Acoustic Localization of Bragg Peak Proton Beams for Hadrontherapy Monitoring

[EN] Hadrontherapy makes it possible to deliver high doses of energy to cancerous tumors by using the large energy deposition in the Bragg-peak. However, uncertainties in the patient positioning and/or in the anatomical parameters can cause distortions in the calculation of the dose distribution. In order to maximize the effectiveness of heavy particle treatments, an accurate monitoring system of the deposited dose depending on the energy, beam time, and spot size is necessary. The localized deposition of this energy leads to the generation of a thermoacoustic pulse that can be detected using acoustic technologies. This article presents different experimental and simulation studies of the acoustic localization of thermoacoustic pulses captured with a set of sensors around the sample. In addition, numerical simulations have been done where thermo-acoustic pulses are emitted for the specific case of a proton beam of 100 MeV.This research was funded by the Spanish Agencia Estatal de Investigacion, grant number FPA2015-65150-C3-2-P (MINECO/FEDER).Otero-Vega, JE.; Felis-Enguix, I.; Ardid Ramírez, M.; Herrero Debón, A. (2019). Acoustic Localization of Bragg Peak Proton Beams for Hadrontherapy Monitoring. Sensors. 19(9):1-13. https://doi.org/10.3390/s19091971S113199Kundu, T. (2014). Acoustic source localization. Ultrasonics, 54(1), 25-38. doi:10.1016/j.ultras.2013.06.009Bortfeld, T. (1997). An analytical approximation of the Bragg curve for therapeutic proton beams. Medical Physics, 24(12), 2024-2033. doi:10.1118/1.598116Ahmad, M., Xiang, L., Yousefi, S., & Xing, L. (2015). Theoretical detection threshold of the proton-acoustic range verification technique. Medical Physics, 42(10), 5735-5744. doi:10.1118/1.4929939Knapp, C., & Carter, G. (1976). The generalized correlation method for estimation of time delay. IEEE Transactions on Acoustics, Speech, and Signal Processing, 24(4), 320-327. doi:10.1109/tassp.1976.1162830Adrián-Martínez, S., Bou-Cabo, M., Felis, I., Llorens, C. D., Martínez-Mora, J. A., Saldaña, M., & Ardid, M. (2015). Acoustic Signal Detection Through the Cross-Correlation Method in Experiments with Different Signal to Noise Ratio and Reverberation Conditions. Lecture Notes in Computer Science, 66-79. doi:10.1007/978-3-662-46338-3_7Felis, I., Martínez-Mora, J., & Ardid, M. (2016). Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors. Sensors, 16(6), 860. doi:10.3390/s16060860Bragg, W. H., & Kleeman, R. (1905). XXXIX. On the α particles of radium, and their loss of range in passing through various atoms and molecules. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 10(57), 318-340. doi:10.1080/14786440509463378Janni, J. F. (1982). Energy loss, range, path length, time-of-flight, straggling, multiple scattering, and nuclear interaction probability. Atomic Data and Nuclear Data Tables, 27(2-3), 147-339. doi:10.1016/0092-640x(82)90004-3Jones, K. C., Seghal, C. M., & Avery, S. (2016). How proton pulse characteristics influence protoacoustic determination of proton-beam range: simulation studies. Physics in Medicine and Biology, 61(6), 2213-2242. doi:10.1088/0031-9155/61/6/2213Lai, H. M., & Young, K. (1982). Theory of the pulsed optoacoustic technique. The Journal of the Acoustical Society of America, 72(6), 2000-2007. doi:10.1121/1.388631Sigrist, M. W. (1986). Laser generation of acoustic waves in liquids and gases. Journal of Applied Physics, 60(7), R83-R122. doi:10.1063/1.337089Tam, A. C. (1986). Applications of photoacoustic sensing techniques. Reviews of Modern Physics, 58(2), 381-431. doi:10.1103/revmodphys.58.381Xiang, L., Han, B., Carpenter, C., Pratx, G., Kuang, Y., & Xing, L. (2012). X-ray acoustic computed tomography with pulsed x-ray beam from a medical linear accelerator. Medical Physics, 40(1), 010701. doi:10.1118/1.4771935Assmann, W., Kellnberger, S., Reinhardt, S., Lehrack, S., Edlich, A., Thirolf, P. G., … Parodi, K. (2015). Ionoacoustic characterization of the proton Bragg peak with submillimeter accuracy. Medical Physics, 42(2), 567-574. doi:10.1118/1.4905047De Bonis, G. (2009). Acoustic signals from proton beam interaction in water—Comparing experimental data and Monte Carlo simulation. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 604(1-2), S199-S202. doi:10.1016/j.nima.2009.03.072Kraan, A. C., Battistoni, G., Belcari, N., Camarlinghi, N., Cirrone, G. A. P., Cuttone, G., … Rosso, V. (2014). Proton range monitoring with in-beam PET: Monte Carlo activity predictions and comparison with cyclotron data. Physica Medica, 30(5), 559-569. doi:10.1016/j.ejmp.2014.04.003Patch, S. K., Hoff, D. E. M., Webb, T. B., Sobotka, L. G., & Zhao, T. (2017). Two-stage ionoacoustic range verification leveraging Monte Carlo and acoustic simulations to stably account for tissue inhomogeneity and accelerator-specific time structure - A simulation study. Medical Physics, 45(2), 783-793. doi:10.1002/mp.12681Lehrack, S., Assmann, W., Bertrand, D., Henrotin, S., Herault, J., Heymans, V., … Parodi, K. (2017). Submillimeter ionoacoustic range determination for protons in water at a clinical synchrocyclotron. Physics in Medicine & Biology, 62(17), L20-L30. doi:10.1088/1361-6560/aa81f8Hickling, S., Lei, H., Hobson, M., Léger, P., Wang, X., & El Naqa, I. (2017). Experimental evaluation of x-ray acoustic computed tomography for radiotherapy dosimetry applications. Medical Physics, 44(2), 608-617. doi:10.1002/mp.12039Ardid, M., Felis, I., Martínez-Mora, J. A., & Otero, J. (2017). Optimization of Dimensions of Cylindrical Piezoceramics as Radio-Clean Low Frequency Acoustic Sensors. Journal of Sensors, 2017, 1-8. doi:10.1155/2017/817967

