RESUMEN
PURPOSE: To predict patients who would benefit from adaptive radiotherapy (ART) and re-planning intervention based on machine learning from anatomical and dosimetric variations in a retrospective dataset. MATERIALS AND METHODS: 90 patients (pts) treated for head-neck cancer (H&N) formed a multicenter data-set. 41 H&N pts (45.6%) were considered for learning; 49 pts (54.4%) were used to test the tool. A homemade machine-learning classifier was developed to analyze volume and dose variations of parotid glands (PG). Using deformable image registration (DIR) and GPU, patients' conditions were analyzed automatically. Support Vector Machines (SVM) was used for time-series evaluation. "Inadequate" class identified patients that might benefit from replanning. Double-blind evaluation by two radiation oncologists (ROs) was carried out to validate day/week selected for re-planning by the classifier. RESULTS: The cohort was affected by PG mean reduction of 23.7±8.8%. During the first 3weeks, 86.7% cases show PG deformation aligned with predefined tolerance, thus not requiring re-planning. From 4th week, an increased number of pts would potentially benefit from re-planning: a mean of 58% of cases, with an inter-center variability of 8.3%, showed "inadequate" conditions. 11% of cases showed "bias" due to DIR and script failure; 6% showed "warning" output due to potential positioning issues. Comparing re-planning suggested by tool with recommended by ROs, the 4th week seems the most favorable time in 70% cases. CONCLUSIONS: SVM and decision-making tool was applied to overcome ART challenges. Pts would benefit from ART and ideal time for re-planning intervention was identified in this retrospective analysis.
Asunto(s)
Aprendizaje Automático , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia Asistida por Computador/métodos , Estudios de Cohortes , Humanos , Reproducibilidad de los Resultados , Estudios RetrospectivosRESUMEN
The eye lens is considered to be among the most radiosensitive human tissues. Brain CT scans may unnecessarily expose it to radiation even if the area of clinical interest is far from the eyes. The aim of this study is to implement a bismuth eye lens shielding system for Head-CT acquisitions in these cases. The study is focused on the assessment of the dosimetric characteristics of the shielding system as well as on its effect on image quality. The shielding system was tested in two set-ups which differ for distance ("contact" and "4 cm" Set up respectively). Scans were performed on a CTDI phantom and an anthropomorphic phantom. A reference set up without shielding system was acquired to establish a baseline. Image quality was assessed by signal (not HU converted), noise and contrast-to-noise ratio (CNR) evaluation. The overall dose reduction was evaluated by measuring the CTDIvol while the eye lens dose reduction was assessed by placing thermoluminescent dosimeters (TLDs) on an anthropomorphic phantom. The image quality analysis exhibits the presence of an artefact that mildly increases the CT number up to 3 cm below the shielding system. Below the artefact, the difference of the Signal and the CNR are negligible between the three different set-ups. Regarding the CTDI, the analysis demonstrates a decrease by almost 12 % (in the "contact" set-up) and 9 % (in the "4 cm" set-up). TLD measurements exhibit an eye lens dose reduction by 28.5 ± 5 and 21.1 ± 5 % respectively at the "contact" and the "4 cm" distance. No relevant artefact was found and image quality was not affected by the shielding system. Significant dose reductions were measured. These features make the shielding set-up useful for clinical implementation in both studied positions.
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Absorción de Radiación , Bismuto/química , Cristalino/efectos de la radiación , Protección Radiológica , Cabeza , Humanos , Fantasmas de Imagen , Dosimetría Termoluminiscente , Tomografía Computarizada por Rayos XRESUMEN
UNLABELLED: Fenoldopam is a selective DA1 agonist with potential nephroprotective capabilities. The aim of this study was to compare the nephroprotective effect of fenoldopam and dopamine during general anesthesia for living donor kidney transplantation. METHODS: Forty donors enrolled in the study received a similar anesthetic and fluid protocol. The patients were randomly divided into group F (receiving 0.1 mg*kg-1*min-1 fenoldopam) versus group D (receiving "renal dose" 3 mg*kg-1*min-1 dopamine). The mean volume of infused fluids, diuresis, and urinary electrolytes (Na, K, Cl) at infusion start and 120 minutes later were studied. RESULTS: Anthropometric parameters, administered anesthetics, mean infused volume, and urine outputs, did not show significant differences between the groups. Statistically significant differences were observed for urinary excretion of sodium, potassium, and chloride after 120 minutes of continuous fenoldopam infusion, with significant variations within groups for sodium only. CONCLUSIONS: Fenoldopam compared with dopamine resulted in better nephroprotective effects. No adverse events were recorded, and side effects were minimal. Further studies are necessary to evaluate these data.
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Dopaminérgicos/uso terapéutico , Dopamina/uso terapéutico , Fenoldopam/uso terapéutico , Trasplante de Riñón/fisiología , Donadores Vivos , Adulto , Fenoldopam/administración & dosificación , Humanos , Infusiones Intravenosas , Persona de Mediana EdadRESUMEN
Transforming growth factor-beta (TGF-beta) is involved in several autoimmune neurological diseases. It is still unclear whether its local action can be pro-inflammatory or anti-inflammatory in the muscle tissue, because of the few reports on this subject. We have previously shown that human myoblasts secrete interleukin-6 (IL-6) when stimulated with inflammatory cytokine such as interleukin-1beta (IL-1beta) or tumor necrosis factor alpha. In the present report, we show that TGF-beta1 can induce IL-6 production; moreover, costimulation or short term pre-incubation with TGF-beta1 increases IL-1beta effect, while a longer incubation inhibits its action.