Theranostics is a type of precision medicine in which targeted radiolabeled compounds are being used for both diagnosis and treatment. Targeted therapies can increase therapeutic effectiveness while limiting side effects. Since the publication of the NETTER1 trial results (1,2), the use of 177Lu-DOTATATE to treat neuroendocrine tumor (NET) patients has increased significantly. The protocol for the trail was four 200 mCi administered treatments at 8-week intervals. This protocol received FDA approval in the United States and has become the standard of care (SOC) for most sites throughout the world. On the other hand, there is a large group of physicians and scientists that believe 177Lu-DOTATATE treatments should be personalized for each patient. 177Lu emits electrons for therapy, but it also emits gammas that can be used for imaging. Therefore, it is possible to quantitate dose to a person’s organs at risk (OAR) and tumors using imaging techniques, such as SPECT/CT. Assessing OAR dosimetry after each treatment allows for personalization of 177Lu-DOTATATE therapy. Retrospective studies have demonstrated significant lengthening of progression free survival (33 vs. 15 mos) and overall survival (54 vs. 25 mos) when patients were able to continue treatments up to 23 Gy delivered dose to their kidneys (4). In addition to OAR dosimetry, there is growing interest in personalizing therapies based upon tumor biology. Thus, the goal of this work is to develop and validate a cost effective, patient friendly technology that will enable personalization of 177Lu-DOTATATE using daily measurements of the radioactivity in the patient’s OAR and tumors without requiring serial visits to an imaging center. The Personalized Remote Radiation Tracking Portable Organ Dosimetry Device, PRRT PODD or PODD for short, is a patient-friendly radiation measuring device that the patient can use in their homes. The primary OAR is the patient’s kidney; however, the PODD will also provide data for accurate dose estimation of other OAR and physician selected tumors, thus enabling treatment personalization based upon maximum tolerated dose to OAR, cumulative tumor dose, therapeutic ratio (i.e., ratio of tumor dose to dose to OAR), or other dosimetry-based metrics. Our project consists of four specific aims: 1) Design, develop, and characterize compact imaging detectors and associated software tools for use with the PODD; 2) Use realistic, digital NET patient phantoms and simulation tools to optimize PODD design for both OAR and tumor dosimetry; 3) In clinic patient studies to validate quantitative organ and tumor measurement capabilities of PODD; and 4) Conduct a patient study including at home measurements comparing OAR and tumor dosimetry estimates using PODD to serial SPECT/CT imaging. At the conclusion of this project, we will have validated our PRRT PODD technology on a 36-patient cohort and the technology will be ready to support clinical trials to study the benefits to patients...