• Journal of the Korean Society of Radiology
• /
• v.12 no.7
• /
• pp.887-893
• /
• 2018

The purpose of this study is to compare the performance of X-ray generators installed in hospitals and universities and apply the quality control items of diagnostic X-ray generators to recognize the importance of periodic performance management. First, the reproducibility and linearity test results showed that the PAE of the reproducibility evaluation was high for the GX-650 devices that met the acceptance criteria in all the experimental conditions and lacked the periodic quality control. In the linearity evaluation, when the tube voltage was set to 100 kVp, It was measured to deviate from the error. In addition, it was found that the PAE in the low-accuracy evaluation results relative to an X-ray tube voltage and tube current of the device low occurrence frequency. The HVL experiment was included in all of the devices at the HVL by tube voltage. Therefore, it is necessary to recognize the importance of quality control of all devices rather than hospital and laboratory, and to manage the device performance by actively managing the device, and to establish a short - term quality control system like special medical devices.

• Journal of Radiation Protection and Research
• /
• v.37 no.1
• /
• pp.25-34
• /
• 2012

To know which parameters were acceptable for achieving lowest radiation exposure to the patients and highest image quality at the diagnostic X-ray radiography, we measured the patient radiation dose and image quality in transmitted PACS (Picture Archiving and Communication System) at variable combinations of the added filters. As a result, the Dose Area Product (DAP: $mGy{\cdot}cm^2$) and Entrance Surface Doses (ESDs: $mGy$) was lowest at 1 mmAl + 0.2 mmCu and highest at 0 mmAl. The histogram of the image quality by transmitted PACS was not significantly different at variable combinations of exposure parameters on the MATLAB. In conclusion, this study can be helpful for expecting radiation dose-exposure and control exposure parameters for the diagnostic X-ray radiography.

• Transactions on Electrical and Electronic Materials
• /
• v.4 no.3
• /
• pp.10-14
• /
• 2003

In this paper, we have introduced the x-ray detector built with a CsI:Na scintillation layer deposited on amorphous selenium. To determine the thickness of the CsI:Na layer, we have estimated the transmission spectra and the absorption of continuous x-rays in diagnostic range by using computer simulation (MCNP 4C). A x-ray detector with 65 ${\mu}m$-CsI:Na/30 ${\mu}m$-Se layer has been fabricated by a thermal evaporation technique. SEM and PL measurements have been performed. The dark current and x-ray sensitivity of the fabricated detector has been compared with that of the conventional a-Se detector with 100 ${\mu}m$ thickness. Experimental results show that both detectors exhibit a similar dark current, which was of a low value below $400 pA/cm^2$ at 10 V/${\mu}m$. However, the CsI:Na-Se detector indicates high x-ray sensitivity, roughly 1.3 times that of a conventional a-Se detector. Furthermore, a CsI:Na-Se detector with an aluminium reflective layer shows a 1.8 times higher x-ray sensitivity than an a-Se detector. The hybrid type detector proposed in this work exhibits a low dark current and high x-ray sensitivity, and, in particular, excellent linearity to the x-ray exposure dose.

• Journal of radiological science and technology
• /
• v.17 no.2
• /
• pp.21-27
• /
• 1994

In this pauper, when the X-ray exposure condition is 70, 90, 110 kV, 10 mAs, FFD 180 cm, FSO $10{\times}10$, $35{\times}35\;cm$, toward the $36{\times}36{\times}15\;cm$ acryl phantom, the free space scatter dose rate at the 15th points in X-ray diagnostic room was measured by electrometer and 1800 co ionization chamber. Therefore, the free space scatter dose distribution profile was drown, and then, the free space scatter dose contribution percentage was Investigated. The obtained results are summarized as following. 1. The X-ray tube leakage dose rate of the experiment generator at the 1 m from focus was measured maximum 85 mR/hr, minimum 20 mR/hr, therefore, this values was appeared below the KS rules, 2. The free space scatter dose become to larger at the primary X-ray beam around area, and lower at the back ward X-ray tube. The maximum values were 3,812 mR/hr at the front Lt 1 m $45^{\circ}$ point, minimum 117 mR/hr at the back ward 1 m $180^{\circ}C$ point. 3. As the more tube voltage and field size increase, the more free space scatter dose contribution percentage become to increase, as to 90 kV from 70 kV, increase to 12 %, to 110 kV from 90 kV, increase to 18 %, and then, become to 11 % at the $10{\times}10\;cm$ and 87 % at the $35{\times}35\;cm$. 4. The 89 % of the total producted scatter ray occured from acryl phantom, at the X-ray tube housing 6 %, at the front side back wall 5 %. 5. The free space scatter dose contribution percentage at the one point build up 80 % from the phanton direction, 14 % from the X-ray tube and collimator direction, 2.2 % from the front wall, 1.8 % from the side wall, 1.7 % the back wall.

