The positron-emitting radiohalogens 18 F, 75 Br, 76 Br, and 124 I are reviewed regarding their relevance for positron emission tomography (PET) in oncology. Relevant production routes of these cyclotron-generated isotopes are given, followed by publications that deal with applications of these radiohalogens. This article tries to cover the whole literature for the non-conventional isotopes 75 Br, 76 Br, and 124 I. From the literature on 18 F, only articles since 2000 are considered. Here, the emphasis is also given to alternative biomarkers beyond [ 18 ]2-fluoro-2-deoxyglucose ([ 18 F]FDG). Contents 1. Introduction 2. Fluorine-18 3. Bromine-75 4. Bromine-76 5. Iodine-124 6. Conclusions