Dose coefficients of percentile-specific computational phantoms for photon external exposures

The use of dose coefficients (DCs) based on the reference phantoms recommended by the International Commission on Radiological Protection (ICRP) with a fixed body size may produce errors to the estimated organ/tissue doses to be used, for example, for epidemiologic studies depending on the body size of cohort members. A set of percentile-specific computational phantoms that represent 10th, 50th, and 90th percentile standing heights and body masses in adult male and female Caucasian populations were recently developed by modifying the mesh-type ICRP reference computational phantoms (MRCPs). In the present study, these percentile-specific phantoms were used to calculate a comprehensive dataset of body-size-dependent DCs for photon external exposures by performing Monte Carlo dose calculations with the Geant4 code. The dataset includes the DCs of absorbed doses for 29 individual organs/tissues from 0.01 to 104 MeV photon energy, in the antero-posterior, postero-anterior, right lateral, left lateral, rotational, and isotropic geometries. The body-size-dependent DCs were compared with the DCs of the MRCPs in the reference body size, showing that the DCs of the MRCPs are generally similar to those of the 50th percentile standing height and body mass phantoms over the entire photon energy region except for low energies (≤ 0.03 MeV); the differences are mostly less than 10%. In contrast, there are significant differences in the DCs between the MRCPs and the 10th and 90th percentile standing height and body mass phantoms (i.e., H10M10 and H90M90). At energies of less than about 10 MeV, the MRCPs tended to under- and over-estimate the organ/tissue doses of the H10M10 and H90M90 phantoms, respectively. This tendency was revised at higher energies. The DCs of the percentile-specific phantoms were also compared with the previously published values of another phantom sets with similar body sizes, showing significant differences particularly at energies below about 0.1 MeV, which is mainly due to the different locations and depths of organs/tissues between the different phantom libraries. The DCs established in the present study should be useful to improve the dosimetric accuracy in the reconstructions of organ/tissue doses for individuals in risk assessment for epidemiologic investigations taking body sizes into account.     

Trial of thyroid autotransplantation in patients with Graves' disease whose remnant thyroid has unintentionally been made too small at subtotal thyroidectomy

Autotransplantation of thyroid tissue was carried out in 5 patients with Graves' disease in order to prevent postoperative hypothyroidism, because the amount of remnant thyroid tissue was estimated to be too small, i.e. from 3 to 5 g. Approximately 0.5 to 2 g of thyroid tissue was cut into small pieces and transplanted into the sternocleidomastoid muscles or the strap muscles. Although the postoperative serum TSH levels were normal or slightly elevated, the serum concentrations of triiodothyronine were within the normal range in these 5 patients at a follow-up study carried out 2 to 7 years after surgery. Thyroid scanning with I-123 or 99mTc-pertechnetate (Tc-99m) revealed radioisotope uptake at the sites of transplantation in 4 of the 5 patients. These findings verify that the implanted thyroid tissues were alive and functioning and that autotransplantation may be a way of preventing postoperative hypothyroidism in patients whose remnant thyroid tissue has unintentionally become too small.     

Percutaneous ethanol injections in the treatment of nodular thyroid disease--fourteen years of experience

Surgery, radioactive iodine, and suppressive doses of Lthyroxine are commonly used in the treatment of benign nodular thyroid disease, with the best results achieved with surgery. However, recent advances in cytological diagnostic methods enable patients to choose alternative therapies if there are some contraindications or there is no agreement for surgery. Over past 14 years percutaneous ethanol injections (PEI), used in the past as a therapy for liver, kidney, parathyroid and adrenal cortical tumors, have been developed as an alternative method in the management of thyroid nodules. This paper reviews the investigations of a number aspects of PEI in the treatment of thyroid nodules reported in the literature. The evidence demonstrate that PEI is effective in the case of both solid non-toxic and autonomously functioning toxic nodules as well as cystic nodules. In majority of cases restore normal serum fT4, fT3 and TSH concentrations and shrink the tumor volume. The method seems to be safe and generally well tolerated by the patients. However, the current research base on the efficacy and PEI-associated risks is still inadequate to determine definitively its role as a standard treatment of benign nodular thyroid disease. For example, there is no detailed data comparing the results of treatment with PEI to standard treatment with radioactive iodine and L-thyroxine. Despite it, we conclude that PEI is a valuable method that earned recognition among other methods of the thyroid nodules treatment.     

