What Happens in The Treatment Room During Each Treatment?
Once the treatment position is verified by a physician, the treatment is given. After changing into a gown, the patient enters the treatment room. The patient either lies in the mould or sits in a chair and is fitted with the mask. With laser beams as guides, the patient is moved to a position that is usually within half a centimeter (less than a quarter of an inch) of the calculated optimal position. To make the position more precise, the radiation therapy technologist obtains several low-power diagnostic radiographs or digital images. Distances from various bone landmarks to the isocenter are measured on these daily images. These are compared to identical measurements made on computer-generated films based on the planning CT scan.
Usually, it is necessary to move the patient a few millimeters to make the daily position conform exactly to the prescribed treatment position. These measurements and movements are performed by radiation therapy technologists.
After any necessary movements have been made, the patient's specially created treatment devices are loaded into the beam line. All of these devices are identified by an individual bar code, which must be scanned by a laser scanner (similar to those found at a supermarket). A match must be made before the computer will permit a treatment to begin. This system minimizes the risk that a patient may be treated with another patient's unique devices.
Next, the technologists and physician retire to a control room to begin treatment. The control room is located just outside of each treatment room. Protons enter the room as a series of discrete spills or pulses, which (like x-rays) cannot be seen or felt. After the prescribed radiation dose has been delivered, the computer shuts off the proton beam. The technologists then re-enter the room, and the patient is assisted from the mould or mask and changes out of the gown.