Departament de Física

Josep Sempau Roma

Associate professor
Campus Sud (UPC), Edifici H-PavC, Despatx 21-10
Avda. Diagonal, 647
08028 Barcelona

Telèfon: +34 934016074
E-Mail: josep.sempauupc.edu
Web del grup de recerca: https://inte.upc.edu/en/research/groups/IONHE
Web personal: http://futur.upc.edu/JosepSempauRoma

Short CV

Dr. Josep Sempau holds a BSc in Physics (Univ. de Barcelona, 1989) and a PhD in Physics (Univ. Politècnica de Catalunya, UPC, 1996), having joined the UPC in 1991 following early work as a consultant in the private sector. After a postdoctoral fellowship at the Univ. of Michigan, he progressed through the ranks at UPC (Researcher, Senior Researcher) to his current position as Associate Professor (2017). His research focuses on the Monte Carlo (MC) simulation of ionizing radiation transport in matter for medical and industrial applications, yielding an H-index of 31 (ref: Clarivate WoS 2025). He is a main contributor or co-author of several widely adopted MC codes, including PENELOPE (distributed via the Nuclear Energy Agency) and PRIMO, each with over 3000 distributed copies; the PENELOPE extension penEasy; the fast simulator of external beam radiotherapy DPM; and the medical imaging code MANTIS (distributed via the US FDA). Dr. Sempau has also served in significant administrative roles, including Deputy Director of the Energy Technologies Institute (2013–2018), Associate Director of the School of Industrial Engineering of the UPC (2021), and Coordinator of the PhD Program on Nuclear Engineering (2008–2021).


1- Optimization of energy compensation layered structure of Geiger-Müller counters
Li, F.; Lv, S.; Qi, S.; Cheng, P.; Zeng, G.; Xiao, M.; Sempau, J.
Nuclear engineering and technology 57, 4, article 103300 (2025)

2- Transit-guided radiation therapy: a novel patient monitoring approach
Latorre, A.; Oses, G.; Antelo, G.; Serrano, S.; Mollà, M.; Sempau, J.; Jornet Sala, Núria
Radiotherapy and oncology 201, article 110580 (2024)

3- Monte Carlo simulation of the Varian TrueBeam flattened-filtered beams using a surrogate geometry in PRIMO
Rodríguez, M.; Sempau, J.; Brualla, L.
Radiation oncology 19, article 14 (2024)

4- On the beam hardening correction of the transit-guided radiation therapy attenuation model
Latorre, A.; Jornet Sala, Núria; Sempau, J.
Physica medica 112, article 102660 (2023)

5- Transit-guided radiation therapy: proof of concept of an on-line technique for correcting position errors using transit portal images
Latorre, A.; Delgado, P.; Lizondo, M.; Jornet Sala, Núria; Sempau, J.
Physics in medicine & biology 67, 155022: 1-155022: 22 (2022)

6- Monte Carlo verification of the holder correction factors for the radiophotoluminescent glass dosimeter used by the IAEA in international dosimetry audits
Sempau, J.; Kazantsev, P.; Izewskac, J.; Brualla, L.
Physica medica 86, 1-5 (2021)

7- PENELOPE/PRIMO-calculated photon and electron spectra from clinical accelerators
Brualla, L.; Rodríguez, M.; Sempau, J.; Andreo, P.
Radiation oncology 14, 6 (2019)

8- DPM as a radiation transport engine for PRIMO
Rodríguez, M.; Sempau, J.; Bäumer, C.
Radiation oncology 13, 256 (1)-256 (9) (2018)

9- RECORDS: improved reporting of Monte Carlo radiation transport studies
Sechopoulos, I.; Rogers, D.; Bazalova-Carter, M.; Sempau, J.
International journal of radiation oncology biology physics 101, 792-793 (2018)

10- Technical note: On the efficiency of variance reduction techniques for Monte Carlo estimates of imaging noise
Sharma, D.; Sempau, J.; Badano, A.
Medical physics 45, 629-634 (2018)

11- RECORDS: Improved reporting of Monte Carlo radiation transport studies: Report of the AAPM Research Committee Task Group 268
Sechopoulos, I.; Rogers, D.; Bazalova-Carter, M.; Bolch, W.; Heath, E.; McNitt-Gray, M.; Sempau, J.; Williamson, J.
Medical physics 45, e-1-e-5 (2018)

12- Monte Carlo calculation of beam quality correction factors in proton beams using detailed simulation of ionization chambers
Gomà, C.; Andreo Hernández, Pedro; Sempau, J.
Physics in medicine and biology 61, 2389-2406 (2016)

