We present an improved partial wave analysis of the dominant LSP annihilation channel to a fermio... more We present an improved partial wave analysis of the dominant LSP annihilation channel to a fermion-antifermion pair which avoids the non-relativistic expansion being therefore applicable near thresholds and poles. The method we develop allows of contributions of any partial wave in the total angular momentum J in contrast to partial wave analyses in terms of the orbital angular momentum L of the initial state, which is usually truncated to p-waves, and yields very accurate results. The method is formulated in such a way as to allow easy handling of CP-violating phases residing in supersymmetric parameters. We apply this refined partial wave technique in order to calculate the neutralino relic density in the constrained MSSM (CMSSM) in the presence of CP-violating terms occurring in the Higgs-mixing parameter µ and trilinear A coupling for large tan β. The inclusion of CP-violating phases in µ and A does not upset significantly the picture and the annihilation of the LSP's to a bb, through Higgs exchange, is still the dominant mechanism in obtaining cosmologically acceptable neutralino relic densities in regions far from the stau-coannihilation and the 'focus point'. Significant changes can occur if we allow for phases in the gaugino masses and in particular the gluino mass.
Introduction: Low-dose Whole Body Multi-Detector Computed Tomography (MDCT) has been established ... more Introduction: Low-dose Whole Body Multi-Detector Computed Tomography (MDCT) has been established as an alternative to conventional X-ray imaging for Multiple Myeloma (MM) diagnosis. During an MDCT scan two dose indices are displayed on the monitor to account for the dose delivered to the patient: the volume computed tomography dose index (CTDI vol) and the dose length product (DLP). Both parameters though, are not sufficient in estimating the actual dose on their own. Two methods are proposed to promptly evaluate the scan dose, based on the two indices displayed: an effective dose evaluation through the DLP (Huda et al, 2008) and the Size-Specific Dose Estimate (SSDE), which also takes into account the patient's size, based on the CTDI vol (AAPM Report 204). Material and method: In this study a standardized protocol was developed and data from a good number of clinical examinations were collected. Effective dose was calculated based on the scanner displayed DLP. SSDE calculations were based on the scanner displayed values for the CTDI vol. SSDE is the averaged patient dose within the scan volume corrected for patient size. Dose is estimated using both methods for a set of 85 patients, examined for MM, for the torso body part. Although these indices are quite different in principle, they both present a rough but fast and prompt evaluation of the delivered dose. The results of the two methods are presented and evaluated. Result: Calculated ED and SSDE values were found to present a weak correlation. Pairwise comparisons showed that the dose values through the two methods differed significantly (P < 0.001) by (0.92 ± 0.79) mSv. The Bland-Altman plot showed that the 95% LOA is 3.1 mSv wide, yelding a relatively poor agreement between the two methods. Conclusion: The two methods of evaluation of the CT scan dose indices, ED and SSDE, based on DLP and CTDI vol correspondingly, provide an easily applicable dose estimation of a CT scan, but their values are found to present a notable difference. This means that they can not be used interchangeably clinically, but the most appropriate one should be used accordingly. ED relies on standardized phantoms and therefore has shortcomings with respect to its ability to reflect any individual patient effective dose. The SSDE is a good tool for estimating the average radiation dose for a given patient depending on the input parameters and the dimensions of the specific person in question but does not incorporate any organ/tissue weighting factors. It is recommended that when examined patients deviate significantly from the reference person by ICRP, dose should be estimated through the SSDE method. It is also proposed that tissue weighting factors would be incorporated with the SSDE methodology to provide a more refined estimate of risk.
We explore in detail the consequences of the CP-violating phases residing in the supersymmetric a... more We explore in detail the consequences of the CP-violating phases residing in the supersymmetric and soft SUSY breaking parameters in the approximation that family flavour mixings are ignored. We allow for non-universal boundary conditions and in such a consideration the model is described by twelve independent CP-violating phases and one angle which misaligns the vacuum expectation values (VEVs) of the Higgs scalars. We run two-loop renormalization group equations (RGEs), for all parameters involved, including phases, and we properly treat the minimization conditions using the one-loop effective potential with CPviolating phases included. We show that the two-loop running of phases may induce sizable effects for the electric dipole moments (EDMs) that are absent in the one-loop RGE analysis. Also important corrections to the EDMs are induced by the Higgs VEVs misalignment angle which are sizable in the large tan β region. Scanning the available parameter space we seek regions compatible with accelerator and cosmological data with emphasis on rapid neutralino annihilations through a Higgs resonance. It is shown that large CP-violating phases, as required in Baryogenesis scenarios, can be tuned to obtain agreement with WMAP3 cold dark matter constraints, EDMs and all available accelerator data, in extended regions of the parameter space which may be accessible to LHC.
