Cranial 4Pi Immobilization

The Cranial 4Pi Immobilization is a patient positioning and immobilization system for radiotherapy and radiosurgery of the cranial and head & neck regions. It consists of overlays, headrests, inlays, masks, wedges, and spacers that work together to position and stabilize a patient's head during radiation treatment in CT and linear accelerator environments.

The subject device adds a new Cranial 4Pi Headrest Platform with wedges (5° and 10° angulations), a 20 mm spacer, and two head support shapes (standard and wide) to treat patients with kyphosis or special body indications. It also introduces a Cranial 4Pi Stereotactic Mask 3.2 mm variant with a thicker top sheet (3.2 mm instead of 2 mm) for improved stability. All components use polyurethane-coated foam materials.

ISO 10993-10 (sensitization testing), ISO 10993-23 (irritation testing), ISO 10993-2 (biocompatibility endpoints), IEC 60601-1 (mechanical verification), and compatibility testing with ExacTrac Dynamic 2.0.

The subject device performs the same immobilization function and is indicated for the same medical conditions (cranial and head & neck radiotherapy/radiosurgery) as the predicate K202050. The added headrest platform, wedges, spacer, and improved mask thickness are incremental design enhancements using the same materials and interfaces. Biocompatibility testing confirms safety, mechanical and dosimetry tests confirm functional equivalence, and usability testing with seven clinical participants demonstrated that the device operates safely with similar effectiveness to the predicate and comparable solutions.