The purpose of this study was to compare and analyze the patient dose according to the distance between the X-ray tube focus and the image receptor, and to propose a new method for quantitatively evaluating the image quality. Using this quantitative evaluation method, the optimal distance for increasing x-ray image quality with low radiation dose was estimated between source and image receptor in Rib series radiography. Phantom images were obtained by changing the distance between focus and image receptor (100 cm and 180 cm). The patient radiation dose was estimated using entrance surface dose and dose area product. In order to evaluate image quality objectively, a non - reference image evaluation method was employed with paper and salt noise and Gaussian filter. As a result of this study, when the SID was changed from 100 cm to 180 cm, the entrance surface dose decreased by 4 ~ 5 times and the dose area product decreased by 3 times. In addition, there is no significant difference in image quality between of SID 180 cm and SID 100 cm. In conclusion, it was demonstrated that performing the rib series radiography at SID 180 cm is an optimal method to reduce the exposure dose and improve the image quality.

Mobile X-ray generators are used not in the radiation area but in open space, which causes the exposure of secondary radiation to the healthcare professionals, patients, guardians, etc., regardless of their intentions. This study aimed to investigate the shielding effect of the developed radiation restrictor to block the secondary radiation scattered during the use of mobile X-ray generator. Upon setting the condition of mobile X-ray generator with chest AP, spatial doses were measured by the existence of human equivalent phantom and radiation restrictor, and measured by the existences of phantom and radiation restrictor at the same length of 100 cm. Measurements were taken at intervals of 10 cm every $30^{\circ}$ from $-90^{\circ}$ (head direction) to $+90^{\circ}$ (body direction). Upon the study results, spatial doses in all direction were increased by 45% on average when using phantom in the same condition, however, they were decreased by 64% on average when using the developed radiation restrictor. The dose at 100 cm from the center of X-ray was $3.0{\pm}0.08{\mu}Gy$ without phantom and was increased by 40% with $4.2{\pm}0.08{\mu}Gy$ after phantom usage. The dose when using phantom and the developed radiation restrictor was $1.4{\pm}0.08{\mu}Gy$, which was decreased by 66% compared to the case without using them. Therefore, it is considered the scattered radiation can be shielded at 100-150 cm, the regulation of the distance between beds, effectively with the developed radiation restrictor when using mobile X-ray generators, which can lower the radiation exposure to the people nearby including healthcare professionals and patients.

We will provide basic data on the evaluation of patient dose in terms of DECT quality control by comparing the equipment-provided dose with the measured dose according to the configuration method of the X-ray generator by the manufacturer of the dual-energy CT unit. For computed tomography (CT) equipment, Discovery 750HD, Aquilion ONE GENESIS Edition, and Somatom Definition Flash were used. The $CTDI_{vol}$ value was measured by inserting the Unfors Xi ion chamber into a 32 cm PMMA acryl Phantom. The results of estimated $CTDI_{vol}$ DECT and measured $CTDI_{vol}$ showed that the dose difference between DECT 80 + 140 kVp of G company was at least 0.51% and -1.90% max, and measured $CTDI_{vol}$ was slightly lower (p<0.05). The difference of 80 + 140 kVp of S company was the minimum of 5.84% and the maximum of 7.52% (p<0.05). The measured $CTDI_{vol}$ was less than estimated $CTDI_{vol}$. The C company's 80 + 135 kVp showed a difference of at least 7.58% and a maximum of 13.58% (P<0.05), and all of measured $CTDI_{vol}$ was less. The linearity of exposure dose for all DECT equipment was very linearly reflected with $R^2$ being 0.97 or above, and the measured dose of the ionization chamber was less than the predicted dose of the monitor.

