Medical Physics, Radiobiology and Radiation Protection Group

Coordinator: João Santos, PhD

Research Team (as of December 31^st 2019)

Group description and objectives

The Medical Physics, Radiobiology and Radiation Protection Group was formed in the beginning of 2008 housed by the IPO-Porto Research Center. Its members are mainly physicists and radiobiologists but also include other expertises such as radiopharmacy and clinical practitioners. It is the only Medical Physics and Radiobiology research group in Portugal whose activities are developed entirely in a hospital environment. The work of the group focuses on the application of the methodology of physics and radiobiology to solve specific problems related to health care, especially in the area of ionizing radiation, both from the perspective of the patient procedures optimization or in the perspective of the protection in the event of professional exposure to ionizing radiation. Being focused in the interaction of ionizing radiation and biological tissues, the question of radiation protection arises immediately. The group embraced already critical personal exposure due to highly heterogeneous radiation fields during the project “Dose distribution mapping and Monte Carlo simulations in CT-fluoroscopy” (PTDC/SAU-ENB/115792/2009) and patient exposure during intra-operatory radiotherapy during the project “IORT: the effect of shielding on dose distributions in intra-operative electron radiotherapy: a Monte Carlo simulations study.” (PTDC/SAU-ENB/117631/2010). Both these studies were complemented by Monte Carlo (MC) simulations. This methodology, with increasing computer power over the last years, is becoming a benchmark method to simulate “difficult-to-execute-in-practice” procedures in ionizing radiation physics, where exposure of subjects must be very well justified. Over the year of 2017, the group extended this methodology to external radiotherapy using Penelope based PRIMO software, which has become one of the main strategic lines of research. Monte Carlo methods are being used also in the field of Nuclear Medicine, both for imaging and radiation spectrum analysis and optimization.

The group is involved in several national and international collaborations such as Faculdade de Ciências da Universidade do Porto, Instituto de Ciências Biomédicas Abel Salazar da Universidade do Porto, Instituto Superior Técnico (IST/CTN), INESC Porto, Universidade de Aveiro (Dep. Eng. Mecânica; ), Universidade de Coimbra (Centro de Informática e Sistemas da Universidade de Coimbra; LIP), Faculdade de Ciências da Universidade de Lisboa, Universidade do Minho (MEMS), Institute of Nuclear Physics PAN, Radzikowskiego 152, PL 31-342 Krakow, Radiation Chemistry and Dosimetry Laboratory, Bijenička c. 54, HR-10000 Zagreb, Croatia, Greek Atomic Energy Commission (EEAE), Dosimetry and Calibration Department P.O. Box 60092, 153 10 Agia Paraskevi, Athens, Greece, SCK•CEN ǀ  Belgian Nuclear Research Centre, Unit Research in Dosimetric Applications, Boeretang 200 – BE-2400 Mol, among others.

The group has one Full Member (J.A.M. Santos) in the European Radiation Dosimetry Group (Eurados), and one Corresponding Member (J. Lencart), in the Workgroup 9, WG9 (Radiation Protection in Radiotherapy).

Active projects and funding

• “Incertezas geométricas em radioterapia externa” (CI-IPO 25 2015)
• “Resposta Biológica renal em PRRT e dosimetria geral” (CI-IPOP-65-2017)
• “fMRI na delineação de fOAR em SRS cranial” (CI-IPOP-65-2017)
• “PRO-DOSE – Dispositivo para dosimetria in-vivo em braquiterapia”, Projeto: 17816 : NU-RISE LDA (33/SI/2015): € 153.744,01 (IPO-Porto share to be used through 2018 and September 2019)

Major achievements in 2019 (based on the 5 most relevant publications for the group)

