E2559. Breaking Biodistribution: A Systematic Approach to Interpreting Nuclear Medicine Studies With Abnormal Radiopharmaceutical Distribution
Authors
Kathryn Welch;
University of New Mexico
Sally Midani;
University of New Mexico
Hannah Hodges;
University of New Mexico
Shana Elman;
University of New Mexico
Thomas Anderson;
University of New Mexico
Background
Interpreting nuclear medicine studies can be challenging when the biodistribution of the radiopharmaceutical is abnormal. There are many potential causes of abnormal biodistribution; identifying the correct cause is critical to accurate interpretation of the study.
We present a systematic approach to guide users in identifying the cause of the abnormal biodistribution. Causes can be divided into 3 main categories: patient-specific factors, problems with radiopharmaceutical preparation or administration, and problems with instrumentation. We provide an algorithm for differentiating among these possibilities and present cases demonstrating common causes of abnormal biodistribution in each of these categories.
Educational Goals / Teaching Points
This presentation will familiarize learners with common causes of abnormal biodistribution in nuclear medicine studies, identify strategies to differentiate between pathologic radiopharmaceutical uptake and abnormal biodistribution caused by other factors, and provide an algorithm for differentiating between potential causes of abnormal biodistribution (patient specific factors, problems with radiopharmaceutical preparation or administration, and problems with instrumentation).
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Radiopharmaceutical biodistribution is defined as the normal distribution of radiopharmaceutical in the body when no pathology is present. A disease process can result in pathologic uptake of the radiopharmaceutical; i.e., abnormal uptake that occurs as the direct result of a disease process. Radiopharmaceutical uptake can also deviate from normal biodistribution due to nonpathologic causes. When this occurs, the term “abnormal biodistribution” applies, and identifying the cause is crucial to accurate interpretation. Causes of abnormal biodistribution falls into 3 categories (patient specific factors, problems with radiopharmaceutical preparation or administration, and problems with instrumentation). We present examples of abnormal biodistribution from a variety of nuclear medicine studies that fall into these 3 categories. In addition, we provide an algorithm for ascertaining the category of abnormal biodistribution.
Conclusion
When abnormal biodistribution is seen in nuclear medicine studies, determining the cause and differentiating from true pathologic uptake are essential for accurate interpretation. However, this can be a challenging task. We have provided a systematic approach to identifying and characterizing abnormal biodistribution, which will empower radiologists when interpreting nuclear medicine studies in their day-to-day practice.
