X-ray imaged implanted thermometers

Implanted thermometers and reader product, comprising:

• 1) an imager which images x-radiation;
• 2) a source which provides an x-radiation beam overlapping the imager;
• and
• 3) a plurality of thermometers implanted in a body from where they can not be imaged by visible light, any first thermometer from the plurality of thermometers comprising:
• 3.1) a first channel and a first bulb terminating the first channel, the first channel and the first bulb enclosing a first fluid, the first fluid moving along the first channel to a first fluid length functionally related to a first bulb temperature, a first fluid image length of the first fluid length being projected outside the body by the beam and imaged by the imager;
• and
• 3.2) fixed first markers with a first markers image being projected outside the body by the beam and imaged by the imager, the first markers providing a first calibration length, a first calibration image length of the first calibration length being projected outside the body by the beam and imaged by the imager, with a first ratio of the first fluid image length to the first calibration image length being functionally related to the first bulb temperature, where any second thermometer from the plurality of thermometers having fixed second markers with a second markers image projected outside the body by the beam and imaged by the imager being distinct from the first markers image independently of relative positions and orientations of the first thermometer and the second thermometer.