Giorgia Iurlaro - Academia.edu (original) (raw)
Papers by Giorgia Iurlaro
Revisione del D.Lgs. 52/2007 e sue applicazioni all'interno dei laboratori ENEA. Si considera... more Revisione del D.Lgs. 52/2007 e sue applicazioni all'interno dei laboratori ENEA. Si considera il sistema complesso ENEA "detentore" di sorgenti di radiazioni e "richiedente" di autorizzazioni.
Clinical Oral Implants Research, 2009
Aim: To evaluate the soft tissue response to immediately placed implants using the platform switc... more Aim: To evaluate the soft tissue response to immediately placed implants using the platform switching concept.
The International journal of prosthodontics
The aim of this study was to evaluate the short-term bone level response around immediately place... more The aim of this study was to evaluate the short-term bone level response around immediately placed and provisionally restored implants using a platform switching concept. Twenty-two implants with a platform diameter of 5.5 mm were immediately placed in healthy maxillary sites in 22 patients. Resultant circumimplant spaces were filled with a mixture of bovine bone matrix and collagen. The implants were randomly divided into two equal groups: 11 implants connected with 3.8-mm-diameter abutments (test group) and 11 with 5.5-mm-diameter ones (control). Provisional crowns were adapted and adjusted for nonfunctional immediate placement on each implant and the final crowns were constructed 2 months later. Posttreatment assessments were carried out by an independent trained observer at the time of implant placement (baseline), at definitive prosthesis insertion, and every 6 months thereafter. These assessments included periapical radiographs, pocket probing depths (PPD), bleeding on probing (BOP), and modified Plaque Index (mPII) on both implants and first proximal teeth. An image analysis software application was used to compare the bone crestal heights at the mesial and distal aspects of the implants. The mean follow-up observation period was 25 months and all implants were judged to be successfully osseointegrated. In the test group, radiographic analysis showed an average bone reduction level of 0.30 mm (SD = 0.16 mm). This mean value was statistically significantly different (P < or = .005) from the average reduction in the control group (mean = 1.19 mm, SD = 0.35 mm). No differences between the two groups in PPD, BOP, or mPII were found. This preliminary study suggests that immediate single implant restorations in specific maxillary sites with subsequent platform switching may provide peri-implant alveolar bone-level stability.
SOMMARIO – Pazienti diabetici sono spesso affetti da una complessa sindrome che va sotto il nome ... more SOMMARIO – Pazienti diabetici sono spesso affetti da una complessa sindrome che va sotto il nome di piede diabetico. Le infezioni sono la causa maggiore di menomazioni in questi pazienti e l’estensione dell’infezione all’osso è la causa più comune dell’amputazione delle estremità inferiori e spesso di mortalità. Lo studio ai raggi X si mostra spesso di inadeguata accuratezza per una diagnosi precoce dell’osteomielite del piede. La biopsia dell’osso è utile per determinare l'osteomielite e fornisce informazioni batteriologiche; ma è invasiva e potenzialmente nociva. La scintigrafia con leucociti marcati 99mTc-HMPAO è in grado di mostrare la flogosi ma può mancare l'individuazione di una precoce estensione all’osso perché la risoluzione spaziale dell’Anger Camera (AG) non è sempre in grado di distinguere l’infezione del tessuto soffice dal coinvolgimento dell’osso. Inoltre la chirurgia radioguidata con sonde convenzionali non fornisce immagini non permettendo di distinguere la ...
