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Carlsson Å, Ljungberg M, Starck G, Forssell-Aronsson E. Degraded water suppression in small volume 1H MRS due to localised shimming. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2011; 24:97-107. [DOI: 10.1007/s10334-010-0239-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 12/15/2010] [Accepted: 12/15/2010] [Indexed: 11/25/2022]
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Nilsson O, Arvidsson Y, Johanson V, Forssell-Aronsson E, Ahlman H. New medical strategies for midgut carcinoids. Anticancer Agents Med Chem 2010; 10:250-69. [PMID: 20406194 DOI: 10.2174/1871520611009030250] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 02/10/2010] [Indexed: 11/22/2022]
Abstract
Patients with well-differentiated neuroendocrine tumours of the gastrointestinal tract often present with metastases and hormonal symptoms. These patients can be palliated by interventional tumour reduction and medical treatment with somatostatin analogues; no effective chemotherapy is available. Radionuclide therapy via somatostatin receptors is one new therapeutic alternative. The recognition that neuroendocrine tumours express specific receptors for growth factors and chemokines, which are of importance for tumour growth, vascularization, and spread, may open the way for new therapeutic approaches. The signalling pathways in carcinoid tumours are incompletely explored. This review summarizes potential new treatment strategies from clinical and experimental studies, e.g. inhibition of angiogenesis, targeting of growth factors or their receptors by tyrosine kinase inhibitors, interference with specific cellular pathways (mTOR, PI3K, RAS/RAF, Notch), and also inhibition of the proteasome and histone deacetylation. Combining targeted therapy with chemotherapy, or using drugs to sensitize for radionuclide therapy, may enhance the treatment outcome.
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Lagerstrand KM, Vikhoff-Baaz B, Starck G, Forssell-Aronsson E. Contrast agent influences MRI phase-contrast flow measurements in small vessels. Magn Reson Med 2010; 64:42-6. [DOI: 10.1002/mrm.22368] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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79
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Starck G, Vkhoff-Baaz B, Ljungberg M, Malmgren K, Forssell-Aronsson E, Jönsson L, Ekholm S. Anterior to posterior hippocampal MRS metabolite difference is mainly a partial volume effect. Acta Radiol 2010; 51:351-9. [PMID: 20201639 DOI: 10.3109/02841850903540401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The concentration of N-acetylaspartate (NAA) in hippocampus, as measured with magnetic resonance spectroscopy (MRS), and the ratio of NAA/(choline (Cho) + creatine (Cr)) are valuable tools in the lateralization of temporal lobe epilepsy (TLE). MRS of hippocampus is also increasingly used to study certain psychiatric and degenerative diseases. However, the reliability of such measurements of hippocampus has been questioned. PURPOSE To re-evaluate MRS imaging data from prior control subjects with regard to variation of metabolite concentrations in hippocampus from anterior to posterior and the partial volume (R)contribution to the measurements from adjacent tissue. MATERIAL AND METHODS Twelve healthy subjects, mean age 33 years, were studied with MRS imaging. The measurement volume was angled along the temporal horns and metabolite concentration images were reconstructed at the MR system. Regions of interest (ROIs) in the anterior, medial, and posterior parts of both hippocampi were evaluated. Signal normalization to the total MRS signal from all ROIs permitted pooling of individual data with different and unknown signal scaling. One subject was re-examined with a high resolution three-dimensional (3D) volume of the brain for evaluation of partial volumes in the MRS examination. RESULTS Overall, there were significantly lower concentrations of NAA in the anterior parts, and of (Cho+Cr) in the posterior parts, while the NAA/(Cho+Cr) ratio in the posterior parts of the mesial temporal lobes was significantly higher. Hippocampus accounted for one-half, one-third, and one-quarter of the anterior, middle, and posterior ROIs, respectively. The NAA/(Cho+Cr) ratio thus showed a reverse relationship to the relative volume of hippocampal tissue within the ROI. CONCLUSION Metabolite concentrations in the mesial temporal lobe obtained with MRS imaging represent the mean value of hippocampus and a considerable amount of adjacent tissue. To assess the hippocampus alone, an actual voxel well below 1 cm(3) and a sub-centimeter slice thickness are required.
