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Author Llosa, G.; Trovato, M.; Barrio, J.; Etxebeste, A.; Muñoz, E.; Lacasta, C.; Oliver, J.F.; Rafecas, M.; Solaz, C.; Solevi, P. doi  openurl
  Title First Images of a Three-layer compton Telescope prototype for Treatment Monitoring in hadron Therapy Type Journal Article
  Year 2016 Publication Frontiers in Oncology Abbreviated Journal Front. Oncol.  
  Volume 6 Issue Pages 14 - 6pp  
  Keywords Compton camera; Compton telescope; hadron therapy; treatment monitoring; LaBr3  
  Abstract A Compton telescope for dose monitoring in hadron therapy is under development at IFIC. The system consists of three layers of LaBr3 crystals coupled to silicon photomulti-plier arrays. Na-22 sources have been successfully imaged reconstructing the data with an ML-EM code. Calibration and temperature stabilization are necessary for the prototype operation at low coincidence rates. A spatial resolution of 7.8 mm FWHM has been obtained in the first imaging tests.  
  Address [Llosa, Gabriela; Trovato, Marco; Barrio, John; Etxebeste, Ane; Munoz, Enrique; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Solaz, Carles; Solevi, Paola] Inst Fis Corpuscular IFIC CSIC UVEG, Valencia, Spain, Email: gabriela.llosa@ific.uv.es  
  Corporate Author Thesis  
  Publisher Frontiers Media Sa Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2234-943x ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000369799800001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ elepoucu @ Serial 2785  
Permanent link to this record
 

 
Author Muñoz, E.; Barrio, J.; Bemmerer, D.; Etxebeste, A.; Fiedler, F.; Hueso-Gonzalez, F.; Lacasta, C.; Oliver, J.F.; Romer, K.; Solaz, C.; Wagner, L.; Llosa, G. doi  openurl
  Title Tests of MACACO Compton telescope with 4.44 MeV gamma rays Type Journal Article
  Year 2018 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.  
  Volume 13 Issue Pages P05007 - 13pp  
  Keywords Compton imaging; Instrumentation for hadron therapy; Gamma detectors (scintillators, CZT, HPG, HgI etc); Photon detectors for UV, visible and IR photons (solid state) (PIN diodes, APDs, Si PMTs, G APDs, CCDs, EBCCDs, EMCCDs etc)  
  Abstract Hadron therapy offers the possibility of delivering a large amount of radiation dose to tumors with minimal absorption by the surrounding healthy tissue. In order to fully exploit the advantages of this technique, the use of real-time beam monitoring devices becomes mandatory. Compton imaging devices can be employed to map the distribution of prompt gamma emission during the treatment and thus assess its correct delivery. The Compton telescope prototype developed at IFIC-Valencia for this purpose is made of three layers of LaBr3 crystals coupled to silicon photomultipliers. The system has been tested in a 4.44 MeV gamma field at the 3 MV Tandetron accelerator at HZDR, Dresden. Images of the target with the system in three different positions separated by 10 mm were successfully reconstructed. This indicates the ability of MACACO for imaging the prompt gamma rays emitted at such energies.  
  Address [Munoz, E.; Barrio, J.; Etxebeste, A.; Lacasta, C.; Oliver, J. F.; Solaz, C.; Llosa, G.] Univ Valencia, CSIC, Inst Fis Corpuscular, Parque Cient,C Catedrat Jose Beltran 2, E-46980 Paterna, Valencia, Spain, Email: Enrique.Munoz@ific.uv.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1748-0221 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000431716900001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3575  
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Author Barrio, J.; Etxebeste, A.; Lacasta, C.; Muñoz, E.; Oliver, J.F.; Solaz, C.; Llosa, G. doi  openurl
  Title Performance of VATA64HDR16 ASIC for medical physics applications based on continuous crystals and SiPMs Type Journal Article
  Year 2015 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.  
  Volume 10 Issue Pages P12001 - 12pp  
  Keywords Solid state detectors; Photon detectors for UV, visible and IR photons (solid-state) (PIN diodes, APDs, Si-PMTs, G-APDs, CCDs, EBCCDs, EMCCDs etc); Front-end electronics for detector readout; Gamma detectors (scintillators, CZT, HPG, HgI etc)  
  Abstract Detectors based on Silicon Photomultipliers (SiPMs) coupled to continuous crystals are being tested in medical physics applications due to their potential high resolution and sensitivity. To cope with the high granularity required for a very good spatial resolution, SiPM matrices with a large amount of elements are needed. To be able to read the information coming from each individual channel, dedicated ASICs are employed. The VATA64HDR16 ASIC is a 64-channel, charge-sensitive amplifier that converts the collected charge into a proportional current or voltage signal. A complete assessment of the suitability of that ASIC for medical physics applications based on continuous crystals and SiPMs has been carried out. The input charge range is linear from 20 pC up to 55 pC. The energy resolution obtained at 511 keV is 10% FWHM with a LaBr3 crystal and 16% FWHM with a LYSO crystal. A coincidence timing resolution of 24 ns FWHM is obtained with two LYSO crystals.  
  Address [Barrio, J.; Etxebeste, A.; Lacasta, C.; Munoz, E.; Oliver, J. F.; Solaz, C.; Llosa, G.] Univ Valencia, CSIC, Inst Fis Corpuscular, Parque Cient,C Catedrat Jose Beltran 2, E-46980 Paterna, Spain, Email: John.Barrio@ific.uv.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1748-0221 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000369998500034 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 2548  
Permanent link to this record
 

