• Journal of radiological science and technology
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• v.13 no.1
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• pp.53-64
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• 1990

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.343-349
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• 2011

This study was aimed to evaluate the absorbed dose in brain of dental radiography. For radiographic exposure, PLD(photoluminescence dosimetry) chips placed in Rando phantom to measurement the absorbed dose to pituitary gland, orbit, maxillary sinus and submandibular glands, thyroid gland, esophagus. Equipments were used Kodak 2200, Kodak 8000C dental radiographic systems and computed tomography(Lightspeed VCT). The absorbed doses were measured at the same exposure parameters and distance by the clinical factor(kV, mA, sec). The result were as follows ; The absorbed dose for intra-oral radiography were 0.02~2.47cGy, the greatest absorbed dose was 2.47cGy for thyroid gland in maxillary right molar projection. the lowest adsorbed dose was 0.02cGy for submandibular glands in lower anterior projection. The absorbed dose for extra-oral radiography were 0.36~3.44cGy of cephalometric method, 0.14~12.82cGy of panoramic method, 8.17~253.63cGy of computed tomography, the greatest adsorbed dose was 253.63cGy for submandibular glands in maxillary CT scan. the lowest adsorbed dose was 0.14cGy for orbit in panoramic method. As a result, extra-oral radiography was measured more than intra-oral radiography. In particular, method which used computed tomography was measured more than 100 times than intra-oral radiography highly. Therefore, you must show a guideline in extra-oral radiography and an effort to reduce absorbed dose is demanded.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.319-325
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• 2022

The Study In order to obtain a sharpness Image from Skull PA axial projection (Haas) in a head axial X-ray Examination, this study changed the posture angle using Skull Phantom and evaluated the image subjectively to 5 radiologists who worked in the Department of Imaging at University Hospital. In the prone position, the head was lowered 4 cm from the back of the head, entered 25° toward the head, and the image evaluation score was high with 20 points, such as the back bone, dorsum sellae projected in the large hole, and posterior clinoid process. In addition, the score significance was verified, and the Cronbach Alpha value was evaluated to have good reliability of 0.789. As a result of calculating the signal-to-noise ratio (SNR) by setting the region of interest (ROI) of the image, it was the highest at 5.957 for 25° incident at the back of the head and 6.430 for 30° incident at the back of the head. As a result of the study, in order to obtain a sharp image of the back of the head bone, dorsum sellae, and posterior clinoid process when shooting in the axial direction after the head, it is filmed by tilting 25° toward the head from 4 cm below the back of the head. In order to obtain a sharp image of rock pyramid symmetry, petrous ridge, sagittal suture, and lambdoid suture, it is thought that it will be helpful for clinical use if you shoot it 8cm down from the back of the head and tilt it 30° toward the head.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.385-390
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• 2009

The Pneumatic Reduction and VCUG (Voiding Cystourethrography) are commonly used in the paediatric age group. The procedures had a particularly long fluroscopic screening time, despite a successful outcome for paediatric patients. Pneumatic Reduction and VCUG almost invariably requires fluoroscopic guidance which does confer a radiation dose. This article contains suggestions on how the radiation dose to paediatric patients from Pneumatic Reduction and VCUG can be made "as low as reasonably achievable" (ALARA). The aim of our study was eliminated in spot image applying the FluoroGrab, which has function of capturing an image of interest area from the picturing while fluoroscopic procedures. FluoroGrab has clinical value equivalent to the spot image, and is applied to the most recent fluoroscopic procedures. The radiologist and the radiographers should consider new option for decreasing the radiation exposure delivered to paediatric patients by making equipment modifications to the fluoroscopy to optimize radiation exposure reduction techniques. Thus, we propose the FluoroGrab instead of spot exposure for the reduction of patient exposure dose in paediatric, and try to confirm the effect of the mitigating amount of radiation exposure to paediatric patients when pneumatic reduction and VCUG. Fluorograb is the safe and useful method that shows the equivalent level of accuracy to spot exposure, and to minimize the radiation load to paediatric patients are to be the substitute for the spot exposure for Pneumatic Reduction and VCUG.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1167-1172
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• 2009

The Pneumatic Reduction and VCUG (Voiding Cystourethrography) are commonly used in the paediatric age group. The procedures had a particularly long fluroscopic screening time, despite a successful outcome for paediatric patients. Pneumatic Reduction and VCUG almost invariably requires fluoroscopic guidance which does confer a radiation dose. This article contains suggestions on how the radiation dose to paediatric patients from Pneumatic Reduction and VCUG can be made "as low as reasonably achievable" (ALARA). The aim of our study was eliminated in spot image applying the FluoroGrab, which has function of capturing an image of interest area from the picturing while fluoroscopic procedures. FluoroGrab has clinical value equivalent to the spot image, and is applied to the most recent fluoroscopic procedures. The radiologist and the radiographers should consider new option for decreasing the radiation exposure delivered to paediatric patients by making equipment modifications to the fluoroscopy to optimize radiation exposure reduction techniques. Thus, we propose the FluoroGrab instead of spot exposure for the reduction of patient exposure dose in paediatric, and try to confirm the effect of the mitigating amount of radiation exposure to paediatric patients when pneumatic reduction and VCUG. Fluorograb is the safe and useful method that shows the equivalent level of accuracy to spot exposure, and to minimize the radiation load to paediatric patients are to be the substitute for the spot exposure for Pneumatic Reduction and VCUG.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.165-171
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• 2002

