• Journal of Radiation Industry
• /
• v.12 no.4
• /
• pp.365-372
• /
• 2018

The use of CT examinations is increasing rapidly and radiation dose from CT examinations is much higher than other diagnostic radiography examinations including general radiography and mammography. DRLs used to optimize the radiation dose of patients by diagnostic radiology in each country. The objective of this study was to investigate and to analyze the status of DRLs from CT examinations in domestic and other countries. In other countries, DRLs were set for each age group and each examination considering the medical situation of each country. In Korea, DRLs were set for adults and children in 2017. For adults, DRLs were set for 13 examinations. Reported DLP values were 1119, 297, $472mGy{\cdot}cm$ for head, chest and abdomen pelvis examination, respectively. For children, DRLs were set for head examinations. Reported DLP values were 298 (0~1 years), 404 (2~5 years), 494 (6~10 years), 1,088 (11~15 years) $mGy{\cdot}cm$. DRLs of Korea were similar to other countries for head examinations. For chest examinations and abdomen pelvis examinations were relatively lower than other countries. As a major reason for relatively low radiation dose, it is considered to contribute the activity and management of medical radiation safety at national level.

• Journal of Radiation Protection and Research
• /
• v.48 no.1
• /
• pp.9-14
• /
• 2023

Background: The detectors of both computed radiography (CR) and direct digital radiography (DR) have a wide dynamic range that could tolerate high values of exposure factors without an adverse effect on image quality. Therefore, this study aims to assess patient radiation dose and proposes institutional diagnostic reference levels (DRLs) for two teaching hospitals in Ghana. Materials and Methods: CR and DR systems were utilized in this study from two teaching hospitals. The CR system was manufactured by Philips Medical Systems DMC GmbH, while the DR system was manufactured by General Electric. The entrance skin doses (ESDs) were calculated using the standard equation and the tube output measurements. Free-in-air kerma (µGy) was measured using a calibrated radiation dosimeter. The proposed institutional DRLs were estimated using 75^th percentiles values of the estimated ESDs for nine radiographic projections. Results and Discussion: The calculated DRLs were 0.4, 1.6, 3.4, 0.5, 0.4, 1.1, 1.0, 1.2, and 1.7 mGy for chest posteroanterior (PA), lumbar spine anteroposterior (AP), lumbar spine lateral (LAT), cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively in CR system. In the DR system, the values were 0.3, 1.6, 3.1, 0.4, 0.3, 0.7, 0.6, 0.9, and 1.3 for chest PA, lumbar spine AP, lumbar spine LAT, cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively. Conclusion: Institutional DRLs in nine radiographic projections have been proposed for two teaching hospitals in Ghana for the first time. The proposed DRLs will serve as baseline data for establishing local DRLs in the hospitals and will be a valuable tool in optimizing patient doses.

• Korean Journal of Radiology
• /
• v.22 no.7
• /
• pp.1172-1184
• /
• 2021

Objective: The purposes of this study were to analyze the radiation doses for pediatric abdominopelvic and chest CT examinations from university hospitals in Korea and to establish the local diagnostic reference levels (DRLs) based on the body weight and size. Materials and Methods: At seven university hospitals in Korea, 2494 CT examinations of patients aged 15 years or younger (1625 abdominopelvic and 869 chest CT examinations) between January and December 2017 were analyzed in this study. CT scans were transferred to commercial automated dose management software for the analysis after being de-identified. DRLs were calculated after grouping the patients according to the body weight and effective diameter. DRLs were set at the 75th percentile of the distribution of each institution's typical values. Results: For body weights of 5, 15, 30, 50, and 80 kg, DRLs (volume CT dose index [CTDI_vol]) were 1.4, 2.2, 2.7, 4.0, and 4.7 mGy, respectively, for abdominopelvic CT and 1.2, 1.5, 2.3, 3.7, and 5.8 mGy, respectively, for chest CT. For effective diameters of < 13 cm, 14-16 cm, 17-20 cm, 21-24 cm, and > 24 cm, DRLs (size-specific dose estimates [SSDE]) were 4.1, 5.0, 5.7, 7.1, and 7.2 mGy, respectively, for abdominopelvic CT and 2.8, 4.6, 4.3, 5.3, and 7.5 mGy, respectively, for chest CT. SSDE was greater than CTDI_vol in all age groups. Overall, the local DRL was lower than DRLs in previously conducted dose surveys and other countries. Conclusion: Our study set local DRLs in pediatric abdominopelvic and chest CT examinations for the body weight and size. Further research involving more facilities and CT examinations is required to develop national DRLs and update the current DRLs.

