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Diffusion characteristics in bentonite are essential to quantify the transport of radionuclides through buffer/backfill materials in waste repositories. This study employs through-diffusion techniques to investigate the diffusion behavior of 99TcO4− through SPV bentonite with various densities. The apparent diffusion coefficients for bentonite densities are estimated using Marquardt–Levenberg optimization algorithm in the HYDRUS-1D model. Based on the experimental and calculation results, 99Tc could be considered as non-sorbing radionuclides. The data obtained in this study provide a valuable reference for the safety assessment of waste repositories.

To test the diagnostic performance of bone SPECT/CT and MRI for the evaluation of bone viability in patients after girdlestone-arthroplasty with histopathology used as gold standard. In this cross-sectional study, patients after girdlestone-arthroplasty were imaged with single-photon-emission-computed-tomography/computed-tomography (SPECT/CT) bone-scans using 99mTc-DPD. Additionally, 1.5 T MRI was performed with turbo-inversion-recovery-magnitude (TIRM), contrast-enhanced T1-fat sat (FS) and T1-mapping. All imaging was performed within 24 h prior to revision total-hip-arthroplasty in patients with a girdlestone-arthroplasty. In each patient, four standardized bone-tissue-biopsies (14 patients) were taken intraoperatively at the remaining acetabulum superior/inferior and trochanter major/minor. Histopathological evaluation of bone samples regarding bone viability was used as gold standard. A total of 56 bone-segments were analysed and classified as vital (n = 39) or nonvital (n = 17) by histopathology. Mineral/late-phase SPECT/CT showed a high sensitivity (90%) and specificity (94%) to distinguish viable and nonviable bone tissue. TIRM (sensitivity 87%, specificity 88%) and contrast-enhanced T1-FS (sensitivity 90%, specificity 88%) also achieved a high sensitivity and specificity. T1-mapping achieved the lowest values (sensitivity 82%, specificity 82%). False positive results in SPECT/CT and MRI resulted from small bone fragments close to metal artefacts. Both bone SPECT/CT and MRI allow a reliable differentiation between viable and nonviable bone tissue in patients after girdlestone arthroplasty. The findings of this study could also be relevant for the evaluation of bone viability in the context of avascular bone necrosis.

In patients with early stage gastric cancer in the middle third of the stomach, pylorus-preserving gastrectomy (PPG) can be an option as function-preserving surgery, although its oncologic safety is not definitively defined. This issues may be overcome using the sentinel node (SN) concept. The aim of this study was to investigate the effectiveness of the SN concept in early gastric cancer patients who are candidates for PPG. One hundred fifty-six patients with middle-third location of cT1N0 gastric cancer (single lesion

Sentinel node (SN) mapping in esophageal cancer has been reported to be technically feasible with an acceptable detection rate and accuracy. However, the clinical significance and survival analysis findings associated with the metastatic status of SNs in patients with early-stage esophageal cancer have not been clarified. In this study, we investigated the clinical significance and survival impact of SN mapping in early-stage esophageal cancer. Among patients who were diagnosed preoperatively with clinical T1N0M0 or T2N0M0 esophageal cancer and who underwent SN mapping, 70 consecutive patients who were diagnosed with pathological T1 primary thoracic esophageal cancer were enrolled in this study. Sixty-four (91 %) patients were diagnosed with squamous cell carcinoma while 5 (7 %) patients were with adenocarcinoma. Endoscopic injection of technetium-99m tin colloid was performed before surgery, and radioactive SNs were identified by preoperative lymphoscintigraphy and intraoperative gamma probing. Standard esophagectomy with lymphadenectomy was performed in all patients, and all resected nodes were evaluated by routine pathological examination. SNs were successfully detected in 65 (92.9 %) of 70 patients with pT1 esophageal cancer. The sensitivity to predict lymph node metastasis was 91.7 %, and the diagnostic accuracy based on SN status was 96.9 %. Although there was a wide distribution of SNs from cervical to abdominal areas, 84.5 % of the patients had no lymph node metastasis or had lymph node metastasis only in SN. The disease-specific survival of the patients with metastatic non-SNs was significantly worse relative to that of the patients with no lymph node metastasis or lymph node metastasis only in SN. This study demonstrated that radio-guided SN mapping is useful not only as an accurate diagnostic tool for detecting lymph node metastasis but also as a tool for prognostic stratification in patients with cN0 early esophageal cancer.

