Proportional attenuation of radiation in brachytheraphy treatment

摘要

Attenuating masks for selective attenuation of radiation, particularly from an x-ray source in brachytherapy, employ materials having atomic number in a specific range, so as to attenuate radiation dose intensity generally proportionally through a range of distance from the source. Some preferred attenuation materials are silver and molybdenum. A set of small masks can be provided for a particular design of catheter that holds a radiation source, each mask having a size and shape to define a different solid angle of masking, so that in a brachytherapy procedure, sensitive tissue such as bone or skin can be protected by proper selection of and positioning of the attenuating mask, to reduce the dose intensity to that tissue.

主权项

1. A catheter apparatus with x-ray radiation attenuation for selectively protecting sensitive tissues during irradiation of adjacent tissues of a living patient, comprising:
a catheter carrying a source of ionized radiation, generally in the range of about 40-60 kV, and a catheter element associated with the catheter, said catheter element disposed about said catheter, and an attenuator mask positioned on the catheter element and adjacent to the source, positioned to attenuate a portion of the spatial radiation emission pattern surrounding the source, the mask comprising an attenuating material having atomic number in the range of about 40 to about 53, whereby the mask attenuates the x-ray radiation by a desired factor essentially consistently throughout the range of said portion of the spatial radiation emission pattern, a manipulator for independently controlling the catheter element and catheter, said catheter element comprising an outer sheath, and said manipulator including a first manipulator for controlling the catheter and a second manipulator for controlling the sheath, at least one of said manipulators including a control mechanism for controlling both axial translation and rotation.