Methods and apparatus for determining radiation doses based on phantom matching are disclosed. An example apparatus includes memory to store computer readable instructions; and processor circuitry to execute the computer readable instructions to prompt a capture of a second scout image when at least one of: (A) a first anatomical landmark in a first scout image of a first scout image file does not include an organ, (B) a first set of dimensions of the first anatomic landmark in the first scout image cannot be determined, or (C) the first set of dimensions are outside of a predefined range; and calculate a radiation dose for an organ in a second anatomical landmark of a second scout image file corresponding to the second scout image.