A delivery system for deploying an implantable sensor assembly at an implantation site in a patient, the sensor assembly including a sensor element and an anchor. The dye remains encapsulated during cleansing andor treating, such as during hand washing for the recommended 15-20 seconds. In one particular embodiment, for example, a grouping of bits, such as a 32-bit word, for example, is stored in inverted form if more than half of the bits have a bit value of logic 1 rather than logic 0. The sensor may be a passive infrared sensor mounted directly to the fixture.