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

• Journal of radiological science and technology
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• v.42 no.2
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• pp.105-111
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• 2019

A medical personnel could be placed beside a patient together in CT room to do Ambu-bag for a seriously ill patients or emergency patient. At this time, the medical personnel can be exposed indirect radiation unnecessarily. In this case, it is necessary to recognize indirect radiation dose levels and methods to reduce them using actual clinical CT protocols such as Chest, Abdomen, and Brain CT. We researched surface radiation dose with or without radiation protectors such as apron and goggles according to different distances far from gantry using two different CT scanners (Fixed MDCT and mobile CT). As a result, for Chest, Abdomen, and Brain CT with Fixed MDCT, indirect radiation dose on thorax portion were 0.047, 0.089, 0.034 mSv without apron. Also, those with apron were 0.007, 0.012, 0.006 mSv. In case of mobile CT, it was 0.014 mSv without apron and 0.005 mSv with apron. By using protectors and increasing the distance, we could reduce it to 97%. Systematic management is necessary based on the measured data in order to minimize radiation damage due to indirect exposure dose.

• Journal of radiological science and technology
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• v.25 no.2
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• pp.35-38
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• 2002

Recently, They are usually recording the patient information on the Hospital Information System. In the department of Radiology, For the purpose of assuming patient exposed dose, Authors contrived the mathematical calculation model by use of x-ray out put data on the Excel program, if they in put the exposure factors (kVp, mAs, thickness), the program could automatically calculate the patient Skin dose. The assuming data by three dimensional equation has average errors within ${\pm}5%$, there for We could make good use of clinical field in department of radiology.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.895-908
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• 2018

As modern science is developed and advanced, examination and number of times using radiation are increasing daily. General diagnostic X-ray generator is installed on stationary form, But X-ray generator was developed because patient who is in the intensive care unit, operation room, emergency room can not move to general x-ray room. What we examine patient by x-ray generator is certainly necessary, So patient exposure is inevitable. but reducing radiation exposure is highly important matter about radiation technology, guardian, patient in the same hospital room, nurse etc. For this reason, rule regarding safety control of diagnostic x-ray generator revised for radiation worker, patient and protector proclaim that mobile diagnostic x-ray shield must placed in case of examine different location excluding operation room, emergency room, intensive care unit. But, radiogical technologist is having a lot of difficulties to examine with mobile x-ray generator, diagnostic x-ray shield partition, image plate and lead apron. So, when we use x-ray generator, we manufacture shield tools can be attached to the mobile x-ray generator On behalf of x-ray shield partition and conduct analysis and in comparison to part of body and distribution of dose rate and find way to reduce radiation exposure through distribution of dose rate of patient within the radiogical technologist, medical team. Mobile x-ray generator aimed at SHIMADZU inc. R-20, We manufactured equipment for shielding x-ray scattered x-ray by installing shielding wall from side to side based on support beam on the mobile x-ray generator. Shielding wall when moving can be folded and designed to expand when examine. Experiment measured five times in each by an angle for dose rate of eyes, thyroid, breast, abdomen and gonad on exposure condition of upper and lower extremity, chest, abdomen which is examined many times by mobile x-ray generator. We used dosimeter RSM-100 made by IJRAD and measured a horizontal dose rate by body part. The result of an experiment, shielding decreasing rate of the front and the rear showed 77 ~ 98.7%. Therefore using self-production shielding wall reduce scattered x-ray occurrence rate and confirm can decrease exposure dose consequently. Therefore, through this study, reduction result which is used shielding wall of self-production will be a role of shielding optimization and it could be answer about reduction of medical exposure recommended by ICRP 103.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.903-909
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• 2023

