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1.
Ann Med Surg (Lond) ; 86(5): 2474-2480, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38694305

RESUMO

Introduction: In locally advanced rectal cancers (LARC), tumour node metastasis (TNM) staging is far from optimal. The authors aimed to investigate the value of previously described circulating biomarkers as predictors of prognosis. Methods: Retrospective analysis of 245 LARC patients diagnosed between January 2010 and December 2022, who underwent neoadjuvant chemoradiotherapy and surgery at two centres. A Cox regression and Kaplan-Meier analysis were performed. Results: Post-treatment platelet-to-lymphocyte ratio (PLR) predicted pathological complete response. The neutrophil-to-lymphocyte ratio (NLR) in two timepoints of the treatment significantly predicted overall survival, whereas the platelet-neutrophil (PN) index significantly predicted disease-free survival. In pathological stage II, the PN index predicted patients with a higher risk of disease-free survival. Conclusion: Blood parameters might allow the definition of subgroups of risk beyond TNM for the application of different therapeutic strategies.

2.
Pharmaceuticals (Basel) ; 16(3)2023 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-36986526

RESUMO

"Watch and wait" is becoming a common treatment option for patients with locally advanced rectal cancer (LARC) submitted to neoadjuvant treatment. However, currently, no clinical modality has an acceptable accuracy for predicting pathological complete response (pCR). The aim of this study was to assess the clinical utility of circulating tumor DNA (ctDNA) in predicting the response and prognosis in these patients. We prospectively enrolled a cohort of three Iberian centers between January 2020 and December 2021 and performed an analysis on the association of ctDNA with the main response outcomes and disease-free survival (DFS). The rate of pCR in the total sample was 15.3%. A total of 24 plasma samples from 18 patients were analyzed by next-generation sequencing. At baseline, mutations were detected in 38.9%, with the most common being TP53 and KRAS. Combination of either positive magnetic resonance imaging (MRI) extramural venous invasion (mrEMVI) and ctDNA increased the risk of poor response (p = 0.021). Also, patients with two mutations vs. those with fewer than two mutations had a worse DFS (p = 0.005). Although these results should be read carefully due to sample size, this study suggests that baseline ctDNA combined with mrEMVI could potentially help to predict the response and baseline ctDNA number of mutations might allow the discrimination of groups with different DFS. Further studies are needed to clarify the role of ctDNA as an independent tool in the selection and management of LARC patients.

3.
Radiat Prot Dosimetry ; 199(6): 552-563, 2023 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-36916121

RESUMO

PET cyclotrons are widely used for producing medical diagnostic radionuclides. The main radionuclide produced in these facilities is the 18F, which is obtained from the [18O (p,n)18F] reaction when 18O-enriched water is bombarded with the proton beams. This work aimed to estimate the radiation source term from the bombardment of an 18O-enriched water target with protons of 16.5 MeV to determine the radiation neutron field around the accelerator.


Assuntos
Ciclotrons , Prótons , Isótopos de Oxigênio , Método de Monte Carlo , Água
4.
Appl Radiat Isot ; 194: 110685, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36758323

RESUMO

Individual monitoring can provide an estimate of the radioactivity present in the body of the exposed individuals. Periodic monitoring of occupationally exposed individuals is of great importance in case of accidental incorporation. Computational phantoms and Monte Carlo codes are often used to complement the calibration method of counting systems in internal dosimetry. Here, counting efficiency (CE) factors for a WBC system were calculated using MC simulations. The WBC system with a NaI(Tl) detector and the BOMAB phantom was modeled using three MC codes. After validation, the models were used to obtain CE values for a wide range of energies, and a CE curve was generated for the WBC system. To estimate the effects of anatomical differences on the measurement process, two anthropomorphic voxel phantoms were modeled using the VMC code. For the detector position with the highest CE value, the differences when comparing BOMAB results with the MaMP and Yale results were (-1 ± 6)% and (-1 ± 3)%, respectively. The results confirm that the use of the BOMAB phantom is a good approach for the calibration of the whole-body counter system. Measurements should be made at detector position with the highest CE values, and it is recommended to use the mean Monte Carlo CE values calculated in this work.