Acoustic Bragg Peak Localization in Proton Therapy Treatment: Simulation Studies

[EN] A full chain simulation of the acoustic hadron therapy monitoring for brain tumors is presented in this work. For the study, a proton beam of 100 MeV was considered. In the first stage, Geant4 was used to simulate the energy deposition and to study the behavior of the Bragg peak. The energy deposition in the medium produced local heating that can be considered instantaneous with respect to the hydrodynamic time scale producing a sound pressure wave. The resulting thermoacoustic signal was subsequently obtained by solving the thermoacoustic equation. The acoustic propagation was simulated by the Finite Element Method (FEM) in the brain and the skull, where a set of piezoelectric sensors were placed. Lastly, the final received signals in the sensors were processed in order to reconstruct the position of the thermal source and, thus, to determine the feasibility and accuracy of acoustic beam monitoring in hadron therapy.Otero, J.; Felis, I.; Ardid Ramírez, M.; Herrero Debón, A.; Merchán, JA. (2019). Acoustic Bragg Peak Localization in Proton Therapy Treatment: Simulation Studies. MDPI. 1-7. https://doi.org/10.3390/ecsa-6-06533S1

Sporadic hemiplegic migraine and CREST syndrome

Hemiplegic migraines are characterised by attacks of migraine with aura accompanied by transient motor weakness. There are both familial and sporadic subtypes, which are now recognised as separate entities by the International Classification of Headache Disorders, edition II (ICHD-II). The sporadic subtype has been associated with other medical conditions, particularly rheumatological diseases. We report the case of a woman with sporadic hemiplegic migraine associated with CREST syndrome (calcinosis, Raynaud’s phenomenon, esophageal dysmotility, sclerodactyly and telangiectasia). Since there is a close relationship between migraine and Raynaud’s phenomenon, it could be speculated that the sporadic hemiplegic migraines in our patient might be secondary to CREST syndrome

Optimization of Dimensions of Cylindrical Piezoceramics as Radio-Clean Low Frequency Acoustic Sensors