Scintigraphic imaging of paediatric thyroid dysfunction

Imaging of thyroid dysfunction is safe and clinically relevant in children. In congenital hypothyroidism (CH), thyroid imaging permits a precise characterization of the aetiology, which is important for genetic counselling and clinical management. CH may be due to thyroid dysgenesis (ectopia, hypoplasia and athyrosis) or occurs in eutopic glands. In the latter, hypothyroidism may be either transient, especially after iodine overload, or due to permanent autosomal recessive dyshormonogenesis. Thyroid scintigraphy (TS) with either 99mTcO4 or 123I will identify ectopic thyroid tissue, which is the commonest cause of CH. However, recent reports favour the use of 123I, which enhances the accuracy of the aetiological classification. In cases of eutopic thyroid, the measurement of 123I uptake before and after perchlorate administration evaluates the organification process. At all ages, colour Doppler ultrasound scanning (CDU) is helpful in assessing thyroid volume, in identifying nodules and in characterizing tissue vascularization. TS and CDU images of most paediatric thyroid dysfunctions are presented.     

Method of complex morphofunctional study of the capillary bed of the thyroid gland]

The method is based on the cytospectrophotometric estimation of the histochemical reaction to alkaline phosphatase in the gland capillary and on determination of the relative volume occupied by the functioning capillaries. A model experiment under conditions of hyperplasia and hypoplasia of the organ has shown considerable differences in the gland blood supply. Under these conditions the changes of the functioning capillary bed were more pronounced than those of the organ mass.     

Analysis of a novel offset cone-beam computed mammotomography system geometry for accomodating various breast sizes

We evaluate a newly developed dedicated cone-beam transmission computed mammotomography (CmT) system configuration using an optimized quasi-monochromatic cone beam technique for attenuation correction of SPECT in a planned dual-modality emission and transmission system for pendant, uncompressed breasts. In this study, we perform initial CmT acquisitions using various sized breast phantoms to evaluate an offset cone-beam geometry. This offset geometry provides conjugate projections through a full 360 degree gantry rotation, and thus yields a greatly increased effective field of view, allowing a much wider range of breast sizes to be imaged without truncation in reconstructed images. Using a tungsten X-ray tube and digital flat-panel X-ray detector in a compact geometry, we obtained initial CmT scans without shift and with the offset geometry, using geometrical frequency/resolution phantoms and two different sizes of breast phantoms. Acquired data were reconstructed using an ordered subsets transmission iterative algorithm. Projection images indicate that the larger, 20 cm wide, breast requires use of a half-cone-beam offset scan to eliminate truncation artifacts. Reconstructed image results illustrate elimination of truncation artifacts, and that the novel quasi-monochromatic beam yields reduced beam hardening. The offset geometry CmT system can indeed potentially be used for structural imaging and accurate attenuation correction for the functional dedicated breast SPECT system.     

The estimation of the goiter by means of ultrasonography and scintigraphy (SPECT) with using 131I

INTRODUCTION: Ultrasonography (US) and scintigraphy (SPECT) are used to evaluate the volume of thyroid glands. An accurate estimation of the thyroid volume, among other factors, is necessary to calculate the suitable radioactive iodine dose, which determines the success of the therapy. The aim of the study was to estimate the volume of the goiter by means of US and (131)I-SPECT. MATERIAL AND METHODS: A group of 80 patients with a thyroid disorder in their past medical history was examined. Patients were divided into two groups. The group A contained 50 patients (39 females, 11 males) with a goiter, where the volume of the thyroid was evaluated with the use of US and (131)I-SPECT. The group B contained 30 patients (21 females, 9 males) with a normal volume of the thyroid gland shown by US and (131)I-SPECT. US of the thyroid gland was made by means of an ALOKA SSD 500 device, with the linear head 7.5 MHz frequency. (131)I-SPECT was made by means of a one head gammacamera Diacam with a high energy collimator. RESULTS: In the group A, the average volume of the goiter was 44.55 ml in US and 49.67 ml in SPECT (p<0.001). In control group B the average volumes of the thyroid gland were respectively 13.83 ml vs. 16.19 ml (p<0.001). CONCLUSION: The results of the thyroid volume measurement was dependent on the method used in both the investigated and control groups.     