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Uusijärvi H, Chouin N, Bernhardt P, Ferrer L, Bardiès M, Forssell-Aronsson E. Comparison of Electron Dose-Point Kernels in Water Generated by the Monte Carlo Codes, PENELOPE, GEANT4, MCNPX, and ETRAN. Cancer Biother Radiopharm 2009; 24:461-7. [DOI: 10.1089/cbr.2008.0573] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Forssell-Aronsson E, Kjellén E, Mattsson S, Hellström M, Swedish Cancer Society Investigatio T. Medical Imaging for Improved Tumour Characterization, Delineation and Treatment Verification. Acta Oncol 2009; 41:604-614. [PMID: 28758870 DOI: 10.1080/028418602321028201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In an investigation by the Swedish Cancer Society, the present status, critical issues and future aspects and potentials were described by an expert group for each of nine major areas of radiation therapy research. This report deals with medical imaging for improved medical diagnosis including tumour detection, staging and characterization, treatment planning, guiding and verification, evaluation of response and treatment follow-up.
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Carlsson J, Forssell-Aronsson E, Glimelius B, Swedish Cancer Society Investigatio T. Radiation Therapy Through Activation of Stable Nuclides. Acta Oncol 2009; 41:629-634. [PMID: 28758862 DOI: 10.1080/028418602321028238] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In an investigation by the Swedish Cancer Society, an expert group described the present status, critical issues and future aspects and potentials for each of nine major areas of radiation therapy research. This report deals with radiation therapy using activation of stable nuclides.
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Mehrara E, Forssell-Aronsson E, Ahlman H, Bernhardt P. Quantitative analysis of tumor growth rate and changes in tumor marker level: specific growth rate versus doubling time. Acta Oncol 2009; 48:591-7. [PMID: 19330565 DOI: 10.1080/02841860802616736] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Doubling time (DT) of tumor volume has been widely used to estimate the growth rate of tumors. However, DT gives incorrect estimates of the average growth rate of tumors when the uncertainty of growth rate is considerable. Specific growth rate (SGR) is less affected by uncertainties and is a more relevant parameter. Optimized imaging techniques and prolonged interval between observations can reduce the uncertainty of growth rate estimation. DT is also used for defining changes in tumor marker level. The aim of this study was to compare DT and SGR as measures of growth rate when the uncertainty is negligible. METHODS Mathematical analysis and computer simulations were carried out assuming no uncertainty of growth rate estimation. Data from two previously published clinical studies were assessed by both variables. RESULTS Due to the non-linear relationship between DT and SGR, using these variables does not give similar results. The variation of DT is not uniformly indicating variations of the growth rate. DT largely overestimates the difference in growth rate of slowly growing tumors and underestimates the difference in growth rate of rapidly growing tumors. On the other hand, SGR uniformly indicates the difference between growth rates throughout all ranges. Quantitative analysis of clinical observations can lead to contradictory results depending on the variable used for growth rate. CONCLUSION The growth rate of tumor volume should be expressed by SGR, or percentage increase per unit time, regardless of the level of the uncertainty of growth rate estimation. This conclusion is also valid for changes in tumor marker level, whether it is correlated with the growth rate of tumor volume or not.
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Mattsson S, Brahme A, Carlsson J, Denekamp J, Forssell-Aronsson E, Hellström M, Johansson KA, Kjellén E, Littbrand B, Nordenskjöld B, Stenerlöw B, Turesson I, Zackrisson B, Glimelius B. Swedish Cancer Society Radiation Therapy Research Investigation. Acta Oncol 2009; 41:596-603. [PMID: 28758858 DOI: 10.1080/028418602321028193] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In an investigation by the Swedish Cancer Society, the present status, critical issues and future aspects and prospects were described by an expert group for each of nine major areas of radiation research. A summary of the investigation is presented in this report. A more extensive summary (in Swedish) can be found at www.Cancerfonden.se. It is concluded that radiation therapy plays an increasingly important role in curative and palliative tumour treatment and presents a considerable challenge to research. Several suggestions are made that could improve the possibilities for high-quality radiation therapy research in Sweden.
