Radiotheranostics, an emerging and transformative approach in nuclear medicine, represents the convergence of diagnostic imaging and targeted radiotherapy. This integrated methodology is revolutionising managing and treating various diseases, particularly cancer, by facilitating personalised and precision medicine.

At the heart of radiotheranostics lies the use of radiopharmaceuticals – compounds that are labelled with radioactive isotopes. The uniqueness of radiotheranostics stems from its ability to use these compounds both for the diagnostic imaging of diseases and for their subsequent treatment. This dual functionality is a significant advancement over traditional methods, where diagnosis and treatment are often distinct and separate processes.

In the diagnostic phase, radiotheranostics involves the administration of a radiolabelled compound, which has an affinity for specific cells or receptors that are characteristic of the disease being targeted. Commonly, these are cancer cells expressing particular proteins or antigens. Once administered, these compounds accumulate in the target tissues and emit radiation that can be detected and visualised using imaging techniques such as Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT). This allows for precise localisation and characterisation of the disease, aiding in accurate diagnosis and staging.

Following diagnosis, the therapeutic phase involves administering a similar or sometimes the same compound, labelled with a different radioactive isotope that emits therapeutic radiation, such as beta or alpha particles. This radiation targets diseased cells directly, minimising damage to surrounding healthy tissues. The targeted nature of this therapy allows for high doses of radiation to be delivered directly to the tumour or diseased cells, offering a potentially more effective and less toxic treatment compared to conventional methods like chemotherapy or external beam radiation.

One of the most well-known applications of radiotheranostics is in the treatment of neuroendocrine tumours (NETs) using the somatostatin receptor pathway. Diagnostically, compounds like Gallium-68 Dotatate are used to image NETs, and therapeutically, Lutetium-177 Dotatate is employed to deliver targeted radiation to the tumour cells.

Another notable application is in the management of prostate cancer using agents targeting the Prostate-Specific Membrane Antigen (PSMA). Gallium-68 or Fluorine-18 labelled PSMA compounds are used for diagnostic imaging, while Lutetium-177 or Actinium-225 labelled PSMA compounds are utilised for targeted therapy.

The advantages of radiotheranostics are manifold. It enables precise disease targeting, reduces systemic side effects, and can be used in cases where other treatment modalities are ineffective. It also allows for real-time monitoring of treatment response, enabling adjustments to be made as necessary.

However, there are challenges in the widespread adoption of radiotheranostics. These include the need for specialised facilities and personnel trained in handling radiopharmaceuticals, regulatory hurdles, and the high cost of development and treatment. Nonetheless, the potential of radiotheranostics in improving patient outcomes is significant, and ongoing research and development in this field are likely to expand its applications and accessibility in the future.

Open Medscience