• The Journal of Internal Korean Medicine
• /
• v.41 no.5
• /
• pp.734-739
• /
• 2020

Objectives: The purpose of this study was to propose a diagnostic method for classifying patients with dyspepsia by symptom type. The correlation between symptom types and X-ray findings was studied in 62 patients with indigestion. Methods: In this study, the complaints and abdominal X-ray findings were collected for 62 patients who visited the outpatient Korean medicine clinic. The medical information related to dyspepsia was grouped for similar patients and classified by symptom type. Results: The patients with dyspepsia were classified into three types according to their medical symptoms: Distention type (N=43, 68.3%), Abdominal Pain type (N=16, 25.5%), and Constipation type (N=12, 19.0%). Intestinal fecal findings (80.6%) on x-rays were noted in most of the cases, followed by intestinal gas pattern findings (14.5%). Conclusion: Classifying patients with dyspepsia by symptom types is an appropriate diagnostic method due to the unclear pathophysiology of indigestion and the difficulty in applying a Korean medical dialectic. Irrespective of the symptom types, the large number of fecal material findings (80.6%) on x-rays means an effect on the interior environment of the body where intestinal feces accumulate easily and decreased gastrointestinal motility in patients with indigestion. This can be correlated with "food accumulation (食積)" as intestinal feces are tangible substances. In addition, gas in the intestine increases visceral sensitivity, causing abdominal distention or pain. The gas pattern findings (14.5%) on x-ray were observed in the "Distention type" and "Abdominal pain type," but not in the "Constipation type."

• Journal of radiological science and technology
• /
• v.11 no.2
• /
• pp.27-64
• /
• 1988

Most hospital administrators in our country have doubted whether or not the size of their hospital personnel staffs, and the personnel management styles implemented are efficient or not. Actually, increased personnel expenditures due to sophisticated specialization of medical practices has become the biggest hospital expense. Therefore, it is said that hospitals can be run move efficiently by implementing reasonable management strategies for hospital personnel management. In this paper, the departments of diagnostic radiography in 16 general hospitals in Seoul, which were classified into 4 groups by the scale of hospital beds, were used as sample cases. Then, the data for the number of X-ray examination by diagnostic item was collected from sample hospitals. The unit hour spent on X-ray examinations in each diagnostic service was quoted from "A Study on setting-up of the relative value units of medical services and on the structure of current fee schedules" written by Mr. Ik Je Seong. The data analysis results are as follows; First, the number of hours per day spent on X-ray examinations in 13 hospitals out of 16 hospitals, was shorter than the general daily working hours (8 hours). Second, in the morning there was not enough time to work for X-ray examinations required, with the available manpower. In the afternoon, however, the situation was diametrically opposed to that in the morning. Third, in light of above results, though most hospitals employ sufficient personnel for the quantity of the actural work, they were always short-handed where their works were performed Fourth, this study tells us that there is a maldistribution of the work in the schedule : too much work for the available personnel in the morning. The following recommendations are resulted from the data analysis described above. First, it is recommended that all out-patients coming again, except specific patients(G. B. or I.V.P. etc) who have to have their X-ray examinations on an empty stomach in the morning among out-patients, be required to visit the hospital in the afternoon. Second, it is recommended that all new out-patients be required to make a reservation in order to equalize the number of patients throughout the day. Third, it is recommended that all in-patients, except specified patients, be arranged to have their X-ray examinations in the afternoon. Fourth, it is recommended that part time workers be employed during peak hours. This recommendation, if applied in a wider scale, would allow hospitals to overcome the problem of the maldistribution of work and personnel, and then more efficient hospital management through the appropirate personnel management procedures could be expected.

