| 1. |
- Buntic-Ogor, Ivana, et al.
(author)
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An Adaptive Turbulence Model for Swirling Flow
- 2006
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In: Conference on Turbulence and Interactions, TI2006, May 29 - June 2, 2006, Porquerolles, France.
-
Conference paper (peer-reviewed)abstract
- Swirling flows are very common in technical applications, especially in hydraulic machinery, and they require rather sophisticated modeling. At present, an applicative method for simulating unsteady flows is Very Large Eddy Simulation (VLES). In VLES, large turbulence structures are resolved in time and space, while the small scales are modeled with an adequate turbulence model. Therefore the turbulence model must be able to distinguish between the resolved and the unresolved scales. In order to accomplish this the method used in this work employs an adaptive and dynamic filtering technique that restricts the turbulence model to only predict the effect of non-resolvable turbulent scales. The results obtained from using the standard k-ε model is compared to those using the extended model of Chen and Kim, with and without the filtering approach. The modified k-ε model of Reif et al. is also investigated together with the filtering approach. The models are implemented in the FENFLOSS and the CALC-PMB CFD codes. The chosen test cases are swirling flow in a straight pipe and swirling flow through a straight conical diffuser.
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| 2. |
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| 3. |
- Gyllenram, Walter, 1971, et al.
(author)
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Design and Validation of a Scale-Adaptive Filtering Technique for LRN Turbulence Modeling of Unsteady Flow
- 2008
-
In: Journal of Fluid Engineering. ; Volume 130:Issue 5, s. 10-
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Journal article (peer-reviewed)abstract
- An adaptive low-pass filtering procedure for the modeled turbulent length and time scales is derived and applied to Wilcox' original low reynolds number k-omega turbulence model. It is shown that the method is suitable for complex industrial unsteady flows in cases where full large eddy simulations (LESs) are unfeasible. During the simulation, the modeled length and time scales are compared to what can potentially be resolved by the computational grid and time step. If the modeled scales are larger than the resolvable scales, the resolvable scales will replace the modeled scales in the formulation of the eddy viscosity. The filtered k-omega model is implemented in an in-house computational fluid dynamics (CFD) code, and numerical simulations have been made of strongly swirling flow through a sudden expansion. The new model surpasses the original model in predicting unsteady effects and producing accurate time-averaged results. It is shown to be superior to the wall-adpating local eddy-viscosity (WALE) model on the computational grids considered here, since the turbulence may not be sufficiently resolved for an accurate LES. Because of the adaptive formulation, the filtered k-omega model has the potential to be successfully used in any engineering case where an LES is unfeasible and a Reynolds (ensemble) averaged Navier–Stokes simulation is insufficient.
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| 4. |
- Gyllenram, Walter, 1971, et al.
(author)
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Large Eddy Simulation of Turbulent Swirling Flow Through a Sudden Expansion
- 2006
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In: 23rd IAHR Symposium, Yokohama, Japan, October 2006.
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Conference paper (peer-reviewed)abstract
- Turbulent swirling flow through a sudden expansion is investigated numerically using Large Eddy Simulation (LES). The flow resembles the flow in a draft tube of a water turbine that is working at part load. The swirling inflow is subject to a strong adverse pressure gradient and the symmetry of the flow breaks down close to the inlet. This gives rise to an oscillating, helicoidal vortex core which in turn creates a highly unsteady and turbulent flow field. In this work, the large-scale turbulent structures are numerically resolved, and detailed information about the flow characteristics is obtained. The oscillating flow is analysed using Fourier transforms of the wall pressure at different downstream locations. The most dominant frequency corresponds to the rotational rate of the precessing vortex core, and it is found that this frequency is constant throughout the domain. The results of two simulations using numerical discretization schemes of different order are compared. It is shown that the frequency of the precessing vortex core is not sensitive to the choice of discretization. However, the lower frequencies of the flow depend to a higher extent on the numerical accuracy. To validate the results, the computed velocities are averaged and compared to experimental data. The agreement is good. The Reynolds stress tensor is also computed and analysed. It is found that large degrees of turbulent anisotropy are found only in the region that is dominated by the oscillating vortex core. Further downstream, the degree of turbulent anisotropy is almost negligible despite the relatively higher level of swirl.