Background Dementia with Lewy bodies (DLB) is the second most frequent diagnosis of progressive degenerative dementia in older people. Delusions are common features in DLB and, among them, Capgras syndrome represents the most frequent disturbance, characterized by the recurrent and transient belief that a familiar person, often a close family member or caregiver, has been replaced by an identical-looking imposter. However, other delusional conditions near to misidentification syndromes can occur in DLB patients and may represent a major psychiatric disorder, although rarely studied systematically. Case presentation We reported on a female patient affected by DLB who presented with an unusual delusion of duplication. Referring to the female professional caregiver engaged by her relatives for her care, the patient constantly described the presence of two different female persons, with a disorder framed in the context of a delusion of duplication. A brain 99Tc-hexamethylpropyleneamineoxime SPECT was performed showing moderate hypoperfusion in both occipital lobes, and associated with marked decreased perfusion in parieto-fronto-temporal lobes bilaterally. Conclusions An occipital hypoperfusion was identified, although in association with a marked global decrease of perfusion in the remaining lobes. The role of posterior lobes is certainly important in all misidentification syndromes where a natural dissociation between recognition and identification is present. Moreover, the concomitant presence of severe attentional and executive deficits evocative for a frontal syndrome and the marked global decrease of perfusion in the remaining lobes at the SPECT scan also suggest a possible dysfunction in an abnormal connectivity between anterior and posterior areas. Electronic supplementary material The online version of this article (doi:10.1186/s12883-017-0842-1) contains supplementary material, which is available to authorized users.

(32)P-chromic phosphate colloid treatments of astrocytoma and craniopharyngioma cystic brain tumours in paediatric patients are conventionally based on a sphere model under the assumption of uniform uptake. The aims of this study were to determine the distribution of the absorbed dose delivered by (32)P on a patient-specific basis and to evaluate the accuracy with which this can be predicted from a pretherapy administration of (99m)Tc-Sn colloid.Three patients were treated with (32)P-chromic phosphate colloid following (99m)Tc-Sn colloid administrations. Convolution dosimetry was performed using pretherapy and posttherapy sequential SPECT imaging, and verified with EGSnrc Monte Carlo radiation transport simulations. Mean absorbed doses to the cyst wall and dose-volume histograms were also calculated and compared with those obtained by the sphere model approach.Highly nonuniform uptake distributions of both the (99m)Tc and (32)P colloids were observed and characterized by dose-volume histograms to the cyst wall. Mean absorbed doses delivered to the cyst wall, obtained with the convolution method, were on average 21 % (SD 18 %) and 50 % (SD 30 %) lower than those predicted by the (99m)Tc distribution and the uniform assumption of the sphere model, respectively.Absorbed doses delivered to the cyst wall by (32)P are more accurately predicted from image-based patient-specific convolution dosimetry than from simple sphere models. These results indicate the necessity to perform personalized treatment planning and verification for intracavitary irradiation of cystic brain tumours treated with radiocolloids. Patient-specific dosimetry can be used to guide the frequency and levels of repeated administrations and would facilitate data collection and comparison to support the multicentre trials necessary to progress this therapy.

