High resolution multi-slice-dosimetry by means of T1 and T2 selective NMR-microscopy on polymer-gels

Along with the development of spatially selective irradiation schemes for tumour treatment the demands for high spatial resolution in dosimetric imaging increased. We demonstrate the possibility to obtain quasi 3D (multi slice) dose profiles at microscopic resolutions by means of T2 and T1 MR-microscopy on bis-acryl-amid-nitrogen-gelatin (BANGTM) gels. We achieved voxel sizes down to 195x195x1000 μm3. The high spatial resolutions are obtained on a high field (3T) whole body MR scanner (BRUCKER MEDSPEC 30/80, Ettlingen, Germany) upgraded by a MR-microscopy unit consisting mainly of a strong gradient system and a small r.f. resonator as detection unit. Parameter selective T2-images are obtained by a CPMG multi-echo sequence. The applicability to steep dose distributions, as present in a γ-knife two-collimator irradiation scheme, is shown. (author)