Magnetic Resonance Imaging for patients with metallic implant has poor image quality, and signal loss and artifacts including distortion can occur. The purpose of this study is to carry out a comparative evaluation on high receive bandwidth(hiBW), O-MAR, O-MAR XD to reduce artifacts in knee implant. To take MRI, 3.0T scanner and dual-source radiofrequency transmission were used. O-MAR XD technique's strong option showed a significant difference (p<0.001) with O-MAR XD technique's weak option, O-MAR and hiBW excluding the medium option. O-MAR XD's medium option had a significant difference (p<0.01) with O-MAR XD's weak, O-MAR and hiBW. O-MAR XD technique's weak option had a significant difference (p<0.01) with O-MAR XD's strong and medium options, O-MAR and hiBW. O-MAR technique had a significant difference (p<0.001) with strong, medium, weak options of O-MAR XD technique except for hiBW. HiBW had a significant difference (p<0.001) with strong, medium and weak options of O-MAR XD technique except for O-MAR. The results showed that O-MAR XD technique was more useful for MRI scan for patients with knee replacement surgery than traditional techniques such as hiBW or O-MAR, and susceptibility artifacts decreased more when O-MAR XD technique's strong or medium option was applied. Based on the results above, it is considered that it will be possible to acquire images whose susceptibility artifacts were highly decreased by using O-MAR XD technique's strong or medium option when conducting MRI for artificial knee joint and it will be helpful for checking and monitoring patients with knee joint replacement.

Unlike the traditional Radiological examinations, Magnetic Resonance Imaging (MRI) does not cause any harm and high levels of Radiation to the human body. Furthermore, MRI is widely used owing to its ability to adapt to different situations. However, the MRI equipment creates noises from its mechanical parts, and its magnetic bore structure can cause anxiety and claustrophobia in patients. To relieve claustrophobia, commercial refraction glasses were provided to the participants in this study, and the changes in anxiety and claustrophobia were measured. The participants were 30 volunteers with claustrophobia. To measure anxiety, the participants were asked to answer a Visual Analogue Scale (VAS) questionnaire. The physical markers of discomfort included perspiration on the forehead or hands (46.7%), mild frowning (30.3%), and leg shaking (40.1%). The subjective markers of discomfort included dizziness (2.85% in the men and 1.75% in the women). Although fear and anxiety levels were observed to be higher in the men, the difference was not significant. Hence, it was determined that both men and women felt discomfort (p >0.5). The fear coefficient was observed to decrease from 7.67 prior to wearing refraction glasses to 2.42 after wearing refraction glasses (p<0.000). In addition, use of refraction glass decreased MRI aversion from 1.97 to 1.03 (p<0.000). It can be inferred that refraction glasses are beneficial to patients undergoing MRI.

There was a shortage of research reports on sterilization criterion and contamination of ultrasonic probes. Therefore, in this study, we were going to provide a basic study to measure the level of microbial contamination in ultrasonic probes and to investigate the radiographer's awareness of infection. After the scan, samples were collected from the rubber part of the probe by opening a sterile swab (Transport Medium AM608-1S) for medical bacteria collection with the remaining gel removed with a paper towel. Also, the collected samples of bacteria were grown for seven days and then the laboratory was analyzed. Among the total 29 types of microorganisms, Micrococcus luteus 21(26%), Moraxella species 16(20%), Coagulase negative staphylococcus 8(10%), Bacillus species 5(7%), Bicillus circulans 3(5%), Acinetobacter lwoffii 2(2%), and 1 other Candida parapsilosis (1%) a number of bacteria and fungus, was detected. In a disinfectant experiment using LuciPac Pen on the Lumitester PD-30s, we cultured the rubber part of the probe two to three times to measure the bacteria. Bacteria decreased to 97% with Aquanax (alkaline reduced water 100%), 99% with Klarion wash (0.01% sodium hydroxide), 94% with Klarion disinfection (0.01% nitrous acid water), Sterilization was best with Klarion wash (0.01% sodium hydroxide). Therefore, guidelines for cleaning and disinfection of ultrasonic probes was required, and further development of probe-only disinfectants is required.

Whole-Body counters have been used to evaluate the internal contamination of gamma emitting radionuclides. Among the whole-body counters used in domestic nuclear facilities, Fastscan made by CANBERRA contains 2 NaI(Tl) detectors and is generally used to monitor the primary internal exposure. It has the advantage of achieving MDA even with short time measurements. Accuscan is a bed type, and has good energy resolution because it is composed of HPGe detector. Since the Accuscan with better energy resolution than Fastscan has better able to identify radionuclides, it is used to monitor secondary internal exposure. Some nuclear facilities have only Fastscan. We analyzed statistically whether Fastscan is enough to ensure accuracy and precision comparing with Accuscan. To do this, we prepared a CRM created by the Korea Research Institute of Standards and Science. We also obtained the data of 6 Fastscans and 5 Accuscans in domestic nuclear facilities. As a result of the study, although Fastscan compared with Accuscan is not as accurate as the Accuscan, the precision is statistically same. However, accuracy of Fastscan is in compliance with international standards except low energy range. In terms of accuracy and precision except radionuclides emitting low energy, it is possible to measure radioactivity inside workers even in nuclear facilities where only Fastscan is used.

