Journal of radiological science and technology (대한방사선기술학회지:방사선기술과학)

Korean Society of Radiological Science (대한방사선과학회)
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A Comparative Study of CTDI and the Effective Dose and the SNR according to the Area in the Abdominal CT

복부CT에서 면적에 따른 CTDI와 유효선량 및 SNR의 비교 연구

  • Choi, Sung-Jun (Department of Radiologic Science, Shinhan University) ;
  • Kang, Jun-Guk (Department of Radiologic Science, Shinhan University) ;
  • Kim, Su-In (Department of Radiologic Science, Shinhan University) ;
  • Kim, Youn-Ho (Department of Radiologic Science, Shinhan University) ;
  • Lee, Do-Gyeong (Department of Radiologic Science, Shinhan University) ;
  • Jung, Jin-Gyung (Department of Radiologic Science, Shinhan University) ;
  • Cho, Ar-A (Department of Radiologic Science, Shinhan University) ;
  • Jang, Jae-Hyeok (Department of Radiologic Science, Shinhan University) ;
  • Kweon, Dae-Cheol (Department of Radiologic Science, Shinhan University)
  • 최성준 (신한대학교 방사선학과) ;
  • 강준국 (신한대학교 방사선학과) ;
  • 김수인 (신한대학교 방사선학과) ;
  • 김윤호 (신한대학교 방사선학과) ;
  • 이도경 (신한대학교 방사선학과) ;
  • 정진경 (신한대학교 방사선학과) ;
  • 조아라 (신한대학교 방사선학과) ;
  • 장재혁 (신한대학교 방사선학과) ;
  • 권대철 (신한대학교 방사선학과)
  • Received : 2015.07.08
  • Accepted : 2015.09.17
  • Published : 2015.09.30
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Abstract

To obtain the best SNR (signal to noise ratio) due to changes in CTDI (computed tomography dose index) made for the purpose of setting the optimum image obtained by reducing the dose in abdominal CT. Abdominal CT scans of 59 patients a $400-499cm^2$ (n = 12), $500-599cm^2$ (n = 21), $600-699cm^2$ (n = 17), $700-799cm^2$ (n = 9) were separated by four groups and the effective dose was used in the Excel to get the area of the patient using the ImageJ program. Patients of CTDI, DLP, SNR, the effective dose were analyzed. Abdominal CT area was increased to 13 mGy in CTDI is 7.3 mGy, DLP to 732 in $394.4mGy{\cdot}cm$, also effective dose was 5.9 mSv increase in 11mSv. SNR is 15 dB was maintained at 12.7. CTDI according to the average of the abdominal area of 8.9 mGy, the average of the DLP was $481.54mGy{\cdot}cm$, the effective dose is calculated to be 7.2 mSV. Effective dose was calculated by multiplying the load factor of DLP in the abdomen showed no statistically significant difference of (p < .05), there was a significant difference in SNR (p > . 05). To improve image quality of abdominal CT scan image in consideration of the CTDI according to the volume of the patient it should be able to reduce the radiation exposure of the patients.

복부CT에서 면적을 산출하여 CTDI (computed tomography dose index) 변화에 따른 유효선량 및 SNR (signal to noise ratio)을 비교함으로써 진단적 가치가 높은 영상을 얻는 동시에 환자가 받는 피폭 선량 감소를 목적으로 한다. 복부CT 검사 환자 60명을 $400-499cm^2$ (12명), $500-599cm^2$ (21명), $600-699cm^2$ (17명), $700-799cm^2$ (9명) 4그룹으로 나누었다. 복부CT 데이터를 ImageJ 프로그램을 이용하여 환자의 면적을 산출하였고, CTDI, DLP, SNR 및 유효선량을 계산하였다. 복부면적이 증가할수록 CTDI는 7.3 mGy에서 13 mGy로 증가였고, DLP는 $394.4mGy{\cdot}cm$에서 732로, 유효선량에서도 5.9 mSv가 11mSv로 증가하였다. SNR은 12.7에서 15 dB을 유지하였다. 복부면적에 따른 CTDI의 평균은 8.9 mGy, DLP의 평균은 $481.54mGy{\cdot}cm$, 유효선량은 7.2 mSV로 산출되었다. 복부하중계수에 DLP를 곱하여 산출한 유효선량은 통계적의로 유의한 차이가 없었고 (p < .05), SNR에서는 유의한 차이가 있었다(p > .05). 복부CT 영상검사에서 영상의 질 향상을 위해서는 환자의 면적에 따른 CTDI를 고려하여 환자의 피폭선량을 감소시킬 수 있어야 한다.

