Papers by Bieke Van Den Bossche
Veterinary Radiology <html_ent glyph="@amp;" ascii="&"/> Ultrasound, 2005
Scintigraphy (positron emission tomography (PET) or single photon emission computed tomography (S... more Scintigraphy (positron emission tomography (PET) or single photon emission computed tomography (SPECT) techniques) allows qualitative and quantitative measurement of physiologic processes as well as alterations secondary to various disease states. With the use of specific radioligands, molecular pathways and pharmacokinetic processes can be investigated. Radioligand delivery can be (semi)quantified in the region of interest in cross-sectional and longitudinal examinations, which can be performed under the same conditions or after physiologic or pharmacologic interventions. Most preclinical pharmacokinetic studies on physiological and experimentally altered physiological processes are performed in laboratory animals using high-resolution imaging systems. Single photon emission imaging has the disadvantage of decreased spatial and temporal resolution compared with PET. The advantage of SPECT is that equipment is generally more accessible and commonly used radionuclides have a longer physical half-life allowing for investigations over a longer time interval. This review will focus on single photon emission scintigraphy. An overview of contemporary techniques to measure biodistribution and kinetics of radiopharmaceuticals in small animal in vivo is presented. Theoretical as well as practical aspects of planar c camera and SPECT pinhole (PH) imaging are discussed. Current research is focusing on refining PH SPECT methodology, so specific regarding technical aspects and applications of PH SPECT will be reviewed.
The Journal of Nuclear Medicine, 2006
In vitro assessment of hormone receptor status using a ligandbinding assay or immunohistochemistr... more In vitro assessment of hormone receptor status using a ligandbinding assay or immunohistochemistry in breast cancer patients predicts endocrine responsiveness with an accuracy of only 60%-70%. Assessment of an end product of estrogen receptor stimulation, such as the progesterone receptor, is assumed to provide a measure of functional receptor content and has proven to increase predictive accuracy. In analogy with the estrogen-dependent regulation of somatostatin receptor (SSTR) expression in endocrine-responsive human breast cancer cell lines, efficient antiestrogen treatment in patients may result in a downregulation of SSTR at the cell surface in breast tumors. In vivo imaging of this molecular event by means of sequential 99m Tc-depreotide scintigraphy could enable selection of breast cancer patients susceptible to endocrine therapy. Methods: Twenty patients with a diagnosis of advanced breast cancer in whom first-or second-line hormonal therapy was going to be initiated were included. Patients underwent sequential 99m Tcdepreotide scintigraphy before and 3 wk after initiating hormonal treatment. Follow-up data were retrieved from routine clinical evaluation by means of physical examination, imaging (e.g., bone scan, CT, MRI) and blood analysis. Lesion-to-background ratios (L/BGs) were calculated on planar and SPECT images and a change of .25% between the baseline and follow-up scan was considered significant. Results: At 6 mo after initiation of treatment, 8 patients had stable disease and were considered to be responding to hormonal treatment, whereas 10 patients had progressive disease and were considered to be nonresponders. The positive and negative predictive values of baseline 99m Tc-depreotide scintigraphy for endocrine responsiveness were 73% (8/11) and 100% (7/7), respectively. Sequential scans were always both positive or both negative. The relative change in 99m Tc-depreotide uptake between sequential scans significantly differed in responders compared with nonresponders (P5 0.017)uptake decreased in the first group and increased in the latter. As such, baseline 99m Tc-depreotide scintigraphy combined with the changes in tracer uptake between the baseline and follow-up scan predicted endocrine responsiveness with an accuracy of 100%. Conclusion: Sequential 99m Tc-depreotide scintigraphy could allow for separation of responders and nonresponders immediately or as early as 3 wk after initiation of treatment.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2006
In vitro assessment of hormone receptor status using a ligand-binding assay or immunohistochemist... more In vitro assessment of hormone receptor status using a ligand-binding assay or immunohistochemistry in breast cancer patients predicts endocrine responsiveness with an accuracy of only 60%-70%. Assessment of an end product of estrogen receptor stimulation, such as the progesterone receptor, is assumed to provide a measure of functional receptor content and has proven to increase predictive accuracy. In analogy with the estrogen-dependent regulation of somatostatin receptor (SSTR) expression in endocrine-responsive human breast cancer cell lines, efficient antiestrogen treatment in patients may result in a downregulation of SSTR at the cell surface in breast tumors. In vivo imaging of this molecular event by means of sequential (99m)Tc-depreotide scintigraphy could enable selection of breast cancer patients susceptible to endocrine therapy. Twenty patients with a diagnosis of advanced breast cancer in whom first- or second-line hormonal therapy was going to be initiated were included...