13- Validation of semi-quantitative methods for DAT SPECT: influence of anatomical variability and partial volume effect
Gallego, J.; Niñerola-Baizán, A.; Cot, A.; Sempau, J.
Physics in medicine and biology 60, 5925-5938 (2015)

14- Technical Note: Study of the electron transport parameters used in penelope for the Monte Carlo simulation of Linac targets
Rodriguez, M.; Sempau, J.; Brualla, L.
Medical physics 42, 2877-2881 (2015)

15- A geometrical model for the Monte Carlo simulation of the TrueBeam linac
Rodriguez, M.; Sempau, J.; Fogliata, A.; Cozzi, Luca; Sauerwein, W.; Brualla, L.
Physics in medicine and biology 60, N219-N229 (2015)

16- Monte Carlo-based dose calculation engine for minibeam radiation therapy
Martinez, I.; Sempau, J.; Prezado, Y.
Physica medica 30, 57-62 (2014)

17- "Monte Carlo simulation of TrueBeam flattening-filter-free beams using varian phase-space files: comparison with experimental data"
Belosi, M.; Rodriguez, M.; Fogliata, A.; Cozzi, Luca; Sempau, J.; Clivio, A.; Nicolini, G.; Vanetti, E.; Krauss, H.; Khamphan, C.; Fenoglietto, P.; Puxeu, J.; Fedele, D.; Mancosu, P.; Brualla, L.
Medical physics 41, 051707 (2014)

18- Output correction factors for nine small field detectors in 6 MV radiation therapy photon beams: A PENELOPE monte carlo study
Benmakhlouf, H.; Sempau, J.; Andreo Hernández, Pedro
Medical physics 41, 041711-1-041711-12 (2014)

19- A complete pseudo-geometry for the Monte Carlo simulation of TrueBeam linacs
Rodríguez, M.; Sempau, J.; Fogliata, A.; Brualla, L.
Strahlentherapie und onkologie 190, 64-64 (2014)

20- "Accurate estimation of dose distributions inside an eye irradiated with 106Ru plaques"
Brualla, L.; Sempau, J.; Zaragoza, F. J.; Wittig, A.; Sauerwein, W.
Strahlentherapie und onkologie 189, 68-73 (2013)

21- Spencer–Attix water/medium stopping-power ratios for the dosimetry of proton pencil beams
Gomà, C.; Andreo Hernández, Pedro; Sempau, J.
Physics in medicine and biology 58, 2509-2522 (2013)

22- A method for accurate zero calibration of asymmetric jaws in single-isocenter half-beam techniques
Hernandez, V.; Sempau, J.; Abella, R.; Lopez, M.; Perez, M.; Artigues, M.; Arenas, M.
Medical physics 40, 2 (2013)

23- PRIMO: A graphical environment for the Monte Carlo simulation of Varian and Elekta linacs
Rodriguez, M.; Sempau, J.; Brualla, L.
Strahlentherapie und onkologie 189, 881-886 (2013)

24- "Development and commissioning of a Monte Carlo photon beam model for the forthcoming clinical trials in microbeam radiation therapy"
Martinez, I.; Sempau, J.; Prezado, Y.
Medical physics 39, 119-131 (2012)

25- Electron irradiation of conjunctival lymphoma—Monte Carlo simulation of the minute dose distribution and technique optimization
Brualla, L.; Zaragoza, F. J.; Sempau, J.; Wittig, A.; Sauerwein, W.
International journal of radiation oncology biology physics 83, 1330-1337 (2012)

26- "A combined approach of variance-reduction techniques for the efficient Monte Carlo simulation of linacs"
Rodriguez, M.; Sempau, J.; Brualla, L.
Physics in medicine and biology 57, 3013-3024 (2012)

27- "Monte Carlo-based treatment planning system calculation engine for microbeam radiation therapy"
Martinez, I.; Sempau, J.; Prezado, Y.
Medical physics 39, 2829-2838 (2012)

28- "Comment on Monte Carlo calculation of the dose distributions of two Ru-106 eye applicators [Radiother Oncol 49 (1998) 191-196]"
Brualla, L.; Sempau, J.; Sauerwein, W.
Radiotherapy and oncology 104, 267-268 (2012)

29- "Retinoblastoma external beam photon irradiation with a special 'D'-shaped collimator: A comparison between measurements, Monte Carlo simulation and a treatment planning system calculation"
Brualla, L.; Mayorga, P.; Flühs, A.; Lallena, A.; Sempau, J.; Sauerwein, W.
Physics in medicine and biology 57, 7741-7751 (2012)

