In interpreting scintillation images, one often is confronted with a variety of deviations from the typically normal study that need not represent definite pathology. Apart from normal anatomic variants in the position, shape, or configuration of an organ, one must also be prepared to appreciate alterations due to the radiodiagnostic agent employed and aberrations caused by faulty or improperly used instruments. Additionally, physiologic and/or functional changes associated with specific organ studies have provided a major source of error in routine image interpretation. It is the purpose of this article to acquaint (or reacquaint, as the case may be) the reader with many of these problems so that they may easily recognize them and, one hopes, improve their overall interpretative abilities. The discussion will follow the lines of general considerations relating to instrumentation and radiopharmaceuticals followed by specific organ considerations. In this type of review, some intentional as well as some unintentional omissions may appear. The author hopes that most of the common sources of error have been included. Undoubtedly, some readers may think of other problems that they may personally have been confronted with
