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S A Larsson

Publications and source records attributed to S A Larsson.

At least 37 records · Page 2Linked to original sources
PubMed1998

Accumulation of FDG in axillary sweat glands in hyperhidrosis: a pitfall in whole-body PET examination.

A diabetic male with severe autonomic neuropathy and recently discovered Hodgkin's disease demonstrated bilateral uptake of [2-18F]-2-fluoro-2-deoxy-d-glucose (FDG) in the axillary sweat glands during profuse sweating caused by hypoglycaemia at positron emission tomography examination. It is not yet clear whether the sweating interfered with the distribution of the radiopharmaceutical. Regardless of the cause or mechanism for the uptake, the finding is clinically relevant. A bilateral symmetrical accumulation of FDG in the axillae of a tumour patient does not necessarily indicate malignant involvement of the lymph nodes.

Adult↗
PubMed1998

Multidrug resistance phenotype in leukaemic cells from patients with acute myelocytic leukaemia can be detected with 99Tc(m)-MIBI.

The aim of the study was to investigate whether 99Tc(m)-MIBI (Cardiolite), recently shown to be a substrate for P-glycoprotein, has the potential to be used as a marker for mdr1 gene expression and whether cyclosporin A (CyA) can modify its accumulation in vivo. Leukaemic cells from ten patients with acute myelocytic leukaemia (AML) were used, five with undetectable mdr1 gene expression and five with mdr1 mRNA levels ranging from 1.0 to 3.8 mdr1 mRNA transcripts per cell. Cells were incubated with 99Tc(m)-MIBI, or with daunorubicin (Dnr), with and without 3 microM CyA. The median 99Tc(m)-MIBI accumulation (% of added radioactivity) in mdr1-negative cells was 0.89% and in the mdr1-positive cells 0.34%, P = 0.01. In mdr1-negative cells, the median increase in 99Tc(m)-MIBI accumulation with CyA was 30% compared with the mdr1-positive cells with a median increase of 242%, P = 0.009. CyA had no significant effect on Dnr accumulation in four of the mdr1-negative samples. The median increase of Dnr accumulation in the mdr1-positive cells was 40%. The results show that 99Tc(m)-MIBI with a high sensitivity can detect rather low levels of mdr1 gene expression in clinical samples. Consequently, 99T(c)m-MIBI scintigraphy has the potential to be used for monitoring the effect of resistance modifiers on the accumulation and retention of cytostatic drugs in human tumours in vivo.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Optimal design of planar-concave collimators for SPECT--an analytical approach.

In this paper we present an analytical tool for the design and optimization of planar-concave collimators for SPECT. We conclude that a single general planar-concave collimator that eliminates the non-isotropic blurring for all SPECT applications does not exist. On the other hand, it is possible to achieve pseudo-optimal collimators for different clinical applications by a careful choice of the design parameters. By classifying the clinical applications into two groups, for instance body and brain studies, the non-isotropic blurring for most SPECT situations may be dramatically reduced by means of planar-concave collimators. The results based on Monte Carlo simulations show that the shape of the point source response function of the reconstructed image obtained from the planar-concave collimator is more isotropic than that obtained from a conventional parallel-hole collimator. Specifically, the ratio of the FWHM of the reconstructed point response function in the radial and tangential direction is increased from 0.5 for the parallel-hole to 0.85 for the planar-concave collimator for sources 200 mm away from the centre of rotation.

Algorithms↗
PubMed1998

Feasibility and quality of biological banking of human normal and tumor tissue specimens as sources of DNA for the Malmö Diet and Cancer Study.

Human tumor and normal tissue specimens, which were collected from autopsy material 1-6 days postmortem, were compared with similar tissue specimens collected within 2 h after surgical resection and transport to the pathology department. The end point criteria used to evaluate the quality of the specimens for biological banking purposes were the extractability and yield of high molecular weight DNA and UV absorption ratios at 260:280 after collection and immediate storage of the specimens at -80 degrees C. The data demonstrated that autopsy material was a quality source of DNA, although of not such high quality as surgical biopsy specimens <2 h after resection. The advantages of using autopsy material to supplement surgical specimen collection sent to pathology, as opposed to using specimen collection at surgery wards or formalin-fixed material, as sources of DNA are: (a) large amounts of tumor and normal tissues from a variety of organ sites can be obtained without regard to the patient's health status; (b) a higher percentage of retrieval of incident cases of cancer in prospective designed trials is more likely to be achieved; and (c) the extractable DNA is of sufficiently high enough quality to permit direct analyses by molecular hybridization and sequence methodologies.