Assuntos
Radiometria , Contagem Corporal Total , Humanos , Contagem Corporal Total/métodos , Simulação por Computador , Radiometria/métodos , Imagens de Fantasmas , Método de Monte Carlo
5.
Appl Radiat Isot ; 191: 110526, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36401987

RESUMO

The radiopharmaceuticals most commonly used in nuclear medicine are 18F-FDG and 99mTc-DMSA, both of which are administered to paediatric and adult patients using the same time activity coefficient. However, the IAEA recommends specific paediatric dosimetry. The aim of this work (TW) was to estimate the absorbed dose for 18F-FDG and 99mTc-DMSA using two paediatric voxel phantoms (Baby and Child) by Monte Carlo techniques. Biokinetic data for both radiopharmaceuticals were obtained from ICRP 128. In addition, the new time-integrated activity coefficient (TIAC) values from a recent publication were examined for the following organs: Brain, urinary bladder wall, liver, heart wall, and lung. The absorbed dose per injected activity (AD/IA) and effective dose per injected activity (E/IA) values were calculated for both phantoms and the results were compared with simulated data of paediatric phantoms from ICRP 128, MIRDcalc software and available literature. Regarding AD/IA in organs, differences of up to 61% and 115% were found for the Baby phantom and 120% and 167% for the Child phantom using 18F-FDG and 99mTc-DMSA, respectively. For FDG using the new TIAC, a maximum difference of 244% was observed. For E/IA, the maximum differences were 27% and 31% for the Baby and Child phantoms, respectively, for FDG and DSMA. In this study, new dosimetric data were calculated using Baby and Child phantoms and the newly recommended TIAC.


Assuntos
Fluordesoxiglucose F18 , Compostos Radiofarmacêuticos , Adulto , Lactente , Humanos , Criança , Método de Monte Carlo , Imagens de Fantasmas , Succímero
6.
Cir Cir ; 90(S2): 36-41, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36480751

RESUMO

BACKGROUND: Gastric cancer is the fourth cancer most common in the world and the second cause of cancer-related deaths. Perioperative chemotherapy may reduce tumor burden and decrease lymph node invasion, improving R0 resections rates. On the other hand, administered before surgery, chemotherapy may cause fibrosis and tissue edema, with potential increase of surgical difficulty and in the number of post-operative complications. Therefore, we aim to investigate the effect of perioperative chemotherapy for tumor burden and metastatic lymph nodes of gastric cancer. METHODS: Retrospective analysis of all patients submitted to perioperative chemotherapy and surgery, between January 2010 and June 2020, which showed lymph node regression and tumor regression (Becker's classification). RESULTS: A total of 112 patients with an average age of 61.9 years were analyzed. About 90.2% completed three cycles of perioperative chemotherapy. Good tumor response to chemotherapy (<10% residual tumor) was achieved in 21.3% of patients. Only three patients obtained a complete pathological response. A median lymph node response of 33.3% was achieved in our series. CONCLUSION: Despite no evident outstanding regression rate was observed, perioperative chemotherapy seems to be useful in obtaining a R0 resection in gastric cancer, even in advanced gastric cancer.


INTRODUCCIÓN: El cáncer de estómago es el cuarto tipo de cáncer más común y la segunda causa de muerte relacionada con el cáncer. La quimioterapia perioperatoria puede reducir la carga tumoral y disminuir la invasión de los ganglios linfáticos. Por otro lado, administrada antes de la cirugía, la quimioterapia puede causar fibrosis y edema tisular, aumentando potencialmente la dificultad quirúrgica y el número de complicaciones posoperatorias. Nuestro objetivo es investigar el efecto de la quimioterapia perioperatoria sobre la carga tumoral y los ganglios metastásicos en el cáncer gástrico. MÉTODOS: Análisis retrospectivo de todos los pacientes sometidos a quimioterapia y cirugía, entre enero de 2010 y junio de 2020. RESULTADOS: Se analizaron 112 pacientes con una edad media de 61.9 años. El 90.2% completó 3 ciclos de quimioterapia perioperatoria. Se logró una buena respuesta tumoral a la quimioterapia (< 10% de tumor residual) en el 21.3% de los pacientes. Tres pacientes lograron una respuesta patológica completa. En nuestra serie se logró una mediana de respuesta de los ganglios linfáticos del 33.3%. CONCLUSIÓN: Aunque no se observó una tasa de regresión manifiesta, la quimioterapia perioperatoria parece ser útil para lograr una resección R0 en el cáncer gástrico, incluso en el cáncer gástrico avanzado.