“Omnidia”: software for taxonomy,calculation of diatom indices and inventories management

Software for calculation of 6 diatom indices and diversity indices has been created for both Macintosh and IBM compatible computers. This software runs with the data base Omnis 5 under Windows 3.0. It includes three taxonomic files: families, genera and species, and an inventories file. Four types of data inputs are possible. It is always possible to operate simulations and to carry out investigations with simple or combined characters. All files and results of investigations can be listed in different ways. This data base is compatible with both word processing and spreadsheet systems.     

Comparison of three histometric methods for the comprehension of stimulating effects on the rat thyroid gland

There exist some histometric methods for the morphological quantification of different strongly stimulating effects on the thyroid gland induced by drugs and/or other chemical substances in dependence upon dose and duration of application. But in respect of technical and temporal expense and also diagnostic statement, there are considerable differences between these recording procedures. Therefore we examined the 3 mostly used methods synchronously (i.e. determination of thyroid epithelial cell height, nuclear volume in thyrocytes, and estimation of relative volume parts in the thyroid gland by the point counting method) by investigating the thyroid glands of methylthiouracil-(MTU)-stimulated rats and corresponding controls in order to compare the diagnostic value and temporal expense. The largest temporal expense was required in the nuclear volume determination, the smallest in the point-counting method. On principle, all 3 procedures allow the determination of hypertrophic alterations but only by help of the point-counting method, also hyperplastic changes are recognizable. By nuclear volume determination, we found significant differences between central and peripheral parts of the thyroid gland. Therefore, to avoid the subjective error, it will be necessary to measure a large number of nuclei in many planes of the gland. Also the determination of epithelial cell high reinforces the subjective error because of the heterological structure especially in unstimulated thyroid gland. If the number of counting points is exactly determined and, full of sense, limited, the point-counting method allows a nearly complete measuring of the whole object to be tested within an acceptable investigation time. In this way, the heterological structure of thyroid gland will be regarded, and comparability and reproducibility are guaranteed on an high level.     

CT-Based Attenuation Correction in I-123-Ioflupane SPECT

Purpose

Attenuation correction (AC) based on low-dose computed tomography (CT) could be more accurate in brain single-photon emission computed tomography (SPECT) than the widely used Chang method, and, therefore, has the potential to improve both semi-quantitative analysis and visual image interpretation. The present study evaluated CT-based AC for dopamine transporter SPECT with I-123-ioflupane.

Materials and methods

Sixty-two consecutive patients in whom I-123-ioflupane SPECT including low-dose CT had been performed were recruited retrospectively at 3 centres. For each patient, 3 different SPECT images were reconstructed: without AC, with Chang AC and with CT-based AC. Distribution volume ratio (DVR) images were obtained by scaling voxel intensities using the whole brain without striata as reference. For assessing the impact of AC on semi-quantitative analysis, specific-to-background ratios (SBR) in caudate and putamen were obtained by fully automated SPM8-based region of interest (ROI) analysis and tested for their diagnostic power using receiver-operator-characteristic (ROC) analysis. For assessing the impact of AC on visual image reading, screenshots of stereotactically normalized DVR images presented in randomized order were interpreted independently by two raters at each centre.

Results

CT-based AC resulted in intermediate SBRs about half way between no AC and Chang. Maximum area under the ROC curve was achieved by the putamen SBR, with negligible impact of AC (0.924, 0.935 and 0.938 for no, CT-based and Chang AC). Diagnostic accuracy of visual interpretation also did not depend on AC.

Conclusions

The impact of CT-based versus Chang AC on the interpretation of I-123-ioflupane SPECT is negligible. Therefore, CT-based AC cannot be recommended for routine use in clinical patient care, not least because of the additional radiation exposure.     

The relation between the specific absorption rate and electromagnetic field intensity for heterogeneous exposure conditions at mobile communications frequencies

