Systems And Methods For Isotopic Source External Beam Radiotherapy

A method comprising:

• providing one or more initial treatment parameters selected from a group consisting of a number of isotopic beams, isocenters for each isotopic beam, a prescribed dose for a target, a maximum dose for a critical structure, and one or more dose volume histogram constraints;
• determining an initial fluence map including one or more beamlets, the initial fluence map specifying a fluence value for each of the one or more beamlets;
• determining a first delivery sequence for the fluence values in the initial fluence map, the first delivery sequence including one or more apertures formed by a first set of one or more leaves and a second set of one or more leaves in a collimator;
• calculating one or more dose values based on the one or more apertures in the first delivery sequence using an a priori dose calculation method;
• comparing the one or more calculated dose values with the prescribed dose;
• and
• determining a second delivery sequence if there is a significant error between the one or more calculated dose values and the prescribed dose.

A method comprising:

• providing one or more initial treatment parameters selected from a group consisting of a number of isotopic beams, isocenters for each isotopic beam, a prescribed dose for a target, a maximum dose for a critical structure, and one or more dose volume histogram constraints;
• discretizing each of the isotopic beams into one or more beamlets;
• computing a cost for each of the one or more beamlets;
• for each of the one or more beamlets, keeping the beamlet if the cost is greater than a threshold cost and discarding the beamlet if the cost is equal to or less than the threshold cost;
• determining a delivery sequence for the one or more kept beamlets, the delivery sequence including one or more apertures formed by a first set of one or more leaves and a second set of one or more leaves in a collimator;
• calculating a dose value for each of the one or more apertures using an a priori dose calculation method;
• determining a beam-on-time value for each of the one or more apertures;
• calculating a first value of an objective function based on the determined beam-on-time values;
• for each of the one or more apertures, discarding the aperture if the determined beam-on-time value is less than a beam-on-time threshold;
• adjusting the beam-on-time value for the one or more apertures that are not discarded;
• calculating a second value of the objective function based on the adjusted beam-on-time values;
• and
• determining whether the objective function has converged based on a difference between the first value of the objective function and the second value of the objective function.

A system comprising:

• a processor;
• and
• a memory, wherein the processor and the memory are configured to perform operations comprising:
• providing one or more initial treatment parameters selected from group consisting of a number of isotopic beams, isocenters for each isotopic beam, a prescribed dose for a target, a maximum dose for a critical structure, and one or more dose volume histogram constraints;
• determining an initial fluence map including one or more beamlets, the initial fluence map specifying a fluence value for each of the one or more beamlets;
• and
• determining a delivery sequence for the fluence values in the initial fluence map, the delivery sequence including one or more apertures formed by a first set of one or more leaves and a second set of one or more leaves in a collimator, the one or more apertures having a specified size constrained to substantially less than a maximum size associated with the collimator, when the isotopic beam is near the critical structure.

A system comprising:

• a processor;
• and
• a memory, wherein the processor and the memory are configured to perform operations comprising:
• providing one or more initial treatment parameters selected from a group consisting of a number of isotopic beams, isocenters for each isotopic beam, a prescribed dose for a target, a maximum dose for a critical structure, and one or more dose volume histogram constraints;
• determining an initial fluence map including one or more beamlets, the initial fluence map specifying a fluence value for each of the one or more beamlets;
• determining a first delivery sequence for the fluence values in the initial fluence map, the first delivery sequence including one or more apertures formed by a first set of one or more leaves and a second set of one or more leaves in a collimator;
• calculating one or more dose values based on the one or more apertures in the first delivery sequence using an a priori dose calculation method;
• comparing the one or more calculated dose values with the prescribed dose;
• and
• determining a second delivery sequence if there is a significant error between the one or more calculated dose values and the prescribed dose.