Assuntos
Neoplasias Gástricas , Humanos , Pessoa de Meia-Idade , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/cirurgia , Estudos Retrospectivos
7.
Langenbecks Arch Surg ; 407(7): 2703-2714, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35932298

RESUMO

BACKGROUND: Regarding the assessment of patients' immune and nutritional status, prognostic nutritional index (PNI) has been reported as a predictive marker for surgical outcomes in various types of cancer. The aim of our study was to evaluate the effect of PNI in prognosis of gastric cancer patients submitted to curative-intent resectional surgery. MATERIAL AND METHODS: A retrospective analysis with 637 gastric cancer cases submitted to curative-intent surgery, between 2010 and 2017, in an upper GI surgery unit. We analyzed 396 patients that met the inclusion criteria for this study. The median follow-up was 37 (0-113) months. RESULTS: According to Youden's method, the optimal PNI cutoff for OS was 41.625 (sensitivity 89.3% and specificity 41.3%). OS was significantly shorter in the lower-PNI group of patients when compared to the higher-PNI group (40.26 vs 77.49 months; p < 0.001). Higher PNI had a positive impact on OS in univariable analysis. When adjusted to pStage, higher PNI was still significantly associated with better OS (HR 0.405; CI 95% 0.253-0.649; p < 0.001). Regarding DFS, higher PNI was associated with better DFS (HR 0.421; CI 95% 0.218-0.815; p = 0.010). Higher-PNI group had a protective effect regarding postoperative morbidity and mortality. CONCLUSIONS: In this cohort, PNI was disclosed to significantly impact GC patients' OS and DFS, including in multivariable analysis when adjusting for classical prognostic features. PNI can be used to predict patients at increased risk of postoperative morbidity and mortality. This index may be of use in identifying candidate patients who would benefit from perioperative nutritional support to improve surgical outcomes.


Assuntos
Avaliação Nutricional , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/cirurgia , Gastrectomia/efeitos adversos , Prognóstico , Estudos Retrospectivos , Estado Nutricional
8.
Porto Biomed J ; 7(6): e180, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37152082

RESUMO

Background: Perioperative chemotherapy (PeriCh) is the current standard of care for stage II/III gastric cancer tumors in Europe. However, when it concerns patients who endure complications during PeriCh it is unclear if it increases the risk of postoperative complications and other poorer surgical outcomes. We aim to demonstrate if there is an association between having complications during PeriCh and postoperative complications and histopathological response. Methods: We conducted a retrospective, transversal, and observational study, including all patients with diagnosed gastric cancer who underwent PeriCh followed by surgical resection during the period of eight years. Results: We included 80 patients with a median age of 64.0years (min 24, max 78). Eighty-eight-point eight percent ended the chemotherapy regime proposed, with a median duration of 42 days, and were also submitted to gastric resection: 58.8% total gastrectomy and 41.2% distal gastrectomy. Twelve-point five percent of the patients had no complications during the PeriCh period and 16.3% had >2 complications. Twenty-five percent of patients had a histological response of <10% of tumor burden, but in 41.3% only regression of <50% could be obtained. No significant association was found between complications during PeriCh and adverse surgical outcomes (P = .497). Patients with complications during PeriCh had slightly higher median time difference from end of PeriCh until surgery, but with no statistical significance (P = .575). Conclusions: In our sample, the existence of association between complications during PeriCh and postoperative complications or histological response was not demonstrated.

