Planning target volumes for high grade gliomas were similar at 3 Tesla and 1.5Tesla MR using a standard imaging protocols. However, in some patients, the 3T MR may reveal substantially smaller tumor volume due to inferior conspicuity of the lesion. These findings imply that while overall the radiation target volumes are comparable, there are differences in contrast-to-noise ratios (CNR) and signal-to-noise ratio (SNR) that lead to differences in individual patients. The 1.5T may be better for gaining conspicuity of the tumor ¹⁾.