• Out-of-field scattered and transmitted extrafocal radiation may induce secondary cancer in long-term survivors of external radiotherapy. Pediatric patients have higher life expectancy and tend to receive higher secondary radiation damage due to geometric and biological factors. The goal of this study is to characterize the location and the magnitude of extrafocal dose regions in the case of three-dimensional conformal radiotherapy and volumetric arc therapy, to apply this information to clinical treatment cases, and to provide mitigation strategies. Extrafocal dose has been investigated in a Varian TrueBeam linac equipped with a high-definition 120 multileaf collimator using different physical and virtual phantoms, dose calculation (including Monte Carlo techniques), and dose measurement methods. All Monte Carlo calculations showed excellent agreement with measurements. Treatment planning system calculations failed to provide reliable results out of the treatment field. Both Monte Carlo calculations and dose measurements showed regions with higher dose (extrafocal dose areas) when compared to the background. These areas start to be noticeable beyond 11 cm from the isocenter in the direction perpendicular to the multileaf collimator leaves’ travel direction. Out-of-field extrafocal doses up to 160% of the mean dose transmitted through the closed multileaf collimator were registered. Two overlapping components were observed in the extrafocal distribution: the first is an almost elliptical blurred dose distribution, and the second is a well-defined rectangular dose distribution. Extra precautions should be taken into consideration when treating pediatric patients with a high-definition 120 multileaf collimator to avoid directing the extrafocal radiation into a radiosensitive organ during external beam therapy. (Characterization of extrafocal dose influence in the out-of-field dose distribution by Monte Carlo simulation and dose measurements, Firass Ghareeb, Joana Lencart, Jorge Oliveira, João A. M. Santos, Health Physics 2019 Nov;117(5):489-503, Localized extra focal dose collimator angle dependence during VMAT: An out-of-field Monte Carlo study using PRIMO software, Firass Ghareeb, Alessandro Espositob, Joana Lencart, João A.M.Santos, Radiation Physics and Chemistry Available online 8 January 2020, DOI: 10.1016/j.radphyschem.2020.108694)
• The IAEA newly developed “end-to-end” audit methodology for on-site verification of IMRT dose delivery has been carried out in Portugal in 2018. The main goal was to evaluate the physical aspects of the head and neck (H&N) cancer IMRT treatments. This paper presents the national results. All institutions performing IMRT treatments in Portugal, 20 out of 24, have voluntarily participated in this audit. Following the adopted methodology, a Shoulder, Head and Neck End-to-End phantom (SHANE) – that mimics an H&N region, underwent all steps of an IMRT treatment, according to the local practices. The measurements using an ionization chamber placed inside the SHANE phantom at four reference locations (three in PTVs and one in the spinal cord) and an EBT3 film positioned in a coronal plane were compared with calculated doses. FilmQA Pro software was used for film analysis. For ionization chamber measurements, the percent difference was within the specified tolerances of ±5% for PTVs and ±7% for the spinal cord in all participating institutions. Considering film analysis, gamma passing rates were on average 96.9%±2.9% for a criterion of 3%/3 mm, 20% threshold, all above the acceptance limit of 90%. The national results of the H&N IMRT audit showed a compliance between the planned and the delivered doses within the specified tolerances, confirming no major reasons for concern. At the same time the audit identified factors that contributed to increased uncertainties in the IMRT dose delivery in some institutions resulting in recommendations for quality improvement (IMRT national audit in Portugal, Tania Santos, Maria do Carmo Lopes, Eduard Gershkevitshc, FilipaVinagre, David Faria, LilianaCarita, Miguel Pontes, SandraVieira, Esmeralda Poli, Sofia Faustino, Filipa Ribeiro, Mauro Trindade, Fernanda Ponte, Carlos Marcelino. Cláudio Batista, Susana Oliveira, Rita Figueira, Joana Lencart, Ester Gallego, Diazs KatiaJacob, Sandra Brás, Rui Pirraco, Joanna Izewska, Physica Medica, 65 (2019)128-136)
