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This paper describes the development of a proton Computed Tomography (pCT) apparatus able to reconstruct a map of stopping power useful for accurate proton therapy treatment planning and patient positioning. This system is based on two main components: a silicon microstrip tracker and a YAG:Ce crystal calorimeter. Each proton trajectory is sampled by the tracker in four points: two upstream and two downstream the object under test; the particle residual energy is measured by the calorimeter. The apparatus is described in details together with a discussion on the characterization of the hardware under proton beams with energies up to 175 MeV.

In this paper a proton Computed Radiography (pCR) apparatus for medical applications, realized by PRIMA (PRoton IMAging) Italian Collaboration, is described. The system is oriented to acquire tomography images and meets clinical demands for the use of protons in radiotherapy treatments. The approach proposed here is based on ‘single proton tracking’ method with Most Likely Path (MLP) reconstruction of the single particle. A pCR prototype, with a field of view of about 5×5 cm 2 and an acquisition time of the order of 10 s (10 kHz, 10 5 events), has been developed and tested with a 62 MeV proton beam at the INFN-Laboratori Nazionali del Sud (LNS). The apparatus architecture will be described and first proton radiographies will be shown.

Modern radiotherapy treatment techniques, such as intensity Modulated Radiation Therapy (IMRT) and protontherapy, require detectors with specific features, usually not available in conventional dosimeters. IMRT dose measurements, for instance, must face non-uniform beam fluences as well as a time-varying dose rate. Two-dimensional detectors present a great interest for dosimetry in beams with steep dose gradients, but they must satisfy a number of requirements and, in particular, they must exhibit high spatial resolution. With the aim of developing a dosimetric system adequate for 2D pre-treatment dose verifications, we designed a modular dosimetric device based on a monolithic silicon-segmented module. State and results of this work in progress are described in this article. The first 441 pixels, 6.29×6.29 cm 2 silicon module has been produced by ion implantation on a 50 μm thick p-type epitaxial layer. This sensor has been connected to a discrete readout electronics performing current integration, and has been tested with satisfactory results. In the final configuration, nine silicon modules will be assembled together to cover an area close to 20×20 cm 2 with 3969 channels. In this case, the readout electronics will be based on an ASIC capable to read 64 channels by performing current-to-frequency conversion.

The silicon tracker of the PAMELA apparatus has been assembled and it is ready to fly on-board the Russian satellite Resurs DK for a 3-year mission. The experiment will study, mainly, spectra of particles and antiparticles in cosmic rays. The magnetic spectrometer's primary goal is to precisely measure momenta of charged particles, whose trajectories have been bent by a permanent magnet. The detector is composed of 6 planes of double-sided silicon microstrip detectors, inserted between adjacent modules of a permanent magnet which produces an almost uniform magnetic field inside a rectangular cavity that particles cross. The spatial resolution of the detectors is about 3 μm for the bending coordinate. The development of such detectors required a complex manufacturing procedure in order to preserve the physical performance in a device suitable for a space mission. In the construction phase data originating from both beam tests and simulation helped to check the detector's characteristics and to optimize the achievable spatial resolution. The development and the final assembling of these detectors are described in this paper.

In this paper, we describe in detail the design and the construction of the magnetic spectrometer of the PAMELA experiment, that will be launched during 2003 to do a precise measurement of the energy spectra of the antimatter components in cosmic rays. This paper will mainly focus on the detailed description of the tracking system and on the solutions adopted to deal with the technical challenges that are required to build a very precise detector to be used in the hostile space environment.

The experiment Sileye-3/Alteino was placed on board the International Space Station on 27 April 2002. The instrument is constituted by a cosmic ray silicon detector and an electroencephalograph. The main scientific aims include the investigation of the Light Flash phenomenon, the study of astronaut brain activity in space when subject to cosmic rays, the measurement of the radiation environment and the nuclear abundances inside the ISS. The instrument cosmic ray detector was active for 130 hours. In addition 6 astronaut Light Flash observation sessions were held, resulting in the observation of this phenomenon on the ISS.

