To confirm breathing position, we placed an infrared marker [21, 22] on the diaphragm region with an abdominal pressure belt and observed the breathing pattern using a spirometer [13]. Accurate and reproducible fixation could be achieved using this device.

Breathing-related movement can be controlled by suppressing diaphragmatic movement as with an abdominal pressure board. Whether movement is restrained can be determined by observing tumor movement by fluoroscopy, and the strength of pressure applied by the board can be regulated accordingly.

In cases with a lesion in the lower lung field, diaphragm movement can be restrained by an average of more than 5 mm, and therefore the irradiation range can be minimized by reducing the movement of the tumor [15].

Depending on the case, breathing-related movement may be large when pressure is applied to the diaphragm region. Such movement may be controlled by applying abdominal pressure, but it may be necessary to apply oxygen inhalation as breathing tends to become relatively shallow with such treatment [7].

Then, I explain the function of the fixture with the change of the fixture of our facilities.

When we first began performing stereotactic body irradiation at our facilities during until 2007, we adopted the Stereotactic Body Frame (SBF) [1–6, 16] (Fig. 6.1) developed by the Swedish company Elekta with the cooperation of Karolinska Hospital in Stockholm.

We subsequently introduced the high-flexibility Body Fix [24, 25] (Fig. 6.3) for immobilization, which interfered little with the gantry and showed little dose absorption at our facilities.

Irradiation was carried out in patents under free-breathing conditions by dynamic tumor tracking irradiation [18–23]. It became clear that immobilization techniques with which it was easy to observe movement from each direction in fluoroscopy images were required.

This method is available for liver and pancreatic cancer, and clinical results have been reported for a therapeutic method using SBF adapted for body irradiation [1–6].

Figure 6.4 shows immobilization SBF for use in SBRT of the trunk region. The size and shape of SBF with a minimum opening of 550 mm are designed for CT, magnetic resonance (MR), and positron emission tomography (PET). The frame wall is composed of glass fiber and white birch plywood, low-density materials that keep attenuation of the beam to a minimum [16]. There is an atmospheric layer and a vacuum pillow inside the frame. CT level of pillow part is almost equivalent to atmosphere. This part can be molded along the body of the patient. Furthermore, a CT indicator made of polymethyl methacrylate (PMMA), which can read the three-dimensional coordinates on CT, is embedded within the inner wall of the frame, and a Z-axis scale made of plastic is attached to the outer wall. A XY- axis scale for positioning is shaped arch on a frame, and made of aluminum, which can remove during irradiation. There is a level control that made of rubber bag in unilateral of the frame base. This function can control to coordinate the position of horizontal direction with adjusting of air pressure. In addition, as other appliances, laser pointer can be set for skin marker on chest wall (Fig. 6.5a), and the pressure board can be set to control breathing movement on upper abdomen.

The stereotactic body frame (SBF) has many functions that were developed for stereotactic body radiation therapy (SBRT) with a high degree of reproducibility. We introduced Body Fix in place of SBF in our facilities in 2007 as it has a number of advantages in that it is composed of material with little dose absorption, its structure interferes little with the gantry, and it has high spatial flexibility. For dynamic tumor tracking irradiation, the patient is irradiated under free-breathing conditions. Therefore, a fixation device that facilitates observation of the movement of a marker and the lesion in fluoroscopy images during irradiation or verification was required. The fixation device requires precision, and a function to reproduce the setup position of bone exactly is required. Alignment requires use of a skin mark and an adjustment appliance prior to use. Bone position can be reproduced with greater precision and within a shorter time using image-guided radiation therapy (IGRT) compared to previous methodologies. The position revision in verification enabled automatic reproduction of a position and a tilt with accurate six-axial (X, Y, Z, Roll, Pitch, and Yaw) revision of couch position. However, during setup, it is necessary to reproduce torsion and flexure of the body in a minimum requirement. Accordingly introduction of IGRT, the purpose of the fixture and the necessary matter changed. Use of a fixation device such as Body Fix, which is simple and shows little absorption, is effective for positioning verification using fluoroscopy, such as dynamic tracking irradiation or irradiation synchronized with respiration.