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Carlsson J, Forssell-Aronsson E, Glimelius B, Mattsson S, Swedish Cancer Society Investigatio T. Therapy with Radiopharmaceuticals. Acta Oncol 2009; 41:623-628. [PMID: 28758863 DOI: 10.1080/028418602321028229] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In an investigation by the Swedish Cancer Society, an expert group described the present status, critical issues and future aspects and potentials for each of nine major areas of radiation therapy research. The present report deals with therapy with radiopharmaceuticals.
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Lagerstrand KM, Plewes DB, Vikhoff-Baaz B, Forssell-Aronsson E. Flow-induced disturbances in balanced steady-state free precession images: means to reduce or exploit them. Magn Reson Med 2009; 61:893-8. [PMID: 19191282 DOI: 10.1002/mrm.21656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this work computer simulations and phantom measurements are presented that show the effect of flow on in-plane balanced steady-state free precession images. The images were studied for various flow velocities, excitation regions, relaxation times, RF-pulse angles, and off-resonance frequencies. The work shows that flow-induced disturbances are present in the images, but can be reduced by the application of inhomogeneous excitation regions. Also, a velocity quantification method that utilizes the disturbances was developed and proved to quantify flow velocities accurately. The work concluded that the flow-induced disturbances can be reduced to improve image quality, but can also be exploited to quantify the flow velocity.
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Lundh C, Lindencrona U, Postgård P, Carlsson T, Nilsson M, Forssell-Aronsson E. Radiation-induced thyroid stunning: differential effects of (123)I, (131)I, (99m)Tc, and (211)At on iodide transport and NIS mRNA expression in cultured thyroid cells. J Nucl Med 2009; 50:1161-7. [PMID: 19525464 DOI: 10.2967/jnumed.108.061150] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Recent clinical and experimental data demonstrate that thyroid stunning is caused by previous irradiation and may influence the efficacy of (131)I radiation therapy of thyroid cancer and possibly hyperthyroidism. To avoid stunning, many clinics have exchanged (131)I for (123)I for pretherapeutic diagnostic imaging and dose planning. Furthermore, recent in vitro studies indicate that (131)I irradiation reduces iodide uptake by downregulating the expression of the sodium iodide symporter (NIS). The rationale for this study was therefore to study effects on iodide transport and NIS messenger RNA (mRNA) expression in thyrocytes exposed to both (123)I and (131)I in addition to some other potentially interesting radionuclides. METHODS Thyrotropin-stimulated thyroid cell monolayers were exposed to 0.5 Gy of (123)I, (131)I, (99m)Tc, or (211)At, all being radionuclides transported via NIS, in the culture medium for 6 h, or to various absorbed doses of (123)I or (131)I for 48 h. NIS mRNA expression was analyzed using quantitative reverse-transcriptase polymerase chain reaction. RESULTS Iodide transport and NIS mRNA expression were reduced by all radionuclides. At the same absorbed dose, iodide transport was reduced the most by (211)At, followed by (123)I and (99m)Tc (equally potent), whereas (131)I was least effective. The onset of NIS downregulation was rapid (<1 d after irradiation) in cells exposed to (123)I or (211)At and was delayed in cells irradiated with (131)I or (99m)Tc. Iodide transport and NIS expression were recovered only for (211)At. (123)I reduced the iodine transport and the NIS mRNA expression more efficiently than did (131)I at an equivalent absorbed dose, with a relative biological effectiveness of about 5. CONCLUSION The stunning effect per unit absorbed dose is more severe for (123)I than for (131)I. Despite the lower absorbed dose per unit activity for (123)I than for (131)I, stunning by (123)I cannot be excluded in patients. The degree to which iodide transport capacity and NIS mRNA expression are reduced seems to be related to the biological effectiveness of the type of radiation delivering the absorbed dose to the target, with (211)At (which has the highest relative biological effectiveness) causing the highest degree of stunning per unit absorbed dose in the present study.
