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US 4,733,653 AGranted
Radiotherapy apparatus
AssigneeThe Ontario Cancer Institute
InventorsPhilip K. M. Leung, Henry P. J. Webb
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AssigneeThe Ontario Cancer Institute
InventorsPhilip K. M. Leung, Henry P. J. Webb
Estimating the term…
In radiotherapy use is made of apparatus of the type in which a chain of balls comprising radioactive balls and inert spacer balls is moved pneumatically to and from an applicator tube within the patient, the spacer balls are made of a material such as nylon which is softer and less dense than the radioactive balls, and is radiographically transparent. This reduces wear and tear on the radioactive balls and facilitates control of dosage and monitoring of the treatment. The balls are sorted after use by means of a radiation detector. The ball chain has a large diameter end ball of ferromagnetic material, which blocks air flow through the applicator when correctly located therein, and whose position can be verified by an induction coil. By assembling and storing the chain in a storage tube having two air inlets, respectively above and below the end ball, and choking the lower inlet, air may be selectively applied to the inlets to expel the chain from the storage tube either with its end ball for transport to the applicator tube, or without its end ball for sorting. Use of the lower inlet alone enables pressure retaining the chain in the applicator to be maintained only in the absence of air flow through the applicator tube, thus enabling malfunctions to be detected.
In a system for intracavitary radiography comprising a chain of radioactive balls separated by non-radioactive spacer balls, an applicator tube, means to transport the balls pneumatically through a tube to and from the applicator tube, and means to sort the balls from the chain into radioactive and spacer balls, the improvement wherein the ball chain comprises a plurality of radioactive balls separated by non-radioactive spacer balls of radiographically transparent material of lower density and surface hardness than the radioactive balls, whereby battering of the radioactive balls by the spacer balls is avoided, and the spacer balls are distinguished from the radioactive balls by lack of radioactivity.
Radiotherapy treatment apparatus comprising a storage, sorting and assembly system containing radioactive balls and non-radioactive spacer balls of radiographically transparent material of lower density and surface hardness than the radioactive balls, the system including a sorter comprising a radiation detector, means to transport the balls past the radiation detector, and means receiving the radiation detector output and operative to divert the balls into different ball storage compartments depending upon whether or not the radioactive detector output exceeds a predetermined threshold, an assembler comprising means for selectively and successively releasing balls from said ball storage compartments into a ball chain store to assemble a ball chain of predetermined length, means for pneumatically conveying a ball chain between the ball chain store and a remote applicator tube for location within the body of a patient, and means for pneumatically conveying a ball chain from the ball chain store to the sorter.
Dependencies are inferred from the claim text.