In seguito all’incidente nucleare di Fukushima in Giappone, presso il Laboratorio di Sorveglianza... more In seguito all’incidente nucleare di Fukushima in Giappone, presso il Laboratorio di Sorveglianza Ambientale del C.R. ENEA Casaccia sono state intensificate le misure radiometriche ambientali allo scopo di monitorare l’andamento dell’eventuale presenza di radioattività in aria riconducibile al fall out dell’incidente. E’ stata attivato un controllo giornaliero e settimanale del particolato in aria per verificare la presenza di radioisotopi come iodio e cesio. Sono state campionate matrici alimentari particolarmente significative, come latte crudo e vegetali a foglia larga, ed è stato messo in funzione un sistema in grado di separare durante il campionamento i due contributi secco e umido della deposizione al suolo. Presso il Laboratorio di Sorveglianza Ambientale è stato sperimentato un piano di misure in grado di fornire una risposta rapida in possibili situazioni di emergenze radiologiche che potrebbero portare la diffusione di sostanze radioattive nell’ambiente anche sul territor...
Nella determinazione dell’attività di emettitori gamma con rivelatori al germanio iperpuro (HPGe)... more Nella determinazione dell’attività di emettitori gamma con rivelatori al germanio iperpuro (HPGe) si impiegano sorgenti di calibrazione che possono avere densità differenti rispetto alle matrici ambientali realmente misurate come ortaggi e terreno. Lo studio eseguito presso il Laboratorio di Sorveglianza Fisica e Ambientale del C.R. ENEA Casaccia si basa sulla sperimentazione delle correzioni delle curve di efficienza per rivelatori X-Gamma HPGe, cercando di evidenziare la sensibilità del rivelatore alle basse energie. Le variazioni nelle curve di efficienza sono essenzialmente dovute ad effetti di autoassorbimento della matrice analizzata, partendo da dati sperimentali acquisiti con matrici di riferimento saranno calcolati i coefficienti di auto assorbimento. Partendo dalla caratterizzazione del rivelatore (forma del cristallo e posizione), attraverso le specifiche fornite dal costruttore, le informazioni ottenute saranno impiegate per calcolare numericamente i fattori correttivi d...
La spettrometria gamma in situ è una tecnica frequentemente impiegata per determinare i livelli d... more La spettrometria gamma in situ è una tecnica frequentemente impiegata per determinare i livelli di deposizione di radioattività al suolo. E’stata introdotta nei sistemi di monitoraggio ambientale per determinare il rateo di dose gamma outdoor e per calcolare la concentrazione dei radionuclidi e il relativo contributo al rateo di dose [1,2]. Presso i laboratori BAS ION IRP di Sorveglianza Ambientale del C.R. Casaccia si eseguono analisi di routine dei campioni di terreno attraverso misure di spettrometria gamma e spettrometria alfa degli isotopi del Plutonio. Allo scopo di integrare tali metodiche è stato avviato uno studio di fattibilità dell’applicazione della misura spettrometrica in situ eseguita con rivelatore a germanio iperpuro (HPGe). L’obiettivo finale del lavoro consiste essenzialmente nell’acquisire le conoscenze di base della tecnica di misura, valutandone i vantaggi e i limiti nell’applicazione.
L’Istituto di Radioprotezione ENEA (IRP) assicura la sorveglianza fisica di radioprotezione per t... more L’Istituto di Radioprotezione ENEA (IRP) assicura la sorveglianza fisica di radioprotezione per tutte le attività con rischi da radiazioni ionizzanti all’interno dei centri di ricerca ENEA, con lo scopo principale di tutelare la salute dei lavoratori, della popolazione e dell’ambiente. Per garantire il migliore servizio nell’affrontare tutte le problematiche connesse alla misura della radioattività è stato creato, nell’ambito del Coordinamento “Attività di Valutazioni e Sorveglianza di Radioprotezione”, un gruppo di lavoro tra gli Esperti Qualificati ENEA per la stesura di una serie di procedure a supporto delle attività di sorveglianza fisica della radioprotezione di responsabilità dell’EQ. Le procedure prevedono la descrizione delle singole tecniche e metodologie di misura, fanno riferimento a documenti internazionali aggiornati e referenziabili e applicano le norme tecniche nazionali ed internazionali in vigore, facendo tesoro dell’esperienza dei centri ENEA, maturata nel corso d...
