Noise and Cluster Size Studies of ALPIDE-CMOS Pixel Sensor for pCT

The use of proton beam has been introduced in medical physics for therapeutic purposes in cancer treatment and it has been proven much more efficient than conventional X-ray. Treatment planning in proton therapy is usually provided with information from X-ray CT where X-ray attenuation in tissue is needed to be converted to proton stopping power. This conversion leads to several uncertainties because proton interacts with matter in a different way than the photon. An intuitive way to mitigate this problem is using charged particles as the basis for the CT-scan and this is the time when the idea of “Proton CT” came up. There are nearly 10 pCT prototypes worldwide and all are designed with two separate devices for proton tracking and calorimetry. Few recent studies discovered the potential of merging these two separate systems into one uniquely featured Digital Tracking Calorimeter (DTC). The DTC is made of multiple layers of Monolithic Active Pixel Sensor (MAPS) chips. In this study, ALPIDE chip has been brought in as MAPS for DTC. The ALPIDE was developed for the heavy-ion experiment at CERN to detect high energy charged particles. For pCT, ALPIDE is conceptually an ideal sensor because of its low power consumption and chip area with more than half a million pixels with in-pixel readout scheme. This thesis is carried out in three main parts: • Characterization of ALPIDE chip focusing particularly on chip’s threshold and fake hit rate. • Measuring radiation-induced effects on the sensor performance. • Analysing sensor response for different types of radiation. In addition, I contributed to Proton Beam Test at OCL, Oslo and analyzed the data afterward. This thesis also includes the analysis performed on proton beam data and significant findings from the analysis. This study represents a key contribution to pCT in terms of defining the sensor behavior and interpreting sensor response.Master's Thesis in PhysicsMAMN-PHYSPHYS39

Scalable Readout for Proton CT

Denne oppgaven er en del av arbeidet med å utvikle en prototype detektor for proton CT. Den tar for seg første del av data prosessering nødvendig får rekonstruksjon og analyse av dataene og debugging av systemet..Masteroppgave i informatikkINF399MAMN-INFMAMN-PRO

Studies for a proton tomography scanner

iMPACT, innovative Medical Proton Achromatic Calorimeter and Tracker, is a University of Padova and INFN project, funded by the European Research Council. The project aim is to design, develop and prototype an extremely fast and accurate proton Computed Tomography Scanner, with the ultimate goal of enabling the realization of a clinically viable proton Computed Tomography (pCT) system. Proton Computed Tomography is an extremely promising technique able to reconstruct density maps (images) of the human body with minimal dose release and high tissue density accuracy, a particularly critical feature in cancer hadron-therapy treatment planning. Hadron-therapy is a leading edge technique where protons or heavy-ions, instead of X-rays, are used to target and destroy the tumor within the human body. By exploiting the peculiar energy deposition distribution such highly ionizing, heavy particles exhibit, it is in fact possible to confine within a volume of few mm3 most of the energy released, hence sparing the healthy tissues surrounding the tumor. However, despite all its beneficial aspects, hadron-therapy is not yet widespread as other more established procedures, such as X-ray therapy. One of the reasons is that the current X-ray Computed Tomography (X-ray CT), currently used to produce body density maps, cannot deliver maps accurate enough to exploit the intrinsic accuracy of the hadron treatment. To precisely aim the hadron energy release with millimeter precision, it is in fact necessary to possess very accurate knowledge of the density it traverse before reaching the tumor. The idea standing behind the development of a pCT scanner is that using the same energy loss behaviour for both the imaging process and the treatment would improve the performance of the latter, the physical interaction process being the same. Currently, several pCT scanner prototypes are being developed around the world; pCT scanner technology however is still far from being applicable in a clinical environment, mainly due to the slow acquisition rates. The iMPACT project therefore plans to develop a pCT scanner able to overcome such limitations, leading the way toward medically sound apparatuses. This thesis work begins by displaying both limitations and advantages of the hadron-therapy technique; the pCT state-of-the-art is then reviewed, highlighting positive features as well as constraints that limit its applicability. The current state of the iMPACT scanner, which embeds a tracker system and a calorimeter, is illustrated and discussed. The thesis then focuses on the development of the calorimeter part of the scanner. The development of a Monte Carlo simulation is presented together with a calibration procedure based on data collected at proton beam tests. Additional studies with proton data are presented with an outlook on future developments.ope

Towards a novel small animal proton irradiation platform: the SIRMIO project

Background: Precision small animal radiotherapy research is a young emerging field aiming to provide new experimental insights into tumor and normal tissue models in different microenvironments, to unravel complex mechanisms of radiation damage in target and non-target tissues and assess efficacy of novel therapeutic strategies. For photon therapy, modern small animal radiotherapy research platforms have been developed over the last years and are meanwhile commercially available. Conversely, for proton therapy, which holds potential for an even superior outcome than photon therapy, no commercial system exists yet. Material and methods: The project SIRMIO (Small Animal Proton Irradiator for Research in Molecular Image-guided Radiation-Oncology) aims at realizing and demonstrating an innovative portable prototype system for precision image-guided small animal proton irradiation, suitable for installation at existing clinical treatment facilities. The proposed design combines precise dose application with in-situ multi-modal anatomical image guidance and in-vivo verification of the actual treatment delivery. Results and conclusions: This manuscript describes the status of the different components under development, featuring a dedicated beamline for degradation and focusing of clinical proton beams, along with novel detector systems for in-situ imaging and range verification. The foreseen workflow includes pre-treatment proton transmission imaging, complemented by ultrasonic tumor localization, for treatment planning and position verification, followed by image-guided delivery with on-site range verification by means of ionoacoustics (for pulsed beams) and positron-emission-tomography (PET, for continuous beams). The proposed compact and cost-effective system promises to open a new era in small animal proton therapy research, contributing to the basic understanding of in-vivo radiation action to identify areas of potential breakthroughs for future translation into innovative clinical strategies