The DWMRI/MRS Glioma Imaging Protocol Lars Ewell University of Arizona Medical Center Department of Radiation Oncology Faculty Research Meeting 6/23/08

2 The DWMRI/MRS Glioma Imaging Protocol I.Introduction II.Radiation Induced Necrosis/Disease III.Imaging Protocol IV.Initial Data V.Conclusion

The DWMRI/MRS Glioma Imaging Protocol: Introduction Designed to study whether or not Diffusion Weighted MRI and Magnetic Resonance Spectroscopy (MRS) can differentiate between radiation necrosis and recurrent disease. Enrolled first patient 3/23/07. See 3

Patients eligible to enroll if they have a reasonable risk of suffering from RIN. 4 DWMRI/MRS Protocol: Enrollment Criteria 1) Kumar et al., ‘Malignant Gliomas: MR Imaging Spectrum of Radiation Therapy and Chemotherapy Induced Necrosis of the Brain After Treatment’, Radiology, 217, 2, November Published data 1 indicate that patients receiving a dose of  60Gy in 30 Fx have between a 5 and 24% chance of developing RIN.

Imaging Protocol: Enrollment Criteria Biological Equivalent Dose (BED) used to determine enrollment criteria for hypo- fractionation and SRS. 5 BED = nd(1 + ) with n the number of fractions, d the dose,  and  the linear quadratic constants. 5 x 6Gy required for hypo - fractionation, 21Gy for SRS.

6 Imaging Protocol: Enrollment Criteria Radiation TypeNumber of Fractions Minimum Radiation (Gy) SRS121 Hypo-fraction530 Normal Fraction3060 Re-treatmentvaries

7 Imaging Protocol: Scan Data Three MRS slices, one cm/slice: One centered on lesion, one superior and one inferior. Voxel size ~ 4cc. Set of three ‘diffrad’ DWMRI scans with b-values: 0, 520 and 850 s/mm 2. Set of two ‘echo planar’ DWMRI scans with b-values: 0, 1000 s/mm 2. Scan time approximately < one hour.

Protocol Patient Events CharacteristicNumber of Patients Deceased7 Withdrew3 One Scan16 Two Scans9 Three Scans3 Four Scans2 Biopsy1