• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.351-357
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• 2023

This Study Rreceived Subjective Evaluation ROC Evaluation from five projection. of projection. at a University Hospital to Obtain and Diagnose Sharp images of apophyseal joints and Vertral arch of Thoracic vertebrae from thoracic X-ray projection. In the Subjective evaluation, the highest Score was obtained by raising the phantom from Supine to LAO by 70° and scoring 20 points at 5° with the X-ray Tube facing the head. In addition, he scored the highest score of 19 points at 8° with the Prone Phantom standing 60° with RAO and the X-ray Tube facing the head. For Objective Evaluation, the Signal-to-noise ratio, was calculated. ROI was set at 1,564 mm2 to obtain the image signal average value (Mean value) and the Standard deviation (SD value). Objective Evaluation The signal-to-noise ratio, was the highest at 5° toward the head in the LPO 70° position of the phantom in the lying position of the Thoracic spine projection, and the Thoracic Spine was the highest at 8° toward the head of the RAO posture of 5,645.

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.4
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• pp.165-169
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• 2011

The purpose of this study is to compare the measurement result of radiation dose by using standard thoracic phantom and ionization chamber to advice proposal in the shooting condition of chest PA projection at hospitals recently. And to understand the change between radiation dose and resolution in different conditions. The period this study was from August 2010 to September 2010 and the subjects of the study was 3 general hospitals, 4 personal hospitals and 1 laboratory at the college. Finally we study with 6 DR, 1 CR, and 4 F/S equipments. Most hospitals met advice proposal, but some of the hospitals exceed advice dose from the result of our study. We can lower radiation dose about 25% when kVp is lowered about 20% in DR equipment. And we can lower radiation dose about 50% when mAs is lowered about 35%. The image quality was similar to the original in the study. Most hospitals which exceed advice dose were personal hospitals. The reason why it happened is that radiation dose for chest PA projection at personal hospitals is higher than general hospitals and the personal hospitals' equipments are older than general hospitals' equipments. We guess that patients' radiation dose of chest PA projection can be lowered from the result.

• Journal of Convergence for Information Technology
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• v.11 no.7
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• pp.189-194
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• 2021

The purpose of this study was to investigate the effect of reducing noise and streaking artefacts by applying the Boost3D algorithm in the case of noise and streaking artifacts generated during computed tomography of the shoulder joint. A phantom study using a thoracic phantom including shoulder joint and clinical evaluation were conducted through shoulder joint images of 35 patients who underwent computed tomography of the shoulder joint from September 2020 to October 2020. The evaluation was divided into groups before and after the application of the Boost3D algorithm, and the noise values, signal to noise ratio, and mean to standard deviation ratio values were analyzed. Both noise values and mean to standard deviation ratio values analyzed in phantom image evaluation and clinical image evaluation were statistically significantly lower in the group after Boost3D was applied (p<0.05). Through this study, it was found that noise and streak artifacts were reduced through the application of Boost3D, and the mean to standard deviation ratio was high, which can be judged as an excellent image. If the Boost3D algorithm is used for computed tomography of the shoulder joint, it is thought that excellent images can be obtained with reduced noise and streaking artifacts that may occur in the shoulder joint area.

• The Journal of Korean Society for Radiation Therapy
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• v.20 no.1
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• pp.17-23
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• 2008

Purpose: Cone-beam CT using linear accelerator attached to on-board imager is a image guided therapy equipment. Because it is to check the patient's set-up error, correction, organ and target movement. but imaging dose should be cause of the secondary cancer when taking a image. The aim of this study is investigation of appropriate cone beam CT scan mode to compare and estimate the image quality and skin dose. Materials and Methods: Measurement by Thermoluminescence dosimeter (TLD-100, Harshaw) with using the Rando phantom are placed on each eight sites in seperately H&N, thoracic, abdominal section. each 4 methods of scan modes of are measured the for skin dose in three time. Subsequently, obtained average value. Following image quality QA protocol of equipment manufacturers using the catphan 504 phantom, image quality of each scan mode is compared and analyzed. Results: The results of the measured skin dose are described in here. The skin dose of Head & Neck are measured mode A: 8.96 cGy, mode B: 4.59 cGy, mode C: 3.46 cGy mode D: 1.76 cGy and thoracic mode A: 9.42 cGy, mode B: 4.58 cGy, mode C: 3.65 cGy, mode D: 1.85 cGy, and abdominal mode A: 9.97 cGy, mode B: 5.12 cGy, mode C: 4.03 cGy, mode D: 2.21 cGy. Approximately, dose of mode B are reduced 50%, mode C are reduced 60%, mode D are reduced 80% a point of reference dose of mode A. the results of analyzed HU reproducibility, low contrast resolution, spatial resolution (high contrast resolution), HU uniformity in evaluation item of image quality are within the tolerance value by recommended equipment manufacturer in all scan mode. Conclusion: Maintaining the image quality as well as reducing the image dose are very important in cone beam CT. In the result of this study, we are considered when to take mode A when interested in soft tissue. And we are considered to take mode D when interested in bone scan and we are considered to take mode B, C when standard scan. Increasing secondary cancer risk due to cone beam CT scan should be reduced by low mAs technique.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.118-123
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• 2015

The frequency of diagnostic radiation examinations in medical institutions has recently increased to 220 million cases in 2011, and the annual exposure dose per capita was 1.4 mSv, 51% and 35% respectively, compared to those in 2007. The number of chest radiography was found to be 27.59% of them, the highest frequency of normal radiography. In this study, we developed a shielding device to minimize radiation exposure by shielding areas of the body which are unnecessary for image interpretation, during the chest radiography. And in order to verify its usefulness, we also measured the difference in entrance surface dose (ESD) and the absorbed dose, before and after using the device, by using an international standard pediatric (10 years) phantom and a glass dosimeter. In addition, we calculated the effective dose by using a Monte Carlo simulation-based program (PCXMC 2.0.1) and evaluated the reduction ratio indirectly by comparing lifetime attributable risk of cancer incidence (LAR). When using the protective device, the ESD decreased by 86.36% on average, nasal cavity $0.55{\mu}Sv$ (74.06%), thyroid $1.43{\mu}Sv$ (95.15%), oesophagus $6.35{\mu}Sv$ (78.42%) respectively, and the depth dose decreased by 72.30% on average, the cervical spine(upper spine) $1.23{\mu}Sv$ (89.73%), salivary gland $0.5{\mu}Sv$ (92.31%), oesophagus $3.85{\mu}Sv$ (59.39%), thyroid $2.02{\mu}Sv$ (73.53%), thoracic vertebrae(middle spine) $5.68{\mu}Sv$ (54.01%) respectively, so that we could verify the usefulness of the shielding mechanism. In addition, the effective dose decreased by 11.76% from $8.33{\mu}Sv$ to $7.35{\mu}Sv$ before and after wearing the device, and in LAR assessment, we found that thyroid cancer decreased to male 0.14 people (95.12%) and female 0.77 people (95.16%) per one million 10-year old children, and general cancers decreased to male 0.14 people (11.70%) and female 0.25 people (11.70%). Although diagnostic radiation examinations are necessary for healthcare such as the treatment of diseases, based on the ALARA concept, we should strive to optimize medical radiation by using this shielding device actively in the areas of the body unnecessary for the diagnosis.