Systems and methods for use in emission guided radiation therapy

Abstract

Described herein are systems and methods for positioning a radiation source with respect to one or more regions of interest in a coordinate system. Such systems and methods may be used in emission guided radiation therapy (EGRT) for the localized delivery of radiation to one or more patient tumor regions. These systems comprise a gantry movable about a patient area, where a plurality of positron emission detectors, a radiation source are arranged movably on the gantry, and a controller. The controller is configured to identify a coincident positron annihilation emission path and to position the radiation source to apply a radiation beam along the identified emission path. The systems and methods described herein can be used alone or in conjunction with surgery, chemotherapy, and/or brachytherapy for the treatment of tumors.

1 - 29 . (canceled) 
     
     
         30 . A method for radiotherapy comprising:
 injecting a non-FDG PET tracer into a patient;   acquiring PET emission data from a region of interest after tracer uptake;   determining a biological property of the region of interest using the acquired PET emission data; and   delivering therapeutic radiation to the region of interest based at least in part on the biological property of the region of interest.   
     
     
         31 . The method of  claim 30 , wherein the biological property comprises one or more of hypoxia levels, cellular proliferation levels, and cell apoptosis levels. 
     
     
         32 . The method of  claim 30 , wherein delivering therapeutic radiation to the region interest comprises delivering radiation that is proportional to an intensity of the PET emission data. 
     
     
         33 . The method of  claim 30 , wherein the non-FDG PET tracer is a first PET tracer, and the method further comprises injecting a second PET tracer into the patient. 
     
     
         34 . The method of  claim 33 , wherein the first PET tracer and the second PET tracer are injected simultaneously into the patient. 
     
     
         35 . The method of  claim 34 , further comprising combining the first PET tracer and the second PET tracer into a cocktail, and wherein injecting the first PET tracer and the second PET tracer comprises injecting the cocktail into the patient. 
     
     
         36 . The method of  claim 34 , wherein the second PET tracer is injected after the first PET tracer is injected. 
     
     
         37 . The method of  claim 34 , wherein the first PET tracer and the second PET tracer are each selected from the group consisting of a F-MISO tracer, a FLT tracer, a ACBC tracer, an ASTM tracer, and an ML-10 tracer. 
     
     
         38 . The method of  claim 30 , wherein the PET tracer is selected from the group consisting of a F-MISO tracer, a FLT tracer, a ACBC tracer, an ASTM tracer, and an ML-10 tracer. 
     
     
         39 . The method of  claim 30 , further comprising determining a PET tracer distribution based on the acquired PET emission data in the region of interest, and delivering therapeutic radiation based at least in part on the PET tracer distribution. 
     
     
         40 . The method of  claim 38 , wherein determining the PET tracer distribution comprises identifying a sub-region of increased PET tracer uptake within the region of interest. 
     
     
         41 . The method of  claim 39 , wherein the sub-regions correspond to areas of hypoxia or increased cellular proliferation or both. 
     
     
         42 . The method of  claim 39 , wherein delivering therapeutic radiation comprises delivering an increased amount of radiation to the identified sub-region. 
     
     
         43 . The method of  claim 39 , further comprising tracking motion of the identified sub-region. 
     
     
         44 . The method of  claim 38 , wherein determining the PET tracer distribution comprises identifying a sub-region of decreased PET tracer uptake within the region of interest. 
     
     
         45 . The method of  claim 43 , wherein identifying the sub-region of decreased PET tracer uptake comprises determining a number of line-of-response (LOR) emissions in the acquired PET emission data, comparing the number of LOR emissions with a pre-determined threshold, and defining the sub-region as a portion of the region of interest having a number of LOR emissions that is less than the pre-determined threshold. 
     
     
         46 . The method of  claim 43 , wherein delivering therapeutic radiation comprises delivering an increased amount of radiation to the identified sub-region. 
     
     
         47 . The method of  claim 30 , further comprising implanting a marker in the region of interest and tracking the region of interest. 
     
     
         48 . The method of  claim 46 , wherein the marker comprises a fiducial marker or a radiopaque marker. 
     
     
         49 . The method of  claim 30 , wherein the acquired PET emission data comprises a plurality of line-of-response (LOR) emissions, and wherein delivering radiation comprises emitting radiation using the therapeutic radiation source along a LOR emission. 
     
     
         50 . A method for radiotherapy comprising:
 injecting a SPECT tracer into a patient;   acquiring SPECT emission data from a region of interest after tracer uptake;   determining a biological property of the region of interest using the acquired SPECT emission data; and   delivering therapeutic radiation to the region of interest based at least in part on the biological property of the region of interest.   
     
     
         51 . The method of  claim 50 , wherein the biological property comprises one or more of hypoxia levels, cellular proliferation levels, and cell apoptosis levels. 
     
     
         52 . The method of  claim 50 , wherein the SPECT tracer is a first tracer and the method further comprises injecting a second tracer into the patient. 
     
     
         53 . The method of  claim 52 , wherein the second tracer is a PET tracer. 
     
     
         54 . The method of  claim 52 , wherein the second tracer is a PET tracer. 
     
     
         55 . The method of  claim 52 , wherein the first SPECT tracer and the second tracer are injected simultaneously into the patient. 
     
     
         56 . The method of  claim 55 , further comprising combining the first SPECT tracer and the second tracer into a cocktail, and wherein injecting the first SPECT tracer and the second tracer comprises injecting the cocktail into the patient. 
     
     
         57 . The method of  claim 52 , wherein the second tracer is injected after the first SPECT tracer is injected. 
     
     
         58 . The method of  claim 52 , wherein the first SPECT tracer and the second tracer are each selected from the group consisting of a 99mTc-HL91 tracer and a 111In-Capromab pendetide tracer. 
     
     
         59 . The method of  claim 50 , wherein the SPECT tracer is selected from the group consisting of a 99mTc-HL91 tracer and a 111In-Capromab pendetide tracer. 
     
     
         60 . The method of  claim 50 , further comprising determining energy levels of the acquired SPECT emission data and wherein delivering therapeutic radiation comprises modulating radiation according to the energy levels of the SPECT emission data. 
     
     
         61 . The method of  claim 60 , wherein delivering therapeutic radiation to the region interest comprises delivering radiation that is proportional the energy levels of the SPECT emission data. 
     
     
         62 . The method of  claim 50 , further comprising determining a SPECT tracer distribution based on the acquired SPECT emission data in the region of interest, and delivering therapeutic radiation based at least in part on the SPECT tracer distribution. 
     
     
         63 . The method of  claim 62 , wherein determining the SPECT tracer distribution comprises identifying a sub-region of increased SPECT tracer uptake within the region of interest. 
     
     
         64 . The method of  claim 63 , wherein the sub-regions correspond to areas of hypoxia or increased cellular proliferation. 
     
     
         65 . The method of  claim 50 , wherein the acquired SPECT emission data comprises a plurality of single-photon linear paths, and wherein delivering therapeutic radiation comprises delivering radiation along a single-photon linear path.