The purpose of this study is to compare and analyze the effect of changes in the patient's central position on the exposure dose and image quality of surrounding organs during a chest lateral examination using an Auto Exposure Control(AEC). The experiment was conducted on a human body phantom. A needle was attached to the lower part of the center of the coronal plane of the phantom, and a lead ruler was attached to the lower part of the detector so that the 50 cm point was located at the lower center of the AEC ion chamber. The exposure conditions were 125 kVp, 320 mA, the distance between the source and the image receptor was 180 cm, and the exposure field size was 14 × 17 inches. Only one AEC ion chamber was used at the bottom center, and the density was set to '0' and sensitivity to 'Middle', and the central X-ray was incident vertically toward the 6th thoracic vertebra. With AEC mode applied, the 50 cm point of the needle and lead ruler were aligned and the phantom was moved 5 cm toward the stomach (F5) and 5 cm toward the back (B5), and the dose factor was analyzed by measuring ESD. The ESD of the thyroid gland according to the change in patient center position was 232.60±2.20 μGy for Center, 231.22±1.53 μGy for F5, and 184.37±1.19 μGy for B5, and the ESD of the breast was 288.54±3.03 μGy for Center, F5 was 260.97±1.93 μGy, B5 was 229.80±1.62 μGy, and the ESD of the center of the lung was 337.02±3.25 μGy for Center, F5 was 336.09±2.29 μGy, and B5 was 261.76±1.68 μGy. As a result of comparing the average values of dose factors between each group, the difference in average values was statistically significant (p<0.01), and each group appeared to be independent. As a result of the study, there was no significant difference in the dose to the thyroid, breast, and center of the lung according to the change in the patient's central position, except for the breast (10%) when the patient moved forward about 5 cm. However, movement of about 5 cm posteriorly resulted in an average dose reduction of 23.7%. Additionally, when the patient's central position was moved to the rear, image quality deteriorated.

• Imaging Science in Dentistry
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• v.42 no.4
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• pp.207-212
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• 2012

Purpose: This study was performed to determine the relative frequency of positioning errors, to identify those errors directly responsible for diagnostically inadequate images, and to assess the quality of panoramic radiographs in a sample of records collected from a dental college. Materials and Methods: This study consisted of 1,782 panoramic radiographs obtained from the Department of Oral and Maxillofacial Radiology. The positioning errors of the radiographs were assessed and categorized into nine groups: the chin tipped high, chin tipped low, a slumped position, the patient positioned forward, the patient positioned backward, failure to position the tongue against the palate, patient movement during exposure, the head tilted, and the head turned to one side. The quality of the radiographs was further judged as being 'excellent', 'diagnostically acceptable', or 'unacceptable'. Results: Out of 1,782 radiographs, 196 (11%) were error free and 1,586 (89%) were present with positioning errors. The most common error observed was the failure to position the tongue against the palate (55.7%) and the least commonly experienced error was patient movement during exposure (1.6%). Only 11% of the radiographs were excellent, 64.1% were diagnostically acceptable, and 24.9% were unacceptable. Conclusion: The positioning errors found on panoramic radiographs were relatively common in our study. The quality of panoramic radiographs could be improved by careful attention to patient positioning.

• Korean Journal of Digital Imaging in Medicine
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• v.17 no.1
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• pp.13-18
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• 2015

