Chapter 5 Ionizing Radiation: Dose and Exposure—Measurements, Standards and Protection

2017 ◽  
pp. 139-163
Author(s):  
B H Brown
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Exposure Measurements

scholarly journals Effects of exposure to low-dose ionizing radiation on changing platelets: a prospective cohort study

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Ning Liu ◽  
Yang Peng ◽  
Xinguang Zhong ◽  
Zheng Ma ◽  
Suiping He ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Dose Response ◽  
Low Dose ◽  
Linear Trend ◽  
Hematological Parameters ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Spline Models ◽  
Cumulative Radiation Dose

Abstract Background Numerous studies have concentrated on high-dose radiation exposed accidentally or through therapy, and few involve low-dose occupational exposure, to investigate the correlation between low-dose ionizing radiation and changing hematological parameters among medical workers. Methods Using a prospective cohort study design, we collected health examination reports and personal dose monitoring data from medical workers and used Poisson regression and restricted cubic spline models to assess the correlation between changing hematological parameters and cumulative radiation dose and determine the dose-response relationship. Results We observed that changing platelet of 1265 medical workers followed up was statistically different among the cumulative dose groups (P = 0.010). Although the linear trend tested was not statistically significant (Ptrend = 0.258), the non-linear trend tested was statistically significant (Pnon-linear = 0.007). Overall, there was a correlation between changing platelets and cumulative radiation dose (a change of βa 0.008 × 109/L during biennially after adjusting for gender, age at baseline, service at baseline, occupation, medical level, and smoking habits; 95% confidence interval [CI] = 0.003,0.014 × 109/L). Moreover, we also found positive first and then negative dose-response relationships between cumulative radiation dose and changing platelets by restricted cubic spline models, while there were negative patterns of the baseline service not less than 10 years (− 0.015 × 109/L, 95% CI = − 0.024, − 0.007 × 109/L) and radiation nurses(− 0.033 × 109/L, 95% CI = − 0.049, − 0.016 × 109/L). Conclusion We concluded that although the exposure dose was below the limit, medical workers exposed to low-dose ionizing radiation for a short period of time might have increased first and then decreased platelets, and there was a dose-response relationship between the cumulative radiation dose and platelets changing.

Radiation exposure during the treatment of spinal deformities

2021 ◽  
pp. 1-7
Author(s):  
Jwalant S. Mehta ◽  
Kirsten Hodgson ◽  
Lu Yiping ◽  
James Swee Beng Kho ◽  
Ravindra Thimmaiah ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Effective Dose ◽  
Spinal Deformity ◽  
Background Radiation ◽  
Ct Scans ◽  
Intraoperative Fluoroscopy ◽  
The Difference ◽  
Risk Of Cancer ◽  
Surgical Group

Aims To benchmark the radiation dose to patients during the course of treatment for a spinal deformity. Methods Our radiation dose database identified 25,745 exposures of 6,017 children (under 18 years of age) and adults treated for a spinal deformity between 1 January 2008 and 31 December 2016. Patients were divided into surgical (974 patients) and non-surgical (5,043 patients) cohorts. We documented the number and doses of ionizing radiation imaging events (radiographs, CT scans, or intraoperative fluoroscopy) for each patient. All the doses for plain radiographs, CT scans, and intraoperative fluoroscopy were combined into a single effective dose by a medical physicist (milliSivert (mSv)). Results There were more ionizing radiation-based imaging events and higher radiation dose exposures in the surgical group than in the non-surgical group (p < 0.001). The difference in effective dose for children between the surgical and non-surgical groups was statistically significant, the surgical group being significantly higher (p < 0.001). This led to a higher estimated risk of cancer induction for the surgical group (1:222 surgical vs 1:1,418 non-surgical). However, the dose difference for adults was not statistically different between the surgical and non-surgical groups. In all cases the effective dose received by all cohorts was significantly higher than that from exposure to natural background radiation. Conclusion The treatment of spinal deformity is radiation-heavy. The dose exposure is several times higher when surgical treatment is undertaken. Clinicians should be aware of this and review their practices in order to reduce the radiation dose where possible.

