- 2013
I HC QUI
: 60 52 70
- 2013
1
2
3
5
1.1. T 5
1.2. C 6
1.3. T 7
NG 8
2.1. BORN ITERATIVE METHOD (BIM) 8
2.2. DISTORTED BORN ITERATIVE METHOD (DBIM) 11
2.3. B 12
2.4. MN BIMDBIM 14
2.4.1. 14
2.4.2. 18
2.4.3. 21
T 22
3.1. 22
3.2. TX. 24
28
4.1. M 28
4.2. V 42
45
O 46
1
BIM Born Iterative Method
DBIM Distorted Born Iterative Method
mm (pixel)
N /ngang
m/s
m/s
Pa )
Pa
Pa
rad/m
2
4 (N1 = 10) 24
4 (N1 = 11) 25
4 (N1 = 12) 26
(N = 20) 28
-(N1 = 10,N2 = 20) 28
(N = 22) 31
-(N1 = 11,N2 = 22) 32
(N = 34) 35
-(N1 = 17, N2 = 34) 35
(N = 40) 37
-(N1 = 20, N2 = 40) 38
40
41
4 42
6 43
3
8
14
14
5 15
15
(N=17) 16
1 17
4 17
5 18
19
1 19
4 20
5 20
21
th biu din m gia s ln l error (N1 = 10) 25
th biu din m gia s ln l error (N1 =11) 26
th biu din m gia s ln l error (N1 = 12) 27
(N = 20) 28
(N1 = 10, N = 20) 29
2 (N1 = 10, N = 20) 29
3 (N1 = 10, N = 20) 30
4 (N1 = 10, N = 20) 30
(N =20) 31
(N = 22) 31
1 (N1 = 11, N = 22) 32
2 (N1 = 11, N = 22) 32
3 (N1 = 11, N = 22) 33
4 (N1 = 11, N = 22) 33
(N = 22) 34
(N=34) 34
12 (N1 = 17, N = 34) 35
3 (N1 = 17, N = 34) 36
4 (N1 = 17, N = 34) 36
4
(N = 34) 37
(N = 40) 37
2 (N1 = 20, N = 40) 38
3 (N1 = 20, N = 40) 39
4 (N1 = 20, N = 40) 39
(N = 40) 40
4 41
6 41
42
43
4.30 44
4.31 44
5
1.1.
-
(magnetic resonance imaging),
Mm ln nht ch
tinh tp cng tu MRI (magnetic resonance imaging)
ra hu hing hnh CT cho chng rt t
vy, hii ta kt hp CT v to nh ch
tnh gii phu va khc ch
c di xi vi sc kho ca
b ng lth
ca mi ln cht.
a c i,
i c to b
n MRI tr th trong chnh thi k
t bng kim loi c
th chu ng ca t ng m
dng v thai u, tr khi tht cn thit.
nh hc b
mt phn c tin s t
th d
c ghi nhn theo thi gian th cho th nh c
chuyng c ph k c y
.
1910.
l-mode
-
ng
nht gia hai vt phn x u d
6
hin th i
dc tr).
. Tuy
-
.
-
-mode.
.
1.2.
.
.
-
[9-11].
7
5 MHz). Tr
.
.
)
lu ni suy kt hp vi xp x Born nhm
. xui nhong b
nu chp t lp t-23].
1.3.
2
(Distorted born iterative method)
.
8
2.1. Born Iterative Method (BIM)
2.1 .
Vic thc hic t
: Tt c u c nh trong su
Vt th s c xoay quanh trc nhnh. Nhng
mi xm b
b hing dc nh [12] .
: C nh vt th, ti mt v nh s ti
v i xc t ch cn mc hin Nr l
ng vi mt v
ng dch chuyn mng.
(2.1).
Rrif
Rrif
cc
r
0
11
2
0
2
1
2
(2.1)
9
,
f , ( ),R .
:
(2.2)
Vi
0
0
c
k
ng B
1
,
n s
rp
u
t tng ct t
r
c
t
sau:
'''' rdrrGrpr
rprprp
incsc
(2.3)
rp
sc
,
rp
inc
d ri r
bc biu
din dc N
2
pDCpp
inc
.
(2.4)
su c N
t
N
r
pDBp
sc
(2.5)
B
n
ng vi h s G
0
C
ma trn
ng vi h s G
0
I
:
(2.6)
.
.
.
10
(2.7)
ng [16
.
(2.5)
p
t.
gii quyt ta phng xp x Born lou kic khi bt
p:
inc
pp
0
k
inc
rrkJrp
00
(2.8)
Vi J
0
c 0,
k
rr
m
th k i.
u
sc
p
trong thc t c by hiu s cu ti
sc
p
li
d
s d p hai
1 The Born iterative method
1: Thit lp
0
inc
pp
0
n
B
C
3: Ln khi RRE <
{
p
s dng
n
RE ng vi
n
s dng (2.9)
6: Cp nh
1
n
bi (2.5).
7: n=n+1;
}
ng sai s RRE
11
đo
sc
đo
sc
n
p
ppDB
RRE
(2.9)
2.2. Distorted Born Iterative Method (DBIM)
.
(2.2).
:
(2.10)
(2.11)
rp
sc
,
rp
inc
(2.12)
.
:
(2.13)
:
(2.14)
:
(2.15)
:
(2.16)
.
:
12
(2.17)
(
;
2: The distorted Born iterative method
2: while(
) or( RRE <
), do
{
3: T,
,
,
(2.14)
4: T
5: T
(2.18)
6:
(2.16)
7: ; }
(2.18) [13].
2.3.
conjugate gradi13][14].
(2.17)
3: NCG method
0
.
.
4: for , do
5:
6:
7:
8:
13
9:
10:
11:
12: if
, then
13: Break iterations
14: end if
15: end for
(2.19) [13]:
(2.19)
[15].
4: The power iteration method with Rayleigh quotient
2: for , do
3:
4:
5: if
then
6: Break iterations
7: end if
8:
9:
10:
11: end for
14
2.4. DBIM
2.4.1.
1:
1MHz
1mm
9
121
2%
2.2.(2.1)
5)
15
5
:
(2.19)
(i,j)
16
2:
1MHz
1mm
9
121
2%
(N=17)
55)
17
2.7: 1
4
18
5
2.4.2.
3:
1MHz
1mm
40
20
2%
(2.1) 2.10
19
2.10
2.11,2.13
14c 5,5)
2.111
20
2.124
2.135
2.14
(2.19)2K
3
21
2.14
2.4.3.
p [17]
.
22
3.1.
:
DBIM -
Niter
- Step 0x
.
- Step 1:
(x
0).
.
- Step 2:
c
(
).
- Step 3: DBIM
) (Niter x) .
(Nearest
bilinear, bicubic, spline
t [18].
V:
5: Modified BIM
1: Thit lp
n
B
C
3: Ln khi (
or
{
s dng
ng vi
s dng (2.9)
6: Cp nh
bi (2.5).
7: n=n+1;