A method to convert MRI images of temperature change into images of absolute temperature in solid tumours.

Published

Journal Article

During hyperthermia (HT), the therapeutic response of tumours varies substantially within the target temperature range (39-43 °C). Current thermometry methods are either invasive or measure only temperature change, which limits the ability to study tissue responses to HT. This study combines manganese-containing low temperature sensitive liposomes (Mn-LTSL) with proton resonance frequency shift (PRFS) thermometry to measure absolute temperature in tumours with high spatial and temporal resolution using MRI.Liposomes were loaded with 300 mM MnSO(4). The phase transition temperature (T(m)) of Mn-LTSL samples was measured by differential scanning calorimetry (DSC). The release of manganese from Mn-LTSL in saline was characterised with inductively coupled plasma atomic emission spectroscopy. A 2T GE small animal scanner was used to acquire dynamic T1-weighted images and temperature change images of Mn-LTSL in saline phantoms and fibrosarcoma-bearing Fisher-344 rats receiving hyperthermia after Mn-LTSL injection.The T(m) of Mn-LTSL in rat blood was 42.9 ± 0.2 °C (DSC). For Mn-LTSL samples (0.06 mM-0.5 mM Mn(2+) in saline) heated monotonically from 30 °C to 50 °C, a peak in the rate of MRI signal enhancement occurred at 43.1° ± 0.3 °C. The same peak in signal enhancement rate was observed during heating of fibrosarcoma tumours (N = 3) after injection of Mn-LTSL, and the peak was used to convert temperature change images into absolute temperature. Accuracies of calibrated temperature measurements were in the range 0.9-1.8 °C.The release of Mn(2+) from Mn-LTSL affects the rate of MR signal enhancement which enables conversion of MRI-based temperature change images to absolute temperature.

Full Text

Duke Authors

Cited Authors

  • Davis, RM; Viglianti, BL; Yarmolenko, P; Park, J-Y; Stauffer, P; Needham, D; Dewhirst, MW

Published Date

  • September 2013

Published In

Volume / Issue

  • 29 / 6

Start / End Page

  • 569 - 581

PubMed ID

  • 23957326

Pubmed Central ID

  • 23957326

Electronic International Standard Serial Number (EISSN)

  • 1464-5157

International Standard Serial Number (ISSN)

  • 0265-6736

Digital Object Identifier (DOI)

  • 10.3109/02656736.2013.790091

Language

  • eng