Radiation Dose and Somatic Risk from Computed Tomography

1987 ◽  
Vol 28 (4) ◽  
pp. 483-488 ◽  
Author(s):  
K. Faulkner ◽  
B. M. Moores
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Male Patient ◽  
Dose Distribution ◽  
Lithium Fluoride ◽  
Central Axis ◽  
Organ Doses ◽  
Ct Examination ◽  
Genetic Risks ◽  
Thermoluminescent Dosemeters

Lithium fluoride (LiF) thermoluminescent dosemeters (TLD) have been employed to measure the radiation dose distribution within a phantom and the central axis dose in air. Results are presented for seven (four EMI CT1010, one EMI CT5005, one EMI CT7070 and one Siemens DR2) different machines. Organ doses for four different computed tomography (CT) investigations (head, lung, liver and pelvis) have been estimated from previously published tables and the central axis dose in air in 3 CT units. These estimated organ doses were used in turn to deduce the somatic and genetic risks for the four types of CT examination. These calculations indicate that for an ‘average’ male patient undergoing a CT examination corresponding to the average conditions encountered, the total somatic risks are 3.15 10−4, 1.98 10−4, 2.31 10−4, and 1.38 10−4 for head, lung, liver and pelvis scans, respectively. The corresponding figures for female patients are 3.39 10−4, 3.95 10−4, 2.73 10−4, and 1.60 10−4. The risk from head scanning is approximately 250 times that of a dental pantomograph. Somatic and genetic risks will be approximately twice as high for contrast examinations.

Measurement of radiation dose distribution in a pond habitat by lithium fluoride dosimetry

1969 ◽  
Vol 47 (1) ◽  
pp. 17-20 ◽  
Author(s):  
J. E. Guthrie ◽  
A. G. Scott
Keyword(s):  
Radiation Dose ◽  
Dose Distribution ◽  
Lithium Fluoride ◽  
Gamma Dose ◽  
Thermoluminescent Dosimetry ◽  
Small Plastic ◽  
Chironomidae Larvae ◽  
Cesium 137

Thermoluminescent dosimetry has been used to measure the radiation dose accumulated by Chironomidae larvae inhabiting a 19-m diameter pond contaminated with cesium-137. Small plastic tubes filled with lithium fluoride powder were arranged in parallel rows along the pond bottom. The accumulated gamma dose was greatest at the pond margin.

scholarly journals Evaluation of the Effect of a Tracheal Stent on Radiation Dose Distribution via Micro-CT Imaging

2019 ◽  
Vol 18 ◽  
pp. 153303381984448
Author(s):  
Tao Lin ◽  
Xinye Ni ◽  
Liugang Gao ◽  
Jianfeng Sui ◽  
Kai Xie ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Dose Distribution ◽  
Photon Beam ◽  
Micro Computed Tomography ◽  
Computed Tomography Imaging ◽  
Tomography Imaging ◽  
Tracheal Stent ◽  
Exit Surface ◽  
Computed Tomography Images

Purpose: To study the effect of a metal tracheal stent on radiation dose distribution. Method: A metal tube bracket is placed in a self-made foam tube sleeve, and micro-computed tomography scanning is performed directly. The foam sleeve containing the metal bracket is placed in a nonuniform phantom for a routine computed tomography scan. The stents in conventional computed tomography images are replaced by the stents in micro-computed tomography images. Subsequently, 2 sets of computed tomography images are obtained and then imported to a radiotherapy treatment planning system. A single photon beam at 0° is designed in a field size of 10 cm × 10 cm, a photon beam of 6 MV, and a monitor unit of 200 MU. Monte Carlo algorithm is used to calculate the dose distribution and obtain the dose curve of the central axis of the field. The dose is verified with thermoluminescence dose tablets. Results: The micro-computed tomography images of the tracheal stent are clearer and less false-like than its conventional computed tomography images. The planned dose curves of the 2 groups are similar. In comparison with the images without any stents in place, the doses at the incident surface of the stent in the conventional computed tomography images and at the stent exit surface in the rear of the stent increase by 1.86% and 2.76%, respectively. In the micro-computed tomography images, the doses at the incident surface of the stent and at the exit surface behind the stent increase by 1.32% and 1.19%, respectively. Conventional computed tomography reveals a large deviation between the measured and calculated values. Conclusion: Tracheal stent based on micro-computed tomography imaging has a less effect on radiotherapy calculation than that based on conventional computed tomography imaging.

scholarly journals Occupational Radiation Dose, Especially for Eye Lens: Hp(3), in Medical Staff Members Involved in Computed Tomography Examinations

