Guided Radiation Therapy System

Abstract

<heading lvl="0">Abstract of Disclosure</heading> A system and method for accurately locating and tracking the position of a target, such as a tumor or the like, within a body. In one embodiment, the system is a target locating and monitoring system usable with a radiation delivery source that delivers selected doses of radiation to a target in a body. The system includes one or more excitable markers positionable in or near the target, an external excitation source that remotely excites the markers to produce an identifiable signal, and a plurality of sensors spaced apart in a known geometry relative to each other. A computer is coupled to the sensors and configured to use the marker measurements to identify a target isocenter within the target. The computer compares the position of the target isocenter with the location of the machine isocenter. The computer also controls movement of the patient and a patient support device so the target isocenter is co-incident with the machine isocenter before and during radiation therapy.

Description

Technical Field[0001] This invention relates generally to radiation therapy systems, and more particularly to systems and methods for accurately locating and tracking a target in a body to which guided radiation therapy is delivered.Background of the Invention[0002] Recent advances in radiation therapy are providing new avenues of effective treatment for localized cancer. These include three-dimensional conformal external beam radiation, intensity modulated radiation therapy (IMRT), and stereotactic radiosurgery and brachytherapy. These newer treatment modalities deliver greater doses of radiation to the tumor, which accounts for their increased effectiveness when compared to standard external beam radiation therapy.[0003] To achieve continued improvements in the management of localized cancers with radiotherapy, further dose escalation is necessary because a dose response relationship for radiotherapy exists for most cancers. However, with the increased dose of delivered radiation ...

AI Technical Summary

Benefits of technology

0009] Under one aspect of the invention, a system and methods are provided for accurately locating and tracking the actual position of a target within a body in preparation for and during radiation therapy. In one embodiment, the system is usable with a radiation delivery source that delivers a selected dose of radiation to the target in the body when the target is positioned at the machine isocenter of the radiation delivery source. The system includes a marker fixable in or on the body at a selected position relative to the target, such as in or near the target. The marker is excitable by an external excitation source to produce an identifiable signal while affixed in or on the body. A sensor array with a plurality of sensors is provided external of the body, and the sensors are spaced apart in a known geometry relative to each other.

Problems solved by technology

However, with the increased dose of delivered radiation comes the potential for increased complications to healthy tissues, unless measures are taken to reduce the amount of adjacent normal tissue irradiated.

Some margin has been necessary, however due to day-by-day variability in the initial radiation treatment setup and delivery with existing systems.

In addition, if the patient is set up so the radiation beam is initially off target, or if the target moves during treatment, the beam hits more of the normal tissue and causes increased collateral damage to the normal tissue, as well as potentially under-dosing the target.

Thus, day-by-day, minute-by-minute changes in radiation treatment setup and target motion have posed serious challenges when dose escalation is attempted with current patient setup processes.

Accordingly, the doctors and technicians cannot tell how far the target has actually moved relative to the machine's isocenter.

Such internal motion of the target can cause inaccuracies in treatment deliveries, so larger margins of healthy tissue are prescribed and irradiated to compensate for likely internal target motions.

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