Jungsu Kim

Evaluation of radiation doses in patient and medical staff during endoscopic retrograde cholangiopancreatography procedures

The radiation exposure dose must be optimised because the hazard resulting from an interventional radiology procedure is long term depending on the patient. The aim of this study was to measure the radiation doses received by the patients and medical staff during endoscopic retrograde cholangiopancreatography (ERCP) procedures. Data were collected during 126 ERCP procedures, including the dose-area product (DAP), entrance dose (ED), effective dose (E), fluoroscopy time (T) and number of digital radiographs (F). The medical staff members each wore a personal thermoluminescence dosemeter to monitor exposure during ERCP procedures. The mean DAP, ED, E and T were 47.06 Gy cm(2), 196.06 mGy, 8.93 mSv, 7.65 min and 9.21 images, respectively. The mean dose to the staff was 0.175 mSv and that to the assistant was 0.069 mSv. The dose to the medical staff was minimal when appropriate protective measures were used. The large variation in the patient doses must be further investigated.

A comparative assessment of entrance surface doses in analogue and digital radiography during common radiographic examinations

Digital radiography is often performed at a higher dose rate than analogue radiography for image acquisition. The authors measured the Entrance Surface Dose (ESD) of analogue and digital radiography techniques for 14 radiographic examinations from randomly selected medical centres in the central district of Korea. It was that the mean ESD of the digital examinations was 2.84 mGy (range, 0.37-6.38 mGy) and that of the analogue examinations was 1.83 mGy (range, 0.38-4.74 mGy), resulting in a 55.25 % higher ESD for digital technique. Although this survey is not completely representative of Korea, findings of this study indicate a need for closer exposure management in digital radiography to minimise patient dose.

New organ-based tube current modulation method to reduce the radiation dose during computed tomography of the head: evaluation of image quality and radiation dose to the eyes in the phantom study

A new organ-based tube current modulation (NOB-TCM) method was designed with the intent to decrease tube current by 30% over a prescribed 90° radial arc across the anterior aspect of the radiosensitive organ, without increasing tube current in the remaining radial arc. We compared a reference scan and five other dose-reducing methods with regard to effects on dose, practicality, and image quality to determine the most effective method for the reduction of the radiation dose to the eyes during CT examinations of the head. We compared the radiation doses to the eyes and physical image quality in different regions of interest for TCM and shielding scans. Three types of TCM scans were performed: longitudinal TCM, angular TCM, and NOB-TCM. A bismuth sheet and lead goggles were each applied for the shielding scan. Relative to the reference scan, the dose to the eye was reduced to 25.88% with NOB-TCM, 44.53% with lead goggles, and 36.91% with a bismuth shield. Relative to the reference scan, the mean signal-to-noise ratio (SNR) was decreased to 8.02% with NOB-TCM, 28.36% with lead goggles, and 32.95% with the bismuth shield. The SNR of the anterior region of interest was decreased to 11.89% with NOB-TCM and 87.89% with the bismuth shield. The average figure of merit was increased by 11.7% with longitudinal TCM and 13.39% with NOB-TCM, compared with the reference scan. NOB-TCM is a superior solution for head CT, including the orbital area, due to the reduction in radiation exposure without significant loss in image quality.

Real-Time Patient Radiation Dose Monitoring System Used in a Large University Hospital

Radiation dose monitoring in medical imaging examination areas is mandatory for the reduction of patient radiation exposure. Recently, dose monitoring techniques that use digital imaging and communications in medicine (DICOM) dose structured reports (SR) have been introduced. The present paper discusses the setup of a radiation dose monitoring system based on DICOM data from university hospitals in Korea. This system utilizes the radiation dose data-archiving method of standard DICOM dose SR combined with a DICOM modality performed procedure step (MPPS). The analysis of dose data based on a method utilizing DICOM tag information is proposed herein. This method supports the display of dose data from non-dosimeter-attached X-ray equipment. This system tracks data from 62 pieces of equipment to analyze digital radiographic, mammographic, mobile radiographic, CT, PET-CT, angiographic, and fluorographic modalities.

