# US 2017/0281978 A1 · Dose-distribution estimation in proton therapy

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2017/0281978 A1
- Document ID: US20170281978A1
- Status: Published application
- Kind: A1
- Application number: 15/085,804
- Filed: 2016-03-30
- Published: 2017-10-05
- Earliest claimed: 2016-03-30
- Assignees: Varian Medical Systems International AG
- Applicants: Varian Medical Systems International AG.
- Inventors: Esa KUUSELA; Maria Isabel CORDERO MARCOS; Janne NORD
- Web page: https://patentgrep.com/patent/US20170281978A1

## CPC

- A61N 5/1071: {for verifying the dose delivered by the treatment plan}
- A61N 5/103: {Treatment planning systems}
- A61N 5/1031: {using a specific method of dose optimization}
- A61N 2005/1041: {using a library of previously administered radiation treatment applied to other patients}
- A61N 2005/1087: {Ions; Protons}
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)

## Abstract

A system for estimating a dose from a proton therapy plan includes a memory that stores machine instructions and a processor coupled to the memory that executes the machine instructions to subdivide a representation of a volume of interest in a patient anatomy traversed by a planned proton field into a plurality of voxels. The processor further executes the machine instructions to determine the distance from the source of the planned proton beam to one of the voxels. The processor also executes the machine instructions to compute the discrete contribution at the voxel to an estimated dose received by the volume of interest from the planned proton beam based on the distance between the source and the volume of interest.

## Claims

### Claim 1

A system for estimating a dose from a proton therapy plan, comprising:
a memory that stores machine instructions; and
a processor coupled to the memory that executes the machine instructions to subdivide a representation of a volume of interest into a plurality of voxels, determine a first distance associated with a planned proton field and a first voxel of the plurality of voxels, and compute a metric based on the first distance and a second distance associated with a target volume traversed by the planned proton field.

### Claim 2 (depends on 1)

The system of claim 1, wherein the volume of interest corresponds to the target volume and the metric represents a discrete contribution at the first voxel to an estimated dose received by the target volume.

### Claim 3 (depends on 1)

The system of claim 1, wherein a summation of a plurality of discrete contributions corresponding to the plurality of voxels yields an estimated dose corresponding to the volume of interest, the plurality of discrete contributions including the metric.

### Claim 4 (depends on 1)

The system of claim 1, wherein the second distance is further associated with a proximal point where the proton field enters the target volume, a third distance is associated with a distal point where the proton field exits the target volume, the first distance is greater than the second distance and less than the third distance, and the metric equals a prescription dose associated with the target volume.

### Claim 5 (depends on 1)

The system of claim 1, wherein the processor further executes the machine instructions to compute the metric based on a prescription dose associated with the target volume and a third distance traveled by the planned proton field through the target volume, the second distance is further associated with a proximal point where the proton field enters the target volume, and the first distance is less than the second distance.

### Claim 6 (depends on 5)

The system of claim 5, wherein the metric equals:
Δ
+
(
d
-
Δ
)

e
-
a

T
s
-
x
+
b
,
wherein x is the first distance, Ts is the second distance, Δ is the third distance, d is a prescription dose associated with the target volume, a is a first exponential parameter, and b is a second exponential parameter.

### Claim 7 (depends on 1)

The system of claim 1, wherein the second distance is further associated with a distal point where the proton field exits the target volume, the first distance is greater than the second distance, and the metric equals zero.

### Claim 8

A method of estimating a dose from a proton therapy plan, comprising:
subdividing a representation of a volume of interest into a plurality of voxels;
determining a first distance associated with a planned proton field and a first voxel of the plurality of voxels; and
computing a metric based on the first distance and a second distance associated with a target volume traversed by the planned proton field.

### Claim 9 (depends on 8)

The system of claim 8, wherein the volume of interest corresponds to the target volume and the metric represents a discrete contribution at the first voxel to an estimated dose received by the target volume.

### Claim 10 (depends on 8)

The method of claim 8, further comprising summing a plurality of discrete contributions corresponding to the plurality of voxels to yield an estimated dose corresponding to the volume of interest, the plurality of discrete contributions including the metric.

### Claim 11 (depends on 8)

The method of claim 8, wherein computing the metric further comprises computing the metric based on a plan parameter, the second distance is further associated with a proximal point where the proton field enters the target volume, a third distance is associated with a distal point where the proton field exits the target volume, and the first distance is greater than the second distance and less than the third distance.

### Claim 12 (depends on 11)

The method of claim 11, wherein the plan parameter comprises a prescription dose associated with the target volume.

### Claim 13 (depends on 11)

The method of claim 11, wherein the metric equals the plan parameter.

### Claim 14 (depends on 8)

The method of claim 8, wherein computing the metric further comprises computing the metric based on a plan parameter and a third distance traveled by the planned proton field through the target volume, the second distance is further associated with a proximal point where the proton field enters the target volume, and the first distance is less than the second distance.

### Claim 15 (depends on 14)

The method of claim 14, wherein the plan parameter comprises a prescription dose associated with the target volume.

### Claim 16 (depends on 14)

The method of claim 14, wherein computing the metric further comprises computing the metric based on at least one exponential parameter.

### Claim 17 (depends on 14)

The method of claim 14, wherein the metric equals:
Δ
+
(
d
-
Δ
)

e
-
a

T
s
-
x
+
b
,
wherein x is the first distance, Ts is the second distance, Δ is the third distance, d is a prescription dose associated with the target volume, a is a first exponential parameter, and b is a second exponential parameter.

### Claim 18 (depends on 14)

The system of claim 14, wherein the volume of interest corresponds to an organ at risk with respect to the proton therapy plan and the metric represents a discrete contribution at the first voxel to an estimated dose received by the organ at risk.

### Claim 19 (depends on 8)

The method of claim 8, wherein the second distance is further associated with a distal point where the proton field exits the target volume, the first distance is greater than the second distance, and the metric equals zero.

### Claim 20

A computer program product for estimating a dose from a proton therapy plan, comprising:
a non-transitory, computer-readable storage medium encoded with instructions adapted to be executed by a processor to implement:
subdividing a representation of a volume of interest into a plurality of voxels;
determining a first distance associated with a planned proton field and a first voxel of the plurality of voxels;
computing a metric based on the first distance and a second distance associated with a target volume traversed by the planned proton field, the metric representing a first discrete contribution at the first voxel to an estimated dose received by the volume of interest; and
summing a plurality of discrete contributions corresponding to the plurality of voxels to yield an estimated dose corresponding to the volume of interest, the plurality of discrete contributions including the first discrete contribution.