Radiation therapy apparatus with selective shielding capability
Brachytherapy applicators incorporate various forms of selective shielding devices for controlling the direction and intensity of radiation directed at a patient's tissue. In some forms the applicators include a retractable sheath, in some a series of retractable fingers. In other forms the applicator, having an inflatable balloon, has a shield which is retractable from a position adjacent to the balloon or retracted from the balloon, or a shield can itself be inflatable, separately or together with the balloon.
1 . A radiation brachytherapy applicator with directional shielding, comprising:
an applicator with a shaft capable of being positioned within a living patient, the shaft having a lumen within which is positioned an x-ray source, near a distal end of the applicator,
an inflatable balloon connected to the shaft of the applicator so as to be inflatable after insertion to provide an expanded volume around the x-ray source, with the shaft including a balloon inflation lumen, and
a radiation attenuating shield at the proximal end of the balloon, formed as part of the balloon and elastic so as to expand to form an increasing area of attenuation as the balloon is expanded, to shield radiation in the proximal direction and to form an increasing shielded volume proximal of the shield as the baloon is expanded.
2 . A radiation brachytherapy applicator with directional shielding, comprising:
an applicator with a shaft capable of being positioned within a living patient, the shaft having a lumen within which is positioned an x-ray source, near a distal end of the applicator,
an inflatable balloon connected to the shaft of the applicator so as to be inflatable after insertion to provide an expanded volume around the x-ray source, with the shaft including a balloon inflation lumen, and
a radiation attentuating shield on the shaft entirely proximal to the balloon, the shield being inflatable by an inflation fluid so as to shield radiation in the proximal direction to an increasing extent and over an increasing volume as the shield is inflated.
3 . (canceled)
4 . An applicator as in claim 2 , wherein the shield is inflatable separately from the balloon.
5 . An applicator as in claim 4 , wherein the shield comprises an inflatable torus mounted on the shaft for axial sliding movement, so as to be selectively inflatable and selectively positionable relative to the source and balloon.
6 . A radiation brachytherapy applicator with directional shielding, comprising:
an applicator with a shaft capable of being positioned within a living patient, the shaft having a lumen within which is positioned an x-ray source, near a distal end of the applicator,
a radiation attentuating shield mounted slidably on the exterior of the shaft and limited to a path of sliding travel having a most distal position spaced proximally of the x-ray source, so as to shield radiation in the proximal direction, so that the shield is adjustable as to distance from the x-ray source.