The International journal of prosthodontics
The aim of this study was to evaluate the short-term bone level response around immediately place... more The aim of this study was to evaluate the short-term bone level response around immediately placed and provisionally restored implants using a platform switching concept. Twenty-two implants with a platform diameter of 5.5 mm were immediately placed in healthy maxillary sites in 22 patients. Resultant circumimplant spaces were filled with a mixture of bovine bone matrix and collagen. The implants were randomly divided into two equal groups: 11 implants connected with 3.8-mm-diameter abutments (test group) and 11 with 5.5-mm-diameter ones (control). Provisional crowns were adapted and adjusted for nonfunctional immediate placement on each implant and the final crowns were constructed 2 months later. Posttreatment assessments were carried out by an independent trained observer at the time of implant placement (baseline), at definitive prosthesis insertion, and every 6 months thereafter. These assessments included periapical radiographs, pocket probing depths (PPD), bleeding on probing...
The aim of this work was to evaluate the suitability of Si avalanche photodiodes for low-energy s... more The aim of this work was to evaluate the suitability of Si avalanche photodiodes for low-energy scintillation readout in single-photon modality. The energy of interest for low-energy nuclear medicine applications is in the range from 100 keV to 200 keV. We studied experimental assemblies based on a small parallelepiped CsI(Tl) scintillation crystal coupled to different single-photosensors. A model describing the scintillation light distribution emerging from the crystal was used to choose the photodiode models and to foresee the assembly responses. Some Hamamatsu S8664-series photodiodes were selected for this preliminary study, with the aim of future applications involving S8550 arrays made by the same manufacturer. Pulse height and energy resolution have been mainly studied.
Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications - Proceedings of the 9th Conference, 2006
The limiting factors for the scintigraphic clinical application are related to i) biosource chara... more The limiting factors for the scintigraphic clinical application are related to i) biosource characteristics (pharmacokinetic of the drug distribution between organs), Detection chain (photons transport, scintillation, analog to digital signal conversion, etc.) Imaging (Signal to Noise ratio, Spatial and Energy Resolution, Linearity etc) In this work, by using Monte Carlo time resolved transport simulations on a mathematical phantom and on a small field of view scintigraphic device, the trade off between the aforementioned factors was preliminary investigated.
2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515), 2003
The present development of new gamma imagers has allowed to realize detectors with ultra high spa... more The present development of new gamma imagers has allowed to realize detectors with ultra high spatial resolution and very compact size for PET as well as for SPET application.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007
In this work we report and compare the results of gamma-ray spectroscopy measurements performed u... more In this work we report and compare the results of gamma-ray spectroscopy measurements performed using a LaBr 3 :Ce crystal coupled to a photomultiplier tube with modified base and to a Si-avalanche photodiode readout by standard electronics. Energy resolution values have been obtained in the range from 59.5keV ( 241 Am) to 1332keV ( 60 Co). Good linearity in energy response has been found. Energy resolution values obtained with avalanche photodiode readout are underestimated due to the small active area of the presently available photosensor with respect to crystal dimension.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2007
Irradiation resistance of as-studied scintillating glass samples were tested under the 60 Co c-ra... more Irradiation resistance of as-studied scintillating glass samples were tested under the 60 Co c-ray radiation at doses between 60 and 700 Gy. Photoluminescence properties of glasses with and without cerium ions were investigated to show the effect of cerium (III) on the luminescence of ZnO. Ultraviolet and visible optical transmittance spectra were compared before and after irradiation treatment. The so-called radiation-induced absorption coefficient (RIAC) was introduced to compare more effectively the radiation damage on glass samples. The much reduced transmittance change and decreased RIAC value in UV-Vis region indicate that the density of electron centers and hole centers caused by radiation decreased, which helps to confirm that the reduction and oxidation reaction of cerium ions took place in radiation process. From RIAC curves, it can be seen that TiO 2 enhances the irradiation resistance of sample in UV region. However, high TiO 2 content has negative effect on visible transmittance of glasses after the higher dose irradiation (700 Gy).