2021 ◽  
Vol 11 (10) ◽  
pp. 4448
Author(s):  
Minoru Osanai ◽  
Hidenori Sato ◽  
Kana Sato ◽  
Kohsei Kudo ◽  
Masahiro Hosoda ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Radiation Protection ◽  
Medical Staff ◽  
Shielding Effect ◽  
Eye Lens ◽  
Radiological Protection ◽  
Ct Examination ◽  
Radiation Dose Exposure ◽  
Occupational Radiation

Radiation dose management of medical staff has become increasingly important. Particularly, based on the statement by the International Commission on Radiological Protection (ICRP) in 2011, a new lower equivalent dose limit for the eye lens is being established in each country. Although many reports have discussed the occupational radiation dose in interventional radiology (IR), few studies have examined the dose during computed tomography (CT) examinations. This study investigated the radiation dose exposure to medical staff present in the CT room during irradiation, with particular focus on the exposure to eye lens. The radiation dose exposure to those who assist patients during head, chest and upper abdomen CT examination was measured in a phantom study. The radiation dose exposure with scattered radiation was never negligible (i.e., high); Hp(3) was the highest in head CT examination, at 0.44 mSv per examination. Furthermore, the shielding effect of radiation protection glasses was large, and radiation protection glasses are useful tools for the medical staff who are involved in CT examinations. The justification and optimisation should be carefully considered in assistant actions.

THE IMPACT OF OBESITY ON ABDOMINAL CT RADIATION DOSE AND IMAGE QUALITY

2018 ◽  
Vol 185 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Abdulaziz A Qurashi ◽  
Louise A Rainford ◽  
Khalid M Alshamrani ◽  
Shane J Foley
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Organ Dose ◽  
Oxide Semiconductor ◽  
Obese Patients ◽  
Dose Length Product ◽  
Organ Doses ◽  
The Impact

Abstract The aim of this study was to evaluate how iterative reconstruction can compensate for the noise increase in low radiation dose abdominal computed tomography (CT) technique for large size patients and the general impact of obesity on abdominal organ doses and image quality in CT. An anthropomorphic phantom layered with either none or a single layer of 3-cm- thick circumferential animal fat packs to simulate obese patients was imaged using a 128MDCT scanner. Abdominal protocols (n = 12) were applied using automatic tube current modulation (ATCM) with various quality reference mAs (150, 200, 250 and 300). kVs of 100, 120 and 140 were used for each mAs selection. Metal oxide semiconductor field effect transistor dosimeters (MOSFET) measured internal organ dose. All images produced were reconstructed with filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE) (3, 4 and 5) and objective noise was measured within three regions of interest at the level of L4–L5. Organ doses varied from 0.12 to 41.9 mGy, the spleen received the highest doses for both phantom sizes. Compared to the phantom simulating average size, the obese phantom was associated with up to twofold increase in delivered mAs, dose length product (DLP) and computed tomography dose index (CTDIvol) for the matched mAs selection (p < 0.05). However, organ dose increased by 50% only. The use of 100 kV resulted in a 40% lower dose (p < 0.05) compared to 120 kV and the associated noise increase was improved by SAFIRE (5) use, which resulted in 60% noise reduction compared to FBP (p < 0.05). When combined with iterative reconstruction, low kV is feasible for obese patients to optimise radiation dose and maintain objective image quality.

DEVELOPMENT OF A SPECIALISED TAPE MEASURE TO ESTIMATE THE SIZE-SPECIFIC DOSE ESTIMATE

2020 ◽  
Vol 191 (3) ◽  
pp. 369-375
Author(s):  
Tomokazu Shohji ◽  
Kazuki Kuriyama ◽  
Nobutaka Yanano ◽  
Yo Katoh
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Radiation Exposure ◽  
Ct Images ◽  
Ct Scans ◽  
Dose Estimate ◽  
Ct Examination ◽  
Tape Measure ◽  
Wide Range ◽  
Standard Deviations

Abstract The risk in computed tomography (CT) examinations is radiation exposure. We aimed to develop a specialised tape measure for determining the size-specific dose estimate (SSDE) for patients undergoing CT scans. The scanning parameters used were those of the abdominal protocol in our institute. With this method, the SSDE220 and standard deviations obtained from CT images for the liver, pelvic and lung areas, corresponded closely to the SSDEtape and standard deviations obtained using the tape measure. We thus devised a new idea that allows the estimation of the SSDE220 using a specialised tape measure before the CT examination, allowing for an informed explanation of the radiation dose to the patient. Although the tape measure developed in this study is specific to one particular CT instrument, the method could be adapted to a wide range of radiography applications.

scholarly journals Do you know the radiation dose your patients receive from your CT scanner?

