• Title/Summary/Keyword: entrance skin dose

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The Relationship of Overdensity to Overexposure Each Film/screen Systems in Chest Radiography (흉부 X선사진 농도로부터 표면선량을 산출하는 방법)

  • Kim, Jung-Min;Joon, Huo;Hayashi, Taro;Ishida, Yuji;Sakurai, Tatsuya
    • Journal of radiological science and technology
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    • v.22 no.1
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    • pp.13-20
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    • 1999
  • This study is to calculate the exposed radiation dose using Bit method, NDD calculation method and monogram method without dosimeter. In addition, we can calculate the radiation dose from x-ray film density as a film badge. The authors examined the entrance skin dose from $2{\sim}3$ intercostal chest x-ray film density. We also studied the relationship between film density and equivalent dose in the each screen film system under the different radiation quality and the poor geometry condition of grid ratio. As results, we established the deductive method to define the entrance skindose from chest x-ray film density. The error range was found in the range $-13%{\sim}+l7%$ for between deductive entrance skindose and the $2{\sim}3$ intercostal chest x-ray film density to actual detective radiation dose with dosimeter.

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Entrance Surface Dose according to Dose Calculation : Head and Wrist (피폭선량 산출을 통한 피부입사선량 계산: 머리 및 손목을 중심으로)

  • Sung, Ho-Jin;Han, Jae-Bok;Song, Jong-Nam;Choi, Nam-Gil
    • Journal of radiological science and technology
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    • v.39 no.3
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    • pp.305-312
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    • 2016
  • This study were compared with the direct measurement and indirect dose methods through various dose calculation in head and wrist. And, the modified equation was proposed considering equipment type, setting conditions, tube voltage, inherent filter, added filter and its accompanied back scatter factor. As a result, it decreased the error of the direct measurement than the existing dose calculation. Accordingly, diagnostic radiography patient dose comparison would become easier and radiogrphic exposure control and evaluation will become more efficient. The study findings are expected to be useful in patients' effective dose rate evaluation and dose reduction.

Calculation Method of Entrance Skin Dose in X-ray Beam Quality Factor (선질계수에 의한 피부입사선량 계산법)

  • Kim, Sung-Chul;Kim, Chong-Yeal;Ahn, Sung-Min
    • The Journal of the Korea Contents Association
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    • v.10 no.2
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    • pp.258-267
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    • 2010
  • This interest in radiation exposure makes increasing doctor's awareness and knowledge of radiation dose in patients during X-ray test important in reducing patient's uneasiness. However, very few facilities are equipped with measurement instruments. Therefore, an intensive study to find out patient dose using computational method has been initiated. This study used special features of the bit system and NDD-M and directly measured the output dose of diagnostic X-ray instruments used in Korea to create tables. Two different methods were found to be adequate when applied to cases when X-ray outputs were both known and unknown, and comparative experiments with real measurement doses were carried out. Presented methods were found to provide more accurate results compared to the bit system and NDD-M. Therefore, patient dose during clinical trials were found to be more easily acceptable to medical personnel in the radiation field in terms of radiation exposure and reduction of medical X ray dose.

Evaluation of Skin Dose of Intensity Modulated Radiation Therapy in Breast Cancer Patients (유방암환자의 세기조절방사선치료에서 피부선량 평가)

  • Kim, Sung-Kyu;Kim, Myung-Se;Yun, Sang-Mo
    • Progress in Medical Physics
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    • v.18 no.3
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    • pp.167-171
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    • 2007
  • In the case of radiotherapy following breast conservation therapy for breast cancer patients, the characteristic of skin dose was investigated in the treatment of intensity modulated radiation therapy (IMRT) for breast cancer patients by comparing and analysing entrance skin dose irradiated during radiotherapy using tangential technique radiotherpy, and IMRT. The calculation dose irradiated to breast skin was compared with TLD measurement dose in treatment planning by performing the two methods of radiotherapy using tangential technique, and IMRT in treatment planning equipment. The skin absorbed dose was measured to pass a nipple by spacing of 1 cm distance from center to edge of body. In the radiotherapy of tangential technique, for the irradiation of 180 cGy to PTV, the calculation dose was ranged from 103.5 cGy to 155.2 cGy, measurement dose was ranged from 107.5 cGy to 156.2 cGy, and skin dose in the center was maximum 1.45 times more irradiated than that in the edge. In the IMRT, for the irradiation of 180 cGy to PTV, the calculation dose was ranged 9.8 cGy at 80.2 cGy, measurement dose was ranged 8.9 cGy at 77.2 cGy, and skin dose in the center was maximum 0.23 times less irradiated than that in the edge. IMRT was more effective for skin radiation risks because radiation dose irradiated to skin in IMRT was much less than that in radiotherapy of tangential field technique.

