Читать книгу Leksell Radiosurgery - Группа авторов - Страница 60

MR spectroscopy (MRS) is a technique that can detect proton metabolites in tissue and provide information regarding tumor proliferation, cell membrane breakdown, neuronal activity, and tumor necrosis [7]. The most commonly detected metabolites include choline-containing compounds, creatine, lactate, lipid, and N-acetylaspartate (NAA). Spectroscopic images are obtained with either 3-dimensional or 3-dimensional means of acquisition. This is achieved by mapping the concentration of each of the compounds within voxel sizes of approximately 1 cm³. Malignant tumors are characterized by an elevated choline to NAA ratio due to greater cell membrane phospholipid turnover from increased tumor proliferation as well as decreased NAA compared to the normal brain [8]. We imported MRS images and co-registered these with stereotactic images and used them for dose planning in cases of recurrent glioblastoma (GBM; Fig. 4).

Fig. 4. MRS of GBM (left) and an MRS map projected on axial MR images (right) that can be used for radiosurgery dose planning of malignant tumors. A choline to NAA ratio of more than 2 is shown as red.