 
Author Ros Garcia, A.; Barrio, J.; Etxebeste, A.; Garcia-Lopez, J.; Jimenez-Ramos, M.C.; Lacasta, C.; Muñoz, E.; Oliver, J.F.; Roser, J.; Llosa, G. doi  openurl
  Title MACACO II test-beam with high energy photons Type Journal Article
  Year 2020 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 65 Issue 24 Pages 245027 - 12pp  
  Keywords Compton imaging; Compton camera; proton therapy; LaBr3; test-beam; image reconstruction  
  Abstract The IRIS group at IFIC Valencia is developing a three-layer Compton camera for treatment monitoring in proton therapy. The system is composed of three detector planes, each made of a LaBr3<i monolithic crystal coupled to a SiPM array. Having obtained successful results with the first prototype (MACACO) that demonstrated the feasibility of the proposed technology, a second prototype (MACACO II) with improved performance has been developed, and is the subject of this work. The new system has an enhanced detector energy resolution which translates into a higher spatial resolution of the telescope. The image reconstruction method has also been improved with an accurate model of the sensitivity matrix. The device has been tested with high energy photons at the National Accelerator Centre (CNA, Seville). The tests involved a proton beam of 18 MeV impinging on a graphite target, to produce 4.4 MeV photons. Data were taken at different system positions of the telescope with the first detector at 65 and 160 mm from the target, and at different beam intensities. The measurements allowed successful reconstruction of the photon emission distribution at two target positions separated by 5 mm in different telescope configurations. This result was obtained both with data recorded in the first and second telescope planes (two interaction events) and, for the first time in beam experiments, with data recorded in the three planes (three interaction events).  
  Address [Ros Garcia, A.; Barrio, J.; Etxebeste, A.; Lacasta, C.; Munoz, E.; Oliver, J. F.; Roser, J.; Llosa, G.] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain, Email: arosgar@ific.uv.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000600803000001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 4654  
Permanent link to this record
 

 
Author Roser, J.; Muñoz, E.; Barrientos, L.; Barrio, J.; Bernabeu, J.; Borja-Lloret, M.; Etxebeste, A.; Llosa, G.; Ros, A.; Viegas, R.; Oliver, J.F. doi  openurl
  Title Image reconstruction for a multi-layer Compton telescope: an analytical model for three interaction events Type Journal Article
  Year 2020 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 65 Issue 14 Pages 145005 - 17pp  
  Keywords Compton camera; Compton imaging; hadron therapy; image reconstruction; lm-mlem; monte carlo simulations; multi-layer Compton telescope  
  Abstract Compton Cameras are electronically collimated photon imagers suitable for sub-MeV to few MeV gamma-ray detection. Such features are desirable to enablein vivorange verification in hadron therapy, through the detection of secondary Prompt Gammas. A major concern with this technique is the poor image quality obtained when the incoming gamma-ray energy is unknown. Compton Cameras with more than two detector planes (multi-layer Compton Cameras) have been proposed as a solution, given that these devices incorporate more signal sequences of interactions to the conventional two interaction events. In particular, three interaction events convey more spectral information as they allow inferring directly the incident gamma-ray energy. A three-layer Compton Telescope based on continuous Lanthanum (III) Bromide crystals coupled to Silicon Photomultipliers is being developed at the IRIS group of IFIC-Valencia. In a previous work we proposed a spectral reconstruction algorithm for two interaction events based on an analytical model for the formation of the signal. To fully exploit the capabilities of our prototype, we present here an extension of the model for three interaction events. Analytical expressions of the sensitivity and the System Matrix are derived and validated against Monte Carlo simulations. Implemented in a List Mode Maximum Likelihood Expectation Maximization algorithm, the proposed model allows us to obtain four-dimensional (energy and position) images by using exclusively three interaction events. We are able to recover the correct spectrum and spatial distribution of gamma-ray sources when ideal data are employed. However, the uncertainties associated to experimental measurements result in a degradation when real data from complex structures are employed. Incorrect estimation of the incident gamma-ray interaction positions, and missing deposited energy associated with escaping secondaries, have been identified as the causes of such degradation by means of a detailed Monte Carlo study. As expected, our current experimental resolution and efficiency to three interaction events prevents us from correctly recovering complex structures of radioactive sources. However, given the better spectral information conveyed by three interaction events, we expect an improvement of the image quality of conventional Compton imaging when including such events. In this regard, future development includes the incorporation of the model assessed in this work to the two interaction events model in order to allow using simultaneously two and three interaction events in the image reconstruction.  
  Address [Roser, J.; Munoz, E.; Barrientos, L.; Barrio, J.; Bernabeu, J.; Borja-Lloret, M.; Etxebeste, A.; Llosa, G.; Ros, A.; Viegas, R.; Oliver, J. F.] Inst Fis Corpuscular IFIC CSIC UVEG, Valencia, Spain, Email: Jorge.Roser@ific.uv.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000552701600001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 4481  
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