Assessment of CT dose to the fetus and pregnant female patient using patient-specific computational models

DEFF Research Database (Denmark)

Xie, Tianwu; Poletti, Pierre-Alexandre; Platon, Alexandra

2018-01-01

of pregnant patients and the embedded foetus, we developed a methodology for construction of patient-specific voxel-based computational phantoms based on existing standardised hybrid computational pregnant female phantoms. We estimated the maternal absorbed dose and foetal organ dose for 30 pregnant patients...... for assessment of the radiation risks to pregnant patients and the foetus from various CT scanning protocols, thus guiding the decision-making process. KEY POINTS: • In CT examinations, the absorbed dose is non-uniformly distributed within foetal organs. • This work reports, for the first time, estimates...

Assessment of CT dose to the fetus and pregnant female patient using patient-specific computational models

Energy Technology Data Exchange (ETDEWEB)

Xie, Tianwu; Poletti, Pierre-Alexandre; Platon, Alexandra; Becker, Christoph D. [Geneva University Hospital, Department of Medical Imaging and Information Sciences, Geneva (Switzerland); Zaidi, Habib [Geneva University Hospital, Department of Medical Imaging and Information Sciences, Geneva (Switzerland); Geneva University, Geneva Neuroscience Center, Geneva (Switzerland); University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, University of Groningen, Groningen (Netherlands); University of Southern Denmark, Department of Nuclear Medicine, Odense (Denmark); Geneva University Hospital, Division of Nuclear Medicine and Molecular Imaging, Geneva (Switzerland)

2018-03-15

This work provides detailed estimates of the foetal dose from diagnostic CT imaging of pregnant patients to enable the assessment of the diagnostic benefits considering the associated radiation risks. To produce realistic biological and physical representations of pregnant patients and the embedded foetus, we developed a methodology for construction of patient-specific voxel-based computational phantoms based on existing standardised hybrid computational pregnant female phantoms. We estimated the maternal absorbed dose and foetal organ dose for 30 pregnant patients referred to the emergency unit of Geneva University Hospital for abdominal CT scans. The effective dose to the mother varied from 1.1 mSv to 2.0 mSv with an average of 1.6 mSv, while commercial dose-tracking software reported an average effective dose of 1.9 mSv (range 1.7-2.3 mSv). The foetal dose normalised to CTDI{sub vol} varies between 0.85 and 1.63 with an average of 1.17. The methodology for construction of personalised computational models can be exploited to estimate the patient-specific radiation dose from CT imaging procedures. Likewise, the dosimetric data can be used for assessment of the radiation risks to pregnant patients and the foetus from various CT scanning protocols, thus guiding the decision-making process. (orig.)

MRI of the foetal brain

International Nuclear Information System (INIS)

Rich, P.; Jones, R.; Britton, J.; Foote, S.; Thilaganathan, B.

2007-01-01

Ultrasound examinations for foetal brain abnormalities have been a part of the routine antenatal screening programme in the UK for many years. In utero brain magnetic resonance imaging (MRI) is now being used increasingly successfully to clarify abnormal ultrasound findings, often resulting in a change of diagnosis or treatment plan. Interpretation requires an understanding of foetal brain development, malformations and acquired diseases. In this paper we will outline the technique of foetal MRI, relevant aspects of brain development and provide illustrated examples of foetal brain pathology

ASSESSMENT OF FOETAL COMPROMISE BY DOPPLER ULTRASOUND INVESTIGATION OF THE FOETAL CIRCULATION

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Bindu Philip

2017-09-01

Full Text Available BACKGROUND The condition in which the foetus does not reach its growth potential is called Intrauterine Growth Restricted (IUGR. The mothers who are generally healthy and well nourished, the incidence of IUGR is 3-5%. The incidence of IUGR is 15-20% or higher in a women population with hypertension or previous growth restricted foetus. The aim of the study is to assess foetal compromise by Doppler ultrasound investigation of the foetal circulation. MATERIALS AND METHODS This study is a prospective study conducted between November 2013 to November 2016 in the Department of Radiodiagnosis and imaging of Mount Zion Medical College, Kerala. A total of 50 singleton pregnancies with suspected IUGR pregnancy attending the outpatient ward of Obstetrics and Gynaecology. Inclusion Criteria- Pregnancies from 29 weeks to 42 weeks of gestation complicated by intrauterine growth restriction and who are ultrasound confirmed. In the first trimester, gestational age determination was estimated by history of menstruation or biometry of foetus. Exclusion Criteria- Patients who had multiple gestations, congenital anomalies and history of membranes rupture. All the patients in the study were subjected to clinical history in detail to assess the risk factors of IUGR pregnancy, biometry of ultrasound and amniotic fluid assessment followed by Doppler ultrasound evaluation of uterine arteries, umbilical artery, middle cerebral artery, descending foetal thoracic aorta, ductus venous and umbilical vein. RESULTS Majority of the patients were in the age group of 21-24 years. All the patients were in the age group of 19-30 years. 45% of antenatal mothers examined were between 28-31 weeks of gestational age, 35% were between 32-36 weeks of gestation, 20% were between 37-42 weeks of gestation age. 15 antenatal mothers had elevated uterine artery resistance index (30%, 12 antenatal mothers had persistent early diagnostic notch (24%, 11 antenatal mothers had elevated systolic

INFLUENCE OF AMNIOTIC FLUID INDEX ON FOETAL OUTCOME

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Raja Lakshmi

2015-03-01

Full Text Available BACKGROUND AND OBJECTIVE: In these days of smaller families and the obstetrician having to share the onus of giving a healthy child capable of independent existence as well as to ensure that the population is limited for further progress of this developing country, the estimation o f foetal maturity assumes greatest practical importance. As means to achieving the end, estimates of foetal maturity have been done by various clinical and laboratory methods of which assessment of amniotic fluid index assumes importance. The objective is to study the correlation of amniotic fluid index on foetal outcome at term gestation . MATERIALS AND METHODS: The study was carried out on two hundred antenatal women who attended the institute of obstetrics and gynaecology at a Government Hospital for Wome n and Children in Visakhapatnam from Jan 2014 to Jan 2015. It is a comparative prospective study comparing 100 cases of Oligohydramnios (amniotic fluid index 5 cm as control group. RESU LTS : Perinatal outcome was inferred by noting the various parameters and Statistical Analysis was done by applying the chisquare (x2 test and the value of probability was taken . CONCLUSION: The goal of antepartum fetal surveillance is to identify the fetu s at increased risk. Amniotic fluid volume has been proved as an indirect measure of feto - placental function and hence the estimation of amniotic fluid volume assists the obstetrician in risk assessment

Foetal response to music and voice.

Science.gov (United States)

Al-Qahtani, Noura H

2005-10-01

To examine whether prenatal exposure to music and voice alters foetal behaviour and whether foetal response to music differs from human voice. A prospective observational study was conducted in 20 normal term pregnant mothers. Ten foetuses were exposed to music and voice for 15 s at different sound pressure levels to find out the optimal setting for the auditory stimulation. Music, voice and sham were played to another 10 foetuses via a headphone on the maternal abdomen. The sound pressure level was 105 db and 94 db for music and voice, respectively. Computerised assessment of foetal heart rate and activity were recorded. 90 actocardiograms were obtained for the whole group. One way anova followed by posthoc (Student-Newman-Keuls method) analysis was used to find if there is significant difference in foetal response to music and voice versus sham. Foetuses responded with heart rate acceleration and motor response to both music and voice. This was statistically significant compared to sham. There was no significant difference between the foetal heart rate acceleration to music and voice. Prenatal exposure to music and voice alters the foetal behaviour. No difference was detected in foetal response to music and voice.

Estimation of the fetal dose by dose measurement during an irradiation of a parotid tumor; Estimation de la dose foetale par mesure de dose lors d'une irradiation d'une tumeur de la parotide

Energy Technology Data Exchange (ETDEWEB)

Marchesi, V.; Graff-Cailleaud, P.; Peiffert, D. [Centre Alexis-Vautrin, 54 - Vandoeuvre-les-Nancy (France); Noel, A. [Institut National Polytechnique de Lorraine, CRAN CNRS UMR-7039, 54 - Vandoeuvre-les-Nancy (France)

2006-11-15

The irradiation of a five months pregnant patient has been made for a right parotid attack. In conformation with the legislative texts relative to radiation protection ( publication 84 of the ICRP) an estimation of the dose received for the fetus has been led by dose measurement on phantom. With the dose limit ( 100 mGy) recommended in the publication 84 of the ICRP neither modification of the treatment nor abortion was necessary. (N.C.)

Foetal dosimetry--is the ICRP dosimetric system for humans now complete?

Energy Technology Data Exchange (ETDEWEB)

Jones, Steve [Westlakes Research Institute, Cumbria (United Kingdom)

2002-03-01

Internal dosimetry is possibly the most complex area of science associated with radiological protection, and has a long history. Primary control of internal exposure now relied on control of annual intakes rather than limitation of organ burdens. Although it took nearly a decade for regulations and hence the practice of occupational radiation protection to fully adopt the new recommendations, the new dosimetric concepts were quite rapidly adopted in the assessment of public exposure because the new methods provided a more natural means of assessing the significance of exposure to a combination of external and internal exposure involving a number of different radionuclides. As a result, following the ICRP's initial publication of dosimetric models for occupational exposure, adaptations became available to cover environmental exposure, including the exposure of infants and children. Increasingly sophisticated biokinetic and dosimetric models have now been developed which, together with the welcome availability of dose per unit intake factors in CD-ROM form make it easy for the radiation protection practitioner to assess committed effective doses, and committed equivalent doses to individual organs, to occupationally exposed adults and environmentally exposed infants, children and adults. The inability to readily assess doses to the developing foetus has, however, long been perceived as a significant gap in knowledge with implications for the study of childhood leukaemia in the vicinity of nuclear installations and possibly also the control of occupational exposure for women of child-bearing age. The first systematic assessment of doses to the foetus was in connection with the study of childhood leukaemia in the vicinity of Sellafield in the UK, for which preliminary models were developed. Since that time a few publications giving guidance on the calculation of foetal doses have emerged and more sophisticated assessments of foetal dose have been reported

Subsequent pregnancy outcome after previous foetal death

NARCIS (Netherlands)

Nijkamp, J. W.; Korteweg, F. J.; Holm, J. P.; Timmer, A.; Erwich, J. J. H. M.; van Pampus, M. G.

Objective: A history of foetal death is a risk factor for complications and foetal death in subsequent pregnancies as most previous risk factors remain present and an underlying cause of death may recur. The purpose of this study was to evaluate subsequent pregnancy outcome after foetal death and to

Foetal and neonatal alloimmune thrombocytopaenia

Directory of Open Access Journals (Sweden)

Kaplan Cecile

2006-10-01

Full Text Available Abstract Foetal/neonatal alloimmune thrombocytopaenia (NAIT results from maternal alloimmunisation against foetal platelet antigens inherited from the father and different from those present in the mother, and usually presents as a severe isolated thrombocytopaenia in otherwise healthy newborns. The incidence has been estimated at 1/800 to 1/1 000 live births. NAIT has been considered to be the platelet counterpart of Rh Haemolytic Disease of the Newborn (RHD. Unlike RHD, NAIT can occur during a first pregnancy. The spectrum of the disease may range from sub-clinical moderate thrombocytopaenia to life-threatening bleeding in the neonatal period. Mildly affected infants may be asymptomatic. In those with severe thrombocytopaenia, the most common presentations are petechiae, purpura or cephalohaematoma at birth, associated with major risk of intracranial haemorrhage (up to 20% of reported cases, which leads to death or neurological sequelae. Alloimmune thrombocytopaenia is more often unexpected and is usually diagnosed after birth. Once suspected, the diagnosis is confirmed by demonstration of maternal antiplatelet alloantibodies directed against a paternal antigen inherited by the foetus/neonate. Post-natal management involves transfusion of platelets devoid of this antigen, and should not be delayed by biological confirmation of the diagnosis (once the diagnosis is suspected, especially in case of severe thrombocytopaenia. Prompt diagnosis and treatment are essential to reduce the chances of death and disability due to haemorrhage. Due to the high rate of recurrence and increased severity of the foetal thrombocytopaenia in successive pregnancies, antenatal therapy should be offered. However, management of high-risk pregnancies is still a matter of discussion.

PREDICTIVE ACCURACY OF TRANSCEREBELLAR DIAMETER IN COMPARISON WITH OTHER FOETAL BIOMETRIC PARAMETERS FOR GESTATIONAL AGE ESTIMATION AMONG PREGNANT NIGERIAN WOMEN.

Science.gov (United States)

Adeyekun, A A; Orji, M O

2014-04-01

To compare the predictive accuracy of foetal trans-cerebellar diameter (TCD) with those of other biometric parameters in the estimation of gestational age (GA). A cross-sectional study. The University of Benin Teaching Hospital, Nigeria. Four hundred and fifty healthy singleton pregnant women, between 14-42 weeks gestation. Trans-cerebellar diameter (TCD), biparietal diameter (BPD), femur length (FL), abdominal circumference (AC) values across the gestational age range studied. Correlation and predictive values of TCD compared to those of other biometric parameters. The range of values for TCD was 11.9 - 59.7mm (mean = 34.2 ± 14.1mm). TCD correlated more significantly with menstrual age compared with other biometric parameters (r = 0.984, p = 0.000). TCD had a higher predictive accuracy of 96.9% ± 12 days), BPD (93.8% ± 14.1 days). AC (92.7% ± 15.3 days). TCD has a stronger predictive accuracy for gestational age compared to other routinely used foetal biometric parameters among Nigerian Africans.

Smoking, physical exercise, BMI and late foetal death: a study within the Danish National Birth Cohort.

Science.gov (United States)

Morales-Suárez-Varela, Maria; Nohr, Ellen A; Bech, Bodil H; Wu, Chunsen; Olsen, Jørn

2016-10-01

The aim of this paper was to estimate the effect of maternal and paternal smoking on foetal death (miscarriage and stillbirth) and to estimate potential interactions with physical exercise and pre-pregnancy body mass index. We selected 87,930 pregnancies from the population-based Danish National Birth Cohort. Information about lifestyle, occupational, medical and obstetric factors was obtained from a telephone interview and data on pregnancy outcomes came from the Danish population based registries. Cox regression was used to estimate the hazard ratios (adjusted for potential confounders) for predominantly late foetal death (miscarriage and stillbirth). An interaction contrast ratio was used to assess potential effect measure modification of smoking by physical exercise and body mass index. The adjusted hazard ratio of foetal death was 1.22 (95 % CI 1.02-1.46) for couples where both parents smoked compared to non-smoking parents (miscarriage: 1.18, 95 % CI 0.96-1.44; stillbirth: 1.32, 95 % CI 0.93-1.89). On the additive scale, we detected a small positive interaction for stillbirth between smoking and body mass index (overweight women). In conclusion, smoking during pregnancy was associated with a slightly higher hazard ratio for foetal death if both parents smoked. This study suggests that smoking may increase the negative effect of a high BMI on foetal death, but results were not statistically significant for the interaction between smoking and physical exercise.

Changes in foetal liver T2* measurements by MRI in response to maternal oxygen breathing: application to diagnosing foetal growth restriction

International Nuclear Information System (INIS)

Morris, David M; Semple, Scott IK; Gilbert, Fiona J; Redpath, Thomas W; Ross, John AS; McVicar, Alexandra; Haggarty, Paul; Abramovich, David R; Smith, Norman

2010-01-01

The motivation of the project was to investigate the use of oxygen-challenge magnetic resonance imaging (OC-MRI) as a method of diagnosing foetal growth restriction. Foetal growth restriction is associated with restricted foetal oxygen supply and is also associated with increased risks of perinatal mortality and morbidity, and a number of serious and chronic health problems. Measurements of T2* relaxation time, an MRI parameter which increases with blood oxygenation, were made in the right lobe of the foetal liver in 80 singleton pregnancies, before and after the mother breathed oxygen. The groups consisted of 41 foetuses with normal growth and 39 with apparent growth restriction. The mean ± SD gestational age at scanning was 35 ± 3 weeks. Changes in foetal liver T2* on maternal oxygen breathing showed no significant difference between the groups therefore the OC-MRI protocol used in this study has no value in the diagnosis of foetal growth restriction. A secondary finding was that a significant positive correlation of T2* change with gestational age was observed. Future studies on the use of oxygen-challenge MRI to investigate foetal growth restriction may therefore need to control for gestational age at the time of MR scanning in order to observe any underlying foetal growth-related effects

Contribution to the study of embryo-foetal risks due to radiodiagnosis

International Nuclear Information System (INIS)

Vibert, M.-R.

1976-01-01

During the last few years appreciable numbers of women have undergone pelvic irradiations for diagnostic reasons at the start of an unsuspected pregnancy. In such cases opinions on the danger of radiations are often extremely divergent: - for some authors no danger exists at the doses used for radiodiagnosis and the pregnancy need never be terminated; - for others on the contrary the risk of malformation is not negligible and should lead to systematic therapeutic abortion. These over-categorically opposed attitudes motivated the present work. The aim is to estimate the embryo-foetal risks, especially as a function of the radiation dose given by dosimetry, but also to warm radiologists of the harm they may cause to a foetus when they irradiate the pelvis of a women of child-bearing age without accounting for the date of her latest period, hence a possible pregnancy. The conclusions to emerge from this work should always be interpreted with two important facts in mind: - One concerns the evaluation of irradiation. Dosimetry is not an exact measurement but only an indication, often underestimated, of the dose actually received and since the existence of a threshold dose has not been proved this evaluation must be considered with caution. - The other concerns the effect of this irradiation on the unborn child, about which little is known [fr

A lymphoblastoid response of human foetal lymphocytes to ultraviolet-irradiated herpes simplex virus

International Nuclear Information System (INIS)

Westmoreland, D.

1980-01-01

Cultures of foetal lymphocytes were exposed to u.v.-irradiated herpes simplex virus (HSV). The cells responded with increased 6- 3 H-thymidine incorporation, the formation of clumps of enlarged lymphoblastoid cells and cell division. This response was first detected 3 to 4 days after exposure to virus material and was shown to be virus-dose dependent. The ability to stimulate foetal cells was considerably more u.v. resistant than infectivity. Two isolates of HSV type 2 (4663 and 37174), which had a high 'transforming' ability, produced large numbers of non-infectious particles (particle: infectivity ratios in excess of 10 4 ). The cells, which responded to u.v.-irradiated HSV with blastoid transformation, were associated with the non-E-rosetting (T-cell-depleted) subpopulation. (author)

Effect of maternal hypoglycaemia during gestation on materno-foetal nutrient transfer and embryo-foetal development

DEFF Research Database (Denmark)

Jensen, Vivi F.H.; Mølck, Anne Marie; Lykkesfeldt, Jens

2018-01-01

of the chorio-allantoic placental circulation. Maternal hypoglycaemia is accompanied by foetal hypoglycaemia and maternal counter-regulatory measures including a priority to keep nutrients in the maternal circulation by restricting their transfer to the foetus. Concomitantly, the foetus initiates its own...... counter-regulatory attempt to secure nutrients for its development and survival. Despite these measures, there is a general decrease in nutrient transfer to the foetus, which may have severe consequences for foetal development such as malformations and delayed skeletal development....

Concentration of perfluorinated compounds and cotinine in human foetal organs, placenta, and maternal plasma

DEFF Research Database (Denmark)

Mamsen, Linn Salto; Jönsson, Bo A.G.; Lindh, Christian H.

2017-01-01

levels. Foetal exposure has previously been estimated from umbilical cord plasma, but the actual concentration in foetal organs has never been measured. Objectives The concentrations of 5 PFASs and cotinine – the primary metabolite of nicotine – were measured in human foetuses, placentas, and maternal...... plasma to evaluate to what extent these compounds were transferred from mother to foetus and to determine if the PFAS concentrations were associated with maternal cigarette smoking. Methods Thirty-nine Danish women who underwent legal termination of pregnancy before gestational week 12 were included; 24...... ratio for all five PFASs and cotinine. Smokers presented 99 ng/g cotinine in plasma, 108 ng/g in placenta, and 61 ng/g in foetal organs. No correlation between the maternal cotinine concentrations and PFAS concentrations was found. Conclusions PFASs were transferred from mother to foetus, however...

Foetal immune programming: hormones, cytokines, microbes and regulatory T cells.

Science.gov (United States)

Hsu, Peter; Nanan, Ralph

2014-10-01

In addition to genetic factors, environmental cues play important roles in shaping the immune system. The first environment that the developing foetal immune system encounters is the uterus. Although physically the mother and the foetus are separated by the placental membranes, various factors such as hormones and cytokines may provide "environmental cues" to the foetal immune system. Additionally, increasing evidence suggests that prenatal maternal environmental factors, particularly microbial exposure, might significantly influence the foetal immune system, affecting long-term outcomes, a concept termed foetal immune programming. Here we discuss the potential mediators of foetal immune programming, focusing on the role of pregnancy-related hormones, cytokines and regulatory T cells, which play a critical role in immune tolerance. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A foetal tile from an archaeological site: anthropological investigation of human remains recovered in a medieval cemetery in Northern Italy.

Science.gov (United States)

Licata, Marta; Rossetti, Chiara; Tosi, Adelaide; Badino, Paola

2018-06-01

The recovery of foetal remains is very sporadic in archaeology, especially due the scarce degree of bone mineralisation. This paper presents the singular archaeological discovery of a foetal tile preserving the bone remains, object of our anthropological examination. The foetal tile was discovered during an archaeological excavation in a medieval site (Northern Italy). The tile was analysed by CT scan and later, human remains were anthropologically examined. The archaeological investigation revealed a special ritual destined to foetuses while forensic anthropological analysis allowed estimating the gestational age near to 21-24 weeks.

Laterality of foetal self-touch in relation to maternal stress.

Science.gov (United States)

Reissland, Nadja; Aydin, Ezra; Francis, Brian; Exley, Kendra

2015-01-01

This longitudinal observational study investigated whether foetuses change their hand preference with gestational age, and also examined the effects of maternal stress on lateralized foetal self-touch. Following ethical approval, fifteen healthy foetuses (eight girls and seven boys) were scanned four times from 24 to 36 weeks gestation. Self-touch behaviours which resulted in a touch of the foetal face/head were coded in 60 scans for 10 min and analysed in terms of frequency of the foetuses using left and right hands to touch their face. The joint effects of foetal age, stress and sex on laterality were assessed. We modelled the proportion of right self-touches for each foetal scan using a generalized linear mixed model, taking account of the repeated measures design. There was substantial variability in hand preference between foetuses. However, there was no significant increase in the proportion of right-handed touches with foetal age. No sex differences in handedness were identified. However, maternally reported stress level was significantly positively related to foetal left-handed self-touches (odds ratio 0.915; p < .0001). This longitudinal study provides important new insights into the effect of recent maternal stress on foetal predominant hand use during self-touch.

[Risks factors associated with intra-partum foetal mortality in pre-term infants].

Science.gov (United States)

Zeballos Sarrato, Susana; Villar Castro, Sonia; Ramos Navarro, Cristina; Zeballos Sarrato, Gonzalo; Sánchez Luna, Manuel

2017-03-01

Pre-term delivery is one of the leading causes of foetal and perinatal mortality. However, perinatal risk factors associated with intra-partum foetal death in preterm deliveries have not been well studied. To analyse foetal mortality and perinatal risk factors associated with intra-partum foetal mortality in pregnancies of less than 32 weeks gestational age. The study included all preterm deliveries between 22 and 31 +1 weeks gestational age (WGA), born in a tertiary-referral hospital, over a period of 7 years (2008-2014). A logistic regression model was used to identify perinatal risk factors associated with intra-partum foetal mortality (foetal malformations and chromosomal abnormalities were excluded). During the study period, the overall foetal mortality was 63.1% (106/168) (≥22 weeks of gestation) occurred in pregnancies of less than 32 WGA. A total of 882 deliveries between 22 and 31+6 weeks of gestation were included for analysis. The rate of foetal mortality was 11.3% (100/882). The rate of intra-partum foetal death was 2.6% (23/882), with 78.2% (18/23) of these cases occurring in hospitalised pregnancies. It was found that Assisted Reproductive Techniques, abnormal foetal ultrasound, no administration of antenatal steroids, lower gestational age, and small for gestational age, were independent risk factors associated with intra-partum foetal mortality. This study showed that there is a significant percentage intra-partum foetal mortality in infants between 22 and 31+6 WGA. The analysis of intrapartum mortality and risk factors associated with this mortality is of clinical and epidemiological interest to optimise perinatal care and improve survival of preterm infants. Copyright © 2016 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

Antenatal diagnosis and management of foetal intestinal volvulus.

Science.gov (United States)

Yip, K W; Cheng, Y K Y; Leung, T Y

2017-04-01

In-utero intestinal volvulus is a rare but potential life threatening foetal complications. It is a surgical emergency and delay in diagnosis or treatment can increase the morbidity and mortality to the foetus. We report a case of mild foetal bowel dilatation diagnosed at 21 weeks of gestation. She was closely follow up and at 31 weeks of gestation, in-utero intestinal volvulus was diagnosed with the characteristic 'whirlpool' sign on ultrasound examination. This case emphasises the importance of early recognition and quick decision to delivery when intestinal volvulus is diagnosed. This enabled early surgical intervention to prevent further foetal morbidity.

Foetal radiography for suspected skeletal dysplasia: technique, normal appearances, diagnostic approach

Energy Technology Data Exchange (ETDEWEB)

Calder, Alistair D. [Great Ormond Street Hospital for Children NHS Foundation Trust, Radiology Department, London (United Kingdom); Offiah, Amaka C. [Sheffield Children' s NHS Foundation Trust, Academic Unit of Child Health, Sheffield (United Kingdom)

2015-04-01

Despite advances in antenatal imaging and genetic techniques, post-delivery post-mortem foetal radiography remains the key investigation in accurate diagnosis of skeletal dysplasia manifesting in the foetus. Foetal radiography is best performed using pathology-specimen radiography equipment and is often carried out in the pathology department without involvement of the radiology unit. However, paediatric radiologists may be asked to interpret post-mortem foetal radiographs when an abnormality is suspected. Many foetal radiographs are carried out before 20 weeks' gestation, and the interpreting radiologist needs to be familiar with the range of normal post-mortem foetal appearances at different gestational ages, as well as the appearances of some of the more commonly presenting skeletal dysplasias, and will benefit from a systematic approach when assessing more challenging cases. In this pictorial essay, we illustrate various normal post-mortem foetal radiographic appearances, give examples of commonly occurring skeletal dysplasias, and describe an approach to establishing more difficult diagnoses. (orig.)

Foetal radiography for suspected skeletal dysplasia: technique, normal appearances, diagnostic approach

International Nuclear Information System (INIS)

Calder, Alistair D.; Offiah, Amaka C.

2015-01-01

Despite advances in antenatal imaging and genetic techniques, post-delivery post-mortem foetal radiography remains the key investigation in accurate diagnosis of skeletal dysplasia manifesting in the foetus. Foetal radiography is best performed using pathology-specimen radiography equipment and is often carried out in the pathology department without involvement of the radiology unit. However, paediatric radiologists may be asked to interpret post-mortem foetal radiographs when an abnormality is suspected. Many foetal radiographs are carried out before 20 weeks' gestation, and the interpreting radiologist needs to be familiar with the range of normal post-mortem foetal appearances at different gestational ages, as well as the appearances of some of the more commonly presenting skeletal dysplasias, and will benefit from a systematic approach when assessing more challenging cases. In this pictorial essay, we illustrate various normal post-mortem foetal radiographic appearances, give examples of commonly occurring skeletal dysplasias, and describe an approach to establishing more difficult diagnoses. (orig.)

Optimisation and evaluation of the foetal dose during a radiotherapy of the right parotid; Optimisation et evaluation de la dose foetale pendant une radiotherapie de la parotide droite

Energy Technology Data Exchange (ETDEWEB)

Marchesi, V.; Noel, A. [Centre Alexis-Vautrin, Unite de Radiophysique Medicale, 54 - Vandoeuvre-les-Nancy (France); Graff, P.; Beckendorf, V.; Peiffert, D. [Centre Alexis-Vautrin, Dept. de Radiotherapie, 54 - Vandoeuvre-les-Nancy (France); Noel, A. [Institut National Polytechnique de Lorraine, CRAN, CNRS UMR-7039, 54 - Vandoeuvre-les-Nancy (France)

2008-09-15

Purpose was to optimize and to estimate the dose delivered to the foetus during a postoperative irradiation of a 5-month twin pregnant woman presenting with adenocarcinoma of the right parotid. The treatment protocol aimed to deliver 66 Gy conformal radiation therapy on the tumour bed associated to a prophylactic irradiation of 50 Gy on the upper cervical nodes. A series of measurements allowed to estimate the delivered dose in the abdomen by the means of an ion chamber inserted in a water phantom placed side by side of an anthropomorphic Alderson Rando phantom simulating the body of the patient from the head to the pelvis. An appropriate optimisation of the number and orientation of beams were performed in order to minimize the peripheral dose, which is mostly dependent of the total number of monitor unit per fraction: cervical nodes and tumour site included in the same fields, limitation of the irradiated volume, 6 MV X-ray beams rather than Cobalt beams. The measured doses at the upper, in the middle and at the lower part of the abdomen were 17.0, 11.0 and 11.9 mGy, respectively, for the entire treatment, representing 0.025, 0.016 and 0.017%, respectively of the prescribed dose. The actions conducted to optimise the treatment allowed to lower doses delivered to the foetus under the limits proposed by international recommendations (100 mGy). Thus, the treatment of the pregnant patient had been performed with a minimized risk for the foetus. (authors)

Apple-peel atresia presenting as foetal intestinal obstruction ...

African Journals Online (AJOL)

Apple-peel atresia or Type 3 jejuno-ileal atresia (JIA) is an uncommon cause of foetal intestinal obstruction. Bowel obstruction in the foetus is diagnosed on the prenatal ultrasonography only in 50% cases. We report a case in which foetal intestinal obstruction was diagnosed on prenatal ultrasonography. The child showed ...

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

Science.gov (United States)

Iriuchijima, Akiko; Fukushima, Yasuhiro; Ogura, Akio

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

Estimated fluence-to-absorbed dose conversion coefficients for use in radiological protection of embryo and foetus against external exposure to photons from 50 keV to 10 GeV

International Nuclear Information System (INIS)

Chen, J.

2006-01-01

In the literature, no conversion coefficients are available for use in radiological protection of the embryo and foetus against external exposure to photons. This study used the Monte-Carlo code MCNPX to determine mean absorbed doses to the embryo and foetus when the mother is exposed to external photon fields. Monoenergetic photons ranging from 50 keV to 10 GeV were considered. The irradiation geometries included antero-posterior (AP), postero-anterior (PA), lateral (LAT), rotational (ROT), and isotropic (ISO). At each of these standard irradiation geometries, absorbed doses to the foetal brain and body were calculated for the embryo of 8 weeks and the foetus of 3, 6 or 9 months. Photon fluence-to-absorbed-dose conversion coefficients were estimated for the four prenatal ages. (authors)

Prolonged Intrauterine Retention of Foetal Bones after Midtrimester ...

African Journals Online (AJOL)

Prolonged retention of foetal bones in the uterus is a rare complication of induced abortion. We present the case of a 37 year old nullipara with retained foetal bones following a second trimester induced abortion. Accurate diagnosis and removal of the bony fragments led to restoration of fertility and subsequent delivery of a ...

NON-INVASIVE MONITORING OF FOETAL ANAEMIA IN KELL SENSITIZED PREGNANCY.

Science.gov (United States)

Memon, Zaibunnisa; Sheikh, Sana Sadiq

2015-01-01

We report a case of Kell sensitized pregnancy with good neonatal outcome. Anti-K antibodies were detected in maternal serum in early pregnancy as a part of routine antibody screening test. The middle cerebral artery doppler monitoring and serial titers were carried out to screen for foetal anaemia. Despite of rising antibody titers, serial middle cerebral artery doppler was normal and did not showed foetal anaemia. The pregnancy was carried out till term and patient delivered at 37 weeks of pregnancy with no evidence of foetal anaemia. This case underlines the need of general screening on rare antibodies in all pregnant women and that non-invasive monitoring of foetal anaemia can be done with anti-k titers and middle cerebral artery Doppler.

Foetal distribution and metabolism of N-Nitrosodiethylamine in mice

International Nuclear Information System (INIS)

Brittebo, E.B.; Lindgren, A.; Tjaelve, A.

1981-01-01

In pregnant NMRI mice, low-temperature autoradiography was used to study the distribution of N- 14 C-nitrosodiethylamine in foetal tissues, and autoradiography with heated tape-sections was used to trace nonvolatile metabolites. Autoradiography with 14 C-acetate was used to distinquish the part of the radiography which upon the degradation of N- 14 C-nitrosodiethylamine may be incorporated in the normal metabolism of the tissues. The results indicated that the non-metabolized N-nitrosodiethylamine passed to the foetuses with an even distribution in most foetal tissues on all the studied days of gestation (day 12, 14, 16 and 18). The autoradiographic results further indicated a metabolism of the substance in the mucosa of the foetal bronchial tree and in the foetal liver on day 18 of gestation, but not in earlier stages of pregnancy. This was substantiated by studies in vitro, which showed a marked capacity of the 18 day old foetal lung and liver (in contrast to tissues from 16 day old foetuses) to form 14 CO 2 from the N- 14 C-nitrosodiethylamine. Since the lung and liver are target tissues for the transplacental carcinogenesis of N-nitrosodiethylamine in NMRI mice, a causal relationship between metabolic ability and carcinogenesis may exist in these tissues. (Author)

Radiation dose estimates for radiopharmaceuticals

International Nuclear Information System (INIS)

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

1996-04-01

Tables of radiation dose estimates based on the Cristy-Eckerman adult male phantom are provided for a number of radiopharmaceuticals commonly used in nuclear medicine. Radiation dose estimates are listed for all major source organs, and several other organs of interest. The dose estimates were calculated using the MIRD Technique as implemented in the MIRDOSE3 computer code, developed by the Oak Ridge Institute for Science and Education, Radiation Internal Dose Information Center. In this code, residence times for source organs are used with decay data from the MIRD Radionuclide Data and Decay Schemes to produce estimates of radiation dose to organs of standardized phantoms representing individuals of different ages. The adult male phantom of the Cristy-Eckerman phantom series is different from the MIRD 5, or Reference Man phantom in several aspects, the most important of which is the difference in the masses and absorbed fractions for the active (red) marrow. The absorbed fractions for flow energy photons striking the marrow are also different. Other minor differences exist, but are not likely to significantly affect dose estimates calculated with the two phantoms. Assumptions which support each of the dose estimates appears at the bottom of the table of estimates for a given radiopharmaceutical. In most cases, the model kinetics or organ residence times are explicitly given. The results presented here can easily be extended to include other radiopharmaceuticals or phantoms

The role of ghrelin, leptin and insulin in foetal development

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Magdalena Warchoł

2014-06-01

Full Text Available introduction and objective. The growing epidemic of childhood obesity has forced scientists to search for methods to prevent feeding disorders. Increasing interest in appetite regulating hormones has revealed their influence on energy homeostasis after birth or even in[i] utero[/i]. state of knowledge. The presence of ghrelin in the stomach of human foetuses and the distinctive production in the pancreas of neonates suggests the role of ghrelin in pre- and post-natal development. The neonatal period appears to be a critical time for the formation of adipose tissue-hypothalamus circuits, thus the amount of adipocytes in foetal life may be a major regulator of food intake. Insulin’s orexigenic effect in the arcuate nucleus of the hypothalamus can be a major modulator of foetal development. objective. This review, based on available literature, aims to analyses the role of appetite regulating hormones in foetal development. summary. Different concentrations of hormones, such as ghrelin, leptin and insulin during foetal life raises the question whether or not they can be modulated, thereby avoiding obesity before birth. Children with pancreas agenesis showed smaller body size at birth, which emphasises the probable role of insulin in foetal growth. Study of sheep foetuses with IUGR confirmed these finding. Appetite-regulating hormones show different roles in foetal development and seem to be essential in the perinatal period.

Combining and benchmarking methods of foetal ECG extraction without maternal or scalp electrode data

International Nuclear Information System (INIS)

Behar, Joachim; Oster, Julien; Clifford, Gari D

2014-01-01

Despite significant advances in adult clinical electrocardiography (ECG) signal processing techniques and the power of digital processors, the analysis of non-invasive foetal ECG (NI-FECG) is still in its infancy. The Physionet/Computing in Cardiology Challenge 2013 addresses some of these limitations by making a set of FECG data publicly available to the scientific community for evaluation of signal processing techniques. The abdominal ECG signals were first preprocessed with a band-pass filter in order to remove higher frequencies and baseline wander. A notch filter to remove power interferences at 50 Hz or 60 Hz was applied if required. The signals were then normalized before applying various source separation techniques to cancel the maternal ECG. These techniques included: template subtraction, principal/independent component analysis, extended Kalman filter and a combination of a subset of these methods (FUSE method). Foetal QRS detection was performed on all residuals using a Pan and Tompkins QRS detector and the residual channel with the smoothest foetal heart rate time series was selected. The FUSE algorithm performed better than all the individual methods on the training data set. On the validation and test sets, the best Challenge scores obtained were E1 = 179.44, E2 = 20.79, E3 = 153.07, E4 = 29.62 and E5 = 4.67 for events 1–5 respectively using the FUSE method. These were the best Challenge scores for E1 and E2 and third and second best Challenge scores for E3, E4 and E5 out of the 53 international teams that entered the Challenge. The results demonstrated that existing standard approaches for foetal heart rate estimation can be improved by fusing estimators together. We provide open source code to enable benchmarking for each of the standard approaches described. (paper)

Weldon Spring historical dose estimate

International Nuclear Information System (INIS)

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

1986-07-01

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

Weldon Spring historical dose estimate

Energy Technology Data Exchange (ETDEWEB)

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

1986-07-01

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

High resolution post-mortem MRI of non-fixed in situ foetal brain in the second trimester of gestation. Normal foetal brain development

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Scola, Elisa; Palumbo, Giovanni; Avignone, Sabrina; Cinnante, Claudia Maria [Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico, Neuroradiology Unit, Milan (Italy); Conte, Giorgio [Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico, Neuroradiology Unit, Milan (Italy); Universita degli Studi di Milano, Postgraduation School in Radiodiagnostics, Milan (Italy); Boito, Simona; Persico, Nicola [Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico, Department of Obstetrics and Gynaecology ' L. Mangiagalli' , Milan (Italy); Rizzuti, Tommaso [Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico, Pathology Unit, Milan (Italy); Triulzi, Fabio [Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico, Neuroradiology Unit, Milan (Italy); Universita degli Studi di Milano, Department of Pathophysiology and Transplantation, Milan (Italy)

2018-01-15

To describe normal foetal brain development with high resolution post-mortem MRI (PMMRI) of non-fixed foetal brains. We retrospectively collected PMMRIs of foetuses without intracranial abnormalities and chromosomal aberrations studied after a termination of pregnancy due to extracranial abnormalities or after a spontaneous intrauterine death. PMMRIs were performed on a 3-T scanner without any fixation and without removing the brain from the skull. All PMMRIs were evaluated in consensus by two neuroradiologists. Our analysis included ten PMMRIs (median gestational age (GA): 21 weeks; range: 17-28 weeks). At 19 and 20 weeks of GA, the corticospinal tracts are recognisable in the medulla oblongata, becoming less visible from 21 weeks. Prior to 20 weeks the posterior limb of the internal capsule (PLIC) is more hypointense than surrounding deep grey nuclei; starting from 21 weeks the PLIC becomes isointense, and is hyperintense at 28 weeks. From 19-22 weeks, the cerebral hemispheres show transient layers: marginal zone, cortical plate, subplate, and intermediate, subventricular and germinal zones. PMMRI of non-fixed in situ foetal brains preserves the natural tissue contrast and skull integrity. We assessed foetal brain development in a small cohort of foetuses, focusing on 19-22 weeks of gestation. (orig.)