Sentinel lymph node biopsy with lymphoscintigraphy has become the standard method for the detection of axillary lymph node metastasis in breast cancer patients. However, there is no standardized radiopharmaceutical. For the detection of axillary lymph node metastasis by lymphoscintigraphy and sentinel node biopsy in patients with breast cancer, we compared the results between subareolar injection of (99m)Tc-tin colloid and injection of (99m)Tc-phytate. This study included 516 breast cancer patients who underwent surgery between 2001 and 2010. Among the 516 patients, (99m)Tc-tin colloid (37-185 MBq) was administered to 412 patients by subareolar injection, and (99m)Tc-phytate (37-185 MBq) was injected in 104 patients. Lymphoscintigraphy was performed with the patients in the supine position, and sentinel node identification was performed by hand-held gamma probe during surgery. Among 412 patients with (99m)Tc-tin colloid, the sentinel node was identified by lymphoscintigraphy in 364 cases (88.3%) and by a gamma probe in 369 cases (89.6%). Among 104 patients with (99m)Tc-phytate, 101 cases (97.1%) were identified by lymphoscintigraphy and 101 cases (97.1%) were identified by a gamma probe. The identification rates by lymphoscintigraphy and gamma probe were superior with (99m)Tc-phytate, as compared with (99m)Tc-tin colloid, with a statistically significant difference (P < 0.05 for both methods). (99m)Tc-phytate is a better choice than (99m)Tc-tin colloid for identification of the sentinel node in breast cancer patients.

To reduce accumulation in the abdomen by MORF/cMORF pretargeting, 111In was compared to 99mTc as the radiolabel.After receiving either 99mTc (MAG3)-cMORF or 111In (DTPA)-cMORF, normal mice were imaged and killed for pharmacokinetics. Thereafter, tumored mice were pretargeted withMORF-antibody, 48 h later were given an injection of 99mTc- or 111In-cMORF, and finally were imaged repeatedly.The cMORF biodistribution in both normal and pretargeted tumored mice was influenced by its radiolabel. While excretion of both 99mTc-cMORF and 111In-cMORF was rapid and mainly through the kidneys, about 2% of 99mTc accumulated in the intestines compared toessentially no intestinal accumulation for 111In at any time. Tumor accumulation was unchanged.In applications of MORF/cMORF pretargeting intended to image organs deep within the abdomen such as the pancreas, radiolabeling with 111In may be superior to 99mTc.

In breast cancer, neoadjuvant chemotherapy (NAC) is widely used in order to enable a conservative surgery. In patients treated with NAC, the use of sentinel lymph node (SLN) biopsy, which is a good predictor of the axillary nodal status in previously untreated patients, is still discussed. The aim of our study was to determine clinicopathological factors that may influence the accuracy of SLN biopsy after NAC.Between March 2001 and December 2006, 129 patients with infiltrating breast carcinoma were studied prospectively. Preoperatively, all of them underwent NAC. At surgery, SLN biopsy followed by axillary lymph node (ALN) dissection was performed. Lymphatic mapping was done using the isotope method.The SLN identification rate was 93.8% (121/129). Fifty-six out of the 121 successfully mapped patients had positive ALN. Eight out of these 56 patients had tumor-free SLN (false-negative rate of 14.3%). The false-negative rate was correlated with larger tumor size (T1-T2 versus T3; P = 0.045) and positive clinical nodal status (N0 versus N1-N2; P = 0.003) before NAC. In particular, the false-negative rate was 0% (0/29) in N0 patients and 29.6% (8/27) in N1-N2 patients. Clinical and pathological responses to NAC did not influence the accuracy of SLN biopsy.Our results show that clinical nodal status is the main clinicopathological factor influencing the false-negative rate of SLN biopsy after NAC for breast cancer. SLN biopsy after NAC can predict the ALN status with a high accuracy in patients who are clinically lymph node negative at presentation.

In recent years, some surgeons have been warned of possible problems with sentinel lymph node diagnosis (SLND) for patients who have undergone transaxillary breast augmentation (TBA), although no scientific studies support this warning. The authors report two additional cases of breast cancer in which the SLND was successfully performed for patients with previous TBA. The surgical anatomy of the axilla, the groups of lymph nodes, and a personal way of performing TBA are described. Five other reports concerning the same issue are thoroughly discussed. Four of these are clinical in vivo reports, and one is a cadaver study. The four in vivo studies and what we are reporting now clearly demonstrate that what was said regarding possible problems in the SLND after TBA was not founded on clinical research and contradicts these five clinical findings.

