• Journal of the Korean Society of Radiology
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• v.14 no.1
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• pp.23-29
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• 2020

The standard uptake values (SUVs) strongly depend on positron emission tomographs (PETs) and image reconstruction methods. Various image reconstruction algorithms in GE Discovery MIDR (DMIDR) and Discovery Ste (DSte) installed at Department of Nuclear Medicine, Seoul Samsung Medical Center were applied to measure the SUVs in an anthropomorphic torso phantom. The measured SUVs in the heart, liver, and background were compared to the actual SUVs. Applied image reconstruction algorithms were VPFX-S (TOF+PSF), QCFX-S-350 (Q.Clear+TOF+PSF), QCFX-S-50, VPHD-S (OSEM+PSF) for DMIDR, and VUE Point (OSEM) and FORE-FBP for DSte. To reduce the radiation exposure to radiation technologists, only the small amount of radiation source ¹⁸F-FDG was mixed with the distilled water: 2.28 MBq in the 52.5 ml heart, 20.3 MBq in the 1,290 ml liver and 45.7 MBq for the 9,590 ml in the background region. SUV values in the heart with the algorithms of VPFX-S, QCFX-S-350, QCFX-S-50, VPHD-S, VUE Point, and FOR-FBP were 27.1, 28.0, 27.1, 26.5, 8.0, and 7.4 with the expected SUV of 5.9, and in the background 4.2, 4.1, 4.2, 4.1, 1.1, and 1.2 with the expected SUV of 0.8, respectively. Although the SUVs in each region were different for the six reconstruction algorithms in two PET/CTs, the SUV ratios between heart and background were found to be relatively consistent; 6.5, 6.8, 6.5, 6.5, 7.3, and 6.2 for the six reconstruction algorithms with the expected ratio of 7.8, respectively. Mean SNRs (Signal to Noise Ratios) in the heart were 8.3, 12.8, 8.3, 8.4, 17.2, and 16.6, respectively. In conclusion, the performance of PETs may be checked by using with the SUV ratios between two regions and a relatively small amount of radioactivity.

• Korean Journal of Digital Imaging in Medicine
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• v.15 no.2
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• pp.31-37
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• 2013

Incident X-ray angles of weight bearing foot AP radiography which differ in each medical institution were compared. Optimal angles were derived from the study and suggested as basic data for clinical application. 19 patients with no abnormality on right foot took part in the study from June 2013 to July 2013. Weight bearing foot AP radiography in the correct position was examined with the incident X-ray angles of $10^{\circ}$, $15^{\circ}$, $20^{\circ}$, $25^{\circ}$, $30^{\circ}$, and $35^{\circ}$. All the images were evaluated subjectively by 5 radiological technologists of over 15 year work experience using Likert scale as 1 for 'very poor', 2 for 'poor', 3 for 'fair', 4 for 'good', 5 for 'very good', 6 for 'excellent', and analyzed with ANOVA and Scheffe. Image quality was the most optimal at $20^{\circ}$ as 4.53, and relatively good at $25^{\circ}$ as 4.38 and at $30^{\circ}$ as 4.18. $35^{\circ}$ and $10^{\circ}$ were relatively poor. The average points of 6 groups indicated statistically significant difference (p<.01). In the post-mortem, 3 subgroups showed no statistically significant difference, and the average point of the groups of $20^{\circ}$, $25^{\circ}$, $30^{\circ}$was evaluated relatively higher than the other 2 groups. An optimal incident X-ray angle within the range from $20^{\circ}$ to $30^{\circ}$ for weight bearing foot AP radiography could make it possible to obtain the image of high diagnostic value and would be useful for clinical application in the future.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.667-674
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• 2019

