The Shepp & Vardi (1982) implementation of the EM algorithm for PET scan tumor estimation provides a point estimate of the tumor. The current study presents a closed-form formula of the observed Fisher information for Shepp & Vardi PET scan tumor estimation. Keywords: PET scan, EM algorithm, Fisher information matrix, standard errors.

翻译：Shepp & Vardi（1982）将EM算法应用于PET扫描肿瘤估计的实现，提供了肿瘤的点估计。本研究给出了Shepp-Vardi PET扫描肿瘤估计中观测Fisher信息的闭式公式。关键词：PET扫描，EM算法，Fisher信息矩阵，标准误差。