• Proceedings of the KSMRM Conference
• /
• 1996.10a
• /
• pp.11-11
• /
• 1996

• Journal of The Korean Radiological Technologist Association
• /
• v.29 no.1
• /
• pp.199-199
• /
• 2003

• Journal of The Korean Radiological Technologist Association
• /
• v.29 no.1
• /
• pp.282-282
• /
• 2003

• Journal of the Korean Society of Radiology
• /
• v.13 no.5
• /
• pp.749-755
• /
• 2019

In this study, we investigated the effects of tube voltage (kVp) and tube current (mAs) on an exposure index (EI) applied to a digital radiography. There used an inverter type digital X-ray generator and an image receptor (IR) utilized a portable wireless detector without a grid. Radiographic images were acquired using a cone pyramid phantom produced using a 3D printer. The X-ray tube voltage was increased from 40 kVp to 120 kVp with 10 kVp increment, and the tube current was increased from 1 mAs to 128 mAs with the twice increment. As a result, kVp had logarithmic relationship with the EI as high $R^2$ value, and mAs had a very high linear relationship too. Also, there was a high correlation between the area dose and the EI of the IR, with the $R^2$ value being 0.76 or more. In conclusion, it had showed that mAs affected the EI linearly, and that it could be advantageous to adjust the easy-to-predict mAs to maintain proper image qualities.

• Journal of radiological science and technology
• /
• v.34 no.3
• /
• pp.215-219
• /
• 2011

Monte Carlo simulation was performed to investigate optimal system of proton computed tomography and to avoid the errors by using data from X ray computed tomography in proton therapy. The informations from two DSSDs to measure position and LYSO scintillation detector to measure the residual energy of proton particle in GEANT4 were used for reconstruction computed tomography.

• The Journal of Korean Society for Radiation Therapy
• /
• v.26 no.2
• /
• pp.199-206
• /
• 2014

Purpose : According to the rapid increase recently in image-guided radiation therapy, It is necessary to control of the image guidance system completely. In particular for the main subject to the accuracy of image guided radiation therapy device to be done essentially the quality assurance. We made efficient phantom in AMC for the management of the accurate and efficient. Materials and Methods : By setting up of five very important as a quality assurance inventory of the Image guidance system, we made (AMC G-Box) phantom for quality assurance efficient and accurate. Quality assurance list were the Iso-center align, the real measurement, the center align of four direction, the accuracy of table movement and the reproducibility of Hounsfield Unit. The rectangular phantom; acrylic with a thickness of 1 cm to $10cm{\time}10cm{\time}10cm$ was inserted the three materials with different densities respectively for measure the CBCT HU. The phantom was to perform a check of consistency centered by creating a marker that indicates the position of the center fixed. By performing the quality assurance using the phantom of existing, comparing the resulting value to the different resulting value using the AMC G-Box, experiment was analyzed time and problems. Therapy equipment was used Varian device. It was measured twice at 1-week intervals. Results : When implemented quality assurance of an image guidance system using AMC G-Box and a phantom existing has been completed, the quality assurance result is similar in $0.2mm{\pm}0.1$. In the case of the conventional method, it was 45 minutes at 30 minutes. When using AMC G-Box, it takes 20 minutes 15 minutes, and declined to 50% of the time. Conclusion : The consistency and accurate of image guidance system tend to decline using device. Therefore, We need to perform thoroughly on the quality assurance related. It needs to be checked daily to consistency check especially. When using the AMC G-Box, It is possible to enhance the accuracy of the patient care and equipment efficiently performing accurate quality assurance.

• The Journal of the Korea Contents Association
• /
• v.16 no.1
• /
• pp.75-81
• /
• 2016

The recent radiation therapy field can provide treatment which guarantees a high degree of accuracy, due to patient set-up using various image guided radiation therapy(IGRT) instruments. But the additional absorbed dose to patient's normal tissues is increasing. Therefore, this study measured the absorbed dose to surrounding normal tissues which is caused by patient set-up using OBI, CBCT, ExacTrac, among various IGRT instruments. The absorbed dose to the head, the chest, the abdomen, and the pelvis from CBCT was 12.57 mGy, 20.82 mGy, 82.93 mGy, and 52.70 mGy, respectively. Also, the absorbed dose from OBI and ExacTrac ranged from 0.76 to 8.58 mGy and from 0.14 to 0.63 mGy, respectively. As a result, CBCT's absorbed dose was far higher than other instruments. CBCT's surface dose was far higher than others, too, but OBI's entrance skin dose was almost the same as CBCT's.