[EN] Circular piezoelectric transducers with axial polarization are proposed as low frequency acoustic sensors for dark matter bubble chamber detectors. The axial vibration behaviour of the transducer is studied by three different methods: analytical models, FEM simulation, and experimental setup. To optimize disk geometry for this application, the dependence of the vibrational modes in function of the diameter-to-thickness ratio from 0.5 (a tall cylinder) to 20.0 (a thin disk) has been studied. Resonant and antiresonant frequencies for each of the lowest modes are determined and electromechanical coupling coefficients are calculated. From this analysis, due to the requirements of radiopurity and little volume, optimal diameter-to-thickness ratios for good transducer performance are discussed.The authors acknowledge the financial support of the Spanish Ministerio de Economia y Competitividad (MINECO), Grants FPA-2015-65150-C3-2P, and Consolider MultiDark CSD2009-00064. Thanks as well are due to the PICO Collaboration members for the fruitful discussions, suggestions, and comments.Ardid Ramírez, M.; Felis-Enguix, I.; Martínez Mora, JA.; Otero-Vega, JE. (2017). Optimization of Dimensions of Cylindrical Piezoceramics as Radio-Clean Low Frequency Acoustic Sensors. Journal of Sensors. 1-8. https://doi.org/10.1155/2017/81796721

