Intermolecular Multiple Quantum MR Thermography

An accurate method for noninvasive temperature monitoring in vivo would be invaluable for hyperthermic cancer treatments [1]. These therapies selectively heat tumors with RF or microwave radiation, thereby bringing about enhanced drug delivery (up to 30-fold), inhibited cell repair, and even cell death [2]. Unfortunately, this promising treatment has been stymied by the inadequacy of current methods to map temperature in vivo. Conventional magnetic resonance (MR) temperature maps are easily distorted, and provide only a relative measurement of the temperature. Instead we propose a physically different method based on the detection of water-fat iZQCs (intermolecular Zero Quantum Coherences) which produce an absolute temperature map and are insensitive to other distorting factors [3]. Novel but simple modifications to the pulse sequence allow us to isolate the relevant signal, and early applications demonstrate an order of magnitude improvement of temperature accuracy, both in vitro and in vivo.