The Pamela apparatus will be launched at the end of 2002 on board of the Resurs DK Russian satellite. The tracking system, composed of six planes of silicon sensors inserted inside a permanent magnetic field was intensively tested during these last years. Results of tests have shown a good signal-to-noise ratio and an excellent spatial resolution, which should allow to measure the antiproton flux in an energy range from 80 MeV up to 190 GeV. The production of the final detector modules is about to start and mechanical and thermal tests on the tracking tower are being performed according to the specifications of the Russian launcher and satellite. r 2002 Elsevier Science B.V. All rights reserved.

The mixed-signal PRIMA-chip has been developed for sensitive-position silicon detector in proton imaging application. The chip is based upon the binary readout architecture which, providing fully parallel signal processing, is a good solution for high intensity radiation application. It includes 32-front-end channels with a charge preamplifier, a shaper and a comparator. In order to adjust the comparator thresholds, each channel contains a 8-bit DAC, programmed using an I2C like interface. The PRIMA-chip has been fabricated using the AMS 0.35 μm standard CMOS process and its performances have been tested coupling it to the detectors used in the tracker assembled for the pCT (proton Computed Tomography) apparatus.

Hadron therapy for tumor treatment is nowadays used in several medical centres. The main advantage in using protons or light ions beams is the possibility of tightly shaping the radiation dose to the target volume. Presently the spatial accuracy of the therapy is limited by the uncertainty in stopping power distribution, which is derived, for each treatment, from the photon attenuation coefficients measured by X-ray tomography. A direct measurement of the stopping powers will help in reducing this uncertainty. This can be achieved by using a proton beam and a detection system able to reconstruct a tomography image of the patient. As a first step towards such a system an apparatus able to perform a proton transmission radiography (pCR) has been designed. It consists of a silicon microstrip tracker, measuring proton trajectories, and a YAG:Ce calorimeter to determine the particle residual energy. Proton beam and laboratory tests have been performed on the system components prototypes: the main results will be shown and discussed.

The PRIMA (Proton IMAging) experiment is aimed at developing a proton Computed Tomography (pCT) prototype based on tracking single protons. Approaches to the pCT consist in the use of silicon microstrip detectors to measure the position and direction of individual protons before and after they traverse the phantom, in view to reconstruct the trajectory of each proton, and a calorimeter for measuring particle residual energy. A small prototype was tested, under 62 MeV proton beam at Laboratory Nazionali del Sud, (Catania Italy) and under 180 MeV proton beam at Svedberg Laboratories, Uppsala Universitet, (Uppsala Sweden). Several experiments concerning proton imaging, tomography and radiography, were carried out during these beam tests. Radiographies have been reconstructed with different methods: results show the good performances of the device, with spatial resolution fulfilling the stringent requirements of a pCT device.

Proton Computed Tomography (pCT) is a new imaging method with a potential for increasing accuracy of treatment planning and patient positioning in hadron therapy. A pCT system with small active area (5cm×5cm) has been already manufactured by authors. Tested under proton beams gave first promising results on radiography and tomographic reconstructions. Recent developments of a second prototype with large area (5×20cm2) in the perspective of a pre-clinical acquisition system is now being designed, details are given in this paper.

The PAMELA detector will fly at the beginning of 2004 on board the Russian satellite Resurs–DK for a 3-year mission designed to study mainly antiparticles in cosmic rays. The core of the apparatus is a magnetic spectrometer in which silicon microstrip detectors are employed. A dedicated simulation study, tuned on beam test data, is presented: it allows to determine the best position finding algorithm for different incidence angles.

In 1993 the L3 detector at LEP has been equipped with a Silicon Microstrip Detector (SMD). In this paper we give a full description of the various components of the SMD readout and DAQ system.

Proton therapy is a highly precise form of cancer treatment, which requires accurate knowledge of the dose delivered to the patient and verification of the correct patient position to avoid damage to critical normal tissues. The development of pCT (proton Computed Tomography) system represents an important feature for precise proton radiation treatment planning because it could permit the direct measurement of the proton stopping power distribution, improving the accuracy in dose calculus, and the patient's position. A pCT prototype was manufactured in order to demonstrate the capability to acquire, during treatments in proton therapy centers, radiographic and tomographic images according to clinical demands.

