Abstract :
"We need to add more dimensions to our effort!" This is probably a typical comment in any business or research meeting. This was exactly what we did in 2003: we expanded our research efforts from two dimensional (2-D) X-ray breast imaging into three dimensional (3-D) imaging. Actually, we are now looking to expand from 3-D X-ray breast imaging into 4-D imaging. Similar efforts are ongoing with many other imaging modalities. The question to be addressed in this article is whether it is indeed worthwhile pursuing to add more dimensions to a medical imaging modality. For us physicists or engineers, the answer tends to be "Of course, the more dimensions the better because it would provide more information about the patient." In reality, adding more dimensions is often achieved with a stiff price. Sometimes this means higher cost of the imaging modality or increased radiation risk to the patient, which we may be willing to incur if the benefit is worth it. However, the price could also be an excessively long scanning time or excessively high patient dose, either of which may make the new imaging technique impractical to implement and use. In this article, we will discuss the benefits of moving to higher dimensionality and the pitfalls of doing so. We will also discuss how we may judge whether to add more dimensions to a medical imaging modality and how we can achieve the same improvement without doing so.
