistula compared to 26% for the younger animals. The LD(50) values increased from around 30 Gy after single doses to nearly 65 Gy after 10 fractions. The increases in LD(50) values with the number of fractions were independent of the age of the rats. For each of the dose fractionation schedules, log-rank testing indicated no significant differences in cumulative survival rates between younger and older animals (P > 0.10). The high alpha/beta ratios obtained for both the young and older animals strongly suggested that the late rectal complications were a consequence of early epithelial injury. Associated histological findings indicated that blood vessel damage, which was already evident at a high incidence at 4 weeks after irradiation

  14. Total dose hardness of a commercial SiGe BiCMOS technology

    International Nuclear Information System (INIS)

    Van Vonno, N.; Lucas, R.; Thornberry, D.

    1999-01-01

    Over the past decade SiGe HBT technology has progress from the laboratory to actual commercial applications. When integrated into a BiMOS process, this technology has applications in low-cost space systems. In this paper, we report results of total dose testing of a SiGe/CMOS process accessible through a commercial foundry. (authors)

  15. Worst-Case Bias During Total Dose Irradiation of SOI Transistors

    International Nuclear Information System (INIS)

    Ferlet-Cavrois, V.; Colladant, T.; Paillet, P.; Leray, J.-L; Musseau, O.; Schwank, James R.; Shaneyfelt, Marty R.; Pelloie, J.L.; Du Port de Poncharra, J.

    2000-01-01

    The worst case bias during total dose irradiation of partially depleted SOI transistors (from SNL and from CEA/LETI) is correlated to the device architecture. Experiments and simulations are used to analyze SOI back transistor threshold voltage shift and charge trapping in the buried oxide

  16. Recent Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

    Science.gov (United States)

    Cochran, Donna J.; Buchner, Stephen P.; Irwin, Tim L.; LaBel, Kenneth A.; Marshall, Cheryl J.; Reed, Robert A.; Sanders, Anthony B.; Hawkins, Donald K.; Flanigan, Ryan J.; Cox, Stephen R.

    2005-01-01

    We present data on the vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage. Devices tested include optoelectronics, digital, analog, linear bipolar devices, hybrid devices, Analog-to- Digital Converters (ADCs), and Digital-to-Analog Converters (DACs), among others. T

  17. Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology

    Science.gov (United States)

    Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; LaBel, K. A.

    2016-01-01

    Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the radiation design margin concept with one of failure probability during a mission.

  18. The influence of x-ray energy on lung dose uniformity in total-body irradiation

    International Nuclear Information System (INIS)

    Ekstrand, Kenneth; Greven, Kathryn; Wu Qingrong

    1997-01-01

    Purpose: In this study we examine the influence of x-ray energy on the uniformity of the dose within the lung in total-body irradiation treatments in which partial transmission blocks are used to control the lung dose. Methods and Materials: A solid water phantom with a cork insert to simulate a lung was irradiated by x-rays with energies of either 6, 10, or 18 MV. The source to phantom distance was 3.9 meters. The cork insert was either 10 cm wide or 6 cm wide. Partial transmission blocks with transmission factors of 50% were placed anterior to the cork insert. The blocks were either 8 or 4 cm in width. Kodak XV-2 film was placed in the midline of the phantom to record the dose. Midplane dose profiles were measured with a densitometer. Results: For the 10 cm wide cork insert the uniformity of the dose over 80% of the block width varied from 6.6% for the 6 MV x-rays to 12.2% for the 18 MV x-rays. For the 6 cm wide cork insert the uniformity was comparable for all three x-ray energies, but for 18 MV the central dose increased by 9.4% compared to the 10 cm wide insert. Conclusion: Many factors must be considered in optimizing the dose for total-body irradiation. This study suggests that for AP/PA techniques lung dose uniformity is superior with 6 MV irradiation. The blanket recommendation that the highest x-ray energy be used in TBI is not valid for all situations

  19. SU-E-T-357: Electronic Compensation Technique to Deliver Total Body Dose

    Energy Technology Data Exchange (ETDEWEB)

    Lakeman, T [State University of New York at Buffalo, Buffalo, NY (United States); Wang, I; Podgorsak, M [State University of New York at Buffalo, Buffalo, NY (United States); Roswell Park Cancer Institute, Buffalo, NY (United States)

    2015-06-15

    Purpose: Total body irradiation (TBI) uses large parallel-opposed radiation fields to suppress the patient’s immune system and eradicate the residual cancer cells in preparation of recipient for bone marrow transplant. The manual placement of lead compensators has conventionally been used to compensate for the varying thickness through the entire body in large-field TBI. The goal of this study is to pursue utilizing the modern electronic compensation technique to more accurately and efficiently deliver dose to patients in need of TBI. Methods: Treatment plans utilizing electronic compensation to deliver a total body dose were created retrospectively for patients for whom CT data had been previously acquired. Each treatment plan includes two, specifically weighted, pair of opposed fields. One pair of open, large fields (collimator=45°), to encompass the patient’s entire anatomy, and one pair of smaller fields (collimator=0°) focused only on the thicker midsection of the patient. The optimal fluence for each one of the smaller fields was calculated at a patient specific penetration depth. Irregular surface compensators provide a more uniform dose distribution within the smaller opposed fields. Results: Dose-volume histograms (DVH) were calculated for the evaluating the electronic compensation technique. In one case, the maximum body doses calculated from the DVH were reduced from the non-compensated 195.8% to 165.3% in the electronically compensated plans, indicating a more uniform dose with the region of electronic compensation. The mean body doses calculated from the DVH were also reduced from the non-compensated 120.6% to 112.7% in the electronically compensated plans, indicating a more accurate delivery of the prescription dose. All calculated monitor units were well within clinically acceptable limits. Conclusion: Electronic compensation technique for TBI will not substantially increase the beam on time while it can significantly reduce the compensator

  20. Effect of weight fraction of different constituent elements on the total ...

    Indian Academy of Sciences (India)

    The mass attenuation coefficients, µm, of biological materials have been ... increasing percentage of constituent elements in high energy region up to 10 MeV. ... Muscle. 72.89. Figure 1. Plot of µm (cm2/g) vs. hydrogen weight fraction at some ...

  1. Semisterility of the first male progeny of female rats given a fractionated x ray dose of 800 R with administration of cysteamine and cystamine

    Energy Technology Data Exchange (ETDEWEB)

    Baev, I; Bairakova, A

    1975-01-01

    A total of 107 male Wistar rats were obtained six months after the fractional irradiation of females at a total x ray dose of 800 R (40 R per day for 20 days). Part of the females were irradiated without protection, and the rest received 5 mg cysteamine and 20 mg cystamine per rat each day before irradiation. The irradiated females were crossed with intact males. Fifteen males obtained from unirradiated parents served as controls. Males obtained from irradiated mothers and the control males were each housed with 7 intact females on attaining reproductive age. The females were killed on the 18th day after fertilization, and the living and dead embryos and the yellow bodies in each female were determined. The embryonic lethality in the male progeny whose mothers were irradiated with a fractionated dose of 800 R was 11 percent preimplantation with 9 percent postimplantation for a total of 19 percent for irradiated mothers given no radioprotective agent compared with 7 percent preimplantation with 5.5 percent postimplantation for a total of 12.5 percent in the control rats. For the cystamine-protected mothers the corresponding embryonic lethalities were 16.1 percent preimplantation with 10.5 percent postimplantation for a total of 26.6 percent, and for the cysteamine protected mothers, 14.3 percent preimplantation with 14.2 percent postimplantation for a total of 28.5 percent. Abouthalf of the males from the first generation of irradiated females showed a lowered fertility. 10 refs.

  2. Influence of overall treatment time in a fractionated total lymphoid irradiation as an immunosuppressive therapy in allogeneic bone marrow transplantation in mice

    International Nuclear Information System (INIS)

    Waer, M.; Ang, K.K.; Vandeputte, M.; Van der Schueren, E.

    1982-01-01

    Three groups of C 57 /BL/Ka mice received total lymphoid irradiation (TLI) in a total dose of 34 Gy in three different fractionation schedules. The tolerance of all different schedules was excellent. No difference in the peripheral white blood cell and lymphocyte counts nor the degree of immunosuppression as measured by phytohaemaglutinin or concanavalin A induced blastogenesis and mixed lymphocyte reaction were observed at the end of the treatment and up to 200 days. When bone marrow transplantation was performed one day after the end of each schedule, chimerism without signs of graft versus host disease was induced in all the groups. However, from the results in a limited number of animals it seems that concentrated schedules were less effective for chimerism induction. It has been demonstrated that it is possible to reduce drastically the overall treatment time for TLI before bone marrow transplantation. Further investigations are necessary in order to determine the optimal time-dose-fractionation factors and the different perameters involved in the transplantation

  3. Estimation of the Arterial Fraction of Total Hepatic Flow from Radionuclide Angiogram Using 99mTc-DISIDA

    International Nuclear Information System (INIS)

    Lee, Hae Gin; Lim, Gye Yeon; Yang, Il Kwon; Kim, Hack Hee; Lim, Jung Ik; Bahk, Yong Whee; Han, Sok Won; Han, Nam Ik; Lee, Young Sok

    1991-01-01

    Arterial fraction of total hepatic blood flow was estimated by a new method, slope method, on radionuclide angiogram using 99m Tc-DISIDA and was compared with that from 99m Tc-Phytate radionuclide angiogram. This study included 11 of normal subjects, 37 of intermediate group with various liver diseases, and 25 patients with liver cirrhosis. We analyzed the data with slope method from radionuclide angiograms and the results were compared with hepatic arterial fractions from uptake method, introduced by Lee et al. at 1986. The hepatic arterial fractions from radionuclide angiograms using 99m Tc-DISIDA and 99m Tc- Phytate were 0.32 ± 0.09 and 0.31 ± 0.11 respectively in normal subjects, and 0.75 ± 0.18 and 0.77 ± 0.21 respectively in patients with liver cirrhosis. The hepatic arterial fractions by the slope method was well correlated with those of the uptake method on 99m Tc-DISIDA scan. There was high correlation between the hepatic arterial fractions from 99m Tc-DISIDA and 99m Tc-Phytate scans. Hepatic arterial fraction estimated by the slope method is a useful index for the diagnosis of liver cirrhosis and the evaluation of status of portal hypertension.

  4. Phase I/II trial of single-fraction high-dose-rate brachytherapy-boosted hypofractionated intensity-modulated radiation therapy for localized adenocarcinoma of the prostate.

    Science.gov (United States)

    Myers, Michael A; Hagan, Michael P; Todor, Dorin; Gilbert, Lynn; Mukhopadhyay, Nitai; Randolf, Jessica; Heimiller, Jeffrey; Anscher, Mitchell S

    2012-01-01

    A Phase I/II protocol was conducted to examine the toxicity and efficacy of the combination of intensity-modulated radiation therapy (IMRT) with a single-fraction high-dose-rate (HDR) brachytherapy implant. From 2001 through 2006, 26 consecutive patients were treated on the trial. The primary objective was to demonstrate a high rate of completion without experiencing a treatment-limiting toxicity. Eligibility was limited to patients with T stage ≤2b, prostate-specific antigen (PSA) ≤20, and Gleason score ≤7. Treatment began with a single HDR fraction of 6Gy to the entire prostate and 9Gy to the peripheral zone, followed by IMRT optimized to deliver in 28 fractions with a normalized total dose of 70Gy. Patients received 50.4Gy to the pelvic lymph node. The prostate dose (IMRT and HDR) resulted in an average biologic equivalent dose >128Gy (α/β=3). Patients whose pretreatment PSA was ≥10ng/mL, Gleason score 7, or stage ≥T2b received short-term androgen ablation. Median followup was 53 months (9-68 months). There were no biochemical failures by either the American Society of Therapeutic Radiology and Oncology or the Phoenix definitions. The median nadir PSA was 0.32ng/mL. All the 26 patients completed the treatment as prescribed. The rate of Grade 3 late genitourinary toxicity was 3.8% consisting of a urethral stricture. There was no other Grade 3 or 4 genitourinary or gastrointestinal toxicities. Single-fraction HDR-boosted IMRT is a safe effective method of dose escalation for localized prostate cancer. Copyright © 2012 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  5. Mutation induction in haploid yeast after split-dose radiation-exposure. I. Fractionated UV-irradiation.

    Science.gov (United States)

    Schenk, K; Zölzer, F; Kiefer, J

    1989-01-01

    Mutation induction was investigated in wild-type haploid yeast Saccharomyces cerevisiae after split-dose UV-irradiation. Cells were exposed to fractionated 254 nm-UV-doses separated by intervals from 0 to 6 h with incubation either on non-nutrient or nutrient agar between. The test parameter was resistance to canavanine. If modifications of sensitivity due to incubation are appropriately taken into account there is no change of mutation frequency.

  6. Time- and dose-dependent effects of total-body ionizing radiation on muscle stem cells

    Science.gov (United States)

    Masuda, Shinya; Hisamatsu, Tsubasa; Seko, Daiki; Urata, Yoshishige; Goto, Shinji; Li, Tao-Sheng; Ono, Yusuke

    2015-01-01

    Exposure to high levels of genotoxic stress, such as high-dose ionizing radiation, increases both cancer and noncancer risks. However, it remains debatable whether low-dose ionizing radiation reduces cellular function, or rather induces hormetic health benefits. Here, we investigated the effects of total-body γ-ray radiation on muscle stem cells, called satellite cells. Adult C57BL/6 mice were exposed to γ-radiation at low- to high-dose rates (low, 2 or 10 mGy/day; moderate, 50 mGy/day; high, 250 mGy/day) for 30 days. No hormetic responses in proliferation, differentiation, or self-renewal of satellite cells were observed in low-dose radiation-exposed mice at the acute phase. However, at the chronic phase, population expansion of satellite cell-derived progeny was slightly decreased in mice exposed to low-dose radiation. Taken together, low-dose ionizing irradiation may suppress satellite cell function, rather than induce hormetic health benefits, in skeletal muscle in adult mice. PMID:25869487

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

    International Nuclear Information System (INIS)

    Gossman, Michael S.; Sharma, Subhash C.

    2004-01-01

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

  8. Total dose hardening of buried insulator in implanted silicon-on-insulator structures

    International Nuclear Information System (INIS)

    Mao, B.Y.; Chen, C.E.; Pollack, G.; Hughes, H.L.; Davis, G.E.

    1987-01-01

    Total dose characteristics of the buried insulator in implanted silicon-on-insulator (SOI) substrates have been studied using MOS transistors. The threshold voltage shift of the parasitic back channel transistor, which is controlled by charge trapping in the buried insulator, is reduced by lowering the oxygen dose as well as by an additional nitrogen implant, without degrading the front channel transistor characteristics. The improvements in the radiation characteristics of the buried insulator are attributed to the decrease in the buried oxide thickness or to the presence of the interfacial oxynitride layer formed by the oxygen and nitrogen implants

  9. Preliminary Results of a Phase 1 Dose-Escalation Trial for Early-Stage Breast Cancer Using 5-Fraction Stereotactic Body Radiation Therapy for Partial-Breast Irradiation

    International Nuclear Information System (INIS)

    Rahimi, Asal; Thomas, Kimberly; Spangler, Ann; Rao, Roshni; Leitch, Marilyn; Wooldridge, Rachel; Rivers, Aeisha; Seiler, Stephen; Albuquerque, Kevin; Stevenson, Stella; Goudreau, Sally; Garwood, Dan; Haley, Barbara; Euhus, David; Heinzerling, John; Ding, Chuxiong; Gao, Ang; Ahn, Chul; Timmerman, Robert

    2017-01-01

    Purpose: To evaluate the tolerability of a dose-escalated 5-fraction stereotactic body radiation therapy for partial-breast irradiation (S-PBI) in treating early-stage breast cancer after partial mastectomy; the primary objective was to escalate dose utilizing a robotic stereotactic radiation system treating the lumpectomy cavity without exceeding the maximum tolerated dose. Methods and Materials: Eligible patients included those with ductal carcinoma in situ or invasive nonlobular epithelial histologies and stage 0, I, or II, with tumor size <3 cm. Patients and physicians completed baseline and subsequent cosmesis outcome questionnaires. Starting dose was 30 Gy in 5 fractions and was escalated by 2.5 Gy total for each cohort to 40 Gy. Results: In all, 75 patients were enrolled, with a median age of 62 years. Median follow-up for 5 cohorts was 49.9, 42.5, 25.7, 20.3, and 13.5 months, respectively. Only 3 grade 3 toxicities were experienced. There was 1 dose-limiting toxicity in the overall cohort. Ten patients experienced palpable fat necrosis (4 of which were symptomatic). Physicians scored cosmesis as excellent or good in 95.9%, 100%, 96.7%, and 100% at baseline and 6, 12, and 24 months after S-PBI, whereas patients scored the same periods as 86.5%, 97.1%, 95.1%, and 95.3%, respectively. The disagreement rates between MDs and patients during those periods were 9.4%, 2.9%, 1.6%, and 4.7%, respectively. There have been no recurrences or distant metastases. Conclusion: Dose was escalated to the target dose of 40 Gy in 5 fractions, with the occurrence of only 1 dose-limiting toxicity. Patients felt cosmetic results improved within the first year after surgery and stereotactic body radiation therapy. Our results show minimal toxicity with excellent cosmesis; however, further follow-up is warranted in future studies. This study is the first to show the safety, tolerability, feasibility, and cosmesis results of a 5-fraction dose-escalated S-PBI treatment for

  10. Preliminary Results of a Phase 1 Dose-Escalation Trial for Early-Stage Breast Cancer Using 5-Fraction Stereotactic Body Radiation Therapy for Partial-Breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Asal, E-mail: asal.rahimi@utsouthwestern.edu [University of Texas Southwestern Medical Center, Dallas, Texas (United States); Thomas, Kimberly; Spangler, Ann [University of Texas Southwestern Medical Center, Dallas, Texas (United States); Rao, Roshni; Leitch, Marilyn; Wooldridge, Rachel; Rivers, Aeisha [Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Seiler, Stephen [Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Albuquerque, Kevin; Stevenson, Stella [University of Texas Southwestern Medical Center, Dallas, Texas (United States); Goudreau, Sally [Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Garwood, Dan [University of Texas Southwestern Medical Center, Dallas, Texas (United States); Haley, Barbara [Department of Medical Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Euhus, David [Department of Surgery, Johns Hopkins University, Baltimore, Maryland (United States); Heinzerling, John [Department of Radiation Oncology, Levine Cancer Institute, Charlotte, North Carolina (United States); Ding, Chuxiong [University of Texas Southwestern Medical Center, Dallas, Texas (United States); Gao, Ang; Ahn, Chul [Department of Statistics, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Timmerman, Robert [University of Texas Southwestern Medical Center, Dallas, Texas (United States)

    2017-05-01

    Purpose: To evaluate the tolerability of a dose-escalated 5-fraction stereotactic body radiation therapy for partial-breast irradiation (S-PBI) in treating early-stage breast cancer after partial mastectomy; the primary objective was to escalate dose utilizing a robotic stereotactic radiation system treating the lumpectomy cavity without exceeding the maximum tolerated dose. Methods and Materials: Eligible patients included those with ductal carcinoma in situ or invasive nonlobular epithelial histologies and stage 0, I, or II, with tumor size <3 cm. Patients and physicians completed baseline and subsequent cosmesis outcome questionnaires. Starting dose was 30 Gy in 5 fractions and was escalated by 2.5 Gy total for each cohort to 40 Gy. Results: In all, 75 patients were enrolled, with a median age of 62 years. Median follow-up for 5 cohorts was 49.9, 42.5, 25.7, 20.3, and 13.5 months, respectively. Only 3 grade 3 toxicities were experienced. There was 1 dose-limiting toxicity in the overall cohort. Ten patients experienced palpable fat necrosis (4 of which were symptomatic). Physicians scored cosmesis as excellent or good in 95.9%, 100%, 96.7%, and 100% at baseline and 6, 12, and 24 months after S-PBI, whereas patients scored the same periods as 86.5%, 97.1%, 95.1%, and 95.3%, respectively. The disagreement rates between MDs and patients during those periods were 9.4%, 2.9%, 1.6%, and 4.7%, respectively. There have been no recurrences or distant metastases. Conclusion: Dose was escalated to the target dose of 40 Gy in 5 fractions, with the occurrence of only 1 dose-limiting toxicity. Patients felt cosmetic results improved within the first year after surgery and stereotactic body radiation therapy. Our results show minimal toxicity with excellent cosmesis; however, further follow-up is warranted in future studies. This study is the first to show the safety, tolerability, feasibility, and cosmesis results of a 5-fraction dose-escalated S-PBI treatment for

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

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, Kai; Elsayad, Khaled; Moustakis, Christos; Haverkamp, Uwe; Eich, Hans Theodor [University Hospital of Muenster, Department of Radiation Oncology, Muenster (Germany)

    2017-12-15

    Low-dose total skin electron beam therapy (TSEBT) is attracting increased interest for the effective palliative treatment of primary cutaneous T-cell lymphoma (pCTCL). In this study, we compared toxicity profiles following various radiation doses. We reviewed the records of 60 patients who underwent TSEBT for pCTCL between 2000 and 2016 at the University Hospital of Munster. The treatment characteristics of the radiotherapy (RT) regimens and adverse events (AEs) were then analyzed and compared. In total, 67 courses of TSEBT were administered to 60 patients. Of these patients, 34 (51%) received a standard dose with a median surface dose of 30 Gy and 33 patients (49%) received a low dose with the median surface dose of 12 Gy (7 salvage low-dose TSEBT courses were administered to 5 patients). After a median follow-up of 15 months, the overall AE rate was 100%, including 38 patients (57%) with grade 2 and 7 (10%) with grade 3 AEs. Patients treated with low-dose TSEBT had significantly fewer grade 2 AEs than those with conventional dose regimens (33 vs. 79%, P < 0.001). A lower grade 3 AE rate was also observed in patients who had received the low-dose regimen compared to those with the conventional dose regimens (6 vs. 15%, P = 0.78). Multiple/salvage low-dose TSEBT courses were not associated with an increased risk of acute AEs. Low-dose TSEBT regimens are associated with significantly fewer grade 2 acute toxicities compared with conventional doses of TSEBT. Repeated/Salvage low-dose TSEBT, however, appears to be tolerable and can even be applied safely in patients with cutaneous relapses. (orig.) [German] Eine niedrigdosierte Ganzhautelektronenbestrahlung (TSEBT) wird vermehrt zur effektiven palliativen Behandlung von Patienten mit primaer kutanen T-Zell-Lymphomen (pCTCL) eingesetzt. In dieser Studie vergleichen wir die Toxizitaetsprofile verschiedener Dosiskonzepte. Untersucht wurden 60 zwischen 2000 und 2016 am Universitaetsklinikum Muenster mittels TSEBT

  12. Measurement with total scatter calibrate factor at different depths in the calculation of prescription dose

    International Nuclear Information System (INIS)

    Li Lijun; Zhu Haijun; Zhang Xinzhong; Li Feizhou; Song Hongyu

    2004-01-01

    Objective: To evaluate the method of measurement of total scatter calibrate factor (Sc, p). Methods: To measure the Sc, p at different depths on central axis of 6MV, 15MV photon beams through different ways. Results: It was found that the measured data of Sc, p changed with the different depths to a range of 1% - 7%. Using the direct method, the Sc, p measured depth should be the same as the depth in dose normalization point of the prescription dose. If the Sc, p (fsz, d) was measured at the other depths, it could be obtained indirectly by the calculation formula. Conclusions: The Sc, p in the prescription dose can be obtained either by the direct measure method or the indirect calculation formula. But emphasis should be laid on the proper measure depth. (authors)

  13. Optimization of the fractionated irradiation scheme considering physical doses to tumor and organ at risk based on dose–volume histograms

    Energy Technology Data Exchange (ETDEWEB)

    Sugano, Yasutaka [Graduate School of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan); Mizuta, Masahiro [Laboratory of Advanced Data Science, Information Initiative Center, Hokkaido University, Kita-11, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0811 (Japan); Takao, Seishin; Shirato, Hiroki; Sutherland, Kenneth L. [Department of Radiation Medicine, Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Date, Hiroyuki, E-mail: date@hs.hokudai.ac.jp [Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan)

    2015-11-15

    Purpose: Radiotherapy of solid tumors has been performed with various fractionation regimens such as multi- and hypofractionations. However, the ability to optimize the fractionation regimen considering the physical dose distribution remains insufficient. This study aims to optimize the fractionation regimen, in which the authors propose a graphical method for selecting the optimal number of fractions (n) and dose per fraction (d) based on dose–volume histograms for tumor and normal tissues of organs around the tumor. Methods: Modified linear-quadratic models were employed to estimate the radiation effects on the tumor and an organ at risk (OAR), where the repopulation of the tumor cells and the linearity of the dose-response curve in the high dose range of the surviving fraction were considered. The minimization problem for the damage effect on the OAR was solved under the constraint that the radiation effect on the tumor is fixed by a graphical method. Here, the damage effect on the OAR was estimated based on the dose–volume histogram. Results: It was found that the optimization of fractionation scheme incorporating the dose–volume histogram is possible by employing appropriate cell surviving models. The graphical method considering the repopulation of tumor cells and a rectilinear response in the high dose range enables them to derive the optimal number of fractions and dose per fraction. For example, in the treatment of prostate cancer, the optimal fractionation was suggested to lie in the range of 8–32 fractions with a daily dose of 2.2–6.3 Gy. Conclusions: It is possible to optimize the number of fractions and dose per fraction based on the physical dose distribution (i.e., dose–volume histogram) by the graphical method considering the effects on tumor and OARs around the tumor. This method may stipulate a new guideline to optimize the fractionation regimen for physics-guided fractionation.