• Insulinomas are a rare type of pancreatic neuroendocrine tumours characterized by insulin hypersecretion. They are considered malignant when metastases are present. Traditional therapies often promote only temporarily symptomatic relief and may be associated with severe adverse effects. There is scarce experience in treating malignant insulinomas with peptide receptors radionuclide therapy (PRRNT). We describe PRRNT results in four patients with inoperable malignant insulinomas with poorly controllable hypoglycaemia. All patients received therapy with 177Lu-DOTA-TATE after conventional therapies failed in controlling disease progression and symptoms. The activity administered per cycle was 4.8-7.4 GBq. The interval between cycles was 10-16 weeks. Haematology, liver and kidney function tests were performed before treatment initiation and 5 and 10 weeks after each cycle. Patient 1 presented significant clinical benefit for 13 months after PRRNT, with imaging improvement. Patient 2 obtained reduction of the number and severity of hypoglycaemic episodes during 15 months after therapy. Patient 3 is asymptomatic since PRRNT first cycle performed 23 months ago and revealed significant imaging improvement. Patient 4 had resolution of hypoglycaemia only 3 days after PRRNT first cycle and today, 16 months after therapy, the disease seems to be in remission and the patient maintains euglycaemic state. PRRNT was well tolerated, with only hematologic grade 2 toxicity in patient 1 and mild kidney toxicity in patient 3. After the start of 177Lu-DOTA-TATE all patients achieved hypoglycaemia symptomatic control and had evident improvement of their quality of life. Three patients showed imagiological improvement suggesting reduced tumour load. (Peptide receptor radionuclide therapy with 177Lu-DOTA-TATE as a promising treatment of malignant insulinoma: a series of case reports and literature review, D. Magalhães*, I. L. Sampaio*, G. Ferreira, P. Bogalho, D. Martins-Branco, R. Santos, H. Duarte, Journal of Endocrinological Investigation 2019 Mar;42(3):249-260 *D. Magalhães and I. L. Sampaio contributed equally to this work.)
• CT-Fluoroscopy dose to the interventional radiologist has been a main concern over the last decade. The occupational dose received by an interventional radiologist (IR) during computed tomography fluoroscopy (CTF)-guided procedures was assessed to identify the most exposed areas of the body including the hands and fingers to suggest recommendations for individual monitoring and to improve radiation safety of the practice. A total of 53 CTF-guided procedures were studied. Twelve whole-body dosimeters were worn by the IR in each procedure for the assessment of the personal dose equivalent, Hp(10), on the chest, waist, and back, both over and under the lead apron, as well as the personal dose equivalent, Hp(0.07), on both arms, knees, and feet. Special gloves with casings to fit extremity dosimeters were prepared to assess Hp(0.07) to the fingers. The measured chest dose values were higher than those on the waist and back; the dominant hand or the left side was the most exposed. In general, the ring, middle, and index fingers of the dominant hand were the most exposed (maximum in the 36–39 mSv range), while wrist dose was negligible compared to finger doses. Based on the results obtained the following recommendations are suggested: protective devices (lead aprons, thyroid shield, and goggles) should be worn; Hp(10) should be assessed at the chest level both above and below the lead apron; finger doses can be measured on the basis of each middle finger; the arm closer to the beam should be monitored; and finally, a wrist dosimeter will not provide useful information (Dose to the interventional radiologist in CTF-guided procedures, J.G. Alves, S. Sarmento, J.S. Pereira, M.F. Pereira, M.J. Sousa, L. Cunha, A. Dias, A.D. Oliveira, J.V. Cardoso, L.M. Santos, J. Lencart, M. Gouvêa, J.A.M. Santos, Radiation and Environmental Biophysics (2019) 58: 373).

