Methods of bone marrow dose calculation
International Nuclear Information System (INIS)
Taboaco, R.C.
1982-02-01
Several methods of bone marrow dose calculation for photon irradiation were analised. After a critical analysis, the author proposes the adoption, by the Instituto de Radioprotecao e Dosimetria/CNEN, of Rosenstein's method for dose calculations in Radiodiagnostic examinations and Kramer's method in case of occupational irradiation. It was verified by Eckerman and Simpson that for monoenergetic gamma emitters uniformly distributed within the bone mineral of the skeleton the dose in the bone surface can be several times higher than dose in skeleton. In this way, is also proposed the Calculation of tissue-air ratios for bone surfaces in some irradiation geometries and photon energies to be included in the Rosenstein's method for organ dose calculation in Radiodiagnostic examinations. (Author) [pt
International Nuclear Information System (INIS)
Stabin, Michael G.
2004-01-01
Nuclear medicine therapy is being used increasingly in the treatment of cancer (thyroid, leukemia/lymphoma with RIT, primary and secondary bone malignancies, and neuroblastomas). In all cases it is marrow toxicity that limits the amount of treatment that can be administered safely. Marrow dose calculations are more difficult than for many major organs because of the intricate association of bone and soft tissue elements. In RIT, there appears to be no consensus on how to calculate that dose accurately, or of individual patients ability to tolerate planned therapy. Available dose models are designed after an idealized average, healthy individual. Patient-specific methods are applied in evaluation of biokinetic data, and need to be developed for treatment of the physical data (dose conversion factors) as well: age, prior patient therapy, disease status. Contributors to marrow dose: electrons and photons
System for estimation of mean active bone marrow dose
International Nuclear Information System (INIS)
Ellis, R.E.; Healy, M.J.R.; Shleien, B.; Tucker, T.
1975-09-01
The exposure measurements, model and computer program for estimation of mean active bone marrow doses formerly employed in the 1962 British Survey of x-ray doses and proposed for application to x-ray exposure information obtained in the U.S. Public Health Service's X-Ray Exposure Studies (1966 and 1973) are described and evaluated. The method described is feasible for use to determine the mean active bone marrow doses to adults for examinations having a skin to source distance of 80 cm or less. For a greater SSD, as for example in chest x rays, a small correction in the calculation dose can be made
Absorbed dose to active red bone marrow from diagnostic and therapeutic uses of radiation
International Nuclear Information System (INIS)
Solomon, S.B.
1980-06-01
The bone-marrow dose arising from radiological procedures as carried out in Australia have been determined as part of a survey of population doses. This paper describes the method of calculation of the radiation doses to the active bone marrow from diagnostic radiography, fluoroscopy and radiotherapy. The results of the calculations are compared with the results of other models of bone-marrow dose for a number of diagnostic X-ray procedures
Radioactive cloud dose calculations
International Nuclear Information System (INIS)
Healy, J.W.
1984-01-01
Radiological dosage principles, as well as methods for calculating external and internal dose rates, following dispersion and deposition of radioactive materials in the atmosphere are described. Emphasis has been placed on analytical solutions that are appropriate for hand calculations. In addition, the methods for calculating dose rates from ingestion are discussed. A brief description of several computer programs are included for information on radionuclides. There has been no attempt to be comprehensive, and only a sampling of programs has been selected to illustrate the variety available
Dose calculation for electrons
International Nuclear Information System (INIS)
Hirayama, Hideo
1995-01-01
The joint working group of ICRP/ICRU is advancing the works of reviewing the ICRP publication 51 by investigating the data related to radiation protection. In order to introduce the 1990 recommendation, it has been demanded to carry out calculation for neutrons, photons and electrons. As for electrons, EURADOS WG4 (Numerical Dosimetry) rearranged the data to be calculated at the meeting held in PTB Braunschweig in June, 1992, and the question and request were presented by Dr. J.L. Chartier, the responsible person, to the researchers who are likely to undertake electron transport Monte Carlo calculation. The author also has carried out the requested calculation as it was the good chance to do the mutual comparison among various computation codes regarding electron transport calculation. The content that the WG requested to calculate was the absorbed dose at depth d mm when parallel electron beam enters at angle α into flat plate phantoms of PMMA, water and ICRU4-element tissue, which were placed in vacuum. The calculation was carried out by the versatile electron-photon shower computation Monte Carlo code, EGS4. As the results, depth dose curves and the dependence of absorbed dose on electron energy, incident angle and material are reported. The subjects to be investigated are pointed out. (K.I.)
Weldon Spring dose calculations
International Nuclear Information System (INIS)
Dickson, H.W.; Hill, G.S.; Perdue, P.T.
1978-09-01
In response to a request by the Oak Ridge Operations (ORO) Office of the Department of Energy (DOE) for assistance to the Department of the Army (DA) on the decommissioning of the Weldon Spring Chemical Plant, the Health and Safety Research Division of the Oak Ridge National Laboratory (ORNL) performed limited dose assessment calculations for that site. Based upon radiological measurements from a number of soil samples analyzed by ORNL and from previously acquired radiological data for the Weldon Spring site, source terms were derived to calculate radiation doses for three specific site scenarios. These three hypothetical scenarios are: a wildlife refuge for hunting, fishing, and general outdoor recreation; a school with 40 hr per week occupancy by students and a custodian; and a truck farm producing fruits, vegetables, meat, and dairy products which may be consumed on site. Radiation doses are reported for each of these scenarios both for measured uranium daughter equilibrium ratios and for assumed secular equilibrium. Doses are lower for the nonequilibrium case
Bone marrow adsorbed dose of rhenium-186-HEDP and the relationship with decreased platelet counts
International Nuclear Information System (INIS)
Klerk, J.M.H. de; Dieren, E.B. van; Schip, A.D. van het
1996-01-01
Rhenium-186(Sn)-1,1-hydroxyethylidene diphosphonate ( 186 Re-HEDP) has been used for palliation of metastatic bone pain. The purpose of this study was to find a relationship between the bone marrow absorbed dose and the toxicity, expressed as the percentage decrease in the peripheral blood platelet count. The bone marrow absorbed dose was calculated according to the MIRD model using data obtained from ten treatments of patients suffering from metastatic prostate cancer; noninvasive and pharmacokinetic method were used. The bone marrow doses were related to toxicity using the pharmacodynamic sigmoid E max model. The mean bone marrow absorbed doses using the noninvasive and pharmacokinetic methods were in a close range to each other (1.07 mGy/MBq and 1.02 mGy/MBq, respectively). There was a good relationship between the toxicity and the bone marrow absorbed dose (r = 0.80). Furthermore, the EDrm 50 (i.e., the bone marrow absorbed dose producing a 50% platelet decrease) to bone marrow for 186 Re-HEDP was on the order of 2 Gy. Although the function of normal bone marrow is affected by metastases in patients with metastatic bone disease, the MIRD model can be used to relate toxicity to the bone marrow absorbed dose after a therapeutic dosage of 186 Re-HEDP. 33 refs., 1 fig., 1 tab
The measurement of gonadal and bone-marrow doses from dental radiography
International Nuclear Information System (INIS)
Solomon, S.B.; Morris, N.D.
1980-06-01
The method of calculation of the radiation doses to the gonads and to the active bone marrow arising from dental radiography is described. The bone-marrow doses have been calculated using a computer model of X-ray depth doses within the skull for typical dental radiographic examinations as performed in Australia. The ovarian and testicular doses, as a percentage of skin dose have been determined experimentally. The dependence of the gonadal doses on X-ray tube voltage, face to cone distance and direction of the X-ray beam relative to the face is detailed
Retrospective Reconstructions of Active Bone Marrow Dose-Volume Histograms
International Nuclear Information System (INIS)
Veres, Cristina; Allodji, Rodrigue S.; Llanas, Damien; Vu Bezin, Jérémi; Chavaudra, Jean; Mège, Jean Pierre; Lefkopoulos, Dimitri; Quiniou, Eric; Deutsh, Eric; Vathaire, Florent de; Diallo, Ibrahima
2014-01-01
Purpose: To present a method for calculating dose-volume histograms (DVH's) to the active bone marrow (ABM) of patients who had undergone radiation therapy (RT) and subsequently developed leukemia. Methods and Materials: The study focuses on 15 patients treated between 1961 and 1996. Whole-body RT planning computed tomographic (CT) data were not available. We therefore generated representative whole-body CTs similar to patient anatomy. In addition, we developed a method enabling us to obtain information on the density distribution of ABM all over the skeleton. Dose could then be calculated in a series of points distributed all over the skeleton in such a way that their local density reflected age-specific data for ABM distribution. Dose to particular regions and dose-volume histograms of the entire ABM were estimated for all patients. Results: Depending on patient age, the total number of dose calculation points generated ranged from 1,190,970 to 4,108,524. The average dose to ABM ranged from 0.3 to 16.4 Gy. Dose-volume histograms analysis showed that the median doses (D 50% ) ranged from 0.06 to 12.8 Gy. We also evaluated the inhomogeneity of individual patient ABM dose distribution according to clinical situation. It was evident that the coefficient of variation of the dose for the whole ABM ranged from 1.0 to 5.7, which means that the standard deviation could be more than 5 times higher than the mean. Conclusions: For patients with available long-term follow-up data, our method provides reconstruction of dose-volume data comparable to detailed dose calculations, which have become standard in modern CT-based 3-dimensional RT planning. Our strategy of using dose-volume histograms offers new perspectives to retrospective epidemiological studies
Energy Technology Data Exchange (ETDEWEB)
Hashizume, T; Maruyama, T; Kumamoto, Y [National Inst. of Radiological Sciences, Chiba (Japan)
1976-03-01
The mean per capita marrow dose and leukemia-significant dose from radiographic and fluoroscopic examinations in Japan have been estimated based on a 1974 nation wide survey of randomly sampled hospitals and clinics. To determine the mean marrow dose to an individual from a certain exposure of a given type of examination, the active marrow in the whole body was divided into 119 parts for an adult and 103 for a child. Dosimetric points on which the individual marrow doses were determined were set up in the center of each marrow part. The individual marrow doses at the dosimetric points in the beams of practical diagnostic x-rays were calculated on the basis of the exposure data on the patients selected in the nation wide survey, using depth dose curves experimentally determined for diagnostic x-rays. The mean individual marrow dose was averaged over the active marrow by summing, for each dosimetric point, the product of the fraction of active marrow exposed and the individual marrow dose at the dosimetric point. The leukemia significant dose was calculated by adopting a weighting factor that is, a leukemia significant factor. The factor was determined from the shape of the time-incidence curve for radiation-induced leukemia from the Hiroshima A-bomb and from the survival statistics for the average population. The resultant mean per capita marrow dose from radiographic and fluoroscopic examination was 37.0 and 70.0 mrad/person/year, respectively, with a total of 107.05 mrad/person/year. The leukemia significant dose was 32.1 mrad/person/year for radiographic examination and 61.2 mrad/person/year, with a total of 93.3. These values were compared with those of 1960 and 1969.
Survey of gonad and bone marrow doses from IUCD fluoroscopy in women of Guangdong province
International Nuclear Information System (INIS)
Zeng Xishen; Fan Jincai
1984-01-01
The local exposure doses in fluoroscopy for intrauterine contraceptive device (IUCD) were surveyed with TLD in 150 women. The gonad and bone marrow doses were calculated by adopting both the results of radiation experiment on MIXD phantom and related data. The mean gonad and bone marrow doses are 13.6 and 18.7 mrad, respectively. The collective bone marrow dose equivalent was estimated from the numbers of women fitted with IUCD and of women undergoing fluoroscopy, and the census of women of child-bearing age in Guangdong Province. The significance of collective bone marrow dose equivalent by IUCD fluoroscopy is discussed on the basis of the risk estimate of leukemia in ICRP publication No 26. (author)
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
Absorbed bone marrow dose in certain dental radiographic techniques
International Nuclear Information System (INIS)
White, S.C.; Rose, T.C.
1979-01-01
The absorbed dose of radiation in the bone marrow of the region of the head and neck was measured during intraoral, panoramic, and cephalometric radiography. Panoramic radiography results in a dose a fifth or less than that from an intraoral survey. The use of rectangular collimation reduces the bone marrow absorbed dose from an intraoral survey by about 60%. Comparison of the doses from dental radiography with natural environmental radiation shows that an intraoral set of films results in the same total dose to the bone marrow as 65 days of background exposure. The use of rectangular collimation reduces this value to 25 days. Panoramic radiography results in significantly less irradiation, as it reduces the value to 14 days or fewer. Dental radiography thus involves exposures in the range of variation of natural environmental background values
Calculating radiation exposure and dose
International Nuclear Information System (INIS)
Hondros, J.
1987-01-01
This paper discusses the methods and procedures used to calculate the radiation exposures and radiation doses to designated employees of the Olympic Dam Project. Each of the three major exposure pathways are examined. These are: gamma irradiation, radon daughter inhalation and radioactive dust inhalation. A further section presents ICRP methodology for combining individual pathway exposures to give a total dose figure. Computer programs used for calculations and data storage are also presented briefly
Relationship of bone marrow dose to eosinophilia following radiotherapy
International Nuclear Information System (INIS)
Murohashi, Ikuo; Gomi, Hiromichi; Nakano, Takashi; Morita, Shinroku; Arai, Tatsuo; Jinnai, Itsuro; Nara, Nobuo; Bessho, Masami; Hirashima, Kunitake.
1986-01-01
Absolute blood eosinophils were counted prior to and during radiotherapy in a total of 380 patients with carcinoma in the chest, pelvis, or abdomen. The patients were divided into 5 groups by types of cancer, and these groups differed in the irradiation sites or the sizes of radiation field. Accumulated bone marrow dose from the start of radiotherapy to the time when eosinophil count during radiotherapy reached its peak was simultaneously determined. In each group, maximum eosinophil count during radiotherapy was significantly increased compared with the value before radiotherapy. In all groups except one, the increase in eosinophil count following radiotherapy was directly proportional to the bone marrow dose. However, in the most heavily irradiated ovarian cancer group, the increase in eosinophil count was markedly lower. In contrast, neutrophils were reduced in numbers in all groups. These results suggest that bone marrow (red marrow) damage by irradiation results in eosinophilia, and that unimpaired hemopoiesis is also indispensable for such an eosinophil response. Accumulated bone marrow doses of 800 - 900 rad given during 4 weeks fractionated irradiation caused the most prominent eosinophilia. (author)
Prenatal radiation exposure. Dose calculation
International Nuclear Information System (INIS)
Scharwaechter, C.; Schwartz, C.A.; Haage, P.; Roeser, A.
2015-01-01
The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero X-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties.
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)
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.
International Nuclear Information System (INIS)
Shleien, B.; Tucker, T.T.; Johnson, D.W.
1977-01-01
Estimates, based on an empirical model and computer program, have been calculated and are presented on the mean active bone marrow dose to adults from diagnostic radiography, fluoroscopy, and dental radiography as practiced in the United States in 1970. The annual per capita mean active bone marrow dose in 1970 to adults from the above practices is estimated to be 103 mrad; 77 percent, 20 percent, and 3 percent from radiographic, fluoroscopic and dental examinations respectively. Examinations of the upper and lower abdomen contribute approximately 39 percent each to the total mean active bone marrow dose for adults; those of the pelvis 4 percent; the thorax 12 percent; and head and neck examinations (including dental) contribute about 6 percent. The per capita mean active bone marrow dose for various age groups is discussed. Contributions to the dose within a given age group from different examinations indicate that in the 15-34 year old age group Lumbar and Lumbosacral Spine examinations contribute most to the mean active bone marrow dose. Thereafter Upper G I Series and Barium Enemas are the highest contributors. Comparisons are made with results of the 1964 U.S. X-ray survey and similar surveys from other nations
Calculational Tool for Skin Contamination Dose Assessment
Hill, R L
2002-01-01
Spreadsheet calculational tool was developed to automate the calculations preformed for dose assessment of skin contamination. This document reports on the design and testing of the spreadsheet calculational tool.
International Nuclear Information System (INIS)
Gershkevitsh, E.; Trott, K.R.
2002-01-01
Purpose: Radiotherapy plays an important role in the management of prostate cancer. Epidemiological data indicate a small but significant risk of radiation-induced leukemia after radiotherapy which might be related to the high mean bone marrow dose associated with radiotherapy of prostate cancer. The purpose of the study was to investigate the relation between the mean bone marrow dose and unstable chromosome aberrations in peripheral blood lymphocytes in patients undergoing conformal radiotherapy for prostate cancer as a possible indicator of risk. Endometrial cancer patients were also included for comparison. Patients and Methods: Nine patients, six with prostate cancer (60-73 years old) and three with endometrial cancer (61-81 years old) treated with radiotherapy were included in the study. The non-bony spaces inside the pelvic bones were outlined on every CT slice using the treatment planning system and mean doses to the bone marrow calculated. Blood samples of the patients were obtained at different times before, during and at the end of treatment. Lymphocytes were cultured in the usual way and metaphases scored for dicentric aberrations. Results: 46 samples from nine patients were obtained. The mean number of metaphases analyzed per sample was 180 with a range from 52 to 435. The mean bone marrow doses for prostate cancer patients ranged from 2.8 to 4.2 Gy and for endometrial cancer patients from 12.8 to 14.8 Gy. The aberration yield increased with the planning target volume and the mean bone marrow dose. Conclusion: The yield of dicentric aberrations for prostate cancer patients correlated closely with the mean bone marrow dose albeit the induction of dicentrics occurred in mature T lymphocytes most of which were probably in transit through the irradiated volumes. Therefore, the observed relationship between dicentrics and mean bone marrow doses are indirect. (orig.) [de
Calculation methods for determining dose equivalent
International Nuclear Information System (INIS)
Endres, G.W.R.; Tanner, J.E.; Scherpelz, R.I.; Hadlock, D.E.
1987-11-01
A series of calculations of neutron fluence as a function of energy in an anthropomorphic phantom was performed to develop a system for determining effective dose equivalent for external radiation sources. Critical organ dose equivalents are calculated and effective dose equivalents are determined using ICRP-26 [1] methods. Quality factors based on both present definitions and ICRP-40 definitions are used in the analysis. The results of these calculations are presented and discussed. The effective dose equivalent determined using ICRP-26 methods is significantly smaller than the dose equivalent determined by traditional methods. No existing personnel dosimeter or health physics instrument can determine effective dose equivalent. At the present time, the conversion of dosimeter response to dose equivalent is based on calculations for maximal or ''cap'' values using homogeneous spherical or cylindrical phantoms. The evaluated dose equivalent is, therefore, a poor approximation of the effective dose equivalent as defined by ICRP Publication 26. 3 refs., 2 figs., 1 tab
Tank Z-361 dose rate calculations
International Nuclear Information System (INIS)
Richard, R.F.
1998-01-01
Neutron and gamma ray dose rates were calculated above and around the 6-inch riser of tank Z-361 located at the Plutonium Finishing Plant. Dose rates were also determined off of one side of the tank. The largest dose rate 0.029 mrem/h was a gamma ray dose and occurred 76.2 cm (30 in.) directly above the open riser. All other dose rates were negligible. The ANSI/ANS 1991 flux to dose conversion factor for neutrons and photons were used in this analysis. Dose rates are reported in units of mrem/h with the calculated uncertainty shown within the parentheses
Simplified dose calculation method for mantle technique
International Nuclear Information System (INIS)
Scaff, L.A.M.
1984-01-01
A simplified dose calculation method for mantle technique is described. In the routine treatment of lymphom as using this technique, the daily doses at the midpoints at five anatomical regions are different because the thicknesses are not equal. (Author) [pt
Calculation methods for determining dose equivalent
International Nuclear Information System (INIS)
Endres, G.W.R.; Tanner, J.E.; Scherpelz, R.I.; Hadlock, D.E.
1988-01-01
A series of calculations of neutron fluence as a function of energy in an anthropomorphic phantom was performed to develop a system for determining effective dose equivalent for external radiation sources. critical organ dose equivalents are calculated and effective dose equivalents are determined using ICRP-26 methods. Quality factors based on both present definitions and ICRP-40 definitions are used in the analysis. The results of these calculations are presented and discussed
International Nuclear Information System (INIS)
Cheng, Jonathan C.; Schultheiss, Timothy E.; Wong, Jeffrey Y.C.
2008-01-01
Purpose: To demonstrate a radiation dose response and to determine the dosimetric and chemotherapeutic factors that influence the incidence of late renal toxicity following total body irradiation (TBI). Methods and Materials: A comprehensive retrospective review was performed of articles reporting late renal toxicity, along with renal dose, fractionation, dose rate, chemotherapy regimens, and potential nephrotoxic agents. In the final analysis, 12 articles (n = 1,108 patients), consisting of 24 distinct TBI/chemotherapy conditioning regimens were included. Regimens were divided into three subgroups: adults (age ≥18 years), children (age <18 years), and mixed population (both adults and children). Multivariate logistic regression was performed to identify dosimetric and chemotherapeutic factors significantly associated with late renal complications. Results: Individual analysis was performed on each population subgroup. For the purely adult population, the only significant variable was total dose. For the mixed population, the significant variables included total dose, dose rate, and the use of fludarabine. For the pediatric population, only the use of cyclosporin or teniposide was significant; no dose response was noted. A logistic model was generated with the exclusion of the pediatric population because of its lack of dose response. This model yielded the following significant variables: total dose, dose rate, and number of fractions. Conclusion: A dose response for renal damage after TBI was identified. Fractionation and low dose rates are factors to consider when delivering TBI to patients undergoing bone marrow transplantation. Drug therapy also has a major impact on kidney function and can modify the dose-response function
Electron and bremsstrahlung penetration and dose calculation
Watts, J. W., Jr.; Burrell, M. O.
1972-01-01
Various techniques for the calculation of electron and bremsstrahlung dose deposition are described. Energy deposition, transmission, and reflection coefficients for electrons incident on plane slabs are presented, and methods for their use in electron dose calculations were developed. A method using the straight-ahead approximation was also developed, and the various methods were compared and found to be in good agreement. Both accurate and approximate methods of calculating bremsstrahlung dose were derived and compared. Approximation is found to give a good estimate of dose where the electron spectrum falls off exponentially with energy.
International Nuclear Information System (INIS)
Giordani, Adelmo Jose; Segreto, Helena Cristina Comodo; Segreto, Roberto Araujo; Medeiros, Regina Bitelli; Oliveira, Jose Salvador R. de
2004-01-01
The objective was to evaluate the precision of the absorbed radiation doses in bone marrow transplant therapy during whole body irradiation. Two-hundred CaSO 4 :Dy + teflon tablets were calibrated in air and in 'phantom'. These tablets were randomly selected and divided in groups of five in the patients' body. The dosimetric readings were obtained using a Harshaw 4000A reader. Nine patients had their entire bodies irradiated in parallel and opposite laterals in a cobalt-60 Alcion II model, with a dose rate of 0.80 Gy/min at 80.5 cm, {(10 ? 10) cm 2 field. The dosimetry of this unit was performed using a Victoreen 500 dosimeter. For the determination of the mean dose at each point evaluated, the individual values of the tablets calibrated in air or 'phantom' were used, resulting in a build up of 2 mm to superficialize the dose at a distance of 300 cm. In 70% of the patients a variation of less than 5% in the dose was obtained. In 30% of the patients this variation was less than 10%, when values obtained were compared to the values calculated at each point. A mean absorption of 14% was seen in the head, and an increase of 2% of the administered dose was seen in the lungs. In patients with latero-lateral distance greater than 35 cm the variation between the calculated doses and the measured doses reached 30% of the desired dose, without the use of compensation filters. The measured values of the absorbed doses at the various anatomic points compared to the desired doses (theoretic) presented a tolerance of ± 10%, considering the existent anatomical differences and when using the individual calibration factors of the tablets. (author)
Practical applications of internal dose calculations
International Nuclear Information System (INIS)
Carbaugh, E.H.
1994-06-01
Accurate estimates of intake magnitude and internal dose are the goal for any assessment of an actual intake of radioactivity. When only one datum is available on which to base estimates, the choices for internal dose assessment become straight-forward: apply the appropriate retention or excretion function, calculate the intake, and calculate the dose. The difficulty comes when multiple data and different types of data become available. Then practical decisions must be made on how to interpret conflicting data, or how to adjust the assumptions and techniques underlying internal dose assessments to give results consistent with the data. This article describes nine types of adjustments which can be incorporated into calculations of intake and internal dose, and then offers several practical insights to dealing with some real-world internal dose puzzles
Dose calculation system for remotely supporting radiotherapy
International Nuclear Information System (INIS)
Saito, K.; Kunieda, E.; Narita, Y.; Kimura, H.; Hirai, M.; Deloar, H. M.; Kaneko, K.; Ozaki, M.; Fujisaki, T.; Myojoyama, A.; Saitoh, H.
2005-01-01
The dose calculation system IMAGINE is being developed keeping in mind remotely supporting external radiation therapy using photon beams. The system is expected to provide an accurate picture of the dose distribution in a patient body, using a Monte Carlo calculation that employs precise models of the patient body and irradiation head. The dose calculation will be performed utilising super-parallel computing at the dose calculation centre, which is equipped with the ITBL computer, and the calculated results will be transferred through a network. The system is intended to support the quality assurance of current, widely carried out radiotherapy and, further, to promote the prevalence of advanced radiotherapy. Prototypes of the modules constituting the system have already been constructed and used to obtain basic data that are necessary in order to decide on the concrete design of the system. The final system will be completed in 2007. (authors)
Text book of dose calculation for operators
International Nuclear Information System (INIS)
Aoyagi, Haruki; Gonda, Kozo
1979-07-01
This is a text book of dose calculation for the operators of the reprocessing factory of Power Reactor and Nuclear Fuel Development Corporation. The radiations considered are beta-ray and gamma-ray. The method used is a point attenuation nuclear integral method. Radiation sources are considered as the assemblies of point sources. Dose from each point source is calculated, then, total dose is obtained by the integration for all sources. Attenuation is calculated by considering the attenuation owing to distance and the absorption by absorbers. The build-up factor is introduced for the correction for scattered gamma-ray. The build-up factor is given in a table for various scatterers. The operators are able to calculate dose by themselves. The results of integral calculation expressed with formulas are given in graphs. (Kato, T.)
Equivalent-spherical-shield neutron dose calculations
International Nuclear Information System (INIS)
Russell, G.J.; Robinson, H.
1988-01-01
Neutron doses through 162-cm-thick spherical shields were calculated to be 1090 and 448 mrem/h for regular and magnetite concrete, respectively. These results bracket the measured data, for reinforced regular concrete, of /approximately/600 mrem/h. The calculated fraction of the high-energy (>20 MeV) dose component also bracketed the experimental data. The measured and calculated doses were for a graphite beam stop bombarded with 100 nA of 800-MeV protons. 6 refs., 2 figs., 1 tab
Dose calculations for severe LWR accident scenarios
International Nuclear Information System (INIS)
Margulies, T.S.; Martin, J.A. Jr.
1984-05-01
This report presents a set of precalculated doses based on a set of postulated accident releases and intended for use in emergency planning and emergency response. Doses were calculated for the PWR (Pressurized Water Reactor) accident categories of the Reactor Safety Study (WASH-1400) using the CRAC (Calculations of Reactor Accident Consequences) code. Whole body and thyroid doses are presented for a selected set of weather cases. For each weather case these calculations were performed for various times and distances including three different dose pathways - cloud (plume) shine, ground shine and inhalation. During an emergency this information can be useful since it is immediately available for projecting offsite radiological doses based on reactor accident sequence information in the absence of plant measurements of emission rates (source terms). It can be used for emergency drill scenario development as well
Doses to the red bone marrow of young people and adults from radiation of natural origin
Energy Technology Data Exchange (ETDEWEB)
Kendall, G M [Childhood Cancer Research Group, University of Oxford, Richards Building, Old Road Campus, Headington, Oxford OX3 7LG (United Kingdom); Fell, T P, E-mail: Gerald.Kendall@ccrg.ox.ac.uk [Health Protection Agency, CRCE, Chilton, Didcot OX11 0RQ, Oxon (United Kingdom)
2011-09-01
Natural radiation sources comprise cosmic rays, terrestrial gamma rays, radionuclides in food and inhaled isotopes of radon with their decay products. These deliver doses to all organs and tissues including red bone marrow (RBM), the tissue in which leukaemia is thought to originate. In this paper we calculate the age-dependent annual RBM doses from natural radiation sources to young people and to adults at average levels of exposure in the UK. The contributions to dose are generally less complex than in the case of doses to foetuses and young children where it is necessary to take into account transfer of radionuclides across the placenta, intakes in mother's milk and changes in gut uptake in young infants. However, there is high uptake of alkaline earths and of similar elements in the developing skeleton and this significantly affects the doses from radioisotopes of these elements, not just in the teens and twenties but through into the fifth decade of life. The total equivalent dose to the RBM from all natural sources of radiation at age 15 years is calculated to be about 1200 {mu}Sv a year at average UK levels, falling to rather less than 1100 {mu}Sv per year in later life; the gentle fall from the late teens onwards reflects the diminishing effect of the high uptakes of radioisotopes of the alkaline earths and of lead in this period. About 60% of the equivalent dose is contributed by the low linear energy transfer (LET) component. Radionuclides in food make the largest contribution to equivalent doses to RBM and much the largest contribution to the absorbed dose from high LET radiation (mainly alpha particles).
Doses to the red bone marrow of young people and adults from radiation of natural origin
International Nuclear Information System (INIS)
Kendall, G M; Fell, T P
2011-01-01
Natural radiation sources comprise cosmic rays, terrestrial gamma rays, radionuclides in food and inhaled isotopes of radon with their decay products. These deliver doses to all organs and tissues including red bone marrow (RBM), the tissue in which leukaemia is thought to originate. In this paper we calculate the age-dependent annual RBM doses from natural radiation sources to young people and to adults at average levels of exposure in the UK. The contributions to dose are generally less complex than in the case of doses to foetuses and young children where it is necessary to take into account transfer of radionuclides across the placenta, intakes in mother's milk and changes in gut uptake in young infants. However, there is high uptake of alkaline earths and of similar elements in the developing skeleton and this significantly affects the doses from radioisotopes of these elements, not just in the teens and twenties but through into the fifth decade of life. The total equivalent dose to the RBM from all natural sources of radiation at age 15 years is calculated to be about 1200 μSv a year at average UK levels, falling to rather less than 1100 μSv per year in later life; the gentle fall from the late teens onwards reflects the diminishing effect of the high uptakes of radioisotopes of the alkaline earths and of lead in this period. About 60% of the equivalent dose is contributed by the low linear energy transfer (LET) component. Radionuclides in food make the largest contribution to equivalent doses to RBM and much the largest contribution to the absorbed dose from high LET radiation (mainly alpha particles).
Georgia fishery study: implications for dose calculations
International Nuclear Information System (INIS)
Turcotte, M.D.S.
1983-01-01
Fish consumption will contribute a major portion of the estimated individual and population doses from L-Reactor liquid releases and Cs-137 remobilization in Steel Creek. It is therefore important that the values for fish consumption used in dose calculations be as realistic as possible. Since publication of the L-Reactor Environmental Information Document (EID), data have become available on sport fishing in the Savannah River. These data provide SRP with site-specific sport fish harvest and consumption values for use in dose calculations. The Georgia fishery data support the total population fish consumption and calculated dose reported in the EID. The data indicate, however, that both the EID average and maximum individual fish consumption have been underestimated, although each to a different degree. The average fish consumption value used in the EID is approximately 3% below the lower limit of the fish consumption range calculated using the Georgia data. A fish consumption value of 11.3 kg/yr should be used to recalculate dose to the average individual from L-Reactor restart. Maximum fish consumption in the EID has been underestimated by approximately 60%, and doses to the maximum individual should also be recalculated. Future dose calculations should utilize an average fish consumption value of 11.3 kg/yr, and a maximum fish consumption value of 34 kg/yr
Bone marrow equivalent prompt dose from two common fallout scenarios
International Nuclear Information System (INIS)
Morris, M.D.; Jones, T.D.; Young, R.W.
1994-01-01
A cell-kinetics model for radiation-induced myelopoiesis has been derived for mice, rats, dogs, sheep, swine, and burros. The model was extended to humans after extensive comparisons with molecular and cellular data from biological experiments and an assortment of predictive/validation tests on animal mortality, cell survival, and cellular repopulation following irradiations. One advantage of the model is that any complex pattern of protracted irradiation can be equated to its equivalent prompt dose. Severity of biological response depends upon target-organ dose, dose rate, and dose fractionation. Epidemiological and animal data are best suited for exposures given in brief periods of time. To use those data to assess risk from protracted human exposures, it is obligatory to model molecular repair and compensatory proliferation in terms of prompt dose. Although the model is somewhat complex both mathematically and biologically, this note describes simple numerical approximations for two common exposure scenarios. Both approximations are easily evaluated on a simple pocket calculator by a health physicist or emergency management officer. 12 refs., 5 figs
The Monte Carlo applied for calculation dose
International Nuclear Information System (INIS)
Peixoto, J.E.
1988-01-01
The Monte Carlo method is showed for the calculation of absorbed dose. The trajectory of the photon is traced simulating sucessive interaction between the photon and the substance that consist the human body simulator. The energy deposition in each interaction of the simulator organ or tissue per photon is also calculated. (C.G.C.) [pt
Dose rate calculations for a reconnaissance vehicle
International Nuclear Information System (INIS)
Grindrod, L.; Mackey, J.; Salmon, M.; Smith, C.; Wall, S.
2005-01-01
A Chemical Nuclear Reconnaissance System (CNRS) has been developed by the British Ministry of Defence to make chemical and radiation measurements on contaminated terrain using appropriate sensors and recording equipment installed in a land rover. A research programme is under way to develop and validate a predictive capability to calculate the build-up of contamination on the vehicle, radiation detector performance and dose rates to the occupants of the vehicle. This paper describes the geometric model of the vehicle and the methodology used for calculations of detector response. Calculated dose rates obtained using the MCBEND Monte Carlo radiation transport computer code in adjoint mode are presented. These address the transient response of the detectors as the vehicle passes through a contaminated area. Calculated dose rates were found to agree with the measured data to be within the experimental uncertainties, thus giving confidence in the shielding model of the vehicle and its application to other scenarios. (authors)
Infinite slab-shield dose calculations
International Nuclear Information System (INIS)
Russell, G.J.
1989-01-01
I calculated neutron and gamma-ray equivalent doses leaking through a variety of infinite (laminate) slab-shields. In the shield computations, I used, as the incident neutron spectrum, the leakage spectrum (<20 MeV) calculated for the LANSCE tungsten production target at 90 degree to the target axis. The shield thickness was fixed at 60 cm. The results of the shield calculations show a minimum in the total leakage equivalent dose if the shield is 40-45 cm of iron followed by 20-15 cm of borated (5% B) polyethylene. High-performance shields can be attained by using multiple laminations. The calculated dose at the shield surface is very dependent on shield material. 4 refs., 4 figs., 1 tab
International Nuclear Information System (INIS)
1977-01-01
Individual and population doses within Danish territory are calculated from hypothetical, severe core-melt accidents at the Swedish nuclear plant at Barsebaeck. The fission product inventory of the Barsebaeck reactor is calculated. The release fractions for the accidents are taken from WASH-1400. Based on parametric studies, doses are calculated for very unfavourable, but not incredible weather conditions. The probability of such conditions in combination with wind direction towards Danish territory is estimated. Doses to bone marrow, lungs, GI-tract and thyroid are calculated based on dose models developed at Risoe. These doses are found to be consistent with doses calculated with the models used in WASH-1400. (author)
Validation of dose calculation programmes for recycling
International Nuclear Information System (INIS)
Menon, Shankar; Brun-Yaba, Christine; Yu, Charley; Cheng, Jing-Jy; Williams, Alexander
2002-12-01
This report contains the results from an international project initiated by the SSI in 1999. The primary purpose of the project was to validate some of the computer codes that are used to estimate radiation doses due to the recycling of scrap metal. The secondary purpose of the validation project was to give a quantification of the level of conservatism in clearance levels based on these codes. Specifically, the computer codes RESRAD-RECYCLE and CERISE were used to calculate radiation doses to individuals during the processing of slightly contaminated material, mainly in Studsvik, Sweden. Calculated external doses were compared with measured data from different steps of the process. The comparison of calculations and measurements shows that the computer code calculations resulted in both overestimations and underestimations of the external doses for different recycling activities. The SSI draws the conclusion that the accuracy is within one order of magnitude when experienced modellers use their programmes to calculate external radiation doses for a recycling process involving material that is mainly contaminated with cobalt-60. No errors in the codes themselves were found. Instead, the inaccuracy seems to depend mainly on the choice of some modelling parameters related to the receptor (e.g., distance, time, etc.) and simplifications made to facilitate modelling with the codes (e.g., object geometry). Clearance levels are often based on studies on enveloping scenarios that are designed to cover all realistic exposure pathways. It is obvious that for most practical cases, this gives a margin to the individual dose constraint (in the order of 10 micro sievert per year within the EC). This may be accentuated by the use of conservative assumptions when modelling the enveloping scenarios. Since there can obviously be a fairly large inaccuracy in the calculations, it seems reasonable to consider some degree of conservatism when establishing clearance levels based on
Validation of dose calculation programmes for recycling
Energy Technology Data Exchange (ETDEWEB)
Menon, Shankar [Menon Consulting, Nykoeping (Sweden); Brun-Yaba, Christine [Inst. de Radioprotection et Securite Nucleaire (France); Yu, Charley; Cheng, Jing-Jy [Argonne National Laboratory, IL (United States). Environmental Assessment Div.; Bjerler, Jan [Studsvik Stensand, Nykoeping (Sweden); Williams, Alexander [Dept. of Energy (United States). Office of Environmental Management
2002-12-01
This report contains the results from an international project initiated by the SSI in 1999. The primary purpose of the project was to validate some of the computer codes that are used to estimate radiation doses due to the recycling of scrap metal. The secondary purpose of the validation project was to give a quantification of the level of conservatism in clearance levels based on these codes. Specifically, the computer codes RESRAD-RECYCLE and CERISE were used to calculate radiation doses to individuals during the processing of slightly contaminated material, mainly in Studsvik, Sweden. Calculated external doses were compared with measured data from different steps of the process. The comparison of calculations and measurements shows that the computer code calculations resulted in both overestimations and underestimations of the external doses for different recycling activities. The SSI draws the conclusion that the accuracy is within one order of magnitude when experienced modellers use their programmes to calculate external radiation doses for a recycling process involving material that is mainly contaminated with cobalt-60. No errors in the codes themselves were found. Instead, the inaccuracy seems to depend mainly on the choice of some modelling parameters related to the receptor (e.g., distance, time, etc.) and simplifications made to facilitate modelling with the codes (e.g., object geometry). Clearance levels are often based on studies on enveloping scenarios that are designed to cover all realistic exposure pathways. It is obvious that for most practical cases, this gives a margin to the individual dose constraint (in the order of 10 micro sievert per year within the EC). This may be accentuated by the use of conservative assumptions when modelling the enveloping scenarios. Since there can obviously be a fairly large inaccuracy in the calculations, it seems reasonable to consider some degree of conservatism when establishing clearance levels based on
Superficial dose evaluation of four dose calculation algorithms
Cao, Ying; Yang, Xiaoyu; Yang, Zhen; Qiu, Xiaoping; Lv, Zhiping; Lei, Mingjun; Liu, Gui; Zhang, Zijian; Hu, Yongmei
2017-08-01
Accurate superficial dose calculation is of major importance because of the skin toxicity in radiotherapy, especially within the initial 2 mm depth being considered more clinically relevant. The aim of this study is to evaluate superficial dose calculation accuracy of four commonly used algorithms in commercially available treatment planning systems (TPS) by Monte Carlo (MC) simulation and film measurements. The superficial dose in a simple geometrical phantom with size of 30 cm×30 cm×30 cm was calculated by PBC (Pencil Beam Convolution), AAA (Analytical Anisotropic Algorithm), AXB (Acuros XB) in Eclipse system and CCC (Collapsed Cone Convolution) in Raystation system under the conditions of source to surface distance (SSD) of 100 cm and field size (FS) of 10×10 cm2. EGSnrc (BEAMnrc/DOSXYZnrc) program was performed to simulate the central axis dose distribution of Varian Trilogy accelerator, combined with measurements of superficial dose distribution by an extrapolation method of multilayer radiochromic films, to estimate the dose calculation accuracy of four algorithms in the superficial region which was recommended in detail by the ICRU (International Commission on Radiation Units and Measurement) and the ICRP (International Commission on Radiological Protection). In superficial region, good agreement was achieved between MC simulation and film extrapolation method, with the mean differences less than 1%, 2% and 5% for 0°, 30° and 60°, respectively. The relative skin dose errors were 0.84%, 1.88% and 3.90%; the mean dose discrepancies (0°, 30° and 60°) between each of four algorithms and MC simulation were (2.41±1.55%, 3.11±2.40%, and 1.53±1.05%), (3.09±3.00%, 3.10±3.01%, and 3.77±3.59%), (3.16±1.50%, 8.70±2.84%, and 18.20±4.10%) and (14.45±4.66%, 10.74±4.54%, and 3.34±3.26%) for AXB, CCC, AAA and PBC respectively. Monte Carlo simulation verified the feasibility of the superficial dose measurements by multilayer Gafchromic films. And the rank
Selection of skin dose calculation methodologies
International Nuclear Information System (INIS)
Farrell, W.E.
1987-01-01
This paper reports that good health physics practice dictates that a dose assessment be performed for any significant skin contamination incident. There are, however, several methodologies that could be used, and while there is probably o single methodology that is proper for all cases of skin contamination, some are clearly more appropriate than others. This can be demonstrated by examining two of the more distinctly different options available for estimating skin dose the calculational methods. The methods compiled by Healy require separate beta and gamma calculations. The beta calculational method is the derived by Loevinger, while the gamma dose is calculated from the equation for dose rate from an infinite plane source with an absorber between the source and the detector. Healy has provided these formulas in graphical form to facilitate rapid dose rate determinations at density thicknesses of 7 and 20 mg/cm 2 . These density thicknesses equate to the regulatory definition of the sensitive layer of the skin and a more arbitrary value to account of beta absorption in contaminated clothing
Dose to red bone marrow of infants, children and adults from radiation of natural origin
Energy Technology Data Exchange (ETDEWEB)
Kendall, G M [Childhood Cancer Research Group, University of Oxford, 57 Woodstock Road, Oxford OX2 6HJ (United Kingdom); Fell, T P; Harrison, J D [Health Protection Agency, Radiation Protection Division, CRCE, Chilton, Didcot OX11 0RQ, Oxon (United Kingdom)], E-mail: Gerald.Kendall@ccrg.ox.ac.uk
2009-06-15
Natural radiation sources contribute much the largest part of the radiation exposure of the average person. This paper examines doses from natural radiation to the red bone marrow, the tissue in which leukaemia is considered to originate, with particular emphasis on doses to children. The most significant contributions are from x-rays and gamma rays, radionuclides in food and inhalation of isotopes of radon and their decay products. External radiation sources and radionuclides other than radon dominate marrow doses at all ages. The variation with age of the various components of marrow dose is considered, including doses received in utero and in each year up to the age of 15. Doses in utero include contributions resulting from the ingestion of radionuclides by the mother and placental transfer to the foetus. Postnatal doses include those from radionuclides in breast-milk and from radionuclides ingested in other foods. Doses are somewhat higher in the first year of life and there is a general slow decline from the second year of life onwards. The low linear energy transfer (LET) component of absorbed dose to the red bone marrow is much larger than the high LET component. However, because of the higher radiation weighting factor for the latter it contributes about 40% of the equivalent dose incurred up to the age of 15.
Agriculture-related radiation dose calculations
International Nuclear Information System (INIS)
Furr, J.M.; Mayberry, J.J.; Waite, D.A.
1987-10-01
Estimates of radiation dose to the public must be made at each stage in the identification and qualification process leading to siting a high-level nuclear waste repository. Specifically considering the ingestion pathway, this paper examines questions of reliability and adequacy of dose calculations in relation to five stages of data availability (geologic province, region, area, location, and mass balance) and three methods of calculation (population, population/food production, and food production driven). Calculations were done using the model PABLM with data for the Permian and Palo Duro Basins and the Deaf Smith County area. Extra effort expended in gathering agricultural data at succeeding environmental characterization levels does not appear justified, since dose estimates do not differ greatly; that effort would be better spent determining usage of food types that contribute most to the total dose; and that consumption rate and the air dispersion factor are critical to assessment of radiation dose via the ingestion pathway. 17 refs., 9 figs., 32 tabs
A dose error evaluation study for 4D dose calculations
Milz, Stefan; Wilkens, Jan J.; Ullrich, Wolfgang
2014-10-01
Previous studies have shown that respiration induced motion is not negligible for Stereotactic Body Radiation Therapy. The intrafractional breathing induced motion influences the delivered dose distribution on the underlying patient geometry such as the lung or the abdomen. If a static geometry is used, a planning process for these indications does not represent the entire dynamic process. The quality of a full 4D dose calculation approach depends on the dose coordinate transformation process between deformable geometries. This article provides an evaluation study that introduces an advanced method to verify the quality of numerical dose transformation generated by four different algorithms. The used transformation metric value is based on the deviation of the dose mass histogram (DMH) and the mean dose throughout dose transformation. The study compares the results of four algorithms. In general, two elementary approaches are used: dose mapping and energy transformation. Dose interpolation (DIM) and an advanced concept, so called divergent dose mapping model (dDMM), are used for dose mapping. The algorithms are compared to the basic energy transformation model (bETM) and the energy mass congruent mapping (EMCM). For evaluation 900 small sample regions of interest (ROI) are generated inside an exemplary lung geometry (4DCT). A homogeneous fluence distribution is assumed for dose calculation inside the ROIs. The dose transformations are performed with the four different algorithms. The study investigates the DMH-metric and the mean dose metric for different scenarios (voxel sizes: 8 mm, 4 mm, 2 mm, 1 mm 9 different breathing phases). dDMM achieves the best transformation accuracy in all measured test cases with 3-5% lower errors than the other models. The results of dDMM are reasonable and most efficient in this study, although the model is simple and easy to implement. The EMCM model also achieved suitable results, but the approach requires a more complex
Dose calculation in brachytherapy with microcomputers
International Nuclear Information System (INIS)
Elbern, A.W.
1989-01-01
The computer algorithms, that allow the calculation of brachytherapy doses and its graphic representation for implants, using programs developed for Pc microcomputers are presented. These algorithms allow to localized the sources in space, from their projection in radiographics images and trace isodose counter. (C.G.C.) [pt
Genetic and mean bone-marrow doses from medical use of unsealed radioisotopes
International Nuclear Information System (INIS)
Keam, D.W.
1980-06-01
Annual genetically significant and mean bone-marrow doses to the Australian population arising from the medical use of unsealed radioisotopes are derived for the year 1970 using the results of a survey carried out at that time and published data on doses to individuals resulting from such use. Values of 3.9 and 38 microgray for the annual (per capita) genetic and mean bone-marrow doses respectively are reported, which are similar to those reported for other countries at about that time
Dose calculations for intakes of ore dust
International Nuclear Information System (INIS)
O'Brien, R.S.
1998-08-01
This report describes a methodology for calculating the committed effective dose for mixtures of radionuclides, such as those which occur in natural radioactive ores and dusts. The formulae are derived from first principles, with the use of reasonable assumptions concerning the nature and behaviour of the radionuclide mixtures. The calculations are complicated because these 'ores' contain a range of particle sizes, have different degrees of solubility in blood and other body fluids, and also have different biokinetic clearance characteristics from the organs and tissues in the body. The naturally occurring radionuclides also tend to occur in series, i.e. one is produced by the radioactive decay of another 'parent' radionuclide. The formulae derived here can be used, in conjunction with a model such as LUDEP, for calculating total dose resulting from inhalation and/or ingestion of a mixture of radionuclides, and also for deriving annual limits on intake and derived air concentrations for these mixtures
Low-dose radiation-induced adaptive response in bone marrow cells of mice
International Nuclear Information System (INIS)
Farooqi, Zeba; Kesavan, P.C.
1993-01-01
Using bone marrow cells of whole body irradiated mice, the cytogenetic adaptive response induced by low conditioning doses of gamma-rays was investigated. The conditioning doses (0.025 and 0.05 Gy) were given at a dose-rate of 1.67 Gy/min. The challenging dose of 1 Gy was given at a dose-rate of 0.045 Gy/s. The challenging dose was given at different time intervals after the conditioning dose. The time intervals between the conditioning dose and challenging dose were 2, 7.5, 13, 18.5 and 24 h. When the time interval between the conditioning dose and the challenging dose was 2 h, both conditioning doses (0.025 and 0.05 Gy) reduced the frequency of MNPCEs and chromosomal aberrations in the bone marrow cells. The data collected at different time intervals (7.5, 13, 18.5 h) reveal that the radioadaptive response persisted for a longer time when the lower conditioning dose (0.025 Gy) was given. With the higher conditioning dose (0.05 Gy), the radioadaptive response disappeared after a time interval of 13 h. When the time interval between the conditioning dose and the challenging doses was 18.5 or 24 h, only the lower conditioning dose appeared effective in inducing the radioadaptive response
Homing regularity of different doses bone marrow transplantation in allogeneic hosts
International Nuclear Information System (INIS)
Sun Suping; Cai Jianming; Xiang Yingsong; Zhao Fang; Huang Dingde; Gao Jianguo; Yang Rujun
2001-01-01
Objective: To explore the homing regularity of different doses of bone marrow cell transplantation. Method: An allogeneic mouse model was used. The homing status of different dose groups from the first day to the forth day after transplantation were observed. Results: The rate of positive cells in bone marrow and spleen: differences among four groups was not significant. The rate of positive cells of third day was highest among four days (P<0.01). A phenomenon that homing-mobilization-re-homing could be observed. The homing efficiency: low dose groups were higher than that high dose groups (P<0.01). Conclusion: The homing efficiency of low dose groups is higher than that of the high dose groups in certain range, the routine method of transplanting a large quantities cells by a single injection may be an waste
Energy Technology Data Exchange (ETDEWEB)
Manning, Grainne [Biological Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 ORQ (United Kingdom); Taylor, Kristina [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON (Canada); Finnon, Paul [Biological Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 ORQ (United Kingdom); Lemon, Jennifer A.; Boreham, Douglas R. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON (Canada); Badie, Christophe, E-mail: christophe.badie@phe.gov.uk [Biological Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 ORQ (United Kingdom)
2014-12-15
Highlights: • Mice received either a range of {sup 18}F-FDG activities or whole body X-ray doses. • Blood samples were collected at 24 and 43 h for MN-RET and QPCR analysis. • Regression analysis showed that both types of exposure produced a linear response. • BM doses of 33 mGy ({sup 18}F-FDG) and 25 mGy X-rays were significantly higher than controls. • No significant difference between internal ({sup 18}F-FDG) and external (X-ray) was found. - Abstract: The purpose of this study was to quantify the poorly understood radiation doses to murine bone marrow and blood from whole-body fluorine 18 ({sup 18}F)-fluorodeoxyglucose (FDG) positron emission tomography (PET), by using specific biomarkers and comparing with whole body external low dose exposures. Groups of 3–5 mice were randomly assigned to 10 groups, each receiving either a different activity of {sup 18}F-FDG: 0–37 MBq or whole body irradiated with corresponding doses of 0–300 mGy X-rays. Blood samples were collected at 24 h and at 43 h for reticulocyte micronucleus assays and QPCR analysis of gene expression in peripheral blood leukocytes. Blood and bone marrow dose estimates were calculated from injected activities of {sup 18}F-FDG and were based on a recommended ICRP model. Doses to the bone marrow corresponding to 33.43 mGy and above for internal {sup 18}F-FDG exposure and to 25 mGy and above for external X-ray exposure, showed significant increases in radiation-induced MN-RET formation relative to controls (P < 0.05). Regression analysis showed that both types of exposure produced a linear response with linear regression analysis giving R{sup 2} of 0.992 and 0.999 for respectively internal and external exposure. No significant difference between the two data sets was found with a P-value of 0.493. In vivo gene expression dose–responses at 24 h for Bbc3 and Cdkn1 were similar for {sup 18}F-FDG and X-ray exposures, with significant modifications occurring for doses over 300 mGy for Bbc3
Effects of low-doses of Bacillus spp. from permafrost on differentiation of bone marrow cells.
Kalyonova, L F; Novikova, M A; Kostolomova, E G
2015-01-01
The effects of a new microorganism species (Bacillus spp., strain M3) isolated from permafrost specimens from Central Yakutia (Mamontova Mountain) on the bone marrow hemopoiesis were studied on laboratory mice. Analysis of the count and immunophenotype of bone marrow cells indicated that even in low doses (1000-5000 microbial cells) these microorganisms modulated hemopoiesis and lymphopoiesis activity. The percentage of early hemopoietic precursors (CD117(+)CD34(-)) increased, intensity of lymphocyte precursor proliferation and differentiation (CD25(+)CD44(-)) decreased, and the percentage of lymphocytes released from the bone marrow (CD25(+)CD44(+)) increased on day 21 after injection of the bacteria. These changes in activity of hemopoiesis were associated with changes in the level of regulatory T lymphocytes (reduced expression of TCRαβ) and were most likely compensatory. The possibility of modulating hemopoiesis activity in the bone marrow by low doses of one microorganism strain isolated from the permafrost could be useful for evaluating the effects of other low dose bacteria on the bone marrow hemopoiesis.
Determination of gonad, eye and bone marrow doses with EMI-5005 head and whole body scans
International Nuclear Information System (INIS)
Nishizawa, Kanae; Iwata, Takeo; Furuya, Yoshiro; Maruyama, Takashi; Hashizume, Tadashi.
1979-01-01
Dose determinations of tissues and organs during head and whole body scanning with an EMI computed tomographic equipment have been carried out using a Rando woman phantom. The surface dose on the phantom was measured with a Sakura lith Contact film dosimeter system. The absorbed doses in the eyes, thyroids, ovaries and the bone marrow were measured with a thermoluminescent dosimeter. The resultant surface doses for head scanning were 2.8 rad (28 mGy) per scan at maximum and 0.26 rad (2.6 mGy) per scan at minimum, and the doses for whole body scanning were 2.7 rad (27 mGy) per scan at maximum and 0.1 rad (1.0 mGy) per scan at minimum. For the complete gynecological scanning consisting of 8 slices, the eye, thyroid, ovary and the bone marrow dose was 2.4 mrad (24 μGy), 3.5 mrad (35 μGy), 500 mrad (5 mGy) and 225 mrad (2.25 mGy), respectively. And, for a typical head scanning consisting of 5 slices, the eye, thyroid, ovary and the bone marrow dose was 1400 mrad (14 mGy), 46 mrad (460 μGy), 0.60 mrad (6 μGy) and 73 mrad (730 μGy), respectively. (author)
Validation of Dose Calculation Codes for Clearance
International Nuclear Information System (INIS)
Menon, S.; Wirendal, B.; Bjerler, J.; Studsvik; Teunckens, L.
2003-01-01
Various international and national bodies such as the International Atomic Energy Agency, the European Commission, the US Nuclear Regulatory Commission have put forward proposals or guidance documents to regulate the ''clearance'' from regulatory control of very low level radioactive material, in order to allow its recycling as a material management practice. All these proposals are based on predicted scenarios for subsequent utilization of the released materials. The calculation models used in these scenarios tend to utilize conservative data regarding exposure times and dose uptake as well as other assumptions as a safeguard against uncertainties. None of these models has ever been validated by comparison with the actual real life practice of recycling. An international project was organized in order to validate some of the assumptions made in these calculation models, and, thereby, better assess the radiological consequences of recycling on a practical large scale
Calculation of dose distribution above contaminated soil
Kuroda, Junya; Tenzou, Hideki; Manabe, Seiya; Iwakura, Yukiko
2017-07-01
The purpose of this study was to assess the relationship between altitude and the distribution of the ambient dose rate in the air over soil decontamination area by using PHITS simulation code. The geometry configuration was 1000 m ×1000 m area and 1m in soil depth and 100m in altitude from the ground to simulate the area of residences or a school grounds. The contaminated region is supposed to be uniformly contaminated by Cs-137 γ radiation sources. The air dose distribution and space resolution was evaluated for flux of the gamma rays at each altitude, 1, 5, 10, and 20m. The effect of decontamination was calculated by defining sharpness S. S was the ratio of an average flux and a flux at the center of denomination area in each altitude. The suitable flight altitude of the drone is found to be less than 15m above a residence and 31m above a school grounds to confirm the decontamination effect. The calculation results can be a help to determine a flight planning of a drone to minimize the clash risk.
International Nuclear Information System (INIS)
Zhang Liyuan; Yang Shun; Zhang Ye; Zhang Mingzhi; Jiang Jiagui; Jiang Jianping
2007-01-01
Objective: To investigate if low dose radiation can stimulate the haematogenesis reconstitution of the recipient after bone marrow transplantation in mice. Methods: Bone marrow cells were irradiated in vitro by different low dose radiation and then cultured in vitro. 3 H-TdR incorporation was used to measure the reproductive activity of cells, and then the radiation dose with the best stimulating effect was determined. The donator myeloid cells were exposed to low dose radiation before the recipient mice received bone marrow transplantation; then the irradiated myeloid cells were infused to the recipient; and lastly, the counts of peripheral blood cells (PBC) and bone marrow mononuclear cells (BMMNC) were monitored in order to observe the effect of low dose radiation on haematogenesis reconstitution of the recipient animal after bone marrow transplantation. Results: The reproductive activity of the bone marrow cells irradiated by 6 and 8 cGy could be improved significantly in vitro. When the recipient mice received bone marrow transplantation of the myeloid cells after low dose radiation, the counts of BMMNC and PBC were higher than those in the control group (P<0.05). Conclusions: Low dose radiation can stimulate the haematogenesis reconstitution of the recipient after bone marrow transplantation. (authors)
Apoptosis of bone marrow leukemia cells in mice after low dose radiation at different time
International Nuclear Information System (INIS)
Li Guangyu; Yu Mingming; Li Xianjun; Liu Zhixiang
2007-01-01
Objective: To investigate the apoptosis of bone marrow leukemia cell in mice after low dose radiation (LDR) at different time and the experimental basis for LDR auxiliary therapy on leukemia. Methods: WEHI-3 cells were injected into BALB/c mice through tail veins to make an experimental mice model of myelornonocytic leukemia. 60 leukemia mice models were divided half-and half. 30 mice models in experimental group were irradiated with LDR of 75mGy at the same time while the others 30 in the control group were not. 6 mice models with LDR and 6 mice models without LDR would be killed at the time the 1st day, the 2nd day, the 3rd day, the 5th day- and the l0th day after LDR in order to extract bone marrow samples. The apoptosis percentage of leukemia cells in bone marrow was examined. Results: The apoptosis percentage of leukemia cells in experimental group was increasing after LDR and went to top on the 2nd day and the 3rd day. The apoptosis percentage of leukemia cells was remarkably different between experimental and control group, all P<0.05. Conclusion: LDR could significantly increase the apoptosis percentage of bone marrow leukemia cells in mice. Its mechanism is remarkably different in kill and wound of big dose radiation to tumour cells. It is probably related to of the increase immune exciting response as to promote some cytokine secretion, in leukemia mice. (authors)
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
Marrow, ovary, and breast doses delivered by CHR diagnostic x-ray examinations: an update
International Nuclear Information System (INIS)
Schlenker, R.A.; Oltman, B.G.
1977-01-01
The mean absorbed dose averaged over the marrow volume in a RANDO phantom is 232 +- 14 mrad and 175 +- 26 mrad when the ANL examination is made using 1 mm Al and 3 mm Al added filtration, respectively; it is 606 +- 69 mrad when the MIT examination is made. The absorbed dose averaged over the ovaries is 243 +- 25 mrad and 162 +- 38 mrad for 1 mm Al and 3 mm Al at ANL and 606 +- 40 mrad for the MIT examination. Breast doses are 388 +- 35 mrad, 226 +- 9 mrad, and 333 +- 103 mrad. Dose reduction could be achieved by using a faster film-screen combination for the MIT examination, by routinely using 3 mm Al added filtration at ANL and by improving the collimation at ANL
International Nuclear Information System (INIS)
Cristy, M.
1980-01-01
Mathematical phantoms of the human body at various ages are employed with Monte Carlo radiation transport codes for calculation of photon specific absorbed fractions. The author has developed a pediatric phantom series based on the design of the adult phantom, but with explicit equations for each organ so that organ sizes and marrow distributions could be assigned properly. Since the phantoms comprise simple geometric shapes, predictive dose capability is limited when geometry is critical to the calculation. Hence, there is a demand for better phantom design in situations where geometry is critical, such as for external irradiation or for internal emitters with low energy photons. Recent advances in computerized axial tomography (CAT) present the potential for derivation of anatomical information, which is so critical to development of phantoms, and ongoing developmental work on compuer architecture to handle large arrays for Monte Carlo calculations should make complex-geometry dose calculations economically feasible within this decade
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
Sequential changes in bone marrow architecture during continuous low dose gamma irradiation
International Nuclear Information System (INIS)
Seed, T.M.; Chubb, G.T.; Tolle, D.V.
1981-01-01
Beagles continuously exposed to low daily doses (10 R) of whole-body 60 Co ν-radiation are prone to develop either early occurring aplasstic anemia or late occurring myeloproliferative disorders. In this study, we have examined by a combination of light microscopy and scanning and transmission electron microscopy the sequential changes in the morphology of biopsied rib bone marrow of continuously irradiated dogs that developed either aplastic anemia, myelofibrosis, or myelogenous leukemia. Characteristic modifications of key elements of marrow architecture have been observed during preclinical and clinical phases of these hemopathological conditions. These architectural changes during preclinical phases appear to be related to the pathological progression to each of the radiation-induced hemopathological end points
Validation of GPU based TomoTherapy dose calculation engine.
Chen, Quan; Lu, Weiguo; Chen, Yu; Chen, Mingli; Henderson, Douglas; Sterpin, Edmond
2012-04-01
The graphic processing unit (GPU) based TomoTherapy convolution/superposition(C/S) dose engine (GPU dose engine) achieves a dramatic performance improvement over the traditional CPU-cluster based TomoTherapy dose engine (CPU dose engine). Besides the architecture difference between the GPU and CPU, there are several algorithm changes from the CPU dose engine to the GPU dose engine. These changes made the GPU dose slightly different from the CPU-cluster dose. In order for the commercial release of the GPU dose engine, its accuracy has to be validated. Thirty eight TomoTherapy phantom plans and 19 patient plans were calculated with both dose engines to evaluate the equivalency between the two dose engines. Gamma indices (Γ) were used for the equivalency evaluation. The GPU dose was further verified with the absolute point dose measurement with ion chamber and film measurements for phantom plans. Monte Carlo calculation was used as a reference for both dose engines in the accuracy evaluation in heterogeneous phantom and actual patients. The GPU dose engine showed excellent agreement with the current CPU dose engine. The majority of cases had over 99.99% of voxels with Γ(1%, 1 mm) engine also showed similar degree of accuracy in heterogeneous media as the current TomoTherapy dose engine. It is verified and validated that the ultrafast TomoTherapy GPU dose engine can safely replace the existing TomoTherapy cluster based dose engine without degradation in dose accuracy.