  14. Determination of serum free thyroxine concentration (FT4) by means of fT4-fraction and total thyroxine concentration

    International Nuclear Information System (INIS)

    Passath, A.; Leb, G.

    1985-01-01

    A new equilibrium assay for the determination of serum free thyroxine was evaluated in 514 patients. The assay comprises a two-vial-procedure to measure total thyroxine and free thyroxine fraction by use of monoclonal antibodies. Free thyroxine concentrations are calculated from fT 4 -fraction and total thyroxine concentration readings. In euthyroidism the average free thyroxine fraction (%fT 4 ) was 0.011%, in hyperthyroidism this fraction was elevated, in hypothyroidism it was below normal. In patients with TBG anomalies, TBG values were inversely correlated with fT 4 fraction readings. The 'euthyroid reference range' of FT 4 (SPAC ET) was between 0.70 to 1.78ng/dl. This euthyroid range of FT 4 was determined from TT 4 concentrations measured by T 4 -RIA (SPAC T 4 MONO) which were 30% above TT 4 values measured by conventional T 4 -RIA (SPAC T 4 POLY; polyclonal antibodies). However, a different euthyroid range of FT 4 between 0.55 to 1.30 ng/dl was observed as well as by other investigators when conventional T 4 -RIA measurements were used for calculation of FT 4 values. Our results indicate that calculated FT 4 concentration values are highly dependent on the methods used for determination of total thyroxine concentrations. Precision and reproducability of this two vial equilibrium assay did not meet the requirements mandatory for the application as a clinical routine diagnostic procedure, and its general use for this purpose can as yet not be recommended. (Author)

  15. The Role of Electron Transport and Trapping in MOS Total-Dose Modeling

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Winokur, P.S.; Riewe, L.C.; Flament, O.; Paillet, P.; Leray, J.L.

    1999-01-01

    Radiation-induced hole and electron transport and trapping are fundamental to MOS total-dose models. Here we separate the effects of electron-hole annihilation and electron trapping on the neutralization of radiation-induced charge during switched-bias irradiation for hard and soft oxides, via combined thermally stimulated current (TSC) and capacitance-voltage measurements. We also show that present total-dose models cannot account for the thermal stability of deeply trapped electrons near the Si/SiO 2 interface, or the inability of electrons in deep or shallow traps to contribute to TSC at positive bias following (1) room-temperature, (2) high-temperature, or (3) switched-bias irradiation. These results require revisions of modeling parameters and boundary conditions for hole and electron transport in SiO 2 . The nature of deep and shallow electron traps in the near-interfacial SiO 2 is discussed

  16. Revisiting Low-Dose Total Skin Electron Beam Therapy in Mycosis Fungoides

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Cameron, E-mail: cameronh@stanford.edu [Department of Dermatology, Stanford Cancer Center, Stanford, California (United States); Young, James; Navi, Daniel [Department of Dermatology, Stanford Cancer Center, Stanford, California (United States); Riaz, Nadeem [Department of Radiation Oncology, Stanford Cancer Center, Stanford, California (United States); Lingala, Bharathi; Kim, Youn [Department of Dermatology, Stanford Cancer Center, Stanford, California (United States); Hoppe, Richard [Department of Radiation Oncology, Stanford Cancer Center, Stanford, California (United States)

    2011-11-15

    Purpose: Total skin electron beam therapy (TSEBT) is a highly effective treatment for mycosis fungoides (MF). The standard course consists of 30 to 36 Gy delivered over an 8- to 10-week period. This regimen is time intensive and associated with significant treatment-related toxicities including erythema, desquamation, anhydrosis, alopecia, and xerosis. The aim of this study was to identify a lower dose alternative while retaining a favorable efficacy profile. Methods and Materials: One hundred two MF patients were identified who had been treated with an initial course of low-dose TSEBT (5-<30 Gy) between 1958 and 1995. Patients had a T stage classification of T2 (generalized patch/plaque, n = 51), T3 (tumor, n = 29), and T4 (erythrodermic, n = 22). Those with extracutaneous disease were excluded. Results: Overall response (OR) rates (>50% improvement) were 90% among patients with T2 to T4 disease receiving 5 to <10 Gy (n = 19). In comparison, OR rates between the 10 to <20 Gy and 20 to <30 Gy subgroups were 98% and 97%, respectively. There was no significant difference in median progression free survival (PFS) in T2 and T3 patients when stratified by dose group, and PFS in each was comparable to that of the standard dose. Conclusions: OR rates associated with low-dose TSEBT in the ranges of 10 to <20 Gy and 20 to <30 Gy are comparable to that of the standard dose ({>=} 30 Gy). Efficacy measures including OS, PFS, and RFS are also favorable. Given that the efficacy profile is similar between 10 and <20 Gy and 20 and <30 Gy, the utility of TSEBT within the lower dose range of 10 to <20 Gy merits further investigation, especially in the context of combined modality treatment.

  17. Total dose induced latch in short channel NMOS/SOI transistors

    International Nuclear Information System (INIS)

    Ferlet-Cavrois, V.; Quoizola, S.; Musseau, O.; Flament, O.; Leray, J.L.; Pelloie, J.L.; Raynaud, C.; Faynot, O.

    1998-01-01

    A latch effect induced by total dose irradiation is observed in short channel SOI transistors. This effect appears on NMOS transistors with either a fully or a partially depleted structure. It is characterized by a hysteresis behavior of the Id-Vg characteristics at high drain bias for a given critical dose. Above this dose, the authors still observe a limited leakage current at low drain bias (0.1 V), but a high conduction current at high drain bias (2 V) as the transistor should be in the off-state. The critical dose above which the latch appears strongly depends on gate length, transistor structure (fully or partially depleted), buried oxide thickness and supply voltage. Two-dimensional (2D) numerical simulations indicate that the parasitic condition is due to the latch of the back gate transistor triggered by charge trapping in the buried oxide. To avoid the latch induced by the floating body effect, different techniques can be used: doping engineering, body contacts, etc. The study of the main parameters influencing the latch (gate length, supply voltage) shows that the scaling of technologies does not necessarily imply an increased latch sensitivity. Some technological parameters like the buried oxide hardness and thickness can be used to avoid latch, even at high cumulated dose, on highly integrated SOI technologies

  18. Test methods of total dose effects in very large scale integrated circuits

    International Nuclear Information System (INIS)

    He Chaohui; Geng Bin; He Baoping; Yao Yujuan; Li Yonghong; Peng Honglun; Lin Dongsheng; Zhou Hui; Chen Yusheng

    2004-01-01

    A kind of test method of total dose effects (TDE) is presented for very large scale integrated circuits (VLSI). The consumption current of devices is measured while function parameters of devices (or circuits) are measured. Then the relation between data errors and consumption current can be analyzed and mechanism of TDE in VLSI can be proposed. Experimental results of 60 Co γ TDEs are given for SRAMs, EEPROMs, FLASH ROMs and a kind of CPU

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  20. Compliance to the prescribed dose and overall treatment time in five randomized clinical trials of altered fractionation in radiotherapy for head-and-neck carcinomas

    International Nuclear Information System (INIS)

    Khalil, Azza A.; Bentzen, Soeren M.; Bernier, Jacques; Saunders, Michele I.; Horiot, Jean-Claude; Bogaert, Walter van den; Cummings, Bernard J.; Dische, Stanley

    2003-01-01

    Purpose: To investigate compliance to the prescribed dose-fractionation schedule in five randomized controlled trials of altered fractionation in radiotherapy for head-and-neck carcinoma. Methods and Materials: Individual patient data from 2566 patients participating in the European Organization for Research and Treatment of Cancer (EORTC) 22791, EORTC 22811, EORTC 22851, Princess Margaret Hospital (PMH), and continuous hyperfractionated accelerated radiotherapy (CHART) head-and-neck trials were merged in the fractionation IMPACT (Intergroup Merger of Patient data from Altered or Conventional Treatment schedules) study database. The ideal treatment time was defined as the minimum time required to deliver a prescribed schedule. Compliance to the prescribed overall treatment time was quantified as the difference between the actual and the ideal overall time. An overall measure of compliance in an individual patient, the total dose lost (TDL), was calculated as the dose lost due to prolongation of therapy (assuming a D prolif of 0.64 Gy/day) plus the difference between the prescribed and the actual dose given. Results: The time in excess of the ideal ranged up to 97 days (average 3.9 days), and 25% of the patients had delays of 6 days or more. World Health Organization (WHO) performance status and nodal stage had a significant effect on TDL. TDL was significantly higher in the conventional than in the altered arm of the EORTC 22851 and CHART trials. In the PMH trial, TDL was significantly higher in the hyperfractionation than in the conventional arm. Centers participating in the three EORTC trials varied significantly in their compliance. There was a significant improvement in compliance in patients treated more recently. Conclusions: Even in randomized controlled trials, compliance to the prescribed radiation therapy schedule may be relatively poor, especially after conventional fractionation. This affects the interpretation of the outcome of these trials

  1. Role of Immunomodulators in Tumor Regression in Mice Exposed to Fractionated Low Dose of Gamma Radiation

    International Nuclear Information System (INIS)

    Rokaya Elsayed Maaroaf Elsayed

    2015-01-01

    Immunotherapy is one of the most promising approaches of cancer treatment. The present study was designed to examine the role of irradiated tumor cell lysate vaccine, IFNα-2b and low dose of gamma irradiation as immunomodulators either alone or combined in tumor regression. Ehrlich ascite carcinoma (EAC) cells and 9 groups of female mice were used. Mice were immunized intramuscularly by tumor cell lysate vaccine one time/week for 3 weeks in the right thigh of mice. After two weeks from last immunization, all mice were challenged with normal viable EAC cells at count of 2.5 ×10 6 /mouse in the opposite left thigh for Ehrlich carcinoma (EC) production. Mice were subcutaneously injected with 10.000 units of IFNα-2b 3 times/week for 4 weeks and others were exposed to fractionated dose of γ- radiation (0.5 Gy/day x 4, day after day). Tumor size, serum tumor markers (TNF-α and CEA), tumor DNA fragmentation and Caspase-3 were evaluated. Oxidative stress (MDA and NO) markers and antioxidants (GSH, GPX and SOD) were determined in spleen and tumor tissues. Histopathological examinations, apoptosis and necrosis in spleen and tumor tissues were also examined. The results revealed significant inhibition in tumor size throughout the observation period either for treatments with vaccine or IFNα-2b either alone or combined with γ-irradiation. DNA fragmentation and Caspase-3 enzyme activities were significantly elevated in immunized mice as compared with EC group along with diminished tumor size while, tumor markers were significantly decreased. MDA and NO were significantly increased in tumor tissue.while, tumor GSH content, GPX and SOD activities were significantly decreased. Combined treatments of female mice bearing EC with IFN-α-2b, tumor cell lysate vaccine and low dose of γ-radiation cause a highly significant decrease in serum TNF-α and CEA levels, increase in Cas-3 activity, no DNA fragmentation, significant increase in MDA, decrease in SOD activity and decreased

  2. The effect of fractionating 100 R hard X-ray doses on the hemogram and proteinogram of the rabbit

    International Nuclear Information System (INIS)

    Alix, D.

    1965-01-01

    Eighty one rabbits 'Fauve de Bourgogne' received total exposure of 100 R X-rays, by fractional doses of 5 - 10 - 25 - 50 and 100 R per irradiation. Blood count and protein dosage were practised before, during and after the irradiation session. Seventeen controls were subjected to the same investigations with the same periodicity. Statistical analysis of experimental data permitted to infer from the exposures of X-rays, that irradiation induces drop in leucocytes count, resulting from a drop in mononuclear cells. On the other hand, it is more difficult to clear up its action on the protein profiles, because the observed changes were likewise observed on the controls, although at a lesser degree. Nevertheless, the authors think that it may be concluded to an increase of albumin concentration and to some instability of the gamma-globulins concentration. Then they discuss the possible mechanisms of X-rays effects: either perturbations of protean metabolism following loss of mitotic activity or histolysis. (author) [fr

  3. Patterns of Local Recurrence and Dose Fractionation of Adjuvant Radiation Therapy in 462 Patients With Soft Tissue Sarcoma of Extremity and Trunk Wall

    Energy Technology Data Exchange (ETDEWEB)

    Jebsen, Nina L., E-mail: nina.louise.jebsen@helse-bergen.no [Department of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen (Norway); Department of Oncology, Haukeland University Hospital, Bergen (Norway); Engellau, Jacob [Department of Oncology, Skåne University Hospital, Lund (Sweden); Engström, Katarina [Department of Oncology, Sahlgrenska University Hospital, Gothenburg (Sweden); Bauer, Henrik C. [Department of Molecular Medicine and Surgery, Section for Orthopaedics and Sports Medicine, Karolinska University Hospital, Karolinska Institute, Stockholm (Sweden); Monge, Odd R. [Department of Oncology, Haukeland University Hospital, Bergen (Norway); Muren, Ludvig P. [Department of Physics and Technology, University of Bergen, Bergen (Norway); Department of Medical Physics, Aarhus University and Aarhus University Hospital, Aarhus (Denmark); Eide, Geir E. [Centre for Clinical Research, Haukeland University Hospital, Bergen (Norway); Department of Public Health and Primary Health Care, University of Bergen, Bergen (Norway); Trovik, Clement S. [Department of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen (Norway); Department of Oncology, Haukeland University Hospital, Bergen (Norway); Bruland, Øyvind S. [Department of Oncology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway)

    2013-08-01

    Purpose: To study the impact of dose fractionation of adjuvant radiation therapy (RT) on local recurrence (LR) and the relation of LR to radiation fields. Methods and Materials: LR rates were analyzed in 462 adult patients with soft tissue sarcoma who underwent surgical excision and adjuvant RT at five Scandinavian sarcoma centers from 1998 to 2009. Medical records were reviewed for dose fractionation parameters and to determine the location of the LR relative to the radiation portals. Results: Fifty-five of 462 patients developed a LR (11.9%). Negative prognostic factors included intralesional surgical margin (hazard ratio [HR]: 7.83, 95% confidence interval [CI]: 3.08-20.0), high malignancy grade (HR: 5.82, 95% CI: 1.31-25.8), age at diagnosis (HR per 10 years: 1.27, 95% CI: 1.03-1.56), and malignant peripheral nerve sheath tumor histological subtype (HR: 6.66, 95% CI: 2.56-17.3). RT dose was tailored to margin status. No correlation between RT dose and LR rate was found in multiple Cox regression analysis. The majority (65%) of LRs occurred within the primary RT volume. Conclusions: No significant dose–response effect of adjuvant RT was demonstrated. Interestingly, patients given 45-Gy accelerated RT (1.8 Gy twice daily/2.5 weeks) had the best local outcome. A total dose of 50 Gy in 25 fractions seemed adequate following wide margin surgery. The risk of LR was associated with histopathologic subtype, which should be included in the treatment algorithm of adjuvant RT in soft tissue sarcoma.

  4. Patterns of Local Recurrence and Dose Fractionation of Adjuvant Radiation Therapy in 462 Patients With Soft Tissue Sarcoma of Extremity and Trunk Wall

    International Nuclear Information System (INIS)

    Jebsen, Nina L.; Engellau, Jacob; Engström, Katarina; Bauer, Henrik C.; Monge, Odd R.; Muren, Ludvig P.; Eide, Geir E.; Trovik, Clement S.; Bruland, Øyvind S.

    2013-01-01

    Purpose: To study the impact of dose fractionation of adjuvant radiation therapy (RT) on local recurrence (LR) and the relation of LR to radiation fields. Methods and Materials: LR rates were analyzed in 462 adult patients with soft tissue sarcoma who underwent surgical excision and adjuvant RT at five Scandinavian sarcoma centers from 1998 to 2009. Medical records were reviewed for dose fractionation parameters and to determine the location of the LR relative to the radiation portals. Results: Fifty-five of 462 patients developed a LR (11.9%). Negative prognostic factors included intralesional surgical margin (hazard ratio [HR]: 7.83, 95% confidence interval [CI]: 3.08-20.0), high malignancy grade (HR: 5.82, 95% CI: 1.31-25.8), age at diagnosis (HR per 10 years: 1.27, 95% CI: 1.03-1.56), and malignant peripheral nerve sheath tumor histological subtype (HR: 6.66, 95% CI: 2.56-17.3). RT dose was tailored to margin status. No correlation between RT dose and LR rate was found in multiple Cox regression analysis. The majority (65%) of LRs occurred within the primary RT volume. Conclusions: No significant dose–response effect of adjuvant RT was demonstrated. Interestingly, patients given 45-Gy accelerated RT (1.8 Gy twice daily/2.5 weeks) had the best local outcome. A total dose of 50 Gy in 25 fractions seemed adequate following wide margin surgery. The risk of LR was associated with histopathologic subtype, which should be included in the treatment algorithm of adjuvant RT in soft tissue sarcoma

  5. Randomized multicenter follow-up trial on the effect of radiotherapy for plantar fasciitis (painful heels spur) depending on dose and fractionation – a study protocol

    International Nuclear Information System (INIS)

    Holtmann, Henrik; Niewald, Marcus; Prokein, Benjamin; Graeber, Stefan; Ruebe, Christian

    2015-01-01

    An actual clinical trial showed the effect of low dose radiotherapy in painful heel spur (plantar fasciitis) with single doses of 1.0 Gy and total doses of 6.0 Gy applied twice weekly. Furthermore, a lot of animal experimental and in vitro data reveals the effect of lower single doses of 0.5 Gy which may be superior in order to ease pain and reduce inflammation in patients with painful heel spur. Our goal is therefore to transfer this experimentally found effect into a randomized multicenter trial. This was a controlled, prospective, two-arm phase III-multicenter trial. The standard arm consisted of single fractions of 1.0 Gy applied two times a week, for a total dose of 6.0 Gy (total therapy time: 3 weeks). The experimental arm consisted of single fractions of 0.5 Gy applied 3 times a week, for a total dose of 6.0 Gy (total therapy time: 4 weeks). Following a statistical power calculation, there were 120 patients for each investigation arm. The main inclusion criteria were: age > = 40 years, clinical and radiologically diagnosed painful heel spur (plantar fasciitis), and current symptoms for at least 6 months. The main exclusion criteria were: former local trauma, surgery or radiotherapy of the heel; pregnant or breastfeeding women; and a pre-existing severe psychiatric or psychosomatic disorder. After approving a written informed consent the patients are randomized by a statistician into one of the trial arms. After radiotherapy, the patients are seen after six weeks, after twelve weeks and then every twelve weeks up to 48 weeks. Additionally, they receive a questionnaire every six weeks after the follow-up examinations up to 48 weeks. The effect is measured using the visual analogue scale of pain (VAS), the calcaneodynia score according to Rowe and the SF-12 score. The primary endpoint is the pain relief three months after therapy. Patients of both therapy arms with an insufficient result are offered a second radiotherapy series applying the standard dose

  6. Hyperfractionated high-dose total body irradiation in bone marrow transplantation for Ph{sup 1}-positive acute lymphoblastic leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Akira; Ebihara, Yasuhiro; Mitsui, Tetsuo [Tokyo Univ. (Japan). Hospital of the Institute of Medical Science] [and others

    1998-12-01

    In two cases of Philadelphia-positive childhood acute lymphoblastic leukemia (Ph{sup 1} ALL), we performed allogeneic bone marrow transplantation (AlloBMT) with preconditioning regimen, including hyperfractionated high-dose total body irradiation (TBI) (13.5 Gy, in 9 fractions). Their disease statuses at BMT were hematological relapse in case 1 and molecular relapse in case 2. Bone marrow donors were unrelated in case 1, and HLA was a partially mismatched mother in case 2. Regimen-related toxicity was tolerable in both cases. Hematological recovery was rapid, and engraftment was obtained on day 14 in case 1 and on day 12 in case 2. BCR/ABL message in bone marrow disappeared on day 89 in case 1 and on day 19 in case 2 and throughout their subsequent clinical courses. Although short-term MTX and Cy-A continuous infusion were used for GVHD prophylaxis, grade IV GVHD was observed in case 1 and grade III in case 2. Both cases experienced hemorrhagic cystitis because of adenovirus type 11 infection. Although case 1 died of interstitial pneumonitis on day 442, case 2 has been free of disease through day 231. AlloBMT for Ph{sup 1} ALL with preconditioning regimen including hyperfractionated high-dose TBI is considered to be worth further investigation. (author)

  7. Compositional features of cotton plant biomass fractions characterized by attenuated total reflection Fourier transform infrared spectroscopy

    Science.gov (United States)

    Cotton is one of the most important and widely grown crops in the world. In addition to natural textile fiber production as a primary purpose, it yields a high grade vegetable oil for human consumption and also carbohydrate fiber and protein byproducts for animal feed. In this work, attenuated total...

  8. Effect of e-beam dose on the fractional density of Au-catalyzed GaAs nanowire growth

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeung Hun, E-mail: jeunghunpark@gmail.com [Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095 (United States); Gambin, Vincent [Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 (United States); Kodambaka, Suneel, E-mail: kodambaka@ucla.edu [Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095 (United States)

    2016-05-31

    Using Au/GaAs as a model system, the effect of initial catalyst patterning conditions on the growth of nanowire was studied. Resulting morphologies and fractional surface densities are determined as a function of e-beam dose, dot size, and inter-dot spacing using scanning and transmission electron microscopies. The majority of resulting nanowires grow randomly oriented with respect to the substrate. The nanowires are tapered with narrow tops, wider bases, and catalysts at the wire tips — characteristics of vapor–liquid–solid process. The base diameters of the wires are larger than the dot size, which is likely due to the non-catalyzed vapor–solid deposition along the sidewalls. The higher dose rate used in pattering leads to the formation of higher aspect ratio nanowires with narrower bases. The fractional surface density is found to increase linearly with the clearing dose and the critical dose for nanowire growth increases with decreasing catalyst pattern size and spacing. At a given dose, the fractional density increases with increasing Au dot size and with decreasing inter-dot spacing. Our results may provide new insights into the role of catalyst preparing conditions on the high density, wafer-scale growth of nanowires. - Highlights: • Initial Au catalyst layers are prepared using electron beam lithography. • GaAs nanowires are grown on GaAs(111)B using molecular beam epitaxy. • Effect of dose, size and spacing of Au dots on morphology and density is studied. • Density of nanowires is controlled by changing exposed dose on Au catalyst.

