Luiz Antonio Ribeiro da Rosa
National Nuclear Energy Commission
Imaging phantomDosimeterIrradiationPhysicsBiomedical engineeringThermoluminescent dosimeterAbsorbed dosePhotonDeveloped countryBeam (structure)Linear particle acceleratorAttenuationPediatricsMaterials scienceMonte Carlo methodRadiation treatment planningYoung adultAbdomenPublic healthcareNuclear medicineComputed tomographyMedicineDosimetry
Publications 27
#1Dirceu Dias Pereira (CNEN: National Nuclear Energy Commission)
#2Simone C. Cardoso (UFRJ: Federal University of Rio de Janeiro)H-Index: 8
Last. O.D. Gonçalves (UFRJ: Federal University of Rio de Janeiro)H-Index: 12
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Abstract null null We report the experimental study on the physical and radiation properties of polylactic acid polymer (PLA-C3H4O2) combined with Monte Carlo simulations for application in radiotherapy. The suitability of PLA for phantoms construction as a substitute for soft human tissue in MeV photon radiation dosimetry and therapy is discussed. The elemental composition and radiation properties are described as recommended by ICRU 44. In addition, Hounsfield unit (HU), mass attenuation coeff...
A BS TRACT Computed tomography (CT) is an indispensable imaging technique, but radiation exposure from CT scans is of concern mainly due to the potential risk of developing cancer, mainly in children. Our group recently showed that CT use has greatly increased among outpatients using the Brazilian public health system (SUS) between 2001 and 2011. Further, CT examinations among patients younger than 20 years of age represented around 13.4% of all CT examinations in SUS between 2008 and 2011. In c...
An important modality for the treatment of prostate cancer is teletherapy. The use of image-guided radiotherapy (IGRT) is a valuable tool in this treatment. This study retrospectively compared how repositioning the patient based on bone structure (B-ISO) and the prostate itself (P-ISO) affected the volumetric dose in the rectum, bladder, and clinical treatment volume (CTV). Additionally, the probability of normal tissue complication (NTCP) for the rectum was computed. We evaluated 155 cone-beam ...
#1Crystian W.C. Saraiva (CNEN: National Nuclear Energy Commission)H-Index: 2
#2Simone C. Cardoso (UFRJ: Federal University of Rio de Janeiro)H-Index: 8
Last. Luiz Antonio Ribeiro da Rosa (CNEN: National Nuclear Energy Commission)H-Index: 5
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INTRODUCTION: This study explores the possibility of a relationship between the sphericity degree of a target volume with the dose distribution. This relationship is evaluated based on the ratio isodose volume / target volume (IV/TV) and the metrics coverage, i.e., selectivity, gradient index, conformity index and mean dose when planning radiosurgery for vestibular schwannoma. METHODS: Sphericity degree (phi) was calculated for each target volume (TV) of 64 patients who underwent stereotactic ra...
#2Richard W Harbron (RVI: Royal Victoria Infirmary)H-Index: 10
Last. Lene H.S. VeigaH-Index: 17
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Abstract Objectives To evaluate the patterns and trends of diagnostic imaging examinations among outpatients of the Brazilian public healthcare system (SUS) from 2002 to 2014. Methods We collected the annual number of diagnostic imaging procedures among SUS outpatients and the number of diagnostic imaging machines (in use in Brazil and available to SUS) from an online database managed by SUS. Usage rates of procedures among SUS-dependent population were estimated using demographic data and the p...
#2Luiz Antonio Ribeiro da Rosa (CNEN: National Nuclear Energy Commission)H-Index: 5
Last. Delson Braz (UFRJ: Federal University of Rio de Janeiro)H-Index: 11
view all 4 authors...
In this work the quality of the treatment planning generated by Eclipse O commercial treatment planning system for electron beams of energy 9 and 20 MeV was verified and their accuracy in the calculation of dose distributions for several clinical situations was evaluated. Tests cases had been developed according to the Brazilian reality, having as reference the radiotherapy treatments carried out in the National Institute of the Cancer.The system developed for checking the quality of treatment p...
Computed tomography (CT) scanning is a relatively high-dose procedure which use has been rapidly increasing in many countries, although a decline has been observed recently in some developed countries. Relatively little is known about CT usage in Brazil. A recent report showed that number of CT procedures among outpatients of the Brazilian public healthcare system (SUS) tripled from 2001 to 2011 and about 13% of all CTs procedures were underwent among pediatric and young adult patients. In the p...
The aim of this work was to implement a simple algorithm to evaluate isocenter dose in a phantom using the back-projected transmitted dose acquired using an Electronic Portal Imaging Device (EPID) available in a Varian Trilogy accelerator with two nominal 6 and 10 MV photon beams. This algorithm was developed in MATLAB language, to calibrate EPID measured dose in absolute dose, using a deconvolution process, and to incorporate all scattering and attenuation contributions due to photon interactio...
While the patterns and trends of computed tomography (CT) are well documented in developed countries, relatively little is known about CT usage in developing countries, including Brazil. We evaluated CT usage among outpatients from the public healthcare system in Brazil (SUS), which is the unique healthcare provider to about 75% of the Brazilian population. We collected the annual number of CT procedures and type of CT examinations performed in SUS for the period 2001–2011. Age at examination wa...
Abstract In this work the head and neck cancer treatment of a pregnant patient was experimentally simulated. A female anthropomorphic Alderson phantom was used and the absorbed dose to the fetus was evaluated protecting the patient's abdomen with a 7 cm lead layer and using no abdomen shielding. The target volume dose was 50 Gy. The fetus doses evaluated with and without the lead shielding were, respectively, 0.52±0.039 and 0.88±0.052 cGy.
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