PET instrumentation: what are the limits?

This report has emphasized the attributes of positron emission tomography (PET) through a discussion of the historical development with attention to limitations or factors that are of importance in using and further developing this technology. As is the case for all nuclear detector developments, the factors that require consideration are spatial resolution, uniformity of resolution, sensitivity, distortions (attenuation), background noise (scatter and randoms), image volume, data acquisition capabilities (count-rate saturation), and limitations based on allowable radiation doses to the subject. Forty years ago, the fact that dual gamma-cameras could not handle the count-rates from the short half-life radionuclides that had clinical applications at that time (ie, 15O, 11C, 13N) precluded their acceptance in nuclear medicine. With the advent of 18F applications particularly with FDG in oncology, this limitations was no longer a barrier. Twenty years ago and until recently, the promise of time-of-flight PET has been stifled by the fact that the appropriately fast scintillator BaF2 had too low an efficiency (low density) to be useful in improving the signal to noise of a time-of-flight tomograph over contemporary systems. With the development of dense scintillators with high light output and high speed such as LSO30 the time-of-flight potentials are now once again worth pursuing. Twenty years ago systems that theoretically would have improved sensitivity by minimal or no septa with spherical geometric arrangements of detectors were ignored because it appeared that scatter backgrounds would lead to a signal to noise less than 1. But in the last 5 years, cylindrical systems without speta have shown that noise effective sensitivity improvements of a factor of 4 can be realized. With time-of-flight additional improvements in sensitivity will be realized. Horizons for detector development include discovery of new scintillators, new methods of registering scintillation light, deployment of larger field of view systems and methods of compensating for scatter, randoms, attenuation, and irregular sampling associated with new geometries which can encircle most of the body. The expected limit for PET is 2 mm isotropic resolution for the head and appendages including joints and breasts. Clinical realization of this resolution for the thorax and abdomen requires compensation for motion and even in this area strategies are underdevelopment which rely on the improvement in sensitivity being realized by 3D systems.

[1]  J. Kuperus,et al.  Technology for FDG SPECT with a relatively inexpensive gamma camera. Work in progress. , 1994, Radiology.

[2]  R H Huesman,et al.  Dead time correction and counting statistics for positron tomography. , 1985, Physics in medicine and biology.

[3]  E. Hoffman,et al.  Correction and characterization of scattered events in three-dimensional PET using scanners with retractable septa. , 1993, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[4]  T F Budinger Instrumentation trends in nuclear medicine. , 1977, Seminars in nuclear medicine.

[5]  B E Oppenheim,et al.  Direct comparison of fluorine-18-FDG SPECT, fluorine-18-FDG PET and rest thallium-201 SPECT for detection of myocardial viability. , 1995, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[6]  Henry N. Wagner,et al.  Medical Radioisotope Scanning , 1960 .

[7]  M. Defrise,et al.  Three dimensional reconstruction of PET data from a multi-ring camera , 1989 .

[8]  G Muehllehner,et al.  Three-dimensional imaging characteristics of the HEAD PENN-PET scanner. , 1997, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[9]  S R Meikle,et al.  A convolution-subtraction scatter correction method for 3D PET. , 1994, Physics in medicine and biology.

[10]  G. J. Klein,et al.  Automated 3-D segmentation of respiratory-gated PET transmission images , 1997 .

[11]  W. W. Moses,et al.  A positron tomograph with 600 BGO crystals and 2.6 mm resolution , 1988 .

[12]  S. Mukherji,et al.  Comparison of thallium-201 and F-18 FDG SPECT uptake in squamous cell carcinoma of the head and neck. , 1994, AJNR. American journal of neuroradiology.

[13]  S. Webb,et al.  The performance of a multiwire proportional chamber positron camera for clinical use. , 1989, Physics in medicine and biology.

[14]  G T Gullberg,et al.  Quantitative potentials of dynamic emission computed tomography. , 1978, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[15]  C. Melcher,et al.  Cerium-doped lutetium oxyorthosilicate: a fast, efficient new scintillator , 1991, Conference Record of the 1991 IEEE Nuclear Science Symposium and Medical Imaging Conference.