International Nuclear Information System (INIS)
Johnke, R.M.; Abernathy, R.S.
1990-01-01
The present investigation is a continuation of efforts to characterize the radioprotective potential of priming with vincristine (VcR). In this study, the postirradiation recovery kinetics of the marrow's hematopoietic stem cell, progenitor cell, and stromal cell compartments were monitored following exposure to a range of sublethal radiation doses to determine (a) the optimal VcR/radiation intertreatment interval for achieving maximal hematopoietic protection, (b) whether this optimal interval is influenced by the dose of radiation administered, and (c) whether the radioprotection observed involves the hematopoietic stroma. The results demonstrate that the degree of radioprotection observed was significantly influenced by the scheduling of the VcR priming dose with respect to the radiation exposure. An intertreatment interval of 24 h provided maximal radioprotective benefit irrespective of the radiation dose administered. Additionally, the radioprotection following VcR priming appeared to be more the result of an accelerated recovery in the hematopoietic stem cell and progenitor cell compartments than a change in their intrinsic radiosensitivity. The data also suggest that this accelerated recovery was not a consequence of greater radioprotection of marrow stroma. Finally, the radioprotection observed following VcR priming did not appear to involve a selective lineage response by either the erythroid or the granulomonocytic progenitor compartments
PCXMC. A PC-based Monte Carlo program for calculating patient doses in medical x-ray examinations
International Nuclear Information System (INIS)
Tapiovaara, M.; Lakkisto, M.; Servomaa, A.
1997-02-01
The report describes PCXMC, a Monte Carlo program for calculating patients' organ doses and the effective dose in medical x-ray examinations. The organs considered are: the active bone marrow, adrenals, brain, breasts, colon (upper and lower large intestine), gall bladder, heats, kidneys, liver, lungs, muscle, oesophagus, ovaries, pancreas, skeleton, skin, small intestine, spleen, stomach, testes, thymes, thyroid, urinary bladder, and uterus. (42 refs.)
Dose response and factors related to interstitial pneumonitis after bone marrow transplant
International Nuclear Information System (INIS)
Sampath, Sagus; Schultheiss, Timothy E.; Wong, Jeffrey
2005-01-01
Purpose: Total body irradiation (TBI) and chemotherapy are common components of conditioning regimens for bone marrow transplantation. Interstitial pneumonitis (IP) is a known regimen-related complication. Using published data of IP in a multivariate logistic regression, this study sought to identify the parameters in the bone marrow transplantation conditioning regimen that were significantly associated with IP and to establish a radiation dose-response function. Methods and Materials: A retrospective review was conducted of articles that reported IP incidence along with lung dose, fractionation, dose rate, and chemotherapy regimen. In the final analysis, 20 articles (n = 1090 patients), consisting of 26 distinct TBI/chemotherapy regimens, were included in the analysis. Multivariate logistic regression was performed to determine dosimetric and chemotherapeutic factors that influenced the incidence of IP. Results: A logistic model was generated from patients receiving daily fractions of radiation. In this model, lung dose, cyclophosphamide dose, and the addition of busulfan were significantly associated with IP. An incidence of 3%-4% with chemotherapy-only conditioning regimens is estimated from the models. The α/β value of the linear-quadratic model was estimated to be 2.8 Gy. The dose eliciting a 50% incidence, D 50 , for IP after 120 mg/kg of cyclophosphamide was 8.8 Gy; in the absence of chemotherapy, the estimated D 50 is 10.6 Gy. No dose rate effect was observed. The use of busulfan as a substitute for radiation is equivalent to treating with 14.8 Gy in 4 fractions with 50% transmission blocks shielding the lung. The logistic regression failed to find a model that adequately fit the multiple-fraction-per-day data. Conclusions: Dose responses for both lung radiation dose and cyclophosphamide dose were identified. A conditioning regimen of 12 Gy TBI in 6 daily fractions induces an IP incidence of about 11% in the absence of lung shielding. Shielding the lung
3'-deoxy-3'-[18F]fluorothymidine PET Quantification of Bone Marrow Response to Radiation Dose
International Nuclear Information System (INIS)
McGuire, Sarah M.; Menda, Yusuf; Boles Ponto, Laura L.; Gross, Brandie; Buatti, John; Bayouth, John E.
2011-01-01
Purpose: The purpose of this study was to quantify the relationship of bone marrow response to radiation dose, using 3'-deoxy-3'-[ 18 F]fluorothymidine ([ 18 F]FLT)-labeled uptake quantified in positron-emission tomography (PET) scans. Methods and Materials: Pre- and post-Week 1 treatment [ 18 F]FLT PET images were registered to the CT images used to create the radiation treatment plan. Changes in [ 18 F]FLT uptake values were measured using profile data of standardized uptake values (SUVs) and doses along the vertebral bodies located at a field border where a range of radiation doses were present for 10 patients. Data from the profile measurements were grouped into 1 Gy dose bins from 1 to 9 Gy to compare SUV changes for all patients. Additionally, the maximum pretreatment, the post-Week 1 treatment, and the dose values located within the C6-T7 vertebrae that straddled the field edge were measured for all patients. Results: Both the profile and the individual vertebral data showed a strong correlation between SUV change and radiation dose. Relative differences in SUVs between bins >1 Gy and 18 F]FLT PET images for identifying active bone marrow and monitoring changes due to radiation dose. Additionally, the change in [ 18 F]FLT uptake observed in bone marrow for different weekly doses suggests potential dose thresholds for reducing bone marrow toxicity.
Lipid peroxidation in microsomes of murine bone marrow after low-dose γ-irradiation
International Nuclear Information System (INIS)
Schwenke, K.; Coslar, S.; Muehlensiepen, H.; Altman, K.I.; Feinendegen, L.E.
1994-01-01
The principal aim of the study was to investigate the effect of low-dose γ-irradiation on lipid peroxidation (LPO) in murine bone marrow. To this end, the degree of LPO in suspensions of microsomes of murine bone marrow cells (BMC) was determined in terms of malondialdehyde (MDA) formation after whole-body or in vitro exposure to various doses of γ-radiation. These effects were compared to some extent with similar effects in liver and spleen preparations. As to the effect of γ-irradiation on LPO in BMC, the response depends on the dose level and on whether whole-body or in vitro exposures are involved. Whole-body irradiation did not result in an increase in LPO in BMC microsomes, even at such high doses as 15 Gy, although hepatic microsomes showed a marked increase. In contrast, in vitro irradiation of BMC microsomes with 0.1, 10 and 50 Gy brought about an increase in LPO. This increase was already significant (P < 0.05) at 0.1 Gy following a post-irradiation incubation and substantial at 50 Gy, even without subsequent incubation. The results show that low doses of γ-irradiation are able to induce an elevation of LPO in murine BMC microsomes, but only after in vitro irradiation. In the case of whole-body irradiation cellular radical scavengers and other metabolic reactions may prevent a measurable increase in LPO. This is partly illustrated by the case of vitamin-E deficiency, where a substantial increase in LPO in BMC microsomes is observed even without γ-irradiation in comparison with euvitaminotic mice because normally occurring radicals are not scavenged sufficiently. (orig.)
International Nuclear Information System (INIS)
Swindon, T.N.; Morris, N.D.
1980-06-01
The results of a national survey of radiological procedures used for diagnosis and therapy in medicine, dentistry and chiropracty are reviewed. Statistical data for the distribution and frequency of various procedures in Australian hospitals and practices are summarised, together with their associated radiation doses. Annual genetically significant and mean bone-marrow doses to the Australian population arising from these procedures are derived for the survey year of 1970. Values of 176 microgray and 651 microgray for the annual (per capita) genetic and mean bone-marrow doses respectively are reported. These compare closely with corresponding estimates in other countries with similar medical practices to those in Australia
Fagioli, Franca; Quarello, Paola; Pollichieni, Simona; Lamparelli, Teresa; Berger, Massimo; Benedetti, Fabio; Barat, Veronica; Marciano, Renato; Rambaldi, Alessandro; Bacigalupo, Andrea; Sacchi, Nicoletta
2014-01-01
In this study, we investigated the factors affecting cell dose harvest and the role of cell dose on outcome. We analysed data from a cohort of 703 patients who underwent unrelated bone marrow transplantation facilitated by IBMDR in GITMO centers between 2002 and 2008. The median-infused cell doses is 3.7 × 10(8)/kg, the correlation between the nucleated cells requested from transplant centers and those harvested by collection centers was adequate. A harvested/requested cells ratio lower than 0.5 was observed only in 3% of harvests. A volume of harvested marrow higher than the median value of 1270 ml was related to a significant lower infused cell dose (χ(2): 44.4; P < 0.001). No patient- or donor-related variables significantly influenced the cell dose except for the recipient younger age (χ(2): 95.7; P < 0.001) and non-malignant diseases (χ(2): 33.8; P < 0.001). The cell dose resulted an independent predictor factor for a better outcome in patients affected by non-malignant disease (P = 0.05) while early disease malignant patients receiving a lower cell dose showed a higher risk of relapse (P = 0.05).
Study on human mesenchymal stem cells from bone marrow pretreated with low dose radiation
International Nuclear Information System (INIS)
Yang Yan; Wang Guangjun; Wang Juan
2008-01-01
Objective: To study effects of human bone marrow mesenchymal stem cells (hBM-MSC) from bone marrow pretreated with low dose radiation (LDR). Methods: The cells were the hBM-MSC. They were exposed to X rays at the dose of 50 mGy, 75 mGy, 100 mGy (dose rate 12.5 mGy/min). The growth curve, cell cycle and apoptosis of hBM-MSC treated by LDR were investigated. The content changes of stem cell factor(SCF), interleukin-6 (IL-6), macrophage colony stimulating factor(M-CSF) secreted by hBM-MSC after treated by LDR were determined by enzyme linked immunosorbent assay method. Results: The growth rates of hBM-MSC treated by LDR obviously increase from 72 h. The cell cycle and apoptosis were examined with FORTRAN Atomatic Checkout Systom. The results show that the G 0 /G 1 stage cells decrease after exposure to LDR, the percent of G 0 /G 1 stage cells of 75 mGy at 72 h is the lowest(30.86%). However, the S stage cells percentage gradually increase at 48 h and 72 h. The most one is 75 mGy group at 72 h, which reaches to 68.88%. The apoptosis percentages have increased tendency at 24 h and 48h in all dose groups, especially in 100 mGy at 24 h(25.99%), while have decreased tendency at 72 h and the most decreased group is the 50 mGy(6.8%), transient enhancement of apoptosis in the early stage and soon being decreased. The contents of SCF have increased tendency at 24 h, 48 h. As for IL-6, the contents in different dose groups at 24 h and 48 h have up-regulation. These groups, 50 mGy at 24 h, 48 h, 75 mGy at 24 h, 48 h, 100 mGy at 24 h have statistical difference compared with their control groups respectively. The content of IL-6 has greatest enhancement at dose of 50 mGy. The contents of M-SCF in all the groups at 24 h, 48 h and 72 h except for the 50 mGy dose at 72 h have also been found increased. The greatest increased content occur in the 75 mGy dose group at 72 h. Conclusion: This conclusion show that LDR has hormesis effect on hBM-MSC in cell growth, cell cycle and content
Recommendations on dose buildup factors used in models for calculating gamma doses for a plume
International Nuclear Information System (INIS)
Hedemann Jensen, P.; Thykier-Nielsen, S.
1980-09-01
Calculations of external γ-doses from radioactivity released to the atmosphere have been made using different dose buildup factor formulas. Some of the dose buildup factor formulas are used by the Nordic countries in their respective γ-dose models. A comparison of calculated γ-doses using these dose buildup factors shows that the γ-doses can be significantly dependent on the buildup factor formula used in the calculation. Increasing differences occur for increasing plume height, crosswind distance, and atmospheric stability and also for decreasing downwind distance. It is concluded that the most accurate γ-dose can be calculated by use of Capo's polynomial buildup factor formula. Capo-coefficients have been calculated and shown in this report for γ-energies below the original lower limit given by Capo. (author)
International Nuclear Information System (INIS)
Ichimaru, M.; Ishimaru, T.; Mikami, M.; Matsunaga, M.
1982-01-01
The relationship between atomic bomb exposure and the incidence of multiple myeloma has been examined in a fixed cohort of atomic bomb survivors and controls in the life-span study sample for Hiroshima and Nagasaki. From October 1950 to December 1976, 29 cases of multiple myeloma were confirmed in this sample. Our analysis shows that the standardized relative risk (RR) adjusted for city, sex, and age at the time of bombings (ATB) increased with marrow-absorbed radiation dose. The increased RR does not appear to differ between cities or sexes and is demonstrable only for those survivors whose age ATB was between 20 and 59 years. The estimated risk in these individuals is approximately 0.48 cases/million person-years/rad for bone marrow total dose. This excess risk did not become apparent in individuals receiving 50 rad or more in marrow total dose until 20 years or more after exposure
Development of internal dose calculation programing via food ingestion
International Nuclear Information System (INIS)
Kim, H. J.; Lee, W. K.; Lee, M. S.
1998-01-01
Most of dose for public via ingestion pathway is calculating for considering several pathways; which start from radioactive material released from a nuclear power plant to diffusion and migration. But in order to model these complicate pathways mathematically, some assumptions are essential and lots of input data related with pathways are demanded. Since there is uncertainty related with environment in these assumptions and input data, the accuracy of dose calculating result is not reliable. To reduce, therefore, these uncertain assumptions and inputs, this paper presents exposure dose calculating method using the activity of environmental sample detected in any pathway. Application of dose calculation is aim at peoples around KORI nuclear power plant and the value that is used to dose conversion factor recommended in ICRP Publ. 60
International Nuclear Information System (INIS)
Kempen-Harteveld, M. Loes van; Belkacemi, Yazid; Kal, Henk B.; Labopin, Myriam; Frassoni, Francesco
2002-01-01
Purpose: To determine a dose-effect relationship for cataract induction, the tissue-specific parameter, α/β, and the rate of repair of sublethal damage, μ value, in the linear-quadratic formula have to be known. To obtain these parameters for the human eye lens, a large series of patients treated with different doses and dose rates is required. The data of patients with acute leukemia treated with single-dose total body irradiation (STBI) and bone marrow transplantation (BMT) collected by the European Group for Blood and Marrow Transplantation were analyzed. Methods and Materials: The data of 495 patients who underwent BMT for acute leukemia, who had STBI as part of their conditioning regimen, were analyzed using the linear-quadratic concept. The end point was the incidence of cataract formation after BMT. Of the analyzed patients, 175 were registered as having cataracts. Biologic effective doses (BEDs) for different sets of values for α/β and μ were calculated for each patient. With Cox regression analysis, using the overall chi-square test as the parameter evaluating the goodness of fit, α/β and μ values were found. Risk factors for cataract induction were the BED of the applied TBI regimen, allogeneic BMT, steroid therapy for >14 weeks, and heparin administration. To avoid the influence of steroid therapy and heparin on cataract induction, patients who received steroid or heparin treatment were excluded, leaving only the BED as a risk factor. Next, the most likely set of α/β and μ values was obtained. With this set, the cataract-free survival rates were calculated for specific BED intervals, according to the Kaplan-Meier method. From these calculations, cataract incidences were obtained as function of the BED at 120 months after STBI. Results: The use of BED instead of the TBI dose enabled the incidence of cataract formation to be predicted in a reasonably consistent way. With Cox regression analysis for all STBI data, a maximal chi-square value was
Method for dose calculation in intracavitary irradiation of endometrical carcinoma
International Nuclear Information System (INIS)
Zevrieva, I.F.; Ivashchenko, N.T.; Musapirova, N.A.; Fel'dman, S.Z.; Sajbekov, T.S.
1979-01-01
A method for dose calculation for the conditions of intracavitary gamma therapy of endometrial carcinoma using spherical and linear 60 Co sources was elaborated. Calculations of dose rates for different amount and orientation of spherical radiation sources and for different planes were made with the aid of BEhSM-4M computer. Dosimet were made with the aid of BEhSM-4M computer. Dosimetric study of dose fields was made using a phantom imitating the real conditions of irradiation. Discrepancies between experimental and calculated values are within the limits of the experiment accuracy
Bone marrow concentrate promotes bone regeneration with a suboptimal-dose of rhBMP-2.
Egashira, Kazuhiro; Sumita, Yoshinori; Zhong, Weijian; I, Takashi; Ohba, Seigo; Nagai, Kazuhiro; Asahina, Izumi
2018-01-01
Bone marrow concentrate (BMC), which is enriched in mononuclear cells (MNCs) and platelets, has recently attracted the attention of clinicians as a new optional means for bone engineering. We previously reported that the osteoinductive effect of bone morphogenetic protein-2 (BMP-2) could be enhanced synergistically by co-transplantation of peripheral blood (PB)-derived platelet-rich plasma (PRP). This study aims to investigate whether BMC can effectively promote bone formation induced by low-dose BMP-2, thereby reducing the undesirable side-effects of BMP-2, compared to PRP. Human BMC was obtained from bone marrow aspirates using an automated blood separator. The BMC was then seeded onto β-TCP granules pre-adsorbed with a suboptimal-dose (minimum concentration to induce bone formation at 2 weeks in mice) of recombinant human (rh) BMP-2. These specimens were transplanted subcutaneously to the dorsal skin of immunodeficient-mice and the induction of ectopic bone formation was assessed 2 and 4 weeks post-transplantation. Transplantations of five other groups [PB, PRP, platelet-poor plasma (PPP), bone marrow aspirate (BM), and BM-PPP] were employed as experimental controls. Then, to clarify the effects on vertical bone augmentation, specimens from the six groups were transplanted for on-lay placement on the craniums of mice. The results indicated that BMC, which contained an approximately 2.5-fold increase in the number of MNCs compared to PRP, could accelerate ectopic bone formation until 2 weeks post-transplantation. On the cranium, the BMC group promoted bone augmentation with a suboptimal-dose of rhBMP-2 compared to other groups. Particularly in the BMC specimens harvested at 4 weeks, we observed newly formed bone surrounding the TCP granules at sites far from the calvarial bone. In conclusion, the addition of BMC could reduce the amount of rhBMP-2 by one-half via its synergistic effect on early-phase osteoinduction. We propose here that BMC transplantation
Clinical implementation and evaluation of the Acuros dose calculation algorithm.
Yan, Chenyu; Combine, Anthony G; Bednarz, Greg; Lalonde, Ronald J; Hu, Bin; Dickens, Kathy; Wynn, Raymond; Pavord, Daniel C; Saiful Huq, M
2017-09-01
The main aim of this study is to validate the Acuros XB dose calculation algorithm for a Varian Clinac iX linac in our clinics, and subsequently compare it with the wildely used AAA algorithm. The source models for both Acuros XB and AAA were configured by importing the same measured beam data into Eclipse treatment planning system. Both algorithms were validated by comparing calculated dose with measured dose on a homogeneous water phantom for field sizes ranging from 6 cm × 6 cm to 40 cm × 40 cm. Central axis and off-axis points with different depths were chosen for the comparison. In addition, the accuracy of Acuros was evaluated for wedge fields with wedge angles from 15 to 60°. Similarly, variable field sizes for an inhomogeneous phantom were chosen to validate the Acuros algorithm. In addition, doses calculated by Acuros and AAA at the center of lung equivalent tissue from three different VMAT plans were compared to the ion chamber measured doses in QUASAR phantom, and the calculated dose distributions by the two algorithms and their differences on patients were compared. Computation time on VMAT plans was also evaluated for Acuros and AAA. Differences between dose-to-water (calculated by AAA and Acuros XB) and dose-to-medium (calculated by Acuros XB) on patient plans were compared and evaluated. For open 6 MV photon beams on the homogeneous water phantom, both Acuros XB and AAA calculations were within 1% of measurements. For 23 MV photon beams, the calculated doses were within 1.5% of measured doses for Acuros XB and 2% for AAA. Testing on the inhomogeneous phantom demonstrated that AAA overestimated doses by up to 8.96% at a point close to lung/solid water interface, while Acuros XB reduced that to 1.64%. The test on QUASAR phantom showed that Acuros achieved better agreement in lung equivalent tissue while AAA underestimated dose for all VMAT plans by up to 2.7%. Acuros XB computation time was about three times faster than AAA for VMAT plans, and
Three-dimensional electron-beam dose calculations
International Nuclear Information System (INIS)
Shiu, A.S.
1988-01-01
The MDAH pencil-beam algorithm developed by Hogstrom et al (1981) has been widely used in clinics for electron-beam dose calculations for radiotherapy treatment planning. The primary objective of this research was to address several deficiencies of that algorithm and to develop an enhanced version. Two enhancements were incorporated into the pencil-beam algorithm; one models fluence rather than planar fluence, and the other models the bremsstrahlung dose using measured beam data. Comparisons of the resulting calculated dose distributions with measured dose distributions for several test phantoms have been made. From these results it is concluded (1) that the fluence-based algorithm is more accurate to use for the dose calculation in an inhomogeneous slab phantom, and (2) the fluence-based calculation provides only a limited improvement to the accuracy the calculated dose in the region just downstream of the lateral edge of an inhomogeneity. A pencil-beam redefinition model was developed for the calculation of electron-beam dose distributions in three dimensions
Fluence-convolution broad-beam (FCBB) dose calculation
Energy Technology Data Exchange (ETDEWEB)
Lu Weiguo; Chen Mingli, E-mail: wlu@tomotherapy.co [TomoTherapy Inc., 1240 Deming Way, Madison, WI 53717 (United States)
2010-12-07
IMRT optimization requires a fast yet relatively accurate algorithm to calculate the iteration dose with small memory demand. In this paper, we present a dose calculation algorithm that approaches these goals. By decomposing the infinitesimal pencil beam (IPB) kernel into the central axis (CAX) component and lateral spread function (LSF) and taking the beam's eye view (BEV), we established a non-voxel and non-beamlet-based dose calculation formula. Both LSF and CAX are determined by a commissioning procedure using the collapsed-cone convolution/superposition (CCCS) method as the standard dose engine. The proposed dose calculation involves a 2D convolution of a fluence map with LSF followed by ray tracing based on the CAX lookup table with radiological distance and divergence correction, resulting in complexity of O(N{sup 3}) both spatially and temporally. This simple algorithm is orders of magnitude faster than the CCCS method. Without pre-calculation of beamlets, its implementation is also orders of magnitude smaller than the conventional voxel-based beamlet-superposition (VBS) approach. We compared the presented algorithm with the CCCS method using simulated and clinical cases. The agreement was generally within 3% for a homogeneous phantom and 5% for heterogeneous and clinical cases. Combined with the 'adaptive full dose correction', the algorithm is well suitable for calculating the iteration dose during IMRT optimization.
Calculation of committed dose equivalent from intake of tritiated water
International Nuclear Information System (INIS)
Law, D.V.
1978-08-01
A new computerized method of calculating the committed dose equivalent from the intake of tritiated water at Harwell is described in this report. The computer program has been designed to deal with a variety of intake patterns and urine sampling schemes, as well as to produce committed dose equivalents corresponding to any periods for which individual monitoring for external radiation is undertaken. Details of retrospective doses are added semi-automatically to the Radiation Dose Records and committed dose equivalents are retained on a separate file. (author)
Thermal neutron dose calculation in synovium membrane for BNCS
International Nuclear Information System (INIS)
Abdalla, Khalid; Naqvi, A.A.; Maalej, N.; El-Shahat, B.
2006-01-01
A D(d,n) reaction based setup has been optimized for Boron Neutron Capture Synovectomy (BNCS). The polyethylene moderator and graphite reflector sizes were optimized to deliver the highest ratio of thermal to fast neutron yield. The neutron dose was calculated at various depths in a knee phantom loaded with boron to determine therapeutic ratios of synovium dose/skin dose and synovium dose/bone dose. Normalized to same boron loading in synovium, the values of the therapeutic ratios obtained in the present study are 12-30 times higher than the published values. (author)
Sequential changes in bone marrow architecture during continuous low dose gamma irradiation
International Nuclear Information System (INIS)
Seed, T.M.; Chubb, G.T.; Tolle, D.V.
1981-01-01
Beagles continuously exposed to low daily doses (10 R) of whole-body 60Co gamma-radiation are prone to develop either early occurring aplastic anemia or late occurring myeloproliferative disorders (Seed et al., 1977). In this study, we have examined by a combination of light microscopy and scanning and transmission electron microscopy the sequential changes in the morphology of biopsied rib bone marrow of continuously irradiated dogs that developed either aplastic anemia, myelofibrosis, or myelogenous leukemia. Characteristic modification of key elements of marrow architecture have been observed during preclinical and clinical phases of these hemopathological conditions. The more prominent of these changes include the following. (i) In developing aplastic anemia: severe vascular sinus and parenchymal cord compression, and focally degenerate endosteal surfaces. (ii) In developing myelofibrosis: hyperplasia of endosteal and reticular stomal elements. (iii) In developing leukemia: hypertrophy of reticular and endothelial elements in the initial restructuring of the stromal matrix and the subsequent aberrant hemopoietic repopulation of the initially depleted stromal matrix. These architectural changes during preclinical phases appear to be related to the pathological progression to each of the radiation-induced hemopathological end points
Methodology of dose calculation for the SRS SAR
International Nuclear Information System (INIS)
Price, J.B.
1991-07-01
The Savannah River Site (SRS) Safety Analysis Report (SAR) covering K reactor operation assesses a spectrum of design basis accidents. The assessment includes estimation of the dose consequences from the analyzed accidents. This report discusses the methodology used to perform the dose analysis reported in the SAR and also includes the quantified doses. Doses resulting from postulated design basis reactor accidents in Chapter 15 of the SAR are discussed, as well as an accident in which three percent of the fuel melts. Doses are reported for both atmospheric and aqueous releases. The methodology used to calculate doses from these accidents as reported in the SAR is consistent with NRC guidelines and industry standards. The doses from the design basis accidents for the SRS reactors are below the limits set for commercial reactors by the NRC and also meet industry criteria. A summary of doses for various postulated accidents is provided
International Nuclear Information System (INIS)
Thieke, Christian; Nill, Simeon; Oelfke, Uwe; Bortfeld, Thomas
2002-01-01
In inverse planning for intensity-modulated radiotherapy, the dose calculation is a crucial element limiting both the maximum achievable plan quality and the speed of the optimization process. One way to integrate accurate dose calculation algorithms into inverse planning is to precalculate the dose contribution of each beam element to each voxel for unit fluence. These precalculated values are stored in a big dose calculation matrix. Then the dose calculation during the iterative optimization process consists merely of matrix look-up and multiplication with the actual fluence values. However, because the dose calculation matrix can become very large, this ansatz requires a lot of computer memory and is still very time consuming, making it not practical for clinical routine without further modifications. In this work we present a new method to significantly reduce the number of entries in the dose calculation matrix. The method utilizes the fact that a photon pencil beam has a rapid radial dose falloff, and has very small dose values for the most part. In this low-dose part of the pencil beam, the dose contribution to a voxel is only integrated into the dose calculation matrix with a certain probability. Normalization with the reciprocal of this probability preserves the total energy, even though many matrix elements are omitted. Three probability distributions were tested to find the most accurate one for a given memory size. The sampling method is compared with the use of a fully filled matrix and with the well-known method of just cutting off the pencil beam at a certain lateral distance. A clinical example of a head and neck case is presented. It turns out that a sampled dose calculation matrix with only 1/3 of the entries of the fully filled matrix does not sacrifice the quality of the resulting plans, whereby the cutoff method results in a suboptimal treatment plan
Current evaluation of dose rate calculation - analytical method
International Nuclear Information System (INIS)
Tello, Marcos; Vilhena, Marco Tulio
1996-01-01
The accuracy of the dose calculations based on pencil beam formulas such as Fokker-Plank equations and Fermi equations for charged particle transport are studied and a methodology to solve the Boltzmann transport equation is suggested
Dose Rate Calculations for Rotary Mode Core Sampling Exhauster
Foust, D J
2000-01-01
This document provides the calculated estimated dose rates for three external locations on the Rotary Mode Core Sampling (RMCS) exhauster HEPA filter housing, per the request of Characterization Field Engineering.
Dose Rate Calculations for Rotary Mode Core Sampling Exhauster
International Nuclear Information System (INIS)
FOUST, D.J.
2000-01-01
This document provides the calculated estimated dose rates for three external locations on the Rotary Mode Core Sampling (RMCS) exhauster HEPA filter housing, per the request of Characterization Field Engineering
Educational audit on drug dose calculation learning in a Tanzanian ...
African Journals Online (AJOL)
Background: Patient safety is a key concern for nurses; ability to calculate drug ... Specific objectives were to assess learning from targeted teaching, to identify problem areas in perfor- .... this could result in reduced risk of drug dose error in.
Application of a sitting MIRD phantom for effective dose calculations
International Nuclear Information System (INIS)
Olsher, R. H.; Van Riper, K. A.
2005-01-01
In typical realistic scenarios, dose factors due to 60 Co contaminated steel, used in consumer products, cannot be approximated by standard exposure geometries. It is then necessary to calculate the effective dose using an appropriate anthropomorphic phantom. MCNP calculations were performed using a MIRD human model in two settings. In the first, a male office worker is sitting in a chair containing contaminated steel, surrounded by contaminated furniture. In the second, a male driver is seated inside an automobile, the steel of which is uniformly contaminated. To accurately calculate the dose to lower body organs, especially the gonads, it was essential to modify the MIRD model to simulate two sitting postures: chair and driving position. The phantom modifications are described, and the results of the calculations are presented. In the case of the automobile scenarios, results are compared to those obtained using an isotropic fluence-to-dose conversion function. (authors)
International Nuclear Information System (INIS)
Sharma, Subhash; Ott, Joseph; Williams, Jamone; Dickow, Danny
2011-01-01
Monte Carlo dose calculation algorithms have the potential for greater accuracy than traditional model-based algorithms. This enhanced accuracy is particularly evident in regions of lateral scatter disequilibrium, which can develop during treatments incorporating small field sizes and low-density tissue. A heterogeneous slab phantom was used to evaluate the accuracy of several commercially available dose calculation algorithms, including Monte Carlo dose calculation for CyberKnife, Analytical Anisotropic Algorithm and Pencil Beam convolution for the Eclipse planning system, and convolution-superposition for the Xio planning system. The phantom accommodated slabs of varying density; comparisons between planned and measured dose distributions were accomplished with radiochromic film. The Monte Carlo algorithm provided the most accurate comparison between planned and measured dose distributions. In each phantom irradiation, the Monte Carlo predictions resulted in gamma analysis comparisons >97%, using acceptance criteria of 3% dose and 3-mm distance to agreement. In general, the gamma analysis comparisons for the other algorithms were <95%. The Monte Carlo dose calculation algorithm for CyberKnife provides more accurate dose distribution calculations in regions of lateral electron disequilibrium than commercially available model-based algorithms. This is primarily because of the ability of Monte Carlo algorithms to implicitly account for tissue heterogeneities, density scaling functions; and/or effective depth correction factors are not required.
Testing of the analytical anisotropic algorithm for photon dose calculation
International Nuclear Information System (INIS)
Esch, Ann van; Tillikainen, Laura; Pyykkonen, Jukka; Tenhunen, Mikko; Helminen, Hannu; Siljamaeki, Sami; Alakuijala, Jyrki; Paiusco, Marta; Iori, Mauro; Huyskens, Dominique P.
2006-01-01
The analytical anisotropic algorithm (AAA) was implemented in the Eclipse (Varian Medical Systems) treatment planning system to replace the single pencil beam (SPB) algorithm for the calculation of dose distributions for photon beams. AAA was developed to improve the dose calculation accuracy, especially in heterogeneous media. The total dose deposition is calculated as the superposition of the dose deposited by two photon sources (primary and secondary) and by an electron contamination source. The photon dose is calculated as a three-dimensional convolution of Monte-Carlo precalculated scatter kernels, scaled according to the electron density matrix. For the configuration of AAA, an optimization algorithm determines the parameters characterizing the multiple source model by optimizing the agreement between the calculated and measured depth dose curves and profiles for the basic beam data. We have combined the acceptance tests obtained in three different departments for 6, 15, and 18 MV photon beams. The accuracy of AAA was tested for different field sizes (symmetric and asymmetric) for open fields, wedged fields, and static and dynamic multileaf collimation fields. Depth dose behavior at different source-to-phantom distances was investigated. Measurements were performed on homogeneous, water equivalent phantoms, on simple phantoms containing cork inhomogeneities, and on the thorax of an anthropomorphic phantom. Comparisons were made among measurements, AAA, and SPB calculations. The optimization procedure for the configuration of the algorithm was successful in reproducing the basic beam data with an overall accuracy of 3%, 1 mm in the build-up region, and 1%, 1 mm elsewhere. Testing of the algorithm in more clinical setups showed comparable results for depth dose curves, profiles, and monitor units of symmetric open and wedged beams below d max . The electron contamination model was found to be suboptimal to model the dose around d max , especially for physical
International Nuclear Information System (INIS)
Kim, T.H.; Kersey, J.H.; Khan, F.M.; Sewchand, W.; Ramsey, N.; Krivit, W.; Coccia, P.; Nesbit, M.E.; Levitt, S.H.
1979-01-01
Six patients with aplastic anemia underwent bone marrow transplantation following conditioning with high dose cyclophosphamide and single dose total lymphoid irradiation with 750 rad, 26 rad/min at the midplane of the patient. They all received bone marrow from human leukocyte antigens/mixed lymphocyte culture (HLA/MLC) matched siblings. Five of 6 patients were alive without complications at 12, 11, 7, 4 and 4 months respectively. The remaining patient died from sepis which he had prior to transplantation. There were no graft rejection, graft-vs-Host Disease (GVHD) or interstitial pneumonitis among these patients. The procedure was well tolerated with minimal side effects. The results will be compared with those of groups whose bone marrow was previously transplanted with different immunosuppressive methods
Manual method for dose calculation in gynecologic brachytherapy
International Nuclear Information System (INIS)
Vianello, Elizabeth A.; Almeida, Carlos E. de; Biaggio, Maria F. de
1998-01-01
This paper describes a manual method for dose calculation in brachytherapy of gynecological tumors, which allows the calculation of the doses at any plane or point of clinical interest. This method uses basic principles of vectorial algebra and the simulating orthogonal films taken from the patient with the applicators and dummy sources in place. The results obtained with method were compared with the values calculated with the values calculated with the treatment planning system model Theraplan and the agreement was better than 5% in most cases. The critical points associated with the final accuracy of the proposed method is related to the quality of the image and the appropriate selection of the magnification factors. This method is strongly recommended to the radiation oncology centers where are no treatment planning systems available and the dose calculations are manually done. (author)
Calculating gamma dose factors for hot particle exposures
International Nuclear Information System (INIS)
Murphy, P.
1990-01-01
For hot particle exposures to the skin, the beta component of radiation delivers the majority of the dose. However, in order to fully demonstrate regulatory compliance, licenses must ordinarily provide reasonable bases for assuming that both the gamma component of the skin dose and the whole body doses are negligible. While beta dose factors are commonly available in the literature, gamma dose factors are not. This paper describes in detail a method by which gamma skin dose factors may be calculated using the Specific Gamma-ray Constant, even if the particle is not located directly on the skin. Two common hot particle exposure geometries are considered: first, a single square centimeter of skin lying at density thickness of 7 mg/cm 2 and then at 1000 mg/cm 2 . A table provides example gamma dose factors for a number of isotopes encountered at power reactors
Dose calculations algorithm for narrow heavy charged-particle beams
Energy Technology Data Exchange (ETDEWEB)
Barna, E A; Kappas, C [Department of Medical Physics, School of Medicine, University of Patras (Greece); Scarlat, F [National Institute for Laser and Plasma Physics, Bucharest (Romania)
1999-12-31
The dose distributional advantages of the heavy charged-particles can be fully exploited by using very efficient and accurate dose calculation algorithms, which can generate optimal three-dimensional scanning patterns. An inverse therapy planning algorithm for dynamically scanned, narrow heavy charged-particle beams is presented in this paper. The irradiation `start point` is defined at the distal end of the target volume, right-down, in a beam`s eye view. The peak-dose of the first elementary beam is set to be equal to the prescribed dose in the target volume, and is defined as the reference dose. The weighting factor of any Bragg-peak is determined by the residual dose at the point of irradiation, calculated as the difference between the reference dose and the cumulative dose delivered at that point of irradiation by all the previous Bragg-peaks. The final pattern consists of the weighted Bragg-peaks irradiation density. Dose distributions were computed using two different scanning steps equal to 0.5 mm, and 1 mm respectively. Very accurate and precise localized dose distributions, conform to the target volume, were obtained. (authors) 6 refs., 3 figs.
Dose-Response Calculator for ArcGIS
Hanser, Steven E.; Aldridge, Cameron L.; Leu, Matthias; Nielsen, Scott E.
2011-01-01
The Dose-Response Calculator for ArcGIS is a tool that extends the Environmental Systems Research Institute (ESRI) ArcGIS 10 Desktop application to aid with the visualization of relationships between two raster GIS datasets. A dose-response curve is a line graph commonly used in medical research to examine the effects of different dosage rates of a drug or chemical (for example, carcinogen) on an outcome of interest (for example, cell mutations) (Russell and others, 1982). Dose-response curves have recently been used in ecological studies to examine the influence of an explanatory dose variable (for example, percentage of habitat cover, distance to disturbance) on a predicted response (for example, survival, probability of occurrence, abundance) (Aldridge and others, 2008). These dose curves have been created by calculating the predicted response value from a statistical model at different levels of the explanatory dose variable while holding values of other explanatory variables constant. Curves (plots) developed using the Dose-Response Calculator overcome the need to hold variables constant by using values extracted from the predicted response surface of a spatially explicit statistical model fit in a GIS, which include the variation of all explanatory variables, to visualize the univariate response to the dose variable. Application of the Dose-Response Calculator can be extended beyond the assessment of statistical model predictions and may be used to visualize the relationship between any two raster GIS datasets (see example in tool instructions). This tool generates tabular data for use in further exploration of dose-response relationships and a graph of the dose-response curve.
Motion-encoded dose calculation through fluence/sinogram modification
International Nuclear Information System (INIS)
Lu, Weiguo; Olivera, Gustavo H.; Mackie, Thomas R.
2005-01-01
Conventional radiotherapy treatment planning systems rely on a static computed tomography (CT) image for planning and evaluation. Intra/inter-fraction patient motions may result in significant differences between the planned and the delivered dose. In this paper, we develop a method to incorporate the knowledge of intra/inter-fraction patient motion directly into the dose calculation. By decomposing the motion into a parallel (to beam direction) component and perpendicular (to beam direction) component, we show that the motion effects can be accounted for by simply modifying the fluence distribution (sinogram). After such modification, dose calculation is the same as those based on a static planning image. This method is superior to the 'dose-convolution' method because it is not based on 'shift invariant' assumption. Therefore, it deals with material heterogeneity and surface curvature very well. We test our method using extensive simulations, which include four phantoms, four motion patterns, and three plan beams. We compare our method with the 'dose-convolution' and the 'stochastic simulation' methods (gold standard). As for the homogeneous flat surface phantom, our method has similar accuracy as the 'dose-convolution' method. As for all other phantoms, our method outperforms the 'dose-convolution'. The maximum motion encoded dose calculation error using our method is within 4% of the gold standard. It is shown that a treatment planning system that is based on 'motion-encoded dose calculation' can incorporate random and systematic motion errors in a very simple fashion. Under this approximation, in principle, a planning target volume definition is not required, since it already accounts for the intra/inter-fraction motion variations and it automatically optimizes the cumulative dose rather than the single fraction dose
International Nuclear Information System (INIS)
Kazama, Toshiki; Swanston, Nancy; Podoloff, Donald A.; Macapinlac, Homer A.
2005-01-01
Granulocyte or granulocyte-macrophage colony stimulating factor (CSF), usually used in conjunction with chemotherapy, may interfere with the 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) reading. The purpose of this study is to evaluate the effects of CSF, conventional-or high-dose chemotherapy on bone marrow FDG uptake. Two hundred and forty-one FDG PET scans obtained in 163 patients with lymphoma and no pathologically and radiologically proven bone marrow involvement were analyzed. The standardized uptake value (SUV) of each patient's spine was measured. Among patients with no recent history of CSF use, the average SUV in 36 patients with no history of chemotherapy was 1.60±0.34, that in 49 patients with a history of conventional-dose chemotherapy was 1.37±0.32, and that in 12 patients with a history of high-dose chemotherapy was 1.26±0.25 (P=0.008 and 0.002, respectively by Mann-Whitney U test). In 80 patients treated with conventional-dose chemotherapy and CSF, the average SUV after discontinuation of CSF was as follows: 0-7 days, 2.37±1.19; 8-14 days: 2.04±0.67; 15-21 days: 1.87±0.52; 22-30 days: 1.59±0.18; 31-90 days: 1.54±0.36. In 45 patients treated with high-dose chemotherapy and CSF, no significant increase in bone marrow uptake was seen in most of them. Bone marrow FDG uptake may be increased by CSF treatment and may be decreased by chemotherapy. In patients treated with conventional-dose chemotherapy and CSF, increased marrow uptake will return to the pretreatment value approximately 1 month after discontinuation of CSF. (orig.)
PLUTONIUM/HIGH-LEVEL VITRIFIED WASTE BDBE DOSE CALCULATION
Energy Technology Data Exchange (ETDEWEB)
J.A. Ziegler
2000-11-20
The purpose of this calculation is to provide a dose consequence analysis of high-level waste (HLW) consisting of plutonium immobilized in vitrified HLW to be handled at the proposed Monitored Geologic Repository at Yucca Mountain for a beyond design basis event (BDBE) under expected conditions using best estimate values for each calculation parameter. In addition to the dose calculation, a plutonium respirable particle size for dose calculation use is derived. The current concept for this waste form is plutonium disks enclosed in cans immobilized in canisters of vitrified HLW (i.e., glass). The plutonium inventory at risk used for this calculation is selected from Plutonium Immobilization Project Input for Yucca Mountain Total Systems Performance Assessment (Shaw 1999). The BDBE examined in this calculation is a nonmechanistic initiating event and the sequence of events that follow to cause a radiological release. This analysis will provide the radiological releases and dose consequences for a postulated BDBE. Results may be considered in other analyses to determine or modify the safety classification and quality assurance level of repository structures, systems, and components. This calculation uses best available technical information because the BDBE frequency is very low (i.e., less than 1.0E-6 events/year) and is not required for License Application for the Monitored Geologic Repository. The results of this calculation will not be used as part of a licensing or design basis.
Calculation method for gamma dose rates from Gaussian puffs
Energy Technology Data Exchange (ETDEWEB)
Thykier-Nielsen, S; Deme, S; Lang, E
1995-06-01
The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of E{sub {gamma}}, {sigma}{sub y}, the asymmetry factor - {sigma}{sub y}/{sigma}{sub z}, the height of puff center - H and the distance from puff center R{sub xy}. To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs.
Calculation method for gamma dose rates from Gaussian puffs
International Nuclear Information System (INIS)
Thykier-Nielsen, S.; Deme, S.; Lang, E.
1995-06-01
The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of E γ , σ y , the asymmetry factor - σ y /σ z , the height of puff center - H and the distance from puff center R xy . To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs
The calculation of dose rates from rectangular sources
International Nuclear Information System (INIS)
Hartley, B.M.
1998-01-01
A common problem in radiation protection is the calculation of dose rates from extended sources and irregular shapes. Dose rates are proportional to the solid angle subtended by the source at the point of measurement. Simple methods of calculating solid angles would assist in estimating dose rates from large area sources and therefore improve predictive dose estimates when planning work near such sources. The estimation of dose rates is of particular interest to producers of radioactive ores but other users of bulk radioactive materials may have similar interest. The use of spherical trigonometry can assist in determination of solid angles and a simple equation is derived here for the determination of the dose at any distance from a rectangular surface. The solid angle subtended by complex shapes can be determined by modelling the area as a patchwork of rectangular areas and summing the solid angles from each rectangle. The dose rates from bags of thorium bearing ores is of particular interest in Western Australia and measured dose rates from bags and containers of monazite are compared with theoretical estimates based on calculations of solid angle. The agreement is fair but more detailed measurements would be needed to confirm the agreement with theory. (author)
Calculation of the dose caused by internal radiation
Energy Technology Data Exchange (ETDEWEB)
NONE
2000-07-01
For the purposes of monitoring radiation exposure it is necessary to determine or to estimate the dose caused by both external and internal radiation. When comparing the value of exposure to the dose limits, account must be taken of the total dose incurred from different sources. This guide explains how to calculate the committed effective dose caused by internal radiation and gives the conversion factors required for the calculation. Application of the maximum values for radiation exposure is dealt with in ST guide 7.2, which also sets out the definitions of the quantities and concepts most commonly used in the monitoring of radiation exposure. The monitoring of exposure and recording of doses are dealt with in ST Guides 7.1 and 7.4.
Calculation method for gamma-dose rates from spherical puffs
International Nuclear Information System (INIS)
Thykier-Nielsen, S.; Deme, S.; Lang, E.
1993-05-01
The Lagrangian puff-models are widely used for calculation of the dispersion of atmospheric releases. Basic output from such models are concentrations of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on semi-infinite cloud model. This method is however only applicable for points far away from the release point. The exact calculation of the cloud dose using the volume integral requires significant computer time. The volume integral for the gamma dose could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor due to the fact that the same correction factors are used for all isotopes. The authors describe a more elaborate correction method. This method uses precalculated values of the gamma-dose rate as a function of the puff dispersion parameter (δ p ) and the distance from the puff centre for four energy groups. The release of energy for each radionuclide in each energy group has been calculated and tabulated. Based on these tables and a suitable interpolation procedure the calculation of gamma doses takes very short time and is almost independent of the number of radionuclides. (au) (7 tabs., 7 ills., 12 refs.)
Time improvement of photoelectric effect calculation for absorbed dose estimation
International Nuclear Information System (INIS)
Massa, J M; Wainschenker, R S; Doorn, J H; Caselli, E E
2007-01-01
Ionizing radiation therapy is a very useful tool in cancer treatment. It is very important to determine absorbed dose in human tissue to accomplish an effective treatment. A mathematical model based on affected areas is the most suitable tool to estimate the absorbed dose. Lately, Monte Carlo based techniques have become the most reliable, but they are time expensive. Absorbed dose calculating programs using different strategies have to choose between estimation quality and calculating time. This paper describes an optimized method for the photoelectron polar angle calculation in photoelectric effect, which is significant to estimate deposited energy in human tissue. In the case studies, time cost reduction nearly reached 86%, meaning that the time needed to do the calculation is approximately 1/7 th of the non optimized approach. This has been done keeping precision invariant
International Nuclear Information System (INIS)
Khailov, A.M.; Ivannikov, A.I.; Skvortsov, V.G.; Stepanenko, V.F.; Orlenko, S.P.; Flood, A.B.; Williams, B.B.; Swartz, H.M.
2015-01-01
Absorbed doses to fingernails and organs were calculated for a set of homogenous external gamma-ray irradiation geometries in air. The doses were obtained by stochastic modeling of the ionizing particle transport (Monte Carlo method) for a mathematical human phantom with arms and hands placed loosely along the sides of the body. The resulting dose conversion factors for absorbed doses in fingernails can be used to assess the dose distribution and magnitude in practical dose reconstruction problems. For purposes of estimating dose in a large population exposed to radiation in order to triage people for treatment of acute radiation syndrome, the calculated data for a range of energies having a width of from 0.05 to 3.5 MeV were used to convert absorbed doses in fingernails to corresponding doses in organs and the whole body as well as the effective dose. Doses were assessed based on assumed rates of radioactive fallout at different time periods following a nuclear explosion. - Highlights: • Elemental composition and density of nails were determined. • MIRD-type mathematical human phantom with arms and hands was created. • Organ doses and doses to nails were calculated for external photon exposure in air. • Effective dose and nail doses values are close for rotational and soil surface exposures.
International Nuclear Information System (INIS)
Spiers, F.W.; Whitwell, J.R.; Beddoe, A.H.
1978-01-01
The method of calculating dose factors for the haemopoietic marrow and endosteal tissues in human trabecular bone, used by Whitwell and Spiers for volume-seeking radionuclides, has been developed for the case of radionuclides which are deposited as very thin layers on bone surfaces. The Monte Carlo method is again used, but modifications to the computer program are made to allow for a surface rather than a volume source of particle emission. The principal change is the introduction of a surface-orientation factor which is shown to have a value of approximately 2, varying slightly with bone structure. Results are given for β-emitting radionuclides ranging from 171 Tm(anti Esub(β) = 0.025 MeV) to 90 Y(anti Esub(β) = 0.93 MeV), and also for the α-emitter 239 Pu. It is shown that where the particle ranges are short compared with the dimensions of the bone structures the dose factors for the surface seekers are much greater than those for the volume seekers. For long range particles the dose factors for surface- and volume-seeking radionuclides converge. Comparisons are given relating the dose factors calculated in this paper on the basis of measured bone structures to those of other workers based on single plane geometry. (author)
Measurement of MC5 antibody distribution in blood and bone marrow
International Nuclear Information System (INIS)
Johnson, T.K.; Gonzales, R.; Kasliwal, R.; Lear, J.; Feyerabend, A.; Ceriani, R.; Bunn, P.
1990-01-01
PURPOSE: Bone marrow is most often the dose-limiting organ in radioimmunotherapy. Controversy exists over optimal methods of estimating dose exposure to bone marrow. The purpose of this paper is to compare bone marrow activity from serial blood samples versus bone marrow biopsy specimens as measures of dose exposure to bone marrow. Peripheral blood samples and bone marrow biopsy specimens were obtained at 48 and 168 hours after infusion from 12 female patients infused with iodine-131-labeled MC5 antibody. The percentage of bone marrow in each biopsy specimen was assumed to be equivalent to the percentage of active bone marrow estimated to be in the pelvis. Activity present in the bone marrow as calculated with use of the estimated bone marrow mass for an adult female and then compared with the peripheral blood activity
Computer code for calculating personnel doses due to tritium exposures
International Nuclear Information System (INIS)
Graham, C.L.; Parlagreco, J.R.
1977-01-01
This report describes a computer code written in LLL modified Fortran IV that can be used on a CDC 7600 for calculating personnel doses due to internal exposures to tritium. The code is capable of handling various exposure situations and is also capable of detecting a large variety of data input errors that would lead to errors in the dose assessment. The critical organ is the body water
Beta and gamma dose calculations for PWR and BWR containments
International Nuclear Information System (INIS)
King, D.B.
1989-07-01
Analyses of gamma and beta dose in selected regions in PWR and BWR containment buildings have been performed for a range of fission product releases from selected severe accidents. The objective of this study was to determine the radiation dose that safety-related equipment could experience during the selected severe accident sequences. The resulting dose calculations demonstrate the extent to which design basis accident qualified equipment could also be qualified for the severe accident environments. Surry was chosen as the representative PWR plant while Peach Bottom was selected to represent BWRs. Battelle Columbus Laboratory performed the source term release analyses. The AB epsilon scenario (an intermediate to large LOCA with failure to recover onsite or offsite electrical power) was selected as the base case Surry accident, and the AE scenario (a large break LOCA with one initiating event and a combination of failures in two emergency cooling systems) was selected as the base case Peach Bottom accident. Radionuclide release was bounded for both scenarios by including spray operation and arrested sequences as variations of the base scenarios. Sandia National Laboratories used the source terms to calculate dose to selected containment regions. Scenarios with sprays operational resulted in a total dose comparable to that (2.20 x 10 8 rads) used in current equipment qualification testing. The base case scenarios resulted in some calculated doses roughly an order of magnitude above the current 2.20 x 10 8 rad equipment qualification test region. 8 refs., 23 figs., 12 tabs
Enamel dose calculation by electron paramagnetic resonance spectral simulation technique
International Nuclear Information System (INIS)
Dong Guofu; Cong Jianbo; Guo Linchao; Ning Jing; Xian Hong; Wang Changzhen; Wu Ke
2011-01-01
Objective: To optimize the enamel electron paramagnetic resonance (EPR) spectral processing by using the EPR spectral simulation method to improve the accuracy of enamel EPR dosimetry and reduce artificial error. Methods: The multi-component superimposed EPR powder spectral simulation software was developed to simulate EPR spectrum models of the background signal (BS) and the radiation- induced signal (RS) of irradiated enamel respectively. RS was extracted from the multi-component superimposed spectrum of irradiated enamel and its amplitude was calculated. The dose-response curve was then established for calculating the doses of a group of enamel samples. The result of estimated dose was compared with that calculated by traditional method. Results: BS was simulated as a powder spectrum of gaussian line shape with the following spectrum parameters: g=2.00 35 and Hpp=0.65-1.1 mT, RS signal was also simulated as a powder spectrum but with axi-symmetric spectrum characteristics. The spectrum parameters of RS were: g ⊥ =2.0018, g ‖ =1.9965, Hpp=0.335-0.4 mT. The amplitude of RS had a linear response to radiation dose with the regression equation as y=240.74x + 76 724 (R 2 =0.9947). The expectation of relative error of dose estimation was 0.13. Conclusions: EPR simulation method has improved somehow the accuracy and reliability of enamel EPR dose estimation. (authors)
Reducing dose calculation time for accurate iterative IMRT planning
International Nuclear Information System (INIS)
Siebers, Jeffrey V.; Lauterbach, Marc; Tong, Shidong; Wu Qiuwen; Mohan, Radhe
2002-01-01
A time-consuming component of IMRT optimization is the dose computation required in each iteration for the evaluation of the objective function. Accurate superposition/convolution (SC) and Monte Carlo (MC) dose calculations are currently considered too time-consuming for iterative IMRT dose calculation. Thus, fast, but less accurate algorithms such as pencil beam (PB) algorithms are typically used in most current IMRT systems. This paper describes two hybrid methods that utilize the speed of fast PB algorithms yet achieve the accuracy of optimizing based upon SC algorithms via the application of dose correction matrices. In one method, the ratio method, an infrequently computed voxel-by-voxel dose ratio matrix (R=D SC /D PB ) is applied for each beam to the dose distributions calculated with the PB method during the optimization. That is, D PB xR is used for the dose calculation during the optimization. The optimization proceeds until both the IMRT beam intensities and the dose correction ratio matrix converge. In the second method, the correction method, a periodically computed voxel-by-voxel correction matrix for each beam, defined to be the difference between the SC and PB dose computations, is used to correct PB dose distributions. To validate the methods, IMRT treatment plans developed with the hybrid methods are compared with those obtained when the SC algorithm is used for all optimization iterations and with those obtained when PB-based optimization is followed by SC-based optimization. In the 12 patient cases studied, no clinically significant differences exist in the final treatment plans developed with each of the dose computation methodologies. However, the number of time-consuming SC iterations is reduced from 6-32 for pure SC optimization to four or less for the ratio matrix method and five or less for the correction method. Because the PB algorithm is faster at computing dose, this reduces the inverse planning optimization time for our implementation
Dose calculation of X-ray in medium
International Nuclear Information System (INIS)
Liu Yanmei; Xue Dingyu; Xu Xinhe; Chen Zhen; Dong Zaili
2006-01-01
The photon transportation in radiotherapy is studied based on Monte Carlo method. The dose calculation based on the MC simulation package DPM has been carried out, and the results have been visualized using MEX technology of Matlab. The dose results of X-ray in homogeneity and inhomogeneity medium have been compared with experimental data and those of other MC simulation package, and these results all agree. The calculation method we proposed has the advantage of high speed and good accuracy, therefore, is applicable in practice. (authors)
Monte Carlo dose calculation algorithm on a distributed system
International Nuclear Information System (INIS)
Chauvie, Stephane; Dominoni, Matteo; Marini, Piergiorgio; Stasi, Michele; Pia, Maria Grazia; Scielzo, Giuseppe
2003-01-01
The main goal of modern radiotherapy, such as 3D conformal radiotherapy and intensity-modulated radiotherapy is to deliver a high dose to the target volume sparing the surrounding healthy tissue. The accuracy of dose calculation in a treatment planning system is therefore a critical issue. Among many algorithms developed over the last years, those based on Monte Carlo proven to be very promising in terms of accuracy. The most severe obstacle in application to clinical practice is the high time necessary for calculations. We have studied a high performance network of Personal Computer as a realistic alternative to a high-costs dedicated parallel hardware to be used routinely as instruments of evaluation of treatment plans. We set-up a Beowulf Cluster, configured with 4 nodes connected with low-cost network and installed MC code Geant4 to describe our irradiation facility. The MC, once parallelised, was run on the Beowulf Cluster. The first run of the full simulation showed that the time required for calculation decreased linearly increasing the number of distributed processes. The good scalability trend allows both statistically significant accuracy and good time performances. The scalability of the Beowulf Cluster system offers a new instrument for dose calculation that could be applied in clinical practice. These would be a good support particularly in high challenging prescription that needs good calculation accuracy in zones of high dose gradient and great dishomogeneities
Energy Technology Data Exchange (ETDEWEB)
Lee, Wan; Lee, Byung Do [Dept. of Oral and Maxillofacial Radiology and Wonkwang Dental Research Institute, College of Dentistry, Wonkwang University, Iksan (Korea, Republic of); Lee, Kang Kyoo [Dept. of Radiation Oncology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Koh, Kwang Joon [Dept. of Oral and Maxillofacial Radiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju (Korea, Republic of)
2014-03-15
This study was designed to evaluate whether magnetic resonance imaging (MRI) is appropriate for detecting early changes in the mandibular bone marrow and pulp tissue of rats after high-dose irradiation. The right mandibles of Sprague-Dawley rats were irradiated with 10 Gy (Group 1, n=5) and 20 Gy (Group 2, n=5). Five non-irradiated animals were used as controls. The MR images of rat mandibles were obtained before irradiation and once a week until week 4 after irradiation. From the MR images, the signal intensity (SI) of the mandibular bone marrow and pulp tissue of the incisor was interpreted. The MR images were compared with the histopathologic findings. The SI of the mandibular bone marrow had decreased on T2-weighted MR images. There was little difference between Groups 1 and 2. The SI of the irradiated groups appeared to be lower than that of the control group. The histopathologic findings showed that the trabecular bone in the irradiated group had increased. The SI of the irradiated pulp tissue had decreased on T2-weighted MR images. However, the SI of the MR images in Group 2 was high in the atrophic pulp of the incisor apex at week 2 after irradiation. These patterns seen on MRI in rat bone marrow and pulp tissue were consistent with histopathologic findings. They may be useful to assess radiogenic sclerotic changes in rat mandibular bone marrow.
Smartphone apps for calculating insulin dose: a systematic assessment.
Huckvale, Kit; Adomaviciute, Samanta; Prieto, José Tomás; Leow, Melvin Khee-Shing; Car, Josip
2015-05-06
Medical apps are widely available, increasingly used by patients and clinicians, and are being actively promoted for use in routine care. However, there is little systematic evidence exploring possible risks associated with apps intended for patient use. Because self-medication errors are a recognized source of avoidable harm, apps that affect medication use, such as dose calculators, deserve particular scrutiny. We explored the accuracy and clinical suitability of apps for calculating medication doses, focusing on insulin calculators for patients with diabetes as a representative use for a prevalent long-term condition. We performed a systematic assessment of all English-language rapid/short-acting insulin dose calculators available for iOS and Android. Searches identified 46 calculators that performed simple mathematical operations using planned carbohydrate intake and measured blood glucose. While 59% (n = 27/46) of apps included a clinical disclaimer, only 30% (n = 14/46) documented the calculation formula. 91% (n = 42/46) lacked numeric input validation, 59% (n = 27/46) allowed calculation when one or more values were missing, 48% (n = 22/46) used ambiguous terminology, 9% (n = 4/46) did not use adequate numeric precision and 4% (n = 2/46) did not store parameters faithfully. 67% (n = 31/46) of apps carried a risk of inappropriate output dose recommendation that either violated basic clinical assumptions (48%, n = 22/46) or did not match a stated formula (14%, n = 3/21) or correctly update in response to changing user inputs (37%, n = 17/46). Only one app, for iOS, was issue-free according to our criteria. No significant differences were observed in issue prevalence by payment model or platform. The majority of insulin dose calculator apps provide no protection against, and may actively contribute to, incorrect or inappropriate dose recommendations that put current users at risk of both catastrophic overdose and more
Parallel processing of dose calculation for external photon beam therapy
International Nuclear Information System (INIS)
Kunieda, Etsuo; Ando, Yutaka; Tsukamoto, Nobuhiro; Ito, Hisao; Kubo, Atsushi
1994-01-01
We implemented external photon beam dose calculation programs into a parallel processor system consisting of Transputers, 32-bit processors especially suitable for multi-processor configuration. Two network conformations, binary-tree and pipeline, were evaluated for rectangular and irregular field dose calculation algorithms. Although computation speed increased in proportion to the number of CPU, substantial overhead caused by inter-processor communication occurred when a smaller computation load was delivered to each processor. On the other hand, for irregular field calculation, which requires more computation capability for each calculation point, the communication overhead was still less even when more than 50 processors were involved. Real-time responses could be expected for more complex algorithms by increasing the number of processors. (author)
Energy Technology Data Exchange (ETDEWEB)
Willegaignon, Jose; Pelissoni, Rogerio Alexandre; Lima, Beatriz Christine de Godoy Diniz; Coura-Filho, George Barberio; Queiroz, Marcelo Araujo, E-mail: j.willegaignon@gmail.com [Instituto do Cancer do Estado de Sao Paulo Octavio Frias de Oliveira (ICESP), Sao Paulo, SP (Brazil); Sapienza, Marcelo Tatit; Buchpiguel, Carlos Alberto [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Departamento de Radiologia
2016-05-15
Objective: to compare the probe detection method with the image quantification method when estimating {sup 131}I biokinetics and radiation doses to the red marrow and whole body in the treatment of thyroid cancer patients. Materials and methods: fourteen patients with metastatic thyroid cancer, without metastatic bone involvement, were submitted to therapy planning in order to tailor the therapeutic amount of {sup 131}I to each individual. Whole-body scans and probe measurements were performed at 4, 24, 48, 72, and 96 h after {sup 131}I administration in order to estimate the effective half-life (T{sub eff}) and residence time of {sup 131}I in the body. Results: the mean values for T{sub eff} and residence time, respectively, were 19 ± 9 h and 28 ± 12 h for probe detection, compared with 20 ± 13 h and 29 ± 18 h for image quantification. The average dose to the red marrow and whole body, respectively, was 0.061 ± 0.041 mGy/MBq and 0.073 ± 0.040 mGy/MBq for probe detection, compared with 0.066 ± 0.055 mGy/MBq and 0.078 ± 0.056 mGy/MBq for image quantification. Statistical analysis proved that there were no significant differences between the two methods for estimating the T{sub eff} (p = 0.801), residence time (p = 0.801), dose to the red marrow (p = 0.708), and dose to the whole body (p = 0.811), even when we considered an optimized approach for calculating doses only at 4 h and 96 h after {sup 131}I administration (p > 0.914). Conclusion: there is full agreement as to the feasibility of using probe detection and image quantification when estimating {sup 131}I biokinetics and red-marrow/whole-body doses. However, because the probe detection method is ineffective in identifying tumor sites and critical organs during radionuclide therapy and therefore liable to skew adjustment of the amount of {sup 131}I to be administered to patients under such therapy, it should be used with caution. (author)
A Monte Carlo dose calculation tool for radiotherapy treatment planning
International Nuclear Information System (INIS)
Ma, C.-M.; Li, J.S.; Pawlicki, T.; Jiang, S.B.; Deng, J.; Lee, M.C.; Koumrian, T.; Luxton, M.; Brain, S.
