From the Department of Nuclear Medicine, China-Japan Friendship Hospital, Beijing, China.

Received for publication November 30, 2020; revision accepted December 2, 2020.

Conflicts of interest and sources of funding: none declared.

Correspondence to: Yumin Zheng, MD, PhD, Department of Nuclear Medicine, China-Japan Friendship Hospital, No. 2 Yinghua East Street, Chaoyang District, Beijing 100029, China. E-mail: [email protected].