  9. The Sandia total-dose estimator: SANDOSE description and user guide

    International Nuclear Information System (INIS)

    Turner, C.D.

    1995-02-01

    The SANdia total-DOSe Estimator (SANDOSE) is used to estimate total radiation dose to a (BRL-CAT) solid model, SANDOSE uses the mass-sectoring technique to sample the model using ray-tracing techniques. The code is integrated directly into the BRL-CAD solid model editor and is operated using a simple graphical user interface. Several diagnostic tools are available to allow the user to analyze the results. Based on limited validation using several benchmark problems, results can be expected to fall between a 10% underestimate and a factor of 2 overestimate of the actual dose predicted by rigorous radiation transport techniques. However, other situations may be encountered where the results might fall outside of this range. The code is written in C and uses X-windows graphics. It presently runs on SUN SPARCstations, but in theory could be ported to any workstation with a C compiler and X-windows. SANDOSE is available via license by contacting either the Sandia National Laboratories Technology Transfer Center or the author

  10. Quality assessment of total parenteral nutrition admixtures by the use of fractional factorial design

    OpenAIRE

    Mirković, Dušica; Ibrić, Svetlana; Antunović, Mirjana

    2013-01-01

    Background/Aim. Parenteral nutrition as a specific aspect of providing nutritients still remains a permanent topic of both theoretical and experimental research. Total parenteral nutrition (TPN) admixtures have complex contents making difficult to maintain their stability. The most critical parameter is the diameter of a lipid droplet, i.e. droplet size distribution. It is recommended that droplet size should not be more than 5 m and that the presence of greater droplets should not exceed th...

  11. Quality assessment of total parenteral nutrition admixtures by the use of fractional factorial design

    Directory of Open Access Journals (Sweden)

    Mirković Dušica

    2013-01-01

    Full Text Available Background/Aim. Parenteral nutrition as a specific aspect of providing nutritients still remains a permanent topic of both theoretical and experimental research. Total parenteral nutrition (TPN admixtures have complex contents making difficult to maintain their stability. The most critical parameter is the diameter of a lipid droplet, i.e. droplet size distribution. It is recommended that droplet size should not be more than 5

  12. Analyzed immunogenicity of fractional doses of Sabin-inactivated poliovirus vaccine (sIPV) with intradermal delivery in rats.

    Science.gov (United States)

    Ma, Lei; Cai, Wei; Sun, Mingbo; Cun, Yina; Zhou, Jian; Liu, Jing; Hu, Wenzhu; Zhang, Xinwen; Song, Shaohui; Jiang, Shude; Liao, Guoyang

    2016-12-01

    The live-attenuated oral polio vaccine (OPV) will be no longer used when wild poliovirus (WPV) eliminating in worldwide, according to GPEI (the Global Polio Eradication Initiative) Reports. It is planning to replace OPV by Sabin-based inactivated poliovirus vaccine (sIPV) in developing countries, with purpose of reducing of the economic burden and maintaining of the appropriate antibody levels in population. It studied serial fractional doses immunized by intradermal injection (ID) in rats, to reduce consume of antigen and financial burden, maintaining sufficient immunogenicity; Methods: Study groups were divided in 4 groups of dose gradient, which were one-tenth (1/10), one-fifth (1/5), one-third (1/3) and one-full dose (1/1), according to the volume of distribution taken from the same batch of vaccine (sIPV). Wistar rats were injected intradermally with the needle and syringe sing the mantoux technique taken once month for 3 times. It was used as positive control that intramuscular inoculation (IM) was injected with one-full dose (1/1) with same batch of sIPV. PBS was used as negative control. Blood samples were collected via tail vein. After 30 d with 3 round of immunization, it analyzed the changes of neutralization antibody titers in the each group by each immunization program end; Results: The results of seroconversion had positive correlation with different doses in ID groups. The higher concentration of D-antigen (D-Ag) could conduct higher seroconversion. Furthermore, different types of viruses had different seroconversion trend. It showed that the geometric mean titers (GMTs) of each fractional-dose ID groups increased by higher concentration of D-Ag, and it got significant lower than the full-dose IM group. At 90 th days of immunization, the GMTs for each poliovirus subtypes of fractional doses were almost higher than 1:8, implied that it could be meaning positive seroprotection titer for polio vaccine types, according to WHO suggestion; Conclusions

  13. Increasing Fractional Doses Increases the Probability of Benign PSA Bounce in Patients Undergoing Definitive HDR Brachytherapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hauck, Carlin R.; Ye, Hong; Chen, Peter Y.; Gustafson, Gary S.; Limbacher, Amy; Krauss, Daniel J., E-mail: Daniel.krauss@beaumont.edu

    2017-05-01

    Purpose: Prostate-specific antigen (PSA) bounce is a temporary elevation of the PSA level above a prior nadir. The purpose of this study was to determine whether the frequency of a PSA bounce following high-dose-rate (HDR) interstitial brachytherapy for the treatment of prostate cancer is associated with individual treatment fraction size. Methods and Materials: Between 1999 and 2014, 554 patients underwent treatment of low- or intermediate-risk prostate cancer with definitive HDR brachytherapy as monotherapy and had ≥3 subsequent PSA measurements. Four different fraction sizes were used: 950 cGy × 4 fractions, 1200 cGy × 2 fractions, 1350 cGy × 2 fractions, 1900 cGy × 1 fraction. Four definitions of PSA bounce were applied: ≥0.2, ≥0.5, ≥1.0, and ≥2.0 ng/mL above the prior nadir with a subsequent return to the nadir. Results: The median follow-up period was 3.7 years. The actuarial 3-year rate of PSA bounce for the entire cohort was 41.3%, 28.4%, 17.4%, and 6.8% for nadir +0.2, +0.5, +1.0, and +2.0 ng/mL, respectively. The 3-year rate of PSA bounce >0.2 ng/mL was 42.2%, 32.1%, 41.0%, and 59.1% for the 950-, 1200-, 1350-, and 1900-cGy/fraction levels, respectively (P=.002). The hazard ratio for bounce >0.2 ng/mL for patients receiving a single fraction of 1900 cGy compared with those receiving treatment in multiple fractions was 1.786 (P=.024). For patients treated with a single 1900-cGy fraction, the 1-, 2-, and 3-year rates of PSA bounce exceeding the Phoenix biochemical failure definition (nadir +2 ng/mL) were 4.5%, 18.7%, and 18.7%, respectively, higher than the rates for all other administered dose levels (P=.025). Conclusions: The incidence of PSA bounce increases with single-fraction HDR treatment. Knowledge of posttreatment PSA kinetics may aid in decision making regarding management of potential biochemical failures.

  14. Increasing Fractional Doses Increases the Probability of Benign PSA Bounce in Patients Undergoing Definitive HDR Brachytherapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Hauck, Carlin R.; Ye, Hong; Chen, Peter Y.; Gustafson, Gary S.; Limbacher, Amy; Krauss, Daniel J.

    2017-01-01

    Purpose: Prostate-specific antigen (PSA) bounce is a temporary elevation of the PSA level above a prior nadir. The purpose of this study was to determine whether the frequency of a PSA bounce following high-dose-rate (HDR) interstitial brachytherapy for the treatment of prostate cancer is associated with individual treatment fraction size. Methods and Materials: Between 1999 and 2014, 554 patients underwent treatment of low- or intermediate-risk prostate cancer with definitive HDR brachytherapy as monotherapy and had ≥3 subsequent PSA measurements. Four different fraction sizes were used: 950 cGy × 4 fractions, 1200 cGy × 2 fractions, 1350 cGy × 2 fractions, 1900 cGy × 1 fraction. Four definitions of PSA bounce were applied: ≥0.2, ≥0.5, ≥1.0, and ≥2.0 ng/mL above the prior nadir with a subsequent return to the nadir. Results: The median follow-up period was 3.7 years. The actuarial 3-year rate of PSA bounce for the entire cohort was 41.3%, 28.4%, 17.4%, and 6.8% for nadir +0.2, +0.5, +1.0, and +2.0 ng/mL, respectively. The 3-year rate of PSA bounce >0.2 ng/mL was 42.2%, 32.1%, 41.0%, and 59.1% for the 950-, 1200-, 1350-, and 1900-cGy/fraction levels, respectively (P=.002). The hazard ratio for bounce >0.2 ng/mL for patients receiving a single fraction of 1900 cGy compared with those receiving treatment in multiple fractions was 1.786 (P=.024). For patients treated with a single 1900-cGy fraction, the 1-, 2-, and 3-year rates of PSA bounce exceeding the Phoenix biochemical failure definition (nadir +2 ng/mL) were 4.5%, 18.7%, and 18.7%, respectively, higher than the rates for all other administered dose levels (P=.025). Conclusions: The incidence of PSA bounce increases with single-fraction HDR treatment. Knowledge of posttreatment PSA kinetics may aid in decision making regarding management of potential biochemical failures.

  15. Pattern imprinting in deep sub-micron static random access memories induced by total dose irradiation

    International Nuclear Information System (INIS)

    Zheng Qi-Wen; Yu Xue-Feng; Cui Jiang-Wei; Guo Qi; Ren Di-Yuan; Cong Zhong-Chao; Zhou Hang

    2014-01-01

    Pattern imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is investigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell's static noise margin (SNM) and the background data, and study the influence of irradiation on the probability density function of ΔSNM, which is the difference between two data sides' SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation (STI) oxide rather than from the gate oxide of the micron-device. (condensed matter: structural, mechanical, and thermal properties)

  16. Total-dose radiation effects data for semiconductor devices. 1985 supplement. Volume 2, part A

    International Nuclear Information System (INIS)

    Martin, K.E.; Gauthier, M.K.; Coss, J.R.; Dantas, A.R.V.; Price, W.E.

    1986-05-01

    Steady-state, total-dose radiation test data, are provided in graphic format for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. This volume provides data on integrated circuits. The data are presented in graphic, tabular, and/or narrative format, depending on the complexity of the integrated circuit. Most tests were done using the JPL or Boeing electron accelerator (Dynamitron) which provides a steady-state 2.5 MeV electron beam. However, some radiation exposures were made with a cobalt-60 gamma ray source, the results of which should be regarded as only an approximate measure of the radiation damage that would be incurred by an equivalent electron dose

  17. Pattern imprinting in deep sub-micron static random access memories induced by total dose irradiation

    Science.gov (United States)

    Zheng, Qi-Wen; Yu, Xue-Feng; Cui, Jiang-Wei; Guo, Qi; Ren, Di-Yuan; Cong, Zhong-Chao; Zhou, Hang

    2014-10-01

    Pattern imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is investigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell's static noise margin (SNM) and the background data, and study the influence of irradiation on the probability density function of ΔSNM, which is the difference between two data sides' SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation (STI) oxide rather than from the gate oxide of the micron-device.

  18. Results of Hematopoietic Stem Cell Transplantation After Treatment With Different High-Dose Total-Body Irradiation Regimens in Five Dutch Centers

    International Nuclear Information System (INIS)

    Loes van Kempen-Harteveld, M.; Brand, Ronald; Kal, Henk B.; Verdonck, Leo F.; Hofman, Pieter; Schattenberg, Anton V.; Maazen, Richard W. van der; Cornelissen, Jan J.; Eijkenboom, Wil M.H.; Lelie, Johannes P. van der; Oldenburger, Foppe; Barge, Renee M.; Biezen, Anja van; Vossen, Jaak M.J.J.; Noordijk, Evert M.; Struikmans, Henk

    2008-01-01

    Purpose: To evaluate results of high-dose total-body irradiation (TBI) regimens for hematopoietic stem cell transplantation. Methods and Materials: A total of 1,032 patients underwent TBI in one or two fractions before autologous or allogeneic hematologic stem cell transplantation for acute leukemia and non-Hodgkin's lymphoma. The TBI regimens were normalized by using the biological effective dose (BED) concept. The BED values were divided into three dose groups. Study end points were relapse incidence (RI), non-relapse mortality (NRM), relapse-free survival (RFS), and overall survival (OS). Multivariate analysis was performed, stratified by disease. Results: In the highest TBI dose group, RI was significantly lower and NRM was higher vs. the lower dose groups. However, a significant influence on RFS and OS was not found. Relapses in the eye region were found only after shielding to very low doses. Age was of significant influence on OS, RFS, and NRM in favor of younger patients. The NRM of patients older than 40 years significantly increased, and OS decreased. There was no influence of age on RI. Men had better OS and RFS and lower NRM. Type of transplantation significantly influenced RI and NRM for patients with acute leukemia and non-Hodgkin's lymphoma. There was no influence on RFS and OS. Conclusions: Both RI and NRM were significantly influenced by the size of the BED of single-dose or two-fraction TBI regimens; OS and RFS were not. Age was of highly significant influence on NRM, but there was no influence of age on RI. Hyperfractionated TBI with a high BED might be useful, assuming NRM can be reduced

  19. Differences in Clinical Results After LINAC-Based Single-Dose Radiosurgery Versus Fractionated Stereotactic Radiotherapy for Patients With Vestibular Schwannomas

    International Nuclear Information System (INIS)

    Combs, Stephanie E.; Welzel, Thomas; Schulz-Ertner, Daniela; Huber, Peter E.; Debus, Juergen

    2010-01-01

    Purpose: To evaluate the outcomes of patients with vestibular schwannoma (VS) treated with fractionated stereotactic radiotherapy (FSRT) vs. those treated with stereotactic radiosurgery (SRS). Methods and Materials: This study is based on an analysis of 200 patients with 202 VSs treated with FSRT (n = 172) or SRS (n = 30). Patients with tumor progression and/or progression of clinical symptoms were selected for treatment. In 165 out of 202 VSs (82%), RT was performed as the primary treatment for VS, and for 37 VSs (18%), RT was conducted for tumor progression after neurosurgical intervention. For patients receiving FSRT, a median total dose of 57.6 Gy was prescribed, with a median fractionation of 5 x 1.8 Gy per week. For patients who underwent SRS, a median single dose of 13 Gy was prescribed to the 80% isodose. Results: FSRT and SRS were well tolerated. Median follow-up time was 75 months. Local control was not statistically different for both groups. The probability of maintaining the pretreatment hearing level after SRS with doses of ≤13 Gy was comparable to that of FSRT. The radiation dose for the SRS group (≤13 Gy vs. >13 Gy) significantly influenced hearing preservation rates (p = 0.03). In the group of patients treated with SRS doses of ≤13 Gy, cranial nerve toxicity was comparable to that of the FSRT group. Conclusions: FSRT and SRS are both safe and effective alternatives for the treatment of VS. Local control rates are comparable in both groups. SRS with doses of ≤13 Gy is a safe alternative to FSRT. While FSRT can be applied safely for the treatment of VSs of all sizes, SRS should be reserved for smaller lesions.

  20. Insect radiosensitivity: dose curves and dose-fractionation studies of dominant lethal mutations in the mature sperm of 4 insect species

    International Nuclear Information System (INIS)

    LaChance, L.E.; Graham, C.K.

    1984-01-01

    Males of 4 species of insects: Musca domestica L. (housefly) (Diptera), Oncopeltus fasciatus (Dallas) (milkweed bug) (Hemiptera), Anagasta kuhniella (Zeller) (mealmoth) (Lepidoptera) and Heliothis virescens (Fab.) (tobacco budworm) (Lepidoptera) were irradiated as adults. Dose-response curves for the induction of dominant lethal mutations in the mature sperm were constructed. The curves were analyzed mathematically and compared with theoretical computer simulated curves requiring 1, 2, 4, 8 and 16 'hits' for the induction of a dominant lethal mutation. The 4 species belonging to 3 different orders of insects showed a wide range in radiation sensitivity and vastly different dose-response curves. When the data were analyzed by several mathematical models the authors found that a logistic response curve gave reasonably good fit with vastly different parameters for the 4 species. Dose-fractionation experiments showed no reduction in the frequency of lethal mutations induced in any species when an acute dose was fractionated into 2 equal exposures separated by an 8-h period. (Auth.)

  1. The review of radiation effects of γ total dose in CMOS circuits

    International Nuclear Information System (INIS)

    Chen Panxun; Gao Wenming; Xie Zeyuan; Mi Bang

    1992-01-01

    Radiation performances of commercial and rad-hard CMOS circuits are reviewed. Threshold voltage, static power current, V in -V out characteristic and propagation delay time related with total dose are presented for CMOS circuits from several manufacturing processes. The performance of radiation-annealing of experimental circuits had been observed for two years. The comparison has been made between the CMOS circuits made in China and the commercial RCA products. 60 Co γ source can serve as γ simulator of the nuclear explosion

  2. Unscheduled DNA synthesis in spleen cells of mice exposed to low doses of total body irradiation

    International Nuclear Information System (INIS)

    Tuschl, H.; Kovac, R.; Hruby, E.

    1983-07-01

    Unscheduled DNA synthesis was induced by UV irradiation of spleen cells obtained from C 57 Bl mice after repeated total body irradiation of 0.05 Gy 60 Co (0.00125 Gy/mice) and determined autoradiographically. An enhancement in the ability for repair of UV induced DNA lesions was observed in cells of gamma irradiated animals. While the amount of 3 H-thymidine incorporated per cell was increased, the percentage of labeled cells remained unchanged. The present results are compared with previous data on low dose radiation exposure in men. (Author) [de

  3. The impact of radiation dose and fractionation on the risk factor of radiation pneumonitis on four radiation therapy oncology group (RTOG) lung cancer trials

    International Nuclear Information System (INIS)

    Roach, Mack; Pajak, Thomas F; Byhardt, Roger; Graham, Mary L; Asbell, Sucha O; Russell, Anthony H; Fu, Karen K; Urtasun, Raul C; Herskovic, Arnold M; Cox, James D

    1997-01-01

    Purpose/Objective: To assess the relationship between total dose of radiation delivered, the fractionation scheme used, age, and Karnofsky Performance Status (KPS) on the risk of moderate to severe (≥ Grade 2) radiation pneumonitis in patients treated with radiotherapy alone for lung cancer on four RTOG Trials. Materials and Methods: Between February of 1984 and April of 1989, 1701 patients with clinically localized (I-IIIb) lung cancer were entered on clinical trials employing radiotherapy alone. Twelve hundred and forty-seven patients were entered on RTOG 8311 or 8407 (phase I/II trials) and 454 patients were entered on RTOG 8321 or 8403 (phase III trials). RTOG 8403 and 8321 patients received once-a-day irradiation to 60 Gy. Patients treated on RTOG 8407 were treated with a concomitant boost technique in a non-randomized fashion to 64.8, 69.6, 74.4 or 79.2 Gy. Patients treated on RTOG 8407 were treated with a concomitant boost technique in a non-randomized fashion to 63 Gy or 70.2 Gy. All patients were assessed for the incidence of Grade 2-5, radiation pneumonitis. One hundred and seven (6%) of patients were either ineligible or canceled (n=60), or were excluded because of incomplete data (n=47). The factors evaluated included total dose of radiation, the fractionation scheme, age and pre-treatment KPS. Patients treated to doses ≥ 72 Gy were considered to have received high doses (72.0 - 81.6 Gy), while the remaining patients treated to doses < 72 Gy (57.6 - 71.9 Gy) were considered to have received standard dose radiation. For the this analysis, information regarding field size and baseline pulmonary function was not available. Results: Age, sex, stage distribution, and the percentage of patients with a KPS ≥90 were similar among the patients treated on these four studies. Patients receiving hyperfractionated radiotherapy to doses ≥ 72 Gy experienced a higher incidence of radiation pneumonitis ≥ Grade 2, than patients treated with standard doses < 72

  4. The biological effects of high dose total body irradiation in beagle dogs

    International Nuclear Information System (INIS)

    Luo Qingliang; Liu Xiaolan; Hao Jing; Xiong Guolin; Dong Bo; Zhao Zhenhu; Xia Zhengbiao; Qiu Liling; Mao Bingzhi

    2002-01-01

    Objective: To evaluate the biological effects of Beagle dogs irradiated by γ-rays at different doses. Methods: All Beagle dogs were divided into six groups and were subjected respectively to total-body irradiation (TBI) with a single dose of 6.5, 5.5, 5.0, 4.5, 3, 5 and 2.5 Gy γ-rays delivered by 60 Co sources at 7.224 x 10 -2 C/kg per minute. The general condition, blood cell counts and bone marrow cell CFC assays were observed. Results: Vomiting occurred at 0.5 to 2 hours after TBI in all groups. In 6.5 Gy group 3/5 dogs had blood-watery stool and 1/5 in 5.5 Gy group had watery stool. Diarrhea occurred in all other animals. Only one dog in 2.5 Gy group survived, all of others died. in order of decreasing irradiation dosage, the average survival time was 5.0, 8.0, 9.3, 9.5, 10.5 and 14.1 days, respectively. Conclusions: According to the clinical symptoms, leukocyte count and survival time of the dogs, the irradiation dose which will induce very severe hematopoietic radiation syndrome in Beagle dogs is 4.5 to 5.0 Gy

  5. The effect of low-dose total body irradiation on tumor control

    International Nuclear Information System (INIS)

    Sakamoto, Kiyohiko; Miyamoto, Miyako; Watabe, Nobuyuki.

    1987-01-01

    Total body irradiation (TBI) is considered to bring about an immunosuppressive effect on an organism, on the basis of data obtained from sublethal doses of TBI. However, there are no data on how low-dose TBI affects an organism. Over the last five years, we have been studying the effects of low-dose TBI on normal or tumor-bearing mice and the immunological background of these effects. In experimental studies, an increase in the TD50 value (the number of cells required for a tumor incidence of 50 %) in mice exposed to 10 rad was recognized and showed a remarkable increase at 6 hours to 15 hours after irradiation. TBI of 10 rad also showed an enhancement effect on tumor cell killing when given 12 hours before local tumor irradiation. In order to clarify the mechanism of this kind of effect, some immunological studies were performed using several immunological procedures, and the results suggested that 10 rad of TBI caused increasing tumor immunity in irradiated mice. Clinical trials in some patients with advanced tumors are now being undertaken on the basis of these experimental data, and the effect of TBI on tumor control appears promising, although it is too early to draw conclusions. (author)

  6. Biologically effective dose in total-body irradiation and hematopoietic stem cell transplantation

    International Nuclear Information System (INIS)

    Kal, H.B.; Kempen-Harteveld, M.L. van; Heijenbrok-Kal, M.H.; Struikmans, H.

    2006-01-01

    Background and Purpose: Total-body irradiation (TBI) is an important part of the conditioning regimen for hematopoietic stem cell transplantation (HSCT) in patients with hematologic malignancies. The results after treatment with various TBI regimes were compared, and dose-effect relationships for the endpoints relapse incidence, disease-free survival, treatment-related mortality, and overall survival were derived. The aim was to define requirements for an optimal treatment schedule with respect to leukemic cell kill and late normal-tissue morbidity. Material and Methods: A literature search was performed. Three randomized studies, four studies comparing results of two or three TBI regimens, and nine reports with results of one specific TBI regimen were identified. Biologically effective doses (BEDs) were calculated. The results of the randomized studies and the studies comparing results of two or three TBI regimens were pooled, and the pooled relative risk (RR) was calculated for the treatments with high BED values versus treatments with a low BED. BED-effect relationships were obtained. Results: RRs for the high BED treatments were significantly lower for relapse incidence, not significantly different for disease-free survival and treatment-related mortality, and significantly higher for overall survival. BED-effect relationships indicate a decrease in relapse incidence and treatment-related mortality and an increase in disease-free and overall survival with higher BED values. Conclusion: 'More dose is better', provided that a TBI setting is used limiting the BEDs of lungs, kidneys, and eye lenses. (orig.)