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The Study on the Reduction of Patient Surface Dose Through the use of Copper Filter in a Digital Chest Radiography (디지털 흉부 촬영에서 구리필터사용에 따른 환자 표면선량 감소효과에 관한 연구)

  • Shin, Soo-In;Kim, Chong-Yeal;Kim, Sung-Chul
    • Journal of radiological science and technology
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    • v.31 no.3
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    • pp.223-228
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    • 2008
  • The most critical point in the medical use of radiation is to minimize the patient's entrance dose while maintaining the diagnostic function. Low-energy photons (long wave X-ray) among diagnostic X-rays are unnecessary because they are mostly absorbed and contribute the increase of patient's entrance dose. The most effective method to eliminate the low-energy photons is to use the filtering plate. The experiments were performed by observing the image quality. The skin entrance dose was 0.3 mmCu (copper) filter. A total of 80 images were prepared as two sets of 40 cuts. In the first set (of 40 cuts), 20 cuts were prepared for the non-filter set and another 20 cuts for the Cu filter of signal + noise image set. In the second set of 40 cuts, 20 cuts were prepared for the non-filter set and another 20 cuts for the Cu filter of non-signal image (noisy image) with random location of diameter 4 mm and 3 mm thickness of acryl disc for ROC signal at the chest phantom. P(S/s) and P(S/n) were calculated and the ROC curve was described in terms of sensitivity and specificity. Accuracy were evaluated after reading by five radiologists. The number of optically observable lesions was counted through ANSI chest phantom and contrast-detail phantom by recommendation of AAPM when non-filter or Cu filter was used, and the skin entrance dose was also measured for both conditions. As the result of the study, when the Cu filter was applied, favorable outcomes were observed on, the ROC Curve was located on the upper left area, sensitivity, accuracy and the number of CD phantom lesions were reasonable. Furthermore, if skin entrance dose was reduced, the use of additional filtration may be required to be considered in many other cases.

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Comparative Study of Radiation Exposure using Entrance Skin Dose Calculation Technique in Diagnostic X-Ray Radiography (입사 표면 선량 계산에 따른 진단용 X-선 촬영시 피폭선량 비교 연구)

  • Han, Jae-Bok;Choi, Nam-Gil;Sung, Ho-Jin
    • The Journal of the Korea Contents Association
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    • v.11 no.12
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    • pp.357-363
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    • 2011
  • The aim of this study is to compare radiation dose in diagnostic X-ray radiography and calculated by different mathematical equation. The result of ESDs direct measurement and that calculated by Mori NDD-M shows the biggest difference. On the other hand, equation by Edmonds shows the lowest difference of ESDs. Also, Rectification due to the difference between direct dose measurement and calculation method commutated three-phase, single phase and inverter type, show less difference in the drive way. In conclusion, this study can be helpful for expecting radiation dose-exposure and control exposure parameters for the diagnostic x-ray radiography.

A Study on Patients Dose and Image Quality according to Source to Image receptor Distance in Abdomen Radiography: comparison of ESD measured and DRLs in other countries (복부일반촬영시 선원과 검출기간의 거리변화에 따른 영상 화질 및 피폭선량에 관한 연구)