Autopsy↗
PubMed1997

Use of 99mTc-MIBI scintigraphy in the evaluation of the response of osteosarcoma to chemotherapy.

The use of gamma camera scintigraphy with technetium-99m hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) for assessment of the response of high-grade osteosarcoma to preoperative chemotherapy was evaluated. Twelve patients with osteosarcoma of the extremities underwent planar examination with 99mTc-MIBI before and after preoperative chemotherapy according to the recommendations of the Scandinavian Sarcoma Group. After calculating a quotient for the tumour and the average activity of both extremities and correcting for background activity, the change in uptake between the two examinations was assessed. This was compared with histological examination of the ultimately resected specimen in 11 patients and progressive clinical disease in one. All the 11 tumours undergoing histological examination showed cellular necrosis of between 50% and 100% as well as a reduced uptake of 99mTc-MIBI, while the single progressive tumour showed an increased uptake. There was a correlation between the reduction of radiopharmaceutical uptake and the histological response in the entire series, while the variation was too large to allow conclusions in individual patients. This variation may have biological reasons or may be due to the planar imaging technique, which only allows semiquantitative evaluation. The technique reflects response to therapy but is not yet clinically applicable for the identification of poor responders, which would serve as a basis for alteration of the chemotherapy regimen. In order to evaluate whether such a role could be fulfilled, further studies using single-photon emission tomography with correction for attenuation and scattering of photons are necessary.

Adolescent↗
PubMed1997

Alternative positron emission tomography with non-conventional positron emitters: effects of their physical properties on image quality and potential clinical applications.

The increasing amount of clinically relevant information obtained by positron emission tomography (PET), primarily with fluorine-18 labelled 2-deoxy-2-fluoro-D-glucose, has generated a demand for new routes for the widespread and cost-efficient use of positron-emitting radiopharmaceuticals. New dual-head single-photon emission tomography (SPET) cameras are being developed which offer coincidence detection with camera heads lacking a collimator or SPET imaging with specially designed collimators and additional photon shielding. Thus, not only satellite PET imaging units but also nuclear medicine units investing in these new SPET/PET systems need to examine all available alternatives for rational radionuclide supplies from host cyclotrons. This article examines 25 "alternative" positron-emitting radionuclides, discusses the impact of their decay properties on image quality and reviews methods for their production as well as for their application in imaging techniques.

Humans↗
PubMed1997

Evaluation of optimally designed planar-concave collimators in single-photon emission tomography.

The imaging properties of optimally designed planar-concave (PC) collimators were evaluated by means of Monte Carlo simulations. The evaluation was done with respect to total system spatial resolution and the overall image noise distribution in single-photon emission tomography. The results showed that the non-isotropy with PC collimators, assessed by the ratio of the full-width at half-maximum in the radial and tangential directions, was reduced by about 60% as compared with a conventional parallel-hole collimator for sources located 200 mm away from the centre of rotation. Furthermore, the image noise distribution along the object radius became more uniform when the curved collimator was used. The maximum increase in noise due to use of the curved collimator was about 45% close to the edge of the phantom, where the hole length was about 3 times longer. We also showed with Monte Carlo simulations that the spatial resolution of the lateral cortex when using the curved collimator was significantly improved due to improved radial resolution.

Algorithms↗
PubMed1997

Effect of food intake on liver and spleen volume: assessment with single photon emission computed tomography.