30- "Clinical applications of geometrical field matching in radiotherapy based on a new analytical solution"
Hernández, V.; Arenas, M.; Pons, F.; Sempau, J.
Medical dosimetry 36, 160-165 (2011)

31- "Monte Carlo-estimated dose distributions and dose volume histograms from Ru/Rh-106 plaques on a computerised tomography of the eye"
Brualla, L.; Fluehs, D.; Wittig, A.; Zimmermann, B.; Sempau, J.; Bornfeld, N.; Sauerwein, W.
Strahlentherapie und onkologie 187, 104-104 (2011)

32- The influence of the field setup on the dosimetry of abutted fields in single-isocenter half-beam techniques
Hernández, V.; Sempau, J.
Medical physics 38, 1468-1472 (2011)

33- "Performance of several active personal dosemeters in interventional radiology and cardiology"
Chiriotti, S.; Ginjaume, M.; Vaño, E.; Sanchez, R.; Fernandez, J.; Duch, M.; Sempau, J.
Radiation measurements 46, 1266-1270 (2011)

34- Development of a GPU-based Monte Carlo dose calculation code for coupled electron-photon transport
Jia, X.; Gu, X.; Sempau, J.; Choi, D.; Majumdar, A.; Jiang, S.
Physics in medicine and biology 55, 3077-3086 (2010)

35- Monte Carlo dosimetry for forthcoming clinical trials in x-ray microbeam radiation therapy
Martinez, I.; Sempau, J.; Fernández Varea, José María; Bravin, A.; Prezado, Y.
Physics in medicine and biology 55, 4375-4388 (2010)

36- The accuracy of EGSnrc, Geant4 and PENELOPE Monte Carlo systems for the simulation of electron scatter in external beam radiotherapy
Faddegon, B.; Kawrakow, I.; Koubychine, Y.A.; Perl, J.; Sempau, J.; Urban, L.
Physics in medicine and biology 54, 20 (2009)

37- Effect of oblique X-ray incidence in flat-panel computed tomography of the Breast
Badano, A.; Kyprianou, I.; Freed, M.; Jennings, R.; Sempau, J.
IEEE transactions on medical imaging 28, 696-702 (2009)

38- A general analytical solution to the geometrical problem of field matching in radiotherapy
Hernández, V.; Arenas, M.; Pons, F.; Sempau, J.
Medical physics 36, 4191-4196 (2009)

39- PenMesh-Monte Carlo radiation transport simulation in a triangle mesh geometry
Badal-Soler, A.; Kyprianou, I.; Banh, D.; Badano, A.; Sempau, J.
IEEE transactions on medical imaging 28, 1894-1901 (2009)

40- "The accuracy of EGSnrc, Geant4 and PENELOPE Monte Carlo systems for the simulation of electron scatter in external beam radiotherapy"
Koubychine, Y.A.; Sempau, J.
Physics in medicine and biology 54, 6155-6163 (2009)

41- Comparison between PENELOPE and electron Monte Carlo simulations of electron fields used in the treatment of conjunctival lymphoma
Brualla, L.; Palanco, R.; Witting, A.; Sempau, J.; Sauerwein, W.
Physics in medicine and biology 54, 5469-5481 (2009)

42- Determination of absorbed dose in water at the reference point D(r_0, heta_0) for and 192Ir HDR brachytherapy source using a Fricke systems
Austerlitz, C.; Mota, H.; Sempau, J.; Benhabib, S.; Campos, D.; Allison, R.; Dealmeida, C.; ZHU, D.; Sibata, D.
Medical physics 35, 5360-5365 (2008)

43- "Adaptación de penEasy/PENELOPE para el uso de la base de datos del OIEA sobre espacios de fase de aceleradores lineales y uniddes de cobaltoterapìa"
Duch, M.; Sempau, J.
Revista de física médica 9, 133-136 (2008)

44- "Bechmarking of Monte Carlo simulation of bresstrahlung from thick tarjets at radiotherapy energies"
Faddegon, B.; Asai , M.; Perl, J.; Ross, C.; Sempau, J.; Tinslay, J.; Salvat, F.
Medical physics , 4308-4317 (2008)

45- Quantification of dopaminergic neurotransmission SPECT studies with I-123-labelled radioligands. A comparison between different imaging systems and data acquisition protocols using Monte Carlo simulation
Crespo, C.; Gallego, J.; Cot, A.; Falcón, C.; Bullich Roig, Santiago; Pareto, D.; Aguiar, P.; Sempau, J.; Lomeña, F.; Calviño, F.; Pavia, J.; Ros, D.
European journal of nuclear medicine and molecular Imaging 35, 1334-1342 (2008)