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| 5. |
- Gyllenram, Walter, 1971, et al.
(author)
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On the failure of the quasicylindrical approximation and the connection to vortex breakdown in turbulent swirling flow
- 2007
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In: Physics of Fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; 19:4
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Journal article (peer-reviewed)abstract
- This paper analyses the properties of viscous swirling flow in a pipe. The analysis is based on the time-averaged quasi-cylindrical Navier-Stokes equations and is applicable to steady, unsteady and turbulent swirling flow. A method is developed to determine the critical level of swirl (vortex breakdown) for an arbitrary vortex. The method can also be used for an estimation of the radial velocity profile if the other components are given or measured along a single radial line. The quasi-cylindrical equations are rearranged to yield a single ordinary differential equation for the radial distribution of the radial velocity component. The equation is singular for certain levels of swirl. It is shown that the lowest swirl level at which the equation is singular corresponds exactly to the sufficient condition for axisymmetric vortex breakdown as derived by Wang and Rusak [J. Fluid Mech. {340}, 177-223 (1997)] and Rusak et al. [AIAA J. {36}, 1848-1853 (1998)]. In narrow regions around the critical levels of swirl, the solution violates the quasi-cylindrical assumptions and the flow must undergo a drastic change of structure. The critical swirl level is determined by the sign change of the smallest eigenvalue of the discrete linear operator which relates the radial velocities to effects of viscosity and turbulence. It is shown that neither viscosity nor turbulence directly alters the critical level of swirl.
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| 6. |
- Gyllenram, Walter, 1971, et al.
(author)
-
Very Large Eddy Simulations of Draft Tube Flow
- 2006
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In: 23rd IAHR Symposium, Yokohama, Japan, October 2006.
-
Conference paper (peer-reviewed)abstract
- The objective of this work is to improve numerical predictions of unsteady turbulent flows in the draft tubes of hydraulic power plants. The standard two-equation turbulence models are known to have a strong damping effect on the resolved turbulence in this type of flow. In order to reduce this negative influence of the model, while retaining the usually satisfying near-wall behaviour, a dynamic filtering technique of the turbulent length and time scales is generalised, employed and evaluated. The filter limits the influence of the modeled turbulent length and time scales on the mean flow in regions where unsteadiness can potentially be resolved. The Wilcox (1988) $k-\omega$ turbulence model was chosen as basis for the investigations, and the effects of five different filter widths were examined. The original non-filtered model is also evaluated. A swirling flow through a straight axisymmetric diffuser was chosen as a test case and detailed measurements carried out by Clausen et al. were used to validate the numerical results. The influence of the filtering approach on the resolved frequencies and the time averaged solutions were analysed. It is shown that the filtering procedure gives better predictions of the time-averaged velocity field and more information on the large scale unsteadiness.
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| 7. |
- Aksyutina, Yu, et al.
(author)
-
Lithium isotopes beyond the drip line
- 2008
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In: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 666:5, s. 430-434
-
Journal article (peer-reviewed)abstract
- The unbound isotopes 10Li, 12Li and 13Li have been observed after nucleon-knockout reactions at relativistic energies with 11Li and 14Be beams impinging on a liquid hydrogen target. The channels , and were analysed in the ALADIN-LAND setup at GSI. The 10Li data confirm earlier findings, while the 12Li and 13Li nuclei were observed for the first time. The relative-energy spectrum shows that the ground state of 12Li can be described as a virtual s-state with a scattering length of -13.7(1.6) fm. A broad energy spectrum was found for the channel. Based on the assumption that the relative-energy spectrum is dominated by a correlated background presumably stemming from initial correlations in the 14Be ground-state, evidence for a 13Li resonance at 1.47(31) MeV above the threshold with a width around 2 MeV has been found.
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| 8. |
- Aksyutina, Yuliya, 1983, et al.