2002-01-01
A Monte Carlo user code, MCDOSE, has been developed for radiotherapy treatment planning (RTP) dose calculations. MCDOSE is designed as a dose calculation module suitable for adaptation to host RTP systems. MCDOSE can be used for both conventional photon/electron beam calculation and intensity modulated radiotherapy (IMRT) treatment planning. MCDOSE uses a multiple-source model to reconstruct the treatment beam phase space. Based on Monte Carlo simulated or measured beam data acquired during commissioning, source-model parameters are adjusted through an automated procedure. Beam modifiers such as jaws, physical and dynamic wedges, compensators, blocks, electron cut-outs and bolus are simulated by MCDOSE together with a 3D rectilinear patient geometry model built from CT data. Dose distributions calculated using MCDOSE agreed well with those calculated by the EGS4/DOSXYZ code using different beam set-ups and beam modifiers. Heterogeneity correction factors for layered-lung or layered-bone phantoms as calculated by both codes were consistent with measured data to within 1%. The effect of energy cut-offs for particle transport was investigated. Variance reduction techniques were implemented in MCDOSE to achieve a speedup factor of 10-30 compared to DOSXYZ. (author)
Energy Technology Data Exchange (ETDEWEB)
Moore, Bria M.; Brady, Samuel L., E-mail: samuel.brady@stjude.org; Kaufman, Robert A. [Department of Radiological Sciences, St Jude Children' s Research Hospital, Memphis, Tennessee 38105 (United States); Mirro, Amy E. [Department of Biomedical Engineering, Washington University, St Louis, Missouri 63130 (United States)
2014-07-15
Purpose: To investigate the correlation of size-specific dose estimate (SSDE) with absorbed organ dose, and to develop a simple methodology for estimating patient organ dose in a pediatric population (5–55 kg). Methods: Four physical anthropomorphic phantoms representing a range of pediatric body habitus were scanned with metal oxide semiconductor field effect transistor (MOSFET) dosimeters placed at 23 organ locations to determine absolute organ dose. Phantom absolute organ dose was divided by phantom SSDE to determine correlation between organ dose and SSDE. Organ dose correlation factors (CF{sub SSDE}{sup organ}) were then multiplied by patient-specific SSDE to estimate patient organ dose. The CF{sub SSDE}{sup organ} were used to retrospectively estimate individual organ doses from 352 chest and 241 abdominopelvic pediatric CT examinations, where mean patient weight was 22 kg ± 15 (range 5–55 kg), and mean patient age was 6 yrs ± 5 (range 4 months to 23 yrs). Patient organ dose estimates were compared to published pediatric Monte Carlo study results. Results: Phantom effective diameters were matched with patient population effective diameters to within 4 cm; thus, showing appropriate scalability of the phantoms across the entire pediatric population in this study. IndividualCF{sub SSDE}{sup organ} were determined for a total of 23 organs in the chest and abdominopelvic region across nine weight subcategories. For organs fully covered by the scan volume, correlation in the chest (average 1.1; range 0.7–1.4) and abdominopelvic region (average 0.9; range 0.7–1.3) was near unity. For organ/tissue that extended beyond the scan volume (i.e., skin, bone marrow, and bone surface), correlation was determined to be poor (average 0.3; range: 0.1–0.4) for both the chest and abdominopelvic regions, respectively. A means to estimate patient organ dose was demonstrated. Calculated patient organ dose, using patient SSDE and CF{sub SSDE}{sup organ}, was compared to
New formula for calculation of cobalt-60 percent depth dose
International Nuclear Information System (INIS)
Tahmasebi Birgani, M. J.; Ghorbani, M.
2005-01-01
On the basis of percent depth dose calculation, the application of - dosimetry in radiotherapy has an important role to play in reducing the chance of tumor recurrence. The aim of this study is to introduce a new formula for calculating the central axis percent depth doses of Cobalt-60 beam. Materials and Methods: In the present study, based on the British Journal of Radiology table, nine new formulas are developed and evaluated for depths of 0.5 - 30 cm and fields of (4*4) - (45*45) cm 2 . To evaluate the agreement between the formulas and the table, the average of the absolute differences between the values was used and the formula with the least average was selected as the best fitted formula. The Microsoft Excel 2000 and the Data fit 8.0 soft wares were used to perform the calculations. Results: The results of this study indicated that one amongst the nine formulas gave a better agreement with the percent depth doses listed in the table of British Journal of Radiology . The new formula has two parts in terms of log (A/P). The first part as a linear function with the depth in the range of 0.5 to 5 cm and the other one as a second order polynomial with the depth in the range of 6 to 30 cm. The average of - the differences between the tabulated and the calculated data using the formula (Δ) is equal to 0.3 152. Discussion and Conclusion: Therefore, the calculated percent depth dose data based on this formula has a better agreement with the published data for Cobalt-60 source. This formula could be used to calculate the percent depth dose for the depths and the field sizes not listed in the British Journal of Radiology table
CT dose profiles and MSAD calculation in a chest phantom
International Nuclear Information System (INIS)
Oliveira, Bruno Beraldo; Silva, Teogenes Augusto da
2011-01-01
For optimizing patient doses in computed tomography (CT), the Brazilian legislation has only established diagnostic reference levels (DRLs) in terms of Multiple Scan Average Dose (MSAD) in a typical adult as a quality control parameter for CT scanners. Compliance with the DRLs can be verified by measuring the Computed Tomography Air Kerma Index with a calibrated pencil ionization chamber or by obtaining the dose distribution in CT scans. An analysis of the quality of five CT scanners in Belo Horizonte was done in terms of dose profile of chest scans and MSAD determinations. Measurements were done with rod shape lithium fluoride thermoluminescent dosimeters (TLD-100) distributed in cylinders positioned in peripheral and central regions of a polymethylmethacrylate chest phantom. The peripheral regions presented higher dose values. The longitudinal dose variation can be observed and the maximum dose was recorded at the edges of the phantom at the midpoint of the longitudinal axis. The MSAD results were in according to the DRL of 25 mGy established by Brazilian legislation. The results contribute to disseminate to hospitals and radiologists the proper procedure to use the thermoluminescent dosimeters for the calculation of the MSAD from the CT dose profiles and to notice the compliance with the DRLs. (author)
Activities of the ICRP task group on dose calculations (DOCAL)
International Nuclear Information System (INIS)
Bertelli, Luiz
1997-01-01
Full text. The International Commission of Radiological Protection has been doing many efforts to improve dose calculations due to intake of radionuclides by workers and members of the public. More specifically, the biokinetic models have become more and more physiologically based and developed for age-groups ranging from the embryo to the adult. The dosimetric aspects have also been very carefully revised and a new series of phantoms encompassing all developing stages of embryo and fetus were also envisaged. In order to assure the quality of the calculations, dose coefficients have been derived by two different laboratories and the results and methods have been frequently compared and discussed. A CD-ROM has been prepared allowing the user to obtain dose coefficients for the several age-groups for ingestion and inhalation of all important radionuclides. Inhalation dose coefficients will be available for several AMADs. For the particular case of embryo and fetus, doses will be calculated when the intake occurred before and during gestation for single and chronic patterns of intake
Gonadal status following bone marrow transplantation with low dose busulfan-cyclophosphamide regimen
Directory of Open Access Journals (Sweden)
Mohsen Khosh niat Nikoo
2006-02-01
Full Text Available Background: Gonadal dysfunction is one of the short and long-term side effects following bone marrow transplantation (BMT. We assessed hypophyseal-gonadal axis after BMT by low dose busulfan-cyclophosphamide conditioning regimen (120 mg/kg. Methods: In this cohort study, we evaluated gonadal function in 48 patients (25 pubert males and 23 pubert females. Data were obtained by history, physical examination, LH, FSH, prolactin, estradiol (E2, progesterone, testosterone and semen analysis before BMT and in 6 and 12 months of post-BMT. Results: Gonadal axis in 16 male subjects (64% was normal before BMT and remained normal in 6 subjects (37% 12 months post BMT. In another 10 patients (63%, hypogonadism was started in 6 months post BMT. Spermatogenesis failure (31%, low level of testosterone (25% and spermatogenesis failure plus low level of testosterone in 12.5% were found. Gonadal axis in 20 female subjects (87% was normal before BMT, but remained normal only in 10% of subject until the end of the study. Other patients (90% had primary hypogonadism in 6 months of post BMT. Conclusion: There is a high prevalence of gonadal dysfunction following BMT in both adult sexes (especially in female patients. Therefore, regular gonadal assessment is recommended following BMT.
Approaches to reducing photon dose calculation errors near metal implants
Energy Technology Data Exchange (ETDEWEB)
Huang, Jessie Y.; Followill, David S.; Howell, Rebecca M.; Mirkovic, Dragan; Kry, Stephen F., E-mail: sfkry@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, The University of Texas Health Science Center Houston, Houston, Texas 77030 (United States); Liu, Xinming [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, The University of Texas Health Science Center Houston, Houston, Texas 77030 (United States); Stingo, Francesco C. [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, The University of Texas Health Science Center Houston, Houston, Texas 77030 (United States)
2016-09-15
Purpose: Dose calculation errors near metal implants are caused by limitations of the dose calculation algorithm in modeling tissue/metal interface effects as well as density assignment errors caused by imaging artifacts. The purpose of this study was to investigate two strategies for reducing dose calculation errors near metal implants: implementation of metal-based energy deposition kernels in the convolution/superposition (C/S) dose calculation method and use of metal artifact reduction methods for computed tomography (CT) imaging. Methods: Both error reduction strategies were investigated using a simple geometric slab phantom with a rectangular metal insert (composed of titanium or Cerrobend), as well as two anthropomorphic phantoms (one with spinal hardware and one with dental fillings), designed to mimic relevant clinical scenarios. To assess the dosimetric impact of metal kernels, the authors implemented titanium and silver kernels in a commercial collapsed cone C/S algorithm. To assess the impact of CT metal artifact reduction methods, the authors performed dose calculations using baseline imaging techniques (uncorrected 120 kVp imaging) and three commercial metal artifact reduction methods: Philips Healthcare’s O-MAR, GE Healthcare’s monochromatic gemstone spectral imaging (GSI) using dual-energy CT, and GSI with metal artifact reduction software (MARS) applied. For the simple geometric phantom, radiochromic film was used to measure dose upstream and downstream of metal inserts. For the anthropomorphic phantoms, ion chambers and radiochromic film were used to quantify the benefit of the error reduction strategies. Results: Metal kernels did not universally improve accuracy but rather resulted in better accuracy upstream of metal implants and decreased accuracy directly downstream. For the clinical cases (spinal hardware and dental fillings), metal kernels had very little impact on the dose calculation accuracy (<1.0%). Of the commercial CT artifact
Approaches to reducing photon dose calculation errors near metal implants
International Nuclear Information System (INIS)
Huang, Jessie Y.; Followill, David S.; Howell, Rebecca M.; Mirkovic, Dragan; Kry, Stephen F.; Liu, Xinming; Stingo, Francesco C.
2016-01-01
Purpose: Dose calculation errors near metal implants are caused by limitations of the dose calculation algorithm in modeling tissue/metal interface effects as well as density assignment errors caused by imaging artifacts. The purpose of this study was to investigate two strategies for reducing dose calculation errors near metal implants: implementation of metal-based energy deposition kernels in the convolution/superposition (C/S) dose calculation method and use of metal artifact reduction methods for computed tomography (CT) imaging. Methods: Both error reduction strategies were investigated using a simple geometric slab phantom with a rectangular metal insert (composed of titanium or Cerrobend), as well as two anthropomorphic phantoms (one with spinal hardware and one with dental fillings), designed to mimic relevant clinical scenarios. To assess the dosimetric impact of metal kernels, the authors implemented titanium and silver kernels in a commercial collapsed cone C/S algorithm. To assess the impact of CT metal artifact reduction methods, the authors performed dose calculations using baseline imaging techniques (uncorrected 120 kVp imaging) and three commercial metal artifact reduction methods: Philips Healthcare’s O-MAR, GE Healthcare’s monochromatic gemstone spectral imaging (GSI) using dual-energy CT, and GSI with metal artifact reduction software (MARS) applied. For the simple geometric phantom, radiochromic film was used to measure dose upstream and downstream of metal inserts. For the anthropomorphic phantoms, ion chambers and radiochromic film were used to quantify the benefit of the error reduction strategies. Results: Metal kernels did not universally improve accuracy but rather resulted in better accuracy upstream of metal implants and decreased accuracy directly downstream. For the clinical cases (spinal hardware and dental fillings), metal kernels had very little impact on the dose calculation accuracy (<1.0%). Of the commercial CT artifact
Analytical probabilistic proton dose calculation and range uncertainties
Bangert, M.; Hennig, P.; Oelfke, U.
2014-03-01
We introduce the concept of analytical probabilistic modeling (APM) to calculate the mean and the standard deviation of intensity-modulated proton dose distributions under the influence of range uncertainties in closed form. For APM, range uncertainties are modeled with a multivariate Normal distribution p(z) over the radiological depths z. A pencil beam algorithm that parameterizes the proton depth dose d(z) with a weighted superposition of ten Gaussians is used. Hence, the integrals ∫ dz p(z) d(z) and ∫ dz p(z) d(z)2 required for the calculation of the expected value and standard deviation of the dose remain analytically tractable and can be efficiently evaluated. The means μk, widths δk, and weights ωk of the Gaussian components parameterizing the depth dose curves are found with least squares fits for all available proton ranges. We observe less than 0.3% average deviation of the Gaussian parameterizations from the original proton depth dose curves. Consequently, APM yields high accuracy estimates for the expected value and standard deviation of intensity-modulated proton dose distributions for two dimensional test cases. APM can accommodate arbitrary correlation models and account for the different nature of random and systematic errors in fractionated radiation therapy. Beneficial applications of APM in robust planning are feasible.
A formalism for independent checking of Gamma Knife dose calculations
International Nuclear Information System (INIS)
Tsai Jensan; Engler, Mark J.; Rivard, Mark J.; Mahajan, Anita; Borden, Jonathan A.; Zheng Zhen
2001-01-01
For stereotactic radiosurgery using the Leksell Gamma Knife system, it is important to perform a pre-treatment verification of the maximum dose calculated with the Leksell GammaPlan[reg] (D LGP ) stereotactic radiosurgery system. This verification can be incorporated as part of a routine quality assurance (QA) procedure to minimize the chance of a hazardous overdose. To implement this procedure, a formalism has been developed to calculate the dose D CAL (X,Y,Z,d av ,t) using the following parameters: average target depth (d av ), coordinates (X,Y,Z) of the maximum dose location or any other dose point(s) to be verified, 3-dimensional (3-dim) beam profiles or off-center-ratios (OCR) of the four helmets, helmet size i, output factor O i , plug factor P i , each shot j coordinates (x,y,z) i,j , and shot treatment time (t i,j ). The average depth of the target d av was obtained either from MRI/CT images or ruler measurements of the Gamma Knife Bubble Head Frame. D CAL and D LGP were then compared to evaluate the accuracy of this independent calculation. The proposed calculation for an independent check of D LGP has been demonstrated to be accurate and reliable, and thus serves as a QA tool for Gamma Knife stereotactic radiosurgery
Methods for calculating population dose from atmospheric dispersion of radioactivity
Energy Technology Data Exchange (ETDEWEB)
Cohen, B L; Jow, H N; Lee, I S [Pittsburgh Univ., PA (USA)
1978-06-01
Curves are computed from which population dose (man-rem) due to dispersal of radioactivity from a point source can be calculated in the gaussian plume model by simple multiplication, and methods of using them and their limitations are considered. Illustrative examples are presented.
Touch screen man machine interfere for emergency dose calculations
International Nuclear Information System (INIS)
Woodard, K.; Abrams, M.
1987-01-01
Emergency dose calculation systems generally use a keyboard to provide the interface between the user and the computer. This interface is preferred by users who work daily with computers; however, for many plant personnel who are not continuously involved with computer operations, the use of a keyboard can be cumbersome and time consuming. This is particularly true when the user is under pressure during a drill or an actual emergency. Experience in many applications of Pickard, Lowe and Garrick's PLG's Meteorological Information and Dose Assessment System (MIDAS) has shown that user friendliness is a key ingredient toward achieving acceptance of computerized systems. Hardware to support to touch screen interface is now available and has been implemented in MIDAS. Recent experience has demonstrated that selection times for dose calculations are reduced, data entry errors have been minimized, and confusion over appropriate entries has been avoided due to the built-in logic. A 10-yr search for an acceptable keyboard replacement has ended
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.
Development of new methodology for dose calculation in photographic dosimetry
International Nuclear Information System (INIS)
Daltro, T.F.L.; Campos, L.L.; Perez, H.E.B.
1996-01-01
The personal dosemeter system of IPEN is based on film dosimetry. Personal doses at IPEN are mainly due to X or gamma radiation. The use of personal photographic dosemeters involves two steps: firstly, data acquisition including their evaluation with respect to the calibration quantity and secondly, the interpretation of the data in terms of effective dose. The effective dose was calculated using artificial intelligence techniques by means of neural network. The learning of the neural network was performed by taking the readings of optical density as a function of incident energy and exposure from the calibration curve. The obtained output in the daily grind is the mean effective energy and the effective dose. (author)
Calculations of dose distributions using a neural network model
International Nuclear Information System (INIS)
Mathieu, R; Martin, E; Gschwind, R; Makovicka, L; Contassot-Vivier, S; Bahi, J
2005-01-01
The main goal of external beam radiotherapy is the treatment of tumours, while sparing, as much as possible, surrounding healthy tissues. In order to master and optimize the dose distribution within the patient, dosimetric planning has to be carried out. Thus, for determining the most accurate dose distribution during treatment planning, a compromise must be found between the precision and the speed of calculation. Current techniques, using analytic methods, models and databases, are rapid but lack precision. Enhanced precision can be achieved by using calculation codes based, for example, on Monte Carlo methods. However, in spite of all efforts to optimize speed (methods and computer improvements), Monte Carlo based methods remain painfully slow. A newer way to handle all of these problems is to use a new approach in dosimetric calculation by employing neural networks. Neural networks (Wu and Zhu 2000 Phys. Med. Biol. 45 913-22) provide the advantages of those various approaches while avoiding their main inconveniences, i.e., time-consumption calculations. This permits us to obtain quick and accurate results during clinical treatment planning. Currently, results obtained for a single depth-dose calculation using a Monte Carlo based code (such as BEAM (Rogers et al 2003 NRCC Report PIRS-0509(A) rev G)) require hours of computing. By contrast, the practical use of neural networks (Mathieu et al 2003 Proceedings Journees Scientifiques Francophones, SFRP) provides almost instant results and quite low errors (less than 2%) for a two-dimensional dosimetric map
Effective dose calculation in CT using high sensitivity TLDs
International Nuclear Information System (INIS)
Brady, Z.; Johnston, P.N.
2010-01-01
Full text: To determine the effective dose for common paediatric CT examinations using thermoluminescence dosimetry (TLD) mea surements. High sensitivity TLD chips (LiF:Mg,Cu,P, TLD-IOOH, Thermo Fisher Scientific, Waltham, MA) were calibrated on a linac at an energy of 6 MY. A calibration was also performed on a superricial X-ray unit at a kilovoltage energy to validate the megavoltage cali bration for the purpose of measuring doses in the diagnostic energy range. The dose variation across large organs was assessed and a methodology for TLD placement in a 10 year old anthropomorphic phantom developed. Effective dose was calculated from the TLD measured absorbed doses for typical CT examinations after correcting for the TLD energy response and taking into account differences in the mass energy absorption coefficients for different tissues and organs. Results Using new tissue weighting factors recommended in ICRP Publication 103, the effective dose for a CT brain examination on a 10 year old was 1.6 millisieverts (mSv), 4.9 mSv for a CT chest exa ination and 4.7 mSv for a CT abdomen/pelvis examination. These values are lower for the CT brain examination, higher for the CT chest examination and approximately the same for the CT abdomen/ pelvis examination when compared with effective doses calculated using ICRP Publication 60 tissue weighting factors. Conclusions High sensitivity TLDs calibrated with a radiotherapy linac are useful for measuring dose in the diagnostic energy range and overcome limitations of output reproducibility and uniformity asso ciated with traditional TLD calibration on CT scanners or beam quality matched diagnostic X-ray units.
Dose Calculation Evolution for Internal Organ Irradiation in Humans
International Nuclear Information System (INIS)
Jimenez V, Reina A.
2007-01-01
The International Commission of Radiation Units (ICRU) has established through the years, a discrimination system regarding the security levels on the prescription and administration of doses in radiation treatments (Radiotherapy, Brach therapy, Nuclear Medicine). The first level is concerned with the prescription and posterior assurance of dose administration to a point of interest (POI), commonly located at the geometrical center of the region to be treated. In this, the effects of radiation around that POI, is not a priority. The second level refers to the dose specifications in a particular plane inside the patient, mostly the middle plane of the lesion. The dose is calculated to all the structures in that plane regardless if they are tumor or healthy tissue. In this case, the dose is not represented by a point value, but by level curves called 'isodoses' as in a topographic map, so you can assure the level of doses to this particular plane, but it also leave with no information about how this values go thru adjacent planes. This is why the third level is referred to the volumetrical description of doses so these isodoses construct now a volume (named 'cloud') that give us better assurance about tissue irradiation around the volume of the lesion and its margin (sub clinical spread or microscopic illness). This work shows how this evolution has resulted, not only in healthy tissue protection improvement but in a rise of tumor control, quality of life, better treatment tolerance and minimum permanent secuelae
Fast optimization and dose calculation in scanned ion beam therapy
International Nuclear Information System (INIS)
Hild, S.; Graeff, C.; Trautmann, J.; Kraemer, M.; Zink, K.; Durante, M.; Bert, C.
2014-01-01
Purpose: Particle therapy (PT) has advantages over photon irradiation on static tumors. An increased biological effectiveness and active target conformal dose shaping are strong arguments for PT. However, the sensitivity to changes of internal geometry complicates the use of PT for moving organs. In case of interfractionally moving objects adaptive radiotherapy (ART) concepts known from intensity modulated radiotherapy (IMRT) can be adopted for PT treatments. One ART strategy is to optimize a new treatment plan based on daily image data directly before a radiation fraction is delivered [treatment replanning (TRP)]. Optimizing treatment plans for PT using a scanned beam is a time consuming problem especially for particles other than protons where the biological effective dose has to be calculated. For the purpose of TRP, fast optimization and fast dose calculation have been implemented into the GSI in-house treatment planning system (TPS) TRiP98. Methods: This work reports about the outcome of a code analysis that resulted in optimization of the calculation processes as well as implementation of routines supporting parallel execution of the code. To benchmark the new features, the calculation time for therapy treatment planning has been studied. Results: Compared to the original version of the TPS, calculation times for treatment planning (optimization and dose calculation) have been improved by a factor of 10 with code optimization. The parallelization of the TPS resulted in a speedup factor of 12 and 5.5 for the original version and the code optimized version, respectively. Hence the total speedup of the new implementation of the authors' TPS yielded speedup factors up to 55. Conclusions: The improved TPS is capable of completing treatment planning for ion beam therapy of a prostate irradiation considering organs at risk in this has been overseen in the review process. Also see below 6 min
A convolution-superposition dose calculation engine for GPUs
Energy Technology Data Exchange (ETDEWEB)
Hissoiny, Sami; Ozell, Benoit; Despres, Philippe [Departement de genie informatique et genie logiciel, Ecole polytechnique de Montreal, 2500 Chemin de Polytechnique, Montreal, Quebec H3T 1J4 (Canada); Departement de radio-oncologie, CRCHUM-Centre hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1 (Canada)
2010-03-15
Purpose: Graphic processing units (GPUs) are increasingly used for scientific applications, where their parallel architecture and unprecedented computing power density can be exploited to accelerate calculations. In this paper, a new GPU implementation of a convolution/superposition (CS) algorithm is presented. Methods: This new GPU implementation has been designed from the ground-up to use the graphics card's strengths and to avoid its weaknesses. The CS GPU algorithm takes into account beam hardening, off-axis softening, kernel tilting, and relies heavily on raytracing through patient imaging data. Implementation details are reported as well as a multi-GPU solution. Results: An overall single-GPU acceleration factor of 908x was achieved when compared to a nonoptimized version of the CS algorithm implemented in PlanUNC in single threaded central processing unit (CPU) mode, resulting in approximatively 2.8 s per beam for a 3D dose computation on a 0.4 cm grid. A comparison to an established commercial system leads to an acceleration factor of approximately 29x or 0.58 versus 16.6 s per beam in single threaded mode. An acceleration factor of 46x has been obtained for the total energy released per mass (TERMA) calculation and a 943x acceleration factor for the CS calculation compared to PlanUNC. Dose distributions also have been obtained for a simple water-lung phantom to verify that the implementation gives accurate results. Conclusions: These results suggest that GPUs are an attractive solution for radiation therapy applications and that careful design, taking the GPU architecture into account, is critical in obtaining significant acceleration factors. These results potentially can have a significant impact on complex dose delivery techniques requiring intensive dose calculations such as intensity-modulated radiation therapy (IMRT) and arc therapy. They also are relevant for adaptive radiation therapy where dose results must be obtained rapidly.
Monte Carlo dose calculations for phantoms with hip prostheses
International Nuclear Information System (INIS)
Bazalova, M; Verhaegen, F; Coolens, C; Childs, P; Cury, F; Beaulieu, L
2008-01-01
Computed tomography (CT) images of patients with hip prostheses are severely degraded by metal streaking artefacts. The low image quality makes organ contouring more difficult and can result in large dose calculation errors when Monte Carlo (MC) techniques are used. In this work, the extent of streaking artefacts produced by three common hip prosthesis materials (Ti-alloy, stainless steel, and Co-Cr-Mo alloy) was studied. The prostheses were tested in a hypothetical prostate treatment with five 18 MV photon beams. The dose distributions for unilateral and bilateral prosthesis phantoms were calculated with the EGSnrc/DOSXYZnrc MC code. This was done in three phantom geometries: in the exact geometry, in the original CT geometry, and in an artefact-corrected geometry. The artefact-corrected geometry was created using a modified filtered back-projection correction technique. It was found that unilateral prosthesis phantoms do not show large dose calculation errors, as long as the beams miss the artefact-affected volume. This is possible to achieve in the case of unilateral prosthesis phantoms (except for the Co-Cr-Mo prosthesis which gives a 3% error) but not in the case of bilateral prosthesis phantoms. The largest dose discrepancies were obtained for the bilateral Co-Cr-Mo hip prosthesis phantom, up to 11% in some voxels within the prostate. The artefact correction algorithm worked well for all phantoms and resulted in dose calculation errors below 2%. In conclusion, a MC treatment plan should include an artefact correction algorithm when treating patients with hip prostheses
Accumulated dose calculations in Indian PHWRs under DBA
International Nuclear Information System (INIS)
Nesaraj, David; Pradhan, A.S.; Bhardwaj, S.A.
1996-01-01
Accumulated gamma dose inside reactor building due to release of fission products from equilibrium core of Indian PHWR under accident condition has been assessed. The assessment has been done for the radiation tolerance limit of the critical equipment inside reactor building. The basic source data has been generated using computer code ORIGEN2 written and developed by Oak Ridge National Laboratory, USA (ORNL). This paper discusses the details of the calculations done on the basis of certain assumption which are mentioned at relevant places. The results indicate accumulated gamma dose at a few typical locations inside reactor building under accident condition. (author). 1 ref., 1 tab., 1 fig
Calculation of radiation dose received in computed tomography examinations
International Nuclear Information System (INIS)
Abed Elseed, Eslam Mustafa
2014-07-01
Diagnostic computed tomography (CT) examinations play an important role in the health care of the population. These examination may involve significant irradiation of the patient and probably represent the largest man-made source of radiation exposure for the population. This study was performed to assess the effective dose (ED) received in brain CT examination ( base of skull and cerebrum) and to analyze effective dose distributions among radiological departments under study. The study was performed at Elnileen Medical Center, coverage one CT unit and a sample of 51 patients (25 cerebrum sample and 26 base of skull sample). The following parameters were recorded age, weight, height body mass index (BMI) derived from weight (kg) and height ( m) and exposure factor and CTDI voi , DLP value. The effective dose was measured for brain CT examination. The ED values were calculated from the obtained DLP values using AAPM report No 96 calculation methods. The results of ED values calculated showed that patient exposure were within the normal range of exposure. The mean ED values calculated were 0.35±0.15 for base of skull of brain CT examinations and 0.70±0.32 for cerebrum of brain CT examination, respectively. Further studies are recommended with more number of pa.(Author)
Internal dose conversion factors for calculation of dose to the public
International Nuclear Information System (INIS)
1988-07-01
This publication contains 50-year committed dose equivalent factors, in tabular form. The document is intended to be used as the primary reference by the US Department of Energy (DOE) and its contractors for calculating radiation dose equivalents for members of the public, resulting from ingestion or inhalation of radioactive materials. Its application is intended specifically for such materials released to the environment during routine DOE operations, except in those instances where compliance with 40 CFR 61 (National Emission Standards for Hazardous Air Pollutants) requires otherwise. However, the calculated values may be equally applicable to unusual releases or to occupational exposures. The use of these committed dose equivalent tables should ensure that doses to members of the public from internal exposures are calculated in a consistent manner at all DOE facilities
Monte Carlo dose calculation of microbeam in a lung phantom
International Nuclear Information System (INIS)
Company, F.Z.; Mino, C.; Mino, F.
1998-01-01
Full text: Recent advances in synchrotron generated X-ray beams with high fluence rate permit investigation of the application of an array of closely spaced, parallel or converging microplanar beams in radiotherapy. The proposed techniques takes advantage of the hypothesised repair mechanism of capillary cells between alternate microbeam zones, which regenerates the lethally irradiated endothelial cells. The lateral and depth doses of 100 keV microplanar beams are investigated for different beam dimensions and spacings in a tissue, lung and tissue/lung/tissue phantom. The EGS4 Monte Carlo code is used to calculate dose profiles at different depth and bundles of beams (up to 20x20cm square cross section). The maximum dose on the beam axis (peak) and the minimum interbeam dose (valley) are compared at different depths, bundles, heights, widths and beam spacings. Relatively high peak to valley ratios are observed in the lung region, suggesting an ideal environment for microbeam radiotherapy. For a single field, the ratio at the tissue/lung interface will set the maximum dose to the target volume. However, in clinical application, several fields would be involved allowing much greater doses to be applied for the elimination of cancer cells. We conclude therefore that multifield microbeam therapy has the potential to achieve useful therapeutic ratios for the treatment of lung cancer
Comparison of different dose calculation methods for irregular photon fields
International Nuclear Information System (INIS)
Zakaria, G.A.; Schuette, W.
2000-01-01
In this work, 4 calculation methods (Wrede method, Clarskon method of sector integration, beam-zone method of Quast and pencil-beam method of Ahnesjoe) are introduced to calculate point doses in different irregular photon fields. The calculations cover a typical mantle field, an inverted Y-field and different blocked fields for 4 and 10 MV photon energies. The results are compared to those of measurements in a water phantom. The Clarkson and the pencil-beam method have been proved to be the methods of equal standard in relation to accuracy. Both of these methods are being distinguished by minimum deviations and applied in our clinical routine work. The Wrede and beam-zone methods deliver useful results to central beam and yet provide larger deviations in calculating points beyond the central axis. (orig.) [de
External dose-rate conversion factors for calculation of dose to the public
Energy Technology Data Exchange (ETDEWEB)
1988-07-01
This report presents a tabulation of dose-rate conversion factors for external exposure to photons and electrons emitted by radionuclides in the environment. This report was prepared in conjunction with criteria for limiting dose equivalents to members of the public from operations of the US Department of Energy (DOE). The dose-rate conversion factors are provided for use by the DOE and its contractors in performing calculations of external dose equivalents to members of the public. The dose-rate conversion factors for external exposure to photons and electrons presented in this report are based on a methodology developed at Oak Ridge National Laboratory. However, some adjustments of the previously documented methodology have been made in obtaining the dose-rate conversion factors in this report. 42 refs., 1 fig., 4 tabs.
Development of new methodology for dose calculation in photographic dosimetry
International Nuclear Information System (INIS)
Daltro, T.F.L.
1994-01-01
A new methodology for equivalent dose calculations has been developed at IPEN-CNEN/SP to be applied at the Photographic Dosimetry Laboratory using artificial intelligence techniques by means of neutral network. The research was orientated towards the optimization of the whole set of parameters involves in the film processing going from the irradiation in order to obtain the calibration curve up to the optical density readings. The learning of the neutral network was performed by taking the readings of optical density from calibration curve as input and the effective energy and equivalent dose as output. The obtained results in the intercomparison show an excellent agreement with the actual values of dose and energy given by the National Metrology Laboratory of Ionizing Radiation. (author)
Development of new methodology for dose calculation in photographic dosimetry
International Nuclear Information System (INIS)
Daltro, T.F.L.; Campos, L.L.
1994-01-01
A new methodology for equivalent dose calculation has been developed at IPEN-CNEN/SP to be applied at the Photographic Dosimetry Laboratory using artificial intelligence techniques by means of neural network. The research was oriented towards the optimization of the whole set of parameters involved in the film processing going from the irradiation in order to obtain the calibration curve up to the optical density readings. The learning of the neural network was performed by taking readings of optical density from calibration curve as input and the effective energy and equivalent dose as output. The obtained results in the intercomparison show an excellent agreement with the actual values of dose and energy given by the National Metrology Laboratory of Ionizing Radiation
Intravascular brachytherapy: a model for the calculation of the dose
International Nuclear Information System (INIS)
Pirchio, Rosana; Martin, Gabriela; Rivera, Elena; Cricco, Graciela; Cocca, Claudia; Gutierrez, Alicia; Nunez, Mariel; Bergoc, Rosa; Guzman, Luis; Belardi, Diego
2002-01-01
In this study we present the radiation dose distribution for a theoretical model with Montecarlo simulation, and based on an experimental model developed for the study of the prevention of restenosis post-angioplasty employing intravascular brachytherapy. In the experimental in vivo model, the atherosclerotic plaques were induced in femoral arteries of male New Zealand rabbits through surgical intervention and later administration of cholesterol enriched diet. For the intravascular irradiation we employed a 32P source contained within the balloon used for the angioplasty. The radiation dose distributions were calculated using the Monte Carlo code MCNP4B according to a segment of a simulated artery. We studied the radiation dose distribution in the axial and radial directions for different thickness of the atherosclerotic plaques. The results will be correlated with the biologic effects observed by means of histological analysis of the irradiated arteries (Au)
A unique manual method for emergency offsite dose calculations
International Nuclear Information System (INIS)
Wildner, T.E.; Carson, B.H.; Shank, K.E.
1987-01-01
This paper describes a manual method developed for performance of emergency offsite dose calculations for PP and L's Susquehanna Steam Electric Station. The method is based on a three-part carbonless form. The front page guides the user through selection of the appropriate accident case and inclusion of meteorological and effluent data data. By circling the applicable accident descriptors, the user circles the dose factors on pages 2 and 3 which are then simply multiplied to yield the whole body and thyroid dose rates at the plant boundary, two, five, and ten miles. The process used to generate the worksheet is discussed, including the method used to incorporate the observed terrain effects on airflow patterns caused by the Susquehanna River Valley topography
Dose calculation and isodose curves determination in brachytherapy
International Nuclear Information System (INIS)
Maranhao, Frederico B.; Lima, Fernando R.A.; Khoury, Helen J.
2000-01-01
Brachytherapy is a form of cancer treatment in which small radioactive sources are placed inside of, or close to small tumors, in order to cause tissue necrosis and, consequently, to interrupt the tumor growth process. A very important aspect to the planning of this therapy is the calculation of dose distributions in the tumor and nearby tissues, to avoid the unnecessary irradiation of healthy tissue. The objective of this work is to develop a computer program that will permit treatment planning for brachytherapy at low dose rates, minimizing the possible errors introduced when such calculations are done manually. Results obtained showed good agreement with those from programs such as BRA, which is widely used in medical practice. (author)
Development of a computational methodology for internal dose calculations
International Nuclear Information System (INIS)
Yoriyaz, Helio
2000-01-01
A new approach for calculating internal dose estimates was developed through the use of a more realistic computational model of the human body and a more precise tool for the radiation transport simulation. The present technique shows the capability to build a patient-specific phantom with tomography data (a voxel-based phantom) for the simulation of radiation transport and energy deposition using Monte Carlo methods such as in the MCNP-4B code. In order to utilize the segmented human anatomy as a computational model for the simulation of radiation transport, an interface program, SCMS, was developed to build the geometric configurations for the phantom through the use of tomographic images. This procedure allows to calculate not only average dose values but also spatial distribution of dose in regions of interest. With the present methodology absorbed fractions for photons and electrons in various organs of the Zubal segmented phantom were calculated and compared to those reported for the mathematical phantoms of Snyder and Cristy-Eckerman. Although the differences in the organ's geometry between the phantoms are quite evident, the results demonstrate small discrepancies, however, in some cases, considerable discrepancies were found due to two major causes: differences in the organ masses between the phantoms and the occurrence of organ overlap in the Zubal segmented phantom, which is not considered in the mathematical phantom. This effect was quite evident for organ cross-irradiation from electrons. With the determination of spatial dose distribution it was demonstrated the possibility of evaluation of more detailed doses data than those obtained in conventional methods, which will give important information for the clinical analysis in therapeutic procedures and in radiobiologic studies of the human body. (author)
Internal radiation dose calculations with the INREM II computer code
International Nuclear Information System (INIS)
Dunning, D.E. Jr.; Killough, G.G.
1978-01-01
A computer code, INREM II, was developed to calculate the internal radiation dose equivalent to organs of man which results from the intake of a radionuclide by inhalation or ingestion. Deposition and removal of radioactivity from the respiratory tract is represented by the Internal Commission on Radiological Protection Task Group Lung Model. A four-segment catenary model of the gastrointestinal tract is used to estimate movement of radioactive material that is ingested, or swallowed after being cleared from the respiratory tract. Retention of radioactivity in other organs is specified by linear combinations of decaying exponential functions. The formation and decay of radioactive daughters is treated explicitly, with each radionuclide in the decay chain having its own uptake and retention parameters, as supplied by the user. The dose equivalent to a target organ is computed as the sum of contributions from each source organ in which radioactivity is assumed to be situated. This calculation utilizes a matrix of dosimetric S-factors (rem/μCi-day) supplied by the user for the particular choice of source and target organs. Output permits the evaluation of components of dose from cross-irradiations when penetrating radiations are present. INREM II has been utilized with current radioactive decay data and metabolic models to produce extensive tabulations of dose conversion factors for a reference adult for approximately 150 radionuclides of interest in environmental assessments of light-water-reactor fuel cycles. These dose conversion factors represent the 50-year dose commitment per microcurie intake of a given radionuclide for 22target organs including contributions from specified source organs and surplus activity in the rest of the body. These tabulations are particularly significant in their consistent use of contemporary models and data and in the detail of documentation
NAC-1 cask dose rate calculations for LWR spent fuel
International Nuclear Information System (INIS)
CARLSON, A.B.
1999-01-01
A Nuclear Assurance Corporation nuclear fuel transport cask, NAC-1, is being considered as a transport and storage option for spent nuclear fuel located in the B-Cell of the 324 Building. The loaded casks will be shipped to the 200 East Area Interim Storage Area for dry interim storage. Several calculations were performed to assess the photon and neutron dose rates. This report describes the analytical methods, models, and results of this investigation
Data base for terrestrial food pathways dose commitment calculations
International Nuclear Information System (INIS)
Bailey, C.E.
1979-01-01
A computer program is under development to allow calculation of the dose-to-man in Georgia and South Carolina from ingestion of radionuclides in terrestrial foods resulting from deposition of airborne radionuclides. This program is based on models described in Regulatory Guide 1.109 (USNRC, 1977). The data base describes the movement of radionuclides through the terrestrial food chain, growth and consumption factors for a variety of radionuclides
Energy Technology Data Exchange (ETDEWEB)
Giordani, Adelmo Jose; Segreto, Helena Cristina Comodo; Segreto, Roberto Araujo; Medeiros, Regina Bitelli; Oliveira, Jose Salvador R. de [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Setor de Radioterapia]. E-mail: adelmogiordani@ig.com.br
2004-10-01
The objective was to evaluate the precision of the absorbed radiation doses in bone marrow transplant therapy during whole body irradiation. Two-hundred CaSO{sub 4}:Dy + teflon tablets were calibrated in air and in 'phantom'. These tablets were randomly selected and divided in groups of five in the patients' body. The dosimetric readings were obtained using a Harshaw 4000A reader. Nine patients had their entire bodies irradiated in parallel and opposite laterals in a cobalt-60 Alcion II model, with a dose rate of 0.80 Gy/min at 80.5 cm, {l_brace}(10 ? 10) cm{sup 2} field. The dosimetry of this unit was performed using a Victoreen 500 dosimeter. For the determination of the mean dose at each point evaluated, the individual values of the tablets calibrated in air or 'phantom' were used, resulting in a build up of 2 mm to superficialize the dose at a distance of 300 cm. In 70% of the patients a variation of less than 5% in the dose was obtained. In 30% of the patients this variation was less than 10%, when values obtained were compared to the values calculated at each point. A mean absorption of 14% was seen in the head, and an increase of 2% of the administered dose was seen in the lungs. In patients with latero-lateral distance greater than 35 cm the variation between the calculated doses and the measured doses reached 30% of the desired dose, without the use of compensation filters. The measured values of the absorbed doses at the various anatomic points compared to the desired doses (theoretic) presented a tolerance of {+-} 10%, considering the existent anatomical differences and when using the individual calibration factors of the tablets. (author)
[Evaluation of methods to calculate dialysis dose in daily hemodialysis].
Maduell, F; Gutiérrez, E; Navarro, V; Torregrosa, E; Martínez, A; Rius, A
2003-01-01
Daily dialysis has shown excellent clinical results because a higher frequency of dialysis is more physiological. Different methods have been described to calculate dialysis dose which take into consideration change in frequency. The aim of this study was to calculate all dialysis dose possibilities and evaluate the better and practical options. Eight patients, 6 males and 2 females, on standard 4 to 5 hours thrice weekly on-line hemodiafiltration (S-OL-HDF) were switched to daily on-line hemodiafiltration (D-OL-HDF) 2 to 2.5 hours six times per week. Dialysis parameters were identical during both periods and only frequency and dialysis time of each session were changed. Time average concentration (TAC), time average deviation (TAD), normalized protein catabolic rate (nPCR), Kt/V, equilibrated Kt/V (eKt/V), equivalent renal urea clearance (EKR), standard Kt/V (stdKt/V), urea reduction ratio (URR), hemodialysis product and time off dialysis were measured. Daily on-line hemodiafiltration was well accepted and tolerated. Patients maintained the same TAC although TAD decreased from 9.7 +/- 2 in baseline to a 6.2 +/- 2 mg/dl after six months, p time off dialysis was reduced to half. Dialysis frequency is an important urea kinetic parameter which there are to take in consideration. It's necessary to use EKR, stdKt/V or weekly URR to calculate dialysis dose for an adequate comparison between different frequency dialysis schedules.
Dose calculation for iridium-192 sources by a personal computer
International Nuclear Information System (INIS)
Takahashi, Kenichi; Ishigaki, Hideyo; Udagawa, Kimio; Saito, Masami; Yamaguchi, Kyoko
1988-01-01
Recently Ir-192 sources have been used for interstitial radiotherapy instead of Ra-226 needles. One end of Ir-192 (single-pin) is formed with circlet and implanted Ir-192 sources are not always straight line. So the authors have developed a new dose calculation system, in which the authers employed conventional method considering oblique filteration for linear source and multi-point source method for curved source. Conventionally the positions of sources in three dimensions are determined from projections of the implanted sources on orthogonal or stereo radiographs. But it is frequentry impossible to define the end of sources on account of overlap. Then the authers have devised a method to determine the positions of sources from two radiographs which were taken with arbitrary directions. For tongue cancer injuries of mandibula so frequently occur after interstitial radiotherapy that the calculation of gingival dose is necessary. The positions of the gingival line are determined from two directional radiographs too. Further the three dimensional dose distributions can be displayed on the cathod ray tube. These calculations are performed by using a personal computer because of its distinctive features such as superiority in cost performance and flexibility for development and modification of programs. (author)
Korhonen, Juha; Kapanen, Mika; Keyrilainen, Jani; Seppala, Tiina; Tuomikoski, Laura; Tenhunen, Mikko
2013-01-01
Magnetic resonance (MR) images are used increasingly in external radiotherapy target delineation because of their superior soft tissue contrast compared to computed tomography (CT) images. Nevertheless, radiotherapy treatment planning has traditionally been based on the use of CT images, due to the restrictive features of MR images such as lack of electron density information. This research aimed to measure absorbed radiation doses in material behind different bone parts, and to evaluate dose calculation errors in two pseudo-CT images; first, by assuming a single electron density value for the bones, and second, by converting the electron density values inside bones from T(1)∕T(2)∗-weighted MR image intensity values. A dedicated phantom was constructed using fresh deer bones and gelatine. The effect of different bone parts to the absorbed dose behind them was investigated with a single open field at 6 and 15 MV, and measuring clinically detectable dose deviations by an ionization chamber matrix. Dose calculation deviations in a conversion-based pseudo-CT image and in a bulk density pseudo-CT image, where the relative electron density to water for the bones was set as 1.3, were quantified by comparing the calculation results with those obtained in a standard CT image by superposition and Monte Carlo algorithms. The calculations revealed that the applied bulk density pseudo-CT image causes deviations up to 2.7% (6 MV) and 2.0% (15 MV) to the dose behind the examined bones. The corresponding values in the conversion-based pseudo-CT image were 1.3% (6 MV) and 1.0% (15 MV). The examinations illustrated that the representation of the heterogeneous femoral bone (cortex denser compared to core) by using a bulk density for the whole bone causes dose deviations up to 2% both behind the bone edge and the middle part of the bone (diameter bones). This study indicates that the decrease in absorbed dose is not dependent on the bone diameter with all types of bones. Thus
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)
COSANI-2, Gamma Doses from SABINE Calculation, Activity from ANISN Flux Calculation
International Nuclear Information System (INIS)
Dupont, C.
1975-01-01
1 - Nature of physical problem solved: Retrieval of SABINE and/or ANISN results. Calculates in case of SABINE results the individual contributions of capture gamma rays in each region to the total gamma dose and to the total gamma heating may calculate in case of ANISN new activity rates starting from ANISN flux saved on tape and activity cross sections taken on an ANISN binary library tape. The program can draw on a BENSON plotter any of the following quantities: - group flux; - activity rates; - dose rates; - neutron spectra for SABINE; - neutron or gamma direct or adjoint spectra for ANISN; - gamma heating and dose rate for SABINE including individual contributions from each region. Several ANISN and/or SABINE cases can be drawn on the same graph for comparison purposes. 2 - Restrictions on the complexity of the problem: Maximum number of: - tapes containing ANISN and/or SABINE results: 5; - curves per graph: 3; - regions: 40; - points per curve: 500; - energy groups: 200
Domaratskaya, E.; Starostin, V.
The low dose continuous gamma-irradiation chosen corresponded with that affected the organisms onboard a spacecraft (Mitrikas, Tsetlin, 2000). F1 (CBAxC57Bl/6) male and female mice were used at 3 4 months of age. Experimental mice were- irradiated during 10 days to a total dose of 15 mGy (Co60 gamma-sources, mean dose rate of 1.5-2.0 mGy/day). Another group of intact mice served as control. Younger and advanced hemopoietic progenitors measured at day 11 (i.e. CFU -S-11) and day 7 (i.e. CFU-S-7), respectively, after transplantation of test donor cells were assayed by the method of Till and McCulloch (1961). Stromal changes were evaluated by estimation of in vitro fibroblastic colony-forming units (CFU -F ) content and by the ability of ectopically grafted (under renal capsule) stroma to regenerate the new bone marrow organ. CFU-S-11 number increased of 40% as compared with control and almost 2-fold higher than that of CFU-S-7. The CFU-F content increased almost of 3-fold. Size of ectopic marrow transplants was estimated at day 70 following grafting by counting myelokariocyte and CFU -S number that repopulated the newly formed bone marrow organ. It was found more than 2-fold increase of myelokariocytes in transplants produced by marrow stroma of irradiated donors. CFU -S contents in transplants increased strikingly in comparison to control level. CFU-S-7 and CFU-S-11 increased of 7.5- and of 3.7-fold, respectively, i.e. the rate of advanced CFU - S predominated. It should be noted a good correlation between number of stromal progenitor cells (CFU-F) and ectopic transplant sizes evaluated as myelokaryocyte counts when irradiated donors used. In the same time, if sizes of transplants was measured as CFU-S-7 and CFU - S-11 numbers, their increases were more pronounced. Therefore, continuous low dose gamma- irradiation augments significantly both hemopoietic and stromal progenitor cell number in bone marrow. Additionally, the ratio of distinct CFU -S subpopulations
Sini, Carla; Fiorino, Claudio; Perna, Lucia; Noris Chiorda, Barbara; Deantoni, Chiara Lucrezia; Bianchi, Marco; Sacco, Vincenzo; Briganti, Alberto; Montorsi, Francesco; Calandrino, Riccardo; Di Muzio, Nadia; Cozzarini, Cesare
2016-01-01
To prospectively identify clinical/dosimetric predictors of acute/late hematologic toxicity (HT) in chemo-naÏve patients treated with whole-pelvis radiotherapy (WPRT) for prostate cancer. Data of 121 patients treated with adjuvant/salvage WPRT were analyzed (static-field IMRT n=19; VMAT/Rapidarc n=57; Tomotherapy n=45). Pelvic bone marrow (BM) was delineated as ilium (IL), lumbosacral, lower and whole pelvis (WP), and the relative DVHs were calculated. HT was graded both according to CTCAE v4.03 and as variation in percentage relative to baseline. Logistic regression was used to analyze association between HT and clinical/DVHs factors. Significant differences (p<0.005) in the DVH of BM volumes between different techniques were found: Tomotherapy was associated with larger volumes receiving low doses (3-20 Gy) and smaller receiving 40-50 Gy. Lower baseline absolute values of WBC, neutrophils and lymphocytes (ALC) predicted acute/late HT (p ⩽ 0.001). Higher BM V40 was associated with higher risk of acute Grade3 (OR=1.018) or late Grade2 lymphopenia (OR=1.005). Two models predicting lymphopenia were developed, both including baseline ALC, and BM WP-V40 (AUC=0.73) and IL-V40+smoking (AUC=0.904) for acute/late respectively. Specific regions of pelvic BM predicting acute/late lymphopenia, a risk factor for viral infections, were identified. The 2-variable models including specific constraints to BM may help reduce HT. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
TU-AB-BRA-01: Abdominal Synthetic CT Generation in Support of Liver SBRT Dose Calculation
Energy Technology Data Exchange (ETDEWEB)
Bredfeldt, JS; Liu, L; Feng, M [University of Michigan, Ann Arbor, MI (United States); Cao, Y [The University of Michigan, Ann Arbor, MI (United States); Balter, J [University Michigan, Ann Arbor, MI (United States)
2016-06-15
Purpose: To demonstrate and validate a technique for generating MRI-derived synthetic CT volumes (MRCTs) in support of adaptive liver SBRT. Methods: Under IRB approval, ten hepatocellular carcinoma patients were scanned using a single MR sequence (T1 Dixon-VIBE), yielding inherently-registered water, fat, and T1-weighted images. Air-containing voxels were identified by intensity thresholding. The envelope of the anterior vertebral bodies was segmented from the fat image by fitting a shape model to vertebral body candidate voxels, then using level sets to expand the contour outward. Fuzzy-C-Means (FCM) was then used to classify each non-air voxel in the image as fat, water, bone, or marrow. Bone and marrow only were classified within the vertebral body envelope. The MRCT was created by integrating the product of the FCM class probability with the assigned class density for each voxel. The resulting MRCTs were deformably aligned with planning CTs and 2-ARC SBRT VMAT plans were optimized on the MRCT density maps. Fluence was copied onto the CT density grids and dose recalculated. Results: The MRCTs faithfully reproduced most of the features visible in the corresponding CT image volumes, with exceptions of ribs and posterior spinous processes. The liver, vertebral bodies, kidneys, spleen and cord all had median HU differences of less than 75 between MRCT and CT images. PTV D99% values had an average 0.2% difference (standard deviation: 0.46%) between calculations on MRCT and CT density grids. The maximum difference in dose to 0.1cc of the PTV was 0.25% (std:0.49%). OAR dose differences were similarly small (mean:0.03Gy, std:0.26Gy). The largest normal tissue complication percentage (NTCP) difference was 1.48% (mean:0.06%, std:0.54%). Conclusions: MRCTs from a single abdominal imaging sequence are promising for use in SBRT dose calculation. Future work will focus on extending models to better define bones in the upper abdomen. Supported by NIHR01EB016079 and NIH1L30CA
International Nuclear Information System (INIS)
Yun Liang; Messer, Karen; Rose, Brent S.; Lewis, John H.; Jiang, Steve B.; Yashar, Catheryn M.; Mundt, Arno J.; Mell, Loren K.
2010-01-01
Purpose: To study the effects of increasing pelvic bone marrow (BM) radiation dose on acute hematologic toxicity in patients undergoing chemoradiotherapy, using a novel modeling approach to preserve the local spatial dose information. Methods and Materials: The study included 37 cervical cancer patients treated with concurrent weekly cisplatin and pelvic radiation therapy. The white blood cell count nadir during treatment was used as the indicator for acute hematologic toxicity. Pelvic BM radiation dose distributions were standardized across patients by registering the pelvic BM volumes to a common template, followed by dose remapping using deformable image registration, resulting in a dose array. Principal component (PC) analysis was applied to the dose array, and the significant eigenvectors were identified by linear regression on the PCs. The coefficients for PC regression and significant eigenvectors were represented in three dimensions to identify critical BM subregions where dose accumulation is associated with hematologic toxicity. Results: We identified five PCs associated with acute hematologic toxicity. PC analysis regression modeling explained a high proportion of the variation in acute hematologicity (adjusted R 2 , 0.49). Three-dimensional rendering of a linear combination of the significant eigenvectors revealed patterns consistent with anatomical distributions of hematopoietically active BM. Conclusions: We have developed a novel approach that preserves spatial dose information to model effects of radiation dose on toxicity, which may be useful in optimizing radiation techniques to avoid critical subregions of normal tissues. Further validation of this approach in a large cohort is ongoing.
International Nuclear Information System (INIS)
Steiner, H.
1980-01-01
Examples are used to demonstrate that a shift in the point of emphasis is necessary with regard to radiation hazard in medicinal X-ray diagnosis. The parameters employed in this study to calculate somatic dose (SD) and somatically significant dose (SSD) may well be in need of modification; nevertheless the numerical estimation of SSD arrived at here appears to reflect the right order of magnitude for the estimation of somatic risk. The consideration of the threshold dose for somatic injury remains a problem. (orig./MG) [de
Implementation of spot scanning dose optimization and dose calculation for helium ions in Hyperion
DEFF Research Database (Denmark)
Fuchs, Hermann; Alber, Markus; Schreiner, Thomas
2015-01-01
PURPOSE: Helium ions ((4)He) may supplement current particle beam therapy strategies as they possess advantages in physical dose distribution over protons. To assess potential clinical advantages, a dose calculation module accounting for relative biological effectiveness (RBE) was developed...... published so far. The advantage of (4)He seems to lie in the reduction of dose to surrounding tissue and to OARs. Nevertheless, additional biological experiments and treatment planning studies with larger patient numbers and more tumor indications are necessary to study the possible benefits of helium ion...
International Nuclear Information System (INIS)
Bierkens, J.G.; Hendry, J.H.; Testa, N.G.
1991-01-01
Injury inflicted upon the bone marrow stroma following whole-body irradiation and its repair over a 1-year period has been assessed in murine long-term bone marrow cultures established at increasing time intervals after irradiation. Different doses at different dose rates (10 Gy at 0.05 cGy/min, 4.5 Gy and 10 Gy at 1.6 cGy/min, and 4 x 4.5 Gy [3 weeks between doses] at 60 cGy/min) were chosen so as to maximize differences in effect in the stroma. The cellularity of the adherent layer in long-term cultures established 1 month after irradiation was reduced by 40%-90% depending on the dose and dose rate. Simultaneous with the poor ability of the marrow to form adherent layers, the cumulative spleen colony-forming unit (CFU-S) and granulocyte-macrophage colony-forming cell (GM-CFC) production over a 7-week period was reduced to 0% and 30% of control cultures, respectively. The slow recovery of the adherent layer was paralleled by an increase in the numbers of CFU-S and GM-CFC in the supernatant. Cultures established from repeatedly irradiated mice performed poorly over the entire 1-year period. Whereas the regeneration of the stroma was near complete 1 year after irradiation, the CFU-S and GM-CFC levels reached only between 50% and 80% of control cultures, respectively. Also, the concentration of CFU-S and GM-CFC in the supernatant remained persistently lower in cultures established from irradiated mice as compared to control cultures. The levels of sulfated glycosaminoglycans, which have been implicated in the establishment of the functional integrity of the microenvironment, were not reduced in the adherent layers at any time after irradiation. These results indicate that the regeneration of the stroma is accompanied by an incomplete recovery of active hemopoiesis in vitro
International Nuclear Information System (INIS)
Yan Guanghua; Liu, Chihray; Lu Bo; Palta, Jatinder R; Li, Jonathan G
2008-01-01
The purpose of this study was to choose an appropriate head scatter source model for the fast and accurate independent planar dose calculation for intensity-modulated radiation therapy (IMRT) with MLC. The performance of three different head scatter source models regarding their ability to model head scatter and facilitate planar dose calculation was evaluated. A three-source model, a two-source model and a single-source model were compared in this study. In the planar dose calculation algorithm, in-air fluence distribution was derived from each of the head scatter source models while considering the combination of Jaw and MLC opening. Fluence perturbations due to tongue-and-groove effect, rounded leaf end and leaf transmission were taken into account explicitly. The dose distribution was calculated by convolving the in-air fluence distribution with an experimentally determined pencil-beam kernel. The results were compared with measurements using a diode array and passing rates with 2%/2 mm and 3%/3 mm criteria were reported. It was found that the two-source model achieved the best agreement on head scatter factor calculation. The three-source model and single-source model underestimated head scatter factors for certain symmetric rectangular fields and asymmetric fields, but similar good agreement could be achieved when monitor back scatter effect was incorporated explicitly. All the three source models resulted in comparable average passing rates (>97%) when the 3%/3 mm criterion was selected. The calculation with the single-source model and two-source model was slightly faster than the three-source model due to their simplicity
Energy Technology Data Exchange (ETDEWEB)
Yan Guanghua [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States); Liu, Chihray; Lu Bo; Palta, Jatinder R; Li, Jonathan G [Department of Radiation Oncology, University of Florida, Gainesville, FL 32610-0385 (United States)
2008-04-21
The purpose of this study was to choose an appropriate head scatter source model for the fast and accurate independent planar dose calculation for intensity-modulated radiation therapy (IMRT) with MLC. The performance of three different head scatter source models regarding their ability to model head scatter and facilitate planar dose calculation was evaluated. A three-source model, a two-source model and a single-source model were compared in this study. In the planar dose calculation algorithm, in-air fluence distribution was derived from each of the head scatter source models while considering the combination of Jaw and MLC opening. Fluence perturbations due to tongue-and-groove effect, rounded leaf end and leaf transmission were taken into account explicitly. The dose distribution was calculated by convolving the in-air fluence distribution with an experimentally determined pencil-beam kernel. The results were compared with measurements using a diode array and passing rates with 2%/2 mm and 3%/3 mm criteria were reported. It was found that the two-source model achieved the best agreement on head scatter factor calculation. The three-source model and single-source model underestimated head scatter factors for certain symmetric rectangular fields and asymmetric fields, but similar good agreement could be achieved when monitor back scatter effect was incorporated explicitly. All the three source models resulted in comparable average passing rates (>97%) when the 3%/3 mm criterion was selected. The calculation with the single-source model and two-source model was slightly faster than the three-source model due to their simplicity.
Is it worth to calculate the dose of radioiodine?
International Nuclear Information System (INIS)
Mikalauskas, V.; Kuprionis, G.; Vajauskas, D.