High resolution post-mortem MRI of non-fixed in situ foetal brain in the second trimester of gestation. Normal foetal brain development

International Nuclear Information System (INIS)

Scola, Elisa; Palumbo, Giovanni; Avignone, Sabrina; Cinnante, Claudia Maria; Conte, Giorgio; Boito, Simona; Persico, Nicola; Rizzuti, Tommaso; Triulzi, Fabio

2018-01-01

To describe normal foetal brain development with high resolution post-mortem MRI (PMMRI) of non-fixed foetal brains. We retrospectively collected PMMRIs of foetuses without intracranial abnormalities and chromosomal aberrations studied after a termination of pregnancy due to extracranial abnormalities or after a spontaneous intrauterine death. PMMRIs were performed on a 3-T scanner without any fixation and without removing the brain from the skull. All PMMRIs were evaluated in consensus by two neuroradiologists. Our analysis included ten PMMRIs (median gestational age (GA): 21 weeks; range: 17-28 weeks). At 19 and 20 weeks of GA, the corticospinal tracts are recognisable in the medulla oblongata, becoming less visible from 21 weeks. Prior to 20 weeks the posterior limb of the internal capsule (PLIC) is more hypointense than surrounding deep grey nuclei; starting from 21 weeks the PLIC becomes isointense, and is hyperintense at 28 weeks. From 19-22 weeks, the cerebral hemispheres show transient layers: marginal zone, cortical plate, subplate, and intermediate, subventricular and germinal zones. PMMRI of non-fixed in situ foetal brains preserves the natural tissue contrast and skull integrity. We assessed foetal brain development in a small cohort of foetuses, focusing on 19-22 weeks of gestation. (orig.)

Apple-peel atresia presenting as foetal intestinal obstruction

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Ashok Yadavrao Kshirsagar

2011-01-01

Full Text Available Apple-peel atresia or Type 3 jejuno-ileal atresia (JIA is an uncommon cause of foetal intestinal obstruction. Bowel obstruction in the foetus is diagnosed on the prenatal ultrasonography only in 50% cases. We report a case in which foetal intestinal obstruction was diagnosed on prenatal ultrasonography. The child showed signs of intestinal obstruction on day one after birth, for which an exploratory laparotomy was performed. Type 3 JIA was found for which resection of atretic segments with jejuno-ascending colon anastomosis was preformed.

An ECG simulator for generating maternal-foetal activity mixtures on abdominal ECG recordings

International Nuclear Information System (INIS)

Behar, Joachim; Andreotti, Fernando; Li, Qiao; Oster, Julien; Clifford, Gari D; Zaunseder, Sebastian

2014-01-01

Accurate foetal electrocardiogram (FECG) morphology extraction from non-invasive sensors remains an open problem. This is partly due to the paucity of available public databases. Even when gold standard information (i.e derived from the scalp electrode) is present, the collection of FECG can be problematic, particularly during stressful or clinically important events. In order to address this problem we have introduced an FECG simulator based on earlier work on foetal and adult ECG modelling. The open source foetal ECG synthetic simulator, fecgsyn, is able to generate maternal-foetal ECG mixtures with realistic amplitudes, morphology, beat-to-beat variability, heart rate changes and noise. Positional (rotation and translation-related) movements in the foetal and maternal heart due to respiration, foetal activity and uterine contractions were also added to the simulator. The simulator was used to generate some of the signals that were part of the 2013 PhysioNet Computing in Cardiology Challenge dataset and has been posted on Physionet.org (together with scripts to generate realistic scenarios) under an open source license. The toolbox enables further research in the field and provides part of a standard for industry and regulatory testing of rare pathological scenarios. (paper)

Foetal stem cell derivation & characterization for osteogenic lineage

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A Mangala Gowri

2013-01-01

Full Text Available Background & objectives: Mesencymal stem cells (MSCs derived from foetal tissues present a multipotent progenitor cell source for application in tissue engineering and regenerative medicine. The present study was carried out to derive foetal mesenchymal stem cells from ovine source and analyze their differentiation to osteogenic linage to serve as an animal model to predict human applications. Methods: Isolation and culture of sheep foetal bone marrow cells were done and uniform clonally derived MSC population was collected. The cells were characterized using cytochemical, immunophenotyping, biochemical and molecular analyses. The cells with defined characteristics were differentiated into osteogenic lineages and analysis for differentiated cell types was done. The cells were analyzed for cell surface marker expression and the gene expression in undifferentiated and differentiated osteoblast was checked by reverse transcriptase PCR (RT PCR analysis and confirmed by sequencing using genetic analyzer. Results: Ovine foetal samples were processed to obtain mononuclear (MNC cells which on culture showed spindle morphology, a characteristic oval body with the flattened ends. MSC population CD45 - /CD14 - was cultured by limiting dilution to arrive at uniform spindle morphology cells and colony forming units. The cells were shown to be positive for surface markers such as CD44, CD54, integrinβ1, and intracellular collagen type I/III and fibronectin. The osteogenically induced MSCs were analyzed for alkaline phosphatase (ALP activity and mineral deposition. The undifferentiated MSCs expressed RAB3B, candidate marker for stemness in MSCs. The osteogenically induced and uninduced MSCs expressed collagen type I and MMP13 gene in osteogenic induced cells. Interpretation & conclusions: The protocol for isolation of ovine foetal bone marrow derived MSCs was simple to perform, and the cultural method of obtaining pure spindle morphology cells was established

Optimisation and evaluation of the foetal dose during a radiotherapy of the right parotid

International Nuclear Information System (INIS)

Marchesi, V.; Noel, A.; Graff, P.; Beckendorf, V.; Peiffert, D.; Noel, A.

2008-01-01

Purpose was to optimize and to estimate the dose delivered to the foetus during a postoperative irradiation of a 5-month twin pregnant woman presenting with adenocarcinoma of the right parotid. The treatment protocol aimed to deliver 66 Gy conformal radiation therapy on the tumour bed associated to a prophylactic irradiation of 50 Gy on the upper cervical nodes. A series of measurements allowed to estimate the delivered dose in the abdomen by the means of an ion chamber inserted in a water phantom placed side by side of an anthropomorphic Alderson Rando phantom simulating the body of the patient from the head to the pelvis. An appropriate optimisation of the number and orientation of beams were performed in order to minimize the peripheral dose, which is mostly dependent of the total number of monitor unit per fraction: cervical nodes and tumour site included in the same fields, limitation of the irradiated volume, 6 MV X-ray beams rather than Cobalt beams. The measured doses at the upper, in the middle and at the lower part of the abdomen were 17.0, 11.0 and 11.9 mGy, respectively, for the entire treatment, representing 0.025, 0.016 and 0.017%, respectively of the prescribed dose. The actions conducted to optimise the treatment allowed to lower doses delivered to the foetus under the limits proposed by international recommendations (100 mGy). Thus, the treatment of the pregnant patient had been performed with a minimized risk for the foetus. (authors)

Communication Profile of Primary School-Aged Children with Foetal Growth Restriction

Science.gov (United States)

Partanen, Lea Aulikki; Olsén, Päivi; Mäkikallio, Kaarin; Korkalainen, Noora; Heikkinen, Hanna; Heikkinen, Minna; Yliherva, Anneli

2017-01-01

Foetal growth restriction is associated with problems in neurocognitive development. In the present study, prospectively collected cohorts of foetal growth restricted (FGR) and appropriate for gestational age grown (AGA) children were examined at early school-age by using the Children's Communication Checklist-2 (CCC-2) to test the hypothesis that…

The MIRD method of estimating absorbed dose

International Nuclear Information System (INIS)

Weber, D.A.

1991-01-01

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

Rapid spread and association of Schmallenberg virus with ruminant abortions and foetal death in Austria in 2012/2013.

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Steinrigl, Adolf; Schiefer, Peter; Schleicher, Corina; Peinhopf, Walter; Wodak, Eveline; Bagó, Zoltán; Schmoll, Friedrich

2014-10-15

Schmallenberg virus (SBV) has emerged in summer-autumn 2011 in north-western Europe. Since then, SBV has been continuously spreading over Europe, including Austria, where antibodies to SBV, as well as SBV genome, were first detected in autumn 2012. This study was performed to demonstrate the dynamics of SBV spread within Austria, after its probable first introduction in summer 2012. True seroprevalence estimates for cattle and small ruminates were calculated to demonstrate temporal and regional differences of infection. Furthermore, the probability of SBV genome detection in foetal tissues of aborted or stillborn cattle and small ruminants as well as in allantoic fluid samples from cows with early foetal losses was retrospectively assessed. SBV first reached Austria most likely in July-August 2012, as indicated by retrospective detection of SBV antibodies and SBV genome in archived samples. From August to October 2012, a rapid increase in seroprevalence to over 98% in cattle and a contemporaneous peak in the detection of SBV genome in foetal tissues and allantoic fluid samples was noted, indicating widespread acute infections. Notably, foetal malformations were absent in RT-qPCR positive foetuses at this time of the epidemic. SBV spread within Austrian cattle reached a plateau phase as early as October 2012, without significant regional differences in SBV seroprevalence (98.4-100%). Estimated true seroprevalences among small ruminates were comparatively lower than in cattle and regionally different (58.3-95.6% in October 2012), potentially indicating an eastward spread of the infection, as well as different infection dynamics between cattle and small ruminants. Additionally, the probability of SBV genome detection over time differed significantly between small ruminant and cattle samples subjected to RT-qPCR testing. Copyright © 2014 Elsevier B.V. All rights reserved.

Foetal loss and enhanced fertility observed in mice treated with Zidovudine or Nevirapine.

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Onwuamah, Chika K; Ezechi, Oliver C; Herbertson, Ebiere C; Audu, Rosemary A; Ujah, Innocent A O; Odeigah, Peter G C

2014-01-01

Health concerns for HIV-infected persons on antiretroviral therapy (ART) have moved from morbidity to the challenges of long-term ART. We investigated the effect of Zidovudine or Nevirapine on reproductive capacity across two mouse generations. A prospective mouse study with drugs administered through one spermatogenic cycle. Mouse groups (16 males and 10 females) were given Zidovudine or Nevirapine for 56 days. Males were mated to untreated virgin females to determine dominant lethal effects. Twenty females (10 treated and 10 untreated) mated with the treated males per dose and gave birth to the F1 generation. Parental mice were withdrawn from drugs for one spermatogenic cycle and mated to the same dams to ascertain if effects are reversible. The F1 generation were exposed for another 56 days and mated to produce the F2 generation. Foetal loss was indicated in the dominant lethal assay as early as four weeks into drug administration to the males. At the first mating of the parental generation to produce the F1 generation, births from 10 dams/dose when the 'father-only' was exposed to Zidovudine (10, 100 and 250 mg/kg) was 3, 2 and 1 while it was 7, 1 and 4 respectively when 'both-parents' were exposed. Similarly births from the parental generation first mating when the 'father-only' was exposed to Nevirapine (5, 50 and 150 mg/kg) was 2, 2 and 0 while it was 6, 5 and 9 respectively when 'both-parents' were exposed. However, fertility was not significantly different neither by dose nor by the parental exposure. The F1 mice mated to produce the F2 generation recorded only one birth. The dominant lethal analysis showed foetal loss occurred when the "fathers-only" were treated while fertility was enhanced when "both-parents" were on therapy at the time of mating.

Foetal loss and enhanced fertility observed in mice treated with Zidovudine or Nevirapine.

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Chika K Onwuamah

Full Text Available Health concerns for HIV-infected persons on antiretroviral therapy (ART have moved from morbidity to the challenges of long-term ART. We investigated the effect of Zidovudine or Nevirapine on reproductive capacity across two mouse generations.A prospective mouse study with drugs administered through one spermatogenic cycle. Mouse groups (16 males and 10 females were given Zidovudine or Nevirapine for 56 days. Males were mated to untreated virgin females to determine dominant lethal effects. Twenty females (10 treated and 10 untreated mated with the treated males per dose and gave birth to the F1 generation. Parental mice were withdrawn from drugs for one spermatogenic cycle and mated to the same dams to ascertain if effects are reversible. The F1 generation were exposed for another 56 days and mated to produce the F2 generation.Foetal loss was indicated in the dominant lethal assay as early as four weeks into drug administration to the males. At the first mating of the parental generation to produce the F1 generation, births from 10 dams/dose when the 'father-only' was exposed to Zidovudine (10, 100 and 250 mg/kg was 3, 2 and 1 while it was 7, 1 and 4 respectively when 'both-parents' were exposed. Similarly births from the parental generation first mating when the 'father-only' was exposed to Nevirapine (5, 50 and 150 mg/kg was 2, 2 and 0 while it was 6, 5 and 9 respectively when 'both-parents' were exposed. However, fertility was not significantly different neither by dose nor by the parental exposure. The F1 mice mated to produce the F2 generation recorded only one birth.The dominant lethal analysis showed foetal loss occurred when the "fathers-only" were treated while fertility was enhanced when "both-parents" were on therapy at the time of mating.

Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

DEFF Research Database (Denmark)

Sorensen, Line C; Maroun, Lisa L; Borch, Klaus

2008-01-01

Aim: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. Methods: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). Conclusion: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired....

Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

DEFF Research Database (Denmark)

Sørensen, Line Carøe; Maroun, Lisa Leth; Borch, K.

2008-01-01

AIM: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. METHODS: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). CONCLUSION: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired Udgivelsesdato: 2008/11...

Metabolism of [14C] testosterone by human foetal and brain tissue

International Nuclear Information System (INIS)

Jenkins, J.S.; Hall, C.J.

1977-01-01

The metabolism of [ 14 C] testosterone in vitro by various areas of the human foetal brain has been studied and compared with that of an adult brain. The predominant metabolites were 5α-dihydrotestosterone and 5α-androstane-3α,17β-diol, and also androstenedione, and all areas of the foetal brain showed similar activity. In the foetal pituitary gland, the activity of 5α-reductase was less prominent than that of 17β-hydroxysteroid-dehydrogenase. Small quantities of oestradiol-17 β were produced from testosterone by the hypothalamus, temporal lobe and amygdala only, and no aromatization could be detected in the pituitary gland. 5α-Reductase activity was much lower in adult brain tissues and no oestradiol was identified in adult temporal lobe tissue. (author)

Estimated radiation dose from timepieces containing tritium

International Nuclear Information System (INIS)

McDowell-Boyer, L.M.

1980-01-01

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

Radiation exposure to foetus and breasts from dental X-ray examinations: effect of lead shields.

Science.gov (United States)

Kelaranta, Anna; Ekholm, Marja; Toroi, Paula; Kortesniemi, Mika

2016-01-01

Dental radiography may involve situations where the patient is known to be pregnant or the pregnancy is noticed after the X-ray procedure. In such cases, the radiation dose to the foetus, though low, needs to be estimated. Uniform and widely used guidance on dental X-ray procedures during pregnancy are presently lacking, the usefulness of lead shields is unclear and practices vary. Upper estimates of radiation doses to the foetus and breasts of the pregnant patient were estimated with an anthropomorphic female phantom in intraoral, panoramic, cephalometric and CBCT dental modalities with and without lead shields. The upper estimates of foetal doses varied from 0.009 to 6.9 μGy, and doses at the breast level varied from 0.602 to 75.4 μGy. With lead shields, the foetal doses varied from 0.005 to 2.1 μGy, and breast doses varied from 0.002 to 10.4 μGy. The foetal dose levels without lead shielding were dental radiographic examination.

Post-mortem MRI of the foetal spine and spinal cord

International Nuclear Information System (INIS)

Widjaja, E.; Whitby, E.H.; Cohen, M.; Paley, M.N.J.; Griffiths, P.D.

2006-01-01

Aims: To compare the findings of post-mortem magnetic resonance imaging (MRI) of the foetal spine with autopsy with a view to using post-mortem MRI as an alternative or adjunct to autopsy, particularly in foetal and neonatal cases. Materials and Methods: The brains and spines of 41 foetuses, with a gestational age range of 14-41 weeks, underwent post-mortem MRI before autopsy. Post-mortem MRI of the brain consisted of T2-weighted sequences in three orthogonal planes and MRI of the spine consisted of T2-weighted sequence in the sagittal and axial planes in all cases and coronal planes in selected cases. Results: Thirty of 41 (78%) foetal spines were found to be normal at autopsy and on post-mortem MRI. Eleven of 41 (22%) foetal spines were abnormal: eight foetuses had myelomeningocoeles and Chiari 2 deformities, one foetus had limited dorsal myeloschisis, one foetus had caudal regression syndrome, and one had diastematomyelia. The post-mortem MRI findings concurred with the autopsy findings in 10/11 of the abnormal cases, the disagreement being the case of diastematomyelia that was shown on post-mortem MRI but was not diagnosed at autopsy. Conclusions: In this series, post-mortem MRI findings agreed with the autopsy findings in 40/41(98%) cases and in one case the post-mortem MRI demonstrated an abnormality not demonstrated at autopsy

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Isolation of human foetal myoblasts and its application for microencapsulation

Science.gov (United States)

Li, Anna Aihua; Bourgeois, Jacqueline; Potter, Murray; Chang, Patricia L

2008-01-01

Abstract Foetal cells secrete more growth factors, generate less immune response, grow and proliferate better than adult cells. These characteristics make them desirable for recombinant modification and use in microencapsulated cellular gene therapeutics. We have established a system in vitro to obtain a pure population of primary human foetal myoblasts under several rounds of selection with non-collagen coated plates and identified by desmin staining. These primary myoblasts presented good proliferation ability and better differentiation characteristics in monolayer and after microencapsulation compared to murine myoblast C2C12 cells based on creatine phosphokinase (CPK), major histocompatibility complex (MHC) and multi-nucleated myotubule determination. The lifespan of primary myoblasts was 70 population doublings before entering into senescent state, with a population time of 18–24 hrs. Hence, we have developed a protocol for isolating human foetal primary myoblasts with excellent differentiation potential and robust growth and longevity. They should be useful for cell-based therapy in human clinical applications with microencapsulation technology. PMID:18366454

STR typing of formalin-fixed paraffin embedded (FFPE) aborted foetal tissue in criminal paternity cases.

Science.gov (United States)

Reshef, Ayeleth; Barash, Mark; Voskoboinik, Lev; Brauner, Paul; Gafny, Roni

2011-03-01

Sexual assault or rape cases occasionally result in unwanted pregnancies. In almost all such cases the foetus is aborted. A forensic laboratory may receive the foetus, the placenta, or paraffin embedded abortion material for paternity testing. Obtaining a foetal profile DNA from a foetus or placenta may not be successful due to the age or condition of the tissue. Moreover, maternal contamination of placental material will invariably result in a mixed DNA profile. However, the use of properly screened abortion material from paraffin blocks will almost always result in obtaining a foetal DNA profile. Furthermore, foetal tissue fixed in paraffin blocks does not require special conditions for submission and storage as required to preserve fresh foetal or placental tissue. As hospitals routinely prepare foetal tissue in paraffin blocks, which should be readily obtainable by forensic laboratories, these samples would appear to be the preferred choice for paternity testing. 2010 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

Early Effects of Lipopolysaccharide-Induced Inflammation on Foetal Brain Development in Rat

Directory of Open Access Journals (Sweden)

Cristina A Ghiani

2011-10-01

Full Text Available Studies in humans and animal models link maternal infection and imbalanced levels of inflammatory mediators in the foetal brain to the aetiology of neuropsychiatric disorders. In a number of animal models, it was shown that exposure to viral or bacterial agents during a period that corresponds to the second trimester in human gestation triggers brain and behavioural abnormalities in the offspring. However, little is known about the early cellular and molecular events elicited by inflammation in the foetal brain shortly after maternal infection has occurred. In this study, maternal infection was mimicked by two consecutive intraperitoneal injections of 200 μg of LPS (lipopolysaccharide/kg to timed-pregnant rats at GD15 (gestational day 15 and GD16. Increased thickness of the CP (cortical plate and hippocampus together with abnormal distribution of immature neuronal markers and decreased expression of markers for neural progenitors were observed in the LPS-exposed foetal forebrains at GD18. Such effects were accompanied by decreased levels of reelin and the radial glial marker GLAST (glial glutamate transporter, and elevated levels of pro-inflammatory cytokines in maternal serum and foetal forebrains. Foetal inflammation elicited by maternal injections of LPS has discrete detrimental effects on brain development. The early biochemical and morphological changes described in this work begin to explain the sequelae of early events that underlie the neurobehavioural deficits reported in humans and animals exposed to prenatal insults.

Parental decision-making after ultrasound diagnosis of a serious foetal abnormality.

Science.gov (United States)

Bijma, Hilmar H; Wildschut, Hajo I J; van der Heide, Agnes; Passchier, Jan; Wladimiroff, Juriy W; van der Maas, Paul J

2005-01-01

The purpose of this article is to provide clinicians who are involved in the field of foetal medicine with a comprehensive overview of theories that are relevant for the parental decision-making process after ultrasound diagnosis of a serious foetal abnormality. Since little data are available of parental decision-making after ultrasound diagnosis of foetal abnormality, we reviewed the literature on parental decision-making in genetic counselling of couples at increased genetic risk together with the literature on general decision-making theories. The findings were linked to the specific situation of parental decision-making after an ultrasound diagnosis of foetal abnormality. Based on genetic counselling studies, several cognitive mechanisms play a role in parental decision-making regarding future pregnancies. Parents often have a binary perception of risk. Probabilistic information is translated into two options: the child will or will not be affected. The graduality of chance seems to be of little importance in this process. Instead, the focus shifts to the possible consequences for future family life. General decision-making theories often focus on rationality and coherence of the decision-making process. However, studies of both the influence of framing and the influence of stress indicate that emotional mechanisms can have an important and beneficial function in the decision-making process. Cognitive mechanisms that are elicited by emotions and that are not necessarily rational can have an important and beneficial function in parental decision-making after ultrasound diagnosis of a foetal abnormality. Consequently, the process of parental decision-making should not solely be assessed on the basis of its rationality, but also on the basis of the parental emotional outcome. Copyright (c) 2005 S. Karger AG, Basel.

Effects of gestational and pregestational diabetes mellitus on the foetal heart: a cross-sectional study.

Science.gov (United States)

Dervisoglu, Pinar; Kosecik, Mustafa; Kumbasar, Serkan

2018-04-01

We examined the foetal cardiac structural and functional characteristics in diabetic pregnancies versus non-diabetic, healthy pregnancies. Between August 2015 and April 2016, 32 pregnant women with pregestational diabetes, 36 pregnant women with gestational diabetes, and 42 healthy pregnant women were scheduled to have foetal echocardiograms to assess cardiac structure and function. In the diabetic groups, the foetal interventricular septum (IVS) thickness was significantly greater than in non-diabetics (p 2 SD from normal. The peak velocity of tricuspid E, and the E/A ratio were significantly lower in the diabetic groups (p diabetic group than in the control group (p  .05). Interventricular septal hypertrophy is the most common structural abnormality in diabetic pregnancies. These changes do not pose a risk to the foetal unless they cause functional impairment. Thus, we believe that it is important for diabetic pregnant women to be monitored for foetal cardiac diastolic dysfunction. Impact statement What is already known on this subject? Pregestational insulin-dependent diabetes mellitus is a relatively common condition in pregnancy, affecting up to 0.5% of the pregnant population. Foetuses of diabetic mothers are at an increased risk of perinatal morbidity and death. Gestational diabetes mellitus is under-recognised and affects up to 4% of pregnancies. Although diabetes mellitus is known to increase the risk of cardiovascular defects and structural changes (myocardial hypertrophy and diastolic dysfunction) due to foetal hyperglycaemia and hyperinsulinism, similar data in women with gestational diabetes is scarce. Moreover, the effect of maternal hyperglycaemia on foetal cardiac structure and function is unclear because of discordant results from previous studies. What do the results of this study add? In this study, we have used foetal echocardiography, two-dimensional US, pulsed wave Doppler and TDI to characterise the foetal cardiac structure and

Adaptation of the ICRP models for the Techa River populations to estimate in utero and postnatal haemopoietic tissue doses from ingested strontium isotopes

International Nuclear Information System (INIS)

Shagina, Natalia; Tolstykh, Evgenia; Degteva, Marina; Fell, Tim; Harrison, John

2008-01-01

Full text: Reliable estimation of tissue doses for exposed individuals is very important in epidemiological studies. Long-term cohort studies of the Techa River populations exposed in the early 1950s due to releases of liquid radioactive wastes from the Mayak plutonium production facility (Southern Urals, Russia) are unique in allowing the quantification of risks from low-level chronic exposure of the general population and providing information on risks for persons exposed in utero. Strontium isotopes were the most important contributors to haemopoietic tissue doses for people living in the riverside settlements. Large-scale monitoring of the exposed population has provided a comprehensive database, including post mortem and in vivo measurements of 90 Sr in bones and whole body, for use in the estimation of doses. The International Commission on Radiological Protection (ICRP) has published biokinetic and dosimetric models for the calculation of doses to members of the public, including doses from in utero exposures and from intakes with breast milk. However, the ICRP models as applied to Sr required modification to provide best estimates of doses to Techa River residents. Adaptations were made to the ICRP model for Sr in children and adults to take account of population-specific features relating to bone mineral turnover and to model age and gender differences in strontium retention. Refinements in the ICRP model for Sr uptake and retention in the fetus were made to improve the treatment of discrimination against Sr, relative to Ca, in transfer from maternal to foetal blood and to take account of population-specific data on the calcium content of the maternal and fetal skeleton. Modification of the ICRP model for Sr transfer in breast-milk included adaptations relating to changes in maternal mineral metabolism during lactation and consideration of population-specific features of breast feeding in the rural population. The improved models were successfully

Regulatory T cells, maternal-foetal immune tolerance and recurrent miscarriage: new therapeutic challenging opportunities.

Science.gov (United States)

Alijotas-Reig, Jaume; Melnychuk, Taisiia; Gris, Josep Maria

2015-03-15

Because maternal alloreactive lymphocytes are not depleted during pregnancy, local and/or systemic mechanisms have to play a key role in altering the maternal immune response. Peripheral T regulatory cells (pTregs) at the maternal-foetal interface are necessary in situ to prevent early abortion, but only those pTregs that have been previously exposed to paternal alloantigens. It has been showed that pregnancy selectively stimulates the accumulation of maternal Foxp3(+)CD4(+)CD25(+) (Foxp3Tregs) cells with foetal specificity. Interestingly, after delivery, foetal-specific pTregs persist at elevated levels, maintain tolerance to pre-existing foetal antigen, and rapidly re-accumulate during subsequent pregnancy. pTreg up-regulation could be hypothesized as a possible future therapeutic strategy in humans. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

Estimation of dose from chromosome aberration rate

International Nuclear Information System (INIS)

Li Deping

1990-01-01

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

Fetus dose estimate of a pregnant worker

International Nuclear Information System (INIS)

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

2006-01-01

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

Estimation of population dose from all sources in Japan

International Nuclear Information System (INIS)

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

1988-01-01

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

Sonographic correlation of foetal neck circumference and area with gestational age among pregnant women in Port Harcourt, Nigeria.

Science.gov (United States)

Abonyi, Obinna Everistus; Eze, Charles Ugwoke; Onwuzu, Sobechukwu W I

2017-11-01

The purpose of this study was to create a reference range nomogram of foetal neck circumference (FNC) and foetal neck area (FNA) in a Nigerian population using polynomial regression models. This cross-sectional study involved 723 pregnant women between 14 and 40 weeks of gestation. Axial measurements of the FNC and FNA were obtained in three measurements and the mean taken as the final value and the 5th, 50th and 95th percentiles for each foetal gestational age (FGA) were calculated. FNC and FNA correlated strongly with FGA, biparietal diameter, abdominal circumference, head circumference, and femoral length. Cubic models fitted the FNC vs FGA, and FNA vs. FGA values, and the mathematical relationships are given as: [Formula: see text] [Formula: see text] [Formula: see text]. Nomograms of FNC and FNA are thus generated. Impact statement The foetal neck circumference (FNC) and foetal neck area (FNA) can serve as predictors of foetal gestational age (FGA) since they correlate strongly and positively with FGA and known biometric parameters. The measurements obtained vary with the population studied. This study provides a nomogram of the FNA and FNC for an African population. The values correlate with that of the Caucasian population up to 32 weeks FGA. Interestingly, FNA and FNC measurements demonstrate high correlation but poor agreement in measurements between sonographers. Even though FNA and FNC could be used as predictors of foetal gestational age, the measurements vary significantly between sonographers. This is attributable to the difficulty in obtaining a satisfactory axial view of foetal neck, which is dependent on foetal presentation.

Carcinoma in situ testis displays permissive chromatin modifications similar to immature foetal germ cells

DEFF Research Database (Denmark)

Almstrup, K; Nielsen, J E; Mlynarska, O

2010-01-01

The majority of testicular germ cell cancers develop through a pre-invasive carcinoma in situ (CIS) stage. The CIS cell is a neoplastic counterpart of foetal germ cells. During their development, foetal germ cells undergo extensive and essential epigenetic modifications, but little is known about...

[Foetal/neonatal alloimmune thrombocytopenia. A review and case report].

Science.gov (United States)

Rodríguez Wilhelmi, P; Aranguren, A; Muñiz, E; Aranburu, E; Ezpeleta, I; Ardanaz, M F; Ayape, M L

2008-01-01

Foetal/neonatal alloimmune thrombocytopenia is the most common cause of severe thrombocytopenia in the newborn. It is an acute disorder which implies that foetal platelets are destroyed during the pregnancy due to a maternal alloimmune IgG antibody. More than 80% of Caucasians are HPA-1a specific. Intracranial haemorrhage, which occurs in 30% of cases, is the most serious complication, with a 10% mortality rate or a 20% rate of irreversible neurological sequels. The high risk of a recurrence of serious bleeding in future pregnancies led us to consider prophylaxis or prenatal treatment. An early diagnosis of this process allows an effective therapy to be carried out based on the infusion of compatible phenotype HPA platelets or endovenous immunoglobulins. We present the case of a 27 year old pregnant woman, who in the 35th week of a second pregnancy was diagnosed using echography with a bilateral foetal hydrocephaly. After caesarean delivery in the 36th week, the newborn presented haematomas in the left shoulder and gluteus, macrocephalia with tension of the fontanellas and hemorrhagic cerebrospinal fluid after insertion of an external ventricular derivation catheter. The haemogram revealed a severe trombocytopenia (9 x 109/L). In the light of clinical suspicion of foetal/neonatal alloimmune thrombocytopenia, infusion was made of platelets from a non-phenotyped donor for the HPA-1a system, and an endovenous immunoglobulin treatment was followed, with a recovery of platelet counts, but with neurological sequels that are probably irreversible. The immunohaematologal study confirmed the negative HPA-1a maternal phenotype, the neonatal HPA-1a positive phenotype and the presence of anti-HPA-1a alloantibodies in the maternal serum. Nowadays, the prophylaxis and treatment continue to be a controversial issue that is open to discussion, as is the possibility of implementing antenatal screening.

THE OCCURRENCE OF FOETAL DWARFIST{ IN THE ANGORA ...

African Journals Online (AJOL)

Foetal dwarfism following heat stress during preg- nancy has been .... with a low heat tolerance coefficient. lt has also been surmised that ... system by abnormal levels of maternal hormones. Star- ... and hence growth suppressing actions.

Occupational dose estimates for a monitored retrievable storage facility

International Nuclear Information System (INIS)

Harty, R.; Stoetzel, G.A.

1986-06-01

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

Paracetamol (acetaminophen), aspirin (acetylsalicylic acid) and indomethacin are anti-androgenic in the rat foetal testis

DEFF Research Database (Denmark)

Kristensen, David Møbjerg; Lesné, L.; Fol, V. Le

2012-01-01

on gestational day 14.5 rat testes, we herein show that testosterone production was inhibited by paracetamol, at doses of 0.1??m to 100??m. Similar results were obtained for aspirin (1?100??m) and indomethacin (10??m). The production of the other Leydig cell hormone, Insl3, was not disrupted by exposure...... inhibit testosterone production in rat foetal testes in vitro and that these compounds had no effect on gonocyte survival. Parallel determinations of prostaglandin D2 (PGD2) production indicated that the effects of paracetamol and aspirin on PGD2 and testosterone were not connected, whereas the effects...

Transmission dose estimation algorithm for in vivo dosimetry

International Nuclear Information System (INIS)

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

2002-01-01

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

Transmission dose estimation algorithm for in vivo dosimetry

Energy Technology Data Exchange (ETDEWEB)

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

2002-07-01

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

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

International Nuclear Information System (INIS)

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

1995-01-01

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

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

International Nuclear Information System (INIS)

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

1993-01-01

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

STUDY OF BIOCHEMICAL PARAMETERS IN AMNIOTIC FLUID FOR ASSESSMENT OF FOETAL MATURITY IN CASES OF NORMAL PREGNANCY

Directory of Open Access Journals (Sweden)

Leela

2015-11-01

Full Text Available Assessment of foetal maturity had been proven of value in evaluating the foetal condition. Accurate assessment of foetal maturity is essential for the proper timing of delivery in various risk pregnancies. Amniotic Fluid analysis for foetal maturity had been of proven value. In the present study, study of biochemical parameters in amniotic fluid in respect of Creatinine, Uric Acid, Urea, Total Proteins, and Electrolytes i.e. Sodium, Potassium and Chloride has been done, along with Serum Electrolytes. Standard methodologies were adopted. The observations in the present study correlated with the works of Chadick et al and Pitkin and Zwirek. The levels of Creatinine, Uric Acid and Urea in Amniotic Fluid showed elevation, while Total Proteins and Serum Sodium showed a decline, as gestation progressed. The Serum and Amniotic Fluid Potassium and Chloride levels remain almost constant throughout the pregnancy. Thus, it is observed that the use of multiple parameters is desirable for accurate assessment of foetal maturity.

Adult head CT scans: the uncertainties of effective dose estimates

International Nuclear Information System (INIS)

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

2008-01-01

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

Antenatal surveillance through estimates of the sources underlying the abdominal phonogram: a preliminary study

International Nuclear Information System (INIS)

Jiménez-González, A; James, C J

2013-01-01

Today, it is generally accepted that current methods for biophysical antenatal surveillance do not facilitate a comprehensive and reliable assessment of foetal well-being and that continuing research into alternative methods is necessary to improve antenatal monitoring procedures. In our research, attention has been paid to the abdominal phonogram, a signal that is recorded by positioning an acoustic sensor on the maternal womb and contains valuable information about foetal status, but which is hidden by maternal and environmental sources. To recover such information, previous work has used single-channel independent component analysis (SCICA) on the abdominal phonogram and successfully retrieved estimates of the foetal phonocardiogram, the maternal phonocardiogram, the maternal respirogram and noise. The availability of these estimates made it possible for the current study to focus on their evaluation as sources for antenatal surveillance purposes. To this end, the foetal heart rate (FHR), the foetal heart sounds morphology, the maternal heart rate (MHR) and the maternal breathing rate (MBR) were collected from the estimates retrieved from a dataset of 25 abdominal phonograms. Next, these parameters were compared with reference values to quantify the significance of the physiological information extracted from the estimates. As a result, it has been seen that the instantaneous FHR, the instantaneous MHR and the MBR collected from the estimates consistently followed the trends given by the reference signals, which is a promising outcome for this preliminary study. Thus, as far as this study has gone, it can be said that the independent traces retrieved by SCICA from the abdominal phonogram are likely to become valuable sources of information for well-being surveillance, both foetal and maternal. (paper)

Fast skin dose estimation system for interventional radiology.

Science.gov (United States)

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

2018-03-01

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

CY 1995 radiation dose reconciliation report and resulting CY 1996 dose estimate for the 324 nuclear facility

International Nuclear Information System (INIS)

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

1996-04-01

In this report, the dose estimate for CY 1995 is reconciled by month wih actual doses received. Results of the reconciliation were used to revise estimates of worker dose for CY 1996. Resulting dose estimate for the facility is also included. Support for two major programs (B-Cell Cleanout and Surveillance and Maintenance) accounts for most of the exposure received by workers in the faility. Most of the expousre received by workers comes from work in the Radiochemical Engineering Complex airlock. In spite of schedule and work scope changes during CY 1995, dose estimates were close to actual exposures received. A number of ALARA measures were taken throughout the year; exposure reduction due to those was 20.6 Man-Rem, a 28% reduction from the CY 1995 estimate. Baseline estimates for various tasks in the facility were used to compile the CY 1996 dose estimate of 45.4 Man-Rem; facility goal for CY 1996 is to reduce worker dose by 20%, to 36.3 Man-Rem

Dose estimation from residual and fallout radioactivity, 1

International Nuclear Information System (INIS)

Takeshita, Kenji

1975-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1982-05-01

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

Ingestion of Nevada Test Site Fallout: Internal dose estimates

International Nuclear Information System (INIS)

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

1996-01-01

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

Epigenetic features of testicular germ cell tumours in relation to epigenetic characteristics of foetal germ cells

DEFF Research Database (Denmark)

Kristensen, Dina Graae; Skakkebæk, Niels E; Rajpert-De Meyts, Ewa

2013-01-01

in humans. However, the common precursor of testicular cancers- the carcinoma in situ (CIS) cell- is thought to be an arrested foetal germ cell. Therefore studies of CIS cells may leverage information on human foetal germ cell development and, in particular, when neoplastic transformation is initiated....... In this review, we will focus on current knowledge of the epigenetics of CIS cells and relate it to the epigenetic changes occurring in early developing germ cells of mice during specification, migration and colonization. We will focus on DNA methylation and some of the best studied histone modifications like H3...... event in the initiation of testicular germ cell cancer. Even though only sparse information is available on epigenetic cues in human foetal germ cells, these indicate that the developmental patterns differ from the findings in mice and emphasize the need for further studies of foetal germ cell...

Maximum likelihood estimation for cytogenetic dose-response curves

International Nuclear Information System (INIS)

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

1986-01-01

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

Bayesian estimation of dose rate effectiveness

International Nuclear Information System (INIS)

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

2000-01-01

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

Associations Between Maternal-Foetal Attachment and Infant Developmental Outcomes: A Systematic Review.

Science.gov (United States)

Branjerdporn, Grace; Meredith, Pamela; Strong, Jenny; Garcia, Jenniffer

2017-03-01

Objectives Infant developmental outcomes may be influenced by a range of prenatal maternal characteristics. While there is some evidence to suggest that maternal-foetal attachment may be associated with infant developmental outcomes, there is a need to systematically review this evidence to guide future research and clinical practice. Methods Five electronic databases were systematically scanned. Key journals and reference lists were hand-searched. Papers were included if: (1) pregnant women were assessed for maternal-foetal attachment; (2) the infants were later assessed, under 2 years old, for any developmental outcome (e.g., social-emotional, cognition, motor, language, adaptive behaviour); and (3) they were published in English. Two independent reviewers used the STROBE checklist to appraise the quality of each paper. Results Of the 968 papers identified, eight were included in the review, and four of these were of low quality (infant temperament (n = 5), adaptive behaviour (e.g., colic, sleep) (n = 2), and milestone attainment (n = 1). There is some evidence to suggest that lower maternal-foetal attachment is related to suboptimal developmental outcomes. However, these results should be interpreted with caution due to the limited and low quality studies available. Conclusions Although maternal-foetal attachment may be associated with infant developmental outcomes, future research is required which: (1) considers a range of developmental outcomes, (2) has increased scientific rigour, (3) assesses mother-infant dyads at different prenatal and postnatal time points, and (4) examines different target populations.

