| Thermal therapy is widely used for the treatment of tumors such as uterine fibroid tumors. When heating the fibroid volume, continuous and fast temperature monitoring is required to limit the damage to healthy tissue. The phase component of the Magnetic Resonance (MR) image changes with heating; this phase change can be converted to temperature using a scaling parameter. One plane alone can be imaged in the current treatments while monitoring the temperature during heating because of time limitations. This plane is usually prescribed at the focus of the transducer (focal plane) to cover the maximum heat deposition. However, the heat distribution is not limited to the focal plane only, which requires temperature monitoring in more than one plane. MUltiple Resolution along Phase-encode and Slice-select-dimensions (MURPS) was a method previously introduced [7] to produce a variable slice thickness in the z-direction and variable phase encodings in the y-direction. MURPS is implemented to address the need for very fast imaging of multiple planes. Because only a small portion of the field of view (FOV) has real clinical value in the thermotherapy of a large volume, the FOV can be reduced to image that portion and speed up the scanning. The MURPS method, combined with half reduced field of view (rFOV), can image three planes in the same time needed to image a single full field of view plane without MURPS. The proposed technique of MURPS with rFOV should have a significant advantage for monitoring thermal therapies and should provide more robust temperature control for current thermal therapy treatment procedures. |
