Treatment solutions for numerous diseases that combine therapies and diagnosis are referred to as theragnosis. Theragnosis is a new concept in next-generation medicine that integrates diagnosis and treatment at the same time. Theragnostic nanoparticles (NPs) combine diagnostic and therapeutic activities into a single integrated system, allowing for simultaneous diagnosis, therapy, and therapeutic response monitoring. Noninvasive imaging methods must be included in theragnostic NPs' diagnostic function. Theragnostic encompasses a wide range of issues, including personalised medicine, pharmacogenomics, and molecular imaging, to produce efficient new targeted medicines with acceptable benefit/risk to patients and a deeper molecular understanding of how to optimise medication selection. For successful theragnosis applications, imaging agents and drugs must be given efficiently, resulting in suitable imaging signal or drug concentration in the specific disease area.