Transcript Ei dian otsikkoa

The Impact of two new (PET) scanners on data management
Mika Teräs,
2nd Modelling Workshop in TPC, 2003-06-05
• At present we have 2 PET scanners
– Siemens CTI 931
– GE Advance
from year1988
from year 1996
• In Year 2003 3 new scanners
– Siemens CTI HR+ (Owned by Imanet Turku)
– CPS (CTI PET Systems) HRRT
– MRI scanner 50% for research
• In Year 2004 possibly 1 new scanner
– Replacing the oldest CTI 931 ?
– Combined CT/PET scanner
PET Tomographs
PET
Det. Rings Cryst/
Ring
Mat. = n
(--> 2n-1
slices)
Crystal
Dim.
Cryst/
Block
mm
Slice
thick
ness
Axial
FOV
cm
mm
GE
BGO
Advance
18
672
4.0x8.1x30
6x6
4.25
15.2
ECAT
931
BGO
8
512
5.6x13x30
4x8
6.75
10.8
HRRT
LSO/
LYSO
104
104
576
576
1.9x1.9x10
1.9x1.9x10
8x8
8x8
1.2
24.0
ECAT
HR +
BGO
32
576
4.0x4.4x30
8x8
2.5
15.5
PET Tomographs 2
PET
Trans Sensiaxial
tivity
res. cps/Bq/ml
NEC
kcps
Sinogram
dimension
Raw
data
size
mm
Mb
GE
Advance
5
31
160
281x256
50
ECAT
931
7
5
50
192x336
1.6
HRRT
3
35
220
256x288 x2
Aprox.
500
ECAT HR
+
5
31
110
288x144
20
Issues to be handled 1
• new data formats
– HRRT:
Interfile, Flat Format
– HR+:
ECAT 7.n
– MRI: not yet known (DICOM)
• raw data archiving
– local DAT drives as now or some centralised system
• reconstruction requirements
– standard reconstruction
– iterative reconstruction
– research for new methods
HRRT data organization and size
HRRT “Ring 1-Ring 2” coincidence map
All data are stored in flat format
+ Interfile header.
Standard acquisition mode is (span 9,
rd 67). It corresponds to 2209
sinograms in 15 segments.
Max. co-polar angle is ≈ 19°
Scan size (256x288x2209x2) is 325
MB.
Norm/Atten size are both 650 MB.
Image (256x256x207x4) size is 54
MB/frame.
At high resolution (span 3, rd 67), we
have 6367 sinograms in 43 segments:
data size is increased by 2.9 compared
to std mode !!!
z
span
segment -7
q
Every dot in the map is a
sinogram (256 x 288)
=> (104)2 sinograms
HRRT Interfile header: example for a scan file
!originating system := HRRT
!name of data file := g:\sinogram\lenox-mark-273352002.l32
!study date (dd:mm:yryr) := 14:03:2002
!study time (hh:mm:ss GMT) := 15:57:12
!PET data type := emission
data format := sinogram
number format := short
number of byte per pixel := 4
axial compression := 9
maximum ring difference := 67
energy window lower level[1] := 350
energy window upper level[1] := 650
image duration := 600
Patient name := lenoxCTI, mark
Patient DOB := 12:00:00 AM
Patient ID := 11111
Patient sex := Male
Dose type := FDG
Dosage Strength := 2.1 Mega-Bq
Normalization file name and path :=
G:\norm\default.n
Blank file name and path := g:\blank\default.s
matrix size [1] := 256
matrix size [2] := 288
matrix size [3] := 2209
number of bytes per pixel := 2
image relative start time := 720
frame := 1
Total Prompts := 765518378
Total Randoms := 295242655
Total Net Trues := 470275723
block singles 0 := 13456
block singles 1 := 14296
block singles 2 := 15965
block singles 3 := 14428
block singles 4 := 16499
block singles 5 := 16442
block singles 6 := 17529
block singles 7 := 13435
block singles 8 := 10770
....
Singles
block singles 934 := 18109
block singles 935 := 17051
average singles per block := 22714
Dead time correction factor := 1.191135
Issues to be handled 2
• image data flow
– new analysis workstations for clinical data
– new MRI data arrangement
• new security aspects
– Imanet Turku Studies
• compatibility with modelling programs
– new image format (ECAT7 ?)
– HR+ compatible with the Imanet London scanner
• acquiring of all related data
– motion correction with Polaris on List Mode data
– blood and activity measurements with new systems
» continuous blood sampling
» metabolite analysis
ECAT EXACT HR+: Premium Performance
• Highest overall
performance scanner
available for PET
• Finest sampling (2.4
mm)
• Highest resolution
• High image quality
ECAT to e.soft
Biograph console
Sun Acquisition Console
e.soft Database Browser
e.soft PET Display
• DICOM connectivity
• Configure display
• Zoom
• Autonormalize color scale
• Add slices
• Dual volume display
• View MIPs
• Draw ROIs (SUVs)
HRRT Hardware & software improvements
...
• New front end electronics and new
light tight interface: improves reliability
(less power inside head) and easier
access for service.
• The integration time was reduced to
120ns with subsequent improvements in
countrate performance
• Faster acquisition hardware was
introduced (2.0 Ghz Intel) which
achieves higher histogramming rates
(6.5 Mevents/s) with a larger memory
footprint (2.0 GB)
• A 100 MB/sec 1 TB RAID allows
storage of listmode data at high rate for
long periods of time.
HRRT Normalization
• Acquired in list mode with a rotating rod: long, uniform, weak.
• Measurement statistics: as long as possible (week-end)
• Fit data for rod radius and center of rotation, calculate dwell-time for
transforming ring into plane source. Invert data.
• Not component-based: 1 file per acq mode: (9,67) is 650 MB.
• Is used to detect missing data for reconstruction
2 D segment of 3D normalization
HRRT OSEM3D on the Windows/NT Heinzel Cluster
• A parallel version of OSEM3D code has been implemented
on a farm of 7 SGI quad-processors (28 Pentium III
Xeon@700 Mhz). It uses both shared and distributed
memory and Myrinet networking hardware with the GM
Message Passing System. [S. Vollmar et al, IEEE-MIC 2000
& MIC 2001 and 3D 01 conferences].
HRRT PET-MR fusion at high PET resolution ...
If we want to navigate into PET using inverse gray, the alternative
is to transform the MR CLUT into an edge detector and fuse these
contours with PET.
Intsalled at the end of 2001
DISCOVERY
Intsalled April 2002
REVEAL HD
Whole-body PET
CT
PET
PET Reconstruction
RHD
FORE + 2D-OSEM
DLS+
2D-OSEM