Euromedim 2006 :1st European Conference on Molecular Imaging Technology

RECENT TECHNOLOGIC DEVELOPMENTS ON HIGH RESOLUTION BETA IMAGING SYSTEMS FOR MOLECULAR IMAGING WITH MULTI-ISOTOPES LABELING APPLICATIONS

11 May 2006, 14:00

1h

Palais du Pharo, Marseille

poster Molecular Imaging needs for biologists and physicians Poster session : Imaging systems, Molecular Imaging

Speaker

Dr Nicole BARTHE (INSERM U577, Université Victor Segalen Bordeaux 2)

Description

Two novel betaimaging systems, particularly interesting in the field of radiopharmacology and molecular biology researches, were developed these last years: (1) a betaimager was derived from researches conducted by Pr Charpak at CERN. This parallel plate avalanche chamber is a direct detection system of  radioactivity, which is particularly adapted for qualitative and quantitative autoradiography. With this detector, autoradiographic techniques can be performed using classical pure emitters like 3H, 14C, 35S, …but also radionuclides, such as 99mTc, which are  emitters associated with low energy electrons while decaying. In fact the detector has a very low sensitivity to low-range  rays and only detects the electrons. The performance in the field of sensitivity (smallest activity detected: 0,007 cpm/mm2 for 3H and 0,01 for 14C), linearity (over a dynamic range of 104) and spatial resolution (50m for 3H or 99mTc ) gives a real interest to this system as a new imaging device. Its principle of detection is based on the analysis of light emitted during the interaction with an intensified CCD camera. (2) a micro imager is based on contact imaging through a solid scintillator sheet. Light emitted is amplified through an image intensifier tube and is analysed with a CCD camera. The full field of view is smaller than the first one (24mm x 32mm versus 20cm x 25cm) but a better spatial resolution is obtained (typically 15 m for 3H and 99mTc). The specifications of this detector are similar to the first ones with a slightly reduced sensitivity. Using these detectors, quantification is much easier and more precise than that of the radiological film because of direct counting of radioactivity. With new recent developments on these devices, it is possible to detect, in the same sample, two isotopes of different energies ( 3H and 14C for exemple ) or of different decaying periods ( 99mTc and 201Tl for exemple). Results obtained on biological experimentations for the development of different radiopharmaceuticals and interest of this new methodology in various applications, among which detection of positive electrons ( +: like those emitted by 18F, 15O or 11C ) will be detailed in this presentation.