(author)
-
Properties of the 7He ground state from 8He neutron knockout
- 2009
-
In: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 679:3, s. 191-196
-
Journal article (peer-reviewed)abstract
- The unbound nucleus 7He, produced in neutron-knockout reactions with a 240 MeV/u 8He beam in a liquid-hydrogen target, has been studied in an experiment at the ALADIN-LAND setup at GSI. From an R-matrix analysis the resonance parameters for 7He as well as the spectroscopic factor for the 6He(0+) + n configuration in its ground-state have been obtained. The spectroscopic factor is 0.61 confirming that 7He is not a pure single-particle state. An analysis of 5He data from neutron-knockout reactions of 6He in a carbon target reveals the presence of an s-wave component at low energies in the α+n relative energy spectrum. A possible low-lying exited state in 7He observed in neutron knockout data from 8He in a carbon target and tentatively interpreted as a Iπ=1/2− state, could not be observed in the present experiment. Possible explanations of the shape difference between the 7He resonance obtained in the two knockout reactions are discussed in terms of target-dependence or different reaction mechanisms at relativistic energies.
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| 9. |
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| 10. |
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| 11. |
- Karlsson, Martin, et al.
(author)
-
Influence of inlet boundary conditions in the prediction of rotor dynamic forces and moments for a hydraulic turbine using CFD
- 2008
-
In: ISROMAC-12. - Honolulu.
-
Conference paper (peer-reviewed)abstract
- The rotordynamic behavior of a hydraulic turbine is influenced by fluid-rotor interactions at the turbine runner. In this paper computational fluid dynamics (CFD) is used to numerically predict the rotordynamical excitation forces due to the flow through a hydraulic turbine runner. The simulations are carried out for three different boundary conditions. One axi-symmetric inlet boundary condition, and two axi-periodic boundary conditions. The two latter are obtained from separate simulations of wicket gate and spiral casing flow. It is found that the inlet boundary condition significantly affects the rotordynamical forces and moments.
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| 12. |
- Karlsson, Martin, et al.
(author)
-
Numerical estimation of torsional dynamic coefficients of a hydraulic turbine
- 2009
-
In: International Journal of Rotating Machinery. - : Hindawi Limited. - 1023-621X .- 1542-3034.
-
Journal article (peer-reviewed)abstract
- The rotordynamic behavior of a hydraulic turbine is influenced by fluid-rotor interactions at the turbine runner. In this paper computational fluid dynamics (CFDs) are used to numerically predict the torsional dynamic coefficients due to added polar inertia, damping, and stiffness of a Kaplan turbine runner. The simulations are carried out for three operating conditions, one at about 35% load, one at about 60% load (near best efficiency), and one at about 70% load. The runner rotational speed is perturbed with a sinusoidal function with different frequencies in order to estimate the coefficients of added polar inertia and damping. It is shown that the added coefficients are dependent of the load and the oscillation frequency of the runner. This affect the system's eigenfrequencies and damping. The eigenfrequency is reduced with up to 65% compared to the eigenfrequency of the mechanical system without the fluid interaction. The contribution to the damping ratio varies between 30-80% depending on the load. Hence, it is important to consider these added coefficients while carrying out dynamic analysis of the mechanical system.
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| 13. |
- Kölby, Lars, 1963, et al.
(author)
-
Successful receptor-mediated radiation therapy of xenografted human midgut carcinoid tumour
- 2005
-
In: British journal of cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 93:10, s. 1144-51
-
Journal article (peer-reviewed)abstract
- Somatostatin receptor (sstr)-mediated radiation therapy is a new therapeutic modality for neuroendocrine (NE) tumours. High expression of sstr in NE tumours leads to tumour-specific uptake of radiolabelled somatostatin analogues and high absorbed doses. In this study, we present the first optimised radiation therapy via sstr using [(177)Lu-DOTA(0)-Tyr(3)]-octreotate given to nude mice xenografted with the human midgut carcinoid GOT1. The tumours in 22 out of 23 animals given therapeutic amounts showed dose-dependent, rapid complete remission. The diagnostic amount (0.5 MBq [(177)Lu-DOTA(0)-Tyr(3)]-octreotate) did not influence tumour growth and was rapidly excreted. In contrast, the therapeutic amount (30 MBq [(177)Lu-DOTA(0)-Tyr(3)]-octreotate) induced rapid tumour regression and entrapment of (177)Lu so that the activity concentration of (177)Lu remained high, 7 and 13 days after injection. The entrapment phenomenon increased the absorbed dose to tumours from 1.6 to 4.0 Gy MBq(-1) and the tumours in animals treated with 30 MBq received 120 Gy. Therapeutic amounts of [(177)Lu-DOTA(0)-Tyr(3)]-octreotate rapidly induced apoptosis and gradual development of fibrosis in grafted tumours. In conclusion, human midgut carcinoid xenografts can be cured by receptor-mediated radiation therapy by optimising the uptake of radioligand and taking advantage of the favourable change in biokinetics induced by entrapment of radionuclide in the tumours.