Proton Computed Tomography (pCT) is a medical imaging method, based on the use of proton beams with kinetic energy of the order of 250 MeV, aimed to directly measure the stopping power distribution of tissues (presently calculated from X-rays attenuation coefficients), thus improving the accuracy of treatment planning in hadron therapy. A pCT system should be capable to measure tissue electron densities with an accuracy better than 1% and with a spatial resolution better than 1 mm. The blurring effect due to multiple Coulomb scattering can be circumvented by single proton tracking. As a first step toward pCT, we designed a proton computed radiography (pCR) prototype capable to carry out a single projection. The pCR apparatus includes a tracker (based on identical tracker modules, each including a silicon microstrip detector) to measure proton trajectory and a calorimeter (made of four YAG:Ce optically separated crystals) to measure residual energy. The tracker modules have been extensively tested and calibrated with beta particles and 62 MeV protons. The calorimeter has been tested with 62MeV and 200MeV protons, as well. The tracker assembly and the test of the tracker modules coupled to the calorimeter are presently under way. Results from these experiments are presented in this contribution.

There is today a growing up interest in hadrons and light ions therapy for tumors treatment, and new projects are worldwide rising in this field. The main advantage in using these particles is the possibility of tightly shaping the radiation dose to the target volume, thanks to the peculiarities of their interaction with matter. Anyway, the spatial accuracy of proton therapy is presently limited by the uncertainty in stopping power distribution, which is calculated from the photon attenuation coefficients measured by X-ray tomography. This uncertainty could be reduced by directly measuring stopping powers with a proton beam. The main problem is that protons do not move along straight lines across the medium, because of multiple Coulomb scattering; single proton tracking is a promising way to collect as much as possible information in order to circumvent this difficulty. The goals of this project, supported by INFN (PRoton IMAgin experiment) and MIUR (PRIN 2006), are: a) to develop a proton computed radiography (pCR) prototype capable to carry out a single projection; b) to validate the prototype with pre-clinical studies; c) to conceive a configuration for a complete proton computed tomography (pCT) system. Our target is to detect protons with initial kinetic energy high enough to traverse a human thorso (250-270 MeV) with a particle rate of ~1MHz, in order to collect data within a time of the order of 1s, suitable to clinical demands. Trajectory parameters to be measured are entrance and exit angle, entrance and exit position in the cross plane and residual energy. These data could be used, for instance, as input of most-likely path calculations to carry out a mapping of tissue electron density ρe. The final pCT system should be able to measure electron density with an accuracy better than 1% and with a spatial resolution better than 1 mm. Following earlier studies we designed the system described in fig.1, whose construction is presently under way. The tracker is composed of 4 x-y planes (p1-p4) capable to measure x-y coordinates of particle trajectory. A possible particle path (a) is indicated as an example. Planes p1 and p2 measure entrance angle and position, the object under study is placed in the gap between planes 2 and 3; planes p3 and p4 measure exit angle and position. An additional plane (p5) is included in the architecture for phantom testing purposes. As an example, in the figure, plane p5 is placed within a phantom composed of many planar slabs (c). In real applications the phantom will be replaced by the patient. The distance D between entrance (or exit) planes is about 1cm. x-y planes are composed of two tracker modules, including two printed circuit boards each: a "front end" board, which carries a Si detector and its readout ASICs, and a "digital board," mounted piggyback to the former, with FPGA-based digital electronics. One of the two modules within the same x-y plane is flipped upside down and rotated by 90° with respect to the other, to measure both the x and y local trajectory coordinates. The detector is a 256-channels silicon microstrip sensor

Due to the features of modern radiotherapy techniques, such as Intensity Modulated Radiation Therapy (IMRT), Stereotactic Treatments with photons and proton therapy, where high spatial dose gradient are often present, detectors to be employed for two-dimensional dose verifications must satisfy narrow requirements. In particular, they have to exhibit high spatial resolution. For these applications, in the framework of the European Integrated project MAESTRO (LSHC-CT-2004-503564) and of the INFN experiment PRIMA, we designed a modular system based on a monolithic silicon segmented sensor. A single sensor has been coupled with readout electronics and tested with satisfactory results by using 6, 10 and 25MV X-rays from a LINAC at the University Hospital of Florence and 62MeV protons at INFN LNS Catania, following MAESTRO procedures. For photons, almost all the channels exhibit performances within project specifications (repeatability ≪0.5%, reproducibility ≪1%, deviation from linearity ≪1%, dose rate dependence ≪1%). For protons, the measured Spread Out Bragg Peak is in good agreement with the one measured with a single diode and the detector shows also a good linearity in the range 20–5000 cGy. The output factors are in agreement with those measured with ionization chamber, single diode or film, within experimental errors.

