Sviluppo di una SPECT Camera per lo studio di Radiofarmaci “intelligenti” su piccoli animali

L'uso di radiofarmaci, tra le molteplici applicazioni delle radiazioni, trova completa giustificazione in campo medico. I radiofarmaci sono sostanze chimiche che, in quanto farmaci, hanno la proprietà di interagire specificatamente con il sistema biologico e che, contenendo nella loro struttura un atomo di un nuclide radioattivo emittente gamma (radiazione scarsamente assorbita dai tessuti biologici), consentono di seguirne il percorso biologico per mezzo di idonei rivelatori esterni. È così possibile costruire una serie di immagini, raccolte in tempi successivi, che individua la distribuzione del radiofarmaco nel corpo e ne evidenzia il progredire del metabolismo. In questo modo è possibile avere indicazioni, non solo morfologiche di organi e apparati, ma soprattutto informazioni sulla loro funzionalità. L'informazione clinica che si ottiene dall'analisi delle immagini scintigrafiche, dipende sostanzialmente dalle proprietà biologiche che il radiofarmaco possiede una volta iniettato in vivo. Se il radiofarmaco ha inoltre la proprietà di fissarsi specificamente in cellule tumorali, esso può diventare anche radioterapeutico. Basta infatti utilizzare nella "marcatura" un radionuclide che emetta radiazioni adatte alla distruzione delle cellule tumorali (radiazioni corpuscolari a corto range nella materia biologica) perché il radiofarmaco affine ad esse, iniettato in vivo, trasporti l'agente terapeutico specificamente nella zona di azione

A 1 GS/s sampling digitizer designed with interleaved architecture (GSPS) for the LaBr3 detectors of the FAMU experiment

A fast continuous sampling digitizer has been designed to acquire fast scintillating detector signalfrom cerium activated lantanum bromide (LaBr3(Ce)) scintillation crystal. These are foreseenin the FAMU experiment which is aimed at spectroscopic measurements of muonic hydrogen,possibly providing insights into the so-called proton radius puzzle. The board, named GSPS,is implemented as an FMC mezzanine which hosts two off-the-shelf sampling ADC used in in-terleaved timing architecture, achieving a 1 GS/s sampling rate (with a 12-bit nominal accuracyover the first Nyquist interval of frequencies, ranging from DC to 500 MHz). Interleaved tech-nique allowed us to keep both lower production costs and simple acquisition system avoidingcomplex interface protocols like JESD204. The board will be described; the test setup and theused methodology to characterize the device will be explained; the achieved performances willbe shown and discussed. In particular it will be pointed out how the two interleaved ADCs can becalibrated in order to get the best performance. The different contributions to both noise and dis-tortion affecting the device will be analyzed applying general techniques for high-sampling-speedcontinuous ADCs. Lastly, future improvements will be introduced: in particular, the solutions weforesee to get a effective number of bits of about 10 over the whole first Nyquist interval will beenlightened

Comparison between a silicon PIN diode and a CsI(Tl) coupled to a silicon PIN diode for dosimetric purpose in radiology

The use of amorphous Si-PIN diodes showed interesting applications in detector research. Due to their properties and cost effective value, these devices can be used as small dosimeters for fast and real time dose evaluation. The responses of two different detectors to the measurement of X-ray total air KERMA are compared and presented, with the goal to get a dosimetric parameter directly during the X-ray patients exposure. A bare Si-PIN diode and a Si-PIN diode+CsI(Tl) scintillator were tested and compared to radiologic dosimeters. Both detector outputs were calibrated using a secondary reference standard (CAPINTEC PM 30 dosimeter), in order to analyze and discuss the dose and the energy dependence of the detectors in the range of radiologic interest (tube voltage: 40–140 kVp and additional filtration: 0 mm Al to 4 mm Al). The bare Si-PIN diode shows a very coherent response independently from the X-ray beam quality and from the additional filtration. The Si-PIN+CsI(Tl) detector, on the other hand, shows a high spread of the calibration curves as a function of the tube high voltage and the additional filtration. The presented results could be used to calibrate an image detector in dose

On field spectrometry for diagnostic X-ray beams: Comparison between innovative devices

The knowledge of X-ray beam spectrum should be of great interest for the optimization of diagnostic procedures, allowing to reduce the patient dose improving the image quality. In fact, only the spectrometric analysis permits a complete characterization of the photonic beam both under qualitative and quantitative aspects enabling attenuation studies and quality parameters evaluation. \ua9 2011 IEEE

A software tool for on field spectrometry of diagnostic X-ray beams2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)

Conventional radiology uses X-ray beams with polychromatic spectrum consisting of a bremsstrahlung continuous component - with an energy band known only by means of half value layer (HVL), filtration and kVp values - and fluorescence lines. However the knowledge of the spectrum is crucial to allow advanced improvements of the diagnostic imaging with the lowest dose administered to the patients. In order to overcome the difficulty to make direct spectrometry on the diagnostic beam, we developed a simulation software based on a parametric semi-empirical model, that is able to reconstruct the X-ray diagnostic spectrum from 10 keV to 140 keV. This software makes use of experimental parameters, which can be measured in real time by two different methods. In this paper the calibration of detection systems will be described and discussed. In addition, the experimental validation of the software will be illustrated