[16]  S Aronow,et al.  A hybrid positron scanner. , 1970, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[17]  Jarritt Ph,et al.  PET imaging using gamma camera systems: a review. , 1996 .

[18]  Thomas K. Lewellen,et al.  Investigation of the count rate performance of General Electric Advance positron emission tomograph , 1995 .

[19]  Magnus Dahlbom,et al.  Investigation of LSO crystals for high spatial resolution positron emission tomography , 1996 .

[20]  Simon R. Cherry,et al.  Optimization of PET instrumentation for brain activation studies , 1992 .

[21]  F. Soussaline,et al.  A technique for the correction of scattered radiation in a PET system using time-of-flight information. , 1986, Journal of computer assisted tomography.

[22]  E. Hoffman,et al.  Fully three-dimensional reconstruction for a PET camera with retractable septa , 1991 .

[23]  B E Sobel,et al.  Influence of Cardiac and Respiratory Motion on Tomographic Reconstructions of the Heart: Implications for Quantitative Nuclear Cardiology , 1982, Journal of computer assisted tomography.

[24]  D. Bailey,et al.  3D acquisition and reconstruction in positron emission tomography , 1992, Annals of nuclear medicine.

[25]  S Grootoonk,et al.  A rotating PET scanner using BGO block detectors: design, performance and applications. , 1993, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[26]  M P Sandler,et al.  FDG-SPECT: correlation with FDG-PET. , 1995, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[27]  R. Trebossen,et al.  A PET scatter correction using simultaneous acquisitions with low and high lower energy thresholds , 1993, 1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference.

[28]  A Geissbuhler,et al.  Implementation of three-dimensional image reconstruction for multi-ring positron tomographs. , 1990, Physics in medicine and biology.

[29]  E. Hoffman,et al.  A BOUNDARY METHOD FOR ATTENUATION CORRECTION IN POSITRON COMPUTED TOMOGRAPHY , 1981, Journal of Nuclear Medicine.

[30]  E. Hoffman,et al.  A positron-emission transaxial tomograph for nuclear imaging (PETT). , 1975, Radiology.

[31]  Ronald H. Huesman,et al.  The Donner 280-Crystal High Resolution Positron Tomograph , 1979, IEEE Transactions on Nuclear Science.

[32]  M R Palmer,et al.  Scatter distribution in transmission measurements with positron emission tomography. , 1986, Journal of computer assisted tomography.

[33]  E. Hoffman,et al.  An investigation of scatter in attenuation correction for PET , 1989 .

[34]  M. Ter-pogossian,et al.  Feasibility of time-of-flight reconstruction in positron emission tomography. , 1980, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[35]  Thomas K. Lewellen,et al.  Investigation of the performance of the General Electric Advance positron emission tomograph in 3D mode , 1995 .

[36]  E. Hoffman,et al.  Measuring PET scanner sensitivity: relating countrates to image signal-to-noise ratios using noise equivalents counts , 1990 .

[37]  E. Hoffman,et al.  Application of annihilation coincidence detection to transaxial reconstruction tomography. , 1975, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[38]  Magnus Dahlbom,et al.  Performance of a YSO/LSO phoswich detector for use in a PET/SPECT system , 1997 .

[39]  S. Grootoonk,et al.  Correction for scatter using a dual energy window technique with a tomograph operated without septa , 1991, Conference Record of the 1991 IEEE Nuclear Science Symposium and Medical Imaging Conference.

[40]  Christopher J. Thompson The effect of collimation on single rates in multi-slice PET , 1989 .

[41]  M. Defrise,et al.  Favor: a fast reconstruction algorithm for volume imaging in PET , 1991, Conference Record of the 1991 IEEE Nuclear Science Symposium and Medical Imaging Conference.

[42]  R H Huesman,et al.  The effects of a finite number of projection angles and finite lateral sampling of projections on the propagation of statistical errors in transverse section reconstruction. , 1977, Physics in medicine and biology.