9.
Front Oncol ; 11: 766407, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34900715

RESUMO

Interstitial brachytherapy (BT) is generally used for the treatment of well-confined solid tumors. One example of this is in the treatment of prostate tumors by permanent placement of radioactive seeds within the prostate gland, where low doses of radiation are delivered for several months. However, successful implementation of this technique is hampered due to several posttreatment adverse effects or symptoms and operational and logistical complications associated with it. Recently, with the advancements in nanotechnology, radioactive nanoparticles (radio-NPs) functionalized with tumor-specific biomolecules, injected intratumorally, have been reported as an alternative to seed-based BT. Successful treatment of solid tumors using radio-NPs has been reported in several preclinical studies, on both mice and canine models. In this article, we review the recent advancements in the synthesis and use of radio-NPs as a substitute to seed-based BT. Here, we discuss the limitations of current seed-based BT and advantages of radio-NPs for BT applications. Recent progress on the types of radio-NPs, their features, synthesis methods, and delivery techniques are discussed. The last part of the review focuses on the currently used dosimetry protocols and studies on the dosimetry of nanobrachytherapy applications using radio-NPs. The current challenges and future research directions on the role of radio-NPs in BT treatments are also discussed.

10.
Future Oncol ; 17(35): 4947-4957, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34734533

RESUMO

Aims: To investigate the value of previously described pretreatment hematological and biochemical biomarkers as predictors of pathological response. Methods: The authors performed a retrospective analysis of 191 patients with locally advanced rectal cancer who underwent long-course neoadjuvant chemoradiotherapy at two Portuguese centers. The authors performed logistic regression analysis to search for predictive markers of pathological complete and good response. Results: High platelet-neutrophil index (p = 0.042) and clinical tumor stage >2 (p = 0.015) were predictive of poor response. None of the analyzed biomarkers predicted pathological complete response in this study. Conclusion: A high platelet-neutrophil index before neoadjuvant chemoradiotherapy could help predict poorer pathological response in patients with locally advanced rectal cancer. However, no other blood biomarker predicted incomplete or poor response in this study.


Assuntos
Biomarcadores Tumorais/sangue , Neoplasias Retais/sangue , Neoplasias Retais/diagnóstico , Quimiorradioterapia , Terapia Combinada , Feminino , Humanos , Estimativa de Kaplan-Meier , Contagem de Leucócitos , Contagem de Linfócitos , Masculino , Monócitos , Terapia Neoadjuvante , Estadiamento de Neoplasias , Neutrófilos , Razão de Chances , Contagem de Plaquetas , Prognóstico , Neoplasias Retais/mortalidade , Neoplasias Retais/terapia , Resultado do Tratamento
11.
Appl Radiat Isot ; 172: 109666, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33773203

RESUMO

Irradiation of tumor cell lines is a useful way to investigate the effects of ionizing radiation on biological molecules. We designed an easy and reproducible approach for in vitro experimental high dose rate brachytherapy, which was simulated by a Monte Carlo code and dosimetrically characterized by experimental methods to evaluate the correspondence between planned doses and doses absorbed by the cells. This approach is an acrylic platform containing T25 tissue culture flasks and multiwell tissue culture plates. It allows nine parallel needles carrying an 192Ir source to irradiate the adherent cells. The whole system composed of the acrylic platform, tissue culture flasks and 192Ir source tracking was simulated by the Monte Carlo N-Particle transport code (MCNPX). Dosimetric measurements were taken by well ionization chamber and radiochromic films. There was a slight difference, averaging from 2% to 7%, between the MCNPX results and film dosimetry results regarding uniform radiation created by the source arrangement. The results showed different values for planned and measured doses in each cell culture plate, which was attributed to the non-equivalent water material used and to the lack of full scattering coming from the top of the platform. This last contribution was different for each tissue culture plate and an individual dose correction factor was calculated. The dose correction factor must be applied to match the planned dose and the actual doses absorbed by the cells. The designed approach is an efficient tool for in vitro brachytherapy experiments for most commercial cell culture plates.


Assuntos
Braquiterapia/métodos , Dosagem Radioterapêutica , Humanos , Técnicas In Vitro , Método de Monte Carlo
12.
Phys Med Biol ; 66(4): 045016, 2021 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-33561008