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2005
This work presents the results obtained with a new generation portable gamma camera, assembled wi... more This work presents the results obtained with a new generation portable gamma camera, assembled with an innovative technique based on CsI(Tl) scintillation crystals inserted into the square holes of a tungsten collimator. Characterization measurements have been performed on three detectors with different crystal size, in order to obtain 7 Â 7, 8 Â 8 and 9 Â 9 arrays over the fixed area of 25.7 Â 25.7 mm 2 , having the same overall dimensions of a Position Sensitive Photomultiplier Tube. Detector sensitivity, energy resolution and spatial resolution have been measured, and the acquired image quality has been evaluated with particular attention to pixel identification capability. r
Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications - Proceedings of the 9th Conference, 2006
In principle, a scintillation imager made by a crystal array and a position-sensitive photomultip... more In principle, a scintillation imager made by a crystal array and a position-sensitive photomultiplier shows spatial non linearities at borders due to the undersampling of scintillation light distributions. To improve the response of such detectors a method has been carried out based on the comparison between experimental and simulated images. A computer simulation code has been developed and used to foresee the imager response. The code computes the tapered charge-weighting factors giving the optimized event centroiding in terms of crystal-pixel identification. The comparison between measured centroids and crystal axes produces the effective correction table for image linearization. Experimental results concerning a 8x8 crystal array coupled to a position sensitive photomultiplier tube (1 inch square) are presented and discussed.
Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications - Proceedings of the 9th Conference, 2006
The feasibility of a subminiature scintillation detector to be inserted in a catheter for lesion ... more The feasibility of a subminiature scintillation detector to be inserted in a catheter for lesion localization in nuclear medicine SPECT has been studied. Measurements on a simple laboratory setup have been performed and compared with Monte Carlo results. Further simulations, at 30keV and 140keV, concerning a configuration reproducing severe clinical conditions have shown poor lesion detectability. Several factors affecting the response have to be investigated to improve the capability of lesion localization characterizing such detector.
Sensors and Microsystems - Proceedings of the 10th Italian Conference, 2008
This work is aimed to study the feasibility of a low energy gamma-ray detector for nuclear medici... more This work is aimed to study the feasibility of a low energy gamma-ray detector for nuclear medicine to be inserted into a body cavity, duct, or vessel. The small dimension detector concept is based on a CsI:Tl scintillation crystal coupled to a Si Avalanche Photodiode (APD) mounted in a catheter. Due to the availability of 99m Tc in nuclear medicine departments, 140 keV photons have been considered for detector design. At this energy the response concerns a more extended volume nearby the cathector than in the case of beta emitting radiotracers. Monte Carlo simulations have been performed and results have then been compared to experimental ones. The latter have been obtained using a 57 Co radioisotopic source and a laboratory setup including a detector having dimensions not optimized coupled to a low-noise conventional electronics. Count rates and sensitivities have been measured approaching a point source to the detector along some paths and considering different background irradiation levels.
IEEE Symposium Conference Record Nuclear Science 2004., 2004
A computer simulation code has been developed in order to foresee the response of discrete scinti... more A computer simulation code has been developed in order to foresee the response of discrete scintillation imaging devices. DIscrete Scintillation Imager Simulator (DISIS) has been designed for imagers based on a scintillation array coupled to a position sensitive light sensor (like position sensitive photomultiplier tube or avalanche photodiode array) by a planar light guide. The simulator is a deterministic code that uses: (i) a model describing the single photon light distribution emerging from a crystal pixel for charge integrals evaluation; (ii) the assigned algorithm for centroid calculation and; (iii) the Gaussian spread for localizing, crystal by crystal, the events on the image. In particular DISIS allows us to study the spatial response over the imager field of view changing parameters individually. The imager optimization can be obtained searching an acceptable pixel identification. To this aim a good trade-off between the spread of light distribution, the light sampling capability over the lightsensor area and the centroiding algorithm has to be found.