Bragg Peak Localization with Piezoelectric Sensors for Proton Therapy Treatment

[EN] A full chain simulation of the acoustic hadrontherapy monitoring for brain tumours is presented in this work. For the study, a proton beam of 100 MeV is considered. In the first stage, Geant4 is used to simulate the energy deposition and to study the behaviour of the Bragg peak. The energy deposition in the medium produces local heating that can be considered instantaneous with respect to the hydrodynamic time scale producing a sound pressure wave. The resulting thermoacoustic signal has been subsequently obtained by solving the thermoacoustic equation. The acoustic propagation has been simulated by FEM methods in the brain and the skull, where a set of piezoelectric sensors are placed. Last, the final received signals in the sensors have been processed in order to reconstruct the position of the thermal source and, thus, to determine the feasibility and accuracy of acoustic beam monitoring in hadrontherapy.This research received was funded by the Spanish Agencia Estatal de Investigacion, grant numbers FPA2015-65150-C3-2-P (MINECO/FEDER) and PGC2018-096663-B-C43 (MCIU/FEDER).Otero-Vega, JE.; Felis-Enguix, I.; Herrero Debón, A.; Merchán, JA.; Ardid Ramírez, M. (2020). Bragg Peak Localization with Piezoelectric Sensors for Proton Therapy Treatment. Sensors. 20(10):1-12. https://doi.org/10.3390/s20102987S1122010A population-based assessment of proton beam therapy utilization in California. (2020). The American Journal of Managed Care, 26(2), e28-e35. doi:10.37765/ajmc.2020.42398Dutz, A., Agolli, L., Bütof, R., Valentini, C., Baumann, M., Lühr, A., … Krause, M. (2020). Neurocognitive function and quality of life after proton beam therapy for brain tumour patients. Radiotherapy and Oncology, 143, 108-116. doi:10.1016/j.radonc.2019.12.024Lesueur, P., Calugaru, V., Nauraye, C., Stefan, D., Cao, K., Emery, E., … Thariat, J. (2019). Proton therapy for treatment of intracranial benign tumors in adults: A systematic review. Cancer Treatment Reviews, 72, 56-64. doi:10.1016/j.ctrv.2018.11.004Amaldi, U., Bonomi, R., Braccini, S., Crescenti, M., Degiovanni, A., Garlasché, M., … Zennaro, R. (2010). Accelerators for hadrontherapy: From Lawrence cyclotrons to linacs. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 620(2-3), 563-577. doi:10.1016/j.nima.2010.03.130Weber, D. C., Abrunhosa-Branquinho, A., Bolsi, A., Kacperek, A., Dendale, R., Geismar, D., … Grau, C. (2017). Profile of European proton and carbon ion therapy centers assessed by the EORTC facility questionnaire. Radiotherapy and Oncology, 124(2), 185-189. doi:10.1016/j.radonc.2017.07.012MIZUMOTO, M., OSHIRO, Y., YAMAMOTO, T., KOHZUKI, H., & SAKURAI, H. (2017). Proton Beam Therapy for Pediatric Brain Tumor. Neurologia medico-chirurgica, 57(7), 343-355. doi:10.2176/nmc.ra.2017-0003Sulak, L., Armstrong, T., Baranger, H., Bregman, M., Levi, M., Mael, D., … Learned, J. (1979). Experimental studies of the acoustic signature of proton beams traversing fluid media. Nuclear Instruments and Methods, 161(2), 203-217. doi:10.1016/0029-554x(79)90386-0Aso, T., Kimura, A., Tanaka, S., Yoshida, H., Kanematsu, N., Sasaki, T., & Akagi, T. (2005). Verification of the dose distributions with GEANT4 simulation for proton therapy. IEEE Transactions on Nuclear Science, 52(4), 896-901. doi:10.1109/tns.2005.852697Jones, K. C., Witztum, A., Sehgal, C. M., & Avery, S. (2014). Proton beam characterization by proton-induced acoustic emission: simulation studies. Physics in Medicine and Biology, 59(21), 6549-6563. doi:10.1088/0031-9155/59/21/6549Jones, K. C., Seghal, C. M., & Avery, S. (2016). How proton pulse characteristics influence protoacoustic determination of proton-beam range: simulation studies. Physics in Medicine and Biology, 61(6), 2213-2242. doi:10.1088/0031-9155/61/6/2213Donnelly, B. R., & Medige, J. (1997). Shear Properties of Human Brain Tissue. Journal of Biomechanical Engineering, 119(4), 423-432. doi:10.1115/1.2798289Gu, L., Chafi, M. S., Ganpule, S., & Chandra, N. (2012). The influence of heterogeneous meninges on the brain mechanics under primary blast loading. Composites Part B: Engineering, 43(8), 3160-3166. doi:10.1016/j.compositesb.2012.04.014Peterson, J., & Dechow, P. C. (2003). Material properties of the human cranial vault and zygoma. The Anatomical Record, 274A(1), 785-797. doi:10.1002/ar.a.10096Fellah, Z. E. A., Chapelon, J. Y., Berger, S., Lauriks, W., & Depollier, C. (2004). Ultrasonic wave propagation in human cancellous bone: Application of Biot theory. The Journal of the Acoustical Society of America, 116(1), 61-73. doi:10.1121/1.1755239Raffaele, L. (2016). Advances in hadrontherapy dosimetry. Physica Medica, 32, 187. doi:10.1016/j.ejmp.2016.07.323Dosanjh, M., Amaldi, U., Mayer, R., & Poetter, R. (2018). ENLIGHT: European network for Light ion hadron therapy. Radiotherapy and Oncology, 128(1), 76-82. doi:10.1016/j.radonc.2018.03.014Ahmad, M., Xiang, L., Yousefi, S., & Xing, L. (2015). Theoretical detection threshold of the proton-acoustic range verification technique. Medical Physics, 42(10), 5735-5744. doi:10.1118/1.4929939Smith, A., Gillin, M., Bues, M., Zhu, X. R., Suzuki, K., Mohan, R., … Matsuda, K. (2009). The M. D. Anderson proton therapy system. Medical Physics, 36(9Part1), 4068-4083. doi:10.1118/1.3187229Yock, T. I., & Tarbell, N. J. (2004). Technology Insight: proton beam radiotherapy for treatment in pediatric brain tumors. Nature Clinical Practice Oncology, 1(2), 97-103. doi:10.1038/ncponc0090Riva, M., Vallicelli, E. A., Baschirotto, A., & De Matteis, M. (2018). Acoustic Analog Front End for Proton Range Detection in Hadron Therapy. IEEE Transactions on Biomedical Circuits and Systems, 12(4), 954-962. doi:10.1109/tbcas.2018.2828703Acoustics Module User’s Guidehttps://doc.comsol.com/5.4/doc/com.comsol.help.aco/AcousticsModuleUsersGuide.pdfArdid, M., Felis, I., Martínez-Mora, J. A., & Otero, J. (2017). Optimization of Dimensions of Cylindrical Piezoceramics as Radio-Clean Low Frequency Acoustic Sensors. Journal of Sensors, 2017, 1-8. doi:10.1155/2017/8179672Otero, Felis, Ardid, & Herrero. (2019). Acoustic Localization of Bragg Peak Proton Beams for Hadrontherapy Monitoring. Sensors, 19(9), 1971. doi:10.3390/s19091971Levenberg, K. (1944). A method for the solution of certain non-linear problems in least squares. Quarterly of Applied Mathematics, 2(2), 164-168. doi:10.1090/qam/10666Geant4 A Simulation Toolkithttp://geant4-userdoc.web.cern.ch/geant4-userdoc/UsersGuides/ForApplicationDeveloper/BackupVersions/V10.5-2.0/fo/BookForApplicationDevelopers.pdfBarber, T. W., Brockway, J. A., & Higgins, L. S. (1970). THE DENSITY OF TISSUES IN AND ABOUT THE HEAD. Acta Neurologica Scandinavica, 46(1), 85-92. doi:10.1111/j.1600-0404.1970.tb05606.xAdrián-Martínez, S., Bou-Cabo, M., Felis, I., Llorens, C. D., Martínez-Mora, J. A., Saldaña, M., & Ardid, M. (2015). Acoustic Signal Detection Through the Cross-Correlation Method in Experiments with Different Signal to Noise Ratio and Reverberation Conditions. Lecture Notes in Computer Science, 66-79. doi:10.1007/978-3-662-46338-3_