There is today a growing up interest in proton therapy for tumor treatment, because these particles permit to tightly shape the dose to the target. Anyway, the accuracy in the determination of dose distribution for proton therapy is presently limited by the uncertainty in stopping power distribution, which is calculated from the photon attenuation coefficients measured by X-ray tomography. A proton computed tomography apparatus (pCT) could be used to directly measure stopping power and reduce this uncertainty. The main problem with proton imaging is the blurring effect introduced by multiple Coulomb scattering, but single proton tracking is a promising technique to face this difficulty. As a first step toward a pCT system, we designed a proton radiography (pCR) prototype based on a silicon microstrip tracker to characterize particle trajectories and on a segmented YAG:Ce calorimeter to measure their residual energy. The target is to detect protons with initial kinetic energy in the range 250-270 MeV and with a particle rate of ∼1MHz. Design and development of the pCR prototype, as well as the characterization of its single components, are described in this article. Status of development of reconstruction algorithms capable to account for Coulomb scattering is reported too.

Lymph node metastasis is one of the most important factors influencing prognosis and further therapy in patients with cervical carcinoma. The aim of this study was to confirm the impact of nodal metastasis od disease-free interval in women with stage IB1 cancer of the uterine cervix.From June 1986 to December 1999 269 patients with stage IB1 cervical carcinoma were operated on. Two hundred thirty-six (87.84%) patients had class III and 33 (12.16%) class II radical hysterectomy, according to Piver's classification.The median number of the removed lymph nodes was 21. Positive lymph nodes were found in 71 (25.28%) patients. All patients with positive lymph nodes received postoperative adjuvant external beam radiotherapy. Patients with bulky nodal disease received also chemotherapy.Overall 5-year disease-free interval in 212 patients was 80%. Five-year disease-free interval for patients without lymph node metastasis was 91%, while it was 40% in those with lymph node metastasis (p0.0001).Surgical staging of cervical cancer, which includes pelvic and para-aortic lymphadenectomy,together with pathological data, can provide potentially useful information for the radiation oncologist and precise analysis of survival and prognostic risk factors.

Commercial off-the-shelf components have been tested for their use on the power supplies of the AMS and PAMELA experiments. The test has been performed using the CALLIOPE Co60 source at the Casaccia (Rome-Italy) Laboratory of ENEA according to the ESA/SCC 22900 specifications. The total dose for this test: was 30 krads. Measurements of relevant parameters for each component has been taken at 3, 10 and 30 krads. Annealing and ageing has also been performed according to the ESA specification. The results on the degradation of performances in discrete transistors, op amps, regulators and other analog and digital components are reported.

The PAMELA apparatus is dedicated to study cosmic rays on board of a satellite mission scheduled to start at the beginning of 2004. All the electronics components of such a mission have to be chosen carefully, because no replacement is possible after launch. Irradiation tests have been performed in order to study effects of highly ionizing particles on chips and to evaluate thresholds for Single Event Upset and Latch-up. The first effect, observed in digital components, is a radiation-induced change of state in a memory cell and gives rise to loss of the stored information. The second one, present also in analog components, happens when a parasitic conduction channel opens through the chip: this can fuse the component unless a protection circuit limits the current flow. Estimates of on-orbit fluxes and results of dedicated beam tests are reported.

The PAMELA equipment will be assembled in 2001 and installed on board the Russian satellite Resurs. PAMELA is conceived mainly to study the antiproton and positron fluxes in cosmic rays up to high ...

We provide in this paper a status report of the space experiment PAMELA. PAMELA aims primarily to measure the flux of antiparticles, namely antiprotons and positrons, in cosmic rays with unpreceden ...

