Nonanthropomorphic Dynamic Water Phantom for Spot Scanning Proton Therapy

The capabilities of a compact nonanthropomorphic dynamic water phantom for spot scanning proton therapy are presented. This phantom simulates the intrafractional motion of a tissue-equivalent target in water in various modes. The design of the phantom is optimized for fixed horizontal beam setups without gantry. The phantom targets are compatible with standard dosimetry equipment, such as ionization chambers and dosimetry films. The dynamic phantom is characterized by small dimensions and weight, low cost, and wide functionality with the possibility of its refinement; it is also easy to use. The phantom can be used for both research purposes and routine quality control procedures in proton therapy of intrafractionally moving tumors.