US2009213985A1PendingUtilityA1
System and method for tomographic reconstruction utilizing circular trajectory and scanogram to reduce artifacts
Est. expiryOct 31, 2027(~1.3 yrs left)· nominal 20-yr term from priority
A61B 6/032A61B 6/027
53
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
A computed tomography apparatus and method using line data estimated from circle data and scanogram data. An image of a subject is reconstructed using the circle data and the estimated line data. The circle data and scanogram data may be weighted in estimating the line data. The apparatus and method are useful in diminishing or eliminating streak artifacts in reconstructed images such as images including the spine.
Claims
exact text as granted — not AI-modified1 . A computed-tomography apparatus, comprising:
an x-ray source; an x-ray detector disposed to receive x-rays from said x-ray source; a unit to collect circle data and scanogram data; a processing unit for estimating line data from said circle data and said scanogram data and for performing reconstruction of an image using said circle data and said estimated line data.
2 . An apparatus as recited in claim 1 , wherein said processing unit is configured to estimated said line data using:
P
L
(
u
,
v
,
h
)
=
v
v
+
h
P
C
(
u
,
v
+
h
,
λ
0
)
+
h
v
+
h
P
S
(
u
,
v
+
h
)
where P C (u, v, λ) is said circle data and P S (u, z) is said scanogram data.
3 . An apparatus as recited in claim 1 , wherein said processing unit is configured to estimated said line data using:
P
L
(
u
,
v
,
h
)
=
{
w
1
P
C
(
u
,
v
+
h
,
λ
0
)
+
if
v
>
0
(
1
-
w
1
)
P
S
(
u
,
v
+
h
)
,
w
2
P
C
(
-
u
,
v
′
+
h
,
λ
0
+
π
-
2
γ
)
+
if
v
<
0
(
1
-
w
2
)
P
S
(
u
,
v
+
h
)
,
w
1
=
v
v
+
h
w
2
=
-
2
v
cos
u
h
,
v
′
=
v
cos
2
u
for
a
cylindrical
detector
w
2
=
-
2
v
h
SDD
2
SDD
2
+
u
2
,
v
′
=
v
SDD
2
+
u
2
SDD
2
for
a
flat
detector
where P C (u, v, λ) is said circle data, P S (u, z) is said scanogram data, and w 1 and w 2 are weighting factors.
4 . An apparatus as recited in claim 2 , wherein said processing unit is further configured to estimate said line data using
P
LF
(
u
,
v
,
h
)
=
1
2
(
1
+
cos
h
π
d
)
×
P
L
(
u
,
v
,
h
)
5 . An apparatus as recited in claim 3 , wherein said processing unit is further configured to estimate said line data using
P
LF
(
u
,
v
,
h
)
=
1
2
(
1
+
cos
h
π
d
)
×
P
L
(
u
,
v
,
h
)
6 . An apparatus as recited in claim 3 , wherein said weighting factors comprise:
w 1S =3 w 1 2 −2 w 1 3 . w 2S =3 w 2 2 −2 w 2 3 .
7 . An apparatus as recited in claim 1 , wherein said processing unit is configured to estimate said line data using multiple scanogram rays for each estimated line ray.
8 . An apparatus as recited in claim 1 , wherein said processing unit is configured to estimate said line data using one of local smoothing and adaptive filtering.
9 . An apparatus as recited in claim 1 , wherein said processing unit is configured to reconstruct said image using one of filtered backprojection type reconstruction and backprojection filtration type reconstruction.
10 . An apparatus as recited in claim 1 , wherein said processing unit is configured to reconstruct said image using full revolution circular data.
11 . An apparatus as recited in claim 1 , wherein said processing unit is configured to reconstruct said image using partial revolution circular data.
12 . A computed tomography method, comprising:
exposing a subject to x-rays; collecting circle data; collecting scanogram data; estimating line data using said circle data and said scanogram data; and reconstructing an image of said subject using said estimated line data and said circle data.
13 . A method as recited in claim 12 , comprising estimating said line data using:
P
L
(
u
,
v
,
h
)
=
v
v
+
h
P
C
(
u
,
v
+
h
,
λ
0
)
+
h
v
+
h
P
S
(
u
,
v
+
h
)
where P C (u, v, λ) is said circle data and P S (u, z) is said scanogram data.