  7. In pediatric leukemia, dose evaluation according to the type of compensators in total body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Yeon [Dongnam Inst. of Radiological and Medical science, Busan (Korea, Republic of); Kim, Chang Soo; Kim, Jung Hoon [Dept. of Radiological Science, College of Health Science, Catholic University of Busan, Busan (Korea, Republic of)

    2015-04-15

    Total body irradiation (TBI) and chemotherapy are the pre-treatment method of a stem cell transplantations of the childhood leukemia. in this study, we evaluate the Quantitative human body dose prior to the treatment. The MCNPX simulation program evaluated by changing the material of the tissue compensators with imitation material of pediatric exposure in a virtual space. As a result, first, the average skin dose with the material of the tissue compensators of Plexiglass tissue compensators is 74.60 mGy/min, Al is 73.96 mGy/min, Cu is 72.26 mGy/min and Pb 67.90 mGy/min respectively. Second, regardless of the tissue compensators material that organ dose were thyroid, gentile, digestive system, brain, lungs, kidneys higher in order. Finally, the ideal distance between body compensator and the patient were 50 cm aparting each other. In conclusion, tissue compensators Al, Cu, Pb are able to replace of the currently used in Plexiglass materials.

  8. Optimization of the temporal pattern of applied dose for a single fraction of radiation: Implications for radiation therapy

    Science.gov (United States)

    Altman, Michael B.

    The increasing prevalence of intensity modulated radiation therapy (IMRT) as a treatment modality has led to a renewed interest in the potential for interaction between prolonged treatment time, as frequently associated with IMRT, and the underlying radiobiology of the irradiated tissue. A particularly relevant aspect of radiobiology is cell repair capacity, which influences cell survival, and thus directly relates to the ability to control tumors and spare normal tissues. For a single fraction of radiation, the linear quadratic (LQ) model is commonly used to relate the radiation dose to the fraction of cells surviving. The LQ model implies a dependence on two time-related factors which correlate to radiobiological effects: the duration of radiation application, and the functional form of how the dose is applied over that time (the "temporal pattern of applied dose"). Although the former has been well studied, the latter has not. Thus, the goal of this research is to investigate the impact of the temporal pattern of applied dose on the survival of human cells and to explore how the manipulation of this temporal dose pattern may be incorporated into an IMRT-based radiation therapy treatment planning scheme. The hypothesis is that the temporal pattern of applied dose in a single fraction of radiation can be optimized to maximize or minimize cell kill. Furthermore, techniques which utilize this effect could have clinical ramifications. In situations where increased cell kill is desirable, such as tumor control, or limiting the degree of cell kill is important, such as the sparing of normal tissue, temporal sequences of dose which maximize or minimize cell kill (temporally "optimized" sequences) may provide greater benefit than current clinically used radiation patterns. In the first part of this work, an LQ-based modeling analysis of effects of the temporal pattern of dose on cell kill is performed. Through this, patterns are identified for maximizing cell kill for a

  9. Fractional rate of degradation (kd) of starch in the rumen and its relation to in vivo rumen and total digestibility

    DEFF Research Database (Denmark)

    Hvelplund, Torben; Larsen, Mogens; Lund, Peter

    2009-01-01

    in different ways both chemically and physically. The starch sources were fed in mixed diets together with grass silage and soya bean meal and allocated ad libitum to fistulated dairy cows. The starch content varied between 13 and 35% in ration dry matter for the different starch sources. The design...... was a series of cross-over experiments with two cows and two periods. Ruminal starch pool was estimated from rumen evacuation and starch flow was estimated by duodenal and faeces sampling. Fractional rate of rumen degradation was estimated from the equation [kd = rumen degraded/rumen pool] and rumen and total...

  10. A unified dose response relationship to predict high dose fractionation response in the lung cancer stereotactic body radiation therapy

    Directory of Open Access Journals (Sweden)

    Than S Kehwar

    2017-01-01

    Full Text Available Aim: This study is designed to investigate the superiority and applicability of the model among the linear-quadratic (LQ, linear-quadratic-linear (LQ-L and universal-survival-curve (USC models by fitting published radiation cell survival data of lung cancer cell lines. Materials and Method: The radiation cell survival data for small cell (SC and non-small cell (NSC lung cancer cell lines were obtained from published reports, and were used to determine the LQ and cell survival curve parameters, which ultimately were used in the curve fitting of the LQ, LQ-L and USC models. Results: The results of this study demonstrate that the LQ-L(Dt-mt model, compared with the LQ and USC models, provides best fit with smooth and gradual transition to the linear portion of the curve at transition dose Dt-mt, where the LQ model loses its validity, and the LQ-L(Dt-2α/β and USC(Dt-mt models do not transition smoothly to the linear portion of the survival curve. Conclusion: The LQ-L(Dt-mt model is able to fit wide variety of cell survival data over a very wide dose range, and retains the strength of the LQ model in the low-dose range.

  11. A first-principles approach to total-dose hardness assurance

    International Nuclear Information System (INIS)

    Fleetwood, D.M.

    1995-01-01

    A first-principles approach to radiation hardness assurance was described that provides the technical background to the present US and European total-dose radiation hardness assurance test methods for MOS technologies, TM 1019.4 and BS 22900. These test methods could not have been developed otherwise, as their existence depends not on a wealth of empirical comparisons of IC data from ground and space testing, but on a fundamental understanding of MOS defect growth and annealing processes. Rebound testing should become less of a problem for advanced MOS small-signal electronics technologies for systems with total dose requirements below 50--100 krad(SiO 2 ) because of trends toward much thinner gate oxides. For older technologies with thicker gate oxides and for power devices, rebound testing is unavoidable without detailed characterization studies to assess the impact of interface traps on devices response in space. The QML approach is promising for future hardened technologies. A sufficient understanding of process effects on radiation hardness has been developed that should be able to reduce testing costs in the future for hardened parts. Finally, it is hoped that the above discussions have demonstrated that the foundation for cost-effective hardness assurance tests is laid with studies of the basic mechanisms of radiation effects. Without a diligent assessment of new radiation effects mechanisms in future technologies, one cannot be assured that the present generation of radiation test standards will continue to apply

  12. A rapid infusion protocol is safe for total dose iron polymaltose: time for change.

    Science.gov (United States)

    Garg, M; Morrison, G; Friedman, A; Lau, A; Lau, D; Gibson, P R

    2011-07-01

    Intravenous correction of iron deficiency by total dose iron polymaltose is inexpensive and safe, but current protocols entail prolonged administration over more than 4 h. This results in reduced patient acceptance, and hospital resource strain. We aimed to assess prospectively the safety of a rapid intravenous protocol and compare this with historical controls. Consecutive patients in whom intravenous iron replacement was indicated were invited to have up to 1.5 g iron polymaltose by a 58-min infusion protocol after an initial 15-min test dose without pre-medication. Infusion-related adverse events (AE) and delayed AE over the ensuing 5 days were also prospectively documented and graded as mild, moderate or severe. One hundred patients, 63 female, mean age 54 (range 18-85) years were studied. Thirty-four infusion-related AE to iron polymaltose occurred in a total of 24 patients--25 mild, 8 moderate and 1 severe; higher than previously reported for a slow protocol iron infusion. Thirty-one delayed AE occurred in 26 patients--26 mild, 3 moderate and 2 severe; similar to previously reported. All but five patients reported they would prefer iron replacement through the rapid protocol again. The presence of inflammatory bowel disease (IBD) predicted infusion-related reactions (54% vs 14% without IBD, P cost, resource utilization and time benefits for the patient and hospital system. © 2011 The Authors. Internal Medicine Journal © 2011 Royal Australasian College of Physicians.

  13. Influence of burn-in on total-ionizing-dose effect of SRAM device

    International Nuclear Information System (INIS)

    Liu Minbo; Yao Zhibin; Huang Shaoyan; He Baoping; Sheng Jiangkun

    2014-01-01

    The influence of Burn-in on the total-ionizing-dose (TID) effect of SRAM device was investigated. SRAM devices of three different feature sizes were selected and irradiated by "6"0Co source with or without pre-irradiation Burn-in. Some parameters for radiation effect of SRAM device such as upset data, were measured, and the influence on the TID effect of different feature size SRAM devices with or without pre-irradiation Burn-in was obtained. The influence of different temperature Burn-in on radiation resistant capability of SRAM device was studied for 0.25 μm SRAM device. The results show that the smaller the device feature size is, the better the radiation-resistant capability of SRAM device is and the weaker the influence of Burn-in is. And the higher Burn-in temperature is, the more serious the influence of Burn-in on the total-dose radiation effect is. (authors)

  14. SU-E-J-176: Characterization of Inter-Fraction Breast Variability and the Implications On Delivered Dose

    Energy Technology Data Exchange (ETDEWEB)

    Sudhoff, M; Lamba, M; Kumar, N; Ward, A; Elson, H [University of Cincinnati, Cincinnati, OH (United States)

    2015-06-15

    Purpose: To systematically characterize inter-fraction breast variability and determine implications on delivered dose. Methods: Weekly port films were used to characterize breast setup variability. Five evenly spaced representative positions across the contour of each breast were chosen on the electronic port film in reference to graticule, and window and level was set such that the skin surface of the breast was visible. Measurements from the skin surface to treatment field edge were taken on each port film at each position and compared to the planning DRR, quantifying the variability. The systematic measurement technique was repeated for all port films for 20 recently treated breast cancer patients. Measured setup variability for each patient was modeled as a normal distribution. The distribution was randomly sampled from the model and applied as isocentric shifts in the treatment planning computer, representing setup variability for each fraction. Dose was calculated for each shifted fraction and summed to obtain DVHs and BEDs that modeled the dose with daily setup variability. Patients were categorized in to relevant groupings that were chosen to investigate the rigorousness of immobilization types, treatment techniques, and inherent anatomical difficulties. Mean position differences and dosimetric differences were evaluated between planned and delivered doses. Results: The setup variability was found to follow a normal distribution with mean position differences between the DRR and port film between − 8.6–3.5 mm with sigma range of 5.3–9.8 mm. Setup position was not found to be significantly different than zero. The mean seroma or whole breast PTV dosimetric difference, calculated as BED, ranged from a −0.23 to +1.13Gy. Conclusion: A systematic technique to quantify and model setup variability was used to calculate the dose in 20 breast cancer patients including variable setup. No statistically significant PTV or OAR BED differences were found between

  15. Total Ambient Dose Equivalent Buildup Factor Determination for Nbs04 Concrete.

    Science.gov (United States)

    Duckic, Paulina; Hayes, Robert B

    2018-06-01

    Buildup factors are dimensionless multiplicative factors required by the point kernel method to account for scattered radiation through a shielding material. The accuracy of the point kernel method is strongly affected by the correspondence of analyzed parameters to experimental configurations, which is attempted to be simplified here. The point kernel method has not been found to have widespread practical use for neutron shielding calculations due to the complex neutron transport behavior through shielding materials (i.e. the variety of interaction mechanisms that neutrons may undergo while traversing the shield) as well as non-linear neutron total cross section energy dependence. In this work, total ambient dose buildup factors for NBS04 concrete are calculated in terms of neutron and secondary gamma ray transmission factors. The neutron and secondary gamma ray transmission factors are calculated using MCNP6™ code with updated cross sections. Both transmission factors and buildup factors are given in a tabulated form. Practical use of neutron transmission and buildup factors warrants rigorously calculated results with all associated uncertainties. In this work, sensitivity analysis of neutron transmission factors and total buildup factors with varying water content has been conducted. The analysis showed significant impact of varying water content in concrete on both neutron transmission factors and total buildup factors. Finally, support vector regression, a machine learning technique, has been engaged to make a model based on the calculated data for calculation of the buildup factors. The developed model can predict most of the data with 20% relative error.

  16. Low-dose fractionated radiotherapy and concomitant chemotherapy for recurrent or progressive glioblastoma. Final report of a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Balducci, M.; Diletto, B.; Chiesa, S.; D' Agostino, G.R.; Gambacorta, M.A.; Ferro, M.; Valentini, V. [Catholic University of the Sacred Heart, Department of Radiation Oncology, Rome (Italy); Colosimo, C. [Catholic University of the Sacred Heart, Department of Radiology, Rome (Italy); Maira, G.; Anile, C. [Catholic University of the Sacred Heart, Department of Neurosurgery, Rome (Italy)

    2014-04-15

    Evaluated in this study were the feasibility and the efficacy of concurrent low dose fractionated radiotherapy (LD-FRT) and chemotherapy as palliative treatment for recurrent/progressive glioblastoma multiforme (GBM). Eligible patients had recurrent or progressive GBM, Karnofsky performance status ≥70, prior surgery, and standard radiochemotherapy treatment. Recurrence/progression disease during temozolomide (TMZ) received cisplatin (CDDP; 30 mg/m{sup 2} on days 1, 8, 15), fotemustine (FTM; 40 mg/m{sup 2} on days 2, 9, 16), and concurrent LD-FRT (0.3 Gy twice daily); recurrence/progression after 4 months from the end of adjuvant TMZ were treated by TMZ (150/200 mg/m{sup 2} on days 1-5) concomitant with LD-FRT (0.4 Gy twice daily). Primary endpoints were safety and toxicity. A total of 32 patients were enrolled. Hematologic toxicity G1-2 was observed in 18.7% of patients and G3-4 in 9.4%. One patient (3.1%) had complete response, 3 (9.4%) had partial response, 8 (25%) had stable disease for at least 8 weeks, while 20 patients (62.5%) experienced progressive disease. The clinical benefit was 37.5%. Median progression-free survival (PFS) and overall survival (OS) were 5 and 8 months, respectively. Survival rate at 12 months was of 27.8%. LD-FRT and chemotherapy for recurrent/progressive GBM have a good toxicity profile and clinical outcomes, even though further investigation of this novel palliative treatment approach is warranted. (orig.)

  17. A reviewed technique for total body electron therapy using a Varian Clinac 2100C/D high dose rate treatment beam facility

    International Nuclear Information System (INIS)

    Oliver, L.D.; Xuereb, E.M.A.; Last, V.; Hunt, P.B.; Wilfert, A.

    1996-01-01

    Our (Royal North Shore Hospital) most recent linear accelerator acquisition is a Varian Clinac 2100C/D which has a high dose rate (approximately 25Gy per minute at 1 metre) total body electron option. We investigated the physical characteristics of the electron beam to develop a suitable method of treatment for total body electron therapy. The useful electron beam width is defined as 80cm above and below the reference height. Measurements of the electron dose received from the two angled electron beams showed a critical dependence on the gantry angles. The treatment protocol uses ten different patient angles, fractionated into directly opposing fields and treated seuqentially each day. A full cycle of treatment is completed in five days. (author)

  18. Low-dose X-irradiation of adjuvant-induced arthritis in rats. Efficacy of different fractionation schedules

    International Nuclear Information System (INIS)

    Liebmann, A.; Hindemith, M.; Jahns, J.; Kamprad, F.; Hildebrandt, G.; Madaj-Sterba, P.; Weisheit, S.

    2004-01-01

    Background and purpose: low-dose radiotherapy is widely accepted as a very effective treatment option for inflammatory symptoms associated with painful degenerative joint disorders. Radiation doses and fractionation schedules in practical use are empirical and mainly based on clinical observations. Experimental data are rare. The efficacy of low-dose X-irradiation on adjuvant induced arthritis in rats using different fractionation schemes was investigated in vivo, in order to explore whether there is a dose and fractionation dependence. Material and methods: adjuvant arthritis in female lewis rats (n = 128) was induced by intradermal injection of heat-inactivated Mycobacterium tuberculosis on day 0. Both arthritic hind paws were sham-irradiated (group 1: days 10-14; group 2: days 15-19; group 3: days 22-26) or X-irradiated with either 5 x 1.0 Gy (group 4: days 10-14; group 6: days 15-19; group 8: days 22-26; group 10: days 10, 12, 14, 16, and 18) or 5 x 0.5 Gy (group 5: days 10-14; group 7: days 15-19; group 9: days 22-26; group 11: days 10, 12, 14, 16, and 18; group 12: days 10-14 and 22-26). The clinical parameters arthritis score (AS), hind paw volume (HPV), and body weight were determined. Results: a significant decrease of the clinical arthritis parameters was observed following 5 x 0.5 Gy or 5 x 1.0 Gy during the acute maximum of the inflammatory response (days 15-19). The most pronounced treatment effect was reached after two daily fractionated series of 5 x 0.5 Gy with an early treatment onset (days 10-14) and repetition in interval (days 22-26). After the application of 5 x 1.0 Gy on days 10-14 or in a protracted scheme (days 10, 12, 14, 16, and 18), only a nonsignificant positive trend could be detected. Daily fractionated X-irradiation in the chronic phase of adjuvant arthritis (days 22-26) did not show any positive clinical effect. Conclusion: low-dose radiotherapy is able to prevent a full-blown arthritic reaction if given during the florid phase of

  19. Radiosensitivity of Nicotiana protoplasts. Action on cell; cycle effects of low dose and fractionated irradiations; biological repair

    International Nuclear Information System (INIS)

    Magnien, E.

    1981-10-01

    Leaf protoplasts of Nicotiana plumbaginifolia and Nicotiana sylvestris demonstrate five main qualities: they can be maintained as haploid lines; they constitute starting populations with a remarkable cytological homogeneity; they show a transient initial lag-phase; they yield very high plating efficiencies and retain permanently a complete differentiation capacity; being derived of a cell wall, they appear well adapted for fusion experiments or enzymatic dosages. The resumption of mitotic activity was followed by cytophotometric measurements, labelling experiments, nuclear sizing and enzymatic assays. The action of 5 Gy gamma-ray irradiations delayed entrance in the S-phase, provoked an otherwise not verified dependency between transcription, translation and protein synthesis, increased nuclear volumes in the G2-phase, and slightly stimulated the activity of a repair enzyme. The plating efficiency was a sensitive end-point which allowed the evaluation of the biological effectiveness of low to medium radiation-doses after gamma-ray and fast neutron irradiations. The neutron dose-RBE relationship increased from 3 to 25 when the dose decreased from 5 Gy to 5 mGy. When fractionated into low single doses only, a neutron dose of 300 mGy markedly increased its biological effectiveness: this phenomenon could not be explained by cell progression, and necessitated additional hypotheses involving other mechanisms in the specific action of low radiation doses. Radiation-induced UDS was measured in presence of aphidicolin. A beta-like DNA-polymerase was shown to be definitely involved in nuclear repair synthesis [fr

  20. Stage, tumor growth rate and optimal dose fractionation schedules in the treatment of squamous cell carcinoma of the head and neck

    International Nuclear Information System (INIS)

    Sugawara, Tadashi; Morita, Mamoru; Aihara, Toshinori; Tanaka, Osamu

    1983-01-01

    In 77 patients with cancer of the head and neck, 45 patients received radiotherapy alone, while 32 patients with T 1 or T 2 glottic cancer received combined therapy with laryngomicrosurgery performed prior to or during the course of irradiation. These T 1 and T 2 groups were separately analyzed from other T 1 and T 2 groups as T sub(LMS). Local recurrence rates were compared concerning overall time and fraction size in following three subgroups, i.e., T sub(LMS), Tsub(1+2), and Tsub(3+4). No significant correlation was detected between total dose converted to partial tolerance (PT) and local control in all subgroups except for Tsub(3+4), in which local recurrence rate was rather higher in high PT range. Local control was significantly dependent on overall treatment time and fraction size, differently by tumor stage. Favorable fractionation schedules considered as optimal for T sub(LMS) were those in which treatment was given 5 times weekly with a daily dose rate more than 196 rad in a shorter overall time of less than 42 days. In contrast to T sub(LMS), effective schedules for Tsub(3+4) consisted of longer overall time of more than 60 days and a lower daily dose rate of less than 153 rad. In Tsub(1+2), the optimal schedule was needed to be altered according to rapidness of progression of disease characterised by duration of the complaints, which was statistically proved to be significantly shorter in Tsub(1+2) than Tsub(3+4). Rapidity-adjusted schedule consisted of a shorter over-all time of less than 49 days with a daily dose rate of more than 175 rad 5 fractions a week for a case having a duration of complaints of less than 2.9 months, and a longer overall time of more than 50 days with a daily dose rate of less than 174 rad for a case having a duration of more than 3 months. (J.P.N.)

  1. In vivo assessment of catheter positioning accuracy and prolonged irradiation time on liver tolerance dose after single-fraction 192Ir high-dose-rate brachytherapy

    Directory of Open Access Journals (Sweden)

    Kropf Siegfried

    2011-09-01

    Full Text Available Abstract Background To assess brachytherapy catheter positioning accuracy and to evaluate the effects of prolonged irradiation time on the tolerance dose of normal liver parenchyma following single-fraction irradiation with 192 Ir. Materials and methods Fifty patients with 76 malignant liver tumors treated by computed tomography (CT-guided high-dose-rate brachytherapy (HDR-BT were included in the study. The prescribed radiation dose was delivered by 1 - 11 catheters with exposure times in the range of 844 - 4432 seconds. Magnetic resonance imaging (MRI datasets for assessing irradiation effects on normal liver tissue, edema, and hepatocyte dysfunction, obtained 6 and 12 weeks after HDR-BT, were merged with 3D dosimetry data. The isodose of the treatment plan covering the same volume as the irradiation effect was taken as a surrogate for the liver tissue tolerance dose. Catheter positioning accuracy was assessed by calculating the shift between the 3D center coordinates of the irradiation effect volume and the tolerance dose volume for 38 irradiation effects in 30 patients induced by catheters implanted in nearly parallel arrangement. Effects of prolonged irradiation were assessed in areas where the irradiation effect volume and tolerance dose volume did not overlap (mismatch areas by using a catheter contribution index. This index was calculated for 48 irradiation effects induced by at least two catheters in 44 patients. Results Positioning accuracy of the brachytherapy catheters was 5-6 mm. The orthogonal and axial shifts between the center coordinates of the irradiation effect volume and the tolerance dose volume in relation to the direction vector of catheter implantation were highly correlated and in first approximation identically in the T1-w and T2-w MRI sequences (p = 0.003 and p p = 0.001 and p = 0.004, respectively. There was a significant shift of the irradiation effect towards the catheter entry site compared with the planned dose

  2. Effect of dose fractionation of 60Co gamma radiation on longevity and reproduction of Sitophilus granarius (L., 1785) (Col., Curculionidae) in wheat

    International Nuclear Information System (INIS)

    Arthur, V.; Walder, J.M.M.; Wiendl, F.M.; Domarco, R.E.; Haddad, S.S.

    1987-01-01

    The effects of fractionated doses of gamma radiation in different interval of time on longevity and reproductivity of Sitophilus granarius (L., 1785) are studied. Gamma radiation was provided at dose rate of 1.56 kGy/hour by a Cobalt 60 source (Gammabeam-650). The insects were divided in two sets: one was irradiated at acute doses and the other in fractionated doses, with interval of 48 hours. Both sets received doses of 0,40, 50, 60, 70, 80, 90 and 100Gy. Mortality and and emergency were determined weekly. (M.A.C.) [pt

  3. Northern Marshall Islands radiological survey: terrestrial food chain and total doses

    International Nuclear Information System (INIS)

    Robison, W.L.; Mount, M.E.; Phillips, W.A.; Conrado, C.A.; Stuart, M.L.; Stoker, C.E.

