Immobilization devices for radiation therapy

A method of immobilizing a subject during a radiation therapy procedure, the method comprising:

• providing an immobilization device, the immobilization device comprising:
• a conformal shell layer having a first side shaped to conform to an anatomical region of the subject;
• a rigid lattice structure extending outwardly from a second side of the conformal shell layer, the rigid lattice structure dividing an exposed portion of the second side of the conformal shell layer into a plurality of thin cellular regions and conferring structural rigidity to the conformal shell layer;
• employing the immobilization device to immobilize the anatomical region of the subject such that the first side resides adjacent to the anatomical region of the subject and such that the rigid lattice structure is disposed in a beam-facing orientation;
• and
• while immobilizing the anatomical region of the subject, performing the radiation therapy procedure, wherein the plurality of thin cellular regions exhibit a locally reduced bolusing effect, facilitate a reduction in surface dose delivered to the subject.