Nuclear Medicine

Theranostics combines molecular imaging with targeted radionuclide therapy by using related radiopharmaceuticals to identify a biological target and then deliver radiation to cells expressing that target. This approach includes peptide receptor radionuclide therapy for selected somatostatin receptor-positive tumours, PSMA-targeted radioligand therapy for eligible patients with advanced prostate cancer, and MIBG therapy for selected MIBG-avid tumours. PET-CT, SPECT-CT, post-treatment imaging, and dosimetry may be used to confirm target expression, assess eligibility, plan treatment, evaluate radiopharmaceutical distribution, and monitor response.

Radioiodine therapy uses iodine-131, which is taken up by functioning thyroid tissue. It may be used after surgery for selected differentiated thyroid cancers to treat remaining thyroid tissue or iodine-avid disease, and it may also be used for certain non-cancerous thyroid conditions. Suitability depends on the diagnosis, pathology, risk assessment, iodine uptake, previous treatment, and clinical factors. Preparation may include thyroid-stimulating hormone elevation, a low-iodine diet, and adjustment of certain medicines, followed by temporary radiation-safety precautions after treatment.

Bone-targeted radionuclide therapy uses radiopharmaceuticals that localise in areas of increased bone activity. Depending on the agent and clinical indication, it may be used to relieve pain from selected bone metastases or as part of disease-directed treatment. Eligibility is based on the underlying cancer, pattern of bone involvement, symptoms, blood-cell counts, kidney function, previous treatments, and the presence of disease outside the bones.

Radioembolisation is a targeted internal radiation treatment used for selected primary or metastatic tumours in the liver. An interventional radiologist guides a catheter into the arteries supplying the tumour, through which microscopic beads containing a radioactive isotope (Yttrium-90) are delivered. Treatment planning generally includes angiographic mapping, nuclear medicine imaging, assessment of blood flow outside the liver, and calculation of the required activity. The procedure is planned jointly by interventional radiology, nuclear medicine, medical physics, and the wider oncology team.

Radiosynovectomy is a nuclear medicine treatment for selected chronic inflammatory joint conditions rather than cancer. A small amount of a radiopharmaceutical is injected directly into the affected joint to reduce inflammation in the synovial lining. It may be considered when persistent joint swelling or bleeding has not responded adequately to other treatments. Suitability depends on the underlying condition, joint assessment, previous treatment, and the absence of contraindications such as joint infection or pregnancy.