• Journal of radiological science and technology
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• v.31 no.1
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• pp.17-23
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• 2008

Purpose : Because there is a difference depending on the environment as for an inspection equipment the important part of bone density scan and the precision/accuracy of a tester, the management of quality must be made systematically. The equipment failure caused by overload effect due to the aged equipment and the increase of a patient was made frequently. Thus, the replacement of equipment and additional purchases of new bonedensity equipment caused a compatibility problem in tracking patients. This study wants to know whether the clinical changes of patient's bonedensity can be accurately and precisely reflected when used it compatiblly like the existing equipment after equipment replacement and expansion. Materials and methods : Two equipments of GE Lunar Prodigy Advance(P1 and P2) and the Phantom HOLOGIC Spine Road(HSP) were used to measure equipment precision. Each device scans 20 times so that precision data was acquired from the phantom(Group 1). The precision of a tester was measured by shooting twice the same patient, every 15 members from each of the target equipment in 120 women(average age 48.78, 20-60 years old)(Group 2). In addition, the measurement of the precision of a tester and the cross-calibration data were made by scanning 20 times in each of the equipment using HSP, based on the data obtained from the management of quality using phantom(ASP) every morning (Group 3). The same patient was shot only once in one equipment alternately to make the measurement of the precision of a tester and the cross-calibration data in 120 women(average age 48.78, 20-60 years old)(Group 4). Results : It is steady equipment according to daily Q.C Data with $0.996\;g/cm^2$, change value(%CV) 0.08. The mean${\pm}$SD and a %CV price are ALP in Group 1(P1 : $1.064{\pm}0.002\;g/cm^2$, $%CV=0.190\;g/cm^2$, P2 : $1.061{\pm}0.003\;g/cm^2$, %CV=0.192). The mean${\pm}$SD and a %CV price are P1 : $1.187{\pm}0.002\;g/cm^2$, $%CV=0.164\;g/cm^2$, P2 : $1.198{\pm}0.002\;g/cm^2$, %CV=0.163 in Group 2. The average error${\pm}$2SD and %CV are P1 - (spine: $0.001{\pm}0.03\;g/cm^2$, %CV=0.94, Femur: $0.001{\pm}0.019\;g/cm^2$, %CV=0.96), P2 - (spine: $0.002{\pm}0.018\;g/cm^2$, %CV=0.55, Femur: $0.001{\pm}0.013\;g/cm^2$, %CV=0.48) in Group 3. The average error${\pm}2SD$, %CV, and r value was spine : $0.006{\pm}0.024\;g/cm^2$, %CV=0.86, r=0.995, Femur: $0{\pm}0.014\;g/cm^2$, %CV=0.54, r=0.998 in Group 4. Conclusion: Both LUNAR ASP CV% and HOLOGIC Spine Phantom are included in the normal range of error of ${\pm}2%$ defined in ISCD. BMD measurement keeps a relatively constant value, so showing excellent repeatability. The Phantom has homogeneous characteristics, but it has limitations to reflect the clinical part including variations in patient's body weight or body fat. As a result, it is believed that quality control using Phantom will be useful to check mis-calibration of the equipment used. A value measured a patient two times with one equipment, and that of double-crossed two equipment are all included within 2SD Value in the Bland - Altman Graph compared results of Group 3 with Group 4. The r value of 0.99 or higher in Linear regression analysis(Regression Analysis) indicated high precision and correlation. Therefore, it revealed that two compatible equipment did not affect in tracking the patients. Regular testing equipment and capabilities of a tester, then appropriate calibration will have to be achieved in order to calculate confidential BMD.

• Journal of radiological science and technology
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• v.38 no.1
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• pp.23-30
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• 2015

