Therapy of age-related exudative macular degeneration with anti-vascular endothelial growth factor drugs: An Italian real life study

Aim: To evaluate the real utilization of ranibizumab and aflibercept in the daily management of patients with neovascular age-related macular degeneration (nAMD) treated at the Eye Clinic of Campania University L.Vanvitelli. Background: Therapy with anti-vascular endothelial growth factor represents the gold standard in wet age-related macular degeneration. There are nonreal life italian studies of this therapy in the literature. Objective: To analyze in our sample the post-therapy variations of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) observed at the end of a 12-month follow-up period. Methods: This real-life study analyzes 109 patients that underwent monthly checks for the first 4 months and then every 2 months until the end of the 12-month follow-up. The sample was first analyzed in its entirety, subsequently subdivided into 3 groups based on baseline BCVA, age, and the number of intravitreal injections performed, in order to identify possible predictive elements of the anti-VEGF response. Results: On average, patients underwent 4.16 ± 1.58 intravitreal anti-VEGF injections in 1 year. At the end of the 12-month follow-up, the patients’ average BCVA increased from 33.01 letters to 33.75 letters (+0.74 ± 9,4 letters), while the average CRT decreased from 346.86 µm to 265.39 µm (-81.47 ± 121 µm). Conclusion: The study shows the efficacy of anti-VEGF therapy in the stabilization of BCVA in nAMD, confirming the differences in visual outcomes compared to clinical trials, mainly for economic-organizational reasons

Scintillating fiber dosimeter for radiotherapy

Radiotherapy, together with chemotherapy and surgery, is one of the main methods applied in the fight against cancer; in order to increase the chances of a successful radiotherapy treatment the dose delivery to the tumor and the surrounding normal tissues has to be computed with high accuracy. Traditional dosimeters are accurate but single channel (ionization chambers and diodes) or non real-time (radiographic films) devices. At present there is no device water equivalent that can perform real-time and bidimensional measurements of a dose distribution. This article describes the development of a real-time dosimeter based on scintillating fibers for photon and electron beams; the fibers are made of polystyrene, that is water equivalent and thus tissue equivalent, allowing a direct dose calculation. Three prototypes (single and multichannel) have been assembled, consisting in small scintillators coupled to white fibers that carry the light to photomultiplier tubes. In this article the prototypes and the readout electronics are described, together with the results of the measurements with electron and photon beams with energy up to 20MeV (produced by linear accelerators Varian Clinac 1800 and 2100CD)

A time-of-flight detector for thermal neutrons from radiotherapy Linacs

Boron Neutron Capture Therapy (BNCT) is a therapeutic technique exploiting the release of dose inside the tumour cell after a fission of a 10B nucleus following the capture of a thermal neutron. BNCT could be the treatment for extended tumors (liver, stomach, lung), radio-resistant ones (melanoma) or tumours surrounded by vital organs (brain). The application of BNCT requires a high thermal neutron flux (> 5 × 108 n cm- 2 s- 1) with the correct energy spectrum (neutron energy 8 MeV) photon beam. In this framework, we have developed a real-time detector to measure the thermal neutron time-of -flight to compute the flux and the energy spectrum. Given the pulsed nature of Linac beams, the detector is a single neutron counting system made of a scintillator detecting the photon emitted after the neutron capture by the hydrogen nuclei. The scintillator signal is sampled by a dedicated FPGA clock thus obtaining the exact arrival time of the neutron itself. The paper will present the detector and its electronics, the feasibility measurements with a Varian Clinac 1800/2100CD and comparison with a Monte Carlo simulation

Real time spectrometer for thermal neutrons from radiotherapic accelerators

Radiotherapy accelerators can produce high energy photon beams for deep tumour treatments. Photons with energies greater than 8 MeV produce neutrons via photoproduction. The PHONES (PHOto NEutron Source) project is developing a neutron moderator to use the photoproduced neutrons for BNCT (Boron Neutron Capture Therapy) in hospital environments. In this framework we are developing a real time spectrometer for thermal neutrons exploiting the bunch structure of the beam. Since the beam is produced by a linear accelerator, in fact, particles are sent to the patient in bunches with a rate of 150-300 Hz depending on the beam type and energy. The neutron spectrum is usually measured with integrating detectors such as bubble dosimeters or TLDs, which integrate over a time interval and an energy one. We are developing a scintillator detector to measure the neutron spectrum in real time in the interval between bunches, that is in the thermal region. The signals from the scintillator are discriminated and sampled by a dedicated clock in a Cyclone II FPGA by Altera, thus obtaining the neutron time of flight spectrum. The exploited physical process in ordinary plastic scintillators is neutron capture by H with a subsequent γ emission. The measured TOF spectrum has been compared with a BF3 counter one. A dedicated simulation with MCNP is being developed to extract the energy spectrum from the TOF one. The paper will present the results of the prototype measurements and the status of the simulation