Revisione del D.Lgs. 52/2007 e sue applicazioni all'interno dei laboratori ENEA. Si considera... more Revisione del D.Lgs. 52/2007 e sue applicazioni all'interno dei laboratori ENEA. Si considera il sistema complesso ENEA "detentore" di sorgenti di radiazioni e "richiedente" di autorizzazioni.
Clinical Oral Implants Research, 2009
Aim: To evaluate the soft tissue response to immediately placed implants using the platform switc... more Aim: To evaluate the soft tissue response to immediately placed implants using the platform switching concept.
The International journal of prosthodontics
The aim of this study was to evaluate the short-term bone level response around immediately place... more The aim of this study was to evaluate the short-term bone level response around immediately placed and provisionally restored implants using a platform switching concept. Twenty-two implants with a platform diameter of 5.5 mm were immediately placed in healthy maxillary sites in 22 patients. Resultant circumimplant spaces were filled with a mixture of bovine bone matrix and collagen. The implants were randomly divided into two equal groups: 11 implants connected with 3.8-mm-diameter abutments (test group) and 11 with 5.5-mm-diameter ones (control). Provisional crowns were adapted and adjusted for nonfunctional immediate placement on each implant and the final crowns were constructed 2 months later. Posttreatment assessments were carried out by an independent trained observer at the time of implant placement (baseline), at definitive prosthesis insertion, and every 6 months thereafter. These assessments included periapical radiographs, pocket probing depths (PPD), bleeding on probing (BOP), and modified Plaque Index (mPII) on both implants and first proximal teeth. An image analysis software application was used to compare the bone crestal heights at the mesial and distal aspects of the implants. The mean follow-up observation period was 25 months and all implants were judged to be successfully osseointegrated. In the test group, radiographic analysis showed an average bone reduction level of 0.30 mm (SD = 0.16 mm). This mean value was statistically significantly different (P < or = .005) from the average reduction in the control group (mean = 1.19 mm, SD = 0.35 mm). No differences between the two groups in PPD, BOP, or mPII were found. This preliminary study suggests that immediate single implant restorations in specific maxillary sites with subsequent platform switching may provide peri-implant alveolar bone-level stability.
SOMMARIO – Pazienti diabetici sono spesso affetti da una complessa sindrome che va sotto il nome ... more SOMMARIO – Pazienti diabetici sono spesso affetti da una complessa sindrome che va sotto il nome di piede diabetico. Le infezioni sono la causa maggiore di menomazioni in questi pazienti e l’estensione dell’infezione all’osso è la causa più comune dell’amputazione delle estremità inferiori e spesso di mortalità. Lo studio ai raggi X si mostra spesso di inadeguata accuratezza per una diagnosi precoce dell’osteomielite del piede. La biopsia dell’osso è utile per determinare l'osteomielite e fornisce informazioni batteriologiche; ma è invasiva e potenzialmente nociva. La scintigrafia con leucociti marcati 99mTc-HMPAO è in grado di mostrare la flogosi ma può mancare l'individuazione di una precoce estensione all’osso perché la risoluzione spaziale dell’Anger Camera (AG) non è sempre in grado di distinguere l’infezione del tessuto soffice dal coinvolgimento dell’osso. Inoltre la chirurgia radioguidata con sonde convenzionali non fornisce immagini non permettendo di distinguere la ...
In seguito all’incidente nucleare di Fukushima in Giappone, presso il Laboratorio di Sorveglianza... more In seguito all’incidente nucleare di Fukushima in Giappone, presso il Laboratorio di Sorveglianza Ambientale del C.R. ENEA Casaccia sono state intensificate le misure radiometriche ambientali allo scopo di monitorare l’andamento dell’eventuale presenza di radioattività in aria riconducibile al fall out dell’incidente. E’ stata attivato un controllo giornaliero e settimanale del particolato in aria per verificare la presenza di radioisotopi come iodio e cesio. Sono state campionate matrici alimentari particolarmente significative, come latte crudo e vegetali a foglia larga, ed è stato messo in funzione un sistema in grado di separare durante il campionamento i due contributi secco e umido della deposizione al suolo. Presso il Laboratorio di Sorveglianza Ambientale è stato sperimentato un piano di misure in grado di fornire una risposta rapida in possibili situazioni di emergenze radiologiche che potrebbero portare la diffusione di sostanze radioattive nell’ambiente anche sul territor...
