Purpose Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modeling many phys... more Purpose Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modeling many physical phenomena which are difficult to track or measure directly. MC simulation in SPECT/CT imaging is particularly suitable for optimizing the quantification of activity in a patient, and, consequently, the absorbed dose to each organ. To do so, validating MC results with real data acquired with gamma camera is mandatory. The aim of this study was the validation of the calibration factor (CF) and the recovery coefficient (RC) obtained with SIMIND Monte Carlo code for modeling a Siemens Symbia Intevo Excel SPECT-CT gamma camera to ensure optimal $$^{99m}$$ 99 m Tc and $$^{177}$$ 177 Lu SPECT quantification. Methods Phantom experiments using $$^{99m}$$ 99 m Tc and $$^{177}$$ 177 Lu have been performed to measure spatial resolution and sensitivity, as well as to evaluate the CF and RC from acquired data. The geometries used for 2D planar imaging were (1) Petri dish and (2) capillary source ...
Purpose : Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modelling many p... more Purpose : Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modelling many physical phenomena which are difficult to track or to measure directly. MC simulation in SPECT/CT imaging is particularly suitable for optimizing the quantification of activity in a patient, and, consequently, the absorbed dose to each organ. To do so, it is mandatory validate MC results with real data acquired with gamma camera. The aim of this study was the validation of SIMIND Monte Carlo code for modelling a Siemens Symbia Intevo Excel SPECT-CT gamma camera both for 99m Tc and 177 Lu. Methods : Phantom experiments using 99m Tc and 177 Lu have been performed with the purpose to measure spatial resolution, sensitivity and evaluate the calibration factor (CF) and recovery coefficients (RC) from acquired data. The geometries used for 2D planar imaging were (1) Petri dish and (2) capillary source while for 3D volumetric imaging were (3) a uniform filled cylinder phantom and (4) a Jaszczack...
1993 IEEE International Solid-State Circuits Conference Digest of Technical Papers, 1993
Abstract The authors introduce a bandpass architecture and implementation that achieves 15-b dyna... more Abstract The authors introduce a bandpass architecture and implementation that achieves 15-b dynamic range over a 30-kHz bandwidth centered at 1.8 MHz using 7.2-MHz sampling frequency and operating on a single 5-V supply. A z-domain representation of the fourth-...
Microdosimetry and track-nanodosimetry belong to a recent branch of nuclear physics, which concer... more Microdosimetry and track-nanodosimetry belong to a recent branch of nuclear physics, which concerns the study of theoretical and experimental methodologies able to perform a detailed analysis of the radiation interaction with matter, in particular with biological tissue at cellular and sub-cellular level. In radiotherapy the treatment planning aims to deliver sufficient radiation to the tumour while sparing critical organs and minimizing the doze to healthy tissue. To date, the Tissue Equivalent Proportional Counter (TEPC) is the most accurate device able to measure the microdosimetric properties of ionizing processes, and it has showed to properly mimic the corresponding relative biological effectiveness (RBE). Since the track structure plays a significant role at the nanometer level, the microdosimetric approach is not able to provide detailed information about that: common TEPCs are able to measure single event spectra in sites down to about 300 nm. The nanodosimetric quantities ...
During the last decade, a major improvement in the field of the Micro-Pattern Gaseous Detectors h... more During the last decade, a major improvement in the field of the Micro-Pattern Gaseous Detectors has been reached by adding a layer of resistive strips above the readout strips to reduce drastically the effect of discharges. The resistive strips are separated from the readout strips by a thin layer of insulator. When the detector is operated some gain reduction is observed over the first seconds or minutes after switch-on, stabilising after some time. Is this related to the presence of the insulator or are there other mechanisms at work? We report here the results of a detailed study of this effect and compare resistive-strip and Diamond Like Carbon (DLC) Micromegas detectors. We will present and quantify the main characteristics of this effect, i.e, the relative gain drop and the time to reach a stable regime, as a function of the detector configuration and rate. In addition we studied the influence of the pillars that support the mesh on the behaviour of bulk and non-bulk Micromega...