    1982-01-01

    A radiological survey was conducted from September through November of 1978 to assess the concentrations of persistent manmade radionuclides in the terrestrial and marine environments of 11 atolls and 2 islands in the Northern Marshall Islands. The survey consisted mainly of an aerial radiological reconnaissance to map the external gamma-ray exposure rates over the islands of each atoll. The logistical support for the entire survey was designed to accommodate this operation. As a secondary phase of the survey, shore parties collected appropriate terrestrial and marine samples to assess the radiological dose from pertinent food chains to those individuals residing on the atolls, who may in the future reside on some of the presently uninhabited atolls, or who collect food from these atolls. Over 5000 terrestrial and marine samples were collected for radionuclide analysis from 76 different islands. Soils, vegetation, indigenous animals, and cistern water and groundwater were collected from the islands. Reef and pelagic fish, clams, lagoon water, and sediments were obtained from the lagoons. The concentration data for 90 Sr, 137 Cs, 238 Pu, 239 240 Pu, and 241 Am in terrestrial food crops, fowl, and animals collected at the atolls or islands are summarized. An assessment of the total dose from the major exposure pathways including external gamma, terrestrial food chain including food products and drinking water, marine food chain, and inhalation is provided. Radiological doses at each atoll or island are calculated from the average radionuclide concentrations in the terrestrial foods, marine foods, etc. assuming the average daily intake for each food item

  4. Favorable Preliminary Outcomes for Men With Low- and Intermediate-risk Prostate Cancer Treated With 19-Gy Single-fraction High-dose-rate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Krauss, Daniel J., E-mail: dkrauss@beaumont.edu [Oakland University William Beaumont School of Medicine, Royal Oak, Michigan (United States); Ye, Hong [Oakland University William Beaumont School of Medicine, Royal Oak, Michigan (United States); Martinez, Alvaro A. [21st Century Oncology, Farmington Hills, Michigan (United States); Mitchell, Beth; Sebastian, Evelyn; Limbacher, Amy; Gustafson, Gary S. [Oakland University William Beaumont School of Medicine, Royal Oak, Michigan (United States)

    2017-01-01

    Purpose: To report the toxicity and preliminary clinical outcomes of a prospective trial evaluating 19-Gy, single-fraction high-dose-rate (HDR) brachytherapy for men with low- and intermediate-risk prostate cancer. Methods and Materials: A total of 63 patients were treated according to an institutional review board-approved prospective study of single-fraction HDR brachytherapy. Eligible patients had tumor stage ≤T2a, prostate-specific antigen level ≤15 ng/mL, and Gleason score ≤7. Patients with a prostate gland volume >50 cm{sup 3} and baseline American Urologic Association symptom score >12 were ineligible. Patients underwent transrectal ultrasound-guided transperineal implantation of the prostate, followed by single-fraction HDR brachytherapy. Treatment was delivered using {sup 192}Ir to a dose of 19 Gy prescribed to the prostate, with no additional margin applied. Results: Of the 63 patients, 58 had data available for analysis. Five patients had withdrawn consent during the follow-up period. The median follow-up period was 2.9 years (range 0.3-5.2). The median age was 61.4 years. The median gland volume at treatment was 34.8 cm{sup 3}. Of the 58 patients, 91% had T1 disease, 71% had Gleason score ≤6 (29% with Gleason score 7), and the median pretreatment prostate-specific antigen level was 5.1 ng/mL. The acute and chronic grade 2 genitourinary toxicity incidence was 12.1% and 10.3%, respectively. No grade 3 urinary toxicity occurred. No patients experienced acute rectal toxicity grade ≥2, and 2 experienced grade ≥2 chronic gastrointestinal toxicity. Three patients experienced biochemical failure, yielding a 3-year cumulative incidence estimate of 6.8%. Conclusions: Single-fraction HDR brachytherapy is well-tolerated, with favorable preliminary biochemical and clinical disease control rates.

  5. Low-dose (10-Gy) total skin electron beam therapy for cutaneous T-cell lymphoma: an open clinical study and pooled data analysis.

    Science.gov (United States)

    Kamstrup, Maria R; Gniadecki, Robert; Iversen, Lars; Skov, Lone; Petersen, Peter Meidahl; Loft, Annika; Specht, Lena

    2015-05-01

    Cutaneous T-cell lymphomas (CTCLs) are dominated by mycosis fungoides (MF) and Sézary syndrome (SS), and durable disease control is a therapeutic challenge. Standard total skin electron beam therapy (TSEBT) is an effective skin-directed therapy, but the possibility of retreatments is limited to 2 to 3 courses in a lifetime due to skin toxicity. This study aimed to determine the clinical effect of low-dose TSEBT in patients with MF and SS. In an open clinical study, 21 patients with MF/SS stages IB to IV were treated with low-dose TSEBT over dose of 10 Gy in 10 fractions. Data from 10 of these patients were published previously but were included in the current pooled data analysis. Outcome measures were response rate, duration of response, and toxicity. The overall response rate was 95% with a complete cutaneous response or a very good partial response rate (dose (10-Gy) TSEBT offers a high overall response rate and is relatively safe. With this approach, reirradiation at times of relapse or progression is likely to be less toxic than standard dose TSEBT. It remains to be established whether adjuvant and combination treatments can prolong the beneficial effects of low-dose TSEBT. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Effects of high doses of intracoronary adenosine on the assessment of fractional flow reserve

    Directory of Open Access Journals (Sweden)

    Ahmed Khashaba

    2014-03-01

    Conclusions: Intracoronary adenosine, at doses higher than currently suggested, lows obtaining FFR values similar to IV adenosine. Intravenous adenosine, which remains the gold standard, might thus be reserved for those lesions with equivocal FFR values.

  7. High Total Ionizing Dose and Temperature Effects on Micro- and Nano-electronic Devices

    International Nuclear Information System (INIS)

    Gaillardin, M.; Martinez, M.; Paillet, P.; Leray, J.L.; Marcandella, C.; Duhamel, O.; Raine, M.; Richard, N.; Girard, S.; Ouerdane, Y.; Boukenter, A.; Goiffon, V.; Magnan, P.; Andrieu, F.; Barraud, S.; Faynot, O.

    2013-06-01

    This paper investigates the vulnerability of several micro- and nano-electronic technologies to a mixed harsh environment including high total ionizing dose at MGy levels and high temperature. Such operating conditions have been revealed recently for several applications like new security systems in existing or future nuclear power plants, fusion experiments, or deep space missions. In this work, the competing effects already reported in literature of ionizing radiations and temperature are characterized in elementary devices made of MOS transistors from several technologies. First, devices are irradiated using a radiation laboratory X-ray source up to MGy dose levels at room temperature. Devices are grounded during irradiation to simulate a circuit which waits for a wake up signal, representing most of the lifetime of an integrated circuit operating in a harsh environment. Devices are then annealed at several temperatures to discuss the post-irradiation behavior and to determine whether an elevated temperature is an issue or not for circuit function in mixed harsh environments. (authors)

  8. Anti-tumor effect of total body irradiation of low doses on WHT/Ht mice

    International Nuclear Information System (INIS)

    Miyamoto, Miyako; Sakamoto, Kiyohiko

    1987-01-01

    The effect of low dose (0.05 - 1.0 Gy) of total body irradiation (TBI) on non-tumor bearing and tumor bearing mice were investigated. Mice received TBI of 0.1 Gy during 6 - 12 hours before tumor cell inoculation demonstrated to need larger number of tumor cells (approximately 2.5 times) for 50 per cent tumor incidence, compared to recipient mice not to receive TBI. On the other hand, in tumor bearing mice given 0.1 Gy of TBI only tumor cell killing effect was not detected, however enhancement of tumor cell killing effect and prolonged growth delay were observed when tumor bearing mice were treated with 0.1 Gy of TBI in combined with local irradiation on tumors, especially cell killing effect was remarkable in dose range over 6 Gy of local exposure. The mechanism of the effect of 0.1 Gy TBI is considered to be host mediated reactions from the other our experimental results. (author)

  9. Positron emission tomography for the dose monitoring of intra-fractionally moving targets in ion beam therapy

    International Nuclear Information System (INIS)

    Stuetzer, Kristin

    2014-01-01

    Ion beam therapy (IBT) is a promising treatment option in radiotherapy. The characteristic physical and biological properties of light ion beams allow for the delivery of highly tumor conformal dose distributions. Related to the sparing of surrounding healthy tissue and nearby organs at risk, it is feasible to escalate the dose in the tumor volume to reach higher tumor control and survival rates. Remarkable clinical outcome was achieved with IBT for radio-resistant, deep-seated, static and well fixated tumor entities. Presumably, more patients could benefit from the advantages of IBT if it would be available for more frequent tumor sites. Those located in the thorax and upper abdominal region are commonly subjected to intra-fractional, respiration related motion. Different motion-compensated dose delivery techniques have been developed for active field shaping with scanned pencil beams and are at least available under experimental conditions at the GSI Helmholtzzentrum fuer Schwerionenforschung (GSI) in Darmstadt, Germany. Since minor unexpected anatomical changes e.g. related to patient mispositioning, tumour shrinkage or tissue swelling could already lead to remarkable deviations between planned and delivered dose distribution, a valuable dose monitoring system is desired for IBT. So far, positron emission tomography (PET) is the only in vivo, in situ and non-invasive qualitative dose monitoring method applied under clinical conditions. Conclusions about the delivered dose distribution can be drawn indirectly from a comparison between two β + -activity distributions: the measured one and an expected one generated by a Monte-Carlo simulation. Dedicated phantoms mainly made up of polymethyl methacrylate (PMMA) and a motion table for regular one-dimensional (1D) motion patterns have been designed and manufactured for the experiments. Furthermore, the general applicability of the 4D MLEM algorithm for more complex motion patterns has been demonstrated by the

  10. Total dose radiation effects of pressure sensors fabricated on uni-bond-SOI materials

    International Nuclear Information System (INIS)

    Zhu Shiyang; Huang Yiping; Wang Jin; Li Anzhen; Shen Shaoqun; Bao Minhang

    2001-01-01

    Piezoresistive pressure sensors with a twin-island structure were successfully fabricated using high quality Uni-bond-SOI (On Insulator) materials. Since the piezoresistors were structured by the single crystalline silicon overlayer of the SOI wafer and were totally isolated by the buried SiO 2 , the sensors are radiation-hard. The sensitivity and the linearity of the pressure sensors keep their original values after being irradiated by 60 Co γ-rays up to 2.3 x 10 4 Gy(H 2 O). However, the offset voltage of the sensor has a slight drift, increasing with the radiation dose. The absolute value of the offset voltage deviation depends on the pressure sensor itself. For comparison, corresponding polysilicon pressure sensors were fabricated using the similar process and irradiated at the same condition

  11. Characterization of total ionizing dose damage in COTS pinned photodiode CMOS image sensors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zujun, E-mail: wangzujun@nint.ac.cn; Ma, Wuying; Huang, Shaoyan; Yao, Zhibin; Liu, Minbo; He, Baoping; Sheng, Jiangkun; Xue, Yuan [State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an, Shaanxi 710024 (China); Liu, Jing [School of Materials Science and Engineering, Xiangtan University, Hunan (China)

    2016-03-15

    The characterization of total ionizing dose (TID) damage in COTS pinned photodiode (PPD) CMOS image sensors (CISs) is investigated. The radiation experiments are carried out at a {sup 60}Co γ-ray source. The CISs are produced by 0.18-μm CMOS technology and the pixel architecture is 8T global shutter pixel with correlated double sampling (CDS) based on a 4T PPD front end. The parameters of CISs such as temporal domain, spatial domain, and spectral domain are measured at the CIS test system as the EMVA 1288 standard before and after irradiation. The dark current, random noise, dark signal non-uniformity (DSNU), photo response non-uniformity (PRNU), overall system gain, saturation output, dynamic range (DR), signal to noise ratio (SNR), quantum efficiency (QE), and responsivity versus the TID are reported. The behaviors of the tested CISs show remarkable degradations after radiation. The degradation mechanisms of CISs induced by TID damage are also analyzed.

  12. Total-ionizing-dose effects on isolation oxides in modern CMOS technologies

    International Nuclear Information System (INIS)

    Barnaby, Hugh J.; Mclain, Michael; Esqueda, Ivan Sanchez

    2007-01-01

    This paper presents experimental data on the total dose response of deep sub-micron bulk CMOS devices and integrated circuits. Ionizing radiation experiments on shallow trench isolation (STI) field oxide MOS capacitors (FOXCAP) indicate a characteristic build-up of radiation-induced defects in the dielectric. In this paper, capacitors fabricated with STI, thermal, SIMOX and bipolar base oxides of similar thickness are compared and show the STI oxide to be most susceptible to radiation effects. Experimental data on irradiated shift registers and n-channel MOSFETs are also presented. These data indicate that radiation damage to the STI can increase the off-state current of n-channel devices and the standby current of CMOS integrated circuits

  13. New insights into fully-depleted SOI transistor response during total-dose irradiation

    International Nuclear Information System (INIS)

    Schwank, J.R.; Shaneyfelt, M.R.; Dodd, P.E.; Burns, J.A.; Keast, C.L.; Wyatt, P.W.

    1999-01-01

    In this paper, we present irradiation results on 2-fully depleted processes (HYSOI6, RKSOI) that show SOI (silicon on insulator) device response can be more complicated than originally suggested by others. The major difference between the 2 process versions is that the RKSOI process incorporates special techniques to minimize pre-irradiation parasitic leakage current from trench sidewalls. Transistors were irradiated at room temperature using 10 keV X-ray source. Worst-case bias configuration for total-dose testing fully-depleted SOI transistors was found to be process dependent. It appears that the worst-case bias for HYPOI6 process is the bias that causes the largest increase in sidewall leakage. The RKSOI process shows a different response during irradiation, the transition response appears to be dominated by charge trapping in the buried oxide. These results have implications for hardness assurance testing. (A.C.)

  14. Origins of Total-Dose Response Variability in Linear Bipolar Microcircuits

    International Nuclear Information System (INIS)

    Barnaby, H.J.; Cirba, C.R.; Schrimpf, R.D.; Fleetwood, D.M.; Pease, R.L.; Shaneyfelt, Marty R.; Turflinger, T.; Krieg, J.F.; Maher, M.C.

    2000-01-01

    LM1ll voltage comparators exhibit a wide range of total-dose-induced degradation. Simulations show this variability may be a natural consequence of the low base doping of the substrate PNP (SPNP) input transistors. Low base doping increases the SPNP's collector to base breakdown voltage, current gain, and sensitivity to small fluctuations in the radiation-induced oxide defect densities. The build-up of oxide trapped charge (N ot ) and interface traps (N it ) is shown to be a function of pre-irradiation bakes. Experimental data indicate that, despite its structural similarities to the LM111, irradiated input transistors of the LM124 operational amplifier do not exhibit the same sensitivity to variations in pre-irradiation thermal cycles. Further disparities in LM111 and LM124 responses may result from a difference in the oxide defect build-up in the two part types. Variations in processing, packaging, and circuit effects are suggested as potential explanations

  15. High Dose Rate Brachytherapy in Two 9 Gy Fractions in the Treatment of Locally Advanced Cervical Cancer - a South Indian Institutional Experience.

    Science.gov (United States)

    Ghosh, Saptarshi; Rao, Pamidimukkala Bramhananda; Kotne, Sivasankar

    2015-01-01

    Although 3D image based brachytherapy is currently the standard of treatment in cervical cancer, most of the centres in developing countries still practice orthogonal intracavitary brachytherapy due to financial constraints. The quest for optimum dose and fractionation schedule in high dose rate (HDR) intracavitary brachytherapy (ICBT) is still ongoing. While the American Brachytherapy Society recommends four to eight fractions of each less than 7.5 Gy, there are some studies demonstrating similar efficacy and comparable toxicity with higher doses per fraction. To assess the treatment efficacy and late complications of HDR ICBT with 9 Gy per fraction in two fractions. This is a prospective institutional study in Southern India carried on from 1st June 2012 to 31st July 2014. In this period, 76 patients of cervical cancer satisfying our inclusion criteria were treated with concurrent chemo-radiation following ICBT with 9 Gy per fraction in two fractions, five to seven days apart. The median follow-up period in the study was 24 months (range 10.6 - 31.2 months). The 2 year actuarial local control rate, disease-free survival and overall survival were 88.1%, 84.2% and 81.8% respectively. Although 38.2% patients suffered from late toxicity, only 3 patients had grade III late toxicity. In our experience, HDR brachytherapy with 9 Gy per fraction in two fractions is an effective dose fractionation for the treatment of cervical cancer with acceptable toxicity.

  16. Fractionated irradiation and haematopoiesis. Pt. 3

    International Nuclear Information System (INIS)

    Ninkov, V.; Karanovic, D.; Savovski, K.

    1982-01-01

    The effect of total single fractionated irradiation with short time interval on heamatopoietic regeneration of the bone marrow and spleen was investigated. Also, the importance of first dose, when dose of 600 R was divided in two unequal fractions with time interval of 300 s was studied. The investigation was performed on 25 day old rats. The dose of 600 R (X-rays) was divided on: 500 + 100, 400 + 200, 300 + 300, 200 + 400 or 100 + 500 R with time interval of 150, 300 or 600 s. Ten days after irradiation the changes in blood, bone marrow and spleen were observed. After unequal fractionated dose with interval of 600 s slight effect was found. The results after intervals of 600 s and 300 s were significant, when the total dose was divided in two equal doses. The first dose has no promoting role in haematopoietic regeneration when total dose was unequally fractionated. (orig.) [de

  17. The hemodynamic effects of spinal block with low dose of bupivacaine and sufentanil in patients with low myocardial ejection fraction.

    Directory of Open Access Journals (Sweden)

    Mehdi Sanatkar

    2013-07-01

    Full Text Available The aim of this study was to assess the effect of spinal block with low dose of bupivacaine and sufentanil on patients with low cardiac output who underwent lower limb surgery. Fifteen patients who had ejection fraction less than 40% (group 1 were compared with 65 cases with ejection fraction more than 40% (group 2 in our study. Our subjects underwent spinal block with 7.5 mg hyperbaric bupivacaine 0.5% and 5 µg sufentanil. We recorded early events such as hypotension, bradycardia, vasopressor need and ST segment change in our cases. The average mean arterial pressure decreased 13% (110 mmHg to 95.7 mmHg in group 1 and 20% (160 mmHg to 128 mmHg in group 2 (P<0.001. Hypotension due to spinal anesthesia was observed in none of our subjects in both groups and none of our cases need to vasopressor support. All patients remained alert, and no ST segment changes were observed in two groups. In our study none of subjects complained of pain intraoperatively. The subjects were without complaints during the spinal anesthetic in both groups. Spinal block with low dose local anesthetic and sufentanil was a safe and effective method for lower limb surgery in patients with low ejection fraction.

  18. What minimum number of fractions is required with high dose-rate remote afterloading; and reply

    International Nuclear Information System (INIS)

    Orton, C.G.

    1987-01-01

    The author presents 'a more rigorous application of the linear quadratic model for protracted radiotherapy than Dale (1985)' and demonstrates that considerably fewer than 17 fractions are needed, a conclusion particularly relevant to treatment of cancer of the cervix. Dale's reply is based on the tenet that Orton has misquoted the use of the damage repair constants. (UK)

  19. Determination of total antioxidant capacity of milk by CUPRAC and ABTS methods with separate characterisation of milk protein fractions.

    Science.gov (United States)

    Çekiç, Sema Demirci; Demir, Aslı; Başkan, Kevser Sözgen; Tütem, Esma; Apak, Reşat

    2015-05-01

    Most milk-applied antioxidant assays in literature are based on the isolation and quantification of individual antioxidative compounds, whereas total antioxidant capacity (TAC) gives a more holistic picture due to cooperative action of antioxidants. Recently, the cupric reducing antioxidant capacity (CUPRAC) method has been modified to measure the antioxidant capacities of thiol-containing proteins, where the classical ammonium acetate buffer - that may otherwise precipitate proteins- was replaced with concentrated urea buffer (able to expose embedded thiol groups of proteins to oxidative attack) adjusted to pH 7.0. Thus, antioxidant capacity of milk was investigated with two competing TAC assays, namely CUPRAC and ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid))/persulphate, because only these assays were capable of evaluating protein contribution to the observed TAC value. As milk fat caused turbidity, experiments were carried out with skim milk or defatted milk samples. To determine TAC, modified CUPRAC method was applied to whole milk, separated and redissolved protein fractions, and the remaining liquid phase after necessary operations. Both TAC methods were investigated for their dilution sensitivity and antioxidant power assessment of separate milk fractions such as casein and whey. Proteins like β-lactoglobulin and casein (but not simple thiols) exhibited enhanced CUPRAC reactivity with surfactant (SDS) addition. Addition of milk protein fractions to whole skim milk produced significant 'negative-biased' deviations (up to -26% relative standard error) from TAC absorbance additivity in the application of the ABTS method, as opposed to that of the CUPRAC method less affected by chemical deviations from Beer's law thereby producing much smaller deviations from additivity (i.e. the property of additivity is valid when the measured TAC of a mixture is equal to the sum of individual antioxidant capacities of its constituents).

  20. Total organic carbon and humus fractions in restored soils from limestone quarries in semiarid climate, SE Spain

    Science.gov (United States)

    Luna Ramos, Lourdes; Miralles Mellado, Isabel; Ángel Domene Ruiz, Miguel; Solé Benet, Albert

    2016-04-01

    Mining activities generate erosion and loss of plant cover and soil organic matter (SOM), especially in arid and semiarid Mediterranean regions. A precondition for ecosystem restoration in such highly disturbed areas is the development of functional soils with sufficient organic matter. But the SOM quality is also important to long-term C stabilization. The resistance to biodegradation of recalcitrant organic matter fractions has been reported to depend on some intrinsic structural factors of humic acid substances and formation of amorphous organo-mineral recalcitrant complexes. In an experimental soil restoration in limestone quarries in the Sierra de Gádor (Almería), SE Spain, several combinations of organic amendments (sewage sludge and compost from domestic organic waste) and mulches (gravel and woodchip) were added in experimental plots using a factorial design. In each plot, 75 native plants (Anthyllis cytisoides, A. terniflora and Macrochloa tenacissima) were planted and five years after the start of the experiment total organic carbon (TOC), physico-chemical soil properties and organic C fractions (particulate organic matter, H3PO4-fulvic fraction, fulvic acids (FA), humic acids (HA) and humin) were analyzed. We observed significant differences between treatments related to the TOC content and the HA/FA ratio. Compost amendments increased the TOC, HA content and HA/FA ratio, even higher than in natural undisturbed soils, indicating an effective clay humus-complex pointing to progressively increasing organic matter quality. Soils with sewage sludge showed the lowest TOC and HA/FA ratio and accumulated a lower HA proportion indicating poorer organic matter quality and comparatively lower resilience than in natural soils and soils amended with compost.

  1. Estimation of the total effective dose from low-dose CT scans and radiopharmaceutical administrations delivered to patients undergoing SPECT/CT explorations

    International Nuclear Information System (INIS)

    Montes, C.; Hernandez, J.; Gomez-Caminero, F.; Garcia, S.; Martin, C.; Rosero, A.; Tamayo, P.