We aim to evaluate safety of radiation by measuring leakage dose and patient(phantom) incident dose of ZEN-PX II dental portable equipment developed by G company. Measurement for leakage dose of equipment is conducted on the top, at the bottom, on the left, on the right and at the back. Dose measurement incident on the subject with the area dosimeter when using the phantom and measurement the leakage dose of equipment when using the phantom are evaluated. Comparing the right with the highest leakage dose as a 0 cm, 25 cm, 50 cm, 75 cm and 100 cm dose measurement at the measurement height of 100 cm, 64.2 uR was reduced to 47.3 uR in the senser mode 0.32sec. Even in film mode it was measured at 414.4 uR and about 27% lower at 162.6 uR. As the result of this study, when the irradiation time is 2 sec the right side dose is 290.5 uR and sensor mode is 0.32 sec the right side dose is 64.2 uR.

During last a decade, there has been increased demand for 3D-printed medical devices with significant improvement of 3D-Printer (also known as Additive. Manufacturing AM), which depend upon human body features. Especially, demand for personalized medical material is highly growing with being super-aged society. In this study, 3D-reconstructed 3D mesh image from CT/MRI-images is demonstrated to analyse each patients' personalized anatomical features by using in house, then to be able to manufacture its counterpart. Developed software is distributed free of charge, letting various researcher identify biological feature for each areas.

The purpose of this study was to compare image quality of indirect digital radiography (IDR) system using the International Electro-technical Commission standard (IEC 62220-1), and to suggest the analysis of noise power spectrum (NPS) which were applied to IEC 62220-1 in medical imaging. In this study, Pixium 4600 (Trixell, France) which is indirect flat panel detector (FPD) was used. The size of image receptor (IR) is $7{\times}17$ inch (matrix $3001{\times}3001$) which performed 14bit processing and pixel pitch is $143{\mu}m$. In IEC standard, NPS evaluation were applied to RQA3, RQA5, RQA7 and RQA9. Because of different radiation quality, each region of interesting (ROI) were compared. The results of NPS indicated up to $3.5mm^{-1}$ including low Nyquist frequency. RQA5 indicated the lowest NPS and the others indicated higher NPS results relatively. NPS result of ROI a38 was higher than ROI a92 and this result indicated that there are more noise in left (cathode) than right (anode). This study were to evaluate NPS by using different radiation quality and setting the each ROI, and to suggest the quantitative methods of measuring NPS.

Morphological information such as shape and margin of micro lesion is important information for diagnosis of disease in clinical imaging. In this study, we investigated the morphological changes of the micro lesions by comparing the contrast and area in grid suppressed DR images according to grid frequency. In the profile analysis of the image, the mass showed an average intensity variation of 8.6 ~ 72.4 after suppression, The higher the grid frequency, the more the contrast was increased. However, in the images obtained using 103 lp / inch, which is a grid frequency less than the sampling frequency, the contrast of the mass in the vertical direction decreased after suppression. In the binary image, the area change of the mass was also large. As a result, the shape, size, and margin of the mass changed. In the case of very small calcification, the higher the grid frequency is the larger the change in contrast, so that a clear image can be obtained in the post-suppression image. However, we could confirm that the margin of the lesion was blurred and the lesion was lost in some of the images using the 103 lp / inch grid. The higher the frequency of the grid, The change of the contrast of fiber occurred largely and clear boundary was confirmed. The decrease of the number of pixels was small and morphological change was small. In conclusion, when using a grid frequency that is not suitable for the sample frequency, morphological changes or lesion loss of micro lesions in the post- suppression image may give the possibility of misdiagnosis in diagnosis and differentiation of the image.