Nella determinazione dell’attività di emettitori gamma con rivelatori al germanio iperpuro (HPGe)... more Nella determinazione dell’attività di emettitori gamma con rivelatori al germanio iperpuro (HPGe) si impiegano sorgenti di calibrazione che possono avere densità differenti rispetto alle matrici ambientali realmente misurate come ortaggi e terreno. Lo studio eseguito presso il Laboratorio di Sorveglianza Fisica e Ambientale del C.R. ENEA Casaccia si basa sulla sperimentazione delle correzioni delle curve di efficienza per rivelatori X-Gamma HPGe, cercando di evidenziare la sensibilità del rivelatore alle basse energie. Le variazioni nelle curve di efficienza sono essenzialmente dovute ad effetti di autoassorbimento della matrice analizzata, partendo da dati sperimentali acquisiti con matrici di riferimento saranno calcolati i coefficienti di auto assorbimento. Partendo dalla caratterizzazione del rivelatore (forma del cristallo e posizione), attraverso le specifiche fornite dal costruttore, le informazioni ottenute saranno impiegate per calcolare numericamente i fattori correttivi d...
La spettrometria gamma in situ è una tecnica frequentemente impiegata per determinare i livelli d... more La spettrometria gamma in situ è una tecnica frequentemente impiegata per determinare i livelli di deposizione di radioattività al suolo. E’stata introdotta nei sistemi di monitoraggio ambientale per determinare il rateo di dose gamma outdoor e per calcolare la concentrazione dei radionuclidi e il relativo contributo al rateo di dose [1,2]. Presso i laboratori BAS ION IRP di Sorveglianza Ambientale del C.R. Casaccia si eseguono analisi di routine dei campioni di terreno attraverso misure di spettrometria gamma e spettrometria alfa degli isotopi del Plutonio. Allo scopo di integrare tali metodiche è stato avviato uno studio di fattibilità dell’applicazione della misura spettrometrica in situ eseguita con rivelatore a germanio iperpuro (HPGe). L’obiettivo finale del lavoro consiste essenzialmente nell’acquisire le conoscenze di base della tecnica di misura, valutandone i vantaggi e i limiti nell’applicazione.
L’Istituto di Radioprotezione ENEA (IRP) assicura la sorveglianza fisica di radioprotezione per t... more L’Istituto di Radioprotezione ENEA (IRP) assicura la sorveglianza fisica di radioprotezione per tutte le attività con rischi da radiazioni ionizzanti all’interno dei centri di ricerca ENEA, con lo scopo principale di tutelare la salute dei lavoratori, della popolazione e dell’ambiente. Per garantire il migliore servizio nell’affrontare tutte le problematiche connesse alla misura della radioattività è stato creato, nell’ambito del Coordinamento “Attività di Valutazioni e Sorveglianza di Radioprotezione”, un gruppo di lavoro tra gli Esperti Qualificati ENEA per la stesura di una serie di procedure a supporto delle attività di sorveglianza fisica della radioprotezione di responsabilità dell’EQ. Le procedure prevedono la descrizione delle singole tecniche e metodologie di misura, fanno riferimento a documenti internazionali aggiornati e referenziabili e applicano le norme tecniche nazionali ed internazionali in vigore, facendo tesoro dell’esperienza dei centri ENEA, maturata nel corso d...