Positron emission tomography scan has been growing diagnostic equipment in the development of medical imaging system. Compare to 99mTc emitting 140 keV, Positron emission radionuclide emits 511 keV gamma rays. Because of this high energy, it needs to reduce radioactive emitting from patients for radio technologist. We searched the external dose rates by changing distance from patients and measure the external dose rates when we used shielder investigate change external dose rates. In this study, the external dose distribution were analyzed in order to help managing radiation protection of radio technologists. Ten patients were searched (mean age: $47.7{\pm}6.6$, mean height: $165.5{\pm}3.8cm$, mean weight: $65.9{\pm}1.4kg$). Radiation was measured on the location of head, chest, abdomen, knees and toes at the distance of 10, 50, 100, 150, and 200 cm, respectively. Then, all the procedure was given with a portable radiation shielding on the location of head, chest, and abdomen at the distance of 100, 150, and 200 cm and transmittance was calculated. In 10 cm, head ($105.40{\mu}Sv/h$) was the highest and foot($15.85{\mu}Sv/h$) was the lowest. In 200 cm, head, chest, and abdomen showed similar. On head, the measured dose rates were $9.56{\mu}Sv/h$, $5.23{\mu}Sv/h$, and $3.40{\mu}Sv/h$ in 100, 150, and 200 cm, respectively. When using shielder, it shows $2.24{\mu}Sv/h$, $1.67{\mu}Sv/h$, and $1.27{\mu}Sv/h$ in 100, 150, and 200 cm on head. On chest, the measured dose rates were $8.54{\mu}Sv/h$, $4.90{\mu}Sv/h$, $3.44{\mu}Sv/h$ in 100, 150, and 200 cm, respectively. When using shielder, it shows $2.27{\mu}Sv/h$, $1.34{\mu}Sv/h$, and $1.13{\mu}Sv/h$ in 100, 150, and 200 cm on chest. On abdomen, the measured dose rates were $9.83{\mu}Sv/h$, $5.15{\mu}Sv/h$, and $3.18{\mu}Sv/h$ in 100, 150, and 200 cm, respectively. When using shielder, it shows $2.60{\mu}Sv/h$, $1.75{\mu}Sv/h$, and $1.23{\mu}Sv/h$ in 100, 150, and 200 cm on abdomen. Transmittance was increased as the distance was expanded. As the distance was further, the radiation dose were reduced. When using shielder, the dose were reduced as one-forth of without shielder. The Radio technologists are exposed of radioactivity and there were limitations on reducing the distance with Therefore, the proper shielding will be able to decrease radiation dose to the technologists.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.2
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• pp.101-108
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• 2017

Purpose: The proton used in proton therapy has a characteristic of giving a small dose to the normal tissue in front of the tumor site while forming a Bragg peak at the cancer tissue site and giving up the maximum dose and disappearing immediately. It is very important to verify the proton arrival position. In this study, we used the off-line PET CT method to measure the distribution of positron emitted from nucleons such as 11C (half-life = 20 min), 150 (half-life = 2 min) and 13N The range and distal falloff point of the proton were verified by measurement. Materials and Methods: In the IEC 2001 Body Phantom, 37 mm, 28 mm, and 22 mm spheres were inserted. The phantom was filled with water to obtain a CT image for each sphere size. To verify the proton range and distal falloff points, As a treatment planning system, SOBP were set at 46 mm on 37 mm sphere, 37 mm on 28 mm, and 33 mm on 22 mm sphere for each sphere size. The proton was scanned in the same center with a single beam of Gantry 0 degree by the scanning method. The phantom was scanned using PET-CT equipment. In the PET-CT image acquisition method, 50 images were acquired per minute, four ROIs including the spheres in the phantom were set, and 10 images were reconstructed. The activity profile according to the depth was compared to the dose profile according to the sphere size established in the treatment plan Results: The PET-CT activity profile decreased rapidly at the distal falloff position in the 37 mm, 28 mm, and 22 mm spheres as well as the dose profile. However, in the SOBP section, which is a range for evaluating the range, the results in the proximal part of the activity profile are different from those of the dose profile, and the distal falloff position is compared with the proton therapy plan and PET-CT As a result, the maximum difference of 1.4 mm at the 50 % point of the Max dose, 1.1 mm at the 45 % point at the 28 mm sphere, and the difference at the 22 mm sphere at the maximum point of 1.2 mm were all less than 1.5 mm in the 37 mm sphere. Conclusion: To maximize the advantages of proton therapy, it is very important to verify the range of the proton beam. In this study, the proton range was confirmed by the SOBP and the distal falloff position of the proton beam using PET-CT. As a result, the difference of the distally falloff position between the activity distribution measured by PET-CT and the proton therapy plan was 1.4 mm, respectively. This may be used as a reference for the dose margin applied in the proton therapy plan.

• Journal of radiological science and technology
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• v.6 no.1
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• pp.131-181
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• 1983