Rhenium-186 (Re-186) is a β-emitting radionuclide. Emitted β-particles have ranges up to 4.5 mm i... more Rhenium-186 (Re-186) is a β-emitting radionuclide. Emitted β-particles have ranges up to 4.5 mm in tissue, capable of delivering high doses to skeletal regions of high Re-186 concentrations while sparing adjacent radiosensitive regions and thus making the irradiation well tolerated for the patient. Along with the β-emissions, γ-rays are emitted having an adequate energy for imaging during therapy and biodistribution assessment for patient-specific dosimetry calculations. The relatively short physical half-life combined with the β-emissions allows the delivery of relatively high activity rate for a short period of time in areas of concentration. This study is a short review concerning the palliative treatment of skeletal metastases using 186Re-HEDP. After presenting the dominant ways of 186Re production, special emphasis is given to dosimetry issues while the effect of palliation therapy can be evaluated through the comparison of the absorbed dose in metastatic lesion relatively to t...
Background: Lung cancer screening (LCS) with annual chest low-dose CT (LDCT) has been recently re... more Background: Lung cancer screening (LCS) with annual chest low-dose CT (LDCT) has been recently recommended for individuals aged 55-80 years at high risk of lung cancer. This study aims at determining the radiation burden and the lifetime attributable risk (LAR) of radiation-induced cancer in individuals undergoing 256-slice LDTC for LCS purposes. Methods: Chest 256-slice LDCT exposures were simulated on mathematical anthropomorphic phantoms of varying body mass index (BMI) using Monte Carlo methods. Normalized and absolute organ doses, as well as effective doses (ED), were estimated. Organ-specific and total cancer LARs were estimated using published age-and sex-specific risk factors. Cumulative LARs from repeated annual LDCT studies were estimated. Total LARs were compared to corresponding nominal lifetime intrinsic risks of cancer (LIRs). Lung cancer LAR was benchmarked against the intrinsic lung cancer risk associated with the screening population. Results: Lung and breast (females) are the organs receiving the highest doses from chest LDCT. Organ-based ED estimates were 0.76mSv and 0.53mSv for females and males of normal BMI, respectively. Absorbed organ doses and ED decrease considerably with BMI. A single chest LDCT exposure at 55 years is associated with 2.0 and 4.8 new cancer incidents per 10 5 average-sized males and females, respectively. The cumulative LAR of radiogenic cancer from repeated annual LDCT studies between the ages of 55 and 80 years was estimated to incur a relative increase in the LIR of being diagnosed with cancer by less than 0.3% and 0.1% in females and males, respectively. For average-sized males and females, repeated annual LDCT exposures lead to 25 and 59, respectively, new lung cancer cases per 10 5 LCS program participants. Discussion: Estimated radiation burden and theoretical radiogenic cancer risks associated with repeated annual 256-slice LDCT chest exposures may alleviate radiation-related concerns regarding the implementation of a LCS program. Provided a modern technology scanner and a carefully considered low-dose protocol are employed, total radiation-induced cancer risk seems to minimally aggravate the lifetime intrinsic cancer risk for the screening population. Furthermore, the radiogenic lung cancer risk constitutes only a minute fraction of the intrinsic high cancer risk associated with such a population.
