Construction and testing of a Positron Emission Tomography demonstrator
Zedda, Tiziana (2013)
Zedda, Tiziana
2013
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2013-06-05
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201306141231
https://urn.fi/URN:NBN:fi:tty-201306141231
Tiivistelmä
In this thesis we present the Avantomography demonstrator, which is being implemented and tested at Tampere University of Technology (Tampere, Finland). We also describe the first tests performed with it and the obtained results. The final aim of this master thesis is the energy calibration of the scintillating crystals and the electronic chain for data acquisition.
This new small Positron Emission Tomography (PET) demonstrator follows the recent innovations presented by the AX-PET group , at CERN. This is the first functioning version of a prototype of a light and compact PET scanner. The novel geometry, used to build the Avantomography demonstrator, is based on scintillating crystals and wavelength shifting (WLS) plastic strips, allowing high resolution and high sensitivity at the same time. The device consists in two small and compact modules, with two different adjustable parts inside. Each detector module is built up from long scintillator bars placed in the trans-axial plane and orthogonal WLS strip arrays. Preliminary tests with a standard positron emitter source has been performed in order to test the acquisition chain and to calibrate the demonstrator. First test has been performed measuring the intrinsic radioactivity of the scintillating crystals. For a complete calibration of one crystal, a test with a linear positron emitter source has been performed at the Tampere University Hospital (Tampere, Finland). From these measurements the spectra of different energy peaks are acquired and plotted. Using a dedicate MATLAB code, different Gaussian fits are calculated to find the position of each peak. With these values a 3-parameters fitting curve has been evaluated in order to obtain the non linear curve for the energy calibration. Furthermore a first evaluation of the energy resolution has been calculated starting from the acquired data. With its compact and light geometry, high resolution and high sensitivity this detector has a promising layout as a preclinical PET scanner.
This new small Positron Emission Tomography (PET) demonstrator follows the recent innovations presented by the AX-PET group , at CERN. This is the first functioning version of a prototype of a light and compact PET scanner. The novel geometry, used to build the Avantomography demonstrator, is based on scintillating crystals and wavelength shifting (WLS) plastic strips, allowing high resolution and high sensitivity at the same time. The device consists in two small and compact modules, with two different adjustable parts inside. Each detector module is built up from long scintillator bars placed in the trans-axial plane and orthogonal WLS strip arrays. Preliminary tests with a standard positron emitter source has been performed in order to test the acquisition chain and to calibrate the demonstrator. First test has been performed measuring the intrinsic radioactivity of the scintillating crystals. For a complete calibration of one crystal, a test with a linear positron emitter source has been performed at the Tampere University Hospital (Tampere, Finland). From these measurements the spectra of different energy peaks are acquired and plotted. Using a dedicate MATLAB code, different Gaussian fits are calculated to find the position of each peak. With these values a 3-parameters fitting curve has been evaluated in order to obtain the non linear curve for the energy calibration. Furthermore a first evaluation of the energy resolution has been calculated starting from the acquired data. With its compact and light geometry, high resolution and high sensitivity this detector has a promising layout as a preclinical PET scanner.