Synchrotron microbeam radiation therapy (MRT) has shown promise in pre-clinical studies on tumour-inoculated rodents. MRT is based on observations that normal tissue displays a remarkable resistance to necrosis when irradiated with parallel, thin slices of X-rays. Additional findings suggest that tumour tissue is destroyed by MRT at doses that leave surrounding normal tissues relatively undamaged. The biological effects of MRT are not well understood, and are complicated by difficulties in measuring the MRT radiation doses delivered to the tissue. The lack of a suitable method to measure the dose distribution from an array of microbeams has hampered progress towards clinical use of MRT. The aim of this invited presentation is to discuss physical and biological approaches to measuring the unique, absorbed dose distribution from synchrotron MRT.