Uses in Oncology
With conventional imaging analysis a two dimensional measurement is used to characterize a three dimensional object. In Figure 1 the 2D red line represents the standard RECIST measurement of a large tumor in a baseline scan. Figure 2 represents a follow up scan of the same tumor which has cavitated and lost approximately 70% of its bulk. However, the standard RECIST measure is roughly unchanged.
Today's newer therapies work from inside the tumor so overall length may not change. To properly assess these therapies you need to incorporate quantitative analysis which is able to take advantage of the 3D information available from imaging modalities such as CT and MR. With this information we can conduct sensitive measurements of tumor volume, blood flow and vascular permeability; measurements that will provide us with much greater insight to a compound's mechanism of action, and more importantly, a patient's response to treatment.