Veterinary Radiology <html_ent glyph="@amp;" ascii="&"/> Ultrasound, 2005
Scintigraphy (positron emission tomography (PET) or single photon emission computed tomography (S... more Scintigraphy (positron emission tomography (PET) or single photon emission computed tomography (SPECT) techniques) allows qualitative and quantitative measurement of physiologic processes as well as alterations secondary to various disease states. With the use of specific radioligands, molecular pathways and pharmacokinetic processes can be investigated. Radioligand delivery can be (semi)quantified in the region of interest in cross-sectional and longitudinal examinations, which can be performed under the same conditions or after physiologic or pharmacologic interventions. Most preclinical pharmacokinetic studies on physiological and experimentally altered physiological processes are performed in laboratory animals using high-resolution imaging systems. Single photon emission imaging has the disadvantage of decreased spatial and temporal resolution compared with PET. The advantage of SPECT is that equipment is generally more accessible and commonly used radionuclides have a longer physical half-life allowing for investigations over a longer time interval. This review will focus on single photon emission scintigraphy. An overview of contemporary techniques to measure biodistribution and kinetics of radiopharmaceuticals in small animal in vivo is presented. Theoretical as well as practical aspects of planar c camera and SPECT pinhole (PH) imaging are discussed. Current research is focusing on refining PH SPECT methodology, so specific regarding technical aspects and applications of PH SPECT will be reviewed.
Nuclear Medicine Communications, 2004
The purpose of this study was to determine the potential role of Tc depreotide scintigraphy for t... more The purpose of this study was to determine the potential role of Tc depreotide scintigraphy for the evaluation of bone metastases compared with Tc methylenediphosphonate (MDP) bone scintigraphy and for the prediction of treatment response in breast cancer patients in whom first- or second-line hormonal therapy was to be initiated. Twelve patients with a diagnosis of advanced breast cancer were included. All patients underwent both a bone scan and a depreotide scan and at least one other conventional imaging procedure, including plain film radiography (n=11), computed tomography (n=6) or magnetic resonance imaging (n=5), for confirmation of metastatic disease. The mean time interval between the bone scan and the depreotide scan was 30.6 days. Follow-up data were retrieved from routine clinical evaluation by means of physical examination, imaging and blood analysis. On a patient basis we found a sensitivity, specificity and accuracy of, respectively 100%, 50% and 83.3% for the bone scan and 62.5%, 100% and 75% for the depreotide scan in the diagnosis of bone metastasis. In eight patients with available follow-up data two with a positive depreotide scan remained stable and five of six patients with a negative depreotide scan had progressive disease. In this small series of breast cancer patients Tc depreotide scintigraphy proves less sensitive but more specific as compared to Tc-MDP bone scintigraphy in measuring the extent of bone metastasis. On the other hand Tc depreotide scintigraphy elucidates, non-invasively, tumour characteristics and may be indicative for prognosis and response to hormonal treatment.
Journal of Clinical Oncology, 2004
To date, our understanding of the role of receptors and their cognate ligands in cancer is being ... more To date, our understanding of the role of receptors and their cognate ligands in cancer is being successfully translated into the design and development of an arsenal of new, less toxic, and more specific anticancer drugs. Because most of these novel drugs are cytostatic, objective response as measured by morphologic imaging modalities (eg, computed tomography or magnetic resonance imaging) cannot be used as a surrogate marker for drug development or for clinical decision making. Positron emission tomography (PET) can be used to image and quantify the in vivo distribution of positron-emitting radioisotopes such as oxygen-15, carbon-11, and fluorine-18 that can be substituted or added into biologically relevant and specific receptor radioligands. Similarly, single-photon emission computed tomography (SPECT) can be used to image and quantify the in vivo distribution of receptor targeting compounds labeled with indium-111, technetium-99m, and iodine-123. By virtue of their whole-body imaging capacity and the absence of errors of sampling and tissue manipulation as well as preparation, both techniques have the potential to address locoregional receptor status noninvasively and repetitively. This article reviews available data on the in vivo evaluation of receptor systems by means of PET or SPECT for identifying and monitoring patients with sufficient receptor overexpression for tailored therapeutic interventions, and also for depicting tumor tissue and determining the currently largely unknown heterogeneity in receptor expression among different tumor lesions within and between patients.
Cancer biotherapy & radiopharmaceuticals, 2004
This paper reports on the biodistribution and dosimetry of (99m)Tc-depreotide in patients. Whole ... more This paper reports on the biodistribution and dosimetry of (99m)Tc-depreotide in patients. Whole body planar images were acquired 30 minutes, 1, 2, 4, 9, and 24 hours after intravenous injection of 555-740MBq (99m)Tc-depreotide in 5 breast cancer patients. Urine was collected up to 24 hours after injection, allowing for a calculation of renal clearance and an interpretation of whole body clearance. Time activity curves were generated for the thyroid, lungs, liver, spleen, kidneys, colon, thoracic vertebrae/sternum, and whole body by fitting the organ-specific geometric mean counts, obtained from regions of interest (ROIs). The Medical Internal Radiation Dose (MIRD) formulation was applied to calculate the absorbed radiation dose for various organs. The whole body images show most of the activity distributed in the liver, spleen, and kidneys. Nearly all excretion of activity occurred by the renal system, and hepatobiliary excretion was negligible. Elimination of administered activity...
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Papers by Bieke Van Den Bossche