Purpose : In order to perform craniospinal irradiation (CSI) in the supine position on patients who are unable to lie in the prone position, a new simulation technique using a CT simulator was developed and its availability was evaluated. Materials and Method : A CT simulator and a 3-D conformal treatment planning system were used to develop CSI in the supine position. The head and neck were immobilized with a thermoplastic mask in the supine position and the entire body was immobilized with a Vac-Loc. A volumetrie image was then obtained using the CT simulator. In order to improve the reproducibility of the patients' setup, datum lines and points were marked on the head and the body. Virtual fluoroscopy was peformed with the removal of visual obstacles such as the treatment table or the immobilization devices. After the virtual simulation, the treatment isocenters of each field were marked on the body and the immobilization devices at the conventional simulation room. Each treatment field was confirmed by comparing the fluoroscopy images with the digitally reconstructed radiography (DRR)/digitally composite radiography (DCR) images from the virtual simulation. The port verification films from the first treatment were also compared with the DRR/DCR images for a geometrical verification. Results : CSI in the supine position was successfully peformed in 9 patients. It required less than 20 minutes to construct the immobilization device and to obtain the whole body volumetric images. This made it possible to not only reduce the patients' inconvenience, but also to eliminate the position change variables during the long conventional simulation process. In addition, by obtaining the CT volumetric image, critical organs, such as the eyeballs and spinal cord, were better defined, and the accuracy of the port designs and shielding was improved. The differences between the DRRs and the portal films were less than 3 mm in the vertebral contour. Conclusion : CSI in the supine position is feasible in patients who cannot lie on prone position, such as pediatric patienta under the age of 4 years, patients with a poor general condition, or patients with a tracheostomy.

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

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.109-115
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• 2015

In case of a CT examinations, there is a difference in the distribution of radiation dose from that of general X-ray equipments, and it has been known to cause a great radiation exposure during the examinations. However, owing to its high reliability on the accuracy of a examinations result, its use has increased continuously. In consideration of such a circumstance, the CT equipment, radiation dose during CT examinations, diagnostic reference level, and solutions to reduce radiation dose were mentioned on the basis of previously reported data.

• Journal of Oral Medicine and Pain
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• v.33 no.2
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• pp.195-204
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• 2008

Osteoarthritis is caused by joint degeneration, a process that includes progressive loss of articular cartilage accompanied by attempted repair of articular cartilage, remodeling and sclerosis of subchondral bone, and osteophyte formation. The most common causative factor that either causes or contributes to osteoarthritis is overloading of the articular structures of the joint. The diagnosis of temporomandibular joint(TMJ) osteoarthritis is based on the patient's history and clinical findings such as limited mandibular opening, crepitation and tenderness to palpation on TMJ. The diagnosis is usually confirmed by TMJ radiographs, which will reveal evidence of structural changes in the subarticular bone of the condyle or fossa. Plain radiography techniques such as panoramic, transcranial, transpharyngeal views can be used in most dental offices for evaluation of the TMJs. However, plain radiographs are often limited due to overlapping and distortion of anatomical structures. The aim of this study was to compare the clinical examination and panoramic view with computed tomography for diagnosis of temporomandibular degenerative joint disease, and to compare the findings of condylar bony changes through panoramic radiography with that of computed tomography, hence, to confirm the limitations of clinical and panoramic radiography, and the validity of the computed tomography for diagnosis of temporomandibular degenerative joint disease. The pathophysiology of the TMJ osteoarthritis remains poorly understood, and current treatments are based more on speculation than science, and symptomatic treatments often fail to provide satisfactory pain relief. For diagnosis of TMJ osteoarthritis, clinical examination and radiographic examination for confirmation of the bony changes are essential, and computed tomography are clearly superior to plain radiographs for their limitations.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.47-54
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• 2021

Purpose : In order to evaluate the usefulness of clinical application of the Pause & Resume methods by comparing and analyzing the data stability and dose reduction effect when repeat scan assuming irregular breathing and using the Pause & Resume method during chest 4D CT using Quasar^TM Phantom. Materials and Methods : Using the Quasar^TM Phantom, set the breathing rate per minute to 15 BPM and 7.5 BPM, and set the S15 point as an irregular breathing section, and then placed OSLD to this point and use the Pause & Resume method to measure the dose of S15. CTDIvol, DLP, and ALARA-CT were used for comparative analysis of radiation dose between Pause & Resume method and Repeat-scan. In order to evaluate the stability and usability of the data applying the Pause & Resume method, the captured images were sorted by Advanced Workstation Volume Share7 and then sent to Eclipse^TM, the diameter and volume were analyzed by forming a contour on the iron ball in the Quasar^TM Phantom Results : When using Pause & Resume, the dose of OSLD measurement increased by 1.97 times in the section of S15. As a result of image evaluation, the average value of all volumes measured with and without the Pause & Resume method at 15 BPM and 7.5 BPM was 15.2 cm3±0.5%.Allthemeasuredvaluesfor the radius of iron ball were 3.1 cm regardless of whether Pause & Resume method was used or not. In the case of using Pause & Resume, 33% decreased from the lowest DLP value and 38% decreased from the highest DLP value of repeat scan, and the effective dose also decreased 32.1% from the minimum value and 37.6% from the maximum value. Conclusion: Irradiation dose was increased by Pause & Resume method because of the repeat scan on the S15 site where assuming irregular breathing occurred, However Pause & Resume method led to a significant reduction in dose on overall scan range. It also proved the usefulness of clinical application of the Pause & Resume method as a result of similar diameters and volumes of iron ball measurement.