Purpose: To construct a total body irradiation (TBI) apparatus that will support a patient lying in the decubitus position at a specified SAD for high dose treatment protocols. The design allows for the use of lung blocks to reduce the risk of radiation pneumonitis while minimizing dose perturbations to the non-shielded region of the beam and maintaining patient comfort.
Methods: A new TBI frame was designed to fit around a dedicated stretcher cart which lifts the patient to isocenter height while supporting the patient in either left or right decubitus positions.
Results: A TBI frame on wheels was constructed from extruded aluminum components to support a 222cm by 90cm acrylic beam spoiler (9.53mm thick). The lung block holder consists of two independent acrylic plates with two slots for mounting the lung blocks. These plates are attached to two parallel vertical carbon fiber “W” profile rails by two polyethylene glides with nylon thumbscrew locks. The vertical rails slide horizontally along the beam spoiler frame. This design allows for efficient 2D translation of each individual lung block while minimizing dose perturbations. The base pad and decubitus supports are constructed of cross-linked polyethylene (XLPE) foam to provide both structure and graduated support for the patient. Each pad is covered in a durable polyurethane / silicone blend material to facilitate high-level disinfection of the surfaces between patients. The decubitus support is secured to the base pad using a system of four carbon-fiber nesting tubes.
Conclusion: This new TBI apparatus meets the needs for our institution to implement high dose TBI protocols while keeping patients in a more comfortable position than current commercial solutions would allow and at a more reasonable price point of approximately $7500 USD.
TBI, Linear Accelerator, Patient Positioning