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Starck G, Carlsson A, Ljungberg M, Forssell-Aronsson E. k-space analysis of point-resolved spectroscopy (PRESS) with regard to spurious echoes in in vivo (1)H MRS. NMR IN BIOMEDICINE 2009; 22:137-147. [PMID: 18759377 DOI: 10.1002/nbm.1289] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The spurious echo artefact, not uncommon in (1)H MRS in the brain, comes from refocusing outer volume signal. Application of MRS in small volumes in susceptibility-affected regions often results in large shim gradients. The artefact problem is accentuated when the global effect of the shim gradient shifts the water resonance outside the water suppression band in the outer volume. This scenario brings the issue of spurious echoes once again to the fore. In this paper, spurious signals of the point-resolved spectroscopy (PRESS) sequence are analysed using the concept of k-space. This new approach facilitates a more geometrical view of the problem, well suited for studying the effect of gradient spoiling and refocusing of signal. Several spoiling options are shown, and the probability of the global effects of shimming being a primary cause of the artefact is discussed. Fourier transform analysis of realistic slice profiles, combined with the k-space description of spurious echoes, shows that unsuppressed water signal in outer regions greatly increases the demands on spoiling. Gradient spoiling adequate for artefact suppression at a given size of MRS volume may not be sufficient at a smaller size. Several ways to improve PRESS measurements with regard to suppression of spurious signal are discussed.
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Uusijärvi H, Bernhardt P, Forssell-Aronsson E. Tumour control probability (TCP) for non-uniform activity distribution in radionuclide therapy. Phys Med Biol 2008; 53:4369-81. [PMID: 18660558 DOI: 10.1088/0031-9155/53/16/010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Non-uniform radionuclide distribution in tumours will lead to a non-uniform absorbed dose. The aim of this study was to investigate how tumour control probability (TCP) depends on the radionuclide distribution in the tumour, both macroscopically and at the subcellular level. The absorbed dose in the cell nuclei of tumours was calculated for (90)Y, (177)Lu, (103m)Rh and (211)At. The radionuclides were uniformly distributed within the subcellular compartment and they were uniformly, normally or log-normally distributed among the cells in the tumour. When all cells contain the same amount of activity, the cumulated activities required for TCP = 0.99 ((approximate)A(TCP=0.99)) were 1.5-2 and 2-3 times higher when the activity was distributed on the cell membrane compared to in the cell nucleus for (103m)Rh and (211)At, respectively. TCP for (90)Y was not affected by different radionuclide distributions, whereas for (177)Lu, it was slightly affected when the radionuclide was in the nucleus. TCP for (103m)Rh and (211)At were affected by different radionuclide distributions to a great extent when the radionuclides were in the cell nucleus and to lesser extents when the radionuclides were distributed on the cell membrane or in the cytoplasm. When the activity was distributed in the nucleus, (approximate)A(TCP=0.99) increased when the activity distribution became more heterogeneous for (103m)Rh and (211)At, and the increase was large when the activity was normally distributed compared to log-normally distributed. When the activity was distributed on the cell membrane, (approximate)A(TCP=0.99) was not affected for (103m)Rh and (211)At when the activity distribution became more heterogeneous. (approximate)A(TCP=0.99) for (90)Y and (177)Lu were not affected by different activity distributions, neither macroscopic nor subcellular.
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Swärd C, Bernhardt P, Johanson V, Schmitt A, Ahlman H, Stridsberg M, Forssell-Aronsson E, Nilsson O, Kölby L. Comparison of [177Lu-DOTA0,Tyr3]-Octreotate and [177Lu-DOTA0,Tyr3]-Octreotide for Receptor-Mediated Radiation Therapy of the Xenografted Human Midgut Carcinoid Tumor GOT1. Cancer Biother Radiopharm 2008; 23:114-20. [DOI: 10.1089/cbr.2007.0421] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Bernhardt P, Forssell-Aronsson E. Estimation of metastatic cure after radionuclide therapy. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF... 2007; 51:297-303. [PMID: 17464278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Targeted radionuclide therapy of disseminated tumor disease involves many factors that will affect the therapeutic outcome. For optimization of such therapy, it is important to know how these factors affect the therapeutic outcome. In this paper, the metastatic cure probability (MCP) model is described. The MCP model is a valuable tool for analyses of the various factors influencing the metastatic cure. The factors discussed are: 1) the physical parameters (the energy and range of emitted particles, absorbed dose-distributions, and cross-irradiation of tumors from the surrounding normal tissue) and 2) the biological parameters (radiosensitivity of tumors, tumor distributions, tumor growth rate, metastasis formation rate, variable tumor activity concentration and non-homogeneous tumor activity distributions).
