Permits check of:

• Optical distance indicator (over a 15 cm range)
• Collimator and central crosshair
• Head rotation and pitch
• Isocenter variation
• Side lights and optical back pointer
• Light field vs radiation field

Tel-Align consists of a rectangular plastic base with a removable vertical scale. The top surface of the base contains lead markers that form a square (10 cm x 10 cm) for visualization on film. A crosshair in the center of the square lines up with two additional sets of crosshairs, one on each outer edge of the base.

After the machine field size (10 x 10 cm) has been set, the table height should be adjusted until the base surface is at the isocenter distance. The collimator rotation angle is set at 0°. When positioned properly, the edges of the light field should coincide with the inscribed square. The field center should intersect the center crosshair and the side lights should agree with the corresponding crosshairs at the edges of the base.

The vertical scale is placed on the base to check the optical distance indicator, or a film can be placed under the base to check the light field versus the radiation field. By rotating the gantry angle at ± 90°, the isocenter variation and optical back pointer are also checked.

Specifications

Base: 5.51” W x 7.09” D x 0.79” H
Vertical Scale: 7.09” H
Weight: 2 lbs