scholarly journals Der Einfluß von Röntgenstrahlen auf Ophryotrocha puerilis

1965 ◽  
Vol 20 (4) ◽  
pp. 350-355
Author(s):  
A. L. Grierson ◽  
H. Querner
Keyword(s):  
Mortality Rate ◽  
Radiation Dose ◽  
Total Dose ◽  
Growth Zone ◽  
Radiation Doses ◽  
Effects Of Radiation ◽  
Sexually Mature

The polychaet, Ophryotrodia puerilis, which is easily bred in the laboratory, lends itself well to research on the effects of radiation on invertebrates. Growth, which depends on the activity of a growth zone, is accomplished by the addition of segments. It is, therefore, easily recorded quantitatively. Radiation doses up to 100,000 r (3335 r/min) were used. The effect of the radiation depends on the size of animal. In animals of 20 segments the LD 50/30 dose is about 50,000 r; in animals of 10 segments doses of 20,000 r and greater completely inhibit growth, and doses of 10,000 r inhibit the growth of smaller animals. Animals with 10 segments slight retardation of growth after 5,000 and 10,000 r, while the smaller animals do not grow after 10,000 r of radiation and have their growth significantly retarded by 5,000 r. — Eggs laid by sexually mature females treated with 50,000 r fail to develop. After 20,000 and 10,000 r the eggs laid in the first 10 days do not develop but eggs exposed later are capable of develpoment. Animals of 10 segments are fertile after 10,000 r but sterile after 20,000 r. — Fractionation of the radiation dose decreases the mortality rate and, with a total dose of 20,000 r, allows growth. — Irradiation of eggs has an effect that is dependent on the age of the embryo. Up to 9 days 1000 r are lethal; from 10 days on 2000 r have no effect on development. Irradiation with 500 r shows no effect, while two 250 r increments of dose given 48 hours apart kill eggs 2 — 10 days old.

Effects of radiation dose and nitrogen purge on collagen scaffold properties

2021 ◽  
pp. 088532822110476
Author(s):  
Nicholas J Sant ◽  
Benedikt L Proffen ◽  
Martha M Murray
Keyword(s):  
Radiation Dose ◽  
Enzymatic Degradation ◽  
Early Stage ◽  
Collagen Scaffold ◽  
Radiation Doses ◽  
Collagen Scaffolds ◽  
Banding Patterns ◽  
Soluble Collagen ◽  
Mass Fractions ◽  
Effects Of Radiation

Sterilization of medical devices is commonly performed using radiation methods. However, collagen materials can be damaged when using standard radiation doses (25 kGy). Small increases of radiation dose can allow for increases in the acceptable initial bioburden load of aseptically manufactured devices while maintaining required sterility assurance levels, which is often critical in early stage translational settings. In this study, we hypothesized that small increases in radiation dose from 15 to 20 kGy would result in significant changes to several key characteristics of collagen scaffolds. Scaffolds were manufactured by lyophilizing the pepsin digest of dense bovine connective tissue in cylindrical molds and were irradiated at either 0, 15, 17.5, or 20 kGy with an additional group packaged in nitrogen and irradiated at 17.5 kGy. Groups were evaluated for changes to the soluble collagen and glycosaminoglycan mass fractions, protein banding patterns in electrophoresis, a collagen fragmentation assay, and resistance to enzymatic degradation. All parameters were statistically analyzed using one-way analysis of variance with Tukey’s correction for multiple comparisons. The soluble collagen mass fraction was significantly decreased in the 20 kGy group; however, there was no significant effect of radiation dose or a nitrogen-rich environment on the other measured parameters, including protein banding patterns, fragmented collagen content, and resistance to enzymatic degradation. Statement of Clinical Significance: Collagen scaffolds have proven useful in clinical applications but can be damaged by standard radiation doses. Low-dose sterilization may be a viable alternative that minimally impacts key properties of these scaffolds.

EFFECTIVE RADIATION DOSE OF 18F-FDG PET/CT: HOW MUCH DOES DIAGNOSTIC CT CONTRIBUTE?