46- "Chamber quality factors in 60Co for three plane-parallel chambers for the dosimetry of electrons, protons and heavier charged particles. Penelope Monte Carlo simulations"
Panettieri, V.; Sempau, J.; Andreo Hernández, Pedro
Physics in medicine and biology 53, 5917-5926 (2008)

47- "Monte Carlo simulation of a realistica anatomical phantom described by triangle meshes: Application to prostate brachytherapy imaging"
Sempau, J.
Radiotherapy and oncology 86, 99-103 (2008)

48- "Benchmarking of Monte Carlo simulation of bremsstrahlung from thick targets at radiotherapy energies"
Faddegon, B.; Asai , M.; Perl, J.; Ross, C.; Sempau, J.; Tinslay, J.; Salvat, F.
Medical physics 35, 4308-4317 (2008)

49- "Monte Carlo modelling of Germanium detectors for the measurement of low energy photons in internal dosimetry"
Sempau, J.
Radiation measurements 43, 510-515 (2008)

50- "Monte Carlo simulation of a realistic anatomical phantom described by triangle meshes: application to prostate brachytherapy imaging"
Badal, A.; Kyprianou, I.; Badano, A.; Sempau, J.
Radiotherapy and oncology 86, 99-103 (2008)

51- "Evaluation of scatter and partial volume effect corrections in the quantification of neuroreceptor SPET studies with 123I-labeled radioligands"
Gallego, J.; Crespo, C.; Aguiar, P.; Cot, A.; Falcón, C.; Sempau, J.
European journal of nuclear medicine and molecular Imaging 34, S262-S262 (2007)

52- "Adaptación de Penélope para el uso de una nueva base de datos del OIEA sobre espacios de fase de aceleradores lineales y unidades de cobaltoterapia"
Duch, M.; Sempau, J.; Fernández Varea, José María
Revista de física médica 8, 244-245 (2007)

53- "Nuevas herramientas para la descripción de geometrías complejas con Penelope: aplicación a la modelización de maniquís antropomórficos"
Badal, A.; Sempau, J.; Kyprianou, I.; Badano, A.
Revista de física médica 8, 247-247 (2007)

54- "On the comparison of dose distributions for high-energy x-ray beams in water phantoms with bone-equivalent heterogeneities"
Carrasco, P.; Fernández Varea, José María; Jornet, N.; Duch, M.; Panettieri, V.; Brualla, L.; Eudaldo, T.; Sempau, J.; Ginjaume, M.; Ribas Morales, Montserrat
Radiotherapy and oncology 84, 49-50 (2007)

55- "Monte Carlo simulation with penelope and a realistic anthropomorphic phantom described by triangle meshes"
Badal, A.; Kyprianou, I.; Badano, A.; Sempau, J.
Radiotherapy and oncology 84, S46-S46 (2007)

56- "Making MC fast enough for treatment planning"
Sempau, J.
Radiotherapy and oncology 84, S39-S39 (2007)

57- "New technologies for dose calculations in external therapy"
Sempau, J.
Radiotherapy and oncology 84, S3-S3 (2007)

58- "Anisotropic imaging performance in breast tomosynthesis"
Badano, A.; Kyprianou, I.; Jennings, R.; Sempau, J.
Medical physics 34, 4076-4091 (2007)

59- Modeling of high-energy contamination in SPECT Imaging using Monte Carlo Simulation
Cot, A.; Jané, E.; Sempau, J.; Falcón, C.; Bullich Roig, Santiago; Pavía, J.; Calviño, F.
IEEE transactions on nuclear science 53, 198-203 (2006)

60- "Monte Carlo Simulation in Electron Probe Microanalysis. Comparison of Different Simulation Algorithms"
Salvat, F.; Llovet, X.; Fernández Varea, José María; Sempau, J.
Microchimica acta 155, 67-74 (2006)

61- "MANTIS: combined x-ray, electron and optical Monte Carlo simulations of indirect radiation imaging systems"
Sempau, J.
Physics in medicine and biology 51, 1545-1561 (2006)

62- "Anisotropic imaging performance in indirect x-ray imaging detectors"
Badano, A.; Kyprianou, I.; Sempau, J.
Medical physics 33, 2698-2713 (2006)

63- "A package of Linux scripts for the parallelization of Monte Carlo simulations"
Sempau, J.
Computer physics communications 175, 440-450 (2006)

64- "Monte Carlo simulation of bremsstrahlung emission by electrons"
Salvat, F.; Fernández Varea, José María; Sempau, J.
Radiation physics and chemistry 75, 1201-1219 (2006)