The human placenta--an alternative for studying foetal exposure

DEFF Research Database (Denmark)

Myren, Maja; Mose, Tina; Mathiesen, Line

2007-01-01

Pregnant women are daily exposed to a wide selection of foreign substances. Sources are as different as lifestyle factors (smoking, daily care products, alcohol consumption, etc.), maternal medication or occupational/environmental exposures. The placenta provides the link between mother and foetus......, and though its main task is to act as a barrier and transport nutrients and oxygen to the foetus, many foreign compounds are transported across the placenta to some degree and may therefore influence the unborn child. Foetal exposures to environmental and medicinal products may have impact on the growth...... of the foetus (e.g. cigarette smoke) and development of the foetal organs (e.g. methylmercury and thalidomide). The scope of this review is to give insight to the placental anatomy, development and function. Furthermore, the compounds physical properties and the transfer mechanism across the placental barrier...

Assessment of growth dynamics of human cranium middle fossa in foetal period.

Science.gov (United States)

Skomra, Andrzej; Kędzia, Alicja; Dudek, Krzysztof; Bogacz, Wiesław

2014-01-01

Available literature analysis demonstrated smallness of studies of cranial base. The goal of the study was to analyse the medial fossa of the human cranium in the foetal period against other fossae. Survey material consisted of 110 human foetuses at a morphological age of 16-28 weeks of foetal life, CRL 98-220 mm. Anthropological, preparation method, reverse method and statistical analysis were utilized. The survey incorporated the following computer programmes: Renishaw, TraceSurf, AutoCAD, CATIA. The reverse method seems especially interesting (impression with polysiloxane (silicone elastomer of high adhesive power used in dentistry) with 18 D 4823 activator. Elicited impression accurately reflected complex shape of cranium base. On assessing the relative rate of cranium medial fossa, the rate was found to be stable (linear model) for the whole of the analysed period and is 0.19%/week, which stands for the gradual and steady growth of the middle fossa in relation to the whole of the cranium base. At the same time, from the 16th till 28th week of foetal life, relative volume of the cranium middle fossa increases more intensively than cranium anterior fossa, whereas the cranium middle fossa volume as compared with the cranium posterior fossa is definitely slower. In the analysed period, the growth rate of the cranium base middle fossa was bigger in the 4th and 5th weeks than in the 6th and 7th weeks of foetal life. The investigations revealed cranium base asymmetry of the left side. Furthermore, the anterior fossae volume on the left side is significantly bigger than the one of the fossae on the right side. Volume growth rate is more intensive in the 4th and 5th than in the 6th and 7th weeks of foetal life. In the examined period, the relative growth rate of cranium base middle fossa is 0.19%/week and it is stable - linear model. The study revealed correlations in the form of mathematical models, which enabled foetuses age assessment.

Nonparametric estimation of benchmark doses in environmental risk assessment

Science.gov (United States)

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

2013-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-06-15

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

A Web-Based System for Bayesian Benchmark Dose Estimation.

Science.gov (United States)

Shao, Kan; Shapiro, Andrew J

2018-01-11

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

Dose Estimation from Daily and Weekly Dosimetry Data

International Nuclear Information System (INIS)

Ostrouchov, G.

2001-01-01

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

Dose Estimation from Daily and Weekly Dosimetry Data

Energy Technology Data Exchange (ETDEWEB)

Ostrouchov, G.

2001-11-16

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

Dose reduction - the radiologist's view

International Nuclear Information System (INIS)

Russell, J.G.B.

1984-01-01

The magnitude of the exposure to ionising radiation dominates radiological practice in only three fields, i.e. foetal radiography, mammography and computed tomography. The balance between risk and benefit are briefly examined. The types of hazard considered are carcinogenesis, genetic injury and organogenesis. Ways of achieving a reduction of the dose to the patient are also briefly discussed. (U.K.)

Spirit(ed) away: preventing foetal alcohol syndrome with ...

African Journals Online (AJOL)

Foetal alcohol syndrome (FAS) is a growing concern in South Africa. In the Western Cape, prevalence rates for FAS are the highest in the world. Not surprisingly, the Western Cape also has some of the highest levels of alcohol consumption per capita. Although FAS is primarily caused by alcohol consumption during ...

Estimates of bias and uncertainty in recorded external dose

International Nuclear Information System (INIS)

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

1994-10-01

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

beta- and gamma-Comparative dose estimates on Eniwetok Atoll

Energy Technology Data Exchange (ETDEWEB)

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

1982-05-01

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

Automated dose estimation for lost or damaged dosimeters

International Nuclear Information System (INIS)

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

1988-01-01

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

Do Thyroid Disrupting Chemicals Influence Foetal Development during Pregnancy?

Science.gov (United States)

Hartoft-Nielsen, Marie-Louise; Boas, Malene; Bliddal, Sofie; Rasmussen, Åase Krogh; Main, Katharina; Feldt-Rasmussen, Ulla

2011-01-01

Maternal euthyroidism during pregnancy is crucial for normal development and, in particular, neurodevelopment of the foetus. Up to 3.5 percent of pregnant women suffer from hypothyroidism. Industrial use of various chemicals—endocrine disrupting chemicals (EDCs)—has been shown to cause almost constant exposure of humans with possible harmful influence on health and hormone regulation. EDCs may affect thyroid hormone homeostasis by different mechanisms, and though the effect of each chemical seems scarce, the added effects may cause inappropriate consequences on, for example, foetal neurodevelopment. This paper focuses on thyroid hormone influence on foetal development in relation to the chemicals suspected of thyroid disrupting properties with possible interactions with maternal thyroid homeostasis. Knowledge of the effects is expected to impact the general debate on the use of these chemicals. However, more studies are needed to elucidate the issue, since human studies are scarce. PMID:21918727

Study of foetal heart rate patterns in pregnancy with intra-uterine growth restriction during antepartum period

International Nuclear Information System (INIS)

Fardiazar, Z.; Abassalizade, F.

2013-01-01

Objectives: To evaluate foetal heart rate pattern during antepartum period in pregnancies suffering from intra-uterine growth restriction. Methods: The case control study was conducted at the Alzahra Hospital, Tabriz, Iran from April 2008 to April 2011. It comprised 100 pregnancies with intra-uterine growth restriction and 92 normal pregnancies. The foetal heart rate pattern including basal heart rate, beat-to-beat variation, non-stress test (NST) result and acceleration and deceleration patterns of the heart rate were determined in both groups during the antepartum period. Findings were compared between the two groups and their relation with pregnancy-foetal outcomes was specified in the case group. SPSS 15 was used for statistical analysis. Results: There was no statistically significant difference between the foetus mean basal heart rate in the two groups (p <0.960). Frequency of cases with non-reactive non-stress test in the Cases was significantly higher than Controls (p <0.005). The difference in heart rate acceleration was also not statistically significant (p <0.618). Frequency of cases with low birth weight and caesarian was non-significantly but borderline higher among the Cases (p <0.081 and 0.060, respectively). Conclusion: Abnormal foetal heart rate pattern is more common in pregnancies marked by intra-uterine growth restriction and is directly associated with worse pregnancy/foetal outcomes. (author)

Convolution-based estimation of organ dose in tube current modulated CT

Science.gov (United States)

Tian, Xiaoyu; Segars, W. Paul; Dixon, Robert L.; Samei, Ehsan

2016-05-01

Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460-7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18-70 years, weight range: 60-180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ({{h}\\text{Organ}} ) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} with the organ dose coefficients ({{h}\\text{Organ}} ). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled. The

Estimation of 18FDG doses's cost

International Nuclear Information System (INIS)

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

2013-01-01

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

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

International Nuclear Information System (INIS)

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

1994-01-01

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

Temporary hindlimb paresis following dystocia due to foetal macrosomia in a Celebes crested macaque (Macaca nigra).

Science.gov (United States)

Debenham, John James; Bettembourg, Vanessa; Østevik, Liv; Modig, Michaela; Jâderlund, Karin Hultin; Lervik, Andreas

2017-04-01

A multiparous Celebes crested macaque presented with dystocia due to foetal macrosomia, causing foetal mortality and hindlimb paresis. After emergency caesarean section, recovery of motor function took 1 month before hindlimbs were weight bearing and 2 months before re-integration with the troop. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Developmental origins of adult health and disease: the role of periconceptional and foetal nutrition.

Science.gov (United States)

McMillen, I Caroline; MacLaughlin, Severence M; Muhlhausler, Beverly S; Gentili, Sheridan; Duffield, Jaime L; Morrison, Janna L

2008-02-01

The 'developmental origins of adult health and disease' hypothesis stated that environmental factors, particularly maternal undernutrition, act in early life to programme the risks for adverse health outcomes, such as cardiovascular disease, obesity and the metabolic syndrome in adult life. Early physiological tradeoffs, including activation of the foetal hypothalamo-pituitary-adrenal (HPA) axis, confer an early fitness advantage such as foetal survival, while incurring delayed health costs. We review the evidence that such tradeoffs are anticipated from conception and that the periconceptional nutritional environment can programme the developmental trajectory of the stress axis and the systems that maintain and regulate arterial blood pressure. There is also evidence that restriction of placental growth and function, results in an increased dependence of the maintenance of arterial blood pressure on the sequential recruitment of the sympathetic nervous system and HPA axis. While the 'early origins of adult disease' hypothesis has focussed on the impact of maternal undernutrition, an increase in maternal nutritional intake and in maternal body mass intake has become more prevalent in developed countries. Exposure to overnutrition in foetal life results in a series of central and peripheral neuroendocrine responses that in turn programme development of the fat cell and of the central appetite regulatory system. While the physiological responses to foetal undernutrition result in the physiological trade off between foetal survival and poor health outcomes that emerge after reproductive senescence, exposure to early overnutrition results in poor health outcomes that emerge in childhood and adolescence. Thus, the effects of early overnutrition can directly impact on reproductive fitness and on the health of the next generation. In this context, the physiological responses to relative overnutrition in early life may directly contribute to an intergenerational cycle of

Determination of first pregnancy and foetal measurements in Egyptian Baladi goats (Capra hircus

Directory of Open Access Journals (Sweden)

Hussein A. Amer

2008-06-01

Full Text Available This study was conducted using B-mode transrectal (TR and transabdominal (TA ultrasonography to determine early pregnancy and fetometry. A total of 110 does aged between 8 and 36 months were used. The detection of early pregnancy and foetal number was measured. The relationship between gestation age and crown-rump length (CRL and bi-parietal diameter (BPD was determined from days 40 to 109 of gestation. The accuracy of foetal sexing was determined by differentiation of genital tubercle (GT from days 40 to 109 of gestation and then followed up after birth. The examination revealed 95.5% of does were pregnant, with 100% accuracy in detecting pregnancy for positive cases. The foetal number was 45.7% and 54.3% for single and twins/triplets. The TR probe enabled more reliable and early recognition of foetal fluid (5 days and heart beats (4 days than the TA probe. The TR observation of heart beats is recommended as conclusive evidence of the presence of a live foetus. The TA convex probe was used from days 40-89 to measure CRL and from days 40-109 to measure BPD. The relation between gestational age and CRL or BPD were highly significant (p0.05 higher in single, compared to multiple pregnancies. In total, 83.3% and 70.2% of single and twins and triplets were sexed. After birth, one case was misdiagnosed by ultrasound, i.e. 83.3% (single and 68.4% (twins and triplets were sexed. However, identification of GT in male foetuses was possible from day 40 onwards. From a total 105 scanned does, 80 (76.2% were sexed and 75.2% of cases were sexed after birth. B-mode real-time ultrasonography is recommended as a reliable means that can be used in field conditions to provide early detection of gestation as early as 19-27 days after mating, for CRL or BPD measuring and foetal sexing from day 40 of gestation onwards.

Determination of first pregnancy and foetal measurements in Egyptian Baladi goats (Capra hircus).

Science.gov (United States)

Amer, Hussein A

2008-01-01

This study was conducted using B-mode transrectal (TR) and transabdominal (TA) ultrasonography to determine early pregnancy and fetometry. A total of 110 does aged between 8 and 36 months were used. The detection of early pregnancy and foetal number was measured. The relationship between gestation age and crown-rump length (CRL) and bi-parietal diameter (BPD) was determined from days 40 to 109 of gestation. The accuracy of foetal sexing was determined by differentiation of genital tubercle (GT) from days 40 to 109 of gestation and then followed up after birth. The examination revealed 95.5% of does were pregnant, with 100% accuracy in detecting pregnancy for positive cases. The foetal number was 45.7% and 54.3% for single and twins/triplets. The TR probe enabled more reliable and early recognition of foetal fluid (5 days) and heart beats (4 days) than the TA probe. The TR observation of heart beats is recommended as conclusive evidence of the presence of a live foetus. The TA convex probe was used from days 40-89 to measure CRL and from days 40-109 to measure BPD. The relation between gestational age and CRL or BPD were highly significant (p0.05) higher in single, compared to multiple pregnancies. In total, 83.3% and 70.2% of single and twins and triplets were sexed. After birth, one case was misdiagnosed by ultrasound, i.e. 83.3% (single) and 68.4% (twins and triplets) were sexed. However, identification of GT in male foetuses was possible from day 40 onwards. From a total 105 scanned does, 80 (76.2%) were sexed and 75.2% of cases were sexed after birth. B-mode real-time ultrasonography is recommended as a reliable means that can be used in field conditions to provide early detection of gestation as early as 19-27 days after mating, for CRL or BPD measuring and foetal sexing from day 40 of gestation onwards.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-12-15

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

Dose estimates in Japan following the Chernobyl reactor accident

International Nuclear Information System (INIS)

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

1988-02-01

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

umbilical cord parameters in ilorin: correlates and foetal outcome

African Journals Online (AJOL)

2014-08-08

Aug 8, 2014 ... The foetal outcomes were assessed by APGAR scores, birth weight, admission to neonatal intensive ... between the umbilical cord parameters and perinatal events such as Apgar scores and birth weight. .... Suzuki S, Fuse Y. Length of the Umbilical Cord and. Perinatal Outcomes in Japanese Singleton ...

Monte Carlo estimation of the absorbed dose in computed tomography

Energy Technology Data Exchange (ETDEWEB)

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

2016-05-15

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

Correlation among foetal number, corpora lutea and plasma progesterone in rockland-swiss mice. [Progesterone determination by radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Simon, N G; Bridges, R S; Gandelmann, R [Rutgers - the State Univ., New Brunswick. NJ (USA). Dept. of Psychology; Rutgers - the State Univ., Newark, NJ (USA). Inst. of Animal Behavior)

1978-01-01

The relationship among plasma progesterone, number of corpora lutea, and foetal number was assessed in Rockland-Swiss albino mice. While number of corpora lutea and foetal number were significantly correlated, neither was related to plasma progesterone level. This finding in the mouse is similar to results reported in the rabbit.

Age- and gender-specific estimates of cumulative CT dose over 5 years using real radiation dose tracking data in children

International Nuclear Information System (INIS)

Lee, Eunsol; Goo, Hyun Woo; Lee, Jae-Yeong

2015-01-01

It is necessary to develop a mechanism to estimate and analyze cumulative radiation risks from multiple CT exams in various clinical scenarios in children. To identify major contributors to high cumulative CT dose estimates using actual dose-length product values collected for 5 years in children. Between August 2006 and July 2011 we reviewed 26,937 CT exams in 13,803 children. Among them, we included 931 children (median age 3.5 years, age range 0 days-15 years; M:F = 533:398) who had 5,339 CT exams. Each child underwent at least three CT scans and had accessible radiation dose reports. Dose-length product values were automatically extracted from DICOM files and we used recently updated conversion factors for age, gender, anatomical region and tube voltage to estimate CT radiation dose. We tracked the calculated CT dose estimates to obtain a 5-year cumulative value for each child. The study population was divided into three groups according to the cumulative CT dose estimates: high, ≥30 mSv; moderate, 10-30 mSv; and low, <10 mSv. We reviewed clinical data and CT protocols to identify major contributors to high and moderate cumulative CT dose estimates. Median cumulative CT dose estimate was 5.4 mSv (range 0.5-71.1 mSv), and median number of CT scans was 4 (range 3-36). High cumulative CT dose estimates were most common in children with malignant tumors (57.9%, 11/19). High frequency of CT scans was attributed to high cumulative CT dose estimates in children with ventriculoperitoneal shunt (35 in 1 child) and malignant tumors (range 18-49). Moreover, high-dose CT protocols, such as multiphase abdomen CT (median 4.7 mSv) contributed to high cumulative CT dose estimates even in children with a low number of CT scans. Disease group, number of CT scans, and high-dose CT protocols are major contributors to higher cumulative CT dose estimates in children. (orig.)

Foetal, neonatal and child vitamin D status and enamel hypomineralization

NARCIS (Netherlands)

J.T. van der Tas (Justin); M.E.C. Elfrink (Marlies); M.P. Heijboer (Rien); Rivadeneira, F. (Fernando); V.W.V. Jaddoe (Vincent); H.W. Tiemeier (Henning); J.D. Schoufour (Josje); H.A. Moll (Henriëtte); E.M. Ongkosuwito (Edwin); E.B. Wolvius (Eppo); R.G. Voortman (Trudy)

2018-01-01

textabstractObjectives: Recent literature suggested that higher vitamin D concentrations in childhood are associated with a lower prevalence of molar incisor hypomineralization (MIH). As tooth development already starts in utero, we aimed to study whether vitamin D status during foetal, postnatal

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-07-15

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

Maternal and foetal outcome in hellp syndrome at tertiary care hospital

International Nuclear Information System (INIS)

Sadaf, N.; Haq, G.; Din, S.S.U.

2013-01-01

Objective: To determine maternal and foetal outcome in patients of Haemolysis, Elevated Liver enzyme and Low Platelet Cont syndrome. Methods: The descriptive case series was conducted at the Gynae Unit II of Civil Hospital, Karachi, over a period of 12 months in two episodes; first from December 28, 2006, to February 28, 2007, and then from September 1, 2007, to June 30, 2008. It comprised 40 consecutive women with pre-ecampsia and eclampsia along with altered platelet count who met the syndrome criteria. A pre-designed proforma was administered for data collection. Maternal and foetal outcomes were noted. SPSS 10 was used for statistical analysis. Result: Among the 40 mothers, cesarean section was the most common outcome (n=24; 60%). Pulmonary oedema was found in 2 (5%) cases, acute renal failure in 10 (25%), disseminated intravascular coagulation in 6 (15%), and abruptio placenta in 5 (12.5%). Intrauterine growth restriction as a foetal outcome was observed in 18 (45%) cases. Pre-term birth was the result in 20 (50%) cases, and perinatal mortality was high (n=23; 57.5%). Conclusion: Management and delivery of HELLP syndrome patients should be performed at tertiary care centres, where highly trained obstetrician, neonatal intensive care unit personnel and Multi-disciplinary facilities are available. Correct diagnosis and timely intervention can decrease the risk of maternal and perinatal mortality. (author)

New risk estimates at low doses

International Nuclear Information System (INIS)

Fry, R.J.M.

1992-01-01

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

Mutation frequencies in male mice and the estimation of genetic hazards of radiation in men: (specific-locus mutations/dose-rate effect/doubling dose/risk estimation)

International Nuclear Information System (INIS)

Russell, W.L.; Kelly, E.M.

1982-01-01

Estimation of the genetic hazards of ionizing radiation in men is based largely on the frequency of transmitted specific-locus mutations induced in mouse spermatogonial stem cells at low radiation dose rates. The publication of new data on this subject has permitted a fresh review of all the information available. The data continue to show no discrepancy from the interpretation that, although mutation frequency decreases markedly as dose rate is decreased from 90 to 0.8 R/min (1 R = 2.6 X 10 -4 coulombs/kg) there seems to be no further change below 0.8 R/min over the range from that dose rate to 0.0007 R/min. Simple mathematical models are used to compute: (a) a maximum likelihood estimate of the induced mutation frequency at the low dose rates, and (b) a maximum likelihood estimate of the ratio of this to the mutation frequency at high dose rates in the range of 72 to 90 R/min. In the application of these results to the estimation of genetic hazards of radiation in man, the former value can be used to calculate a doubling dose - i.e., the dose of radiation that induces a mutation frequency equal to the spontaneous frequency. The doubling dose based on the low-dose-rate data compiled here is 110 R. The ratio of the mutation frequency at low dose rate to that at high dose rate is useful when it becomes necessary to extrapolate from experimental determinations, or from human data, at high dose rates to the expected risk at low dose rates. The ratio derived from the present analysis is 0.33

Dose estimation in embryo or fetus in external fields

International Nuclear Information System (INIS)

Gregori, Beatriz N.

2001-01-01

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

Preliminary evaluation of foetal liver volume by three-dimensional ultrasound in women with gestational diabetes mellitus.

Science.gov (United States)

İlhan, Gülşah; Gültekin, Hüseyin; Kubat, Ayça; Gokmen Karasu, Ayse Filiz; Güngör, Emre Sinan; Zebitay, Galip Ali; Verit Atmaca, Fatma Ferda

2018-03-19

The aim of the study was to assess the standard foetal biometric measurements and foetal liver volume (FLV) in pregnancies complicated by gestational diabetes mellitus (GDM) at the time of GDM screening and to compare the results with foetuses in normal pregnancies. Ninety-seven pregnant women with normal singleton uncomplicated pregnancies between 24 and 28 weeks of gestation were allocated into GDM (+) (n: 33) and GDM (-) (n: 64) groups based on their 75 g oral glucose tolerance test results. Foetal biometric measurements and FLV measurements of the groups were compared. Although there were no significant differences in the standard biometric measurements between the two groups, FLV was significantly higher in the women with GDM (p liver length and foetal liver volume (FLV) have been evaluated as ultrasound parameters of glycaemic control. While the evaluation of foetal liver dimensions has a role in identifying foetal growth acceleration, previous studies addressed patients with insulin-dependent diabetes mellitus rather than gestational diabetes mellitus, utilised two-dimensional ultrasound and did not argue the diagnostic value of these findings. What do the results of this study add? In our study, besides the standard biometric measurements, the FLV measurements were evaluated by a three-dimensional ultrasound. Although there were no significant differences in the standard biometric measurements between the GDM (+) and GDM (-) groups, the FLV was significantly higher in women with GDM. The FLV was found to be a potential predictive factor for GDM. The ROC analysis implied that as a cut-off value of FLV of 32.72 cm 3 for GDM prediction, the sensitivity was 78.8% and the specificity was 56.3%. What are the implications of these findings for clinical practise and/or further research? Screening for GDM with oral glucose tolerance test within the limited weeks of gestation may not always be feasible. On the other hand, the mid-trimester ultrasound scanning

A novel approach for estimating ingested dose associated with paracetamol overdose.

Science.gov (United States)

Zurlinden, Todd J; Heard, Kennon; Reisfeld, Brad

2016-04-01

In cases of paracetamol (acetaminophen, APAP) overdose, an accurate estimate of tissue-specific paracetamol pharmacokinetics (PK) and ingested dose can offer health care providers important information for the individualized treatment and follow-up of affected patients. Here a novel methodology is presented to make such estimates using a standard serum paracetamol measurement and a computational framework. The core component of the computational framework was a physiologically-based pharmacokinetic (PBPK) model developed and evaluated using an extensive set of human PK data. Bayesian inference was used for parameter and dose estimation, allowing the incorporation of inter-study variability, and facilitating the calculation of uncertainty in model outputs. Simulations of paracetamol time course concentrations in the blood were in close agreement with experimental data under a wide range of dosing conditions. Also, predictions of administered dose showed good agreement with a large collection of clinical and emergency setting PK data over a broad dose range. In addition to dose estimation, the platform was applied for the determination of optimal blood sampling times for dose reconstruction and quantitation of the potential role of paracetamol conjugate measurement on dose estimation. Current therapies for paracetamol overdose rely on a generic methodology involving the use of a clinical nomogram. By using the computational framework developed in this study, serum sample data, and the individual patient's anthropometric and physiological information, personalized serum and liver pharmacokinetic profiles and dose estimate could be generated to help inform an individualized overdose treatment and follow-up plan. © 2015 The British Pharmacological Society.

Orthodontics and foetal pathology: a personal view on craniofacial patterning

DEFF Research Database (Denmark)

Kjær, Inger

2009-01-01

This article summarizes the essentials of studies on the craniofacial skeleton performed over 17 years. It presents data from research into foetal pathology resulting in new views on craniofacial patterning and/or fields for further discussion. The fields described cover all areas seen on profile...

Sex Differences in the Association between Foetal Growth and Child Attention at Age Four: Specific Vulnerability of Girls

Science.gov (United States)

Murray, Elizabeth; Matijasevich, Alicia; Santos, Iná S.; Barros, Aluísio J. D.; Anselmi, Luciana; Barros, Fernando C.; Stein, Alan

2015-01-01

Background: Recent evidence suggests that impaired foetal growth may provide an early indication of increased risk of child attention problems. However, despite both foetal growth and child attention problems differing by sex, few studies have examined sex differences in this association. Furthermore, no studies have been conducted in low- and…

Aetiology, maternal and foetal outcome in 60 cases of obstetrical acute renal failure

International Nuclear Information System (INIS)

Khalil, M.A.M.; Azhar, A.; Anwar, N.

2009-01-01

Acute renal failure is a serious complication in pregnancy. Not only does it result in significant maternal morbidity and mortality but also results in significant number of foetal loss. Although incidence of obstetrical acute renal failure has decreased in developed countries but still it is one of the major health problem of developing nations. The objective of this study was to study aetiology, maternal and foetal outcome in obstetrical acute renal failure. This study was conducted at Department of Nephrology, Khyber Teaching Hospital, Peshawar from August 2006 to December 2007. It was a descriptive, case series study. Female patients with pregnancy and acute renal failure, irrespective of age, were included in the study. Patients were thoroughly examined and baseline urea, creatinine, serum electrolytes, peripheral smear, prothrombin time, partial thromboplastin time, fibrinogen degradation products, renal and obstetrical ultrasound were performed on each patient and 24-hr urinary protein and bacterial culture sensitivity on blood, urine or vaginal swabs were done in selected patients. Foetal and maternal outcome were recorded. Data were analysed using SPSS. A total of 60 patients were included in the study. Mean age of the patients was 29 +- 5.4 years and duration of gestation was 33 +- 4.9 weeks. Mean gravidity was 4 +- 2.2. Sixteen patients (26.66%) were treated conservatively while 44 (73.33%) required dialysis. Postpartum haemorrhage was present in 14 (23.33%), postpartum haemorrhage and disseminated intravascular coagulation (DIC) in 11 (18.33%), eclampsia-preeclampsia in 8 (13.33%), antepartum haemorrhage in 8 (13.33%), antepartum haemorrhage with DIC in 6 (10%), DIC alone in 4 (6.66%), obstructed labour in 3 (5%), septic abortion in 3 (3.33%), HELLP (haemolysis elevated liver enzyme and low platelet) in 2 (3.33%), urinary tract infection with sepsis in 1 (1.66%) and puerperal sepsis in 1 (1.66%). Foetal loss was 40 (66.66%). Maternal mortality was 9 (15

Maximum likelihood estimation for cytogenetic dose-response curves

International Nuclear Information System (INIS)

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

1983-10-01

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

Maximum likelihood estimation for cytogenetic dose-response curves

Energy Technology Data Exchange (ETDEWEB)

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

1983-10-01

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

Dose-response relationships and risk estimates for the induction of cancer due to low doses of low-LET radiation

International Nuclear Information System (INIS)

Elaguppillai, V.

1981-01-01

Risk estimates for radiation-induced cancer at low doses can be obtained only by extrapolation from the known effects at high doses and high dose rates, using a suitable dose-response model. The applicability of three different models, linear, sublinear and supralinear, are discussed in this paper. Several experimental studies tend to favour a sublinear dose-response model (linear-quadratic model) for low-LET radiation. However, human epidemiological studies do not exclude any of the dose-response relationships. The risk estimates based on linear and linear quadratic dose-response models are compared and it is concluded that, for low-LET radiation, the linear dose-response model would probably over-estimate the actual risk of cancer by a factor of two or more. (author)

Association of foetal haemoglobin with pancreatic enzymes in sickle ...

African Journals Online (AJOL)

Background/Aim: There are conflicting reports on the potential protective effects of foetal haemoglobin (HbF) in the elimination of symptoms of Sickle cell disease in the patients and reports which correlate the levels of HbF with pancreatic enzymes in SCD are scarce in the literature.This study correlates the levels of HbF on ...

Prenatal malnutrition and subsequent foetal loss risk: Evidence from the 1959-1961 Chinese famine

Directory of Open Access Journals (Sweden)

Shige Song

2013-10-01

Full Text Available Background: Scientists disagree on whether prenatal malnutrition has long-term influences on women's reproductive function, and empirical evidence of such long-term effects remains limited and inconsistent. Methods: Using the retrospective pregnancy history of 12,567 Chinese women collected in a nationally representative sample survey in 2001, this study conducted difference-in-differences analyses to investigate the relationship between prenatal exposure to the 1959-1961 Great Leap Forward Famine in China and the subsequent risk of involuntary foetal loss, including miscarriage and stillbirth, and how this relationship changes between the rural and urban populations. Results: Prenatal exposure to the Great Leap Forward Famine had no long-term effect on women's risk of miscarriage. Such an exposure increased the risk of stillbirth among urban women but not among rural women. Conclusions: The results support the foetal origins hypothesis. The significant urban-rural difference in the effect of prenatal famine exposure on stillbirth suggests the presence of a long-term negative foetal origins effect and a strong selection effect caused by famine-induced population attrition.

Ontogeny of Sex-Related Differences in Foetal Developmental Features, Lipid Availability and Fatty Acid Composition

Directory of Open Access Journals (Sweden)

Consolacion Garcia-Contreras

2017-05-01

Full Text Available Sex-related differences in lipid availability and fatty acid composition during swine foetal development were investigated. Plasma cholesterol and triglyceride concentrations in the mother were strongly related to the adequacy or inadequacy of foetal development and concomitant activation of protective growth in some organs (brain, heart, liver and spleen. Cholesterol and triglyceride availability was similar in male and female offspring, but female foetuses showed evidence of higher placental transfer of essential fatty acids and synthesis of non-essential fatty acids in muscle and liver. These sex-related differences affected primarily the neutral lipid fraction (triglycerides, which may lead to sex-related postnatal differences in energy partitioning. These results illustrate the strong influence of the maternal lipid profile on foetal development and homeorhesis, and they confirm and extend previous reports that female offspring show better adaptive responses to maternal malnutrition than male offspring. These findings may help guide dietary interventions to ensure adequate fatty acid availability for postnatal development.

A comparison of foetal SAR in three sets of pregnant female models

International Nuclear Information System (INIS)

Dimbylow, Peter J; Nagaoka, Tomoaki; Xu, X George

2009-01-01

This paper compares the foetal SAR in the HPA hybrid mathematical phantoms with the 26-week foetal model developed at the National Institute of Information and Communications Technology, Tokyo, and the set of 13-, 26- and 38-week boundary representation models produced at Rensselaer Polytechnic Institute. FDTD calculations are performed at a resolution of 2 mm for a plane wave with a vertically aligned electric field incident upon the body from the front, back and two sides from 20 MHz to 3 GHz under isolated conditions. The external electric field values required to produce the ICNIRP public exposure localized restriction of 2 W kg -1 when averaged over 10 g of the foetus are compared with the ICNIRP reference levels.

Transmission of electric and magnetic foetal cardiac signals in a case of ectopia cordis: the dominant role of the vernix caseosa

International Nuclear Information System (INIS)

Wakai, R.T.; Lengle, J.M.; Leuthold, A.C.

2000-01-01

Foetal electrocardiograms (fECGs) and foetal magnetocardiograms (fMCGs) were recorded in the 26th, 29th and 31st weeks of gestation from a foetus with ectopia cordis - a rare condition in which the heart lies outside the chest wall. This provided an opportunity to study foetal cardiograms uninfluenced by the insulating effects of the foetal skin and vernix caseosa. The fECG of the ectopia cordis foetus was striking. Unlike recordings from age-matched normal foetuses, recordings from this subject had very high signal-to-noise ratio and showed no anomalous signal transmission properties. In contrast, fMCGs recorded from the ectopia cordis foetus and normal foetuses were largely similar. Both showed high signal-to-noise ratio and signal transmission properties consistent with volume conduction. The findings corroborate the hypothesis that high foetal skin resistance due primarily to the vernix caseosa is responsible for the low amplitude and anomalous transmission properties of the normal fECG, and demonstrate that the fMCG is relatively insensitive to conductivity inhomogeneities. (author)

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

Science.gov (United States)

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

2013-11-01

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

Methodology for Estimating Ingestion Dose for Emergency Response at SRS

CERN Document Server

Simpkins, A A

2002-01-01

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

The placenta and foetal membranes of the lesser yellow house bat ...

African Journals Online (AJOL)

A discoidal hemodichorial placenta is present in Scotophilus borbonicus. Evidence is presented which suggests that histotrophic nutrition, in addition to hemotrophic nutrition, occurs. The foetal trophospongium phagocytoses cell debris and glandular secretions derived from the maternal endometrium (decidua basalis).

Materno-foetal outcome of labour in obese women in Yaounde ...

African Journals Online (AJOL)

The objectives of the study were to determine the socio-demographic characteristics of pregnant women with obesity and morbid obesity determine the mean birth weight, foetal length and Apgar score of the babies as well as associated maternal complications. This was a descriptive cross sectional prospective study ...

The placenta and foetal membranes of the lesser yellow house bat ...

African Journals Online (AJOL)

1988-06-05

Jun 5, 1988 ... A discoidal hemodichorial placenta is present in $cotophilus borbonicus. Evidence is presented which suggests that histotrophic nutrition, in addition to hemotrophic nutrition, occurs. The foetal trophospongium phagocytoses cell debris and glandular secretions derived from the maternal endometrium ...

Dose estimation of the THOR BNCT treatment room

International Nuclear Information System (INIS)

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

2006-01-01

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

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

African Journals Online (AJOL)

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

Proton and photon absorbed-dose conversion coefficients for embryo and foetus from top-down irradiation geometry

International Nuclear Information System (INIS)

Chen, J.

2007-01-01

Absorbed-dose conversion coefficients are calculated for the embryo of 8 weeks and the foetus of 3, 6 or 9 months when the mother's body is exposed to protons and photons from top-down (TOP) direction. It provides data sets in addition to other standard irradiation geometries published previously. The TOP-irradiation geometry is considered here, because high-energy particles are often peaked from the TOP direction onboard aircraft. The results show that absorbed-doses from high-energy particles could be underestimated significantly if isotropic (ISO) irradiation geometry is assumed. For protons of 100 GeV, absorbed-doses from TOP irradiation are ∼2.3-2.9 times higher than the doses from ISO irradiation for different foetal ages. For 10 GeV photons, foetal doses from TOP irradiation are ∼6.8-12 times higher than the doses from ISO irradiation. The coefficients from TOP-irradiation geometry are given in wide energy ranges, from 100 MeV to 100 GeV for protons and from 50 V to 10 GeV for photons. They can, therefore, be used in various applications whenever exposure from the TOP-irradiation direction is concerned. (authors)

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Twin Delivery: Comparison of Incidence and Foetal Outcome in two ...

African Journals Online (AJOL)

Background: The incidence of twin delivery in Nigeria may have changed, in view of the worldwide increase in the rates of twinning attributed to increasing maternal age and use of fertility therapies. Objective: To determine the current incidence of twin delivery in Benin City and document the foetal outcome in twins.

Serum levels of antioxidant vitamins in foetal haemoglobin (HbF ...

African Journals Online (AJOL)

Background: sickle cell anaemia (SCA) is one of the commonest health problems of Nigerian children. Method: The serum levels of antioxidant vitamins A (retinol), C (ascorbic acid) and E (alpha-tocopherol) were determined in foetal haemogbobin persistent sickle cell anaemic (Hb SS + F), sickle cell anaemic (Hb SS) and ...

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

Energy Technology Data Exchange (ETDEWEB)

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

1976-03-01

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

Dose estimation for space radiation protection

International Nuclear Information System (INIS)

Xu Feng; Xu Zhenhua; Huang Zengxin; Jia Xianghong

2007-01-01

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

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

International Nuclear Information System (INIS)

Brenner, D.J.

2012-01-01

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

Psychiatric disease in late adolescence and young adulthood. Foetal programming by maternal hypothyroidism?

Science.gov (United States)

Andersen, Stine Linding; Olsen, Jørn; Wu, Chun Sen; Laurberg, Peter

2014-07-01

Lack of maternal thyroid hormones during foetal brain development may lead to structural abnormalities in the brain. We hypothesized that maternal hypothyroidism during the pregnancy could programme the foetus to development of psychiatric disease later in life. Danish nationwide register study. Singletons live-born 1980-1990. Cox proportional hazards model was used to estimate adjusted hazard ratio (aHR) with 95% confidence interval for offspring redemption of ≥2 prescriptions of a psychiatric drug from age 15 to 31 years. Among 542 100 adolescents and young adults included, altogether 3979 (0·7%) were born to mothers with hypothyroidism registered before 1996. In crude analyses, the use of a psychiatric drug was more frequent in late adolescence and young adulthood when the mother had hypothyroidism (P hypothyroidism often also had a psychiatric registration (38·5% vs 27·7%, P hypothyroidism was associated with an increased risk of having redeemed prescriptions of anxiolytics [aHR 1·23 (1·03-1·48)] and antipsychotics [aHR 1·22 (1·03-1·44)] in late adolescence and young adulthood. For antidepressants, aHR was 1·07 (0·98-1·17). The association between maternal hypothyroidism and the use of a psychiatric drug in late adolescence and young adulthood was partly confounded by maternal psychiatric history, but foetal programming by maternal hypothyroidism may be part of the mechanisms leading to the use of anxiolytics and antipsychotics. © 2014 John Wiley & Sons Ltd.

Biogenesis of corticosteroids in monolayer cultures of human foetal adrenal cells

International Nuclear Information System (INIS)

Goodyer, C.G.; Torday, J.S.; St George Hall, C.; Smith, B.T.; Giroud, C.J.P.

1976-01-01

Human foetal adrenal cells were grown in monolayer culture and their steroidogenic capacity observed for up to a month. The cells produced a complex array of steroids and some of their ester sulphates from endogenous as well as from [ 14 C] and[ 3 H] precursors. ACTH stimulated corticoidogenesis, particularly cortisol secretion, and markedly enhanced the incorporation of progesterone and pregnenolone into cortisol. Following incubation with the same precursors, large amounts of radioactivity remained water soluble. From the butanol extractable material of this fraction, dehydroepiandrosterone sulphate was characterized as the main metabolite of pregnenolone and corticosterone and 11-deoxycorticosterone sulphates as the main metabolites of progesterone. With time in culture there was a decrease in steroidogenesis as well as a steady decline in responsiveness to ACTH, mainly manifested by cortisol secretion. The medium from homologous foetal pituitary cultures stimulated cortisol production by the human adrenal cell monolayer. (author)

Patient-specific dose estimation for pediatric chest CT

Energy Technology Data Exchange (ETDEWEB)

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

2008-12-15

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

DNA Extraction from Chorionic Villi for Prenatal Diagnosis of Foetal ...

African Journals Online (AJOL)

BACKGROUND: Extraction of DNA from the chorionic villi is the first major step in the molecular determination of foetal haemoglobin genotype. There are few reports on DNA extraction from the chorionic villi. A desired method should be simple to conduct, reliable and cost effective. OBJECTIVE: The aim of the study was to ...

Estimating effective doses to children from CT examinations

International Nuclear Information System (INIS)

Heron, J.C.L.