RATIONALE AND OBJECTIVES: The authors evaluated the influence of food intake on liver and spleen size. The rationale was that since a meal induces a marked increase in splanchnic blood flow, organ volume might also be affected. This could influence conclusions made at clinical examination. METHODS: Single photon emission computed tomography (SPECT) was performed in 20 healthy volunteers after administration of technetium-99m albumin colloid before and after ingestion of a standardized meal. A semiautomatic technique was used to determine liver and spleen size. RESULTS: There was a nonsignificant reduction in liver volume of 1.5% (P = .063) and a significant reduction in spleen volume of 3.2% (P = .00033) after food intake. CONCLUSION: Liver and spleen volume are marginally affected by food intake, and the changes are within the methodologic error of radiologic modalities.

Eating↗
PubMed1997

Detection of extrathoracic manifestations in sarcoidosis with somatostatin analogue scintigraphy.

BACKGROUND AND AIM OF WORK: Scintigraphy using a long lived radiolabelled somatostatin analogue [111In-DTPA-D-Phe1]-octreotide (OctreoScan) has previously been shown to be useful in the detection and management of neuroendocrine tumours, as well as in the imaging of various other malignant tumours. It was recently reported that the radiopharmaceutical accumulates also in the granulomatous lesions in Wegener's disease and in sarcoidosis. The present study was undertaken in order to evaluate the usefulness of the technique in detection of extrathoracic manifestations. METHODS: OctreoScan scintigraphy was performed in 5 patients with biopsy-proven sarcoidosis. A patient with a familial history of multiple endocrine neoplasia served as control. RESULTS: In 4/5 patients previously unknown granulomas were registered, and in the remaining subject the findings at the physical examination were confirmed. CONCLUSIONS: We conclude that somatostatin analogue scintigraphy may be helpful in finding extrathoracic granulomatous lesions in sarcoidosis, thus providing good prerequisites for focused biopsy attempts.

Adult↗
PubMed1996

[MIBI-scintigraphy. A simple and reliable method for localization of pathological parathyroid glands].

99Tcm-sestamibi scintigraphy was used to localise enlarged parathyroid glands in 25 patients with primary hyperparathyroidism previously operated in the neck, 20 of whom had recurrent disease and five had previously undergone surgery for thyroid disorders. Of the 18 patients for whom positive scans were obtained, nine were operated on the scan findings being confirmed. Crucial information was provided in two cases of intrathyroidal and one case of intramediastinal localisation of the pathological gland were not operated on as the hypercalcaemia was only marginal or the symptoms were vague. Though preoperative localisation of pathological parathyroid glands is a prerequisite for neck exploration in patients with persistent or recurrent hypercalcaemia due to primary (or secondary) hyperparathyroidism, the procedure is not cost-effective before the initial operation.

Adult↗
PubMed1996

Diagnosing sternal wound infections with 99mTc-labeled monoclonal granulocyte antibody scintigraphy.

BACKGROUND: Postoperative mediastinitis is a serious complication of thoracic operations. The diagnosis can sometimes be difficult, especially in cases with subacute clinical presentation. The aim of this study was to assess the clinical use of granulocyte scintigraphy and tomography in the diagnosis of postoperative wound infection and mediastinitis. METHODS: Twenty-nine patients after cardiothoracic operations were included, of whom 5 patients with a normal postoperative course formed the control group. We injected technetium 99m-monoclonal antigranulocyte antibodies and performed single-photon emission computed tomography after 4 and 20 hours. RESULTS: Twenty-three patients had both the early and the later scan; the remaining 6 had only the early scan. Seven scans indicated infection: 3 cases of mediastinitis, 2 cases of superficial wound infection, 1 case of infection in a synthetic aortic graft, and 1 case of osteitis. All were verified by bacterial culture. There was one false-negative scan; this patient had only the early registration and then was explored. CONCLUSIONS: This method when combined with the tomographic scan option is able to distinguish between deep and superficial infections. Two registrations must be made for optimal results.

Adult↗
PubMed1996

Rising incidence of pancreatic carcinoma in middle-aged and older women-time trends 1961-90 in the city of Malmö, Sweden.

