MRI dosimetry: A fast quantitative MRI method to determine 3D absorbed dose distributions

RATIONALE AND OBJECTIVES. Magnetic resonance imaging (MRI) techniques seem to be very promising for 3D dosimetry studies, but long imaging acquisition time limits their use, A new fast T1 mapping protocol, easy to implement o n a conventional MR imager, has been used to determine dose distributions o n Fricke gels. METHODS. The method has been tested on manganese chloride (MnCl2 doped ferr ous gelatin gels, The T1 measuring times range from I minute 40 seconds to 3 minutes 30 seconds for a 256 x 256 matrix image. RESULTS. The two- and three-dimensional profiles agree with those obtained with conventional dosimetry techniques lion chambers), The precision and th e spatial resolution principally depend on the signal-to-noise ratio of the used imaging RF coil. For example, for a surface coil, the accuracy is abo ut 2.5% with a 1.56 mm spatial resolution. CONCLUSION. These preliminary results support the feasibility of the propos ed technique for accurate MRI dosimetry studies and also have potential for various clinical quantitative MRI applications.