Patient Radiation Exposure Dose Evaluation of Whole Spine Scanography Due to Exposure Direction

Whole spine scanography(WSS)는 관상면과 시상면에 서 척추의 전후방향과 측면방향 굴곡을 진단하는 검사이다. 19세기에는 척추측만증의 진단을 위해 scoliosismeter를 주 로 활용했다. 이후 임상에서는 X선을 이용한 whole spine scenography를 이용하여 척추측만증의 진단과 추적 관찰 을 시행해 왔다. WSS X선 검사는 척추측만증의 진단과 치 료에 있어 사전 진단에서부터 추적 관찰에 이르기까지 여러 단계에서 사용되고 있다. 환자는 척추측만증를 치료하는 과 정에서 수차례에 걸쳐 WSS를 검사하게 된다. 치료 경과에 따라 3년간 척추측만증의 진단과 치료를 하는 과정에서 순 차적으로 22회의 방사선 검사가 이루어지기도 한다. WSS 는 전신에 X선을 조사하는 검사로 치료기간 동안 자주 반복 되는 검사로 다른 일반촬영 X선검사 보다 환자에 대한 방사 선 피폭이 많은 검사이다. 뿐만 아니라 척추측만증의 진단 을 받기 위해 WSS검사를 시행하는 환자의 상당수는 방사선 의 민감도가 높은 소아나 청년층의 환자이다. Journal of Radiological Science and Technology, 38(1), 1-6 eISSN 2384-1168 ISSN 2288-3509 http://dx.doi.org/10.17946/JRST.2015.38.1.01

Evaluation of the Patient Effective Dose in Whole Spine Scanography Based on the Automatic Image Pasting Method for Digital Radiography

Background: Whole spine scanography (WSS) is a radiologic examination that requires whole body X-ray exposure. Consequently, the amount of patient radiation exposure is higher than the radiation dose following routine X-ray examination. Objectives: Several studies have evaluated the patient effective dose (ED) following single exposure film-screen WSS. The objective of this study was to evaluate patient ED during WSS, based on the automatic image pasting method for multiple exposure digital radiography (APMDR). Further, the calculated EDs were compared with the results of previous studies involving single exposure film-screen WSS. Patients and Methods: We evaluated the ED of 50 consecutive patients (M:F = 28:22) who underwent WSS using APMDR. The anterior-posterior (AP) and lateral (LAT) projection EDs were evaluated based on the Monte Carlo simulation. Results: Using APMDR, the mean number of exposures was 6.1 for AP and 6.5 for LAT projections. LAT projections required more exposures (6.55%) than AP projections. The mean ED was 0.6276 mSv (AP) and 0.6716 mSv (LAT). The mean ED for LAT projections was 0.6061 mSv in automatic exposure control (AEC) and 0.7694 mSv in manual mode. The relationship between dose-area-product (DAP) and ED revealed a proportional correlation (AP, R2 = 0.943; LAT, R2 = 0.773). Compared to prior research involving single exposure screen-film WSS, the patient ED following WSS using APMDR was lower on AP than on LAT projections. Conclusion: Despite multiple exposures, ED control is more effective if WSS is performed using APMDR in the AEC mode.

Monte Carlo simulation-based feasibility study of a dose-area product meter built into a collimator for diagnostic X-ray.

According to the International Electro-technical Commission, manufacturers of X-ray equipment should indicate the number of radiation doses to which a patient can be exposed. Dose-area product (DAP) meters are readily available devices that provide dose indices. Collimators are the most commonly employed radiation beam restrictors in X-ray equipment. DAP meters are attached to the lower surface of a collimator. A DAP meter consists of a chamber and electronics. This separation makes it difficult for operators to maintain the accuracy of a DAP meter. Developing a comprehensive system that has a DAP meter in place of a mirror in the collimator would be effective for measuring, recording the dose and maintaining the quality of the DAP meter. This study was conducted through experimental measurements and a simulation. A DAP meter built into a collimator was found to be feasible when its reading was multiplied by a correction factor.