Scientific output in 2019

a. Peer-reviewed indexed publications (final publication date in 2019)

• Alves JG, Sarmento S, Pereira JS, Pereira MF, Sousa MJ, Cunha L, Dias A, Oliveira AD, Cardoso JV, Santos LM, Lencart J, Gouvea M, Santos JAM: Dose to the interventional radiologist in ctf-guided procedures. Radiation and environmental biophysics 2019, 58(3):373-384. Impact factor: 1.267
• Dias AG, Pinto DFS, Borges MF, Pereira MH, Santos JAM, Cunha LT, Lencart J: Optimization of skin dose using in-vivo mosfet dose measurements in bolus/non-bolus fraction ratio: A vmat and a 3dcrt study. Journal of applied clinical medical physics / American College of Medical Physics 2019, 20(2):63-70. Impact factor: 1.544
• Domingues I, Sampaio IL, Duarte H, Santos J, Abreu PH, Computer vision in esophageal cancer: a literature review, IEEE Access 7 (2019) Pages 103080 – 103094; Impact factor: 4.098
• Ghareeb F, Lencart J, Oliveira J, Santos JAM: Characterization of extrafocal dose influence on the out-of-field dose distribution by monte carlo simulations and dose measurements. Health Physics 2019, 117(5):489-503. Impact factor: 0.993
• Gouveia PB, Violante LCS, Teixeira RJV, da Silva Trindade Duarte LH: 68ga-psma uptake in prostate cancer sciatic nerve metastasis. Clinical Nuclear Medicine 2019, 44(4):e301-e302. Impact factor: 6.073
• Macedo-Silva C, Miranda-Goncalves V, Henrique R, Jeronimo C, Bravo I: The critical role of hypoxic microenvironment and epigenetic deregulation in esophageal cancer radioresistance. Genes 2019, 10(11). Impact factor: 3.331
• Magalhaes D, Sampaio IL, Ferreira G, Bogalho P, Martins-Branco D, Santos R, Duarte H: Peptide receptor radionuclide therapy with (177)lu-dota-tate as a promising treatment of malignant insulinoma: A series of case reports and literature review. J Endocrinol Invest 2019, 42(3):249-260. Impact factor: 3.166
• Marques F, Duarte H, Santos J, Domingues I, Amorim JP, Abreu PH: An iterative oversampling approach for ordinal classification. In: Proceedings of the 34th ACM/SIGAPP Symposium on Applied Computing. Limassol, Cyprus: Association for Computing Machinery; 2019: 771–774.: Impact Factor: NA
• Oliveira AC, Domingues I, Duarte H, Santos J, Abreu PH: Going back to basics on volumetric segmentation of the lungs in ct: A fully image processing based technique. In: Pattern Recognition and Image Analysis: 2019; Cham: Springer International Publishing; 2019: 322-334; Impact Factor: NA
• Oliveira J, Esposito A, Santos J: Configuration of volumetric arc radiotherapy simulations using primo software: A feasibility study. In: World Congress on Medical Physics and Biomedical Engineering 2018: 2019; Singapore: Springer Singapore; 2019: 499-503. Impact Factor: NA
• Pereira RC, Santos MS, Rodrigues PP, Abreu PH: Mnar imputation with distributed healthcare data. In: EPIA Conference on Artificial Intelligence: 2019; Cham: Springer International Publishing; 2019: 184-195. Impact factor: NA
• Santos MS, Pereira RC, Costa AF, Soares JP, Santos J, Abreu PH: Generating synthetic missing data: A review by missing mechanism. IEEE Access 2019, 7:11651-11667. Impact factor: 4.098
• Santos T, Maria do Carmo Lopes, Eduard Gershkevitshc, FilipaVinagre, David Faria, LilianaCarita, Miguel Pontes, Sandra Vieira, Esmeralda Poli, Sofia Faustino, Filipa Ribeiro, Mauro Trindade, Fernanda Ponte, Carlos Marcelino. Cláudio Batista, Susana Oliveira, Rita Figueira, Joana Lencart, Ester Gallego, Diazs Katia Jacob, Sandra Brás, Rui Pirraco, Joanna Izewska, IMRT national audit in Portugal, Physica Medica, 65 (2019)128-136: Impact factor: 2.532
• Silva G, Domingues I, Duarte H, Santos JAM: Automatic generation of lymphoma post-treatment pets using conditional-gans. In: 2019 Digital Image Computing: Techniques and Applications (DICTA): 2-4 Dec. 2019 2019; 2019: 1-6. Impact Factor: NA
• Souteiro P, Gouveia P, Ferreira G, Belo S, Costa C, Carvalho D, Duarte H, Sampaio IL: (68)ga-dotanoc and (18)f-fdg pet/ct in metastatic medullary thyroid carcinoma: Novel correlations with tumoral biomarkers. Endocrine 2019, 64(2):322-329. Impact factor: 3.296 