RESUMO

PURPOSE: Nanoparticles (NPs) with radioactive atoms incorporated within the structure of the NP or bound to its surface, functionalized with biomolecules are reported as an alternative to low-dose-rate seed-based brachytherapy. In this study, authors report a mathematical dosimetric study on low-dose rate brachytherapy using radioactive NPs. METHOD: Single-cell dosimetry was performed by calculating cellular S-values for spherical cell model using Au-198, Pd-103 and Sm-153 NPs. The cell survival and tumor volume versus time curves were calculated and compared to the experimental studies on radiotherapeutic efficiency of radioactive NPs published in the literature. Finally, the radiotherapeutic efficiency of Au-198, Pd-103 and Sm-153 NPs was tested for variable: administered radioactivity, tumor volume and tumor cell type. RESULT: At the cellular level Sm-153 presented the highest S-value, followed by Pd-103 and Au-198. The calculated cell survival and tumor volume curves match very well with the published experimental results. It was found that Au-198 and Sm-153 can effectively treat highly aggressive, large tumor volumes with low radioactivity. CONCLUSION: The accurate knowledge of uptake rate, washout rate of NPs, radio-sensitivity and tumor repopulation rate is important for the calculation of cell survival curves. Self-absorption of emitted radiation and dose enhancement due to AuNPs must be considered in the calculations. Selection of radionuclide for radioactive NP must consider size of tumor, repopulation rate and radiosensitivity of tumor cells. Au-198 NPs functionalized with Mangiferin are a suitable choice for treating large, radioresistant and rapidly growing tumors.


Assuntos
Braquiterapia/métodos , Simulação por Computador , Doses de Radiação , Radioisótopos/química , Radioisótopos/uso terapêutico , Radioisótopos de Ouro/química , Radioisótopos de Ouro/uso terapêutico , Método de Monte Carlo , Neoplasias/radioterapia , Paládio/química , Paládio/uso terapêutico , Radiometria , Dosagem Radioterapêutica , Samário/química , Samário/uso terapêutico
13.
Phys Med ; 80: 363-372, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33285337

RESUMO

The effects of low energy electrons in biological tissues have proved to lead to severe damages at the cellular and sub-cellular level. It is due to an increase in the relative biological effectiveness (RBE) of these electrons with a decrease in their penetration range. That is, lower the range higher will be its RBE.Therefore, accurate determination of low energy electron range becomes a key issue for radiation dosimetry. This work reports on in-water electron tracks evaluated at low kinetic energy (1-50 keV) using isotropic mono-energetic point source approach suitably implemented by different general-purpose Monte Carlo codes. For this aim, simulations were performed using PENELOPE, EGSnrc, MCNP6, FLUKA and Geant4-DNA Monte Carlo codes to obtain the particle range, R,R90,R50. Finally, evaluation of dose point kernel (DPK), as used for internal dosimetry, was carried out as an application example. Scaled dose point kernels (sDPK) were estimated for a range of mono-energetic low energy electron sources. The non-negligible differences among the calculated sDPK using different codes were obtained for energy electrons up to 5 keV. It was also observed that differences of in-water range for low-energy electrons, due to the different general-purpose Monte Carlo codes, affected the DPKs used for dosimetry by convolution approach. Finally, the 3D dosimetry was found to be almost not affected at macroscopic clinical scale, whereas non-negligible differences appeared at the microscopic level. Hence, a thorough validation of the used sDPKs have to be performed before they could be used in applications to derive any conclusions.


Assuntos
Elétrons , Método de Monte Carlo , Água , Simulação por Computador , Radiometria , Eficiência Biológica Relativa
14.
Appl Radiat Isot ; 166: 109302, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32795694

RESUMO

This work focuses on the calculation of S-values and radial energy profiles for radionuclides emitting high (Y-90, Sr-89), medium (Re-186, Sm-153) and low-energy (Er-169, Lu-177) ß-particles, Auger electrons (In-111, Ga-67, I-123) and α-particles (At-211, Ac-225). Simulations were performed using the EGSnrc and GEANT4-DNA Monte Carlo (MC) codes for a spherical cell geometry. S-values were computed using decay spectra available in literature for Tc-99m and In-111. To investigate the effect on S-value when the same emission spectrum is used in two different MC codes. Internal modules of the MC codes were used to simulate the decay of other radionuclides mentioned above. Radial energy profiles for uniformly distributed radioactive sources in the cell nucleus and cytoplasm were calculated and results were compared with the literature. For S-values calculated using the same emission spectrum, the results showed good agreement with each other and with the literature. Whereas, the S-values calculated using the internal decay data of the MC codes, for instance, for Ga-67 and Y-90, showed discrepancies up to 40%. Radial energy profiles were also different from those reported in the literature. Our results show that well validated radiation emission spectra must be used for such calculations and internal decay spectra of MC codes should be used with caution. The normalized probability density functions must be used to sample points uniformly into spherical volumes and the methodology proposed here can be used to correctly determine radial energy profiles.