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 Disinfection of Archived Material by Radiation Processing Technology Keeping the Material Integrity

2018 ◽  
Vol 33 (1-2) ◽  
pp. 1-4
Author(s):  
Md Kamruzzaman Pramanik ◽  
Abdul Bathen Miah ◽  
Md Khorshed Alam
Keyword(s):  
Tensile Strength ◽  
Radiation Dose ◽  
Ionizing Radiation ◽  
Bacterial Count ◽  
B Value ◽  
Total Bacterial Count ◽  
Elongation At Break ◽  
Colour Parameter ◽  
60Co Source ◽  
L Value

The aim of the study was to preserve paper-based archived material for a long period of time using ionizing radiation/nuclear technique. To conduct this research, old note-pad samples were selected as tentative archived material. Samples were prepared and irradiated at a series of radiation doses e.g. 0, 2.0, 4.0, 6.0, 8.0, 10.0 and 14.0 kGy at a dose rate of 12.8 kGy/h from panaromic Batch type 80 kCi 60Co source. After irradiation, different quality parameters such as microbiological (Total Viable Bacterial Count, Total Fungal Count), mechanical (Tensile Strength, Percent of Elongation at Break and Elastic Modulus) and color properties (L-value, a-value and b-value) of the samples were assessed to observe the immediate effect of ionizing radiation on these properties. Results showed that the total bacterial count of unirradiated (control) paper were 4.0X102 cfu/g and radiation dose of 2.0 kGy was enough to eliminate the microbial load completely. Among mechanical properties, tensile strength (TS) of unirradiated sample was 16.23 MPa and it was gradually increased as the dose increased and finally reached upto 18.99 MPa at a dose of 14 kGy causing the TS-change above significant level (p < 0.05). Though changes of percent of elongation at break (EB) due to irradiation was insignificant, elastic module (EM) increased as the radiation dose increased gradually. EM of non irradiated sample was 381.85N/m2 and it started changing significantly from 6.0 kGy and finally reaches upto 477.03 N/m2 at 14.0 kGy. Results showed that L-value of colour parameter changed very slightly though a and b-value changed significantly from 6.0 kGy. From these findings it can be inferred that a radiation dose of 4.0 kGy might be used to conserve the cultural heritage including valuable paper-based archived materials. Bangladesh J Microbiol, Volume 33, Number 1-2, June-Dec 2016, pp 1-4

scholarly journals An in vitro of radiation dose enhancement using gold nanorods and plasmonic photothermal therapy

2021 ◽  
Author(s):  
Daniel DiCenzo DiCenzo
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Gold Nanorods ◽  
Near Infrared ◽  
Infrared Light ◽  
Nuclear Localization Sequence ◽  
X Rays ◽  
Dose Enhancement ◽  
Near Infrared Light ◽  
Pc3 Cells

Gold nanoparticles (GNP) have been shown to highly absorb ionizing radiation compared to tissue. GNPs have also been shown to be high absorbers of non-ionizing radiation with a peak absorbance at a wavelength dependent on their shape and size. This study investigated radiation dose enhancement in PC3 cells when in the presence of gold nanorods (NR) and near infrared light (IR). The PC3 cells were incubated with either PEGylated NRs (PNR) or anti prostate stem cell antigen antibody with nuclear localization sequence peptide conjugated NRs (AbNR). They were exposed to near infrared light at a wavelength of 810 nm to achieve a temperature of 42 ºC to 43 ºC for 60 minutes. They were also exposed to 160 kVp x-rays. It was found that both targeted and non-targeted GNPs when exposed to radiation and near infrared light synergistically enhanced radiation dose. It was also found that AbNRs provide greater dose enhancement than PNRs.

Sign in / Sign up

Export Citation Format

Share Document