Unusual Magnetic Hysteresis and Transition between Vortex and Double Pole States Arising from Interlayer Coupling in Diamond-Shaped Nanostructures.

Controlling the magnetic ground states at the nanoscale is a long-standing basic research problem and an important issue in magnetic storage technologies. Here, we designed a nanostructured material that exhibits very unusual hysteresis loops due to a transition between vortex and double pole states. Arrays of 700 nm diamond-shaped nanodots consisting of Py(30 nm)/Ru(tRu)/Py(30 nm) (Py, permalloy (Ni80Fe20)) trilayers were fabricated by interference lithography and e-beam evaporation. We show that varying the Ru interlayer spacer thickness (tRu) governs the interaction between the Py layers. We found this interaction mainly mediated by two mechanisms: magnetostatic interaction that favors antiparallel (antiferromagnetic, AFM) alignment of the Py layers and exchange interaction that oscillates between ferromagnetic (FM) and AFM couplings. For a certain range of Ru thicknesses, FM coupling dominates and forms magnetic vortices in the upper and lower Py layers. For Ru thicknesses at which AFM coupling dominates, the magnetic state in remanence is a double pole structure. Our results showed that the interlayer exchange coupling interaction remains finite even at 4 nm Ru thickness. The magnetic states in remanence, observed by magnetic force microscopy (MFM), are in good agreement with corresponding hysteresis loops obtained by the magneto-optic Kerr effect (MOKE) and micromagnetic simulations.

18F-FDG PET/CT in lung cancer. The added value of quantification / PET/TC con 18F-FDG en el cáncer de pulmón. Valor adicional de la cuantificación

Objective. To test a software application for the quantification of metabolic heterogeneity and to evaluate its superiority in relation to visual interpretation. To investigate if a quantitative analysis adds information to the interpretation of 18F-FDG-PET/CT. Material and methods. The study analyzed 215 patients with a 18F-FDG-PET/CT done for the initial staging of lung cancer between March 2011 and December 2015. The study included 57 (26.5%) women and 158 (73.5%) men, with ages ranging from 34 to 88 years (mean±SD: 67.23±10.04). There were 82 surgical stages (I, II, IIIA), and 133 non-surgical stages (IIIB, IV). The primary tumour was analyzed quantitatively by obtaining the following parameters: SUVmax, metabolic active tumour volume (MATV), total lesion glycolysis (TLG), and the entropy heterogeneity index (ET). Heterogeneity was assessed visually. Death dates and/or the follow-up time were registered, ranging from 0.70 to 67.60 months (mean±SD: 23.20±17.68). Results. In multivariate analysis, ET emerged as a better predictor of survival than visual analysis of heterogeneity that was not statistically significant. The C-index determination demonstrated that all quantitative parameters were statistically-significant predictors of survival. Cut-offs were obtained in order to compare survival times. A multivariate analysis was performed. In the total population, the best predictor was the TNM stage, but MATV, ET, and male gender were statistically significant and independent predictors of survival. In stages without surgical indication, the best predictor was the TNM stage, but the MATV and male gender were statistically significant and independent predictors of survival. In the surgical stages, ET was the only statistically significant and independent predictor of survival. Conclusions. Quantification adds prognostic information to the visual analysis of 18F-FDG-PET/CT (AU)

Objetivo. Valorar un software para cuantificar la heterogeneidad metabólica e investigar su superioridad en relación con la interpretación visual. Analizar si el análisis cuantitativo ofrece información adicional en la interpretación de los estudios 18F-FDG-PET/TC. Material y métodos. Se valoraron retrospectivamente 215 estudios 18F-FDG-PET/TC para estatificación inicial de cáncer de pulmón entre marzo de 2011 y diciembre de 2015; se incluyeron 57(26,5%) mujeres y 158(73,5%) hombres, con edades de 34 a 88 años (media±DE: 67,23±10,04); hubo 82 estadios quirúrgicos (I, II, IIIA) y 133 no quirúrgicos (IIIB, IV). El tumor primario fue analizado obteniendo los parámetros SUVmax, metabolic active tumour volume (MATV), total lesion glycolisys (TLG) y el índice de heterogeneidad entropía (ET). La heterogeneidad fue valorada visualmente. Se registró la fecha de fallecimiento y/o el tiempo de seguimiento, que osciló entre 0,70 y 67,60 meses (media±DE: 23,20±17,68). Resultados. En el análisis multivariante, la ET se mostró mejor predictor de supervivencia que el análisis visual de heterogeneidad, el cual no fue estadísticamente significativo. La determinación del C-index demostró que todos los parámetros cuantitativos fueron predictores de supervivencia estadísticamente significativos. Se obtuvieron puntos de corte para comparar los tiempos de supervivencia. En el análisis multivariante, el mejor predictor fue el TNM, pero el MATV, el ET y el género masculino demostraron ser predictores de supervivencia independientes estadísticamente significativos. En los estadios no quirúrgicos, el mejor predictor fue el TNM, pero el MATV y el género masculino demostraron ser predictores de supervivencia estadísticamente significativos e independientes. En los estadios quirúrgicos, la ET fue el único predictor de supervivencia estadísticamente significativo e independiente. Conclusiones. La cuantificación ofrece información pronóstica adicional al análisis visual del 18F-FDG-PET/TC (AU)

18F-FDG PET/CT in lung cancer. The added value of quantification.

