DOS BULLETIN - Dansk Ortopædisk Selskab

2010-378_DOS nr. 3 2010 29/09/10 10:08 Side 132
The effect of Mild Hyperthermia on Extravasation of
USPIO Particles in a murine tumor model
Claus Tvedesøe, Søren, Bach, Michael Horsman, Esben Larsen,
Steffen Hokland, Cody Bünger
Orthopaedic research laboratory, Aarhus University Hospital, Department
of Clinical Experimental Oncology, Interdisciplinary Nanoscience
Center, MR-research center, Aarhus University Hospital
Background: Ultrasmall Iron Oxide (USPIO) particles have superparamagnetic
characteristics. It is possible to attach various compounds to
USPIO particles such as chemotherapy and silencing RNA sequences.
Mild hyperthermia can disrupt tumor vessel endothelial barrier allowing
USPIO particles to diffuse into the interstitial space of tumor.
Purpose: In this study we have investigated the effect of various lengths
of localized mild hyperthermia on the extravasation of i.v injected
USPIO particles in a murine tumor.
Methods: Tumor model Mammary carcinoma tumors were grown in the
rear right foot of CDF1 mice. Hyperthermia Heat treatment was performed
locally by submerging the tumor bearing foot in a circulating
water bath at 41.5 °C. Animals were randomized into four groups 1,
USPIO particles only; 2, USPIO particles and 5 min of HT; 3, USPIO
particles and 30 min of HT and 4, USPIO particles and 60 min of HT.
N=9 in each group. Animals were MR scanned prior to injections and
after 90-, 390- and 1140 min.
Findings: Change in T2* in response to heating length shows a significant
difference between animals heated for 30- and 60 minutes compared
to animals heated for only 5 minutes and controls (p