The International journal of prosthodontics
The aim of this study was to evaluate the short-term bone level response around immediately place... more The aim of this study was to evaluate the short-term bone level response around immediately placed and provisionally restored implants using a platform switching concept. Twenty-two implants with a platform diameter of 5.5 mm were immediately placed in healthy maxillary sites in 22 patients. Resultant circumimplant spaces were filled with a mixture of bovine bone matrix and collagen. The implants were randomly divided into two equal groups: 11 implants connected with 3.8-mm-diameter abutments (test group) and 11 with 5.5-mm-diameter ones (control). Provisional crowns were adapted and adjusted for nonfunctional immediate placement on each implant and the final crowns were constructed 2 months later. Posttreatment assessments were carried out by an independent trained observer at the time of implant placement (baseline), at definitive prosthesis insertion, and every 6 months thereafter. These assessments included periapical radiographs, pocket probing depths (PPD), bleeding on probing...
The aim of this work was to evaluate the suitability of Si avalanche photodiodes for low-energy s... more The aim of this work was to evaluate the suitability of Si avalanche photodiodes for low-energy scintillation readout in single-photon modality. The energy of interest for low-energy nuclear medicine applications is in the range from 100 keV to 200 keV. We studied experimental assemblies based on a small parallelepiped CsI(Tl) scintillation crystal coupled to different single-photosensors. A model describing the scintillation light distribution emerging from the crystal was used to choose the photodiode models and to foresee the assembly responses. Some Hamamatsu S8664-series photodiodes were selected for this preliminary study, with the aim of future applications involving S8550 arrays made by the same manufacturer. Pulse height and energy resolution have been mainly studied.
Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications - Proceedings of the 9th Conference, 2006
The limiting factors for the scintigraphic clinical application are related to i) biosource chara... more The limiting factors for the scintigraphic clinical application are related to i) biosource characteristics (pharmacokinetic of the drug distribution between organs), Detection chain (photons transport, scintillation, analog to digital signal conversion, etc.) Imaging (Signal to Noise ratio, Spatial and Energy Resolution, Linearity etc) In this work, by using Monte Carlo time resolved transport simulations on a mathematical phantom and on a small field of view scintigraphic device, the trade off between the aforementioned factors was preliminary investigated.
2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515), 2003
The present development of new gamma imagers has allowed to realize detectors with ultra high spa... more The present development of new gamma imagers has allowed to realize detectors with ultra high spatial resolution and very compact size for PET as well as for SPET application.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007
In this work we report and compare the results of gamma-ray spectroscopy measurements performed u... more In this work we report and compare the results of gamma-ray spectroscopy measurements performed using a LaBr 3 :Ce crystal coupled to a photomultiplier tube with modified base and to a Si-avalanche photodiode readout by standard electronics. Energy resolution values have been obtained in the range from 59.5keV ( 241 Am) to 1332keV ( 60 Co). Good linearity in energy response has been found. Energy resolution values obtained with avalanche photodiode readout are underestimated due to the small active area of the presently available photosensor with respect to crystal dimension.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2007
Irradiation resistance of as-studied scintillating glass samples were tested under the 60 Co c-ra... more Irradiation resistance of as-studied scintillating glass samples were tested under the 60 Co c-ray radiation at doses between 60 and 700 Gy. Photoluminescence properties of glasses with and without cerium ions were investigated to show the effect of cerium (III) on the luminescence of ZnO. Ultraviolet and visible optical transmittance spectra were compared before and after irradiation treatment. The so-called radiation-induced absorption coefficient (RIAC) was introduced to compare more effectively the radiation damage on glass samples. The much reduced transmittance change and decreased RIAC value in UV-Vis region indicate that the density of electron centers and hole centers caused by radiation decreased, which helps to confirm that the reduction and oxidation reaction of cerium ions took place in radiation process. From RIAC curves, it can be seen that TiO 2 enhances the irradiation resistance of sample in UV region. However, high TiO 2 content has negative effect on visible transmittance of glasses after the higher dose irradiation (700 Gy).
