Size-Specific Dose Estimation In the Korean Lung Cancer Screening Project: Does a 32-cm Diameter Phantom Represent a Standard-Sized Patient in Korean Population?.
10.3348/kjr.2018.19.6.1179
- Author:
Eun Young KIM
1
;
Tae Jung KIM
;
Jin Mo GOO
;
Hyae Young KIM
;
Ji Won LEE
;
Soojung LEE
;
Jun Tae LIM
;
Yeol KIM
Author Information
1. Department of Radiology, Gachon University Gil Medical Center, Incheon 21565, Korea.
- Publication Type:Original Article
- Keywords:
Low-dose CT;
Radiation dose;
Radiation dosage;
Early detection
- MeSH:
Body Mass Index;
Body Size;
Cone-Beam Computed Tomography;
Humans;
Korea;
Lung Neoplasms*;
Lung*;
Mass Screening*;
Overweight;
Pilot Projects;
Radiation Dosage;
Radiation Exposure;
Thinness;
Tomography, X-Ray Computed
- From:Korean Journal of Radiology
2018;19(6):1179-1186
- CountryRepublic of Korea
- Language:English
-
Abstract:
OBJECTIVE: The purposes of this study were to evaluate size-specific dose estimate (SSDE) of low-dose CT (LDCT) in the Korean Lung Cancer Screening (K-LUCAS) project and to determine whether CT protocols from Western countries are appropriate for lung cancer screening in Korea. MATERIALS AND METHODS: For participants (n = 256, four institutions) of K-LUCAS pilot study, volume CT dose index (CTDI(vol)) using a 32-cm diameter reference phantom was compared with SSDE, which was recalculated from CTDI(vol) using size-dependent conversion factor (f-size) based on the body size, as described in the American Association of Physicists in Medicine Report 204. This comparison was subsequently assessed by body mass index (BMI) levels (underweight/normal vs. overweight/obese), and automatic exposure control (AEC) adaptation (yes/no). RESULTS: Size-specific dose estimate was higher than CTDI(vol) (2.22 ± 0.75 mGy vs. 1.67 ± 0.60 mGy, p < 0.001), since the f-size was larger than 1.0 for all participants. The ratio of SSDE to CTDI(vol) was higher in lower BMI groups; 1.26, 1.37, 1.43, and 1.53 in the obese (n = 103), overweight (n = 70), normal (n = 75), and underweight (n = 4), respectively. The ratio of SSDE to CTDI(vol) was greater in standard-sized participants than in large-sized participants independent of AEC adaptation; with AEC, SSDE/CTDI(vol) in large- vs. standard-sized participants: 1.30 ± 0.08 vs. 1.44 ± 0.08 (p < 0.001) and without AEC, 1.32 ± 0.08 vs. 1.42 ± 0.06 (p < 0.001). CONCLUSION: Volume CT dose index based on a reference phantom underestimates radiation exposure of LDCT in standard-sized Korean participants. The optimal radiation dose limit needs to be verified for standard-sized Korean participants.
