Earticle

This study aimed at minimizing secondary radiation exposure of the crystalline lens during the computed tomography to medical staff who help unconscious emergency patients. In particular, the radiation high-sensitivity crystalline lens should maintain a effectiveness dose limit of 150 mSv/y. Therefore, adequate shielding is required for the protection of the crystalline lens by secondary radiation. In this study, acrylic plates were used to shield secondary radiation. The focus was on the secondary radiation from the gantry region of the computed tomography. because the position of the assistants matches the gantry portion. The radiation dose rate was measured by increasing the thickness on the acrylic plate. As a result, the secondary radiation dose could not be rapidly shielded as the thickness of the acrylic plate increased. However, the secondary radiation dose of 5-20% decreased with increasing acrylic plate thickness.

In the present, external environmental factors affect human health. In particular, the most important issue is fine dust in these days. Because fine dust is inhaled through the human respiratory system is known to be harmful to health. Tunnels for cars and people can also be easily seen around us. This study, the amount of scattering radiation was measured for walkable tunnels about dust. For the measurement method, dust and radiation dose in the tunnel were measured on good weather (fine dust level: 0~30 μg/m3) and normal day (fine dust level: 0~80 μg/m3). The measurement resulted in an increase of 10~20% of dust in the center of the tunnel on a good weather day and an increase of 20~30% of dust in the center of the tunnel on normal weather. On the other hand, the results of tunnel measurement of radiation dose increased by 10~20% at the center of the tunnel non-depending on the weather. In conclusion, you should pay attention to dust and scattering radiation while walking in the tunnel and be sure to wear respiratory protection when working inside the tunnel for a long time.

This study has purpose to evaluate availability, Sequence and Volume axial, through comparing efficient dose and image quality from the devices in Coronary CT Angiography. We selected 100 patients classified into two groups, Sequence and Volume axial group. We analyzed patient dose and image quality. SNR of Sequence is 22.55% in RCA higher than Volume axial. SNR of Volume axial 22.39% in AA, 18.38% in LV higher than Sequence.(p>0.05) CNR of Volume axial is 23.20% in AA, 24.64% in LV, 15.52% in RCA higher than Sequence.(p>0.05) CTDIVOL of sequence is 15.81% lower(p>0.05), DLP is 35.61% lower than in Volume axial(p<0.05). Sequence is used with 40% lower contrast media than Volume axial, however, there is not significant difference in CNR. In DLP, which is the indicator of patient dose, was also low. Sequence has benefits of patient dose and the amount of contrast media, on the other hand, has a difficulty for breathing noncooperation of patients in clinical situation. In this situation, short scan time of Volume axial can be a benefit for prevention of repeat-exam and motion artifact. Therefore, it is considered that technician's selection of devices, Sequence and Volume axial, taking account of diverse clinical situation is important to maximize efficiency for devices.

The purpose of this study is intended for the comparative analysis of the differences of image on two method by means of quantitative and qualitative evaluation, in testing with the method of Cone Beam using by radiation oncology and that of Conventional. The material of this study are the data of AAPM Phantom and those of established patients, using both CB CT and Conventional CT for imaging-acquisition. Quantitative analysis get significant results.(p>0.05) Qualitative analysis don’t get significant results.(p<0.05) The CT Number, Noise and Resolution conducting on the CB CT falls compared to Conventional CT only but, It is suitable to determine the degree of change in location and size of the tumor without problem.

Computed tomography (CT) scans use contrast medium to help diagnose diseases of vascular and lesions in human organ tissues. The use of tube voltages higher than 120 kV during CT scans improves the transmission of radiation, which increases the diagnostic quality of medical images. However, the use of high tube voltages results in over radiation exposures. In addition, the use of contrast medium may be toxic to the kidneys, which may cause side effects. Therefore, this study attempted to acquire images by changing tube voltage and tube current according to the concentration of contrast medium. also, the aim of this study is to find a way to reduce the exposure dose through image quality evaluation of acquired images. In conclusion, the radiation dose reduction of about 3mGy (about 32%) could be expected by using condition 100kV and 200mAs during abdominal aortic CT scan by contrast medium.