Oogenesis process of ovary produces a lot of undifferentiated cells. Especially, the radiation exposure of early immature cells in the process of growth to oocyte causes serious disabilities. This study examined the radiation damage mechanism of undifferentiated cells and organelles in oogenesis process, and the radioprotection after injection of alliin. The ultrastructure after 7Gy X-ray irradiation on the white rat was observed in the experiment. The results is as follows. It was observed that the nucleus membrane of an oogonium was damaged and vacuolated in the several parts after 15 days of irradiation. The damage of mitochondria membrane and flow in cytoplasm after 20 and 30 days was found in the oogonium. After 40 days observation, peroxidation of fat droplets was found and organelles were tangled each other in ovary tissue. The partial damage of nuclear membrane in oogonium past 15 days after injection of alliin was found, but decreased remarkably. Mitochondria, Golgi body, and rough endoplasmic reticulum were also clearly observed, therefore, radioprotection effects in alliin was confirmed partially.

Radiologic technologists working at the second and third medical institutions are classified as radiation-related workers and radiation workers according to their working departments, and are subject to double regulation by the Ministry of Health and Welfare and the Nuclear Safety Commission. We will try to understand the system of dualization and to understand the investigation of recognition. The dualized system of radiation-related workers and radiation workers includes the difference in name and terminology, the effective dose limit, the maintenance education and training of radiologic technologists, the period of medical examination, the radiation zone, dose of the woman whose pregnancy is confirmed in radiologic technologists, the qualification criteria of the safety officer, and the period of the regular inspection of the radiological equipment. In the questionnaire survey on the dualization system, there were various items showing significant differences between the radiation-related workers and radiation workers Overall, the radiation workers were more aware of the radiation workers' education and related terms than the radiation-related workers.

The purpose of this study was to analyze questionnaires of 161 college students attending radiology departments in order to investigate the actual condition of internet use of radiology students. As a result, 95% of college students using the Internet showed 5.8% of general knowledge, 56.9% of radiation major, and 45.8% of general education. In the field of Internet use, basic medicine was 71.2%, anatomy 59.5% and physiology 51.6%. Radiation theory was 39.9% in radiation physics, 31.4% in radiation biology, and 18.3% in radiation management. The radiological applications were followed by radiography and radiography in order of 31.4% and 20.3%, respectively. The radiological imaging was 45.8%, MRI was 37.9%, CT was 37.3%, ultrasound was 24.2%, And radiation nuclear medicine 25.5%. The results of the descriptive statistics of the satisfaction of the contents using the Internet media showed that the overall satisfaction was below 2.5 Based on the results of this study, it is necessary to develop a program with high accessibility to provide various opportunities for internet-based opportunities to increase the academic achievement value of major subjects through the internet and to solve the difficulties in the major subject.

The diagnostic radiation equipment is managed in accordance with the "Rules for Safety Management of Diagnostic Radiation Equipment" enacted in 1995. The equipments should be inspected before use and every three years after use in accordance with the [Appendix 1] of the same rule. The inspection standard has been maintained without particular revision since enacted. But, over the past two decades new types of equipments have been manufactured and used. So, it is necessary to revise [Appendix 1] by making inspection items and inspection standards. In this study, we revised the classification system of equipments and reviewed international standards of IEC 60601 series, IEC 61223 series and AAPM TG 18 On-line Report No.03. And identified the problem of current inspection standards. Through this, we revised, deleted and added the inspection items and inspection standard of each equipment to meet the domestic circumstances. As a result of the study, we reorganized the classification system of equipment which are current classified as 5 classes into 22 classes as X-ray system etc. (7 classes), CT system etc. (5 classes) and Dental X-ray system etc. (10 classes). And then, we developed 70 inspection items for 6 types of equipments according to the reorganized classification system of equipments. The inspection items and inspection standards derived from this study have been proposed to the KCDC and will be applied to the revision of the Rule's [Appendix 1]. Therefore, we expect to be used as reference materials for domestic medical center, inspection institutions, and equipment manufacturing import companies.

VCP (Vocal Cord Paralysis) is rare but one of most serious complications related to endotracheal intubation. This report is a clinical experience of radiography and laryngeal EMG (Electromyography) assessment for the VCP. A 50-year-old woman with hoarseness, which was occurred after urethral diverticulum excision was examined by laryngoscopy. As a result of laryngoscopy, VCP was observed in left side of her vocal cord, and then recurrent laryngeal nerve damage was detected with additional CT (Computed tomography) scan and laryngeal EMG. After that, the vocal cord movement was recovered as normal state with regular conservative treatment for the 6 months.