A Paris System-Based Implant Approach to Hyperthermia Cancer Tumor with Gold Seeds and Ultrasound

A Paris system-based implant approach has been used to improve the bio-heat distribution from implanted gold rods in insonated tissues. Experiments with single-plane implants using parallel equidistant 1.018 ± 0.015 cm height and 0.136 ± 0.001 cm diameter 24-K gold rods) arranged in triangular and square shapes were performed in Mus musculus white mice (medial dorsal region). The mice were anesthetized and gold rods were implanted by means of a trocar needle and the implanted region was insonated with a 4-cm diameter transducer oscillating with a nominal frequency of 1 MHz and power of about 75 W. Intramuscular tissue temperature measurements were recorded using implantable needle type thermocouples affixed to a portable Fluke thermometer. Superficial tissue temperature profile was also measured with a FLIR infrared camera and thermographic analysis was performed using the ImageJ computer software. In both cases, the central implant planes have been assigned to that approximately bisects all the implanted rods. Measured with the needle type thermistor, for the triangular implant, the percentage deviation between the maximum and minimum temperature within the triangular plane was 5%. For a square shape, this percentage deviation was 6%. The thermographic analysis have shown a deviation of 3 and 5% for the triangular and square shapes, respectively. The Paris system-based implant approach for gold rods implanted in tissue and exposed to ultrasound may greatly improve the bio-heat propagation and sustain a constant temperature profile inside triangular and square patterns formed by gold rods implants. Additionally, the Paris system may minimize ablations areas and treatment length in hyperthermia if used in cancer tumor treatment with gold seeds and ultrasound.