2005-01-01
Full text: Administration of empirical doses of radioiodine (RAI) has been preferred to calculated doses in many hospitals, because the need to measure the size and the iodine uptake in the thyroid involves considerable inconvenience to the patient and additional costs. The preparation of RAI of varying activities also means extra work. Today there is no general consensus on whether radioiodine should be given as a fixed dose or should be calculated. There is also no consensus regarding the question of which radiation burden should be administered to a given volume of thyroid if the activity is calculated. However, while it is possible to deliver a relatively precise dose of radiation to the thyroid gland, maybe it is worth doing this?The aim of this study was to investigate the results of different uptake and volume dependent target doses on clinical outcome of patients with hyperthyroidism in Graves' disease, multi-nodular toxic goiter or toxic adenoma after radioiodine therapy. We reviewed the records of 428 patients (389 women and 39 men, mean age 56.8±12.9 years) who had received radioiodine treatment for Graves' disease and multinodular toxic goiter (n=312) or toxic adenoma (n=116) during the period of 2000-2004 in Kaunas Medical University Hospital. Most patients were given antithyroid drug therapy in order to achieve euthyroidism before treatment with RAI. Radioiodine uptake test with repeated measurements at 2, 6, 24, 48 and/or 72 and/or 96 hr to define the effective half-life was performed. In addition, all the patients underwent thyroid ultrasonography and scintigraphy to define the volume of the thyroid. The 131I activities were calculated according to the formula of Marinelli. In addition to the normal calculation individual target doses were adjusted to the thyroid volumes of each patient before therapy. For statistical evaluation, the patients were divided into four groups: group I included those with a thyroid volume 51 ml. Statistical analysis was
Dose calculation on voxels phantoms using the GEANT4 code
International Nuclear Information System (INIS)
Martins, Maximiano C.; Santos, Denison S.; Queiroz Filho, Pedro P.; Begalli, Marcia
2009-01-01
This work implemented an anthropomorphic phantom of voxels on the structure of Monte Carlo GEANT4, for utilization by professionals from the radioprotection, external dosimetry and medical physics. This phantom allows the source displacement that can be isotropic punctual, plain beam, linear or radioactive gas, in order to obtain diverse irradiation geometries. In them, the radioactive sources exposure is simulated viewing the determination of effective dose or the dose in each organ of the human body. The Zubal head and body trunk phantom was used, and we can differentiate the organs and tissues by the chemical constitution in soft tissue, lung tissue, bone tissue, water and air. The calculation method was validated through the comparison with other well established method, the Visual Monte Carlo (VMC). Besides, a comparison was done with the international recommendation for the evaluation of dose by exposure to punctual sources, described in the document TECDOC - 1162- Generic Procedures for Assessment and Response During a Radiological Emergency, where analytical expressions for this calculation are given. Considerations are made on the validity limits of these expressions for various irradiation geometries, including linear sources, immersion into clouds and contaminated soils
Monte Carlo calculations of patient doses from dental radiography
International Nuclear Information System (INIS)
Gibbs, S.J.; Pujol, A.; Chen, T.S.; Malcolm, A.W.
1984-01-01
A Monte Carlo computer program has been developed to calculate patient dose from diagnostic radiologic procedures. Input data include patient anatomy as serial CT scans at 1-cm intervals from a typical cadaver, beam spectrum, and projection geometry. The program tracks single photons, accounting for photoelectric effect, coherent (using atomic form factors) and incoherent (using scatter functions) scatter. Inhomogeneities (bone, teeth, muscle, fat, lung, air cavities, etc.) are accounted for as they are encountered. Dose is accumulated in a three-dimensional array of voxels, corresponding to the CT input. Output consists of isodose curves, doses to specific organs, and effective dose equivalent, H/sub E/, as defined by ICRP. Initial results, from dental bite-wing projections using 90-kVp, half-wave rectified dental spectra, have produced H/sub E/ values ranging from 3 to 17 microsieverts (0.3-1.7 mrem) per image, depending on image receptor and projection geometry. The probability of stochastic effect is estimated by ICRP as 10/sup -2//Sv, or about 10/sup -7/ to 10/sup -8/ per image
Measurements and calculations of doses from radioactive particles
International Nuclear Information System (INIS)
Leroux, J.B.; Herbaut, Y.
1996-01-01
Three Mile Island (TMI) and Tchernobyl reactor accidents have revealed the importance of the skin exposure to beta radiation produced by small high activity sources, named 'hot particles'. In nuclear power reactors, they may arise as small fragments of irradiated fuel or material which have been neutron activated by passing through the reactor co. In recent years, skin exposure to hot particles has been subject to different limitation criteria, formulated by AIEA, ICRP, NCRP working groups. The present work is the contribution of CEA Grenoble to a contract of the Commission of the European communities in cooperation with several laboratories: University of Birmingham, University of Toulouse and University of Montpellier with the main goal to check experiments and calculations of tissue dose from 60 Co radioactive particles. This report is split up into two parts: hot particle dosimetry close to a 60 Co spherical sample with an approximately 200 μm diameter, using a PTW extrapolation chamber model 233991; dose calculations from two codes: the Varskin Mod 2 computer code and the Hot 25 S2 Monte Carlo algorithm. The two codes lead to similar results; nevertheless there is a large discrepancy (of about 2) between calculations and PTW measurements which are higher by a factor of 1.9. At a 70 μm skin depth and for 1 cm 2 irradiated area, the total (β + γ) tissue dose rate delivered by a spherical ( φ = 200 μm) 60 Co source, in contact with skin, is of the order of 6.1 10 -2 nGy s -1 Bq -1 . (author)
Deterministic calculations of radiation doses from brachytherapy seeds
International Nuclear Information System (INIS)
Reis, Sergio Carneiro dos; Vasconcelos, Vanderley de; Santos, Ana Maria Matildes dos
2009-01-01
Brachytherapy is used for treating certain types of cancer by inserting radioactive sources into tumours. CDTN/CNEN is developing brachytherapy seeds to be used mainly in prostate cancer treatment. Dose calculations play a very significant role in the characterization of the developed seeds. The current state-of-the-art of computation dosimetry relies on Monte Carlo methods using, for instance, MCNP codes. However, deterministic calculations have some advantages, as, for example, short computer time to find solutions. This paper presents a software developed to calculate doses in a two-dimensional space surrounding the seed, using a deterministic algorithm. The analysed seeds consist of capsules similar to IMC6711 (OncoSeed), that are commercially available. The exposure rates and absorbed doses are computed using the Sievert integral and the Meisberger third order polynomial, respectively. The software also allows the isodose visualization at the surface plan. The user can choose between four different radionuclides ( 192 Ir, 198 Au, 137 Cs and 60 Co). He also have to enter as input data: the exposure rate constant; the source activity; the active length of the source; the number of segments in which the source will be divided; the total source length; the source diameter; and the actual and effective source thickness. The computed results were benchmarked against results from literature and developed software will be used to support the characterization process of the source that is being developed at CDTN. The software was implemented using Borland Delphi in Windows environment and is an alternative to Monte Carlo based codes. (author)
Energy Technology Data Exchange (ETDEWEB)
Wong, Jeffrey Y.C., E-mail: jwong@coh.org [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, California (United States); Forman, Stephen; Somlo, George [Department of Hematology/Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, California (United States); Rosenthal, Joseph [Department of Hematology/Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, California (United States); Department of Pediatrics, City of Hope National Medical Center, Duarte, California (United States); Liu An; Schultheiss, Timothy; Radany, Eric [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, California (United States); Palmer, Joycelynne [Department of Biostatistics, City of Hope National Medical Center, Duarte, California (United States); Stein, Anthony [Department of Hematology/Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, California (United States)
2013-01-01
Purpose: We have demonstrated that toxicities are acceptable with total marrow irradiation (TMI) at 16 Gy without chemotherapy or TMI at 12 Gy and the reduced intensity regimen of fludarabine/melphalan in patients undergoing hematopoietic cell transplantation (HCT). This article reports results of a study of TMI combined with higher intensity chemotherapy regimens in 2 phase I trials in patients with advanced acute myelogenous leukemia or acute lymphoblastic leukemia (AML/ALL) who would do poorly on standard intent-to-cure HCT regimens. Methods and Materials: Trial 1 consisted of TMI on Days -10 to -6, etoposide (VP16) on Day -5 (60 mg/kg), and cyclophosphamide (CY) on Day -3 (100 mg/kg). TMI dose was 12 (n=3 patients), 13.5 (n=3 patients), and 15 (n=6 patients) Gy at 1.5 Gy twice daily. Trial 2 consisted of busulfan (BU) on Days -12 to -8 (800 {mu}M min), TMI on Days -8 to -4, and VP16 on Day -3 (30 mg/kg). TMI dose was 12 (n=18) and 13.5 (n=2) Gy at 1.5 Gy twice daily. Results: Trial 1 had 12 patients with a median age of 33 years. Six patients had induction failures (IF), and 6 had first relapses (1RL), 9 with leukemia blast involvement of bone marrow ranging from 10%-98%, 5 with circulating blasts (24%-85%), and 2 with chloromas. No dose-limiting toxicities were observed. Eleven patients achieved complete remission at Day 30. With a median follow-up of 14.75 months, 5 patients remained in complete remission from 13.5-37.7 months. Trial 2 had 20 patients with a median age of 41 years. Thirteen patients had IF, and 5 had 1RL, 2 in second relapse, 19 with marrow blasts (3%-100%) and 13 with peripheral blasts (6%-63%). Grade 4 dose-limiting toxicities were seen at 13.5 Gy (stomatitis and hepatotoxicity). Stomatitis was the most frequent toxicity in both trials. Conclusions: TMI dose escalation to 15 Gy is possible when combined with CY/VP16 and is associated with acceptable toxicities and encouraging outcomes. TMI dose escalation is not possible with BU/VP16 due to
Mathematical models for calculating radiation dose to the fetus
International Nuclear Information System (INIS)
Watson, E.E.
1992-01-01
Estimates of radiation dose from radionuclides inside the body are calculated on the basis of energy deposition in mathematical models representing the organs and tissues of the human body. Complex models may be used with radiation transport codes to calculate the fraction of emitted energy that is absorbed in a target tissue even at a distance from the source. Other models may be simple geometric shapes for which absorbed fractions of energy have already been calculated. Models of Reference Man, the 15-year-old (Reference Woman), the 10-year-old, the five-year-old, the one-year-old, and the newborn have been developed and used for calculating specific absorbed fractions (absorbed fractions of energy per unit mass) for several different photon energies and many different source-target combinations. The Reference woman model is adequate for calculating energy deposition in the uterus during the first few weeks of pregnancy. During the course of pregnancy, the embryo/fetus increases rapidly in size and thus requires several models for calculating absorbed fractions. In addition, the increases in size and changes in shape of the uterus and fetus result in the repositioning of the maternal organs and in different geometric relationships among the organs and the fetus. This is especially true of the excretory organs such as the urinary bladder and the various sections of the gastrointestinal tract. Several models have been developed for calculating absorbed fractions of energy in the fetus, including models of the uterus and fetus for each month of pregnancy and complete models of the pregnant woman at the end of each trimester. In this paper, the available models and the appropriate use of each will be discussed. (Author) 19 refs., 7 figs
Comparison between calculation methods of dose rates in gynecologic brachytherapy
International Nuclear Information System (INIS)
Vianello, E.A.; Biaggio, M.F.; D R, M.F.; Almeida, C.E. de
1998-01-01
In treatments with radiations for gynecologic tumors is necessary to evaluate the quality of the results obtained by different calculation methods for the dose rates on the points of clinical interest (A, rectal, vesicle). The present work compares the results obtained by two methods. The Manual Calibration Method (MCM) tri dimensional (Vianello E., et.al. 1998), using orthogonal radiographs for each patient in treatment, and the Theraplan/T P-11 planning system (Thratonics International Limited 1990) this last one verified experimentally (Vianello et.al. 1996). The results show that MCM can be used in the physical-clinical practice with a percentile difference comparable at the computerized programs. (Author)
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
Dose discrepancies in the buildup region and their impact on dose calculations for IMRT fields
International Nuclear Information System (INIS)
Hsu, Shu-Hui; Moran, Jean M.; Chen Yu; Kulasekere, Ravi; Roberson, Peter L.
2010-01-01
Purpose: Dose accuracy in the buildup region for radiotherapy treatment planning suffers from challenges in both measurement and calculation. This study investigates the dosimetry in the buildup region at normal and oblique incidences for open and IMRT fields and assesses the quality of the treatment planning calculations. Methods: This study was divided into three parts. First, percent depth doses and profiles (for 5x5, 10x10, 20x20, and 30x30 cm 2 field sizes at 0 deg., 45 deg., and 70 deg. incidences) were measured in the buildup region in Solid Water using an Attix parallel plate chamber and Kodak XV film, respectively. Second, the parameters in the empirical contamination (EC) term of the convolution/superposition (CVSP) calculation algorithm were fitted based on open field measurements. Finally, seven segmental head-and-neck IMRT fields were measured on a flat phantom geometry and compared to calculations using γ and dose-gradient compensation (C) indices to evaluate the impact of residual discrepancies and to assess the adequacy of the contamination term for IMRT fields. Results: Local deviations between measurements and calculations for open fields were within 1% and 4% in the buildup region for normal and oblique incidences, respectively. The C index with 5%/1 mm criteria for IMRT fields ranged from 89% to 99% and from 96% to 98% at 2 mm and 10 cm depths, respectively. The quality of agreement in the buildup region for open and IMRT fields is comparable to that in nonbuildup regions. Conclusions: The added EC term in CVSP was determined to be adequate for both open and IMRT fields. Due to the dependence of calculation accuracy on (1) EC modeling, (2) internal convolution and density grid sizes, (3) implementation details in the algorithm, and (4) the accuracy of measurements used for treatment planning system commissioning, the authors recommend an evaluation of the accuracy of near-surface dose calculations as a part of treatment planning commissioning.
The internal radiation dose calculations based on Chinese mathematical phantom
International Nuclear Information System (INIS)
Wang Haiyan; Li Junli; Cheng Jianping; Fan Jiajin
2006-01-01
The internal radiation dose calculations built on Chinese facts become more and more important according to the development of nuclear medicine. the MIRD method developed and consummated by the society of Nuclear Medicine (America) is based on the European and American mathematical phantom and can't fit Chinese well. The transport of γ-ray in the Chinese mathematical phantom was simulated with Monte Carlo method in programs as MCNP4C. the specific absorbed fraction (Φ) of Chinese were calculated and the Chinese Φ database was created. The results were compared with the recommended values by ORNL. the method was proved correct by the coherence when the target organ was the same with the source organ. Else, the difference was due to the different phantom and the choice of different physical model. (authors)
Bone marrow dosimetry in peptide receptor radionuclide therapy with [177Lu-DOTA0,Tyr3]octreotate
International Nuclear Information System (INIS)
Forrer, Flavio; Krenning, Eric P.; Kooij, Peter P.; Bernard, Bert F.; Bakker, Willem H.; Teunissen, Jaap J.M.; Jong, Marion de; Kwekkeboom, Dik J.; Konijnenberg, Mark; Lom, Kirsten van; Herder, Wouter W. de
2009-01-01
Adequate dosimetry is mandatory for effective and safe peptide receptor radionuclide therapy (PRRT). Besides the kidneys, the bone marrow is a potentially dose-limiting organ. The radiation dose to the bone marrow is usually calculated according to the MIRD scheme, where the accumulated activity in the bone marrow is calculated from the accumulated radioactivity of the radiopharmaceutical in the blood. This may underestimate the absorbed dose since stem cells express somatostatin receptors. We verified the blood-based method by comparing the activity in the blood with the radioactivity in bone marrow aspirates. Also, we evaluated the absorbed cross-dose from the source organs (liver, spleen, kidneys and blood), tumours and the so-called ''remainder of the body'' to the bone marrow. Bone marrow aspirates were drawn in 15 patients after treatment with [ 177 Lu-DOTA 0 ,Tyr 3 ]octreotate. Radioactivity in the bone marrow was compared with radioactivity in the blood drawn simultaneously. The nucleated cell fraction was isolated from the bone marrow aspirate and radioactivity was measured. The absorbed dose to the bone marrow was calculated. The results were correlated to the change in platelet counts 6 weeks after treatment. A strong linear correlation and high agreement between the measured radioactivities in the bone marrow aspirates and in the blood was found (r=0.914, p 177 Lu-DOTA 0 ,Tyr 3 ]octreotate, the radioactivity concentration in the bone marrow is identical to that in the blood; (2) There is no significant binding of the radiopharmaceutical to bone marrow precursor stem cells; (3) The contribution of the cross dose from source organs and tumours to the bone marrow dose is significant; and (4) There is considerable variation in bone marrow absorbed dose between patients. These findings imply that for individual dose optimization, individual calculation of the bone marrow absorbed dose is necessary. (orig.)
Independent calculation-based verification of IMRT plans using a 3D dose-calculation engine
International Nuclear Information System (INIS)
Arumugam, Sankar; Xing, Aitang; Goozee, Gary; Holloway, Lois
2013-01-01
Independent monitor unit verification of intensity-modulated radiation therapy (IMRT) plans requires detailed 3-dimensional (3D) dose verification. The aim of this study was to investigate using a 3D dose engine in a second commercial treatment planning system (TPS) for this task, facilitated by in-house software. Our department has XiO and Pinnacle TPSs, both with IMRT planning capability and modeled for an Elekta-Synergy 6 MV photon beam. These systems allow the transfer of computed tomography (CT) data and RT structures between them but do not allow IMRT plans to be transferred. To provide this connectivity, an in-house computer programme was developed to convert radiation therapy prescription (RTP) files as generated by many planning systems into either XiO or Pinnacle IMRT file formats. Utilization of the technique and software was assessed by transferring 14 IMRT plans from XiO and Pinnacle onto the other system and performing 3D dose verification. The accuracy of the conversion process was checked by comparing the 3D dose matrices and dose volume histograms (DVHs) of structures for the recalculated plan on the same system. The developed software successfully transferred IMRT plans generated by 1 planning system into the other. Comparison of planning target volume (TV) DVHs for the original and recalculated plans showed good agreement; a maximum difference of 2% in mean dose, − 2.5% in D95, and 2.9% in V95 was observed. Similarly, a DVH comparison of organs at risk showed a maximum difference of +7.7% between the original and recalculated plans for structures in both high- and medium-dose regions. However, for structures in low-dose regions (less than 15% of prescription dose) a difference in mean dose up to +21.1% was observed between XiO and Pinnacle calculations. A dose matrix comparison of original and recalculated plans in XiO and Pinnacle TPSs was performed using gamma analysis with 3%/3 mm criteria. The mean and standard deviation of pixels passing
Conceptual basis for calculations of absorbed-dose distributions
International Nuclear Information System (INIS)
Sinclair, W.K.; Rossi, H.H.; Alsmiller, R.G.; Berger, M.J.; Kellerer, A.M.; Roesch, W.C.; Spencer, L.V.; Zaider, M.A.
1991-01-01
The effects of radiation on matter are initiated by processes in which atoms and molecules of the medium are ionized or excited. Over a wide range of conditions, it is an excellent approximation to assume that the average number of ionizations and excitations is proportional to the amount of energy imparted to the medium by ionizing radiation in the volume of interest. The absorbed dose, that is, the average amount of energy imparted to the medium per unit mass, is therefore of central importance for the production of radiation effects, and the calculation of absorbed-dose distributions in irradiated media is the focus of interest of the present report. It should be pointed out, however, that even though absorbed dose is useful as an index relating absorbed energy to radiation effects, it is almost never sufficient; it may have to be supplemented by other information, such as the distributions of the amounts of energy imparted to small sites, the correlation of the amounts of energy imparted to adjacent sites, and so on. Such quantities are termed stochastic quantities. Unless otherwise stated, all quantities considered in this report are non-stochastic. 266 refs., 11 figs., 2 tabs
Assessing the effect of electron density in photon dose calculations
International Nuclear Information System (INIS)
Seco, J.; Evans, P. M.
2006-01-01
Photon dose calculation algorithms (such as the pencil beam and collapsed cone, CC) model the attenuation of a primary photon beam in media other than water, by using pathlength scaling based on the relative mass density of the media to water. In this study, we assess if differences in the electron density between the water and media, with different atomic composition, can influence the accuracy of conventional photon dose calculations algorithms. A comparison is performed between an electron-density scaling method and the standard mass-density scaling method for (i) tissues present in the human body (such as bone, muscle, etc.), and for (ii) water-equivalent plastics, used in radiotherapy dosimetry and quality assurance. We demonstrate that the important material property that should be taken into account by photon dose algorithms is the electron density, and not the mass density. The mass-density scaling method is shown to overestimate, relative to electron-density predictions, the primary photon fluence for tissues in the human body and water-equivalent plastics, where 6%-7% and 10% differences were observed respectively for bone and air. However, in the case of patients, differences are expected to be smaller due to the large complexity of a treatment plan and of the patient anatomy and atomic composition and of the smaller thickness of bone/air that incident photon beams of a treatment plan may have to traverse. Differences have also been observed for conventional dose algorithms, such as CC, where an overestimate of the lung dose occurs, when irradiating lung tumors. The incorrect lung dose can be attributed to the incorrect modeling of the photon beam attenuation through the rib cage (thickness of 2-3 cm in bone upstream of the lung tumor) and through the lung and the oversimplified modeling of electron transport in convolution algorithms. In the present study, the overestimation of the primary photon fluence, using the mass-density scaling method, was shown
Implementation of spot scanning dose optimization and dose calculation for helium ions in Hyperion
Energy Technology Data Exchange (ETDEWEB)
Fuchs, Hermann, E-mail: hermann.fuchs@meduniwien.ac.at [Department of Radiation Oncology, Division of Medical Radiation Physics, Medical University of Vienna/AKH Vienna, Vienna 1090, Austria and Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna 1090 (Austria); Alber, Markus [Department for Oncology, Aarhus University Hospital, Aarhus 8000 (Denmark); Schreiner, Thomas [PEG MedAustron, Wiener Neustadt 2700 (Austria); Georg, Dietmar [Department of Radiation Oncology, Division of Medical Radiation Physics, Medical University of Vienna/AKH Vienna, Vienna 1090 (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna 1090 (Austria); Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, Vienna 1090 (Austria)
2015-09-15
Purpose: Helium ions ({sup 4}He) may supplement current particle beam therapy strategies as they possess advantages in physical dose distribution over protons. To assess potential clinical advantages, a dose calculation module accounting for relative biological effectiveness (RBE) was developed and integrated into the treatment planning system Hyperion. Methods: Current knowledge on RBE of {sup 4}He together with linear energy transfer considerations motivated an empirical depth-dependent “zonal” RBE model. In the plateau region, a RBE of 1.0 was assumed, followed by an increasing RBE up to 2.8 at the Bragg-peak region, which was then kept constant over the fragmentation tail. To account for a variable proton RBE, the same model concept was also applied to protons with a maximum RBE of 1.6. Both RBE models were added to a previously developed pencil beam algorithm for physical dose calculation and included into the treatment planning system Hyperion. The implementation was validated against Monte Carlo simulations within a water phantom using γ-index evaluation. The potential benefits of {sup 4}He based treatment plans were explored in a preliminary treatment planning comparison (against protons) for four treatment sites, i.e., a prostate, a base-of-skull, a pediatric, and a head-and-neck tumor case. Separate treatment plans taking into account physical dose calculation only or using biological modeling were created for protons and {sup 4}He. Results: Comparison of Monte Carlo and Hyperion calculated doses resulted in a γ{sub mean} of 0.3, with 3.4% of the values above 1 and γ{sub 1%} of 1.5 and better. Treatment plan evaluation showed comparable planning target volume coverage for both particles, with slightly increased coverage for {sup 4}He. Organ at risk (OAR) doses were generally reduced using {sup 4}He, some by more than to 30%. Improvements of {sup 4}He over protons were more pronounced for treatment plans taking biological effects into account. All
The models of internal dose calculation in ICRP
International Nuclear Information System (INIS)
Nakano, Takashi
1995-01-01
There are a lot discussions about internal dose calculation in ICRP. Many efforts are devoted to improvement in models and parameters. In this report, we discuss what kind of models and parameters are used in ICRP. Models are divided into two parts, the dosimetric model and biokinetic model. The former is a mathematical phantom model, and it is mainly developed in ORNL. The results are used in many researchers. The latter is a compartment model and it has a difficulty to decide the parameter values. They are not easy to estimate because of their age dependency. ICRP officially sets values at ages of 3 month, 1 year, 5 year, 10 year, 15 year and adult, and recommends to get values among ages by linear age interpolate. But it is very difficult to solve the basic equation with these values, so we calculate by use of computers. However, it has complex shame and needs long CPU time. We should make approximated equations. The parameter values include much uncertainty because of less experimental data, especially for a child. And these models and parameter values are for Caucasian. We should inquire whether they could correctly describe other than Caucasian. The body size affects the values of calculated SAF, and the differences of metabolism change the biokinetic pattern. (author)
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
International Nuclear Information System (INIS)
Strenge, D.L.; Peloquin, R.A.
1981-04-01
The computer code HADOC (Hanford Acute Dose Calculations) is described and instructions for its use are presented. The code calculates external dose from air submersion and inhalation doses following acute radionuclide releases. Atmospheric dispersion is calculated using the Hanford model with options to determine maximum conditions. Building wake effects and terrain variation may also be considered. Doses are calculated using dose conversion factor supplied in a data library. Doses are reported for one and fifty year dose commitment periods for the maximum individual and the regional population (within 50 miles). The fractional contribution to dose by radionuclide and exposure mode are also printed if requested
Energy Technology Data Exchange (ETDEWEB)
Greenberger, J S [Joint Center for Radiation Therapy, Department of Radiation and Sidney Farber Cancer Institute; Chang, J M; King, V; Fulmer, S; Balzuno, S; Moloney, W C [Division of Hematology, Department of Medicine, Brigham and Women' s Hospital Harvard Medical School, Boston, USA
1981-01-01
Bone marrow from each of 8 untreated patients with myeloproliferative disorders was grown in diffusion chambers in 760 rad total body irradiated rats. Rats were exposed to 11.5, 57.5, or 108.5 rad daily for 14-21 and cell growth compared to that detected in unirradiated chambers. Cells from acute myelogenous leukaemia patients exposed to 11.5 rad per d grew for 11-21 d and there was no consistent stimulation of differentiation of immature granulocytic cells to mature granulocytes that was attributable to irradiation. Cells from a chronic myeloid leukaemia patient in chronic phase or blast crisis, and a polycythaemia vera patient with myeloid metaplasia showed signigicant morphologic differentiation from immature to mature granulocytes in control chambers with no additional effect of daily irradiation. Marrow specimens from 2 AML patients exposed to each of 3 daily dose fractions over 14 d revealed a dose-dependent decrease in immature granulocytes with no persistent increase in mature granulocytes. In both irradiated and control chambers, macrophages increased over 21 d. Thus, cells from patients with myeloprofilerative disorders may not necessarily differentiate to mature granulocytes following in vivo exposure to ionizing irradiation.
International Nuclear Information System (INIS)
Hongo, Shozo; Yamaguchi, Hiroshi; Takeshita, Hiroshi; Iwai, Satoshi.
1994-01-01
A computer program named IDES is developed by BASIC language for a personal computer and translated to C language of engineering work station. The IDES carries out internal dose calculations described in ICRP Publication 30 and it installs the program of transformation method which is an empirical method to estimate absorbed fractions of different physiques from ICRP Referenceman. The program consists of three tasks: productions of SAF for Japanese including children, productions of SEE, Specific Effective Energy, and calculation of effective dose equivalents. Each task and corresponding data file appear as a module so as to meet future requirement for revisions of the related data. Usefulness of IDES is discussed by exemplifying the case that 5 age groups of Japanese intake orally Co-60 or Mn-54. (author)
Stimulating effect of low dose radiation expression of G-CSF receptors in bone marrow cells in mice
International Nuclear Information System (INIS)
Zhang Honglai; Liu Shuzheng; Zhang Ming
1993-01-01
The expression of G-CSF receptors in bone marrow cells (BMC) was studied by using 125 I labelled G-CSF ( 1 '2 5 I-G-CSF). The results showed that the reaction equilibrium of 125 I-G-CSF bound to BMC at 37 degree C was reached in 60 minutes, the maximum binding (Bmax) to 3 x 10 6 BMC being 15.1 pmol, the dissociation constant (Kd) being 78.6 pmol, and the estimated number of G-CSF receptors per cell being about 3100. The number of G-CSF receptors in BMC in mice 48 hours after whole body exposure to doses of 50, 75 and 100 mGy X-rays increased significantly to 161%, 169% and 342% of controls, respectively. The results suggested that the expression of G-CSF receptors in BMC was enhanced markedly following low dose radiation, which would lead to stimulation of BMC proliferation
International Nuclear Information System (INIS)
Xiang Yingsong; Yang Rujun; Tang Gusheng
2001-01-01
Objective: To investigate the characterization of death of the human hematopoietic stem cells after irradiation. Methods: Human fetal bone marrow mononuclear cells were irradiated with different doses of 60 Co γ-rays at different high dose rates. Apoptosis and necrosis of CD34 + cells were analyzed by flow cytometry, following three-color labelling with PE-CD34/FITC-Annexin V/7AAD at different times after irradiation. Results: The death of CD34 + cells after 5 Gy and 8 Gy irradiation showed a continuous process of reproductive death during the first week,and the main death type was apoptosis. A majority of CD34 + cells died of necrosis during the first day after 10 Gy and 12 Gy irradiation, and all of them died within a week. Conclusion: Niches are continuously vacated every day within a week following irradiation and reproductive death of hematopoietic stem cells occurred
International Nuclear Information System (INIS)
Cormack, J.; Shearer, J.
2000-01-01
Full text: For nuclear medicine patients who are breast feeding an infant, special radiation safety precautions may need to be taken. An estimate of the potential radiation dose to the child from ingested milk must be made, and breast-feeding may need to be suspended until levels of radioactivity in the breast-milk have fallen to acceptable levels. The risk of radiation to the child must be weighed against the benefits of breast-feeding and the possible trauma to both mother and child arising from interruption or cessation of the milk supply. In the United States, the Nuclear Regulatory Commission (NRC) has already published regulations which will necessitate an estimate of the infant's dose from breast milk to be made, in principle, for every breast-feeding patient. There is obviously, therefore, a need to provide a rapid and reliable means of estimating such doses. A spreadsheet template which automatically calculates the cumulative dose to breast feeding infants based on any multi-exponential clearance of activity from the breast milk, and any pattern of feeding, has been developed by the authors. The time (post administration) for which breast-feeding should be interrupted in order to constrain the radiation dose to a selected limit is also calculated along with the concentration of activity in breast milk at which feeding can resume. The effect of changing dose limits, feeding patterns and using individually derived breast milk clearance rates may be readily modelled using this spreadsheet template. Data has been included for many of the most commonly used radiopharmaceuticals and new data can readily be incorporated as it becomes available. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc
Considerations of beta and electron transport in internal dose calculations
International Nuclear Information System (INIS)
Bolch, W.E.; Poston, J.W. Sr.
1990-12-01
Ionizing radiation has broad uses in modern science and medicine. These uses often require the calculation of energy deposition in the irradiated media and, usually, the medium of interest is the human body. Energy deposition from radioactive sources within the human body and the effects of such deposition are considered in the field of internal dosimetry. In July of 1988, a three-year research project was initiated by the Nuclear Engineering Department at Texas A ampersand M University under the sponsorship of the US Department of Energy. The main thrust of the research was to consider, for the first time, the detailed spatial transport of electron and beta particles in the estimation of average organ doses under the Medical Internal Radiation Dose (MIRD) schema. At the present time (December of 1990), research activities are continuing within five areas. Several are new initiatives begun within the second or third year of the current contract period. They include: (1) development of small-scale dosimetry; (2) development of a differential volume phantom; (3) development of a dosimetric bone model; (4) assessment of the new ICRP lung model; and (5) studies into the mechanisms of DNA damage. A progress report is given for each of these tasks within the Comprehensive Report. In each use, preliminary results are very encouraging and plans for further research are detailed within this document. 22 refs., 13 figs., 1 tab
Considerations of beta and electron transport in internal dose calculations
Energy Technology Data Exchange (ETDEWEB)
Bolch, W.E.; Poston, J.W. Sr.
1990-12-01
Ionizing radiation has broad uses in modern science and medicine. These uses often require the calculation of energy deposition in the irradiated media and, usually, the medium of interest is the human body. Energy deposition from radioactive sources within the human body and the effects of such deposition are considered in the field of internal dosimetry. In July of 1988, a three-year research project was initiated by the Nuclear Engineering Department at Texas A M University under the sponsorship of the US Department of Energy. The main thrust of the research was to consider, for the first time, the detailed spatial transport of electron and beta particles in the estimation of average organ doses under the Medical Internal Radiation Dose (MIRD) schema. At the present time (December of 1990), research activities are continuing within five areas. Several are new initiatives begun within the second or third year of the current contract period. They include: (1) development of small-scale dosimetry; (2) development of a differential volume phantom; (3) development of a dosimetric bone model; (4) assessment of the new ICRP lung model; and (5) studies into the mechanisms of DNA damage. A progress report is given for each of these tasks within the Comprehensive Report. In each case, preliminary results are very encouraging and plans for further research are detailed within this document.
Considerations of beta and electron transport in internal dose calculations
Energy Technology Data Exchange (ETDEWEB)
Bolch, W.E.; Poston, J.W. Sr. (Texas A and M Univ., College Station, TX (USA). Dept. of Nuclear Engineering)
1990-12-01
Ionizing radiation has broad uses in modern science and medicine. These uses often require the calculation of energy deposition in the irradiated media and, usually, the medium of interest is the human body. Energy deposition from radioactive sources within the human body and the effects of such deposition are considered in the field of internal dosimetry. In July of 1988, a three-year research project was initiated by the Nuclear Engineering Department at Texas A M University under the sponsorship of the US Department of Energy. The main thrust of the research was to consider, for the first time, the detailed spatial transport of electron and beta particles in the estimation of average organ doses under the Medical Internal Radiation Dose (MIRD) schema. At the present time (December of 1990), research activities are continuing within five areas. Several are new initiatives begun within the second or third year of the current contract period. They include: (1) development of small-scale dosimetry; (2) development of a differential volume phantom; (3) development of a dosimetric bone model; (4) assessment of the new ICRP lung model; and (5) studies into the mechanisms of DNA damage. A progress report is given for each of these tasks within the Comprehensive Report. In each use, preliminary results are very encouraging and plans for further research are detailed within this document. 22 refs., 13 figs., 1 tab.
Considerations of beta and electron transport in internal dose calculations
International Nuclear Information System (INIS)
Bolch, W.E.; Poston, J.W. Sr.
1990-12-01
Ionizing radiation has broad uses in modern science and medicine. These uses often require the calculation of energy deposition in the irradiated media and, usually, the medium of interest is the human body. Energy deposition from radioactive sources within the human body and the effects of such deposition are considered in the field of internal dosimetry. In July of 1988, a three-year research project was initiated by the Nuclear Engineering Department at Texas A ampersand M University under the sponsorship of the US Department of Energy. The main thrust of the research was to consider, for the first time, the detailed spatial transport of electron and beta particles in the estimation of average organ doses under the Medical Internal Radiation Dose (MIRD) schema. At the present time (December of 1990), research activities are continuing within five areas. Several are new initiatives begun within the second or third year of the current contract period. They include: (1) development of small-scale dosimetry; (2) development of a differential volume phantom; (3) development of a dosimetric bone model; (4) assessment of the new ICRP lung model; and (5) studies into the mechanisms of DNA damage. A progress report is given for each of these tasks within the Comprehensive Report. In each case, preliminary results are very encouraging and plans for further research are detailed within this document
Emergency Doses (ED) - Revision 3: A calculator code for environmental dose computations
International Nuclear Information System (INIS)
Rittmann, P.D.
1990-12-01
The calculator program ED (Emergency Doses) was developed from several HP-41CV calculator programs documented in the report Seven Health Physics Calculator Programs for the HP-41CV, RHO-HS-ST-5P (Rittman 1984). The program was developed to enable estimates of offsite impacts more rapidly and reliably than was possible with the software available for emergency response at that time. The ED - Revision 3, documented in this report, revises the inhalation dose model to match that of ICRP 30, and adds the simple estimates for air concentration downwind from a chemical release. In addition, the method for calculating the Pasquill dispersion parameters was revised to match the GENII code within the limitations of a hand-held calculator (e.g., plume rise and building wake effects are not included). The summary report generator for printed output, which had been present in the code from the original version, was eliminated in Revision 3 to make room for the dispersion model, the chemical release portion, and the methods of looping back to an input menu until there is no further no change. This program runs on the Hewlett-Packard programmable calculators known as the HP-41CV and the HP-41CX. The documentation for ED - Revision 3 includes a guide for users, sample problems, detailed verification tests and results, model descriptions, code description (with program listing), and independent peer review. This software is intended to be used by individuals with some training in the use of air transport models. There are some user inputs that require intelligent application of the model to the actual conditions of the accident. The results calculated using ED - Revision 3 are only correct to the extent allowed by the mathematical models. 9 refs., 36 tabs
Dant, James T.; Richardson, Richard B.; Nie, Linda H.
2013-05-01
Alpha (α) particles and low-energy beta (β) particles present minimal risk for external exposure. While these particles can induce leukemia and bone cancer due to internal exposure, they can also be beneficial for targeted radiation therapies. In this paper, a trabecular bone model is presented to investigate the radiation dose from bone- and marrow-seeking α and β emitters to different critical compartments (targets) of trabecular bone for different age groups. Two main issues are addressed with Monte Carlo simulations. The first is the absorption fractions (AFs) from bone and marrow to critical targets within the bone for different age groups. The other issue is the application of 223Ra for the radiotherapy treatment of bone metastases. Both a static model and a simulated bone remodeling process are established for trabecular bone. The results show significantly lower AFs from radionuclide sources in the bone volume to the peripheral marrow and the haematopoietic marrow for adults than for newborns and children. The AFs from sources on the bone surface and in the bone marrow to peripheral marrow and haematopoietic marrow also varies for adults and children depending on the energy of the particles. Regarding the use of 223Ra as a radionuclide for the radiotherapy of bone metastases, the simulations show a significantly higher dose from 223Ra and its progeny in forming bone to the target compartment of bone metastases than that from two other more commonly used β-emitting radiopharmaceuticals, 153Sm and 89Sr. There is also a slightly lower dose from 223Ra in forming bone to haematopoietic marrow than that from 153Sm and 89Sr. These results indicate a higher therapy efficiency and lower marrow toxicity from 223Ra and its progeny. In conclusion, age-related changes in bone dimension and cellularity seem to significantly affect the internal dose from α and β emitters in the bone and marrow to critical targets, and 223Ra may be a more efficient
International Nuclear Information System (INIS)
Thalhofer, J. L.; Marques L, J.; Da Silva, A. X.; Dos Reis J, J. P.; Da Silva J, W. F. R.; Arruda C, S. C.; Monteiro de S, E.; Santos B, D. V.
2017-10-01
Actually, lung cancer is one of the most lethal types, due to the disease in the majority of the cases asymptomatic in the early stages, being the detection of the pathology in advanced stage, with tumor considerable volume. Dosimetry analysis of healthy organs under real conditions is not feasible. Therefore, computational simulations are used to auxiliary in dose verification in organs of patients submitted to radiotherapy. The goal of this study is to calculate the equivalent dose, due to photons, in surrounding in healthy organs of a patient submitted to radiotherapy for lung cancer, through computational modeling. The simulation was performed using the MCNPX code (Version, 2006], Rex and Regina phantom [ICRP 110, 2008], radiotherapy room, Siemens Oncor Expression accelerator operating at 6 MV and treatment protocol adopted at the Inca (National Cancer Institute, Brazil). The results obtained, considering the dose due to photons for both phantom indicate that organs located inside the thoracic cavity received higher dose, being the bronchi, heart and esophagus more affected, due to the anatomical positioning. Clinical data describe the development of bronchiolitis, esophagitis, and cardiomyopathies with decreased cardiopulmonary function as one of the major effects of lung cancer treatment. In the Regina phantom, the second largest dose was in the region of the breasts with 615,73 mSv / Gy, while in the Rex 514,06 mSv / Gy, event related to the difference of anatomical structure of the organ. Through the t mesh command, a qualitative analysis was performed between the dose deposition profile of the planning system and the simulated treatment, with a similar profile of the dose distribution being verified along the patients body. (Author)
International Nuclear Information System (INIS)
Defresne, M.P.; Greimers, R.; Lenaerts, P.; Boniver, J.
1986-01-01
A split-dose regimen of whole-body irradiation (4 X 175 rad at weekly intervals) induced thymic lymphomas in C57BL/Ka mice after a latent period of 3-9 months. Meanwhile, preleukemia cells arose in the thymus and bone marrow and persisted until the onset of lymphomas. Simultaneously, thymic lymphopoiesis was impaired; thymocyte numbers were subnormal and thymic nurse cells disappeared in a progressive but irreversible fashion. The depletion of these lymphoepithelial complexes, which are normally involved in the early steps of thymic lymphopoiesis, was related to altered prothymocyte activity in bone marrow and to damaged thymic microenvironment, perhaps as a consequence of the presence of preleukemia cells. The grafting of normal bone marrow cells after irradiation prevented the development of lymphomas. However, marrow reconstitution did not inhibit the induction of preleukemia cells. They disappeared from the thymus during the second part of the latent period. At the same time, thymic lymphopoiesis was restored; thymocytes and nurse cell numbers returned to normal as a consequence of the proliferation of grafted marrow-derived cells within the thymus. The results thus demonstrated an intimate relationship between preleukemia cells and an alteration of thymic lymphopoiesis, which particularly involved the nurse cell microenvironment. Some preleukemia cells in marrow-reconstituted, irradiated mice derived from the unirradiated marrow inoculate. Thus these cells acquired neoplastic potential through a factor present in the irradiated tissues. The nature of this indirect mechanism was briefly discussed
Energy Technology Data Exchange (ETDEWEB)
None, None
2017-05-01
Operations of Sandia National Laboratories, Nevada (SNL/NV) at the Tonopah Test Range (TTR) resulted in no planned point radiological releases during 1996. Other releases from SNL/NV included diffuse transuranic sources consisting of the three Clean Slate sites. Air emissions from these sources result from wind resuspension of near-surface transuranic contaminated soil particulates. The total area of contamination has been estimated to exceed 20 million square meters. Soil contamination was documented in an aerial survey program in 1977 (EG&G 1979). Surface contamination levels were generally found to be below 400 pCi/g of combined plutonium-238, plutonium-239, plutonium-240, and americium-241 (i.e., transuranic) activity. Hot spot areas contain up to 43,000 pCi/g of transuranic activity. Recent measurements confirm the presence of significant levels of transuranic activity in the surface soil. An annual diffuse source term of 0.39 Ci of transuranic material was calculated for the cumulative release from all three Clean Slate sites. A maximally exposed individual dose of 1.1 mrem/yr at the TTR airport area was estimated based on the 1996 diffuse source release amounts and site-specific meteorological data. A population dose of 0.86 person-rem/yr was calculated for the local residents. Both dose values were attributable to inhalation of transuranic contaminated dust.
International Nuclear Information System (INIS)
Matsue, K.; Niki, T.; Shiobara, S.; Ueda, M.; Ohtake, S.; Mori, T.; Matsuda, T.; Harada, M.
1990-01-01
We describe the clinical course of a 16 year old girl with aplastic anemia who was treated by syngeneic bone marrow transplantation. Engraftment was not obtained by simple infusion of bone marrow without immunosuppression. The patient received a high-dose cyclophosphamide and thoracoabdominal irradiation, followed by second marrow transplantation from the same donor. Incomplete but significant hematologic recovery was observed; however, marrow failure recurred 5 months after transplantation. Since donor and recipient pairs were genotypically identical, graft failure could not be attributed to immunological reactivity of recipient cells to donor non-HLA antigens. This case report implies that graft failure in some cases of aplastic anemia might be mediated by inhibitory cells resistant to cyclophosphamide and irradiation
International Nuclear Information System (INIS)
Pillinger, W.L.; Marter, W.L.
1982-01-01
Standardized dose constants are recommended for calculation of offsite doses in the 1982 SRP Reactor Safety Analysis Report (SAR). Dose constants are proposed for inhalation of tritium and radioiodines and for submersion in a semi-infinite cloud of radioiodines and noble gases. The proposed constants, based on ICRP2 methodology for internal dose and methodology recommended by the US Nuclear Regulatory Commission for external dose, are compatible with dose calculational methods used at the Savannah River Plant and Savannah River Laboratory for normal releases of radioactivity. 8 references
International Nuclear Information System (INIS)
Esteve Sanchez, S.; Martinez Albaladejo, M.; Garcia Fuentes, J. D.; Bejar Navarro, M. J.; Capuz Suarez, B.; Moris de Pablos, R.; Colmenares Fernandez, R.
2015-01-01
We assessed the reliability of the program with 80 patients in the usual points of prescription of each pathology. The average error of the calculation points is less than 0.3% in 95% of cases, finding the major differences in the axes of the applicators (maximum error -0.798%). The program has proved effective previously testing him with erroneous dosimetry. Thanks to the implementation of this program is achieved by the calculation of the dose and part of the process of quality assurance program in a few minutes, highlighting the case of HDR prostate due to having a limited time. Having separate data sheet allows each institution to its protocols modify parameters. (Author)
Directory of Open Access Journals (Sweden)
Bo Huang
2015-01-01
Full Text Available Radiation therapy for oral and maxillofacial tumors could damage bone marrow stromal cells (BMSCs in jaw, which caused dental implant failure. However, how radiation affects BMSCs on SLA (sandblasted with large-grits, acid-etched surfaces is still unknown. The aim of this study was to investigate effect of different dose of γ-radiation on BMSCs on SLA and PT (polished titanium surfaces. Rat BMSCs were radiated with 2, 4, and 8 Gy γ-radiation and then seeded on both surfaces. Cell adhesion, spreading, and proliferation were tested. The osteogenesis and the adipogenesis ability were examined by Alizarin-Red and Oil-Red staining, respectively. Real-time PCR was performed to detect osteogenic (osteocalcin, OCN; runt-related transcription factor 2, Runx2 and adipogenic (peroxisome proliferator-activated receptor gamma, PPARγ gene expression at days 7 and 14 postirradiation. Results showed that γ-radiation reduced cell proliferation, adhesion, spreading, and osteogenic differentiation. 2 Gy radiation promoted adipogenic differentiation, but it was significantly decreased when dosage reached 4 Gy. In conclusion, results suggest that γ-radiation influenced BMSCs behaviors in a dosage-dependent manner except adipogenic differentiation, low dose promoted it, and high dose inhibited it. This effect was influenced by surface characteristics, which may explain the different failure rate of various implants in patients after radiation.
Monte Carlo calculation of ''skyshine'' neutron dose from ALS [Advanced Light Source
International Nuclear Information System (INIS)
Moin-Vasiri, M.
1990-06-01
This report discusses the following topics on ''skyshine'' neutron dose from ALS: Sources of radiation; ALS modeling for skyshine calculations; MORSE Monte-Carlo; Implementation of MORSE; Results of skyshine calculations from storage ring; and Comparison of MORSE shielding calculations
Exact comparison of dose rate measurements and calculation of TN12/2 packages
International Nuclear Information System (INIS)
Taniuchi, H.; Matsuda, F.
1998-01-01
Both of dose rate measurements of TN 12/2 package and calculations by Monte Carlo code MORSE in SCALE code system and MCNP were performed to evaluate the difference between the measurement and the calculation and finding out the cause of the difference. The calculated gamma-ray dose rates agreed well with measured ones, but calculated neutron dose rates overestimated more than a factor of 1.7. When considering the cause of the difference and applying the modification into the neutron calculation, the calculated neutron dose rates become to agree well, and the factor decreased to around 1.3. (authors)
International Nuclear Information System (INIS)
2007-08-01
The guide presents the definitions of equivalent dose and effective dose, the principles for calculating these doses, and instructions for applying their maximum values. The limits (Annual Limit on Intake and Derived Air Concentration) derived from dose limits are also presented for the purpose of monitoring exposure to internal radiation. The calculation of radiation doses caused to a patient from medical research and treatment involving exposure to ionizing radiation is beyond the scope of this ST Guide
International Nuclear Information System (INIS)
Yang Yan; Wang Guanjun; Zhu Jingyan; Wang Juan
2008-01-01
Objective: To study the changes of hematopoietic growth factors secreted by human mesenchymal stem cells from bone marrow (BM-MSC) pretreated with low dose radiation (LDR). Methods: The cultured P4 and P5 BM-MSCs were exposed to X rays at the doses of 50, 75 and 100 mGy (dose rate 12.5 mGy·min -1 ). The changes of levels of stem cell factor (SCF), IL-6, macrophage colony-stimulating factor (M-CSF) secreted by BM- MSCs pretreated with LDR were determined by ELISA method. Results: As compared with control group at the same time, the levels of SCF in experimental group had a tendency of increasing after 24 h and 48 h radiation, but only in 75 mGy group the SCF level was obviously increased (P<0.05). The levels of IL-6 in 50 and 75 mGy groups at 24 h and 48 h, in 100 mGy group at 24 h were obviously increased compared with control group (P< 0.05). The levels of M-CSF in all the groups at 24 h, 48 h and 72 h except for the 50 mGy dose at 72 h were also increased (P<0.05), it increased markedly in 75 mGy dose group at 72 h. Conclusion: LDR has hormesis effect on BM-MSCs. After LDR, the BM-MSCs grow faster and in a certain phase the expression levels of hematopoietic growth factors are increased. (authors)
International Nuclear Information System (INIS)
Napier, B.A.; Kennedy, W.E. Jr.; Soldat, J.K.
1980-03-01
A computer program, PABLM, was written to facilitate the calculation of internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. This report contains details of mathematical models used and calculational procedures required to run the computer program. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides in the environment after the releases have ended. Radioactive decay is considered during the release of radionuclides, after they are deposited on the plants or ground, and during holdup of food after harvest. The radiation dose models consider several exposure pathways. Doses may be calculated for either a maximum-exposed individual or for a population group. The doses calculated are accumulated doses from continuous chronic exposure. A first-year committed dose is calculated as well as an integrated dose for a selected number of years. The equations for calculating internal radiation doses are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and MPC's of each radionuclide. The radiation doses from external exposure to contaminated water and soil are calculated using the basic assumption that the contaminated medium is large enough to be considered an infinite volume or plane relative to the range of the emitted radiations. The equations for calculations of the radiation dose from external exposure to shoreline sediments include a correction for the finite width of the contaminated beach
SU-F-T-441: Dose Calculation Accuracy in CT Images Reconstructed with Artifact Reduction Algorithm
Energy Technology Data Exchange (ETDEWEB)
Ng, C; Chan, S; Lee, F; Ngan, R [Queen Elizabeth Hospital (Hong Kong); Lee, V [University of Hong Kong, Hong Kong, HK (Hong Kong)
2016-06-15
Purpose: Accuracy of radiotherapy dose calculation in patients with surgical implants is complicated by two factors. First is the accuracy of CT number, second is the dose calculation accuracy. We compared measured dose with dose calculated on CT images reconstructed with FBP and an artifact reduction algorithm (OMAR, Philips) for a phantom with high density inserts. Dose calculation were done with Varian AAA and AcurosXB. Methods: A phantom was constructed with solid water in which 2 titanium or stainless steel rods could be inserted. The phantom was scanned with the Philips Brillance Big Bore CT. Image reconstruction was done with FBP and OMAR. Two 6 MV single field photon plans were constructed for each phantom. Radiochromic films were placed at different locations to measure the dose deposited. One plan has normal incidence on the titanium/steel rods. In the second plan, the beam is at almost glancing incidence on the metal rods. Measurements were then compared with dose calculated with AAA and AcurosXB. Results: The use of OMAR images slightly improved the dose calculation accuracy. The agreement between measured and calculated dose was best with AXB and image reconstructed with OMAR. Dose calculated on titanium phantom has better agreement with measurement. Large discrepancies were seen at points directly above and below the high density inserts. Both AAA and AXB underestimated the dose directly above the metal surface, while overestimated the dose below the metal surface. Doses measured downstream of metal were all within 3% of calculated values. Conclusion: When doing treatment planning for patients with metal implants, care must be taken to acquire correct CT images to improve dose calculation accuracy. Moreover, great discrepancies in measured and calculated dose were observed at metal/tissue interface. Care must be taken in estimating the dose in critical structures that come into contact with metals.
International Nuclear Information System (INIS)
Yu Hongsheng; Fei Conghe; Shen Fangzhen; Liang Jun
2004-01-01
Objective: To study the effect of low dose radiation (LDR) combined with cyclophosphamide on tumor cell apoptosis, cell cycle, and proliferation of bone marrow in mice tumor-bearing mice. Methods: Kunming strain male mice were implanted with S180 sarcoma cells in the left hind leg subcutaneously as an experimental animal model. Five and 8 days after implantation, the mice were given 75 mGy whole-body γ-ray radiation and CTX(300 mg/kg) by intraperitoneal injection 36 hour after LDR. All mice were sacrificed to measure the tumor volume, tumor cell apoptosis, and cell cycle; the proliferation of bone marrow was analyzed by flow cytometry. Results: Tumor growth was significantly slowed down in the treated groups. The apoptosis of tumor cells increased significantly after LDR. The tumor cells were arrested in G 1 phase in CTX and CTX+LDR groups, more significantly in the latter group than in the former group. Concentration of bone marrow cells and proliferation index in CTX + LDR group were higher than those in CTX group, although concentration of bone marrow cells in CTX and CTX+LDR groups were much lower than that in normal mice. Conclusion: Low dose radiation combined with cyclophosphamide causes more significant G 1 -phase arrest than cyclophosphamide alone and enhances anti-tumor effect markedly. At the same time LDR significantly protects hematopoietic function of bone marrow, which is of practical significance as an adjuvant chemotherapy
International Nuclear Information System (INIS)
Pandey, Anil Kumar; Sharma, Sanjay Kumar; Sharma, Punit; Gupta, Priyanka; Kumar, Rakesh
2013-01-01
It is important to ensure that as low as reasonably achievable (ALARA) concept during the radiopharmaceutical (RPH) dose administration in pediatric patients. Several methods have been suggested over the years for the calculation of individualized RPH dose, sometimes requiring complex calculations and large variability exists for administered dose in children. The aim of the present study was to develop a software application that can calculate and store RPH dose along with patient record. We reviewed the literature to select the dose formula and used Microsoft Access (a software package) to develop this application. We used the Microsoft Excel to verify the accurate execution of the dose formula. The manual and computer time using this program required for calculating the RPH dose were compared. The developed application calculates RPH dose for pediatric patients based on European Association of Nuclear Medicine dose card, weight based, body surface area based, Clark, Solomon Fried, Young and Webster's formula. It is password protected to prevent the accidental damage and stores the complete record of patients that can be exported to Excel sheet for further analysis. It reduces the burden of calculation and saves considerable time i.e., 2 min computer time as compared with 102 min (manual calculation with the calculator for all seven formulas for 25 patients). The software detailed above appears to be an easy and useful method for calculation of pediatric RPH dose in routine clinical practice. This software application will help in helping the user to routinely applied ALARA principle while pediatric dose administration. (author)
Can medical students calculate drug doses? | Harries | Southern ...
African Journals Online (AJOL)
... with calculations when the drug concentration was expressed either as a ratio or a percentage. Conclusion: Our findings support calls for the standardised labelling of drugs in solution and for dosage calculation training in the medical curriculum. Keywords: drug dosage calculations, clinical competence, medication errors
International Nuclear Information System (INIS)
Loureiro, E.C.M.; Khoury, H.; Lima, F.R.A.
1998-01-01
The increasing utilization of oral X-rays, specially in youngsters and children, prompts the assessment of equivalent doses in their organs and tissues. With this purpose, Monte Carlo code was adopted to simulate an X-ray source irradiating phantoms of the MIRD-5 type with different ages (10, 15 and 40 years old) to calculate the conversion coefficients which transform the exposure at skin to equivalent doses at several organs and tissues of interest. In order to check the computer program, simulations were performed for adult patients using the original code (ADAM,FOR developed by GSF Germany) and the adapted program (MCDRO,PAS). Good agreement between results obtained by both programs was observed. Applications to incisive, canine and molar teeth were simulated. The conversion factors were calculated for the following organs and tissues: thyroid, active bone marrow (head and whole body), bone (facial skeleton, cranium and whole body), skin (head and whole body) and crystalline. Based on the obtained results, it follows that the younger the patient and the langer the field area, the higher the doses in assessed organs and tissues
International Nuclear Information System (INIS)
Bahreyni Toossi, M. T.; Bayani, Sh.; Yarahmadi, M.; Aghamir, A.; Jomehzadeh, A.; Hagh Parast, M.; Tamjidi, A.
2009-01-01
Since 1996 the assessment of environmental gamma radiation dose in residential areas of Iranian towns and cities has been accomplished for 10 counties. As a practical method and based on the results of a pilot study, in order to attribute the final results to the whole residential area of a town five stations were selected for every town. The location of individual station was studied closely to comply with recommended conditions in the literature. Materials and Methods: RDS-110 was employed to measure gamma dose rate for one hour. Average annual dose rates plus conversion coefficients were employed to estimate gonad, bone marrow, equivalent and effective dose. Result: Minimum and maximum annual bone marrow and gonad dose equivalent attributed to environmental gamma are 0.24 mSvy -1 (for both tissues) and 1.44 and 1.46 mSvy -l , respectively. Conclusion: Average gonad and bone marrow doses for North Khorasan, Boshehr and Hormozgan provinces were less than the corresponding values for normal area.
International Nuclear Information System (INIS)
Takada, Takahiro; Furuya, Tomohisa; Ozawa, Shuichi; Ito, Kana; Kurokawa, Chie; Karasawa, Kumiko; Miura, Kohei
2008-01-01
AAA (analytical anisotropic algorithm) dose calculation, which shows a better performance for heterogeneity correction, was tested for lung stereotactic radiation therapy (SBRT) in comparison to conventional PBC (pencil beam convolution method) to evaluate its impact on tumor dose parameters. Eleven lung SBRT patients who were treated with photon 4 MV beams in our department between April 2003 and February 2007 were reviewed. Clinical target volume (CTV) was delineated including the spicula region on planning CT images. Planning target volume (PTV) was defined by adding the internal target volume (ITV) and set-up margin (SM) of 5 mm from CTV, and then an multileaf collimator (MLC) penumbra margin of another 5 mm was also added. Six-port non-coplanar beams were employed, and a total prescribed dose of 48 Gy was defined at the isocenter point with four fractions. The entire treatment for an individual patient was completed within 8 days. Under the same prescribed dose, calculated dose distribution, dose volume histogram (DVH), and tumor dose parameters were compared between two dose calculation methods. In addition, the fractionated prescription dose was repeatedly scaled until the monitor units (MUs) calculated by AAA reached a level of MUs nearly identical to those achieved by PBC. AAA resulted in significantly less D95 (irradiation dose that included 95% volume of PTV) and minimal dose in PTV compared to PBC. After rescaling of each MU for each beam in the AAA plan, there was no revision of the isocenter of the prescribed dose required. However, when the PTV volume was less than 20 cc, a 4% lower prescription resulted in nearly identical MUs between AAA and PBC. The prescribed dose in AAA should be the same as that in PBC, if the dose is administered at the isocenter point. However, planners should compare DVHs and dose distributions between AAA and PBC for a small lung tumor with a PTV volume less than approximately 20 cc. (author)
Applying the 'general principles of dose calculation' (ABG) in practice. Pt. 1
International Nuclear Information System (INIS)
Haubelt, R.
1985-01-01
Radiation doses are to be calculated for the main exposure pathways such as gamma submersion, beta submersion, gamma radiation at ground level, inhalation and ingestion of radionuclides. After the amendment of the German Radiation Protection Ordinance to include the latest ICRP Recommendations, the dose to be determined now is the effective dose equivalent, replacing the former whole-body dose equivalent. (DG) [de
International Nuclear Information System (INIS)
Ivanov, B.; Mileva, M.; Bulanova, M.; Pantev, T.
1982-01-01
Sexually mature wistor rats were irradiated on cesium gamma source ''IGUR-1'' with emissive power 3.25 mA/kg. The animals were divided in five groups of 10 rats each. They were irradiated respectively with 0.0129 C/kg, O, 0.0258 C/kg, 0.0516 C/kg, 0.1032 C/kg and control group. Five animals of each group received 300 meg/g weight Adeturone 15 minutes before exposure. The animals were sacrifices 20 hours after irradiation and preparations made from bone-marrow cells for chromosomal analysis. The number of structural chromosomal aberrations, aberrant cells and total number of aberrations in protected and in nonprotected cells were read under high-power microscope. The results were statistically processed by variation and regression analysis. It was found that Adeturone displays strong protective effect on the hereditary cell structures in all animals exposed to doses higher than 0.0129 C/kg, with the exception of chromatid fragments at a dose of 0.0258 C/kg. Mathematical models of the curves of the yields of chromatid and chromosomal fragments, aberrant cells and total number of aberrations in protected and nonprotected animals were described. (authors)
Schouten, IC; Raemaekers, JJM; Kluin-Nelemans, HC; vanKamp, H; Mellink, WAM; vantVeer, MB
1996-01-01
Purpose: To analyze whether, in addition to survival, and disease-free survival progression-free interval after transplantation would be longer than the last progression-free interval before transplantation, supporting the argument that high-dose therapy may change the biologic behavior of the
A Method for Correcting IMRT Optimizer Heterogeneity Dose Calculations
International Nuclear Information System (INIS)
Zacarias, Albert S.; Brown, Mellonie F.; Mills, Michael D.
2010-01-01
Radiation therapy treatment planning for volumes close to the patient's surface, in lung tissue and in the head and neck region, can be challenging for the planning system optimizer because of the complexity of the treatment and protected volumes, as well as striking heterogeneity corrections. Because it is often the goal of the planner to produce an isodose plan with uniform dose throughout the planning target volume (PTV), there is a need for improved planning optimization procedures for PTVs located in these anatomical regions. To illustrate such an improved procedure, we present a treatment planning case of a patient with a lung lesion located in the posterior right lung. The intensity-modulated radiation therapy (IMRT) plan generated using standard optimization procedures produced substantial dose nonuniformity across the tumor caused by the effect of lung tissue surrounding the tumor. We demonstrate a novel iterative method of dose correction performed on the initial IMRT plan to produce a more uniform dose distribution within the PTV. This optimization method corrected for the dose missing on the periphery of the PTV and reduced the maximum dose on the PTV to 106% from 120% on the representative IMRT plan.
The interpretation of animal data in the calculation of doses from new radiolabeled compounds
International Nuclear Information System (INIS)
Naylor, G.P.L.; Ellender, M.; Harrison, J.D.
1992-01-01
At NRPB, dose calculations are performed for pharmaceutical companies wishing to obtain approval for human volunteer experiments. Animal data from one or more species are used to estimate the radiation doses to humans that would result from the administration of novel radiolabeled compounds. The calculations themselves are straightforward, but the animal data can be interpreted in different ways, leading to variations in the calculated dose. Doses to the gut compartments usually dominate the committed effective dose equivalent, but retention in other tissues may be important for some compounds. Long-term retention components in tissues can affect doses considerably, and the binding of many radiopharmaceuticals to melanin means that doses to the eye are particularly important. The effect of these considerations on calculating doses are considered, as well as the effect of changes in risk estimates and tissue weighting factors
Analysis of offsite dose calculation methodology for a nuclear power reactor
International Nuclear Information System (INIS)
Moser, D.M.
1995-01-01
This technical study reviews the methodology for calculating offsite dose estimates as described in the offsite dose calculation manual (ODCM) for Pennsylvania Power and Light - Susquehanna Steam Electric Station (SSES). An evaluation of the SSES ODCM dose assessment methodology indicates that it conforms with methodology accepted by the US Nuclear Regulatory Commission (NRC). Using 1993 SSES effluent data, dose estimates are calculated according to SSES ODCM methodology and compared to the dose estimates calculated according to SSES ODCM and the computer model used to produce the reported 1993 dose estimates. The 1993 SSES dose estimates are based on the axioms of Publication 2 of the International Commission of Radiological Protection (ICRP). SSES Dose estimates based on the axioms of ICRP Publication 26 and 30 reveal the total body estimates to be the most affected
International Nuclear Information System (INIS)
Cowley, W.L.