OBJECTIVE: To test a software application for the quantification of metabolic heterogeneity and to evaluate its superiority in relation to visual interpretation. To investigate if a quantitative analysis adds information to the interpretation of 18F-FDG-PET/CT. MATERIAL AND METHODS: The study analyzed 215 patients with a 18F-FDG-PET/CT done for the initial staging of lung cancer between March 2011 and December 2015. The study included 57 (26.5%) women and 158 (73.5%) men, with ages ranging from 34 to 88 years (mean±SD: 67.23±10.04). There were 82 surgical stages (I, II, IIIA), and 133 non-surgical stages (IIIB, IV). The primary tumour was analyzed quantitatively by obtaining the following parameters: SUVmax, metabolic active tumour volume (MATV), total lesion glycolysis (TLG), and the entropy heterogeneity index (ET). Heterogeneity was assessed visually. Death dates and/or the follow-up time were registered, ranging from 0.70 to 67.60 months (mean±SD: 23.20±17.68). RESULTS: In multivariate analysis, ET emerged as a better predictor of survival than visual analysis of heterogeneity that was not statistically significant. The C-index determination demonstrated that all quantitative parameters were statistically-significant predictors of survival. Cut-offs were obtained in order to compare survival times. A multivariate analysis was performed. In the total population, the best predictor was the TNM stage, but MATV, ET, and male gender were statistically significant and independent predictors of survival. In stages without surgical indication, the best predictor was the TNM stage, but the MATV and male gender were statistically significant and independent predictors of survival. In the surgical stages, ET was the only statistically significant and independent predictor of survival. CONCLUSIONS: Quantification adds prognostic information to the visual analysis of 18F-FDG-PET/CT.

The value of quantitative analysis in 18F-NaF PET/CT / El valor del análisis cuantitativo en la PET/TC con 18F-FNa

Aim. To evaluate the ability of SUVmax to differentiate bone metastases from degenerative lesions, blastic from lytic metastases, as well as to determine the correlation between SUVmax with 18F-NaF and with 18F-FDG. Material and methods. A review was performed on 115 18F-NaF PET/CT studies. Of the 64 patients with bone metastases, 49 (39 women, 10 men, 61±12 years (16-81)), in whom the PET/CT supported the diagnosis of bone metastases, were selected for analysis. A record was made of the SUVmax of a maximum of ten metastases in each patient (total 172: 141 blastic, 31 lytic), as well as four degenerative lesions (total 188) with the greatest 18F-NaF uptake intensity. Of the 49 patients analyzed, 43 also had a 18F-FDG PET/CT performed in which a record was made of the SUVmax values for 18F-FDG calculated in the locations corresponding to the bone metastases observed in the 18F-NaF PET/CT: 128 metastases (106 blastic, 22 lytic). Results. The mean of the SUVmax values was significantly higher in metastases than in degenerative lesions, 26.8±17.3 vs. 15.3±6.3 (P<0.001) and in blastic than in lytic metastases, 27.9±18.3 vs. 22.1±11.3 (P=0.03). A SUVmax value above 42 always represented metastases, with all values above 49 representing blastic metastases. Using the SUVmax values, it was possible to predict the occurrence of metastases (AUC=0.723; P<0.001; 95% CI=0.671-0.776). The mean of the SUVmax with 18F-NaF was significantly higher in blastic metastases (27.9±18.3 vs. 22.1±11.3, P=0.03), whereas with 18F-FDG it was significantly higher in lytic ones (3.9±3.4 vs. 9.6±3.3; P<0.01). Conclusions. SUVmax can contribute to the differentiation of metastases from degenerative lesions, and blastic from lytic metastases (AU)