The relation between the incident electromagnetic field strength and both the whole‐body and the local specific absorption rate (SAR) was investigated for typical heterogeneous exposure scenarios for frequencies relevant for mobile communication. The results were compared to results from plane wave exposure. Heterogeneous exposure arises from multiple path propagation of the electromagnetic waves to the location of interest. It is shown that plane wave exposure does not represent worst‐case exposure conditions. When the electric field strength arising at plane wave exposure is compared to the electric field strength averaged over the volume of the human body occurring during multipath exposure, 12% of all heterogeneous cases examined represent worse exposure conditions than plane wave exposure for whole‐body exposure at 946 MHz, 15% at 1840 MHz, and 22% at 2140 MHz. The deviation between plane wave and heterogeneous whole‐body SAR ranges from ?54% to 54%. For partial‐body SAR averaged over 10 g of tissue, a range from ?93% to 209% was found when comparing multiple wave exposure to single incoming plane waves. The investigations performed using the Visible Human as phantom showed that the basic restrictions are met as long as the reference levels are not exceeded. However, this must not be necessarily the case when different phantoms are used to perform similar investigations because recent studies demonstrated that reference levels might not be conservative when phantoms of children are used. Therefore, the results of this work indicate the need to extend the investigations to numerical simulations with additional human phantoms representing parts of the human population having different anatomy and morphology compared to the phantom used within the frame of this project. This also applies to phantoms of children. Bioelectromagnetics 30:651–662, 2009. © 2009 Wiley‐Liss, Inc.     

Organ scaling in the raccoon dog Nyctereutes procyonoides gray 1834, as monitored by influences of internal and external factors

1. Animals fed a high energy ration had bigger body weight, and bigger heart, brain and genitals then animals fed a normal diet, but they had substantially smaller liver, kidneys, adrenals and thyroid glands than the otherwise smaller animals. Restricted feeding did not necessarily produce smaller organ sizes than normal. 2. The yearly variation in organ sizes was astonishingly large whereas the sex differences were rather rare. 3. For organs like liver, kidneys and thyroid glands the conclusion from the results was independent of the method of expressing the organ mass. The organ sizes seemed to be influenced by many coexisting factors like yearly differences, sex and age of animals, feed and farm.     

Reference values of thyroid volume in a healthy, non-iodine-deficient Spanish population.

Our aim was to assess reference values of thyroid volume by ultrasonography in healthy adult subjects. We conducted an epidemiological cross-sectional study where 880 subjects were randomly selected from the town census of L'Hospitalet de Llobregat after being invited to participate in our study directly by mail and phone call. We made a clinical history of each subject and determined serum thyrotropin, antiperoxidase antibodies, urinary iodine excretion and thyroid volume by ultrasonography. Subjects with thyroid disease were excluded. We finally studied 268 representative subjects. The reference thyroid volume was median 7.31 ml, mean 8.22 ml (Confidence Interval: 7.75 - 8.69 ml). In men: median 9.19 ml, mean 9.87 ml (CI: 9.09 - 10.65 ml); in women: median 6.19 ml, mean 6.57 ml (CI: 6.22 - 9.92 ml) (p < 0.0001). We grouped the subjects into decades, and found that thyroid volume was different (p = 0.0034) in males because the younger group had lower volume. We did not find any differences among age groups in women. The mean of the urinary iodine excretion was 154.23 microg/l. We have determined reference values of thyroid volume measured by ultrasonography in our iodine non-deficient population and prepared tables that distribute thyroid volume by sex and age.     

Quantitative comparison between the commercial software STRATOS® by Philips and a homemade software for voxel-dosimetry in radiopeptide therapy

BackgroundTargeted radionuclide therapy is a rapidly growing modality. A few commercial treatment planning systems are entering the market. However, some in-house systems are currently developed for a more flexible and customized dosimetry calculation at voxel-level. For this purpose, we developed a novel software, VoxelMed, and performed a comparison with the software STRATOS.MethodsThe validation of both of them was undertaken using radioactive phantoms with different volume inserts. A cohort of 10 patients was also studied after a therapeutic administration of ¹⁷⁷Lu-labelled radiopeptides. The activity, number of disintegrations, absorbed dose and dose-volume histogram (DVH) were calculated for the phantoms and the kidneys in patients, which were the main critical organs at risk in this study.ResultsIn phantoms the absorbed doses computed with VoxelMed and STRATOS agree within 5%. In patients at the voxel-level the absorbed dose to kidneys (VoxelMed: mean 0.66 Gy/GBq) showed a limited difference of 5%, but with a remarkable range (−40%, +60%) between the two software packages. Voxel-dosimetry allows to estimate the dose non-homogeneities in volumes, which may be evaluated through DVHs.ConclusionThis study demonstrates that a fully 3D voxel-dosimetry with multiple SPECT images is feasible by using home-made or commercial software package and absorbed dose results obtained are similar. The main difference between the studied tools was observed in the activity integration method (effective vs physical half-time to time activity curve tail). We believe that an effective half-time integration method produces a more accurate approximation of clinical uptake and resultant dosimetry.     

