• The Journal of the Korea Contents Association
• /
• v.10 no.3
• /
• pp.266-270
• /
• 2010

In case of the Dental X-ray apparatus, the diameter (or the field size) of the tip of the cone should be less than 7 cm according to the Diagnosis Radiation Equipment Safety Management. However, deviation from the field is not expected to be big as photography is made at close range from the skin. Also, as the size of film or digital detector used in intra-oral photography is $3\times4cm^2$, the size mentioned above can be considered to be much bigger. Furthermore, the patient dose by short-distance photography can not be ignored. Therefore, effect on the patient dose, resolution and image qualty was examined by reducing the cone diameter by 0.5 cm interval. The result showed that the patient dose was reduced and a partial improvement in picture contrast was observed. Therefore, it can be concluded from these results that further investigation may be worthwhile in terms of policy.

• Journal of radiological science and technology
• /
• v.31 no.1
• /
• pp.11-16
• /
• 2008

Purpose : The aim of this study was to predict radiation dose at 1 meter with BMI(body mass index) in thyroid cancer patients treated with radio-iodine and provide the efficient guideline in the management of patients. Methods : 140 patients from thyroidectomy for thyroid cancer were enrolled. All subjects under went 150 mCi radio-iodine therapy and performed whole body scan 1 week later. BMI(weight divided by square of height) was calculated to evaluate the amount of fatty tissue indirectly. The radiation dose at 1 meter was measured initially and on 2nd days. the relation of values with BMI were analyzed statically. As for the method of statistical analysis, using Med calc Version 9,2,2,0 Program. Results : (1) The initial effective dose was inversely correlated with the BMI. Significance level was 0.0004. (2) We obtained the following formula from the data of initial effective dose and BMI: Y = -30.91X + 350.4(${\mu}Sv/h$)(Y: initial radiation dose, x: Group). (3) After 21.55 hours, than radiation dose was less than those recommended by ICRP or NRC in 53% of the population. Conclusion : Using BMI, the initial radiation dose and 2nd days dose can be predicted in thyroid cancer patients before radio-iodine therapy. It may be used for predicting the time of discharge and control the isolation room. We were able to predict the radiation exposure after discharge using this calculated value.

• Journal of the Korean Society of Radiology
• /
• v.12 no.7
• /
• pp.821-826
• /
• 2018

This study was performed randomly from all the patients who visited the University Hospital in Gyeonggi-do from January 1, 2018 to June 30, 2018 for the abdominal CT scan. We divided the patients into three groups and evaluated the extent of effective dose and image quality according to the area of the abdominal CT image. As a result, the effective dose was 7.34 mSv in the average area group, 8.39 mSv in the average area and 5.89 mSv in the average area. For the analysis of image quality, ROI was plotted in the same three regions according to the abdominal area. As a result, CT values were significantly different in the abdominal area classified into 3 groups (p <0.05). The results of this study can be used as a basic data for the development of a protocol that can be applied in actual clinical practice. It is thought that it can help to reduce the image quality and the radiation dose.

• Progress in Medical Physics
• /
• v.17 no.3
• /
• pp.144-152
• /
• 2006

The telemedicine using independent client-server system via networks can provide high quality normalized services to many hospitals, specifically to local/rural area hospitals. This will eventually lead to a decreased medical cost because the centralized institute can handle big computer hardware systems and complicated software systems efficiently and economically, Customized cancer radiation treatment planning for each patient Is very useful for both a patient and a doctor because it makes possible for the most effective treatment with the least possible dose to patient. Radiation planners know that too small a dose to the tumor can result in recurrence of the cancer, while too large a dose to healthy tissue can cause complications or even death. The best solution is to build an accurate planning simulation system to provide better treatment strategies based on each patient's computerized tomography (CT) image. We are developing a web-based and a network-based customized cancer radiation therapy simulation system consisting of four Important computer codes; a CT managing code for preparing the patients target data from their CT image files, a parallel Monte Carlo high-energy beam code (PMCEPT code) for calculating doses against the target generated from the patient CT image, a parallel linear programming code for optimizing the treatment plan, and scientific data visualization code for efficient pre/post evaluation of the results. The whole softwares will run on a high performance Beowulf PC cluster of about 100-200 CPUs. Efficient management of the hardware and software systems is not an easy task for a hospital. Therefore, we integrated our system into the client-sewer system via network or web and provide high quality normalized services to many hospitals. Seamless communication with doctors is maintained via messenger function of the server-client system.

• Journal of the Korean Society of Radiology
• /
• v.9 no.2
• /
• pp.121-124
• /
• 2015

Digital Mammography is very important for the early diagnosis of breast cancer. but excessive radiation dose to the patient may increase the probability of occurrence of breast cancer. absorbed dose rate and signal, noise, and contrast in accordance with the change of the filter, and analyzed the signal-to-noise ratio. absorbed dose rate GE Equipment is higher than that of Siemens and Hologic. using the material of Mo / Mo was lower than the other target-filter combination. SNR of Siemens equipment is high and measured high when Mo / Mo selected, the other two devices was measured high when Mo / Rh selected. when you choose a target-filter combination our results will be a good indicator.