65- "Configuration of the electron transport algorithm of PENELOPE to simulate ion chambers"
Sempau, J.
Physics in medicine and biology 51, 3533-3548 (2006)

66- "Monte Carlo simulation of X-ray emission using the general-purpose code PENELOPE"
Llovet, X.; Fernández Varea, José María; Sempau, J.
Surface and interface analysis 37, 1054-1058 (2005)

67- Absolute quantification in dopaminergic neurotransmission SPET imaging using a Monte Carlo-based scatter correction and fully 3D reconstruction
Cot, A.; Falcón, C.; Crespo, C.; Sempau, J.; Pareto, D.; Bullich Roig, Santiago; Lomeña, F.; Calviño, F.; Pavía, J.; Ros, D.
Journal of nuclear medicine 46, 1497-1504 (2005)

68- "Electron beam quality correction factors for plane-parallel ionization chambers: Monte Carlo calculations using the PENELOPE system"
Sempau, J.; Andreo Hernández, Pedro; Aldana, J.; Mazurier, J.; Salvat, F.
Physics in medicine and biology 49, 4427-4444 (2004)

69- "Study of the point spread function (PSF) for 123I SPECT imaging using Monte Carlo simulation"
Cot, A.; Sempau, J.; Pareto, D.; Bullich Roig, Santiago; Pavia, J.; Calviño, F.; Ros, D.
Physics in medicine and biology 49, 3125-3136 (2004)

70- "Experimental benchmarks of the Monte Carlo code PENELOPE"
Sempau, J.; Fernández Varea, José María; Acosta, E.; Salvat, F.
Nuclear instruments and methods in physics research. Section B, beam interaction 207, 107-123 (2003)

71- "Evaluation of the geometric, scatter, and septal penetration components in fan beam collimators using Monte Carlo simulation"
Cot, A.; Sempau, J.; Pareto, D.; Bullich Roig, Santiago; Pavía, J.; Calviño, F.; Ros, D.
IEEE transactions on nuclear science 49, 12-16 (2002)

72- "Automated measurement of radon daughters B--214 and Pb-214"
Cortes, G.; Sempau, J.; Ortega, M.
Nukleonika 46, 161-164 (2001)

73- "Monte Carlo simulation of electron beams from an accelerator head using PENELOPE"
Sempau, J.; Sánchez-Reyes, A.; Salvat, F.; Oulad Ben Tahar, H.; Fernández Varea, José María
Physics in medicine and biology , 1163-1186 (2001)

74- "Simulación mediante el método de Monte Carlo de campos conformados de electrones de un acelerador lineal de terapia"
Sánchez-Reyes, A.; Hernández, V.; Oulad Ben Tahar, H.; Asenjo, J.; Sempau, J.
Revista de física médica , 29-34 (2001)

75- "DPM, a fast, accurate Monte Carlo code optimized for photon and electron radiotherapy treatment planning dose calculations"
Sempau, J.; Wilderman, S.
Physics in medicine and biology 45, 2263-2291 (2000)

76- "Towards the elimination of Monte Carlo statistical fluctuation from dose volume histograms for radiotherapy treatment planning"
Sempau, J.
Physics in medicine and biology 45, 131-157 (2000)

77- "Practical aspects of Monte Carlo simulation of charged particle transport: Mixed algorithms and variance reduction techniques"
Salvat, F.; Fernández Varea, José María; Sempau, J.; Mazurier, J.
Radiation and environmental biophysics 1, 15-22 (1999)

78- "An algorithm for Monte Carlo simulation of coupled electron-photon transport"
Sempau, J.; Acosta, E.; Baró, J.; Fernández Varea, José María; Salvat, F.
Nuclear instruments and methods in physics research. Section B, beam interaction , 377-390 (1997)

79- "The assessment of the representativeness of data from dose rate monitoring stations"
Zähringer, M.; Sempau, J.
Radiation protection dosimetry 64, 275-282 (1996)

80- "Penelope: an algorithm for monte carlo simulation of the penetration and energy loss of electrons and positrons in matter"
Baro, J.; Sempau, J.; Fernández Varea, José María; Salvat, F.
Nuclear instruments and methods in physics research. Section B, beam interaction 1, 31-46 (1995)

81- "Simplified monte carlo simulation of elastic electron scattering in limited media"
Baró, J.; Sempau, J.; Fernández Varea, José María; Salvat, F.
Nuclear instruments and methods in physics research. Section B, beam interaction 1, 465-483 (1994)