2000-01-01

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

Estimation of dose and exposure at sentinel node study

International Nuclear Information System (INIS)

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

2005-01-01

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

Estimated effects on radiation doses from alternatives in a spent fuel transportation system

International Nuclear Information System (INIS)

Schneider, K.J.; Ross, W.A.; Smith, R.I.

1988-07-01

This paper contains the results of a study of estimated radiation doses to the public and workers from the transport of spent fuel from commercial nuclear power reactors to a geologic repository. A postulated reference rail/legal-weight truck transportation system is defined that would use current transportation technology, and provide a breakdown of activities and time/distance/dose-rate estimates for each activity within the system. Collective doses are estimated for each of the major activities at the reactor site, in transit, and at the repository receiving facility. Annual individual doses to the maximally exposed individuals or groups of individuals are also estimated. The dose-reduction potentials and costs are estimated for a total of 17 conceptual alternatives and subalternatives to the postulated reference system. Most of the alternatives evaluated are estimated to provide both cost and dose reductions. The major conclusion is that the potential exists for significant future reductions in radiation doses to the public and workers and for reductions in costs compared to those based on a continuation of past practices in the US

Estimated effects on radiation doses from alternatives in a spent fuel transportation system

International Nuclear Information System (INIS)

Schneider, K.J.; Ross, W.A.; Smith, R.I.

1988-01-01

This paper contains the results of a study of estimated radiation doses to the public and workers from the transport of spent fuel from commercial nuclear power reactors to a geologic repository. A postulated reference rail/legal-weight truck transportation system is defined that would use current transportation technology, and provide a breakdown of activities and time/distance/dose-rate estimates for each activity within the system. Collective doses are estimated for each of the major activities at the reactor site, in transit, and at the repository receiving facility. Annual individual doses to the maximally exposed individuals or groups of individuals also estimated. The dose-reduction potentials and costs are estimated for a total of 17 conceptual alternatives and subalternatives to the postulated reference system. Most of the alternatives evaluated are estimated to provide both cost and dose reductions. The major conclusion is that the potential exists for significant future reductions in radiation doses to the public and workers and for reductions in costs compared to those based on a continuation of past practices in the U.S

Simplification of an MCNP model designed for dose rate estimation

Science.gov (United States)

Laptev, Alexander; Perry, Robert

2017-09-01

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

Where does distance matter? Distance to the closest maternity unit and risk of foetal and neonatal mortality in France.

Science.gov (United States)

Pilkington, Hugo; Blondel, Béatrice; Drewniak, Nicolas; Zeitlin, Jennifer

2014-12-01

The number of maternity units has declined in France, raising concerns about the possible impact of increasing travel distances on perinatal health outcomes. We investigated impact of distance to closest maternity unit on perinatal mortality. Data from the French National Vital Statistics Registry were used to construct foetal and neonatal mortality rates over 2001-08 by distance from mother's municipality of residence and the closest municipality with a maternity unit. Data from French neonatal mortality certificates were used to compute neonatal death rates after out-of-hospital birth. Relative risks by distance were estimated, adjusting for individual and municipal-level characteristics. Seven percent of births occurred to women residing at ≥30 km from a maternity unit and 1% at ≥45 km. Foetal and neonatal mortality rates were highest for women living at maternity unit. For foetal mortality, rates increased at ≥45 km compared with 5-45 km. In adjusted models, long distance to a maternity unit had no impact on overall mortality but women living closer to a maternity unit had a higher risk of neonatal mortality. Neonatal deaths associated with out-of-hospital birth were rare but more frequent at longer distances. At the municipal-level, higher percentages of unemployment and foreign-born residents were associated with increased mortality. Overall mortality was not associated with living far from a maternity unit. Mortality was elevated in municipalities with social risk factors and located closest to a maternity unit, reflecting the location of maternity units in deprived areas with risk factors for poor outcome. © The Author 2014. Published by Oxford University Press on behalf of the European Public Health Association.

Biological dose estimation and comet analysis of the victims in a high dose 60Co radiation accident

International Nuclear Information System (INIS)

Chen Ying; Liu Xiulin; Luo Yisheng; Li You; Yao Bo

2007-01-01

Objective: To explore the methods of chromosome preparation in human peripheral blood and bone marrow after very high dose exposure and fit the dose-response curve of dicentrics and tings in the range of high doses over 6 Gy for estimating biological dose and detecting DNA damage in the victims of '10.21' accident. Methods: The samples of peripheral blood and bone marrow in 2 victims were collected to prepare chromosome mataphases and dicentrics (multicentrics) + rings were counted. The dose-response curve and equation of human blood irradiated between 6-22 Gy in vitro were established and applied to assess biological dose of 2 victims. In addition, their DNA damages were tested by alkaline single cell gel electrophoresis. Results: The dicentric + ring numbers of 4.47 per cell in victims B's peripheral blood lymphocytes and 9.15 per cell in victim A's bone marrow who had no mitosis in peripheral blood cell. The whole body average doses of victims B and A estimated by 6-22 Gy equation arrived at 9.4 Gy and 19.5 Gy, respectively. The serious DNA damages were expressed by small head and large tail comet figures. Conclusions: The biological doses of 2 victims estimated by 6-22 Gy dose-response curve have reached the levels of extreme grave bone marrow and intestinal ARS, respectively. (authors)

Estimation of dose in irradiated chicken bone by ESR method

International Nuclear Information System (INIS)

Tanabe, Hiroko; Hougetu, Daisuke

1998-01-01

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

Patient absorbed radiation doses estimation related to irradiation anatomy

International Nuclear Information System (INIS)

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

2014-01-01

Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector

Chest X ray effective doses estimation in computed radiography

International Nuclear Information System (INIS)

Abdalla, Esra Abdalrhman Dfaalla

2013-06-01

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

Estimation of effective dose equivalente from external irradiations

International Nuclear Information System (INIS)

Wakabayashi, T.

1985-07-01

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

Estimation of the Radon-induced Dose for Russia's Population: Methods and Results

International Nuclear Information System (INIS)

Marenny, A.M.; Savkin, M.N.; Shinkarev, S.M.

2000-01-01

A model is proposed for inferring the radon-induced annual average collective and personal doses, as well as the dose distribution of the population, all over Russia from selective radon monitoring in some regions of Russia. The model assumptions and the selective radon monitoring results that underlie the numerical estimates obtained for different population groups are presented. The current estimate of the collective radon-induced dose received by the population of Russia (148,100,000 as of 1996) is about 130,000 man Sv, of which 55,000 man Sv is for the rural population (27% of the total population) and 75,000 man Sv for the urban population (73% of the total). The average radon-induced personal dose in Russia is estimated to be about 0.87 mSv. About 1,000,000 people receive annual doses above 10 mSv, including some 200,000 people who receive doses above 20 mSv annually. The ways of making the current estimates more accurate are outlined. (author)

Simplification of an MCNP model designed for dose rate estimation

Directory of Open Access Journals (Sweden)

Laptev Alexander

2017-01-01

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

Estimation of inhalation doses from airborne releases using gross monitors

International Nuclear Information System (INIS)

Goldstein, N.P.

1978-01-01

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

The points for attention in retrospective personal dose estimate

International Nuclear Information System (INIS)

Wang Wuan

1994-01-01

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

Proof of concept and dose estimation with binary responses under model uncertainty.

Science.gov (United States)

Klingenberg, B

2009-01-30

This article suggests a unified framework for testing Proof of Concept (PoC) and estimating a target dose for the benefit of a more comprehensive, robust and powerful analysis in phase II or similar clinical trials. From a pre-specified set of candidate models, we choose the ones that best describe the observed dose-response. To decide which models, if any, significantly pick up a dose effect, we construct the permutation distribution of the minimum P-value over the candidate set. This allows us to find critical values and multiplicity adjusted P-values that control the familywise error rate of declaring any spurious effect in the candidate set as significant. Model averaging is then used to estimate a target dose. Popular single or multiple contrast tests for PoC, such as the Cochran-Armitage, Dunnett or Williams tests, are only optimal for specific dose-response shapes and do not provide target dose estimates with confidence limits. A thorough evaluation and comparison of our approach to these tests reveal that its power is as good or better in detecting a dose-response under various shapes with many more additional benefits: It incorporates model uncertainty in PoC decisions and target dose estimation, yields confidence intervals for target dose estimates and extends to more complicated data structures. We illustrate our method with the analysis of a Phase II clinical trial. Copyright (c) 2008 John Wiley & Sons, Ltd.

Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification (ADCI) and Dose Estimation.

Science.gov (United States)

Shirley, Ben; Li, Yanxin; Knoll, Joan H M; Rogan, Peter K

2017-09-04

Biological radiation dose can be estimated from dicentric chromosome frequencies in metaphase cells. Performing these cytogenetic dicentric chromosome assays is traditionally a manual, labor-intensive process not well suited to handle the volume of samples which may require examination in the wake of a mass casualty event. Automated Dicentric Chromosome Identifier and Dose Estimator (ADCI) software automates this process by examining sets of metaphase images using machine learning-based image processing techniques. The software selects appropriate images for analysis by removing unsuitable images, classifies each object as either a centromere-containing chromosome or non-chromosome, further distinguishes chromosomes as monocentric chromosomes (MCs) or dicentric chromosomes (DCs), determines DC frequency within a sample, and estimates biological radiation dose by comparing sample DC frequency with calibration curves computed using calibration samples. This protocol describes the usage of ADCI software. Typically, both calibration (known dose) and test (unknown dose) sets of metaphase images are imported to perform accurate dose estimation. Optimal images for analysis can be found automatically using preset image filters or can also be filtered through manual inspection. The software processes images within each sample and DC frequencies are computed at different levels of stringency for calling DCs, using a machine learning approach. Linear-quadratic calibration curves are generated based on DC frequencies in calibration samples exposed to known physical doses. Doses of test samples exposed to uncertain radiation levels are estimated from their DC frequencies using these calibration curves. Reports can be generated upon request and provide summary of results of one or more samples, of one or more calibration curves, or of dose estimation.

Homozygous mutation in the NPHP3 gene causing foetal nephronophthisis

DEFF Research Database (Denmark)

Abdullah, Uzma; Farooq, Muhammad; Fatima, Ambrin

2017-01-01

We present a case of a foetal sonographic finding of hyper-echogenic kidneys, which led to a strategic series of genetic tests and identified a homozygous mutation (c.424C > T, p. R142*) in the NPHP3 gene. Our study provides a rare presentation of NPHP3-related ciliopathy and adds to the mutation...

Assessment of uncertainties of external dose estimation after the Chernobyl accident

International Nuclear Information System (INIS)

Kruk, Julianna

2008-01-01

Full text: In the remote period of time after the Chernobyl accident the estimation of an external exposure with using of direct dose rate measurements or individual monitoring of inhabitants is rationally only for settlements where the preliminary estimation makes the range equal or greater 1.0 mSv per year. For inhabitancies of settlements where the preliminary estimation makes the range less 1.0 mSv per year the external dose is correctly to estimate by calculation. For the last cases the uncertainty should be assessed. The most accessible initial parameter for calculation of a dose of an external exposure is the average ground deposition of Cs-137 for the settlements. The character of density distribution of Cs-137 deposition in an area of one settlement is well enough studied. The best agreement of distribution of this parameter is reached with log-normal distribution practically for all settlements of the investigated territories with factor of a variation 0.3-0.6 and the standard geometrical deviation lying within the limits of 1.4-1.7. The dose factors which correspond to the structure of an available housing of settlement (type of apartment houses: wooden, stone, multi-storey) and age structure of the population are bring the main contribution into uncertainty of the external dose estimation. The situations with a different level of known information have been considered for the estimation of influence of those parameters on the general uncertainty. Thus the estimation of the uncertainty of the external dose was done for two variant: optimistic and pessimistic. In the optimistic case the estimation of external doses will be spent for specific settlement with known structure of housing and according to a known share of the living population in houses of the certain type. In that case, variability value dose factor will be limited to the chosen type of a residential building (for example - the one-storied wooden house), and a share of the living population

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

International Nuclear Information System (INIS)

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

1991-01-01

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

Estimation of doses to patients with chronic radiation sickness from external occupational exposure

International Nuclear Information System (INIS)

Jia Delin; Dai Guangfu

1991-01-01

The doses to patients with chronic radiation sickness who had engaged in diagnostic radiology have been estimated according to the radiation work load, type and capacity of X-ray equipment, protection conditions, data of nationwide survey on doses to X-ray workers in China, or the data of dose monitoring in working places. Based on the activities of radium sources, time taken up in performing radium therapy, distance to radium sources and radiation work load, the doses to patients who had engaged in radium therapy have been estimated. The results of estimated average doses for 29 cases of chronic radiation sickness are given. Their average red marrow dose, trunk dose and effective dose equivalent are 1.3 Gy, 1.2 Gy and 1.6 Sv, respectively

Hygienic estimation of population doses due to stratospheric fallout

International Nuclear Information System (INIS)

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

1980-01-01

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

Post-mortem magnetic resonance foetal imaging: a study of morphological correlation with conventional autopsy and histopathological findings.

Science.gov (United States)

Vullo, Annamaria; Panebianco, Valeria; Cannavale, Giuseppe; Aromatario, Mariarosaria; Cipolloni, Luigi; Frati, Paola; Santurro, Alessandro; Vullo, Francesco; Catalano, Carlo; Fineschi, Vittorio

2016-11-01

The aim of the present study is to offer our experience concerning post-mortem magnetic resonance (PMMR) in foetal death cases and an evaluation of the differences between the findings acquired by PMMR and by forensic autopsy. Fifteen foetuses were recruited from July 2014 to December 2015. These had suffered intrauterine death in women in the 21st to 38th week of gestation who were treated in the emergency department for non-perception of foetal movements. We performed a PMMR on foetuses, 3 ± 1 days on average from the time of death, and then a complete forensic autopsy was performed. All 15 foetuses were examined with a whole-body study protocol, starting from the skull, down to and including the lower limbs. The total time of examination ranged from 20 to 30 min in each case. The external evaluation and description of post-mortem phenomena (maceration), record of the weight and detection and the various measurements of foetal diameters were evaluated before performing autopsy. A complete histopathological study was performed in each case. Out of 15 cases examined, eight were negative for structural anatomical abnormalities and/or diseases, both in the preliminary radiological examination and the traditional autopsy. In the remaining seven cases, pathological findings were detected by PMMR with corresponding results at autopsy. PMMR can provide useful information on foetal medical conditions and result in improved diagnostic classification. It may enable the planning of a more suitable technique before proceeding to autopsy, including focusing on certain aspects of organ pathology otherwise not detectable. The association between PMMR, post-mortem examination and related histological study of the foetus-placenta unit could help reduce the percentage of cases in which the cause of foetal death remains unexplained. Lastly, it may allow a selective sampling of the organ in order to target histological investigations.

Evaluation of the foetal time to death in mice after application of direct and indirect euthanasia methods.

Science.gov (United States)

Muñoz-Mediavilla, C; Cámara, J A; Salazar, S; Segui, B; Sanguino, D; Mulero, F; de la Cueva, E; Blanco, I

2016-04-01

Directive 2010/63/EU on the protection of animals used for scientific purposes requires that the killing of mammal foetuses during the last third of their gestational period should be accomplished through effective and humane methods. The fact that murine foetuses are resistant to hypoxia-mediated euthanasia renders the current euthanasia methods ineffective or humane for the foetuses when these methods are applied to pregnant female mice. We have assessed the time to death of foetuses after performing either indirect (dam euthanasia) or direct (via intraplacental injection--a new approach to euthanasia) euthanasia methods in order to determine a euthanasia method that is appropriate, ethical and efficient for the killing of mouse foetuses. The respective times to death of foetuses after performing the three most commonly used euthanasia methods (namely cervical dislocation, CO2inhalation and intraperitoneal sodium pentobarbital administration) were recorded. Absence of foetal heartbeat was monitored via ultrasound. We consider that the most effective and humane method of foetal euthanasia was the one able to achieve foetal death within the shortest possible period of time. Among the indirect euthanasia methods assessed, the administration of a sodium pentobarbital overdose to pregnant female mice was found to be the fastest for foetuses, with an average post-treatment foetal death of approximately 29.8 min. As for the direct euthanasia method assessed, foetal time to death after intraplacental injection of sodium pentobarbital was approximately 14 min. Significant differences among the different mouse strains employed were found. Based on the results obtained in our study, we consider that the administration of a sodium pentobarbital overdose by intraplacental injection to be an effective euthanasia method for murine foetuses. © The Author(s) 2015.

Single point estimation of phenytoin dosing: a reappraisal.

Science.gov (United States)

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

1981-11-01

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

On the uncertainties in effective dose estimates of adult CT head scans

International Nuclear Information System (INIS)

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

2008-01-01

Estimates of the effective dose to adult patients from computed tomography (CT) head scanning can be calculated using a number of different methods. These estimates can be used for a variety of purposes, such as improving scanning protocols, comparing different CT imaging centers, and weighing the benefits of the scan against the risk of radiation-induced cancer. The question arises: What is the uncertainty in these effective dose estimates? This study calculates the uncertainty of effective dose estimates produced by three computer programs (CT-EXPO, CTDosimetry, and ImpactDose) and one method that makes use of dose-length product (DLP) values. Uncertainties were calculated in accordance with an internationally recognized uncertainty analysis guide. For each of the four methods, the smallest and largest overall uncertainties (stated at the 95% confidence interval) were: 20%-31% (CT-EXPO), 15%-28% (CTDosimetry), 20%-36% (ImpactDose), and 22%-32% (DLP), respectively. The overall uncertainties for each method vary due to differences in the uncertainties of factors used in each method. The smallest uncertainties apply when the CT dose index for the scanner has been measured using a calibrated pencil ionization chamber

Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

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Mokhtari-Dizaji, M.; Sharafi, A. A.; Larijani, B.; Mokhlesian, N.; Hasanzadeh, H. [Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

2008-04-15

Objective : The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. Materials and Methods : An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. Result : There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 {mu}Gy and 1.81 Gy, respectively. Also, the scan center dose in the women was 5.70 Gy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. Conclusion : We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry.

Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

International Nuclear Information System (INIS)

Mokhtari-Dizaji, M.; Sharafi, A. A.; Larijani, B.; Mokhlesian, N.; Hasanzadeh, H.

2008-01-01

Objective : The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. Materials and Methods : An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. Result : There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 μGy and 1.81 Gy, respectively. Also, the scan center dose in the women was 5.70 Gy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. Conclusion : We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry

An open-source framework for stress-testing non-invasive foetal ECG extraction algorithms.

Science.gov (United States)

Andreotti, Fernando; Behar, Joachim; Zaunseder, Sebastian; Oster, Julien; Clifford, Gari D

2016-05-01

Over the past decades, many studies have been published on the extraction of non-invasive foetal electrocardiogram (NI-FECG) from abdominal recordings. Most of these contributions claim to obtain excellent results in detecting foetal QRS (FQRS) complexes in terms of location. A small subset of authors have investigated the extraction of morphological features from the NI-FECG. However, due to the shortage of available public databases, the large variety of performance measures employed and the lack of open-source reference algorithms, most contributions cannot be meaningfully assessed. This article attempts to address these issues by presenting a standardised methodology for stress testing NI-FECG algorithms, including absolute data, as well as extraction and evaluation routines. To that end, a large database of realistic artificial signals was created, totaling 145.8 h of multichannel data and over one million FQRS complexes. An important characteristic of this dataset is the inclusion of several non-stationary events (e.g. foetal movements, uterine contractions and heart rate fluctuations) that are critical for evaluating extraction routines. To demonstrate our testing methodology, three classes of NI-FECG extraction algorithms were evaluated: blind source separation (BSS), template subtraction (TS) and adaptive methods (AM). Experiments were conducted to benchmark the performance of eight NI-FECG extraction algorithms on the artificial database focusing on: FQRS detection and morphological analysis (foetal QT and T/QRS ratio). The overall median FQRS detection accuracies (i.e. considering all non-stationary events) for the best performing methods in each group were 99.9% for BSS, 97.9% for AM and 96.0% for TS. Both FQRS detections and morphological parameters were shown to heavily depend on the extraction techniques and signal-to-noise ratio. Particularly, it is shown that their evaluation in the source domain, obtained after using a BSS technique, should be

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

International Nuclear Information System (INIS)

Bourgois, L.

2011-01-01

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

Potential combined effects of maternal smoking and coffee intake on foetal death within the Danish National Birth Cohort

DEFF Research Database (Denmark)

Morales-Suárez-Varela, Maria; Nohr, Ellen A; Olsen, Jørn

2018-01-01

on the risk of foetal (early and late) death. The study included 90 086 pregnant women, with information about their smoking habit and coffee intake in early pregnancy, and several potential confounding factors. Interaction was studied by calculating both the hazard ratio (HR) in Cox's regression (linear......Background: Several studies have linked coffee intake and smoking to foetal death, but a possible interaction between both exposures remains unknown. Methods: We studied, within the Danish National Birth Cohort, the potential interaction between smoking and coffee drinking while pregnant...... and smoothed restricted cubic spline) and the interaction contrast ratio (ICR). Results: Women who neither smoked nor drank coffee were used as the reference group. Drinking more than 3 cups/d of coffee was associated with the highest risk of foetal death, spontaneous abortion and stillbirth for all smoking...

Organ dose estimates for the Japanese atomic-bomb survivors

International Nuclear Information System (INIS)

Kerr, G.D.

1978-10-01

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

MODE OF DELIVERY AND FOETAL OUTCOME IN MECONIUM-STAINED LIQUOR: A RETROSPECTIVE STUDY

Directory of Open Access Journals (Sweden)

Anitha Narasimhaiah

2016-08-01

Full Text Available AIMS AND OBJECTIVES To study the incidence of MSL, mode of delivery and foetal outcome in women with MSL in labour. MATERIALS AND METHODS A retrospective study was conducted from January 2014 to December 2015 on patients admitted in labour room of Dr. B. R. Ambedkar Medical College and Hospital and assessed for MSL, mode of delivery and foetal outcome. RESULTS Out of the 1661 deliveries 195 (11.73 % were complicated with MSL. Chi square test was applied to analyse Grades of meconium and APGAR score at 95 % confidence and p value of < 0.05 was obtained which was statistically significant. CONCLUSION MSL alone is not an indication for Caesarean Section and is not associated with adverse neonatal outcome. Increase in the grades of MSL is associated with more adverse outcome.

Radiation dose estimates for carbon-11-labelled PET tracers

International Nuclear Information System (INIS)

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

2012-01-01

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

Estimates of effective dose in adult CT examinations

International Nuclear Information System (INIS)

Mohamed, Mustafa Awad Elhaj.

2015-12-01

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

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

Challenges in nourishing the intrauterine growth-restricted foetus - Lessons learned from studies in the intrauterine growth-restricted foetal sheep.

Science.gov (United States)

Hay, William W; Brown, Laura D; Rozance, Paul J; Wesolowski, Stephanie R; Limesand, Sean W

2016-08-01

Previous attempts to improve growth and development of the intrauterine growth-restricted (IUGR) foetus during pregnancy have not worked or caused harm. Our research identifies tissue-specific mechanisms underlying foetal growth restriction and then tests strategies to improve growth and ameliorate many of the metabolic problems before the infant is born. The goal of our studies is to reduce the impact of foetal growth restriction at critical stages of development on the lifelong complications of IUGR offspring. Defining specific mechanisms that cause growth restriction in the foetus might identify specific nutrients and hormones that could be given to the mother to improve foetal growth and reduce metabolic complications, using strategies first tested in our IUGR animal model. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Phthalate-Induced Pathology in the Foetal Testis Involves More Than Decreased Testosterone Production

Science.gov (United States)

Foetal exposure to phthalates is known to adversely impact male reproductive development and function. Developmental anomalies of reproductive tract have been attributed to impaired testosterone synthesis. However, species differences in the ability to produce testosterone have...

TU-H-207A-08: Estimating Radiation Dose From Low-Dose Lung Cancer Screening CT Exams Using Tube Current Modulation

International Nuclear Information System (INIS)

Hardy, A; Bostani, M; McMillan, K; Zankl, M; Cagnon, C; McNitt-Gray, M

2016-01-01

Purpose: The purpose of this work is to estimate effective and lung doses from a low-dose lung cancer screening CT protocol using Tube Current Modulation (TCM) across patient models of different sizes. Methods: Monte Carlo simulation methods were used to estimate effective and lung doses from a low-dose lung cancer screening protocol for a 64-slice CT (Sensation 64, Siemens Healthcare) that used TCM. Scanning parameters were from the AAPM protocols. Ten GSF voxelized patient models were used and had all radiosensitive organs identified to facilitate estimating both organ and effective doses. Predicted TCM schemes for each patient model were generated using a validated method wherein tissue attenuation characteristics and scanner limitations were used to determine the TCM output as a function of table position and source angle. The water equivalent diameter (WED) was determined by estimating the attenuation at the center of the scan volume for each patient model. Monte Carlo simulations were performed using the unique TCM scheme for each patient model. Lung doses were tallied and effective doses were estimated using ICRP 103 tissue weighting factors. Effective and lung dose values were normalized by scanspecific 32 cm CTDIvol values based upon the average tube current across the entire simulated scan. Absolute and normalized doses were reported as a function of WED for each patient. Results: For all ten patients modeled, the effective dose using TCM protocols was below 1.5 mSv. Smaller sized patient models experienced lower absolute doses compared to larger sized patients. Normalized effective and lung doses showed some dependence on patient size (R2 = 0.77 and 0.78, respectively). Conclusion: Effective doses for a low-dose lung screening protocol using TCM were below 1.5 mSv for all patient models used in this study. Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical

TU-H-207A-08: Estimating Radiation Dose From Low-Dose Lung Cancer Screening CT Exams Using Tube Current Modulation

Energy Technology Data Exchange (ETDEWEB)

Hardy, A; Bostani, M [University of California, Los Angeles, Los Angeles, CA (United States); McMillan, K [Mayo Clinic, Rochester, MN (United States); Zankl, M [Helmholtz Zentrum Munchen, Neuherberg (Germany); Cagnon, C [UCLA Medical Center, Los Angeles, CA (United States); McNitt-Gray, M [UCLA School of Medicine, Los Angeles, CA (United States)

2016-06-15

Purpose: The purpose of this work is to estimate effective and lung doses from a low-dose lung cancer screening CT protocol using Tube Current Modulation (TCM) across patient models of different sizes. Methods: Monte Carlo simulation methods were used to estimate effective and lung doses from a low-dose lung cancer screening protocol for a 64-slice CT (Sensation 64, Siemens Healthcare) that used TCM. Scanning parameters were from the AAPM protocols. Ten GSF voxelized patient models were used and had all radiosensitive organs identified to facilitate estimating both organ and effective doses. Predicted TCM schemes for each patient model were generated using a validated method wherein tissue attenuation characteristics and scanner limitations were used to determine the TCM output as a function of table position and source angle. The water equivalent diameter (WED) was determined by estimating the attenuation at the center of the scan volume for each patient model. Monte Carlo simulations were performed using the unique TCM scheme for each patient model. Lung doses were tallied and effective doses were estimated using ICRP 103 tissue weighting factors. Effective and lung dose values were normalized by scanspecific 32 cm CTDIvol values based upon the average tube current across the entire simulated scan. Absolute and normalized doses were reported as a function of WED for each patient. Results: For all ten patients modeled, the effective dose using TCM protocols was below 1.5 mSv. Smaller sized patient models experienced lower absolute doses compared to larger sized patients. Normalized effective and lung doses showed some dependence on patient size (R2 = 0.77 and 0.78, respectively). Conclusion: Effective doses for a low-dose lung screening protocol using TCM were below 1.5 mSv for all patient models used in this study. Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical

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

Science.gov (United States)

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

2011-03-01

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

Estimation of population doses from diagnostic medical examinations in Japan, 1974. IV. Dose estimation of fetus exposed in utero to diagnostic x rays

Energy Technology Data Exchange (ETDEWEB)

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

1976-07-01

In fetus exposed in utero to diagnostic x rays for the medical examinations of the mother, the absorbed dose has been estimated on the basis of a 1974 nation wide radiological survey. The results of the survey showed that the number of radiographs per year connected with pregnant women was 0.32 million for chest examination excluding mass surveys. 0.29 million for obstetrical examinations including pelvimetry, and 0.21 million for abdominal and pelvic examinations with a total of 0.82 million. The dose absorbed in the fetus was measured with an ionization chamber placed at the hypothetical center of the fetus in an ''average woman'' Rando phantom in which a maternal body was simulated by adding MixDp materials. ''The collective dose'' to the fetus in the pregnant women receiving a given type of examination was calculated from the number of radiographs per year connected with the pregnant women and the fetal doses. The percapita mean marrow dose (CMD), the leukemia significant dose (LSD) and the genetically significant dose (GSD) for the fetus were determined from the collective dose, taking into account the birth expectancy, the child expectancy, life expectancy and significant factor for the fetus. The collective dose to the fetus was estimated to be 9.3 x 10/sup 4/ man rad per year. The resultant values of CMD, LSD and GSD were 0.81 mrad per year, 0.79 mrad per person per year and 1.44 mrad per person per year, respectively.

Estimation of the total absorbed dose by quartz in retrospective conditions

International Nuclear Information System (INIS)

Correcher, V.; Delgado, A.

2003-01-01

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

A new approach to the estimation of radiopharmaceutical radiation dose distributions

International Nuclear Information System (INIS)

Hetherington, E.L.R.; Wood, N.R.

1975-03-01

For a photon energy of 150 keV, the Monte Carlo technique of photon history simulation was used to obtain estimates of the dose distribution in a human phantom for three activity distributions relevant to diagnostic nuclear medicine. In this preliminary work, the number of photon histories considered was insufficient to produce complete dose contours and the dose distributions are presented in the form of colour-coded diagrams. The distribution obtained illustrate an important deficiency in the MIRD Schema for dose estimation. Although the Schema uses the same mathematical technique for calculating photon doses, the results are obtained as average values for the whole body and for complete organs. It is shown that the actual dose distributions, particularly those for the whole body may, differ significantly from the average value calculated using the MIRD Schema and published absorbed fractions. (author)

Fetus dose estimation in thyroid cancer post-surgical radioiodine therapy

International Nuclear Information System (INIS)

Mianji, Fereidoun A.; Karimi Diba, Jila; Babakhani, Asad

2015-01-01

Unrecognised pregnancy during radioisotope therapy of thyroid cancer results in hardly definable embryo/fetus exposures, particularly when the thyroid gland is already removed. Sources of such difficulty include uncertainty in data like pregnancy commencing time, amount and distribution of metastasized thyroid cells in body, effect of the thyroidectomy on the fetus dose coefficient etc. Despite all these uncertainties, estimation of the order of the fetus dose in most cases is enough for medical and legal decision-making purposes. A model for adapting the dose coefficients recommended by the well-known methods to the problem of fetus dose assessment in athyrotic patients is proposed. The model defines a correction factor for the problem and ensures that the fetus dose in athyrotic pregnant patients is less than the normal patients. A case of pregnant patient undergone post-surgical therapy by I-131 is then studied for quantitative comparison of the methods. The results draw a range for the fetus dose in athyrotic patients using the derived factor. This reduces the concerns on under- or over-estimation of the embryo/fetus dose and is helpful for personal and/or legal decision-making on abortion. (authors)

Porcine foetal and neonatal CYP3A liver expression

Directory of Open Access Journals (Sweden)

Marie Louise Hiort Hermann

2011-05-01

Full Text Available Human cytochrome P450 3A7 (CYP3A7 and cytochrome P450 3A4 (CYP3A4 are hepatic metabolising enzymes which participates in the biotransformation of endo- and exogenous substances in foetuses and neonates respectively. These CYP3A enzymes display an inverse relationship: CYP3A7 is the dominant enzyme in the foetal liver, whereas the expression of CYP3A4 is low. After parturition there is a shift in the expression, thus CYP3A7 is down regulated, while the level of CYP3A4 gradually increases and becomes the dominant metabolising CYP3A enzyme in the adult. The minipig is increasingly being used as a model for humans in biomedical studies, because of its many similarities with the human physiology and anatomy. The aim of this study was to examine whether, as in humans, a shift is seen in the hepatic expression of a CYP3A7- like enzyme to cytochrome P450 3A29 (CYP3A29 (an orthologue to the human CYP3A4 in minipigs. This was elucidated by examining the hepatic mRNA expression of CYP3A7 and CYP3A29 in 39 foetuses and newborn Göttingen minipigs using quantitative real time polymerase chain reaction (qPCR. Furthermore the immunochemical level of CYP3A7-LE and CYP3A29 was measured in liver microsomes using western blotting. The expression of CYP3A29 was approximately 9- fold greater in neonates compared to foetuses, and a similar difference was reflected on the immunochemical level. It was not possible to detect a significant level of foetal CYP3A7 mRNA, but immunoblotting showed a visible difference depending on age. This study demonstrates an increase in the expression of CYP3A29, the CYP3A4 orthologue in perinatal minipigs as in humans, which suggests that the minipig could be a good model when testing for human foetal toxicity towards CYP3A4 substrates.

SU-E-T-86: A Systematic Method for GammaKnife SRS Fetal Dose Estimation

Energy Technology Data Exchange (ETDEWEB)

Geneser, S; Paulsson, A; Sneed, P; Braunstein, S; Ma, L [UCSF Comprehensive Cancer Center, San Francisco, CA (United States)

2015-06-15

Purpose: Estimating fetal dose is critical to the decision-making process when radiation treatment is indicated during pregnancy. Fetal doses less than 5cGy confer no measurable non-cancer developmental risks but can produce a threefold increase in developing childhood cancer. In this study, we estimate fetal dose for a patient receiving Gamma Knife stereotactic radiosurgery (GKSRS) treatment and develop a method to estimate dose directly from plan details. Methods: A patient underwent GKSRS on a Perfexion unit for eight brain metastases (two infratentorial and one brainstem). Dose measurements were performed using a CC13, head phantom, and solid water. Superficial doses to the thyroid, sternum, and pelvis were measured using MOSFETs during treatment. Because the fetal dose was too low to accurately measure, we obtained measurements proximally to the isocenter, fitted to an exponential function, and extrapolated dose to the fundus of the uterus, uterine midpoint, and pubic synthesis for both the preliminary and delivered plans. Results: The R-squared fit for the delivered doses was 0.995. The estimated fetal doses for the 72 minute preliminary and 138 minute delivered plans range from 0.0014 to 0.028cGy and 0.07 to 0.38cGy, respectively. MOSFET readings during treatment were just above background for the thyroid and negligible for all inferior positions. The method for estimating fetal dose from plan shot information was within 0.2cGy of the measured values at 14cm cranial to the fetal location. Conclusion: Estimated fetal doses for both the preliminary and delivered plan were well below the 5cGy recommended limit. Due to Pefexion shielding, internal dose is primarily governed by attenuation and drops off exponentially. This is the first work that reports fetal dose for a GK Perfexion unit. Although multiple lesions were treated and the duration of treatment was long, the estimated fetal dose remained very low.

SU-E-T-86: A Systematic Method for GammaKnife SRS Fetal Dose Estimation

International Nuclear Information System (INIS)

Geneser, S; Paulsson, A; Sneed, P; Braunstein, S; Ma, L

2015-01-01

Purpose: Estimating fetal dose is critical to the decision-making process when radiation treatment is indicated during pregnancy. Fetal doses less than 5cGy confer no measurable non-cancer developmental risks but can produce a threefold increase in developing childhood cancer. In this study, we estimate fetal dose for a patient receiving Gamma Knife stereotactic radiosurgery (GKSRS) treatment and develop a method to estimate dose directly from plan details. Methods: A patient underwent GKSRS on a Perfexion unit for eight brain metastases (two infratentorial and one brainstem). Dose measurements were performed using a CC13, head phantom, and solid water. Superficial doses to the thyroid, sternum, and pelvis were measured using MOSFETs during treatment. Because the fetal dose was too low to accurately measure, we obtained measurements proximally to the isocenter, fitted to an exponential function, and extrapolated dose to the fundus of the uterus, uterine midpoint, and pubic synthesis for both the preliminary and delivered plans. Results: The R-squared fit for the delivered doses was 0.995. The estimated fetal doses for the 72 minute preliminary and 138 minute delivered plans range from 0.0014 to 0.028cGy and 0.07 to 0.38cGy, respectively. MOSFET readings during treatment were just above background for the thyroid and negligible for all inferior positions. The method for estimating fetal dose from plan shot information was within 0.2cGy of the measured values at 14cm cranial to the fetal location. Conclusion: Estimated fetal doses for both the preliminary and delivered plan were well below the 5cGy recommended limit. Due to Pefexion shielding, internal dose is primarily governed by attenuation and drops off exponentially. This is the first work that reports fetal dose for a GK Perfexion unit. Although multiple lesions were treated and the duration of treatment was long, the estimated fetal dose remained very low

Aspects of pre-dose and other luminescence phenomena in quartz absorbed dose estimation

International Nuclear Information System (INIS)

Adamiec, G.

2000-01-01

The understanding of all luminescence processes occurring in quartz is of paramount importance in the further development of robust absorbed dose estimation techniques (for the purpose of dating and retrospective dosimetry). The findings presented in this thesis, aid future improvements of absorbed dose estimation techniques using quartz by presenting investigations in the following areas: 1) interpretation of measurement results, 2) numerical modelling of luminescence in quartz, 3) phenomena needing inclusion in future physical models of luminescence. In the first part, the variability of properties of single quartz grains is examined. Through empirical and theoretical considerations, investigations are made of various problems of measurements of luminescence using multi-grain aliquots, and specifically areas where the heterogeneity of the sample at the inter-grain level may be misinterpreted at the multi-grain-aliquot level. The results obtained suggest that the heterogeneity of samples is often overlooked, and that such differences can have a profound influence on the interpretation of measurement results. Discussed are the shape of TL glow curves, OSL decay curves, dose response curves (including consequences for using certain signals as proxies for others), normalisation procedures and D E estimation techniques. Further, a numerical model of luminescence is proposed, which includes multiple R-centres and is used to describe the pre-dose sensitisation in quartz. The numerical model exhibits a broad-scale behaviour observed experimentally in a sample of annealed quartz. The shapes of TAC for lower (20 Gy) and higher doses (1 kGy) and the evolution with temperature of the isothermal sensitisation curves are qualitatively matched for the empirical and numerical systems. In the third area, a preliminary investigation of the properties of the '110 deg. C peak' in the 550 nm emission band, in annealed quartz is presented. These properties are in sharp contrast with

Controversies and considerations regarding the termination of pregnancy for foetal anomalies in Islam.

Science.gov (United States)

Al-Matary, Abdulrahman; Ali, Jaffar

2014-02-05

Approximately one-fourth of all the inhabitants on earth are Muslims. Due to unprecedented migration, physicians are often confronted with cultures other than their own that adhere to different paradigms. In Islam, and most religions, abortion is forbidden. Islam is considerably liberal concerning abortion, which is dependent on (i) the threat of harm to mothers, (ii) the status of the pregnancy before or after ensoulment (on the 120th day of gestation), and (iii) the presence of foetal anomalies that are incompatible with life. Considerable variation in religious edicts exists, but most Islamic scholars agree that the termination of a pregnancy for foetal anomalies is allowed before ensoulment, after which abortion becomes totally forbidden, even in the presence of foetal abnormalities; the exception being a risk to the mother's life or confirmed intrauterine death. The authors urge Muslim law makers to also consider abortion post ensoulment if it is certain that the malformed foetus will decease soon after birth or will be severely malformed and physically and mentally incapacitated after birth to avoid substantial hardship that may continue for years for mothers and family members. The authors recommend that an institutional committee governed and monitored by a national committee make decisions pertaining to abortion to ensure that ethics are preserved and mistakes are prevented. Anomalous foetuses must be detected at the earliest possible time to enable an appropriate medical intervention prior to the 120th day.