Purpose : Skip the repetitive HRCT axial scan in order to reduce the exposure of patients during chest HRCT scan, Helical Scan Data into a reconstructed image, and exposure of the patient change and visually evaluate the usefulness of the HRCT images. Materials and method : Patients were enrolled in the survey are 50 people who underwent chest CT scans of patients who presented to the hospital from January 2015 to March 2015. 50 people surveyed 22 people men and 28 people women people showed an average distribution of 30 to 80 years age was 48 years. 50 patients to Somatom Sensation 64 ch (Siemens) model with 120 kVp tube voltage to a reference mAs tube current to mAs (Care dose, Siemens) as a whole, including the lungs and the chest CT scan was performed. Scan upon each patient CARE dose 4D (Automatic exposure control, Siemens Medical Solution Erlangen, Germany) was to maintain the proper radiation dose scan every cross-section through a device that automatically adjusts the tube current of. CT scan is the rotation time of the Tube slice collimation, slice width 0.6 mm, pitch factor was made under the terms of 1.4. CT scan obtained after the raw data (raw data) to the upper surface of the axial images and coronal images for each slice thickness 1 mm, 5 mm intervals in the high spatial frequency calculation method (hight spatial resolution algorithm, B60 sharp) was the use of the lung window center -500 HU, windows were reconstructed into images in the interval -1000 HU to see. Result : 1. Measure the total value of DLP 50 patients who proceed to chest CT group A (Helical Scan after scan performed with HRCT) and group B (Helical Scan after the HR image reconstruction to the original data) compared with the group divided, analysis As a result of the age, but show little difference for each age group it had a decreased average dose of about 9%. 2. A Radiation read the results of the two Radiologist and a doctor upper lobe and middle lobe of the lung takes effect the visual evaluation is not a big difference between the two images both, depending on the age of the patient, especially if the blood vessels of the lower lobe (A: 3.4, B: 4.6) and bronchi(A: 3.8, B4.7) image shake caused by breathing in anxiety (blurring lead) to the original data (raw data) showed that the reconstructed image is been more useful in diagnostic terms. Conclusion : Scan was confirmed a continuous, rapid motion video to get Helical scan is much lower lobe lung reduction in visual blurring, Helical scan data to not repeat the examination by obtaining HRCT images reorganization reduced the exposure of the patient.

• Journal of radiological science and technology
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• v.45 no.4
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• pp.347-353
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• 2022

In this study, the radiation dose rate was measured by time and distance and evaluated whether radiation dose rate was suitable for domestic and international discharge criteria. In addition, the radiation dose emitted from the patient was measured with a glass dosimeter to evaluate the exposure dose if the caregiver stays in the isolated ward by placing a humanoid phantom instead of the caregiver at a distance of 1 m from the patient, on the second day of treatment. After 23 hours of isolation, the radiation dose rates at a distance of 1 m were 20.54 ± 6.21 µSv/h at 2.96 GBq administration and 27.94 ± 12.33 µSv/h at 3.70 GBq administration. The radiation dose rates at a distance of 1 m were 25.90 ± 2.21 µSv/h when 2.96 GBq was administered and 34.22 ± 10.06 µSv/h when 3.70 GBq was administered after 18 hours of isolation. However, if the isolation period is short may cause unnecessary radiation exposure to the third person. The reading of the attached dosimeter from the morning of the second day of treatment until removal was 0.01 to 0.95 mSv, which is a surface dose determined by the International Commission on Radiation Units and Measurements. And the depth dose was 0.01 to 0.99 mSv. On the second day of treatment, even if the patient caregivers stayed in the isolation ward, the exposure dose of the patient family did not exceed the effective dose limit of 5 mSv recommended by the ICRP and NCRP.

• Journal of radiological science and technology
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• v.38 no.2
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• pp.101-106
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• 2015

Recently, There has been a growing interests in exposure dose to the patient who take a examination using radiation. The radiological technologists should be concerned about the exposure dose to patients and make an efforts to reduce the patient dose without decreasing the image quality. In the case of foreign, the exposure dose of general X-ray examination have been managed by standard value of exposure dose using dose area product (DAP) and entrance surface dose (ESD) dosimeter. This study is to compare DAP and ESD in skull anterior posterior (AP), chest posterior anterior (PA), and abdomen AP projections of phantom by using DAP and ESD dosimeter. In the results, there were no differences between DAP and ESD dosimeter.

• The Journal of the Korea Contents Association
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• v.14 no.3
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• pp.337-345
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• 2014

The purpose of this study is to evaluate exposure dose and absorbability according to differences in the content of iodine in contrast media used in interventional procedure and angiography. There were 7 levels of iodine content as 240, 270, 300, 320, 350, 370, and 400 I $mg/m{\ell}$. The higher iodine content was, the more elevated exposure dose and absorbability were. The output dose was about 8.5% from iodine content with 350I $mg/m{\ell}$ higher than that with 270 I $mg/m{\ell}$ in TACE. These results mean that contrast media can have an effect on patient's exposure dose and high iodine content contrast media results in elevation of patient's exposure dose.