    2013-01-01

    Hybrid imaging, such as single photon emission computed tomography (SPECT)/CT, is used in routine clinical practice, allowing coregistered images of the functional and structural information provided by the two imaging modalities. However, this multimodality imaging may mean that patients are exposed to a higher radiation dose than those receiving SPECT alone. The study aimed to determine the radiation exposure of patients who had undergone SPECT/CT examinations and to relate this to the Background Equivalent Radiation Time (BERT). 145 SPECT/CT studies were used to estimate the total effective dose to patients due to both radiopharmaceutical administrations and low-dose CT scans. The CT contribution was estimated by the Dose-Length Product method. Specific conversion coefficients were calculated for SPECT explorations. The radiation dose from low-dose CTs ranged between 0.6 mSv for head and neck CT and 2.6 mSv for whole body CT scan, representing a maximum of 1 year of background radiation exposure. These values represent a decrease of 80-85% with respect to the radiation dose from diagnostic CT. The radiation exposure from radiopharmaceutical administration varied from 2.1 mSv for stress myocardial perfusion SPECT to 26 mSv for gallium SPECT in patients with lymphoma. The BERT ranged from 1 to 11 years. The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose. (author)

  2. Radiation therapy in the management of symptomatic bone metastases: the effect of total dose and histology on pain relief and response duration

    International Nuclear Information System (INIS)

    Arcangeli, Giorgio; Giovinazzo, Giuseppe; Saracino, Biancamaria; D'Angelo, Luciano; Giannarelli, Diana; Arcangeli, Giancarlo; Micheli, Adriana

    1998-01-01

    Purpose: In order to better define variables and factors that may influence the pain response to radiation, and to look for a radiation regimen that can assure the highest percentage and the longest duration of pain relief, we performed a prospective, although not randomized, study on patients with bone metastases from various primary sites. Methods and Materials: From December 1988 to March 1994, 205 patients with a total of 255 solitary or multiple bone metastases from several primary tumors were treated in our radiotherapy center with palliative intent. Irradiation fields were treated with three main fractionation schedules: (1) Conventional fractionation: 40-46 Gy/20-23 fractions in 5-5.5 weeks; (2) Short course: 30-36 Gy/10-12 fractions in 2-2.3 weeks; (3) Fast course: 8-28 Gy/1-4 consecutive fractions. Pain intensity was self-assessed by patients using a visual analogic scale graduated from 0 (no pain) to 10 (the strongest pain one can experience). Analgesic requirement was assessed by using a five-point scale, scoring both analgesic strength and frequency (0 = no drug or occasional nonopioids; 1 = Nonopioids once daily; 2 = Nonopioids more than once daily; 3 = Mild opioids (oral codeine, pentazocine, etc.), once daily; 4 = Mild opioids more than once daily; 5 = Strong opioids (morphine, meperidine, etc.). Complete pain relief meant the achievement of a score ≤ 2 in the pain scale or 0 in the analgesic requirement scale. Partial pain relief indicated a score of 3 to 4 or of 1 to 2 on the former and latter scale, respectively. Results: Total pain relief (complete + partial) was observed in 195 (76%) sites, in 158 of which (62%) a complete response was obtained. Metastases from NSC lung tumors appeared to be the least responsive among all primary tumors, with 46% complete pain relief in comparison to 65% and 83% complete relief in breast (p = 0.04) and in prostate metastases (p 0.002), respectively. A significant difference in pain relief was detected among

  3. Three further triterpenoid saponins from Gleditsia caspica fruits and protective effect of the total saponin fraction on cyclophosphamide-induced genotoxicity in mice.

    Science.gov (United States)

    Melek, Farouk R; Aly, Fawzia A; Kassem, Iman A A; Abo-Zeid, Mona A M; Farghaly, Ayman A; Hassan, Zeinab M

    2015-01-01

    Three triterpenoidal saponins were isolated from the saponin fraction derived from a Gleditsia caspica Desf. methanolic fruit extract. The isolated saponins were identified as gleditsiosides B, C, and Q based on spectral data. The saponin-containing fraction was evaluated in vivo for genotoxic and antigenotoxic activities. The fraction caused no DNA damage in Swiss albino male mice treated with a dose of 45 mg/kg body weight for 24 h, although it significantly inhibited the number of chromosomal aberrations induced by cyclophosphamide (CP) in bone marrow and germ cells when applied before or after CP administration. The inhibitory indices in chromosomal aberrations were 59% and 41% for bone marrow and 48% and 43% for germ cells, respectively. In addition, the saponin fraction was found to reduce the viability of the human tumor cell line MCF-7 in a dose-dependent manner with an extrapolated IC50 value in the range of 220 μg/mL.

  4. TOTAL AND FRACTIONAL CONTENTS OF PROTEINS IN BEAN SEEDS UNDER THE CONDITIONS OF VARIED FERTILISATION WITH MICROELEMENTS

    Directory of Open Access Journals (Sweden)

    Wojciech KOZERA

    2013-03-01

    Full Text Available Over 2003-2005 at the Experiment Station at Wierzchucinek at the University of Technology and Life Sciences in Bydgoszcz, there was performed a strict one-factor micro-plot experiment in split-splot design. The factor tested was a type of microelements [n=5: Cu, Zn, Mn, Mo, B]. The microelements were foliar sprayed in a chelated form, as the series of Symfonia fertilizers. The study aimed at comparing the effect of five agricultural-engineering basic microelements on the contents and protein composition of the seeds of Aura cultivar. The fertilization applied, boron and manganese in particular, showed an effect on the increase in the contents of total protein in bean seeds. It also modified the fractional composition of the bean seed protein. There was observed a clear increase in the fraction of albumins and globulins in seeds as a result of the microelements applied, except for boron. The fertilization with molybdenum, boron, copper and zinc reduced the content of glutelins, and the sum of glulelins and prolamines in the bean seeds.

  5. Influence of radioprotectors on total body weight evolution and on oxygen consumption in lethal dose irradiated animals. (Preliminary study)

    International Nuclear Information System (INIS)

    Fatome, M.; Martine, G.; Bargy, E.; Andrieu, L.

    Comparison of total body weight evolution and oxygen consumption in lethal dose irradiated animals, protected by various well known radioprotective substances, isolated or in mixture, with evolution and consumption of non protected animals irradiated at the same dose and with these of check animals [fr

  6. In vivo dosimetry with semiconducting diodes for dose verification in total-body irradiation. A 10-year experience

    International Nuclear Information System (INIS)

    Ramm, U.; Licher, J.; Moog, J.; Scherf, C.; Kara, E.; Boettcher, H.D.; Roedel, C.; Mose, S.

    2008-01-01

    Background and purpose: for total-body irradiation (TBI) using the translation method, dose distribution cannot be computed with computer-assisted three-dimensional planning systems. Therefore, dose distribution has to be primarily estimated based on CT scans (beam-zone method) which is followed by in vivo measurements to ascertain a homogeneous dose delivery. The aim of this study was to clinically establish semiconductor probes as a simple and fast method to obtain an online verification of the dose at relevant points. Patients and methods: in 110 consecutively irradiated TBI patients (12.6 Gy, 2 x 1.8 Gy/day), six semiconductor probes were attached to the body surface at dose-relevant points (eye/head, neck, lung, navel). The mid-body point of the abdomen was defined as dose reference point. The speed of translation was optimized to definitively reach the prescribed dose in this point. Based on the entrance and exit doses, the mid-body doses at the other points were computed. The dose homogeneity in the entire target volume was determined comparing all measured data with the dose at the reference point. Results: after calibration of the semiconductor probes under treatment conditions the dose in selected points and the dose homogeneity in the target volume could be quantitatively specified. In the TBI patients, conformity of calculated and measured doses in the given points was achieved with small deviations of adequate accuracy. The data of 80% of the patients are within an uncertainty of ± 5%. Conclusion: during TBI using the translation method, dose distribution and dose homogeneity can be easily controlled in selected points by means of semiconductor probes. Semiconductor probes are recommended for further use in the physical evaluation of TBI. (orig.)

  7. Chemical attributes, total organic carbon stock and humified fractions of organic matter soil submitted to different systems of sugarcane management

    Directory of Open Access Journals (Sweden)

    Jean Sérgio Rosset

    2014-10-01

    Full Text Available Mechanized harvesting maintenance of trash from cane sugar and soil application of waste as vinasse and filter cake can improve the system of crop yield. Thus, this study aimed to evaluate the changes in the chemical, the stock of total organic carbon and humified organic matter fractions in an Oxisol cultivated with cane sugar with the following management systems: with sugarcane vinasse application (CCV, without application of burnt cane waste (CQS, with burnt cane vinasse application (CQV, with application of burnt cane filter cake (CQTF and burnt cane with joint application of vinasse and filter cake (CQVTF. For reference we used an area of natural vegetation (NV, Cerrado sensu stricto. Treatment CQVTF showed improvement in soil chemical properties, increased inventory levels of total organic carbon – TOC (values ranging from 21.28 to 40.02 Mg ha-1 and humified fractions of soil organic matter in relation to other treatments. The CQS area at a depth of 0-0.05 m, showed the greatest losses of soil TOC stocks (56.3% compared to NV. The adoption of management presented CCV and chemical attributes of the soil TOC stocks equivalent to those observed in areas with CQV CQTF and despite the short period of adoption (3 years. The TOC correlated with the sum of bases (r = 0.76 **, cation exchange capacity (r = 0.59 ** and base saturation (r = 0.63 **, while the humic acids (r = 0.40 ** fulvic acids (r = 0.49 ** and humin (r = 0.59 ** correlated with the cation exchange capacity of the soil. These results indicate that the preservation of trash in the management of cane sugar added to the application of vinasse and filter cake increases the TOC stocks promoting improvement in soil chemical properties.

  8. Relative effect of dose-rate values and fractionation on late responding tissues and tumours

    International Nuclear Information System (INIS)

    Malgieri, F.

    1995-01-01

    There are currently available different facilities for radiotherapy also with regard to the dose-rate values (in the ranges LDR - MDR - HDR), sometimes used alternatively or subsequently for the same tumour. We have set up a 'unitary' L-Q model, based on Liversage's and Dale's works, that explicitly include also the dose-rate value and a correction factor of the β parameter depending on the sublethal damage repair time constant, on the length of time of each irradiation and on the time interval between following irradiation for to realize the effect of the incomplete repair when the time interval is short as, for example, in the PLDR. This 'unitary' L-Q model is, of course, usable in the same way both for external beam therapy and for curietherapy and make possible to compute and compare, for each kind of tumour and normal tissue, the relative effect of the different available modality of radiotherapy also with regard to the dose-rate. We show and discuss the resulting relationships of the ratio BED 'late'/BED tumour changing the time-dose parameters and the values of the biological characteristic parameters T p , α/β and μ, for defined size of tumour control and different value of the doserate

  9. Low-Dose Total Skin Electron Beam Therapy as a Debulking Agent for Cutaneous T-Cell Lymphoma: An open-label prospective phase II study

    DEFF Research Database (Denmark)

    Kamstrup, M R; Lindahl, Lise Maria; Gniadecki, R

    2012-01-01

    Background: Total skin electron beam therapy (TSEBT) is a powerful treatment for cutaneous T-cell lymphomas (CTCL). Based on the occurrence of relapses with low radiation doses, doses of 30-36 Gy are commonly used but most patients still eventually relapse and repeat treatment courses are limited...... due to the cumulative toxicity. Complete response rates are about 60-90% for T2-4 stages with a 5-year relapse-free survival of 10-25% for stages IB-III. Objectives: To evaluate prospectively the efficacy of low-dose TSEBT (10 Gy) in terms of complete cutaneous response rate, overall response rate...... and response duration in CTCL. Methods: Ten patients with stage IB-IV mycosis fungoides (MF) were treated in an open-label manner with 4 fractions of 1 Gy/week TSEB to a total skin dose of 10 Gy. Treatment responses were assessed at 1 and 3 months after treatment and subsequently at least every 6 months...

  10. Fractionated dose skews differentiation of Glial progenitor cells into immature oligodendrocytes and astrocytes, with lower mature oligodendrocytes formation, as compared to singe low dose of low and high LET radiation

    International Nuclear Information System (INIS)

    Sanchez, Zina; Pena, Louis; Naidu, Mamta

    2010-01-01

    In the proposed study, the effect of fractionated, low dose versus single low dose of low LET X-rays and charged particles on induction of base excision repair enzyme Apurinic Endonuclease-1 (Ape1) are determined, which is known to inhibit cell differentiation, and found that at lower doses of 10,25 and 50 cGy there was a very significant induction of Apel which correlated to number of fractions, whereas at 100 cGy this induction was significantly lower. Also, there was a clear correlation between increase in fractions and higher immature OL and astrocyte formation

  11. TU-F-CAMPUS-T-01: Dose and Energy Spectra From Neutron Induced Radioactivity in Medical Linear Accelerators Following High Energy Total Body Irradiation

    International Nuclear Information System (INIS)

    Keehan, S; Taylor, M; Franich, R; Smith, R; Dunn, L; Kron, T

    2015-01-01

    Purpose: To assess the risk posed by neutron induced activation of components in medical linear accelerators (linacs) following the delivery of high monitor unit 18 MV photon beams such as used in TBI. Methods: Gamma spectroscopy was used to identify radioisotopes produced in components of a Varian 21EX and an Elekta Synergy following delivery of photon beams. Dose and risk estimates for TBI were assessed using dose deliveries from an actual patient treatment. A 1 litre spherical ion chamber (PTW, Germany) has been used to measure the dose at the beam exit window and at the total body irradiation (TBI) treatment couch following large and small field beams with long beam-on times. Measurements were also made outside of the closed jaws to quantify the benefit of the attenuation provided by the jaws. Results: The radioisotopes produced in the linac head have been identified as 187 W, 56 Mn, 24 Na and 28 Al, which have half-lives from between 2.3 min to 24 hours. The dose at the beam exit window following an 18 MV 2197 MU TBI beam delivery was 12.6 µSv in ten minutes. The dose rate at the TBI treatment couch 4.8 m away is a factor of ten lower. For a typical TBI delivered in six fractions each consisting of four beams and an annual patient load of 24, the annual dose estimate for a staff member at the treatment couch for ten minutes is 750 µSv. This can be further reduced by a factor of about twelve if the jaws are closed before entering the room, resulting in a dose estimate of 65 µSv. Conclusion: The dose resulting from the activation products for a representative TBI workload at our clinic of 24 patients per year is 750 µSv, which can be further reduced to 65 µSv by closing the jaws

  12. Synergistic effects of total ionizing dose on single event upset sensitivity in static random access memory under proton irradiation

    International Nuclear Information System (INIS)

    Xiao Yao; Guo Hong-Xia; Zhang Feng-Qi; Zhao Wen; Wang Yan-Ping; Zhang Ke-Ying; Ding Li-Li; Luo Yin-Hong; Wang Yuan-Ming; Fan Xue

    2014-01-01

    Synergistic effects of the total ionizing dose (TID) on the single event upset (SEU) sensitivity in static random access memories (SRAMs) were studied by using protons. The total dose was cumulated with high flux protons during the TID exposure, and the SEU cross section was tested with low flux protons at several cumulated dose steps. Because of the radiation-induced off-state leakage current increase of the CMOS transistors, the noise margin became asymmetric and the memory imprint effect was observed. (interdisciplinary physics and related areas of science and technology)

  13. Total dose and dose-rate effects on start-up current in anti-fuse FPGA

    International Nuclear Information System (INIS)

    Wang, J.; Wong, W.; McCollum, J.; Cronquist, B.; Katz, R.; Kleyner, I.; Kleyner, F.

    1999-01-01

    Radiation enhanced start-up current (RESC) in an anti-fuse FPGA, A1280A, is thoroughly investigated and a comprehensive transistor-level mechanism is proposed. Low dose-rate testing, appropriate for civilian space applications, and annealing at room temperature shows RESC to be negligible for the lot of parts tested with a fixed power supply slew rate. (authors)

  14. A generalised formulation of the 'incomplete-repair' model for cell survival and tissue response to fractionated low dose-rate irradiation

    International Nuclear Information System (INIS)

    Nilsson, P.; Joiner, M.C.

    1990-01-01

    A generalized equation for cell survival or tissue effects after fractionated low dose-rate irradiations, when there is incomplete repair between fractions and significant repair during fractions, is derived in terms of the h- and g-functions of the 'incomplete-repair' (IR) model. The model is critically dependent on α/β, repair half-time, treatment time and interfraction interval, and should therefore be regarded primarily as a tool for the analysis of fractionation and dose-rate effects in carefully designed radiobiological experiments, although it should also be useful in exploring, in a general way, the feasibility of clinical treatment protocols using fractionated low dose-rate treatments. (author)

  15. Attached, unattached fraction of progeny concentrations and equilibrium factor for dose assessments from {sup 222}Rn and {sup 220}Rn

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Parminder; Saini, Komal; Bajwa, Bikramjit Singh [Guru Nanak Dev University, Department of Physics, Amritsar, Punjab (India); Mishra, Rosaline; Sahoo, Bijay Kumar [Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai (India)

    2016-08-15

    In this study, measurements of indoor radon ({sup 222}Rn), thoron ({sup 220}Rn) and their equilibrium equivalent concentration (EEC) were carried out in 96 dwellings from 22 different villages situated in Hamirpur district, Himachal Pradesh, India, by using LR-115 type II-based pinhole twin cup dosimeters and deposition-based progeny sensors (DRPS/DTPS). The annual average indoor {sup 222}Rn and {sup 220}Rn concentrations observed in these dwellings were 63.82 and 89.59 Bq/m{sup 3}, respectively, while the average EEC (attached + unattached) for {sup 222}Rn and {sup 220}Rn was 29.28 and 2.74 Bq/m{sup 3}. For {sup 222}Rn (f{sub Rn}) and {sup 220}Rn (f{sub Tn}), the average values of unattached fraction were 0.11 and 0.09, respectively. The equilibrium factors for radon (F{sub Rn}) and thoron (F{sub Tn}) varied from 0.12 to 0.77 with an average of 0.50, and from 0.01 to 0.34 with an average of 0.05, respectively. The annual inhalation dose due to mouth and nasal breathing was calculated using dose conversion factors and unattached fractions. The indoor annual effective doses for {sup 222}Rn (AEDR) and {sup 220}Rn (AEDT) were found to be 1.92 and 0.83 mSv a{sup -1}, respectively. The values of {sup 222}Rn/{sup 220}Rn concentrations and annual effective doses obtained in the present study are within the safe limits as recommended by the International Commission on Radiological Protection for indoor dwelling exposure conditions. (orig.)

  16. Expression profiling of murine lung 70 days following exposure to fractionated or acute dose of 1.0 Gy 56Fe- particle irradiation

    Data.gov (United States)

    National Aeronautics and Space Administration — Irradiation of the K-rasLA1 mouse model with a fractionated dose of 1.0Gy 56Fe- particles increases the incidence of invasive carcinoma compared to unirradiated...

  17. SU-F-T-327: Total Body Irradiation In-Vivo Dose Measurements Using Optically Stimulated Luminescence (OSL) NanoDots and Farmer Type Ion Chamber

    International Nuclear Information System (INIS)

    Kaur, H; Kumar, S; Sarkar, B; Ganesh, T; Giri, U; Jassal, K; Rathinamuthu, S; Gulia, G; Gopal, V; Mohanti, B; Munshi, A

    2016-01-01

    Purpose: This study was performed to analyze the agreement between optically stimulated luminescence (OSL) nanoDots measured doses and 0.6 cc Farmer type ionization chamber measured doses during total body irradiation (TBI). Methods: In-vivo dose measurements using OSL nanoDots and Farmer chamber were done in a total of twelve patients who received TBI at our center by bilateral parallel-opposed beams technique. In this technique, the patient is kept inside the TBI box which is filled with rice bags and irradiated using two bilateral parallel opposed beams of 40×40 cm"2 size with 45° collimator rotation at an SSD of 333.5 cm in an Elekta Synergy linear accelerator. All patients received a dose of 2 Gy in single fraction as conditioning regimen. The beams were equally weighted at the midplane of the box. The nanoDots were placed over forehead, right and left neck, right and left lung, umbilicus, right and left abdomen, medial part of thigh, knee and toe. A 0.6 cc Farmer chamber was placed in between the thighs of the patient. Measured doses are reported along with the statistical comparisons using paired sample t-test. Results: For the above sites the mean doses were 212.2±21.1, 218.2±7.6, 218.7±9.3, 215.6±9.5, 217.5±11.5, 214.5±7.7, 218.3±6.8, 221.5±15, 229.1±11.0, 220.5±7.7 and 223.3±5.1 cGy respectively. For all OSL measurements the mean dose was 218.6±11.8 cGy. Farmer chamber measurements yielded a mean dose of 208.8±15.6 cGy. Statistical analysis revealed that there was no significant difference between OSL measured doses in forehead, right and left neck, right and left lung, umbilicus, right and left abdomen and toe and Farmer chamber measured doses (0.72≤p≤0.06). However the mean OSL doses at thigh and knee were statistically different (p<0.05) from the Farmer chamber measurements. Conclusion: OSL measurements were found to be in agreement with Farmer type ionization chamber measurements in in-vivo dosimetry of TBI.

  18. SU-F-T-327: Total Body Irradiation In-Vivo Dose Measurements Using Optically Stimulated Luminescence (OSL) NanoDots and Farmer Type Ion Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, H; Kumar, S; Sarkar, B; Ganesh, T; Giri, U; Jassal, K; Rathinamuthu, S; Gulia, G; Gopal, V; Mohanti, B; Munshi, A [Fortis Memorial Research Institute, Gurgaon, Haryana (India)

    2016-06-15

    Purpose: This study was performed to analyze the agreement between optically stimulated luminescence (OSL) nanoDots measured doses and 0.6 cc Farmer type ionization chamber measured doses during total body irradiation (TBI). Methods: In-vivo dose measurements using OSL nanoDots and Farmer chamber were done in a total of twelve patients who received TBI at our center by bilateral parallel-opposed beams technique. In this technique, the patient is kept inside the TBI box which is filled with rice bags and irradiated using two bilateral parallel opposed beams of 40×40 cm{sup 2} size with 45° collimator rotation at an SSD of 333.5 cm in an Elekta Synergy linear accelerator. All patients received a dose of 2 Gy in single fraction as conditioning regimen. The beams were equally weighted at the midplane of the box. The nanoDots were placed over forehead, right and left neck, right and left lung, umbilicus, right and left abdomen, medial part of thigh, knee and toe. A 0.6 cc Farmer chamber was placed in between the thighs of the patient. Measured doses are reported along with the statistical comparisons using paired sample t-test. Results: For the above sites the mean doses were 212.2±21.1, 218.2±7.6, 218.7±9.3, 215.6±9.5, 217.5±11.5, 214.5±7.7, 218.3±6.8, 221.5±15, 229.1±11.0, 220.5±7.7 and 223.3±5.1 cGy respectively. For all OSL measurements the mean dose was 218.6±11.8 cGy. Farmer chamber measurements yielded a mean dose of 208.8±15.6 cGy. Statistical analysis revealed that there was no significant difference between OSL measured doses in forehead, right and left neck, right and left lung, umbilicus, right and left abdomen and toe and Farmer chamber measured doses (0.72≤p≤0.06). However the mean OSL doses at thigh and knee were statistically different (p<0.05) from the Farmer chamber measurements. Conclusion: OSL measurements were found to be in agreement with Farmer type ionization chamber measurements in in-vivo dosimetry of TBI.

  19. A model of cardiovascular disease giving a plausible mechanism for the effect of fractionated low-dose ionizing radiation exposure.

    Directory of Open Access Journals (Sweden)

    Mark P Little

    2009-10-01

    Full Text Available Atherosclerosis is the main cause of coronary heart disease and stroke, the two major causes of death in developed society. There is emerging evidence of excess risk of cardiovascular disease at low radiation doses in various occupationally exposed groups receiving small daily radiation doses. Assuming that they are causal, the mechanisms for effects of chronic fractionated radiation exposures on cardiovascular disease are unclear. We outline a spatial reaction-diffusion model for atherosclerosis and perform stability analysis, based wherever possible on human data. We show that a predicted consequence of multiple small radiation doses is to cause mean chemo-attractant (MCP-1 concentration to increase linearly with cumulative dose. The main driver for the increase in MCP-1 is monocyte death, and consequent reduction in MCP-1 degradation. The radiation-induced risks predicted by the model are quantitatively consistent with those observed in a number of occupationally-exposed groups. The changes in equilibrium MCP-1 concentrations with low density lipoprotein cholesterol concentration are also consistent with experimental and epidemiologic data. This proposed mechanism would be experimentally testable. If true, it also has substantive implications for radiological protection, which at present does not take cardiovascular disease into account. The Japanese A-bomb survivor data implies that cardiovascular disease and cancer mortality contribute similarly to radiogenic risk. The major uncertainty in assessing the low-dose risk of cardiovascular disease is the shape of the dose response relationship, which is unclear in the Japanese data. The analysis of the present paper suggests that linear extrapolation would be appropriate for this endpoint.

  20. Establishment of a paediatric age-related reference interval for the measurement of urinary total fractionated metanephrines.