Because examination with technegas produces images through simple diffusion accumulation, the examination room can become contaminated after scan. Therefore, radiation workers and patients awaiting examination will be affected by internal exposure from technegas inhalation. Before and after gravity ventilation, I am trying to find a way to reduce the exposure dose of waiting patients according to a comparative analysis of horizontal spatial dose rates over time. Spatial dose ratio were measured for 10 minutes from various distances and angles around ventilator's location before and after gravity ventilation. Then, mean values, standard deviation and reduction ratio were calculated. The highest reduction rate of gravity ventilation was 95.31% and the highest reduction ratio was 1 to 3 minutes. Therefore, the gravity ventilation could reduce the exposure dose of radiologic technologists, waiting patients, patient guardians and nurses. In conclusion, the reduction of the exposure dose during the technegas ventilation study through gravity ventilation will play a role in optimiging the protection and it is in accordance with the recommended reduction of the medical exposure by ICRP 103.

• Journal of the Korean Society of Radiology
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• v.18 no.3
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• pp.301-307
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• 2024

The Study Evaluated Radiography Images using the Mastoid Process Axial Oblique Projection (Arcelin) imaging method for the Diagnosis of Pyramid Ridge, Mastoid Process, Mastoid Process air cells, Tympanum, Internal auditory and petrous in Supine Position. The subjective ROC (receiver operation characteristic) evaluation method was conducted on five Radiological technologists who have worked in the Image medical Department of University Hospitals for more than 8 years, and the Objective Evaluation, signal-to-noise Ratio (SNR), was evaluated and Analyzed. The Cronbach Alpha value was significantly higher at 0.816. In the Image ROC Evaluation Taken by Tilting the X-ray Tube 5°, 10°, 15° toward the leg by 10°, it Scored 34 points, and in the overall evaluation, the SNR scored high at 6,549. In Addition, In the Image Evaluation taken by Tilting the X-ray Tube 5°, 10°, and 15° toward the head, it Scored 32 points In the Image ROC Evaluation taken by tilting 5°, and in the Objective Evaluation, SNR received the highest score of 6,732.

• Journal of radiological science and technology
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• v.7 no.1
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• pp.3-11
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• 1984

The major findings of this investigation on radiographic works in 125 medical institutions around Seoul and Kyung-Ki area, from March 1983 to February 1984, are summarized as follows. 1. The number of references provided on radiographic techniques were 3 to 5 in general hospitals (52.1%), in hospitals (58.5%), and clinics (44.5%), and only the 10.4% of general hospitals had 11 or more. 2. The relatively high percentages of 75.0% of general hospitals and 68.3% of hospitals have established the standardized radiographic methods for regions examined, but most clinics (61.1%) have not. 3. As a log system for the radiographic request, the method of "routine study, or all the x-ray examinations are marked as 0 on a printed form" was most commonly used by general hospitals (62.5%) and hospitals (51.2%), and "the doctors employ their own methods" in most clinics (44.6%). 4. In the 85.4% of general hospitals, the 68.3% of hospitals and the 38.9% of clinics, the data such as diagnosis, clinic history, purpose of x-ray examination were recorded on a radiographic request at all times, or at least in part. 5. On a scale of hardness and easiness of order of doctors, the greatest response was "fairly easy to understand", and the 37.5% of general hospitals responded as "sometimes hard". 6. In determining the standards for radiographic factors, the general hospitals (62.5%) and hospitals (65.9%) adapted mostly "a departmental check list", and the clinics (61.1%) used mainly "a personal decision". 7. In using the immobilizing devices, angligner, and radiographic accessories, the Percentages were high in general hospitals and hospitals on the one hand, and were low in clinics on the other. 8. A consideration with regard to the devices for an improvement of examination of the same patients was totally ignored by the 50.0% of clinics, the 26.8% of hospitals and the 20.8% of general hospitals. 9. The causes of re-examination were due largely to patients (33.6%), and followed proportionately by incorrect exposure (22.8%), errors in positioning (22.0%), film processing faults (9.2%), conditions of x-ray equipments (8.8%), and quality of x-ray films (3.6%). 10. The conference on radiography was conducted regularly or irregularly by the 87.5% of general hospitals, the 56.1% of hospitals, and the 27.7% of clinics, and the meeting was proceeded only by radiologic technologists.