Biomedical Journal of Scientific & Technical Research, 2019
Monte Carlo [MC] method is a modeling tool, capable of achieving a close adherence to reality, co... more Monte Carlo [MC] method is a modeling tool, capable of achieving a close adherence to reality, concerning the analysis of complex systems. Generally is a method for estimation of the solution of mathematical problems by means of random numbers
We present an improved partial wave analysis of the dominant LSP annihilation channel to a fermio... more We present an improved partial wave analysis of the dominant LSP annihilation channel to a fermion-antifermion pair which avoids the non-relativistic expansion being therefore applicable near thresholds and poles. The method we develop allows of contributions of any partial wave in the total angular momentum J in contrast to partial wave analyses in terms of the orbital angular momentum L of the initial state, which is usually truncated to p-waves, and yields very accurate results. The method is formulated in such a way as to allow easy handling of CP-violating phases residing in supersymmetric parameters. We apply this refined partial wave technique in order to calculate the neutralino relic density in the constrained MSSM (CMSSM) in the presence of CP-violating terms occurring in the Higgs-mixing parameter µ and trilinear A coupling for large tan β. The inclusion of CP-violating phases in µ and A does not upset significantly the picture and the annihilation of the LSP's to a bb, through Higgs exchange, is still the dominant mechanism in obtaining cosmologically acceptable neutralino relic densities in regions far from the stau-coannihilation and the 'focus point'. Significant changes can occur if we allow for phases in the gaugino masses and in particular the gluino mass.
Rhenium-188 (Re-188) is a high energy β-emitting radioisotope obtained from the tungsten-188/rhen... more Rhenium-188 (Re-188) is a high energy β-emitting radioisotope obtained from the tungsten-188/rhenium-188 (W-188/Re-188) generator, which has shown utility for a variety of therapeutic applications in nuclear medicine, oncology, and interventional radiology/cardiology. Re-188 decay is accompanied by a 155 keV predominant energy γ-emission, which could be detected by γ-cameras, for imaging, biodistribution, or absorbed radiation dose studies. Its attractive physical properties and its potential low cost associated with a long-lived parent make it an interesting option for clinical use. The setup and daily use of W-188/Re-188 generator in hospital nuclear medicine departments are discussed in detail. The clinical efficacy, for several therapeutic applications, of a variety of Re-188-labeled agents is demonstrated. The high energy of the β-emission of Re-188 is particularly well suited for effective penetration in solid tumours. Its total radiation dose delivered to tissues is comparabl...
We explore in detail the consequences of the CP-violating phases residing in the supersymmetric a... more We explore in detail the consequences of the CP-violating phases residing in the supersymmetric and soft SUSY breaking parameters in the approximation that family flavour mixings are ignored. We allow for non-universal boundary conditions and in such a consideration the model is described by twelve independent CP-violating phases and one angle which misaligns the vacuum expectation values (VEVs) of the Higgs scalars. We run two-loop renormalization group equations (RGEs), for all parameters involved, including phases, and we properly treat the minimization conditions using the one-loop effective potential with CPviolating phases included. We show that the two-loop running of phases may induce sizable effects for the electric dipole moments (EDMs) that are absent in the one-loop RGE analysis. Also important corrections to the EDMs are induced by the Higgs VEVs misalignment angle which are sizable in the large tanβ region. Scanning the available parameter space we seek regions compati...
The aim of this work consists of modeling the left ventricle of the heart, at stress and rest sit... more The aim of this work consists of modeling the left ventricle of the heart, at stress and rest situation, using the myocardial scintigraphic data obtained in 3D stress/rest images and focuses on the possibility of quantification of differences. 32 cardiac patients completed stress and rest tests by Tc99m tetrofosmin in one-day protocol by a GE-Starcam-4000 gammacamera; Images of myocardium were reconstructed by the GE Volumetrix software in the GE Xeleris processing system. Myocardial perfusion was estimated by all (Short axis, HLA (Horizontal Long Axis) and VLA (Vertical Long Axis)) SPECT slices. For each patient, 2 series of transverse slices by tomographic image reconstruction, were produced, using OSEM iterative algorithm. DICOM data was extracted for each patient and an algorithm that integrates 3D visualization has been used for image processing analysis by MatLabR2012b. The appropriate threshold value was identified by creating intensity isocontours. The myocardium volume was evaluated and reconstructed as 3D image and calculations of the differences between the rest and stress data of the 3D images were made. An index ratio of the Volume of Interest (VOI) was determined. The differences between 3D images at rest and stress situations provide us with visual and quantitative evaluation of myocardial perfusion.
