Optique non lineaire dans des milieux a interet biologique

SIGLEINIST T 76431 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Total Lesion Glycolysis in Early-Stage Non-Small Cell Lung Cancer: Proposal for an Alternative Dimensionless Volume-Based Parameter.

International audienceA derivation leads to a proposal for a further volume-based parameter, which is total lesion glycolysis divided by patient weight. Determining whether the use of TLG/W in the NSCLC patient series of Hyun et al. increases the significance level of their results, would help to assess the clinical prognosis interest of this alternative dimensionless volume-based parameter

Total Lesion Glycolysis in Early-Stage Non-Small Cell Lung Cancer: Proposal for an Alternative Dimensionless Volume-Based Parameter.

International audienceA derivation leads to a proposal for a further volume-based parameter, which is total lesion glycolysis divided by patient weight. Determining whether the use of TLG/W in the NSCLC patient series of Hyun et al. increases the significance level of their results, would help to assess the clinical prognosis interest of this alternative dimensionless volume-based parameter

An abbreviated therapy-dosimetric equation for the companion diagnostic/therapeutic [64/67Cu]Cu-SARTATE

International audienceIn a preclinical model of neuroblastoma, Dearling et al. recently demonstrated the potential interest for a theranostic approach of [64/67Cu]Cu-SARTATE for the detection and treatment of SSTR2-positive neuroblastoma lesions in pediatric patients whose widespread metastases survive initial therapy as minimal residual disease (MRD). MRD may be detected by [64Cu]Cu-SARTATE and subsequently treated by [67Cu]Cu-SARTATE. Since therapeutic dosimetry estimation of the latter agent from the uptake of the former one in the initial diagnostic scan was not addressed, the present theoretical commentary proposes the derivation of an abbreviated therapy-dosimetric equation for the companion diagnostic/therapeutic [64/67Cu]Cu-SARTATE that might be of interest for future clinical theranostic practice

Modelling analysis of centroid curves of olfactory habituation in humans

Indexation en cours.International audiencePreviously published experiments established the time-course of olfactory habituation in humans, and extracted 3 centroid curves from clustering analysis that reflected high, middle and low habituation. The aim of the current theoretical study was to further analyse these previous experimental data by developing a mathematical modelling analysis designed for fitting the 3 curves from a general equation. After adjusting equation parameters for each curve, fitting equation outcomes on experimental data yielded high correlation coefficients of 0.9997 – 0.9995 – 0.9962, respectively. A model-based interpretation of olfactory-habituation centroid curves is proposed suggesting that they result from the effect of 2 separate processes that act simultaneously. We suggest that the first process is unlikely related to the olfactory habituation itself, and, rather, is of unclear origin. The second process seems to play a major role in the degree of OH and cannot be assigned, a priori, to either peripheral or central adaptation, respectively

Calculating an estimate of tissue integrated activity in 18F-FDG PET imaging using one SUV value.

International audienceBACKGROUND: A kinetic model analysis was recently proposed to estimate the 18F-fluorodeoxyglucose (18F-FDG) integrated activity in an arbitrary tissue that uses tracer uptake and release rate constants. The aim of the current theoretical paper was to estimate 18F-FDG integrated activity using one standardized uptake value (SUV). METHODS: A further kinetic model analysis allowed us to derive an analytical solution for integrated activity determination, involving both irreversible and reversible trapping. It only uses SUV, which is uncorrected for 18F physical decay (SUVuncorr, in g.mL-1) and is assessed about its peak value. Measurement uncertainty of the estimate was also assessed. RESULTS: In a tissue (volume V, in mL) that irreversibly traps 18F-FDG, the total number of disintegrations can be estimated as: AC = 162 * 105 * SUVuncorr * V * ID / W (ID, injected dose, in MBq; W, patient's weight, in kg), where SUVuncorr is a mean over V and is assessed between 55 and 110 min after tracer injection. The relative uncertainty ranges between 18% and 30% (the higher the uptake, the lower the uncertainty). Comparison with the previous Zanotti-Fregonara's model applied to foetus showed less than 16% difference. Furthermore, calculated integrated activity estimates were found in good agreement with Mejia's results for healthy brain, lung and liver that show various degrees of tracer trapping reversibility and various fractions of free tracer in blood and interstitial volume. CONCLUSION: Estimation of integrated activity in an arbitrary tissue using one SUV value is possible, with measurement uncertainty related to required assumptions. A formula allows quick estimation that does not underestimate integrated activity so that it could be helpful in circumstances such as accidental exposure, or for epidemiologic purposes such as in patients having undergone several examinations

SUVpeak performance in Lung Cancer: Comparison to Average SUV from 40 Hottest Voxels

The performance of an average standard uptake value (SUV) over a 1-mL-volume sphere within an (18)F-FDG-positive lesion resulting in the highest possible value (SUVpeakW), was compared to that of an average SUV computed from the 40 hottest voxels, irrespective of their location within the lesion (SUVmax-40). METHODS A PET dynamic acquisition performed in 20 lung cancer lesions yielded for each SUV metric its mean value, relative measurement error and repeatability (MEr-R). RESULTS SUVpeakW mean value was significantly 9.66% lower than that of SUVmax-40 (P<0.0001). SUVpeakW and SUVmax-40 MEr-R were significantly lower than MEr-R of SUVmax (the hottest voxel): 9.35-13.21%, 8.84-12.49% versus 13.86-19.59% respectively (95%-CL; P<0.0001). Although being marginal, SUVpeakW MEr-R were not significantly greater than SUVmax-40 MEr-R (P = 0.086). CONCLUSION SUVmax-40 is more likely to represent the most metabolically active portions of tumors than SUVpeakW, with close variability performance