• Journal of radiological science and technology
• /
• v.46 no.2
• /
• pp.123-129
• /
• 2023

Interventional cardiology procedures can involve relatively high radiation doses compared to conventional radiography. During CAG, CAG + PCI and PCI the same area is exposed to radiation for a long period. In this study, radiation exposure data of 421 examinations in Gyeongsang area were collected, and the DRLs and ADs in actual medical practice for three types of interventional cardiology procedures in Korea were established. In CAG 286 case, 75th percentile DRLs and ADs of the total DAP were 55.89 Gy·cm² and 37.47 Gy·cm² , respectively. In CAG + PCI 92 case, those values were 222.84 Gy·cm² and 117.51 Gy·cm² respectively. In PCI 43 case, those values were 198.73 Gy·cm² and 120.13 Gy·cm² respectively. In this study, for the first time, the diagnostic reference level of interventional cardiology procedures in Gyeongsang area were established. Using the diagnostic reference level of interventional cardiology procedures derived from this study, it will help to identify and improve the level of exposure dose in the region and country.

• Progress in Medical Physics
• /
• v.30 no.4
• /
• pp.75-88
• /
• 2019

Diagnostic reference level (DRL) is employed to optimize the radiation doses of patients. The objective of this study is to review the DRLs for interventional procedures in Korea and abroad. Literature review was performed to investigate radiation dose index and measurement methodology commonly used in DRL determination. Dose area product (DAP) and fluoroscopy time within each major procedure category were systematically abstracted and analyzed. A wide variation was found in the radiation dose. The DAP values and fluoroscopy times ranged 0.01-3,081 Gy·㎠ and 2-16,878 seconds for all the interventional procedures, 8.5-1,679 Gy·㎠ and 32-5,775 seconds for the transcatheter arterial chemoembolization (TACE), and 0.1-686 Gy·㎠ and 16-6,636 seconds for the transfemoral cerebral angiography (TFCA), respectively. The DRL values of the DAP and fluoroscopy time were 238 Gy·㎠ and 1,224 seconds for the TACE and 189 Gy·㎠ and 686 seconds for the TFCA, respectively. Generally, the DRLs of Korea were lower than those of other developed countries, except for the percutaneous transluminal angioplasty with stent in arteries of the lower extremity (LE PTA and stent), aneurysm coil embolization, and Hickman insertion procedures. The wide variation in the radiation doses of the different procedures suggests that more attention must be paid to reduce unnecessary radiation exposure from medical imaging. Furthermore, periodic nationwide survey of medical radiation exposures is necessary to optimize the patient dose for radiation protection, which will ultimately contribute to patient dose reduction and radiological safety.

• Imaging Science in Dentistry
• /
• v.42 no.4
• /
• pp.237-242
• /
• 2012

Purpose: The objectives of this study were to survey the radiographic exposure parameters, to measure the patient doses for intraoral dental radiography nationwide, and thus to establish the diagnostic reference levels (DRLs) in intraoral dental X-ray examination in Korea. Materials and Methods: One hundred two intraoral dental radiographic machines from all regions of South Korea were selected for this study. Radiographic exposure parameters, size of hospital, type of image receptor system, installation duration of machine, and type of dental X-ray machine were documented. Patient entrance doses (PED) and dose-area products (DAP) were measured three times at the end of the exit cone of the X-ray unit with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for adult mandibular molar intraoral dental radiography, and corrections were made for room temperature and pressure. Measured PED and DAP were averaged and compared according to the size of hospital, type of image receptor system, installation duration, and type of dental X-ray machine. Results: The mean exposure parameters were 62.6 kVp, 7.9 mA, and 0.5 second for adult mandibular molar intraoral dental radiography. The mean patient dose was 2.11 mGy (PED) and 59.4 $mGycm^2$ (DAP) and the third quartile one 3.07 mGy (PED) and 87.4 $mGycm^2$ (DAP). Doses at university dental hospitals were lower than those at dental clinics (p<0.05). Doses of digital radiography (DR) type were lower than those of film-based type (p<0.05). Conclusion: We recommend 3.1 mGy (PED), 87.4 $mGycm^2$ (DAP) as the DRLs in adult mandibular molar intraoral dental radiography in Korea.