On the Utility of MIBG SPECT/CT in Evaluating Cardiac Sympathetic Dysfunction in Lewy Body Diseases

BackgroundAbnormal cardiac uptake of ¹²³I-metaiodobenzylguanidine (¹²³I-MIBG) is a diagnostic marker of Lewy body diseases (LBDs), e.g., Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). Planar imaging is generally used to assess cardiac sympathetic dysfunction in ¹²³I-MIBG scintigraphy; however, its clinical utility requires further improvement. We hypothesized that the co-registration of single-photon emission tomography (SPECT) and computed tomography (CT) images would improve the diagnostic accuracy of ¹²³I-MIBG cardiac scintigraphy for LBDs. This study sought to evaluate the effects of SPECT/CT imaging on ¹²³I-MIBG cardiac scintigraphy for diagnosing LBDs.MethodsWe retrospectively investigated data of 54 patients (consecutive 18 patients in each PD, DLB, and idiopathic normal pressure hydrocephalus [iNPH] groups) who underwent ¹²³I-MIBG cardiac scintigraphy (planar and SPECT/CT) because of suspected LBDs at the Tohoku University hospital from June 2012 to June 2015. We compared the diagnostic accuracies of the conventional planar ¹²³I-MIBG method and SPECT/CT methods (manual and semi-automatic).ResultsIn the conventional planar analysis, ¹²³I-MIBG uptake decreased only in the DLB group compared with the iNPH group. In contrast, the SPECT/CT analysis revealed significantly lower ¹²³I-MIBG uptake in both the PD and DLB groups compared with the iNPH group. Furthermore, a receiver operating characteristic analysis revealed that both the manual and semi-automatic SPECT/CT methods were superior to the conventional planar method in differentiating the 3 disorders.ConclusionsSPECT/CT ¹²³I-MIBG cardiac scintigraphy can detect mild cardiac sympathetic dysfunction in LDBs. Our results suggest that the SPECT/CT technique improves diagnostic accuracy for LBDs.     

An improved assay method for thyroid peroxidase applicable for a few milligrams of abnormal human thyroid tissues

A peroxidase assay method (Mini assay method) which is applicable for a minute amount (as small as a few mg) of thyroid tissue was developed, employing guaiacol or iodide as the second substrate. This method is a modification of the previous one (Ordinary assay method): the volume of the reaction mixture was reduced to about one-tenth with prior solubilization of the enzyme. The correlation between the Mini assay and Ordinary assay methods, and between the guaiacol and iodide assays by both methods were satisfactorily good, but the iodine content of thyroglobulin was found to be not directly correlated to the peroxidase activities. Protein-based specific activities of peroxidase from normal human thyroid tissue were about 0.030 guaiacol units/mg protein and 0.0066 iodide units/mg protein, which were slightly higher than those of porcine thyroid tissue. The Mini assay method developed in the present study was used for the determination of peroxidase activity in a small amount (1-8 mg) of thyroid tissue obtained by means of a needle biopsy from patients with thyroid disorders. One specimen (goitrous cretinism) showed no peroxidase activity in both the guaiacol and iodide assays, and three specimens (two chronic thyroiditis, one familial nontoxic goiter) possessed no ability to catalyze the oxidation of iodide in spite of the high reactivity towards guaiacol, suggesting the presence of an abnormal peroxidase in these tissues.     

Location of radiosensitive organs inside pediatric anthropomorphic phantoms: Data required for dosimetry

