Investigative radiology
-
Investigative radiology · Dec 2008
MR characterization of mild hyperthermia-induced gadodiamide release from thermosensitive liposomes in solid tumors.
Thermal dose in tumor tissue is a key factor for regional hyperthermia (HT) combined with chemotherapy and for drug delivery using thermosensitive liposomes (TSL). It influences therapy outcome, affects the accumulation of liposomes, and triggers the content release from TSL in the target tissue. For the development and clinical application of TSL, noninvasive visualization is of critical importance. For this purpose, TSL loaded with MRI contrast agent (CA) have been developed. With increase in temperature, the CA is released from TSL at the phase transition temperature Tm resulting in a relaxation time change, which allows MRI monitoring. The purpose of this study was to examine the feasibility of an in vivo application and MR characterization of Gd-DTPA-BMA-loaded phosphatidylglyceroglycerol-TSL (Gd-TSL) at mild HT conditions in tumor tissue using a clinically relevant setting. ⋯ HT-induced CA release from Gd-TSL was monitored and characterized by MRI after i.v. injection in tumor-bearing mice. Higher temperatures resulted in higher signal changes. Immediately after i.v. injection, heated tumor tissue was distinguishable from unheated tumor tissue. The Gd-TSL appears to be suitable for MR monitoring of HT tumor treatment in a clinical MRI setting independent of field strength.