• Publications of The Korean Astronomical Society
• /
• v.15 no.spc1
• /
• pp.113-118
• /
• 2000

A magnetic cataclysmic variable has a rotating magnetic white dwarf which accretes matter from its late type companion. Kim & Beuermann (1995) presented a phenomenological model of the accretion from its surrounding structure e.g., a disk into the magnetosphere of the white dwarf, and presented results for the spin modulated X-ray spectrum and light curves. Using this model, we calculate the optical continuum and line emission which result from reprocessing of X-rays in the accretion stream within the magnetosphere. Penning (1985) suggested the observed spin-modulated radial-velocity variations might result from reprocession of X-rays in the disk. We, however, find the radiation can be originated from the magnetosphere accretion stream. We use the same geometrical model to calculate the optical and the X-ray behaviour. The results from the two wavelength bands are internally consistent. We conclude that this approach will increase the diagnostic accuracies of the results.

• Journal of radiological science and technology
• /
• v.15 no.1
• /
• pp.89-97
• /
• 1992

X-ray quality is identified numerically by half value layer(H.V.L) and the HVL is affected by the kVp and the amount of filtration in the useful beam. X-ray quality evaluated by H.L.D is influenced by kVp and filtration. Author had several experiments with phantom in diameter of 8 cm normal adult chest, for reduction of radiation dose of the patients in diagnostic radiology and got some results. 1. H.V.L is increased the thicker the filter and the higher the kVp. 2. If the kVp is increased from 60 to 120, the skin dose can be reduced as 34%(Skin dose of 60 kVp with 4 mmAl filter : 100%). 3. If the 4 mmAl filter with 60 kVp is added to x-ray tube, skin dose can be reduced as 23% than no filter. 4. Therefore high kVp and filtration can increase output to input dose ratio and 120 kVp and 4 mmAl filter were most effective for reduction of patient dose in chest radiography.

• Korean Journal of Radiology
• /
• v.23 no.9
• /
• pp.854-865
• /
• 2022

Photon-counting detector (PCD) CT is a new CT technology utilizing a direct conversion X-ray detector, where incident X-ray photon energies are directly recorded as electronical signals. The design of the photon-counting detector itself facilitates improvements in spatial resolution (via smaller detector pixel design) and iodine signal (via count weighting) while still permitting multi-energy imaging. PCD-CT can eliminate electronic noise and reduce artifacts due to the use of energy thresholds. Improved dose efficiency is important for low dose CT and pediatric imaging. The ultra-high spatial resolution of PCD-CT design permits lower dose scanning for all body regions and is particularly helpful in identifying important imaging findings in thoracic and musculoskeletal CT. Improved iodine signal may be helpful for low contrast tasks in abdominal imaging. Virtual monoenergetic images and material classification will assist with numerous diagnostic tasks in abdominal, musculoskeletal, and cardiovascular imaging. Dual-source PCD-CT permits multi-energy CT images of the heart and coronary arteries at high temporal resolution. In this special review article, we review the clinical benefits of this technology across a wide variety of radiological subspecialties.

• Journal of radiological science and technology
• /
• v.2 no.1
• /
• pp.85-88
• /
• 1979

When X-radiation passes through the human body; some is transmitted some is truly absorbed, and some is scattered. In diagnostic radiography, scattered radiation can reach the film if no protective measures are taken. This scattered ray increased density which not necessary for image formation. We studied about absorbtion, scattered ray and the way of get rid of scatter ray according to the x-ray tube kilovoltage and obtained results as follow; 1. Absorbtion ray increased proportion to KVP. 2. Scattered ray increased at high KVP and thick object. 3. Secondary radiation of the primary increased at high KVP and thick object. 4. Remove .ate of scattered ray decreased at thick object and increase at low KVP make use of 6:1 grid ratio