The aim of this study is to examine the impact of dark signal on assessing the image quality in c... more The aim of this study is to examine the impact of dark signal on assessing the image quality in computerized mammography. A GE analogue mammography unit was calibrated to be used with an Agfa CR35-X system. Tests for quality control were performed and Image Plates (IPs) were erased by the CR system. All IPs were first exposed to known amounts of scatter radiation and then used to take mammographic images of phantoms with varying density (a PASMAM-1054 Phantom with PMMA and Al inserts). Since high Signal-to-noise ratio (SNR) and high Contrast-to-noise ratio (CNR) are of great importance in mammographic image quality, we measured SNR and CNR of the taken images. Our results show the effect of scatter radiation on SNR and CNR. Scatter radiation increases SNR and decreases CNR. The impact of background signal was found not to be negligible. Dark signal deteriorates image quality in CR mammography. Consequently, further investigation may be warranted and daily erasure of the IPs is recom...
Rhenium-188 (Re-188) is a high energy β-emitting radioisotope obtained from the tungsten-188/rhen... more Rhenium-188 (Re-188) is a high energy β-emitting radioisotope obtained from the tungsten-188/rhenium-188 (W-188/Re-188) generator, which has shown utility for a variety of therapeutic applications in nuclear medicine, oncology, and interventional radiology/cardiology. Re-188 decay is accompanied by a 155 keV predominant energy γ-emission, which could be detected by γ-cameras, for imaging, biodistribution, or absorbed radiation dose studies. Its attractive physical properties and its potential low cost associated with a long-lived parent make it an interesting option for clinical use. The setup and daily use of W-188/Re-188 generator in hospital nuclear medicine departments are discussed in detail. The clinical efficacy, for several therapeutic applications, of a variety of Re-188-labeled agents is demonstrated. The high energy of the β-emission of Re-188 is particularly well suited for effective penetration in solid tumours. Its total radiation dose delivered to tissues is comparabl...
Purpose: The aim of this work consists of a method of determination of the thyroid gland's volume... more Purpose: The aim of this work consists of a method of determination of the thyroid gland's volume using the SPECT data in order to calculate the absorbed patient dose from the radioactive substances injected to the patient during thyroid treatment.
We present an improved partial wave analysis of the dominant LSP annihilation channel to a fermio... more We present an improved partial wave analysis of the dominant LSP annihilation channel to a fermion-antifermion pair which avoids the non-relativistic expansion being therefore applicable near thresholds and poles. The method we develop allows of contributions of any partial wave in the total angular momentum J in contrast to partial wave analyses in terms of the orbital angular momentum L of the initial state, which is usually truncated to p-waves, and yields very accurate results. The method is formulated in such a way as to allow easy handling of CP-violating phases residing in supersymmetric parameters. We apply this refined partial wave technique in order to calculate the neutralino relic density in the constrained MSSM (CMSSM) in the presence of CP-violating terms occurring in the Higgs-mixing parameter µ and trilinear A coupling for large tan β. The inclusion of CP-violating phases in µ and A does not upset significantly the picture and the annihilation of the LSP's to a bb, through Higgs exchange, is still the dominant mechanism in obtaining cosmologically acceptable neutralino relic densities in regions far from the stau-coannihilation and the 'focus point'. Significant changes can occur if we allow for phases in the gaugino masses and in particular the gluino mass.
