Effective estimation and computer control of minimum tumour temperature during conductive interstitial hyperthermia

Area of Science:

• Oncology
• Biomedical Engineering
• Medical Physics

Background:

• Heat therapy aims to deliver cytotoxic temperatures to neoplastic tissue.
• Challenges in hyperthermia treatment include non-uniform power absorption and variable tumor blood flow.
• Accurate temperature monitoring and control are crucial for effective hyperthermia.

Purpose of the Study:

• To evaluate an online minimum temperature estimation and control technique for conductive interstitial hyperthermia.
• To assess the accuracy, precision, and stability of this technique in patients with malignant brain tumors.
• To determine the feasibility of controlling hyperthermia despite dynamic changes in local blood flow.

Main Methods:

• Utilized conductive interstitial hyperthermia with multiple electrically heated catheters.
• Implemented an online control system estimating minimum tumor temperatures based on catheter power and temperature rise.
• Monitored temperatures using 12-16 independent sensors per patient in 22 patients undergoing 31 treatment courses.

Main Results:

• The online estimation and control technique accurately and precisely regulated local minimum tumor temperatures.
• Comparison of measured and estimated temperatures showed a mean difference of 0.0 +/- 0.4°C for sensors within 1.0 mm of the target location.
• The system demonstrated stability and effectiveness even with time-varying local blood flow.

Conclusions:

• The developed online technique provides accurate and precise control of minimum tumor temperatures during interstitial hyperthermia.
• This method offers a reliable approach for managing hyperthermia therapy, particularly in the challenging context of brain tumors.
• The technique's ability to adapt to changing physiological conditions enhances its potential for clinical application in cancer treatment.