Cost and energy efficient reconfigurable embedded platform using Spartan-6 FPGAs

Modern FPGAs with run-time reconfiguration allow the implementation of complex systems offering both the flexibility of software-based solutions combined with the performance of hardware. This combination of characteristics, together with the development of new specific methodologies, make feasible to reach new points of the system design space, and make embedded systems built on these platforms acquire more and more importance. However, the practical exploitation of this technique in fields that traditionally have relied on resource restricted embedded systems, is mainly limited by strict power consumption requirements, the cost and the high dependence of DPR techniques with the specific features of the device technology underneath. In this work, we tackle the previously reported problems, designing a reconfigurable platform based on the low-cost and low-power consuming Spartan-6 FPGA family. The full process to develop the platform will be detailed in the paper from scratch. In addition, the implementation of the reconfiguration mechanism, including two profiles, is reported. The first profile is a low-area and low-speed reconfiguration engine based mainly on software functions running on the embedded processor, while the other one is a hardware version of the same engine, implemented in the FPGA logic. This reconfiguration hardware block has been originally designed to the Virtex-5 family, and its porting process will be also described in this work, facing the interoperability problem among different families

Yeast and its derivatives as ingredients in the food industry

In the last 200 years, and still today, yeast is well known for its application in brewing, alcohol fermentation and wine and bread making. They are an endless source of new food ingredients and additives with excellent functional and nutritional properties, now through the use of innovative elaboration and fractionation techniques that come mainly from biotechnology. The book reviewed here contains fourteen chapters in 246 pages that deal with yeasts employed as food ingredients and their potential as Nutraceutics. It compiles the expertise of three Latin American institutionsthat have given priority to the generation of basic knowledge on yeast and set the grounds for the development of new technologies based on these microorganisms. This is a sample of the alternatives offered by yeast in the fields of food science and technology.Fil: Otero, Miguel A.. Instituto Cubano de Investigaciones de los Derivados de la Caña de Azúcar; CubaFil: Guerrero, Isabel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Investigación en Funcionalidad y Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wagner, Jorge Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cabello, Agustín J.. Instituto Cubano de Investigaciones de los Derivados de la Caña de Azúcar; CubaFil: Sceni, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: García, Roxana. Instituto Cubano de Investigaciones de los Derivados de la Caña de Azúcar; CubaFil: Soriano, Jorge. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Investigación en Funcionalidad y Tecnología de Alimentos; ArgentinaFil: Tomasini, Araceli. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Investigación en Funcionalidad y Tecnología de Alimentos; ArgentinaFil: Saura, Gustavo. Instituto Cubano de Investigaciones de los Derivados de la Caña de Azúcar; CubaFil: Almazán, Oscar. Instituto Cubano de Investigaciones de los Derivados de la Caña de Azúcar; Cub

Assessment of over-the-head resuscitation method in an inflatable rescue boat sailing at full speed. A non-inferiority pilot study

