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K Scheidhauer

Publications and source records attributed to K Scheidhauer.

At least 55 records · Page 3Linked to original sources
PubMed1995

Presurgical visualization of primary breast carcinoma with PET emission and transmission imaging.

UNLABELLED: The aim of this study was to investigate a technique that visualizes findings from PET images in a context useful for surgery. METHODS: Simultaneously acquired PET emission and transmission scans were used. By applying a multipurpose imaging, registration and rendering tool (MPM), displays of orthogonal and volume-rendered views or any combination thereof were obtained. The PET emission and transmission scans were acquired under routine conditions. The final user-customized display (with a combination of orthogonal cuts and rendered views) was processed in 10 min or less on commercially available hardware. Distinct features of the body shape were clearly visible on the volume-rendered transmission views. Hot spots, e.g., in primary breast cancer, from the emission scans could be easily assessed in their localization relative to the body outline. CONCLUSION: Rendering of the main signatures in a single comprehensive display makes this method potentially valuable for simple presurgical workup and therapeutic management of breast cancer.

Breast Neoplasms↗
PubMed1995

[Biokinetics of tumor-affinity yttrium preparations--Part 1].

Differences of yttrium biokinetics after application to male tumor-bearing mice of 87Y-citrate were studied in comparison to a 87Y-NTA-EDTMP-Ca mixture after variation of both the manner of application (intraperitoneal vs. intratumoral) and the tumor type (mamma carcinoma vs. melanoma). The application of 87Y as NTA-EDTMP-Ca preparation led--in comparison to the citrate form applied so far--to a similar radionuclide tumor accumulation and distinctly lower extratumoral radioactivities in liver, spleen and skeleton with clearly more favorable tumor/background ratios. Melanomas showed a significantly higher radioactivity accumulation (factor 2-3) after injection of 87Y-NTA-EDTMP-Ca than mamma carcinomas. Intratumoral application led to high initial radioactivities in the tumors. Radioactivity concentrations which are comparable with those after intraperitoneal application were achieved within 4 h after intratumoral application. The application of the EDTMP-containing mixture promises in comparison to the traditional citrate form higher radiation doses in the tumor related to the whole-body radiation exposure. The consequences for a possible tumor therapy will be further investigated.

Animals↗
PubMed1994

High sensitivity of the in vivo detection of somatostatin receptors by 111indium (DTPA-octreotide)-scintigraphy in meningioma patients.

The recent availability of isotope-labelled somatostatin analogues has allowed one to detect somatostatin receptors in normal tissue as well as in endocrine or non-endocrine cranial tumours. The purpose of the present study was to establish the value of somatostatin receptor scintigraphy using an 111Indium-labelled somatostatin analogue, octreotide, in the diagnostic work-up of meningioma patients. Twenty-two patients (16 women, 6 men, aged from 19-70 years) with newly diagnosed, residual or recurrent cranial meningiomas were examined. 111Indium-labelled DTPA-octreotide was injected i.v.. Planar and tomographic images were obtained with a gamma camera 4-6, and 24 hours after injection. In all of the meningiomas studied a high density of somatostatin receptors was detected by scintigraphy. No false negative test result was found. Due to this, a 100% predictive value of a negative test was calculated. However, when the tumours were taken in culture differing staining intensity could be seen in the light- and electron microscopic level even on individual cells of a single culture when silver intensified somatostatin-gold was used as ligand. We conclude, that in vivo somatostatin receptor scintigraphy may aid in the pre-operative differential diagnosis of skull base tumours.

Adult↗
PubMed1994

111Indium (DTPA-octreotide) scintigraphy in patients with cerebral gliomas.