2001 ◽  
Vol 5 (2) ◽  
pp. 30-34
Author(s):  
Chris Welman ◽  
Savvas Andronikou ◽  
Ebrahim Kader
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Ct Scanner ◽  
Ct Examination ◽  
Probability Of Cancer ◽  
Medical Examinations ◽  
Dose Reductions

The number of computed tomography (CT) examinations and new indications for CT are increasing in frequency worldwide. While CT makes up only 4% of medical examinations, it might contribute as much as 40% of the total collective radiation dose to the population. Radiologists and referring clinicians should make sure that the CT examination is indicated. Doses can often approach or exceed levels known to increase the probability of cancer. This is especially relevant in children where dose reductions of up to 80% can be obtained by adjusting the exposure factors. The most important factors are decreased milliampere seconds (mAs) and increased pitch.

scholarly journals Low Radiation Dose Implications in Obese Abdominal Computed Tomography Imaging

2021 ◽  
Vol 11 (6) ◽  
pp. 2456
Author(s):  
Abdulaziz A. Qurashi ◽  
Louise A. Rainford ◽  
Fahad H. Alhazmi ◽  
Khalid M. Alshamrani ◽  
Abdelmoneim Sulieman ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Noise Reduction ◽  
Effective Dose ◽  
Iterative Reconstruction ◽  
Multidetector Ct ◽  
Obese Patients ◽  
Organ Doses ◽  
Low Radiation Dose ◽  
Abdominal Computed Tomography

The aim of this study was to evaluate the implications of low radiation dose in abdominal computed tomography (CT) when combined with noise reduction filters and to see if this approach can overcome the challenges that arise while scanning obese patients. Anthropomorphic phantoms layered with and without 3-cm-thick circumferential animal fat packs to simulate different sized patients were scanned using a 128-slice multidetector CT (MDCT) scanner. Abdominal protocols (n = 12) were applied using various tube currents (150, 200, 250, and 300 mA) and tube voltages (100, 120, and 140 kVp). MOSFET dosimeters measured the internal organ dose. All images were reconstructed with filtered back projection (FBP) and different iterative reconstruction (IR) strengths (SAFIRE 3, SAFIRE 4, and SAFIRE 5) techniques and objective noise was measured within three regions of interests (ROIs) at the level of L4–L5. Organ doses varied from 0.34–56.2 mGy; the colon received the highest doses for both phantom sizes. Compared to the normal-weighted phantom, the obese phantom was associated with an approximately 20% decrease in effective dose. The 100 kVp procedure resulted in a 40% lower effective dose (p < 0.05) compared to at 120 kVp and the associated noise increase was improved by increasing the IR (5) use, which resulted in a 60% noise reduction compared to when using FBP (p < 0.05). When combined with iterative reconstruction, the low-kVp approach is feasible for obese patients in order to optimize radiation dose and maintain objective image quality.

scholarly journals Analysis of Organ Doses from Computed Tomography (CT) Examination by the Radiation Transport Calculation to Develop the Dosimetry System, WAZA-ARI

2011 ◽  
Vol 1 (0) ◽  
pp. 517-520 ◽  
Author(s):  
Fumiaki TAKAHASHI ◽  
Akira ENDO ◽  
Kaoru SATO ◽  
Takayuki HASEGAWA ◽  
Yasushi KATSUNUMA ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Transport ◽  
Organ Doses ◽  
Ct Examination ◽  
Transport Calculation ◽  
Dosimetry System

scholarly journals Reducing fetal radiation dose in computed tomography for pregnant patients: A literature review

2021 ◽  
Vol 2 (4) ◽  
pp. 35-43
Author(s):  
Hamid Ghaznavi ◽  
Keyword(s):  
Computed Tomography ◽  
Pulmonary Embolism ◽  
Radiation Dose ◽  
Renal Stones ◽  
Gestation Period ◽  
Ct Examination ◽  
Golden Standard ◽  
Ionization Radiation ◽  
Radiation Beams ◽  
Fetal Dose

To diagnose diseases during gestation period including renal stones, appendicitis, and pulmonary embolism in pregnant patients, computed tomography (CT) can be a golden standard. Due to CT examination, the fetus is prone to receiving a considerable dose which is the result of direct or scattered (external and internal scattered radiation) beams. The effects of ionization radiation on fetus include mutagenesis and carcinogenesis, therefore, it is essential to reduce fetus dose for pregnant patients who undergo CT examination during gestation period. This article aims to review approaches that are effective in reducing fetal dose in pregnant patients.

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