Earticle

초록

영어

Background: This study aims to determine the effective atomic number (Zeff) from dual-energy image sets obtained using a conventional computed tomography (CT) simulator. The estimated Zeff can be used for deriving the stopping power and material decomposition of CT images, thereby improving dose calculations in radiation therapy. Materials and Methods: An electron-density phantom was scanned using Philips Brilliance CT Big Bore at 80 and 140 kVp. The estimated Zeff values were compared with those obtained using the calibration phantom by applying the Rutherford, Schneider, and Joshi methods. The fitting parameters were optimized using the nonlinear least squares regression algorithm. The fitting curve and mass attenuation data were obtained from the National Institute of Standards and Technology. The fitting parameters obtained from stopping power and material decomposition of CT images, were validated by estimating the residual errors between the reference and calculated Zeff values. Next, the calculation accuracy of Zeff was evaluated by comparing the calculated values with the reference Zeff values of insert plugs. The exposure levels of patients under additional CT scanning at 80, 120, and 140 kVp were evaluated by measuring the weighted CT dose index (CTDIw). Results and Discussion: The residual errors of the fitting parameters were lower than 2%. The best and worst Zeff values were obtained using the Schneider and Joshi methods, respectively. The maximum differences between the reference and calculated values were 11.3% (for lung during inhalation), 4.7% (for adipose tissue), and 9.8% (for lung during inhalation) when applying the Rutherford, Schneider, and Joshi methods, respectively. Under dual-energy scanning (80 and 140 kVp), the patient exposure level was approximately twice that in general single- energy scanning (120 kVp). Conclusion: Zeff was calculated from two image sets scanned by conventional single-energy CT simulator. The results obtained using three different methods were compared. The Zeff calculation based on single-energy exhibited appropriate feasibility.

목차

ABSTRACT
Introduction
Material and Methods
1. CT, Reference Phantom, and Image Processing
2. Reference Calculation of the Electron Density (ED,re) and Zeff
3. Estimation of Zeff from the DE Image Set
4. CTDI Measurement
Results and Discussion
Conclusion
References

키워드

저자

• Seongmoon Jung [ Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea ]
• Bitbyeol Kim [ Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea ]
• Jung-in Kim [ Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea ]
• Jong Min Park [ Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea; Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea; Robotics Research Laboratory for Extreme Environments, Advanced Institute of Convergence Technology, Suwon, Korea ]
• Chang Heon Choi [ Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea ] Corresponding Author

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  방사선방어학회지 [Journal of Radiation Protection and Research]

• 간기

  계간

• pISSN

  2508-1888

• 수록기간

  1976~2026

• 등재여부

  KCI 등재,SCOPUS

• 십진분류

  KDC 559 DDC 629