Combined Modalities

Fig. 1: PET image

Fig. 1: PET image

Molecular imaging offers physicians a unique insight into the workings of the human body at a cellular and molecular level, enabling them to diagnose and to characterize potential disease at a very early stage. To correlate the biological processes with anatomical location in the body, molecular imaging devices are integrated with CT and MRI scanners (Figure 1) 1. Computers are used to fuse the biological and anatomical images together to help doctors make better diagnostic and therapeutic decisions.

PET & CT exposes the patient to a small amount of ionizing radiation. The exact amount varies according to the type and length of the procedure and this in turn is associated with a low risk to the patient. Doctors and manufacturers know about these risks and do all they can to minimize radiation dose, keeping the exposure time to a minimum. These risks, however, are remote and experts consider them to be far outweighed by the benefits of an accurate diagnosis and treatment. Nevertheless, women should always inform their physician or X-ray technologist if there is any possibility that they are pregnant.

medicalradiatoin_Storyboard EN_PET_MR

                                  Fig. 2: PET-MR image

In 2010, a new hybrid imaging modality was introduced: known as MR-PET or PET/MR. It combines the technologies of both MR and PET. Across the globe, there are around 100 hybrid MR-PET systems installed, most of them in university hospitals, research institutes and larger imaging centers. In order to generate a whole-body PET image, a small amount of a radioactive substance is injected into the patient’s bloodstream prior to the scan. At the same time, a high-resolution magnetic resonance imaging (MRI) exam is performed which does not utilize any additional ionizing radiation.

Where both PET and MRI imaging are required to resolve diagnostic questions, the MR-PET has a key benefit: Two examinations are performed in a single scan. This saves time: The patient needs just one examination, and the physician receives both results at the same time. Furthermore, MRI can provide additional soft tissue in contrast to CT.

1. HK Sanatorium & Hospital, Hong Kong