Introduction: Low-dose Whole Body Multi-Detector Computed Tomography (MDCT) has been established ... more Introduction: Low-dose Whole Body Multi-Detector Computed Tomography (MDCT) has been established as an alternative to conventional X-ray imaging for Multiple Myeloma (MM) diagnosis. During an MDCT scan two dose indices are displayed on the monitor to account for the dose delivered to the patient: the volume computed tomography dose index (CTDI vol) and the dose length product (DLP). Both parameters though, are not sufficient in estimating the actual dose on their own. Two methods are proposed to promptly evaluate the scan dose, based on the two indices displayed: an effective dose evaluation through the DLP (Huda et al, 2008) and the Size-Specific Dose Estimate (SSDE), which also takes into account the patient's size, based on the CTDI vol (AAPM Report 204). Material and method: In this study a standardized protocol was developed and data from a good number of clinical examinations were collected. Effective dose was calculated based on the scanner displayed DLP. SSDE calculations were based on the scanner displayed values for the CTDI vol. SSDE is the averaged patient dose within the scan volume corrected for patient size. Dose is estimated using both methods for a set of 85 patients, examined for MM, for the torso body part. Although these indices are quite different in principle, they both present a rough but fast and prompt evaluation of the delivered dose. The results of the two methods are presented and evaluated. Result: Calculated ED and SSDE values were found to present a weak correlation. Pairwise comparisons showed that the dose values through the two methods differed significantly (P < 0.001) by (0.92 ± 0.79) mSv. The Bland-Altman plot showed that the 95% LOA is 3.1 mSv wide, yelding a relatively poor agreement between the two methods. Conclusion: The two methods of evaluation of the CT scan dose indices, ED and SSDE, based on DLP and CTDI vol correspondingly, provide an easily applicable dose estimation of a CT scan, but their values are found to present a notable difference. This means that they can not be used interchangeably clinically, but the most appropriate one should be used accordingly. ED relies on standardized phantoms and therefore has shortcomings with respect to its ability to reflect any individual patient effective dose. The SSDE is a good tool for estimating the average radiation dose for a given patient depending on the input parameters and the dimensions of the specific person in question but does not incorporate any organ/tissue weighting factors. It is recommended that when examined patients deviate significantly from the reference person by ICRP, dose should be estimated through the SSDE method. It is also proposed that tissue weighting factors would be incorporated with the SSDE methodology to provide a more refined estimate of risk.
We explore in detail the consequences of the CP-violating phases residing in the supersymmetric a... more We explore in detail the consequences of the CP-violating phases residing in the supersymmetric and soft SUSY breaking parameters in the approximation that family flavour mixings are ignored. We allow for non-universal boundary conditions and in such a consideration the model is described by twelve independent CP-violating phases and one angle which misaligns the vacuum expectation values (VEVs) of the Higgs scalars. We run two-loop renormalization group equations (RGEs), for all parameters involved, including phases, and we properly treat the minimization conditions using the one-loop effective potential with CPviolating phases included. We show that the two-loop running of phases may induce sizable effects for the electric dipole moments (EDMs) that are absent in the one-loop RGE analysis. Also important corrections to the EDMs are induced by the Higgs VEVs misalignment angle which are sizable in the large tan β region. Scanning the available parameter space we seek regions compatible with accelerator and cosmological data with emphasis on rapid neutralino annihilations through a Higgs resonance. It is shown that large CP-violating phases, as required in Baryogenesis scenarios, can be tuned to obtain agreement with WMAP3 cold dark matter constraints, EDMs and all available accelerator data, in extended regions of the parameter space which may be accessible to LHC.
Rhenium-186 (Re-186) is a β-emitting radionuclide. Emitted β-particles have ranges up to 4.5 mm i... more Rhenium-186 (Re-186) is a β-emitting radionuclide. Emitted β-particles have ranges up to 4.5 mm in tissue, capable of delivering high doses to skeletal regions of high Re-186 concentrations while sparing adjacent radiosensitive regions and thus making the irradiation well tolerated for the patient. Along with the β-emissions, γ-rays are emitted having an adequate energy for imaging during therapy and biodistribution assessment for patient-specific dosimetry calculations. The relatively short physical half-life combined with the β-emissions allows the delivery of relatively high activity rate for a short period of time in areas of concentration. This study is a short review concerning the palliative treatment of skeletal metastases using 186Re-HEDP. After presenting the dominant ways of 186Re production, special emphasis is given to dosimetry issues while the effect of palliation therapy can be evaluated through the comparison of the absorbed dose in metastatic lesion relatively to t...
