Nuclear cardiac imaging is a noninvasive, sensitive method providing information on cardiac struc... more Nuclear cardiac imaging is a noninvasive, sensitive method providing information on cardiac structure and physiology. Single photon emission tomography (SPECT) evaluates myocardial perfusion, viability, and function and is widely used in clinical routine. The quality of the tomographic image is a key for accurate diagnosis. Image filtering, a mathematical processing, compensates for loss of detail in an image while reducing image noise, and it can improve the image resolution and limit the degradation of the image. SPECT images are then reconstructed, either by filter back projection (FBP) analytical technique or iteratively, by algebraic methods. The aim of this study is to review filters in cardiac 2D, 3D, and 4D SPECT applications and how these affect the image quality mirroring the diagnostic accuracy of SPECT images. Several filters, including the Hanning, Butterworth, and Parzen filters, were evaluated in combination with the two reconstruction methods as well as with a specified MatLab program. Results showed that for both 3D and 4D cardiac SPECT the Butterworth filter, for different critical frequencies and orders, produced the best results. Between the two reconstruction methods, the iterative one might be more appropriate for cardiac SPECT, since it improves lesion detectability due to the significant improvement of image contrast.
Single photon emission computed tomography (SPECT) imaging is widely implemented in nuclear medic... more Single photon emission computed tomography (SPECT) imaging is widely implemented in nuclear medicine as its clinical role in the diagnosis and management of several diseases is, many times, very helpful (e.g., myocardium perfusion imaging). The quality of SPECT images are degraded by several factors such as noise because of the limited number of counts, attenuation, or scatter of photons. Image filtering is necessary to compensate these effects and, therefore, to improve image quality. The goal of filtering in tomographic images is to suppress statistical noise and simultaneously to preserve spatial resolution and contrast. The aim of this work is to describe the most widely used filters in SPECT applications and how these affect the image quality. The choice of the filter type, the cut-off frequency and the order is a major problem in clinical routine. In many clinical cases, information for specific parameters is not provided, and findings cannot be extrapolated to other similar SPECT imaging applications. A literature review for the determination of the mostly used filters in cardiac, brain, bone, liver, kidneys, and thyroid applications is also presented. As resulting from the overview, no filter is perfect, and the selection of the proper filters, most of the times, is done empirically. The standardization of image-processing results may limit the filter types for each SPECT examination to certain few filters and some of their parameters. Standardization, also, helps in reducing image processing time, as the filters and their parameters must be standardised before being put to clinical use. Commercial reconstruction software selections lead to comparable results interdepartmentally. The manufacturers normally supply default filters/parameters, but these may not be relevant in various clinical situations. After proper standardisation, it is possible to use many suitable filters or one optimal filter.
Nuclear Medicine provides efficient tools for cancer therapy using compounds labelled with radion... more Nuclear Medicine provides efficient tools for cancer therapy using compounds labelled with radionuclides that emit beta-particles, alpha-particles or Auger electrons. With their short path lengths, they destroy mainly targeted cancer cells with limited side effects. Ideal application for targeted radionuclide therapy demands radionuclides' physical, radiobiological and radiochemical properties to be well known. These radionuclides are produced with the desirable characteristics for their application in Nuclear Medicine radiopharmaceutical therapy.
Receptor Radionuclide Therapy (PRRT) for neuroendocrine tumors. Radiolabelled somatostatin analog... more Receptor Radionuclide Therapy (PRRT) for neuroendocrine tumors. Radiolabelled somatostatin analogue [ 177 Lu-DOTA 0 , Tyr 3 ] octreotate stands as a promising therapy tool. Specific dosimetry is a crucial factor in patient treatment planning. Dosimetric techniques implemented in our Institution are presented.
Nuclear cardiac imaging is a noninvasive, sensitive method providing information on cardiac struc... more Nuclear cardiac imaging is a noninvasive, sensitive method providing information on cardiac structure and physiology. Single photon emission tomography (SPECT) evaluates myocardial perfusion, viability, and function and is widely used in clinical routine. The quality of the tomographic image is a key for accurate diagnosis. Image filtering, a mathematical processing, compensates for loss of detail in an image while reducing image noise, and it can improve the image resolution and limit the degradation of the image. SPECT images are then reconstructed, either by filter back projection (FBP) analytical technique or iteratively, by algebraic methods. The aim of this study is to review filters in cardiac 2D, 3D, and 4D SPECT applications and how these affect the image quality mirroring the diagnostic accuracy of SPECT images. Several filters, including the Hanning, Butterworth, and Parzen filters, were evaluated in combination with the two reconstruction methods as well as with a specified MatLab program. Results showed that for both 3D and 4D cardiac SPECT the Butterworth filter, for different critical frequencies and orders, produced the best results. Between the two reconstruction methods, the iterative one might be more appropriate for cardiac SPECT, since it improves lesion detectability due to the significant improvement of image contrast.
Single photon emission computed tomography (SPECT) imaging is widely implemented in nuclear medic... more Single photon emission computed tomography (SPECT) imaging is widely implemented in nuclear medicine as its clinical role in the diagnosis and management of several diseases is, many times, very helpful (e.g., myocardium perfusion imaging). The quality of SPECT images are degraded by several factors such as noise because of the limited number of counts, attenuation, or scatter of photons. Image filtering is necessary to compensate these effects and, therefore, to improve image quality. The goal of filtering in tomographic images is to suppress statistical noise and simultaneously to preserve spatial resolution and contrast. The aim of this work is to describe the most widely used filters in SPECT applications and how these affect the image quality. The choice of the filter type, the cut-off frequency and the order is a major problem in clinical routine. In many clinical cases, information for specific parameters is not provided, and findings cannot be extrapolated to other similar SPECT imaging applications. A literature review for the determination of the mostly used filters in cardiac, brain, bone, liver, kidneys, and thyroid applications is also presented. As resulting from the overview, no filter is perfect, and the selection of the proper filters, most of the times, is done empirically. The standardization of image-processing results may limit the filter types for each SPECT examination to certain few filters and some of their parameters. Standardization, also, helps in reducing image processing time, as the filters and their parameters must be standardised before being put to clinical use. Commercial reconstruction software selections lead to comparable results interdepartmentally. The manufacturers normally supply default filters/parameters, but these may not be relevant in various clinical situations. After proper standardisation, it is possible to use many suitable filters or one optimal filter.
Nuclear Medicine provides efficient tools for cancer therapy using compounds labelled with radion... more Nuclear Medicine provides efficient tools for cancer therapy using compounds labelled with radionuclides that emit beta-particles, alpha-particles or Auger electrons. With their short path lengths, they destroy mainly targeted cancer cells with limited side effects. Ideal application for targeted radionuclide therapy demands radionuclides' physical, radiobiological and radiochemical properties to be well known. These radionuclides are produced with the desirable characteristics for their application in Nuclear Medicine radiopharmaceutical therapy.
Receptor Radionuclide Therapy (PRRT) for neuroendocrine tumors. Radiolabelled somatostatin analog... more Receptor Radionuclide Therapy (PRRT) for neuroendocrine tumors. Radiolabelled somatostatin analogue [ 177 Lu-DOTA 0 , Tyr 3 ] octreotate stands as a promising therapy tool. Specific dosimetry is a crucial factor in patient treatment planning. Dosimetric techniques implemented in our Institution are presented.
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