Subdiaphragmatic activity and diaphragmatic motion both contribute to inferior wall artifacts in technetium 99m myocardial perfusion single photon emission computed tomography (SPECT).We used an anthropomorphic phantom with ventricular wall activity, liver/spleen inserts containing variable Tc-99m activity, and variable vertical (diaphragmatic) motion amplitude. SPECT and transmission scans were obtained on a GE Optima NX camera. Data were processed by use of filtered backprojection or attenuation correction (AC). Resulting myocardial activity maps were analyzed with standardized inferior-anterior and anterior-lateral wall ratios. At a subdiaphragmatic-myocardial activity ratio of 0.5:1, inferior wall attenuation predominates, producing a cold artifact. AC corrects inferior wall activity to the level of the anterior wall irrespective of diaphragmatic motion. At a subdiaphragmatic-myocardial activity ratio of 1:1, inferior wall counts vary widely depending on the proximity of subdiaphragmatic activity to the ventricle. With increasing diaphragmatic amplitude, the overlap of subdiaphragmatic activity and inferior wall worsens, leading to a complex mixture of cold and hot artifacts, not corrected by AC.Concentration and proximity of subdiaphragmatic Tc-99m activity relative to myocardium comprise a major factor in the nature and severity of inferior wall artifacts. If the subdiaphragmatic Tc-99m concentration is equivalent to that in the myocardium, complex, potentially uninterpretable hot and cold inferior wall artifacts are produced.

We report a case of intrathoracic extramedullary hematopoiesis associated with hemolytic anemia. While the paravertebral localization of the lesions demonstrated on CT and MRI was suspicious of intrathoracic extramedullary hematopoiesis, In-111 chloride and Tc-99m Sn colloid bone marrow scintigraphies showing a bone marrow element of the lesion were useful to confirm the diagnosis.

Hintergrund. Das “Lymphatic mapping” und das Sentinel-Lymphknotenkonzept sind beim malignen Melanom und beim Mammakarzinom bereits etabliert.Die Anwendung bei anderen soliden Tumoren ist Gegenstand derzeitiger Untersuchungen und wird kontrovers beurteilt. Als Erfolg versprechender Ansatz bietet sich das selektive Lymphknotenstaging bei Patienten mit einem Magenkarzinom an. Die vorliegende Pilotstudie untersucht die Durchfuhrbarkeit mittels Radiokolloidtechnik und die Genauigkeit bei der Bestimmung des Lymphknotenstatus. Patienten und Methode. Bei 15 Patienten mit einem Magenkarzinom (u T1–3) erfolgte 17 (±3) h praoperativ eine submukose endoskopische Umspritzung mit 0,4 ml 60 MBq m99Tc-Nanocis® um den Tumor. Unmittelbar nach der Laparotomie wurde die Aktivitat der 16 Lymphknotenstationen (JGCA) mit einer Hand-γ-Sonde gemessen. Alle Patienten wurden einer Gastrektomie mit D2-Lymphadenektomie unterzogen.Nach der Resektion wurde der Operationssitus nach verbliebener Aktivitat abgescannt. Alle Nuklid speichernden Lymphknoten mit einer 10fachen Aktivitat gegenuber dem Grundrauschen wurden als Sentinel-Lymphknoten (SLN) definiert und am Operationspraparat entfernt. Die SLN's wurden gesondert in Serienschnitten und mittels Immunhistochemie aufgearbeitet. Ergebnisse. Bei 14 von 15 Patienten konnte ein SLN detektiert werden (93%). Die mediane Zahl der SLN's betrug 3 (1–5).Von 14 untersuchten Patienten waren 9 nodal positiv. In 8 von diesen 9 Fallen konnte mit dem SLN der positive Lymphknotenstatus vorausgesagt werden,wobei in 5 Fallen die Lymphknotenstation mit dem befallenen SLN die einzige befallene Station war. Damit lag die Sensitivitat der Methode bei 89%.In einem Fall zeigte die immunhistochemische Untersuchung des SLN bei einem initial nodal negativen Patienten isolierte Tumorzellen im Randsinus (“Upstaging”). Zusammenfassung. Das “Lymphatic mapping” und die Sentinel-Lymphknotendiagnostik sind beim Magenkarzinom durchfuhrbar.Die ersten Ergebnisse deuten auf eine korrekte Bestimmung des Lymphknotenstatus mit dieser Methode hin.Durch die gezielte histologische Aufarbeitung der SLN's ist zusatzlich ein Upstaging moglich.Weitere zahlenmasig grosere Untersuchungen mussen sich anschliesen,um den klinischen Wert der Methode weiter zu klaren.