Gluconeogenesis in rat placenta during foetal development

Energy Technology Data Exchange (ETDEWEB)

Bagewadikar, R S; Sharma, C; Nadkarni, G B [Bhabha Atomic Research Centre, Bombay (India). Biochemistry and Food Technology Div.

1977-01-01

Variations in glycogen levels in rat placenta have been correlated with gluconeogenesis in this tissue. Placental homogenate could synthesize substantial amounts of glucose from L-alanine-U-/sup 14/C in early pregnancy. This has been substantiated by the observed enhancement in the activities of glucose 6-phosphatase, fructose 1, 6-diphosphatase and phosphoenolpyruvate carboxykinase. Gluconeogenic activity in placenta could proceed till the foetal liver was able to take over this function. The increase or decrease in placental glycogen is concomitant with glycogen synthetase, but not phosphorylase, activity. The reversible catalytic properties of placental aldolase also show subtle functional changes during and late phases of gestation.

Gluconeogenesis in rat placenta during foetal development

International Nuclear Information System (INIS)

Bagewadikar, R.S.; Sharma, C.; Nadkarni, G.B.

1977-01-01

Variations in glycogen levels in rat placenta have been correlated with gluconeogenesis in this tissue. Placental homogenate could synthesize substantial amounts of glucose from L-alanine-U- 14 C in early pregnancy. This has been substantiated by the observed enhancement in the activities of glucose 6-phosphatase, fructose 1, 6-diphosphatase and phosphoenolpyruvate carboxykinase. Gluconeogenic activity in placenta could proceed till the foetal liver was able to take over this function. The increase or decrease in placental glycogen is concomitant with glycogen synthetase, but not phosphorylase, activity. The reversible catalytic properties of placental aldolase also show subtle functional changes during and late phases of gestation. (author)

Long-term effects of foetal undernutrition on intermediary metabolism in growing lambs

DEFF Research Database (Denmark)

Kiani, Ali; Nielsen, Mette Benedicte Olaf; Tauson, Anne-Helene

2011-01-01

The objective of this study was to investigate the effects of foetal undernutrition on the metabolism in growing lambs. Seven-month-old lambs whose nothers had been fed either restrictively (RN; n = 14) or adequately (AN; n = 6) in late gestation were fasted for three days. One hour before fasting......, IGF-I and leptin were not different between the two groups of lambs. Unexpectedly, at the end of the 3 d fasting, in spite of lower NEFA concentration (1.6 ± 0.03 vs. 1.9 ± 0.05 mM in Groups RN and AN, respectively), the BOHB concentration in RN lambs (0.94 ± 0.02 mM) was significantly higher than...... that in AN lambs (0.78 ± 0.04 mM). This higher rate of BOHB production might be interpreted as perturbations in etone body metabolism potentially induced by under-nutrition during foetal life. However, more investigations are necessary to clarify this interrelationship....

Optimizing CT radiation dose based on patient size and image quality: the size-specific dose estimate method

Energy Technology Data Exchange (ETDEWEB)

Larson, David B. [Stanford University School of Medicine, Department of Radiology, Stanford, CA (United States)

2014-10-15

The principle of ALARA (dose as low as reasonably achievable) calls for dose optimization rather than dose reduction, per se. Optimization of CT radiation dose is accomplished by producing images of acceptable diagnostic image quality using the lowest dose method available. Because it is image quality that constrains the dose, CT dose optimization is primarily a problem of image quality rather than radiation dose. Therefore, the primary focus in CT radiation dose optimization should be on image quality. However, no reliable direct measure of image quality has been developed for routine clinical practice. Until such measures become available, size-specific dose estimates (SSDE) can be used as a reasonable image-quality estimate. The SSDE method of radiation dose optimization for CT abdomen and pelvis consists of plotting SSDE for a sample of examinations as a function of patient size, establishing an SSDE threshold curve based on radiologists' assessment of image quality, and modifying protocols to consistently produce doses that are slightly above the threshold SSDE curve. Challenges in operationalizing CT radiation dose optimization include data gathering and monitoring, managing the complexities of the numerous protocols, scanners and operators, and understanding the relationship of the automated tube current modulation (ATCM) parameters to image quality. Because CT manufacturers currently maintain their ATCM algorithms as secret for proprietary reasons, prospective modeling of SSDE for patient populations is not possible without reverse engineering the ATCM algorithm and, hence, optimization by this method requires a trial-and-error approach. (orig.)

Foetal life protein restriction in male mink (Neovison vison) kits lowers post-weaning protein oxidation and the relative abundance of hepatic fructose-1,6-bisphosphatase mRNA

DEFF Research Database (Denmark)

Matthiesen, Connie Marianne Frank; Blache, D.; Thomsen, Preben Dybdahl

2012-01-01

Foetal life malnutrition has been studied intensively in a number of animal models. Results show that especially foetal life protein malnutrition can lead to metabolic changes later in life. This might be of particular importance for strict carnivores, for example, cat and mink (Neovison vison...... born to mothers fed either a low-protein diet (LP), that is, 14% of metabolizable energy (ME) from protein (foetal low – FL), n = 16, or an adequate-protein (AP) diet, that is, 29% of ME from protein (foetal adequate – FA), n = 16) in the last 16.3 ± 1.8 days of pregnancy were used. The FL offspring...... had lower birth weight and lower relative abundance of fructose-1,6-bisphosphatase (Fru-1,6-P2ase) and pyruvate kinase mRNA in foetal hepatic tissue than FA kits. The mothers were fed a diet containing adequate protein until weaning. At weaning (7 weeks of age), half of the kits from each foetal...

Development of the methodology for estimation of dose from a source

International Nuclear Information System (INIS)

Golebaone, E.M.

2012-04-01

The geometry of a source plays an important role when determining which method to apply in order to accurately estimate dose from a source. If wrong source geometry is used the dose received may be underestimated or overestimated therefore this may lead to wrong decision in dealing with the exposure situation. In this project moisture density gauge was used to represent a point source in order to demonstrate the key parameters to be used when estimating dose from point source. The parameters to be considered are activity of the source, the ambient dose rate, gamma constant for the radionuclide, as well as the transport index on the package of the source. The distance from the source, and the time spent in the radiation field must be known in order to calculate the dose. (author)

An African Thought on the Ethics of Human Foetal Life | Ebeh ...

African Journals Online (AJOL)

This paper presents an African thought on the ethics of human foetal life and this can be discussed against the backdrop of the African concept of life, person and community. In the process, it examines the fact of humanity and personhood of the human foetus and the role of the community in the determinant of humanity and ...

Estimation of Absorbed Dose in Occlusal Radiography

International Nuclear Information System (INIS)

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

1990-01-01

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

An estimate of the doubling dose of ionizing radiation for humans

International Nuclear Information System (INIS)

Neel, J.V.

1990-01-01

All accumulated data on the children of Hiroshima and Nagasaki survivors have been analyzed employing the revised procedures for estimating gonadal radiation exposures that became effective in 1986. The basic statistical procedure employed has been to obtain a linear regression of indicator on the combined gonadal exposures of the parents. There is no statistically significant regression of indicator on dose for any of the indicators; however, it is accepted that some mutations were produced in the survivors of the bombings. The implications of the data for the genetic doubling dose of radiation for humans have been explored. The appropriate dose rate factor to be applied in extrapolating to the effect of chronic radiation is 2. This leads to a doubling dose estimate for the chronic irradiation of humans of between 3.4 and 4.5 Sv. The error is large but indeterminate, but the estimate is based on conservative assumptions. (3 tabs.)

Dose estimation by biological methods

International Nuclear Information System (INIS)

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

1997-01-01

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

RADTRAD: A simplified model for RADionuclide Transport and Removal And Dose estimation

International Nuclear Information System (INIS)

Humphreys, S.L.; Miller, L.A.; Monroe, D.K.; Heames, T.J.

1998-04-01

This report documents the RADTRAD computer code developed for the U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Reactor Regulation (NRR) to estimate transport and removal of radionuclides and dose at selected receptors. The document includes a users' guide to the code, a description of the technical basis for the code, the quality assurance and code acceptance testing documentation, and a programmers' guide. The RADTRAD code can be used to estimate the containment release using either the NRC TID-14844 or NUREG-1465 source terms and assumptions, or a user-specified table. In addition, the code can account for a reduction in the quantity of radioactive material due to containment sprays, natural deposition, filters, and other natural and engineered safety features. The RADTRAD code uses a combination of tables and/or numerical models of source term reduction phenomena to determine the time-dependent dose at user-specified locations for a given accident scenario. The code system also provides the inventory, decay chain, and dose conversion factor tables needed for the dose calculation. The RADTRAD code can be used to assess occupational radiation exposures, typically in the control room; to estimate site boundary doses; and to estimate dose attenuation due to modification of a facility or accident sequence

Estimation of Dose Received in Decommissioning of Phosphate Acid Factory-Petro Kimia Gresik

International Nuclear Information System (INIS)

Lubis, Erwansyah; Heru Umbara; Agus Gindo S

2007-01-01

The estimation of dose received in decommissioning of Phosphate Acid Factory-Petro Kimia Gresik (PAF-PKG) was carried out. The external dose estimated base on the radiation rate in each working area of zona-1, 2, 3 and 4. The internal dose estimated base on the radionuclides activity and diameter of particulate exist in each working area. The calculation of the internal dose was carried out by LUDEP 2.0 computer code. The results indicated that in the normal activity of decommissioning, the effective dose will received by the worker per year were 0.27 mSv in zona-1, 1.23 mSv in zona-2, 1.37 mSv in zona-3 and 11.85 mSv in zona-4. The internal dose received when a worse accident happens in decommissioning activity is 21.06 mSv for lung organ or 4.2 % of the dose limit for that organ. Based on the discussion above, indicated that in the decommissioning of PAF-PKG the dose received by the workers is far lower than the dose limit. (author)

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

International Nuclear Information System (INIS)

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

2004-01-01

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

A cross-cultural study on surrogate mother's empathy and maternal-foetal attachment.

Science.gov (United States)

Lorenceau, Ellen Schenkel; Mazzucca, Luis; Tisseron, Serge; Pizitz, Todd D

2015-06-01

Traditional and gestational surrogate mothers assist infertile couples by carrying their children. In 2005, a meta-analysis on surrogacy was conducted but no study had examined empathy and maternal-foetal attachment of surrogate mothers. Assessments of surrogate mothers show no sign of psychopathology, but one study showed differences on several MMPI-2 scales compared to a normative sample: surrogate mothers identified with stereotypically masculine traits such as assertiveness and competition. They had a higher self-esteem and lower levels of anxiety and depression. To determine if there is a difference in empathy and maternal-foetal attachment of surrogate mothers compared to a comparison group of mothers. Three groups of European traditional and gestational surrogate mothers (n=10), Anglo-Saxon traditional and gestational surrogate mothers (n=34) and a European normative sample of mothers (n=32) completed four published psychometric instruments: the Interpersonal Reactivity Index (empathy index), the Hospital Anxiety and Depressions Scale and the MC20, a social desirability scale. Pregnant surrogate mothers filled the Maternal Antenatal Attachment Scale (n=11). Statistical non-parametric analyses of variance were conducted. Depending on cultural background, surrogate mothers present differences in terms of empathy, anxiety and depression, social desirability and quality of attachment to the foetus compared to a normative sample. Environment plays a role for traditional and gestational surrogacy. Surrogate mothers of both groups are less anxious and depressed than normative samples. Maternal-foetal attachment is strong with a slightly lower quality of attachment. Surrogate mother's empathy indexes are similar to normative samples, sometimes higher. Copyright © 2014 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Estimate of dose in interventional radiology: a study of cases

International Nuclear Information System (INIS)

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

2006-01-01

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

Cytogenetic biological dosimetry. Dose estimative in accidental exposure

International Nuclear Information System (INIS)

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

1988-01-01

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

Foetal Alcohol Spectrum Disorders and Alterations in Brain and Behaviour

OpenAIRE

Guerri, Consuelo; Bazinet, Alissa; Riley, Edward P.

2009-01-01

The term ‘Foetal Alcohol Spectrum Disorders (FASD)’ refers to the range of disabilities that may result from prenatal alcohol exposure. This article reviews the effects of ethanol on the developing brain and its long-term structural and neurobehavioural consequences. Brain imaging, neurobehavioural and experimental studies demonstrate the devastating consequences of prenatal alcohol exposure on the developing central nervous system (CNS), identifying specific brain regions affected, the range...

Estimation of frequency, population doses and stochastic risks in brachytherapy in Japan, 1983

International Nuclear Information System (INIS)

Maruyama, Takashi; Kumamoto, Yoshikazu; Noda, Yutaka; Nishizawa, Kanae; Furuya, Yoshiro; Iwai, Kazuo.

1988-01-01

Based on the replies to a questionnaire distributed throughout Japan in 1983, genetically significant dose (GSD), per Caput mean bone marrow dose (CMD), leukemogenically significant dose (LSD), malignantly significant dose (MSD), and per Caput effective dose equivalent (EDE) from using small sealed radiation sources for radiotherapy were estimated. Annual frequencies of brachytherapy were estimated to be 2.6 x 10 3 for men and 36.3 x 10 3 for women, with a total of 38.9 x 10 3 . The annual frequencies of using afterloading technique were 0.3 x 10 3 for men and 18.8 x 10 3 for women, with a total of 19.1 x 10 3 . The annual population doses per person were 7.9 nGy for GSD, 118 μGy for CMD, 19.3 μGy for LSD, 172 μGy for MSD, and 428 μGy for EDE. The annual collective effective dose equivalent was estimated to be 5.13 x 10 4 man Sv. (Namekawa, K.)

Estimated collective effective dose to the population from nuclear medicine examinations in Slovenia

International Nuclear Information System (INIS)

Skrk, Damijan; Zontar, Dejan

2013-01-01

A national survey of patient exposure from nuclear medicine diagnostic procedures was performed by Slovenian Radiation Protection Administration in order to estimate their contribution to the collective effective dose to the population of Slovenia. A set of 36 examinations with the highest contributions to the collective effective dose was identified. Data about frequencies and average administered activities of radioisotopes used for those examinations were collected from all nuclear medicine departments in Slovenia. A collective effective dose to the population and an effective dose per capita were estimated from the collected data using dose conversion factors. The total collective effective dose to the population from nuclear medicine diagnostic procedures in 2011 was estimated to 102 manSv, giving an effective dose per capita of 0.05 mSv. The comparison of results of this study with studies performed in other countries indicates that the nuclear medicine providers in Slovenia are well aware of the importance of patient protection measures and of optimisation of procedures

Necessary accuracy of dose estimation during cohort epidemiologic study after irradiation

International Nuclear Information System (INIS)

Orlov, M.Yu.; Stepanenko, V.F.; Khoshi, M.; Takada, Dzh.

2003-01-01

Effect of breadth of dose ranges on values of radiation risk was estimated. Ratios of observed numbers of mortalities because of leukemia in the cohort in 1950 - 1974 under deferent radiation dose to expected number of mortalities in this cohort only under background radiation were used as degree of risk. Data of cooperative Japan-American Program LSS (Life Span Study) were applied in the researches. It is established that required for the risk assessment with uncertainty 20 - 30 % the accuracy of dose estimation comprises 30 - 35 % in the range 1 - 5 rad and 5 - 10 % in the range 5 - 30 rad [ru

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

STUDY OF MORPHOMETRIC CHANGES OF FOETAL STOMACH

Directory of Open Access Journals (Sweden)

Mohammed Aneesur Rahman

2017-07-01

Full Text Available BACKGROUND Interest in human development is very widespread largely because of the curiosity about our beginnings and desire to improve the quality of life. Understanding of the processes involved in the formation of various organs and systems has unrevealed most cryptic secrets of the nature. Human development begins at fertilisation when a male gamete or sperm unites with a female gamete or oocyte to form a single cell, a zygote. With the formation of zygote (single-celled stage, foetal development begins. The aim of the study is to- 1 Study the morphometric parameters of foetal stomach at various gestational ages. 2 Compare these observations with the previous studies. MATERIALS AND METHODS Present work was the cross-sectional study carried out in the Department of Anatomy in collaboration with the Department of Obstetrics and Gynaecology at SRTRGMC and Hospital, Ambajogai Dist., Beed, Maharashtra. For this, approval of Institutional Ethical Committee was taken. 30 aborted human foetuses of different age groups ranging from 12 to 36 weeks of fertilisation were taken from the Department of OB-GYN. Foetuses were preserved by using 10% formalin. Age of foetuses were determined by crown-rump length and history given by mother. Foetuses were dissected after preservation for 15 days and morphometric studies were done on stomach. RESULTS Various quantitative parameters like weight of foetus, crown-rump length, total length of stomach, weight of stomach, length of greater curvature, lesser curvature, width of cardia and width of pylorus were used. For the purpose of study and comparison with other researchers, the foetuses were divided into 3 groups. Morphometric changes were observed in different groups and compared with previous studies. CONCLUSION With the increase in the body weight, crown-rump length and gestational age of the foetus, there is gradual increase on various parameters of stomach.

The utilization of health care services by children with Foetal Alcohol Syndrome in the Western Cape, South Africa.

Science.gov (United States)

Credé, Sarah; Sinanovic, Edina; Adnams, Colleen; London, Leslie

2011-06-01

The rates of Foetal Alcohol Syndrome (FAS) and Partial Foetal Alcohol Spectrum (PFAS) in South Africa are the highest reported worldwide. There is a paucity of research examining the health care costs of caring for children with FAS or PFAS in this country. A cross-sectional analytical study was conducted using an interviewer-administered questionnaire amongst caregivers of children (0-12 years) with FAS/PFAS in the Western Cape to estimate the utilization of health care services; the annual direct and indirect health care costs per child as well as the total cost to society for providing health care services to children with FAS/PFAS. It was found that the median number of annual visits to public health care facilities per child was 8 (IQR 4 to 14). The total average annual cost per child was $1039.38 (95% CI: $808.68; $1270.07) and the total annual societal cost for the Western Cape was $70,960,053.68 (95% CI: $5,528,895.48; $86,709,971.13). Caregivers in receipt of a social support grant reported spending significantly less on health care for a child with FAS/PFAS (Fisher's exact p=0.004). These study results confirm the significant burden of FAS/PFAS on the Western Cape economy and the health care system which has significant implications for FAS prevention. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

ESTIMATION OF THE CONVERSION COEFFICIENTS FROM DOSE-AREA PRODUCT TO EFFECTIVE DOSE FOR BARIUM MEAL EXAMINATIONS FOR ADULT PATIENTS

Directory of Open Access Journals (Sweden)

A. V. Vodovatov

2018-01-01

Full Text Available Fluoroscopic examinations of the upper gastro-intestinal tract and, especially, barium meal examinations, are commonly performed in a majority of hospitals. These examinations are associated both with substantial individual patient doses and contribution to the collective dose from medical exposure. Effective dose estimation for this type of examinations is complicated due to: 1 the necessity to simulate the moving X-ray irradiation field; 2 differences in study structure for the individual patients; 3 subjectivity of the operators; and 4 differences in the X-ray equipment. The aim of the current study was to estimate conversion coefficients from dose-area product to effective dose for barium meal examinations for the over couch and under couch exposure conditions. The study was based on data collected in the X-ray unit of the surgical department of the St-Petersburg Mariinsky hospital. A model of patient exposure during barium meal examination was developed based on the collected data on fluoroscopy protocols and adult patient irradiation geometry. Conversion coefficients were calculated using PCXMC 2.0 software. Complete examinations were converted into a set of typical fluoroscopy phases and X-ray images, specified by the examined anatomical region and the projection of patient exposure. Conversion coefficients from dose-area product to effective dose were calculated for each phase of the examination and for the complete examination. The resulting values of the conversion coefficients are comparable with published data. Variations in the absolute values of the conversion coefficients can be explained by differences in clinical protocols, models for the estimation of the effective dose and parameters of barium meal examinations. The proposed approach for estimation of effective dose considers such important features of fluoroscopic examinations as: 1 non-uniform structure of examination, 2 significant movement of the X-ray tube within a single

Estimating adolescent sleep need using dose-response modeling.

Science.gov (United States)

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

2018-04-01

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

Maxine: A spreadsheet for estimating dose from chronic atmospheric radioactive releases

Energy Technology Data Exchange (ETDEWEB)

Jannik, Tim [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Bell, Evaleigh [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Dixon, Kenneth [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-07-24

MAXINE is an EXCEL© spreadsheet, which is used to estimate dose to individuals for routine and accidental atmospheric releases of radioactive materials. MAXINE does not contain an atmospheric dispersion model, but rather doses are estimated using air and ground concentrations as input. Minimal input is required to run the program and site specific parameters are used when possible. Complete code description, verification of models, and user’s manual have been included.

Stem cells from foetal adnexa and fluid in domestic animals: an update on their features and clinical application.

Science.gov (United States)

Iacono, E; Rossi, B; Merlo, B

2015-06-01

Over the past decade, stem cell research has emerged as an area of major interest for its potential in regenerative medicine applications. This is in constant need of new cell sources to conceive regenerative medicine approaches for diseases that are still without therapy. Scientists drew the attention towards alternative sources such as foetal adnexa and fluid, as these sources possess many advantages: first of all, cells can be extracted from discarded foetal material and it is non-invasive and inexpensive for the patient; secondly, abundant stem cells can be obtained; and finally, these stem cell sources are free from ethical considerations. Cells derived from foetal adnexa and fluid preserve some of the characteristics of the primitive embryonic layers from which they originate. Many studies have demonstrated the differentiation potential in vitro and in vivo towards mesenchymal and non-mesenchymal cell types; in addition, the immune-modulatory properties make these cells a good candidate for allo- and xenotransplantation. Naturally occurring diseases in domestic animals can be more ideal as disease model of human genetic and acquired diseases and could help to define the potential therapeutic use efficiency and safety of stem cells therapies. This review offers an update on the state of the art of characterization of domestic animals' MSCs derived from foetal adnexa and fluid and on the latest findings in pre-clinical or clinical setting of the stem cell populations isolated from these sources. © 2015 Blackwell Verlag GmbH.

A perspective on dose limits and biological effects of radiation on the foetus

International Nuclear Information System (INIS)

Myers, D.K.; Gordon, K.

1992-01-01

The potential biological effects of radiation doses to pregnant workers consistent with Canadian regulations and ICRP recommendations are reviewed. These hazards are in general very small compared to the normal hazards associated with human development. Potential carcinogenic effects may well be the major biological problem associated with foetal exposures. Radiation hazards to the embryo are essentially zero for exposures occurring during the first four weeks after conception. The new ICRP recommendations on exposures of pregnant women suggest a number of problems to be solved. These include (a) improvements in current methods of measuring both external radiation doses and intakes of certain radionuclides in Canada, (b) further research on the metabolism of radionuclides in pregnant women, including concentrations of certain radionuclides in foetal/embryonic tissues and also in adjacent tissues of the mother; and (c) socio-economic problems that may be involved in the implementation of the recommendations on exposures of pregnant workers, particularly in small facilities such as nuclear medicine departments in hospitals. (Author) 3 tabs., 21 refs

Testicular dysgenesis syndrome: foetal origin of adult reproductive problems

DEFF Research Database (Denmark)

Wohlfahrt-Veje, Christine; Main, Katharina M; Skakkebaek, Niels Erik

2009-01-01

, the risk of testis cancer is significantly increased in men with cryptorchidism and/or infertility. Several recent studies point towards early dysgenesis of the foetal testis as the biological link between these disorders. Dysgenesis has been demonstrated in biopsies of the contralateral testis of men...... with testis cancer and in infertile men. The histological evidence includes immature seminiferous tubules with undifferentiated Sertoli cells, microliths and Sertoli-cell only tubules. Dysgenetic testes often have an irregular ultrasound pattern, where microliths may also be visible. Our current hypothesis...

Do Thyroid Disrupting Chemicals Influence Foetal Development during Pregnancy?

DEFF Research Database (Denmark)

Hartoft-Nielsen, Marie-Louise; Boas, Malene; Bliddal, Sofie

2011-01-01

Maternal euthyroidism during pregnancy is crucial for normal development and, in particular, neurodevelopment of the foetus. Up to 3.5 percent of pregnant women suffer from hypothyroidism. Industrial use of various chemicals-endocrine disrupting chemicals (EDCs)-has been shown to cause almost...... constant exposure of humans with possible harmful influence on health and hormone regulation. EDCs may affect thyroid hormone homeostasis by different mechanisms, and though the effect of each chemical seems scarce, the added effects may cause inappropriate consequences on, for example, foetal...

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

International Nuclear Information System (INIS)

Hoppe, Michael E.; Schmidt, Taly Gilat

2012-01-01

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

Phantom measurements and computed estimates of breast dose with radiotherapy for Hodgkin's lymphoma: dose reduction with the use of the involved field

International Nuclear Information System (INIS)

Wirth, A.; Kron, T.; Sorell, G.; Cramb, J.; Wittwer, H.; Sullivan, K.

2008-01-01

Full text: The risk of breast cancer following radiotherapy for Hodgkin's lymphoma appears to be dose related. In this study we compared breast dose in an anthropomorphic phantom for conventional 'mantle'; upper mediastinal/bilateral neck (minimantle) and unilateral neck fields, and evaluated the accuracy of computer planned dose estimates for out-of-field doses. For each field, computer-planned breast dose (CPD) estimates were compared with thermolu-minescence dosimetry measurements in five locations within 'breast tissue'. CPD were also compared with ion chamber measurements in a slab phantom. Measured dose and CPD were within 20% of each other up to approximately 10 cm from the field edge. Beyond 10 cm, the CPD underestimated dose by a factor of 2 or more. The minimantle reduced the breast dose by a factor of approximately 10 compared with the mantle treatment. Treating the neck field lowered the breast dose by a further 50% or more. Modern involved-field radiotherapy for lymphoma substantially reduces breast dose compared with mantle fields. Computer dosimetery underestimated dose at larger distances from the field. This needs to be considered if computer dosimetery is used to estimate breast dose and, by extrapolation, breast cancer risk.

Dose-response curve estimation: a semiparametric mixture approach.

Science.gov (United States)

Yuan, Ying; Yin, Guosheng

2011-12-01

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

A study on pre-heat conditions in equivalent-dose estimation of holocene loess using single-aliquot regenerative-dose (SAR) protocol

International Nuclear Information System (INIS)

Jia Yaofeng; Huang Chunchang; Pang Jiangli; Lu Xinwei; Zhang Xu

2007-01-01

Through various arrangements of pre-heat and cut-heat temperatures in the equivalent-dose estimation of Holocene loess using a Double-SAR dating protocol, the paper estimated the equivalent-doses from several loess samples by application of IRSL and Post-IR OSL signals, respectively. The measured results present that the equivalent-dose depends on the heat temperature, especially depends on the cut-heat temperature, showing the equivalent-dose increases with the cut-heat temperature; a plateau of equivalent-dose appears at the 200-300 degree C preheat temperatures and the 200-240 degree C cut-heat temperatures, furthermore, the equivalent-doses estimated by IRSL and Post-IR OSL signals respectively are close to each other, which resulted from the similar sensitivity change directions of optical stimulated signals and their smaller change ranges in the measurement cycles using the various temperatures of pre-heat and cut-heat. This suggests that the 200-300 degree C pre-heat temperatures and the 200-240 degree C cut-heat temperatures are fit for dating young Holocene loess samples. (authors)

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Estimation of dose in dental radiology exams in critical regions

International Nuclear Information System (INIS)

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

2005-01-01

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

Uncertainties in estimating heart doses from 2D-tangential breast cancer radiotherapy

DEFF Research Database (Denmark)

Laugaard Lorenzen, Ebbe; Brink, Carsten; Taylor, Carolyn W.

2016-01-01

BACKGROUND AND PURPOSE: We evaluated the accuracy of three methods of estimating radiation dose to the heart from two-dimensional tangential radiotherapy for breast cancer, as used in Denmark during 1982-2002. MATERIAL AND METHODS: Three tangential radiotherapy regimens were reconstructed using CT......-based planning scans for 40 patients with left-sided and 10 with right-sided breast cancer. Setup errors and organ motion were simulated using estimated uncertainties. For left-sided patients, mean heart dose was related to maximum heart distance in the medial field. RESULTS: For left-sided breast cancer, mean...... to the uncertainty of estimates based on individual CT-scans. For right-sided breast cancer patients, mean heart dose based on individual CT-scans was always

Uncertainties in effective dose estimates of adult CT head scans: The effect of head size

International Nuclear Information System (INIS)

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

2009-01-01

Purpose: This study is an extension of a previous study where the uncertainties in effective dose estimates from adult CT head scans were calculated using four CT effective dose estimation methods, three of which were computer programs (CT-EXPO, CTDOSIMETRY, and IMPACTDOSE) and one that involved the dose length product (DLP). However, that study did not include the uncertainty contribution due to variations in head sizes. Methods: The uncertainties due to head size variations were estimated by first using the computer program data to calculate doses to small and large heads. These doses were then compared with doses calculated for the phantom heads used by the computer programs. An uncertainty was then assigned based on the difference between the small and large head doses and the doses of the phantom heads. Results: The uncertainties due to head size variations alone were found to be between 4% and 26% depending on the method used and the patient gender. When these uncertainties were included with the results of the previous study, the overall uncertainties in effective dose estimates (stated at the 95% confidence interval) were 20%-31% (CT-EXPO), 15%-30% (CTDOSIMETRY), 20%-36% (IMPACTDOSE), and 31%-40% (DLP). Conclusions: For the computer programs, the lower overall uncertainties were still achieved when measured values of CT dose index were used rather than tabulated values. For DLP dose estimates, head size variations made the largest (for males) and second largest (for females) contributions to effective dose uncertainty. An improvement in the uncertainty of the DLP method dose estimates will be achieved if head size variation can be taken into account.

Uncertainties in effective dose estimates of adult CT head scans: The effect of head size

Energy Technology Data Exchange (ETDEWEB)

Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E. [Department of Medical Physics, Royal Adelaide Hospital, Adelaide, South Australia 5000 (Australia) and School of Electrical and Information Engineering (Applied Physics), University of South Australia, Mawson Lakes, South Australia 5095 (Australia); Division of Medical Imaging, Women' s and Children' s Hospital, North Adelaide, South Australia 5006 (Australia) and School of Electrical and Information Engineering (Applied Physics), University of South Australia, Mawson Lakes, South Australia 5095 (Australia); School of Electrical and Information Engineering (Applied Physics), University of South Australia, Mawson Lakes, South Australia 5095 (Australia)

2009-09-15

Purpose: This study is an extension of a previous study where the uncertainties in effective dose estimates from adult CT head scans were calculated using four CT effective dose estimation methods, three of which were computer programs (CT-EXPO, CTDOSIMETRY, and IMPACTDOSE) and one that involved the dose length product (DLP). However, that study did not include the uncertainty contribution due to variations in head sizes. Methods: The uncertainties due to head size variations were estimated by first using the computer program data to calculate doses to small and large heads. These doses were then compared with doses calculated for the phantom heads used by the computer programs. An uncertainty was then assigned based on the difference between the small and large head doses and the doses of the phantom heads. Results: The uncertainties due to head size variations alone were found to be between 4% and 26% depending on the method used and the patient gender. When these uncertainties were included with the results of the previous study, the overall uncertainties in effective dose estimates (stated at the 95% confidence interval) were 20%-31% (CT-EXPO), 15%-30% (CTDOSIMETRY), 20%-36% (IMPACTDOSE), and 31%-40% (DLP). Conclusions: For the computer programs, the lower overall uncertainties were still achieved when measured values of CT dose index were used rather than tabulated values. For DLP dose estimates, head size variations made the largest (for males) and second largest (for females) contributions to effective dose uncertainty. An improvement in the uncertainty of the DLP method dose estimates will be achieved if head size variation can be taken into account.

GARDEC, Estimation of dose-rates reduction by garden decontamination

International Nuclear Information System (INIS)

Togawa, Orihiko

2006-01-01

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

The relationship between maternal body composition in early pregnancy and foetal mid-thigh soft-tissue thickness in the third trimester in a high-risk obstetric population.

Science.gov (United States)

Anglim, Breffini; Farah, Nadine; O'Connor, Clare; Daly, Niamh; Kennelly, Mairead M; Turner, Michael J

2017-07-01

Maternal obesity is an emerging challenge in contemporary obstetrics. To date there has been no study analysing the relationship between specific maternal body composition measurements and foetal soft-tissue measurements. The aim of this study was to determine whether measurement of maternal body composition at booking predicts foetal soft-tissue trajectories in the third trimester. We analysed the relationship between foetal thigh in the third trimester and both maternal BMI and body composition using the Tanita digital scales in the first trimester. Foetal subcutaneous thigh tissue measurements were obtained at intervals of 28, 32 and 36 weeks of gestation. A total of 160 women were identified. There was a direct correlation between MTST at 36 weeks and BMI (p = .002). There was a positive correlation between MTST at 36 weeks and leg fat mass (p = .13) and leg fat free mass (p = .013). There was a positive correlation between arm fat free mass and MTST at 36 weeks. We showed there is an association between maternal fat distribution and foetal subcutaneous thigh tissue measurements. MTST may be more useful in determining if a child is at risk of macrosomia. Impact statement Previous studies have suggested that maternal obesity programmes intrauterine foetal adiposity and growth. The aim of this study was to examine the relationship in a high-risk obstetric population between measurements of maternal body composition in early pregnancy and the assessment of foetal adiposity in the third trimester using serial ultrasound measurements of mid-thigh soft-tissue thickness. BMI is only a surrogate measurement of fat and does not measure fat distribution. Our study shows the distribution of both maternal fat and fat-free mass in early pregnancy may be positively associated with foetal soft-tissue measurements in the third trimester. Maternal arthropometric measurements other than BMI may help predict babies at risk of macrosomia and neonatal adiposity.

Analysis of data on radon monitoring and dose estimates for uranium mines

International Nuclear Information System (INIS)

Khan, A.H.; Srivastava, G.K.; Jha, Shankar; Sagar, D.V.

1994-01-01

Radon progeny are the major contributors to the radiation dose to uranium miners. Monitoring for radon and gamma radiation is an integral part of radiation protection in such mines. Data for equilibrium equivalent radon and the estimated mean annual doses are presented in this paper for Jaduguda uranium mine from 1986 to 1992. The 1992 data for Jaduguda and Bhatin mines are compared. The average annual effective dose for uranium miners is estimated at around 15.5 mSv. (author). 1 ref., 2 figs

External dose estimates for future Bikini Atoll inhabitants

International Nuclear Information System (INIS)

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

1976-01-01

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

Deterministic absorbed dose estimation in computed tomography using a discrete ordinates method

International Nuclear Information System (INIS)

Norris, Edward T.; Liu, Xin; Hsieh, Jiang

2015-01-01

Purpose: Organ dose estimation for a patient undergoing computed tomography (CT) scanning is very important. Although Monte Carlo methods are considered gold-standard in patient dose estimation, the computation time required is formidable for routine clinical calculations. Here, the authors instigate a deterministic method for estimating an absorbed dose more efficiently. Methods: Compared with current Monte Carlo methods, a more efficient approach to estimating the absorbed dose is to solve the linear Boltzmann equation numerically. In this study, an axial CT scan was modeled with a software package, Denovo, which solved the linear Boltzmann equation using the discrete ordinates method. The CT scanning configuration included 16 x-ray source positions, beam collimators, flat filters, and bowtie filters. The phantom was the standard 32 cm CT dose index (CTDI) phantom. Four different Denovo simulations were performed with different simulation parameters, including the number of quadrature sets and the order of Legendre polynomial expansions. A Monte Carlo simulation was also performed for benchmarking the Denovo simulations. A quantitative comparison was made of the simulation results obtained by the Denovo and the Monte Carlo methods. Results: The difference in the simulation results of the discrete ordinates method and those of the Monte Carlo methods was found to be small, with a root-mean-square difference of around 2.4%. It was found that the discrete ordinates method, with a higher order of Legendre polynomial expansions, underestimated the absorbed dose near the center of the phantom (i.e., low dose region). Simulations of the quadrature set 8 and the first order of the Legendre polynomial expansions proved to be the most efficient computation method in the authors’ study. The single-thread computation time of the deterministic simulation of the quadrature set 8 and the first order of the Legendre polynomial expansions was 21 min on a personal computer

The estimation of effective doses using measurement of several relevant physical parameters from radon exposures

International Nuclear Information System (INIS)

Ridzikova, A; Fronka, A.; Maly, B.; Moucka, L.

2003-01-01

In the present investigation, we will be study the dose relevant factors from continual monitoring in real homes into account getting more accurate estimation of 222 Rn the effective dose. The dose relevant parameters include the radon concentration, the equilibrium factor (f), the fraction (fp) of unattached radon decay products and real time occupancy people in home. The result of the measurement are the time courses of radon concentration that are based on estimation effective doses together with assessment of the real time occupancy people indoor. We found out by analysis that year effective dose is lower than effective dose estimated by ICRP recommendation from the integral measurement that included only average radon concentration. Our analysis of estimation effective doses using measurement of several physical parameters was made only in one case and for the better specification is important to measure in different real occupancy houses. (authors)

Development of mathematical model for estimation of entrance surface dose in mammography

International Nuclear Information System (INIS)

Abdelgani, Yassir Mohammed Tahir

2013-05-01

Computer simulation is a convenient and frequently used tool in the study of x-ray mammography, for the design of novel detector systems, the evaluation of dose deposition, x-ray technique optimization, and other applications. An important component in the simulation process is the accurate computer generation of x-ray spectra. A computer model for the generation of x-ray spectra in the mammographic energy rang from 18 keV to 40 ke V has been developed by Boone et al. Due to the lack of QC and dose measurement tools, in addition to unavailability of medical physics, a mathematical tool was developed for estimation of patient exposure and entrance dose. The proposed model require no assumptions concerning the physics of x-ray production in an x-ray tube, but rather makes use of x-ray spectra recently measured experimentally by John M Boone (Department of Radiology, University of California). Using experimental dose measurements for specific tube voltage and tube current the generated x-ray spectra were calibrated. The spectrum calibration factors show a tube voltage dependency. From the calibrated x-ray spectrum, the exposure and entrance dose were estimated for different k Vp and m A. Results show good agreement between the measured and estimated values for tube voltage between 18 to 45 k Vp with a good correlation of nearly 1 and equal slope. The maximum estimated different between the measured and the simulated dose is approximately equal to 0.07%.(Author)

Revision of risk estimates and implications for dose limits

International Nuclear Information System (INIS)

Clarke, R.H.

