• 대한방사선기술학회지:방사선기술과학
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• 제21권2호
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• pp.26-30
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• 1998

We tried to study in order to furnish the data for medical exposure dose and scattered ray in radiography. As the tables(from 1 to 3) show, we can presume, by means of a concrete numerical value, the amount of results affected by patient radiation exposure dose and somatic effect in radiography. However, there are many difficulties in the difference of exposure factor in each hospital, the accuracy of measuring by tracebility, shortage of exposure dose data especially in the area of children, and portable radiography, etc. In the radiation examination, it is considered if the gained benefit to the patient due to radiation is more than the risk of radiation, then the medical exposure is thought to be justified. Therefore, the radiotechnologists should continually make an effort to develop and study new techniques so as to reduce patient exposure dose.

• 대한방사선기술학회지:방사선기술과학
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• 제46권6호
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• pp.501-508
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• 2023

This study used a adult absorption dose phantom (CIRS model 701-G, USA) made of human equivalent material and the vascular imaging equipment Allura Xper FD 20 (Philips, Netherlands). Optically stimulated luminescent dosimeters (OSLD) were inserted into the anatomical positions corresponding to each organ, and the exposure dose was measured. Dose area product (DAP) and air kerma (AK) measured by the dose meter in the equipment were compared. Continuous imaging was performed at two angles for a total of 20 minutes, with a frame per seconds of 3.75 and 7.5 fps and an FOV of 42 cm, 37 cm, and 31 cm, respectively, under the conditions of fluoflavor I, II, and III, each selected for 5 repetitions. This study was found that selecting a lower fps was the most effective way to reduce patient exposure dose, and adjusting the fluoflavor was a good alternative method for reducing patient exposure dose at high fps. Therefore the method of condition change with the greatest dose reduction effect is to set the minimum FPS and can reduce patient exposure dose according to geometric conditions and fluoflavor characteristics.

• Nuclear Medicine and Molecular Imaging
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• 제43권4호
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• pp.259-279
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• 2009

Radioiodine ablation therapy has been considered to be a standard treatment for patient with differentiated thyroid cancer after total thyroidectomy. Patients may need to be hospitalized to reduce radiation exposure of other people and relatives from radioactive patients receiving radioiodine therapy. Medical staffs, nursing staffs and technologists sometimes hesitate to contact patients in radioiodine therapy ward. The purpose of this paper is to introduce radiation dosimetry, estimate radiation dose from patients and emphasize the safety of radiation exposure from patients treated with high dose radioiodine in therapy ward. The major component of radiation dose from patient is external exposure. However external radiation dose from these patients treated with typical therapeutic dose of 4 to 8 GBq have a very low risk of cancer induction compared with other various risks occurring in daily life. The typical annual radiation dose without shielding received by patient is estimated to be 5 to 10 mSv, which is comparable with 100 to 200 times effective dose received by chest PA examination. Therefore, when we should keep in mind the general principle of radiation protection, the risks of radiation exposure from patients are low and the medical personnel are considered to be safe from radiation exposure.

• 디지털산업정보학회논문지
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• 제10권3호
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• pp.41-48
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• 2014

This paper provides the design of system software for the management of radiation dose that is generated by using computerized tomography(CT). Recently, the radiation leakage incident of Japanese nuclear power plant was in the news internationally and there is a growing interest not only in nuclear power plant but in medical radiation exposure. In spite of the fact that currently safety management of radiation is under control only the workers of the radiation involved, now the exposure management of patients have been required. As surgery and inspections using the radiation have increased, this medical radiation exposure is increasing too. But it is a real situation that medical institutions don't know the level of radiation exposure applied to the patient. Therefore, a system for managing the radiation exposure of a patient from the medical institution is required. This paper proposes a design of a software program that manages the radiation exposure of CT which is a typical imaging tool to use the radiation in the medical institution. By check the amount of radiation dose and set the limit of dose, we would be of help to optimize the medical exposure of the patient.

• 대한방사선기술학회지:방사선기술과학
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• 제38권1호
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• pp.1-6
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• 2015

Whole spine scanography(WSS)는 전신에 X선을 조사하는 검사로 치료기간 동안 빈번한 X선 조사가 이루어지는 검사이다. 일반촬영 분야에서는 많은 X선이 전신에 조사되는 검사이다. 따라서 논문에서는 Auto image pasta기법의 디지털 WSS 검사에서 환자의 검사방향에 따른 유효선량과 장기선량을 전산모사를 통하여 평가하였고, 영상에서 척추의 확대도와 각도의 변화를 평가하였다. 전후면 자세에서의 평균 유효선량은 0.069 mSv였고, 후전면 자세에서 평균 유효선량은 0.0361 mSv로 약 2배의 차이를 보였다. 전후면 자세에서 남성의 평균 유효선량은 0.089 mSv, 여성에 대한 평균 유효선량은 0.431 mSv로 나타났고, 후전면 자세에서 남성의 평균 유효선량은 0.050 mSv, 여성에서는 0.026 mSv로 나타났다. 확대율에서는 후전면 자세에서 전후면 자세에 비해 5%정도 확대 되었으나 각도에는 큰 변화를 보이지 않았다. 따라서 임상 환경에서 동일한 검사조건에서 환자의 자세를 변화시키는 것만으로도 환자의 피폭선량을 감소시킬 수 있음을 확인하였다. 특히 WSS와 같이 치료기간 동안 반복되는 검사에서 환자의 피폭선량 최적화를 위하여 검사 프로토콜의 재정립이 필요함을 확인하였다.

