Gantry facility

In the Bronowice Cyclotron Centre protons are produced and accelerated to appropriate energies in the isochronous cyclotron Proteus C-235 (IBA, Belgium). Leaving cyclotron protons have clearly defined energy equal to 230 MeV. In the proton radiotherapy, energy (which translates to the proton range) should be adjusted to the tumor location. For this purpose the energy degrader is used. It absorbs part of the energy allowing the irradiation of shallowly located tumors. The proton beam is transported to the treatment room using vacuum tube with dipole and quadrupole magnets and set of collimators. It control the energy distribution and give the right direction of the proton beam to deliver it to the selected therapy room.

In order to irradiate the tumor that are in different locations of the patient body is required to provide a solution which allows provide the beam from different directions. The movable beam (known as ‘gantry’) is a technique that allows the treatment angle to 360deg. The gantry is a movable arm form as a steel construction, carried out the bending magnets, weighing 100 tons and 10 m diameter. Despite of this huge extent, the proton beam is delivered to the treated area with precision better than 1 mm.

During the radiotherapy session patient is lying down on the treatment table, which is inserted to the robotic arm to allow its movements in the 6 axis. This allows for very precise positioning of the patient before irradiation. Additionally gantry is equipped with set of two X-ray tubes and graphic panels. Before irradiation set of the X-ray images of selected part of patient body on the basis on which the precise positioning is realized. The gantry room is also equipped with an Align RT camera units for patient positioning and proton beam gating during the radiotherapy. The gating involves tracking breathing movements on the patient chest and automatic pause and restart during the irradiation.