# FFF.1.2.2 Patient Position

## FFF.1.2.2.1 Table Description

The table coordinates are defined in the section C.8.7.4.1.4 of PS 3.3.

The table coordinate system is represented as: (O t , X t , Y t , Z t ) where the origin O t is located on the tabletop and is arbitrarily defined for each system.

[pic]

Figure FFF.1.2-3Table Coordinate System

## FFF.1.2.2.2 Options for Patient Position on the X-Ray Table

The position of the patient in the X-Ray table is described in the section C.7.3.1.1.2 of PS 3.3.

The table below shows the direction cosines for each of the three patient directions (Left, Posterior, Head) related to the Table coordinate system (X t , Y t , Z t ), for each patient position on the X-Ray table:

 Patient Position Patient left direction Patient posterior direction Patient head direction Recumbent - Head First - Supine (1, 0, 0) (0, 1, 0) (0, 0, 1) Recumbent - Head First - Prone (-1, 0, 0) (0, -1, 0) (0, 0, 1) Recumbent - Head First - Decubitus Right (0, -1, 0) (1, 0, 0) (0, 0, 1) Recumbent - Head First - Decubitus Left (0, 1, 0) (-1, 0, 0) (0, 0, 1) Recumbent - Feet First - Supine (-1, 0, 0) (0, 1, 0) (0, 0, -1) Recumbent - Feet First - Prone (1, 0, 0) (0, -1, 0) (0, 0, -1) Recumbent - Feet First- Decubitus Right (0, -1, 0) (-1, 0, 0) (0, 0, -1) Recumbent - Feet First -Decubitus Left (0, 1, 0) (1, 0, 0) (0, 0, -1)