A system comprising:

• a processor;
• and
• a memory, wherein the processor and the memory are configured to perform operations comprising:
• providing one or more initial treatment parameters selected from a group consisting of a number of isotopic beams, isocenters for each isotopic beam, a prescribed dose for a target, a maximum dose for a critical structure, and one or more dose volume histogram constraints;
• discretizing each of the isotopic beams into one or more beamlets;
• computing a cost for each of the one or more beamlets;
• for each of the one or more beamlets, keeping the beamlet if the cost is greater than a threshold cost and discarding the beamlet if the cost is equal to or less than the threshold cost;
• determining a delivery sequence for the one or more kept beamlets, the delivery sequence including one or more apertures formed by a first set of one or more leaves and a second set of one or more leaves in a collimator;
• calculating a dose value for each of the one or more apertures using an a priori dose calculation method;
• determining a beam-on-time value for each of the one or more apertures;
• calculating a first value of an objective function based on the determined beam-on-time values;
• for each of the one or more apertures, discarding the aperture if the determined beam-on-time value is less than a beam-on-time threshold;
• adjusting the beam-on-time value for the one or more apertures that are not discarded;
• calculating a second value of the objective function based on the adjusted beam-on-time values;
• and
• determining whether the objective function has converged based on a difference between the first value of the objective function and the second value of the objective function.

A non-transitory computer-readable medium containing instructions to configure a processor to perform operations comprising:

• providing one or more initial treatment parameters selected from a group consisting of a number of isotopic beams, isocenters for each isotopic beam, a prescribed dose for a target, a maximum dose for a critical structure, and one or more dose volume histogram constraints;
• determining an initial fluence map including one or more beamlets, the initial fluence map specifying a fluence value for each of the one or more beamlets;
• and
• determining a delivery sequence for the fluence values in the initial fluence map, the delivery sequence including one or more apertures formed by a first set of one or more leaves and a second set of one or more leaves in a collimator, the one or more apertures having a specified size constrained to substantially less than a maximum size associated with the collimator, when the isotopic beam is near the critical structure.

A non-transitory computer-readable medium containing instructions to configure a processor to perform operations comprising:

• providing one or more initial treatment parameters selected from a group consisting of a number of isotopic beams, isocenters for each isotopic beam, a prescribed dose for a target, a maximum dose for a critical structure, and one or more dose volume histogram constraints;
• determining an initial fluence map including one or more beamlets, the initial fluence map specifying a fluence value for each of the one or more beamlets;
• determining a first delivery sequence for the fluence values in the initial fluence map, the first delivery sequence including one or more apertures formed by a first set of one or more leaves and a second set of one or more leaves in a collimator;
• calculating one or more dose values based on the one or more apertures in the first delivery sequence using an a priori dose calculation method;
• comparing the one or more calculated dose values with the prescribed dose;
• and
• determining a second delivery sequence if there is a significant error between the one or more calculated dose values and the prescribed dose.

A non-transitory computer-readable medium containing instructions to configure a processor to perform operations comprising:

• providing one or more initial treatment parameters selected from a group consisting of a number of isotopic beams, isocenters for each isotopic beam, a prescribed dose for a target, a maximum dose for a critical structure, and one or more dose volume histogram constraints;
• discretizing each of the isotopic beams into one or more beamlets;
• computing a cost for each of the one or more beamlets;
• for each of the one or more beamlets, keeping the beamlet if the cost is greater than a threshold cost and discarding the beamlet if the cost is equal to or less than the threshold cost;
• determining a delivery sequence for the one or more kept beamlets, the delivery sequence including one or more apertures formed by a first set of one or more leaves and a second set of one or more leaves in a collimator;
• calculating a dose value for each of the one or more apertures using an a priori dose calculation method;
• determining a beam-on-time value for each of the one or more apertures;
• calculating a first value of an objective function based on the determined beam-on-time values;
• for each of the one or more apertures, discarding the aperture if the determined beam-on-time value is less than a beam-on-time threshold;
• adjusting the beam-on-time value for the one or more apertures that are not discarded;
• calculating a second value of the objective function based on the adjusted beam-on-time values;
• and
• determining whether the objective function has converged based on a difference between the first value of the objective function and the second value of the objective function.