1989-01-01

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

The study on pre-heat conditions in the equivalent-dose estimation of holocene loess using the single-aliquot regenerative-dose (SAR) protocol

International Nuclear Information System (INIS)

Jia Yaofeng; Huang Chunchang; Pang Jiangli; Lu Xinwei; Zhang Xu

2008-01-01

The thermal treatment in the equivalent-dose estimation often is carried in the OSL dating, and pre-heat is a main thermal treatment. Due to which will originate the problems of thermal transfer and thermal activation, the thermal treatment and the setup of their conditions are key problems influencing the accuracy of OSL dating. The paper combined the temperature of pre-heat and cut-heat used in the routine measurement of IRSL and Post-IR OSL, and then estimated the equivalent-dose of several loess samples. The estimated result presents that the equivalent-dose depends on the heat temperature, especially depends on the cut-heat temperature, which is to say that the equivalent-dose increases with the cut-heat temperature; a plateau of equivalent-dose appears when using the 200-240 degree C cut-heat in the range of 200-300 degree C pre-heat, and the equivalent-doses estimated by IRSL and Post-IR OSL respectively are close to each other, which resulted from the similar sensitivity change direction of optical stimulated signals and its smaller change range in the measurement cycles using the combined temperature of pre- heat and cut-heat, and the incomplete calibration of sensitivity change of optical stimulated signals in the whole measurement cycles caused the variation of estimated equivalent-dose corresponding to the cut-heat temperature. (authors)

Okadaic acid for radiation dose estimation using drug-induced premature chromosome condensation

International Nuclear Information System (INIS)

Wang Chunyan; Zhang Wei; Su Xu

2005-01-01

Objective: To establish simple biological method for high irradiation dose estimation using drug-induced prematurely condensed chromosomes (PCC) aberrations. Methods: Peripheral blood was taken from healthy adults and irradiated by 0, 1, 2, 5, 10, 15, 20 and 25 Gy 60 Co γ-rays. Then the blood samples were cultured for 48 hrs. One hr before the end of culture , okadaic acid was added into culture medium to induce PCC rings, which were counted for each dose point. Results: The yield of PCC rings was increased with the dose of radiation until 20 Gy. Within the range of 1 to 20 Gy, there was a good dose-response relationship between the yield of PCC rings and radiation dose. Conclusion: Compared with the analysis of frequency of dicentrics, the yield of PCC rings could be a good biodosimetry indicator for estimation of high dose irradiation. (authors)

Estimation of eye absorbed doses in head & neck radiotherapy practices using thermoluminescent detectors

Directory of Open Access Journals (Sweden)

Gh Bagheri

2011-09-01

Full Text Available  Determination of eye absorbed dose during head & neck radiotherapy is essential to estimate the risk of cataract. Dose measurements were made in 20 head & neck cancer patients undergoing 60Co radiotherapy using LiF(MCP thermoluminescent dosimeters. Head & neck cancer radiotherapy was delivered by fields using SAD & SSD techniques. For each patient, 3 TLD chips were placed on each eye. Head & neck dose was about 700-6000 cGy in 8-28 equal fractions. The range of eye dose is estimated to be (3.49-639.1 mGy with a mean of maximum dose (98.114 mGy, which is about 3 % of head & neck dose. Maximum eye dose was observed for distsnces of about 3 cm from edge of the field to eye.

Estimation of absorbed dose by newborn patients subjected to chest radiographs

International Nuclear Information System (INIS)

Bunick, Ana P.; Schelin, Hugo R.; Denyak, Valeriy

2016-01-01

The aim of this study is to present an estimate of the effective dose received by newborn patients hospitalized in NICU and subjected to X-ray examinations of the chest in the AP projection. Initially, were followed examinations chest X-rays performed on newborn patients and subsequently, simulated in a newborn simulator object. The ESAK values obtained by TLDs were used to calculate the effective dose obtained at each examination by Caldose_X software. The estimated values for the effective dose in the simulated exams in this study range from 2,3μSv the 10,7μSv. The results achieved are, generally, inferior to those reported for similar previous studies. (author)

Estimation of effective doses in pediatric X-ray computed tomography examination.

Science.gov (United States)

Obara, Hideki; Takahashi, Midori; Kudou, Kazuya; Mariya, Yasushi; Takai, Yoshihiro; Kashiwakura, Ikuo

2017-11-01

X-ray computed tomography (CT) images are used for diagnostic and therapeutic purposes in various medical disciplines. In Japan, the number of facilities that own diagnostic CT equipment, the number of CT examinations and the number of CT scanners increased by ~1.4-fold between 2005 and 2011. CT operators (medical radiological technologists, medical physicists and physicians) must understand the effective doses for examinations at their own institutions and carefully approach each examination. In addition, the patients undergoing the examination (as well as his/her family) must understand the effective dose of each examination in the context of the cumulative dose. In the present study, the numbers of pediatric patients (aged 0-5 years) and total patients who underwent CT at Hirosaki University Hospital (Hirosaki, Japan) between January 2011 and December 2013 were surveyed, and effective doses administered to children aged 0, 1 and 5 years were evaluated. Age- and region-specific conversion factors and dose-length products obtained from the CT scanner were used to estimate the effective doses. The numbers of CT examinations performed in 2011, 2012 and 2013 were 16,662, 17,491 and 17,649, respectively, of which 613 (1.2%) of the overall total involved children aged 0-5 years. The estimated effective doses per examination to children aged 0, 1 and 5 years were 6.3±4.8, 4.9±3.8 and 2.7±3.0 mSv, respectively. This large variation was attributed to several factors associated with scan methods and ranges in actual setting. In conclusion, the requirement for individual patient prospective exposure management systems and estimations of low-dose radiation exposure should be considered in light of the harmful effects of exposure.

Simple approximation for estimating centerline gamma absorbed dose rates due to a continuous Gaussian plume

International Nuclear Information System (INIS)

Overcamp, T.J.; Fjeld, R.A.

1987-01-01

A simple approximation for estimating the centerline gamma absorbed dose rates due to a continuous Gaussian plume was developed. To simplify the integration of the dose integral, this approach makes use of the Gaussian cloud concentration distribution. The solution is expressed in terms of the I1 and I2 integrals which were developed for estimating long-term dose due to a sector-averaged Gaussian plume. Estimates of tissue absorbed dose rates for the new approach and for the uniform cloud model were compared to numerical integration of the dose integral over a Gaussian plume distribution

Radiation dose estimates for copper-64 citrate in man

International Nuclear Information System (INIS)

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

1985-01-01

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

Radiation dose estimates for copper-64 citrate in man

International Nuclear Information System (INIS)

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

1986-01-01

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

Developing milk industry estimates for dose reconstruction projects

International Nuclear Information System (INIS)

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

1991-01-01

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

Dose estimation of interventional cardiologists in different body regions

International Nuclear Information System (INIS)

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

2015-01-01

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

Estimation of the collective dose in the Portuguese population due to medical procedures in 2010

International Nuclear Information System (INIS)

Teles, Pedro; Vaz, Pedro; Sousa, M. Carmen de; Paulo, Graciano; Santos, Joana; Pascoal, Ana; Cardoso, Gabriela; Santos, Ana Isabel; Lanca, Isabel; Matela, Nuno; Janeiro, Luis; Sousa, Patrick; Carvoeiras, Pedro; Parafita, Rui; Simaozinho, Paula

2013-01-01

In a wide range of medical fields, technological advancements have led to an increase in the average collective dose in national populations worldwide. Periodic estimations of the average collective population dose due to medical exposure is, therefore of utmost importance, and is now mandatory in countries within the European Union (article 12 of EURATOM directive 97/ 43). Presented in this work is a report on the estimation of the collective dose in the Portuguese population due to nuclear medicine diagnostic procedures and the Top 20 diagnostic radiology examinations, which represent the 20 exams that contribute the most to the total collective dose in diagnostic radiology and interventional procedures in Europe. This work involved the collaboration of a multidisciplinary taskforce comprising representatives of all major Portuguese stakeholders (universities, research institutions, public and private health care providers, administrative services of the National Healthcare System, scientific and professional associations and private service providers). This allowed us to gather a comprehensive amount of data necessary for a robust estimation of the collective effective dose to the Portuguese population. The methodology used for data collection and dose estimation was based on European Commission recommendations, as this work was performed in the framework of the European wide Dose Datamed II project. This is the first study estimating the collective dose for the population in Portugal, considering such a wide national coverage and range of procedures and consisting of important baseline reference data. The taskforce intends to continue developing periodic collective dose estimations in the future. The estimated annual average effective dose for the Portuguese population was of 0.080±0.017 mSv caput -1 for nuclear medicine exams and of 0.96±0.68 mSv caput -1 for the Top 20 diagnostic radiology exams. (authors)

FATAL FOETAL ABNORMALITY, IRISH CONSTITUTIONAL LAW, AND MELLET v IRELAND.

Science.gov (United States)

de Londras, Fiona

2016-12-27

Under the Irish Constitution abortion is allowed only where the life of the pregnant woman is at risk. The provision in question, Article 40.3.3 (or the 8th Amendment) has long been criticised for failing to respect women's autonomy, and in Mellet v Ireland, the UN Human Rights Committee found that Amanda Jane Mellet, who travelled to Liverpool to access abortion following a finding that her foetus suffered a fatal abnormality, had suffered a violation of her rights under the International Covenant on Civil and Political Rights (ICCPR). In this commentary I demonstrate the value of Mellet when compared to the possible legal findings in such circumstances under both the Constitution and the European Convention on Human Rights, and argue that the findings are not restricted to cases of fatal foetal abnormality. Rather, the Committee's decision illustrates the suffering that all women in Ireland who travel to access abortion experience, arguably constituting a violation of their right to be free from cruel, inhuman, and degrading treatment. On that reading, Mellet signifies the need to implement a comprehensive rethink of Irish abortion law including, but going beyond, access to abortion in cases of fatal foetal abnormality. © The Author 2016. Published by Oxford University Press; all rights reserved. For Permissions, please email: journals.permissions@oup.com.

Estimation of internal dose from radiocesium and phantom

International Nuclear Information System (INIS)

Uchiyama, Masafumi; Nakamura, Yuji

1994-01-01

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

Cytogenetical dose estimation for 3 severely exposed patients in the JCO criticality accident in Tokai-mura

International Nuclear Information System (INIS)

Hayata, Isamu; Kanda, Reiko; Minamihisamatsu, Masako; Furukawa, Akira; Sasaki, Masao S.

2001-01-01

A dose estimation by chromosome analysis was performed on the 3 severely exposed patients in the Tokai-mura criticality accident. Drastically reduced lymphocyte counts suggested that the whole-body dose of radiation which they had been exposed to was unprecedentedly high. Because the number of lymphocytes in the white blood cells in two patients was very low, we could not culture and harvest cells by the conventional method. To collect the number of lymphocytes necessary for chromosome preparation, we processed blood samples by a modified method, called the high-yield chromosome preparation method. With this technique, we could culture and harvest cells, and then make air-dried chromosome slides. We applied a new dose-estimation method involving an artificially induced prematurely condensed ring chromosome, the PCC-ring method, to estimate an unusually high dose with a short time. The estimated doses by the PCC-ring method were in fairly good accordance with those by the conventional dicentric and ring chromosome (Dic + R) method. The biologically estimated dose was comparable with that estimated by a physical method. As far as we know, the estimated dose of the most severely exposed patient in the present study is the highest recorded among that chromosome analyses have been able to estimate in humans. (author)

Using optically stimulated electrons from quartz for the estimation of natural doses

DEFF Research Database (Denmark)

Ankjærgaard, Christina; Murray, A.S.; Denby, Phil M.

2009-01-01

A flow-through Geiger-Müller pancake electron detector attachment has been fitted to a standard Risø TL/OSL reader enabling optically stimulated electrons (OSE) to be measured simultaneously with optically stimulated luminescence (OSL). Using this detector, OSE and OSL measurements from natural......, a dose recovery test shows that OSE can successfully recover a laboratory dose of 300 Gy given before any laboratory thermal treatment, for preheating temperatures between 160 and 260 °C. Furthermore, for the first time natural OSE decay curves are detected and these signals are used to estimate a burial...... dose using the single-aliquot regenerative-dose (SAR) procedure. Finally, a comparative study of the equivalent doses estimated using both OSE and OSL from 10 quartz samples are presented, and it is shown that OSE has a significant potential in retrospective dosimetry....

Estimation of 1945 to 1957 food consumption. Hanford Environmental Dose Reconstruction Project

Energy Technology Data Exchange (ETDEWEB)

Anderson, D.M.; Bates, D.J.; Marsh, T.L.

1993-07-01

This report details the methods used and the results of the study on the estimated historic levels of food consumption by individuals in the Hanford Environmental Dose Reconstruction (HEDR) study area from 1945--1957. This period includes the time of highest releases from Hanford and is the period for which data are being collected in the Hanford Thyroid Disease Study. These estimates provide the food-consumption inputs for the HEDR database of individual diets. This database will be an input file in the Hanford Environmental Dose Reconstruction Integrated Code (HEDRIC) computer model that will be used to calculate the radiation dose. The report focuses on fresh milk, eggs, lettuce, and spinach. These foods were chosen because they have been found to be significant contributors to radiation dose based on the Technical Steering Panel dose decision level.

Cardiac dose estimates from Danish and Swedish breast cancer radiotherapy during 1977-2001

International Nuclear Information System (INIS)

Taylor, Carolyn W.; Bronnum, Dorthe; Darby, Sarah C.; Gagliardi, Giovanna; Hall, Per; Jensen, Maj-Britt; McGale, Paul; Nisbet, Andrew; Ewertz, Marianne

2011-01-01

Background and purpose: To estimate target and cardiac doses from breast cancer radiotherapy in Denmark and in the Stockholm and Umea areas of Sweden during 1977-2001. Methods: Representative samples of irradiated women were identified from the databases of the Danish Breast Cancer Cooperative Group and the Swedish Nationwide Cancer Registry. Virtual simulation, computed tomography planning and manual planning were used to reconstruct radiotherapy regimens on a typical woman. Estimates of target dose and various measures of cardiac dose were derived from individual radiotherapy charts. Results: Doses were estimated in 681 Danish and 130 Swedish women. Mean heart dose for individual women varied from 1.6 to 14.9 Gray in Denmark and from 1.2 to 22.1 Gray in Sweden. In Denmark, mean target doses averaged across women increased from 40.6 to 53.8 Gray during 1977-2001 but, despite this, mean heart dose averaged across women remained around 6 Gy for left-sided and 2-3 Gray for right-sided radiotherapy. In Sweden mean target dose averaged across women increased from 38.7 to 46.6 Gray during 1977-2001, while mean heart dose averaged across women decreased from 12.0 to 7.3 Gray for left-sided and from 3.6 to 3.2 Gray for right-sided radiotherapy. Temporal trends for mean biologically effective dose [BED] to the heart, mean dose to the left anterior descending coronary artery, the right coronary artery and the circumflex coronary artery were broadly similar. Conclusions: Cardiac doses in Denmark were low relative to those in Sweden. In both countries, target dose increased during 1977-2001. Despite this, cardiac doses remained constant in Denmark and decreased in Sweden.

Comparing different methods for estimating radiation dose to the conceptus

Energy Technology Data Exchange (ETDEWEB)

Lopez-Rendon, X.; Dedulle, A. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); Walgraeve, M.S.; Woussen, S.; Zhang, G. [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Bosmans, H. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Zanca, F. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); GE Healthcare, Buc (France)

2017-02-15

To compare different methods available in the literature for estimating radiation dose to the conceptus (D{sub conceptus}) against a patient-specific Monte Carlo (MC) simulation and a commercial software package (CSP). Eight voxel models from abdominopelvic CT exams of pregnant patients were generated. D{sub conceptus} was calculated with an MC framework including patient-specific longitudinal tube current modulation (TCM). For the same patients, dose to the uterus, D{sub uterus}, was calculated as an alternative for D{sub conceptus}, with a CSP that uses a standard-size, non-pregnant phantom and a generic TCM curve. The percentage error between D{sub uterus} and D{sub conceptus} was studied. Dose to the conceptus and percent error with respect to D{sub conceptus} was also estimated for three methods in the literature. The percentage error ranged from -15.9% to 40.0% when comparing MC to CSP. When comparing the TCM profiles with the generic TCM profile from the CSP, differences were observed due to patient habitus and conceptus position. For the other methods, the percentage error ranged from -30.1% to 13.5% but applicability was limited. Estimating an accurate D{sub conceptus} requires a patient-specific approach that the CSP investigated cannot provide. Available methods in the literature can provide a better estimation if applicable to patient-specific cases. (orig.)

Estimating average glandular dose by measuring glandular rate in mammograms

International Nuclear Information System (INIS)

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

2003-01-01

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

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

International Nuclear Information System (INIS)

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

1989-01-01

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

Ladtap XL Version 2017: A Spreadsheet For Estimating Dose Resulting From Aqueous Releases

Energy Technology Data Exchange (ETDEWEB)

Minter, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jannik, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-06-15

LADTAP XL© is an EXCEL© spreadsheet used to estimate dose to offsite individuals and populations resulting from routine and accidental releases of radioactive materials to the Savannah River. LADTAP XL© contains two worksheets: LADTAP and IRRIDOSE. The LADTAP worksheet estimates dose for environmental pathways including external exposure resulting from recreational activities on the Savannah River and internal exposure resulting from ingestion of water, fish, and invertebrates originating from the Savannah River. IRRIDOSE estimates offsite dose to individuals and populations from irrigation of foodstuffs with contaminated water from the Savannah River. In 2004, a complete description of the LADTAP XL© code and an associated user’s manual was documented in LADTAP XL©: A Spreadsheet for Estimating Dose Resulting from Aqueous Release (WSRC-TR-2004-00059) and revised input parameters, dose coefficients, and radionuclide decay constants were incorporated into LADTAP XL© Version 2013 (SRNL-STI-2011-00238). LADTAP XL© Version 2017 is a slight modification to Version 2013 with minor changes made for more user-friendly parameter inputs and organization, updates in the time conversion factors used within the dose calculations, and fixed an issue with the expected time build-up parameter referenced within the population shoreline dose calculations. This manual has been produced to update the code description, verification of the models, and provide an updated user’s manual. LADTAP XL© Version 2017 has been verified by Minter (2017) and is ready for use at the Savannah River Site (SRS).

Dose estimates in a loss of lead shielding truck accident.

Energy Technology Data Exchange (ETDEWEB)

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

2009-08-01

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

Estimation of effective dose for children in interventional cardiology

Directory of Open Access Journals (Sweden)

S. S. Sarycheva

2017-01-01

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

Coincidence in the dose estimation in a OEP by different methods

International Nuclear Information System (INIS)

Guerrero C, C.; Arceo M, C.; Brena V, M.

2007-01-01

The case of an apparent overexposure to radiation according to that indicated for the thermoluminescent dosemeter 81.59 mSv (TLD) of a occupationally exposed hard-working (POE), for that was practiced the study of biological dosimetry. The estimated dose was 0.12 Gy with which was proven the marked dose registration by the TLD dosemeter. It was concluded that both doses are the same ones. (Author)

The Change of Perinatal Mortality Over Three Decades in a Reference Centre in the Aegean Region: Neonatal Mortality has decreased but Foetal Mortality Remains Unchanged

Directory of Open Access Journals (Sweden)

Nilgün Kültürsay

2017-12-01

Full Text Available Background: Perinatal, foetal and neonatal mortality statistics are important to show the development of a health care system in a country. However, in our country there are very few national and regional data about the changing pattern of perinatal neonatal mortality along with the development of new technologies in this area. Aims: Evaluation of the changes in mortality rates and the causes of perinatal and neonatal deaths within years in a perinatal reference centre which serves a high-risk population. Study Design: Cross-sectional retrospective study. Methods: The perinatal, neonatal and foetal mortality rates in the years 1979-1980 (1st time point and 1988-1989 (2nd time point were compared with the year 2008 (3rd time point. The causes of mortality were assessed by Wigglesworth classification and death reports. The neonatal mortality in the neonatal intensive care unit was also calculated. Results: Foetal mortality rates were 44/1000, 31.4/1000 and 41.75/1000 births, perinatal mortality rates were 35.6/1000, 18.8/1000 and 9/1000 births, and neonatal mortality rates were 35.6/1000, 18.8/1000 and 9/1000 live births for the three study time points, respectively. The mortality rate in neonatal intensive care unit decreased consistently from 33%, to 22.6% and 10%, respectively, together with decreasing neonatal mortality rates. The causes of perinatal deaths were foetal death 85%, immaturity 4%, and lethal congenital malformations 8% according to Wigglesworth classification in 2008, showing the high impact of foetal deaths on this high perinatal mortality rate. Infectious causes of neonatal deaths decreased but congenital anomalies increased in the last decades. Conclusion: Although neonatal mortality rate decreased significantly; foetal mortality rate has stayed unchanged since the late eighties. In order to decrease foetal and perinatal mortality rates more efficiently, reducing consanguineous marriages and providing better antenatal care for

Estimates of radiation doses and cancer risk from food intake in Korea

International Nuclear Information System (INIS)

Moon, Eun Kyeong; Lee, Won Jin; Ha, Wi Ho; Seo, Song Won; Jin, Young Woo; Jeong, Kyu Hwan; Yoon, Hae Jung; Kim, Hyoung Soo; Hwang, Myung Sil; Choi, Hoon

2016-01-01

After the Fukushima Daiichi nuclear power plant accident, a widespread public concern for radiation exposure through the contamination of domestic or imported food has continued worldwide. Because the internal exposure from contaminated food is an important consideration for human health effect, some studies for estimating radiation doses and cancer risk from the Fukushima nuclear accident have been conducted in several countries (1). The aims of the study is to estimate internal radiation dose and lifetime risks of cancer from food ingestion in Korean population. Our findings suggest no discernible increase n radiation doses or excess fatal cancer risk from food ingestion at this stage in Korea, and provide scientific evidence of the risk communication with general public associated with low-dose radiation exposure.

Estimates of radiation doses and cancer risk from food intake in Korea

Energy Technology Data Exchange (ETDEWEB)

Moon, Eun Kyeong; Lee, Won Jin [Korea University, Seoul (Korea, Republic of); Ha, Wi Ho; Seo, Song Won; Jin, Young Woo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Jeong, Kyu Hwan [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Yoon, Hae Jung; Kim, Hyoung Soo; Hwang, Myung Sil [Ministry of Food and Drug Safety, Cheongju (Korea, Republic of); Choi, Hoon [Wonkwang University, Iksan (Korea, Republic of)

2016-04-15

After the Fukushima Daiichi nuclear power plant accident, a widespread public concern for radiation exposure through the contamination of domestic or imported food has continued worldwide. Because the internal exposure from contaminated food is an important consideration for human health effect, some studies for estimating radiation doses and cancer risk from the Fukushima nuclear accident have been conducted in several countries (1). The aims of the study is to estimate internal radiation dose and lifetime risks of cancer from food ingestion in Korean population. Our findings suggest no discernible increase n radiation doses or excess fatal cancer risk from food ingestion at this stage in Korea, and provide scientific evidence of the risk communication with general public associated with low-dose radiation exposure.

Estimation of the absorbed dose in radiation-processed food. Pt.2

International Nuclear Information System (INIS)

Desrosiers, M.F.

1991-01-01

The use of electron paramagnetic resonance spectroscopy to accurately evaluate the absorbed dose to radiation-processed bones (and thus meats) is examined. Additive re-irradiation of the bone produces a reproducible response function which can be used to evaluate the initial dose by back-extrapolation. It was found that an exponential fit (vs linear or polynomial) to the data provides improved accuracy of the estimated dose. These data as well as the protocol for the additive dose method are presented. (author)

Inhibition of PIM1 kinase attenuates inflammation-induced pro-labour mediators in human foetal membranes in vitro.

Science.gov (United States)

Lim, Ratana; Barker, Gillian; Lappas, Martha

2017-06-01

Does proviral integration site for Moloney murine leukaemic virus (PIM)1 kinase play a role in regulating the inflammatory processes of human labour and delivery? PIM1 kinase plays a critical role in foetal membranes in regulating pro-inflammatory and pro-labour mediators. Infection and inflammation have strong causal links to preterm delivery by stimulating pro-inflammatory cytokines and collagen degrading enzymes, which can lead to rupture of membranes. PIM1 has been shown to have a role in immune regulation and inflammation in non-gestational tissues; however, its role has not been explored in the field of human labour. PIM1 expression was analysed in myometrium and/or foetal membranes obtained at term and preterm (n = 8-9 patients per group). Foetal membranes, freshly isolated amnion cells and primary myometrial cells were used to investigate the effect of PIM1 inhibition on pro-labour mediators (n = 5 patients per treatment group). Foetal membranes, from term and preterm, were obtained from non-labouring and labouring women, and from preterm pre-labour rupture of membranes (PPROM) (n = 9 per group). Amnion was collected from women with and without preterm chorioamnionitis (n = 8 per group). Expression of PIM1 kinase was determined by qRT-PCR and western blotting. To determine the effect of PIM1 kinase inhibition on the expression of pro-inflammatory and pro-labour mediators induced by bacterial products lipopolysaccharide (LPS) (10 μg/ml) and flagellin (1 μg/ml) and pro-inflammatory cytokine tumour necrosis factor (TNF) (10 ng/ml), chemical inhibitors SMI-4a (20 μM) and AZD1208 (50 μM) were used in foetal membrane explants and siRNA against PIM1 was used in primary amnion cells. Statistical significance was set at P membranes after spontaneous term labour compared to no labour at term and in amnion with preterm chorioamnionitis compared to preterm with no chorioamnionitis. There was no change in PIM1 expression with preterm labour or PPROM

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

International Nuclear Information System (INIS)

Weir, V; Zhang, J

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-06-15

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

Dose estimation from food intake due to the Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

Yamaguchi, Ichiro; Terada, Hiroshi; Kunugita, Naoki; Takahashi, Kunihiko

2013-01-01

Since the Fukushima Daiichi nuclear power plant accident, concerns have arisen about the radiation safety of food raised at home and abroad. Therefore, many measures have been taken to address this. To evaluate the effectiveness of these measures, dose estimation due to food consumption has been attempted by various methods. In this paper, we show the results of dose estimation based on the monitoring data of radioactive materials in food published by the Ministry of Health, Labour and Welfare. The Radioactive Material Response Working Group in the Food Sanitation Subcommittee of the Pharmaceutical Affairs and Food Sanitation Council reported such dose estimation results on October 31, 2011 using monitoring data from immediately after the accident through September, 2011. Our results presented in this paper were the effective dose and thyroid equivalent dose integrated up to December 2012 from immediately after the accident. The estimated results of committed effective dose by age group derived from the radioiodine and radiocesium in food after the Fukushima Daiichi nuclear power plant accident showed the highest median value (0.19 mSv) in children 13-18 years of age. The highest 95% tile value, 0.33 mSv, was shown in the 1-6 years age range. These dose estimations from food can be useful for evaluation of radiation risk for individuals or populations and for radiation protection measures. It would also be helpful for the study of risk management of food in the future. (author)

A theoretical approach to the problem of dose-volume constraint estimation and their impact on the dose-volume histogram selection

International Nuclear Information System (INIS)

Schinkel, Colleen; Stavrev, Pavel; Stavreva, Nadia; Fallone, B. Gino

2006-01-01

This paper outlines a theoretical approach to the problem of estimating and choosing dose-volume constraints. Following this approach, a method of choosing dose-volume constraints based on biological criteria is proposed. This method is called ''reverse normal tissue complication probability (NTCP) mapping into dose-volume space'' and may be used as a general guidance to the problem of dose-volume constraint estimation. Dose-volume histograms (DVHs) are randomly simulated, and those resulting in clinically acceptable levels of complication, such as NTCP of 5±0.5%, are selected and averaged producing a mean DVH that is proven to result in the same level of NTCP. The points from the averaged DVH are proposed to serve as physical dose-volume constraints. The population-based critical volume and Lyman NTCP models with parameter sets taken from literature sources were used for the NTCP estimation. The impact of the prescribed value of the maximum dose to the organ, D max , on the averaged DVH and the dose-volume constraint points is investigated. Constraint points for 16 organs are calculated. The impact of the number of constraints to be fulfilled based on the likelihood that a DVH satisfying them will result in an acceptable NTCP is also investigated. It is theoretically proven that the radiation treatment optimization based on physical objective functions can sufficiently well restrict the dose to the organs at risk, resulting in sufficiently low NTCP values through the employment of several appropriate dose-volume constraints. At the same time, the pure physical approach to optimization is self-restrictive due to the preassignment of acceptable NTCP levels thus excluding possible better solutions to the problem

Dose estimation in CT exams of the abdomen based on values of DLP

International Nuclear Information System (INIS)

Kikuti, C.F.; Medeiros, R.B.; Salvadori, P.S.; Costa, D.M.C; D'lppolito, G.

2013-01-01

One of the challenges of multidetector computerized tomography is to minimize the risk of ionizing radiation using optimized protocols since higher doses are necessary to obtain high image quality. It was also noted that, due to the geometry in image acquisition using MDCT becomes necessary to estimate dose values consistent with the hypothesis clinically and with the specificities of the tomographic equipment. The aim of this study was to estimate the doses in abdomen exams from the data recorded on the MDCT console and dimensions obtained from DICOM images of patients undergoing different clinical protocols. Were collected, from the image DICOM of 101 exams, values of the dose length product (DLP) provided by Philips Health Care - Brilliance 64 equipment console, in order to relate them with the dose values obtained by means of thermoluminescent dosimeters ( TLD ) of CasSo 4 :Mn placed on the surface of a cylindrical simulator abdomen acrylic manufactured under the technical - operational conditions for a typical abdomen exam. From the data obtained, it was possible to find a factor of 1.16 ( 5 % ) indicating that the DLP values Brilliance 64 console underestimate the doses and this should be used with correction factor to estimate the total dose of the patient. (author)

Cardiac-Specific Conversion Factors to Estimate Radiation Effective Dose From Dose-Length Product in Computed Tomography.

Science.gov (United States)

Trattner, Sigal; Halliburton, Sandra; Thompson, Carla M; Xu, Yanping; Chelliah, Anjali; Jambawalikar, Sachin R; Peng, Boyu; Peters, M Robert; Jacobs, Jill E; Ghesani, Munir; Jang, James J; Al-Khalidi, Hussein; Einstein, Andrew J

2018-01-01

This study sought to determine updated conversion factors (k-factors) that would enable accurate estimation of radiation effective dose (ED) for coronary computed tomography angiography (CTA) and calcium scoring performed on 12 contemporary scanner models and current clinical cardiac protocols and to compare these methods to the standard chest k-factor of 0.014 mSv·mGy -1 cm -1 . Accurate estimation of ED from cardiac CT scans is essential to meaningfully compare the benefits and risks of different cardiac imaging strategies and optimize test and protocol selection. Presently, ED from cardiac CT is generally estimated by multiplying a scanner-reported parameter, the dose-length product, by a k-factor which was determined for noncardiac chest CT, using single-slice scanners and a superseded definition of ED. Metal-oxide-semiconductor field-effect transistor radiation detectors were positioned in organs of anthropomorphic phantoms, which were scanned using all cardiac protocols, 120 clinical protocols in total, on 12 CT scanners representing the spectrum of scanners from 5 manufacturers (GE, Hitachi, Philips, Siemens, Toshiba). Organ doses were determined for each protocol, and ED was calculated as defined in International Commission on Radiological Protection Publication 103. Effective doses and scanner-reported dose-length products were used to determine k-factors for each scanner model and protocol. k-Factors averaged 0.026 mSv·mGy -1 cm -1 (95% confidence interval: 0.0258 to 0.0266) and ranged between 0.020 and 0.035 mSv·mGy -1 cm -1 . The standard chest k-factor underestimates ED by an average of 46%, ranging from 30% to 60%, depending on scanner, mode, and tube potential. Factors were higher for prospective axial versus retrospective helical scan modes, calcium scoring versus coronary CTA, and higher (100 to 120 kV) versus lower (80 kV) tube potential and varied among scanner models (range of average k-factors: 0.0229 to 0.0277 mSv·mGy -1 cm -1 ). Cardiac k

Estimation Of Effective Dose In Ingestion Of Food Crops For 137Cs

International Nuclear Information System (INIS)

Angeleska, A.; Dimitrieska-Stojkovic, E.; Uzunov, R.; Hajrulai-Musliu, Z.; Stojanovska-Dimzoska, B.; Jankuloski, D.; Crceva-Nikolovska, R.

2015-01-01

The interaction of the ionizing radiation with the human body leads to various biological effects which afterwards can be manifested as clinical symptoms. The nature and the seriousness of the symptoms depend on the absorbed dose, as well as the dose rate, and many diseases which were supposed to be effectively managed if information for the radiation level of an environment was available. The knowledge of the concentration of radioactivity of our environment is of essential relevance in the assessment of the dose that is accumulated in the population, as well as for the formation of the basis for estimation of the level of radioactive contamination or contamination in the environment in future. Taking into consideration the relevance of the distribution and the transfer of radionuclides from the soil to the crops, this work was aimed to estimate the effective dose in ingestion of separate crops for 137Cs. The effective dose was determined by means of already known transfer factors from the soil to the plants and measured concentrations of activities of soil from specific locations in the surrounding of the city of Skopje. The agricultural crops used for analysis are the most commonly applied crops (vegetables, legumes, root crops) in Republic of Macedonia. The radiometric analysis of these samples was conducted by applying a spectrometer for gamma-rays with Germanium with high purity (HPGe). The estimated effective dose would apply for adults who ingested the mentioned crops which were produced at the mentioned locations, that is, in the region of Skopje. These data can be the basis for estimation of risk for radioactive contamination of the population, received by ingestion of produced food. (author).

The Sandia total-dose estimator: SANDOSE description and user guide

International Nuclear Information System (INIS)

Turner, C.D.

1995-02-01

The SANdia total-DOSe Estimator (SANDOSE) is used to estimate total radiation dose to a (BRL-CAT) solid model, SANDOSE uses the mass-sectoring technique to sample the model using ray-tracing techniques. The code is integrated directly into the BRL-CAD solid model editor and is operated using a simple graphical user interface. Several diagnostic tools are available to allow the user to analyze the results. Based on limited validation using several benchmark problems, results can be expected to fall between a 10% underestimate and a factor of 2 overestimate of the actual dose predicted by rigorous radiation transport techniques. However, other situations may be encountered where the results might fall outside of this range. The code is written in C and uses X-windows graphics. It presently runs on SUN SPARCstations, but in theory could be ported to any workstation with a C compiler and X-windows. SANDOSE is available via license by contacting either the Sandia National Laboratories Technology Transfer Center or the author

Estimation dose in organs of hyperthyroidism patients treated with I-131

International Nuclear Information System (INIS)

Farias de Lima, F.; Khoury, H.C.; Bertelli Neto, L.; Hazin, C.

1997-01-01

Full text: The absorbed dose in organs of hyperthyroidism patients, which received 370 MBq and 555 MBq of I-131 were estimated, using the MIRDOSE computational program and data of the ICRP-53 publication. The calculus were done considering an equal uptake to 45% and an effective half life of 5 days, these values are closed to the average values found in 17 studied patients. The thyroidal masses were previously determined by the physicians and varied between 40 g and 80 g The results showed that the dose in the thyroid, for an activity of 370 MBq, varied between 99 Gy and 49,5 Gy for the masses of 40 g and 80 g respectively. In the case of the administration of 555 MBq the patients had thyroidal masses between 60 g and 80 g and the doses varied between 99 Gy and 74,2 Gy, respectively. These values showed that the absorbed doses in thyroid are within limits expected for the hyperthyroidism therapy, which are of 506 Gy to 100 Gy. The 100 Gy dose would be exceeded, if the patients with thyroidal mass of 40 g had received a therapeutic dose of 555 MBq. The estimated media doses in others organs were relatively low, with inferior values of 0,1 Gy in kidneys, bone marrow and ovaries and of 0,19 Gy in stomach

Patient absorbed radiation doses estimation related to irradiation anatomy; Estimativa de dose absorvida pelo paciente relacionada a anatomia irradiada

Energy Technology Data Exchange (ETDEWEB)

Soares, Flavio Augusto Penna; Soares, Amanda Anastacio; Kahl, Gabrielly Gomes, E-mail: prof.flavio@gmail.com, E-mail: amanda-a-soares@hotmail.com, E-mail: gabriellygkahl@gmail.com [Instituto Federal de Eduacao, Ciencia e Tecnologia de Santa Catarina (IFSC), Florianopolis, SC (Brazil)

2014-07-01

Developed a direct equation to estimate the absorbed dose to the patient in x-ray examinations, using electric, geometric parameters and filtering combined with data from irradiated anatomy. To determine the absorbed dose for each examination, the entrance skin dose (ESD) is adjusted to the thickness of the patient's specific anatomy. ESD is calculated from the estimated KERMA greatness in the air. Beer-Lambert equations derived from power data mass absorption coefficients obtained from the NIST / USA, were developed for each tissue: bone, muscle, fat and skin. Skin thickness was set at 2 mm and the bone was estimated in the central ray of the site, in the anteroposterior view. Because they are similar in density and attenuation coefficients, muscle and fat are treated as a single tissue. For evaluation of the full equations, we chose three different anatomies: chest, hand and thigh. Although complex in its shape, the equations simplify direct determination of absorbed dose from the characteristics of the equipment and patient. The input data is inserted at a single time and total absorbed dose (mGy) is calculated instantly. The average error, when compared with available data, is less than 5% in any combination of device data and exams. In calculating the dose for an exam and patient, the operator can choose the variables that will deposit less radiation to the patient through the prior analysis of each combination of variables, using the ALARA principle in routine diagnostic radiology sector.

Impact of dose-distribution uncertainties on rectal ntcp modeling I: Uncertainty estimates

International Nuclear Information System (INIS)

Fenwick, John D.; Nahum, Alan E.

2001-01-01

A trial of nonescalated conformal versus conventional radiotherapy treatment of prostate cancer has been carried out at the Royal Marsden NHS Trust (RMH) and Institute of Cancer Research (ICR), demonstrating a significant reduction in the rate of rectal bleeding reported for patients treated using the conformal technique. The relationship between planned rectal dose-distributions and incidences of bleeding has been analyzed, showing that the rate of bleeding falls significantly as the extent of the rectal wall receiving a planned dose-level of more than 57 Gy is reduced. Dose-distributions delivered to the rectal wall over the course of radiotherapy treatment inevitably differ from planned distributions, due to sources of uncertainty such as patient setup error, rectal wall movement and variation in the absolute rectal wall surface area. In this paper estimates of the differences between planned and treated rectal dose-distribution parameters are obtained for the RMH/ICR nonescalated conformal technique, working from a distribution of setup errors observed during the RMH/ICR trial, movement data supplied by Lebesque and colleagues derived from repeat CT scans, and estimates of rectal circumference variations extracted from the literature. Setup errors and wall movement are found to cause only limited systematic differences between mean treated and planned rectal dose-distribution parameter values, but introduce considerable uncertainties into the treated values of some dose-distribution parameters: setup errors lead to 22% and 9% relative uncertainties in the highly dosed fraction of the rectal wall and the wall average dose, respectively, with wall movement leading to 21% and 9% relative uncertainties. Estimates obtained from the literature of the uncertainty in the absolute surface area of the distensible rectal wall are of the order of 13%-18%. In a subsequent paper the impact of these uncertainties on analyses of the relationship between incidences of bleeding

NIRS external dose estimation system for Fukushima residents after the Fukushima Dai-ichi NPP accident

Science.gov (United States)

Akahane, Keiichi; Yonai, Shunsuke; Fukuda, Shigekazu; Miyahara, Nobuyuki; Yasuda, Hiroshi; Iwaoka, Kazuki; Matsumoto, Masaki; Fukumura, Akifumi; Akashi, Makoto

2013-04-01

The great east Japan earthquake and subsequent tsunamis caused Fukushima Dai-ichi Nuclear Power Plant (NPP) accident. National Institute of Radiological Sciences (NIRS) developed the external dose estimation system for Fukushima residents. The system is being used in the Fukushima health management survey. The doses can be obtained by superimposing the behavior data of the residents on the dose rate maps. For grasping the doses, 18 evacuation patterns of the residents were assumed by considering the actual evacuation information before using the survey data. The doses of the residents from the deliberate evacuation area were relatively higher than those from the area within 20 km radius. The estimated doses varied from around 1 to 6 mSv for the residents evacuated from the representative places in the deliberate evacuation area. The maximum dose in 18 evacuation patterns was estimated to be 19 mSv.

