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Bayesian approaches for radiation dose-response estimation
Yeongwoo Park,Young Min Kim,Yongku Kim 한국데이터정보과학회 2020 한국데이터정보과학회지 Vol.31 No.4
Many people are exposed to radiation from frequently receiving X-rays or CT scans at the hospital. Exposure at low dose does not give an immediate response to the body. However, it is well known that the risk of cancer incidence rate is increasing over time. Therefore, in order to accurately quantify the risk of radiation exposure, many studies have been actively conducted. However, the Bayesian approach has not been rarely applied as a way to quantify radiation exposure risk. In this paper, the Bayesian approaches were introduced for several dose-response models to estimate the risk of radiation exposure, and the proposed model was applied to Life Span Study (LSS) solid cancer incidence data obtained from atomic bomb survivors (1958-2009). It was confirmed that the dose-response model of Linear nonthreshold (LNT), Quadratic, Linear-Quadratic, and Threshold showed similar results to those without the Bayesian analysis method. In the case of the piecewise linear dose-response model, the changes in slope associated with radiation exposure were found to vary with the dose ranges.
Estimation of the excess relative risk using the piecewise linear model with Gaussian process
Yeongwoo Park,Yongku Kim 한국데이터정보과학회 2020 한국데이터정보과학회지 Vol.31 No.6
As technology develops, many people are exposed to radiation in hospitals and living spaces. It is widely known that radiation-related cancer risk increases as the background rate increase over time. Accurately quantifying the risk of exposure to radiation is a major study in radiation epidemiology. The solid cancer incidence data among Life Span Study (1958-2009) was used to estimate the risk associated with radiation by using Bayesian analysis. First, we considered the piecewise linear model, which estimates the slope by dividing the dose range, as dose-response function. In the piecewise linear model, the slope tends to change rapidly at the cut points. In this paper, we consider the Gaussian process with a covariance matrix to allow a dose difference structure to the dose category slopes. Finally we compare the results with other models using Bayesian analysis. As a result, estimated risk appeared slightly smaller than the Piecewise linear model with general assumption.
Jae-Hyung Roh,Hyun Jun Cho,Jae-Hwan Lee,Yongku Kim,Yeongwoo Park,Jae-Hyeong Park,Hee-Soon Park,Minsu Kim,Hyang Gon Jin,Yeji Cheon,In-Whan Seong 대한심장학회 2020 Korean Circulation Journal Vol.50 No.4
Background and Objectives: There is insufficient evidence regarding the optimal treatment for asymptomatic carotid stenosis. Methods: Bayesian cross-design and network meta-analyses were performed to compare the safety and efficacy among carotid artery stenting (CAS), carotid endarterectomy (CEA), and medical treatment (MT). We identified 18 studies (4 randomized controlled trials [RCTs] and 14 nonrandomized, comparative studies [NRCSs]) comparing CAS with CEA, and 4 RCTs comparing CEA with MT from MEDLINE, Cochrane Library, and Embase databases. Results: The risk for periprocedural stroke tended to increase in CAS, compared to CEA (odds ratio [OR], 1.86; 95% credible interval [CrI], 0.62–4.54). However, estimates for periprocedural myocardial infarction (MI) were quite heterogeneous in RCTs and NRCSs. Despite a trend of decreased risk with CAS in RCTs (OR, 0.70; 95% CrI, 0.27–1.24), the risk was similar in NRCSs (OR, 1.02; 95% CrI, 0.87–1.18). In indirect comparisons of MT and CAS, MT showed a tendency to have a higher risk for the composite of periprocedural death, stroke, MI, or nonperiprocedural ipsilateral stroke (OR, 1.30; 95% CrI, 0.74–2.73). Analyses of study characteristics showed that CEA-versus-MT studies took place about 10-year earlier than CEA-versus-CAS studies. Conclusions: A similar risk for periprocedural MI between CEA and CAS in NRCSs suggested that concerns about periprocedural MI accompanied by CEA might not matter in real-world practice when preoperative evaluation and management are working. Maybe the benefits of CAS over MT have been overestimated considering advances in medical therapy within10-year gap between CEA-versus-MT and CEA-versus-CAS studies.