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Author (up) Barrientos, L.; Borja-Lloret, M.; Casaña, J.V.; Dendooven, P.; Garcia Lopez, J.G.; Hueso-Gonzalez, F.; Jiméeez-Ramos, M.C.; Perez-Curbelo, J.; Ros, A.; Roser, J.; Senra, C.; Viegas, R.; Llosa, G. doi  openurl
  Title Gamma-ray sources imaging and test-beam results with MACACO III Compton camera Type Journal Article
  Year 2024 Publication Physica Medica Abbreviated Journal Phys. Medica  
  Volume 117 Issue Pages 103199 - 10pp  
  Keywords Hadron therapy; Compton camera; Scintillator crystals; Silicon photomultipliers  
  Abstract Hadron therapy is a radiotherapy modality which offers a precise energy deposition to the tumors and a dose reduction to healthy tissue as compared to conventional methods. However, methods for real-time monitoring are required to ensure that the radiation dose is deposited on the target. The IRIS group of IFIC-Valencia developed a Compton camera prototype for this purpose, intending to image the Prompt Gammas emitted by the tissue during irradiation. The system detectors are composed of Lanthanum (III) bromide scintillator crystals coupled to silicon photomultipliers. After an initial characterization in the laboratory, in order to assess the system capabilities for future experiments in proton therapy centers, different tests were carried out in two facilities: PARTREC (Groningen, The Netherlands) and the CNA cyclotron (Sevilla, Spain). Characterization studies performed at PARTREC indicated that the detectors linearity was improved with respect to the previous version and an energy resolution of 5.2 % FWHM at 511 keV was achieved. Moreover, the imaging capabilities of the system were evaluated with a line source of 68Ge and a point-like source of 241Am-9Be. Images at 4.439 MeV were obtained from irradiation of a graphite target with an 18 MeV proton beam at CNA, to perform a study of the system potential to detect shifts at different intensities. In this sense, the system was able to distinguish 1 mm variations in the target position at different beam current intensities for measurement times of 1800 and 600 s.  
  Address [Barrientos, L.; Borja-Lloret, M.; Casana, J. V.; Hueso-Gonzalez, F.; Perez-Curbelo, J.; Ros, A.; Roser, J.; Senra, C.; Viegas, R.; Llosa, G.] CSIC UV, Inst Fis Corpuscular IFIC, Valencia, Spain, Email: Luis.Barrientos@ific.uv.es  
  Corporate Author Thesis  
  Publisher Elsevier Sci Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1120-1797 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001145147400001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5892  
Permanent link to this record
 

 
Author (up) Barrientos, L.; Borja-Lloret, M.; Casaña, J.V.; Hueso-Gonzalez, F.; Ros, A.; Roser, J.; Senra, C.; Solaz, C.; Viegas, R.; Llosa, G. doi  openurl
  Title System characterization and performance studies with MACACO III Compton camera Type Journal Article
  Year 2023 Publication Radiation Physics and Chemistry Abbreviated Journal Radiat. Phys. Chem.  
  Volume 208 Issue Pages 110922 - 13pp  
  Keywords Compton camera; Scintillator crystals; Silicon photomultipliers  
  Abstract The IRIS group of IFIC-Valencia has developed a Compton camera prototype. The system detectors are made of Lanthanum (III) bromide scintillator crystals coupled to silicon photomultipliers. Two models of silicon photomultipliers arrays with different micro pixel pitch (25 and 50 μm) have been chosen as possible candidates to improve the response of the new system. Characterization studies with a 22Na point-like source have indicated that the 25 μm photodetector provided better performance in terms of energy resolution (5.2% FWHM at 511 keV) and angular resolution (6.9 degrees FWHM at 1275 keV), and more stability with temperature variations. In addition, MACACO III imaging capabilities have been assessed using a structure composed of thirty-seven 22Na point-like sources. Furthermore, in order to evaluate possible ways of improving the system performance, several studies have been carried out by means of simulations both in realistic and performance improved conditions. In this work, the system performance is evaluated for its future application in different areas.  
  Address [Barrientos, L.; Borja-Lloret, M.; Casana, J. V.; Hueso-Gonzalez, F.; Ros, A.; Roser, J.; Senra, C.; Solaz, C.; Viegas, R.; Llosa, G.] CSIC UV, Inst Fis Corpuscular IF, Valencia, Spain, Email: Luis.Barrientos@ific.uv.es;  
  Corporate Author Thesis  
  Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0969-806x ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000962800400001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 5511  
Permanent link to this record
 