• Journal of radiological science and technology
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• v.26 no.2
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• pp.29-35
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• 2003

The purpose of this study was to compare the compression force and thickness of the compressed breast between mediolateral oblique and craniocaudal mammography. This population consisted of 204 paired mediolateral oblique and craniocaudal mammography obtained on one mammographic unit by certified mammography technologists during 2 month period. The women examined were $30{\sim}59$ years old with breast implants, the patients were classified into 3 groups according to age, $30{\sim}39$, $40{\sim}49$, and $50{\sim}59$, prior breast cancer, mastectomy or breast deformity were excluded. The digital readout of compressed breast compression force and thickness was recorded. Mammographic positioning was assessed using standard criteria. The mean compression force of the compressed breast on the craniocaudal projection was less than the mean compression force on the mediolateral projection(14 versus 13.88 daN, p<0.05). The mean thickness of the compressed breast for mediolateral projection was 41.46 mm and that for the craniocaudal projection was 39.50 mm(p<0.05). The compressed breast is higher or thicker on mediolateral oblique than on craniocaudal mammography.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.371-379
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• 2014

In this study, we conducted a survey on the limited examinations of the DR system to the 30 radiologic technologists engaging in the clinical sites and university hospitals in Daejeon metropolitan city from Oct. 15, 2012 to Nov. 15, 2012. Based on the survey results, we propose the conceptual design of a supplementary table for the conventional DR system to extend the examination capability and overcome the limitation of DR system. And, we evaluated the convenience and usefulness of the proposed table by applying it to five subjects. Ten experts were involved to evaluate the clinical usefulness of the obtained images. In this study, the experimental results show the feasibility to overcome the limited examination of the conventional DR system, and the proposed supplementary table may be beneficial to patients and hospitals.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.431-437
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• 2015

This convergence study analyzed the effectiveness of contrast agent reduction by normal saline solution dilution in the computed tomography of arteries of lower limb. 48 patients of 125 cc contrast agent and 30 patients of the same amount divided at a ratio of 7:3 for the contrast agent and normal saline solution were studied. The average attenuation coefficient(HU) and signal to noise ratio(SNR) of abdominal aorta, femoral artery, popliteal artery and posterior tibial artery at each image were evaluated quantitatively and the four criteria in the five point scale was conducted qualitatively by two radiologists and four radiological technologists. In the quantitative evaluation, both HU and SNR had high average score before dilation but there were no statistical significance by independent t-test(p>0.05). In the qualitative evaluation, there were a little differences in the average scores between 4.86~4.77 of original contrast agent and 4.83~4.67 of dilated contrast agent but there were no statistical significance(p>0.05). In the computed tomography of arteries of lower limb, the dilated contrast agent doesn't influence image quality and reduces overall contrast agent and lowers iodine content per unit of molecular therefore will contribute to decrease side effect of contrast agent.

• The Korean Society of Law and Medicine
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• v.22 no.3
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• pp.97-124
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• 2021

In medical institutions, there are radiation-related workers such as radiological technologists, physicians, dentists, and dental hygienists who handle diagnostic radiation generators. Also, there are work assistants, such as nurses and assistant nurses, who assist in radiation treatment or transfer patients to the radiation examination room. Radiation exposure management for radiation-related workers is carried out under the 「Medical Service Act」, but there is no legal basis for work assistants, etc. And the management of radiation exposure for diagnosis is regulated by the 「Medical Service Act」, and the management of radiation exposure by therapeutic radiation and nuclear medical examination is governed by the 「Nuclear Safety Act」. Thus, to improve the management of radiation exposure for diagnosis, the regulations on radiation exposure management for diagnosis under the 「Medical Service Act」 were compared and reviewed with those of the 「Nuclear Safety Act」. As a result, the main contents are as follows. First, it is necessary to legislate to include nurses, assistant nurses, and clinical practice students who are likely to be exposed to radiation besides radiationrelated workers as subjects of radiation exposure management for diagnosis. Second, when a radiation-related worker for diagnosis is confirmed to be pregnant, the exposure dose limit should be defined. Third, it is necessary to revise the regulations on the types of personal exposure dosimeters in the 「Rules on the Safety Management of Radiation Generators for Diagnostics」. Fourth, it seems that health examination items for radiation-related workers, radiation workers, and frequent visitors should be the same. Fifth, It is necessary to unify and regulate diagnostic radiation and all medical radiation, including therapeutic radiation and nuclear medicine, in one legal system.