15.
IDCases ; 20: e00745, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32322504

RESUMO

Ceftazidime/avibactam combines ceftazidime with a new beta-lactam that successfully that inhibits Amber Class A and D carbapenemases. We report a clinical case of a 61 year-old man with a carbapenemase-producing Klebsiella pneumoniae intra-abdominal infection after an elective abdominal hernia repair. The infection was successfully managed with multiple abdominal surgeries, drainage and combined antibiotic therapy with ceftazidime/avibactam plus tigecycline.

16.
Biomed Phys Eng Express ; 6(1): 015035, 2020 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-33438623

RESUMO

This study reports the comparison between two dose calculation algorithms, Acuros XB 13.5 (AXB) and Analytical Anisotropic Algorithm (AAA) against Monte Carlo (MC) simulations for 3D-Conformal Radiation Therapy (3D-CRT) using a female pelvic rando phantom. 3D-CRT treatment plans were generated on the CT images of rando phantom using AXB and AAA with Source to Axis Distance (SAD) technique. Doses obtained using two algorithms and MC results were compared using MATLAB based software CERR. In house MATLAB code was developed to calculate the gamma dose distribution comparison in terms of dose difference (DD) and distance to agreement distribution (DTA). The results showed that the Dmean in the PTV TOTAL (PTV) volume for AXB and AAA was equal to the mean dose calculated by MC simulations. The gamma passing rates for AXB were more accurate in comparison to AAA with reference to MC for PTV, Bladder and Femoral Heads region. After analysing the dose comparison specially for the PTV, femoral heads, also the analysis of dose volume histogram (DVH) and gamma dose distribution comparison for PTV, femoral heads and bladder, it can be concluded that AXB is more accurate in comparison to AAA. It can be said that AXB is well suited for dose calculation in clinical setup when compared to MC calculations.


Assuntos
Algoritmos , Anisotropia , Método de Monte Carlo , Pelve/diagnóstico por imagem , Imagens de Fantasmas , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Simulação por Computador , Feminino , Humanos , Dosagem Radioterapêutica , Software
17.
Br J Radiol ; 90(1080): 20170187, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28937271

RESUMO

OBJECTIVE: The aim of this work was to simulate a 6MV conventional breast 3D conformational radiation therapy (3D-CRT) with physical wedges (50 Gy/25#) in the left breast, calculate the mean absorbed dose in the body organs using robust models and computational tools and estimate the secondary cancer-incidence risk to the Brazilian population. METHODS: The VW female phantom was used in the simulations. Planning target volume (PTV) was defined in the left breast. The 6MV parallel-opposed fields breast-radiotherapy (RT) protocol was simulated with MCNPx code. The absorbed doses were evaluated in all the organs. The secondary cancer-incidence risk induced by radiotherapy was calculated for different age groups according to the BEIR VII methodology. RESULTS: RT quality indexes indicated that the protocol was properly simulated. Significant absorbed dose values in red bone marrow, RBM (0.8 Gy) and stomach (0.6 Gy) were observed. The contralateral breast presented the highest risk of incidence of a secondary cancer followed by leukaemia, lung and stomach. The risk of a secondary cancer-incidence by breast-RT, for the Brazilian population, ranged between 2.2-1.7% and 0.6-0.4%. CONCLUSION: RBM and stomach, usually not considered as OAR, presented high second cancer incidence risks of 0.5-0.3% and 0.4-0.1%, respectively. This study may be helpful for breast-RT risk/benefit assessment. Advances in knowledge: MCNPX-dosimetry was able to provide the scatter radiation and dose for all body organs in conventional breast-RT. It was found a relevant risk up to 2.2% of induced-cancer from breast-RT, considering the whole thorax organs and Brazilian cancer-incidence.


