Multidrug resistance (MDR) mediated by overexpression of P-glycoprotein (Pgp) is one of the best characterized transporter-mediated barriers to successful chemotherapy in cancer patients and is also a rapidly emerging target in the progression of neurodegenerative disorders such as Alzheimer’s and Parkinson’s diseases. Therefore, strategies capable of delivering chemotherapeutic agents into drug-resistant tumors and targeted radiopharmaceuticals acting as ultrasensitive molecular imaging probes for detecting functional Pgp expression in vivo could be expected to play a vital role in systemic biology as personalized medicine gains momentum in the twenty-first century. While targeted therapy could be expected to deliver optimal doses of chemotherapeutic drugs into the desired targets, the interrogation of Pgp-mediated transport activity in vivo via noninvasive imaging techniques (SPECT and PET) would be beneficial in stratification of patient populations likely to benefit from a given therapeutic treatment, thereby assisting management of drug resistance in cancer and treatment of neurodegenerative diseases. Both strategies could play a vital role in advancement of personalized treatments in cancer and neurodegenerative diseases. Via this tutorial, authors make an attempt in outlining these strategies and discuss their strengths and weaknesses.