Somatostatin receptors (SR) have been identified in vitro in normal brain tissue, in neuro-endocrine tumours and in cerebral gliomas WHO grade 1 or 2 by autoradiography or using somatostatin-gold conjugates. In vivo, SR detection has become possible by scintigraphy applying the somatostatin analogue octreotide, radio-labelled with 111Indium. It was supposed that expression of SR in cerebral gliomas corresponds to low grade tumour malignancy and that, in vivo, somatostatin receptor scintigraphy (SRS) could refine and improve the WHO grading system for cerebral gliomas. Nineteen patients with cerebral gliomas (grade 2: n = 8, grade 3: n = 3, grade 4: n = 8) were examined with 111In (DTPA-octreotide) to evaluate, whether SRS could improve the pre-operative estimation of tumour biology and the postoperative management. The results of SRS were related with the histological findings and with the in vitro demonstration of somatostatin-binding sites on cultured tumour cells incubated with a somatostatin-gold conjugate. In vivo, none of the patients with glioma grade 2 showed enhanced tracer uptake in the SRS, whereas in vitro SR were detected in cultured tumour tissue in 5 out of 5 cases. Every patient with glioma grade 3 or 4 demonstrated a high focal uptake of 111In (DTPA-octreotide), as shown by SRS. Three patients with glioma grade 4, additionally examined with 99mTc-DTPA, showed an increased tracer uptake within the tumour area when compared with results of SRS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Magnetic resonance imaging in screening for bone metastasis? A prospective comparison with bone scintigraphy].

To define the value of magnetic resonance imaging (MRI) in screening for bone metastases (BM) compared to bone scintigraphy (BSc) 102 patients with tumours with frequent BM were examined also by MRI of spine, pelvis, femora, and proximal tibiae. All patients had normal BSc and 96 (94%) normal MRI. Only 6% of the patients had focal abnormalities within the bone marrow. This indicates that there is a 94% probability of absence of BM if BSc is normal. Therefore, BSc should currently remain the method of choice for screening for BM. Despite MRI is sensitive and specific, with the common technique up to now it should not be used instead of BSc in screening because of costs, duration, and lack of whole body examination. MRI is a valuable adjunct in equivocal findings in BSc with negative results on radiographs.

Bone Marrow↗
PubMed1993

[Radioiodine therapy in Europe--a survey].

Treatment with 131I is a well known and widely accepted therapy for benign thyroid disease and thyroid cancer. High dose 131I therapy for ablative reasons in well-differentiated thyroid cancer is done mostly in hospitals with controlled area and adequate equipment for radiation protection. Low-dose therapies, however, of hyperthyroidism, thyroid autonomy and goiter may be done in out-patients in many countries. Limits of radioactivity administered for an ambulant therapy are varying. In Germany, 131I therapy of out-patients is generally not permitted. As many patients are waiting for a therapy but capacity is too low, waiting lists up to several months exist. This leads to a kind of medical tourism into other countries where therapy of out-patients is possible. This is a crucial point with regard to optimal medical care as well to health economics. This paper presents the results of a questionnaire which was sent to the national EANM delegates of all European countries. There is a great variability among these countries which indicates the different views handling of radioactivity and radiation protection. A more detailed questionnaire about regulatory and administrative rules initiated by an EANM task group for risk assessment in nuclear medicine is on the way.

Ambulatory Care↗
PubMed1993

Somatostatin receptor scintigraphy in brain tumors and pituitary tumors: first experiences.

Somatostatin receptors have been demonstrated on various tumors of neuroendocrine and other origin. They have been detected in vitro by biochemical techniques as well as by autoradiography. The development of long-acting somatostatin analogs and the recent availability of radiolabeled octreotide have made the in vivo detection of somatostatin receptors possible. This preliminary study embraced 45 patients with meningiomas, brain tumors or pituitary tumors, which were imaged by planar and tomographic scintigraphy after intravenous injection of 111Indium-labeled octreotide. In all of the meningiomas studied (unifocal and multifocal tumors in various locations), a high density of somatostatin receptors was detected by scintigraphy. Pituitary tumors were slightly positive in 50% of cases only, independent of the endocrine activity. Gliomas with an intact blood-brain barrier showed no enhanced tracer uptake in vivo, while gliomas with disturbed blood-brain barrier had a high activity uptake. We conclude that in vivo somatostatin receptor scintigraphy, although not tumor-specific, may aid in the preoperative diagnosis and staging of intracranial tumors, especially skull base tumors.