b. PhD thesis completed

None

c. Master thesis completed

• José Miguel Ferreira Gonçalves, Diagnostic Reference Levels (DRL’s); Nuclear Medicine; Administered Activities (AA); PET/CT; 18F-FDG; 68Ga-DOTANOC; 68Ga-PSMA, Mestrado em Física Médica da Faculdade de Ciências da Universidade do Porto; Concluído em 06-DEZ-2019; Orientadores: João António Miranda dos Santos; Coorientadores: Vera Catarina Marques Antunes
• Ana Rita Carvalho Teixeira, Clinical dosimetry and pharmacokinetic modelling of radiolabeled Sarabesin 3 with 68Ga and 177Lu: A new approach for prostate cancer theranostics, Mestrado em Física Médica da Faculdade de Ciências da Universidade do Porto; Concluído em 06-DEZ-2019; Orientadores: João António Miranda dos Santos, Mark W. Konijnenberg
• Guilherme Filipe Pinto Campos, Development of an independent MU calculation methodology for treatments with small fields, Mestrado em Física Médica da Faculdade de Ciências da Universidade do Porto; Concluído em 03-DEZ-2019; Orientadores: Anabela Gregorio Dias; Coorientadores: Ana Catarina Santos Souto
• Carlos Miguel Figueiredo de Carvalho, Integration of fMRI data in radiosurgery treatment planning of benign pathologies Mestrado em Física Médica da Faculdade de Ciências da Universidade do Porto; Concluído em 27-NOV-2019; Orientadores: Sofia Isabel Silva; Coorientadores: Sara Pinto
• Pedro Filipe Conde Andrade Silva, PET/CT radiomics em linfomas de Hodgkin, Mestrado em Tecnologias de Imagem Médica, Universidade de Aveiro, 2019; Orientador: Augusto Marques Ferreira Silva; Co-orientadores: Ângelo Paiva Oliveira, João António Miranda dos Santos
• Ana Catarina Morais Martins Teixeira, Optimização do processo de fabrico aditivo para a produção de bólus individualizados em Radioterapia Externa no cancro da mama, Mestrado em Engenharia Metalúrgica e dos Materiais, Faculdade de Engenharia da Universidade do Porto, 2019; Orientadores: Anabela Dias
• António Pedro Soares Teixeira da Rede, Influência dosimétrica dos dispositivos de imobilização na radioterapia externa, Universidade do Minho, Portugal (Licenciatura em Física), 2019; Orientadores: Luís Cunha e Anabela Dias
• Joana Santos, “The role of 18F-FDG PET/CT in staging of Breast Cancer Patients proposed to Neoadjuvant Chemotherapy: comparative analysis with breast MRI and bone scintigraphy”, MSc dissertation, Coimbra University; Co-orientação: Inês Domingues
• Ana Oliveira, “Segmentation of organs and tumors on PET and CT: tools to aid Radiotherapy planning”, MSc dissertation, Coimbra University; Co-orientação: Inês Domingues