Background: Lung cancer screening (LCS) with annual chest low-dose CT (LDCT) has been recently re... more Background: Lung cancer screening (LCS) with annual chest low-dose CT (LDCT) has been recently recommended for individuals aged 55-80 years at high risk of lung cancer. This study aims at determining the radiation burden and the lifetime attributable risk (LAR) of radiation-induced cancer in individuals undergoing 256-slice LDTC for LCS purposes. Methods: Chest 256-slice LDCT exposures were simulated on mathematical anthropomorphic phantoms of varying body mass index (BMI) using Monte Carlo methods. Normalized and absolute organ doses, as well as effective doses (ED), were estimated. Organ-specific and total cancer LARs were estimated using published age-and sex-specific risk factors. Cumulative LARs from repeated annual LDCT studies were estimated. Total LARs were compared to corresponding nominal lifetime intrinsic risks of cancer (LIRs). Lung cancer LAR was benchmarked against the intrinsic lung cancer risk associated with the screening population. Results: Lung and breast (females) are the organs receiving the highest doses from chest LDCT. Organ-based ED estimates were 0.76mSv and 0.53mSv for females and males of normal BMI, respectively. Absorbed organ doses and ED decrease considerably with BMI. A single chest LDCT exposure at 55 years is associated with 2.0 and 4.8 new cancer incidents per 10 5 average-sized males and females, respectively. The cumulative LAR of radiogenic cancer from repeated annual LDCT studies between the ages of 55 and 80 years was estimated to incur a relative increase in the LIR of being diagnosed with cancer by less than 0.3% and 0.1% in females and males, respectively. For average-sized males and females, repeated annual LDCT exposures lead to 25 and 59, respectively, new lung cancer cases per 10 5 LCS program participants. Discussion: Estimated radiation burden and theoretical radiogenic cancer risks associated with repeated annual 256-slice LDCT chest exposures may alleviate radiation-related concerns regarding the implementation of a LCS program. Provided a modern technology scanner and a carefully considered low-dose protocol are employed, total radiation-induced cancer risk seems to minimally aggravate the lifetime intrinsic cancer risk for the screening population. Furthermore, the radiogenic lung cancer risk constitutes only a minute fraction of the intrinsic high cancer risk associated with such a population.
Biomedical Journal of Scientific & Technical Research, 2019
Monte Carlo [MC] method is a modeling tool, capable of achieving a close adherence to reality, co... more Monte Carlo [MC] method is a modeling tool, capable of achieving a close adherence to reality, concerning the analysis of complex systems. Generally is a method for estimation of the solution of mathematical problems by means of random numbers
We present an improved partial wave analysis of the dominant LSP annihilation channel to a fermio... more We present an improved partial wave analysis of the dominant LSP annihilation channel to a fermion-antifermion pair which avoids the non-relativistic expansion being therefore applicable near thresholds and poles. The method we develop allows of contributions of any partial wave in the total angular momentum J in contrast to partial wave analyses in terms of the orbital angular momentum L of the initial state, which is usually truncated to p-waves, and yields very accurate results. The method is formulated in such a way as to allow easy handling of CP-violating phases residing in supersymmetric parameters. We apply this refined partial wave technique in order to calculate the neutralino relic density in the constrained MSSM (CMSSM) in the presence of CP-violating terms occurring in the Higgs-mixing parameter µ and trilinear A coupling for large tan β. The inclusion of CP-violating phases in µ and A does not upset significantly the picture and the annihilation of the LSP's to a bb, through Higgs exchange, is still the dominant mechanism in obtaining cosmologically acceptable neutralino relic densities in regions far from the stau-coannihilation and the 'focus point'. Significant changes can occur if we allow for phases in the gaugino masses and in particular the gluino mass.
Rhenium-188 (Re-188) is a high energy β-emitting radioisotope obtained from the tungsten-188/rhen... more Rhenium-188 (Re-188) is a high energy β-emitting radioisotope obtained from the tungsten-188/rhenium-188 (W-188/Re-188) generator, which has shown utility for a variety of therapeutic applications in nuclear medicine, oncology, and interventional radiology/cardiology. Re-188 decay is accompanied by a 155 keV predominant energy γ-emission, which could be detected by γ-cameras, for imaging, biodistribution, or absorbed radiation dose studies. Its attractive physical properties and its potential low cost associated with a long-lived parent make it an interesting option for clinical use. The setup and daily use of W-188/Re-188 generator in hospital nuclear medicine departments are discussed in detail. The clinical efficacy, for several therapeutic applications, of a variety of Re-188-labeled agents is demonstrated. The high energy of the β-emission of Re-188 is particularly well suited for effective penetration in solid tumours. Its total radiation dose delivered to tissues is comparabl...
