Tumour perfusion assessment during regional hyperthermia treatment: Comparison of temperature probe measurement with H215O-PET perfusion

Purpose: Hyperthermia treatment might increase tumour oxygenation and perfusion, as has been reported for experimental tumours. The present study was performed to investigate this hypothesis in patients undergoing regional hyperthermia treatment.

Methods: Thirteen patients with primary or recurrent pelvic tumours were included in this study. Prior to and up to one hour after regional hyperthermia, perfusion was quantitatively determined by H₂¹⁵O-PET. The fused CT-PET images were used to extract tumour time-activity curves and to identify the catheter position. Perfusion was calculated from the total tumour time-activity curves and for the time-activity curves at the catheter site. Additionally, perfusion was calculated from the temperature-time curves measured using temperature probes.

Results: Perfusion values calculated using H₂¹⁵O-PET and those deduced from temperature probe measurements are significantly correlated with a correlation coefficient, R = 0.21. The perfusion values deduced from the temperature measured in a body cavity do not provide information about average tumour perfusion. Perfusion values deduced from the temperature are overestimated for very poorly perfused tissues and underestimated for highly perfused tissues.

Conclusions: Temperature measurement during hyperthermia may allow only determination of intermediate perfusion values.