Objetivo. Evaluar la capacidad del SUVmax para diferenciar metástasis óseas de lesiones degenerativas, metástasis blásticas de líticas, así como la relación del SUVmax con 18F-FNa y con 18F-FDG. Material y métodos. Revisamos 115 exploraciones de PET/TC con 18F-FNa. De 64 pacientes con metástasis óseas, se seleccionaron 49 en los que la TC de la PET/TC apoyaba el diagnóstico de metástasis óseas: 39 mujeres y 10 hombres, 61±12 años (16-81). En cada paciente se calculó el SUVmax en un máximo de 10 metástasis (total 172: 141 blásticas, 31 líticas) y 4 lesiones degenerativas (total 188) que presentaban la mayor captación de 18F-FNa. De los 49 pacientes analizados, en 43 también se había realizado una exploración PET/TC con 18F-FDG y se calculó el valor de SUVmax para la 18F-FDG en las localizaciones correspondientes a las metástasis óseas observadas en la PET/TC con 18F-FNa: 128 metástasis (106 blásticas, 22 líticas). Resultados. El SUVmax promedio fue más elevado en las metástasis que en las lesiones degenerativas, 26,8±17,3 vs. 15,3±6,3 (p<0,001), y más elevado también en las metástasis blásticas que en las líticas: 27,9±18,3 vs. 22,1±11,3 (p=0,03). Todas las metástasis presentaron un valor de SUVmax>42 y las blásticas>49. La utilización del SUVmax permitió predecir la presencia de metástasis (AUC=0,723; p<0,001; IC95%=0,671-0,776). El valor medio de SUVmax con 18F-FNa fue significativamente más alto en las metástasis blásticas (27,9±18,3 vs. 22,1±11,3; p=0,03), mientras que el de 18F-FDG fue significativamente más alto en las líticas (3,9±3,4 vs. 9,6±3,3; p<0,01). Conclusiones. El SUVmax puede ayudar a diferenciar metástasis de lesiones degenerativas y metástasis blásticas de líticas (AU)

The value of quantitative analysis in 18F-NaF PET/CT.

AIM: To evaluate the ability of SUVmax to differentiate bone metastases from degenerative lesions, blastic from lytic metastases, as well as to determine the correlation between SUVmax with 18F-NaF and with 18F-FDG. MATERIAL AND METHODS: A review was performed on 115 18F-NaF PET/CT studies. Of the 64 patients with bone metastases, 49 (39 women, 10 men, 61±12 years (16-81)), in whom the PET/CT supported the diagnosis of bone metastases, were selected for analysis. A record was made of the SUVmax of a maximum of ten metastases in each patient (total 172: 141 blastic, 31 lytic), as well as four degenerative lesions (total 188) with the greatest 18F-NaF uptake intensity. Of the 49 patients analyzed, 43 also had a 18F-FDG PET/CT performed in which a record was made of the SUVmax values for 18F-FDG calculated in the locations corresponding to the bone metastases observed in the 18F-NaF PET/CT: 128 metastases (106 blastic, 22 lytic). RESULTS: The mean of the SUVmax values was significantly higher in metastases than in degenerative lesions, 26.8±17.3 vs. 15.3±6.3 (P<0.001) and in blastic than in lytic metastases, 27.9±18.3 vs. 22.1±11.3 (P=0.03). A SUVmax value above 42 always represented metastases, with all values above 49 representing blastic metastases. Using the SUVmax values, it was possible to predict the occurrence of metastases (AUC=0.723; P<0.001; 95% CI=0.671-0.776). The mean of the SUVmax with 18F-NaF was significantly higher in blastic metastases (27.9±18.3 vs. 22.1±11.3, P=0.03), whereas with 18F-FDG it was significantly higher in lytic ones (3.9±3.4 vs. 9.6±3.3; P<0.01). CONCLUSIONS: SUVmax can contribute to the differentiation of metastases from degenerative lesions, and blastic from lytic metastases.

[A new method for quantification of hepatobiliary scintigraphy using 99mTc-mebrofenin. A comparative study]. / Un nuevo método para la cuantificación de grammagrafía hepatobiliar utilizando 99mTcmebrofenina. Un estudio de comparación.

A method based upon the application of mathematical techniques of deconvolution on the classical compartmental model for the quantitative study of liver function from hepatobiliary scintigraphy using 99mTc-mebrofenin data is proposed. The theory in which the method is based upon is presented and a comparison with a published methodology of obtaining the hepatic extraction after scintigraphic sudies has been performed using the results on 36 rats studies obtained with the two methods. A highly significant correlation between the two techniques was verified. The characteristics of the two methodologies, the proposed one based upon a theoretical approach and the other one on an empirical approximation are discussed. Comments are made on the interest and limitations of the presented technique that may be an useful tool for the evaluation of hepatic insufficiency.

Un nuevo método para la cuantificación de grammagrafía hepatobiliar utilizando 99mtc-mebrofenina. Un estudio de comparación / A new method for quantification of hepatobiliary scintigraphy using 99mTc-mebrofenin. A comparative study

Se propone un método basado en la aplicación de técnicas matemáticas de deconvolución sobre el modelo compartimental clásico para el estudio cuantitativo de la función hepática con datos de gammagrafía hepatobiliar con 99mTc-mebrofenina. Se presenta la teoría sobre la cual se basa el método y se hace una comparación con una metodología publicada para la obtención de la extracción hepática después de hacer estudios grammagráficos utilizando los resultados de 36 estudios en ratas, obtenidos con los dos métodos. Se comprobó una correlación altamente significativa entre las dos técnicas. Se discuten las características de las dos metodologías, la propuesta basada en un enfoque teórico y la otra en un enfoque empírico. Se comenta el interés y limitaciones de la técnica presentada que puede ser una herramienta útil para la evaluación de la insuficiencia hepática. (AU)