Phantoms for use in calibrating a dual energy imaging system and methods for their use. The phantoms include a body having at least first and second portions arranged in a through-thickness direction of the body. The first portion defines an anterior surface of the body and contains a first material simulating soft tissue and a second material simulating bone. The second portion contains a third material simulating lung tissue and at least a first object embedded in the third material and formed of a fourth material simulating tumor tissue. The first and second portions of the body are configured such that the second material in the first portion superimposes the first object in the second portion in the through-thickness direction of the body relative to the anterior surface thereof.
