Disclosed are a radiation imaging system, an image processing device, and a non-transitory computer-readable recording medium having an image processing program recorded thereon which facilitate the confirmation of a positional relationship between an object of interest and a biopsy needle. A control unit of a console reconstructs a projection image obtained by tomosynthesis imaging to generate a tomographic image parallel (an x-y-axis direction) to an imaging surface in a state where a needle is inserted into a breast, and specifies an image of an object of interest from the tomographic image. The control unit generates a sectional image which includes the specified image of the object of interest and an image of the needle and intersects the imaging surface. The control unit generates an image of the needle from the projection image, synthesizes the generated image of the needle into the sectional image while aligning, and displays the sectional image.