Radiant energy – Invisible radiant energy responsive electric signalling – With or including a luminophor
Reexamination Certificate
2001-08-08
2003-08-19
Hannaher, Constantine (Department: 2878)
Radiant energy
Invisible radiant energy responsive electric signalling
With or including a luminophor
C250S36100C, C250S369000
Reexamination Certificate
active
06608310
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a modular high spatial resolution scintigraphic device with multiple independent photomultipliers and with extensible visualisation area.
In particular, functional imaging systems with small field of view (see U.S. patent applications Ser. Nos. 09/202,894 (now U.S. Pat. No. 6,242,744) and 09/202,790 (now U.S. Pat. No. 6,236,605) in the name of Alessandro Soluri et al.) can be applied in Nuclear Medicine as localisation and diagnostic devices, of reduced weight and minimum size, in order to identify neoplasias with high spatial resolution. Use of said devices can also find application in the scintigraphic analysis of small animals, in order to experiment new radio-marked antibodies, specific for particular pathologies. Another field of application relates to the guided localisation of prostate and breast lesions, in order to identify the areas with higher uptake to be subjected to bioptic sampling, to integrate current radiographic and/or echographic techniques. Such devices can find further applications in Astrophysics and in industrial non destructive test systems.
In particular, the main use of the device relates to locating tumour lesions, especially in those techniques that require an adequate spatial precision such as biopsies (prostate and breast) or in radio-guided or radio-immune-guided surgery. To remove a tumour lesion, the surgeon needs to identify its location and, for this purpose, he/she normally uses the results of diagnostic investigations performed previously with techniques known as RX, CAT scans, NMR and traditional Scintigraphy.
However at the moment of the operation, after “opening” the part, the surgeon may need to locate even more precisely the area to be cut or removed and, for this purpose, he/she can employ a so-called “surgical probe”. After injecting into the patient a radio-pharmaceutical, which has the peculiarity of being fixed more specifically in tumour cells, the surgeon uses a probe to detect the gamma-rays emitted by the radioisotope, present in the molecules of the drug in the area examined at a given time. The probe is sensitive to the intensity and energy of the detected gamma radiation and provides analogue signals that are proportional to the radioisotope concentration measured in the region identified by a single channel collimator.
The detected signals are converted to digital form providing information, in a light or sound scale, about the intensity of the signals that fall within the selected energy window. The limitation is constituted by the impossibility of providing an image that describes the spatial map of the concentration of radio-pharmaceutical and that only provides the visualisation of the counts in the area identified by the collimator.
This technique can be replaced with the use of a scintigraphic device which, although its size is fairly reduced, nonetheless still has considerable bulk during the surgical operation. This information has a considerable advantage linked to the real time visualisation of any neoplastic lesions and the confirmation of their total elimination after the surgical removal. Moreover, non scintigraphic techniques exist which allow to locate the sampling areas for needle biopsy, but with limitations on the precision of the areas to sample. These techniques, essentially based on RX and echographic systems, do not use a functional analysis but rather a morphological one, so that biopsies are generally guided in a non specific way.
The limitations of current technologies are mainly due to the poor spatial resolution (about 1 cm) and to the considerable dimensions of current commercial gamma-cameras. Already the devices claimed by Soluri et al. (see U.S. patent applications Ser. Nos. 09/202,894 now U.S. Pat. No. 6,242,744) and 09/202,790), now U.S. Pat. No. 6,232,605) in addition to those claimed by Francesco De Notaristefani et al. (WO 96/37991), Sealock et al. (U.S. Pat. No. 5,783,829), Stan Majewski et al. (U.S. Pat. No. 5,864,141), Scibilia et al. (U.S. Pat. No. 6,021,341), propose improvements both in terms of spatial resolution and in terms of reduced size and weight. Nevertheless, in some applications, the required spatial resolution becomes a fundamental parameter, so it is necessary to improve spatial resolution. Already Soluri et al. have provided an alternative to traditional systems by flat gamma cameras with very limited dimensions. These devices are well suited for specific diagnostic applications, such as, Radio Immune Guided Surgery (RIGS), or Radio Guided Surgery (RGS), or Single Proton Emission Mammography (SPEM), and Positron Emission Mammography (PEM). These applications are only a minimal part of those possible, because single devices can find aplication also in radio guided biopsies, integrating current echographic and/or radiographic technique with scintigraphic ones.
One of the current limitations surely consists of the inability to retrieve the diagnostic information in the dead border zones between individual devices set side by side. In this case if the crystal covers a border area between two photomultipliers, both will see a portion of charge in correspondence with the existing border zone (dead zone). The ambiguity of the event in this case is not easy to forecast and consequently place a limitation to events that fall within the dead zone between neighbouring photomultipliers.
Another fundamental aspect is linked to the limitations imposed by the construction techniques of the Position Sensitive Photomultiplier Tubes (PSPMT). The various models of photomultipliers individually exhibit peripheral dead areas, having total dimensions that exceed the stated active area. This causes problems when photomultipliers set side by side and/or mutually connected are used (see Soluri et al.) in order to obtain flat devices, constituted by multiple individual elements. In these devices it is essential that the dead zone between two bordering photomultipliers be smaller than 8 mm, in such a way as to use the connections of the signals exiting individual photomultipliers to constitute a single sensitive collection area. The presence of photomultipliers dead zones sets an upper limit in coupling devices, with active area that is definitely smaller than the total sizes of the individual photomultipliers.
Therefore, one aim of the invention is to provide a scintigraphic system constituted by the coupling of modules with independent photomultipliers, and in which the Field Of View (FOV) is defined by the way in which the individual modules are spatially positioned, both covering coplanar and contiguous areas, and involving areas of more complex geometry. Reference is also made to a forecasting model (see Raffaele Scafe et al., copyright—software no. 2100001) which allows, in particular, to optimise the components of modular scintigraphic devices (discrete, suitable for panel assembly and individually collimated), based on scintillating crystal arrays, optical guides, PSPMT and electronic balancing networks optimised by the linearity of spatial response in the FOV, in terms of detectability of lesions according to their depth, size and uptake. Essentially, many individual modules can be coupled, each of which has its own dedicated electronics for calculating the detected event position.
Another aim of the invention is to obtain appropriate electronics, to identify unambiguously which photomultiplier was involved by the single event, in order to reconstruct the distribution map of all events observed by the entire device (constituted by the set of individual modules). This independence of the individual modules in calculating the event position over the entire device thus constitutes a substantial innovation relative to the single charge collection surface proposed by Soluri et al. in the past (see U.S. patent applications Ser. Nos. 09/202,894 (now U.S. Pat. No. 6,242,744) and 09/202,790) (now U.S. Pat. No. 6,232,605) in which the individual anode wires belonging to each photomultiplier were connected with the contiguous ones.
A f
Burgio Nunzio
Scafe' Raffaele
Schiaratura Alfiero
Soluri Alessandro
Browdy and Neimark , P.L.L.C.
C.N.R. - Consiglio Nazionale Delle Ricerche
Hannaher Constantine
Moran Timothy
LandOfFree
Modular high spatial resolution scintigraphic device with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Modular high spatial resolution scintigraphic device with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Modular high spatial resolution scintigraphic device with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3115937