1996-01-01
The analysis described in this report develops the Unit Liter Doses for use in the TWRS FSAR. The Unit Liter Doses provide a practical way to calculate conservative radiological consequences for a variety of potential accidents for the tank farms
Energy Technology Data Exchange (ETDEWEB)
Magome, Taiki [Department of Radiological Sciences, Faculty of Health Sciences, Komazawa University, Tokyo (Japan); Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota (United States); Department of Radiology, The University of Tokyo Hospital, Tokyo (Japan); Froelich, Jerry [Department of Radiology, University of Minnesota, Minneapolis, Minnesota (United States); Takahashi, Yutaka [Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota (United States); Department of Radiation Oncology, Osaka University, Osaka (Japan); Arentsen, Luke [Department of Therapeutic Radiology, University of Minnesota, Minneapolis, Minnesota (United States); Holtan, Shernan; Verneris, Michael R. [Blood and Marrow Transplant Program, University of Minnesota, Minneapolis, Minnesota (United States); Brown, Keenan [Mindways Software Inc, Austin, Texas (United States); Haga, Akihiro; Nakagawa, Keiichi [Department of Radiology, The University of Tokyo Hospital, Tokyo (Japan); Holter Chakrabarty, Jennifer L. [College of Medicine, Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Giebel, Sebastian [Department of Bone Marrow Transplantation, Comprehensive Cancer Center M. Curie-Sklodowska Memorial Institute, Gliwice (Poland); Wong, Jeffrey [Department of Radiation Oncology, Beckman Research Institute, City of Hope, Duarte, California (United States); Dusenbery, Kathryn [Department of Therapeutic Radiology, University of Minnesota, Minneapolis, Minnesota (United States); Storme, Guy [Department of Radiotherapy, Universitair Ziekenhuis Brussel, Brussels (Belgium); Hui, Susanta K., E-mail: shui@coh.org [Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota (United States); Department of Therapeutic Radiology, University of Minnesota, Minneapolis, Minnesota (United States); Department of Radiation Oncology, Beckman Research Institute, City of Hope, Duarte, California (United States)
2016-11-01
Purpose: To develop an imaging method to characterize and map marrow composition in the entire skeletal system, and to simulate differential targeted marrow irradiation based on marrow composition. Methods and Materials: Whole-body dual energy computed tomography (DECT) images of cadavers and leukemia patients were acquired, segmented to separate bone marrow components, namely, bone, red marrow (RM), and yellow marrow (YM). DECT-derived marrow fat fraction was validated using histology of lumbar vertebrae obtained from cadavers. The fractions of RM (RMF = RM/total marrow) and YMF were calculated in each skeletal region to assess the correlation of marrow composition with sites and ages. Treatment planning was simulated to target irradiation differentially at a higher dose (18 Gy) to either RM or YM and a lower dose (12 Gy) to the rest of the skeleton. Results: A significant correlation between fat fractions obtained from DECT and cadaver histology samples was observed (r=0.861, P<.0001, Pearson). The RMF decreased in the head, neck, and chest was significantly inversely correlated with age but did not show any significant age-related changes in the abdomen and pelvis regions. Conformity of radiation to targets (RM, YM) was significantly dependent on skeletal sites. The radiation exposure was significantly reduced (P<.05, t test) to organs at risk (OARs) in RM and YM irradiation compared with standard total marrow irradiation (TMI). Conclusions: Whole-body DECT offers a new imaging technique to visualize and measure skeletal-wide marrow composition. The DECT-based treatment planning offers volumetric and site-specific precise radiation dosimetry of RM and YM, which varies with aging. Our proposed method could be used as a functional compartment of TMI for further targeted radiation to specific bone marrow environment, dose escalation, reduction of doses to OARs, or a combination of these factors.
International Nuclear Information System (INIS)
Komemushi, A.; Tanigawa, N.; Kariya, Sh.; Yagi, R.; Nakatani, M.; Suzuki, S.; Sano, A.; Ikeda, K.; Utsunomiya, K.; Harima, Y.; Sawada, S.
2012-01-01
Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution
User Guide for GoldSim Model to Calculate PA/CA Doses and Limits
International Nuclear Information System (INIS)
Smith, F.
2016-01-01
A model to calculate doses for solid waste disposal at the Savannah River Site (SRS) and corresponding disposal limits has been developed using the GoldSim commercial software. The model implements the dose calculations documented in SRNL-STI-2015-00056, Rev. 0 ''Dose Calculation Methodology and Data for Solid Waste Performance Assessment (PA) and Composite Analysis (CA) at the Savannah River Site''.
User Guide for GoldSim Model to Calculate PA/CA Doses and Limits
Energy Technology Data Exchange (ETDEWEB)
Smith, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
2016-10-31
A model to calculate doses for solid waste disposal at the Savannah River Site (SRS) and corresponding disposal limits has been developed using the GoldSim commercial software. The model implements the dose calculations documented in SRNL-STI-2015-00056, Rev. 0 “Dose Calculation Methodology and Data for Solid Waste Performance Assessment (PA) and Composite Analysis (CA) at the Savannah River Site”.
International Nuclear Information System (INIS)
Hendry, J.H.; Wang, S.B.; Testa, N.G.
1984-01-01
The Do value fibroblastoid colony-forming units in mouse bone-marrow increased from 1.7 Gy using γ-rays at 4.2 Gy/minute, to 2.6 Gy at 4.5 cGy/minute. In contrast, the sensitivity of bone-marrow stem cells was very little changed (Do approximately 0.9 Gy). At 7.5 Gy acute single dose, the dose sparing achieved for CFU-F using 4.5 cGy/minute was a factor of 1.4, inbetween the values reported for lung of 1.8 and for haemopoiesis of 1.2. Although the role of CFU-F in the haemopoietic environment has not been established, the content of CFU-F can predict the ability of irradiated marrow to sustain haemopoiesis in the long term. Hence the data imply that the haemopoiesis environment, as well as the dose-limiting lung, benefits from the use of low dose-rates for haemopoietic ablations in the treatment of leukaemia. No significant further sparing of CFU-F was achieved using a lower dose-rate of 1.4 cGy per minute
Study of dose calculation and beam parameters optimization with genetic algorithm in IMRT
International Nuclear Information System (INIS)
Chen Chaomin; Tang Mutao; Zhou Linghong; Lv Qingwen; Wang Zhuoyu; Chen Guangjie
2006-01-01
Objective: To study the construction of dose calculation model and the method of automatic beam parameters selection in IMRT. Methods: The three-dimension convolution dose calculation model of photon was constructed with the methods of Fast Fourier Transform. The objective function based on dose constrain was used to evaluate the fitness of individuals. The beam weights were optimized with genetic algorithm. Results: After 100 iterative analyses, the treatment planning system produced highly conformal and homogeneous dose distributions. Conclusion: the throe-dimension convolution dose calculation model of photon gave more accurate results than the conventional models; genetic algorithm is valid and efficient in IMRT beam parameters optimization. (authors)
Calculation of dose point kernels for five radionuclides used in radio-immunotherapy
International Nuclear Information System (INIS)
Okigaki, S.; Ito, A.; Uchida, I.; Tomaru, T.
1994-01-01
With the recent interest in radioimmunotherapy, attention has been given to calculation of dose distribution from beta rays and monoenergetic electrons in tissue. Dose distribution around a point source of a beta ray emitting radioisotope is referred to as a beta dose point kernel. Beta dose point kernels for five radionuclides such as 131 I, 186 Re, 32 P, 188 Re, and 90 Y appropriate for radioimmunotherapy are calculated by Monte Carlo method using the EGS4 code system. Present results were compared with the published data of experiments and other calculations. Accuracy and precisions of beta dose point kernels are discussed. (author)
International Nuclear Information System (INIS)
Fadel, Ana M.; Chebel, G.M.; Valdivieso, C.M.; Degrossi, Osvaldo J.; Cabrejas, R.; Cabrejas, M.L.
2006-01-01
The optimum dose for the differentiated thyroid cancer treatment is a motive of controversy. There exist two ways of deciding the dose to administer: the empirical method (fixed doses) and dosimetric calculation method. The use of fixed doses has demonstrated safety and effectiveness. Nevertheless there are cases in which the use of several small doses not resolves the metastases illness of the patients. Using the Benua-Leeper method for dosimetric calculation we have evaluated the maximum dose treatment that could be administered to 20 patients who showed persistent disease after several treatments with 131 I. (author) [es
Monte-Carlo Method Python Library for dose distribution Calculation in Brachytherapy
Energy Technology Data Exchange (ETDEWEB)
Randriantsizafy, R D; Ramanandraibe, M J [Madagascar Institut National des Sciences et Techniques Nucleaires, Antananarivo (Madagascar); Raboanary, R [Institut of astro and High-Energy Physics Madagascar, University of Antananarivo, Antananarivo (Madagascar)
2007-07-01
The Cs-137 Brachytherapy treatment is performed in Madagascar since 2005. Time treatment calculation for prescribed dose is made manually. Monte-Carlo Method Python library written at Madagascar INSTN is experimentally used to calculate the dose distribution on the tumour and around it. The first validation of the code was done by comparing the library curves with the Nucletron company curves. To reduce the duration of the calculation, a Grid of PC's is set up with listner patch run on each PC. The library will be used to modelize the dose distribution in the CT scan patient picture for individual and better accuracy time calculation for a prescribed dose.
Monte-Carlo Method Python Library for dose distribution Calculation in Brachytherapy
International Nuclear Information System (INIS)
Randriantsizafy, R.D.; Ramanandraibe, M.J.; Raboanary, R.
2007-01-01
The Cs-137 Brachytherapy treatment is performed in Madagascar since 2005. Time treatment calculation for prescribed dose is made manually. Monte-Carlo Method Python library written at Madagascar INSTN is experimentally used to calculate the dose distribution on the tumour and around it. The first validation of the code was done by comparing the library curves with the Nucletron company curves. To reduce the duration of the calculation, a Grid of PC's is set up with listner patch run on each PC. The library will be used to modelize the dose distribution in the CT scan patient picture for individual and better accuracy time calculation for a prescribed dose.
Calculation of dose distribution on Rhizophora spp soy protein ...
African Journals Online (AJOL)
Some of the commercial solid phantoms were unable to provide a good simulation to water at low and high energy ranges. A potential phantom from Malaysian mangrove wood family, Rhizophoraspp was fabricated with addition of Soy Protein. An Electron Gamma Sho (EGSnrc) code was used to evaluate the dose ...
Experimental validation of Monte Carlo calculations for organ dose
International Nuclear Information System (INIS)
Yalcintas, M.G.; Eckerman, K.F.; Warner, G.G.
1980-01-01
The problem of validating estimates of absorbed dose due to photon energy deposition is examined. The computational approaches used for the estimation of the photon energy deposition is examined. The limited data for validation of these approaches is discussed and suggestions made as to how better validation information might be obtained
Paradigm shift in LUNG SBRT dose calculation associated with Heterogeneity correction
International Nuclear Information System (INIS)
Zucca Aparicio, D.; Perez Moreno, J. M.; Fernandez Leton, P.; Garcia Ruiz-Zorrilla, J.; Pinto Monedero, M.; Marti Asensjo, J.; Alonso Iracheta, L.
2015-01-01
Treatment of lung injury SBRT requires great dosimetric accuracy, the increasing clinical importance of dose calculation heterogeneities introducing algorithms that adequately model the transport of particles narrow beams in media of low density, as with Monte Carlo calculation. (Author)
Probabilistic calculation of dose commitment from uranium mill tailings
International Nuclear Information System (INIS)
1983-10-01
The report discusses in a general way considerations of uncertainty in relation to probabilistic modelling. An example of a probabilistic calculation applied to the behaviour of uranium mill tailings is given
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.
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.
Kinetics and dose calculations of amikacin in the newborn
DEFF Research Database (Denmark)
Sardemann, H; Colding, H; Hendel, J
1976-01-01
compartment model. The absorption was evaluated in 8 of the infants after intramuscular injection of 7.5 mg amikacin per kilogram of body weight. The absorption rate, estimated by the tmax, was significantly faster than reported in adults. The total body clearance and apparent volume of distribution were...... studied in 22 infants after the same dose of amikacin intramuscularly. The body clearance expressed in relation to body surface or body weight was significantly less than in adults and correlated with the postnatal age. No correlation could be demonstrated between clearance and gestational age or birth...... weight. The volume of distribution per kilogram was significantly greater than in adults. On the basis of the derived kinetic parameters, a dose schedule is presented. In 5 children there was a reasonable agreement between the measured and predicted serum levels....
Secondary standard dosimetry system with automatic dose/rate calculation
International Nuclear Information System (INIS)
Duftschmid, K.E.; Bernhart, J.; Stehno, G.; Klosch, W.
1980-01-01
A versatile and automated secondary standard instrument has been designed for quick and accurate dose/rate measurement in a wide range of radiation intensity and quality (between 1 μR and 100 kR; 0.2 nC/kg - 20C/kg) for protection and therapy level dosimetry. The system is based on a series of secondary standard ionization chambers connected to a precision digital current integrator with microprocessor circuitry for data evaluation and control. Input of measurement parameters and calibration factors stored in an exchangeable memory chip provide computation of dose/rate values in the desired units. The ionization chambers provide excellent long-term stability and energy response and can be used with internal check sources to test validity of calibration. The system is a useful tool particularly for daily measurements in a secondary standard dosimetry laboratory or radiation therapy center. (H.K.)
Energy Technology Data Exchange (ETDEWEB)
Vianello, Elizabeth A.; Almeida, Carlos E. de [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil); Biaggio, Maria F. de [Universidade do Estado, Rio de Janeiro, RJ (Brazil)
1998-09-01
This paper describes a manual method for dose calculation in brachytherapy of gynecological tumors, which allows the calculation of the doses at any plane or point of clinical interest. This method uses basic principles of vectorial algebra and the simulating orthogonal films taken from the patient with the applicators and dummy sources in place. The results obtained with method were compared with the values calculated with the values calculated with the treatment planning system model Theraplan and the agreement was better than 5% in most cases. The critical points associated with the final accuracy of the proposed method is related to the quality of the image and the appropriate selection of the magnification factors. This method is strongly recommended to the radiation oncology centers where are no treatment planning systems available and the dose calculations are manually done. (author) 10 refs., 5 figs.
Lu, Yifan; Tang, Guanghui; Lin, Hui; Lin, Xiaojie; Jiang, Lu; Yang, Guo-Yuan; Wang, Yongting
2017-06-01
Very limited experimental data is available regarding the safe dosages related to synchrotron radiation (SR) procedures. We used young rats and macaques to address bone marrow and skin tolerance to various doses of synchrotron radiation. Rats were subjected to 0, 0.5, 2.5, 5, 25 or 100 Gy local SR X-ray irradiation at left hind limb. Rat blood samples were analyzed at 2-90 days after irradiation. The SR X-ray irradiated skin and tibia were sectioned for morphological examination. For non-human primate study, three male macaques were subjected to 0.5 or 2.5 Gy SR X-ray on crus. Skin responses of macaques were observed. All rats that received SR X-ray irradiation doses greater than 2.5 Gy experienced hair loss and bone-growth inhibition, which were accompanied by decreased number of follicles, thickened epidermal layer, and decreased density of bone marrow cells (p X-ray but showed significant hair loss when the dose was raised above 2.5 Gy. The safety threshold doses of SR X-ray for rat skin, bone marrow and macaque skin are between 0.5 and 2.5 Gy. Our study provided essential information regarding the biosafety of SR X-ray irradiation.
Recommended environmental dose calculation methods and Hanford-specific parameters
International Nuclear Information System (INIS)
Schreckhise, R.G.; Rhoads, K.; Napier, B.A.; Ramsdell, J.V.; Davis, J.S.
1993-03-01
This document was developed to support the Hanford Environmental Dose overview Panel (HEDOP). The Panel is responsible for reviewing all assessments of potential doses received by humans and other biota resulting from the actual or possible environmental releases of radioactive and other hazardous materials from facilities and/or operations belonging to the US Department of Energy on the Hanford Site in south-central Washington. This document serves as a guide to be used for developing estimates of potential radiation doses, or other measures of risk or health impacts, to people and other biota in the environs on and around the Hanford Site. It provides information to develop technically sound estimates of exposure (i.e., potential or actual) to humans or other biotic receptors that could result from the environmental transport of potentially harmful materials that have been, or could be, released from Hanford operations or facilities. Parameter values and information that are specific to the Hanford environs as well as other supporting material are included in this document
Recommended environmental dose calculation methods and Hanford-specific parameters
Energy Technology Data Exchange (ETDEWEB)
Schreckhise, R.G.; Rhoads, K.; Napier, B.A.; Ramsdell, J.V. (Pacific Northwest Lab., Richland, WA (United States)); Davis, J.S. (Westinghouse Hanford Co., Richland, WA (United States))
1993-03-01
This document was developed to support the Hanford Environmental Dose overview Panel (HEDOP). The Panel is responsible for reviewing all assessments of potential doses received by humans and other biota resulting from the actual or possible environmental releases of radioactive and other hazardous materials from facilities and/or operations belonging to the US Department of Energy on the Hanford Site in south-central Washington. This document serves as a guide to be used for developing estimates of potential radiation doses, or other measures of risk or health impacts, to people and other biota in the environs on and around the Hanford Site. It provides information to develop technically sound estimates of exposure (i.e., potential or actual) to humans or other biotic receptors that could result from the environmental transport of potentially harmful materials that have been, or could be, released from Hanford operations or facilities. Parameter values and information that are specific to the Hanford environs as well as other supporting material are included in this document.
Energy Technology Data Exchange (ETDEWEB)
Saitou, Mikio; Sirata, Katsutoshi; Yanai, Takanori; Tanaka, Satoshi; Onodera, Junichi; Otsu, Hiroshi; Sato, Fumiaki [Institute for Environmental Sciences, Department of Radiobiology, Rokkasho, Aomori (Japan)
1999-07-01
To evaluate effects of prolonged irradiation by low dose-rate ionizing radiation on the production of growth factors of cells, the dose dependency of the expression of cytokines, interleukin-6 (IL-6) and granulocyte-macrophage colony stimulating factor (GM-CSF), of mice is being measured at accumulated doses between 1 and 8 Gy, with the dose interval of 1 Gy. In the present work, specific-pathogen-free (SPF) C3H-HeN female mice were irradiated by {sup 137}Cs {gamma}-rays with the doses of 5-8 Gy at the dose rate of 20 mGy (22 h-day){sup -1}, and the expression of IL-6 and GM-CSF in bone marrow and spleen cells from the mice were measured semiquantitatively by the reverse transcriptase-polymerase chain reaction (RT-PCR) method. (author)
CARI NAIRAS: Calculating Flight Doses from NAIRAS Data using CARI
2014-12-01
S44 (1996). 5. O’Brien, K; Smart, DF; Shea, MA; et al. World-wide radiation dosage calculations for air crew members. Advan Space Res, 2003, 31(4...STEPMIN(I), STEPFEET(I) ENDDO WRITE(40,*) ‘RDBIGFLT RETURNS CRUISE TIME (MIN): ‘,CRUISEMIN WRITE(40,*) ‘RDBIGFLT RETURNS DESCENT TIME (MIN...USE ONE STEP PER MINUTE, CENTERED ON 1/2 STEP IF (DIAGNOSE.EQ.’YES’) WRITE(40,*) ‘CALCULATING DESCENT ’ CALL FT2KM(DALT,DEPTH(ALLSTEPS)) DT(J
Independent Monte-Carlo dose calculation for MLC based CyberKnife radiotherapy
Mackeprang, P.-H.; Vuong, D.; Volken, W.; Henzen, D.; Schmidhalter, D.; Malthaner, M.; Mueller, S.; Frei, D.; Stampanoni, M. F. M.; Dal Pra, A.; Aebersold, D. M.; Fix, M. K.; Manser, P.
2018-01-01
This work aims to develop, implement and validate a Monte Carlo (MC)-based independent dose calculation (IDC) framework to perform patient-specific quality assurance (QA) for multi-leaf collimator (MLC)-based CyberKnife® (Accuray Inc., Sunnyvale, CA) treatment plans. The IDC framework uses an XML-format treatment plan as exported from the treatment planning system (TPS) and DICOM format patient CT data, an MC beam model using phase spaces, CyberKnife MLC beam modifier transport using the EGS++ class library, a beam sampling and coordinate transformation engine and dose scoring using DOSXYZnrc. The framework is validated against dose profiles and depth dose curves of single beams with varying field sizes in a water tank in units of cGy/Monitor Unit and against a 2D dose distribution of a full prostate treatment plan measured with Gafchromic EBT3 (Ashland Advanced Materials, Bridgewater, NJ) film in a homogeneous water-equivalent slab phantom. The film measurement is compared to IDC results by gamma analysis using 2% (global)/2 mm criteria. Further, the dose distribution of the clinical treatment plan in the patient CT is compared to TPS calculation by gamma analysis using the same criteria. Dose profiles from IDC calculation in a homogeneous water phantom agree within 2.3% of the global max dose or 1 mm distance to agreement to measurements for all except the smallest field size. Comparing the film measurement to calculated dose, 99.9% of all voxels pass gamma analysis, comparing dose calculated by the IDC framework to TPS calculated dose for the clinical prostate plan shows 99.0% passing rate. IDC calculated dose is found to be up to 5.6% lower than dose calculated by the TPS in this case near metal fiducial markers. An MC-based modular IDC framework was successfully developed, implemented and validated against measurements and is now available to perform patient-specific QA by IDC.
Energy Technology Data Exchange (ETDEWEB)
Napier, B.A.; Kennedy, W.E. Jr.; Soldat, J.K.
1980-03-01
A computer program, PABLM, was written to facilitate the calculation of internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. This report contains details of mathematical models used and calculational procedures required to run the computer program. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides in the environment after the releases have ended. Radioactive decay is considered during the release of radionuclides, after they are deposited on the plants or ground, and during holdup of food after harvest. The radiation dose models consider several exposure pathways. Doses may be calculated for either a maximum-exposed individual or for a population group. The doses calculated are accumulated doses from continuous chronic exposure. A first-year committed dose is calculated as well as an integrated dose for a selected number of years. The equations for calculating internal radiation doses are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and MPC's of each radionuclide. The radiation doses from external exposure to contaminated water and soil are calculated using the basic assumption that the contaminated medium is large enough to be considered an infinite volume or plane relative to the range of the emitted radiations. The equations for calculations of the radiation dose from external exposure to shoreline sediments include a correction for the finite width of the contaminated beach.
Calculation of Dose Gamma Ray Build up Factor in Some ...
African Journals Online (AJOL)
The gamma ray buildup factor was calculated by analyzing the narrow- beam and broad-beam geometry equations using Taylor's formula for isotropic sources and homogeneous materials. The buildup factor was programmed using MATLAB software to operate with any radiation energy (E), atomic number (Z) and the ...
Evaluation of a new commercial Monte Carlo dose calculation algorithm for electron beams.
Vandervoort, Eric J; Tchistiakova, Ekaterina; La Russa, Daniel J; Cygler, Joanna E
2014-02-01
In this report the authors present the validation of a Monte Carlo dose calculation algorithm (XiO EMC from Elekta Software) for electron beams. Calculated and measured dose distributions were compared for homogeneous water phantoms and for a 3D heterogeneous phantom meant to approximate the geometry of a trachea and spine. Comparisons of measurements and calculated data were performed using 2D and 3D gamma index dose comparison metrics. Measured outputs agree with calculated values within estimated uncertainties for standard and extended SSDs for open applicators, and for cutouts, with the exception of the 17 MeV electron beam at extended SSD for cutout sizes smaller than 5 × 5 cm(2). Good agreement was obtained between calculated and experimental depth dose curves and dose profiles (minimum number of measurements that pass a 2%/2 mm agreement 2D gamma index criteria for any applicator or energy was 97%). Dose calculations in a heterogeneous phantom agree with radiochromic film measurements (>98% of pixels pass a 3 dimensional 3%/2 mm γ-criteria) provided that the steep dose gradient in the depth direction is considered. Clinically acceptable agreement (at the 2%/2 mm level) between the measurements and calculated data for measurements in water are obtained for this dose calculation algorithm. Radiochromic film is a useful tool to evaluate the accuracy of electron MC treatment planning systems in heterogeneous media.
Comparison of measured and calculated doses for narrow MLC defined fields
International Nuclear Information System (INIS)
Lydon, J.; Rozenfeld, A.; Lerch, M.
2002-01-01
Full text: The introduction of Intensity Modulated Radiotherapy (IMRT) has led to the use of narrow fields in the delivery of radiation doses to patients. Such fields are not well characterized by calculation methods commonly used in radiotherapy treatment planning systems. The accuracy of the dose calculation algorithm must therefore be investigated prior to clinical use. This study looked at symmetrical and asymmetrical 0.1 to 3cm wide fields delivered with a Varian CL2100C 6MV photon beam. Measured doses were compared to doses calculated using Pinnacle, the ADAC radiotherapy treatment planning system. Two high resolution methods of measuring dose were used. A MOSFET detector in a water phantom and radiographic film in a solid water phantom with spatial resolutions of 10 and 89μm respectively. Dose calculations were performed using the collapsed cone convolution algorithm in Pinnacle with a 0.1cm dose calculation grid in the MLC direction. The effect of Pinnacle not taking into account the rounded leaf ends was simulated by offsetting the leaves by 0.1cm in the dose calculation. Agreement between measurement and calculation is good for fields of 1cm and wider. However, fields of less than 1cm width can show a significant difference between measurement and calculation
Construction of voxel head phantom and application to BNCT dose calculation
Energy Technology Data Exchange (ETDEWEB)
Lee, Choon Sik; Lee, Choon Ik; Lee, Jai Ki [Hanyang Univ., Seoul (Korea, Republic of)
2001-06-15
Voxel head phantom for overcoming the limitation of mathematical phantom in depicting anatomical details was constructed and example dose calculation for BNCT was performed. The repeated structure algorithm of the general purpose Monte Carlo code, MCNP4B was applied for voxel Monte Carlo calculation. Simple binary voxel phantom and combinatorial geometry phantom composed of two materials were constructed for validating the voxel Monte Carlo calculation system. The tomographic images of VHP man provided by NLM(National Library of Medicine) were segmented and indexed to construct voxel head phantom. Comparison od doses for broad parallel gamma and neutron beams in AP and PA directions showed decrease of brain dose due to the attenuation of neutron in eye balls in case of voxel head phantom. The spherical tumor volume with diameter, 5cm was defined in the center of brain for BNCT dose calculation in which accurate 3 dimensional dose calculation is essential. As a result of BNCT dose calculation for downward neutron beam of 10keV and 40keV, the tumor dose is about doubled when boron concentration ratio between the tumor to the normal tissue is 30{mu}g/g to 3 {mu}g/g. This study established the voxel Monte Carlo calculation system and suggested the feasibility of precise dose calculation in therapeutic radiology.
The calculation of electron depth-dose distributions in multilayer medium
International Nuclear Information System (INIS)
Wang Chuanshan; Xu Mengjie; Li Zhiliang; Feng Yongxiang; Li Panlin
1989-01-01
Energy deposition in multilayer medium and the depth dose distribution in the layers are studied. Based on semi-empirical calculation of electron energy absorption in matter with EDMULT program of Tabata and Ito, further work has been carried out to extend the computation to multilayer composite material. New program developed in this paper makes IBM-PC compatible with complicated electron dose calculations
Dose calculation due to electrons interaction with DNA
Energy Technology Data Exchange (ETDEWEB)
Mark, S; Orion, I; Shani, G [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Nuclear Engineering; Laster, B [Brookhaven National Lab., Upton, NY (United States)
1996-12-01
Experiments done with gadolinium loaded V79 Chinese Hamster cells, irradiated with thermal neutrons, showed that cells lethality increased by a factor of 1.8 compared to the case where the Gd atoms were located outside the cell.(l) It was obvious that the dramatic increase in cell lethality is due to the emission of Auger electrons following the {sup 157}Gd(n,{gamma}){sup 158}Gd reaction. Electrons of various energies from about 40 keV (very few) to less than 1 keV, are emitted. In the present work, energy absorbed in DNA was calculated, due to interaction of electron of different energies: 30, 15, 10, 8, 5 and 2 keV. The Monte Carlo code EGS4(2) was used for the calculations. The DNA was modeled as a series of alternative layers of sugar (phosphate - C{sub 5}O{sub 5}H{sub 7}P p=1.39gr cm{sup -1}) and water. The sugar layer thickness was assumed 2.5nm and the water layer thickness 10nm. An isotropic electron source was assumed to be located in a water layer and the electrons interactions (absorption and scattering) were calculated in the forward hemisphere. The energy absorbed in a group of 8 layers, (4 sugar and 4 water) was calculated for each one of the electron energies. An interesting fact found in those calculations; when the source electrons energy is 10 keV or more, most of the electrons are absorbed in the DNA-water system, are at energy about 2keV. There is no good explanation for this phenomenon except for assuming that when the electron`s energy reaches a low point of about 2keV, it cannot escape absorption in the medium. 10% of the 10 keV electrons deposit their entire energy in the 8 layers range (authors).
Calculation of absorbed dose in water by chemical Fricke dosimetry
International Nuclear Information System (INIS)
Rodrigues, Adenilson Paiva; Meireles, Ramiro Conceicao
2016-01-01
This work is the result of a laboratory activity performed in Radiological Sciences Laboratory (CRL), linked to the State University of Rio de Janeiro (UERJ). This practice aimed to determine the absorbed dose to water, through the primary calibration method called dosimetry Fricke, which consists of ferrous ions (Fe + 2) to ferric (Fe + 3), generated by water radiolysis products which is the structural change of water molecule caused by ionizing radiation. A spectrophotometer was used to extract data for analysis at a wavelength (λ) 304 and 224 nm with function of measuring the absorbance using bottles with irradiated and nonirradiated Fricke solution. (author)
Calculation of age-dependent effective doses for external exposure using the MCNP code
International Nuclear Information System (INIS)
Hung, Tran Van
2013-01-01
Age-dependent effective dose for external exposure to photons uniformly distributed in air were calculated. Firstly, organ doses were calculated with a series of age-specific MIRD-5 type phantoms using the Monte Carlo code MCNP. The calculations were performed for mono-energetic photon sources with source energies from 10 keV to 5 MeV and for phantoms of newborn, 1, 5, 10, and 15 years-old and adult. Then, the effective doses to the different age-phantoms from the mono-energetic photon sources were estimated based on the obtained organ doses. From the calculated results, it is shown that the effective doses depend on the body size; the effective doses in younger phantoms are higher than those in the older phantoms, especially below 100 keV. (orig.)
Calculation of age-dependent effective doses for external exposure using the MCNP code
Energy Technology Data Exchange (ETDEWEB)
Hung, Tran Van [Research and Development Center for Radiation Technology, ThuDuc, HoChiMinh City (VT)
2013-07-15
Age-dependent effective dose for external exposure to photons uniformly distributed in air were calculated. Firstly, organ doses were calculated with a series of age-specific MIRD-5 type phantoms using the Monte Carlo code MCNP. The calculations were performed for mono-energetic photon sources with source energies from 10 keV to 5 MeV and for phantoms of newborn, 1, 5, 10, and 15 years-old and adult. Then, the effective doses to the different age-phantoms from the mono-energetic photon sources were estimated based on the obtained organ doses. From the calculated results, it is shown that the effective doses depend on the body size; the effective doses in younger phantoms are higher than those in the older phantoms, especially below 100 keV. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Maillie, H D; Baxter, R C; Lisman, H [Rochester Univ., N.Y. (USA). School of Medicine and Dentistry
1977-11-01
The /sup 59/Fe uptake system was used to estimate the dose distribution throughout sham-operated and splenectomized rats exposed to whole-body 1000 kVp x irradiation. The marrow in the splenectomized animals was found to be slightly more radiosensitive. However, the difference between the two groups of rats was not significant. The dose distributions throughout the marrow of both groups were the same. It was concluded that splenectomy had no effect on the usefulness of this method. The method of measuring /sup 59/Fe uptake in this study used the uptake of radioiron at 6 hr post-injection and the deduction of the activity due to circulating iron. This resulted in a technique capable of measuring changes in iron uptake with midline-air-exposures of 25 R.
Energy Technology Data Exchange (ETDEWEB)
Mead, H [Christian Brothers University, Memphis, TN (United States); St. Jude Children’s Research Hospital, Memphis, TN (United States); Brady, S; Kaufman, R [St. Jude Children’s Research Hospital, Memphis, TN (United States)
2016-06-15
Purpose: To discover if a previously published methodology for estimating patient-specific organ dose in a pediatric population (5–55kg) is translatable to the adult sized patient population (> 55 kg). Methods: An adult male anthropomorphic phantom was scanned with metal oxide semiconductor field effect transistor (MOSFET) dosimeters placed at 23 organ locations in the chest and abdominopelvic regions to determine absolute organ dose. Organ-dose-to-SSDE correlation factors were developed by dividing individual phantom organ doses by SSDE of the phantom; where SSDE was calculated at the center of the scan volume of the chest and abdomen/pelvis separately. Organ dose correlation factors developed in phantom were multiplied by 28 chest and 22 abdominopelvic patient SSDE values to estimate organ dose. The median patient weight from the CT examinations was 68.9 kg (range 57–87 kg) and median age was 17 years (range 13–28 years). Calculated organ dose estimates were compared to published Monte Carlo simulated patient and phantom results. Results: Organ-dose-to-SSDE correlation was determined for a total of 23 organs in the chest and abdominopelvic regions. For organs fully covered by the scan volume, correlation in the chest (median 1.3; range 1.1–1.5) and abdominopelvic (median 0.9; range 0.7–1.0) was 1.0 ± 10%. For organs that extended beyond the scan volume (i.e. skin bone marrow and bone surface) correlation was determined to be a median of 0.3 (range 0.1–0.4). Calculated patient organ dose using patient SSDE agreed to better than 6% (chest) and 15% (abdominopelvic) to published values. Conclusion: This study demonstrated that our previous published methodology for calculating organ dose using patient-specific SSDE for the chest and abdominopelvic regions is translatable to adult sized patients for organs fully covered by the scan volume.
International Nuclear Information System (INIS)
Simmer, Gregor
2012-01-01
Due to secondary cosmic radiation (SCR), pilots and flight attendants receive elevated effective doses at flight altitudes. For this reason, since 2003 aircrew members are considered as occupationally exposed, in Germany. This work deals with the calculation of dose conversion coefficients (DCC) for protons, neutrons, electrons, positrons, photons and myons, which are crucial for estimation of effective dose from SCR. For the first time, calculations were performed combining Geant4 - a Monte Carlo code developed at CERN - with the voxel phantoms for the reference female and male published in 2008 by ICRP and ICRU. Furthermore, measurements of neutron fluence spectra - which contribute the major part to the effective dose of SCR - were carried out at the Environmental Research Station Schneefernerhaus (UFS) located at 2650 m above sea level nearby the Zugspitze mountain, Germany. These measured neutron spectra, and additionally available calculated spectra, were then folded with the DCC calculated in this work, and effective dose rates for different heights were calculated.
Sakamoto, Y
2002-01-01
In the prevention of nuclear disaster, there needs the information on the dose equivalent rate distribution inside and outside the site, and energy spectra. The three dimensional radiation transport calculation code is a useful tool for the site specific detailed analysis with the consideration of facility structures. It is important in the prediction of individual doses in the future countermeasure that the reliability of the evaluation methods of dose equivalent rate distribution and energy spectra by using of Monte Carlo radiation transport calculation code, and the factors which influence the dose equivalent rate distribution outside the site are confirmed. The reliability of radiation transport calculation code and the influence factors of dose equivalent rate distribution were examined through the analyses of critical accident at JCO's uranium processing plant occurred on September 30, 1999. The radiation transport calculations including the burn-up calculations were done by using of the structural info...
Effect of Embolization Material in the Calculation of Dose Deposition in Arteriovenous Malformations
International Nuclear Information System (INIS)
De la Cruz, O. O. Galvan; Moreno-Jimenez, S.; Larraga-Gutierrez, J. M.; Celis-Lopez, M. A.
2010-01-01
In this work it is studied the impact of the incorporation of high Z materials (embolization material) in the dose calculation for stereotactic radiosurgery treatment for arteriovenous malformations. A statistical analysis is done to establish the variables that may impact in the dose calculation. To perform the comparison pencil beam (PB) and Monte Carlo (MC) calculation algorithms were used. The comparison between both dose calculations shows that PB overestimates the dose deposited. The statistical analysis, for the quantity of patients of the study (20), shows that the variable that may impact in the dose calculation is the volume of the high Z material in the arteriovenous malformation. Further studies have to be done to establish the clinical impact with the radiosurgery result.
Oblique incidence of electron beams - comparisons between calculated and measured dose distributions
International Nuclear Information System (INIS)
Karcher, J.; Paulsen, F.; Christ, G.
2005-01-01
Clinical applications of high-energy electron beams, for example for the irradiation of internal mammary lymph nodes, can lead to oblique incidence of the beams. It is well known that oblique incidence of electron beams can alter the depth dose distribution as well as the specific dose per monitor unit. The dose per monitor unit is the absorbed dose in a point of interest of a beam, which is reached with a specific dose monitor value (DIN 6814-8[5]). Dose distribution and dose per monitor unit at oblique incidence were measured with a small-volume thimble chamber in a water phantom, and compared to both normal incidence and calculations of the Helax TMS 6.1 treatment planning system. At 4 MeV and 60 degrees, the maximum measured dose per monitor unit at oblique incidence was decreased up to 11%, whereas at 18MeV and 60 degrees this was increased up to 15% compared to normal incidence. Comparisons of measured and calculated dose distributions showed that the predicted dose at shallow depths is usually higher than the measured one, whereas it is smaller at depths beyond the depth of maximum dose. On the basis of the results of these comparisons, normalization depths and correction factors for the dose monitor value were suggested to correct the calculations of the dose per monitor unit. (orig.)
Probabilistic approach to external cloud dose calculations using onsite meteorological data
International Nuclear Information System (INIS)
Strenge, D.L.; Watson, E.C.; Bander, T.J.; Kennedy, W.E.
1976-01-01
A method is described for calculation of external total body and skin doses from accidental atmospheric releases of radionuclides based on hourly onsite meteorological data. The method involves calculation of dose values from a finite size cloud for each hourly observation for a given radionuclide inventory. These values are then used to determine the probability of occurrence of dose levels for specified release times ranging from one hour to 30 days
Calculation of the effective dose from natural radioactivity sources in soil using MCNP code
International Nuclear Information System (INIS)
Krstic, D.; Nikezic, D.
2008-01-01
Full text: Effective dose delivered by photon emitted from natural radioactivity in soil was calculated in this report. Calculations have been done for the most common natural radionuclides in soil as 238 U, 232 Th series and 40 K. A ORNL age-dependent phantom and the Monte Carlo transport code MCNP-4B were employed to calculate the energy deposited in all organs of phantom.The effective dose was calculated according to ICRP74 recommendations. Conversion coefficients of effective dose per air kerma were determined. Results obtained here were compared with other authors
Calculation of the effective dose from natural radioactivity in soil using MCNP code.
Krstic, D; Nikezic, D
2010-01-01
Effective dose delivered by photon emitted from natural radioactivity in soil was calculated in this work. Calculations have been done for the most common natural radionuclides in soil (238)U, (232)Th series and (40)K. A ORNL human phantoms and the Monte Carlo transport code MCNP-4B were employed to calculate the energy deposited in all organs. The effective dose was calculated according to ICRP 74 recommendations. Conversion factors of effective dose per air kerma were determined. Results obtained here were compared with other authors. Copyright 2009 Elsevier Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Larsson, Erik; Ljungberg, Michael; Martensson, Linda; Nilsson, Rune; Tennvall, Jan; Strand, Sven-Erik; Joensson, Bo-Anders [Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund (Sweden); Department of Oncology, Clinical Sciences, Lund University, Lund (Sweden); Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund (Sweden)
2012-07-15
Purpose: Biokinetic and dosimetry studies in laboratory animals often precede clinical radionuclide therapies in humans. A reliable evaluation of therapeutic efficacy is essential and should be based on accurate dosimetry data from a realistic dosimetry model. The aim of this study was to develop an anatomically realistic dosimetry model for Brown Norway rats to calculate S factors for use in evaluating correlations between absorbed dose and biological effects in a preclinical therapy study. Methods: A realistic rat phantom (Roby) was used, which has some flexibility that allows for a redefinition of organ sizes. The phantom was modified to represent the anatomic geometry of a Brown Norway rat, which was used for Monte Carlo calculations of S factors. Kinetic data for radiolabeled BR96 monoclonal antibodies were used to calculate the absorbed dose. Biological data were gathered from an activity escalation study with {sup 90}Y- and {sup 177}Lu-labeled BR96 monoclonal antibodies, in which blood cell counts and bodyweight were examined up to 2 months follow-up after injection. Reductions in white blood cell and platelet counts and declines in bodyweight were quantified by four methods and compared to the calculated absorbed dose to the bone marrow or the total body. Results: A red marrow absorbed dose-dependent effect on hematological parameters was observed, which could be evaluated by a decrease in blood cell counts. The absorbed dose to the bone marrow, corresponding to the maximal tolerable activity that could safely be administered, was determined to 8.3 Gy for {sup 177}Lu and 12.5 Gy for {sup 90}Y. Conclusions: There was a clear correlation between the hematological effects, quantified with some of the studied parameters, and the calculated red marrow absorbed doses. The decline in body weight was stronger correlated to the total body absorbed dose, rather than the red marrow absorbed dose. Finally, when considering a constant activity concentration, the phantom
International Nuclear Information System (INIS)
Carneiro, L.B.; Dourado, M.A.; Barbosa, R.C.
2017-01-01
To reassess the calculations of the effective dose equivalent to obtain data of dosimetry and the accomplishment of the analysis comparing the data of several techniques that record doses of radiation originating from the cosmogenic and terrestrial contributions that make up the so-called background radiation. the basic information to be obtained is the contribution of the difference between the terrestrial dose equivalents, even the lowest concentration of primordial radionuclides, and that of the dose equivalent, deduced from TLD readings. (author)
Energy Technology Data Exchange (ETDEWEB)
Carneiro, L.B.; Dourado, M.A.; Barbosa, R.C., E-mail: research.photonics@gmail.com [Centro Regional de Ciências Nucleares do Centro-Oeste (CRCN-CO/CNEN-GO), Abadia de Goiás, GO (Brazil)
2017-07-01
To reassess the calculations of the effective dose equivalent to obtain data of dosimetry and the accomplishment of the analysis comparing the data of several techniques that record doses of radiation originating from the cosmogenic and terrestrial contributions that make up the so-called background radiation. the basic information to be obtained is the contribution of the difference between the terrestrial dose equivalents, even the lowest concentration of primordial radionuclides, and that of the dose equivalent, deduced from TLD readings. (author)
International Nuclear Information System (INIS)
Bahreyni Toossi, M.T.; Bayani, S.H.; Abdolrahimi, A.; Yarahmadi, M.; Aghamir, A.; Jomehzadeh, A.; Hagh Parast, M.; Tamjidi, A.
2008-01-01
Natural radiation environment and it's biological impacts on human life has not received appreciable attention in Iran. Before 1996 only a few sporadic studies had been carried out, but no systematic study of normal back ground had been conducted. Since 1996 assessment of environmental gamma radiation dose in residential areas of Iranian towns and cities was defined as a long term goal in our center. Till now measurements of annual dose rates have been accomplished for 10 counties. As a practical method and based on the results of a pilot study, in order to attribute the final results to the whole residential area of a town five stations were selected for every town. The location of individual station was studied closely to comply with recommended conditions in the literature. RDS-110 was employed to measure gamma dose rate for one hour. Practically huge numbers of dose rate figures were recorded, they were substantially summarized to estimate average dose rate. Average annual dose rates plus conversion coefficients were employed to estimate gonad, bone marrow, equivalent and effective dose. In the vast studied area average out-door gamma dose rate is varying from 35 nSvh -1 to 205 nSvh -1 . Minimum and maximum annual bone marrow and gonad dose equivalent attributed to environmental gamma are 0.24 mSvy -1 (for both tissues) and 1.44 and 1.46 mSvy -1 respectively. Effective dose of inhabitants arising from out-door gamma is varying by 6 folds from 0.21 to 1.26 mSvy -1 . The largest and smallest population weighted dose are equal to 0.35 and 1.00 mSvy -1 . Average gonad and bone marrow doses for north Khorasan, Boshehr and Hormozgan are less than the corresponding values for normal area. On the other hand inhabitants of the studied area receive a dose higher than the world average, except those who live in Hormozgan and Boshehr. (author)
International Nuclear Information System (INIS)
Gelin, R.; Kjellbert, N.; Stenquist, C.
1978-09-01
Calculations of diffusion and radiation doses in connection with final storage of low-lavel and intermediate-level radioactive wastes. The results show that the doses obtained with realistic values of parameters used in the calculations are very low. However, substantially simplified assumption have been applied in the calculations. Thus more detailed models for the description of the diffusion process have to be developed. (E.R.)
Bevelacqua, J J
2011-07-01
Conservatism in the calculation of the effective dose following an airborne release from an accident involving a fuel reprocessing waste tank is examined. Within the regulatory constraints at the Hanford Site, deterministic effective dose calculations are conservative by at least an order of magnitude. Deterministic calculations should be used with caution in reaching decisions associated with required safety systems and mitigation philosophy related to the accidental release of airborne radioactive material to the environment.
Energy Technology Data Exchange (ETDEWEB)
Saitou, Mikio; Yamada, Yutaka; Shirata, Katsutoshi; Yanai, Takanori; Izumi, Jun; Tanaka, Satoshi; Onodera, Jun' ichi; Otsu, Hiroshi; Sato, Fumiaki [Institute for Environmental Sciences, Rokkasho, Aomori (Japan)
2000-07-01
To evaluate effects of prolonged irradiation by low dose-rate ionizing radiation on the production of growth factors of cells, the expression of cytokines, interleukin-6 (IL-6) and granulocyte-macrophage colony stimulating factor (GM-CSF), of mice is being measured at accumulated doses between 1 and 8 Gy, with the dose interval of 1 Gy. In the present work, ten specific-pathogen-free (SPF) C3H/HeN female mice per experimental group were irradiated with {sup 137}Cs {gamma}-rays with the doses of 1-4 Gy at the dose rate of 20 mGy/(22 h-day), and the expression of IL-6 and GM-CSF in bone marrow and spleen cells from the mice was measured semiquantitatively by the reverse transcriptase-polymerase chain reaction (RT-PCR) method. (author)
International Nuclear Information System (INIS)
Saitou, Mikio; Yamada, Yutaka; Shirata, Katsutoshi; Yanai, Takanori; Izumi, Jun; Tanaka, Satoshi; Onodera, Jun'ichi; Otsu, Hiroshi; Sato, Fumiaki
2000-01-01
To evaluate effects of prolonged irradiation by low dose-rate ionizing radiation on the production of growth factors of cells, the expression of cytokines, interleukin-6 (IL-6) and granulocyte-macrophage colony stimulating factor (GM-CSF), of mice is being measured at accumulated doses between 1 and 8 Gy, with the dose interval of 1 Gy. In the present work, ten specific-pathogen-free (SPF) C3H/HeN female mice per experimental group were irradiated with 137 Cs γ-rays with the doses of 1-4 Gy at the dose rate of 20 mGy/(22 h-day), and the expression of IL-6 and GM-CSF in bone marrow and spleen cells from the mice was measured semiquantitatively by the reverse transcriptase-polymerase chain reaction (RT-PCR) method. (author)
International Nuclear Information System (INIS)
Caracappa, Peter F.; Xu, X. George; Gu, Jianwei
2011-01-01
The comparatively high dose and increasing frequency of computed tomography (CT) examinations have spurred the development of techniques for reducing radiation dose to imaging patients. Among these is the application of tube current modulation (TCM), which can be applied either longitudinally along the body or rotationally along the body, or both. Existing computational models for calculating dose from CT examinations do not include TCM techniques. Dose calculations using Monte Carlo methods have been previously prepared for constant-current rotational exposures at various positions along the body and for the principle exposure projections for several sets of computational phantoms, including adult male and female and pregnant patients. Dose calculations from CT scans with TCM are prepared by appropriately weighting the existing dose data. Longitudinal TCM doses can be obtained by weighting the dose at the z-axis scan position by the relative tube current at that position. Rotational TCM doses are weighted using the relative organ doses from the principle projections as a function of the current at the rotational angle. Significant dose reductions of 15% to 25% to fetal tissues are found from simulations of longitudinal TCM schemes to pregnant patients of different gestational ages. Weighting factors for each organ in rotational TCM schemes applied to adult male and female patients have also been found. As the application of TCM techniques becomes more prevalent, the need for including TCM in CT dose estimates will necessarily increase. (author)
International Nuclear Information System (INIS)
Sato, Kaoru; Endo, Akira; Saito, Kimiaki
2008-10-01
This report presents a complete set of conversion coefficients of organ doses and effective doses calculated for external photon exposure using five Japanese adult voxel phantoms developed at the Japan Atomic Energy Agency (JAEA). At the JAEA, high-resolution Japanese voxel phantoms have been developed to clarify the variation of organ doses due to the anatomical characteristics of Japanese, and three male phantoms (JM, JM2 and Otoko) and two female phantoms (JF and Onago) have been constructed up to now. The conversion coefficients of organ doses and effective doses for the five voxel phantoms have been calculated for six kinds of idealized irradiation geometries from monoenergetic photons ranging from 0.01 to 10 MeV using EGS4, a Monte Carlo code for the simulation of coupled electron-photon transport. The dose conversion coefficients are given as absorbed dose and effective dose per unit air-kerma free-in-air, and are presented in tables and figures. The calculated dose conversion coefficients are compared with those of voxel phantoms based on the Caucasian and the recommended values in ICRP74 in order to discuss (1) variation of organ dose due to the body size and individual anatomy, such as position and shape of organs, and (2) effect of posture on organ doses. The present report provides valuable data to study the influence of the body characteristics of Japanese upon the organ doses and to discuss developing reference Japanese and Asian phantoms. (author)
International Nuclear Information System (INIS)
Ishimaru, Toranosuke; Otake, Masanori; Ichimaru, Michito; Mikami, Motoko.
1982-07-01
Analysis of the relationship of the incidence of leukemia to gamma and neutron dose among atomic bomb survivors until 1971 has been reported previously by RERF. The present inquiry was prompted by the extension of case finding to 1978 and by the recent availability of new dose estimates for this fixed cohort. It is focused on the relationship of absorbed marrow dose of gamma rays and neutrons to the incidence of two types of leukemia in the fixed cohort of A-bomb survivors and their controls, the Life Span Study extended sample, in the period October 1950-December 1978. Three dose-response models have been fitted to the data on acute leukemia and chronic granulocytic leukemia. The relationship of the incidence of acute leukemia to gamma and neutron dose again suggests that the ''best'' fitting model involves a dependence on the square of the gamma dose and a linear dependence on neutrons. The estimated relative biological effectiveness (RBE) of neutrons in the induction of acute leukemia is approximately 44/√Dn(Dn = neutron dose) under this model. Based on the 95% confidence limits of the estimated RBE, the risk of this disease is estimated as 0.0026 - 0.0072 cases per million person-years per rem 2 of marrow dose. This analysis has failed, however, to produce a significant dose-response function for the incidence of chronic granulocytic leukemia in relation to the two kinds of radiation. (author)
Radioimmunotherapy. Dose calculation and radionuclides used in treatment
International Nuclear Information System (INIS)
Savolainen, S.
1995-10-01
In radioimmunotherapy (RIT) monoclonal antibodies to cancer-associated antigens can be utilized for the transport of therapeutic radioisotopes to cancer cells. Intravenous administration of radiolabelled antibody is a potentially curative form of therapy in hematological amignancies as circulating antibodies have easy access to tumour sites. Intravenous RIT is less effective in the treatment of solid tumours because of the low fractional uptake of the injected dose, particularly in the central parts of tumours. In solid tumours more promising results have been achieved by local RIT applications. The choice of radiation - α, β or γ - will depend of the characteristics of the tumour. The importance of radiation delivered by Auger electrons has been largely underestimated in the past, but recent research has resulted in a remarkable reassessment of this issue significantly influencing the selection of radioisotopes for RIT. Research is now being focused on the therapeutic aspects of different isotopes and microdosimetric problems. There are now good prospects of RIT becoming an important form of cancer treatment before year 2000. (orig.) (78 refs., 3 figs., 1 tab.)
International Nuclear Information System (INIS)
Allam, Kh. A.
2017-01-01
In this work, a new methodology is developed based on Monte Carlo simulation for tunnels and mines external dose calculation. Tunnels external dose evaluation model of a cylindrical shape of finite thickness with an entrance and with or without exit. A photon transportation model was applied for exposure dose calculations. A new software based on Monte Carlo solution was designed and programmed using Delphi programming language. The variation of external dose due to radioactive nuclei in a mine tunnel and the corresponding experimental data lies in the range 7.3 19.9%. The variation of specific external dose rate with position in, tunnel building material density and composition were studied. The given new model has more flexible for real external dose in any cylindrical tunnel structure calculations. (authors)
Energy Technology Data Exchange (ETDEWEB)
Shapiro, A; Lin, B I [Cincinnati Univ., Ohio (USA). Dept. of Chemical and Nuclear Engineering; Windham, J P; Kereiakes, J G
1976-07-01
..gamma.. flux density and dose rate distributions have been calculated about implantable californium-252 sources for an infinite tissue medium. Point source flux densities as a function of energy and position were obtained from a discrete-ordinates calculation, and the flux densities were multiplied by their corresponding kerma factors and added to obtain point source dose rates. The point dose rates were integrated over the line source to obtain line dose rates. Container attenuation was accounted for by evaluating the point dose rate as a function of platinum thickness. Both primary and secondary flux densities and dose rates are presented. The agreement with an independent Monte Carlo calculation was excellent. The data presented should be useful for the design of new source configurations.
Tensit - a simulation tool for migration, risk and dose calculations
International Nuclear Information System (INIS)
Jones, J.; Kautsky, U.; Vahlund, C.F.
2004-01-01
During the next years the Swedish Nuclear Fuel and Waste Management Co (SKB) performs site investigations for a future repository of spent nuclear fuel. The repository will be situated in crystalline rock at a depth of approximately 500 m. Novel methods based on systems and landscape ecology are developed to understand the interacting mechanisms and finally, to model radionuclide migration in the biosphere using site specific data. These models and methods are later used as part of the overall safety assessment for the repository where also migration in the near field and in the bedrock is considered. In the present paper, a newly developed probabilistic simulation package, TENSIT, is presented. The package is based on pre-existing codes (Matlab, Simulink and the probabilistic engine-at-risk) and is capable of performing radionuclide migration calculations both for the repository and the biosphere. Hence, a platform independent, transparent (well documented and intuitive on a model scale), thoroughly supported, efficient and user friendly (graphical interface for the modeler) code can be developed at a fairly low cost. Comparisons with other codes used for compartment based biosphere modelling and the PSACOIN Level 1B exercise shows on a good agreement on the application scale. Moreover, by basing the package on continuously maintained, pre-existing codes, potential risks associated with a less spread software may be avoided. In addition to the compartment based models based on transfer factors, TENSIT is also able to handle the more complex ecosystem models (based on flow of carbon and nutrients) either separately or in combination with the compartment models. Within the project, biosphere migration calculations have been performed using TENSIT for a watershed in the Forsmark area (one of the studied sites). In this simulation, data from the ongoing site investigation program has been used to define the based model. (author)
International Nuclear Information System (INIS)
Strenge, D.L.; Watson, E.C.; Houston, J.R.
1975-06-01
A computer program, SUBDOSA, was developed for calculating external γ and β doses to individuals from the accidental release of radionuclides to the atmosphere. Characteristics of SUBDOSA are: doses from both γ and β radiation are calculated as a function of depth in tissue, summed and reported as skin, eye, gonadal, and total body dose; doses are calculated for releases within each of several release time intervals and nuclide inventories and atmospheric dispersion conditions are considered for each time interval; radioactive decay is considered during the release and/or transit using a chain decay scheme with branching to account for transitions to and from isomeric states; the dose from gamma radiation is calculated using a numerical integration technique to account for the finite size of the plume; and the program computes and lists the normalized air concentrations at ground level as a function of distance from the point of release. (auth)
Comparison of EGS4 and MCNP Monte Carlo codes when calculating radiotherapy depth doses.
Love, P A; Lewis, D G; Al-Affan, I A; Smith, C W
1998-05-01
The Monte Carlo codes EGS4 and MCNP have been compared when calculating radiotherapy depth doses in water. The aims of the work were to study (i) the differences between calculated depth doses in water for a range of monoenergetic photon energies and (ii) the relative efficiency of the two codes for different electron transport energy cut-offs. The depth doses from the two codes agree with each other within the statistical uncertainties of the calculations (1-2%). The relative depth doses also agree with data tabulated in the British Journal of Radiology Supplement 25. A discrepancy in the dose build-up region may by attributed to the different electron transport algorithims used by EGS4 and MCNP. This discrepancy is considerably reduced when the improved electron transport routines are used in the latest (4B) version of MCNP. Timing calculations show that EGS4 is at least 50% faster than MCNP for the geometries used in the simulations.
International Nuclear Information System (INIS)
Monteiro, E.
2004-01-01
The aimed of this work consists of evaluating the influence of the secondary contributions of dose (thermal neutrons dose, epithermal neutrons dose, fast neutrons dose and photon dose) in treatment planning with BNCT. MCNP4B Code was used to calculate RBE-Gy doses through the irradiation of the modified Snyder head head phantom.A reduction of the therapeutical gain of monoenergetic neutron beans was observed in non invasive treatments, provoked for the predominance of the fast neutron dose component in the skin, showing that the secondary contributions of dose can contribute more in the direction to raise the dose in the fabric healthy that in the tumor, thus reducing the treatment efficiency. (author)
International Nuclear Information System (INIS)
Hung, Tran Van; Satoh, Daiki; Takahashi, Fumiaki; Tsuda, Shuichi; Endo, Akira; Saito, Kimiaki; Yamaguchi, Yasuhiro
2005-02-01
Age-dependent dose conversion coefficients for external exposure to photons emitted by radionuclides uniformly distributed in air were calculated. The size of the source region in the calculation was assumed to be effectively semi-infinite in extent. Firstly, organ doses were calculated with a series of age-specific MIRD-5 type phantoms using MCNP code, a Monte Carlo transport code. The calculations were performed for mono-energetic photon sources of twelve energies from 10 keV to 5 MeV and for phantoms of newborn, 1, 5, 10 and 15 years, and adult. Then, the effective doses to the different age-phantoms from the mono-energetic photon sources were estimated based on the obtained organ doses. The calculated effective doses were used to interpolate the conversion coefficients of the effective doses for 160 radionuclides, which are important for dose assessment of nuclear facilities. In the calculation, energies and intensities of emitted photons from radionuclides were taken from DECDC, a recent compilation of decay data for radiation dosimetry developed at JAERI. The results are tabulated in the form of effective dose per unit concentration and time (Sv per Bq s m -3 ). (author)
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)
Hot particle dose calculations using the computer code VARSKIN Mod 2
International Nuclear Information System (INIS)
Durham, J.S.
1991-01-01
The only calculational model recognised by the Nuclear Regulatory Commission (NRC) for hot particle dosimetry is VARSKIN Mod 1. Because the code was designed to calculate skin dose from distributed skin contamination and not hot particles, it is assumed that the particle has no thickness and, therefore, that no self-absorption occurs within the source material. For low energy beta particles such as those emitted from 60 Co, a significant amount of self-shielding occurs in hot particles and VARSKIN Mod 1 overestimates the skin dose. In addition, the presence of protective clothing, which will reduce the calculated skin dose for both high and low energy beta emitters, is not modelled in VARSKIN Mod 1. Finally, there is no provision in VARSKIN Mod 1 to calculate the gamma contribution to skin dose from radionuclides that emit both beta and gamma radiation. The computer code VARSKIN Mod 1 has been modified to model three-dimensional sources, insertion of layers of protective clothing between the source and skin, and gamma dose from appropriate radionuclides. The new code, VARSKIN Mod 2, is described and the sensitivity of the calculated dose to source geometry, diameter, thickness, density, and protective clothing thickness are discussed. Finally, doses calculated using VARSKIN Mod 2 are compared to doses measured from hot particles found in nuclear power plants. (author)
[Comparison of dose calculation algorithms in stereotactic radiation therapy in lung].
Tomiyama, Yuki; Araki, Fujio; Kanetake, Nagisa; Shimohigashi, Yoshinobu; Tominaga, Hirofumi; Sakata, Jyunichi; Oono, Takeshi; Kouno, Tomohiro; Hioki, Kazunari
2013-06-01
Dose calculation algorithms in radiation treatment planning systems (RTPSs) play a crucial role in stereotactic body radiation therapy (SBRT) in the lung with heterogeneous media. This study investigated the performance and accuracy of dose calculation for three algorithms: analytical anisotropic algorithm (AAA), pencil beam convolution (PBC) and Acuros XB (AXB) in Eclipse (Varian Medical Systems), by comparison against the Voxel Monte Carlo algorithm (VMC) in iPlan (BrainLab). The dose calculations were performed with clinical lung treatments under identical planning conditions, and the dose distributions and the dose volume histogram (DVH) were compared among algorithms. AAA underestimated the dose in the planning target volume (PTV) compared to VMC and AXB in most clinical plans. In contrast, PBC overestimated the PTV dose. AXB tended to slightly overestimate the PTV dose compared to VMC but the discrepancy was within 3%. The discrepancy in the PTV dose between VMC and AXB appears to be due to differences in physical material assignments, material voxelization methods, and an energy cut-off for electron interactions. The dose distributions in lung treatments varied significantly according to the calculation accuracy of the algorithms. VMC and AXB are better algorithms than AAA for SBRT.