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Bernhardt P, Oddstig J, Kölby L, Nilsson O, Ahlman H, Forssell-Aronsson E. Effects of Treatment with 177Lu-DOTA-Tyr3-Octreotate on Uptake of Subsequent Injection in Carcinoid-Bearing Nude Mice. Cancer Biother Radiopharm 2007; 22:644-53. [DOI: 10.1089/cbr.2007.333] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Nordén MM, Larsson F, Tedelind S, Carlsson T, Lundh C, Forssell-Aronsson E, Nilsson M. Down-regulation of the Sodium/Iodide Symporter Explains 131I-Induced Thyroid Stunning. Cancer Res 2007; 67:7512-7. [PMID: 17671222 DOI: 10.1158/0008-5472.can-07-0823] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
(131)I radiation therapy of differentiated thyroid cancer may be compromised by thyroid stunning (i.e., a paradoxical inhibition of radioiodine uptake caused by radiation from a pretherapeutic diagnostic examination). The stunning mechanism is yet uncharacterized at the molecular level. We therefore investigated whether the expression of the sodium/iodide symporter (NIS) gene is changed by irradiation using (131)I. Confluent porcine thyroid cells on filter were stimulated with thyroid-stimulating hormone (TSH; 1 milliunit/mL) or insulin-like growth factor-I (IGF-I; 10 ng/mL) and simultaneously exposed to (131)I in the culture medium for 48 h, porcine NIS mRNA was quantified by real-time reverse transcription-PCR using 18S as reference, and transepithelial iodide transport was monitored using (125)I(-) as tracer. TSH increased the NIS expression >100-fold after 48 h and 5- to 20-fold after prolonged stimulation. IGF-I enhanced the NIS transcription at most 15-fold but not until 5 to 7 days. (131)I irradiation (7.5 Gy) decreased both TSH-stimulated and IGF-I-stimulated NIS transcription by 60% to 90% at all investigated time points. TSH and IGF-I stimulated NIS synergistically 15- to 60-fold after 5 days. NIS expression was reduced by (131)I also in costimulated cells, but the transcription level remained higher than in nonirradiated cells stimulated with TSH alone. Changes in NIS mRNA always correlated with altered (125)I(-) transport in cultures with corresponding treatments. It is concluded that down-regulation of NIS is the likely explanation of (131)I-induced thyroid stunning. Enhanced NIS expression by synergistically acting agents (TSH and IGF-I) partly prevents the loss of iodide transport expected from a given absorbed dose, suggesting that thyroid stunning might be pharmacologically treatable.
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Lindencrona U, Forssell-Aronsson E, Nilsson M. Transport of free 211At and 125I- in thyroid epithelial cells: effects of anion channel blocker 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid on apical efflux and cellular retention. Nucl Med Biol 2007; 34:523-30. [PMID: 17591552 DOI: 10.1016/j.nucmedbio.2007.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 03/15/2007] [Accepted: 03/27/2007] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Astatine ((211)At; alpha-emitter; t(1/2)=7.21 h) shares several features with its halogen neighbour iodine. In the present study, we investigated whether 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) can be used to increase the cellular retention time of (211)At and radioiodide in thyroid epithelial cells. METHODS The transepithelial transport and cellular uptake of (211)At and (125)I(-) were studied simultaneously in porcine thyrocytes cultured in bicameral chambers. The cells were prestimulated with thyroid-stimulating hormone (TSH) or epidermal growth factor (EGF) for 48 h. In addition, the acute effects of DIDS and forskolin were investigated. RESULTS The transepithelial transport of both radionuclides was stimulated by TSH and down-regulated by EGF. DIDS rapidly reduced the efflux and increased the cellular content of (125)I(-) in control and TSH-stimulated cells, whereas DIDS had no effect on (125)I(-) transport in EGF-treated cells. DIDS blocked the (211)At efflux only in TSH-stimulated cells. Unexpectedly, DIDS caused an accelerated efflux of (211)At in both control and EGF-stimulated cells and, furthermore, reduced the cellular content of (211)At in the EGF-stimulated cultures. DIDS had no effect on the forskolin-induced efflux of the two radionuclides. CONCLUSIONS The magnitude of thyroidal (211)At uptake and efflux is similar to that of (125)I(-), strongly dependent on the functional activity of the cells. However, (211)At efflux likely involves several permeating mechanisms with different sensitivity to DIDS, which are at least partly not shared by (125)I(-). The results suggest that anion channel blockage is potentially useful to increase the absorbed dose from both (211)At and radioiodine in NIS-expressing tumours.