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2005
This work presents the results obtained with a new generation portable gamma camera, assembled wi... more This work presents the results obtained with a new generation portable gamma camera, assembled with an innovative technique based on CsI(Tl) scintillation crystals inserted into the square holes of a tungsten collimator. Characterization measurements have been performed on three detectors with different crystal size, in order to obtain 7 Â 7, 8 Â 8 and 9 Â 9 arrays over the fixed area of 25.7 Â 25.7 mm 2 , having the same overall dimensions of a Position Sensitive Photomultiplier Tube. Detector sensitivity, energy resolution and spatial resolution have been measured, and the acquired image quality has been evaluated with particular attention to pixel identification capability. r
Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications - Proceedings of the 9th Conference, 2006
In principle, a scintillation imager made by a crystal array and a position-sensitive photomultip... more In principle, a scintillation imager made by a crystal array and a position-sensitive photomultiplier shows spatial non linearities at borders due to the undersampling of scintillation light distributions. To improve the response of such detectors a method has been carried out based on the comparison between experimental and simulated images. A computer simulation code has been developed and used to foresee the imager response. The code computes the tapered charge-weighting factors giving the optimized event centroiding in terms of crystal-pixel identification. The comparison between measured centroids and crystal axes produces the effective correction table for image linearization. Experimental results concerning a 8x8 crystal array coupled to a position sensitive photomultiplier tube (1 inch square) are presented and discussed.
Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications - Proceedings of the 9th Conference, 2006
The feasibility of a subminiature scintillation detector to be inserted in a catheter for lesion ... more The feasibility of a subminiature scintillation detector to be inserted in a catheter for lesion localization in nuclear medicine SPECT has been studied. Measurements on a simple laboratory setup have been performed and compared with Monte Carlo results. Further simulations, at 30keV and 140keV, concerning a configuration reproducing severe clinical conditions have shown poor lesion detectability. Several factors affecting the response have to be investigated to improve the capability of lesion localization characterizing such detector.
Sensors and Microsystems - Proceedings of the 10th Italian Conference, 2008
This work is aimed to study the feasibility of a low energy gamma-ray detector for nuclear medici... more This work is aimed to study the feasibility of a low energy gamma-ray detector for nuclear medicine to be inserted into a body cavity, duct, or vessel. The small dimension detector concept is based on a CsI:Tl scintillation crystal coupled to a Si Avalanche Photodiode (APD) mounted in a catheter. Due to the availability of 99m Tc in nuclear medicine departments, 140 keV photons have been considered for detector design. At this energy the response concerns a more extended volume nearby the cathector than in the case of beta emitting radiotracers. Monte Carlo simulations have been performed and results have then been compared to experimental ones. The latter have been obtained using a 57 Co radioisotopic source and a laboratory setup including a detector having dimensions not optimized coupled to a low-noise conventional electronics. Count rates and sensitivities have been measured approaching a point source to the detector along some paths and considering different background irradiation levels.
IEEE Symposium Conference Record Nuclear Science 2004., 2004
A computer simulation code has been developed in order to foresee the response of discrete scinti... more A computer simulation code has been developed in order to foresee the response of discrete scintillation imaging devices. DIscrete Scintillation Imager Simulator (DISIS) has been designed for imagers based on a scintillation array coupled to a position sensitive light sensor (like position sensitive photomultiplier tube or avalanche photodiode array) by a planar light guide. The simulator is a deterministic code that uses: (i) a model describing the single photon light distribution emerging from a crystal pixel for charge integrals evaluation; (ii) the assigned algorithm for centroid calculation and; (iii) the Gaussian spread for localizing, crystal by crystal, the events on the image. In particular DISIS allows us to study the spatial response over the imager field of view changing parameters individually. The imager optimization can be obtained searching an acceptable pixel identification. To this aim a good trade-off between the spread of light distribution, the light sampling capability over the lightsensor area and the centroiding algorithm has to be found.