Introduction: Drowning is a public health problem. Interrupting the drowning process as soon as possible and starting cardiopulmonary resuscitation (CPR) can improve survival rates. Inflatable rescue boats (IRBs) are widely used worldwide to rescue drowning victims. Performing CPR in special circumstances requires adjusting the position based on the environment and space available. The aim of this study was to assess the quality of over-the-head resuscitation performed by rescuers aboard an IRB in comparison to standard CPR.Methods: A quasi-experimental, quantitative, cross-sectional pilot study was conducted. Ten professional rescuers performed 1 min of simulated CPR on a QCPR Resuscy Anne manikin (Laerdal, Norway) sailing at 20 knots using two different techniques: 1) standard CPR (S-CPR) and 2) over-the-head CPR (OTH-CPR). Data were recorded through the APP QCPR Training (Laerdal, Norway).Results: The quality of CPR was similar between S-CPR (61%) and OTH-CPR (66%), with no statistically significant differences (p = 0.585). Both the percentage of compressions and the percentage of correct ventilations did not show significant differences (p > 0.05) between the techniques.Conclusion: The rescuers can perform CPR maneuvers with acceptable quality in the IRB. The OTH-CPR technique did not show inferiority compared to S-CPR, making it a viable alternative when boat space or rescue conditions do not allow the conventional technique to be performed.Universidade de Vigo/CISU

Simple low-cost construction and calibration of accurate pneumotachographs for monitoring mechanical ventilation in low-resource settings

Assessing tidal volume during mechanical ventilation is critical to improving gas exchange while avoiding ventilator-induced lung injury. Conventional flow and volume measurements are usually carried out by built-in pneumotachographs in the ventilator or by stand-alone flowmeters. Such flow/volume measurement devices are expensive and thus usually unaffordable in low-resource settings. Here, we aimed to design and test low-cost and technically-simple calibration and assembly pneumotachographs. The proposed pneumotachographs are made by manual perforation of a plate with a domestic drill. Their pressure-volume relationship is characterized by a quadratic equation with parameters that can be tailored by the number and diameter of the perforations. We show that the calibration parameters of the pneumotachographs can be measured through two maneuvers with a conventional resuscitation bag and by assessing the maneuver volumes with a cheap and straightforward water displacement setting. We assessed the performance of the simplified low-cost pneumotachographs to measure flow/volume during mechanical ventilation as carried out under typical conditions in low-resource settings, i.e., lacking gold standard expensive devices. Under realistic mechanical ventilation settings (pressure- and volume-control; 200-600 mL), inspiratory tidal volume was accurately measured (errors of 2.1% on average and <4% in the worst case). In conclusion, a simple, low-cost procedure facilitates the construction of affordable and accurate pneumotachographs for monitoring mechanical ventilation in low- and middle-income countries

Profile of antiretroviral agents use in Colombia

Introduction: Since the beginning of the epidemic, human immunodeficiency virus (HIV) has taken more than 36 million lives. Objective: To determine the antiretroviral drug prescription patterns in a population of individuals with HIV infection in Colombia. Materials and methods: Cross-sectional study analyzing the profiles of patients treated with antiretroviral drugs between April 1st and September 30th, 2015. The sociodemographic, pharmacological, and comorbidity variables were identified. Individuals with a positive diagnosis of HIV of all ages and both genders were included. Results: We found 641 patients with a mean age of 39.0±17 years who were predominantly male (60.2%). The most used medications were lamivudine-zidovudine (51.6%), lopinavir-ritonavir (36%) and efavirenz (24.5%). The combination of lamivudine-zidovudine plus lopinavir-ritonavir was the most prescribed regimen (29.5%), but a total of 80 different regimens was identified. Being an adult between the ages of 45-64 years (OR=2.25; 95%CI 1.367-3.713) was associated with a greater probability of receiving 4 or more antiretrovirals. A total of 267 (41.6%) patients used at least one comedication (range: 1-18 drugs), especially anti-ulcer (57.3%), lipid-lowering (28.8%) and anti-hypertensive (28.5%) drugs. Conclusions: Patients undergoing antiretroviral treatment are receiving medications with elevated intrinsic values at the recommended doses and present comorbidities associated with chronic agerelated conditions. However, these patients receive a great variety of regimens that are not included in the clinical practice guidelines