We report the results of two beam tests performed in July and September 1995 at CERN using silicon microstrip detectors of various types: single sided, double sided with small angle stereo strips, double sided with orthogonal strips, double sided with pads. For the read-out electronics use was made of Preshape32, Premux128 and VA1 chips. The signal to noise ratio and the resolution of the detectors was studied for different incident angles of the incoming particles and for different values of the detector bias voltage. The goal of these tests was to check and improve the performances of the prototypes for the CMS Central Detector.

The design and construction of the silicon strip microvertex detector (SMD) of the L3 experiment at LEP are described. We present the sensors, readout electronics, data acquisition system, mechanical assembly and support, displacement monitoring systems and radiation monitoring system of the recently installed double-sided, double-layered SMD. This detector utilizes novel and sophisticated techniques for its readout.

We report test beam results on the overall system performance of two modules of the L3 Silicon Microvertex Detector exposed to a 50 GeV pion beam. Each module consists of two AC coupled double-sided silicon strip detectors equipped with VLSI readout electronics. The associated data acquisition system comprises an 8 bit FADC, an optical data transmission circuit, a specialized data reduction processor and a synchronization module. A spatial resolution of 7.5 mu;m and 14 mu;m for the two coordinates and a detection efficiency in excess of 99% are measured.

The readout electronics for the Vertex and Forward Muon detectors of the ZEUS experiment at HERA is presented. The system architecture, based on a multilevel modular hierarchical structure, and the system performance are outlined.

The purpose of this study was to investigate possible age-related differences in the physical stimulus-psychological response relationship. Young and older adult subjects moved their arm to three standard locations or extents (25 cm, 50 cm, and 75 cm) on a linear positioning device. Seven standard comparison combinations were presented 20 times each. Subjects were asked to determine whether the comparison was different from the standard. Just noticeable difference, constant error, absolute constant error, and Weber ratios were calculated. In contrast to previous studies, the results clearly indicate that the physical stimulus-psychological response magnitude relationship for location and extent movements is best described by a metathetic continuum. We offer an explanation to account for the differences between location and extent movements for the just noticeable difference and Weber ratio. The failure to find differences between the age groups suggests that age-related declines cannot be generalized to all perceptual systems.

A technique for drawing ‘silica plastic’ fibres is described, along with the transmission and mechanical characteristics of the fabricated fibres. A number of applications of these fibres is also reported, including computer interconnection systems, r.f. reference signal transmission and the propagation of laser radiation through optical fibres for use in surgery.

When angiopathic patients arrive in the hospital, they usually present symptomatologies caused by vascular occlusion with stoppage of flow or advanced stenosis with significant reduction of flow. This results in ischemia in the arterial region and stasis in the venous region. Thus total or partial vascular occlusions, almost always thrombotic (sometimes embolic for the arteries), comprise the essence of angiopathies, and represent 90% of the cases that come under our observation.

As far as therapy is concerned, atherosclerotic arteriopathy may be divided into acute and chronic forms. In acute embolic forms, therapy should be surgical. Only in cases of periph eral embolism or polyembolism, and in rare cases for which vascular surgery cannot be adopted, can thrombolysis be carried out with UK. In acute thrombotic forms, therapy should be medical, because a thrombus of recent formation is rich in fibrin and may be lyzed by UK. Total recanaliza tion takes place in 61% of cases treated, partial recanalization in 23%. Subse quently perviousness is maintained by adequate antithrombotic therapy. In chronic arteriopathy, the thrombus is lacking or almost lacking in fibrin and thrombolytic therapy is not indicated. Special therapeutic combinations are used containing platelet inhibitors (ticlopidine), antifibrin drugs (subcutaneous heparin), minor fibrinolytic agents (mesoglycan) and hemorheological drugs (pentoxyphylline). This therapy seems to give good results, as showed by the low percentage in amputation calculated on 2,565 patients treated and kept under observation for 5 years. Finally let us consider chronic progressive arteriopathy. This term indicates a very advanced stage, characterized by a gradual irreversible change for the worse leading towards gangrene. As a last resort, before amputating, a throm bolytic therapy with UK was tried to see if with strong fibrinolysis continued for 3 days amputation might be avoided. In a pilot study carried out on 12 patients, the angiographic data showed only partial lysis in small arteries or arterial branches. Clinical data showed reduction or disappearance of pain at rest in 80% of cases. In 70% of cases gangrene disappeared if it was initial and superfi cial, it was delimited if already in progress.