Systems and methods for standardizing target lesion selection within cross-sectional medical images can include the acts of: (i) sending a plurality of cross-sectional images to a user device, where each cross-sectional image is a cross-sectional slice of digital medical image data captured at a first timepoint from a radiologic device; (ii) receiving a user input identifying a set of pixels corresponding to a target lesion within a cross-sectional image of the plurality of cross-sectional images; and (iii) generating a target lesion location file that includes a precise anatomical location of the cross-sectional image and a pixel location of the target lesion within the cross-sectional image. The systems and methods can additionally include the act of causing a digital marker to be displayed on the cross-sectional image and on each analogous cross-sectional image captured at a later timepoint.