Assuntos
Neoplasias Induzidas por Radiação/etiologia , Segunda Neoplasia Primária/etiologia , Neoplasias Unilaterais da Mama/radioterapia , Feminino , Humanos , Imagens de Fantasmas , Doses de Radiação , Radiometria , Dosagem Radioterapêutica , Radioterapia Conformacional/efeitos adversos , Radioterapia Conformacional/métodos , Medição de Risco , Fatores de Risco
19.
Braz. J. Pharm. Sci. (Online) ; 53(1): e16092, 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-839463

RESUMO

ABSTRACT The aim of this study was to create and test a new mice 3D-voxel phantom named DM_BRA for mice and human first-estimation radiopharmaceutical dosimetry. Previously, the article reviews the state-of-art in animal model development. Images from Digimouse CT database were used in the segmentation and on the generation of the voxelized phantom. Simulations for validation of the DM_BRA model was performed at 0.015, 0.1, 0.5, 1 and 4 MeV photons with heart-source. Specific Absorbed Fractions (SAF) data were compared with literature data. The organ masses of DM_BRA correlated well with existing models based on the same dataset; however, few small organ masses hold significant variations. The SAF data in most simulated cases were statistically equal to a significant level of 0.01 to the reference data.


Assuntos
Alfabetização Digital , Dosimetria/análise , Camundongos/classificação , Radiometria/métodos
20.
Acta Med Port ; 29(2): 107-13, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27234950

RESUMO

INTRODUCTION: The disruption of esophageal motility that characterizes achalasia typically provokes dysphagia, pain, loss of weight and malnutrition. Therefore, patients frequently report a reduction in quality of life and negative emotional states. Laparoscopic Heller myotomy proved to be an effective therapy, enabling the resumption of good quality of life. MATERIAL AND METHODS: The authors studied 45 patients previously submitted to laparoscopic Heller myotomy. Postoperative evaluation was performed using a customized version of the achalasia disease-specific quality of life questionnaire. Quality of life and the presence of depressive and anxiety symptoms were assessed using the Portuguese versions of the Medical Outcomes Study SF-36 and the Hospital Anxiety and Depression Scale. RESULTS: Thirty-one patients responded to the survey. Dysphagia was the main clinical symptom before surgery. A clear improvement in dysphagia, regurgitation, pain and weight loss was found after surgery (p < 0.001). The Mental Health domain of SF-36 presented a Pearson correlation coefficient of -0.689 with HADS-D and of -0.557 with HADS-A (p < 0.001 and p = 0.002, respectively). CONCLUSION: This study demonstrates that the Heller myotomy is associated with a good quality of life in patients with achalasia and strengthens the evidence that this is a safe and reliable procedure.


Introdução: A interrupção da motilidade esofágica que caracteriza a acalásia provoca disfagia, dor, perda de peso e desnutrição. Portanto, estes doentes referem uma redução na qualidade de vida e apresentam estados emocionais negativos. Procedimentos cirúrgicos, como a miotomia de Heller, têm-se revelado eficazes, permitindo retornar a uma qualidade de vida melhor. Material e Métodos: Foram incluídos no presente estudo 45 pacientes submetidos a miotomia de Heller. A avaliação pós-operatória foi realizada usando uma versão modificada do questionário de Qualidade de Vida Específico para a Acalasia. A qualidade de vida e a presença de sintomas psicológicos foram avaliados utilizando a versão portuguesa do Medical Outcomes Study SF-36 e a Escala de Ansiedade e Depressão Hospitalar. Resultados: Um total de 31 doentes (69%) foi avaliado, média de idades de 53 anos (18). A disfagia foi o principal sintoma clínico. Uma clara melhoria da disfagia, regurgitação, dor e perda de peso foi evidenciada após a cirurgia (p < 0,001). O domínio da saúde mental do SF-36 apresentou um coeficiente de correlação de Pearson de -0,689 com HADS -D e de -0,557 com HADS-A (p < 0,001 e p = 0,002, respetivamente). Conclusão: Este estudo demonstra que a miotomia de Heller se associa a uma boa qualidade de vida nos doentes com acalásia e reforça a ideia de que este é um procedimento seguro e eficaz.


Assuntos
Acalasia Esofágica/cirurgia , Laparoscopia , Satisfação do Paciente , Qualidade de Vida , Ansiedade/etiologia , Estudos Transversais , Depressão/etiologia , Autoavaliação Diagnóstica , Procedimentos Cirúrgicos do Sistema Digestório/métodos , Acalasia Esofágica/complicações , Acalasia Esofágica/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
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