After the investigation on, and the analysis of, the educational system for medical technicians and the present educational situation for medical technologies in this country, the following conclusions were drawn. 1. As of March 1983 the current academic system for education in medical technologies included the regular 4-year college courses and those of the 2-year professional junior college courses. But except in the cases on clinical pathology and physical therapy, there were no college-level departments. Particularly, no educational institutions, at whatever level, had a department for working therapies. 2. The total number of credits needed for graduation from a department of medical technologies was 150 points at a regular 4-year college and 85 to 96 points at a 2-year professional college. The obligatory minimum number of credits for a student at a professional college was set at 80 points and above. 3. As for the number of the educational institutions for medical technologies in this country, there were one regular college and 14 professional colleges, a total of 15 institutions. As many as 14 colleges had departments of clinical pathology, 12 had departments of Radiotechnology, 11 had departments of physical therapy, 12 had departments of dental technology, and eight had departments of dental hygiene. 4. The total capacity of the professional colleges in admitting new enrollment each year were 1,920 for clinical pathology, 1,552 for radiology, 1,012 for physical therapy, 1,334 for dental technologies, 828 for dental hygiene, an aggregate of 6,646 for all of the professional college departments. 5. The total number of graduates from the 12 professional colleges by department during the period of 1965-83 were 7,595 for clindical pathology, 4,768 for radiology, 2,821 for physical therapy, 3,000 for dental technologies, and 1,787 for dental hygiene, totalling 19,971 for all departments in the professional colleges. 6. In the state examination for licensed medical technicians, 12,446 have passed from among the total of 26,609 participants, representing a 45% passing ratio. By departments the ratios showed 44% for clinical pathology, 39.7% for radiology, 51.2% for physical therapy, 42.5% for dental technology, 72.5% for dental hygiene and 73.1% for working therapy. 7. As for the degree of satisfaction shown by the people in this field, 52.2 percent of the teaching staffs who responed to the questionaires said they were satisfied with their present profession, while the great majority of medical technicians(66%) replied that they were indifferent to the problem. 8. The degree of satisfaction shown by the students on their enrollment in this particular academic field was generally in the framework of indifference(43.7%), but mere students(36.5%) were satisfied with their choice than those were not satisfied(14.4%) 9. As for the student's opinions on the lectures and practicing hours, a good many students replied that, among such courses as general science and humanities courses the basic medical course, the major course and practicing hours, the hours provided for the general courses(47.1%) and practicing(47.6%) were insufficient. 10. When asked about the contents of their major courses, comparatively few students (23.6%) replied that the courses were too difficult, while a convincing majority(58.5%) said they were neither difficult nor easy. As for the appropriateness of the number of the present teaching staffs, a great majority(71.0%) of the students replied that the level of the teaching personnel in each particular field was insufficient. 11. Among the students who responded to the poll, good part of them(49.5%) wanted mandatory clinical practicing hours, and the the majority of them(64.6%) held the view that the experimental and practicing facilities of their schools were insufficient. 12. On the necessity of the attached hospitals, 71.1% of the teaching staffs and 58.0% of the medical technicians had the opinion that this kind of facility was indispensable. 13. As for the qualifications for applicants to the state examination in the licensing system for medical technicians, 52.2% of the teacher's and 36% of the medical technicians replied that the present system granting the qualifications according to the apprenticeship period should be abolished. 14. On the necessity of improving the present system for education in medical technologies, an overwhelming majority(94.4% of the :caching staffs, 92.0% of the medical technicians and 91.9% of students) of these polled replied that the present system should be changed for the better. 15. On the method of changes for the present educational system, a great majority(89.4% of the teaching staffs, 80.4% of the medical technicians and 90.1% of the students) said that the system must be changed so that it fits into the reality of the present day. 16. As for the present 2-year program for the professional colleges, 61.6% of the teachers, 72.0% of the medical technicians and 38.8% of the students expressed the hope that the academic period would be extended to four regular years, hemming a full-fledged collegelevels program. 17. On the life-long eductional system for medical technicians, there was a considerable number of people who expressed the hope that an open university system(38.9% of the teaching staffs, 36.0% of the medical technicians) and a graduate school system would be set up. 18. As for the future prospects for medical technicians as professionals, the optimists ana pessimists were almost equally divided, and 41.1% of the teaching staffs 36.0% of. the technicians and 50.5% of the students expressed an intermediate position on this issue.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.5 no.1
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• pp.51-61
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• 2002

Purpose: The most common causes of neonatal cholestasis are neonatal hepatitis (NH) and extrahepatic biliary atresia (EHBA). Since neonatal cholestasis presents with variable expression of same pathologic process and has similar clinical, biochemical, and histologic features between EHBA and idiopathic neonatal hepatitis (NH), differential diagnosis is often difficult. We reviewed the differences of clinical characteristics and laboratory data to find out any correlation between the results of $Tc^{99m}$ DISIDA scan and presence of acholic stool. Methods: Between June 1993 and January 2001, total 29 infants younger than 4 month-old underwent $Tc^{99m}$ DISIDA scan. Their biochemical tests and clinical course were reviewed retrospectively. Results: Patients who had negative intestinal activity on $Tc^{99m}$ DISIDA scan showed acholic stool and revealed higher serum direct bilirubin and urine bilirubin level. 18.2% of patients with acholic stool showed intestinal activity on $Tc^{99m}$ DISIDA scan and 81.8% of them did not. All the patients without acholic stool showed positive intestinal activity on $Tc^{99m}$ DISIDA scan. The result of $Tc^{99m}$ DISIDA scan and the presence of acholic stool showed high negative correlation (r :-0.858). Patients with acholic stool and negative intestinal activity on $Tc^{99m}$ DISIDA scan showed higher serum total bilirubin level. Patients without acholic stool and positive intestinal activity on $Tc^{99m}$ DISIDA scan showed higher serum level of ALT. Conclusion: Patients with acholic stool and negative intestinal activity showed high correlation, but 18.2% of patients with acholic stool showed positive intestinal activity. So operative cholangiogram or transcutaneous liver biopsy should be performed for confirmation.