We use various devices to manage treatment precision.
1. “ExacTrac” Image Guided System (Infrared System/X-ray System)
Markers that reflect infrared light are applied around the irradiation location on the patient. The patient positioning is confirmed before irradiation with an infrared camera so that the same position is ensured for irradiation each time. Our clinic also uses an ExacTrac X-ray system for positioning. Markers are applied on a plastic sheet called a shell molded to the shape of individual patients. We do not directly apply marker stickers or draw markers on the patient’s skin.
2. “iBeam Couchtop” Robotic Couch System
The device is equipped with a state-of-the-art automatic positioning couchtop. Conventional treatment devices allow only lengthwise, widthwise, and vertical movement. The couchtop at our clinic can adjust the angles in each rotational direction. We have fixtures so that the patient can lie on the couchtop in the same position each time. This enables external positioning. However, it is still difficult to position internal structures of the body. The ExacTrac X-ray system (1) at our clinic automatically analyzes the difference from the position determined in the CT imaging used to formulate the treatment plan based on the X-ray image information obtained so that irradiation is applied exactly to the same location of the tumor each time. The system can automatically move the couchtop to adjust the difference.
3. “Type-S” Head and Neck Immobilization Device
Our clinic uses a Type-S immobilization device appropriate for IMRT (Intensity Modulated Radiation Therapy) for irradiation of the head and neck. A warmed plastic shell is used to mold to the shape of the patient. This is different from conventional fixtures that buckle up the patient, it is made of one sheet that covers the patient from the head to the shoulders, and makes positioning highly reproducible. Infrared markers are applied to the surface of the Type-S for positioning. Markers are not drawn on the patient’s skin.
4. “HipFix” Type Truncal Immobilization Device
Our clinic uses a HipFix immobilization device appropriate for IMRT (Intensity Modulated Radiation Therapy) for irradiation of the body trunk. A Vac-Lok cushion (5) is concurrently used for immobilization. A Vac-Lok cushion is used to mold to the back and hips. A warmed plastic shell is used to mold to the thorax and abdomen. Infrared markers are applied to the shell for positioning. Markers are not drawn on the patient’s skin.
5. Vac-Lok Vacuum Cushions
The Vac-Lok patient fixation device is a cushion made from a strength-reinforced mat filled with polystyrene beads. The cushion forms a custom mold of the anatomical contours of the patient’s hips and back when a vacuum is drawn, resulting in a fixation device customized to each patient. Once vacuum-formed, the cushion will retain its shape until air is let in again.