2019 ◽  
Vol 187 (2) ◽  
pp. 183-190 ◽  
Author(s):  
Yuhao Li ◽  
Lisha Jiang ◽  
Haitao Wang ◽  
Huawei Cai ◽  
Yongzhao Xiang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Total Dose ◽  
Radiation Doses ◽  
Effective Radiation Dose ◽  
Positron Emission ◽  
Pet Ct ◽  
Effective Doses ◽  
Fdg Pet Ct ◽  
Effective Radiation

Abstract The aim was to estimate the effective doses associated with different types of scanning protocols and how much the diagnostic computed tomography (DCT) scan contributed to the total dose of the dual-modality positron emission tomography/computed tomography (PET/CT) examinations. The results showed that an average radiation dose of 8.19 ± 0.83 mSv and 13.44 ± 5.14 mSv for the PET and CT components, respectively, resulting in a total dose of 21.64 ± 5.20 mSv. Approximately 92.7% (980 of 1057) of the patients underwent additional DCT protocols. The DCT protocols contributed 42% of the overall effective radiation doses, which was larger than the percentage contributed by the PET component (38%) and LCT protocols (20%). Reducing the diagnostic area of the DCT scans that patients undergo and decreasing the use of chest-abdomen-pelvis (CAP), abdomen-pelvis (AP) and chest DCT protocols, especially the CAP protocol, will be helpful in decreasing the effective radiation doses of PET/CT scan.

scholarly journals Antitumor effect of radiation therapy on orthotopic PDX models of human esophageal adenocarcinoma

2021 ◽  
Author(s):  
AA Kiblitskaya ◽  
AS Goncharova ◽  
AE Anisimov ◽  
AV Snezhko ◽  
SN Dimitriadi ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Total Dose ◽  
Esophageal Adenocarcinoma ◽  
Tumor Volume ◽  
Survival Rates ◽  
Growth Delay ◽  
Control Group ◽  
Radiation Doses ◽  
Immunodeficient Mice ◽  
Orthotopic Xenografts

As a rule, esophageal adenocarcinoma develops in the lower esophagus. Life expectancy and survival rates depend on the cancer stage and the general health of the patient. Chemoradiotherapy is the most successful treatment approach to this type of cancer. The choice of optimal radiation doses for achieving the best possible therapeutic effect is still a challenge. The aim of this paper was to study effective radiation doses and assess response of human esophageal adenocarcinoma to radiation using a PDX model. The study was conducted in female Balb/c nude mice (n = 25). Fragments of the donor tumor were implanted into the cervical esophagus of immunodeficient mice. Effects of radiation on the obtained orthotopic xenografts were studied after each of 3 irradiation sessions (4, 6, 8, and 10 Gy in each of the experimental groups, respectively). First-passage xenografts reproduced the morphology of the donor tumor. The mean tumor volume differed significantly between the control group and the experimental groups exposed to 6, 8 or 10 Gy (р ≤ 0.01) after each irradiation session. Tumor growth delay was significant after exposure to the total dose of 18 Gy. The further radiation dose increase was ineffective. The reduction of tumor volume in the xenografts was correlated to the increase in the one-time radiation dose. The total dose over 18 Gy produced a detrimental effect on the hematopoietic system and blood biochemistry of the experimental mice.

The Employment of 197Hg EDTA in Kidney Scanning

1965 ◽  
Vol 05 (01) ◽  
pp. 56-67
Author(s):  
I. Pál ◽  
J. Földes ◽  
I. Krasznai
Keyword(s):  
Radiation Dose ◽  
Renal Cortex ◽  
Radiation Doses ◽  
Intravenous Pyelography ◽  
Edta Complex

SummaryThe authors investigated the use of 197Hg EDTA complex for kidney scanning. They describe the physical, biological and toxicological properties of the compound; its distribution within the organism, its excretion with urine and faeces and its uptake by the kidneys. The authors have established that the renal cortex selectively secretes the material which makes it suitable for kidney scanning. Some scintigrams of both normal and pathologic kidneys are presented.Finally a detailed discussion of the dosimetry is included. The radiation doses due to 197Hg EDTA are compared with those due to 203Hg-neohydrin and to intravenous pyelography. This comparison shows clearly that the use of 197Hg EDTA considerably decreases the radiation dose to the patient.

Radiation Minimisation and Outcome Maximisation in Cardiac Computed Tomograpy

2010 ◽  
Vol 6 (1) ◽  
pp. 15
Author(s):  
James P Earls ◽  
Jonathon A Leipsic ◽  
◽  
Keyword(s):  
Radiation Dose ◽  
Dose Reduction ◽  
New Technologies ◽  
Cardiac Computed Tomography ◽  
Substantial Reduction ◽  
Radiation Doses ◽  
Tube Current ◽  
Prospective Triggering ◽  
Effective Radiation ◽  
Selection Of

Recent reports have raised general awareness that cardiac computed tomography (CT) has the potential for relatively high effective radiation doses. While the actual amount of risk this poses to the patient is controversial, the increasing concern has led to a great deal of research on new CT techniques capable of imaging the heart at substantially lower radiation doses than was available only a few years ago. Methods of dose reduction include optimised selection of user-defined parameters, such as tube current and voltage, as well as use of new technologies, such as prospective triggering and iterative reconstruction. These techniques have each been shown to lead to substantial reduction in radiation dose without loss of diagnostic accuracy. This article will review the most frequently used and widely available methods for radiation dose reduction in cardiac CT and give practical advice on their use and limitations.

scholarly journals Optimal Radiation Dose For Stage III Lung Cancer – Should “Definitive” Radiation Doses Be Used in the Pre-Operative Setting?

