Introduction of Y90-PET-CT Post Radioembolisation Therapy Scans

Yttrium-90, attached to microspheres, usually referred to as 90Y-microspheres or Y-90 radioembolisation, can be used in some cases to treat patients with liver tumours or liver metastasis. The treatment aim is to infuse the 90Ymicrospheres into the patient's liver. The microspheres get trapped in the lesions of micro-blood vessels while the yttrium-90, a radioactive compound, delivers radiation doses locally at these sites and damages the diseased cells.

Therapy is performed in such a way the 90Y-microspheres are localised in the tumour areas minimising damage to the healthy liver tissue. This treatment requires many steps involving professionals from different medical disciplines.

Patients are scanned in the nuclear Medicine Department on a gamma camera the day after the treatment. This scan is referred as Y-90 bremsstrahlung-SPECT. This posttherapy scan provides a 3-dimensional (3D) image of the distribution of the therapeutic agent in the patient's abdomen so an assessment of how much of the therapeutic agent has gone to the sites of disease can be performed.

In this research project, the investigators would like to evaluate an alternative post-therapy scan to the one routinely performed on the gamma camera. The alternative scan is done on a PET-CT scanner and is referred to as Y90-PET-CT. This type of scan has been reported to provide improved quality images, providing more accurate information on the distribution of the patients therapeutic dose.

For this research project, the investigators will invite a small number of patients undergoing this therapy to be scanned twice after treatment: with the current post-therapy scan on a gamma camera; and with the newly proposed scan method, Y90-PET-CT. Depending on the outcomes of this project, assessed by an expert panel of radiologists and medical physicists, the investigators will determine whether we will introduce this new scanning method into clinical practice in the future.