The time of flight information (TOF) is used in ''TTVOl'', a PET system built by ... more The time of flight information (TOF) is used in ''TTVOl'', a PET system built by the French LETI group and installed in Orsay, where clinical studies and physical measurements are performed. Given the TOF sampling interval (12 mm), experiments showed that in three cases out of four a point source located in a scattering medium yielded the same TOF value for both scattered and true events. One can thus assume that the scatter component is mainly due to single scattering of one of the two photons occurring near the positron source. This scatter fraction was approximated by a 2D function which is position independent except for sources near the edge of the object. This function was added to the TOF response of the system and the deconvolution filter was derived from the modified response. It was tested on two 68-Ga filled cylindrical phantoms (24 and 30 cm in diameter). The first one contained three cold cylinders (4, 5, 7 cm in diameter) placed 6 cm off center and the ...
SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 - Gif-sur-Yvette Cedex (France) /... more SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 - Gif-sur-Yvette Cedex (France) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / I... more SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / I... more SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
A process and appparatus for obtaining three-dimensional images of an object with an application ... more A process and appparatus for obtaining three-dimensional images of an object with an application of the process and the device to the tomography of an organ. The device includes a detector or mobile rays which rotates about the object and mechanisms which provide references for the angular position of the detector with respect to the reference plane. The detector contains detection areas which receive the radiation and are identified by their number and emit signals, the amplitude of which depends on the intensity of the received rays. Also included in the device is an iterative processing machine which operates by convergent processing of the signal amplitude values with the processing mechanism being connecting to visualization devices in order to display the images of the object in various cross-section planes after each iteration.
The greatest interest in positron emission computerized tomography (PCT) can be understood from i... more The greatest interest in positron emission computerized tomography (PCT) can be understood from its unique potential to provide non-traumatic in vivo visualization and quantification of tissue concentrations of administered radiopharmaceuticals on a regional basis. This means the study of metabolic and physiologic mechanisms in man, when combined with tracers of physiologic process correct models and adequate instruments for detection, and data reconstruction. The scope of this paper is focused on a few specific points in relation with the production of short lived positron emitters and radiopharmaceuticals, the positron emitters tomographic detection system and some medical applications under development in a few clinical centers, and, in particular, at Orsay (SHFJ).
The time of flight information (TOF) is used in ''TTVOl'', a PET system built by ... more The time of flight information (TOF) is used in ''TTVOl'', a PET system built by the French LETI group and installed in Orsay, where clinical studies and physical measurements are performed. Given the TOF sampling interval (12 mm), experiments showed that in three cases out of four a point source located in a scattering medium yielded the same TOF value for both scattered and true events. One can thus assume that the scatter component is mainly due to single scattering of one of the two photons occurring near the positron source. This scatter fraction was approximated by a 2D function which is position independent except for sources near the edge of the object. This function was added to the TOF response of the system and the deconvolution filter was derived from the modified response. It was tested on two 68-Ga filled cylindrical phantoms (24 and 30 cm in diameter). The first one contained three cold cylinders (4, 5, 7 cm in diameter) placed 6 cm off center and the ...
Analytical cellular pathology : the journal of the European Society for Analytical Cellular Pathology, 1991
A semi-automatic program, designed for non-computer scientists, was developed for quantification ... more A semi-automatic program, designed for non-computer scientists, was developed for quantification of RNA levels detected by in situ hybridization in heterogeneous tissues. A video camera was used to acquire microscopic images of autoradiographed tissue sections which are then digitized on a video monitor for semi-automated quantification of silver grains. We describe a data entry and analysis procedure for systematic quantification of RNA levels in which about 300 cells per tissue sample can be analysed within 10 min. When compared with visual counting, computer-aided quantification was found to be more objective and reliable, with the highest variation coefficient between individuals being 7.5% using computer-aided quantification, compared to 24% with manual counting of the same section areas. A comparative study of c-myc oncogene expression in 11 mammary adenocarcinomas from 3 independent experiments showed the good reproducibility of results using the computer-aided method, with a...
The problem of successive transverse plane reconstruction in single photon emission computerized ... more The problem of successive transverse plane reconstruction in single photon emission computerized tomography (SPECT) is modeled in its more general form, which implies the definition of emission tomographic operators (ETO's) for which an analytical solution can be derived. The properties of the attenuated tomographic operator (ATO) are described and discussed, including the attenuation which is distributed on the reconstruction domain. For this particular operator, a regularizing method (RIM) is proposed, for which it is demonstrated and tested with simulation studies that a filtered, accurate solution can be extracted for the tomographic images as obtained using a single photon emission tomograph based on a rotating gamma camera in clinical use.
