The FDA has created a formal regulatory category for a type of tumor marker that is injected as a liquid and changes into a solid inside the body, giving radiation oncologists a reference point for aiming treatment beams and giving future manufacturers a faster route to market.
The final order classifying the device type places the phase-changing fiducial marker for radiation therapy in class II with special controls, codified at 21 CFR 892.5727. The agency defines the device as a single-use, sterile liquid material that changes phase in situ when injected into tissue to aid radiation therapy, intended to be visualized using one or more imaging methods.
