1580 Betulia is a near-Earth asteroid which is notable for its triple-peaked optical lightcurve: It can exhibit three pairs of brightness minima and maxima per rotation, unlike most asteroids which exhibit only two. This suggests an interesting shape, but while lightcurve-based shape reconstruction provides a robust estimate of Betulia's convex hull, delay-Doppler radar images are required to delineate concavities (e.g., craters). I will present an analysis of the 2002 Arecibo radar experiment on Betulia, showing how delay-Doppler images, continuous-wave Doppler spectra, and lightcurve data can be synthesized to determine the target's shape and spin state. They also provide an estimate of the asteroid's size, enabling us to address discrepancies in past analyses as to whether Betulia is a small object with a lunar-like fine-grained regolith or else a larger object with only large rocks or bare bedrock at its surface.