*2.5.4 Non-invasive imaging for immunotherapy*

Most of the patients do not respond to immunotherapy especially the immune check point inhibitors (ICI). The traditional imaging methods only provide anatomic information and do not define the concrete representation of response or progression, especially pseudo-progression due to tumour infiltrating lymphocytes (TILs); and third, toxicities are a potential concern for the widespread use of immunotherapy, which is associated with an increased risk of cancer progression. As a result, a reliable and repeatable imaging approach is critical for identifying the patient group most or least likely to react to immunotherapy [77].

Molecular imaging, in combination with disease-specific imaging probes, can provide non-invasive, early, and dynamic information about the effects of immune cells or other cells in the tumour microenvironment (TME), as well as target

**Figure 3.** *Translation of PPM in to clinical practice.*

expression and biodistribution of immunomodulatory drugs in the body, allowing clinicians to predict which patients will benefit most from immunotherapy. Furthermore, integrating immunotherapy with molecular imaging may improve cancer immunotherapy precision. Immunotherapies are classified into four major categories: Immune cell-based therapies, ICIs, tumour vaccines, and CAR-T cell therapy are all examples of this [78].

**Figure 3** summarises the translation of PPM in to clinical practice.