• Journal of radiological science and technology
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• v.6 no.1
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• pp.117-129
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• 1983

This study, in order to improve clinical and practical trainings in the education of radiologic technologists, applies to 76 medical institutions of 91 ones which are used as the hospitals of clinical and practical training in 9 existing junior colleges except 3 new ones of 12 ones throughout all over the country from November 1, in 1982 to April 30, in 1983. And the purpose of this study is to research the percent conditions of basic practical trainings and clinical ones enforced in each college, and the percent conditions, equipments, contents, and opinions in clinical and practical trainings enforced in each hospital. The results are summarized as follows; 1. In the case of junior colleges in the whole country the curriculum of basic practical trainings averages 336.66 hours and the limits are between 120 and 510 hours. The actual hours in practice average 140 hours and the limits are between 60 and 240 hours, which correspond to 41.58% of the curriculum of basic practical trainings. 2. There were three junior colleges among nine that had a reserved hospital for clinical and practical trainings(only 33.33%). 3. The period of the practice was almost vacation in 4 junior colleges. The practice was conducted only for students to want the practice(44.45%), junior colleges that all students in them conducted the practice was 2 junior colleges and presented 22.22%. 4. In the field of students engaging in the practice, each field of radiation therapy and nuclear medicine presented 16.5%, 20.3% and almost students didin't have experience for the practice. 5. In medical institutions the educational institutions for intern showed 67.11%. Hospital with radiologist showed 26.32%. Radiotechnologist who had experience below 5 years presented 60.17%. 6. In the equipment for radiation diagnosis, each hospital had no difference. The number of hospitals passessing diagnostic equipments above 125 KVP was 56.26%. But radiation therapy equipment and nuclear medicine equipment had extremely low rate. 7. In the diagnosis of patient in the practice hospital, conventional radiography-to Skull, Chest, Abdomen, Skeleton, Urogenital system-reached the criterion. But special radiography was comparatively low. There appeared low rate, 32.89% in the field of nuclear medicine, 15.79% in the field of radiation therapy. 8. Students who carried out the practice were 1-89 students, days in practice were 1-30 days. There were differences in that point among among hospitals. Junior colleges conducting the practice were 2 colleges per hospital. Scope of the object were 1-8 junior colleges. 9. The practice conducted for the request of the colleges presented 72.37%, in addition, The prctices were conducted for growth of the younger generation and the same coperation with the colleges establishment of sisterhood with the colleges, relationship with students. 10. The practice conducted without the establishment of plan presented 59.21% The need for guiding book to the practice and evaluating was recognized over 90%. 11. In the relation between the practice with achievement of credit. There were big differences in opinion between hospitals-Group and the colleges-Group; hospital-Group had opinion that must follow achievement of credit with the practice. The colleges-Group had opinion that must conduct the practice after achieving credit. 12. After conducting the practice, in the practice leaders satisfaction degree dissatisfactory opinion presented the most rate 80.26%. Very much satisfactory opinion, as one hospital, presentd only 1.32%. 13. Both hospitals-Group and the colleges-Group had an opinion that the practice leader must have actual experiences, lectures and achievement, an opinion that actual experiences is over 5 years. 14. In the guide of human relation, cooperation, responsibility, courtesy to patients. Both hospitals-Group and the colleges-Group had an opinion that the guide must be involved in the period of the practice and must be instructed.