14 . A method as recited in claim 12 , comprising estimating said line data using:
P
L
(
u
,
v
,
h
)
=
{
w
1
P
C
(
u
,
v
+
h
,
λ
0
)
+
if
v
>
0
(
1
-
w
1
)
P
S
(
u
,
v
+
h
)
,
w
2
P
C
(
-
u
,
v
′
+
h
,
λ
0
+
π
-
2
γ
)
+
if
v
<
0
(
1
-
w
2
)
P
S
(
u
,
v
+
h
)
,
w
1
=
v
v
+
h
w
2
=
-
2
v
cos
u
h
,
v
′
=
v
cos
2
u
for
a
cylindrical
detector
w
2
=
-
2
v
h
SDD
2
SDD
2
+
u
2
,
v
′
=
v
SDD
2
+
u
2
SDD
2
for
a
flat
detector
where P C (u, v, λ) is said circle data, P S (u, z) is said scanogram data, w 1 and w 2 are weighting factors.
15 . A method as recited in claim 12 , comprising estimating said line data using
P
LF
(
u
,
v
,
h
)
=
1
2
(
1
+
cos
h
π
d
)
×
P
L
(
u
,
v
,
h
)
16 . A method as recited in claim 14 , comprising estimating said line data using
P
LF
(
u
,
v
,
h
)
=
1
2
(
1
+
cos
h
π
d
)
×
P
L
(
u
,
v
,
h
)
17 . An method as recited in claim 14 , wherein said weighting factors comprise
w 1S =3 w 1 2 −2 w 1 3 . w 2S =3 w 2 2 −2 w 2 3 .
18 . A method as recited in claim 12 , comprising estimating said line data using multiple scanogram rays for each estimated line ray.
19 . A method as recited in claim 12 , comprising estimating said line data using one of local smoothing and adaptive filtering.
20 . A method as recited in claim 12 , wherein said reconstructing comprises one of filtered backprojection type reconstruction and backprojection filtration type reconstruction.
21 . A method as recited in claim 12 , wherein said reconstructing comprises reconstruction of full revolution circular data.
22 . A method as recited in claim 12 , wherein said reconstructing comprises reconstruction of partial revolution circular data.
23 . A computer readable-medium containing instructions that may be executed by a computer to perform a method, comprising:
collecting circle data from an x-ray scan of a subject; collecting scanogram data from said x-ray scan; estimating line data using said circle data and said scanogram data; and reconstructing an image of said subject using said estimated line data and said circle data.
24 . A medium as recited in claim 23 , wherein method comprises:
estimating said line data using:
P
L
(
u
,
v
,
h
)
=
v
v
+
h
P
C
(
u
,
v
+
h
,
λ
0
)
+
h
v
+
h
P
S
(
u
,
v
+
h
)
where P C (u, v, λ) is said circle data and P S (u, z) is said scanogram data.
25 . A medium as recited in claim 23 , wherein said method comprises:
estimating said line data using:
P
L
(
u
,
v
,
h
)
=
{
w
1
P
C
(
u
,
v
+
h
,
λ
0
)
+
if
v
>
0
(
1
-
w
1
)
P
S
(
u
,
v
+
h
)
,
w
2
P
C
(
-
u
,
v
′
+
h
,
λ
0
+
π
-
2
γ
)
+
if
v
<
0
(
1
-
w
2
)
P
S
(
u
,
v
+
h
)
,
w
1
=
v
v
+
h
w
2
=
-
2
v
cos
u
h
,
v
′
=
v
cos
2
u
for
a
cylindrical
x
-
ray
detector
w
2
=
-
2
v
h
SDD
2
SDD
2
+
u
2
,
v
′
=
v
SDD
2
+
u
2
SDD
2
for
a
flat
x
-
ray
detector
where P C (u, v, λ) is said circle data, P S (u, z) is said scanogram data, w 1 and w 2 are weighting factors.
26 . A medium as recited in claim 25 , wherein said method comprises:
estimating said line data using
P
LF
(
u
,
v
,
h
)
=
1
2
(
1
+
cos
h
π
d
)
×
P
L
(
u
,
v
,
h
)
27 . A medium as recited in claim 24 , wherein said method comprises:
estimating said line data using
P
LF
(
u
,
v
,
h
)
=
1
2
(
1
+
cos
h
π
d
)
×
P
L
(
u
,
v
,
h
)
28 . A medium as recited in claim 25 , wherein said weighting factors comprise
w 1S =3 w 1 2 −2 w 1 3 . w 2S =3 w 2 2 −2 w 2 3 .
29 . A medium as recited in claim 23 , wherein said method comprises estimating said line data using multiple scanogram rays for each estimated line ray.
30 . A medium as recited in claim 23 , wherein said method comprises estimating said line data using one of local smoothing and adaptive filtering.
31 . A medium as recited in claim 23 , wherein said reconstructing comprises one of filtered backprojection type reconstruction and backprojection filtration type reconstruction.
32 . A medium as recited in claim 23 , wherein said reconstructing comprises reconstruction of full revolution circular data.
33 . A medium as recited in claim 23 , wherein said reconstructing comprises reconstruction of partial revolution circular data.Join the waitlist — get patent alerts
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