I-125 seed dose estimates in heterogeneous phantom

International Nuclear Information System (INIS)

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

2015-01-01

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

I-125 seed dose estimates in heterogeneous phantom

Energy Technology Data Exchange (ETDEWEB)

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

2015-07-01

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

Estimation of population doses from stomach mass screening, 1975

Energy Technology Data Exchange (ETDEWEB)

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

1977-06-01

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

Improvements on a patient-specific dose estimation system in nuclear medicine examination

International Nuclear Information System (INIS)

Chuang, K. S.; Lu, J. C.; Lin, H. H.; Dong, S. L.; Yang, H. J.; Shih, C. T.; Lin, C. H.; Yao, W. J.; Ni, Y. C.; Jan, M. L.; Chang, S. J.

2014-01-01

The purpose of this paper is to develop a patient-specific dose estimation system in nuclear medicine examination. A dose deposition routine to store the deposited energy of the photons during their flights was embedded in the widely used SimSET Monte Carlo code and a user-friendly interface for reading PET and CT images was developed. Dose calculated on ORNL phantom was used to validate the accuracy of this system. The ratios of S value for 99m Tc, 18 F and 131 I computed by this system to those obtained with OLINDA for various organs were ranged from 0.93 to 1.18, which were comparable to that obtained from MCNPX2.6 code (0.88-1.22). Our system developed provides opportunity for tumor dose estimation which cannot be known from the MIRD. The radiation dose can provide useful information in the amount of radioisotopes to be administered in radioimmunotherapy. (authors)

Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

International Nuclear Information System (INIS)

Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

2014-01-01

In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens

Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

Science.gov (United States)

Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

2014-11-01

In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

Energy Technology Data Exchange (ETDEWEB)

Alva-Sánchez, Héctor, E-mail: halva@ciencias.unam.mx [Unidad de Imagen Molecular PET/CT, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F. (Mexico); Reynoso-Mejía, Alberto [Unidad de Imagen Molecular PET/CT, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F., Mexico and Departamento de Neuroimagen, Instituto Nacional de (Mexico); Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús [Departamento de Neuroimagen, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F. (Mexico)

2014-11-07

In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

Foetal and adult human CYP3A isoforms in the bioactivation of organophosphorothionate insecticides.

Science.gov (United States)

Buratti, Franca M; Leoni, Claudia; Testai, Emanuela

2006-12-15

In humans organophosphorothionate pesticides (OPT) prenatal exposure has been demonstrated. Since OPT-induced neurodevelopmental effects may be due to in situ bioactivation by foetal enzymes, the catalytic activity of the foetal CYP3A7 toward chlorpyrifos (CPF), parathion (PAR), malathion (MAL) and fenthion (FEN) has been assessed by using recombinant enzymes. A comparison with the adult isoforms CYP3A4 and CYP3A5 has been also carried out. CYP3A7 was able to produce significant levels of oxon or sulfoxide from the four OPTs in the range of tested concentrations (0.05-200 microM). When the efficiencies of CYP3A isoforms were compared, the ranking, expressed as CLi values, were: CPF=3A4>3A5>3A7; PAR=3A4>3A7>3A5; MAL=3A4>3A7>3A5; FEN (sulfoxide formation)=3A4>3A5>3A7. The CYP3A5 efficiency appeared to be more dependent on the single insecticide than its related isozyme CYP3A4. Our results indicate that the levels of toxic metabolite formed in situ by CYP3A7 from CPF, MAL and PAR but not from FEN have the chance to inhibit acetylcholinesterase, following prenatal exposure to OPTs. However, due to the smaller weight of foetal liver, the contribution to total OPT biotransformation is relatively low. On the other hand, our results clearly indicate that at low CPF concentrations, the formation of the non-toxic metabolites is highly favoured in the foetus.

Estimation of dose distribution in occupationally exposed individuals to FDG-18F

International Nuclear Information System (INIS)

Lacerda, Isabelle V. Batista de; Cabral, Manuela O. Monteiro; Vieira, Jose Wilson

2014-01-01

The use of unsealed radiation sources in nuclear medicine can lead to important incorporation of radionuclides, especially for occupationally exposed individuals (OEIs) during production and handling of radiopharmaceuticals. In this study, computer simulation was proposed as an alternative methodology for evaluation of the absorbed dose distribution and for the effective dose value in OEIs. For this purpose, the Exposure Computational Model (ECM) which is named as FSUP (Female Adult Mesh - supine) were used. This ECM is composed of: voxel phantom FASH (Female Adult MeSH) in the supine position, the MC code EGSnrc and an algorithm simulator of general internal source. This algorithm was modified to adapt to specific needs of the positron emission from FDG- 18 F. The obtained results are presented as absorbed dose/accumulated activity. To obtain the absorbed dose distribution it was necessary to use accumulative activity data from the in vivo bioassay. The absorbed dose distribution and the value of estimated effective dose in this study did not exceed the limits for occupational exposure. Therefore, the creation of a database with the distribution of accumulated activity is suggested in order to estimate the absorbed dose in radiosensitive organs and the effective dose for OEI in similar environment. (author)

Fetal dose from radiotherapy photon beams: Physical basis, techniques to estimate radiation dose outside of the treatment field, biological effects and professional considerations

International Nuclear Information System (INIS)

Stovell, Marilyn; Blackwell, C. Robert

1997-01-01

Purpose/Objective: The presentation will review: 1. The physical basis of radiation dose outside of the treatment field. 2. Techniques to estimate and reduce fetal dose. 3. Clinical examples of fetal dose estimation and reduction. 4. Biological effects of fetal irradiation. 5. Professional considerations. Approximately 4000 women per year in the United States require radiotherapy during pregnancy. This report presents data and techniques that allow the medical physicist to estimate the radiation dose the fetus will receive and to reduce this dose with appropriate shielding. Out-of-beam data are presented for a variety of photon beams, including cobalt-60 gamma rays and x rays from 4 to 18 MV. Designs for simple and inexpensive to more complex and expensive types of shielding equipment are described. Clinical examples show that proper shielding can reduce the radiation dose to the fetus by 50%. In addition, a review of the biological aspects of irradiation enables estimates of the risks of lethality, growth retardation, mental retardation, malformation, sterility, cancer induction, and genetic defects to the fetus. A summary of professional considerations/recommendations is also provided as a guide for the radiation oncologist and medical physicist

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

International Nuclear Information System (INIS)

Al Achkar, W.

2002-01-01

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

Effects of the loss of correlation structure on Phase 1 dose estimates

International Nuclear Information System (INIS)

Simpson, J.C.

1991-11-01

In Phase I of the Hanford Environmental Dose Reconstruction Project, a step-by-step (modular) calculational structure was used. This structure was intended (1) to simplify the computational process, (2) to allow storage of intermediate calculations for later analyses, and (3) to guide the collection of data by presenting understandable structures for its use. The implementation of this modular structure resulted in the loss of correlation among inputs and outputs of the code, resulting in less accurate dose estimates than anticipated. The study documented in this report investigated two types of correlations in the Phase I model: temporal and pathway. Temporal correlations occur in the simulation when, in the calculation, data estimated for a previous time are used in a subsequent calculation. If the various portions of the calculation do not use the same realization of the earlier estimate, they are no longer correlated with respect to time. Similarly, spatial correlations occur in a simulation when, in the calculation, data estimated for a particular location are used in estimates for other locations. If the various calculations do not use the same value for the original location, they are no longer correlated with respect to location. The loss of the correlation structure in the Phase I code resulted in dose estimates that are biased. It is recommended that the air pathway dose model be restructured and the intermediate histograms eliminated. While the restructured code may still contain distinct modules, all input parameters to each module and all out put from each module should be retained in a database such that subsequent modules can access all the information necessary to retain the correlation structure

Estimation of four-dimensional dose distribution using electronic portal imaging device in radiation therapy

International Nuclear Information System (INIS)

Mizoguchi, Asumi; Arimura, Hidetaka; Shioyama, Yoshiyuki

2013-01-01

We are developing a method to evaluate four-dimensional radiation dose distribution in a patient body based upon the animated image of EPID (electronic portal imaging device) which is an image of beam-direction at the irradiation. In the first place, we have obtained the image of the dose which is emitted from patient body at therapy planning using therapy planning CT image and dose evaluation algorism. In the second place, we have estimated the emission dose image at the irradiation using EPID animated image which is obtained at the irradiation. In the third place, we have got an affine transformation matrix including respiratory movement in the body by performing linear registration on the emission dose image at therapy planning to get the one at the irradiation. In the fourth place, we have applied the affine transformation matrix on the therapy planning CT image and estimated the CT image 'at irradiation'. Finally we have evaluated four-dimensional dose distribution by calculating dose distribution in the CT image 'at irradiation' which has been estimated for each frame of the EPID animated-image. This scheme may be useful for evaluating therapy results and risk management. (author)

Estimation of effective dose during hysterosalpingography procedures

International Nuclear Information System (INIS)

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

2014-08-01

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

Studies on the reference Korean and estimation of radiation exposure dose

International Nuclear Information System (INIS)

Kim, Y.J.; Lee, K.S.; Chun, K.J.; Kim, J.B.; Chung, G.H.; Kim, S.R.

1982-01-01

For the purpose of establishment of Reference Korean and estimation of internal and external exposure doses in the Reference Korean, we have surveyed reference values for Koreans such as physical standards including height, weight, and body surface area, food consumption rate of daily intake of radioactive substances and exposure dose from natural radiation. (Author)

Estimating patient dose from CT exams that use automatic exposure control: Development and validation of methods to accurately estimate tube current values.

Science.gov (United States)

McMillan, Kyle; Bostani, Maryam; Cagnon, Christopher H; Yu, Lifeng; Leng, Shuai; McCollough, Cynthia H; McNitt-Gray, Michael F

2017-08-01

The vast majority of body CT exams are performed with automatic exposure control (AEC), which adapts the mean tube current to the patient size and modulates the tube current either angularly, longitudinally or both. However, most radiation dose estimation tools are based on fixed tube current scans. Accurate estimates of patient dose from AEC scans require knowledge of the tube current values, which is usually unavailable. The purpose of this work was to develop and validate methods to accurately estimate the tube current values prescribed by one manufacturer's AEC system to enable accurate estimates of patient dose. Methods were developed that took into account available patient attenuation information, user selected image quality reference parameters and x-ray system limits to estimate tube current values for patient scans. Methods consistent with AAPM Report 220 were developed that used patient attenuation data that were: (a) supplied by the manufacturer in the CT localizer radiograph and (b) based on a simulated CT localizer radiograph derived from image data. For comparison, actual tube current values were extracted from the projection data of each patient. Validation of each approach was based on data collected from 40 pediatric and adult patients who received clinically indicated chest (n = 20) and abdomen/pelvis (n = 20) scans on a 64 slice multidetector row CT (Sensation 64, Siemens Healthcare, Forchheim, Germany). For each patient dataset, the following were collected with Institutional Review Board (IRB) approval: (a) projection data containing actual tube current values at each projection view, (b) CT localizer radiograph (topogram) and (c) reconstructed image data. Tube current values were estimated based on the actual topogram (actual-topo) as well as the simulated topogram based on image data (sim-topo). Each of these was compared to the actual tube current values from the patient scan. In addition, to assess the accuracy of each method in estimating

Estimation of 1945 to 1957 food consumption. Hanford Environmental Dose Reconstruction Project: Draft

Energy Technology Data Exchange (ETDEWEB)

Anderson, D.M.; Bates, D.J.; Marsh, T.L.

1993-03-01

This report details the methods used and the results of the study on the estimated historic levels of food consumption by individuals in the Hanford Environmental Dose Reconstruction (HEDR) study area from 1945--1957. This period includes the time of highest releases from Hanford and is the period for which data are being collected in the Hanford Thyroid Disease Study. These estimates provide the food-consumption inputs for the HEDR database of individual diets. This database will be an input file in the Hanford Environmental Dose Reconstruction Integrated Code (HEDRIC) computer model that will be used to calculate the radiation dose. The report focuses on fresh milk, eggs, lettuce, and spinach. These foods were chosen because they have been found to be significant contributors to radiation dose based on the Technical Steering Panel dose decision level.

Effective dose to staff from interventional procedures: Estimations from single and double dosimetry

International Nuclear Information System (INIS)

Kuipers, G.; Velders, X. L.

2009-01-01

The exposure of 11 physicians performing interventional procedures was measured by means of two personal dosemeters. One personal dosemeter was worn outside the lead apron and an additional under the lead apron. The study was set up in order to determine the added value of a dosemeter worn under the lead apron. With the doses measured, the effective doses of the physicians were estimated using an algorithm for single dosimetry and two algorithms for double dosimetry. The effective doses calculated with the single dosimetry algorithm ranged from 0.11 to 0.85 mSv in 4 weeks. With the double dosimetry algorithms, the effective doses ranged from 0.02 mSv to 0.47 mSv. The statistical analysis revealed no significant differences in the accuracy of the effective doses calculated with single or double dosimetry algorithms. It was concluded that the effective dose cannot be considered a more accurate estimate when two dosemeters are used instead of one. (authors)

Radiochemical separation and effective dose estimation due to ingestion of 90Sr

International Nuclear Information System (INIS)

Ilic, Z.; Vidic, A.; Deljkic, D.; Sirko, D.; Zovko, E.; Samek, D.

2009-01-01

Since 2007. Institute for Public Health of Federation of Bosnia and Herzegovina-Radiation Protection Centre, within the framework of monitoring of radioactivity of environment carried out measurement of specific activity of 90 Sr content in selected food and water samples. The paper described the methods of measurement and radiochemical separation. Presented results, as average values of specific activity of 90 Sr, were used for estimation of effective dose due to ingestion of 90 Sr for 2007. and 2008. Estimated effective dose for 2007. due to ingestion of 90 Sr for adults was 1,36 μSv and 2,03 μSv for children (10 year old), and for 2008. 0,67 μSv (adults) and 1,01 μSv (children 10 year old). Estimated effective doses for 2007. and 2008. are varied because of different average specific activity radionuclide 90 Sr in selected samples of food, their number, species and origin. (author) [sr

Foetal proglucagon processing in relation to adult appetite control

DEFF Research Database (Denmark)

Jensen, P B; Larsen, P J; Karlsen, C

2011-01-01

with a foetal processing pattern of proglucagon to both glucagon and GLP-1 (7-36amide), and is due to taste aversion. The sudden onset is characterized by a dramatic increase in circulating levels of biologically active GLP-1 (7-36amide), suggesting eventual saturation of proteolytic inactivation of its N-terminus....... neuropeptide Y (NPY) mRNA levels in the nucleus arcuatus. We now show that circulating levels of bioactive glucagon-like peptide-1 (GLP-1) (7-36amide) start to increase above control levels exactly at the time of onset of anorexia. At this time-point, bioactive glucagon as well as total glucagon precursors...

Internal dose estimates

International Nuclear Information System (INIS)

Wrenn, M.E.

1977-01-01

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

A comparison study of size-specific dose estimate calculation methods

Energy Technology Data Exchange (ETDEWEB)

Parikh, Roshni A. [Rainbow Babies and Children' s Hospital, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Department of Radiology, Cleveland, OH (United States); University of Michigan Health System, Department of Radiology, Ann Arbor, MI (United States); Wien, Michael A.; Jordan, David W.; Ciancibello, Leslie; Berlin, Sheila C. [Rainbow Babies and Children' s Hospital, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Department of Radiology, Cleveland, OH (United States); Novak, Ronald D. [Rainbow Babies and Children' s Hospital, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Department of Radiology, Cleveland, OH (United States); Rebecca D. Considine Research Institute, Children' s Hospital Medical Center of Akron, Center for Mitochondrial Medicine Research, Akron, OH (United States); Klahr, Paul [CT Clinical Science, Philips Healthcare, Highland Heights, OH (United States); Soriano, Stephanie [Rainbow Babies and Children' s Hospital, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Department of Radiology, Cleveland, OH (United States); University of Washington, Department of Radiology, Seattle, WA (United States)

2018-01-15

The size-specific dose estimate (SSDE) has emerged as an improved metric for use by medical physicists and radiologists for estimating individual patient dose. Several methods of calculating SSDE have been described, ranging from patient thickness or attenuation-based (automated and manual) measurements to weight-based techniques. To compare the accuracy of thickness vs. weight measurement of body size to allow for the calculation of the size-specific dose estimate (SSDE) in pediatric body CT. We retrospectively identified 109 pediatric body CT examinations for SSDE calculation. We examined two automated methods measuring a series of level-specific diameters of the patient's body: method A used the effective diameter and method B used the water-equivalent diameter. Two manual methods measured patient diameter at two predetermined levels: the superior endplate of L2, where body width is typically most thin, and the superior femoral head or iliac crest (for scans that did not include the pelvis), where body width is typically most thick; method C averaged lateral measurements at these two levels from the CT projection scan, and method D averaged lateral and anteroposterior measurements at the same two levels from the axial CT images. Finally, we used body weight to characterize patient size, method E, and compared this with the various other measurement methods. Methods were compared across the entire population as well as by subgroup based on body width. Concordance correlation (ρ{sub c}) between each of the SSDE calculation methods (methods A-E) was greater than 0.92 across the entire population, although the range was wider when analyzed by subgroup (0.42-0.99). When we compared each SSDE measurement method with CTDI{sub vol,} there was poor correlation, ρ{sub c}<0.77, with percentage differences between 20.8% and 51.0%. Automated computer algorithms are accurate and efficient in the calculation of SSDE. Manual methods based on patient thickness provide

No histologic evidence of foetal cardiotoxicity following exposure to maternal hydroxychloroquine.

Science.gov (United States)

Friedman, Deborah; Lovig, Leif; Halushka, Marc; Clancy, Robert M; Izmirly, Peter M; Buyon, Jill P

2017-01-01

It is currently recommended that hydroxychloroquine (HCQ) be maintained during pregnancy in patients with systemic lupus erythematosus. Recent data suggest that this Toll-like receptor inhibitor may also reduce the recurrence rate of anti-SSA/Ro associated congenital heart block (CHB). This case report describes a unique situation in which a CHB-afflicted, HCQ-exposed pregnancy was electively terminated. The heart did not reveal any characteristic features of cardiotoxicity, providing further evidence supporting the safety of foetal exposure to HCQ.

Dose estimate for personal music players including earphone sensitivity and characteristic

DEFF Research Database (Denmark)

Hammershøi, Dorte; Ordoñez Pizarro, Rodrigo Eduardo; Christensen, Anders Tornvig

2016-01-01

Personal music players can expose their listeners to high sound pressure levels over prolonged periods of time. The risk associated with prolonged listening is not readily available to the listener, and efforts are made to standardize dose estimates that may be displayed for the user. In the pres......Personal music players can expose their listeners to high sound pressure levels over prolonged periods of time. The risk associated with prolonged listening is not readily available to the listener, and efforts are made to standardize dose estimates that may be displayed for the user...... earphone measurements published in the past. The work is on-going....

Testicular shield for para-aortic radiotherapy and estimation of gonad doses.

Science.gov (United States)

Ravichandran, R; Binukumar, J P; Kannadhasan, S; Shariff, M H; Ghamrawy, Kamal El

2008-10-01

For radiotherapy of para-aortic and abdominal regions in male patients, gonads are to be protected to receive less than 2% of the prescribed dose. A testicular shield was fabricated for abdominal radiotherapy with 15 MV X-rays ((Clinac 2300 CD, Varian AG) with low melting point alloy (Cerroband). The dimensions of the testicular shield were 6.5 cm diameter and 3.5 cm depth with 1.5 cm wall thickness. During treatment, this shield was held in position by a rectangular sponge and Styrofoam support. Phantom measurement was carried out with a humanoid phantom and a 0.6 cc ion chamber. The mean energy of the scattered photon was calculated for single scattering at selected distances from the beam edge and with different field dimensions. One patient received radiotherapy with an inverted Y field and gonad doses were estimated using calibrated thermo-luminescent detector (TLD) chips. Measured doses with the ion chamber were 7.1 and 3.5% of the mid-plane doses without a shield at 3 and 7.5 cm off-field respectively. These values decreased to 4.6 and 1.7% with the bottom shield alone, and to 1.7 and 0.8% with both bottom and top shields covering the ion chamber. The measured doses at the gonads during the patient's treatment were 0.5-0.92% for the AP field (0.74 +/- 0.17%, n = 5) and 0.5-1.2% for the PA field (0.88 +/- 0.24%, n = 5). The dose received by the testis for the full course of treatment was 32 cGy (0.8%) for a total mid-plane dose of 40 Gy. The first-scatter energy estimated at the gonads is around 1.14 MeV for a primary beam of 15 MV for a long axis dimension of 37 cm of primary field. During the patient's treatment, the estimated absorbed doses at the gonads were comparable with reported values in similar treatments. The testicular shield reported in this study is of light weight and could be used conveniently in treatments of abdominal fields.

Testicular shield for para-aortic radiotherapy and estimation of gonad doses

Directory of Open Access Journals (Sweden)

Ravichandran R

2008-01-01

Full Text Available For radiotherapy of para-aortic and abdominal regions in male patients, gonads are to be protected to receive less than 2% of the prescribed dose. A testicular shield was fabricated for abdominal radiotherapy with 15 MV X-rays ((Clinac 2300 CD, Varian AG with low melting point alloy (Cerroband. The dimensions of the testicular shield were 6.5 cm diameter and 3.5 cm depth with 1.5 cm wall thickness. During treatment, this shield was held in position by a rectangular sponge and Styrofoam support. Phantom measurement was carried out with a humanoid phantom and a 0.6 cc ion chamber. The mean energy of the scattered photon was calculated for single scattering at selected distances from the beam edge and with different field dimensions. One patient received radiotherapy with an inverted Y field and gonad doses were estimated using calibrated thermo-luminescent detector (TLD chips. Measured doses with the ion chamber were 7.1 and 3.5% of the mid-plane doses without a shield at 3 and 7.5 cm off-field respectively. These values decreased to 4.6 and 1.7% with the bottom shield alone, and to 1.7 and 0.8% with both bottom and top shields covering the ion chamber. The measured doses at the gonads during the patient′s treatment were 0.5-0.92% for the AP field (0.74 ± 0.17%, n = 5 and 0.5-1.2% for the PA field (0.88 ± 0.24%, n = 5. The dose received by the testis for the full course of treatment was 32 cGy (0.8% for a total mid-plane dose of 40 Gy. The first-scatter energy estimated at the gonads is around 1.14 MeV for a primary beam of 15 MV for a long axis dimension of 37 cm of primary field. During the patient′s treatment, the estimated absorbed doses at the gonads were comparable with reported values in similar treatments. The testicular shield reported in this study is of light weight and could be used conveniently in treatments of abdominal fields.

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

International Nuclear Information System (INIS)

Al-Achkar, W.

2001-09-01

In order to draw a dose-effect curve, experimentally gamma ray induced chromosomal aberrations in human peripheral lymphocytes from eight healthy people were studied. Samples from 4 males and 4 females were irradiated in tubes with 0.15, 0.25, 0.5, 1, 1.5, 2, 2.5 gray of gamma ray (Co 60 at dose rate 0.3 Gy/min). Irradiated and control samples were incubated in 37 centigrade for 48 hours cell cultures. Cell cultures then were stopped and metaphases spread, Giemsa stained to score the induced chromosomal aberrations. Chromosomal aberrations from 67888 metaphases were scored. Curves from the total number of dicentrics, dicentrics + rings and total numbers of breaks in cell for each individual or for all people were drawn. An increase of all chromosomal aberrations types with the elevation of the doses was observed. The yield of chromosome aberrations is related to the dose used. These curves give a quick useful estimation of the accidentally radiation exposure. (author)

Loss-of-function mutations in SCN4A> cause severe foetal hypokinesia or 'classical' congenital myopathy

DEFF Research Database (Denmark)

Zaharieva, Irina T; Thor, Michael G; Oates, Emily C

2016-01-01

Congenital myopathies are a clinically and genetically heterogeneous group of muscle disorders characterized by congenital or early-onset hypotonia and muscle weakness, and specific pathological features on muscle biopsy. The phenotype ranges from foetal akinesia resulting in in utero or neonatal...

Estimation of exposed dose, 1

International Nuclear Information System (INIS)

Okajima, Shunzo

1976-01-01

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

Comparison of internal dose estimates obtained using organ-level, voxel S value, and Monte Carlo techniques

Energy Technology Data Exchange (ETDEWEB)

Grimes, Joshua, E-mail: grimes.joshua@mayo.edu [Department of Physics and Astronomy, University of British Columbia, Vancouver V5Z 1L8 (Canada); Celler, Anna [Department of Radiology, University of British Columbia, Vancouver V5Z 1L8 (Canada)

2014-09-15

Purpose: The authors’ objective was to compare internal dose estimates obtained using the Organ Level Dose Assessment with Exponential Modeling (OLINDA/EXM) software, the voxel S value technique, and Monte Carlo simulation. Monte Carlo dose estimates were used as the reference standard to assess the impact of patient-specific anatomy on the final dose estimate. Methods: Six patients injected with{sup 99m}Tc-hydrazinonicotinamide-Tyr{sup 3}-octreotide were included in this study. A hybrid planar/SPECT imaging protocol was used to estimate {sup 99m}Tc time-integrated activity coefficients (TIACs) for kidneys, liver, spleen, and tumors. Additionally, TIACs were predicted for {sup 131}I, {sup 177}Lu, and {sup 90}Y assuming the same biological half-lives as the {sup 99m}Tc labeled tracer. The TIACs were used as input for OLINDA/EXM for organ-level dose calculation and voxel level dosimetry was performed using the voxel S value method and Monte Carlo simulation. Dose estimates for {sup 99m}Tc, {sup 131}I, {sup 177}Lu, and {sup 90}Y distributions were evaluated by comparing (i) organ-level S values corresponding to each method, (ii) total tumor and organ doses, (iii) differences in right and left kidney doses, and (iv) voxelized dose distributions calculated by Monte Carlo and the voxel S value technique. Results: The S values for all investigated radionuclides used by OLINDA/EXM and the corresponding patient-specific S values calculated by Monte Carlo agreed within 2.3% on average for self-irradiation, and differed by as much as 105% for cross-organ irradiation. Total organ doses calculated by OLINDA/EXM and the voxel S value technique agreed with Monte Carlo results within approximately ±7%. Differences between right and left kidney doses determined by Monte Carlo were as high as 73%. Comparison of the Monte Carlo and voxel S value dose distributions showed that each method produced similar dose volume histograms with a minimum dose covering 90% of the volume (D90

Are foetal ultrasonographic and maternal blood progesterone measurements near parturition reliable predictors of the time of birth in the domestic cat?

Science.gov (United States)

Keiser, R; Reichler, I M; Balogh, O

2017-06-01

In cats, accuracy of parturition day prediction by ultrasonographic measurement of foetal structures is decreasing towards the end of gestation. Foetal measurements during the last days of pregnancy are scarce. We determined foetal biparietal, abdominal and eye diameter (BPD, AD and ED, respectively) by ultrasonography as well as maternal blood progesterone (P4) within five days of delivery to predict parturition date and calculate accuracy of prediction. Foetal BPD at birth was compared with newborn kitten head diameter (HD). Kitten HD, crown-rump length (CRL) and body weight were compared by breed and gender. Ultrasonography measurements were carried out on the day of parturition in 14 queens, and on days 62-63 after the first mating and repeated 24-72 hr later in ten other cats. Accuracy of parturition day prediction using BPD and AD was determined based on the equations of Beccaglia et al. (2008) Veterinary Research Communications, 32(Suppl 1), S99 and Garcia Mitacek et al. (2015) Theriogenology, 84, 1131. Progesterone was measured at the time of presentation and repeated 24-72 hr later if parturition did not occur. Data were analysed with linear regression, t test, Mann-Whitney U test, one-way anova and Kruskal-Wallis test. There was a moderate relationship between BPD, days before birth (DBB) and litter size. AD and DBB had a low agreement, and ED was not associated with DBB. BPD at birth was significantly related to HD. The accuracy of parturition day prediction using BPD and AD was 27-53% and 17-35%, respectively. Kitten HD was associated with body weight, and both were inversely related to litter size. Newborn biometric measurements differed by breed but not by gender. Progesterone decreased towards parturition and reached 3.18 ± 1.68 ng/ml on the day of delivery. In conclusion, close to birth, the combination of foetal ultrasonography and maternal blood P4 rather than each as a sole predictor of parturition is recommended. © 2017 Blackwell Verlag

Estimation and comparison of effective dose (E) in standard chest CT by organ dose measurements and dose-length-product methods and assessment of the influence of CT tube potential (energy dependency) on effective dose in a dual-source CT

International Nuclear Information System (INIS)

Paul, Jijo; Banckwitz, Rosemarie; Krauss, Bernhard; Vogl, Thomas J.; Maentele, Werner; Bauer, Ralf W.

2012-01-01

Highlights: ► The dual-energy protocol delivers the lowest effective dose of the investigated protocols for standard chest CT examinations, thus enabling functional imaging (like dual-energy perfusion) and can produce weighted images without dose penalty. ► The high-pitch protocol goes along with a 16% increase in dose compared to the standard 120 kV protocol and thus should preferably be used in pediatric, acute care settings (e.g. pulmonary embolism, aortic dissection and the like) or restless patients. ► The difference in effective dose estimates between ICRP 60 and 103 is minimal. ► Tube potential definitely has an effect on estimates of effective dose. - Abstract: Purpose: To determine effective dose (E) during standard chest CT using an organ dose-based and a dose-length-product-based (DLP) approach for four different scan protocols including high-pitch and dual-energy in a dual-source CT scanner of the second generation. Materials and methods: Organ doses were measured with thermo luminescence dosimeters (TLD) in an anthropomorphic male adult phantom. Further, DLP-based dose estimates were performed by using the standard 0.014 mSv/mGycm conversion coefficient k. Examinations were performed on a dual-source CT system (Somatom Definition Flash, Siemens). Four scan protocols were investigated: (1) single-source 120 kV, (2) single-source 100 kV, (3) high-pitch 120 kV, and (4) dual-energy with 100/Sn140 kV with equivalent CTDIvol and no automated tube current modulation. E was then determined following recommendations of ICRP publication 103 and 60 and specific k values were derived. Results: DLP-based estimates differed by 4.5–16.56% and 5.2–15.8% relatively to ICRP 60 and 103, respectively. The derived k factors calculated from TLD measurements were 0.0148, 0.015, 0.0166, and 0.0148 for protocol 1, 2, 3 and 4, respectively. Effective dose estimations by ICRP 103 and 60 for single-energy and dual-energy protocols show a difference of less than 0.04 m

Rapid analysis of key radionuclides in urine and estimation of internal dose for nuclear accident emergency

International Nuclear Information System (INIS)

Zhao Shuquan; Hu Heping; Wu Mingyu; Zhu Guoying; Huang Shibin; Liu Shiming

2005-01-01

Objective: To estimate the internal doses of a Chinese visiting scholar in the Chernobyl accident. Methods: The contents of 134 Cs and 137 Cs in urine were measured using a Ge(Li) γ-spectrometer. Their internal doses were estimated according to ICRP reports. Dose review of 131I was performed referring to UNSCEAR 2000 report. Results: The effective dose equivalent from 134 Cs, 137 Cs and 131 I were 66 μSv, 88 μSv and 1728 μSv respectively. Their summation was 1.9 mSv. Conclusion: The internal dose from 131 I was 10 times higher than that from 134 Cs and 137 Cs. So, the earlier estimation of internal doses for 131 I is significant in evaluation on radiation injuries of a nuclear reactor accident. (authors)

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

International Nuclear Information System (INIS)

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

1983-01-01

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

Identification and characterization of insulin receptors on foetal-mouse brain-cortical cells.

OpenAIRE

Van Schravendijk, C F; Hooghe-Peters, E L; De Meyts, P; Pipeleers, D G

1984-01-01

The occurrence of insulin receptors was investigated in freshly dissociated brain-cortical cells from mouse embryos. By analogy with classical insulin-binding cell types, binding of 125I-insulin to foetal brain-cortical cells was time- and pH-dependent, only partially reversible, and competed for by unlabelled insulin and closely related peptides. Desalanine-desasparagine-insulin, pig proinsulin, hagfish insulin and turkey insulin were respectively 2%, 4%, 2% and 200% as potent as bovine insu...

Variability in dose estimates associated with the food-chain transport and ingestion of selected radionuclides

International Nuclear Information System (INIS)

Hoffman, F.O.; Gardner, R.H.; Eckerman, K.F.

1982-06-01

Dose predictions for the ingestion of 90 Sr and 137 Cs, using aquatic and terrestrial food chain transport models similar to those in the Nuclear Regulatory Commission's Regulatory Guide 1.109, are evaluated through estimating the variability of model parameters and determining the effect of this variability on model output. The variability in the predicted dose equivalent is determined using analytical and numerical procedures. In addition, a detailed discussion is included on 90 Sr dosimetry. The overall estimates of uncertainty are most relevant to conditions where site-specific data is unavailable and when model structure and parameter estimates are unbiased. Based on the comparisons performed in this report, it is concluded that the use of the generic default parameters in Regulatory Guide 1.109 will usually produce conservative dose estimates that exceed the 90th percentile of the predicted distribution of dose equivalents. An exception is the meat pathway for 137 Cs, in which use of generic default values results in a dose estimate at the 24th percentile. Among the terrestrial pathways of exposure, the non-leafy vegetable pathway is the most important for 90 Sr. For 90 Sr, the parameters for soil retention, soil-to-plant transfer, and internal dosimetry contribute most significantly to the variability in the predicted dose for the combined exposure to all terrestrial pathways. For 137 Cs, the meat transfer coefficient the mass interception factor for pasture forage, and the ingestion dose factor are the most important parameters. The freshwater finfish bioaccumulation factor is the most important parameter for the dose prediction of 90 Sr and 137 Cs transported over the water-fish-man pathway

SU-F-I-33: Estimating Radiation Dose in Abdominal Fat Quantitative CT

Energy Technology Data Exchange (ETDEWEB)

Li, X; Yang, K; Liu, B [Massachusetts General Hospital, Boston, MA (United States)

2016-06-15

Purpose: To compare size-specific dose estimate (SSDE) in abdominal fat quantitative CT with another dose estimate D{sub size,L} that also takes into account scan length. Methods: This study complied with the requirements of the Health Insurance Portability and Accountability Act. At our institution, abdominal fat CT is performed with scan length = 1 cm and CTDI{sub vol} = 4.66 mGy (referenced to body CTDI phantom). A previously developed CT simulation program was used to simulate single rotation axial scans of 6–55 cm diameter water cylinders, and dose integral of the longitudinal dose profile over the central 1 cm length was used to predict the dose at the center of one-cm scan range. SSDE and D{sub size,L} were assessed for 182 consecutive abdominal fat CT examinations with mean water-equivalent diameter (WED) of 27.8 cm ± 6.0 (range, 17.9 - 42.2 cm). Patient age ranged from 18 to 75 years, and weight ranged from 39 to 163 kg. Results: Mean SSDE was 6.37 mGy ± 1.33 (range, 3.67–8.95 mGy); mean D{sub size,L} was 2.99 mGy ± 0.85 (range, 1.48 - 4.88 mGy); and mean D{sub size,L}/SSDE ratio was 0.46 ± 0.04 (range, 0.40 - 0.55). Conclusion: The conversion factors for size-specific dose estimate in AAPM Report No. 204 were generated using 15 - 30 cm scan lengths. One needs to be cautious in applying SSDE to small length CT scans. For abdominal fat CT, SSDE was 80–150% higher than the dose of 1 cm scan length.

Estimation of absorbed dose in cell nuclei due to DNA-bound /sup 3/H

Energy Technology Data Exchange (ETDEWEB)

Saito, M; Ishida, M R; Streffer, C; Molls, M

1985-04-01

The average absorbed dose due to DNA-bound /sup 3/H in a cell nucleus was estimated by a Monte Carlo simulation for a model nucleus which was assumed to be spheroidal. The volume of the cell nucleus was the major dose-determining factor for cell nuclei which have the same DNA content and the same specific activity of DNA. This result was applied to estimating the accumulated dose in the cell nuclei of organs of young mice born from mother mice which ingested /sup 3/H-thymidine with drinking water during pregnancy. The values of dose-modifying factors for the accumulated dose due to DNA-bound /sup 3/H compared to the dose due to an assumed homogenous distribution of /sup 3/H in organ were found to be between about 2 and 6 for the various organs.

Can results from animal studies be used to estimate dose or low dose effects in humans

International Nuclear Information System (INIS)

Thomas, J.M.; Eberhardt, L.L.

1981-01-01

A method has been devised to extrapolate biological equilibrium levels between animal species and subsequently to humans. Our initial premise was based on the observation that radionuclide retention is normally a function of metabolism so that direct or indirect measures could be described by a power law based on body weights of test animal species. However, we found that such interspecies comparisons ought to be based on the coefficient of the power equation rather than on the exponential parameter. The method is illustrated using retention data obtained from five non-ruminant species (including humans) that were fed radionuclides with different properties. It appears that biological equilibrium level for radionuclides in man can be estimated using data from mice, rats, and dogs. The need to extrapolate low-dose effects data obtained from small animals (usually rodents) to humans is not unique to radiation dosimetry or radiation protection problems. Therefore, some quantitative problems connected with estimating low-dose effects from other disciplines have been reviewed, both because of the concern about effects induced by the radionuclide moiety of a radiopharmaceutical and those of the nonradioactive component. The possibility of extrapolating low-dose effects calculated from animal studies to human is discussed

Can results from animal studies be used to estimate dose or low dose effects in humans

International Nuclear Information System (INIS)

Thomas, J.M.; Eberhardt, L.L.

1981-01-01

We have devised a method to extrapolate biological equilibrium levels between animal species and subsequently to humans. Our initial premise was based on the observation that radionuclide retention is normally a function of metabolism so that direct or indirect measures could be described by a power law based on body weights of test animal species. However, we found that such interspecies comparisons ought to be based on the coefficient of the power equation rather than on the exponential parameter. The method is illustrated using retention data obtained from five non-ruminant species (including humans) that were fed radionuclides with different properties. It appears that biological equilibrium level for radionuclides in man can be estimated using data from mice, rats and dogs. The need to extrapolate low-dose effects data obtained from small animals (usually rodents) to humans is not unique to radiation dosimetry or radiation protection problems. Therefore, researchers have reviewed some quantitative problems connected with estimating low-dose effects from other disciplines, both because of the concern about effects induced by the radionuclide moiety of a radiopharmaceutical and those of the nonradioactive component. The possibility of extrapolating low-dose effects calculated from animal studies to humans is discussed

Radiation exposure to examiners and patients during therapeutic ERCP: Dose optimisation and risk estimation

International Nuclear Information System (INIS)

Sulieman, A.; Kappas, K.; Theodorou, K.; Paroutoglou, G.; Kapatenakis, A.; Kapsoritakis, A.; Potamianos, S.; Vlychou, M.; Fezoulidis, I.

