1. Department of Biomedical Engineering & Environmental Sciences, National Tsing-Hua University , Hsinchu 30013, Taiwan, R.O.C
2. Health Physics Division, Institute of Nuclear Energy Research , Taoyuan 32546, Taiwan, R.O.C
3. Nuclear Science and Technology Development Center, National Tsing Hua University , Hsinchu 30013, Taiwan, R.O.C
4. Department of Diagnostic Radiology and Intervention, Chang Gung Memorial Hospital at Linkou , Taoyuan 333423, Taiwan, R.O.C