 
Author (up) Hueso-Gonzalez, F.; Casaña, J.V.; Fernandez Prieto, A.; Gallas Torreira, A.; Lemos Cid, E.; Ros Garcia, A.; Vazquez Regueiro, P.; Llosa, G. doi  openurl
  Title A dead-time-free data acquisition system for prompt gamma-ray measurements during proton therapy treatments Type Journal Article
  Year 2022 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A  
  Volume 1033 Issue Pages 166701 - 9pp  
  Keywords Data acquisition; Dead time; Pile-up; Digital signal processing  
  Abstract In cancer patients undergoing proton therapy, a very intense secondary radiation is produced during the treatment, which lasts around one minute. About one billion prompt gamma-rays are emitted per second, and their detection with fast scintillation detectors is useful for monitoring a correct beam delivery. To cope with the expected count rate and pile-up, as well as the scarce statistics due to the short treatment duration, we developed an eidetic data acquisition system capable of continuously digitizing the detector signal with a high sampling rate and without any dead time. By streaming the fully unprocessed waveforms to the computer, complex pile-up decomposition algorithms can be applied and optimized offline. We describe the data acquisition architecture and the multiple experimental tests designed to verify the sustained data throughput speed and the absence of dead time. While the system is tailored for the proton therapy environment, the methodology can be deployed in any other field requiring the recording of raw waveforms at high sampling rates with zero dead time.  
  Address  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0168-9002 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000794040600002 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 5318  
Permanent link to this record
 

 
Author (up) Martin-Luna, P.; Esperante, D.; Casaña, J.V.; Fernandez Prieto, A.; Fuster-Martinez, N.; Rivas, I.G.; Gimeno, B.; Ginestar, D.; Gonzalez-Iglesias, D.; Hueso, J.L.; Leptin, H.A.; Llosa, G.; Martinez-Reviriego, P.; Riera, J.; Vazquez Regueiro, P.; Hueso-Gonzalez, F. doi  openurl
  Title Effects of the passive voltage divider in a photomultiplier tube: Analytical model, simulations and experimental validation Type Journal Article
  Year 2025 Publication Sensors and Actuators A-Physical Abbreviated Journal Sens. Actuator A-Phys.  
  Volume 381 Issue Pages 116057 - 11pp  
  Keywords Photomultiplier tube; Photodetector; Proton therapy; Passive voltage divider network; Monte Carlo simulation; Gain drift  
  Abstract The effects of the passive resistive voltage divider network in a photomultiplier tube (PMT) have been investigated by developing an in-house Monte Carlo simulation code and compared with experimental measurements and an analytical model. The simulation code follows an iterative procedure that takes into account the transport and amplification of the electrons within the device depending on the electrostatic fields produced by the electrode voltages. The PMT gain, dynode voltages, rise time and transit time have been studied as a function of the photocathode current and supply voltage. A good agreement between the analytical model, the simulations and numerous experimental measurements using a Hamamatsu R13408-100 PMT has been obtained. The simulation results endorse the use of logistic functions within the analytical model to account for the collection efficiency in the last dynode stages. This works deepens the understanding of passive voltage dividers and develops an advanced behavioral circuit model of photomultiplier tubes. Although validated fora single PMT, the proposed methodology is applicable to any PMT model. This aids in optimizing the design of fully active voltage dividers, to be applied in extremely pulsed applications with high count rates such as prompt gamma-ray imaging during proton therapy.  
  Address [Martin-Luna, Pablo; Esperante, Daniel; Casana, Jose Vicente; Fuster-Martinez, Nuria; Gimeno, Benito; Gonzalez-Iglesias, Daniel; Llosa, Gabriela; Martinez-Reviriego, Pablo; Hueso-Gonzalez, Fernando] CSIC UV, Inst Fis Corpuscular IFIC, C-Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: pablo.martin@uv.es;  
  Corporate Author Thesis  
  Publisher Elsevier Science Sa Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0924-4247 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001367545100001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 6354  
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Author (up) Migueis, F.; Casaña, J.V.; Garcia-Fernandez, D.; Hueso-Gonzalez, F.; Llosa, G.; Prieto, A.F.; Regueiro, P.V.; Rivas, I.G.; Ros, A.; Crespo, P.; Simoes, H. doi  openurl
  Title Sensitivity of coaxial prompt gamma-ray monitoring in heterogeneous geometries: A Monte Carlo simulation study Type Journal Article
  Year 2025 Publication Radiation Physics and Chemistry Abbreviated Journal Radiat. Phys. Chem.  
  Volume 232 Issue Pages 112639 - 11pp  
  Keywords Protons; Coaxial; Proton therapy; Prompt gamma rays; Monte Carlo; Range verification  
  Abstract Proton beams offer significant advantages over conventional radiotherapy due to their unique interaction with matter. Specifically, the ionization density caused by these beams is higher in a well-defined region (the Bragg peak) with a sharp decline in intensity beyond a specific depth. However, variations in proton range – often caused by changes in patient anatomy and morphology during treatment – can introduce uncertainties in dose distribution. To account for this, clinicians apply conservative margins, which limit the full potential of proton therapy. Efforts have been focused on developing proton range and dose distribution monitoring systems to reduce the need for large safety margins. These systems are based on detecting and analyzing the byproducts that result from the interaction between the proton beams and tissue. In this article, we focused specifically on a system that aims to detect photons called prompt gamma (PG) rays. We conducted Monte Carlo simulations of proton beams interacting with anthropomorphic phantoms of varying densities to simulate morphological changes. A single scintillation detector was positioned coaxially with the beam and behind the phantom to capture the emitted PG rays in each scenario. Our analysis focused on discrepancies in proton range that resulted from irradiating an anthropomorphic head phantom with varying brain tissue densities and detecting secondary particles resulting from these interactions. We observed potential correlations between gamma-ray signatures and variations in proton range and energy deposition, suggesting that this monitoring technique could be effective for real-world clinical applications.  
  Address [Migueis, F.; Crespo, P.; Simoes, H.] Lab Instrumentat Expt Particle Phys, Coimbra, Portugal, Email: fmemf@student.uc.pt  
  Corporate Author Thesis  
  Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0969-806x ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001448817200001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 6567  
Permanent link to this record
 