We explore in detail the consequences of the CP-violating phases residing in the supersymmetric a... more We explore in detail the consequences of the CP-violating phases residing in the supersymmetric and soft SUSY breaking parameters in the approximation that family flavour mixings are ignored. We allow for non-universal boundary conditions and in such a consideration the model is described by twelve independent CP-violating phases and one angle which misaligns the vacuum expectation values (VEVs) of the Higgs scalars. We run two-loop renormalization group equations (RGEs), for all parameters involved, including phases, and we properly treat the minimization conditions using the one-loop effective potential with CPviolating phases included. We show that the two-loop running of phases may induce sizable effects for the electric dipole moments (EDMs) that are absent in the one-loop RGE analysis. Also important corrections to the EDMs are induced by the Higgs VEVs misalignment angle which are sizable in the large tanβ region. Scanning the available parameter space we seek regions compati...
The aim of this work consists of modeling the left ventricle of the heart, at stress and rest sit... more The aim of this work consists of modeling the left ventricle of the heart, at stress and rest situation, using the myocardial scintigraphic data obtained in 3D stress/rest images and focuses on the possibility of quantification of differences. 32 cardiac patients completed stress and rest tests by Tc99m tetrofosmin in one-day protocol by a GE-Starcam-4000 gammacamera; Images of myocardium were reconstructed by the GE Volumetrix software in the GE Xeleris processing system. Myocardial perfusion was estimated by all (Short axis, HLA (Horizontal Long Axis) and VLA (Vertical Long Axis)) SPECT slices. For each patient, 2 series of transverse slices by tomographic image reconstruction, were produced, using OSEM iterative algorithm. DICOM data was extracted for each patient and an algorithm that integrates 3D visualization has been used for image processing analysis by MatLabR2012b. The appropriate threshold value was identified by creating intensity isocontours. The myocardium volume was evaluated and reconstructed as 3D image and calculations of the differences between the rest and stress data of the 3D images were made. An index ratio of the Volume of Interest (VOI) was determined. The differences between 3D images at rest and stress situations provide us with visual and quantitative evaluation of myocardial perfusion.
The aim of this study is to examine the impact of dark signal on assessing the image quality in c... more The aim of this study is to examine the impact of dark signal on assessing the image quality in computerized mammography. A GE analogue mammography unit was calibrated to be used with an Agfa CR35-X system. Tests for quality control were performed and Image Plates (IPs) were erased by the CR system. All IPs were first exposed to known amounts of scatter radiation and then used to take mammographic images of phantoms with varying density (a PASMAM-1054 Phantom with PMMA and Al inserts). Since high Signal-to-noise ratio (SNR) and high Contrast-to-noise ratio (CNR) are of great importance in mammographic image quality, we measured SNR and CNR of the taken images. Our results show the effect of scatter radiation on SNR and CNR. Scatter radiation increases SNR and decreases CNR. The impact of background signal was found not to be negligible. Dark signal deteriorates image quality in CR mammography. Consequently, further investigation may be warranted and daily erasure of the IPs is recom...
Rhenium-188 (Re-188) is a high energy β-emitting radioisotope obtained from the tungsten-188/rhen... more Rhenium-188 (Re-188) is a high energy β-emitting radioisotope obtained from the tungsten-188/rhenium-188 (W-188/Re-188) generator, which has shown utility for a variety of therapeutic applications in nuclear medicine, oncology, and interventional radiology/cardiology. Re-188 decay is accompanied by a 155 keV predominant energy γ-emission, which could be detected by γ-cameras, for imaging, biodistribution, or absorbed radiation dose studies. Its attractive physical properties and its potential low cost associated with a long-lived parent make it an interesting option for clinical use. The setup and daily use of W-188/Re-188 generator in hospital nuclear medicine departments are discussed in detail. The clinical efficacy, for several therapeutic applications, of a variety of Re-188-labeled agents is demonstrated. The high energy of the β-emission of Re-188 is particularly well suited for effective penetration in solid tumours. Its total radiation dose delivered to tissues is comparabl...
Purpose: The aim of this work consists of a method of determination of the thyroid gland's volume... more Purpose: The aim of this work consists of a method of determination of the thyroid gland's volume using the SPECT data in order to calculate the absorbed patient dose from the radioactive substances injected to the patient during thyroid treatment.
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Papers by Maria Argyrou