• 대한방사선기술학회지:방사선기술과학
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• 제45권1호
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• pp.69-76
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• 2022

This study, the method of reducing the exposure dose by changing the geometrical requirements among the preceding studies and the method of directly wearing a protector on the patient were used to expose the patient. A comparative experiment was conducted on the method of reducing the dose and the most effective method for reducing the exposure dose was investigated. Using the phantom, the dose of the lens, thyroid gland, and gonad gland in the 5 views most used in coronary angiography and intervention accumulated 5 times for 10 seconds at 60~70 kV, 200~250 mA as an automatic controller of the angiography system, and measured by Optically Stimulated Luminescent Dosimeter(OSLD). SID 100 cm and Cine 15 f/s as a control group the experiment was conducted by dividing the experimental group into 3 groups: a group lowered to Cine 7.5 f/s, a phantom protector, and a group lowered to 95 cm SID. As a result of the experiment, showing decrease in exposure dose compared to the control group. Lowering the cine frame may be the simplest and most effective method to reduce the exposure dose, but there is a limit that it cannot be applied if the operator judges that the diagnostic value is small or feels uncomfortable with the procedure. Conclusion as fallow reducing the exposure dose by directly wearing protector is the next best solution, and it is hoped that the conclusions obtained through this study will help reduce the exposure dose to unnecessary organ.

• 대한방사선기술학회지:방사선기술과학
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• 제44권6호
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• pp.599-605
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• 2021

The International Electrotechnical Commission (IEC) 62494-1 has defined the exposure index (EI) that have a proportional relationship with the dose incident on the image receptor, and target exposure index (EI_T), deviation index (DI). In this study, an appropriate EI_T for skull radiography was established through the diagnostic reference level (DRL) and changes in DI were confirmed. Entrance surface dose (ESD) and EI were obtained using the computed radiography system displayed the EI as per IEC on console and skull phantom by experiment based on the national average exposure conditions announced in 2012 and 2019. And appropriate EI_T was established by applying the DRL in 2012 and 2019. As a results, the EI_T is changed according to the change in the DRL, and the exposure condition that becomes the ideal DI according to the change in the EI_T also has a difference of about 1.41 times. DRL is recommended to optimize the patient dose, however it is difficult to measure in real time at medical institutions whereas EI and DI are displayed on the console at the same time as exposure. When the EI_T is set based on the DRL and the DI is closed to an ideal value, it is useful as a patient dose management tool. Therefore, when the EI_T is periodically managed along with the revision of the DRLs, the patient dose can be optimized through the EI, EI_T and DI.

• 한국방사선학회논문지
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• 제9권2호
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• pp.109-115
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• 2015

전산화단층촬영장치(computed tomography, CT)을 이용한 검사의 경우 방사선량의 분포가 일반 X선 장치와 차이가 있고 검사로 인한 방사선 피폭이 많은 것으로 알려져 있다. 그러나 검사 결과의 정확성에 대한 신뢰도가 높아 그 이용도는 계속적으로 증가하고 있다. 이와 같은 상황을 고려하여 기존에 발표된 자료를 바탕으로 CT장치, CT검사에서 방사선량, 진단참고준위 그리고 검사 시 방사선량 감소 방안에 대해 알아보았다.

• 대한방사선기술학회지:방사선기술과학
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• 제46권2호
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• pp.99-106
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• 2023

The height of the table should be considered important during computed tomography (CT) examination, but according to previous studies, not all radiology technologists set the table at the patient's center at the examination, which affects the exposure dose and image quality received by the patient. Therefore, this study intends to study the image quality exposure dose according to the height of the table to realize the optimal image quality and dose during the brain CT scan. The head phantom images were acquired using Philips Brilliance iCT 256. When the image was acquired, the table height was adjusted to 815, 865, 915, 965, 1015, and 1030 mm, respectively, and each scan was performed 3 times for each height. For the exposure dose measurement, optically stimulated luminescence dosimeter (OSLD) was attached to the front, side, eye, and thyroid gland of the head phantom. In the signal to noise ratio (SNR) measurement result, The SNR values for each table height were all lower than 915 mm. As a result of exposure dose, the exposure dose on each area increased as the table height decreased. The height of the table has a close relationship with the patient's radiation exposure dose in the CT scan.

• 대한디지털의료영상학회논문지
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• 제9권2호
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• pp.23-30
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• 2007

This study attempts to propose an appropriate method of using digital medical imaging equipments, by studying the effects of automatic exposure control(AEC), grid ratio and the change of radiography distance on the patient dose and detertor acquisition dose during the procedure of acquiring image through a digital medical imaging detector. The change of dose following the change of grid ratio's exposure and radiography distance was measured, by using an abdominal phantom organized with tissue equivalent materials in an amorphous silicon thin film transistor detecter installed with AWC. The case to use grid ratio 12 : 1, focal distance 180cm to radiography distance 110cm in AEC, the patient dose increased rather when we used grid ration 10 : 1, focal distance 110cm. When AEC was not used,the dose necessary for image acquisition decreased as the grid ratio became higher and the distance became further. but detector acquisition dose was not reduced when in applied AEC. When purchasing digiral medical imaging equipments, optional items such as AEC and grid shall be accurately selected to satisfy the use of the equipments. Radiography error made by radiation technologist and unnenessary patient dose can be reduced by selecting equipments with a radiography distance marker equipment when it did not apply AEC. These equipments can also be helpful in maintaining high imaging quality, one of the merits of digital detectors.