New light-amplifier-based detector designs for high spatial resolution and high sensitivity CBCT mammography and fluoroscopy.

New cone-beam computed tomographic (CBCT) mammography system designs are presented where the detectors provide high spatial resolution, high sensitivity, low noise, wide dynamic range, negligible lag and high frame rates similar to features required for high performance fluoroscopy detectors. The x-ray detectors consist of a phosphor coupled by a fiber-optic taper to either a high gain image light amplifier (LA) then CCD camera or to an electron multiplying CCD. When a square-array of such detectors is used, a field-of-view (FOV) to 20 × 20 cm can be obtained where the images have pixel-resolution of 100 µm or better. To achieve practical CBCT mammography scan-times, 30 fps may be acquired with quantum limited (noise free) performance below 0.2 µR detector exposure per frame. Because of the flexible voltage controlled gain of the LA's and EMCCDs, large detector dynamic range is also achievable. Features of such detector systems with arrays of either generation 2 (Gen 2) or 3 (Gen 3) LAs optically coupled to CCD cameras or arrays of EMCCDs coupled directly are compared. Quantum accounting analysis is done for a variety of such designs where either the lowest number of information carriers off the LA photo-cathode or electrons released in the EMCCDs per x-ray absorbed in the phosphor are large enough to imply no quantum sink for the design. These new LA- or EMCCD-based systems could lead to vastly improved CBCT mammography, ROI-CT, or fluoroscopy performance compared to systems using flat panels.

[Difficulties in cataract surgery of patient with old glaucoma]. / Dificultati în chirurgia cristalinului la bolnavul vechi glaucomatos.

Cataract surgery of glaucoma patients treated with Pilocarpine several years, with a small and miotic pupil, with synechiae is an important problem of management. The self-retaining flexible iris retractor is a microsurgical innovation that allows adequate enlargement of the pupil without iris incision. Each retractor is inserted through a separate self-sealing beveled incision made as far posteriorly in the cornea as possible. The retractors are spaced 90 degree apart and can easily be removed following implant insertion. The conclusion is that if we obtain an adequate enlargement of the pupil we can choose any cataract surgery technique, even phacoemulsification or EEC.

[Photodynamic therapy in ophthalmology]. / Terapia fotodinamica în oftalmologie.

This work presents the ophthalmic applications of photodynamic therapy (PDT). Very good results of PDT were observed in the treatment of neovascularization and tumors.

[The anterior segment ischemia syndrome]. / Sindromul de ischemie a segmentului anterior.

Starting from a clinical case, the paper presents a rare complication of the strabismus and retinal detachment surgery: the anterior segment ischemia syndrome. In this context, we discuss the clinical and pathogenetic circumstances of apparition, underlining the great importance of primary prophylaxis.