d. Other outputs

• Analysing the Footprint of Classifiers in Overlapped and Imbalanced Contexts, Marta Mercier, Miriam S. Santos, Pedro H. Abreu, Carlos Soares, Jastin P. Soares, and Joao Santos, Advances in Intelligent Data Analysis XVII (2018) 200–212; doi: 10.1007/978-3-030-01768-2_17
• F. S. Ferreira, I. Domingues and J. Santos, “Classifying very small multi-modal data: application oesophagic early-stage cancers”, in Portuguese Conference on Pattern Recognition (RECPAD), 2019
• João A. M. Santos was president of the organizing committee of the “Congresso Nacional de Medicina Nuclear” of the Nuclear Medicine Portuguese Society (SPMN), Porto, Portugal.
• João A. M. Santos integrated the scientific committee of the “Congresso Nacional de Medicina Nuclear” of the Nuclear Medicine Portuguese Society (SPMN), Porto, Portugal.
• Vera C. M. Antunes integrated the organizing committee of the “Congresso Nacional de Medicina Nuclear” of the Nuclear Medicine Portuguese Society (SPMN), Porto, Portugal.
• Carla Capelo integrated the organizing committee of the “Congresso Nacional de Medicina Nuclear” of the Nuclear Medicine Portuguese Society (SPMN), Porto, Portugal.
• João A. M. Santos integrates the scientific committee of the Master Course in Medical Physics of the Sciences Faculty of Porto University
• Sofia Castro, Gonçalo Ferreira; Liliana Violante; Vera Antunes; Hugo Duarte, Avaliação cintigráfica pré-radioembolização hepática: 99mTc-MAA vs 166Ho-microesferas, a propósito de um caso clínico, XVII Congresso Nacional de Medicina Nuclear
• José Gonçalves, Vera Antunes, João Santos, Single centre evaluation of 18F-FDG, 68Ga-DOTANOC and 68Ga-PSMA administered activities (AA) and comparison with international guidelines, 2nd International Conference on Radiations and Applications
• Ghareeb F, Lencart J, Oliveira J, Santos JAM. PV-0477 A Monte Carlo study of collimator angle dependence of extra focal dose during VMAT. Radiotherapy and Oncology. 2019;133:S244-S5. doi: https://doi.org/10.1016/S0167-8140(19)30897-7, European Society for Radiotherapy and Oncology ESTRO 38. April 26 -30, 2019 Milan, Italy.
• Gonçalves S, Monteiro FJ, Neto R, Machado M, Lencart J, Dias AG, Produção de bólus individualizados via impressão tridimensional para Radioterapia Externa no cancro da mama, I Encontro Nacional de Jovens Investigadores (I ENJIO), Setembro 2019, Porto, Portugal.
• Dina Gonçalves, Isabel Bravo, Bárbara Barbosa, Celeste Oliveira, Digital Skills Development Assessment Among Therapeutic Radiographers, “International Conference on Medical Imaging and Radiotherapy”, Malta, 2019
• Bárbara Barbosa, Anabela Dias, Isabel Bravo, Celeste Oliveira Digital Skills for Therapy Radiographers (TR) – a document analysis “International Conference on Medical Imaging and Radiotherapy”, Malta, 2019
• Susana Gonçalves, membro da Comissão Científica e da Comissão Organizadora do Congresso Nacional da Associação Portuguesa de Radioterapeutas (CNART), Novembro de 2019, Lisboa, Portugal.
• Gonçalves S, Monteiro FJ, Neto R, Machado M, Lencart J, Dias AG, Produção de bólus individualizados via impressão tridimensional para Radioterapia Externa no cancro da mama, I Encontro Nacional de Jovens Investigadores (I ENJIO), Setembro 2019, Porto, Portugal (painel).
• Hugo Duarte, Avaliação da Resposta nas Recidivas – Em que Situações Poderá a Medicina Nuclear Complementar o Estudo Radiológico, Controvérsias e Atualidades no Cancro do Ovário – Uma Abordagem Multidisciplinar 1ª Edição, 2019 (capítulo)
• Hugo Duarte, Avaliação metabólica do tumor primário pré e pós-tratamento – deve ser considerada? XVIII Jornadas de Senologia Carvoeiro-Algarve, 11-12.10.2019 (palestra convidada)
• Joana Lencart, Reunião de follow-up do Grupo de trabalho do ensaio clínico: Stereotactic body radiotherapy for cT1c – cT3a prostate cancer with a low risk of nodal metastases (≤ 20%, Roach index): a Novalis Circle Phase II prospective randomized Trial.
• Luís Cunha, Controlo do movimento respiratório: Como o utilizar a nosso favor, Curso avançado em inovação e desenvolvimento em SBRT: da teoria à prática clínica, Congresso Nacional da Associação Portuguesa de Radioterapeutas, Lisboa, 2019
• Inês Domingues, Secretary of the presidency of APRP (Associação Portuguesa de Reconhecimento de Padrões – The Portuguese Association of Pattern Recognition)
• Inês Domingues, Membro da comissão científica: 25th Portuguese Conference on Pattern Recognition (RECPAD)
• Inês Domingues, Membro da comissão científica: XVWorkshop em Visao Computacional (WVC)
• Inês Domingues, Membro da comissão científica: International Conference in Engineering Applications (ICEA)
• Inês Domingues, Membro da comissão científica: European Conference on the Impact of AI and Robotics (ECIAIR)
• Inês Domingues, Membro da comissão científica: VII ECCOMAS Thematic Conference on Computational Vision and Medical Image Processing (VipIMAGE)
• Inês Domingues, Membro da comissão científica: 14th Iberian Conference on Information Systems and Technologies (CISTI)
• Inês Domingues, Membro da comissão científica: WorldCIST Workshop ASDACS – Applied Statistics and Data Analysis using Computer Science
• Inês Domingues, Summer school organization: VISUM – VISion Understanding and Machine intelligence summer school. Role: Finance and registrations

e. National and international collaborations

• Consórcio Europeu no projecto Safe and Free Exchange of EU Radiography Professionals across Europe (SAFE EUROPE). Bárbara Barbosa e Isabel Bravo como Manager do Work Package atribuído ao IPO.
• European Radiation Dosimetry Group – EURADOS (https://eurados.sckcen.be/).
• Stereotactic body radiotherapy for cT1c – cT3a prostate cancer with a low risk of nodal metastases (≤ 20%, Roach index): a Novalis Circle Phase II prospective randomized Trial.