Keywords

References

  1. Jung MY, Kweon DC, Kwon SI: Effectiveness of bismuth shield to reduce eye lens radiation dose using the photoluminescence dosimetry in computed tomography, J Korean Soc Radiol Technol, 32(3), 307-312, 2009
  2. Yoo BG, Kweon DC, Lee JS, Jang KJ, Jeon SH, Kim YS: Comparison radiation dose of Z-axis automatic tube current modulation technique with fixed tube current multi-detector row CT scanning of lower extremity venography, J Radiat Prot, 32(3), 123-133, 2007
  3. Hricak H, Brenner DJ, Adelstein SJ, Frush DP, Hall EJ, Howell RW, et al. Managing radiation use in medical imaging: a multifaceted challenge, Radiology, 258, 889-905, 2011 https://doi.org/10.1148/radiol.10101157
  4. Mettler FA Jr, Bhargavan M, Faulkner K, Gilley DB, Gray JE, Ibbott GS, et al. Radiologic and nuclear medicine studies in the United States and worldwide: frequency, radiation dose, and comparison with other radiation sources-1950-2007. Radiology 2009;253:520-531 https://doi.org/10.1148/radiol.2532082010
  5. Brenner DJ, Elliston CD: Estimated radiation risks potentially associated with full-body CT screening, Radiology, 232(8),735-738, 2004 https://doi.org/10.1148/radiol.2323031095
  6. Brenner DJ: Radiation risks potentially associated with low-dose CT screening of adult smokers for lung cancer, Radiology, 231(2), 440-445, 2004 https://doi.org/10.1148/radiol.2312030880
  7. Yoshinaga S, Mabuchi K, Sigurdson AJ, Doody MM, Ron E: Cancer risks among radiologists and radiologic technologists review of epidemiologic studies, Radiology, 233(2), 313-321, 2004 https://doi.org/10.1148/radiol.2332031119
  8. Kweon DC, Lee JS, You BG: Radiation dose reducing effect during the AEC system in the chest and abdomen of the MDCT scanning, The Journal of the Korea Contents Association, 9(3), 225-231, 2009 https://doi.org/10.5392/JKCA.2009.9.3.225
  9. European Commission. European guidelines on quality criteria for computed tomography (EUR 16262 EN). Luxembourg, Luxembourg: European Commission, 2000
  10. Mulkens T H, Bellinck P, Baeyaert M, Ghysen D, Van Dijck X, Mussen E, Venstermans C, Termote JL: Use of an automatic exposure control mechanism for dose optimization in multi-detector row CT examinations: clinical evaluation, Radiology, 237(1), 213-233, 2005 https://doi.org/10.1148/radiol.2363041220
  11. Kalra MK, Maher MM, Toth TL, Strategies for CT radiation dose optimization, Radiology, 230, 619-628, 2004 https://doi.org/10.1148/radiol.2303021726
  12. Huda W, Scalzetti EM, Levin G: Technique factors and image quality as functions of patient weight at abdominal CT, Radiology, 217, 430-435, 2000 https://doi.org/10.1148/radiology.217.2.r00nv35430
  13. Kweon SO, Dong KR, Kweon DC, Goo EH, Choi J, Chung WK: Estimate of radiation does in MDCT using patient weight, Korean J Med Phys 21(3), 246-252, 2010
  14. Jung B, Mahnken AH, Stargardt A, Simon J, Flohr TG, Schaller S, Koos R, Gunther RW, Wildberger JE: Individual weight CT adapted examination protocol in retrospectively ECG-gated MSCT of the heart, Eur Radiol, 13(12), 2560-2566, 2003 https://doi.org/10.1007/s00330-003-2111-5
  15. Irle T, Inoue H: Individual modulation of the tube current-seconds to achieve similar levels of image noise in contrast-enhanced abdominal CT, Am J Roentgenol, 184(5), 1514-1518, 2005 https://doi.org/10.2214/ajr.184.5.01841514
  16. Bae KT, Seeck BA, Hildebolt CF, Tao CF, Zhu F, Kanematsu M, Woodard PK: Contrast enhancement in cardiovascular MDCT: effect of body weight, height, body surface area, body mass index, and obesity, Am J Roentgenol, 190(3), 777-784, 2008 https://doi.org/10.2214/AJR.07.2765
  17. Starck G, Lonn L, Cederblad A, Forssell-Aronsson E, Sjostrom L, Alpsten M: A method to obtain the same level of CT image noise for patients of various sizes, to minimize radiation dose, Br J Radiol, 75(890), 140-150, 2002 https://doi.org/10.1259/bjr.75.890.750140
  18. Boone JM, Geraghty EM, Seibert JA, Wootton-Gorges SL: Dose reduction in pediatric CT: a rational approach, Radiology, 228(2), 352-360, 2003 https://doi.org/10.1148/radiol.2282020471
  19. Christner JA1, Zavaletta VA, Eusemann CD, Walz-Flannigan AI, McCollough CH: Dose reduction in helical CT: dynamically adjustable z-axis X-ray beam collimation. Am J Roentgenol, 194(1), W49-55, 2010 https://doi.org/10.2214/AJR.09.2878