Contrary to common belief, organometallic compounds exhibit remarkable stability in aerobic and even diluted aqueous solutions. Technetium-sestamibi (Cardiolite) is one of the most prominent examples of this class of compounds routinely used in nuclear medicine. This review summarises the recent progress in labelling of biomolecules with organometallic complexes for diagnostic and therapeutic application in radiopharmacy and exemplifies in detail developments focussing on organometallic technetium- and rhenium-tricarbonyl technologies. The value of such technologies has been recognised and they have become a valuable alternative to common labelling methodologies. An increasing number of groups have started to employ an organometallic precursor for the purpose of radioactive labelling of various classes of biomolecules, and the advantages and limitations of this new technique are compared with those of other labelling methods. The synthetic access to appropriate precursors via double-ligand exchange or aqueous carbonyl kit preparation for routine application is described. Strategies and examples for the design of appropriate bifunctional chelating agents for the Tc/Re-tricarbonyl core are given. The functionalization of biomolecules such as tracers for the central nervous system (dopaminergic and serotonergic), tumour affine peptides (somatostatin receptors, neuroreceptors) and tumour binding single-chain antibody fragments is summarised. Where possible and appropriate, the in vitro and in vivo results in respect of these examples are compared with those obtained with classical (99m)Tc/(188)Re(V)- and (111)In-labelled analogues. The preclinical results show the in many ways superior characteristics of organometallic labelling techniques.

The identification rate of sentinel lymph nodes (SLNs) is variable because numerous different methods employing different tracers have been used for sentinel lymph node detection. The aim of this study was to determine the optimal technique for sentinel lymph node biopsy (SLNB).From May 1999 to December 2001, SLNB was performed for 376 patients with T1-3 and N0-1 primary breast cancer using blue dye alone, radioisotope (RI) alone and combination of RI and blue dye. Two hundred sixty-eight patients underwent SLNB using blue dye alone. They were divided into 4 groups (Group A: n=50; peritumoral injection, Group B: n=83; the first half to receive subareolar injection, Group C: n=83; the second half to receive subareolar injection, and Group D: n=52; small incision according to an axillary skin landmark). One hundred eight patients underwent SLNB using RI. Tin colloid was used in 49 cases (Tin Colloid Group) and phytate in 59 cases (Phytate Group). Among them, 29 patients underwent injection of RI alone and 79 patients received a combination of RI and blue dye.The identification rates of SLN using blue dye alone were 60%, 82%, 92% and 79% in Groups A, B, C and D, respectively. The identification rates of SLN in patients receiving RI alone and in those receiving combination of RI and blue dye were 40% and 89%, respectively, in Tin Colloid Group, and 92% and 94%, respectively, in Phytate Group.When using blue dye alone, subareolar injection provided a better identification rate than peritumoral injection. The combination of peritumoral phytate and subareolar blue dye provided the best identification rate (94%) in all the groups. The combination of intraparenchymal phytate and subareolar blue dye was the most efficient technique for sentinel node biopsy in breast cancer patients.