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| 14. |
- Lidén, Hans, 1971, et al.
(author)
-
The feasibility of left ventricular mechanical support as a bridge to cardiac recovery.
- 2007
-
In: European journal of heart failure : journal of the Working Group on Heart Failure of the European Society of Cardiology. - : Wiley. - 1388-9842 .- 1879-0844. ; 9:5, s. 525-30
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: To study the achievability of device weaning in patients receiving left ventricular assist devices (LVADs) as a bridge to transplantation. METHODS: Eighteen consecutive patients receiving a LVAD between September 1997 and June 2002 were included in the study. During a four-month follow-up, patients were repeatedly evaluated with right heart catheterization and echocardiography and, if functional improvement was observed, studied with the device turned off. Cardiac recovery was defined as off-pump LVEF>or=40% together with a significant improvement in invasive haemodynamic measurements (CI>or=2.5 and PCWP
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| 15. |
- Muntean, Sebastian, et al.
(author)
-
3D numerical analysis of the unsteady turbulent swirling flow in a conical diffuser using Fluent and OpenFOAM
- 2009
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In: Proceedings of the 3rd IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems. ; 1, s. 155-164
-
Conference paper (peer-reviewed)abstract
- The paper presents three-dimensional numerical investigations of the unsteady swirling flow in a conical diffuser with a precessing vortex rope. The helical vortex breakdown, also known as precessing vortex rope in the engineering literature, benefits from a large body of literature aimed either at elucidating the physics of the phenomenon and building mathematical models, or at developing and testing practical solutions to control the causes and/or the effects. In this paper we investigate the unsteady hydrodynamic fields with a well-known precessing vortex rope computed with the FLUENT and OpenFOAM CFD codes. The main goal is to elucidate the physics of the phenomenon. The three-dimensional computational domain corresponds to the test section of a test rig designed and developed at Politehnica University of Timisoara. The same domain and grid with two millions cells is considered in both codes. The boundary conditions and problem setup are presented for each case. The unsteady pressure fluctuations along to the element of the conical diffuser are recorded. The numerical pressure fluctuations are validated against experimental data measured on the wall of the test rig. Consequently, the fundamental frequency and higher harmonics of the vortex rope is determined by a Fourier analysis.
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| 16. |
- Nilsson, Håkan, 1971
(author)
-
Evaluation of OpenFOAM for CFD of turbulent flow in water turbines
- 2006
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In: IAHR 2006.
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Conference paper (peer-reviewed)abstract
- The purpose of this study is to evaluate the newly distributed OpenFOAM (www.openfoam.org) OpenSource CFD tool for turbulent flow in water turbines. The aim is to validate the OpenFOAM results for cases that have also been computed with other CFD codes, as well as have been experimentally investigated. Comparisons are made both with numerical and experimental results.The first case studied is the steady flow in the Hölleforsen (Turbine-99) draft tube. The OpenFOAM result proved to be comparable with results from all the major CFD tools on the market according to the proceedings from the Turbine-99 III workshop in December 2005 (www.turbine-99.org). An unsteady computation of the flow in the same draft tube has also been made, yielding an unsteady vortex rope with a period of 0.48s. All OpenFOAM draft tube results are similar to results obtained with CFX-5, and the results are close to the experimental results.The second case studied is the steady flow in the Hölleforsen runner. The computations have been performed both for a single runner blade passage using periodic boundaries, and for the full runner, yielding the same results. In all cases the tip clearance has been included and computations both with and without the runner blade clearance at the hub has been made. The computational results compare well with the experimental results.All the computations use wall-function grids and turbulence is modelled using the standard k-epsilon model.
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| 17. |
- Nilsson, Håkan, 1971
(author)
-
Experiences with OpenFOAM for water turbine applications
- 2007
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In: Proceedings of the 1st OpenFOAM International Conference, 26-27 November 2007, Beaumont House, Old Windsor, United Kingdom..