 
Author (up) Roser, J.; Barrientos, L.; Bello, P.; Borja-Lloret, M.; Calatayud, J.M.; Casaña, J.V.; Hueso-Gonzalez, F.; Perez-Curbelo, J.; Prado, S.; Ros, A.; Senra, C.; Viegas, R.; Torres-Espallardo, I.; Llosa, G. doi  openurl
  Title Radiopharmaceutical imaging of phantoms and patients with MACACO III Compton camera Type Journal Article
  Year 2025 Publication Physica Medica Abbreviated Journal Phys. Medica  
  Volume 132 Issue Pages 104928 - 8pp  
  Keywords Compton cameras; Gamma cameras; Radiopharmaceutical imaging  
  Abstract Background and purpose: The use of Compton cameras for imaging radioisotopes in nuclear medicine offers potential advantages over conventional gamma cameras in some aspects. In this work, we present the first results in this field with the Compton camera prototype MACACO III after a measurement campaign in La Fe Hospital (Valencia, Spain). Methods: Images of Derenzo-like phantoms filled with 18F-FDG and 131I-NaI have been obtained with MACACO III and, in the latter case, with gamma cameras available in the hospital. Subsequently, a metastatic lesion in a patient treated with 131I-NaI after thyroid gland resection was imaged. Results: The 18F-FDG phantom images show the prototype capability of identifying up to 4 mm diameter rods. The measurements with 131I-NaI-filled phantoms demonstrate the clear improvement of the spatial resolution attainable with MACACO III when compared with images obtained with the gamma cameras available in the hospital. Finally, the image of the patient metastatic lesion obtained with the Compton camera was found to be consistent with the gamma camera inspection image. Conclusion: These encouraging results demonstrate MACACO III's capability for radiopharmaceutical imaging and open a door for its application to nuclear medicine.  
  Address [Roser, Jorge; Barrientos, Luis; Borja-Lloret, Marina; Casana, Jose V.; Hueso-Gonzalez, Fernando; Perez-Curbelo, Javier; Ros, Ana; Senra, Cesar; Viegas, Rita; Llosa, Gabriela] UV, CSIC, Inst Fis Corpuscular IFIC, Valencia, Spain, Email: Jorge.Roser@ific.uv.es  
  Corporate Author Thesis  
  Publisher Elsevier Sci Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1120-1797 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001444562200001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 6557  
Permanent link to this record
 

 
Author (up) Viegas, R.; Roser, J.; Barrientos, L.; Borja-Lloret, M.; Casaña, J.V.; Lopez, J.G.; Jimenez-Ramos, M.C.; Hueso-Gonzalez, F.; Ros, A.; Llosa, G. doi  openurl
  Title Characterization of a Compton camera based on the TOFPET2 ASIC Type Journal Article
  Year 2023 Publication Radiation Physics and Chemistry Abbreviated Journal Radiat. Phys. Chem.  
  Volume 202 Issue Pages 110507 - 11pp  
  Keywords Compton camera; Hadron therapy; LaBr3; PETsys TOFPET2; Silicon photomultipliers  
  Abstract The use of Compton cameras for medical imaging and its interest as a hadron therapy treatment monitoring has increased in the last decade with the development of silicon photomultipliers. MACACOp is a Compton camera prototype designed and assembled at the IRIS group of IFIC-Valencia. This Compton camera is based on monolithic Lanthanum (III) Bromide crystals and silicon photomultipliers, and employs the novel TOFPET2 ASIC as readout electronics. This system emerged as an alternative to MACACO II prototype, with the aim of improving its limited time resolution. To test the performance of the ASIC in a Compton camera setup, the prototype was characterized, both in laboratory and in-beam. A time resolution of 1.5 ns was obtained after time corrections, which improves greatly the performance of the MACACO II. Moreover, the results obtained at high photon energies demonstrate the ability of the system to obtain 1 mm displacements of the reconstructed spots. The results reinforce the potential of the system as a monitoring device for hadron therapy.  
  Address [Viegas, R.; Roser, J.; Barrientos, L.; Borja-Lloret, M.; Casana, J., V; Hueso-Gonzalez, F.; Ros, A.; Llosa, G.] CSIC UV, Inst Fis Corpuscular IFIC, Valencia, Spain, Email: Rita.Viegas@ific.uv.es  
  Corporate Author Thesis  
  Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0969-806x ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000870840600006 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 5392  
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