A fast dose calculation method based on table lookup for IMRT optimization
International Nuclear Information System (INIS)
Wu Qiuwen; Djajaputra, David; Lauterbach, Marc; Wu Yan; Mohan, Radhe
2003-01-01
This note describes a fast dose calculation method that can be used to speed up the optimization process in intensity-modulated radiotherapy (IMRT). Most iterative optimization algorithms in IMRT require a large number of dose calculations to achieve convergence and therefore the total amount of time needed for the IMRT planning can be substantially reduced by using a faster dose calculation method. The method that is described in this note relies on an accurate dose calculation engine that is used to calculate an approximate dose kernel for each beam used in the treatment plan. Once the kernel is computed and saved, subsequent dose calculations can be done rapidly by looking up this kernel. Inaccuracies due to the approximate nature of the kernel in this method can be reduced by performing scheduled kernel updates. This fast dose calculation method can be performed more than two orders of magnitude faster than the typical superposition/convolution methods and therefore is suitable for applications in which speed is critical, e.g., in an IMRT optimization that requires a simulated annealing optimization algorithm or in a practical IMRT beam-angle optimization system. (note)
International Nuclear Information System (INIS)
2000-01-01
The guide sets out the mathematical definitions and principles involved in the calculation of the equivalent dose and the effective dose, and the instructions concerning the application of the maximum values of these quantities. further, for monitoring the dose caused by internal radiation, the guide defines the limits derived from annual dose limits (the Annual Limit on Intake and the Derived Air Concentration). Finally, the guide defines the operational quantities to be used in estimating the equivalent dose and the effective dose, and also sets out the definitions of some other quantities and concepts to be used in monitoring radiation exposure. The guide does not include the calculation of patient doses carried out for the purposes of quality assurance
Energy Technology Data Exchange (ETDEWEB)
NONE
2000-07-01
The guide sets out the mathematical definitions and principles involved in the calculation of the equivalent dose and the effective dose, and the instructions concerning the application of the maximum values of these quantities. further, for monitoring the dose caused by internal radiation, the guide defines the limits derived from annual dose limits (the Annual Limit on Intake and the Derived Air Concentration). Finally, the guide defines the operational quantities to be used in estimating the equivalent dose and the effective dose, and also sets out the definitions of some other quantities and concepts to be used in monitoring radiation exposure. The guide does not include the calculation of patient doses carried out for the purposes of quality assurance.
International Nuclear Information System (INIS)
Bergstroem, U.
1983-05-01
The turnover of radioactive matter entering the biosphere with groundwater has been studied with regard to exposure and doses to critical groups and populations. Two main recipients, a well and a lake, have been considered for the inflow of groundwaterborne nuclides. Mathematical models of a set of coupled ecosystems on regional, intermediate and global levels have been used for calculations of doses. The intermediate system refers to the Baltic Sea. The mathematical treatment of the model is based upon compartment theory with first order kinetics and also includes products in decay chains. The time-dependent exposures have been studied for certain long-lived nuclides of radiological interest in waste from disposed fuel. Dose and dose commitment have been calculated for different episodes for inflow to the biosphere. (author)
Calculation of radiation dose rate arisen from radionuclide contained in building materials
International Nuclear Information System (INIS)
Lai Tien Thinh; Nguyen Hao Quang
2008-01-01
This paper presents some results that we used MCNP5 program to calculate radiation dose rate arisen from radionuclide in building materials. Since then, the limits of radionuclide content in building materials are discussed. The calculation results by MCNP are compared with those calculated by analytical method. (author)
A simple formula for depth dose calculation for Co-60 teletherapy beam dosimetry
International Nuclear Information System (INIS)
Tripathi, U.B.; Kelkar, N.Y.
1979-01-01
Knowledge of dose at all points of interest in the plane of tumour is essential for treatment planning. A very simple formula for scatter dose calculation along the central axis of a Co-60 beam has been derived. This formula uses primary dose at depth d, scatter air ratio at the depth of maximum ionisation and the effective depth of the volume, irradiating the medium. The method for calculation of percentage depth dose at any point in the principal plane has been explained in detail. The simple form of the formulation will help in improving the treatment plans for treatments of lesions using Co-60 teletherapy machines. (orig.) [de
Energy Technology Data Exchange (ETDEWEB)
Frassoni, F; Bacigalupo, A [Ospedale San Martino (Italy). Centro Trapianti Midollo Osseo; Scarpati, D [Univ. di Genova (Italy). Ist. di Radiologia; and others
1989-10-01
One-hundred and five patients undergoing allo-geneic bone marrow transplantation (BMT) for acute myeloid leukaemia (AML) (n=61) and chronic myeloid leukaemia (n=44) were analysed for risk factors associated with relapse. All patients received marrow from an HLA identical sibling after preparation with cyclophosphamide 120 mg/kg and total body irradiation (TBI) 330 cGy on each of the three days prior to transplantation. A multivariate Cox analysis indicated that a lower TBI dose (less than 990 cGy) was the most significant factor associated with relapse and the second most important factor associated with recurrence of leukaemia was the absence of chronic graft-versus-host-disease (cGvHD). Actuarial relapse incidence was 62%, 28% and 18% for patients with no, limited or extensive chronic GvHD respectively. However, chronic GvHD had no significant impact on survival. Combined stratification for TBI dose and cGvHD showed that the dose effect of TBI on relapse was evident both in patients with and without cGvHD. Chronic GvHD influenced the risk of relapse only in patients receiving less than 990 cGy. These results suggest that a higher dose of TBI, within this schedule, produced long-term disease-free survival in the majority of AMLs and CMLs. Minor radiobiological side effects were experienced, but a small reduction of the dose may significantly increase the risk of relapse. (author).
International Nuclear Information System (INIS)
Frassoni, F.; Bacigalupo, A.; Scarpati, D.
1989-01-01
One-hundred and five patients undergoing allo-geneic bone marrow transplantation (BMT) for acute myeloid leukaemia (AML) (n=61) and chronic myeloid leukaemia (n=44) were analysed for risk factors associated with relapse. All patients received marrow from an HLA identical sibling after preparation with cyclophosphamide 120 mg/kg and total body irradiation (TBI) 330 cGy on each of the three days prior to transplantation. A multivariate Cox analysis indicated that a lower TBI dose (less than 990 cGy) was the most significant factor associated with relapse and the second most important factor associated with recurrence of leukaemia was the absence of chronic graft-versus-host-disease (cGvHD). Actuarial relapse incidence was 62%, 28% and 18% for patients with no, limited or extensive chronic GvHD respectively. However, chronic GvHD had no significant impact on survival. Combined stratification for TBI dose and cGvHD showed that the dose effect of TBI on relapse was evident both in patients with and without cGvHD. Chronic GvHD influenced the risk of relapse only in patients receiving less than 990 cGy. These results suggest that a higher dose of TBI, within this schedule, produced long-term disease-free survival in the majority of AMLs and CMLs. Minor radiobiological side effects were experienced, but a small reduction of the dose may significantly increase the risk of relapse. (author)
Calculation of the radial dose distribution around the trajectory of an ion
International Nuclear Information System (INIS)
Pretzsch, G.
1979-01-01
The dose caused in polyester by incoming protons, alpha beams, 127 I ions, and 16 O ions has been calculated as a function of the distance perpendicularly to their trajectory. Based on simplified assumptions regarding the binding state of target electrons, emission of secondary electrons and their propagation in matter, it has been found that the dose depends on the distance to the ion trajectory (R) in the form Rsup(-l), l being about 2. The calculated radial dose distributions agree well with values calculated or measured by other authors
International Nuclear Information System (INIS)
Namestek, L.; Khorvat, D; Shvets, J.; Kunz, Eh.
1976-01-01
A method of calculating the doses of external and internal person irradiation in the nuclear power plant vicinity under conditions of normal operation and accident situations has been described. The main difference between the above method and methods used up to now is the use of a new antropomorphous representation of a human body model together with all the organs. The antropomorphous model of human body and its organs is determined as a set of simple solids, coordinates of disposistion of the solids, sizes, masses, densities and composition corresponding the genuine organs. The use of the Monte-Carlo method is the second difference. The results of the calculations according to the model suggested can be used for determination: a critical group of inhabitans under conditions of normal plant operation; groups of inhabitants most subjected to irradiation in the case of possible accident; a critical sector with a maximum collective dose in the case of an accident; a critical radioisotope favouring the greatest contribution to an individual equivalent dose; critical irradiation ways promoting a maximum contribution to individual equivalent doses; cumulative collective doses for the whole region or for a chosen part of the region permitting to estimate a population dose. The consequent method evoluation suggests the development of separate units of the calculationg program, critical application and the selection of input data of physical, plysiological and ecological character and improvement of the calculated program for the separate concrete events [ru
Effects of microdistribution of tritium on dose calculations
International Nuclear Information System (INIS)
Prestwich, W.V.; Kwok, C.S.; Nunes, J.
1992-06-01
Literature and data pertaining to the microdosimetry, relative biological effectiveness, subcellular distribution, organ uptake and retention for organically-bound tritium are reviewed. The quality factor for the electron degradation spectrum associated with the radiation field of tritium β-rays in water was calculated. The value was found to be 1.9 ± .2. A related experimental measure of quality with value 1.6 ± .2 and an estimate of 1.3 based on simulation studies are cited. The average value for relative biological effectiveness for a data base of 55 values was found to be 1.8 ± .1. The influence of reference radiation, in vivo versus in vitro methodologies, and the use of tritiated thymidine or tritiated water are discussed. A methodology designed to estimate the effects of subcellular distribution is described and a suitable parameter, the localization factor defined. Estimates of this factor are made for both nuclear-bound and organically-bound tritium. Values of 4 and 1.5 respectively are suggested. Organ uptake studies in rodents following long-term feeding of organically-bound tritium are compared. The tritium is found to be unequally distributed among the tissues studied. The highest specific activity occurs in liver, with the lowest in femur. The specific activity of tritium in tissue-free water slightly exceeds that of organically-bound tritium in liver. Retention studies reveal a three-component exponential decrease of organically-bound tritium. No discernible trends of the periods of the three components with specific organs could be established. Average values of the periods are 1.2 ± .2, 10 ± 2, and 65 ± 8 days. It is concluded that specific enhancement of radiobiological effectiveness due to incorporation of tritium in DNA does probably not occur. The radiotoxicological impact of organically-bound tritium could warrant the use of a radiation weighing factor between 2 and 3
A bone marrow toxicity model for 223Ra alpha-emitter radiopharmaceutical therapy
International Nuclear Information System (INIS)
Hobbs, Robert F; Song Hong; Sgouros, George; Watchman, Christopher J; Bolch, Wesley E; Aksnes, Anne-Kirsti; Ramdahl, Thomas; Flux, Glenn D
2012-01-01
Ra-223, an α-particle emitting bone-seeking radionuclide, has recently been used in clinical trials for osseous metastases of prostate cancer. We investigated the relationship between absorbed fraction-based red marrow dosimetry and cell level-dosimetry using a model that accounts for the expected localization of this agent relative to marrow cavity architecture. We show that cell level-based dosimetry is essential to understanding potential marrow toxicity. The GEANT4 software package was used to create simple spheres representing marrow cavities. Ra-223 was positioned on the trabecular bone surface or in the endosteal layer and simulated for decay, along with the descendants. The interior of the sphere was divided into cell-size voxels and the energy was collected in each voxel and interpreted as dose cell histograms. The average absorbed dose values and absorbed fractions were also calculated in order to compare those results with previously published values. The absorbed dose was predominantly deposited near the trabecular surface. The dose cell histogram results were used to plot the percentage of cells that received a potentially toxic absorbed dose (2 or 4 Gy) as a function of the average absorbed dose over the marrow cavity. The results show (1) a heterogeneous distribution of cellular absorbed dose, strongly dependent on the position of the cell within the marrow cavity; and (2) that increasing the average marrow cavity absorbed dose, or equivalently, increasing the administered activity resulted in only a small increase in potential marrow toxicity (i.e. the number of cells receiving more than 4 or 2 Gy), for a range of average marrow cavity absorbed doses from 1 to 20 Gy. The results from the trabecular model differ markedly from a standard absorbed fraction method while presenting comparable average dose values. These suggest that increasing the amount of radioactivity may not substantially increase the risk of toxicity, a result unavailable to the
International Nuclear Information System (INIS)
Iwasaki, Akira
1993-01-01
A method of making 60 Co γ-ray primary and scatter dose spread arrays in water is described. The primary dose spread array is made using forward and backward primary dose spread equations (h 1 and h 2 ), where both equations contain a laterally spread primary dose equation (G), made from measured dose data in a cork phantom. The scatter dose spread array is made using differential scatter-maximum ratio (dSMR) and differential backscatter factor (dBSF) equations (k 1 and k 2 ), where both equations are made to be continuous on the boundary. Primary and scatter dose calculations are performed along the beam axis in layered cork heterogeneous phantoms. It is found, even for 60 Co γ-rays, that when a small tumor in the lung is irradiated with a field that just surrounds the tumor, the beam entrance surface and lateral side of the tumor may obtain no therapeutic dose, because of loss of longitudinal and lateral electronic equilibrium, and when a large tumor in the lung is irradiated with a field just surrounding the tumor, the lateral side of the tumor may obtain no therapeutic dose due to loss of lateral electronic equilibrium. (author)
Point kernels and superposition methods for scatter dose calculations in brachytherapy
International Nuclear Information System (INIS)
Carlsson, A.K.
2000-01-01
Point kernels have been generated and applied for calculation of scatter dose distributions around monoenergetic point sources for photon energies ranging from 28 to 662 keV. Three different approaches for dose calculations have been compared: a single-kernel superposition method, a single-kernel superposition method where the point kernels are approximated as isotropic and a novel 'successive-scattering' superposition method for improved modelling of the dose from multiply scattered photons. An extended version of the EGS4 Monte Carlo code was used for generating the kernels and for benchmarking the absorbed dose distributions calculated with the superposition methods. It is shown that dose calculation by superposition at and below 100 keV can be simplified by using isotropic point kernels. Compared to the assumption of full in-scattering made by algorithms currently in clinical use, the single-kernel superposition method improves dose calculations in a half-phantom consisting of air and water. Further improvements are obtained using the successive-scattering superposition method, which reduces the overestimates of dose close to the phantom surface usually associated with kernel superposition methods at brachytherapy photon energies. It is also shown that scatter dose point kernels can be parametrized to biexponential functions, making them suitable for use with an effective implementation of the collapsed cone superposition algorithm. (author)
Independent dose calculation in IMRT for the Tps Iplan using the Clarkson modified integral
International Nuclear Information System (INIS)
Adrada, A.; Tello, Z.; Garrigo, E.; Venencia, D.
2014-08-01
Intensity-Modulated Radiation Therapy (IMRT) treatments require a quality assurance (Q A) specific patient before delivery. These controls include the experimental verification in dose phantom of the total plan as well as dose distributions. The use of independent dose calculation (IDC) is used in 3D-Crt treatments; however its application in IMRT requires the implementation of an algorithm that allows considering a non-uniform intensity beam. The purpose of this work was to develop IDC software in IMRT with MLC using the algorithm proposed by Kung (Kung et al. 2000). The software was done using Matlab programming. The Clarkson modified integral was implemented on each flowing, applying concentric rings for the dose determination. From the integral of each field was calculated the dose anywhere. One time finished a planning; all data are exported to a phantom where a Q A plan is generated. On this is calculated the half dose in a representative volume of the ionization chamber and the dose at the center of it. Until now 230 IMRT planning were analyzed carried out ??in the treatment planning system (Tps) Iplan. For each one of them Q A plan was generated, were calculated and compared calculated dose with the Tps, IDC system and measurement with ionization chamber. The average difference between measured and calculated dose with the IDC system was 0.4% ± 2.2% [-6.8%, 6.4%]. The difference between the measured and the calculated doses by the pencil-beam algorithm (Pb) of Tps was 2.6% ± 1.41% [-2.0%, 5.6%] and with the Monte Carlo algorithm was 0.4% ± 1.5% [-4.9%, 3.7%]. The differences of the carried out software are comparable to the obtained with the ionization chamber and Tps in Monte Carlo mode. (author)
Dose calculation methods in photon beam therapy using energy deposition kernels
International Nuclear Information System (INIS)
Ahnesjoe, A.
1991-01-01
The problem of calculating accurate dose distributions in treatment planning of megavoltage photon radiation therapy has been studied. New dose calculation algorithms using energy deposition kernels have been developed. The kernels describe the transfer of energy by secondary particles from a primary photon interaction site to its surroundings. Monte Carlo simulations of particle transport have been used for derivation of kernels for primary photon energies form 0.1 MeV to 50 MeV. The trade off between accuracy and calculational speed has been addressed by the development of two algorithms; one point oriented with low computional overhead for interactive use and one for fast and accurate calculation of dose distributions in a 3-dimensional lattice. The latter algorithm models secondary particle transport in heterogeneous tissue by scaling energy deposition kernels with the electron density of the tissue. The accuracy of the methods has been tested using full Monte Carlo simulations for different geometries, and found to be superior to conventional algorithms based on scaling of broad beam dose distributions. Methods have also been developed for characterization of clinical photon beams in entities appropriate for kernel based calculation models. By approximating the spectrum as laterally invariant, an effective spectrum and dose distribution for contaminating charge particles are derived form depth dose distributions measured in water, using analytical constraints. The spectrum is used to calculate kernels by superposition of monoenergetic kernels. The lateral energy fluence distribution is determined by deconvolving measured lateral dose distributions by a corresponding pencil beam kernel. Dose distributions for contaminating photons are described using two different methods, one for estimation of the dose outside of the collimated beam, and the other for calibration of output factors derived from kernel based dose calculations. (au)
Energy Technology Data Exchange (ETDEWEB)
Koivunoro, Hanna; Seppaelae, Tiina; Uusi-Simola, Jouni; Merimaa, Katja; Savolainen, Sauli [Department of Physics, POB 64, FI-00014 University of Helsinki (Finland); Kotiluoto, Petri; Seren, Tom; Auterinen, Iiro [VTT Technical Research Centre of Finland, Espoo, POB 1000, FI-02044 VTT (Finland); Kortesniemi, Mika, E-mail: hanna.koivunoro@helsinki.f [HUS Helsinki Medical Imaging Center, University of Helsinki, POB 340, FI-00029 HUS (Finland)
2010-06-21
In this paper, the accuracy of dose planning calculations for boron neutron capture therapy (BNCT) of brain and head and neck cancer was studied at the FiR 1 epithermal neutron beam. A cylindrical water phantom and an anthropomorphic head phantom were applied with two beam aperture-to-surface distances (ASD). The calculations using the simulation environment for radiation application (SERA) treatment planning system were compared to neutron activation measurements with Au and Mn foils, photon dose measurements with an ionization chamber and the reference simulations with the MCNP5 code. Photon dose calculations using SERA differ from the ionization chamber measurements by 2-13% (disagreement increased along the depth in the phantom), but are in agreement with the MCNP5 calculations within 2%. The {sup 55}Mn(n,{gamma}) and {sup 197}Au(n,{gamma}) reaction rates calculated using SERA agree within 10% and 8%, respectively, with the measurements and within 5% with the MCNP5 calculations at depths >0.5 cm from the phantom surface. The {sup 55}Mn(n,{gamma}) reaction rate represents the nitrogen and boron depth dose within 1%. Discrepancy in the SERA fast neutron dose calculation (of up to 37%) is corrected if the biased fast neutron dose calculation option is not applied. Reduced voxel cell size ({<=}0.5 cm) improves the SERA calculation accuracy on the phantom surface. Despite the slight overestimation of the epithermal neutrons and underestimation of the thermal neutrons in the beam model, neutron calculation accuracy with the SERA system is sufficient for reliable BNCT treatment planning with the two studied treatment distances. The discrepancy between measured and calculated photon dose remains unsatisfactorily high for depths >6 cm from the phantom surface. Increasing discrepancy along the phantom depth is expected to be caused by the inaccurately determined effective point of the ionization chamber.
International Nuclear Information System (INIS)
2002-01-01
Calculations with the quadratic lineal model for medium rate using the equation dose-effect. Several calculations for system of low dose rate brachytherapy plus teletherapy, calculations for brachytherapy with medium dose rate together with teletherapy, dose for fraction and the one numbers of fractions in medium rate
Dose calculation with respiration-averaged CT processed from cine CT without a respiratory surrogate
International Nuclear Information System (INIS)
Riegel, Adam C.; Ahmad, Moiz; Sun Xiaojun; Pan Tinsu
2008-01-01
Dose calculation for thoracic radiotherapy is commonly performed on a free-breathing helical CT despite artifacts caused by respiratory motion. Four-dimensional computed tomography (4D-CT) is one method to incorporate motion information into the treatment planning process. Some centers now use the respiration-averaged CT (RACT), the pixel-by-pixel average of the ten phases of 4D-CT, for dose calculation. This method, while sparing the tedious task of 4D dose calculation, still requires 4D-CT technology. The authors have recently developed a means to reconstruct RACT directly from unsorted cine CT data from which 4D-CT is formed, bypassing the need for a respiratory surrogate. Using RACT from cine CT for dose calculation may be a means to incorporate motion information into dose calculation without performing 4D-CT. The purpose of this study was to determine if RACT from cine CT can be substituted for RACT from 4D-CT for the purposes of dose calculation, and if increasing the cine duration can decrease differences between the dose distributions. Cine CT data and corresponding 4D-CT simulations for 23 patients with at least two breathing cycles per cine duration were retrieved. RACT was generated four ways: First from ten phases of 4D-CT, second, from 1 breathing cycle of images, third, from 1.5 breathing cycles of images, and fourth, from 2 breathing cycles of images. The clinical treatment plan was transferred to each RACT and dose was recalculated. Dose planes were exported at orthogonal planes through the isocenter (coronal, sagittal, and transverse orientations). The resulting dose distributions were compared using the gamma (γ) index within the planning target volume (PTV). Failure criteria were set to 2%/1 mm. A follow-up study with 50 additional lung cancer patients was performed to increase sample size. The same dose recalculation and analysis was performed. In the primary patient group, 22 of 23 patients had 100% of points within the PTV pass γ criteria
A GPU implementation of a track-repeating algorithm for proton radiotherapy dose calculations
International Nuclear Information System (INIS)
Yepes, Pablo P; Mirkovic, Dragan; Taddei, Phillip J
2010-01-01
An essential component in proton radiotherapy is the algorithm to calculate the radiation dose to be delivered to the patient. The most common dose algorithms are fast but they are approximate analytical approaches. However their level of accuracy is not always satisfactory, especially for heterogeneous anatomical areas, like the thorax. Monte Carlo techniques provide superior accuracy; however, they often require large computation resources, which render them impractical for routine clinical use. Track-repeating algorithms, for example the fast dose calculator, have shown promise for achieving the accuracy of Monte Carlo simulations for proton radiotherapy dose calculations in a fraction of the computation time. We report on the implementation of the fast dose calculator for proton radiotherapy on a card equipped with graphics processor units (GPUs) rather than on a central processing unit architecture. This implementation reproduces the full Monte Carlo and CPU-based track-repeating dose calculations within 2%, while achieving a statistical uncertainty of 2% in less than 1 min utilizing one single GPU card, which should allow real-time accurate dose calculations.
Directory of Open Access Journals (Sweden)
Takahashi Wataru
2012-02-01
Full Text Available Abstract Background The purpose of this study was to compare dose distributions from three different algorithms with the x-ray Voxel Monte Carlo (XVMC calculations, in actual computed tomography (CT scans for use in stereotactic radiotherapy (SRT of small lung cancers. Methods Slow CT scan of 20 patients was performed and the internal target volume (ITV was delineated on Pinnacle3. All plans were first calculated with a scatter homogeneous mode (SHM which is compatible with Clarkson algorithm using Pinnacle3 treatment planning system (TPS. The planned dose was 48 Gy in 4 fractions. In a second step, the CT images, structures and beam data were exported to other treatment planning systems (TPSs. Collapsed cone convolution (CCC from Pinnacle3, superposition (SP from XiO, and XVMC from Monaco were used for recalculating. The dose distributions and the Dose Volume Histograms (DVHs were compared with each other. Results The phantom test revealed that all algorithms could reproduce the measured data within 1% except for the SHM with inhomogeneous phantom. For the patient study, the SHM greatly overestimated the isocenter (IC doses and the minimal dose received by 95% of the PTV (PTV95 compared to XVMC. The differences in mean doses were 2.96 Gy (6.17% for IC and 5.02 Gy (11.18% for PTV95. The DVH's and dose distributions with CCC and SP were in agreement with those obtained by XVMC. The average differences in IC doses between CCC and XVMC, and SP and XVMC were -1.14% (p = 0.17, and -2.67% (p = 0.0036, respectively. Conclusions Our work clearly confirms that the actual practice of relying solely on a Clarkson algorithm may be inappropriate for SRT planning. Meanwhile, CCC and SP were close to XVMC simulations and actual dose distributions obtained in lung SRT.
CT-based dose calculations and in vivo dosimetry for lung cancer treatment
International Nuclear Information System (INIS)
Essers, M.; Lanson, J.H.; Leunens, G.; Schnabel, T.; Mijnheer, B.J.
1995-01-01
Reliable CT-based dose calculations and dosimetric quality control are essential for the introduction of new conformal techniques for the treatment of lung cancer. The first aim of this study was therefore to check the accuracy of dose calculations based on CT-densities, using a simple inhomogeneity correction model, for lung cancer patients irradiated with an AP-PA treatment technique. Second, the use of diodes for absolute exit dose measurements and an Electronic Portal Imaging Device (EPID) for relative transmission dose verification was investigated for 22 and 12 patients, respectively. The measured dose values were compared with calculations performed using our 3-dimensional treatment planning system, using CT-densities or assuming the patient to be water-equivalent. Using water-equivalent calculations, the actual exit dose value under lung was, on average, underestimated by 30%, with an overall spread of 10% (1 SD). Using inhomogeneity corrections, the exit dose was, on average, overestimated by 4%, with an overall spread of 6% (1 SD). Only 2% of the average deviation was due to the inhomogeneity correction model. An uncertainty in exit dose calculation of 2.5% (1 SD) could be explained by organ motion, resulting from the ventilatory or cardiac cycle. The most important reason for the large overall spread was, however, the uncertainty involved in performing point measurements: about 4% (1 SD). This difference resulted from the systematic and random deviation in patient set-up and therefore in diode position with respect to patient anatomy. Transmission and exit dose values agreed with an average difference of 1.1%. Transmission dose profiles also showed good agreement with calculated exit dose profiles. Our study shows that, for this treatment technique, the dose in the thorax region is quite accurately predicted using CT-based dose calculations, even if a simple inhomogeneity correction model is used. Point detectors such as diodes are not suitable for exit
Energy Technology Data Exchange (ETDEWEB)
Davidson, Scott E., E-mail: sedavids@utmb.edu [Radiation Oncology, The University of Texas Medical Branch, Galveston, Texas 77555 (United States); Cui, Jing [Radiation Oncology, University of Southern California, Los Angeles, California 90033 (United States); Kry, Stephen; Ibbott, Geoffrey S.; Followill, David S. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Deasy, Joseph O. [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States); Vicic, Milos [Department of Applied Physics, University of Belgrade, Belgrade 11000 (Serbia); White, R. Allen [Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)
2016-08-15
Purpose: A dose calculation tool, which combines the accuracy of the dose planning method (DPM) Monte Carlo code and the versatility of a practical analytical multisource model, which was previously reported has been improved and validated for the Varian 6 and 10 MV linear accelerators (linacs). The calculation tool can be used to calculate doses in advanced clinical application studies. One shortcoming of current clinical trials that report dose from patient plans is the lack of a standardized dose calculation methodology. Because commercial treatment planning systems (TPSs) have their own dose calculation algorithms and the clinical trial participant who uses these systems is responsible for commissioning the beam model, variation exists in the reported calculated dose distributions. Today’s modern linac is manufactured to tight specifications so that variability within a linac model is quite low. The expectation is that a single dose calculation tool for a specific linac model can be used to accurately recalculate dose from patient plans that have been submitted to the clinical trial community from any institution. The calculation tool would provide for a more meaningful outcome analysis. Methods: The analytical source model was described by a primary point source, a secondary extra-focal source, and a contaminant electron source. Off-axis energy softening and fluence effects were also included. The additions of hyperbolic functions have been incorporated into the model to correct for the changes in output and in electron contamination with field size. A multileaf collimator (MLC) model is included to facilitate phantom and patient dose calculations. An offset to the MLC leaf positions was used to correct for the rudimentary assumed primary point source. Results: Dose calculations of the depth dose and profiles for field sizes 4 × 4 to 40 × 40 cm agree with measurement within 2% of the maximum dose or 2 mm distance to agreement (DTA) for 95% of the data
International Nuclear Information System (INIS)
Ringden, O.; Baaryd, I.; Johansson, B.
1983-01-01
Seven bone marrow transplant recipients with acute lymphoblastic leukemia receiving a mean dose rate of 0.07 Gy/min of total body irradiation towards the pelvic midpoint and the lungs had an increased (p<0.01) overall death rate of 86 per cent compared with 33 per cent among 27 patients with acute non-lymphoblastic leukemia or acute lymphoblastic leukemia treated with a mean dose rate of 0.04 Gy/min. Among the patients receiving the higher dose rate there was an increased mortality in causes related to radiation toxicity like early septicemia, interstitial pneumonitis and pulmonary fibrosis, compared with all patients receiving the lower dose rate (p<0.01) and also with 10 patients from this group with acute lymphoblastic leukemia (p<0.02). (Auth.)
International Nuclear Information System (INIS)
Kim, Jung-Ha; Hill, Robin; Kuncic, Zdenka
2012-01-01
The Monte Carlo (MC) method has proven invaluable for radiation transport simulations to accurately determine radiation doses and is widely considered a reliable computational measure that can substitute a physical experiment where direct measurements are not possible or feasible. In the EGSnrc/BEAMnrc MC codes, there are several user-specified parameters and customized transport algorithms, which may affect the calculation results. In order to fully utilize the MC methods available in these codes, it is essential to understand all these options and to use them appropriately. In this study, the effects of the electron transport algorithms in EGSnrc/BEAMnrc, which are often a trade-off between calculation accuracy and efficiency, were investigated in the buildup region of a homogeneous water phantom and also in a heterogeneous phantom using the DOSRZnrc user code. The algorithms and parameters investigated include: boundary crossing algorithm (BCA), skin depth, electron step algorithm (ESA), global electron cutoff energy (ECUT) and electron production cutoff energy (AE). The variations in calculated buildup doses were found to be larger than 10% for different user-specified transport parameters. We found that using BCA = EXACT gave the best results in terms of accuracy and efficiency in calculating buildup doses using DOSRZnrc. In addition, using the ESA = PRESTA-I option was found to be the best way of reducing the total calculation time without losing accuracy in the results at high energies (few keV ∼ MeV). We also found that although choosing a higher ECUT/AE value in the beam modelling can dramatically improve computation efficiency, there is a significant trade-off in surface dose uncertainty. Our study demonstrates that a careful choice of user-specified transport parameters is required when conducting similar MC calculations. (note)
International Nuclear Information System (INIS)
Ikenberry, T.A.; Napier, B.A.
1992-12-01
A series of scoping calculations have been undertaken to evaluate The absolute and relative contribution of different exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford site. This scoping calculation (Calculation 001) examined the contributions of the various exposure pathways associated with environmental transport and accumulation of iodine-131 in the pasture-cow-milk pathway. Addressed in this calculation were the contributions to thyroid dose of infants and adult from (1) the ingestion by dairy cattle of various feedstuffs (pasturage, silage, alfalfa hay, and grass hay) in four different feeding regimes; (2) ingestion of soil by dairy cattle; (3) ingestion of stared feed on which airborne iodine-131 had been deposited; and (4) inhalation of airborne iodine-131 by dairy cows
Sub-second pencil beam dose calculation on GPU for adaptive proton therapy.
da Silva, Joakim; Ansorge, Richard; Jena, Rajesh
2015-06-21
Although proton therapy delivered using scanned pencil beams has the potential to produce better dose conformity than conventional radiotherapy, the created dose distributions are more sensitive to anatomical changes and patient motion. Therefore, the introduction of adaptive treatment techniques where the dose can be monitored as it is being delivered is highly desirable. We present a GPU-based dose calculation engine relying on the widely used pencil beam algorithm, developed for on-line dose calculation. The calculation engine was implemented from scratch, with each step of the algorithm parallelized and adapted to run efficiently on the GPU architecture. To ensure fast calculation, it employs several application-specific modifications and simplifications, and a fast scatter-based implementation of the computationally expensive kernel superposition step. The calculation time for a skull base treatment plan using two beam directions was 0.22 s on an Nvidia Tesla K40 GPU, whereas a test case of a cubic target in water from the literature took 0.14 s to calculate. The accuracy of the patient dose distributions was assessed by calculating the γ-index with respect to a gold standard Monte Carlo simulation. The passing rates were 99.2% and 96.7%, respectively, for the 3%/3 mm and 2%/2 mm criteria, matching those produced by a clinical treatment planning system.
International Nuclear Information System (INIS)
Tachibana, Masayuki; Noguchi, Yoshitaka; Fukunaga, Jyunichi; Hirano, Naomi; Yoshidome, Satoshi; Hirose, Takaaki
2009-01-01
The monitor unit (MU) was calculated by pencil beam convolution (inhomogeneity correction algorithm: batho power law) [PBC (BPL)] which is the dose calculation algorithm based on measurement in the past in the stereotactic lung irradiation study. The recalculation was done by analytical anisotropic algorithm (AAA), which is the dose calculation algorithm based on theory data. The MU calculated by PBC (BPL) and AAA was compared for each field. In the result of the comparison of 1031 fields in 136 cases, the MU calculated by PBC (BPL) was about 2% smaller than that calculated by AAA. This depends on whether one does the calculation concerning the extension of the second electrons. In particular, the difference in the MU is influenced by the X-ray energy. With the same X-ray energy, when the irradiation field size is small, the lung pass length is long, the lung pass length percentage is large, and the CT value of the lung is low, and the difference of MU is increased. (author)
High-speed radiation dose calculations for severe accidents using INDOS
International Nuclear Information System (INIS)
Davidson, G.R.; Godin-Jacqmin, L.J.; Raines, J.C.
1992-01-01
The computer code INDOS (in-plant dose) has been developed for the high-speed calculation of in-plant radiation dose rates and doses during and/or due to a severe accident at a nuclear power plant. This paper describes the current capabilities of the code and presents the results of calculations for several severe-accident scenarios. The INDOS code can be run either as a module of MAAP, a code widely used in the nuclear industry for simulating the response of a light water reactor system during severe accidents, or as a stand-alone code using output from an alternative companion code. INDOS calculates gamma dose rates and doses in major plant compartments caused by airborne and deposited fission products released during an accident. The fission product concentrations are determined by the companion code
Kirkland, David; Whitwell, James; Deyo, James; Serex, Tessa
2007-03-05
Antimony trioxide (Sb2O3, CAS 1309-64-4) is widely used as a flame retardant synergist in a number of household products, as a fining agent in glass manufacture, and as a catalyst in the manufacture of various types of polyester plastics. It does not induce point mutations in bacteria or mammalian cells, but is able to induce chromosomal aberrations (CA) in cultured cells in vitro. Although no CA or micronuclei (MN) have been induced after acute oral dosing of mice, repeated oral dosing for 14 or 21 days resulted in increased CA in one report, but did not result in increased MN in another. In order to further investigate its in vivo genotoxicity, Sb2O3 was dosed orally to groups of rats for 21 days at 250, 500 and 1000 mg/kg day. There were no clinical signs of toxicity in the Sb2O3-exposed animals except for some reductions in body-weight gain in the top dose group. Toxicokinetic measurements in a separate study confirmed bone-marrow exposure, and at higher levels than would have been achieved by single oral dosing. Large numbers of cells were scored for CA (600 metaphases/sex group) and MN (12,000 PCE/sex group) but frequencies of CA or MN in Sb2O3-treated rats were very similar to controls, and not biologically or statistically different, at all doses. These results provide further indication that Sb2O3 is not genotoxic to the bone marrow of rodents after 21 days of oral administration at high doses close to the maximum tolerated dose.
International Nuclear Information System (INIS)
Lu Weiguo; Olivera, Gustavo H; Chen Mingli; Reckwerdt, Paul J; Mackie, Thomas R
2005-01-01
Convolution/superposition (C/S) is regarded as the standard dose calculation method in most modern radiotherapy treatment planning systems. Different implementations of C/S could result in significantly different dose distributions. This paper addresses two major implementation issues associated with collapsed cone C/S: one is how to utilize the tabulated kernels instead of analytical parametrizations and the other is how to deal with voxel size effects. Three methods that utilize the tabulated kernels are presented in this paper. These methods differ in the effective kernels used: the differential kernel (DK), the cumulative kernel (CK) or the cumulative-cumulative kernel (CCK). They result in slightly different computation times but significantly different voxel size effects. Both simulated and real multi-resolution dose calculations are presented. For simulation tests, we use arbitrary kernels and various voxel sizes with a homogeneous phantom, and assume forward energy transportation only. Simulations with voxel size up to 1 cm show that the CCK algorithm has errors within 0.1% of the maximum gold standard dose. Real dose calculations use a heterogeneous slab phantom, both the 'broad' (5 x 5 cm 2 ) and the 'narrow' (1.2 x 1.2 cm 2 ) tomotherapy beams. Various voxel sizes (0.5 mm, 1 mm, 2 mm, 4 mm and 8 mm) are used for dose calculations. The results show that all three algorithms have negligible difference (0.1%) for the dose calculation in the fine resolution (0.5 mm voxels). But differences become significant when the voxel size increases. As for the DK or CK algorithm in the broad (narrow) beam dose calculation, the dose differences between the 0.5 mm voxels and the voxels up to 8 mm (4 mm) are around 10% (7%) of the maximum dose. As for the broad (narrow) beam dose calculation using the CCK algorithm, the dose differences between the 0.5 mm voxels and the voxels up to 8 mm (4 mm) are around 1% of the maximum dose. Among all three methods, the CCK algorithm
Technical basis for beta skin dose calculations at the Y-12 Plant
International Nuclear Information System (INIS)
Thomas, J.M.; Bogard, R.S.
1994-03-01
This report describes the methods for determining shallow dose equivalent to workers at the Oak Ridge Y-12 Plant from skin contamination detected by survey instrumentation. Included is a discussion of how the computer code VARSKIN is used to calculate beta skin dose and how the code input parameters affect skin dose calculation results. A summary of Y-12 Plant specific assumptions used in performing VARSKIN calculations is presented. Derivations of contamination levels that trigger the need for skin dose assessment are given for both enriched and depleted uranium with the use of Y-12 Plant site-specific survey instruments. Department of Energy recording requirements for nonuniform exposure of the skin are illustrated with sample calculations
Dose calculation at distance of irradiation beams: case of women treated for the Hodgkin disease
International Nuclear Information System (INIS)
Poupon, E.; Alziar, I.; Vathaire, F. de; Diallo, I.; Bridier, A.; Bonniaud, G.; Lefkopoulos, D.; Ruaud, J.B.; Rousseau, V.; Kafrouni, H.
2007-01-01
The interest of precise calculation of radiation doses distributions remote areas of irradiation is to open new prospects in the knowledge of the contribution of radiotherapy in the occurrence of iatrogenic early and delayed effects. (N.C.)
Modeling for Dose Rate Calculation of the External Exposure to Gamma Emitters in Soil
International Nuclear Information System (INIS)
Allam, K. A.; El-Mongy, S. A.; El-Tahawy, M. S.; Mohsen, M. A.
2004-01-01
Based on the model proposed and developed in Ph.D thesis of the first author of this work, the dose rate conversion factors (absorbed dose rate in air per specific activity of soil in nGy.hr - 1 per Bq.kg - 1) are calculated 1 m above the ground for photon emitters of natural radionuclides uniformly distributed in the soil. This new and simple dose rate calculation software was used for calculation of the dose rate in air 1 m above the ground. Then the results were compared with those obtained by five different groups. Although the developed model is extremely simple, the obtained results of calculations, based on this model, show excellent agreement with those obtained by the above-mentioned models specially that one adopted by UNSCEAR. (authors)
Calculating patient specific doses in X-ray diagnostics and from radiopharmaceuticals
International Nuclear Information System (INIS)
Lampinen, J.
2000-01-01
The risk associated with exposure to ionising radiation is dependent on the characteristics of the exposed individual. The size and structure of the individual influences the absorbed dose distribution in the organs. Traditional methods used to calculate the patient organ doses are based on standardised calculation phantoms, which neglect the variance of the patient size or even sex. When estimating the radiation dose of an individual patient, patient specific calculation methods must be used. Methods for patient specific dosimetry in the fields of X-ray diagnostics and diagnostic and therapeutic use of radiopharmaceuticals were proposed in this thesis. A computer program, ODS-60, for calculating organ doses from diagnostic X-ray exposures was presented. The calculation is done in a patient specific phantom with depth dose and profile algorithms fitted to Monte Carlo simulation data from a previous study. Improvements to the version reported earlier were introduced, e.g. bone attenuation was implemented. The applicability of the program to determine patient doses from complex X-ray examinations (barium enema examination) was studied. The conversion equations derived for female and male patients as a function of patient weight gave the smallest deviation from the actual patient doses when compared to previous studies. Another computer program, Intdose, was presented for calculation of the dose distribution from radiopharmaceuticals. The calculation is based on convolution of an isotope specific point dose kernel with activity distribution, obtained from single photon emission computed tomography (SPECT) images. Anatomical information is taken from magnetic resonance (MR) or computed tomography (CT) images. According to a phantom study, Intdose agreed within 3 % with measurements. For volunteers administered diagnostic radiopharmaceuticals, the results given by Intdose were found to agree with traditional methods in cases of medium sized patients. For patients
SU-E-T-481: In Vivo and Post Mortem Animal Irradiation: Measured Vs. Calculated Doses
Energy Technology Data Exchange (ETDEWEB)
Heintz, P [Univ New Mexico Radiology Dept., Albuquerque, NM (United States); Heintz, B [Texas Oncology, PA, Southlake, TX (United States); Sandoval, D [University of New Mexico, Albuquerque, NM (United States); Weber, W; Melo, D; Guilmette, R [Lovelace Respiratory Research Institute, Albuquerque, NM (United States)
2015-06-15
Purpose: Computerized radiation therapy treatment planning is performed on almost all patients today. However it is seldom used for laboratory irradiations. The first objective is to assess whether modern radiation therapy treatment planning (RTP) systems accurately predict the subject dose by comparing in vivo and decedent dose measurements to calculated doses. The other objective is determine the importance of using a RTP system for laboratory irradiations. Methods: 5 MOSFET radiation dosimeters were placed enterically in each subject (2 sedated Rhesus Macaques) to measure the absorbed dose at 5 levels (carina, lung, heart, liver and rectum) during whole body irradiation. The subjects were treated with large opposed lateral fields and extended distances to cover the entire subject using a Varian 600C linac. CT simulation was performed ante-mortem (AM) and post-mortem (PM). To compare AM and PM doses, calculation points were placed at the location of each dosimeter in the treatment plan. The measured results were compared to the results using Varian Eclipse and Prowess Panther RTP systems. Results: The Varian and Prowess treatment planning system agreed to within in +1.5% for both subjects. However there were significant differences between the measured and calculated doses. For both animals the calculated central axis dose was higher than prescribed by 3–5%. This was caused in part by inaccurate measurement of animal thickness at the time of irradiation. For one subject the doses ranged from 4% to 7% high and the other subject the doses ranged 7% to 14% high when compared to the RTP doses. Conclusions: Our results suggest that using proper CT RTP system can more accurately deliver the prescribed dose to laboratory subjects. It also shows that there is significant dose variation in such subjects when inhomogeneities are not considered in the planning process.
THIDA: code system for calculation of the exposure dose rate around a fusion device
International Nuclear Information System (INIS)
Iida, Hiromasa; Igarashi, Masahito.
1978-12-01
A code system THIDA has been developed for calculation of the exposure dose rates around a fusion device. It consists of the following: one- and two-dimensional discrete ordinate transport codes; induced activity calculation code; activation chain, activation cross section, radionuclide gamma-ray energy/intensity and gamma-ray group constant files; and gamma ray flux to exposure dose rate conversion coefficients. (author)
Calculations of received dose for different points in the enrichment uranium oxide warehouse at 4%
International Nuclear Information System (INIS)
Alonso V, G.
1990-06-01
In order to verifying that the received dose so much inside as outside of the warehouse of enriched uranium dioxide to 4% it doesn't represent risk to the personnel, the modelling of this and the corresponding calculations for the extreme case of dose at contact are made. (Author)
Monte Carlo calculation of received dose from ingestion and inhalation of natural uranium
International Nuclear Information System (INIS)
Trobok, M.; Zupunski, Lj.; Spasic-Jokic, V.; Gordanic, V.; Sovilj, P.
2009-01-01
For the purpose of this study eighty samples are taken from the area Bela Crkva and Vrsac. The activity of radionuclide in the soil is determined by gamma- ray spectrometry. Monte Carlo method is used to calculate effective dose received by population resulting from the inhalation and ingestion of natural uranium. The estimated doses were compared with the legally prescribed levels. (author) [sr
Energy Technology Data Exchange (ETDEWEB)
Napier, Bruce A.; Eslinger, Paul W.; Tolstykh, Evgenia I.; Vorobiova, Marina I.; Tokareva, Elena E.; Akhramenko, Boris N.; Krivoschapov, Victor A.; Degteva, Marina O.
2017-11-01
Time-dependent thyroid doses were reconstructed for Techa River Cohort members living near the Mayak production facilities from 131I released to the atmosphere for all relevant exposure pathways. The calculational approach uses four general steps: 1) construct estimates of releases of 131I to the air from production facilities; 2) model the transport of 131I in the air and subsequent deposition on the ground and vegetation; 3) model the accumulation of 131I in soil, water, and food products (environmental media); and 4) calculate individual doses by matching appropriate lifestyle and consumption data for the individual to concentrations of 131I in environmental media. The dose calculations are implemented in a Monte Carlo framework that produces best estimates and confidence intervals of dose time-histories. The 131I contribution was 75-99% of the thyroid dose. The mean total thyroid dose for cohort members was 193 mGy and the median was 53 mGy. Thyroid doses for about 3% of cohort members were larger than 1 Gy. About 7% of children born in 1940-1950 had doses larger than 1 Gy. The uncertainty in the 131I dose estimates is low enough for this approach to be used in regional epidemiological studies.
EFFDOS - a FORTRAN-77-code for the calculation of the effective dose equivalent
International Nuclear Information System (INIS)
Baer, M.; Honcu, S.; Huebschmann, W.
1984-01-01
The FORTRAN-77-code EFFDOS calculates the effective dose equivalent according to ICRP 26 due to the longterm emission of radionuclides into the atmosphere for the following exposure pathways: inhalation, ingestion, γ-ground irradiation (γ-irradiation by radionuclides deposited on the ground) and β- or γ-submersion (irradiation by the passing radioactive cloud). For calculating the effective dose equivalent at a single spot it is necessary to put in the diffusion factor and - if need be - the washout factor; otherwise EFFDOS calculates the input data for the computer codes ISOLA III and WOLGA-1, which then are enabled to compute the atmospheric diffusion, ground deposition and local dose equivalent distribution for the requested exposure pathway. Atmospheric diffusion, deposition and radionuclide transfer are calculated according to the ''Allgemeine Berechnungsgrundlage ....'' recommended by the German Fed. Ministry of Interior. A sample calculated is added. (orig.) [de
Target dose study of effects of changes in the AAA calculation resolution on lung SABR plan
International Nuclear Information System (INIS)
Kim, Dae Il; Son, Sang Jun; Ahn, Bum Seok; Jung, Chi Hoon; Yoo, Suk Hyun
2014-01-01
Changing the calculation grid of AAA in Lung SABR plan and to analyze the changes in target dose, and investigated the effects associated with it, and considered a suitable method of application. 4D CT image that was used to plan all been taken with Brilliance Big Bore CT (Philips, Netherlands) and in Lung SABR plan(Eclipse TM ver10.0.42, Varian, the USA), use anisotropic analytic algorithm(AAA, ver.10, Varian Medical Systems, Palo Alto, CA, USA) and, was calculated by the calculation grid 1.0, 3.0, 5.0 mm in each Lung SABR plan. Lung SABR plan of 10 cases are using each of 1.0 mm, 3.0 mm, 5.0 mm calculation grid, and in case of use a 1.0 mm calculation grid V98 of the prescribed dose is about 99.5%±1.5%, Dmin of the prescribed dose is about 92.5±1.5% and Homogeneity Index(HI) is 1.0489±0.0025. In the case of use a 3.0 mm calculation grid V98 dose of the prescribed dose is about 90±4.5% , Dmin of the prescribed dose is about 87.5±3% and HI is about 1.07±1. In the case of use a 5.0 mm calculation grid V98 dose of the prescribed dose is about 63±15%, Dmin of the prescribed dose is about 83±4% and HI is about 1.13±0.2, respectively. The calculation grid of 1.0 mm is better improves the accuracy of dose calculation than using 3.0 mm and 5.mm, although calculation times increase in the case of smaller PTV relatively. As lung, spread relatively large and low density and small PTV, it is considered and good to use a calculation grid of 1.0 mm
Accuracy of internal dose calculations with special consideration of radiopharmaceutical biokinetics
International Nuclear Information System (INIS)
Roedler, H.D.
1981-01-01
The individual steps of internal dose calculation, including the models and data used, as well as error considerations, are analysed following a short synopsis on the formalism of absorbed dose calculation. The mean dose in a target tissue depends on the administered activity, the residence time of the activity in the source tissues and the mean absorbed dose in the target tissue per transformation in a source tissue. Usually, a standard dosage is applied in radionuclide studies except in children. Actually administered and nomial activities generally differ by less than 10%. For the purpose of internal dose calculation, the biokinetics of a radiopharmaceutical are reflected in the residence times for the individual source tissues. The methods and the evaluation of measurements of biodistribution and retention data are discussed. The extrapolation of animal data to man is treated in some detail, including a survey of the methods used, as well as an attempt for validating these methods. None of these seem to yield more convincing results than the direct transfer of the residence times from animal to man, at least for the two radiopharmaceuticals discussed. The minimum period of measurement to derive residence times for the purpose of dose calculation has been determined as about one physical half-time. Some problems of the dose per transformation to a phantom are presented, including the age- or size-dependence of the internal dose. Organ doses to the phantom, calculated from different apparently reliable sets of biokinetic data, are generally compatible within a factor of 2 to 3, and somatically effective doses are generally compatible within a factor of less than 2
Sensitivity of NTCP parameter values against a change of dose calculation algorithm
International Nuclear Information System (INIS)
Brink, Carsten; Berg, Martin; Nielsen, Morten
2007-01-01
Optimization of radiation treatment planning requires estimations of the normal tissue complication probability (NTCP). A number of models exist that estimate NTCP from a calculated dose distribution. Since different dose calculation algorithms use different approximations the dose distributions predicted for a given treatment will in general depend on the algorithm. The purpose of this work is to test whether the optimal NTCP parameter values change significantly when the dose calculation algorithm is changed. The treatment plans for 17 breast cancer patients have retrospectively been recalculated with a collapsed cone algorithm (CC) to compare the NTCP estimates for radiation pneumonitis with those obtained from the clinically used pencil beam algorithm (PB). For the PB calculations the NTCP parameters were taken from previously published values for three different models. For the CC calculations the parameters were fitted to give the same NTCP as for the PB calculations. This paper demonstrates that significant shifts of the NTCP parameter values are observed for three models, comparable in magnitude to the uncertainties of the published parameter values. Thus, it is important to quote the applied dose calculation algorithm when reporting estimates of NTCP parameters in order to ensure correct use of the models
International Nuclear Information System (INIS)
Andersson, Martin; Ryufuku, Susumu; Yasuda, Hiroshi
2011-01-01
Pilots, flight attendants, and passengers aboard jet aircrafts are subjected to higher cosmic radiation levels at high altitude than on the ground. Additional dose, received during flight is called 'aviation route dose'. Addressing the needs for precise and easy determination of aviation route doses (Sv), the authors have developed a new application 'JISCARD GUI' with a graphical user interface which provides dose rate (Sv/h) distribution along a flight route and aviation route dose. The graphical interface made with Adobe Flash provide functions to select airports on dynamic map or to search by airport/city names, and to report resulting aviation route doses and graphs of dose rate change through a flight. Dose rate data at several cut off rigidity, Rc and force field potential, FFP were calculated in advance using a PHITS-based analytical model and stored in the server as matrix data. Upon user's request of departure/arrival airports and flight date, interpolation using matrix data substantiates derivation of dose rate distribution in a simple and quick manner with sufficient accuracy. Precision of the dose calculation was verified by comparison with JISCARD EX (MS-Excel version) released in September 2008. This advanced application will be open to public through the website of the National Institute of Radiological Sciences in the near future. (author)
Dose rates from a C-14 source using extrapolation chamber and MC calculations
International Nuclear Information System (INIS)
Borg, J.
1996-05-01
The extrapolation chamber technique and the Monte Carlo (MC) calculation technique based on the EGS4 system have been studied for application for determination of dose rates in a low-energy β radiation field e.g., that from a 14 C source. The extrapolation chamber measurement method is the basic method for determination of dose rates in β radiation fields. Applying a number of correction factors and the stopping power ratio, tissue to air, the measured dose rate in an air volume surrounded by tissue equivalent material is converted into dose to tissue. Various details of the extrapolation chamber measurement method and evaluation procedure have been studied and further developed, and a complete procedure for the experimental determination of dose rates from a 14 C source is presented. A number of correction factors and other parameters used in the evaluation procedure for the measured data have been obtained by MC calculations. The whole extrapolation chamber measurement procedure was simulated using the MC method. The measured dose rates showed an increasing deviation from the MC calculated dose rates as the absorber thickness increased. This indicates that the EGS4 code may have some limitations for transport of very low-energy electrons. i.e., electrons with estimated energies less than 10 - 20 keV. MC calculations of dose to tissue were performed using two models: a cylindrical tissue phantom and a computer model of the extrapolation chamber. The dose to tissue in the extrapolation chamber model showed an additional buildup dose compared to the dose in the tissue model. (au) 10 tabs., 11 ills., 18 refs
The impact of dose calculation algorithms on partial and whole breast radiation treatment plans
International Nuclear Information System (INIS)
Basran, Parminder S; Zavgorodni, Sergei; Berrang, Tanya; Olivotto, Ivo A; Beckham, Wayne
2010-01-01
This paper compares the calculated dose to target and normal tissues when using pencil beam (PBC), superposition/convolution (AAA) and Monte Carlo (MC) algorithms for whole breast (WBI) and accelerated partial breast irradiation (APBI) treatment plans. Plans for 10 patients who met all dosimetry constraints on a prospective APBI protocol when using PBC calculations were recomputed with AAA and MC, keeping the monitor units and beam angles fixed. Similar calculations were performed for WBI plans on the same patients. Doses to target and normal tissue volumes were tested for significance using the paired Student's t-test. For WBI plans the average dose to target volumes when using PBC calculations was not significantly different than AAA calculations, the average PBC dose to the ipsilateral breast was 10.5% higher than the AAA calculations and the average MC dose to the ipsilateral breast was 11.8% lower than the PBC calculations. For ABPI plans there were no differences in dose to the planning target volume, ipsilateral breast, heart, ipsilateral lung, or contra-lateral lung. Although not significant, the maximum PBC dose to the contra-lateral breast was 1.9% higher than AAA and the PBC dose to the clinical target volume was 2.1% higher than AAA. When WBI technique is switched to APBI, there was significant reduction in dose to the ipsilateral breast when using PBC, a significant reduction in dose to the ipsilateral lung when using AAA, and a significant reduction in dose to the ipsilateral breast and lung and contra-lateral lung when using MC. There is very good agreement between PBC, AAA and MC for all target and most normal tissues when treating with APBI and WBI and most of the differences in doses to target and normal tissues are not clinically significant. However, a commonly used dosimetry constraint, as recommended by the ASTRO consensus document for APBI, that no point in the contra-lateral breast volume should receive >3% of the prescribed dose needs
A clinical study of lung cancer dose calculation accuracy with Monte Carlo simulation.
Zhao, Yanqun; Qi, Guohai; Yin, Gang; Wang, Xianliang; Wang, Pei; Li, Jian; Xiao, Mingyong; Li, Jie; Kang, Shengwei; Liao, Xiongfei
2014-12-16
The accuracy of dose calculation is crucial to the quality of treatment planning and, consequently, to the dose delivered to patients undergoing radiation therapy. Current general calculation algorithms such as Pencil Beam Convolution (PBC) and Collapsed Cone Convolution (CCC) have shortcomings in regard to severe inhomogeneities, particularly in those regions where charged particle equilibrium does not hold. The aim of this study was to evaluate the accuracy of the PBC and CCC algorithms in lung cancer radiotherapy using Monte Carlo (MC) technology. Four treatment plans were designed using Oncentra Masterplan TPS for each patient. Two intensity-modulated radiation therapy (IMRT) plans were developed using the PBC and CCC algorithms, and two three-dimensional conformal therapy (3DCRT) plans were developed using the PBC and CCC algorithms. The DICOM-RT files of the treatment plans were exported to the Monte Carlo system to recalculate. The dose distributions of GTV, PTV and ipsilateral lung calculated by the TPS and MC were compared. For 3DCRT and IMRT plans, the mean dose differences for GTV between the CCC and MC increased with decreasing of the GTV volume. For IMRT, the mean dose differences were found to be higher than that of 3DCRT. The CCC algorithm overestimated the GTV mean dose by approximately 3% for IMRT. For 3DCRT plans, when the volume of the GTV was greater than 100 cm(3), the mean doses calculated by CCC and MC almost have no difference. PBC shows large deviations from the MC algorithm. For the dose to the ipsilateral lung, the CCC algorithm overestimated the dose to the entire lung, and the PBC algorithm overestimated V20 but underestimated V5; the difference in V10 was not statistically significant. PBC substantially overestimates the dose to the tumour, but the CCC is similar to the MC simulation. It is recommended that the treatment plans for lung cancer be developed using an advanced dose calculation algorithm other than PBC. MC can accurately
Independent procedure of checking dose calculations using an independent calculus algorithm
International Nuclear Information System (INIS)
Perez Rozos, A.; Jerez Sainz, I.; Carrasco Rodriguez, J. L.
2006-01-01
In radiotherapy it is recommended the use of an independent procedure of checking dose calculations, in order to verify the main treatment planning system and double check every patient dosimetry. In this work we present and automatic spreadsheet that import data from planning system using IMPAC/RTP format and verify monitor unit calculation using an independent calculus algorithm. Additionally, it perform a personalized analysis of dose volume histograms and several radiobiological parameters like TCP and NTCP. Finally, the application automatically generate a clinical dosimetry report for every patient, including treatment fields, fractionation, independent check results, dose volume analysis, and first day forms. (Author)
International Nuclear Information System (INIS)
Strenge, D.L.; Watson, E.C.; Droppo, J.G.
1976-06-01
The development of technological bases for siting nuclear fuel cycle facilities requires calculational models and computer codes for the evaluation of risks and the assessment of environmental impact of radioactive effluents. A literature search and review of available computer programs revealed that no one program was capable of performing all of the great variety of calculations (i.e., external dose, internal dose, population dose, chronic release, accidental release, etc.). Available literature on existing computer programs has been reviewed and a description of each program reviewed is given
Analysis of Radiation Treatment Planning by Dose Calculation and Optimization Algorithm
Energy Technology Data Exchange (ETDEWEB)
Kim, Dae Sup; Yoon, In Ha; Lee, Woo Seok; Baek, Geum Mun [Dept. of Radiation Oncology, Asan Medical Center, Seoul (Korea, Republic of)
2012-09-15
Analyze the Effectiveness of Radiation Treatment Planning by dose calculation and optimization algorithm, apply consideration of actual treatment planning, and then suggest the best way to treatment planning protocol. The treatment planning system use Eclipse 10.0. (Varian, USA). PBC (Pencil Beam Convolution) and AAA (Anisotropic Analytical Algorithm) Apply to Dose calculation, DVO (Dose Volume Optimizer 10.0.28) used for optimized algorithm of Intensity Modulated Radiation Therapy (IMRT), PRO II (Progressive Resolution Optimizer V 8.9.17) and PRO III (Progressive Resolution Optimizer V 10.0.28) used for optimized algorithm of VAMT. A phantom for experiment virtually created at treatment planning system, 30x30x30 cm sized, homogeneous density (HU: 0) and heterogeneous density that inserted air assumed material (HU: -1,000). Apply to clinical treatment planning on the basis of general treatment planning feature analyzed with Phantom planning. In homogeneous density phantom, PBC and AAA show 65.2% PDD (6 MV, 10 cm) both, In heterogeneous density phantom, also show similar PDD value before meet with low density material, but they show different dose curve in air territory, PDD 10 cm showed 75%, 73% each after penetrate phantom. 3D treatment plan in same MU, AAA treatment planning shows low dose at Lung included area. 2D POP treatment plan with 15 MV of cervical vertebral region include trachea and lung area, Conformity Index (ICRU 62) is 0.95 in PBC calculation and 0.93 in AAA. DVO DVH and Dose calculation DVH are showed equal value in IMRT treatment plan. But AAA calculation shows lack of dose compared with DVO result which is satisfactory condition. Optimizing VMAT treatment plans using PRO II obtained results were satisfactory, but lower density area showed lack of dose in dose calculations. PRO III, but optimizing the dose calculation results were similar with optimized the same conditions once more. In this study, do not judge the rightness of the dose
Energy Technology Data Exchange (ETDEWEB)
Strenge, D.L.; Watson, E.C.; Droppo, J.G.
1976-06-01
The development of technological bases for siting nuclear fuel cycle facilities requires calculational models and computer codes for the evaluation of risks and the assessment of environmental impact of radioactive effluents. A literature search and review of available computer programs revealed that no one program was capable of performing all of the great variety of calculations (i.e., external dose, internal dose, population dose, chronic release, accidental release, etc.). Available literature on existing computer programs has been reviewed and a description of each program reviewed is given.
Dose calculation for 40K ingestion in samples of beans using spectrometry and MCNP
International Nuclear Information System (INIS)
Garcez, R.W.D.; Lopes, J.M.; Silva, A.X.; Domingues, A.M.; Lima, M.A.F.