Neutron imaging in a hospital environment

16BNCT is a technique exploiting the capture conversion process of thermal neutrons in the reaction 10B(n,α)7Li to treat extended and radioresistant tumours. One of its main limitations is the lack of specificity of the boron compounds with respect to tumour cells, which needs to be studied with a dedicated neutron beam. This work, developed within the INFN PhoNeS project and carried out at the radiotherapy unit of the S. Anna Hospital in Como with a Varian Clinac 2100C/D, describes the possibility of neutron imaging, performed with the neutrons produced by a Linac detecting the alpha particles with a non depleted self-triggering microstrip silicon detector. Several trials have been made with solutions of 10B at different percentages, obtaining a minimum sensitivity of 1.9 nmol/cm2 . The paper describes the detector, the measurement setup and the first results with biological samples.noneS. SCAZZI ; D. BOLOGNINI; V. MASCAGNA; A. MATTERA; M. PREST; G. BARTESAGHI; V. CONTI; P. CAPPELLETTI; M. FRIGERIO; S. GELOSA; A. MONTI; A. OSTINELLI; G. GIANNINI; E. VALLAZZA; F. BASILICO; P. MAURIScazzi, S.; Bolognini, D.; Mascagna, V.; Mattera, A.; Prest, Michela; Bartesaghi, G.; Conti, V.; Cappelletti, P.; Frigerio, M.; Gelosa, S.; Monti, A.; Ostinelli, A.; Giannini, G.; Vallazza, E.; Basilico, F.; Mauri, P

A real time scintillating fiber dosimeter for gamma and neutron monitoring on radiotherapy accelerators

The quality of the radiotherapic treatment depends strongly on the capability to measure the dose released in the treated volume and the one absorbed by the surrounding volumes, which is mainly due to the scattered radiation produced by the primary beam interaction with the accelerator collimating system. Radiotherapy linear accelerators produce electron (6-20MeV) and photon (6, 18MV) irradiating fields up to 40 x 40 cm(2). Photons with energies greater than 8 MeV generate neutrons via photoproduction which are being studied for possible BNCT applications

Real time spectrometer for thermal neutrons from radiotherapic accelerators

Radiotherapy accelerators can produce high energy photon beams for deep tumour treatments. Photons with energies greater than 8 MeV produce neutrons via photoproduction. The PHONES (PHOto NEutron Source) project is developing a neutron moderator to use the photoproduced neutrons for BNCT (boron neutron capture therapy) in hospital environments. In this framework we are developing a real time spectrometer for thermal neutrons exploiting the bunch structure of the beam. Since the beam is produced by a linear accelerator, in fact, particles are sent to the patient in bunches with a rate of 150-300 Hz depending on the beam type and energy.The neutron spectrum is usually measured with integrating detectors such as bubble dosimeters or TLDs, which integrate over a time interval and an energy one. We are developing a scintillator detector to measure the neutron spectrum in real time in the interval between bunches, that is in the thermal region. The signals from the scintillator are discriminated and sampled by a dedicated clock in a Cyclone II FPGA by Altera, thus obtaining the neutron time of flight spectrum. The exploited physical process in ordinary plastic scintillators is neutron capture by H with a subsequent \u3b3 emission. The measured TOF spectrum has been compared with a BF3 counter one. A dedicated simulation with MCNP is being developed to extract the energy spectrum from the TOF one.The paper will present the results of the prototype measurements and the status of the simulation

A time-of-flight detector for thermal neutrons from radiotherapy Linacs

Boron Neutron Capture Therapy (BNCT) is a therapeutic technique exploiting the release of dose inside the tumour cell after a fission of a B-10 nucleus following the capture of a thermal neutron. BNCT could be the treatment for extended tumors (liver, stomach, lung), radio-resistant ones (melanoma) or tumours surrounded by vital organs (brain). The application of BNCT requires a high thermal neutron flux (> 5 x 10(8) n cm(-2) s(-1)) with the correct energy spectrum (neutron energy 8 MeV) photon beam. In this framework, we have developed a real-time detector to measure the thermal neutron time-of -flight to compute the flux and the energy spectrum. Given the pulsed nature of Linac beams, the detector is a single neutron counting system made of a scintillator detecting the photon emitted after the neutron capture by the hydrogen nuclei. The scintillator signal is sampled by a dedicated FPGA clock thus obtaining the exact arrival time of the neutron itself. The paper will present the detector and its electronics, the feasibility measurements with a Varian Clinac 1800/2100CD and comparison with a Monte Carlo simulation

A real time scintillating fiber dosimeter for gamma and neutron monitoring on radiotherapy accelerators

The quality of the radiotherapic treatment depends strongly on the capability to measure the dose released in the treated volume and the one absorbed by the surrounding volumes, which is mainly due to the scattered radiation produced by the primary beam interaction with the accelerator collimating system. Radiotherapy linear accelerators produce electron (6-20 MeV) and photon (6, 18 MV) irradiating fields up to 40 × 40 cm2. Photons with energies greater than 8 MeV generate neutrons via photoproduction which are being studied for possible BNCT applications. We have developed a prototype of a real time dosimeter with 1 mm diameter scintillating and clear fibers readout by multianode photomultipliers. For neutron applications, the fibers have been coupled with boron loaded scintillator. We will describe the dosimeter and the results of the tests comparing them to the ones obtained with the standard dosimeters

Neutronic characterization of the MEGAPIE target

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