• The Journal of the Korean dental association
• /
• v.55 no.8
• /
• pp.516-526
• /
• 2017

Objective: To suggest diagnostic reference levels (DRLs) for dental panoramic radiography in adults and children through the nationwide survey in Korea. Materials and Methods: Two hundred twelve dental institutions on a national basis were visited. The radiographic examination protocols were surveyed and their patient doses at the clinical exposure setting for adult and children (5- and 10-year old) were measured at 244 panoramic radiographic equipment. The measured DAP were analyzed and compared according to age group, the size of hospital, the type of radiographic system, the installation duration of equipment. Results: The mean exposure parameters were 70.1 kV, 9.2 mA, 14.4 second for adult and 66.6 kV, 7.9 mA, 13.8 second for 10-year old child and 65.5 kV, 7.3 mA, 13.7 second for 5-year old child. The mean and third quartile patient DAPs were $138.3mGy\;cm^2$ and $151.0mGy\;cm^2$ for adult, $99.5mGy\;cm^2$ and $104.8mGy\;cm^2$ for 10-year old child and $89.5mGy\;cm^2$ and $95.5mGy\;cm^2$ for 5-year old child. The mean patient dose at the university dental hospital was lower than that at the dental clinic (p<0.05). The mean patient dose of direct digital radiography type was higher than that of film-based type. However, the difference did not show statistically significance. Conclusion: DRLs for dental panoramic radiography in adult, 10- and 5-year old child were suggested to be $151mGy\;cm^2$, $105mGy\;cm^2$, and $96mGy\;cm^2$ in Korea based on this nationwide survey.

• Journal of radiological science and technology
• /
• v.45 no.5
• /
• pp.407-412
• /
• 2022

Cerebral aneurysm coil embolization has the advantages of accurate, low patient burden, and fast recovery time, but efforts are needed to reduce dose due to the burden of exposure radiation dose during interventional procedures. In this study, the area dose product(DAP/Gy·cm²) and fluoro time(min) according to the size of the aneurysm and the location of aneurysm were investigated according to insurance recognition regulations aneurysm classification cerebral aneurysm coil embolization. According to the research method, classification according to the size and location of the aneurysm is first, the size of the aneurysm is divided into less than 4mm, more than 4mm to less than 8mm, and more than 8mm, and second, the dose to the area based on the location site (DAP/Gy·cm²) and fluoro time(min) based on the location site were observed. As a result, the location of the cerebral aneurysm procedure was found to be the Paraclinoid site. During cerebral aneurysm coil embolization, the area dose was 107 Gy·cm² and fluoro time was 47.41 minutes, showing lower results than domestic studies, and when comparing the area dose product with foreign studies, the area dose product results were similar to that of Turkey and Saudi Arabia. It is expected that it can be used as an objective analysis indicator to establish diagnostic reference levels (DRLs) and patient radiation defense guidelines according to the size of cerebral aneurysm and location of cerebral aneurysm procedures during interventional procedures.

• Journal of radiological science and technology
• /
• v.33 no.4
• /
• pp.327-334
• /
• 2010

Exposure during childhood results in higher risk for certain detrimental cancers than exposure during adulthood. We measured entrance skin dose (ESD) under 7-year children undergoing chest imaging and compared the relationship between ESD and age, height, weight, chest thickness. Though it is important to measure chest thickness for setting up the exposure condition of chest examination, it is difficult to measure chest thickness of children. We set up exposure parameters according to age because chest thickness of children has correlation with age. In the exposure parameters, for chest A-P examination under 2 year-children, tube voltage (kVp) in hospital A was higher than that in hospital B while tube current (mAs) was higher in hospital B, thus the ESD values were about 1.7 times higher in hospital B. However, for chest P-A examination over 4 year-children, the tube voltage was 7 kVp higher in hospital B, the tube current were same in all two systems, and focus to image receptor distance (FID) in hospital B (180 cm) was longer than that in hospital A (130 cm), thus the ESD values were 1.4 times higher in hospital A. For same ages, the ESD values for chest A-P examinations were higher than those for chest P-A examinations. Comparing ESD according to age, ESD values were $154{\mu}Gy$, $194{\mu}Gy$ and $138{\mu}Gy$ for children under 1 year, 1 to under 4 years and 4 to under 7 years of age, respectively. These values were lower than reference level ($200{\mu}Gy$) recommended in JART (japan association of radiological technologists), however these were higher than reference values recommended by EC (european commission), NRPB (national radiological protection board) and NIFDS (national institute of food & drug safety evaluation). In conclusion, the values of ESD were affected by exposure parameters from radiographer's past experience more than x-ray system. ESD values for older children were not always higher than those for younger children. Therefore we need to establish our own DRLs (diagnostic reference levels) according to age of the children in order to optimize pediatric patient protection.