Although lymphoscintigraphy is a useful method of detecting the sentinel nodes of malignancy, conventional lymphoscintigraphy images only the sentinel nodes without revealing their anatomical location. We, therefore, used scattered photons to attempt to outline the body contours of patients with either breast or esophageal cancer. Lymphoscintigraphy was performed 3 to 4 hours after the injection of 111 MBq of 99mTc tin colloid into the peritumoral region. Images were obtained with dual-energy windows of 130 to 150 keV for the primary photons and 70 to 110 keV for the scattered photons. The images constructed from the scattered photons clearly showed the contours of the body, and the fusion images constructed from the primary and scattered photons allowed for easy identification of the location of the sentinel nodes. The results of this study confirm that images obtained from scattered photons on lymphoscintigraphy are helpful in identifying the anatomical location of sentinel nodes.

Objective. A retrospective study of the validity of combined bone scintigraphy (BS) and immunoscintigraphy (IS) using 99mTc-labelled murine antigranulocyte antibodies (MAB) and magnetic resonance imaging (MRI) in chronic post- traumatic osteomyelitis. Design and patients. The results of MRI and combined BS/IS of 19 lesions in 18 patients (13 men, 5 women; mean age 45 years, range 27–65 years) were independently evaluated by two radiologists and one nuclear medicine physician with regard to bone infection activity and extent. The patient group was a highly selective collection of clinical cases: the average number of operations conducted because of relapsing infection was eight (range 2–27), the average time interval between the last surgical intervention and the present study was 6.5 years (range 3 months to 39 years), and from the first operation was 14 years (range 1.5–42 years). Interobserver agreement on MRI was measured by kappa statistics. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated for MRI and the nuclear medicine studies. Results. For MRI/nuclear medicine, a sensitivity of 100%/77%, a specificity of 60%/50%, an accuracy of 79%/61%, a PPV of 69%/58% and a NPV of 100%/71% were calculated. Four MR examinations were false positives because of postsurgical granulation tissue. A high degree of interobserver agreement was found on MRI (κ=0.88). A low-grade infection was missed on two scintigrams, while four were false positive because of ectopic haematopoietic bone marrow, and in one examination the anatomical distortion resulted in an inaccurate assignment of the uptake leading to false positive findings. Image analysis was frequently hindered by susceptibility artefacts due to residual abrasions of metallic implants after removal of orthopaedic devices (15/18 patients); this led to limited assessment in 17% (3/18 patients). Conclusion. Acute activity in a chronic osteomyelitis can be excluded with high probability if the MRI findings are negative. In the first postoperative year fibrovascular scar cannot be distinguished accurately from reactivated infection on MRI and scintigraphy may improve the accuracy of diagnosis. MRI is more sensitive in low-grade infection during the later course than combined BS/IS. Scintigraphic errors due to ectopic, peripheral, haematopoietic bone marrow can be corrected by MRI.

We report a method for detection of deep venous thrombosis with a technetium 99m-labeled peptide (DMP 444). The N-methyl-arginine-glycine-aspartic acid sequence on DMP 444 binds the glycoprotein IIb/IIIa receptor on activated platelets (inhibition constant [IC50] for fibrinogen binding = 6 nmol/L).DMP 444 (23 to 27 mCi) was injected into 11 patients with clinical suspicion of deep venous thrombosis, diagnostic confirmation by ultrasound, and a positive D-dimer test result. Planar images in the anterior and posterior projections were obtained at 10 to 40 minutes, 50 to 80 minutes, and 120 to 150 minutes after injection.No clinically significant adverse effects were noted after DMP 444 administration. One patient (excluded from the analysis) withdrew consent, so image acquisition was not complete. By 10 to 40 minutes after injection, 8 of 10 patients demonstrated an area of increased activity that was clearly related to the abnormality noted on ultrasound. Most patients were taking warfarin (Coumadin) and heparin (n = 8) or heparin (n = 1) and warfarin (n = 1) alone at the time of the imaging. The average time from onset of symptoms to injection of DMP 444 was 5 days (range 1 to 18 days).These preliminary human studies indicate that DMP 444 is safe and may be of value in the diagnosis of deep venous thrombosis.