Adult↗
PubMed1993

[Long term biokinetics of 169Yb following injection as citrate, hydroxyethylethylenediaminetetraacetate and nitrilotriacetate].

169Yb complexes with known biokinetics in tumour-bearing mice up to 48 h p.i. were injected into healthy mice to study the radionuclide biodistribution in various organs and tissues for 672 h after injection, in order to obtain reliable biokinetic data in an animal model, not affected by tumour-growth, as a basis for the calculation of biological half-life and dose distribution. The results demonstrated the existence of at least two components with different biological half-lives in the organs and tissues investigated. The effective half-lives of these components decreased with increasing stability of the complexes administered. The effective half-life of the fast component was a few hours and that of the slow one between about 200 and 800 h.

Animals↗
PubMed1991

Benzodiazepine receptors and cerebral blood flow in partial epilepsy.

It was the aim of this study to compare benzodiazepine (Bz) receptor binding and cerebral perfusion in patients with partial epilepsy. Single photon emission tomography (SPET) studies with the flow-marker technetium 99m hexamethylpropylene amine oxine (99mTc-HMPAO) and with the 123I-labelled Bz-receptor ligand Ro 16-0154 (123I-Iomazenil) were performed in 12 patients with partial epilepsy, all with normal magnetic resonance imaging (MRI) and computed tomography (CT) scans. The SPET studies with 123I-Iomazenil were carried out 5 min and 2 h after injection. At 2 h the distribution of activity was very similar to the expected distribution of Bz-receptors in the human brain, known from positron emission tomography (PET) work and post-mortem studies. Early images showed a significantly higher tracer accumulation in the area of the basal ganglia, cerebellum, and naso-pharyngeal space. This finding is caused by non-specific binding and the contribution of the tracer in the blood pool in this phase. Also after 2 h p.i. of 123I-Iomazenil, 9 of the 12 patients showed a focal decrease of of Bz-receptor binding. Ten patients had focal flow abnormalities with 99mTc-HMPAO SPET. In 8 subjects impairment of flow was seen in sites of reduced 123I-Iomazenil uptake. 123I-Iomazenil is suitable for Bz-receptor mapping. In this series of patients, Bz-receptor mapping with SPET seems to offer no advantage over 99mTc-HMPAO in the detection of epileptic foci.

Adult↗
PubMed1991

[Tumor scintigraphy using 123I-labeled estradiol in breast cancer--receptor scintigraphy].

The estrogen receptor (ER) status is an important factor for prognosis and endocrine therapy of breast cancer. Therefore 16-alpha-123I-iodoestradiol-17-beta (123I-E2) as a receptor-specific radiopharmacon was used for scintigraphic tumor detection in 62 patients suspected of breast cancer. The studies were performed as a multicenter trial (5 university hospitals) to validate the method and to overcome methodical problems. A fast tracer elimination from the blood pool into the liver was seen, followed by biliary excretion allowing early imaging of the thorax due to low background activity but resulting in difficult imaging conditions of the abdomen. In 42 patients (30 carcinomas, 12 benign lesions) the overall sensitivity was 66% (ER status cut-off: 10 fmol/mg). Some patients with breast cancer showed focal or diffuse uptake in the area of primary lymph drainage (parasternal, axillary) without any clinical correlation, demanding follow-up investigations. There was only one false-positive result in a receptor-negative primary carcinoma; thus, the non-invasive determination of the ER status seems to be feasible. The sensitivity of 123I-E2 in the detection of primary breast cancer or metastases and recurrences is low compared to mammography and other methods; therefore, 123I-E2 scintigraphy cannot be used as a screening method. Differentiation of malignant and benign tissue is even more difficult as both may have a positive ER status, for example in mastopathy. Nevertheless, 123I-E2 scintigraphy is an in vivo imaging technique for the detection of breast cancer depending on the ER status and provides information about tumor localisation. It may become a specific method for the non-invasive diagnosis of the ER status and may be helpful in follow-up studies. As a receptor-specific agent 123I-E2 may give answers to questions of tumor heterogeneity and changes of the ER status during therapy.