The city of Malmö (population 230 000), situated in the south of Sweden, is in an area which has the highest incidence of pancreatic cancer in the country. The present study was designed to assess time trends of the incidence of pancreatic cancer 1961-90. The 1314 incident cases, 651 men and 663 women, were retrieved from the Regional Tumour Register and the National Cause-of-Death Register. In 75% of cases diagnosis was based on autopsy. Twenty per cent of the these cases were first found at autopsy, being undiagnosed. The average age-standardised incidence was 20.4 per 10(5) person-years for men and 13.7 for women. The incidence was higher for men than for women in all age groups above 44 years. No change in incidence over time was observed for men. In older and middle-aged women there was however a statistically significant increase. The average relative change in women above age 64 was 1.7% per year after age adjustment and in women aged 55-64 years 2.6% per year. We have found no results indicating that this increasing incidence could be caused by detection bias as a result of changing autopsy rates during the study period and hence conclude that the observed increase is explained by a growing number of women being exposed to factors with a potential tumour-promoting or -initiating effect.

Adult↗
PubMed1996

MR imaging, CT and CEA scintigraphy in the diagnosis of local recurrence of rectal carcinoma.

PURPOSE: To compare advanced imaging techniques in the diagnosis of recurrent rectal cancer. MATERIAL AND METHODS: Twenty-five consecutive patients with either suspected or verified recurrence were examined by CT (n = 25), MR with phased-array capabilities (n = 24) and CEA scintigraphy (n = 16). Three experienced radiologists (who were blinded to results obtained at surgery and histopathology) independently evaluated the films, one observer for each modality. RESULTS: The MR radiologist arrived at a correct diagnosis in 87.5% of the examinations, the CT radiologist in 76% and the CEA radiologist in 75%. The MR radiologist's results correlated more often with reported pathology than did those of the CT radiologist with regard to the relation of recurrent tumor to surrounding structures in the pelvis. CONCLUSION: MR imaging is the most effective of the 3 modalities in the diagnosis of recurrent rectal cancer.

Aged↗
PubMed1996

Collimator design for improved spatial resolution in SPECT and planar scintigraphy.

UNLABELLED: This paper evaluates the design of a new planar-concave collimator with nonuniform response that better matches the body shape than conventional collimators. METHODS: The collimator properties are evaluated and assessed by means of both a stimulation program and an experimental test using a prototype planar-concave collimator. RESULTS: The results, for points located 150 mm from the axis of rotation, demonstrate that the ratio of radial and tangential spatial resolution in SPECT with the new collimator decreased by 40%, as compared to SPECT with a standard collimator. In planar scintigraphy, the spatial resolution improved correspondingly from 10.9 mm (FWHM) to 7.8 mm in lateral areas of the body. CONCLUSION: The new collimator reduces nonisotropic blurring in SPECT in addition to improving spatial resolution in both planar scintigraphy and in SPECT.

Aged↗
PubMed1995

A 3-D method for delineation of activity distributions and assessment of functional organ volumes with SPECT.

The distribution volume of an organ may have a clinical impact in many cases and various methods have been designed to make volume assessments. In this paper, we describe a new method for delineation of the distribution outline and volume determination. The method is based on smoothing, differentiation, image relaxation and voxel counting of single photon emission computer tomography (SPECT) image sets with 3-D operators. A special routine corrects for the inherent thickness of the voxel-based outline. Phantom experiments, using a SPECT system with LEGP-collimator and a 64 x 64 acquisition matrix with 6.3 x 6.3 mm2 pixel size, demonstrated good correlation between the measured and the true volumes. For volumes larger than 120 cc the correlation coefficient was 0.9999 with SE 1.0 cc and an average relative deviation of 0.49%. For volumes below 120 cc, the accuracy was impaired due to low resolution power. By improving the system spatial resolution with an LEHR-collimator and a smaller pixel-size (4.1 x 4.1 mm2), good accuracy was achieved also for volumes in the range from 3 to 120 cc. Measurements of 15 differently shaped phantoms of volumes between 3 and 104 cc demonstrated high correlation between measured and true volumes: R = 0.9921 and SE = 0.74 cc (5.3%). For volumes as small as 3 and 5 cc, the difference between the true and the assessed volume was 0.6 cc. The reproducibility of the method was within 3% for volumes above 120 cc and within 7% for volumes below.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