[43]  Thomas K. Lewellen,et al.  An experimental evaluation of the effect of time-of-flight information in image reconstructions for the Scanditronix/PETT Electronics SP-3000 positron emission tomograph-preliminary results , 1989 .

[44]  T. Budinger,et al.  Three-dimensional reconstruction in nuclear medicine emission imaging , 1974 .

[45]  V. Perez-Mendez,et al.  Axial Tomography and Three Dimensional Image Reconstruction , 1976, IEEE Transactions on Nuclear Science.

[46]  L. Kaufman,et al.  Initial Characterization of a Multi-Wire Proportional Chamber Positron Camera , 1975, IEEE Transactions on Nuclear Science.

[47]  R L Wahl,et al.  Untreated lung cancer: quantification of systematic distortion of tumor size and shape on non-attenuation-corrected 2-[fluorine-18]fluoro-2-deoxy-D-glucose PET scans. , 1996, Radiology.

[48]  Ronald H. Huesman,et al.  Imaging Properties of a Positron Tomograph with 280 Bgo Crystals , 1981, IEEE Transactions on Nuclear Science.

[49]  R. Wahl,et al.  Triple-head SPECT with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG): initial evaluation in oncology and comparison with FDG PET. , 1995, Radiology.

[50]  W. Martin,et al.  Detection of malignancies with SPECT versus PET, with 2-[fluorine-18]fluoro-2-deoxy-D-glucose. , 1996, Radiology.

[51]  G Muehllehner,et al.  Positron camera with extended counting rate capability. , 1975, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[52]  J. K. Chan,et al.  Circular Ring Transverse Axial Positron Camera for 3-Dimensional Reconstruction of Radionuclides Distribution , 1976, IEEE Transactions on Nuclear Science.

[53]  H. G. Jackson,et al.  High Resolution Computed Tomography of Positron Emitters , 1976, IEEE Transactions on Nuclear Science.

[54]  S. Derenzo,et al.  Application of mathematical removal of positron range blurring in positron emission tomography , 1990 .

[55]  Victor Perez-Mendez,et al.  3-D Object Reconstruction in Emission and Transmission Tomography with Limited Angular Input , 1979, IEEE Transactions on Nuclear Science.

[56]  C. Bohm,et al.  Correction for Scattered Radiation in a Ring Detector Positron Camera by Integral Transformation of the Projections , 1983, Journal of computer assisted tomography.

[57]  W. A. Higinbotham,et al.  POSITRON SCANNER FOR LOCATING BRAIN TUMORS , 1961 .

[58]  M. Bergström,et al.  Positron emission tomography (PET) in neuroendocrine gastrointestinal tumors. , 1993, Acta oncologica.

[59]  M E Phelps,et al.  Whole-body positron emission tomography: Part I. Methods and performance characteristics. , 1992, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[60]  R. Q. Edwards,et al.  Image Separation Radioisotope Scanning , 1963 .

[61]  W. Moses,et al.  Orbiting transmission source for positron tomography , 1988 .

[62]  W. W. Moses,et al.  PET detector modules based on novel detector technologies , 1994 .

[63]  J. Ollinger Model-based scatter correction for fully 3D PET. , 1996, Physics in medicine and biology.

[64]  Robert S. Miyaoka,et al.  A data acquisition system for coincidence imaging using a conventional dual head gamma camera , 1996 .

[65]  J. Colsher,et al.  Fully-three-dimensional positron emission tomography , 1980, Physics in medicine and biology.

[66]  M. Gilardi,et al.  Noise Equivalent Count Measurements In A Neuro-pet Scanner With Retractable SEPTA , 1990, 1990 IEEE Nuclear Science Symposium Conference Record.

[67]  Thomas F. Budinger,et al.  MIRD primer for absorbed dose calculations , 1988 .

[68]  Paul Kinahan,et al.  Analytic 3D image reconstruction using all detected events , 1989 .

[69]  A. Rodríguez-Antúnez Recent Advances in Nuclear Medicine , 1973 .