• Journal of the Korea Convergence Society
• /
• v.5 no.1
• /
• pp.17-22
• /
• 2014

During the lateral x-ray testing of lumbar, in order to obtain the optimal image for diagnosis and to minimize the exposure dose, a glass dosimeter and spatial dose measuring meter was used to measure and evaluate the exposure dose and spatial dose distribution of each organs. The exposure dose of the organs have increased as they were closer to the X-ray tube and when the radiation field was completely opened, the exposure dose was increased. In addition, scattered rays have increased as the distance got closer to the subject and with the distance of more than 200cm, 95% of scattered rays was reduced. Such results can anticipate the exposure dose of patients during the lumbar x-ray test in the future and it can be proposed as a data for determining the testing methods and expected to be widely used as an important basic data for reducing the medical exposure dose.

• Progress in Medical Physics
• /
• v.18 no.3
• /
• pp.139-143
• /
• 2007

The purpose of this study was to measure and evaluate radiation dose for MDCT parameters. Patient dose for various combination of MDCT parameters were experimentally measured, using MDCT (GE light speed plus 4 slice, USA), model 2026C electrometer (RADICAL 2026C, USA), standard Polymethylmethacrylate (PMMA) head and body CT dosimetry phantoms. In clinical situations, for a typical abdominal scan performed with MDCT at 120 kVp, 180 mAs, 20 mm collimation, and a pitch of 0.75 $CTDI_w,\;CTDI_{vol}$ were measured as 20.2 mGy, 26.9 mGy, respectively. When scan length is assumed as 271.3 mm, DLP and measured effective dose of the abdominal would be calculated as $729.1\;mGy{\cdot}cm$, 10.9 mSv, respectively.

• Journal of the Korean Society of Radiology
• /
• v.9 no.7
• /
• pp.535-540
• /
• 2015

Collimator has important functions with control primary X-ray that decrease radiation exposure dose for patients and reduce scatter ray and make better quality of image. But there are no regulations for X-ray mammography device of collimator, so widely used device adopt rectangularly controlled collimator. Though digital X-ray mammography device expand supply recently, rectangularly controlled collimator of film/screen mode still used. After searching for real condition of beam field with digital mammography, we made a multi-leaf collimator which is able to adjust the beam field in accordance with size and shape of breast, and we measuring up the transitions of image quality, average glandular dose(AGD) and, Dose area product(DAP). There are no significant differences between rectangularly controlled collimator and multi-leaf collimator, and DAP value decreased by 50.72%. As conclusion, there needs to expand the use of multi-leaf collimator for optimum adoption of beam field in digital mammography, and also need to develop an automatic regulation of beam field for reduce of exposure dose to patients.

• Journal of the Korean Society of Radiology
• /
• v.13 no.5
• /
• pp.683-689
• /
• 2019

We are trying to evaluate usefulness of Wide Coverage Volume Axial Mode by comparing and analyzing for exposure doses to patients and video quality extracted from two materials. First material is a computer tomography scanning of paediatric cardiac made by using High Pitch Mode, which is designed for diagnosing Congenital cardiac diseases. Second material is computer tomography scanning of paediatric cardiac made by using Wide Coverage Volume Axial Mode. When we did computer tomography scanning of paediatric cardiac, we used High Pitch Mode and Wide Coverage Volume Axial Mode to 50 patients of each, overall 100 patients. Also, we compared exposure doses to patients using videos got from each protocol. Then we compared video quality by calculating SNR and CNR by setting ROI of each. Not only exposure doses to patients were reduced by 13.07 %, but also SNR and CNR were improved when testing used Wide Coverage Volume Axial Mode rather than using High Pitch Mode. Wide Coverage Volume Axial Mode reduced testing time by using high-speed scanner. Furthermore, we can find out that Wide Coverage Volume Axial Mode is an useful method through improving video quality and reducing exposure doses to patients than using High Pitch Mode from ASiR-V, which is low-dose technology.

• Journal of radiological science and technology
• /
• v.38 no.4
• /
• pp.347-353
• /
• 2015

The purpose of this study is to suggest proper additional filtration by comparisons patient dose and image quality among additional filters in digital chest tomosynthesis (DTS). We measured the effective dose, dose area product (DAP) by changing thickness of Cu, Al and Ni filter to compare image quality by CD curve and SNR, CNR. Cu, Al and Ni exposure dose were similar thickness 0.3 mm, 3 mm and 0.3 mm respectively. The exposure dose using filter was decreased average about 33.1% than non filter. The DAP value of 0.3 mm Ni were decreased 72.9% compared to non filter and the lowest dose among 3 filter. The effective dose of 0.3 mm Ni were decreased 48% compared to 0.102 mSv effective dose of non filter. At the result of comparison of image quality through CD curve there were similar aspect graph among Cu, Al and Ni. SNR was decreased average 19.07%, CNR was average decreased 18.17% using 3 filters. In conclusion, Ni filtration was considered to be most suitable when considered comprehensive thickness, character, sort of filter, dose reduction and image quality evaluation in DTS.