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Conference paper (peer-reviewed)abstract
- OpenFOAM has been used successfully at Chalmers for water turbine applications since the beginning of 2005. OpenFOAM has been validated for the flow in a Kaplan water turbine runner and draft tube, and for the swirling unsteady flow in a combustor. The flow in the combustor resembles the flow in a water turbine draft tube (which is a diffuser), with its adverse pressure gradient and unsteady flow features. The results compare well with the experimental results. For the flow in the draft tube the OpenFOAM results are almost identical to those of the CFX-5 CFD code. For the flow in the combustor the OpenFOAM results show the same trend as the results using the Fluent CFD code. OpenFOAM gives similar results as the CALC-PMB in-house CFD code that was developed specifically for water turbine applications (however, no comparisons are shown here).Many interesting flow features in water turbines are unsteady. There is an interaction between steady and rotating parts of the machine, which should be properly resolved. There are also flow instabilities like the break-up of the vortex after the runner, yielding a highly unsteady flow (here referred to as the vortex rope). A CFD code used for water turbine applications should thus be able to include rotor-stator interaction and allow unsteady flow features to appear without numerical damping. OpenFOAM is not yet fully developed for full rotor-stator interaction in water turbines. In the present work a rotating inlet boundary condition is shown, which makes it possible to include guide vane wakes or non-axisymmetry from the spiral casing from a previous simulation of the distributor. The present work evaluates a newly developed filtering technique for the $k-\omega$ SST turbulence model. It is shown that the filter is necessary to get unsteady and accurate time averaged results of the flow in the combustor.The Reynolds numbers in water turbines are high, the geometries are complicated, and the computational grids are usually coarse and skew. It is thus necessary to use models and methods that can give accurate results also under non-ideal conditions.
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| 18. |
- Nilsson, Håkan, 1971, et al.
(author)
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OpenFOAM SIMULATION OF THE FLOW IN THE HöLLEFORSEN DRAFT TUBE MODEL
- 2005
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In: Turbine-99 III workshop.
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Conference paper (peer-reviewed)abstract
- This paper presents OpenFOAM computational results of the flow in the Hölleforsen hydraulic turbine draft tube model. It is a contribution to the third Turbine-99 workshop on draft tube flow (www.turbine-99.org). The boundary conditions and the wall-function grid of 'Case 1: Steady calculation' is used. Turbulence is modelled using the standard k-epsilon model with wall functions. The results are analysed at sections where detailed measurements are available. Detailed comparisons between the results presented in this paper, computational contributions from other participants, and measurements are available in the workshop proceedings (see www.turbine-99.org).
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| 19. |
- Nilsson, Håkan, 1971
(author)
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Some experiences on the accuracy and parallel efficiency of OpenFOAM for CFD in water turbines
- 2007
-
In: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - 1611-3349 .- 0302-9743. - 9783540757542 ; 4699/2007, s. 168-176
-
Conference paper (other academic/artistic)abstract
- 50% of the electric power in Sweden is generated by water power. Many of the power plants in Sweden are getting old and some major refurbishments are coming up. Due to the development of numerical methods and computer power the last decades Computational Fluid Dynamics (CFD) is to a large extent used as a design tool for this purpose. The general features of the flow in water turbines can be resolved with todays methods and computational power, but in order to study the flow in detail enormous HPC facilities and new methods are required.The present work presents the water turbine field with its HPC requirements, shows some state-of-the-art results from OpenFOAM CFD analysis, and presents a parallel performance analysis on a Linux cluster using an ordinary gigabit interconnect v.s. an Infiniband interconnect.
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| 20. |
- Nilsson, Håkan, 1971, et al.
(author)
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The OpenFOAM Turbomachinery Working Group, and Conclusions from the Turbomachinery Session of the Third OpenFOAM Workshop
- 2008
-
In: 24th IAHR Symposium on Hydraulic Machinery and Systems, Foz do Iguassu, Brazil.