  • Jang, Ji-Sung;Choi, Weon-Keun;Jung, Jae-Yon;Lee, Kwan-Sub;Ha, Dong-Yoon
    • Korean Journal of Digital Imaging in Medicine
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    • v.14 no.2
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    • pp.39-46
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    • 2012
  • Purpose : The purpose of this study was to reduce Entrance Surface Dose and maintain image quality by changing Source to Image receptor Distance. And we'd like to compare ESD on this study to DRLs in other contries. Materials and Methods : We used indirect DR system(Definium 8000, General Electric, USA)and phantom(ART-200X, Flukebiomedical, USA),glass dosimeters(GD-352M, Asahi Techno Glass, Japan)for this study. The imagies were obtained throuh 80kVp fixed, and different tube currents using AEC mode in $16{\times}16$(inch) field size and changing Source to Image receptor Distance from 100 cm to 130 cm per 10 cm unit. The phantom with attaching 5 glass dosimeters on abdomonal skin was set at supine and erect position as a anterioposterial projection on detector For measuring Entrance Surface Dose. Image analysis was conducted by histograms of Image J(1.46r) which was given from National Institutes of Health(NIH). Results : Due to inverse square law of distance, the tube currents were increasing 42.6 % in supine position and 32.6 % in erect position according to the change of Source to Image receptor Distance. While Entrance Surface Doses were rapidly decreasing 14.2 % in supine position and 29.4 % in erect position according to the change of Source to Image receptor Distance. As the results of histogram using Image J, pixel mean values from 100 cm to 110 cm, 120 cm and 130 cm were decreasing each 1.4%, 2.5%, 2.7%, 4.5%, 2.2 %, 5.8 % in supine, erect position. While standard deviations from 100 cm to 110 cm, 120 cm and 130 cm were increasing each 1.4 %, 2.5 %, 2.5 %, 4.0 %, 2.0 %, 4.9 % Consequently, there are no significant differences in abdomen images taken. Conclusion: As the results described above, we strongly recommend using long Sourceto Image receptor Distance than 100cm that we have been using. So, we should deliver less Entrance Surface Dose to the patients while maintaining image quality in abdomen radiography.

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A Survey on Patient Dose and Exposure Conditions in Simple Radiography of the Abdomen (복부 단순 X-선 촬영조건과 환자 피폭에 관한 조사 연구)

  • Kim, Sung-Soo;Lee, Sun-Sook;Huh, Joon
    • Journal of radiological science and technology
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    • v.19 no.2
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    • pp.59-65
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    • 1996
  • We studied exposure techniques and exposure dose for simple abdomen A-P projection for 41 medical facilities that are located in Seoul area. 1. The range of tube voltage used was 60 to 84 kVp, the average tube voltage used was 74 kVp 2. Only 17% of added filter was used. 3. Tube current mostly used was 200 mA, some of them used 400 mA. 4. The grid ratio mostly was used 10 : 1, 54 % of the rare earth screen was used in most facilities. 5. The average skin entrance dose was 4.15 mSv and the dose range was 1.05 mSv to 11.0 mSv.

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Analysis of Patient Exposure dose with Glass Dosimeter (Glass Dosimeter를 이용한 환자피폭선량에 관한 분석)

  • Kim, Jae-In;Choi, Won-Keun;Chang, Sung-Won;Oh, Chang-Seop;Lee, Kwan-Sup;Ha, Dong-Yoon
    • Korean Journal of Digital Imaging in Medicine
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    • v.11 no.1
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    • pp.15-20
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    • 2009
  • Far reducing medical radiation exposure and managing patient doses, Entrance surface doses(ESDs) were measured at Diagnostic Radiology Department in ASAN medical center, also we determined and compared with the Diagnostic Reference Level(DRL) of some other countries. ESDs were measured far the most common types of X-ray procedures, such as chest PA, lumbar spine AP, lumbar spine lateral, Pelvis AP, Skull PA. ESDs were measured by Glass dosimeter and Unfors Xi meter. Those were applied collimation center of phantom's entrance skin surface. The results of ESDs were compared Glass dosimeter with Unfors Xi meter. Those were measured within 5% statistical difference. It seemed well agreement at two devices. In most cases ESDs measured far the different types of X ray procedures were found to be lower than the DRL of IAEA, but ESDs on chest PA, lumbar spine AP, lumbar spine lateral, Pelvis AP, Skull PA were proximity ar excesses at DRL of advanced country. Through this study, we need an investigation and improvement at present diagnostic radiology exam system. Also, radiologists make an effort to reduce patient dose and having a technical skill.

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A Study on the Additional Absorbed Dose of Normal Tissues by Image Guided Radiation Therapy(IGRT) (영상유도 방사선 치료(IGRT)에 따른 정상 조직의 추가 피폭에 대한 연구)

  • Kim, Gha-Jung;Ryu, Jun-Min;Choi, Jun-Gu;Hong, Dong-Hee
    • The Journal of the Korea Contents Association
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    • v.16 no.1
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    • pp.75-81
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    • 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.