2008-01-01

Aim: This study intended to optimise the radiation dose during therapeutic ERCP, and to estimate the risk for examiners and patients, to compare the doses based on available data obtained by other researchers and reference levels recommended by international organizations, and to evaluate the technique applied in order to reduce patient and examiners doses. Materials and Methods: 153 patients were studied in two Gastroenterology Departments, (group A, 111; group B, 42). Thermoluminescent dosimeters (TLD) were used to measure the staff and patients entrance surface dose (ESD) at different body sites. Results: The mean ESD, exit and thyroid surface dose per procedure was estimated to be 68.75 mGy, 3.45 mGy and 0.67 mGy, respectively. The mean patient effective dose was 3.44 mSv, and the cancer risk per procedure was estimated to be 190 x10 -6 . The effective dose for the first, second and third examiner was 0.4 μSv, 0.2 μSv and 5.0 μSv, respectively. Conclusion: The patient dose can be optimized by the presence of two experienced examiners and reduction of radiographic images. The examiners should use a wrap around lead apron since the highest dose originating from the X-ray tube, is incident on their side and back. The current formulae, which exist, underestimate the effective dose to the examiners, when they are applied for ERCP procedures. For both patients and examiners, our results were up to 60% lower compared to the lowest values found in previous studies. (authors)

Development of transmission dose estimation algorithm for in vivo dosimetry in high energy radiation treatment

International Nuclear Information System (INIS)

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

2004-01-01

In vivo dosimetry is very important for quality assurance purpose in high energy radiation treatment. Measurement of transmission dose is a new method of in vivo dosimetry which is noninvasive and easy for daily performance. This study is to develop a tumor dose estimation algorithm using measured transmission dose for open radiation field. For basic beam data, transmission dose was measured with various field size (FS) of square radiation field, phantom thickness (Tp), and phantom chamber distance (PCD) with a acrylic phantom for 6 MV and 10 MV X-ray. Source to chamber distance (SCD) was set to 150 cm. Measurement was conducted with a 0.6 cc Farmer type ion chamber. By using regression analysis of measured basic beam data, a transmission dose estimation algorithm was developed. Accuracy of the algorithm was tested with flat solid phantom with various thickness in various settings of rectangular fields and various PCD. In our developed algorithm, transmission dose was equated to quadratic function of log(A/P) (where A/P is area-perimeter ratio) and the coefficients of the quadratic functions were equated to tertiary functions of PCD. Our developed algorithm could estimate the radiation dose with the errors within ±0.5% for open square field, and with the errors within ±1.0% for open elongated radiation field. Developed algorithm could accurately estimate the transmission dose in open radiation fields with various treatment settings of high energy radiation treatment. (author)

Radiation dose estimation from foods due to the accident of TEPCO Fukushima Daiichi Nuclear Power Station

International Nuclear Information System (INIS)

Yamaguchi, Ichiro

2012-01-01

Explained are the purpose of dose assessment, its methods, actual radionuclide levels in food, amounts of food intake, dose estimated hitherto, dose in the future, dose estimated by total food studies, and problems of assessing the dose from food, all of which Tokyo Electric Power Company (TEPCO) Power Station Accident has raised. Dose derived from food can be estimated by the radioactivity measured in each food material and in its combined amounts or in actually cooked food. Amounts of radioactive materials ingested in the body can be measured externally or by bioassay. Japan MHLW published levels of radioactivity in vegetables', fruits, marine products and meats from Mar. 2011, of which time course pattern has been found different each other within and between month(s). Dose due to early exposure in the Accident can be estimated by the radioactivity levels above and data concerning the amounts of food intake summarized by National Institute of Health and Nutrition in 2010 and other institutions. For instance, the thyroid tissue equivalent dose by I-131 in a 1 year old child is estimated to be 1.1-5 mSv depending on the assumed data for calculation, in the first month after the Accident when ICRP tissue equivalent dose coefficient 3.7 x 10-6 Sv/Bq is used. In the future (later than Apr. 2012), new standard limits of radiocesium levels in milk/its products and foods for infant and in other general foods are to be defined 50 and 100 Bq/kg, respectively. The distribution of committed effective doses by radiocesium (mSv/y food intake) are presented as an instance, where it is estimated by 1 million stochastic simulations using 2 covariates of Cs-134, -137 levels (as representative nuclides under regulation) in food and of daily food intake. In dose prediction, conjecturing the behavior of environmental radionuclides and the time of resume of primary industries would be necessary. (T.T.)

Abortion for foetal abnormalities in Ireland; the limited scope of the Irish Government's response to the A, B and C judgment.

Science.gov (United States)

Donoghue, Stephen; Claire-Michelle, Smyth

2013-04-01

Abortion has been a controversial topic in Irish law and one which the Government has been forced to address following the decision of the European Court of Human Rights in A, B and C v. Ireland. The Working Group established to make recommendations have specifically been instructed to deal only with the issues raised in the A, B and C judgment and legislate on the basic of the 'X case'. This restricted approach calls for legalisation of abortion only where the life of the mother is at risk, a position unique only to Ireland and Andorra within Europe. The vast majority of member states to the European Convention on Human Rights allow for legal abortion on the basis of foetal abnormality and with this emerging consensus the margin of appreciation hitherto afforded by the European Court to member states is diminishing. The advancement and availability of non-invasive genetic tests that can determine foetal abnormalities together with the ruling in R. R. v. Poland leaves Ireland in a precarious position for omitting any reference to foetal abnormalities in any proposed legislation.

Effect of Transient Maternal Hypotension on Apoptotic Cell Death in Foetal Rat Brain

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Hamit Özyürek

2014-03-01

Full Text Available Background: Intrauterine perfusion insufficiency induced by transient maternal hypotension has been reported to be associated with foetal brain malformations. However, the effects of maternal hypotension on apoptotic processes in the foetal brain have not been investigated experimentally during the intrauterine period. Aims: The aim of this study was to investigate the effects of transient maternal hypotension on apoptotic cell death in the intrauterine foetal brain. Study Design: Animal experimentation. Methods: Three-month-old female Wistar albino rats were allocated into four groups (n=5 each. The impact of hypoxic/ischemic injury induced by transient maternal hypotension on the 15th day of pregnancy (late gestation in rats was investigated at 48 (H17 group or 96 hours (H19 group after the insult. Control groups underwent the same procedure except for induction of hypotension (C17 and H17 groups. Brain sections of one randomly selected foetus from each pregnant rat were histopathologically evaluated for hypoxic/ischemic injury in the metencephalon, diencephalon, and telencephalon by terminal transferase-mediated dUTP nick end labelling and active cysteine-dependent aspartate-directed protease-3 (caspase-3 positivity for cell death. Results: The number of terminal transferase-mediated dUTP nick end labelling (+ cells in all the areas examined was comparable in both hypotension and control groups. The H17 group had active caspase-3 (+ cells in the metencephalon and telencephalon, sparing diencephalon, whereas the C19 and H19 groups had active caspase-3 (+ cells in all three regions. The number of active caspase-3 (+ cells in the telencephalon in the H19 group was higher compared with the metencephalon and diencephalon and compared with H17 group (p<0.05. Conclusion: Our results suggest that prenatal hypoxic/ischemic injury triggers apoptotic mechanisms. Therefore, blockade of apoptotic pathways, considering the time pattern of the insult, may

Estimation of population dose and risk to holding assistants from veterinary X-ray examination in Japan

International Nuclear Information System (INIS)

Hashizume, Tadashi; Suganuma, Tunenori; Shida, Takuo

1989-01-01

For the estimation of the population doses and risks of stochastic effects to assistants who hold animals during veterinary X-ray examination, a random survey of hospitals and clinics was carried out concerning age distribution of such assistants by groups of facilities. The average organ and tissue dose per examination was evaluated from the experimental data using mean technical factors such as X-ray tube voltage, tube current and field size based on the results of a nationwide survey. The population doses to the assistants were calculated to be about 14 nSv per person per year for the genetically significant dose, 3.5 nSv per person per year for per caput mean marrow dose, 3.3 nSv for the leukemia significant dose and 4.5 nSv for the malignant significant dose, respectively. The total risk of stochastic effects to the Japanese population from holding assistants was estimated using population data and it was estimated to be less than one person per year, but the cancer risks to a number of the assistants were estimated to be more than 4 x 10 -5 . (author)

Small field depth dose profile of 6 MV photon beam in a simple air-water heterogeneity combination: A comparison between anisotropic analytical algorithm dose estimation with thermoluminescent dosimeter dose measurement.

Science.gov (United States)

Mandal, Abhijit; Ram, Chhape; Mourya, Ankur; Singh, Navin

2017-01-01

To establish trends of estimation error of dose calculation by anisotropic analytical algorithm (AAA) with respect to dose measured by thermoluminescent dosimeters (TLDs) in air-water heterogeneity for small field size photon. TLDs were irradiated along the central axis of the photon beam in four different solid water phantom geometries using three small field size single beams. The depth dose profiles were estimated using AAA calculation model for each field sizes. The estimated and measured depth dose profiles were compared. The over estimation (OE) within air cavity were dependent on field size (f) and distance (x) from solid water-air interface and formulated as OE = - (0.63 f + 9.40) x2+ (-2.73 f + 58.11) x + (0.06 f2 - 1.42 f + 15.67). In postcavity adjacent point and distal points from the interface have dependence on field size (f) and equations are OE = 0.42 f2 - 8.17 f + 71.63, OE = 0.84 f2 - 1.56 f + 17.57, respectively. The trend of estimation error of AAA dose calculation algorithm with respect to measured value have been formulated throughout the radiation path length along the central axis of 6 MV photon beam in air-water heterogeneity combination for small field size photon beam generated from a 6 MV linear accelerator.

Haemodynamic preservation in cesarean sections by low dose 0.5% hyperbaric bupivacaine

International Nuclear Information System (INIS)

Ahmad, M.; Ahmad, M.

2017-01-01

Spinal anaesthesia is technique of choice for caesarean sections and hyperbaric bupivacaine is a recommended drug for this popular block. Although safe but few complications are haemodynamic changes, postdural puncture headache, cauda equina syndrome and radiculopathy. However, hypotension remains the common side effect which is believed to occur in 95% of patients resulting in reduction of uteroplacental perfusion causing foetal acid-base abnormalities. Various doses regimes are in safe anaesthesia practice for providing regional anaesthesia for such patients with least detrimental effects on foetal outcome. This study was carried out to find the effective dose of 0.5% hyperbaric bupivacaine in caesarean section patients by comparing two different doses. Methods: After enrolling two hundred patients of C section (Caesarean section) for this study, 90 patients were selected to compare the effects of 0.5% hyperbaric bupivacaine. Group A (n=45) received 10 mg of drug while group B (n=45) received 12 mg for spinal anaesthesia. Onset of block, sensory and motor level, haemodynamic changes, surgery time, maternal satisfaction, APGAR score and incidence of complications were compared in two groups. Results: Blood pressure decreases were less in Group A (p-0.074) but not statistically significant. Phenylephrine for hypotension was given to 17% vs 5% in group B. Maternal satisfaction was found to be better in group B 33 vs 17 but was statistically significant (p 0.034). 2% patients had bradycardia in group A which was treated by atropine. No complications were reported in either group. Conclusion: Doses of hyperbaric bupivacaine for spinal anaesthesia in caesarean sections must be at least 12 mg because it produces excellent anaesthesia and maternal satisfaction without complications. (author)

Prospective estimation of organ dose in CT under tube current modulation

International Nuclear Information System (INIS)

Tian, Xiaoyu; Li, Xiang; Segars, W. Paul; Frush, Donald P.; Samei, Ehsan

2015-01-01

Purpose: Computed tomography (CT) has been widely used worldwide as a tool for medical diagnosis and imaging. However, despite its significant clinical benefits, CT radiation dose at the population level has become a subject of public attention and concern. In this light, optimizing radiation dose has become a core responsibility for the CT community. As a fundamental step to manage and optimize dose, it may be beneficial to have accurate and prospective knowledge about the radiation dose for an individual patient. In this study, the authors developed a framework to prospectively estimate organ dose for chest and abdominopelvic CT exams under tube current modulation (TCM). Methods: The organ dose is mainly dependent on two key factors: patient anatomy and irradiation field. A prediction process was developed to accurately model both factors. To model the anatomical diversity and complexity in the patient population, the authors used a previously developed library of computational phantoms with broad distributions of sizes, ages, and genders. A selected clinical patient, represented by a computational phantom in the study, was optimally matched with another computational phantom in the library to obtain a representation of the patient’s anatomy. To model the irradiation field, a previously validated Monte Carlo program was used to model CT scanner systems. The tube current profiles were modeled using a ray-tracing program as previously reported that theoretically emulated the variability of modulation profiles from major CT machine manufacturers Li et al., [Phys. Med. Biol. 59, 4525–4548 (2014)]. The prediction of organ dose was achieved using the following process: (1) CTDI vol -normalized-organ dose coefficients (h organ ) for fixed tube current were first estimated as the prediction basis for the computational phantoms; (2) each computation phantom, regarded as a clinical patient, was optimally matched with one computational phantom in the library; (3) to

Combined methodology for estimating dose rates and health effects from exposure to radioactive pollutants

Energy Technology Data Exchange (ETDEWEB)

Dunning, D.E. Jr.; Leggett, R.W.; Yalcintas, M.G.

1980-12-01

The work described in the report is basically a synthesis of two previously existing computer codes: INREM II, developed at the Oak Ridge National Laboratory (ORNL); and CAIRD, developed by the Environmental Protection Agency (EPA). The INREM II code uses contemporary dosimetric methods to estimate doses to specified reference organs due to inhalation or ingestion of a radionuclide. The CAIRD code employs actuarial life tables to account for competing risks in estimating numbers of health effects resulting from exposure of a cohort to some incremental risk. The combined computer code, referred to as RADRISK, estimates numbers of health effects in a hypothetical cohort of 100,000 persons due to continuous lifetime inhalation or ingestion of a radionuclide. Also briefly discussed in this report is a method of estimating numbers of health effects in a hypothetical cohort due to continuous lifetime exposure to external radiation. This method employs the CAIRD methodology together with dose conversion factors generated by the computer code DOSFACTER, developed at ORNL; these dose conversion factors are used to estimate dose rates to persons due to radionuclides in the air or on the ground surface. The combination of the life table and dosimetric guidelines for the release of radioactive pollutants to the atmosphere, as required by the Clean Air Act Amendments of 1977.

Estimated collective effective dose to the population from radiological examinations in Slovenia

Science.gov (United States)

Zontar, Dejan; Zdesar, Urban; Kuhelj, Dimitrij; Pekarovic, Dean; Skrk, Damijan

2015-01-01

Background The aim of the study was to systematically evaluate population exposure from diagnostic and interventional radiological procedures in Slovenia. Methods The study was conducted in scope of the “Dose Datamed 2” project. A standard methodology based on 20 selected radiological procedures was adopted. Frequencies of the procedures were determined via questionnaires that were sent to all providers of radiological procedures while data about patient exposure per procedure were collected from existing databases. Collective effective dose to the population and effective dose per capita were estimated from the collected data (DLP for CT, MGD for mammography and DAP for other procedures) using dose conversion factors. Results The total collective effective dose to the population from radiological in 2011 was estimated to 1300 manSv and an effective dose per capita to 0.6 mSv of which approximately 2/3 are due to CT procedures. Conclusions The first systematic study of population exposure to ionising radiation from radiological procedures in Slovenia was performed. The results show that the exposure in Slovenia is under the European average. It confirmed large contributions of computed tomography and interventional procedures, identifying them as the areas that deserve special attention when it comes to justification and optimisation. PMID:25810709

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

International Nuclear Information System (INIS)

Vanhavere, F.

2007-01-01

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

Estimation of population doses from diagnostic medical examinations in Japan, 1974, (4)

International Nuclear Information System (INIS)

Hashizume, Tadashi; Maruyama, Takashi; Kumamoto, Yoshikazu

1976-01-01

In fetus exposed in utero to diagnostic x-rays for the medical examinations of the mother, the absorbed dose has been estimated on the basis of a 1974 nation wide radiological survey. The results of the survey showed that the number of radiographs per year connected with pregnant women was 0.32 million for chest examination excluding mass surveys. 0.29 million for obstetrical examinations including pelvimetry, and 0.21 million for abdominal and pelvic examinations with a total of 0.82 million. The dose absorbed in the fetus was measured with an ionization chamber placed at the hypothetical center of the fetus in an ''average woman'' Rando phantom in which a maternal body was simulated by adding MixDp materials. ''The collective dose'' to the fetus in the pregnant women receiving a given type of examination was calculated from the number of radiographs per year connected with the pregnant women and the fetal doses. The percapita mean marrow dose (CMD), the leukemia significant dose (LSD) and the genetically significant dose (GSD) for the fetus were determined from the collective dose, taking into account the birth expectancy, the child expectancy, life expectancy and significant factor for the fetus. The collective dose to the fetus was estimated to be 9.3 x 10 4 man rad per year. The resultant values of CMD, LSD and GSD were 0.81 mrad per year, 0.79 mrad per person per year and 1.44 mrad per person per year, respectively. (Evans, J.)

Estimation of eye lens doses received by pediatric interventional cardiologists.

Science.gov (United States)

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

2015-09-01

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

Sonographic biophysical profile in detection of foetal hypoxia in 100 cases of suspected high risk pregnancy

International Nuclear Information System (INIS)

Ullah, N.; Khan, A.R.; Usman, M.

2010-01-01

Background: The foetus has become increasingly accessible and visible as a patient over the last two decades. Ultrasound imaging has broadened the scope of foetal assessment. Dynamic real time B-Mode ultrasound is used to monitor cluster of biophysical variables, both dynamic and static collectively termed as biophysical profile. The purpose of this study was to determine the effect of sonographic biophysical profile score on perinatal outcome in terms of mortality and morbidity. Methods: This descriptive study was carried on 100 randomly select ed high risk pregnant patients in Radiology Department PGMI, Government Lady Reading Hospital, Peshawar from December 2007 to June 2008. Manning biophysical profile including non-stress was employed for foetal screening, using Toshiba ultrasound machine model Nemio SSA-550A and 7.5 MHZ probe. Results: Out of 100 cases 79 (79%) had a normal biophysical profile in the last scan of 10/10 and had a normal perinatal outcome with 5 minutes Apgar score >7/10. In 13 (13%) cases Apgar score at 5 minute was < 7/10 and babies were shifted to nursery. There were 2 (2%) false positive cases that showed abnormal biophysical profile scores of 6/10 but babies were born with an Apgar score of 8/10 at 5 minutes. There were 2 (2%) neonatal deaths in this study group. The sensitivity of biophysical profile was 79.1%, specificity 92.9%. Predictive value for a positive test was 98.55%; predictive value for a negative test was 41.93%. Conclusion: Biophysical profile is highly accurate and reliable test of diagnosing foetal hypoxia. (author)

Genetic and environmental factors influencing first service conception rate and late embryonic/foetal mortality in low fertility dairy herds.

Science.gov (United States)

Grimard, B; Freret, S; Chevallier, A; Pinto, A; Ponsart, C; Humblot, P

2006-01-01

The objective of this study was to identify factors affecting variation in conception rate to first artificial inseminations (AI) (CR: number of pregnant cows on D80-100/inseminated cows) and the incidence of embryonic/foetal loss (LEM) between 21 and 80 days of pregnancy (number of cows non-pregnant on D80-100/pregnant on D21) in 44 low fertility dairy herds of the west-central region of France. Reproductive status was assessed using progesterone milk concentration on D0 = Day of AI and D21-24, plasma PSPB concentration on D30-35, rectal palpation on D80-100 and observed return to oestrous. The final data set contained 1285 Prim'Holstein cows, 5.0% (64/1285) were inseminated in the luteal phase (progesterone > or = 3 ng/ml on D0), 61.3% (787/1285) were pregnant on D21-24 (progesterone or = 5 ng/ml on D21-24), 15.4% lost their embryo/foetus between D21-24 and D80-100 (198/1285) and 45.8% (589/1285) were pregnant on D80-100. The incidence of late embryonic/foetal loss (LEM) was 25.2% (198/787). Multivariate logistic regression models including the random herd effect were used to analyse the relationship between AI centre, AI sire, cow's sire, parity, interval between calving and AI, milk production, milk protein content, body condition score (BCS) on D0, season of calving, season of AI, estimated genetic index on CR and LEM incidence. CR was significantly related to parity (p or = 70 days versus > or = 90 days, but the overall effect of the interval was not significant (p = 0.11). LEM incidence was affected by period of AI (p < 0.05), milk production (p < 0.05) and BCS (p < 0.05), but was not related to estimated genetic index. In conclusion, in these low fertility herds, the incidence of LEM was high and 25% of the cows lost their embryo after 21 days of pregnancy. LEM was affected by specific factors (season, BCS), which were not related to CR. The absence of a relationship between estimated genetic index and LEM in spite of its effect on CR indicates that

Estimation of dose distribution in occupationally exposed individuals to FDG-{sup 18}F

Energy Technology Data Exchange (ETDEWEB)

Lacerda, Isabelle V. Batista de; Cabral, Manuela O. Monteiro; Vieira, Jose Wilson, E-mail: ilacerda.bolsista@cnen.gov.br, E-mail: manuela.omc@gmail.com [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Oliveira, Mercia Liane de; Andrade Lima, Fernando R. de, E-mail: falima@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

2014-07-01

The use of unsealed radiation sources in nuclear medicine can lead to important incorporation of radionuclides, especially for occupationally exposed individuals (OEIs) during production and handling of radiopharmaceuticals. In this study, computer simulation was proposed as an alternative methodology for evaluation of the absorbed dose distribution and for the effective dose value in OEIs. For this purpose, the Exposure Computational Model (ECM) which is named as FSUP (Female Adult Mesh - supine) were used. This ECM is composed of: voxel phantom FASH (Female Adult MeSH) in the supine position, the MC code EGSnrc and an algorithm simulator of general internal source. This algorithm was modified to adapt to specific needs of the positron emission from FDG-{sup 18}F. The obtained results are presented as absorbed dose/accumulated activity. To obtain the absorbed dose distribution it was necessary to use accumulative activity data from the in vivo bioassay. The absorbed dose distribution and the value of estimated effective dose in this study did not exceed the limits for occupational exposure. Therefore, the creation of a database with the distribution of accumulated activity is suggested in order to estimate the absorbed dose in radiosensitive organs and the effective dose for OEI in similar environment. (author)

The D1 method: career dose estimation from a combination of historical monitoring data and a single year's dose data

International Nuclear Information System (INIS)

Sont, W.N.

1995-01-01

A method is introduced to estimate career doses from a combination of historical monitoring data and a single year's dose data. This method, called D1 eliminates the bias arising from incorporating historical dose data from times when occupational doses were generally much higher than they are today. Doses calculated by this method are still conditional on the preservation of the status quo in the effectiveness of radiation protection. The method takes into account the variation of the annual dose, and of the probability of being monitored, with the time elapsed since the start of a career. It also allows for the calculation of a standard error of the projected career dose. Results from recent Canadian dose data are presented. (author)

Improved dose estimates for nuclear criticality accidents

International Nuclear Information System (INIS)

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

1995-01-01

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

Current estimates of radiation risks and implications for dose limits

International Nuclear Information System (INIS)

Clarke, R.H.

1989-01-01

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

Long-term intercomparison of Spanish environmental dosimetry services. Study of transit dose estimations

International Nuclear Information System (INIS)

Duch, Ma Amor; Carlos Saez-Vergara, Jose; Ginjaume, Merce; Gomez, Candelas; Maria Gonzalez-Leiton, Ana; Herrero, Javier; Jose de Lucas, Ma; Rodriguez, Rafael; Marugan, Immaculada; Salas, Rosario

2008-01-01

This paper presents the layout and results of a three-year follow-up of a national intercomparison campaign organized on a voluntary basis among the Spanish Laboratories in charge of environmental monitoring at and in the vicinity of Spanish nuclear installations. The dosemeters were exposed in the field at an environmental reference station with a known ambient dose equivalent, and controlled meteorological parameters. The study aimed at verifying the consistency of the different laboratories in estimating the ambient dose equivalent in realistic fields and to evaluate the influence of two different procedures to estimate the transit dose during the transfer of the dosemeters both from and to the dosimetric laboratory and the monitored site. All the results were within 20% of the reference doses for all the dosemeters tested, and in most cases they were within 10%

Estimation of breast dose and cancer risk in chest and abdomen CT procedures

International Nuclear Information System (INIS)

Eltahir, Suha Abubaker Ali

2013-05-01

The use of CT in medical diagnosis delivers radiation doses to patents that are higher than those from other radiological procedures. Lack of optimized protocols be an additional source of increased dose in developing countries. The aims of this study are first, to measure patient doses during CT chest and abdomen procedures, second, to estimate the radiation dose to the breast, and third to quantify the radiation risks during the procedures. Patient doses from two common CT examinations were obtained from four hospitals in Khartoum.The patient doses were estimated using measurement of CT dose indexes (CTDI), exposure-related parameters, and the IMPACT spreadsheet based on NRPB conversion factors. A large variation of mean organ doses among hospitals was observed for similar CT examinations. These variations largely originated from different CT scanning protocols used in different hospitals and scanner type. The largest range was found for CT of the chest, for which the dose varied from 2.3 to 47 (average 24.7) mSv and for abdomen CT, it was 1.6 to 18.8 (average 10.2) mSv. Radiation dose to the breast ranged from 1.6 to 32.9 mSv for the chest and 1.1 to 13.2 mSv for the abdomen. The radiation risk per procedure was high. The obtained values were mostly higher than the values of organ doses reported from the other studies. It was concluded that current clinical chest and abdomen protocols result in variable radiation doses to the breast. The magnitude of exposure may have implications for imaging strategies.(Author)

Estimation of radionuclide ingestion: Lessons from dose reconstruction for fallout from the Nevada Test Site

International Nuclear Information System (INIS)

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

1994-01-01

The United States conducted atmospheric testing of nuclear devices at the Nevada Test Site from 1951 through 1963. In 1979 the U.S. Department of Energy established the Off-Site Radiation Exposure Review Project to compile a data base related to health effects from nuclear testing and to reconstruct doses to public residing off of the Nevada Test Site. This project is the most comprehensive dose reconstruction project to date, and, since similar assessments are currently underway at several other locations within and outside the U.S., lessons from ORERP can be valuable. A major component of dose reconstruction is estimation of dose from radionuclide ingestion. The PATHWAY food-chain model was developed to estimate the amount of radionuclides ingested. For agricultural components of the human diet, PATHWAY predicts radionuclide concentrations and quantities ingested. To improve accuracy and model credibility, four components of model analysis were conducted: estimation of uncertainty in model predictions, estimation of sensitivity of model predictions to input parameters, and testing of model predictions against independent data (validation), and comparing predictions from PATHWAY with those from other models. These results identified strengths and weaknesses in the model and aided in establishing the confidence associated with model prediction, which is a critical component risk assessment and dose reconstruction. For fallout from the Nevada Test Site, by far, the largest internal doses were received by the thyroid. However, the predicted number of fatal cancers from ingestion dose was generally much smaller than the number predicted from external dose. The number of fatal cancers predicted from ingestion dose was also orders of magnitude below the normal projected cancer rate. Several lessons were learned during the study that are relevant to other dose reconstruction efforts

PTTL Dose Re-estimation Applied to Quality Control in TLD-100 Based Personal Dosimetry

International Nuclear Information System (INIS)

Muniz, J.L.; Correcher, V.; Delgado, A.

1999-01-01

A new method for quality control of dose performance in Personal Dosimetry using TLD-100 is presented. This method consists of the application of dose reassessment techniques based on phototransferred thermoluminescence (PTTL). Reassessment is achieved through a second TL readout of the dosemeters worn by the controlled workers, after a reproducible UV exposure. Recent refinements in the PTTL technique developed in our laboratory allow reassessing doses as low as 0.2 mSv, thus extending the reassessment capability to the entire dose range that must be monitored in personal dosimetry. After a one month exposure, even purely environmental doses can be reassessed. This method can be applied for either re-estimation of single doses or of the total dose accumulated after a number of exposures and dose measurements. Several tests to reconfirm low doses in normal working conditions for personal dosimetry have been performed. Each test consisted of several cycles of exposure and TL evaluations and a final PTTL re-estimation of the total accumulated dose in those cycles. The results obtained always showed very good agreement between the sum of the partial doses and the total reassessed dose. The simplicity of the method and the possibility of re-evaluating the doses assessed to the workers employing their own dosemeters are advantageous features to be considered in designing systems for the determination of real performance in personal dosimetry. (author)

Estimates of effective equivalent dose commitments for Slovene population following the Chernobyl accident

International Nuclear Information System (INIS)

Kanduc, M.; Jovanowic, O.; Kuhar, B.

2004-01-01

This paper shows the estimates of effective equivalent dose commitments for the two groups of Slovene population, 5 years old children and adults. Doses were calculated on the basis of the ICRP 30 methodology, first from the measurements of the concentrations of the radionuclides in air, water and food samples and then compared with the results of the measurements of radionuclides in composite samples of the prepared food, taken in the kindergarten nearby. Results show that there is certain degree of conservatism hidden in the calculation of the doses on the basis of measurements of the activity concentration in the elements of the biosphere and is estimated to be roughly 50%. (author)

Biopsychosocial effects of foetal alcohol syndrome among children from the Interventional Care Facility in Otwock

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Aneta Sęk

2017-06-01

Full Text Available Objective: The aim of the study was to present the biopsychosocial effects of foetal alcohol syndrome among the children from the Interventional Care Facility in Otwock in the years 2012–2015. Material and methods: We analysed medical records from the years 2012 to 2015. Medical documentation consisted of the child’s stay record, psychological diagnosis, maternal interview, social interview, a round check report, medical assessment and consultation records, neurological examination reports and physiotherapist reports. The study included medical documentation of 18 girls (29% and 44 boys (71%. In total, 62 children aged between 3 days and 1 year were included in the study group. Results: Consumption of alcohol during pregnancy is still declared by many women (69%, including 44% of mothers consuming alcohol throughout the duration of pregnancy. All children in the Interventional Care Facility had at least 2 dysmorphic facial features. Sucking dysfunction, which caused difficulty when feeding, was observed in 59 children, and dysaesthesia – in 56 children. Children with foetal alcohol syndrome were very tearful, experienced tensions (58 children, hyperactivity (59 children as well as sleep disorders (60 children. They frequently experienced emotional disorders (60 children and problems with establishing contact with other people (44 children. Conclusions: It was found that alcohol has teratogenic effects on the developing foetus. Any amount of alcohol consumed by a pregnant woman can cause damage to the foetus. Foetal exposure to alcohol leads to multiple disorders that occur not only in the biological, but also in the psychological sphere. The study confirmed that children with foetal alcohol syndrome suffer from multiple health problems and have difficulty functioning in society due to their “otherness”.

Dose rate estimation of the Tohoku hynobiid salamander, Hynobius lichenatus, in Fukushima.

Science.gov (United States)

Fuma, Shoichi; Ihara, Sadao; Kawaguchi, Isao; Ishikawa, Takahiro; Watanabe, Yoshito; Kubota, Yoshihisa; Sato, Youji; Takahashi, Hiroyuki; Aono, Tatsuo; Ishii, Nobuyoshi; Soeda, Haruhi; Matsui, Kumi; Une, Yumi; Minamiya, Yukio; Yoshida, Satoshi

2015-05-01

The radiological risks to the Tohoku hynobiid salamanders (class Amphibia), Hynobius lichenatus due to the Fukushima Dai-ichi Nuclear Power Plant accident were assessed in Fukushima Prefecture, including evacuation areas. Aquatic egg clutches (n = 1 for each sampling date and site; n = 4 in total), overwintering larvae (n = 1-5 for each sampling date and site; n = 17 in total), and terrestrial juveniles or adults (n = 1 or 3 for each sampling date and site; n = 12 in total) of H. lichenatus were collected from the end of April 2011 to April 2013. Environmental media such as litter (n = 1-5 for each sampling date and site; n = 30 in total), soil (n = 1-8 for each sampling date and site; n = 31 in total), water (n = 1 for each sampling date and site; n = 17 in total), and sediment (n = 1 for each sampling date and site; n = 17 in total) were also collected. Activity concentrations of (134)Cs + (137)Cs were 1.9-2800, 0.13-320, and 0.51-220 kBq (dry kg) (-1) in the litter, soil, and sediment samples, respectively, and were 0.31-220 and <0.29-40 kBq (wet kg)(-1) in the adult and larval salamanders, respectively. External and internal absorbed dose rates to H. lichenatus were calculated from these activity concentration data, using the ERICA Assessment Tool methodology. External dose rates were also measured in situ with glass dosimeters. There was agreement within a factor of 2 between the calculated and measured external dose rates. In the most severely contaminated habitat of this salamander, a northern part of Abukuma Mountains, the highest total dose rates were estimated to be 50 and 15 μGy h(-1) for the adults and overwintering larvae, respectively. Growth and survival of H. lichenatus was not affected at a dose rate of up to 490 μGy h(-1) in the previous laboratory chronic gamma-irradiation experiment, and thus growth and survival of this salamander would not be affected, even in the most severely contaminated habitat in Fukushima Prefecture. However, further

Reevaluation of nasal swab method for dose estimation at nuclear emergency accident

International Nuclear Information System (INIS)

Yamada, Yuji; Fukutsu, Kumiko; Kurihara, Osamu; Akashi, Makoto

2008-01-01

ICRP Publication 66 human respiratory tract model has been used extensively over in exposure dose assessment. It is well known that respiratory deposition efficiency of inhaled aerosol and its deposition region strongly depend on the particle size. In most of exposure accidents, however, nobody knows a size of inhaled aerosol. And thus two default aerosol sizes of 5μ in AMAD for the workers and 1μ in AMAD for the public are given as being representative in the ICRP model, but both sizes are not linked directly to the maximum dose. In this study, the most hazardous size to our health effects and how to estimate an intake activity was discussed from a viewpoint of emergency medicine. In exposure accident of alpha emitter such as Pu-239, lung monitor and bioassay measurements are not the best methods for rapid estimation with high sensitivity, so that an applicability of nasal swab method has been investigated. A computer software, LUDEP, was used in the calculation of respiratory deposition. It showed that the effective dose per unit intake activity strongly depended on the inhaled aerosol size. In case of Pu-239 dioxide aerosols, it was confirmed that the maximum of dose conversion factor was observed around 0.01μ. It means that this 0.01μ is the most hazardous size at exposure accident of Pu-239. From analysis of the relationship between AI and ET l deposition, it was found that the dose conversion factor from the activity deposited in ET l region also was affected by the aerosol size. The usage of the ICRP's default size in nasal swab method might cause obvious underestimation of the intake activity. Dose estimation based on nasal swab method is possible from safety side at nuclear emergency, and the availability in quantity should be reevaluated for emergency medicine considering of chelating agent administration. (author)

The impact of delayed maternity on foetal growth in Spain: An assessment by population attributable fraction.

Science.gov (United States)

Varea, Carlos; Terán, José Manuel; Bernis, Cristina; Bogin, Barry

2017-09-18

Delayed childbearing is considered a risk factor for maternal-foetal health. As in other higher-income countries, in Spain age at maternity has steadily increased during the last two decades. To quantify the impact of the delay in the age at maternity on small for gestational age (SGA) categories of maternity and parity. Primipara 35-39 years old mothers have the highest PAF p in the three categories of SGA, with the maximum value for SGA maternity is a significant adjusted risk factor for SGA, contributing to the increase of its prevalence. However, results also suggest a limited clinical impact of delayed maternity on foetal growth. Positive changes in maternal profile associated with the shift in maternal age might contribute to explain the limited impact of mothers aged 35 years and older on negative birth outcome in Spain. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Estimation dose in patients of nuclear medicine. Implementation of a calculi program and methodology

International Nuclear Information System (INIS)

Prieto, C.; Espana, M.L.; Tomasi, L.; Lopez Franco, P.

1998-01-01

Our hospital is developing a nuclear medicine quality assurance program in order to comply with medical exposure Directive 97/43 EURATOM and the legal requirements established in our legislation. This program includes the quality control of equipment and, in addition, the dose estimation in patients undergoing nuclear medicine examinations. This paper is focused in the second aspect, and presents a new computer program, developed in our Department, in order to estimate the absorbed dose in different organs and the effective dose to the patients, based upon the data from the ICRP publication 53 and its addendum. (Author) 16 refs

Methods for estimation of internal dose of the public from dietary

International Nuclear Information System (INIS)

Zhu Hongda

1987-01-01

Following the issue of its Publication 26, ICRP has successively published its Publication 30 to meet the great changes and improvements made in the Basic Recommendations since July of 1979. In Part 1 of Publcation 30, ICRP recommended a new method for internal dose estimation and pressented some important data. In this report, comparison is made among methods for estimation of internal dose for the public from dietary. They include: (1) the new method suggested by ICRP; (2) the simple and convenient method using transfer factors under equilibrium conditions; (3) the methods based on the similarities of several radionuclides to their chemical analogs. It is concluded that the first method is better than the others and should be used from now on

Estimate of absorbed dose received by individuals irradiated with neutrons

International Nuclear Information System (INIS)

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

1995-01-01

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

The effect of volume-of-interest misregistration on quantitative planar activity and dose estimation

International Nuclear Information System (INIS)

Song, N; Frey, E C; He, B

2010-01-01

In targeted radionuclide therapy (TRT), dose estimation is essential for treatment planning and tumor dose response studies. Dose estimates are typically based on a time series of whole-body conjugate view planar or SPECT scans of the patient acquired after administration of a planning dose. Quantifying the activity in the organs from these studies is an essential part of dose estimation. The quantitative planar (QPlanar) processing method involves accurate compensation for image degrading factors and correction for organ and background overlap via the combination of computational models of the image formation process and 3D volumes of interest defining the organs to be quantified. When the organ VOIs are accurately defined, the method intrinsically compensates for attenuation, scatter and partial volume effects, as well as overlap with other organs and the background. However, alignment between the 3D organ volume of interest (VOIs) used in QPlanar processing and the true organ projections in the planar images is required. The aim of this research was to study the effects of VOI misregistration on the accuracy and precision of organ activity estimates obtained using the QPlanar method. In this work, we modeled the degree of residual misregistration that would be expected after an automated registration procedure by randomly misaligning 3D SPECT/CT images, from which the VOI information was derived, and planar images. Mutual information-based image registration was used to align the realistic simulated 3D SPECT images with the 2D planar images. The residual image misregistration was used to simulate realistic levels of misregistration and allow investigation of the effects of misregistration on the accuracy and precision of the QPlanar method. We observed that accurate registration is especially important for small organs or ones with low activity concentrations compared to neighboring organs. In addition, residual misregistration gave rise to a loss of precision

Retrospective methods to estimate radiation dose at the site of breast cancer development after Hodgkin lymphoma radiotherapy

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Nicola S. Russell

2017-12-01

Full Text Available Background: An increased risk of breast cancer following radiotherapy for Hodgkin lymphoma (HL has now been robustly established. In order to estimate the dose–response relationship more accurately, and to aid clinical decision making, a retrospective estimation of the radiation dose delivered to the site of the subsequent breast cancer is required. Methods: For 174 Dutch and 170 UK female patients with breast cancer following HL treatment, the 3-dimensional position of the breast cancer in the affected breast was determined and transferred onto a CT-based anthropomorphic phantom. Using a radiotherapy treatment planning system the dose distribution on the CT-based phantom was calculated for the 46 different radiation treatment field set-ups used in the study population. The estimated dose at the centre of the breast cancer, and a margin to reflect dose uncertainty were determined on the basis of the location of the tumour and the isodose lines from the treatment planning. We assessed inter-observer variation and for 47 patients we compared the results with a previously applied dosimetry method. Results: The estimated median point dose at the centre of the breast cancer location was 29.75 Gy (IQR 5.8–37.2, or about 75% of the prescribed radiotherapy dose. The median dose uncertainty range was 5.97 Gy. We observed an excellent inter-observer variation (ICC 0.89 (95% CI: 0.74–0.95. The absolute agreement intra-class correlation coefficient (ICC for inter-method variation was 0.59 (95% CI: 0.37–0.75, indicating (nearly good agreement. There were no systematic differences in the dose estimates between observers or methods. Conclusion: Estimates of the dose at the point of a subsequent breast cancer show good correlation between methods, but the retrospective nature of the estimates means that there is always some uncertainty to be accounted for. Keywords: Retrospective dosimetry, Hodgkin lymphoma, Breast carcinogenesis