2014-01-01
A method based on gamma spectroscopy and on the use of voxel phantoms to calculate dose due to ingestion of 40 K contained in bean samples are presented in this work. To quantify the activity of radionuclide, HPGe detector was used and the data entered in the input file of MCNP code. The highest value of equivalent dose was 7.83 μSv.y -1 in the stomach for white beans, whose activity 452.4 Bq.Kg -1 was the highest of the five analyzed. The tool proved to be appropriate when you want to calculate the dose in organs due to ingestion of food. (author)
Analysis of Radiation Treatment Planning by Dose Calculation and Optimization Algorithm
International Nuclear Information System (INIS)
Kim, Dae Sup; Yoon, In Ha; Lee, Woo Seok; Baek, Geum Mun
2012-01-01
Analyze the Effectiveness of Radiation Treatment Planning by dose calculation and optimization algorithm, apply consideration of actual treatment planning, and then suggest the best way to treatment planning protocol. The treatment planning system use Eclipse 10.0. (Varian, USA). PBC (Pencil Beam Convolution) and AAA (Anisotropic Analytical Algorithm) Apply to Dose calculation, DVO (Dose Volume Optimizer 10.0.28) used for optimized algorithm of Intensity Modulated Radiation Therapy (IMRT), PRO II (Progressive Resolution Optimizer V 8.9.17) and PRO III (Progressive Resolution Optimizer V 10.0.28) used for optimized algorithm of VAMT. A phantom for experiment virtually created at treatment planning system, 30x30x30 cm sized, homogeneous density (HU: 0) and heterogeneous density that inserted air assumed material (HU: -1,000). Apply to clinical treatment planning on the basis of general treatment planning feature analyzed with Phantom planning. In homogeneous density phantom, PBC and AAA show 65.2% PDD (6 MV, 10 cm) both, In heterogeneous density phantom, also show similar PDD value before meet with low density material, but they show different dose curve in air territory, PDD 10 cm showed 75%, 73% each after penetrate phantom. 3D treatment plan in same MU, AAA treatment planning shows low dose at Lung included area. 2D POP treatment plan with 15 MV of cervical vertebral region include trachea and lung area, Conformity Index (ICRU 62) is 0.95 in PBC calculation and 0.93 in AAA. DVO DVH and Dose calculation DVH are showed equal value in IMRT treatment plan. But AAA calculation shows lack of dose compared with DVO result which is satisfactory condition. Optimizing VMAT treatment plans using PRO II obtained results were satisfactory, but lower density area showed lack of dose in dose calculations. PRO III, but optimizing the dose calculation results were similar with optimized the same conditions once more. In this study, do not judge the rightness of the dose
TH-A-19A-09: Towards Sub-Second Proton Dose Calculation On GPU
Energy Technology Data Exchange (ETDEWEB)
Silva, J da [University of Cambridge, Cambridge, Cambridgeshire (United Kingdom)
2014-06-15
Purpose: To achieve sub-second dose calculation for clinically relevant proton therapy treatment plans. Rapid dose calculation is a key component of adaptive radiotherapy, necessary to take advantage of the better dose conformity offered by hadron therapy. Methods: To speed up proton dose calculation, the pencil beam algorithm (PBA; clinical standard) was parallelised and implemented to run on a graphics processing unit (GPU). The implementation constitutes the first PBA to run all steps on GPU, and each part of the algorithm was carefully adapted for efficiency. Monte Carlo (MC) simulations obtained using Fluka of individual beams of energies representative of the clinical range impinging on simple geometries were used to tune the PBA. For benchmarking, a typical skull base case with a spot scanning plan consisting of a total of 8872 spots divided between two beam directions of 49 energy layers each was provided by CNAO (Pavia, Italy). The calculations were carried out on an Nvidia Geforce GTX680 desktop GPU with 1536 cores running at 1006 MHz. Results: The PBA reproduced within ±3% of maximum dose results obtained from MC simulations for a range of pencil beams impinging on a water tank. Additional analysis of more complex slab geometries is currently under way to fine-tune the algorithm. Full calculation of the clinical test case took 0.9 seconds in total, with the majority of the time spent in the kernel superposition step. Conclusion: The PBA lends itself well to implementation on many-core systems such as GPUs. Using the presented implementation and current hardware, sub-second dose calculation for a clinical proton therapy plan was achieved, opening the door for adaptive treatment. The successful parallelisation of all steps of the calculation indicates that further speedups can be expected with new hardware, brightening the prospects for real-time dose calculation. This work was funded by ENTERVISION, European Commission FP7 grant 264552.
TH-A-19A-09: Towards Sub-Second Proton Dose Calculation On GPU
International Nuclear Information System (INIS)
Silva, J da
2014-01-01
Purpose: To achieve sub-second dose calculation for clinically relevant proton therapy treatment plans. Rapid dose calculation is a key component of adaptive radiotherapy, necessary to take advantage of the better dose conformity offered by hadron therapy. Methods: To speed up proton dose calculation, the pencil beam algorithm (PBA; clinical standard) was parallelised and implemented to run on a graphics processing unit (GPU). The implementation constitutes the first PBA to run all steps on GPU, and each part of the algorithm was carefully adapted for efficiency. Monte Carlo (MC) simulations obtained using Fluka of individual beams of energies representative of the clinical range impinging on simple geometries were used to tune the PBA. For benchmarking, a typical skull base case with a spot scanning plan consisting of a total of 8872 spots divided between two beam directions of 49 energy layers each was provided by CNAO (Pavia, Italy). The calculations were carried out on an Nvidia Geforce GTX680 desktop GPU with 1536 cores running at 1006 MHz. Results: The PBA reproduced within ±3% of maximum dose results obtained from MC simulations for a range of pencil beams impinging on a water tank. Additional analysis of more complex slab geometries is currently under way to fine-tune the algorithm. Full calculation of the clinical test case took 0.9 seconds in total, with the majority of the time spent in the kernel superposition step. Conclusion: The PBA lends itself well to implementation on many-core systems such as GPUs. Using the presented implementation and current hardware, sub-second dose calculation for a clinical proton therapy plan was achieved, opening the door for adaptive treatment. The successful parallelisation of all steps of the calculation indicates that further speedups can be expected with new hardware, brightening the prospects for real-time dose calculation. This work was funded by ENTERVISION, European Commission FP7 grant 264552
Energy Technology Data Exchange (ETDEWEB)
Chibani, Omar, E-mail: omar.chibani@fccc.edu; C-M Ma, Charlie [Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)
2014-05-15
Purpose: To present a new accelerated Monte Carlo code for CT-based dose calculations in high dose rate (HDR) brachytherapy. The new code (HDRMC) accounts for both tissue and nontissue heterogeneities (applicator and contrast medium). Methods: HDRMC uses a fast ray-tracing technique and detailed physics algorithms to transport photons through a 3D mesh of voxels representing the patient anatomy with applicator and contrast medium included. A precalculated phase space file for the{sup 192}Ir source is used as source term. HDRM is calibrated to calculated absolute dose for real plans. A postprocessing technique is used to include the exact density and composition of nontissue heterogeneities in the 3D phantom. Dwell positions and angular orientations of the source are reconstructed using data from the treatment planning system (TPS). Structure contours are also imported from the TPS to recalculate dose-volume histograms. Results: HDRMC was first benchmarked against the MCNP5 code for a single source in homogenous water and for a loaded gynecologic applicator in water. The accuracy of the voxel-based applicator model used in HDRMC was also verified by comparing 3D dose distributions and dose-volume parameters obtained using 1-mm{sup 3} versus 2-mm{sup 3} phantom resolutions. HDRMC can calculate the 3D dose distribution for a typical HDR cervix case with 2-mm resolution in 5 min on a single CPU. Examples of heterogeneity effects for two clinical cases (cervix and esophagus) were demonstrated using HDRMC. The neglect of tissue heterogeneity for the esophageal case leads to the overestimate of CTV D90, CTV D100, and spinal cord maximum dose by 3.2%, 3.9%, and 3.6%, respectively. Conclusions: A fast Monte Carlo code for CT-based dose calculations which does not require a prebuilt applicator model is developed for those HDR brachytherapy treatments that use CT-compatible applicators. Tissue and nontissue heterogeneities should be taken into account in modern HDR
Real-time dose calculation and visualization for the proton therapy of ocular tumours
Energy Technology Data Exchange (ETDEWEB)
Pfeiffer, Karsten [Medizinische Physik, Deutsches Krebsforschungszentrum, INF 280, D-69120 Heidelberg (Germany). E-mail: k.pfeiffer at dkfz.de; Bendl, Rolf [Medizinische Physik, Deutsches Krebsforschungszentrum, INF 280, D-69120 Heidelberg (Germany). E-mail: r.bendl at dkfz.de
2001-03-01
A new real-time dose calculation and visualization was developed as part of the new 3D treatment planning tool OCTOPUS for proton therapy of ocular tumours within a national research project together with the Hahn-Meitner Institut Berlin. The implementation resolves the common separation between parameter definition, dose calculation and evaluation and allows a direct examination of the expected dose distribution while adjusting the treatment parameters. The new tool allows the therapist to move the desired dose distribution under visual control in 3D to the appropriate place. The visualization of the resulting dose distribution as a 3D surface model, on any 2D slice or on the surface of specified ocular structures is done automatically when adapting parameters during the planning process. In addition, approximate dose volume histograms may be calculated with little extra time. The dose distribution is calculated and visualized in 200 ms with an accuracy of 6% for the 3D isodose surfaces and 8% for other objects. This paper discusses the advantages and limitations of this new approach. (author)
GTV-based prescription in SBRT for lung lesions using advanced dose calculation algorithms
International Nuclear Information System (INIS)
Lacornerie, Thomas; Lisbona, Albert; Mirabel, Xavier; Lartigau, Eric; Reynaert, Nick
2014-01-01
The aim of current study was to investigate the way dose is prescribed to lung lesions during SBRT using advanced dose calculation algorithms that take into account electron transport (type B algorithms). As type A algorithms do not take into account secondary electron transport, they overestimate the dose to lung lesions. Type B algorithms are more accurate but still no consensus is reached regarding dose prescription. The positive clinical results obtained using type A algorithms should be used as a starting point. In current work a dose-calculation experiment is performed, presenting different prescription methods. Three cases with three different sizes of peripheral lung lesions were planned using three different treatment platforms. For each individual case 60 Gy to the PTV was prescribed using a type A algorithm and the dose distribution was recalculated using a type B algorithm in order to evaluate the impact of the secondary electron transport. Secondly, for each case a type B algorithm was used to prescribe 48 Gy to the PTV, and the resulting doses to the GTV were analyzed. Finally, prescriptions based on specific GTV dose volumes were evaluated. When using a type A algorithm to prescribe the same dose to the PTV, the differences regarding median GTV doses among platforms and cases were always less than 10% of the prescription dose. The prescription to the PTV based on type B algorithms, leads to a more important variability of the median GTV dose among cases and among platforms, (respectively 24%, and 28%). However, when 54 Gy was prescribed as median GTV dose, using a type B algorithm, the variability observed was minimal. Normalizing the prescription dose to the median GTV dose for lung lesions avoids variability among different cases and treatment platforms of SBRT when type B algorithms are used to calculate the dose. The combination of using a type A algorithm to optimize a homogeneous dose in the PTV and using a type B algorithm to prescribe the
International Nuclear Information System (INIS)
Quade, U.
1994-01-01
Neutron- und Gamma dose rate calculations were performed for the storage containers filled with plutonium nitrate of the MOX fabrication facility of Siemens. For the particle transport calculations the Monte Carlo Code MCNP 4.2 was used. The calculated results were compared with experimental dose rate measurements. It can be stated that the choice of the code system was appropriate since all aspects of the many facettes of the problem were well reproduced in the calculations. The position dependency as well as the influence of the shieldings, the reflections and the mutual influences of the sources were well described by the calculations for the gamma and for the neutron dose rates. However, good agreement with the experimental results on the gamma dose rates could only be reached when the lead shielding of the detector was integrated into the geometry modelling of the calculations. For some few cases of thick shieldings and soft gamma ray sources the statistics of the calculational results were not sufficient. In such cases more elaborate variance reduction methods must be applied in future calculations. Thus the MCNP code in connection with NGSRC has been proven as an effective tool for the solution of this type of problems. (orig./HP) [de
International Nuclear Information System (INIS)
Lindberg, C.
1984-12-01
Low-dose whole-body exposure of mice to less than 0.01 Gy causes a temporary inhibition of incorporation of thymidine into DNA of bone-marrow cells in vitro. This inhibition has its maximum at 4 hours after irradiation. The low-dose effect is due to the temporary inhibition of cellular thymidine kinase. This decrease in thymidine kinase activity involves only 35% of the entire cellular enzyme activity and, analogous to the depression of thymidine incorporation into the cells, is only seen in the presence of a physiological concentration of NaHCO 3 . The inhibition of TdR-kinase at very low doses should not be viewed as an expression of cell damage but might be part of a cellular protection mechanism different from known repair systems. (orig.) [de
Incorporating partial shining effects in proton pencil-beam dose calculation
International Nuclear Information System (INIS)
Li Yupeng; Zhang Xiaodong; Lii Mingfwu; Sahoo, Narayan; Zhu, Ron X; Gillin, Michael; Mohan, Radhe
2008-01-01
A range modulator wheel (RMW) is an essential component in passively scattered proton therapy. We have observed that a proton beam spot may shine on multiple steps of the RMW. Proton dose calculation algorithms normally do not consider the partial shining effect, and thus overestimate the dose at the proximal shoulder of spread-out Bragg peak (SOBP) compared with the measurement. If the SOBP is adjusted to better fit the plateau region, the entrance dose is likely to be underestimated. In this work, we developed an algorithm that can be used to model this effect and to allow for dose calculations that better fit the measured SOBP. First, a set of apparent modulator weights was calculated without considering partial shining. Next, protons spilled from the accelerator reaching the modulator wheel were simplified as a circular spot of uniform intensity. A weight-splitting process was then performed to generate a set of effective modulator weights with the partial shining effect incorporated. The SOBPs of eight options, which are used to label different combinations of proton-beam energy and scattering devices, were calculated with the generated effective weights. Our algorithm fitted the measured SOBP at the proximal and entrance regions much better than the ones without considering partial shining effect for all SOBPs of the eight options. In a prostate patient, we found that dose calculation without considering partial shining effect underestimated the femoral head and skin dose
SU-E-T-67: Clinical Implementation and Evaluation of the Acuros Dose Calculation Algorithm
International Nuclear Information System (INIS)
Yan, C; Combine, T; Dickens, K; Wynn, R; Pavord, D; Huq, M
2014-01-01
Purpose: The main aim of the current study is to present a detailed description of the implementation of the Acuros XB Dose Calculation Algorithm, and subsequently evaluate its clinical impacts by comparing it with AAA algorithm. Methods: The source models for both Acuros XB and AAA were configured by importing the same measured beam data into Eclipse treatment planning system. Both algorithms were evaluated by comparing calculated dose with measured dose on a homogeneous water phantom for field sizes ranging from 6cm × 6cm to 40cm × 40cm. Central axis and off-axis points with different depths were chosen for the comparison. Similarly, wedge fields with wedge angles from 15 to 60 degree were used. In addition, variable field sizes for a heterogeneous phantom were used to evaluate the Acuros algorithm. Finally, both Acuros and AAA were tested on VMAT patient plans for various sites. Does distributions and calculation time were compared. Results: On average, computation time is reduced by at least 50% by Acuros XB compared with AAA on single fields and VMAT plans. When used for open 6MV photon beams on homogeneous water phantom, both Acuros XB and AAA calculated doses were within 1% of measurement. For 23 MV photon beams, the calculated doses were within 1.5% of measured doses for Acuros XB and 2% for AAA. When heterogeneous phantom was used, Acuros XB also improved on accuracy. Conclusion: Compared with AAA, Acuros XB can improve accuracy while significantly reduce computation time for VMAT plans
An independent dose calculation algorithm for MLC-based stereotactic radiotherapy
International Nuclear Information System (INIS)
Lorenz, Friedlieb; Killoran, Joseph H.; Wenz, Frederik; Zygmanski, Piotr
2007-01-01
We have developed an algorithm to calculate dose in a homogeneous phantom for radiotherapy fields defined by multi-leaf collimator (MLC) for both static and dynamic MLC delivery. The algorithm was developed to supplement the dose algorithms of the commercial treatment planning systems (TPS). The motivation for this work is to provide an independent dose calculation primarily for quality assurance (QA) and secondarily for the development of static MLC field based inverse planning. The dose calculation utilizes a pencil-beam kernel. However, an explicit analytical integration results in a closed form for rectangular-shaped beamlets, defined by single leaf pairs. This approach reduces spatial integration to summation, and leads to a simple method of determination of model parameters. The total dose for any static or dynamic MLC field is obtained by summing over all individual rectangles from each segment which offers faster speed to calculate two-dimensional dose distributions at any depth in the phantom. Standard beam data used in the commissioning of the TPS was used as input data for the algorithm. The calculated results were compared with the TPS and measurements for static and dynamic MLC. The agreement was very good (<2.5%) for all tested cases except for very small static MLC sizes of 0.6 cmx0.6 cm (<6%) and some ion chamber measurements in a high gradient region (<4.4%). This finding enables us to use the algorithm for routine QA as well as for research developments
International Nuclear Information System (INIS)
Suleiman, O.H.
1989-01-01
A method was developed to quantitatively measure the upper gastrointestinal fluoroscopic examination in order to calculate organ doses. The dynamic examination was approximated with a set of discrete x-ray fields. Once the examination was segmented into discrete x-ray fields appropriate organ dose tables were generated using an existing computer program for organ dose calculations. This, along with knowledge of the radiation exposures associated with each of the fields, enabled the calculation of organ doses for the entire dynamic examination. The protocol involves videotaping the examination while fluoroscopic technique factors, tube current and tube potential, are simultaneously recorded on the audio tracks of the videotape. Subsequent analysis allows the dynamic examination to be segmented into a series of discrete x-ray fields uniquely defined by field size, projection, and anatomical region. The anatomical regions associated with the upper gastrointestinal examination were observed to be the upper, middle, and lower esophagus, the gastroesophageal junction, the stomach, and the duodenum
Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides
International Nuclear Information System (INIS)
Akabani, G.; Poston, J.W. Sr.
1992-01-01
At present, absorbed dose calculations for radionuclides in the human circulatory system use relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, Monte Carlo calculations were performed using the code Electron Gamma Shower (EGS4). Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessel sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was or cross fire between blood vessels was assumed. Results are useful in assessing the doses to blood and blood vessel walls for different nuclear medicine procedures
Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides
International Nuclear Information System (INIS)
Akabani, G.; Poston, J.W.
1991-05-01
At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Monte Carlo calculations were performed. Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessels sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was assumed nor cross fire between vessel was assumed. Results are useful in assessing the dose in blood and blood vessel walls for different nuclear medicine procedures. 6 refs., 6 figs., 5 tabs
Calculation of photon dose for Dalat research reactor in case of loss of reactor tank water
International Nuclear Information System (INIS)
Le Vinh Vinh; Huynh Ton Nghiem; Nguyen Kien Cuong
2007-01-01
Photon sources of actinides and fission products were estimated by ORIGEN2 code with the modified cross-section library for Dalat research reactor (DRR) using new cross-section generated by WIMS-ANL code. Photon sources of reactor tank water calculated from the experimental data. MCNP4C2 with available non-analog Monte Carlo model and ANSI/ANL-6.1.1-1977 flux-to-dose factors were used for dose estimation. The agreement between calculation results and those of measurements showed that the methods and models used to get photon sources and dose were acceptable. In case the reactor water totally leaks out from the reactor tank, the calculated dose is very high at the top of reactor tank while still low in control room. In the reactor hall, the operation staffs can access for emergency works but with time limits. (author)
Energy Technology Data Exchange (ETDEWEB)
Klüter, Sebastian, E-mail: sebastian.klueter@med.uni-heidelberg.de; Schubert, Kai; Lissner, Steffen; Sterzing, Florian; Oetzel, Dieter; Debus, Jürgen [Department of Radiation Oncology, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany, and Heidelberg Institute for Radiation Oncology (HIRO), Im Neuenheimer Feld 400, 69120 Heidelberg, Germany, and German Consortium for Translational Cancer Research (DKTK), Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Schlegel, Wolfgang [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Oelfke, Uwe [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom); Nill, Simeon [Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom)
2014-08-15
Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatment field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local
International Nuclear Information System (INIS)
Klüter, Sebastian; Schubert, Kai; Lissner, Steffen; Sterzing, Florian; Oetzel, Dieter; Debus, Jürgen; Schlegel, Wolfgang; Oelfke, Uwe; Nill, Simeon
2014-01-01
Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatment field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local
Calculation of radiation dose rates from a spent nuclear fuel shipping cask
International Nuclear Information System (INIS)
Chen, S.Y.; Yuan, Y.C.
1988-01-01
Radiation doses from a spent nuclear fuel cask are usually from various phases of operations during handling, shipping, and storage of the casks. Assessment of such doses requires knowledge of external radiation dose rates at various locations surrounding a cask. Under current practices, dose rates from gamma photons are usually estimated by means of point- or line-source approaches incorporating the conventional buildup factors. Although such simplified approaches may at times be easy to use, their accuracy has not been verified. For example, those simplified methods have not taken into account influencing factors such as the geometry of the cask and the presence of the ground surface, and the effects of these factors on the calculated dose rates are largely unknown. Moreover, similar empirical equations for buildup factors currently do not exist for neutrons. The objective of this study is to use a more accurate approach in calculating radiation dose rates for both neutrons and gamma photons from a spent fuel cask. The calculation utilizes the more sophisticated transport method and takes into account the geometry of the cask and the presence of the ground surface. The results of a detailed study of dose rates in the near field (within 20 meters) are presented and, for easy application, the cask centerline dose rates are fitted into empirical equations at cask centerline distances up to 2000 meters from the surface of the cask
Dose variations with varying calculation grid size in head and neck IMRT
Energy Technology Data Exchange (ETDEWEB)
Chung, Heeteak [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Fl 32611-8300 (United States); Jin, Hosang [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Fl 32611-8300 (United States); Palta, Jatinder [Department of Radiation Oncology, University of Florida, Gainesville, Fl 32610-0385 (United States); Suh, Tae-Suk [Department of Biomedical Engineering, Catholic University of Korea (Korea, Republic of); Kim, Siyong [Department of Radiation Oncology, University of Florida, Gainesville, Fl 32610-0385 (United States)
2006-10-07
Ever since the advent and development of treatment planning systems, the uncertainty associated with calculation grid size has been an issue. Even to this day, with highly sophisticated 3D conformal and intensity-modulated radiation therapy (IMRT) treatment planning systems (TPS), dose uncertainty due to grid size is still a concern. A phantom simulating head and neck treatment was prepared from two semi-cylindrical solid water slabs and a radiochromic film was inserted between the two slabs for measurement. Plans were generated for a 5400 cGy prescribed dose using Philips Pinnacle{sup 3} TPS for two targets, one shallow ({approx}0.5 cm depth) and one deep ({approx}6 cm depth). Calculation grid sizes of 1.5, 2, 3 and 4 mm were considered. Three clinical cases were also evaluated. The dose differences for the varying grid sizes (2 mm, 3 mm and 4 mm from 1.5 mm) in the phantom study were 126 cGy (2.3% of the 5400 cGy dose prescription), 248.2 cGy (4.6% of the 5400 cGy dose prescription) and 301.8 cGy (5.6% of the 5400 cGy dose prescription), respectively for the shallow target case. It was found that the dose could be varied to about 100 cGy (1.9% of the 5400 cGy dose prescription), 148.9 cGy (2.8% of the 5400 cGy dose prescription) and 202.9 cGy (3.8% of the 5400 cGy dose prescription) for 2 mm, 3 mm and 4 mm grid sizes, respectively, simply by shifting the calculation grid origin. Dose difference with a different range of the relative dose gradient was evaluated and we found that the relative dose difference increased with an increase in the range of the relative dose gradient. When comparing varying calculation grid sizes and measurements, the variation of the dose difference histogram was insignificant, but a local effect was observed in the dose difference map. Similar results were observed in the case of the deep target and the three clinical cases also showed results comparable to those from the phantom study.
Dose variations with varying calculation grid size in head and neck IMRT
International Nuclear Information System (INIS)
Chung, Heeteak; Jin, Hosang; Palta, Jatinder; Suh, Tae-Suk; Kim, Siyong
2006-01-01
Ever since the advent and development of treatment planning systems, the uncertainty associated with calculation grid size has been an issue. Even to this day, with highly sophisticated 3D conformal and intensity-modulated radiation therapy (IMRT) treatment planning systems (TPS), dose uncertainty due to grid size is still a concern. A phantom simulating head and neck treatment was prepared from two semi-cylindrical solid water slabs and a radiochromic film was inserted between the two slabs for measurement. Plans were generated for a 5400 cGy prescribed dose using Philips Pinnacle 3 TPS for two targets, one shallow (∼0.5 cm depth) and one deep (∼6 cm depth). Calculation grid sizes of 1.5, 2, 3 and 4 mm were considered. Three clinical cases were also evaluated. The dose differences for the varying grid sizes (2 mm, 3 mm and 4 mm from 1.5 mm) in the phantom study were 126 cGy (2.3% of the 5400 cGy dose prescription), 248.2 cGy (4.6% of the 5400 cGy dose prescription) and 301.8 cGy (5.6% of the 5400 cGy dose prescription), respectively for the shallow target case. It was found that the dose could be varied to about 100 cGy (1.9% of the 5400 cGy dose prescription), 148.9 cGy (2.8% of the 5400 cGy dose prescription) and 202.9 cGy (3.8% of the 5400 cGy dose prescription) for 2 mm, 3 mm and 4 mm grid sizes, respectively, simply by shifting the calculation grid origin. Dose difference with a different range of the relative dose gradient was evaluated and we found that the relative dose difference increased with an increase in the range of the relative dose gradient. When comparing varying calculation grid sizes and measurements, the variation of the dose difference histogram was insignificant, but a local effect was observed in the dose difference map. Similar results were observed in the case of the deep target and the three clinical cases also showed results comparable to those from the phantom study
Iliac crest tap; Sternal tap; Leukemia - bone marrow aspiration; Aplastic anemia - bone marrow aspiration; Myelodysplastic syndrome - bone marrow aspiration; Thrombocytopenia - bone marrow aspiration; Myelofibrosis - bone marrow aspiration
Molinelli, Silvia; Mairani, Andrea; Matsufuji, Naruhiro; Kanematsu, Nobuyuki; Inaniwa, Taku; Mirandola, Alfredo; Russo, Stefania; Mastella, Edoardo; Hasegawa, Azusa; Tsuji, Hiroshi; Yamada, Shigeru; Vischioni, Barbara; Vitolo, Viviana; Ferrari, Alfredo; Ciocca, Mario; Kamada, Tadashi; Tsujii, Hirohiko; Orecchia, Roberto; Fossati, Piero
2016-01-01
Background and purpose: In carbon ion radiotherapy (CIRT), the use of different relative biological effectiveness (RBE) models in the RBE-weighted dose $(D_{RBE})$ calculation can lead to deviations in the physical dose $(D_{phy})$ delivered to the patient. Our aim is to reduce target $D_{phy}$ deviations by converting prescription dose values. Material and methods: Planning data of patients treated at the National Institute of Radiological Sciences (NIRS) were collected, with prescribed doses per fraction ranging from 3.6 Gy (RBE) to 4.6 Gy (RBE), according to the Japanese semi-empirical model. The $D_{phy}$ was Monte Carlo (MC) re-calculated simulating the NIRS beamline. The local effect model (LEM)_I was then applied to estimate $D_{RBE}$. Target median $D_{RBE}$ ratios between MC + LEM_I and NIRS plans determined correction factors for the conversion of prescription doses. Plans were re-optimized in a LEM_I-based commercial system, prescribing the NIRS uncorrected and corrected $D_{RBE}$. Results: The MC ...
Fast pencil beam dose calculation for proton therapy using a double-Gaussian beam model
Directory of Open Access Journals (Sweden)
Joakim eda Silva
2015-12-01
Full Text Available The highly conformal dose distributions produced by scanned proton pencil beams are more sensitive to motion and anatomical changes than those produced by conventional radiotherapy. The ability to calculate the dose in real time as it is being delivered would enable, for example, online dose monitoring, and is therefore highly desirable. We have previously described an implementation of a pencil beam algorithm running on graphics processing units (GPUs intended specifically for online dose calculation. Here we present an extension to the dose calculation engine employing a double-Gaussian beam model to better account for the low-dose halo. To the best of our knowledge, it is the first such pencil beam algorithm for proton therapy running on a GPU. We employ two different parametrizations for the halo dose, one describing the distribution of secondary particles from nuclear interactions found in the literature and one relying on directly fitting the model to Monte Carlo simulations of pencil beams in water. Despite the large width of the halo contribution, we show how in either case the second Gaussian can be included whilst prolonging the calculation of the investigated plans by no more than 16%, or the calculation of the most time-consuming energy layers by about 25%. Further, the calculation time is relatively unaffected by the parametrization used, which suggests that these results should hold also for different systems. Finally, since the implementation is based on an algorithm employed by a commercial treatment planning system, it is expected that with adequate tuning, it should be able to reproduce the halo dose from a general beam line with sufficient accuracy.
International Nuclear Information System (INIS)
Corley, J.P.; Baker, D.A.; Hill, E.R.; Wendell, L.L.
1977-09-01
To simplify the calculation of potential long-distance environmental impacts, an overall average population exposure coefficient (P.E.C.) for the entire contiguous United States was calculated for releases to the atmosphere from Hanford facilities. The method, requiring machine computation, combines Bureau of Census population data by census enumeration district and an annual average atmospheric dilution factor (anti chi/Q') derived from 12-hourly gridded wind analyses provided by the NOAA's National Meteorological Center. A variable-trajectory puff-advection model was used to calculate an hourly anti chi/Q' for each grid square, assuming uniform hourly releases; seasonal and annual averages were then calculated. For Hanford, using 1970 census data, a P.E.C. of 2 x 10 -3 man-seconds per cubic meter was calculated. The P.E.C. is useful for both radioactive and nonradioactive releases. To calculate population doses for the entire contiguous United States, the P.E.C. is multiplied by the annual average release rate and then by the dose factor (rem/yr per Ci/m 3 ) for each radionuclide, and the dose contribution in man-rem is summed for all radionuclides. For multiple pathways, the P.E.C. is still useful, provided that doses from a unit release can be obtained from a set of atmospheric dose factors. The methodology is applicable to any point source, any set of population data by map grid coordinates, and any geographical area covered by equivalent meteorological data
International Nuclear Information System (INIS)
Karlberg, O.; Schwartz, H.; Forssen, B.-H.; Marklund, J.-E.
1979-01-01
UNIDOSE is a program system for calculating the consequences of a radioactive release to the atmosphere. The program is applicable for computation of dispersion in a rnage of 0 - 50 km from the release point. The Gaussion plume model is used for calculating the external dose from activity in the atmosphere, on the ground and the internal dose via inhalation. Radioactive decay, as well as growth and decay of daughter products are accounted for. The influence of dry deposition and wash-out are also considered. It is possible to treat time-dependent release-rates of 1 - 24 hours duration and constant release-rates for up to one year. The program system also contains routines for the calculation of collective dose and health effects. The system operates in a statistical manner. Many weather-situations, based on measured data, can be analysed and statistical properties, such as cumulative frequences, can be calculated. (author)
Monte Carlo Calculations of Dose to Medium and Dose to Water for Carbon Ion Beams in Various Media
DEFF Research Database (Denmark)
Herrmann, Rochus; Petersen, Jørgen B.B.; Jäkel, Oliver
treatment plans. Here, we quantisize the effect of dose to water vs. dose to medium for a series of typical target materials found in medical physics. 2 Material and Methods The Monte Carlo code FLUKA [Battistioni et al. 2007] is used to simulate the particle fluence spectrum in a series of target...... for water. This represents the case that our “detector” is an infinitesimal small non-perturbing entity made of water, where charged particle equilibrium can be assumed following the Bragg-Gray cavity theory. Dw and Dm are calculated for typical materials such as bone, brain, lung and soft-tissues using...
Evaluation of an electron Monte Carlo dose calculation algorithm for treatment planning.
Chamberland, Eve; Beaulieu, Luc; Lachance, Bernard
2015-05-08
The purpose of this study is to evaluate the accuracy of the electron Monte Carlo (eMC) dose calculation algorithm included in a commercial treatment planning system and compare its performance against an electron pencil beam algorithm. Several tests were performed to explore the system's behavior in simple geometries and in configurations encountered in clinical practice. The first series of tests were executed in a homogeneous water phantom, where experimental measurements and eMC-calculated dose distributions were compared for various combinations of energy and applicator. More specifically, we compared beam profiles and depth-dose curves at different source-to-surface distances (SSDs) and gantry angles, by using dose difference and distance to agreement. Also, we compared output factors, we studied the effects of algorithm input parameters, which are the random number generator seed, as well as the calculation grid size, and we performed a calculation time evaluation. Three different inhomogeneous solid phantoms were built, using high- and low-density materials inserts, to clinically simulate relevant heterogeneity conditions: a small air cylinder within a homogeneous phantom, a lung phantom, and a chest wall phantom. We also used an anthropomorphic phantom to perform comparison of eMC calculations to measurements. Finally, we proceeded with an evaluation of the eMC algorithm on a clinical case of nose cancer. In all mentioned cases, measurements, carried out by means of XV-2 films, radiographic films or EBT2 Gafchromic films. were used to compare eMC calculations with dose distributions obtained from an electron pencil beam algorithm. eMC calculations in the water phantom were accurate. Discrepancies for depth-dose curves and beam profiles were under 2.5% and 2 mm. Dose calculations with eMC for the small air cylinder and the lung phantom agreed within 2% and 4%, respectively. eMC calculations for the chest wall phantom and the anthropomorphic phantom also
Goncars, Valdis; Jakobsons, Eriks; Blums, Kristaps; Briede, Ieva; Patetko, Liene; Erglis, Kristaps; Erglis, Martins; Kalnberzs, Konstantins; Muiznieks, Indrikis; Erglis, Andrejs
2017-01-01
The aim of this study was to compare treatment methods of the knee joint degenerative osteoarthritis, using autologous bone marrow-derived mononuclear cells and hyaluronic acid injections and observe prevalence of adverse effects in both groups. A prospective randomized controlled clinical trial was carried out. The analysis of pain and changes in osteoarthritis symptoms after a single intra-articular bone marrow-derived mononuclear cell injection into the knee joint in the Kellgren-Lawrence stage II-III osteoarthritis during the 12-month period were performed. The results were compared with the control group treated routinely by hyaluronic acid injections therapy. A therapy group of patients (n=28) received single bone marrow-derived mononuclear cell intra-articular injections. A control group of patients (n=28) was treated with a total of three sodium hyaluronate intra-articular injections each one performed a week apart. The clinical results were obtained using the Knee Osteoarthritis Outcome Score (KOOS) and the Knee Society Score (KSS) before and 3, 6, and 12 months after injection. A statistically significant improvement was observed in the mononuclear cell group over the starting point in all scores. At the endpoint at month 12, the KOOS score improved significantly (Phyaluronic acid versus the bone marrow-derived mononuclear cells group at time points 6 and 12 months demonstrated a statistically significant (Phyaluronic acid group. In both groups serious adverse effects were not observed. The intra-articular injection of bone marrow-derived mononuclear cells is a safe manipulation with no side effects during the 12-month period. This treatment provides statistically significant clinical improvement between the starting point and 1, 3, 6, and 12 months after. When compared to hyaluronic acid treatment, better pain relief in the long-term period of mononuclear cell group was observed. Copyright © 2017 The Lithuanian University of Health Sciences. Production
Calculation of fast neutron dose in plastic-coated optical fibers
International Nuclear Information System (INIS)
Siebert, B.R.L.; Henschel, H.
1998-01-01
The dose of fast neutrons in optical fibers with hydrogen-containing coating materials is considerably increased by energetic recoil protons. Their contribution to the dose in a SiO 2 fiber core is calculated by the Monte Carlo method for different fiber geometries and a fiber optic cable. With 14 MeV neutrons the dose in a single fiber is increased by about 21%, whereas in fiber bundles the dose increase can reach about 170%. Maximum dose enhancement in fiber bundles (about 610%) occurs at neutron energies around 5.5 MeV. The dose increase caused by 14 MeV neutrons in the fiber of a typical laboratory cable is about 124%
The calculation of the surface dose in examinations following cardiac catheterization
International Nuclear Information System (INIS)
Ewen, K.
1995-01-01
It is inevitable in examinations requiring patient exposure to high doses that the investigators and medical assistants receive high wholebody doses on account of fray radiation and, occasionally, also high partial body doses (hands) on account of the useful beam range. A number of different circumstances are adding up to create this extreme situation. In this connection, a mathematical method for the calculation of the surface dose (cutaneous dose rate) is described that is based on sets of parameters commonly used in diagnostic radiology: Set I of parameters: Tube voltage - current strength of tube - distance between focus and skin; - set II of parameters: Incidence dose rate of image intensifier - distance between focus and skin -distance between image intensifier and plane of ray incidence (skin). (orig./VHE) [de
Postimplant Dosimetry Using a Monte Carlo Dose Calculation Engine: A New Clinical Standard
International Nuclear Information System (INIS)
Carrier, Jean-Francois; D'Amours, Michel; Verhaegen, Frank; Reniers, Brigitte; Martin, Andre-Guy; Vigneault, Eric; Beaulieu, Luc
2007-01-01
Purpose: To use the Monte Carlo (MC) method as a dose calculation engine for postimplant dosimetry. To compare the results with clinically approved data for a sample of 28 patients. Two effects not taken into account by the clinical calculation, interseed attenuation and tissue composition, are being specifically investigated. Methods and Materials: An automated MC program was developed. The dose distributions were calculated for the target volume and organs at risk (OAR) for 28 patients. Additional MC techniques were developed to focus specifically on the interseed attenuation and tissue effects. Results: For the clinical target volume (CTV) D 90 parameter, the mean difference between the clinical technique and the complete MC method is 10.7 Gy, with cases reaching up to 17 Gy. For all cases, the clinical technique overestimates the deposited dose in the CTV. This overestimation is mainly from a combination of two effects: the interseed attenuation (average, 6.8 Gy) and tissue composition (average, 4.1 Gy). The deposited dose in the OARs is also overestimated in the clinical calculation. Conclusions: The clinical technique systematically overestimates the deposited dose in the prostate and in the OARs. To reduce this systematic inaccuracy, the MC method should be considered in establishing a new standard for clinical postimplant dosimetry and dose-outcome studies in a near future
Energy Technology Data Exchange (ETDEWEB)
García-Garduño, O. A., E-mail: oagarciag@innn.edu.mx, E-mail: amanda.garcia.g@gmail.com [Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía, Mexico City 14269, México and Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, Legaria 694, México City 11500, México (Mexico); Rodríguez-Ponce, M. [Departamento de Biofísica, Instituto Nacional de Cancerología, Mexico City 14080, México (Mexico); Gamboa-deBuen, I. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510 (Mexico); Rodríguez-Villafuerte, M. [Instituto de Física, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510 (Mexico); Galván de la Cruz, O. O. [Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía, Mexico City 14269, México (Mexico); and others
2014-09-15
Purpose: To assess the impact of the detector used to commission small photon beams on the calculated dose distribution in stereotactic radiosurgery (SRS). Methods: In this study, six types of detectors were used to characterize small photon beams: three diodes [a silicon stereotactic field diode SFD, a silicon diode SRS, and a silicon diode E], an ionization chamber CC01, and two types of radiochromic film models EBT and EBT2. These detectors were used to characterize circular collimated beams that were generated by a Novalis linear accelerator. This study was conducted in two parts. First, the following dosimetric data, which are of particular interest in SRS, were compared for the different detectors: the total scatter factor (TSF), the tissue phantom ratios (TPRs), and the off-axis ratios (OARs). Second, the commissioned data sets were incorporated into the treatment planning system (TPS) to compare the calculated dose distributions and the dose volume histograms (DVHs) that were obtained using the different detectors. Results: The TSFs data measured by all of the detectors were in good agreement with each other within the respective statistical uncertainties: two exceptions, where the data were systematically below those obtained for the other detectors, were the CC01 results for all of the circular collimators and the EBT2 film results for circular collimators with diameters below 10.0 mm. The OAR results obtained for all of the detectors were in excellent agreement for all of the circular collimators. This observation was supported by the gamma-index test. The largest difference in the TPR data was found for the 4.0 mm circular collimator, followed by the 10.0 and 20.0 mm circular collimators. The results for the calculated dose distributions showed that all of the detectors passed the gamma-index test at 100% for the 3 mm/3% criteria. The aforementioned observation was true regardless of the size of the calculation grid for all of the circular collimators
International Nuclear Information System (INIS)
Morrison, Hali; Menon, Geetha; Sloboda, Ron
2016-01-01
Purpose: To investigate the accuracy of model-based dose calculations using a collapsed-cone algorithm for COMS eye plaques loaded with I-125 seeds. Methods: The Nucletron SelectSeed 130.002 I-125 seed and the 12 mm COMS eye plaque were incorporated into a research version of the Oncentra® Brachy v4.5 treatment planning system which uses the Advanced Collapsed-cone Engine (ACE) algorithm. Comparisons of TG-43 and high-accuracy ACE doses were performed for a single seed in a 30×30×30 cm 3 water box, as well as with one seed in the central slot of the 12 mm COMS eye plaque. The doses along the plaque central axis (CAX) were used to calculate the carrier correction factor, T(r), and were compared to tabulated and MCNP6 simulated doses for both the SelectSeed and IsoAid IAI-125A seeds. Results: The ACE calculated dose for the single seed in water was on average within 0.62 ± 2.2% of the TG-43 dose, with the largest differences occurring near the end-welds. The ratio of ACE to TG-43 calculated doses along the CAX (T(r)) of the 12 mm COMS plaque for the SelectSeed was on average within 3.0% of previously tabulated data, and within 2.9% of the MCNP6 simulated values. The IsoAid and SelectSeed T(r) values agreed within 0.3%. Conclusions: Initial comparisons show good agreement between ACE and MC doses for a single seed in a 12 mm COMS eye plaque; more complicated scenarios are being investigated to determine the accuracy of this calculation method.
Energy Technology Data Exchange (ETDEWEB)
Morrison, Hali; Menon, Geetha; Sloboda, Ron [Cross Cancer Institute, Edmonton, AB, and University of Alberta, Edmonton, AB, Cross Cancer Institute, Edmonton, AB, and University of Alberta, Edmonton, AB, Cross Cancer Institute, Edmonton, AB, and University of Alberta, Edmonton, AB (Canada)
2016-08-15
Purpose: To investigate the accuracy of model-based dose calculations using a collapsed-cone algorithm for COMS eye plaques loaded with I-125 seeds. Methods: The Nucletron SelectSeed 130.002 I-125 seed and the 12 mm COMS eye plaque were incorporated into a research version of the Oncentra® Brachy v4.5 treatment planning system which uses the Advanced Collapsed-cone Engine (ACE) algorithm. Comparisons of TG-43 and high-accuracy ACE doses were performed for a single seed in a 30×30×30 cm{sup 3} water box, as well as with one seed in the central slot of the 12 mm COMS eye plaque. The doses along the plaque central axis (CAX) were used to calculate the carrier correction factor, T(r), and were compared to tabulated and MCNP6 simulated doses for both the SelectSeed and IsoAid IAI-125A seeds. Results: The ACE calculated dose for the single seed in water was on average within 0.62 ± 2.2% of the TG-43 dose, with the largest differences occurring near the end-welds. The ratio of ACE to TG-43 calculated doses along the CAX (T(r)) of the 12 mm COMS plaque for the SelectSeed was on average within 3.0% of previously tabulated data, and within 2.9% of the MCNP6 simulated values. The IsoAid and SelectSeed T(r) values agreed within 0.3%. Conclusions: Initial comparisons show good agreement between ACE and MC doses for a single seed in a 12 mm COMS eye plaque; more complicated scenarios are being investigated to determine the accuracy of this calculation method.
Investigation of bulk electron densities for dose calculations on cone-beam CT images
International Nuclear Information System (INIS)
Lambert, J.; Parker, J.; Gupta, S.; Hatton, J.; Tang, C.; Capp, A.; Denham, J.W.; Wright, P.
2010-01-01
Full text: If cone-beam CT images are to be used for dose calculations, then the images must be able to provide accurate electron density information. Twelve patients underwent twice weekly cone-beam CT scans in addition to the planning CT scan. A standardised 5-field treatment plan was applied to 169 of the CBCT images. Doses were calculated using the original electron density values in the CBCT and with bulk electron densities applied. Bone was assigned a density of 288 HU, and all other tissue was assigned to be water equivalent (0 HU). The doses were compared to the dose calculated on the original planning CT image. Using the original HU values in the cone-beam images, the average dose del i vered by the plans from all 12 patients was I. I % lower than the intended 200 cOy delivered on the original CT plans (standard devia tion 0.7%, maximum difference -2.93%). When bulk electron densities were applied to the cone-beam images, the average dose was 0.3% lower than the original CT plans (standard deviation 0.8%, maximum difference -2.22%). Compared to using the original HU values, applying bulk electron densities to the CBCT images improved the dose calculations by almost I %. Some variation due to natural changes in anatomy should be expected. The application of bulk elec tron densities to cone beam CT images has the potential to improve the accuracy of dose calculations due to inaccurate H U values. Acknowledgements This work was partially funded by Cancer Council NSW Grant Number RG 07-06.
SU-E-T-161: Evaluation of Dose Calculation Based On Cone-Beam CT
International Nuclear Information System (INIS)
Abe, T; Nakazawa, T; Saitou, Y; Nakata, A; Yano, M; Tateoka, K; Fujimoto, K; Sakata, K
2014-01-01
Purpose: The purpose of this study is to convert pixel values in cone-beam CT (CBCT) using histograms of pixel values in the simulation CT (sim-CT) and the CBCT images and to evaluate the accuracy of dose calculation based on the CBCT. Methods: The sim-CT and CBCT images immediately before the treatment of 10 prostate cancer patients were acquired. Because of insufficient calibration of the pixel values in the CBCT, it is difficult to be directly used for dose calculation. The pixel values in the CBCT images were converted using an in-house program. A 7 fields treatment plans (original plan) created on the sim-CT images were applied to the CBCT images and the dose distributions were re-calculated with same monitor units (MUs). These prescription doses were compared with those of original plans. Results: In the results of the pixel values conversion in the CBCT images,the mean differences of pixel values for the prostate,subcutaneous adipose, muscle and right-femur were −10.78±34.60, 11.78±41.06, 29.49±36.99 and 0.14±31.15 respectively. In the results of the calculated doses, the mean differences of prescription doses for 7 fields were 4.13±0.95%, 0.34±0.86%, −0.05±0.55%, 1.35±0.98%, 1.77±0.56%, 0.89±0.69% and 1.69±0.71% respectively and as a whole, the difference of prescription dose was 1.54±0.4%. Conclusion: The dose calculation on the CBCT images achieve an accuracy of <2% by using this pixel values conversion program. This may enable implementation of efficient adaptive radiotherapy
Calculation of dose-rate conversion factors for external exposure to photons and electrons
International Nuclear Information System (INIS)
Kocher, D.C.
1978-01-01
Methods are presented for the calculation of dose-rate conversion factors for external exposure to photon and electron radiation from radioactive decay. A dose-rate conversion factor is defined as the dose-equivalent rate per unit radionuclide concentration. Exposure modes considered are immersion in contaminated air, immersion in contaminated water, and irradiation from a contaminated ground surface. For each radiation type and exposure mode, dose-rate conversion factors are derived for tissue-equivalent material at the body surface of an exposed individual. In addition, photon dose-rate conversion factors are estimated for 22 body organs. The calculations are based on the assumption that the exposure medium is infinite in extent and that the radionuclide concentration is uniform. The dose-rate conversion factors for immersion in contaminated air and water then follow from the requirement that all of the energy emitted in the radioactive decay is absorbed in the infinite medium. Dose-rate conversion factors for ground-surface exposure are calculated at a reference location above a smooth, infinite plane using the point-kernel integration method and known specific absorbed fractions for photons and electrons in air
Comparison of CT number calibration techniques for CBCT-based dose calculation
International Nuclear Information System (INIS)
Dunlop, Alex; McQuaid, Dualta; Nill, Simeon; Hansen, Vibeke N.; Oelfke, Uwe; Murray, Julia; Bhide, Shreerang; Harrington, Kevin; Poludniowski, Gavin; Nutting, Christopher; Newbold, Kate
2015-01-01
The aim of this work was to compare and validate various computed tomography (CT) number calibration techniques with respect to cone beam CT (CBCT) dose calculation accuracy. CBCT dose calculation accuracy was assessed for pelvic, lung, and head and neck (H and N) treatment sites for two approaches: (1) physics-based scatter correction methods (CBCT r ); (2) density override approaches including assigning water density to the entire CBCT (W), assignment of either water or bone density (WB), and assignment of either water or lung density (WL). Methods for CBCT density assignment within a commercially available treatment planning system (RS auto ), where CBCT voxels are binned into six density levels, were assessed and validated. Dose-difference maps and dose-volume statistics were used to compare the CBCT dose distributions with the ground truth of a planning CT acquired the same day as the CBCT. For pelvic cases, all CTN calibration methods resulted in average dose-volume deviations below 1.5 %. RS auto provided larger than average errors for pelvic treatments for patients with large amounts of adipose tissue. For H and N cases, all CTN calibration methods resulted in average dose-volume differences below 1.0 % with CBCT r (0.5 %) and RS auto (0.6 %) performing best. For lung cases, WL and RS auto methods generated dose distributions most similar to the ground truth. The RS auto density override approach is an attractive option for CTN adjustments for a variety of anatomical sites. RS auto methods were validated, resulting in dose calculations that were consistent with those calculated on diagnostic-quality CT images, for CBCT images acquired of the lung, for patients receiving pelvic RT in cases without excess adipose tissue, and for H and N cases. (orig.) [de
TU-AB-BRC-12: Optimized Parallel MonteCarlo Dose Calculations for Secondary MU Checks
Energy Technology Data Exchange (ETDEWEB)
French, S; Nazareth, D [Roswell Park Cancer Institute, Buffalo, NY (United States); Bellor, M [Lockheed Martin, Manassas, VA (United States)
2016-06-15
Purpose: Secondary MU checks are an important tool used during a physics review of a treatment plan. Commercial software packages offer varying degrees of theoretical dose calculation accuracy, depending on the modality involved. Dose calculations of VMAT plans are especially prone to error due to the large approximations involved. Monte Carlo (MC) methods are not commonly used due to their long run times. We investigated two methods to increase the computational efficiency of MC dose simulations with the BEAMnrc code. Distributed computing resources, along with optimized code compilation, will allow for accurate and efficient VMAT dose calculations. Methods: The BEAMnrc package was installed on a high performance computing cluster accessible to our clinic. MATLAB and PYTHON scripts were developed to convert a clinical VMAT DICOM plan into BEAMnrc input files. The BEAMnrc installation was optimized by running the VMAT simulations through profiling tools which indicated the behavior of the constituent routines in the code, e.g. the bremsstrahlung splitting routine, and the specified random number generator. This information aided in determining the most efficient compiling parallel configuration for the specific CPU’s available on our cluster, resulting in the fastest VMAT simulation times. Our method was evaluated with calculations involving 10{sup 8} – 10{sup 9} particle histories which are sufficient to verify patient dose using VMAT. Results: Parallelization allowed the calculation of patient dose on the order of 10 – 15 hours with 100 parallel jobs. Due to the compiler optimization process, further speed increases of 23% were achieved when compared with the open-source compiler BEAMnrc packages. Conclusion: Analysis of the BEAMnrc code allowed us to optimize the compiler configuration for VMAT dose calculations. In future work, the optimized MC code, in conjunction with the parallel processing capabilities of BEAMnrc, will be applied to provide accurate
SU-F-T-60: A Quick Dose Calculation Check for Accuboost Breast Treatment
Energy Technology Data Exchange (ETDEWEB)
Sen, A [Cancer Treatment Center of America, Tulsa, OK (United States)
2016-06-15
Purpose: Accuboost treatment planning uses dwell times from a nomogram designed with Monte Carlo calculations for round and D-shaped applicators. A quick dose calculation method has been developed for verification of the HDR Brachytherapy dose as a second check. Methods: Accuboost breast treatment uses several round and D-shaped applicators to be used non-invasively with an Ir-192 source from a HDR Brachytherapy afterloader after the breast is compressed in a mammographic unit for localization. The breast thickness, source activity, the prescription dose and the applicator size are entered into a nomogram spreadsheet which gives the dwell times to be manually entered into the delivery computer. Approximating the HDR Ir-192 as a point source, and knowing the geometry of the round and D-applicators, the distances from the source positions to the midpoint of the central plane are calculated. Using the exposure constant of Ir-192 and medium as human tissue, the dose at a point is calculated as: D(cGy) = 1.254 × A × t/R2, where A is the activity in Ci, t is the dwell time in sec and R is the distance in cm. The dose from each dwell position is added to get the total dose. Results: Each fraction is delivered in two compressions: cranio-caudally and medial-laterally. A typical APBI treatment in 10 fractions requires 20 compressions. For a patient treated with D45 applicators and an average of 5.22 cm thickness, this calculation was 1.63 % higher than the prescription. For another patient using D53 applicators in the CC direction and 7 cm SDO applicators in the ML direction, this calculation was 1.31 % lower than the prescription. Conclusion: This is a simple and quick method to double check the dose on the central plane for Accuboost treatment.
The denoising of Monte Carlo dose distributions using convolution superposition calculations
International Nuclear Information System (INIS)
El Naqa, I; Cui, J; Lindsay, P; Olivera, G; Deasy, J O
2007-01-01
Monte Carlo (MC) dose calculations can be accurate but are also computationally intensive. In contrast, convolution superposition (CS) offers faster and smoother results but by making approximations. We investigated MC denoising techniques, which use available convolution superposition results and new noise filtering methods to guide and accelerate MC calculations. Two main approaches were developed to combine CS information with MC denoising. In the first approach, the denoising result is iteratively updated by adding the denoised residual difference between the result and the MC image. Multi-scale methods were used (wavelets or contourlets) for denoising the residual. The iterations are initialized by the CS data. In the second approach, we used a frequency splitting technique by quadrature filtering to combine low frequency components derived from MC simulations with high frequency components derived from CS components. The rationale is to take the scattering tails as well as dose levels in the high-dose region from the MC calculations, which presumably more accurately incorporates scatter; high-frequency details are taken from CS calculations. 3D Butterworth filters were used to design the quadrature filters. The methods were demonstrated using anonymized clinical lung and head and neck cases. The MC dose distributions were calculated by the open-source dose planning method MC code with varying noise levels. Our results indicate that the frequency-splitting technique for incorporating CS-guided MC denoising is promising in terms of computational efficiency and noise reduction. (note)
NOTE: The denoising of Monte Carlo dose distributions using convolution superposition calculations
El Naqa, I.; Cui, J.; Lindsay, P.; Olivera, G.; Deasy, J. O.
2007-09-01
Monte Carlo (MC) dose calculations can be accurate but are also computationally intensive. In contrast, convolution superposition (CS) offers faster and smoother results but by making approximations. We investigated MC denoising techniques, which use available convolution superposition results and new noise filtering methods to guide and accelerate MC calculations. Two main approaches were developed to combine CS information with MC denoising. In the first approach, the denoising result is iteratively updated by adding the denoised residual difference between the result and the MC image. Multi-scale methods were used (wavelets or contourlets) for denoising the residual. The iterations are initialized by the CS data. In the second approach, we used a frequency splitting technique by quadrature filtering to combine low frequency components derived from MC simulations with high frequency components derived from CS components. The rationale is to take the scattering tails as well as dose levels in the high-dose region from the MC calculations, which presumably more accurately incorporates scatter; high-frequency details are taken from CS calculations. 3D Butterworth filters were used to design the quadrature filters. The methods were demonstrated using anonymized clinical lung and head and neck cases. The MC dose distributions were calculated by the open-source dose planning method MC code with varying noise levels. Our results indicate that the frequency-splitting technique for incorporating CS-guided MC denoising is promising in terms of computational efficiency and noise reduction.
Prior, Phillip; Tai, An; Erickson, Beth; Li, X Allen
2014-01-01
To consolidate duodenum and small bowel toxicity data from clinical studies with different dose fractionation schedules using the modified linear quadratic (MLQ) model. A methodology of adjusting the dose-volume (D,v) parameters to different levels of normal tissue complication probability (NTCP) was presented. A set of NTCP model parameters for duodenum toxicity were estimated by the χ(2) fitting method using literature-based tolerance dose and generalized equivalent uniform dose (gEUD) data. These model parameters were then used to convert (D,v) data into the isoeffective dose in 2 Gy per fraction, (D(MLQED2),v) and convert these parameters to an isoeffective dose at another NTCP (D(MLQED2'),v). The literature search yielded 5 reports useful in making estimates of duodenum and small bowel toxicity. The NTCP model parameters were found to be TD50(1)(model) = 60.9 ± 7.9 Gy, m = 0.21 ± 0.05, and δ = 0.09 ± 0.03 Gy(-1). Isoeffective dose calculations and toxicity rates associated with hypofractionated radiation therapy reports were found to be consistent with clinical data having different fractionation schedules. Values of (D(MLQED2'),v) between different NTCP levels remain consistent over a range of 5%-20%. MLQ-based isoeffective calculations of dose-response data corresponding to grade ≥2 duodenum toxicity were found to be consistent with one another within the calculation uncertainty. The (D(MLQED2),v) data could be used to determine duodenum and small bowel dose-volume constraints for new dose escalation strategies. Copyright © 2014 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.
Recent developments in biokinetic models and the calculation of internal dose coefficients
International Nuclear Information System (INIS)
Fell, T.P.; Phipps, A.W.; Kendall, G.M.; Stradling, G.N.
1997-01-01
In most cases the measurement of radioactivity in an environmental or biological sample will be followed by some estimation of dose and possibly risk, either to a population or an individual. This will normally involve the use of a dose coefficient (dose per unit intake value) taken from a compendium. In recent years the calculation of dose coefficients has seen many developments in both biokinetic modelling and computational capabilities. ICRP has recommended new models for the respiratory tract and for the systemic behavior of many of the more important elements. As well as this, a general age-dependent calculation method has been developed which involves an effectively continuous variation of both biokinetic and dosimetric parameters, facilitating more realistic estimation of doses to young people. These new developments were used in work for recent ICRP, IAEA and CEC compendia of dose coefficients for both members of the public (including children) and workers. This paper presents a general overview of the method of calculation of internal doses with particular reference to the actinides. Some of the implications for dose coefficients of the new models are discussed. For example it is shown that compared with data in ICRP Publications 30 and 54: the new respiratory tract model generally predicts lower deposition in systemic tissues per unit intake; the new biokinetic models for actinides allow for burial of material deposited on bone surfaces; age-dependent models generally feature faster turnover of material in young people. All of these factors can lead to substantially different estimates of dose and examples of the new dose coefficients are given to illustrate these differences. During the development of the new models for actinides, human bioassay data were used to validate the model. Thus, one would expect the new models to give reasonable predictions of bioassay quantities. Some examples of the bioassay applications, e.g., excretion data for the
International Nuclear Information System (INIS)
Kan, M W K; Cheung, J Y C; Leung, L H T; Lau, B M F; Yu, P K N
2011-01-01
Nasopharyngeal tumors are commonly treated with intensity-modulated radiotherapy techniques. For photon dose calculations, problems related to loss of lateral electronic equilibrium exist when small fields are used. The anisotropic analytical algorithm (AAA) implemented in Varian Eclipse was developed to replace the pencil beam convolution (PBC) algorithm for more accurate dose prediction in an inhomogeneous medium. The purpose of this study was to investigate the accuracy of the AAA for predicting interface doses for intensity-modulated stereotactic radiotherapy boost of nasopharyngeal tumors. The central axis depth dose data and dose profiles of phantoms with rectangular air cavities for small fields were measured using a 6 MV beam. In addition, the air-tissue interface doses from six different intensity-modulated stereotactic radiotherapy plans were measured in an anthropomorphic phantom. The nasopharyngeal region of the phantom was especially modified to simulate the air cavities of a typical patient. The measured data were compared to the data calculated by both the AAA and the PBC algorithm. When using single small fields in rectangular air cavity phantoms, both AAA and PBC overestimated the central axis dose at and beyond the first few millimeters of the air-water interface. Although the AAA performs better than the PBC algorithm, its calculated interface dose could still be more than three times that of the measured dose when a 2 x 2 cm 2 field was used. Testing of the algorithms using the anthropomorphic phantom showed that the maximum overestimation by the PBC algorithm was 20.7%, while that by the AAA was 8.3%. When multiple fields were used in a patient geometry, the dose prediction errors of the AAA would be substantially reduced compared with those from a single field. However, overestimation of more than 3% could still be found at some points at the air-tissue interface.
Influence of metallic dental implants and metal artefacts on dose calculation accuracy.
Maerz, Manuel; Koelbl, Oliver; Dobler, Barbara
2015-03-01
Metallic dental implants cause severe streaking artefacts in computed tomography (CT) data, which inhibit the correct representation of shape and density of the metal and the surrounding tissue. The aim of this study was to investigate the impact of dental implants on the accuracy of dose calculations in radiation therapy planning and the benefit of metal artefact reduction (MAR). A second aim was to determine the treatment technique which is less sensitive to the presence of metallic implants in terms of dose calculation accuracy. Phantoms consisting of homogeneous water equivalent material surrounding dental implants were designed. Artefact-containing CT data were corrected using the correct density information. Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were calculated on corrected and uncorrected CT data and compared to 2-dimensional dose measurements using GafChromic™ EBT2 films. For all plans the accuracy of dose calculations is significantly higher if performed on corrected CT data (p = 0.015). The agreement of calculated and measured dose distributions is significantly higher for VMAT than for IMRT plans for calculations on uncorrected CT data (p = 0.011) as well as on corrected CT data (p = 0.029). For IMRT and VMAT the application of metal artefact reduction significantly increases the agreement of dose calculations with film measurements. VMAT was found to provide the highest accuracy on corrected as well as on uncorrected CT data. VMAT is therefore preferable over IMRT for patients with metallic implants, if plan quality is comparable for the two techniques.