2021 ◽  
pp. 100201
Author(s):  
Areo G. Saffarzadeh ◽  
Maureen Canavan ◽  
Benjamin J. Resio ◽  
Samantha L. Walters ◽  
Kaitlin M. Flores ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Radiation Dose ◽  
Stage Iii ◽  
Radiation Doses

Diagnostic Reference Levels for Common Orthopedic Hand and Wrist Procedures Using Intraoperative mini C-arm Fluoroscopy

Hand ◽  
2021 ◽  
pp. 155894472199425
Author(s):  
Kiran R. Madhvani ◽  
Matthew J. R. Clark ◽  
Alex A. J. Kocheta
Keyword(s):  
Radiation Dose ◽  
Fracture Fixation ◽  
Wrist Fracture ◽  
Radiation Doses ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Audit Data ◽  
Small Joint ◽  
Open Fixation ◽  
Phalangeal Fracture

Background: Diagnostic reference levels are radiation dose levels in medical radiodiagnostic practices for typical examinations for groups of standard-sized individuals for broadly defined types of equipment. This study aimed to contribute to national diagnostic reference levels for common hand and wrist procedures using mini C-arm fluoroscopy. Small joint and digital fracture procedure diagnostic reference levels have not been reported in significant numbers previously with procedure-level stratification. Methods: Data were collected from fluoroscopy logbooks and were cross-referenced against the audit log kept on fluoroscopy machines. A total of 603 procedures were included. Results: The median radiation dose for wrist fracture open fixation was 2.73 cGycm2, Kirschner wiring (K-wiring) procedures was 2.36 cGycm2, small joint arthrodesis was 1.20 cGycm2, small joint injections was 0.58 cGycm2, and phalangeal fracture fixation was 1.05 cGycm2. Conclusions: Wrist fracture fixation used higher radiation doses than phalangeal fracture fixation, arthrodeses, and injections. Injections used significantly less radiation than the other procedures. There are significant differences in total radiation doses when comparing these procedures in hand and wrist surgery. National and international recommendations are that institutional audit data should be collected regularly and should be stratified by procedure type. This study helps to define standards for this activity by adding to the data available for wrist fracture diagnostic reference levels and defining standards for digital and injection procedures.

Estimation of Radiation Doses in X-Ray Visualization of Biological Objects

2014 ◽  
Vol 880 ◽  
pp. 53-56 ◽  
Author(s):  
Sergei Stuchebrov ◽  
Andrey Batranin ◽  
Dan Verigin ◽  
Yelena Lukyanenko ◽  
Maria Siniagina ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Biological Object ◽  
Gas Discharge ◽  
Radiation Doses ◽  
Semiconductor Detectors ◽  
Interior Structure ◽  
Dose Calculations ◽  
Object Control ◽  
X Ray ◽  
Biological Objects

Two setups for X-ray visualization of objects interior structure were designed and assembled in TPU. These radiographic systems are based on linear gas-discharge and GaAs semiconductor detectors. During investigation of biological object control of radiation doses has a high priority. In this report radiation dose calculations in X-ray visualization are presented. These calculation also includes dose calculations of sinograms which are used for reconstruction of tomography slices.

scholarly journals Low-Dose Computed Tomography for the Optimization of Radiation Dose Exposure in Patients with Crohn’s Disease

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Richard G. Kavanagh ◽  
John O’Grady ◽  
Brian W. Carey ◽  
Patrick D. McLaughlin ◽  
Siobhan B. O’Neill ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Crohn’S Disease ◽  
Image Quality ◽  
Crohn's Disease ◽  
Radiation Dose ◽  
Ionizing Radiation ◽  
Low Dose ◽  
Radiation Doses ◽  
Radiation Dose Exposure ◽  
Ct Technology