• Journal of the Korean Society of Radiology
• /
• v.12 no.5
• /
• pp.683-692
• /
• 2018

Mammography using mammography equipment is a method of examination that is being employed most widely to diagnose the early stages of breast cancer. Detecting or diagnosing a fibrous tissue, micro calcification, or mass in the breast is influenced by the quality management of mammography equipment considerably. Particularly in mammography, quality management refers to a behavior of figuring out and correcting all sorts of hindrance factors that can cause all the problems related to the equipment associated with the diminishment of diagnosed area due to the reduction of image quality in clinical imaging in advance and maintaining a consistent level of image quality and obtaining a proper image. Here, these researchers aim to summarize and report the general contents of quality management in mammography using mammography equipment.

• The Journal of Korean Society for Radiation Therapy
• /
• v.22 no.1
• /
• pp.1-10
• /
• 2010

Purpose: The effect of artifact was analyzed, which occurs from fiducial marker during the liver Image Guided Radiation Therapy (IGRT) using the fiducial marker. Materials and Methods: The size of artifact of fixed fiducial marker and length of mobile fiducial marker locus were measured using the On-Board Imager system (OBI) and CT simulator, and 2D-2D matching and 3D-3D matching were carried out, respectively, and at this time, the coordinates transition value of couch was analyzed. Results: The measurement of fixed fiducial marker artifact size indicated CT 4.90, 8.10, 12.90, 19.70 mm and OBI 5.60, 10.60, 14.70, 29.40 mm based on the reference CT slice thickness of 1.25, 2.50, 5.00, and 10.00 mm. Meanwhile, the measurement of mobile fiducial marker locus length indicated CT 42.00, 43.10, 46.50 mm, and OBI 43.40, 46.00, 49.30 mm. The coordinates transition of 1.00, 2.00, and 8.00 mm occurred between 2D-2D matching and 3D-3D matching. Conclusion: It was confirmed that the therapy error increased during IGRT due to the influence of artifact when CT slice thickness increased. Thus, it may be desirable to acquire the image less than 2.50 mm in slice thickness when IGRT is implemented using the fiducial marker.

• Radiation Oncology Journal
• /
• v.26 no.2
• /
• pp.118-125
• /
• 2008

Purpose: On-line image guided radiation therapy(on-line IGRT) and(kV X-ray images or cone beam CT images) were obtained by an on-board imager(OBI) and cone beam CT(CBCT), respectively. The images were then compared with simulated images to evaluate the patient's setup and correct for deviations. The setup deviations between the simulated images(kV or CBCT images), were computed from 2D/2D match or 3D/3D match programs, respectively. We then investigated the correctness of the calculated deviations. Materials and Methods: After the simulation and treatment planning for the RANDO phantom, the phantom was positioned on the treatment table. The phantom setup process was performed with side wall lasers which standardized treatment setup of the phantom with the simulated images, after the establishment of tolerance limits for laser line thickness. After a known translation or rotation angle was applied to the phantom, the kV X-ray images and CBCT images were obtained. Next, 2D/2D match and 3D/3D match with simulation CT images were taken. Lastly, the results were analyzed for accuracy of positional correction. Results: In the case of the 2D/2D match using kV X-ray and simulation images, a setup correction within $0.06^{\circ}$ for rotation only, 1.8 mm for translation only, and 2.1 mm and $0.3^{\circ}$ for both rotation and translation, respectively, was possible. As for the 3D/3D match using CBCT images, a correction within $0.03^{\circ}$ for rotation only, 0.16 mm for translation only, and 1.5 mm for translation and $0.0^{\circ}$ for rotation, respectively, was possible. Conclusion: The use of OBI or CBCT for the on-line IGRT provides the ability to exactly reproduce the simulated images in the setup of a patient in the treatment room. The fast detection and correction of a patient's positional error is possible in two dimensions via kV X-ray images from OBI and in three dimensions via CBCT with a higher accuracy. Consequently, the on-line IGRT represents a promising and reliable treatment procedure.