Influence of metallic dental implants and metal artefacts on dose calculation accuracy
International Nuclear Information System (INIS)
Maerz, Manuel; Koelbl, Oliver; Dobler, Barbara
2015-01-01
Metallic dental implants cause severe streaking artefacts in computed tomography (CT) data, which inhibit the correct representation of shape and density of the metal and the surrounding tissue. The aim of this study was to investigate the impact of dental implants on the accuracy of dose calculations in radiation therapy planning and the benefit of metal artefact reduction (MAR). A second aim was to determine the treatment technique which is less sensitive to the presence of metallic implants in terms of dose calculation accuracy. Phantoms consisting of homogeneous water equivalent material surrounding dental implants were designed. Artefact-containing CT data were corrected using the correct density information. Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were calculated on corrected and uncorrected CT data and compared to 2-dimensional dose measurements using GafChromic trademark EBT2 films. For all plans the accuracy of dose calculations is significantly higher if performed on corrected CT data (p = 0.015). The agreement of calculated and measured dose distributions is significantly higher for VMAT than for IMRT plans for calculations on uncorrected CT data (p = 0.011) as well as on corrected CT data (p = 0.029). For IMRT and VMAT the application of metal artefact reduction significantly increases the agreement of dose calculations with film measurements. VMAT was found to provide the highest accuracy on corrected as well as on uncorrected CT data. VMAT is therefore preferable over IMRT for patients with metallic implants, if plan quality is comparable for the two techniques. (orig.) [de
Dose Distribution Calculation Using MCNPX Code in the Gamma-ray Irradiation Cell
International Nuclear Information System (INIS)
Kim, Yong Ho
1991-02-01
60 Co-gamma irradiators have long been used for foods sterilization, plant mutation and development of radio-protective agents, radio-sensitizers and other purposes. The Applied Radiological Science Research Institute of Cheju National University has a multipurpose gamma irradiation facility loaded with a MDS Nordin standard 60 Co source (C188), of which the initial activity was 400 TBq (10,800 Ci) on February 19, 2004. This panoramic gamma irradiator is designed to irradiate in all directions various samples such as plants, cultured cells and mice to administer given radiation doses. In order to give accurate doses to irradiation samples, appropriate methods of evaluating, both by calculation and measurement, the radiation doses delivered to the samples should be set up. Computational models have been developed to evaluate the radiation dose distributions inside the irradiation chamber and the radiation doses delivered to typical biolological samples which are frequently irradiated in the facility. The computational models are based on using the MCNPX code. The horizontal and vertical dose distributions has been calculated inside the irradiation chamber and compared the calculated results with measured data obtained with radiation dosimeters to verify the computational models. The radiation dosimeters employed are a Famer's type ion chamber and MOSFET dosimeters. Radiation doses were calculated by computational models, which were delivered to cultured cell samples contained in test tubes and to a mouse fixed in a irradiation cage, and compared the calculated results with the measured data. The computation models are also tested to see if they can accurately simulate the case where a thick lead shield is placed between the source and detector. Three tally options of the MCNPX code, F4, F5 and F6, are alternately used to see which option produces optimum results. The computation models are also used to calculate gamma ray energy spectra of a BGO scintillator at
Monte Carlo calculations of lung dose in ORNL phantom for boron neutron capture therapy
International Nuclear Information System (INIS)
Krstic, D.; Markovic, V.M.; Jovanovic, Z.; Milenkovic, B.; Nikezic, D.; Atanackovic, J.
2014-01-01
Monte Carlo simulations were performed to evaluate dose for possible treatment of cancers by boron neutron capture therapy (BNCT). The computational model of male Oak Ridge National Laboratory (ORNL) phantom was used to simulate tumours in the lung. Calculations have been performed by means of the MCNP5/X code. In this simulation, two opposite neutron beams were considered, in order to obtain uniform neutron flux distribution inside the lung. The obtained results indicate that the lung cancer could be treated by BNCT under the assumptions of calculations. The difference in evaluated dose in cancer and normal lung tissue suggests that BNCT could be applied for the treatment of cancers. The difference in exposure of cancer and healthy tissue can be observed, so the healthy tissue can be spared from damage. An absorbed dose ratio of metastatic tissue-to-the healthy tissue was ∼5. Absorbed dose to all other organs was low when compared with the lung dose. Absorbed dose depth distribution shows that BNC therapy can be very useful in the treatments for tumour. The ratio of the tumour absorbed dose and irradiated healthy tissue absorbed dose was also ∼5. It was seen that an elliptical neutron field was better irradiation choice. (authors)
A calculation of dose distribution around 32P spherical sources and its clinical application
International Nuclear Information System (INIS)
Ohara, Ken; Tanaka, Yoshiaki; Nishizawa, Kunihide; Maekoshi, Hisashi
1977-01-01
In order to avoid the radiation hazard in radiation therapy of craniopharyngioma by using 32 P, it is helpful to prepare a detailed dose distribution in the vicinity of the source in the tissue. Valley's method is used for calculations. A problem of the method is pointed out and the method itself is refined numerically: it extends a region of xi where an approximate polynomial is available, and it determines an optimum degree of the polynomial as 9. Usefulness of the polynomial is examined by comparing with Berger's scaled absorbed dose distribution F(xi) and the Valley's result. The dose and dose rate distributions around uniformly distributed spherical sources are computed from the termwise integration of our polynomial of degree 9 over the range of xi from 0 to 1.7. The dose distributions calculated from the spherical surface to a point at 0.5 cm outside the source, are given, when the radii of sources are 0.5, 0.6, 0.7, 1.0, and 1.5 cm respectively. The therapeutic dose for a craniopharyngioma which has a spherically shaped cyst, and the absorbed dose to the normal tissue, (oculomotor nerve), are obtained from these dose rate distributions. (auth.)
Directory of Open Access Journals (Sweden)
Takashi Kadowaki
Full Text Available BACKGROUND: Pragmatic methods for dose optimization are required for the successful basal management in daily clinical practice. To derive a useful formula for calculating recommended glargine doses, we analyzed data from the Add-on Lantus® to Oral Hypoglycemic Agents (ALOHA study, a 24-week observation of Japanese type 2 diabetes patients. METHODOLOGY/PRINCIPAL FINDINGS: The patients who initiated insulin glargine in basal-supported oral therapy (BOT regimen (n = 3506 were analyzed. The correlations between average changes in glargine dose and HbA1c were calculated, and its regression formula was estimated from grouped data categorized by baseline HbA1c levels. Starting doses of the background-subgroup achieving the HbA1c target with a last-observed dose above the average were compared to an assumed optimal starting dose of 0.15 U/kg/day. The difference in regression lines between background-subgroups was examined. A formula for determining the optimal starting and titration doses was thereby derived. The correlation coefficient between changes in dose and HbA1c was -0.9043. The estimated regression line formula was -0.964 × change in HbA1c+2.000. A starting dose of 0.15 U/kg/day was applicable to all background-subgroups except for patients with retinopathy (0.120 U/kg/day and/or with eGFR<60 mL/min/1.73 m(2 (0.114 U/kg/day. Additionally, women (0.135 U/kg/day and patients with sulfonylureas (0.132 U/kg/day received a slightly decreased starting dose. CONCLUSIONS/SIGNIFICANCE: We suggest a simplified and pragmatic dose calculation formula for type 2 diabetes patients starting glargine BOT optimal daily dose at 24 weeks = starting dose (0.15×weight + incremental dose (baseline HbA1c - target HbA1c+2. This formula should be further validated using other samples in a prospective follow-up, especially since several patient groups required lower starting doses.
International Nuclear Information System (INIS)
Wan, H; Tseung, Chan; Beltran, C
2016-01-01
Purpose: To demonstrate fast and accurate Monte Carlo (MC) calculations of proton dose-averaged linear energy transfer (LETd) and biological dose (BD) on a Graphics Processing Unit (GPU) card. Methods: A previously validated GPU-based MC simulation of proton transport was used to rapidly generate LETd distributions for proton treatment plans. Since this MC handles proton-nuclei interactions on an event-by-event using a Bertini intranuclear cascade-evaporation model, secondary protons were taken into account. The smaller contributions of secondary neutrons and recoil nuclei were ignored. Recent work has shown that LETd values are sensitive to the scoring method. The GPU-based LETd calculations were verified by comparing with a TOPAS custom scorer that uses tabulated stopping powers, following recommendations by other authors. Comparisons were made for prostate and head-and-neck patients. A python script is used to convert the MC-generated LETd distributions to BD using a variety of published linear quadratic models, and to export the BD in DICOM format for subsequent evaluation. Results: Very good agreement is obtained between TOPAS and our GPU MC. Given a complex head-and-neck plan with 1 mm voxel spacing, the physical dose, LETd and BD calculations for 10"8 proton histories can be completed in ∼5 minutes using a NVIDIA Titan X card. The rapid turnover means that MC feedback can be obtained on dosimetric plan accuracy as well as BD hotspot locations, particularly in regards to their proximity to critical structures. In our institution the GPU MC-generated dose, LETd and BD maps are used to assess plan quality for all patients undergoing treatment. Conclusion: Fast and accurate MC-based LETd calculations can be performed on the GPU. The resulting BD maps provide valuable feedback during treatment plan review. Partially funded by Varian Medical Systems.
Energy Technology Data Exchange (ETDEWEB)
Wan, H; Tseung, Chan; Beltran, C [Mayo Clinic, Rochester, MN (United States)
2016-06-15
Purpose: To demonstrate fast and accurate Monte Carlo (MC) calculations of proton dose-averaged linear energy transfer (LETd) and biological dose (BD) on a Graphics Processing Unit (GPU) card. Methods: A previously validated GPU-based MC simulation of proton transport was used to rapidly generate LETd distributions for proton treatment plans. Since this MC handles proton-nuclei interactions on an event-by-event using a Bertini intranuclear cascade-evaporation model, secondary protons were taken into account. The smaller contributions of secondary neutrons and recoil nuclei were ignored. Recent work has shown that LETd values are sensitive to the scoring method. The GPU-based LETd calculations were verified by comparing with a TOPAS custom scorer that uses tabulated stopping powers, following recommendations by other authors. Comparisons were made for prostate and head-and-neck patients. A python script is used to convert the MC-generated LETd distributions to BD using a variety of published linear quadratic models, and to export the BD in DICOM format for subsequent evaluation. Results: Very good agreement is obtained between TOPAS and our GPU MC. Given a complex head-and-neck plan with 1 mm voxel spacing, the physical dose, LETd and BD calculations for 10{sup 8} proton histories can be completed in ∼5 minutes using a NVIDIA Titan X card. The rapid turnover means that MC feedback can be obtained on dosimetric plan accuracy as well as BD hotspot locations, particularly in regards to their proximity to critical structures. In our institution the GPU MC-generated dose, LETd and BD maps are used to assess plan quality for all patients undergoing treatment. Conclusion: Fast and accurate MC-based LETd calculations can be performed on the GPU. The resulting BD maps provide valuable feedback during treatment plan review. Partially funded by Varian Medical Systems.
Bone - marrow postirradiation syndrome
International Nuclear Information System (INIS)
Sesztakova, E.; Bilek, J.; Benova, K.; Novakova, J.; Culenova, K.
2006-01-01
Quantitative and qualitative changes in haemopoietic cells in chicken bone Marrow were investigated after acute single irradiation with doses 4.5 Gy and 5 Gy. Samples of bone marrow were obtained from proximal femoral epiphysis of decapitated chickens. Marrow smears were prepared and stained according to Pappenheim. Qualitative examination of myelogram showed proliferation of adipose tissue, hypocellularity, caryolyosis, caryorexis, disintegration of cells and proliferation of cells which could not be differentiated. Quantitative examination revealed high radiosensitivity of blast cells and lymphocytes shortly after irradiation. (authors)
Independent dose calculation of the Tps Iplan in radiotherapy conformed with MLC
International Nuclear Information System (INIS)
Adrada, A.; Tello, Z.; Medina, L.; Garrigo, E.; Venencia, D.
2014-08-01
The systems utilization of independent dose calculation in three dimensional-Conformal Radiation Therapy (3D-Crt) treatments allows a direct verification of the treatments times. The utilization of these systems allows diminishing the probability of errors occurrence generated by the treatment planning system (Tps), allowing a detailed analysis of the dose to delivering and review of the normalization point (Np) or prescription. The independent dose calculation is realized across the knowledge of dosimetric parameters of the treatment machine and particular characteristics of every individual field. The aim of this work is develops a calculation system of punctual doses for isocentric fields conformed with multi-leaf collimation systems (MLC), where the dose calculation is in conformity with the suggested ones by ICRU Report No. 42, 1987. Calculation software was realized in C ++ under a free platform of programming (Code::Blocks). The system uses files in format Rtp, exported from the Tps to systems of record and verification (Lantis). This file contains detailed information of the dose, Um, position of the MLC sheets and collimators for every field of treatment. The size of equivalent field is obtained from the positions of every sheet; the effective depth of calculation can be introduced from the dosimetric report of the Tps or automatically from the DFS of the field. The 3D coordinates of the isocenter and the Np for the treatment plan must be introduced manually. From this information the system looks the dosimetric parameters and calculates the Um. The calculations were realized in two accelerators a NOVALIS Tx (Varian) with 120 sheets of high definition (hd-MLC) and a PRIMUS Optifocus (Siemens) with 82 sheets. 705 patients were analyzed for a total of 1082, in plans made for both equipment s, the average uncertainty with regard to the calculation of the Tps is-0.43% ± 2.42% in a range between [-7.90 %, 7.50 %]. The major uncertainty was in Np near of the
Monte Carlo dose calculation improvements for low energy electron beams using eMC
International Nuclear Information System (INIS)
Fix, Michael K; Frei, Daniel; Volken, Werner; Born, Ernst J; Manser, Peter; Neuenschwander, Hans
2010-01-01
The electron Monte Carlo (eMC) dose calculation algorithm in Eclipse (Varian Medical Systems) is based on the macro MC method and is able to predict dose distributions for high energy electron beams with high accuracy. However, there are limitations for low energy electron beams. This work aims to improve the accuracy of the dose calculation using eMC for 4 and 6 MeV electron beams of Varian linear accelerators. Improvements implemented into the eMC include (1) improved determination of the initial electron energy spectrum by increased resolution of mono-energetic depth dose curves used during beam configuration; (2) inclusion of all the scrapers of the applicator in the beam model; (3) reduction of the maximum size of the sphere to be selected within the macro MC transport when the energy of the incident electron is below certain thresholds. The impact of these changes in eMC is investigated by comparing calculated dose distributions for 4 and 6 MeV electron beams at source to surface distance (SSD) of 100 and 110 cm with applicators ranging from 6 x 6 to 25 x 25 cm 2 of a Varian Clinac 2300C/D with the corresponding measurements. Dose differences between calculated and measured absolute depth dose curves are reduced from 6% to less than 1.5% for both energies and all applicators considered at SSD of 100 cm. Using the original eMC implementation, absolute dose profiles at depths of 1 cm, d max and R50 in water lead to dose differences of up to 8% for applicators larger than 15 x 15 cm 2 at SSD 100 cm. Those differences are now reduced to less than 2% for all dose profiles investigated when the improved version of eMC is used. At SSD of 110 cm the dose difference for the original eMC version is even more pronounced and can be larger than 10%. Those differences are reduced to within 2% or 2 mm with the improved version of eMC. In this work several enhancements were made in the eMC algorithm leading to significant improvements in the accuracy of the dose calculation
Monte Carlo dose calculation improvements for low energy electron beams using eMC.
Fix, Michael K; Frei, Daniel; Volken, Werner; Neuenschwander, Hans; Born, Ernst J; Manser, Peter
2010-08-21
The electron Monte Carlo (eMC) dose calculation algorithm in Eclipse (Varian Medical Systems) is based on the macro MC method and is able to predict dose distributions for high energy electron beams with high accuracy. However, there are limitations for low energy electron beams. This work aims to improve the accuracy of the dose calculation using eMC for 4 and 6 MeV electron beams of Varian linear accelerators. Improvements implemented into the eMC include (1) improved determination of the initial electron energy spectrum by increased resolution of mono-energetic depth dose curves used during beam configuration; (2) inclusion of all the scrapers of the applicator in the beam model; (3) reduction of the maximum size of the sphere to be selected within the macro MC transport when the energy of the incident electron is below certain thresholds. The impact of these changes in eMC is investigated by comparing calculated dose distributions for 4 and 6 MeV electron beams at source to surface distance (SSD) of 100 and 110 cm with applicators ranging from 6 x 6 to 25 x 25 cm(2) of a Varian Clinac 2300C/D with the corresponding measurements. Dose differences between calculated and measured absolute depth dose curves are reduced from 6% to less than 1.5% for both energies and all applicators considered at SSD of 100 cm. Using the original eMC implementation, absolute dose profiles at depths of 1 cm, d(max) and R50 in water lead to dose differences of up to 8% for applicators larger than 15 x 15 cm(2) at SSD 100 cm. Those differences are now reduced to less than 2% for all dose profiles investigated when the improved version of eMC is used. At SSD of 110 cm the dose difference for the original eMC version is even more pronounced and can be larger than 10%. Those differences are reduced to within 2% or 2 mm with the improved version of eMC. In this work several enhancements were made in the eMC algorithm leading to significant improvements in the accuracy of the dose
SU-E-T-202: Impact of Monte Carlo Dose Calculation Algorithm On Prostate SBRT Treatments
Energy Technology Data Exchange (ETDEWEB)
Venencia, C; Garrigo, E; Cardenas, J; Castro Pena, P [Instituto de Radioterapia - Fundacion Marie Curie, Cordoba (Argentina)
2014-06-01
Purpose: The purpose of this work was to quantify the dosimetric impact of using Monte Carlo algorithm on pre calculated SBRT prostate treatment with pencil beam dose calculation algorithm. Methods: A 6MV photon beam produced by a Novalis TX (BrainLAB-Varian) linear accelerator equipped with HDMLC was used. Treatment plans were done using 9 fields with Iplanv4.5 (BrainLAB) and dynamic IMRT modality. Institutional SBRT protocol uses a total dose to the prostate of 40Gy in 5 fractions, every other day. Dose calculation is done by pencil beam (2mm dose resolution), heterogeneity correction and dose volume constraint (UCLA) for PTV D95%=40Gy and D98%>39.2Gy, Rectum V20Gy<50%, V32Gy<20%, V36Gy<10% and V40Gy<5%, Bladder V20Gy<40% and V40Gy<10%, femoral heads V16Gy<5%, penile bulb V25Gy<3cc, urethra and overlap region between PTV and PRV Rectum Dmax<42Gy. 10 SBRT treatments plans were selected and recalculated using Monte Carlo with 2mm spatial resolution and mean variance of 2%. DVH comparisons between plans were done. Results: The average difference between PTV doses constraints were within 2%. However 3 plans have differences higher than 3% which does not meet the D98% criteria (>39.2Gy) and should have been renormalized. Dose volume constraint differences for rectum, bladder, femoral heads and penile bulb were les than 2% and within tolerances. Urethra region and overlapping between PTV and PRV Rectum shows increment of dose in all plans. The average difference for urethra region was 2.1% with a maximum of 7.8% and for the overlapping region 2.5% with a maximum of 8.7%. Conclusion: Monte Carlo dose calculation on dynamic IMRT treatments could affects on plan normalization. Dose increment in critical region of urethra and PTV overlapping region with PTV could have clinical consequences which need to be studied. The use of Monte Carlo dose calculation algorithm is limited because inverse planning dose optimization use only pencil beam.
Calculation of electron contamination doses produced using blocking trays for 6 MV X-rays
Energy Technology Data Exchange (ETDEWEB)
Butson, M.J. E-mail: mbutson@guessmail.com; Cheung Tsang; Yu, P.K.N
2002-04-01
Calculation of electron contamination doses whilst using blocking trays in radiotherapy is achieved by comparison of measured absorbed dose within the first few centimeters of a water phantom. Electron contamination of up to 28% of maximum dose is produced at the central axis of the beam whilst using a 6 mm Perspex blocking tray for a 30 cmx30 cm field. The electron contamination is spread over the entire field reducing slightly towards the edge of the beam. Electron contamination from block trays is also present outside the primary collimated X-ray beam with more than 20% of the maximum dose deposited at the surface, 5 cm outside the primary collimated beam at a field size of 40 cmx40 cm. The electron contamination spectrum has been calculated from measured results.
SKYSHIN: A computer code for calculating radiation dose over a barrier
International Nuclear Information System (INIS)
Atwood, C.L.; Boland, J.R.; Dickman, P.T.
1986-11-01
SKYSHIN is a computer code for calculating the radioactive dose (mrem), when there is a barrier between the point source and the receptor. The two geometrical configurations considered are: the source and receptor separated by a rectangular wall, and the source at the bottom of a cylindrical hole in the ground. Each gamma ray traveling over the barrier is assumed to be scattered at a single point. The dose to a receptor from such paths is numerically integrated for the total dose, with symmetry used to reduce the triple integral to a double integral. The buildup factor used along a straight line through air is based on published data, and extrapolated in a stable way to low energy levels. This buildup factor was validated by comparing calculated and experimental line-of-sight doses. The entire code shows good agreement to limited field data. The code runs on a CDC or on a Vax computer, and could be modified easily for others
Calculational methods for estimating skin dose from electrons in Co-60 gamma-ray beams
International Nuclear Information System (INIS)
Higgins, P.D.; Sibata, C.H.; Attix, F.H.; Paliwal, B.R.
1983-01-01
Several methods have been employed to calculate the relative contribution to skin dose due to scattered electrons in Co-60 gamma-ray beams. Either the Klein-Nishina differential scattering probability is employed to determine the number and initial energy of electrons scattered into the direction of a detector, or a Gaussian approximation is used to specify the surface distribution of initial pencil electron beams created by parallel or diverging photon fields. Results of these calculations are compared with experimental data. In addition, that fraction of relative surface dose resulting from photon interactions in air alone is estimated and compared with data extrapolated from measurements at large source-surface distance (SSD). The contribution to surface dose from electrons generated in air is 50% or more of the total skin dose for SSDs greater than 80 cm
Calculational methods for estimating skin dose from electrons in Co-60 gamma-ray beams
International Nuclear Information System (INIS)
Higgins, P.D.; Sibata, C.H.; Attix, F.H.; Paliwal, B.R.
1983-01-01
Several methods have been employed to calculate the relative contribution to skin dose due to scattered electrons in Co-60 γ-ray beams. Either the Klein--Nishina differential scattering probability is employed to determine the number and initial energy of electrons scattered into the direction of a detector, or a Gaussian approximation is used to specify the surface distribution of initial pencil electron beams created by parallel or diverging photon fields. Results of these calculations are compared with experimental data. In addition, that fraction of relative surface dose resulting from photon interactions in air alone is estimated and compared with data extrapolated from measurements at large source--surface distance (SSD). The contribution to surface dose from electrons generated in air is 50% or more of the total skin dose for SSDs greater than 80 cm
Development of Japanese voxel models and their application to organ dose calculation
International Nuclear Information System (INIS)
Sato, Kaoru; Endo, Akira; Saito, Kimiaki
2007-01-01
Three Japanese voxel (volume pixel) phantoms in supine and upright postures, which are consisted of about 1 mm 3 size voxels, have been developed on the basis of computed tomography (CT) images of healthy Japanese adult male and female volunteers. Their body structures are reproduced more realistically in comparison with most existing voxel phantoms. Organ doses due to internal or external exposures were calculated using the developed phantoms. In estimation of radiation dose from radionuclides incorporated into body, specific absorbed fractions (SAFs) for low energy photon were significantly influenced by the changes in postures. In estimation of organ doses due to external exposures, the doses of some organs of the developed phantom were calculated and were compared with those of a previous Japanese voxel phantom (voxel size: 0.98x0.98x10 mm 3 ) and the reference values of ICRP Publication 74. (author)
International Nuclear Information System (INIS)
Kirisits, Christian; Wexberg, Paul; Gottsauner-Wolf, Michael; Pokrajac, Boris; Ortmann, Elisabeth; Aiginger, Hannes; Glogar, Dietmar; Poetter, Richard
2001-01-01
Background and purpose: Radioactive stents are under investigation for reduction of coronary restenosis. However, the actual dose delivered to specific parts of the coronary artery wall based on the individual vessel anatomy has not been determined so far. Dose-volume histograms (DVHs) permit an estimation of the actual dose absorbed by the target volume. We present a method to calculate DVHs based on intravascular ultrasound (IVUS) measurements to determine the dose distribution within the vessel wall. Materials and methods: Ten patients were studied by intravascular ultrasound after radioactive stenting (BX Stent, P-32, 15-mm length) to obtain tomographic cross-sections of the treated segments. We developed a computer algorithm using the actual dose distribution of the stent to calculate differential and cumulative DVHs. The minimal target dose, the mean target dose, the minimal doses delivered to 10 and 90% of the adventitia (DV10, DV90), and the percentage of volume receiving a reference dose at 0.5 mm from the stent surface cumulated over 28 days were derived from the DVH plots. Results were expressed as mean±SD. Results: The mean activity of the stents was 438±140 kBq at implantation. The mean reference dose was 111±35 Gy, whereas the calculated mean target dose within the adventitia along the stent was 68±20 Gy. On average, DV90 and DV10 were 33±9 Gy and 117±41 Gy, respectively. Expanding the target volume to include 2.5-mm-long segments at the proximal and distal ends of the stent, the calculated mean target dose decreased to 55±17 Gy, and DV 90 and DV 10 were 6.4±2.4 Gy and 107±36 Gy, respectively. Conclusions: The assessment of DVHs seems in principle to be a valuable tool for both prospective and retrospective analysis of dose-distribution of radioactive stents. It may provide the basis to adapt treatment planning in coronary brachytherapy to the common standards of radiotherapy
3D calculation of absorbed dose for 131I-targeted radiotherapy: A Monte Carlo study
International Nuclear Information System (INIS)
Saeedzadeh, E.; Sarkar, S.; Abbaspour Tehrani-Fard, A.; Ay, M. R.; Khosravi, H. R.; Loudos, G.
2008-01-01
Various methods, such as those developed by the Medical Internal Radiation Dosimetry (MIRD) Committee of the Society of Nuclear Medicine or employing dose point kernels, have been applied to the radiation dosimetry of 131 I radionuclide therapy. However, studies have not shown a strong relationship between tumour absorbed dose and its overall therapeutic response, probably due in part to inaccuracies in activity and dose estimation. In the current study, the GATE Monte Carlo computer code was used to facilitate voxel-level radiation dosimetry for organ activities measured in an. 131 I-treated thyroid cancer patient. This approach allows incorporation of the size, shape and composition of organs (in the current study, in the Zubal anthropomorphic phantom) and intra-organ and intra-tumour inhomogeneities in the activity distributions. The total activities of the tumours and their heterogeneous distributions were measured from the SPECT images to calculate the dose maps. For investigating the effect of activity distribution on dose distribution, a hypothetical homogeneous distribution of the same total activity was considered in the tumours. It was observed that the tumour mean absorbed dose rates per unit cumulated activity were 0.65 E-5 and 0.61 E-5 mGY MBq -1 s -1 for the uniform and non-uniform distributions in the tumour, respectively, which do not differ considerably. However, the dose-volume histograms (DVH) show that the tumour non-uniform activity distribution decreases the absorbed dose to portions of the tumour volume. In such a case, it can be misleading to quote the mean or maximum absorbed dose, because overall response is likely limited by the tumour volume that receives low (i.e. non-cytocidal) doses. Three-dimensional radiation dosimetry, and calculation of tumour DVHs, may lead to the derivation of clinically reliable dose-response relationships and therefore may ultimately improve treatment planning as well as response assessment for radionuclide
Lesperance, Marielle; Inglis-Whalen, M; Thomson, R M
2014-02-01
To investigate the effects of the composition and geometry of ocular media and tissues surrounding the eye on dose distributions for COMS eye plaque brachytherapy with(125)I, (103)Pd, or (131)Cs seeds, and to investigate doses to ocular structures. An anatomically and compositionally realistic voxelized eye model with a medial tumor is developed based on a literature review. Mass energy absorption and attenuation coefficients for ocular media are calculated. Radiation transport and dose deposition are simulated using the EGSnrc Monte Carlo user-code BrachyDose for a fully loaded COMS eye plaque within a water phantom and our full eye model for the three radionuclides. A TG-43 simulation with the same seed configuration in a water phantom neglecting the plaque and interseed effects is also performed. The impact on dose distributions of varying tumor position, as well as tumor and surrounding tissue media is investigated. Each simulation and radionuclide is compared using isodose contours, dose volume histograms for the lens and tumor, maximum, minimum, and average doses to structures of interest, and doses to voxels of interest within the eye. Mass energy absorption and attenuation coefficients of the ocular media differ from those of water by as much as 12% within the 20-30 keV photon energy range. For all radionuclides studied, average doses to the tumor and lens regions in the full eye model differ from those for the plaque in water by 8%-10% and 13%-14%, respectively; the average doses to the tumor and lens regions differ between the full eye model and the TG-43 simulation by 2%-17% and 29%-34%, respectively. Replacing the surrounding tissues in the eye model with water increases the maximum and average doses to the lens by 2% and 3%, respectively. Substituting the tumor medium in the eye model for water, soft tissue, or an alternate melanoma composition affects tumor dose compared to the default eye model simulation by up to 16%. In the full eye model
International Nuclear Information System (INIS)
Lesperance, Marielle; Inglis-Whalen, M.; Thomson, R. M.
2014-01-01
Purpose : To investigate the effects of the composition and geometry of ocular media and tissues surrounding the eye on dose distributions for COMS eye plaque brachytherapy with 125 I, 103 Pd, or 131 Cs seeds, and to investigate doses to ocular structures. Methods : An anatomically and compositionally realistic voxelized eye model with a medial tumor is developed based on a literature review. Mass energy absorption and attenuation coefficients for ocular media are calculated. Radiation transport and dose deposition are simulated using the EGSnrc Monte Carlo user-code BrachyDose for a fully loaded COMS eye plaque within a water phantom and our full eye model for the three radionuclides. A TG-43 simulation with the same seed configuration in a water phantom neglecting the plaque and interseed effects is also performed. The impact on dose distributions of varying tumor position, as well as tumor and surrounding tissue media is investigated. Each simulation and radionuclide is compared using isodose contours, dose volume histograms for the lens and tumor, maximum, minimum, and average doses to structures of interest, and doses to voxels of interest within the eye. Results : Mass energy absorption and attenuation coefficients of the ocular media differ from those of water by as much as 12% within the 20–30 keV photon energy range. For all radionuclides studied, average doses to the tumor and lens regions in the full eye model differ from those for the plaque in water by 8%–10% and 13%–14%, respectively; the average doses to the tumor and lens regions differ between the full eye model and the TG-43 simulation by 2%–17% and 29%–34%, respectively. Replacing the surrounding tissues in the eye model with water increases the maximum and average doses to the lens by 2% and 3%, respectively. Substituting the tumor medium in the eye model for water, soft tissue, or an alternate melanoma composition affects tumor dose compared to the default eye model simulation by up
Interpretation of animal data in the calculation of doses from new radiolabelled compounds
International Nuclear Information System (INIS)
Ellender, M.; Naylor, G.P.L.
1992-01-01
The Radionuclide Biokinetics Group of the Biomedical Effects Department at NRPB provides a dose calculation service for pharmaceutical companies and associated laboratories which plan to administer radiolabelled drugs to human volunteers as part of their research and development programmes for new compounds. Animal data provided by these companies are used to estimate the likely doses to humans from administration of the compound. The dose estimate then accompanies the pharmaceutical company's application for approval from the UK Administration of Radioactive Substances Advisory Committee (ARSAC). The method of calculation, the interpretation of the animal data and the range of results obtained are discussed. In addition, the effect of the use of the new ICRP tissue weighting factors in the calculations is considered. (Author)
Validation of a model for calculating environmental doses caused by gamma emitters in the soil
International Nuclear Information System (INIS)
Ortega, X.; Rosell, J.R.; Dies, X.
1991-01-01
A model has been developed to calculate the absorbed dose rates caused by gamma emitters of both natural and artificial origin distributed in the soil. The model divides the soil into five compartments corresponding to layers situated at different depths, and assumes that the concentration of radionuclides is constant in each one of them. The calculations, following the model developed, are undertaken through a program which, based on the concentrations of the radionuclides in the different compartments, gives as a result the dose rate at a height of one metre above the ground caused by each radionuclide and the percentage this represents with respect to the total absorbed dose rate originating from this soil. The validity of the model has been checked in the case of sandy soils by comparing the exposure rates calculated for five sites with the experimental values obtained with an ionisation chamber. (author)
Calculation of the gamma-dose rate from a continuously emitted plume
International Nuclear Information System (INIS)
Huebschmann, W.; Papadopoulos, D.
1975-06-01
A computer model is presented which calculates the long term gamma dose rate caused by the radioactive off-gas continuously emitted from a stack. The statistical distribution of the wind direction and velocity and of the stability categories is taken into account. The emitted activity, distributed in the atmosphere according to this statistics, is assumed to be concentrated at the mesh points of a three-dimensional grid. The grid spacing and the integration limits determine the accuracy as well as the computer time needed. When calculating the dose rate in a given wind direction, the contribution of the activity emitted into the neighbouring sectors is evaluated. This influence is demonstrated in the results, which are calculated with a error below 3% and compared to the dose rate distribution curves of the submersion model and the model developed by K.J. Vogt. (orig.) [de
A comparison of the calculation methods of the maze shielding dose
International Nuclear Information System (INIS)
Li Wenqian; Li Junli; Li Pengyu; Tao Yinghua
2009-01-01
This paper gives a theoretical calculating method for the dose rate of the maze of the low-energy accelerators or high-energy accelerators, based on the NCRP report Nos.49, 51 and 151. The multi-legged maze of the Miyun CT workshop of the NUCTECH Company Limited and the arc maze of the radiation laboratory of the Academy of Military Medical Sciences were calculated using this method. The calculating results were compared with the MCNP simulating results and the measured results. For the commonly estimation of the maze dose rate, as long as the parameters chosen properly, this method can give a conservative result, and save time from simulation. It's hoped that this work could offer a reference for the maze design and the dose estimation method in the aftertime. (authors)
DEFF Research Database (Denmark)
Lübeck Christiansen, Rasmus; Jensen, Henrik R.; Brink, Carsten
2017-01-01
Background: Current state of the art radiotherapy planning of prostate cancer utilises magnetic resonance (MR) for soft tissue delineation and computed tomography (CT) to provide an electron density map for dose calculation. This dual scan workflow is prone to setup and registration error....... This study evaluates the feasibility of an MR-only workflow and the validity of dose calculation from an MR derived pseudo CT. Material and methods: Thirty prostate cancer patients were CT and MR scanned. Clinical treatment plans were generated on CT using a single 18 MV arc volumetric modulated arc therapy...... was successfully delivered to one patient, including manually performed daily IGRT. Conclusions: Median gamma pass rates were high for pseudo CT and proved superior to uniform density. Local differences in dose calculations were concluded not to have clinical relevance. Feasibility of the MR-only workflow...
Marrow fat cell: response to x-ray induced aplasia
International Nuclear Information System (INIS)
Bathija, A.; Ohanian, M.; Davis, S.; Trubowitz, S.
1979-01-01
Adipose tissue is an integral structural component of normal rabbit marrow and is believed to behave primarily as a cushion in response to hemopoietic proliferation, accommodating to changes in hemopoiesis by change in either size or number or both of the fat cells in order to maintain constancy of the marrow volume. To test this hypothesis, aplasia of the right femur of New Zealand white rabbits was induced by x irradiation with 8000 rads; the left unirradiated limb served as control. Twenty-four hours before sacrifice 50 μCi of palmitate-114C was administered intravenously and the marrow of both femurs removed. Samples of perinephric fat were taken for comparison. Fat cell volume, C14 palmitate turnover and fatty acid composition were determined. The total number of fat cells in the entire marrow of both femurs was calculated. The measurements showed no difference in size or fatty acid turnover of the fat cells in the irradiated aplastic marrow from the cells of the control marrow. The number of fat cells in both the irradiated and the unirradiated control femurs was essentially the same. These findings do not support the view that marrow fat cells respond to diminished hematopoiesis by either increase in their volume or number. In addition, the findings suggest that both marrow and subcutaneous fat cells are fairly resistant to high doses of x-ray irradiation
Panthere V2: Multipurpose Simulation Software for 3D Dose Rate Calculations
Penessot, Gaël; Bavoil, Éléonore; Wertz, Laurent; Malouch, Fadhel; Visonneau, Thierry; Dubost, Julien
2017-09-01
PANTHERE is a multipurpose radiation protection software developed by EDF to calculate gamma dose rates in complex 3D environments. PANTHERE takes a key role in the EDF ALARA process, enabling to predict dose rates and to organize and optimize operations in high radiation environments. PANTHERE is also used for nuclear waste characterization, transport of nuclear materials, etc. It is used in most of the EDF engineering units and their design service providers and industrial partners.
Li, Jonathan G.; Liu, Chihray; Olivier, Kenneth R.; Dempsey, James F.
2009-01-01
The aim of this study was to investigate the relative accuracy of megavoltage photon‐beam dose calculations employing either five bulk densities or independent voxel densities determined by calibration of the CT Houndsfield number. Full‐resolution CT and bulk density treatment plans were generated for 70 lung or esophageal cancer tumors (66 cases) using a commercial treatment planning system with an adaptive convolution dose calculation algorithm (Pinnacle3, Philips Medicals Systems). Bulk densities were applied to segmented regions. Individual and population average densities were compared to the full‐resolution plan for each case. Monitor units were kept constant and no normalizations were employed. Dose volume histograms (DVH) and dose difference distributions were examined for all cases. The average densities of the segmented air, lung, fat, soft tissue, and bone for the entire set were found to be 0.14, 0.26, 0.89, 1.02, and 1.12 g/cm3, respectively. In all cases, the normal tissue DVH agreed to better than 2% in dose. In 62 of 70 DVHs of the planning target volume (PTV), agreement to better than 3% in dose was observed. Six cases demonstrated emphysema, one with bullous formations and one with a hiatus hernia having a large volume of gas. These required the additional assignment of density to the emphysemic lung and inflammatory changes to the lung, the regions of collapsed lung, the bullous formations, and the hernia gas. Bulk tissue density dose calculation provides an accurate method of heterogeneous dose calculation. However, patients with advanced emphysema may require high‐resolution CT studies for accurate treatment planning. PACS number: 87.53.Tf
Directory of Open Access Journals (Sweden)
Valdis Goncars
2017-01-01
Conclusions: The intra-articular injection of bone marrow-derived mononuclear cells is a safe manipulation with no side effects during the 12-month period. This treatment provides statistically significant clinical improvement between the starting point and 1, 3, 6, and 12 months after. When compared to hyaluronic acid treatment, better pain relief in the long-term period of mononuclear cell group was observed.
Calculation of nuclide inventory, decay power, activity and dose rates for spent nuclear fuel
International Nuclear Information System (INIS)
Haakansson, Rune
2000-03-01
The nuclide inventory was calculated for a BWR and a PWR fuel element, with burnups of 38 and 55 MWd/kg uranium for the BWR fuel, and 42 and 60 MWd/kg uranium for the PWR fuel. The calculations were performed for decay times of up to 300,000 years. Gamma and neutron dose rates have been calculated at a distance of 1 m from a bare fuel element and outside the spent fuel canister. The calculations were performed using the CASMO-4 code
Stratis, Andreas; Zhang, Guozhi; Lopez-Rendon, Xochitl; Politis, Constantinus; Hermans, Robert; Jacobs, Reinhilde; Bogaerts, Ria; Shaheen, Eman; Bosmans, Hilde
2017-09-01
To calculate organ doses and estimate the effective dose for justification purposes in patients undergoing orthognathic treatment planning purposes and temporal bone imaging in dental cone beam CT (CBCT) and Multidetector CT (MDCT) scanners. The radiation dose to the ICRP reference male voxel phantom was calculated for dedicated orthognathic treatment planning acquisitions via Monte Carlo simulations in two dental CBCT scanners, Promax 3D Max (Planmeca, FI) and NewTom VGi evo (QR s.r.l, IT) and in Somatom Definition Flash (Siemens, DE) MDCT scanner. For temporal bone imaging, radiation doses were calculated via MC simulations for a CBCT protocol in NewTom 5G (QR s.r.l, IT) and with the use of a software tool (CT-expo) for Somatom Force (Siemens, DE). All procedures had been optimized at the acceptance tests of the devices. For orthognathic protocols, dental CBCT scanners deliver lower doses compared to MDCT scanners. The estimated effective dose (ED) was 0.32mSv for a normal resolution operation mode in Promax 3D Max, 0.27mSv in VGi-evo and 1.18mSv in the Somatom Definition Flash. For temporal bone protocols, the Somatom Force resulted in an estimated ED of 0.28mSv while for NewTom 5G the ED was 0.31 and 0.22mSv for monolateral and bilateral imaging respectively. Two clinical exams which are carried out with both a CBCT or a MDCT scanner were compared in terms of radiation dose. Dental CBCT scanners deliver lower doses for orthognathic patients whereas for temporal bone procedures the doses were similar. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Dobler, Barbara; Walter, Cornelia; Knopf, Antje; Fabri, Daniella; Loeschel, Rainer; Polednik, Martin; Schneider, Frank; Wenz, Frederik; Lohr, Frank
2006-01-01
The aim of this study was to compare and to validate different dose calculation algorithms for the use in radiation therapy of small lung lesions and to optimize the treatment planning using accurate dose calculation algorithms. A 9-field conformal treatment plan was generated on an inhomogeneous phantom with lung mimics and a soft tissue equivalent insert, mimicking a lung tumor. The dose distribution was calculated with the Pencil Beam and Collapsed Cone algorithms implemented in Masterplan (Nucletron) and the Monte Carlo system XVMC and validated using Gafchromic EBT films. Differences in dose distribution were evaluated. The plans were then optimized by adding segments to the outer shell of the target in order to increase the dose near the interface to the lung. The Pencil Beam algorithm overestimated the dose by up to 15% compared to the measurements. Collapsed Cone and Monte Carlo predicted the dose more accurately with a maximum difference of -8% and -3% respectively compared to the film. Plan optimization by adding small segments to the peripheral parts of the target, creating a 2-step fluence modulation, allowed to increase target coverage and homogeneity as compared to the uncorrected 9 field plan. The use of forward 2-step fluence modulation in radiotherapy of small lung lesions allows the improvement of tumor coverage and dose homogeneity as compared to non-modulated treatment plans and may thus help to increase the local tumor control probability. While the Collapsed Cone algorithm is closer to measurements than the Pencil Beam algorithm, both algorithms are limited at tissue/lung interfaces, leaving Monte-Carlo the most accurate algorithm for dose prediction
Effective Dose Calculation Program (EDCP) for the usage of NORM-added consumer product.
Yoo, Do Hyeon; Lee, Jaekook; Min, Chul Hee
2018-04-09
The aim of this study is to develop the Effective Dose Calculation Program (EDCP) for the usage of Naturally Occurring Radioactive Material (NORM) added consumer products. The EDCP was developed based on a database of effective dose conversion coefficient and the Matrix Laboratory (MATLAB) program to incorporate a Graphic User Interface (GUI) for ease of use. To validate EDCP, the effective dose calculated with EDCP by manually determining the source region by using the GUI and that by using the reference mathematical algorithm were compared for pillow, waist supporter, eye-patch and sleeping mattress. The results show that the annual effective dose calculated with EDCP was almost identical to that calculated using the reference mathematical algorithm in most of the assessment cases. With the assumption of the gamma energy of 1 MeV and activity of 1 MBq, the annual effective doses of pillow, waist supporter, sleeping mattress, and eye-patch determined using the reference algorithm were 3.444 mSv year -1 , 2.770 mSv year -1 , 4.629 mSv year -1 , and 3.567 mSv year -1 , respectively, while those calculated using EDCP were 3.561 mSv year -1 , 2.630 mSv year -1 , 4.740 mSv year -1 , and 3.780 mSv year -1 , respectively. The differences in the annual effective doses were less than 5%, despite the different calculation methods employed. The EDCP can therefore be effectively used for radiation protection management in the context of the usage of NORM-added consumer products. Additionally, EDCP can be used by members of the public through the GUI for various studies in the field of radiation protection, thus facilitating easy access to the program. Copyright © 2018. Published by Elsevier Ltd.
Clinical implementation of full Monte Carlo dose calculation in proton beam therapy
International Nuclear Information System (INIS)
Paganetti, Harald; Jiang, Hongyu; Parodi, Katia; Slopsema, Roelf; Engelsman, Martijn
2008-01-01
The goal of this work was to facilitate the clinical use of Monte Carlo proton dose calculation to support routine treatment planning and delivery. The Monte Carlo code Geant4 was used to simulate the treatment head setup, including a time-dependent simulation of modulator wheels (for broad beam modulation) and magnetic field settings (for beam scanning). Any patient-field-specific setup can be modeled according to the treatment control system of the facility. The code was benchmarked against phantom measurements. Using a simulation of the ionization chamber reading in the treatment head allows the Monte Carlo dose to be specified in absolute units (Gy per ionization chamber reading). Next, the capability of reading CT data information was implemented into the Monte Carlo code to model patient anatomy. To allow time-efficient dose calculation, the standard Geant4 tracking algorithm was modified. Finally, a software link of the Monte Carlo dose engine to the patient database and the commercial planning system was established to allow data exchange, thus completing the implementation of the proton Monte Carlo dose calculation engine ('DoC++'). Monte Carlo re-calculated plans are a valuable tool to revisit decisions in the planning process. Identification of clinically significant differences between Monte Carlo and pencil-beam-based dose calculations may also drive improvements of current pencil-beam methods. As an example, four patients (29 fields in total) with tumors in the head and neck regions were analyzed. Differences between the pencil-beam algorithm and Monte Carlo were identified in particular near the end of range, both due to dose degradation and overall differences in range prediction due to bony anatomy in the beam path. Further, the Monte Carlo reports dose-to-tissue as compared to dose-to-water by the planning system. Our implementation is tailored to a specific Monte Carlo code and the treatment planning system XiO (Computerized Medical Systems Inc
International Nuclear Information System (INIS)
Eged, K.; Kis, Z.; Alvarez-Farizo, B.; Gil, J.; Voigt, G.
2002-01-01
The calculation of the collective dose and averted collective dose after applying countermeasures in an industrial environment has been divided in two parts. In the first part (Kis et al. 2002) separate Monte Carlo simulations of photon transport resulted in the air kermas per photon per unit area due to the industrial surfaces contaminated by 1 37C s at specific points using the so-called local approach. In the local approach the air kerma rates due to specific intervention elements at the evaluation locations in the whole environment are determined (Gutierrez et al. 2000). In this way the collective and averted collective dose due to the radiation from a particular intervention element (e.g. the roof of a building) can be obtained. It can, therefore, provide a ranking of the specific intervention elements based on their contribution to collective dose as well. The deposition pattern and the long-term behaviour of deposited radionuclides vary widely in natural circumstances; therefore the number of the photons emitted from the various surfaces per unit area and time can differ significantly. This means the results of the Monte Carlo simulations have to be weighted according to the number of emitted photons so that the actual radiation field can be set up. For this purpose, a dose calculation code has been developed in the framework of the TEMAS project (Gutierrez et al. 2000) which allows to calculate collective doses for different environments. This code has been applied in the present work
Calculate the maximum expected dose for technical radio physicists a cobalt machine
International Nuclear Information System (INIS)
Avila Avila, Rafael; Perez Velasquez, Reytel; Gonzalez Lapez, Nadia
2009-01-01
Considering the daily operations carried out by technicians Radiophysics Medical Service Department of Radiation Oncology Hospital V. General Teaching I. Lenin in the city of Holguin, during a working week (Between Monday and Friday) as an important element in calculating the maximum expected dose (MDE). From the exponential decay law which is subject the source activity, we propose corrections to the cumulative doses in the weekly period, leading to obtaining a formula which takes into a cumulative dose during working days and sees no dose accumulation of rest days (Saturday and Sunday). The estimate factor correction is made from a power series expansion convergent is truncated at the n-th term coincides with the week period for which you want to calculate the dose. As initial condition is adopted ambient dose equivalent rate as a given, which allows estimate MDE in the moments after or before this. Calculations were proposed use of an Excel spreadsheet that allows simple and accessible processing the formula obtained. (author)
Feasibility of CBCT-based dose calculation: Comparative analysis of HU adjustment techniques
International Nuclear Information System (INIS)
Fotina, Irina; Hopfgartner, Johannes; Stock, Markus; Steininger, Thomas; Lütgendorf-Caucig, Carola; Georg, Dietmar
2012-01-01
Background and purpose: The aim of this work was to compare the accuracy of different HU adjustments for CBCT-based dose calculation. Methods and materials: Dose calculation was performed on CBCT images of 30 patients. In the first two approaches phantom-based (Pha-CC) and population-based (Pop-CC) conversion curves were used. The third method (WAB) represents override of the structures with standard densities for water, air and bone. In ROI mapping approach all structures were overridden with average HUs from planning CT. All techniques were benchmarked to the Pop-CC and CT-based plans by DVH comparison and γ-index analysis. Results: For prostate plans, WAB and ROI mapping compared to Pop-CC showed differences in PTV D median below 2%. The WAB and Pha-CC methods underestimated the bladder dose in IMRT plans. In lung cases PTV coverage was underestimated by Pha-CC method by 2.3% and slightly overestimated by the WAB and ROI techniques. The use of the Pha-CC method for head–neck IMRT plans resulted in difference in PTV coverage up to 5%. Dose calculation with WAB and ROI techniques showed better agreement with pCT than conversion curve-based approaches. Conclusions: Density override techniques provide an accurate alternative to the conversion curve-based methods for dose calculation on CBCT images.
Application of the mathematical modelling and human phantoms for calculation of the organ doses
International Nuclear Information System (INIS)
Kluson, J.; Cechak, T.
2005-01-01
Increasing power of the computers hardware and new versions of the software for the radiation transport simulation and modelling of the complex experimental setups and geometrical arrangement enable to dramatically improve calculation of organ or target volume doses ( dose distributions) in the wide field of medical physics and radiation protection applications. Increase of computers memory and new software features makes it possible to use not only analytical (mathematical) phantoms but also allow constructing the voxel models of human or phantoms with voxels fine enough (e.g. 1·1·1 mm) to represent all required details. CT data can be used for the description of such voxel model geometry .Advanced scoring methods are available in the new software versions. Contribution gives the overview of such new possibilities in the modelling and doses calculations, discusses the simulation/approximation of the dosimetric quantities ( especially dose ) and calculated data interpretation. Some examples of application and demonstrations will be shown, compared and discussed. Present computational tools enables to calculate organ or target volumes doses with new quality of large voxel models/phantoms (including CT based patient specific model ), approximating the human body with high precision. Due to these features has more and more importance and use in the fields of medical and radiological physics, radiation protection, etc. (authors)
International Nuclear Information System (INIS)
Zach, Reto.
1980-07-01
A flexible and interactive code, NEPTUN, has been written in FORTRAN IV for the PDP-10 computer to assess the impact on man of radionuclides in aquatic food chains. NEPTUN is based on an equilibrium model of the linear-chain type, and calculates aquatic food concentrations and doses to man. A decay term is included for the holdup time of the various food types. A total of seven food types can be selected, which include drinking water, freshwater and salt-water plants, inverebrates and fish. Thirty different diets can be implemented and five different dose factor files can be chosen. These include dose conversion factors for infants and adults based on ICRP 2 and ICRP 26 methodologies. All dose factors involve a dose commitment of 50 years, or equivalently, 50 years of chronic exposure. To date, only stochastic ICRP 26 dose caluclations have been implemented. The basic concentration factor file contains data for 211 different radionuclides; the dose factor files are less comprehensive. However, all files can be readily expanded. The output includes tables of concentrations and doses for individual radionuclides, as well as summaries for groups of radionuclides. Existing aquatic food chain models and the sources of currently-used generic concentration factors are briefly reviewed, and dose factors based on ICRP 2 and ICRP 26 methodologies are contrasted. (auth)
The Mayak Worker Dosimetry System (MWDS-2013): implementation of the dose calculations
International Nuclear Information System (INIS)
Zhdanov, A.; Vostrotin, V.; Efimov, A.; Birchall, A.; Puncher, M.
2017-01-01
The calculation of internal doses for the Mayak Worker Dosimetry System (MWDS-2013) involved extensive computational resources due to the complexity and sheer number of calculations required. The required output consisted of a set of 1000 hyper-realizations: each hyper-realization consists of a set (1 for each worker) of probability distributions of organ doses. This report describes the hardware components and computational approaches required to make the calculation tractable. Together with the software, this system is referred to here as the 'PANDORA system'. It is based on a commercial SQL server database in a series of six work stations. A complete run of the entire Mayak worker cohort entailed a huge amount of calculations in PANDORA and due to the relatively slow speed of writing the data into the SQL server, each run took about 47 days. Quality control was monitored by comparing doses calculated in PANDORA with those in a specially modified version of the commercial software 'IMBA Professional Plus'. Suggestions are also made for increasing calculation and storage efficiency for future dosimetry calculations using PANDORA. (authors)
Simplified calculation method for radiation dose under normal condition of transport
International Nuclear Information System (INIS)
Watabe, N.; Ozaki, S.; Sato, K.; Sugahara, A.
1993-01-01
In order to estimate radiation dose during transportation of radioactive materials, the following computer codes are available: RADTRAN, INTERTRAN, J-TRAN. Because these codes consist of functions for estimating doses not only under normal conditions but also in the case of accidents, when nuclei may leak and spread into the environment by air diffusion, the user needs to have special knowledge and experience. In this presentation, we describe how, with a view to preparing a method by which a person in charge of transportation can calculate doses in normal conditions, the main parameters upon which the value of doses depends were extracted and the dose for a unit of transportation was estimated. (J.P.N.)
Energy Technology Data Exchange (ETDEWEB)
Wrede, D E; Dawalibi, H [King Faisal Specialist Hospital and Research Centre, Department of Medical Physics. Riyadh (Saudi Arabia)
1980-01-01
A simple mathematical algorithm is derived from experimental data for dose rates from /sup 137/Cs sources in a finite tissue equivalent medium corresponding to the female pelvis. An analytical expression for a point source of /sup 137/Cs along with a simple numerical integration routine allows for rapid as well as accurate dose rate calculations at points of interest for gynecologic insertions. When compared with theoretical models assuming an infinite unit density medium, the measured dose rates are found to be systematically lower at distances away from a single source; 5 per cent at 2 cm and 10 per cent at 7 cm along the transverse axis. Allowance in the program for print out of dose rates from individual sources to a given point and the feature of source strength modification allows for optimization in terms of increasing the difference in dose rate between reference treatment points and sensitive structures such as the bladder, rectum and colon.
International Nuclear Information System (INIS)
Wrede, D.E.; Dawalibi, H.
1980-01-01
A simple mathematical algorithm is derived from experimental data for dose rates from 137 Cs sources in a finite tissue equivalent medium corresponding to the female pelvis. An analytical expression for a point source of 137 Cs along with a simple numerical integration routine allows for rapid as well as accurate dose rate calculations at points of interest for gynecologic insertions. When compared with theoretical models assuming an infinite unit density medium, the measured dose rates are found to be systematically lower at distances away from a single source; 5 per cent at 2 cm and 10 per cent at 7 cm along the transverse axis. Allowance in the program for print out of dose rates from individual sources to a given point and the feature of source strength modification allows for optimization in terms of increasing the difference in dose rate between reference treatment points and sensitive structures such as the bladder, rectum and colon. (Auth.)
Monte Carlo Calculated Effective Dose to Teenage Girls from Computed Tomography Examinations
International Nuclear Information System (INIS)
Caon, M.; Bibbo, G.; Pattison, J.
2000-01-01
Effective doses from CT to paediatric patients are not common in the literature. This article reports some effective doses to teenage girls from CT examinations. The voxel computational model ADELAIDE, representative of a 14-year-old girl, was scaled in size by ±5% to represent also 11-12-year-old and 16-year-old girls. The EGS4 Monte Carlo code was used to calculate the effective dose from chest, abdomen and whole torso CT examinations to the three version of ADELAIDE using a 120 kV spectrum. For the whole torso CT examination, in order of increasing model size, the effective doses were 9.0, 8.2 and 7.8 mSv per 100 mA.s. Data are presented that allow the estimation of effective dose from CT examinations of the torso for girls between the ages of 11 and 16. (author)
Influence of bone metastases in the red marrow 131INa internal dosimetry
International Nuclear Information System (INIS)
Llina Fuentes, C.S.; Cabrejas, M.I.; Cabrejas, R.
2008-01-01
Full text: This research analyses the evaluation of the absorbed dose in the bone marrow for developing a calculation formalism, based on MIRD methodology, to take into account the influence of bone metastases in patients treated with 131 INa due to thyroid differentiated cancer (DTC). A methodology of image processing is stated for later quantification purposes. The dose contribution, mainly electronic, from trabecular bone and cortical bone to red marrow is considered and a general equation is developed to add that contribution. The biodistribution of active bone marrow in adults bone regions is considered from different studies (Cristy (1981), ICRP 70 (1995), Bouchet et al. (2000), ICRP 89 (2004)). It is assumed that the 60% of red marrow is in the axial skeleton, 25% in ribs, femoral head, proximal portion of chimney and breast bone, and 10% in skull and scapula. Accordingly to this distribution, the bone regions with more percentage are included to calculate the influence in the red marrow absorbed dose. The absorbed dose in bone marrow is calculated considering 4 sources: bone marrow, bone tissue with metastases, rest of the bone tissue without metastases and rest of soft tissue. Conversion factors for fifteen regions of the skeleton, obtained from Eckerman Monte Carlo simulations, were used to calculate absorbed dose in each region of bone. The absorbed dose from this formalism is based on specific biokinetic data from patients and dosimetric models. It was considered of interest to compare the results with the biological dosimetry in parallel. From this biological method, the accumulated absorbed dose from previous therapies and also the bone marrow absorbed dose due to the last radioiodine treatment can be obtained in order to compare dose assessment results between the developed formalism and biological dosimetry. The results obtained with the proposed formalism, show that lesions in some bones regions contribute more to the absorbed dose than lesions in
Preliminary results on food consumption rates for off-site dose calculation of nuclear power plants
International Nuclear Information System (INIS)
Lee, Gab Bock; Chung, Yang Geun; Bang, Sun Young; Kang, Duk Won
2005-01-01
The Internal dose by food consumption mostly account for radiological dose of public around nuclear power plants(NPP). But, food consumption rate applied to off-site dose calculation in Korea which is the result of field investigation around Kori NPP by the KAERI in 1988. is not reflected of the latest dietary characteristics. The Ministry of Health and Welfare Affairs has investigated the food and nutrition of nations every 3 years based on the Law of National Health Improvement. To update the food consumption rates of the maximum individual, the analysis of the national food investigation results and field surveys around nuclear power plant sites have been carried out
Calculations of the photon dose behind concrete shielding of high energy proton accelerators
International Nuclear Information System (INIS)
Dworak, D.; Tesch, K.; Zazula, J.M.
1992-02-01
The photon dose per primary beam proton behind lateral concrete shieldings was calculated by using an extension of the Monte Carlo particle shower code FLUKA. The following photon-producing processes were taken into account: capture of thermal neutrons, deexcitation of nuclei after nuclear evaporation, inelastic neutron scattering and nuclear reactions below 140 MeV, as well as photons from electromagnetic cascades. The obtained ratio of the photon dose to the neutron dose equivalent varies from 8% to 20% and it well compares with measurements performed recently at DESY giving a mean ratio of 14%. (orig.)
SU-E-J-60: Efficient Monte Carlo Dose Calculation On CPU-GPU Heterogeneous Systems
Energy Technology Data Exchange (ETDEWEB)
Xiao, K; Chen, D. Z; Hu, X. S [University of Notre Dame, Notre Dame, IN (United States); Zhou, B [Altera Corp., San Jose, CA (United States)
2014-06-01
Purpose: It is well-known that the performance of GPU-based Monte Carlo dose calculation implementations is bounded by memory bandwidth. One major cause of this bottleneck is the random memory writing patterns in dose deposition, which leads to several memory efficiency issues on GPU such as un-coalesced writing and atomic operations. We propose a new method to alleviate such issues on CPU-GPU heterogeneous systems, which achieves overall performance improvement for Monte Carlo dose calculation. Methods: Dose deposition is to accumulate dose into the voxels of a dose volume along the trajectories of radiation rays. Our idea is to partition this procedure into the following three steps, which are fine-tuned for CPU or GPU: (1) each GPU thread writes dose results with location information to a buffer on GPU memory, which achieves fully-coalesced and atomic-free memory transactions; (2) the dose results in the buffer are transferred to CPU memory; (3) the dose volume is constructed from the dose buffer on CPU. We organize the processing of all radiation rays into streams. Since the steps within a stream use different hardware resources (i.e., GPU, DMA, CPU), we can overlap the execution of these steps for different streams by pipelining. Results: We evaluated our method using a Monte Carlo Convolution Superposition (MCCS) program and tested our implementation for various clinical cases on a heterogeneous system containing an Intel i7 quad-core CPU and an NVIDIA TITAN GPU. Comparing with a straightforward MCCS implementation on the same system (using both CPU and GPU for radiation ray tracing), our method gained 2-5X speedup without losing dose calculation accuracy. Conclusion: The results show that our new method improves the effective memory bandwidth and overall performance for MCCS on the CPU-GPU systems. Our proposed method can also be applied to accelerate other Monte Carlo dose calculation approaches. This research was supported in part by NSF under Grants CCF
Oliveira, C
2001-01-01
A systematic study of isodose distributions and dose uniformity in sample carriers of the Portuguese Gamma Irradiation Facility was carried out using the MCNP code. The absorbed dose rate, gamma flux per energy interval and average gamma energy were calculated. For comparison purposes, boxes filled with air and 'dummy' boxes loaded with layers of folded and crumpled newspapers to achieve a given value of density were used. The magnitude of various contributions to the total photon spectra, including source-dependent factors, irradiator structures, sample material and other origins were also calculated.
Applying graphics processor units to Monte Carlo dose calculation in radiation therapy
Directory of Open Access Journals (Sweden)
Bakhtiari M
2010-01-01
Full Text Available We investigate the potential in using of using a graphics processor unit (GPU for Monte-Carlo (MC-based radiation dose calculations. The percent depth dose (PDD of photons in a medium with known absorption and scattering coefficients is computed using a MC simulation running on both a standard CPU and a GPU. We demonstrate that the GPU′s capability for massive parallel processing provides a significant acceleration in the MC calculation, and offers a significant advantage for distributed stochastic simulations on a single computer. Harnessing this potential of GPUs will help in the early adoption of MC for routine planning in a clinical environment.
Calculation of doses of fast electrons in formation of the beam with the aid of grids
Energy Technology Data Exchange (ETDEWEB)
Kozlov, A P; Telesh, L V; Chifonenko, V V; Shishov, V A
1976-04-01
The authors describe the method of finding dose distributions of electron beams formed with the aid of grids. Calculation of fields for different grids is made with the help of the mentioned method. The authors analyzed the relation between the depth of location, extension of the homogeneous area, and the engagement factor and size of the grid holes. The effect of electron scattering on the hole edges on the shape of the dose field is considered. The comparison of calculated and experimental results shows that the method is sufficiently accurate to be used for practical radiation therapy.
A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.
Nwankwo, Obioma; Glatting, Gerhard; Wenz, Frederik; Fleckenstein, Jens
2017-01-01
To introduce a new method of deriving a virtual source model (VSM) of a linear accelerator photon beam from a phase space file (PSF) for Monte Carlo (MC) dose calculation. A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs) for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC) between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses. The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate) for the evaluated fields. A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.
A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.
Directory of Open Access Journals (Sweden)
Obioma Nwankwo
Full Text Available To introduce a new method of deriving a virtual source model (VSM of a linear accelerator photon beam from a phase space file (PSF for Monte Carlo (MC dose calculation.A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses.The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate for the evaluated fields.A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.
Improved Patient Size Estimates for Accurate Dose Calculations in Abdomen Computed Tomography
Energy Technology Data Exchange (ETDEWEB)
Lee, Chang-Lae [Yonsei University, Wonju (Korea, Republic of)
2017-07-15
Th