**5.3 Nuclear Medicine Imaging**

In past 100 years a similar kind of model for neuroendocrine tumors has been developed that has used radionuclide gallium-68. This PET radiotracer has been chelated to DOTA-octreotate and used for diagnosis of tumor with higher sensitivity compared to Indium-111 octreotide imaging.

The disease of patients can be determined by using the gallium-68 DOTA-TATE for targeting the somatostatin receptor volume and having image using hybrid scanner like PET-CT (Positron Emission Tomography-Computer Tomography). Lutetium Octreotate Therapy is a radiopharmaceuticals which emits beta radiation is available in 5 medical centers in north America and European medical centers [27].

Some of the milestones in the field of theranostics becoming personalized medicine are as follows:


Theranostics targeted therapy is difficult in case of cancer treatment due to heterogeneity of cancer cells. Ibritumomab a monoclonal antibody detects B-cells and produces the beta/alpha-emitting radiometal for destroying the lymphoma. SPECT imaging confirms distribution of antibody in the body. The indium-111 combined with radionuclide yttrium-90 transports beta particles for killing the B-cells [28] (**Figure 3**).

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*Theranostics: New Era in Nuclear Medicine and Radiopharmaceuticals*

Zevalin therapy is used for determining the indications for relapsed or refractory, low-grade or follicular, B-cell non-Hodgkin's lymphoma. Zevalin is FDA approved for the treatment of relapsed or refractory low-grade follicular. In the year 2008 Zevalin was approved as the first-line drug for follicular lymphoma in the European Union.

The diagnostic component contains radiotracer, a contrast agent molecule, and a particulate system with either inherent physical property like optical, magnetic property or an acquired physical property such as, contrast enhanced ultrasound property or combinations of both. Combination systems exhibits dual functions

The therapeutic component includes drug molecule that is associated with diagnostic component or carrier system. Examples of the former are radiotracerlabeled non-peptide like gallium-68-labeled bisphosphonates for osteoblastic bone metastases and peptide-based molecules such as gallium-68-labeled somatostatin analogs for somatostatin receptor which targets neuroendocrine tumors. Examples of therapeutic components associated with a carrier system are where integrated entities are attaches to macromolecular carrier covalently. In addition to this, drug molecules co-encapsulation is done with diagnostic components such as chelated radiotracers and gadolinium (III), quantum dots, gold nanoparticle into particulate carrier systems namely polymeric nanospheres, liposomes, polymersomes, and

Cancer is a serious condition of heterogeneous group of diseases where there is uncontrolled and rapid cell growth. This is because of changes at genetic and/or epigenetic level in patient's body. Current treatment for cancer is chemotherapy,

Chemotherapy is not that much useful as a very low level of concentration of drug reaches the tumor. Moreover there is chances development of resistance during treatment and associated side effects. For example, chemotherapeutic agents known as taxanes have emerged as one of the most powerful classes of compounds to combat cancer, exhibiting a wide range of activity. The tubulin/microtubule complex has been proven to be a clinically useful antitumor target. The examples of chemotherapeutics that act *via* perturbation of tubulin polymerization include paclitaxel (Taxol®), docetaxel (Taxotere®), vinblastine, and discodermolide. First, docetaxel is a semi-synthetic derivative of paclitaxel. Next, vinblastine, unlike the other three compounds that all stabilize microtubules, aggregates tubulin and leads to microtubule depolymerisation. Randomized clinical trials evaluating docetaxel and paclitaxel in a first-line treatment setting for metastatic breast, lung, ovarian, and digestive cancers, as well as in the adjuvant setting for breast cancer, have confirmed that taxanes are leading contributors to the armamentarium of cancer treatments. Paclitaxel is used as a first-line chemotherapy treatment for NSCLC, but

like oximetry and detection in cellular and molecular imaging [29].

*DOI: http://dx.doi.org/10.5772/intechopen.91868*

**5.4 Theranostics: Zevalin therapy**

*5.4.1 Characteristics*

*5.4.1.1 Diagnostic component*

*5.4.1.2 Therapeutic component*

mesoporous silica nanoparticles.

**5.5 The application of theranostics in cancer**

radiotherapy, immunotherapy and surgery.

patients' acquired resistance becomes a critical problem.

**Figure 3.** *Theranostics in cancer targeting and treatment.*