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Mehrara E, Forssell-Aronsson E, Ahlman H, Bernhardt P. Specific growth rate versus doubling time for quantitative characterization of tumor growth rate. Cancer Res 2007; 67:3970-5. [PMID: 17440113 DOI: 10.1158/0008-5472.can-06-3822] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Doubling time (DT) is widely used for quantification of tumor growth rate. DT is usually determined from two volume estimations with measurement time intervals comparable with or shorter than DT. Clinical data show that the frequency distribution of DT in patients is positively skewed, with some very long DT values compared with the average DT. Growth rate can also be quantified using specific growth rate (SGR; %/d), equal to ln2/DT. The aim of this work was to compare DT and SGR as growth rate variables. Growth rate calculations were computer simulated for a tumor with DT of 100 days, measurement time interval of 1 to 200 days, and volume estimation uncertainty of 5% to 20%. Growth rate variables were determined and compared for previously published clinical data. The study showed that DT is not a suitable variable for tumor growth rate because (a) for short measurement time intervals, or high volume uncertainties, mean DT can either overestimate or underestimate the average growth rate; (b) DT is not defined if the consecutively estimated volumes are equal; and (c) the asymmetrical frequency distribution of DT makes it unsuitable for common statistical testing. In contrast, mean SGR and its equivalent DT give the correct values for average growth rate, SGR is defined for all tumor volume changes, and it has a symmetrical frequency distribution. SGR is also more accurate to use when discussing, for example, growth fraction, cell loss rate, and growth rate heterogeneities within the tumor. SGR should thus be used, instead of DT, to quantify tumor growth rate.
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Uusijärvi H, Bernhardt P, Forssell-Aronsson E. Translation of Dosimetric Results of Preclinical Radionuclide Therapy to Clinical Situations: Influence of Photon Irradiation. Cancer Biother Radiopharm 2007; 22:268-74. [PMID: 17600475 DOI: 10.1089/cbr.2006.317] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The radionuclide evaluation for therapy starts with preclinical studies in, for example, mice and rats, and various radionuclides have shown promising results. However, many radionuclides emit photons that will irradiate normal tissues. The risk of normal tissue toxicity in patients (e.g., bone marrow suppression) may be underestimated when relying on preclinical results. To illustrate the influence of photons in preclinical and clinical trials, the ratio between the tumor-to-normal tissue absorbed-dose rate ratio (TND) was calculated for humans, rats, and mice for 111In, 125I, 67Ga, 90Y, 131I, and 177Lu. The normal tissues were simulated by 70-kg, 300-g, and 20-g ellipsoids for humans, rats, and mice, respectively. It was assumed that the radionuclides were uniformly distributed, and that the activity concentration was 25 times higher in the tumor than in the normal tissue. There were only small differences between the TND values for the different species for 90Y and 177Lu. 131I showed similar TND values for rats and mice, whereas they were lower for humans. For 111In, 125I, and 67Ga, however, there were large differences between the different species. The influence of photons may thus be much lower in preclinical studies than in clinical situations. Therefore, translations of absorbed doses from animals to humans must be performed with caution.
