PET tracks cancer treatment

Researchers are using positron emission tomography (PET) scanning to track the progress of virus therapies as they attack cancer cells inside a living body, without using invasive techniques.

Scientists from Imperial College London and Queen Mary’s School of Medicine and Dentistry developed the technique. The research demonstrates how PET scanning can be used to see both how the virus behaves and how the cancer responds. This means that scientists can gain an accurate picture of the effects of the drug therapies whilst they are working in the body, and refine and improve them accordingly.

Ovarian cancer causes changes that are difficult to quantify by conventional imaging due to the location, presentation and biological characteristics of the disease. PET scanning, however, is a nuclear medicine imaging technique which produces a three dimensional image of the body. It enables researchers to see early changes in the development of the disease which happen before changes in the size of the tumour.

Self-replicating viral therapies, previously mainly trialled on animal models, are versions of viruses that are tailored to replicate inside the body and to infect and kill cancer cells. They are designed to multiply and kill cancerous cells rather than healthy ones.

Trials in animal models have shown that these therapies can be effective in fighting tumours but that their effectiveness is limited to a certain time period, after which point the viruses die. The researchers hope that analysing the behaviour of the viruses using PET scanning will allow them to alter the viruses' properties to increase their effectiveness.

PET scanning works by scanning for a radioactive tracer injected into the body. Where the viral therapies kill cancerous cells, their uptake of the tracer is reduced and these changes are visible on the scanner.