| 摘要 |
<p>A radiation field-shielding device is mounted on a collimator (4) in a radiotherapy apparatus. The collimator (4) is rotatable in a per se known manner about its axis and in its entirety about the horizontal axis of rotation of the radiotherapy apparatus for irradiating a patient lying on a treatment table. The device (5) comprises a housing (25) removably mounted on the collimator (4), and a holder (10) with radiation shield means (11) spaced from the collimator (4). The holder (10) is pivotable about a shaft (26) away from its position in front of the collimator (4) to a position at the side of the collimator (4), in which position the holder (10) is rotatable about a second shaft oriented towards the centre of the holder (10) and extending at right angles to the first shaft (26). In this manner, there is obtained, by two simple operations of rotation, a mirror inversion of the shield means (11) wihtout necessitating dismounting or shifting thereof. Rotation of the collimator (4) about its axis together with rotation of the rotary part (3) of the radiotherapy apparatus allows irradiation of the patient in opposite directions with the same shielding configuration.</p> |