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Lundh C, Nordén MM, Nilsson M, Forssell-Aronsson E. Reduced iodide transport (stunning) and DNA synthesis in thyrocytes exposed to low absorbed doses from 131I in vitro. J Nucl Med 2007; 48:481-6. [PMID: 17332627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023] Open
Abstract
UNLABELLED Thyroid stunning refers to reduced uptake of (131)I in the thyroid tissue (or tumor) during radioiodine ((131)I) therapy compared with the uptake measured after the previous administration of (131)I for diagnostic purposes. The phenomenon is clinically important, as it can potentially lead to the undertreatment of thyroid cancer or to unnecessarily high absorbed doses in critical organs. Previous clinical and experimental studies indicated that thyroid stunning is absorbed dose dependent. The aim of this study was to investigate the effects of (131)I irradiation on (125)I(-) transport and cell proliferation at low absorbed doses in vitro. METHODS Primary cultured porcine thyroid cells were grown to form a confluent monolayer of epithelial cells on a filter in a bicameral culture system. The cells were continuously irradiated with (131)I in the culture medium for 48 h to obtain 0.0015-1.5 Gy. At 3 d after irradiation was stopped, the transepithelial iodide transport capacity was evaluated by measuring (125)I(-) transport from the basal chamber compartment to the apical chamber compartment. The effect of (131)I irradiation on DNA synthesis was estimated by pulse labeling with (3)H-thymidine of both subconfluent and confluent cells irradiated with up to 9 Gy. Total DNA content was measured to quantify cell numbers. RESULTS A statistically significant reduction in (125)I(-) transport was seen at absorbed doses of >or=0.15 Gy, with a 50% reduction at 1.5 Gy, compared with the results observed for nonirradiated control cells. (3)H-Thymidine incorporation was already statistically significantly reduced at absorbed doses of 0.01-0.1 Gy, but 0.15-0.3 Gy did not affect DNA synthesis. However, absorbed doses of >or=1 Gy again resulted in reduced DNA synthesis. A 50% reduction was obtained at 4 Gy. Total DNA measurements revealed a statistically significant reduction in cell numbers at 8 Gy. CONCLUSION The lowest absorbed dose from (131)I that reduced iodide transport was 0.15 Gy. Because stunning was found at low absorbed doses, it might occur for (131)I treatment not only of thyroid cancer but also of thyrotoxicosis. On the basis of differences in dose responses, radiation-induced thyroid stunning and cell cycle arrest may be independent phenomena.
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Uusijärvi H, Bernhardt P, Ericsson T, Forssell-Aronsson E. Erratum: “Dosimetric characterization of radionuclides for systemic tumor therapy: Influence of particle range, photon emission, and subcellular distribution” [Med. Phys. 33, 3260-3269 (2006)]. Med Phys 2007. [DOI: 10.1002/j.2473-4209.2007.tb00456.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Uusijärvi H, Bernhardt P, Ericsson T, Forssell-Aronsson E. Erratum: “Dosimetric characterization of radionuclides for systemic tumor therapy: Influence of particle range, photon emission, and subcellular distribution” [Med. Phys. 33, 3260-3269 (2006)]. Med Phys 2007. [DOI: 10.1118/1.2409237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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100
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Oddstig J, Bernhardt P, Nilsson O, Ahlman H, Forssell-Aronsson E. Radiation-induced up-regulation of somatostatin receptor expression in small cell lung cancer in vitro. Nucl Med Biol 2007; 33:841-6. [PMID: 17045163 DOI: 10.1016/j.nucmedbio.2006.07.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 07/20/2006] [Accepted: 07/27/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND The internalization of radiolabeled somatostatin analogs into tumor cells is of great importance for radionuclide therapy. It has previously been shown that some radiolabeled somatostatin analogs are internalized through receptor-mediated endocytosis. The development of methods that increase the number of receptors on tumor cells is important to further improve the internalization of radionuclides. The aim of this study was to investigate the possibility of inducing up-regulation of the somatostatin receptor (sstr) expression on tumor cells by external-beam irradiation. METHODS Human small cell lung cancer (SCLC) cells were irradiated to absorbed doses of 2-8 Gy, and the uptake of 177Lu-DOTA-Tyr3-octreotate was measured 1-7 days after irradiation. The sstr2 mRNA expression was determined by quantitative reverse transcriptase-polymerase chain reaction. RESULTS The uptake of 177Lu-DOTA-Tyr3-octreotate was 1.5-3 times higher in cells irradiated to 4 Gy than in nonirradiated cells, and the highest uptake occurred 1 and 3-5 days after irradiation. The uptake of 177Lu-DOTA-Tyr3-octreotate was similar for cells irradiated to 2, 4, 6 and 8 Gy. The sstr2 mRNA expression was twice as high in the cells irradiated to 4 Gy than in the nonirradiated cells. CONCLUSIONS The uptake of 177Lu-DOTA-Tyr3-octreotate increased in SCLC cells after exposure to irradiation, probably due to up-regulation of sstr expression. These results may be important in optimizing the treatment of tumors expressing sstr using radiolabeled somatostatin analogs.
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