-
Conference paper (peer-reviewed)abstract
- The OpenFOAM CFD toolbox was released as OpenSource December 10, 2004, and since then the number of users throughout the world has increased dramatically. Many industries concerned with turbomachinery (water turbines) are investing a lot of money each year in commercial CFD solvers. The availability of cheap hardware makes it possible to do simulations on a large number of CPUs, which requires many expensive software licenses. There is thus a need for a high quality CFD tool that is cheap, and OpenFOAM is the first tool to meet those demands. OpenFOAM has many of the features that are available in the commercial CFD codes, and due to the OpenSource distribution under the GPL licence it can be used at no cost. There is however a need to develop and maintain some of the features that are specifically needed for turbomachinery applications, and for that reason a turbomachinery Working Group of OpenFOAM users was formed at the second OpenFOAM workshop in Zagreb 2007. The first task of the working group has been to contribute to the set-up of the OpenFOAM-extend project at SourceForge, which is used as a platform for the collaborative effort within the working group, as well as a way to distribute the work to anyone who need to take part of it. The second task of the working group has been to organize a turbomachinery session at the third OpenFOAM workshop in Milano 2008. At that workshop the ERCOFTAC conical diffuser was studied as a validation testcase for OpenFOAM.The present paper describes the OpenFOAM CFD toolbox, and the features that are of interest to the water turbine community. It will further present the OpenFOAM Turbomachinery Working Group, the ERCOFTAC conical diffuser validation testcase for OpenFOAM, the conclusions from the turbomachinery session of the third OpenFOAM workshop, and the OpenFOAM-extend project at SourceForge.
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| 21. |
- Petit, Olivier, 1980, et al.
(author)
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The ERCOFTAC centrifugal pump OpenFOAM case-study
- 2009
-
In: IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems. - 9788021439474 ; , s. 523-532
-
Conference paper (peer-reviewed)abstract
- This work investigates the rotor-stator interaction features of OpenFOAM-1.5-dev, such as frozenrotor and sliding grid. The case studied is the ERCOFTAC Test Case U3: Centrifugal Pump with aVaned Diffuser, a testcase from the ERCOFTAC Turbomachinery Special Interest Group. The casewas presented by Combès at the ERCOFTAC Seminar and Workshop on Turbomachinery FlowPrediction VII, in Aussois, 1999. It is a valid test case for evaluation of rotor-stator interactionfeatures, as detailed experimental data is available.The investigation shows that OpenFOAM gives results that are comparable to the experimental data,in particular for the sliding grid case. The results are less accurate in the frozen rotor simulation due tothe improper treatment of the impeller wakes that is part of the frozen rotor formulation.The ERCOFTAC centrifugal pump OpenFOAM case-study was developed as a contribution to theOpenFOAM Turbomachinery Working Group, and was presented and discussed at the FourthOpenFOAM Workshop in Montréal, 2009. The complete set-up of the case-study is available from theOpenFOAM-extend project at SourceForge, and instructions and comments are available from theOpenFOAM Wiki.
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| 22. |
- Petit, Olivier, 1980, et al.
(author)
-
The flow in the U9 Kaplan turbine - preliminary and planned simulations using CFX and OpenFOAM
- 2008
-
In: 24th IAHR Symposium Hydraulic MAchinery and Systems, Foz Do Iguassu, Brasil.
-
Conference paper (peer-reviewed)abstract
- The present work compares the CFX and OpenFOAM CFD codes with respect to the prediction of the flow in the U9 Kaplan turbine spiral casing, distributor and draft tube. The simulations use similar settings and the same computational grids – unstructured wall-function grids with 10.3M cells in the spiral casing and distributor, and 1.04M cells in the draft tube. The results show that the two codes give similar results in the spiral casing and distributor, and almost identical results in the draft tube. Previous studies [1] have shown the same behaviour in the Turbine-99 draft tube, for a block-structured wall-function grid. There are however no previous studies where the flow in a spiral casing and distributor have been studied and compared using the same settings and computational grid in CFX and OpenFOAM.The next phase of the project consists of comparisons with the results from an on-going experimental investigation.
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| 23. |
- Schmitt, Anneli, 1971, et al.
