Figure 5.

Concept of “Dual Drug – Dual Microsphere” TACE: delivery of DEE microspheres containing different radiopacifiers and different drugs to specific regions within a tumor, imaged with photon counting CT. Microspheres containing different radiopacifiers and loaded with different drugs are delivered sequentially to different parts of the tumor for rational targeting of discrete intratumoral regions based on drug mechanism of action and expected tumor microenvironment. For example, microspheres with a hypoxia activated drug (blue) may be delivered to hypoxic tumor regions while microspheres with an immune-modulating agent may be directed to immunologically active regions at the tumor margin (yellow). The microspheres cannot be distinguished based on standard unfiltered CBCT (left). Subsequent photon counting CT shows spatial distribution of the two DEE microspheres with different radiopacifiers (center) allowing inferences as to the distribution of the two associated drugs, as shown on the inlay.