    LENUS (Irish Health Repository)

    Griffin, Alison

    2012-02-01

    INTRODUCTION: Normetanephrine and metanephrine are intermediate metabolites of noradrenaline and adrenaline metabolism. To assess whether normetanephrine and metanephrine analysis may aid in the diagnosis of Neuroblastoma, a reference interval for these metabolites must first be established. AIM: The overall aim of this study was to establish a paediatric age-related reference interval for the measurement of total fractionated metanephrines. METHODS: A total of 267 urine samples were analysed following acid hydrolysis. This releases the metanephrines from their sulphate-bound metabolites. The samples were analysed using reverse phase high-performance liquid chromatography with electro-chemical detection on a Gilson automated sequential trace enrichment of dialysate sample system. RESULTS: Data were analysed using Minitab Release version 14. Outliers were removed using the Dixon\\/Reed one-third rule. Partitioning of the age groups was achieved using Harris and Boyd\\'s standard normal deviate test. Non-parametric analysis of the data was performed, followed by the establishment of the 2.5th and the 97.5th reference limits. CONCLUSIONS: The established reference intervals are described in Table 2.

  1. THE CHANGE OF TOTAL PROTEIN FRACTION OF MUSCLE TISSUE OF PORK WITH BIO- AND PHYSICO-CHEMICAL SPECIFIC IN THE PROCESS OF COOKING AT DIFFERENT TEMPERATURES

    Directory of Open Access Journals (Sweden)

    O. Shalimova

    2012-03-01

    Full Text Available The character of changes in total protein fraction of muscle tissue of pork with PSE defects in the process of cooking at temperatures ranging from 40 to 72 g.C in steps of 2 g.C is investigated. Our studies have revealed differences in the change of state the total fraction of muscle proteins with defects PSE pork during cooking.

  2. Doses and fractionation schemes to be employed in clinical trials of high-LET radiations

    International Nuclear Information System (INIS)

    Fowler, J.F.

    1979-01-01

    An improvement in local tumour control of 20% would require 2 x 130 cases in order that nine trials out of ten should show the difference at a significant level. If the improvement is 30% only 2 x 55 patients are required. However, the detection of increased normal tissue complications requires larger number of patients than this, e.g. 2 x 150 if the increase is from 5% to 15%. The use of two dose levels on the neutron side in a clinical trial would enable definitive data to be obtained in, say, 6 years with 300 patients, instead of 10 years with 400 patients if only one dose level were used. (author)

  3. Laboratory Bioaccumulation, Depuration And Total Dose Rate Of Waterborne Th-232 In Freshwater Fish Of Anabas Testudineus

    International Nuclear Information System (INIS)

    Zal U'yun Wan Mahmood; Norfaizal Mohamed; Nita Salina Abu Bakar

    2014-01-01

    Preliminary results on the study of bioaccumulation, depuration and total dose rate of Th-232 in the whole body of Anabas testudineus are presented. The objective of this study was to evaluate the effect of Th-232 concentration activity on the laboratory bioaccumulation, depuration and total dose rate in Anabas testudineus. Anabas testudineus adults were exposed to different waterborne Th-232 levels: 0 BqL -1 (control), 50 BqL -1 and 100 BqL -1 for 30 day (uptake phase), followed by exposure to radionuclide-free water for 30 days (loss phase). Radionuclide concentration ratios between the whole body levels and water levels, percentage of Th-232 remaining in fish were calculated and total dose rates using ERICA Assessment Tool were also estimated. The results showed the increase of waterborne Th-232 concentration corresponded to a progressive increase of Th accumulation and total dose rate (internal and external) in the whole body of Anabas testudineus. Considering the ERICA dose rate screening value of 10 μGyh -1 , the findings can be concluded the estimated of total dose rate (< 5 μGyh -1 ) in Anabas testudineus is in order of small magnitude. Nevertheless, these preliminary results showed that the Anabas testudineus has a potential to accumulate thorium. (author)

  4. High-dose-rate brachytherapy as monotherapy delivered in two fractions within one day for favorable/intermediate-risk prostate cancer: preliminary toxicity data.

    Science.gov (United States)

    Ghilezan, Michel; Martinez, Alvaro; Gustason, Gary; Krauss, Daniel; Antonucci, J Vito; Chen, Peter; Fontanesi, James; Wallace, Michelle; Ye, Hong; Casey, Alyse; Sebastian, Evelyn; Kim, Leonard; Limbacher, Amy

    2012-07-01

    To report the toxicity profile of high-dose-rate (HDR)-brachytherapy (BT) as monotherapy in a Human Investigation Committee-approved study consisting of a single implant and two fractions (12 Gy × 2) for a total dose of 24 Gy, delivered within 1 day. The dose was subsequently increased to 27 Gy (13.5 Gy × 2) delivered in 1 day. We report the acute and early chronic genitourinary and gastrointestinal toxicity. A total of 173 patients were treated between December 2005 and July 2010. However, only the first 100 were part of the IRB-approved study and out of these, only 94 had a minimal follow-up of 6 months, representing the study population for this preliminary report. All patients had clinical Stage T2b or less (American Joint Committee on Cancer, 5th edition), Gleason score 6-7 (3+4), and prostate-specific antigen level of ≤12 ng/mL. Ultrasound-guided HDR-BT with real-time dosimetry was used. The prescription dose was 24 Gy for the first 50 patients and 27 Gy thereafter. The dosimetric goals and constraints were the same for the two dose groups. Toxicity was scored using the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3. The highest toxicity scores encountered at any point during follow-up are reported. The median follow-up was 17 months (range, 6-40.5). Most patients had Grade 0-1 acute toxicity. The Grade 2 acute genitourinary toxicity was mainly frequency/urgency (13%), dysuria (5%), hematuria, and dribbling/hesitancy (2%). None of the patients required a Foley catheter at any time; however, 8% of the patients experienced transient Grade 1 diarrhea. No other acute gastrointestinal toxicities were found. The most common chronic toxicity was Grade 2 urinary frequency/urgency in 16% of patients followed by dysuria in 4% of patients; 2 patients had Grade 2 rectal bleeding and 1 had Grade 4, requiring laser treatment. Favorable-risk prostate cancer patients treated with a single implant HDR-BT to 24-27 Gy in two fractions

  5. High-Dose-Rate Brachytherapy as Monotherapy Delivered in Two Fractions Within One Day for Favorable/Intermediate-Risk Prostate Cancer: Preliminary Toxicity Data

    Energy Technology Data Exchange (ETDEWEB)

    Ghilezan, Michel, E-mail: mghilezan@beaumont.edu [Department of Radiation Oncology, William Beaumont Hospital and Rose Cancer Institute, Royal Oak, Michigan (United States); Martinez, Alvaro; Gustason, Gary; Krauss, Daniel; Antonucci, J. Vito; Chen, Peter; Fontanesi, James; Wallace, Michelle; Ye Hong; Casey, Alyse; Sebastian, Evelyn; Kim, Leonard; Limbacher, Amy [Department of Radiation Oncology, William Beaumont Hospital and Rose Cancer Institute, Royal Oak, Michigan (United States)

    2012-07-01

    Purpose: To report the toxicity profile of high-dose-rate (HDR)-brachytherapy (BT) as monotherapy in a Human Investigation Committee-approved study consisting of a single implant and two fractions (12 Gy Multiplication-Sign 2) for a total dose of 24 Gy, delivered within 1 day. The dose was subsequently increased to 27 Gy (13.5 Gy Multiplication-Sign 2) delivered in 1 day. We report the acute and early chronic genitourinary and gastrointestinal toxicity. Methods and Materials: A total of 173 patients were treated between December 2005 and July 2010. However, only the first 100 were part of the IRB-approved study and out of these, only 94 had a minimal follow-up of 6 months, representing the study population for this preliminary report. All patients had clinical Stage T2b or less (American Joint Committee on Cancer, 5th edition), Gleason score 6-7 (3+4), and prostate-specific antigen level of {<=}12 ng/mL. Ultrasound-guided HDR-BT with real-time dosimetry was used. The prescription dose was 24 Gy for the first 50 patients and 27 Gy thereafter. The dosimetric goals and constraints were the same for the two dose groups. Toxicity was scored using the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3. The highest toxicity scores encountered at any point during follow-up are reported. Results: The median follow-up was 17 months (range, 6-40.5). Most patients had Grade 0-1 acute toxicity. The Grade 2 acute genitourinary toxicity was mainly frequency/urgency (13%), dysuria (5%), hematuria, and dribbling/hesitancy (2%). None of the patients required a Foley catheter at any time; however, 8% of the patients experienced transient Grade 1 diarrhea. No other acute gastrointestinal toxicities were found. The most common chronic toxicity was Grade 2 urinary frequency/urgency in 16% of patients followed by dysuria in 4% of patients; 2 patients had Grade 2 rectal bleeding and 1 had Grade 4, requiring laser treatment. Conclusions: Favorable

  6. High-Dose-Rate Brachytherapy as Monotherapy Delivered in Two Fractions Within One Day for Favorable/Intermediate-Risk Prostate Cancer: Preliminary Toxicity Data

    International Nuclear Information System (INIS)

    Ghilezan, Michel; Martinez, Alvaro; Gustason, Gary; Krauss, Daniel; Antonucci, J. Vito; Chen, Peter; Fontanesi, James; Wallace, Michelle; Ye Hong; Casey, Alyse; Sebastian, Evelyn; Kim, Leonard; Limbacher, Amy

    2012-01-01

    Purpose: To report the toxicity profile of high-dose-rate (HDR)-brachytherapy (BT) as monotherapy in a Human Investigation Committee-approved study consisting of a single implant and two fractions (12 Gy × 2) for a total dose of 24 Gy, delivered within 1 day. The dose was subsequently increased to 27 Gy (13.5 Gy × 2) delivered in 1 day. We report the acute and early chronic genitourinary and gastrointestinal toxicity. Methods and Materials: A total of 173 patients were treated between December 2005 and July 2010. However, only the first 100 were part of the IRB-approved study and out of these, only 94 had a minimal follow-up of 6 months, representing the study population for this preliminary report. All patients had clinical Stage T2b or less (American Joint Committee on Cancer, 5th edition), Gleason score 6-7 (3+4), and prostate-specific antigen level of ≤12 ng/mL. Ultrasound-guided HDR-BT with real-time dosimetry was used. The prescription dose was 24 Gy for the first 50 patients and 27 Gy thereafter. The dosimetric goals and constraints were the same for the two dose groups. Toxicity was scored using the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3. The highest toxicity scores encountered at any point during follow-up are reported. Results: The median follow-up was 17 months (range, 6–40.5). Most patients had Grade 0-1 acute toxicity. The Grade 2 acute genitourinary toxicity was mainly frequency/urgency (13%), dysuria (5%), hematuria, and dribbling/hesitancy (2%). None of the patients required a Foley catheter at any time; however, 8% of the patients experienced transient Grade 1 diarrhea. No other acute gastrointestinal toxicities were found. The most common chronic toxicity was Grade 2 urinary frequency/urgency in 16% of patients followed by dysuria in 4% of patients; 2 patients had Grade 2 rectal bleeding and 1 had Grade 4, requiring laser treatment. Conclusions: Favorable-risk prostate cancer patients treated with

  7. [Single intravenous tranexamic acid dose to reduce blood loss in primary total knee replacement].

    Science.gov (United States)

    Sanz-Reig, J; Parra Ruiz, B; Ferrández Martínez, J; Martínez López, J F

    2016-01-01

    To evaluate the effectiveness and safety of a single intravenous dose of tranexamic acid in order to reduce blood loss in total knee replacement. Prospective observational study of the administration of tranexamic acid in patients undergoing primary total knee arthroplasty from November 2013 to February 2015, in which an autologous blood recovery system was used. The study included 98 patients, distributed into two groups of 49 patients according to whether or not they received intravenous tranexamic acid. The primary endpoint was the number of patients requiring autologous transfusion from the recovery system autologous blood recovery system. No drop-outs were recorded during follow-up. There were no significant differences between groups as regards the preoperative and hospital variables. The mean preoperative haemoglobin and haematocrit at 24 and 48 hours postoperatively were similar in both groups. The average volume of bleeding in the autologous blood recovery system and estimated average blood loss was lower in patients who had been administered tranexamic acid, with significant differences. No patients in the group that was administered tranexamic acid required blood autotransfusion. The transfusion rate was zero in the two groups. No adverse events related to the administration of tranexamic acid were recorded. Intravenous administration of tranexamic acid, according to the described protocol, has presented a non-autotransfusion or allo-transfusion rate of 100%, with no increased incidence of thrombotic events. Thus, its use in this group of patients is recommended. The indication should be individualized, its use justified in the patient medical records, and informed consent is mandatory. Copyright © 2015 SECOT. Published by Elsevier Espana. All rights reserved.

  8. High-Dose-Rate Brachytherapy of a Single Implant With Two Fractions Combined With External Beam Radiotherapy for Hormone-Naive Prostate Cancer

    International Nuclear Information System (INIS)

    Sato, Morio; Mori, Takashi; Shirai, Shintaro; Kishi, Kazushi; Inagaki, Takeshi; Hara, Isao

    2008-01-01

    Purpose: To evaluate the preliminary outcomes of high-dose-rate (HDR) brachytherapy of a single implant with two fractions and external beam radiotherapy (EBRT) for hormone-naive prostate cancer. Methods and Materials: Between March 2000 and Sept 2003, a total of 53 patients with tumor Stage T1c-T3b N0 M0 prostate cancer were treated with HDR brachytherapy boost doses (7.5 Gy/fraction) and 50-Gy EBRT during a 5.5-week period. Median follow-up was 61 months. Patients were divided into groups with localized (T1c-T2b) and advanced disease (T3a-T3b). We used the American Society for Therapeutic Radiology and Oncology (ASTRO) definition for biochemical failure. According to recommendations of the Radiation Therapy Oncology Group-ASTRO Phoenix Consensus Conference, biochemical failure-free control rates (BF-FCRs) at 3 years were investigated as 2 years short of the median follow-up. Results: Between April 2000 and Sept 2007, Common Terminology Criteria for Adverse Events Version 2.0 late Grade 2 genitourinary and gastrointestinal toxicity rates were 0% and 3.8%, respectively. Erectile preservation was 25% at 5 years. Overall survival was 88.1% and cause-specific survival was 100%. At 3 years, ASTRO BF-FCRs of the localized and advanced groups were 100% and 42%, respectively (p = 0.001). Conclusions: The HDR brachytherapy of a single implant with two fractions plus EBRT is effective in treating patients with localized hormone-naive prostate cancer, with the least genitourinary and gastrointestinal toxicities; however, longer median BF-FCR follow-up is required to assess these findings

  9. Effect of high-dose preoperative methylprednisolone on recovery after total hip arthroplasty

    DEFF Research Database (Denmark)

    Lunn, T H; Andersen, Lasse Østergaard; Kristensen, B B

    2013-01-01

    (IQR) (95% CI), MP vs placebo]: 23.5 (23.3-23.7) (17.8-43.8) vs 23.5 (23.0-23.8) (20.0-46.8) h, the mean difference (95% CI) being -1.3 (-4.7 to 2.2) h, P=0.65. Overall pain for the first 24 h after surgery was significantly reduced in the MP vs the placebo group (PMP 125 mg i.v. before surgery added......BACKGROUND: /st>High-dose glucocorticoid may reduce postsurgical pain and improve recovery. We hypothesized that 125 mg methylprednisolone (MP) would reduce time to meet functional discharge criteria after total hip arthroplasty (THA). METHODS: /st>Forty-eight patients undergoing unilateral THA...... under spinal anaesthesia were consecutively included in this randomized, double-blind, placebo-controlled trial receiving preoperative i.v. MP or saline. All patients received a standardized, multimodal analgesic regime with paracetamol, celecoxib, and gabapentin. The primary outcome was time to meet...

  10. Total Ionizing Dose effects in 130-nm commercial CMOS technologies for HEP experiments

    CERN Document Server

    Gonella, L; Silvestri, M; Gerardin, S; Pantano, D; Re, V; Manghisoni, M; Ratti, L; Ranieri, A

    2007-01-01

    The impact of foundry-to-foundry variability and bias conditions during irradiation on the Total Ionizing Dose (TID) response of commercial 130-nm CMOS technologies have been investigated for applications in High Energy Physics (HEP) experiments. n- and p-channel MOSFETs from three different manufacturers have been irradiated with X-rays up to more than 100 Mrad (SiO2). Even though the effects of TID are qualitatively similar, the amount of degradation is shown to vary considerably from foundry to foundry, probably depending on the processing of the STI oxide and/or doping profile in the substrate. The bias during irradiation showed to have a strong impact as well on the TID response, proving that exposure at worst case bias conditions largely overestimates the degradation a device may experience during its lifetime. Overall, our results increase the confidence that 130-nm CMOS technologies can be used in future HEP experiments even without Hardness-By-Design solutions, provided that constant monitoring of th...

  11. Fractionated stereotactic radiation therapy and single high-dose radiosurgery for acoustic neuroma: early results of a prospective clinical study

    International Nuclear Information System (INIS)

    Meijer, O.W.M.; Wolbers, J.G.; Baayen, J.C.; Slotman, B.J.

    2000-01-01

    Purpose: To prospectively assess the local control and toxicity rate in acoustic neuroma patients treated with linear accelerator-based radiosurgery and fractionated stereotactic radiation therapy. Methods and Materials: We evaluated 37 consecutive patients treated with stereotactic radiation therapy for acoustic neuroma. All patients had progressive tumors, progressive symptoms, or both. Mean tumor diameter was 2.3 cm (range 0.8-3.3) on magnetic resonance (MR) scan. Dentate patients were given a dose of 5 x 4 Gy or 5 x 5 Gy and edentate patients were given a dose of 1 x 10 Gy or 1 x 12.50 Gy prescribed to the 80% isodose. All patients were treated with a single isocenter. Results: With a mean follow-up period of 25 months (range 12-61), the actuarial local control rate at 5 years was 91% (only 1 patient failed). The actuarial rate of hearing preservation at 5 years was 66% in previously-hearing patients. The actuarial rate of freedom from trigeminal nerve toxicity was 97% at 5 years. No patient developed facial nerve toxicity or other complications. Conclusion: In this unselected series, fractionated stereotactic radiation therapy and linear accelerator-based radiosurgery give excellent local control in acoustic neuroma. It combines a high rate of preservation of hearing with a very low rate of other toxicity, although follow-up is relatively short

  12. Low-Dose (10-Gy) Total Skin Electron Beam Therapy for Cutaneous T-Cell Lymphoma: An Open Clinical Study and Pooled Data Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kamstrup, Maria R., E-mail: mkam0004@bbh.regionh.dk [Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen (Denmark); Gniadecki, Robert [Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen (Denmark); Iversen, Lars [Department of Dermatology, Aarhus University Hospital, Aarhus (Denmark); Skov, Lone [Department of Dermatology, Gentofte Hospital, University of Copenhagen, Copenhagen (Denmark); Petersen, Peter Meidahl [Department of Oncology and Hematology, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Loft, Annika [Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Specht, Lena [Department of Oncology and Hematology, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark)

    2015-05-01

    Purpose: Cutaneous T-cell lymphomas (CTCLs) are dominated by mycosis fungoides (MF) and Sézary syndrome (SS), and durable disease control is a therapeutic challenge. Standard total skin electron beam therapy (TSEBT) is an effective skin-directed therapy, but the possibility of retreatments is limited to 2 to 3 courses in a lifetime due to skin toxicity. This study aimed to determine the clinical effect of low-dose TSEBT in patients with MF and SS. Methods and Materials: In an open clinical study, 21 patients with MF/SS stages IB to IV were treated with low-dose TSEBT over <2.5 weeks, receiving a total dose of 10 Gy in 10 fractions. Data from 10 of these patients were published previously but were included in the current pooled data analysis. Outcome measures were response rate, duration of response, and toxicity. Results: The overall response rate was 95% with a complete cutaneous response or a very good partial response rate (<1% skin involvement with patches or plaques) documented in 57% of the patients. Median duration of overall cutaneous response was 174 days (5.8 months; range: 60-675 days). TSEBT-related acute adverse events (grade 1 or 2) were observed in 60% of patients. Conclusions: Low-dose (10-Gy) TSEBT offers a high overall response rate and is relatively safe. With this approach, reirradiation at times of relapse or progression is likely to be less toxic than standard dose TSEBT. It remains to be established whether adjuvant and combination treatments can prolong the beneficial effects of low-dose TSEBT.

  13. The role of total dose in conservative surgery and radiation therapy for early stage breast cancer: is there a critical level?

    Energy Technology Data Exchange (ETDEWEB)

    White, Julia; Brown, Douglas; Gustafson, Greg; Chen, Peter; Matter, Richard; Cook, Carla; Martinez, Alvaro; Vicini, Frank A

    1995-07-01

    Purpose: Over the past several years, it has been our standard policy after breast conserving surgery to treat the entire breast to 45-50 Gy followed by a supplemental boost dose to the tumor bed to a minimum of 60 Gy with standard fractionation. We reviewed patients who received < 60 Gy to the tumor bed to identify any differences in recurrence rates in the breast. Materials and Methods: From 1/1/75 through 12/31/87, 443 consecutive patients diagnosed with stage I and II breast cancer (unilateral) were treated with conservative surgery and radiation therapy (CSRT) at William Beaumont Hospital. All patients underwent at least an excisional biopsy and 268 (60%) patients were re-excised. An ipsilateral axillary lymph node dissection was performed on 420 patients (95%). All patients received whole breast irradiation to 45-50 Gy. A supplemental boost dose was delivered to the tumor bed with either an implant, electrons, or photons in 404 (91%) patients. Median follow-up of surviving patients is 88 months. Results: Thirty-three patients of the 443 have suffered a failure in the treated breast for a 5 and 10 yr actuarial rate of local recurrence of 5 and 10%, respectively. Evaluation by total dose to the tumor bed is as follows: The distribution of patient's respective histology, tumor size, hormonal status, age, re-excision status, and adjuvant systemic therapy was similar among the dose groups. On multivariate analysis (Cox), in addition to total dose to tumor bed (p=0.002), the only other factor which was significantly associated with local recurrence was patient age {<=} 35 (p=0.002). Conclusions: Patients who receive {<=} 50 Gy to the tumor bed without careful attention to excisional status are at a significantly higher risk of local failure. This underlies the importance of supplementing the tumor bed dose after whole breast radiation therapy in those patients whose status of excision is not definitely known.

  14. Modification of UV-induced mutation frequencies in Chinese hamster- cells by dose fractionation, cycloheximide and caffeine treatments

    International Nuclear Information System (INIS)

    Chang, C.-C.; Schultz, R.; Trosko, J.E.; D'Ambrosio, S.M.; Setlow, R.B.

    1978-01-01

    Chinese hamster (V79) cells were irradiated with a fractionated regime of ultraviolet light (UV 1 +UV 2 ). The fractionation of a UV dose always increased the colony-forming ability but reduced (or it did not change) the mutation frequencies. Treatment with cycloheximide between the two UV irradiations resulted in two types of effects, depending on the protocols used. Long exposures to cycloheximide (i.e., >6h) for the entire period between UV 1 and UV 2 or partial treatment of cycloheximide (i.e., 3h) long before UV 2 always resulted in reduced colony-forming ability and enhanced or unchanged mutation frequencies. Exposure to cycloheximide for the entire period in the short fractionated regime (i.e., 4h) between UV 1 and UV 2 or partial treatment of cycloheximide just prior to UV 2 tended to give the opposite effects. Caffeine treatment before UV 2 , with or without UV 1 , significantly increased the mutation frequencies. These results suggest that an error-free postreplication repair system exists in Chinese hamster cells which is inhibitable by particular cycloheximide or caffeine treatments. (Auth.)