Purpose Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modeling many phys... more Purpose Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modeling many physical phenomena which are difficult to track or measure directly. MC simulation in SPECT/CT imaging is particularly suitable for optimizing the quantification of activity in a patient, and, consequently, the absorbed dose to each organ. To do so, validating MC results with real data acquired with gamma camera is mandatory. The aim of this study was the validation of the calibration factor (CF) and the recovery coefficient (RC) obtained with SIMIND Monte Carlo code for modeling a Siemens Symbia Intevo Excel SPECT-CT gamma camera to ensure optimal $$^{99m}$$ 99 m Tc and $$^{177}$$ 177 Lu SPECT quantification. Methods Phantom experiments using $$^{99m}$$ 99 m Tc and $$^{177}$$ 177 Lu have been performed to measure spatial resolution and sensitivity, as well as to evaluate the CF and RC from acquired data. The geometries used for 2D planar imaging were (1) Petri dish and (2) capillary source ...
Purpose : Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modelling many p... more Purpose : Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modelling many physical phenomena which are difficult to track or to measure directly. MC simulation in SPECT/CT imaging is particularly suitable for optimizing the quantification of activity in a patient, and, consequently, the absorbed dose to each organ. To do so, it is mandatory validate MC results with real data acquired with gamma camera. The aim of this study was the validation of SIMIND Monte Carlo code for modelling a Siemens Symbia Intevo Excel SPECT-CT gamma camera both for 99m Tc and 177 Lu. Methods : Phantom experiments using 99m Tc and 177 Lu have been performed with the purpose to measure spatial resolution, sensitivity and evaluate the calibration factor (CF) and recovery coefficients (RC) from acquired data. The geometries used for 2D planar imaging were (1) Petri dish and (2) capillary source while for 3D volumetric imaging were (3) a uniform filled cylinder phantom and (4) a Jaszczack...
1993 IEEE International Solid-State Circuits Conference Digest of Technical Papers, 1993
Abstract The authors introduce a bandpass architecture and implementation that achieves 15-b dyna... more Abstract The authors introduce a bandpass architecture and implementation that achieves 15-b dynamic range over a 30-kHz bandwidth centered at 1.8 MHz using 7.2-MHz sampling frequency and operating on a single 5-V supply. A z-domain representation of the fourth-...
Microdosimetry and track-nanodosimetry belong to a recent branch of nuclear physics, which concer... more Microdosimetry and track-nanodosimetry belong to a recent branch of nuclear physics, which concerns the study of theoretical and experimental methodologies able to perform a detailed analysis of the radiation interaction with matter, in particular with biological tissue at cellular and sub-cellular level. In radiotherapy the treatment planning aims to deliver sufficient radiation to the tumour while sparing critical organs and minimizing the doze to healthy tissue. To date, the Tissue Equivalent Proportional Counter (TEPC) is the most accurate device able to measure the microdosimetric properties of ionizing processes, and it has showed to properly mimic the corresponding relative biological effectiveness (RBE). Since the track structure plays a significant role at the nanometer level, the microdosimetric approach is not able to provide detailed information about that: common TEPCs are able to measure single event spectra in sites down to about 300 nm. The nanodosimetric quantities ...
During the last decade, a major improvement in the field of the Micro-Pattern Gaseous Detectors h... more During the last decade, a major improvement in the field of the Micro-Pattern Gaseous Detectors has been reached by adding a layer of resistive strips above the readout strips to reduce drastically the effect of discharges. The resistive strips are separated from the readout strips by a thin layer of insulator. When the detector is operated some gain reduction is observed over the first seconds or minutes after switch-on, stabilising after some time. Is this related to the presence of the insulator or are there other mechanisms at work? We report here the results of a detailed study of this effect and compare resistive-strip and Diamond Like Carbon (DLC) Micromegas detectors. We will present and quantify the main characteristics of this effect, i.e, the relative gain drop and the time to reach a stable regime, as a function of the detector configuration and rate. In addition we studied the influence of the pillars that support the mesh on the behaviour of bulk and non-bulk Micromega...
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