# US 7,408,162 B2 · Method for reducing nuclear medicine scanning time

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- Number: US 7,408,162 B2
- Document ID: US7408162B2
- Status: Granted
- Kind: B2
- Application number: 11/239,271
- Filed: 2005-09-29
- Published: 2007-03-29
- Granted: 2008-08-05
- Earliest claimed: 2005-09-29
- Assignees: Siemens Medical Solutions USA, Inc.
- Inventors: Sharon Xiaorong Wang
- Web page: https://patentgrep.com/patent/US7408162B2

## CPC

- G01T 1/1642: {using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras}
- A61B 6/037: {Emission tomography}
- G01T 1/1648: {Ancillary equipment for scintillation cameras, e.g. reference markers, devices for removing motion artifacts, calibration devices (adapted for flow studies G01T1/1647)}
- G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A method for reducing the scanning time of SPECT broadly includes determining a physical characteristic of an object within a radiation field, calculating an optimal starting angle of at least two detectors based on the physical characteristic of the object and a trajectory of the at least two detectors such that the geometric efficiency of the detectors along the trajectory can be maximized, angularly displacing the detectors based on the calculated optimal starting angle, scanning the object within the field to detect one or more gamma photons emanating from the object, and preparing an image from the one or more detected gamma photons. Preferably, the physical characteristic of the object is its location within the field, but can include properties such as signal to noise ratio, shape of the object, etc.

## Claims

### Claim 1

A method of acquiring images from a radiation field comprising:
determining a spatial location of an object within the field;
calculating an optimal scan starting angle, with respect to said object, of a configuration of at least two detectors angularly disposed with respect to each other at a preselected angle, based on the spatial location of the object such that the geometrical efficiency of the configuration of detectors along a trajectory can be maximized;
angularly displacing the configuration of detectors with respect to said object, based on the calculated optimal scan starting angle;
scanning the object within the field with said configuration of detectors starting at said optimal scan starting angle to detect one or more gamma photons emanating from the object; and,
preparing an image from the one or more detected gamma photons.

### Claim 2 (depends on 1)

The method of claim 1 wherein the configuration of detectors comprises a pair of detectors configured for performing SPECT.

### Claim 3 (depends on 2)

The method of claim 2 wherein the optimal scan starting angle of the pair of detectors can be described by:
D
⁡
(
φ
)
=
D
1
2
⁡
(
φ
)
+
D
2
⁢
2
⁡
(
φ
)
;
⁢
and
,
f
⁡
(
α
)
=
∫
α
α
+
θ°
⁢
D
⁡
(
φ
)
⁢
ⅆ
φ
wherein,
D corresponds to detector distance from the object;
θ corresponds to a period of the trajectory;
φ corresponds to detector angle during scanning; and,
α corresponds to detector starting angle; and,
f(α) achieves a minimum value.

### Claim 4 (depends on 3)

The method of claim 3 wherein θ is 90°.

### Claim 5 (depends on 4)

The method of claim 4 wherein the pair of detectors is disposed at a 90° angle with respect to each other.

### Claim 6 (depends on 3)

The method of claim 3 wherein θ is 180°.

### Claim 7 (depends on 6)

The method of claim 6 wherein the pair of detectors is disposed at a 180° angle with respect to each other.

### Claim 8 (depends on 3)

The method of claim 3 wherein the pair of detectors is disposed at a 76° angle with respect to each other.

### Claim 9 (depends on 3)

The method of claim 3 wherein the trajectory comprises an arcuate portion.

### Claim 10 (depends on 3)

The method of claim 3 wherein the trajectory comprises a line portion.

### Claim 11

A method of acquiring images from a radiation field comprising:
determining a physical characteristic of an object within the field;
calculating an optimal scan starting angle, with respect to said object, of a configuration of at least two detectors angularly disposed with respect to each other at a preselected angle, based on the physical characteristic of the object and a trajectory of the configuration of at least two detectors such that the geometric efficiency of the configuration of detectors along the trajectory can be maximized;
angularly displacing the configuration of detectors with respect to said object, based on the calculated optimal scan_starting angle;
scanning the object with said configuration of detectors starting at said optimal scan starting angle within the field to detect one or more gamma photons emanating from the object; and,
preparing an image from the one or more detected gamma photons.

### Claim 12 (depends on 11)

The method of claim 11 wherein the physical characteristic is spatial location of the object within the field.

### Claim 13 (depends on 12)

The method of claim 12 wherein the configuration of detectors comprises a pair of detectors configured for performing SPECT.

### Claim 14 (depends on 13)

The method of claim 13 wherein the optimal scan starting angle of the pair of detectors can be described by:
D
⁡
(
φ
)
=
D
1
2
⁡
(
φ
)
+
D
2
⁢
2
⁡
(
φ
)
;
⁢
and
,
f
⁡
(
α
)
=
∫
α
α
+
θ°
⁢
D
⁡
(
φ
)
⁢
ⅆ
φ
wherein,
B corresponds to detector distance from the object;
θ corresponds to period of the trajectory;
φ corresponds to detector angle during scanning; and,
α corresponds to detector starting angle; and,
f(α) achieves a minimum value.

### Claim 15 (depends on 14)

The method of claim 14 wherein θ is 90°.

### Claim 16 (depends on 15)

The method of claim 15 wherein the pair of detectors are disposed at a 90° angle with respect to one another.

### Claim 17 (depends on 14)

The method of claim 14 wherein θ is 180°.

### Claim 18 (depends on 17)

The method of claim 17 wherein the pair of detectors are disposed at a 180° angle with respect to one another.

### Claim 19 (depends on 14)

The method of claim 14 wherein the pair of detectors are disposed at a 76° angle with respect to one another.

### Claim 20 (depends on 14)

The method of claim 14 wherein the trajectory comprises an arcuate portion.

### Claim 21 (depends on 14)

The method of claim 14 wherein the trajectory comprises a line portion.

### Claim 22 (depends on 11)

The method of claim 11 wherein the physical characteristic is signal to noise ratio.

### Claim 23

A method of acquiring images with a SPECT scanning system comprising:
determining a spatial location of an object to be scanned;
calculating an optimal rotational scan starting angle of a configuration of at least two detectors angularly disposed with respect to each other at a preselected angle, based on the spatial location of the object and the trajectory of the configuration of at least two detectors such that the geometrical efficiency of the detectors can be maximized along the trajectory;
rotationally displacing the configuration of detectors based on the calculated optimal rotational scan starting angle;
scanning the object with said configuration of detectors starting at said optimal rotational scan starting angle within the field to detect one or more gamma photons emanating from the object; and, preparing an image from the one or more detected gamma photons.