(author)
-
Differences in biodistribution between 99mTc-depreotide, 111In-DTPA-octreotide, and 177Lu-DOTA-Tyr3-octreotate in a small cell lung cancer animal model
- 2005
-
In: Cancer biotherapy & radiopharmaceuticals. - 1084-9785. ; 20:2, s. 231-6
-
Journal article (peer-reviewed)abstract
- AIM: (177)Lu-DOTA-Tyr(3)-octreotate is a candidate radiopharmaceutical for the therapy of somatostatin receptor (sstr)-positive small cell lung cancer (SCLC). Scintigraphy of lung tumors is made with 2 alternative somatostatin analogs, (111)In-DTPA-octreotide or (99m)Tc-depreotide. The aim of this study was to compare the biodistribution of these 3 radiopharmaceuticals in SCLC xenografted to nude mice. METHODS: Nude mice, bearing tumors from the human SCLC cell line NCI-H69, were intravenously injected with 10 MBq (2.4 microg) (99m)Tc-depreotide and 2 MBq (0.5 microg) (111)In-DTPA-octreotide simultaneously. The activity concentration (%IA/g) was measured in tumor and normal tissue at 2, 4, and 24 hours postinjection (hpi). The results were compared with earlier published biodistribution data of 3 MBq (0.7 microg) (177)Lu-DOTA-Tyr(3)-octreotate in the same animal model. RESULTS: The activity concentration of (111)In-DTPAoctreotide in tumor was higher than the activity concentration of (99m)Tc-depreotide at 2-24 hpi, p < 0.05. The highest tumor uptake at 24 hpi was, however, found for (177)Lu-DOTA-Tyr(3)-octreotate. The activity concentration of (99m)Tc-depreotide was significantly higher in the heart, lungs, liver, the salivary glands, spleen, and bone marrow than for (111)In-DTPA-octreotide at 2-24 hpi. Saturation of the somatostatin receptors may have influenced the uptake in tumor and sstr-positive normal tissues. CONCLUSION: The low tumor-to-lung and tumor-to-liver activity concentration ratios for (99m)Tc-depreotide could result in a lower detection rate of SCLC with this compound versus (111)In-DTPA-octreotide. (177)Lu-DOTA-Tyr(3)-octreotate gave the highest tumor-activity concentration, and has, thus, the best properties for therapy.
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| 24. |
- Swärd, Christina, 1967, et al.
(author)
-
Comparison of [177Lu-DOTA0,Tyr3]-octreotate and [177Lu-DOTA0,Tyr3]-octreotide for receptor-mediated radiation therapy of the xenografted human midgut carcinoid tumor GOT1.
- 2008
-
In: Cancer biotherapy & radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1084-9785 .- 1557-8852. ; 23:1, s. 114-20
-
Journal article (peer-reviewed)abstract
- The aim of this study was to compare the tumor uptake versus time and the tumor response in nude mice transplanted with a human midgut carcinoid (GOT1), when treated with either [(177)Lu-DOTA(0),Tyr(3)]-octreotide or [(177)Lu-DOTA(0),Tyr(3)]-octreotate and to evaluate if plasma chromogranin A (P-CgA) was a reliable marker of tumor response. The tumor uptake and retention of activity of a single intravenous (i.v.) dose (15 MBq) of [(177)Lu-DOTA(0),Tyr(3)]-octreotate or [(177)Lu-DOTA(0),Tyr(3)]-octreotide were compared in nude mice xenografted with GOT1. The activity concentration 24 hours after injection was significantly higher in animals given [(177)Lu-DOTA(0),Tyr(3)]-octreotate versus [(177)Lu-DOTA(0),Tyr(3)]-octreotide (16%+/-1.4% of injected activity per gram [%IA/g] vs. 8.1%+/-2.1% IA/g, mean +/- standard error of the mean) (p=0.00061). The mean absorbed dose was higher in animals given [(177)Lu-DOTA(0),Tyr(3)]-octreotate (46+/-4.3 vs. 17 +/- 3.4 Gy). The reduction of tumor volume was accordingly more prominent in animals given [(177)Lu-DOTA(0),Tyr(3)]-octreotate than in animals given [(177)Lu-DOTA(0),Tyr(3)]-octreotide (p=0.003). The mean tumor volume for animals given [(177)Lu-DOTA(0),Tyr(3)]-octreotate was reduced to 3% of its initial value. P-CgA values were strongly correlated with tumor volume. Octreotate seems to be a more suitable somatostatin analog than octreotide for receptor-mediated radiation therapy. P-CgA is a simple, accurate method for the estimation of tumor response in this animal model.
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