Beam Delivery | Treatment Rooms
One decision required in building a new PT facility is the number and type of beam delivery rooms to build. In general, one can select various combinations to suit the anticipated patient demand and uses of the proton beam. In theory, the number of beam delivery rooms in a PT facility is unlimited from a technical standpoint.
From a practical view, oncology providers with PT experience have learned that, beyond 5-6 treatment rooms per accelerator, the logistics of beam scheduling introduces demand conflicts and unacceptable waiting times inside the treatment room. Primarily for this reason, typical configurations include 3-5 gantries and 1-2 fixed beams. Fixed Beam rooms can be designed for Ocular treatment, Intracranial and Head & Neck treatment, and Research with the proton or ion beam.
Similar to X-ray radiotherapy, the gantry is the movable portion of the beam transport. It is an isocentric rotating structure. On it is mounted a section of the beam transport line and the nozzle. The Gantry provides the radiation oncologist with the flexibility to treat patients with the optimal beam arrangement, from all angles.
Gantry Room |
As with X-ray radiotherapy, the Gantry is the movable portion of the beam transport. It is an isocentric rotating structure housed within a stationary gantry structure. A section of the beam transport line and the nozzle are supported by the rotating Gantry.
The Gantry provides the radiation oncologist with the flexibility to treat patients with the optimal beam arrangement, from all angles.
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The gantry structure is designed to minimize interference with the beam delivery system, provide maximum access to the patient, and maintain the isocenter position to within a sphere of radius 1 mm under all operating conditions, including all orientations, of the gantry. This is done by constructing the stiffest possible frame while at the same time minimizing the mass that the gantry bearings must carry.
To meet the precise tolerance specifications required in particle therapy, a completely new structure design using truss and shell elements was developed by IBA – having gained experience with previous designs which were subject to a degree of torsional deformation.
A simple rotating seal couples the moving portion of the beam transport tube to the stationary portion leading to the gantry, transporting the particle beam into the treatment room.
The Gantry has rollers equipped with friction-based drive motors for smooth and quiet operation, and designed to stop within ±0.25° of a pre-selected angle. Angular orientation is monitored and interlocked for high accuracy and safety.
The drive electronics are in communication with the control computer and an operator hand pendant. In no case will the gantry move unless the operator in the treatment area holds down a button on the hand pendant. Releasing the button at any time stops the rotation. In addition, the hand pendant has an emergency stop button that locks the brakes to stop rotation as fast as possible. Once the programmed position is reached, the operator can make fine adjustments.
This advanced and high-precision Gantry design is one of the many benefits of working with the world leader in particle therapy – IBA.
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