Putting ‘clear’ into nuclear medicine: a decade of PET/CT development

Excerpt

Combining data from different imaging modalities is far from being a new idea. Hand-drawn contours on early thyroid scans constituted a rough anatomical reference for images of thyroid function acquired using trace amounts of radioactive iodine. When analogue imaging with planar X-rays and Polaroid photos of radiotracer distributions gave way to the digital imaging era of the CT scanner and emission tomography, visual correlation of structure and function became possible. The next step, beginning in the late 1980s, was the development of computer software to co-register the images from different modalities, a development that was applied primarily to brain imaging. However, even though non-invasive anatomical and functional imaging became well-established diagnostic procedures within radiology and nuclear medicine, little attention was actually paid to the co-registration of images from the different modalities. What were the reasons for this? One reason was that accurate registration of anatomy and function was never really considered essential for the interpretation of the images and access to multimodality data was rarely routine and certainly not straightforward. Furthermore, anatomical and functional images were typically acquired in different departments and read by different specialists, a situation that did little to promote the use of software fusion techniques. Thus, up until the mid 1990s, and despite the expenditure of considerable intellectual effort, image fusion techniques had little impact on public healthcare. The arrival of PET/CT has changed this situation forever. …