Blood on-line sampler data
Arterial whole blood radioactivity concentration can be measured with an on-line detector ("blood pump"). Currently, there are three systems installed in the Turku PET Centre, two made by Scanditronics/GEMS and one made by Allogg. All on-line detectors have different calibration coefficients, and there are some differences in processing of the data:
On-line samplers
Each on-line sampler is normally used only with a certain PET scanner, but they can be swapped if necessary.
It may be necessary to collect a few blood samples while the on-line sampler is still working. These may be needed for example for metabolite analysis or for determining the blood-to-plasma ratio. These manual samples can usually be taken from the end of the tubing, so that they do not cause any disturbance in the on-line data.
GE Advance
On-line detector that is normally located at GE Advance PET scanner, is manufactured by GEMS. Raw on-line detector data is stored in a specific format. After the necessary processing and correction steps, the data format is the same as in any other TAC files.
The raw blood data is written in the PETO system. From these directories the original data can be copied to group disks.
Studies conducted before 2000-02-03
Blood data files from GE Advance studies which date back to 2000-02-02 and
before that, do not contain the date of the study.
The date has to be added manually to the data file
in international format; without it, wrong calibration coefficients will be applied
(the first measured calibration coefficients).
For example, if the study date was Sep 24 1999, add the following line to the beginning
of the data file:
# 1999-09-24
HR+
Raw on-line detector data of Allogg ABSS (Allogg AB, Mariefred, Sweden, http://www.allogg.se/) is stored in a specific format. After the necessary processing and correction steps, the data format is the same as in any other TAC files.
The raw blood data is written in the PETO system. From these directories the original data can be copied to group disks. Data that was collected before PETO system was available can be found in S:\Lab\plasma\archive\hrplus_kevat2004_2005\ or S:\Lab\plasma\HRplus\.
HRRT
No on-line blood sampler is currently installed permanently to HRRT scanner room, but our in-house software for Allogg can be used from HRRT control workstation (PC/Windows) when necessary.
GE-PET
The raw blood data is written in the PETO system. From these directories the original data can be copied to group disks.
ECAT931 (put out of operation in the end of April 2005)
Scanditronics on-line detector was located at ECAT931 during the years it was in operation. On-line detector is working fine, and will be used in future in connection with some other scanner, but its location has not yet been decided.
Raw on-line detector data is stored in a specific format. After the necessary processing and correction steps, the data format is the same as in any other TAC files.
The raw blood data were written in directory /pet-storage/Lab/plasma/ecat/*_blo.lis (UNIX) or S:\Lab\plasma\ecat\ (Windows). From this directory the original data may have been moved to group disks and MO or CD-ROM disks.
Processing on-line blood sampler data in TPC
Usually, on-line detector data is processed by different software (scripts) for each tracer (oxygen-15 and carbon-11 and fluorine-18 tracers).
If you need to calibrate the data by yourself, use blo2kbq in Windows XP command prompt window or Sun/Solaris command tool with the following command-line options and arguments:
- with option -c the location and name of datafile containing the calibration coefficients,
- to correct the data for radioactive decay, specify the isotope code with option -d,
- option -i with isotope code (again) to select the correct calibration coefficient and branching ratio,
- optionally, the name of the output file may be specified with option -o,
- the name of the original on-line detector ("blood pump") data file.
As an example, a GE Advance study might be processed with this command on
a SUN terminal:
blo2kbq -c=/pet-storage/Lab/plasma/bsampler_calibration/pump_cal.dat -d=O -i=O -o=./uo0268blo.kbq /pet-storage/Lab/plasma/ge/patient/uo268.bld
or in Windows XP command prompt window:
blo2kbq -c=S:\Lab\plasma\bsampler_calibration\pump_cal.dat -d=O -i=O -o=uo0268blo.kbq uo268.bld
If you copy the calibration file (pump_cal.dat) to your own data directory, make sure that it contains an up-to-date calibration coefficient for all of your studies, because PET physicists can update only the original calibration file in \\pet-storage disk system.
Detailed information on how on-line detector raw data is processed is given with the raw data file format descriptions for Scanditronics/GEMS and Allogg ABSS.