PurposeThe aim of this study was to determine the location of radiosensitive organs in the interior of four pediatric anthropomorphic phantoms for dosimetric purposes.MethodsFour pediatric anthropomorphic phantoms representing the average individual as newborn, 1-year-old, 5-year-old and 10-year-old child underwent head, thorax and abdomen CT scans. CT and MRI scans of all children aged 0–16 years performed during a 5-year-period in our hospital were reviewed, and 503 were found to be eligible for normal anatomy. Anterior-posterior and lateral dimensions of twelve of the above children closely matched that of the phantoms' head, thoracic and abdominal region in each four phantoms. The mid-sagittal and mid–coronal planes were drawn on selected matching axial images of patients and phantoms. Multiple points outlining large radiosensitive organs in patient images were identified at each slice level and their orthogonal distances from the mid-sagittal and mid–coronal planes were measured. In small organs, the coordinates of organs' centers were similarly determined. The outlines and centers of all radiosensitive organs were reproduced using the coordinates of each organ on corresponding phantoms’ transverse images.ResultsThe locations of the following radiosensitive organs in the interior of the four phantoms was determined: brain, eye lenses, salivary glands, thyroid, lungs, heart, thymus, esophagus, breasts, adrenals, liver, spleen, kidneys, stomach, gallbladder, small bowel, pancreas, colon, ovaries, bladder, prostate, uterus and rectum.ConclusionsThe production of charts of radiosensitive organs inside pediatric anthropomorphic phantoms was feasible and may provide users reliable data for positioning of dosimeters during direct organ dose measurements.     

Commissioning and validation of commercial deformable image registration software for adaptive contouring

PurposeTo report the commissioning and validation of deformable image registration(DIR) software for adaptive contouring.MethodsDIR (SmartAdapt®v13.6) was validated using two methods namely contour propagation accuracy and landmark tracking, using physical phantoms and clinical images of various disease sites. Five in-house made phantoms with various known deformations and a set of 10 virtual phantoms were used. Displacement in lateral, anterio-posterior (AP) and superior-inferior (SI) direction were evaluated for various organs and compared with the ground truth. Four clinical sites namely, brain (n = 5), HN (n = 9), cervix (n = 18) and prostate (n = 23) were used. Organs were manually delineated by a radiation oncologist, compared with the deformable image registration (DIR) generated contours. 3D slicer v4.5.0.1 was used to analyze Dice Similarity Co-efficient (DSC), shift in centre of mass (COM) and Hausdorff distances Hf_95%/avg.ResultsMean (SD) DSC, Hf_95% (mm), Hf_avg (mm) and COM of all the phantoms 1–5 were 0.84 (0.2) mm, 5.1 (7.4) mm, 1.6 (2.2) mm, and 1.6 (0.2) mm respectively. Phantom-5 had the largest deformation as compared to phantoms 1–4, and hence had suboptimal indices. The virtual phantom resulted in consistent results for all the ROIs investigated. Contours propagated for brain patients were better with a high DSC score (0.91 (0.04)) as compared to other sites (HN: 0.84, prostate: 0.81 and cervix 0.77). A similar trend was seen in other indices too. The accuracy of propagated contours is limited for complex deformations that include large volume and shape change of bladder and rectum respectively. Visual validation of the propagated contours is recommended for clinical implementation.ConclusionThe DIR algorithm was commissioned and validated for adaptive contouring.     

Localization of transferrin receptors (TFRs) in human non functioning thyroid nodules and in extranodular thyroid tissue

In this research the TFR localization in non functioning human thyroid nodules and in the extranodular thyroid tissue, using an immunohistochemical technique, has been studied. For this study a monoclonal antibody (B3/25) against TFR and the peroxidase technique have been utilized. Moreover a morphometric comparative analysis was carried out based on the following parameters: 1) mean immunoreactive area for microscopic field, 2) mean value of immunoreactive follicular perimeter, 3) integrated optical density, 4) % of immunoreactive area on total examined area in nodular and extranodular tissue. The immunoreactivity was detected in some follicular cells in a number of follicles randomly distributed in the extra nodular tissue. As concern the non functioning thyroid nodules, the positivity was localized in the generality of the follicles both in the flattened epithelial cells of the larger follicles and in the cuboidal cells of the smaller ones. The morphometric parameters confirm a statistically significant difference of immunoreactivity between extranodular and nodular tissue. These results suggest that TF might play a role in the cellular proliferation of thyroid gland.     

Quantitative histological studies of mast cells in the thyroid of sand rats (Psammomys obesus) during the development of a mellitus syndrome

Mast cells in the thyroid glands of sand rats with different disturbances of the carbon hydrate tolerance (reference-, impaired-glucose-tolerance-, and diabetic group) are quantitative-histologically investigated. In the IGT-group (impaired glucose tolerance), mast cells are significant increased. However, the number of these cells in the diabetic group decreased significantly. This investigations demonstrate that the mellitus-syndrome is not only a complex neuroendocrine but also a disturbance of biogenic amines and the organ of the connective tissue.