Magnetic resonance imaging (MRI) is the mainstay method for the radiological imaging of the small bowel in patients with inflammatory bowel disease without the use of ionizing radiation. There are circumstances where imaging using ionizing radiation is required, particularly in the acute setting. This usually takes the form of computed tomography (CT). There has been a significant increase in the utilization of computed tomography (CT) for patients with Crohn’s disease as patients are frequently diagnosed at a relatively young age and require repeated imaging. Between seven and eleven percent of patients with IBD are exposed to high cumulative effective radiation doses (CEDs) (>35–75 mSv), mostly patients with Crohn’s disease (Newnham E 2007, Levi Z 2009, Hou JK 2014, Estay C 2015). This is primarily due to the more widespread and repeated use of CT, which accounts for 77% of radiation dose exposure amongst patients with Crohn’s disease (Desmond et al., 2008). Reports of the projected cancer risks from the increasing CT use (Berrington et al., 2007) have led to increased patient awareness regarding the potential health risks from ionizing radiation (Coakley et al., 2011). Our responsibilities as physicians caring for these patients include education regarding radiation risk and, when an investigation that utilizes ionizing radiation is required, to keep radiation doses as low as reasonably achievable: the “ALARA” principle. Recent advances in CT technology have facilitated substantial radiation dose reductions in many clinical settings, and several studies have demonstrated significantly decreased radiation doses in Crohn’s disease patients while maintaining diagnostic image quality. However, there is a balance to be struck between reducing radiation exposure and maintaining satisfactory image quality; if radiation dose is reduced excessively, the resulting CT images can be of poor quality and may be nondiagnostic. In this paper, we summarize the available evidence related to imaging of Crohn’s disease, radiation exposure, and risk, and we report recent advances in low-dose CT technology that have particular relevance.

scholarly journals SOME ISSUES OF LIFE ACTIVITIES OF POPULATION IN THE CHORNOBYL EXCLUSION ZONE IN UKRAINE

2021 ◽  
Vol 26 ◽  
pp. 141-161
Author(s):  
N. Gunko ◽  
◽  
O. Ivanova ◽  
K. Loganovsky ◽  
N. Korotkova ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Radiation Dose ◽  
Nuclear Power ◽  
Radiation Doses ◽  
Total Radiation ◽  
Exclusion Zone ◽  
Permanent Residence ◽  
Total Radiation Dose ◽  
Effective Radiation

Background. Radiation accidents at the Chornobyl Nuclear Power Plant (USSR, 1986) and Fukushima-1 (Japan, 2011) have shown that global environmental contamination is an intervention in normal human life making negative effect on population health. These accidents highlighted a number of statutory and regulatory both with medical and social problems for individuals, who returned voluntarily for permanent residence in the Chornobyl Exclusion Zone i.e. a radiation-hazardous area (they are named the «self-settlers»). Objective: generalization of experience in the settlement of normative-legal, ecological-dosimetric and medicosocial life issues of population living in the Chornobyl NPP (ChNPP) Exclusion Zone («self-settlers»). Object and methods. The chosen problem is complex, necessitating the generalization of radiation-hygienic, medical-biological, socio-economic, demographic and sociological research results obtained by the national and foreign authors. A set of theoretical research and analysis of empirical data methods on the principles of interdisciplinary interaction was used; the systematic, legal, economic, medical-biological, demographic and retrospective-dosimetric approaches of research were applied. Results. It was shown that a part of population refused to evacuate or had returned for permanent residence to the radiation-hazardous lands after the ChNPP accident. In 1986–2009 the number of «self-settlers» ranged from 150 to 2,000 in different years. In 2021 – the 101 people. Those were mainly people of working age, mostly females, single people or widows/widowers. Рrevious medical and dosimetric studies have shown that long-term residence in the Exclusion Zone affects physical and mental health of «self-settlers» and causes atypical aging, including involvement of the central nervous system. According to calculations, the average effective total radiation dose accumulated by «self-settlers» for the first 3 years was 30 % of dose for the entire post-accident period, and the dose accumulated over 20 years was 54 % of the dose accumulated over 35 years. But the effective radiation doses accumulated in different periods after the accident differ significantly in residents of different Exclusion Zone settlements. This information needs further study in terms of the «radiation dose - health status» dependence. Conclusions. The effective radiation doses accumulated in different periods after the accident differ significantly in the residents of different Exclusion Zone settlements. Тhe average effective total radiation dose accumulated by «self-settlers» for the first 3 years was 30 % of the dose for the entire post-accident period, and the dose accumulated over 20 years was 54 % of the dose accumulated over 35 years. The Scientific Council meeting of NAMS approved the NRCRM Annual Report. Key words: Chornobyl Nuclear Power Plant, Exclusion Zone, «self-settlers», radiation doses, health.

Sign in / Sign up

Export Citation Format

Share Document