Aged↗
PubMed1990

[Immunoscintigraphy of the hematopoietic bone marrow in osteomyelofibrosis].

In planning the treatment of splenomegaly in primary or secondary osteomyelofibrosis it is necessary to know whether there is any significant hematopoiesis outside the spleen. In contrast to the measurement of iron kinetics with 59Fe, which is not suitable for imaging, immunoscintigraphy with the monoclonal antibody Bw 250/183 allows specific imaging of the hematopoietic bone marrow. The diagnostic use of this method in addition to iron kinetics is illustrated and discussed in a patient with primary osteomyelofibrosis.

Antibodies, Monoclonal↗
PubMed1989

[Tumor markers in malignant choroid melanoma].

Antibodies against tumor-associated antigens ("tumor markers") can be used for the diagnosis of malignant tumors. Eight different monoclonal antibodies, that can recognize tumor-associated antigens of dermal melanomas, were tested in cryostat sections of uveal melanomas. The uveal melanomas showed antigenic differences (e.g., gangliosides) and common antigens (e.g. high molecular weight melanoma-associated antigen) in comparison to dermal melanomas. The implications of these results for diagnosing and even treating uveal melanomas are discussed.

Alkaline Phosphatase↗
PubMed1988

Immunoscintigraphy in intraocular malignant melanoma.

Immunoscintigraphy of malignant tumours has become an encouraging tool in nuclear medicine. Early diagnosis of small lesions is mandatory for successful cancer therapy. The scintigraphic detectability of small lesions (less than 1 cm in diameter) by immunoscintigraphy is shown in 39 patients suffering from ocular tumours (37 malignant choroidal melanoma, two benign choroidal naevi) using 99Tcm-labelled F(ab')2 fragments of the anti-melanoma monoclonal antibody 225.28S; this antibody recognizes the high molecular weight melanoma-associated antigen. No adverse effects were observed. In terms of true-positive results, single photon emission computed tomography (SPECT) proved to be superior to planar scans (73% versus 41% true-positive results).

Aged↗
PubMed1987

[Radioimmunoscintigraphy with monoclonal antibodies].

Radioimmunoscintigraphy is presented as a new imaging modality in nuclear medicine, using specific antigen-antibody interactions. Monoclonal antibodies to tumor-associated antigens facilitate the characterization of molecular differences between tumors and normal cells. Labelled with gamma-emitting radioisotopes like I-131, I-123, In-111, and Tc99M, these antibodies can be used for in-vivo imaging. Radioimmunoscintigraphy does not compete with morphological modalities like CT and ultrasound, but provides additional information based on its functional principle. Hidden lesions may be detected. Target-to-background ratios, however, are still rather low hampering scintigraphic imaging. The use of Single Photon Emissions Computed Tomography (SPECT) in addition to planar scintigraphy resolves background activities thus providing better visualization and localization of tumors, and increasing sensitivity. The high cost of these time-consuming studies is still a limiting factor to its wider use. Its preliminary indication is founded on the suspicion of tumor progression, based on clinical findings and/or increasing serum tumor markers (CEA, CA 19-9, CA 12-5). This paper provides an overview over possible applications of radioimmunoscintigraphy. Its clinical use is demonstrated by studies of malignant melanoma, colorectal cancer and ovarian cancer.

Antibodies, Monoclonal↗
PubMed1986

[Nuclear magnetic resonance tomography of the orbits. Initial experiences using the paramagnetic contrast medium gadolinium-DTPA].

In 21 patients with orbital mass lesions MRI was performed before and after administration of paramagnetic contrast medium, Gadolinium-DTPA. In comparison to the plain scan the differentiation of the tumorous tissue against the surrounding structures was improved after application of contrast medium despite a partially moderate increase in signal intensity. Especially highly vascular tumors and vessel diseases show a significant contrast enhancement. With increasing experience in larger number of patients a tissue differentiation seems to be possible.

Adult↗