  15. Correlation Between Total Flavonoid Contents and Macrophage Phagocytosis Activity of Fractions From Faloak (Sterculia quadrifida R.Br. Barks Ethanolic Extract In Vitro

    Directory of Open Access Journals (Sweden)

    Rima Munawaroh

    2018-04-01

    Full Text Available On Timor island, Nusa Tenggara Timur, faloak barks (Sterculia quadrifida R.Br. has been used empirically to restore stamina. Faloak bark ethanolic extract proved to have immunomodulatory activity in vitro, which can increase macrophage phagocytosis activity. This research aimed: (i to determine the immunomodulatory active fraction of faloak bark ethanolic extract, (ii to determine the total flavonoid contents of faloak extract and fractions, and (iii to evaluate the correlation of the total flavonoid contents of those extract and fractions with their macrophage phagocytosis activity. The simplisia powder is macerated with 96% ethanol. The extract was dissolved in methanol:water (9:1v/v was then subsequently partitioned with n-hexane, ethyl acetate, and water to obtain n-hexane fraction, ethyl acetate fraction, water fraction, and insoluble fraction. Faloak extract and fractions at concentration 62,5; 125; 250; 500μg/mL were tested for their effect on the peritoneal macrophage phagocytosis of Balb/c mice in vitro by the latex beads method. Phagocytosis capacity and phagocytosis index were analyzed using one-way anova and post hoc Tukey HSD test with 95% confidence level. The results showed that ethyl acetate fraction had the highest macrophage phagocytosis capacity and the highest total flavonoid content compared to other fractions. The highest macrophage phagocytosis capacity of ethyl acetate fraction at concentration of 250 μg/mL was 51,94±4,67%, this value was significantly different from cell control (7,50±1,29%, negative controls of 0,0625% dimethylsulphoxide (6,25±0,36%, as well as positive control of 200 μg/mL echinaceae extract syrup® (9,97±0,33%. The total flavonoid content of ethyl acetate fraction determined by aluminum chloride method was 4,290±0.029 mg of quercetin equivalent/g fraction. There was a positive and strong correlation between the total flavonoid content of these extract and fractions with their macrophage

  16. Optimization of total arc degree for stereotactic radiotherapy by using integral biologically effective dose and irradiated volume

    International Nuclear Information System (INIS)

    Lim, Do Hoon; Kim, Dae Yong; Lee, Myung Za; Chun, Ha Chung

    2001-01-01

    To find the optimal values of total arc degree to protect the normal brain tissue from high dose radiation in stereotactic radiotherapy planning. With Xknife-3 planning system and 4 MV linear accelerator, the authors planned under various values of parameters. One isocenter, 12, 20, 30, 40, 50, and 60 mm of collimator diameters, 100 deg, 200 deg, 300 deg, 400 deg, 500 deg, 600 deg, of total arc degrees, and 30 deg or 45 deg of arc intervals were used. After the completion of planning, the plans were compared each other using V 50 (the volume of normal brain that is delivered high dose radiation) and integral biologically effective dose. At 30 deg of arc interval, the values of V 50 had the decreased pattern with the increase of total arc degree in any collimator diameter. At 45 deg arc interval, up to 400 deg of total arc degree, the values of V 50 decreased with the increase of total arc degree, but at 500 deg and 600 deg of total arc degrees, the values increased. At 30 deg of arc interval, integral biologically effective dose showed the decreased pattern with the increase of total arc degree in any collimator diameter. At 45 deg arc interval with less than 40 mm collimator diameter, the integral biologically effective dose decreased with the increase of total arc degree, but with 50 and 60 mm of collimator diameters, up to 400 deg of total arc degree, integral biologically effective dose decreased with the increase of total arc degree, but at 500 deg and 600 deg of total arc degrees, the values increased. In the stereotactic radiotherapy planning for brain lesions, planning with 400 deg of total arc degree is optimal. Especially, when the larger collimator more than 50 mm diameter should be used, the uses of 500 deg and 600 deg of total arc degrees make the increase of V 50 and integral biologically effective dose, Therefore stereotactic radiotherapy planning using 400 deg of total arc degree can increase the therapeutic ratio and produce the effective outcome

  17. SU-F-T-01: Optimization of the Accelerated Partial Breast Brachytherapy Fractionation with Consideration of Physical Doses to Tumor and Organ at Risk

    Energy Technology Data Exchange (ETDEWEB)

    Fu, W; Huq, M [University of Pittsburgh Cancer Institute Pittsburgh, PA (United States)

    2016-06-15

    Purpose: The accelerated partial breast irradiation (APBI) with brachytherapy prescribes 34Gy to be delivered in 10 fractions over 5 consecutive working days without considering the physical dose to the target and organs at risk (OARs) for an individual patient. The purpose of this study is to optimize the fractionation scheme by evaluating the radiation effect on tumor and OARs with a modified linear-quadratic (LQ) model based on dose-volume histograms (DVHs). Methods: Five breast patients treated with multilumen balloon brachytherapy were selected. The minimum skin and rib spacing were ranged from 2.5mm to 14.3mm and from 1.0mm to 25.0mm, respectively. The LQ model parameters were set as: (1) breast: α=0.08, β=0.028, doubling time Tpot=14.4 days, and starting time Tk=21days; (2) skin: acute reaction α=0.101, β=0.009; late reaction α=0.064, β=0.029; (3) rib: α=0.3, β=0.12. Boundary dose Dt was 6 Gy for both target and OARs. The relation between radiation effects on the tumor (ET) and OARs (EOAR) were plotted for fraction number from 1 to 20. Results: The value of radiation effect from routine 3.4Gyx10 fractions was used as reference, ETref and EOARref. If set ET=ETref, the fractionation that results in minimum EOAR values correspond to the optimal fractionation. For these patients, the optimal numbers are 10 fractions for skin acute reaction, 18 fractions for skin and rib late reaction while the doses per fraction are 3.4Gy and 2.05–2.10Gy, respectively. If set EOAR=EOARref, the fractionation that results in a maximum ET value corresponds to the optimal fractionation. The optimal fractionation is 3.4Gyx10 fractions for skin acute reaction, and 2.10–2.25Gyx18 fractions for skin late reaction and rib. Conclusion: For APBI brachytherapy, the routine 3.4Gyx10 fractions is optimal fractionation for skin acute reaction, while 2.05–2.25Gyx18 fractions is optimal fractionation for late reaction of skin and rib.

  18. Modification of the biologic dose to normal tissue by daily fraction

    Energy Technology Data Exchange (ETDEWEB)

    Wollin, M; Kagan, A R [Southern California Permanente Medical Group, Los Angeles Calif. (USA). Dep. of Radiation Therapy

    1976-12-01

    A method to predict normal tissue injury is proposed that includes high daily doses and unusual times successfully by calculating a new value called BIR (Biologic Index of Reaction). BIR and NSD were calculated for various normal tissue reactions. With the aid of statistical correlation techniques it is found that the BIR model is better than the NSD model in predicting radiation myelopathy and vocal edema and as good as NSD IN PREDICTING RIB FRACTURE/ Neither model predicts pericardial effusion. In no case were the results of BIR inferior to those of NSD.

  19. The role of low-dose total body irradiation in treatment of non-Hodgkin's lymphoma: a new look at an old method

    International Nuclear Information System (INIS)

    Safwat, A.

    2000-01-01

    The use of low-dose total body irradiation (LTBI) in treatment of lymphomatous malignancies dates back to the 1920s. The usual practice was to give very low individual TBI fraction sizes (0. 1-0.25 Gy) several times a week to a total dose of 1.5-2 Gy. Despite this very low total dose, LTBI could induce long term remissions and was always as effective as the chemotherapy to which it was compared. In modem radiotherapy, LTBI is still a valid option in treatment of chronic lymphocytic leukaemia (CLL) and the advanced stages of indolent low-grade non-Hodgkin's lymphoma (NHL). Its use in the early stages of low-grade NHL is under investigation in a large multi-institutional trial. The efficacy of LTBI is believed to stem from three mechanisms, namely; immune-enhancement, induction of apoptosis, and the intrinsic hypersensitivity to low-radiation doses demonstrated in many cell lines and tumour systems. Thus, LTBI seems to provide 'alternative' mechanisms of action against cancer cells. This should encourage researchers to explore strategies that integrate LTBI in new and innovative experimental treatment protocols that explore the possible synergism between LTBI and chemotherapy, biological response modifiers and/or immunotherapy. The increased incidence of secondary leukaemia that occurs when LTBI is combined with alkylating agents and/or total lymphoid irradiation should be kept in mind when designing such protocols as it may limit the use of LTBI in highly curable diseases and young patients in whom long survival is expected. (author)

  20. The influence of single and fractionated dose external beam irradiation on injury-induced arterial smooth muscle cell proliferation

    International Nuclear Information System (INIS)

    Schaefer, U.; Micke, O.; Dorszewski, A.; Breithardt, G.; Willich, N.

    1997-01-01

    Purpose/Objective: Restenosis after catheter-based revascularization has been demonstrated to be primarily caused by smooth muscle cell proliferation. This study examined the effects of external beam irradiation on neointimal proliferation after external injury to the central artery of the rabbit ear. Materials and Methods: 40 male New Zealand White rabbits were used in this study. Crush lesions were performed on each ear under general anesthesia and bilateral auricular nerve blockade. A single dose of 12 Gy (n=10), 16 Gy (n=10), or 20 Gy (n=10) and a fractionated dose of 4 x 5 Gy (n=10) gamma radiation was delivered to the left or right central artery of the ear 24 hours after injury; the contralateral central artery served as control. All rabbits were sacrificed after twenty-one days and the central arteries of the ear were fixed for morphometric measurements. Results: Mean (± SD) neointimal area was 0.062 ± 0.005 mm 2 (12 Gy), 0.022 ± 0,005 mm 2 (16 Gy), 0,028 ± 0,006 mm 2 and 0.038 mm 2 ± 0,02 mm 2 (4 x 5 Gy) in irradiated arteries compared with 0,081 ± 0,009 mm 2 in the control group. Mean (±SD) luminal area was 0.049 ± 0.004 mm 2 (12 Gy), 0.059 ± 0.002 mm 2 (16 Gy), 0.072 ± 0,006 mm 2 (20 Gy) and 0.048 mm 2 ± 0,018 mm 2 (4 x 5 Gy) in irradiated arteries compared with 0,043 ± 0,008 mm 2 in the control group. The difference in neointimal and luminal area between control and irradiated arteries was significant (p<0.05) only for the 16 and 20 Gy group compared to control. Conclusion: We conclude that in this model, external beam X-ray irradiation was successful in reducing neointimal proliferation after injury of the central artery of the rabbit ear. The optimal dose seems to be a single dose of 16 Gy - 20 Gy. Only a less prominent effect was noted for a fractionated dose of 4 x 5 Gy. Whether this approach can be used successfully to inhibit restenosis in the clinical setting requires further investigation

  1. High-Dose, Single-Fraction Irradiation Rapidly Reduces Tumor Vasculature and Perfusion in a Xenograft Model of Neuroblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Jani, Ashish; Shaikh, Fauzia; Barton, Sunjay [Department of Radiation Oncology, Columbia University Medical Center, New York, New York (United States); Willis, Callen [Department of Surgery, Columbia University Medical Center, New York, New York (United States); Banerjee, Debarshi [Department of Pediatrics, Columbia University Medical Center, New York, New York (United States); Mitchell, Jason [Department of Surgery, Columbia University Medical Center, New York, New York (United States); Hernandez, Sonia L. [Department of Surgery, University of Chicago, Chicago, Illinois (United States); Hei, Tom [Department of Radiation Oncology, Columbia University Medical Center, New York, New York (United States); Kadenhe-Chiweshe, Angela [Department of Surgery, Columbia University Medical Center, New York, New York (United States); Yamashiro, Darrell J. [Department of Surgery, Columbia University Medical Center, New York, New York (United States); Department of Pediatrics, Columbia University Medical Center, New York, New York (United States); Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York (United States); Connolly, Eileen P., E-mail: epc2116@cumc.columbia.edu [Department of Radiation Oncology, Columbia University Medical Center, New York, New York (United States)

    2016-04-01

    Purpose: To characterize the effects of high-dose radiation therapy (HDRT) on neuroblastoma tumor vasculature, including the endothelial cell (EC)–pericyte interaction as a potential target for combined treatment with antiangiogenic agents. Methods and Materials: The vascular effects of radiation therapy were examined in a xenograft model of high-risk neuroblastoma. In vivo 3-dimensional contrast-enhanced ultrasonography (3D-CEUS) imaging and immunohistochemistry (IHC) were performed. Results: HDRT significantly reduced tumor blood volume 6 hours after irradiation compared with the lower doses used in conventionally fractionated radiation. There was a 63% decrease in tumor blood volume after 12-Gy radiation compared with a 24% decrease after 2 Gy. Analysis of tumor vasculature by lectin angiography showed a significant loss of small vessel ends at 6 hours. IHC revealed a significant loss of ECs at 6 and 72 hours after HDRT, with an accompanying loss of immature and mature pericytes at 72 hours. Conclusions: HDRT affects tumor vasculature in a manner not observed at lower doses. The main observation was an early reduction in tumor perfusion resulting from a reduction of small vessel ends with a corresponding loss of endothelial cells and pericytes.

  2. Clinical evaluation of the hypoxic cytotoxin tirapazamine (SR-4233): phase I experience with repeated dose administration during fractionated irradiation

    International Nuclear Information System (INIS)

    Hancock, Steven L.; Spencer, Sharon; Mariscal, Carol; Wooten, Ann; Wheeler, Richard; Brown, J. Martin; Fisher, Cheryl; Roemeling, Reinhard von

    1996-01-01

    Purpose: Regions of chronic or transient hypoxia are common in many human tumors and are thought to limit tumor cell killing and tumor control with conventional irradiation and some chemotherapeutic agents. Tirapazamine (3-amino-1,2,4-benzotriazine-1,4-di-N-oxide) forms a cytotoxic free radical during reductive metabolism in regions of hypoxia. In well oxygenated regions, the tirapazamine radical reacts with molecular oxygen to form the inactive parent drug. This results in markedly greater toxicity for hypoxic cells than for the well oxygenated cells that comprise most normal tissues. Tirapazamine increased the anti-tumor effects of single dose or fractionated irradiation or cis-platin chemotherapy in murine tumors,in vivo . This study evaluated the ability to repeat the administration of Tirapazamine during courses of fractionated irradiation in humans after an earlier phase I trial established a maximum tolerated dose of 390 mg per square meter of body surface area (mg/m 2 ) when given as a single dose with radiotherapy. Materials and Methods: Between December 1993 and August 1995 22 patients with locally advanced or metastatic tumors of varying histology, normal renal, hepatic, and hematologic functions, and Karnofsky performance status ≥ 60 received repeated doses of Tirapazamine during a planned, 6 weeks course of standardly fractionated radiotherapy. After anti-emetic treatment with ondansetron (32 mg) and dexamethasone (16 mg), Tirapazamine was administered during a 2 hour intravenous infusion that ended from 30 to 90 minutes before a radiation treatment. Patients were monitored for acute toxicity during the course of treatment and for a minimum of one month after radiotherapy. Results: The study was initiated with three, biweekly doses of Tirapazamine at 330 mg/m 2 . Four of 7 patients who initiated treatment at this dose refused the second (1 patient) or third dose of Tirapazamine (3 patients). Two of the three patients who received three doses

  3. Analysis of bias effects on the total ionizing dose response in a 180 nm technology

    International Nuclear Information System (INIS)

    Liu Zhangli; Hu Zhiyuan; Zhang, Zhengxuan; Shao Hua; Chen Ming; Bi Dawei; Ning Bingxu; Zou Shichang

    2011-01-01

    The effects of gamma ray irradiation on the shallow trench isolation (STI) leakage current in a 180 nm technology are investigated. The radiation response is strongly influenced by the bias modes, gate bias during irradiation, substrate bias during irradiation and operating substrate bias after irradiation. We found that the worst case occurs under the ON bias condition for the ON, OFF and PASS bias mode. A positive gate bias during irradiation significantly enhances the STI leakage current, indicating the electric field influence on the charge buildup process during radiation. Also, a negative substrate bias during irradiation enhances the STI leakage current. However a negative operating substrate bias effectively suppresses the STI leakage current, and can be used to eliminate the leakage current produced by the charge trapped in the deep STI oxide. Appropriate substrate bias should be introduced to alleviate the total ionizing dose (TID) response, and lead to acceptable threshold voltage shift and subthreshold hump effect. Depending on the simulation results, we believe that the electric field distribution in the STI oxide is the key parameter influencing bias effects on the radiation response of transistor. - Highlights: → ON bias is the worst bias condition for the ON, PASS and OFF bias modes. → Larger gate bias during irradiation leads to more pronounced characteristic degradation. → TID induced STI leakage can be suppressed by negative operating substrate bias voltage. → Negative substrate bias during irradiation leads to larger increase of off-state leakage. → Electric field in the STI oxide greatly influences the device's radiation effect.

  4. Evaluation of Total Daily Dose and Glycemic Control for Patients on U-500 Insulin Admitted to the Hospital

    Science.gov (United States)

    2016-05-20

    regular insulin has significantly increased in recent years. These patients are severely insulin resistant requiring high doses of insulin to achieve...on U-500 Insulin Admitted to the Hospital presented at SURF Conference, San Antonio, TX 20 May 201 6 with MDWI 41-108, and has been assigned local...59th CSPG/SGVU) C.201 4 . I 52d PROTOCOL TITLE Evaluation of Total Dai ly Dose and Glycemic Control for Patients on U-500 Insulin Admitted to the

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-07

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

  7. Clinical responses after total body irradiation by over permissible dose of γ-rays in one time

    International Nuclear Information System (INIS)

    Jiang Benrong; Wang Guilin; Liu Huilan; Tang Xingsheng; Ai Huisheng

    1990-01-01

    The clinical responses of patients after total body over permissilbe dose γ-ray irradiation were observed and analysed. The results showed: when the dose was above 5 cGy, there was some immunological depression, but no significant change in hematopoietic functions. 5 cases showed some transient changes of ECG, perhaps due to vagotonia caused by psychological imbalance, One case vomitted 3-4 times after 28 cGy irradiation, this suggested that a few times of vomitting had no significance in the estimation of the irradiated dose and the whole clinical manifestations must be concretely analysed

  8. Fast method for in-flight estimation of total dose from protons and electrons using RADE Minstrument on JUICE

    Science.gov (United States)

    Hajdas, Wojtek; Mrigakshi, Alankrita; Xiao, Hualin

    2017-04-01

    The primary concern of the ESA JUICE mission to Jupiter is the harsh particle radiation environment. Ionizing particles introduce radiation damage by total dose effects, displacement damages or single events effects. Therefore, both the total ionizing dose and the displacement damage equivalent fluence must be assessed to alert spacecraft and its payload as well as to quantify radiation levels for the entire mission lifetime. We present a concept and implementations steps for simplified method used to compute in flight a dose rate and total dose caused by protons. We also provide refinement of the method previously developed for electrons. The dose rates values are given for predefined active volumes located behind layers of materials with known thickness. Both methods are based on the electron and proton flux measurements provided by the Electron and Proton Detectors inside the Radiation Hard Electron Monitor (RADEM) located on-board of JUICE. The trade-off between method accuracy and programming limitations for in-flight computations are discussed. More comprehensive and precise dose rate computations based on detailed analysis of all stack detectors will be made during off-line data processing. It will utilize full spectral unfolding from all RADEM detector subsystems.

  9. Three-dimensional Finite Elements Method simulation of Total Ionizing Dose in 22 nm bulk nFinFETs

    Energy Technology Data Exchange (ETDEWEB)

    Chatzikyriakou, Eleni, E-mail: ec3g12@soton.ac.uk; Potter, Kenneth; Redman-White, William; De Groot, C.H.

    2017-02-15

    Highlights: • Simulation of Total Ionizing Dose using the Finite Elements Method. • Carrier generation, transport and trapping in the oxide. • Application in three-dimensional bulk FinFET model of 22 nm node. • Examination of trapped charge in the Shallow Trench Isolation. • Trapped charge dependency of parasitic transistor current. - Abstract: Finite Elements Method simulation of Total Ionizing Dose effects on 22 nm bulk Fin Field Effect Transistor (FinFET) devices using the commercial software Synopsys Sentaurus TCAD is presented. The simulation parameters are extracted by calibrating the charge trapping model to experimental results on 400 nm SiO{sub 2} capacitors irradiated under zero bias. The FinFET device characteristics are calibrated to the Intel 22 nm bulk technology. Irradiation simulations of the transistor performed with all terminals unbiased reveal increased hardness up to a total dose of 1 MRad(SiO{sub 2}).

  10. Comparison of patient-reported acute urinary and sexual toxicity scores in a 6- versus 2-fraction course of high-dose-rate prostate brachytherapy monotherapy

    International Nuclear Information System (INIS)

    Ragab, Omar; Park, Sang-June; Zhang, Mingle; Wang, Jason; Velez, Maria; Demanes, David J.; Banerjee, Robyn; Patel, Shyamal; Kamrave, Mitchell

    2018-01-01

    To identify differences in acute urinary and sexual toxicity between a 6-fraction and 2-fraction high-dose-rate brachytherapy monotherapy regimen and correlate dosimetric constraints to short-term toxicity. A single institution retrospective study of 116 men with prostate cancer treated with HDR monotherapy from 2010 to 2015 was conducted. Eighty-one men had 7.25 Gy × 6-fractions and 35 men had 13.5 Gy × 2-fractions. Patients had two CT-planned implants spaced 1–2 weeks apart. Patient baseline characteristics, International Prostate Symptom Scores (IPSS) and Sexual Health Inventory for Men (SHIM) scores were collected pre-treatment and 3, 6 and 12 months post-implantation. Mixed effect modelling was undertaken to compare baseline, 1–6 month and 7–12 month scores between groups. Poisson regression analysis was performed to correlate dosimetric constraints with acute toxicity. There was no difference between baseline and post-implantation IPSS scores between 6-fraction and 2-fraction groups. SHIM scores for men treated with 6-fractions had a steeper decline at 1–6 months, but resolved at 7–12 months. Pre-treatment alpha-blocker use correlated with worse short-term acute urinary toxicity. Worsened SHIM score correlated with increasing age, diabetes mellitus and androgen-deprivation therapy. In a dosimetric analysis of outcomes, prostate V150 dose and bladder wall (D01.cc, D1cc, D2cc) dose correlated with increased IPSS score. No increased acute genitourinary or sexual dysfunction has been observed in men when transitioning from 6-fraction to 2-fraction HDR monotherapy. A dosimetric correlation was found between the V150 and bladder wall doses for acute urinary toxicity. Future research should continue to standardize and validate dose constraints for prostate HDR monotherapy patients.

  11. Dose rate and total dose dependence of the 1/f noise performance of a GaAs operational amplifier during irradiation

    International Nuclear Information System (INIS)

    Hiemstra, D.M.

    1995-01-01

    A pictorial of a sectioned view of the torus of the International Thermonuclear Experimental Reactor (ITER) is shown. Maintenance and inspection of the reactor are required to be performed remotely. This is due to the high gamma radiation environment in vessel during inspection and maintenance activities. The custom GaAs operational amplifier is to be used to readout sensors on the in-vessel manipulator and inspection equipment. The gamma dose rate during maintenance and inspection is anticipated to be 3 Mrad(GaAs)/hour. Here, dose rate and total dose dependence of the 1/f noise performance of a custom GaAs MESFET operational amplifier during irradiation are presented. Dose rate dependent 1/f noise degradation during irradiation is believed to be due to electron trapping in deep levels, enhanced by backgating and shallow traps excited during irradiation. The reduction of this affect with accumulated total dose is believed to be due a reduction of deep level site concentration associated with substitutional oxygen. Post irradiation 1/f noise degradation is also presented.The generation-recombination noise observed post irradiation can be attributed to the production of shallow traps due to ionizing radiation

  12. Central axis dose verification in patients treated with total body irradiation of photons using a Computed Radiography system

    International Nuclear Information System (INIS)

    Rubio Rivero, A.; Caballero Pinelo, R.; Gonzalez Perez, Y.

    2015-01-01

    To propose and evaluate a method for the central axis dose verification in patients treated with total body irradiation (TBI) of photons using images obtained through a Computed Radiography (CR) system. It was used the Computed Radiog