Variable tilt angle, parallel hole collimator for single photon emission tomography
Introduction
The invention concerns the construction of a collimator in lead or other material for gamma cameras in the SPET (Single Photon Emission Tomography) field for nuclear medicine applications on humans or small animals; for use in radio isotope molecular imaging. The tiltable collimator allows you to easily obtain three-dimensional reconstructions with high spatial resolution for a limited field of view.

Technical features
The main feature of the invention is the ability of varying the angel of inclination of the collimator holes. The system is based on a series of collimators with parallel holes mounted on a tilting support that allows the various elements to rotate coherently and continuously around a fixed axis, allowing to acquire a series of planar images from a static detector placed in proximity of the object of interest. The small size of the instrument and its collimation system also allow the detector to be placed directly in contact with the patient, in a fixed position with respect to it, reaching levels of spatial resolution otherwise not obtainable by the other diagnostic tools in use. Through the acquisition of the various planar images deriving from the different projection angles, it is possible to reconstruct the tomographic image using the “move and add” technique. The system leads to a reduction of the dosimetric load and the simultaneous optimization of the usability of the method itself. In the known art there are solutions which require an alignment of different foils during their inclination which is very difficult to obtain and / or precision that is too accurate and difficult to ensure.
Possible Applications
- Breast cancer diagnosis: the apparatus can be placed under the breast and determine the malignancy of even small lesions and their location, ensuring a precise and unambiguous biopsy;
- Cardiac coronary artery perfusion examination: allows for the prevention of heart attack and evaluation of cardiac function to operate preventive strategies on cardiac patients.
Advantages
- Positioning close to the organ or tissue to be analyzed;
- High quality of the reconstructed image;
- Small size if the device;
- High spatial resolution: this new collimator prototype allows the detection and localization of sub-centimeter lesions;
- Reduction of imaging time or reduction of the patient’s radiation dose.