A method for medical imaging executed by an apparatus including a processor includes determining a start block of volume rendering based on respective maximum values of blocks positioned on a path of a light beam; acquiring a value of the light beam based on first sampling values acquired by sampling the start block; setting a processing order for remaining blocks positioned on the path of the light beam based on respective distances between the start block and the remaining blocks; determining whether a next block, according to the processing order, is to be processed, by comparing a maximum value of the next block with the value of the light beam; and comparing second sampling values acquired by sampling the next block with the value of the light beam and updating the value of the light beam according to a comparison result, in response to the maximum value of the next block being greater than the value of the light beam.