The time of flight information (TOF) is used in ''TTVOl'', a PET system built by ... more The time of flight information (TOF) is used in ''TTVOl'', a PET system built by the French LETI group and installed in Orsay, where clinical studies and physical measurements are performed. Given the TOF sampling interval (12 mm), experiments showed that in three cases out of four a point source located in a scattering medium yielded the same TOF value for both scattered and true events. One can thus assume that the scatter component is mainly due to single scattering of one of the two photons occurring near the positron source. This scatter fraction was approximated by a 2D function which is position independent except for sources near the edge of the object. This function was added to the TOF response of the system and the deconvolution filter was derived from the modified response. It was tested on two 68-Ga filled cylindrical phantoms (24 and 30 cm in diameter). The first one contained three cold cylinders (4, 5, 7 cm in diameter) placed 6 cm off center and the ...
SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 - Gif-sur-Yvette Cedex (France) /... more SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 - Gif-sur-Yvette Cedex (France) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / I... more SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / I... more SIGLEAvailable from CEN Saclay, Service de Documentation, 91191 Gif-sur-Yvette Cedex (France) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
A process and appparatus for obtaining three-dimensional images of an object with an application ... more A process and appparatus for obtaining three-dimensional images of an object with an application of the process and the device to the tomography of an organ. The device includes a detector or mobile rays which rotates about the object and mechanisms which provide references for the angular position of the detector with respect to the reference plane. The detector contains detection areas which receive the radiation and are identified by their number and emit signals, the amplitude of which depends on the intensity of the received rays. Also included in the device is an iterative processing machine which operates by convergent processing of the signal amplitude values with the processing mechanism being connecting to visualization devices in order to display the images of the object in various cross-section planes after each iteration.
The greatest interest in positron emission computerized tomography (PCT) can be understood from i... more The greatest interest in positron emission computerized tomography (PCT) can be understood from its unique potential to provide non-traumatic in vivo visualization and quantification of tissue concentrations of administered radiopharmaceuticals on a regional basis. This means the study of metabolic and physiologic mechanisms in man, when combined with tracers of physiologic process correct models and adequate instruments for detection, and data reconstruction. The scope of this paper is focused on a few specific points in relation with the production of short lived positron emitters and radiopharmaceuticals, the positron emitters tomographic detection system and some medical applications under development in a few clinical centers, and, in particular, at Orsay (SHFJ).
The time of flight information (TOF) is used in ''TTVOl'', a PET system built by ... more The time of flight information (TOF) is used in ''TTVOl'', a PET system built by the French LETI group and installed in Orsay, where clinical studies and physical measurements are performed. Given the TOF sampling interval (12 mm), experiments showed that in three cases out of four a point source located in a scattering medium yielded the same TOF value for both scattered and true events. One can thus assume that the scatter component is mainly due to single scattering of one of the two photons occurring near the positron source. This scatter fraction was approximated by a 2D function which is position independent except for sources near the edge of the object. This function was added to the TOF response of the system and the deconvolution filter was derived from the modified response. It was tested on two 68-Ga filled cylindrical phantoms (24 and 30 cm in diameter). The first one contained three cold cylinders (4, 5, 7 cm in diameter) placed 6 cm off center and the ...
Analytical cellular pathology : the journal of the European Society for Analytical Cellular Pathology, 1991
A semi-automatic program, designed for non-computer scientists, was developed for quantification ... more A semi-automatic program, designed for non-computer scientists, was developed for quantification of RNA levels detected by in situ hybridization in heterogeneous tissues. A video camera was used to acquire microscopic images of autoradiographed tissue sections which are then digitized on a video monitor for semi-automated quantification of silver grains. We describe a data entry and analysis procedure for systematic quantification of RNA levels in which about 300 cells per tissue sample can be analysed within 10 min. When compared with visual counting, computer-aided quantification was found to be more objective and reliable, with the highest variation coefficient between individuals being 7.5% using computer-aided quantification, compared to 24% with manual counting of the same section areas. A comparative study of c-myc oncogene expression in 11 mammary adenocarcinomas from 3 independent experiments showed the good reproducibility of results using the computer-aided method, with a...
The problem of successive transverse plane reconstruction in single photon emission computerized ... more The problem of successive transverse plane reconstruction in single photon emission computerized tomography (SPECT) is modeled in its more general form, which implies the definition of emission tomographic operators (ETO's) for which an analytical solution can be derived. The properties of the attenuated tomographic operator (ATO) are described and discussed, including the attenuation which is distributed on the reconstruction domain. For this particular operator, a regularizing method (RIM) is proposed, for which it is demonstrated and tested with simulation studies that a filtered, accurate solution can be extracted for the tomographic images as obtained using a single photon emission tomograph based on a rotating gamma camera in clinical use.
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Papers by F. Soussaline