The status of the sentinel lymph node (SLN) can reflect the status of other lymph nodes in breast cancer. The efficacy of dye injection and radiolabeled tin colloids for the accurate identification of the SLN was investigated. The indications for SLN biopsy for determining clinical nodal status were also investigated.A total of 108 patients with breast cancers less than 5 cm were enrolled. Ninety-six patients were clinically node negative and 12 were node positive. About 2 hours before surgery, 1 to 2.5 ml of 99m-technetium-labeled tin colloid was injected around the tumor. Just before the operation, dye was also injected into the tissue surrounding the tumor. Six clinically node negative patients were omitted from the dye-injection process. The SLN was identified as a lymph node with extremely high radioactivity using a gamma probe or a gamma counter. Complete axillary dissection was performed and the metastatic status investigated by hematoxylin and eosin staining.In clinically node negative patients undergoing dye-injection, the SLN was identified in 89 of 90 patients (98.9%), and there was only one patient with lymph node metastasis outside the SLN. However, in clinically node positive patients undergoing dye-injection, the identification rate of the SLN was 66.7% (8 of 12 patients) and there was one patient with lymph node metastasis outside the SLN (12.5%). Without dye-injection, the SLN could be detected in 4 of 6 patients (66.7%).Successful identification of the SLN with tin colloid requires concomitant dye-injection and candidates for SLN biopsy should be restricted to clinically node negative cases.

The aim of this study was to obtain quantitative iodine-123 brain single-photon emission tomographic (SPET) images with scatter and attenuation correction. We used a triple-headed SPET gamma camera system equipped with fan-beam collimators with a technetium-99m line transmission source placed at one of the focal lines of the fan-beam collimators. Four energy windows were employed for data acquisition: (a) 126-132 keV, (b) 132-143 keV, (c) 143-175 keV and (d) 175-186 keV. A simultaneous transmission-emission computed tomography scan (TCT-ECT) was carried out for a brain phantom containing 123I solution. The triple energy window scatter correction was applied to the 123I ECT data measured by means of the windows (b), (c) and (d) acquired by two detectors. Attenuation maps were reconstructed from 99mTc TCT data measured by means of the windows (a), (b) and (c) acquired by one detector. Chang's iterative attenuation correction method using the attenuation maps was applied to the 123I ECT images. In the phantom study cross-calibrated SPET values obtained with the simultaneous mode were almost equal to those obtained with the sequential mode, and they were close to the true value, within an error range of 5.5%. In the human study corrected images showed a higher grey-to-white matter count ratio and relatively higher uptake in the cerebellum, basal ganglia and thalamus than uncorrected images. We conclude that this correction method provides improved quantification and quality of SPET images and that the method is clinically practical because it requires only a single scan with a 99mTc external source.

Preoperative cutaneous lymphoscintigraphy (LS) to identify sentinel (first-tier) lymph nodes was performed in 250 consecutive melanoma patients before wide local excision only or wide local excision with sentinel node biopsy.The location of the sentinel nodes was marked on the overlying skin in all patients. Whether or not tracer was present in second-tier lymph nodes on the delayed scans was recorded for each patient and related to the lesion site at which the tracer had initially been injected. For 100 consecutive patients the rate of tracer movement through the lymphatic channels was compared to the incidence of second-tier drainage.Second-tier nodes were visualized in all patients with melanomas on the leg and thigh, and in almost all patients with melanomas on the forearm and hand, but were seen less often in patients with more centrally located melanomas. There was a significant correlation between the rate of lymph flow and the incidence of demonstrable second-tier drainage.The results suggest that the physiology of the lymphatic system varies depending on the origin of the lymphatic vessel. These findings have important implications for application of the sentinel node biopsy technique in individual patients.

In this work an attempt is made to have a closer look at technetium species (TcX) induced by spinach plants, grown on TcO − 4 containing nutrient solutions. To this end, size-exclusion chromatography (SEC) and reversed-phase ion-pair chromatography (RP-IPC) were used: The performance was established with model compounds, i.e., anionic Tc-DTPA and cationic Tc-cyclam, used as mimics for TcX. Under the conditions applied, the information retrieved from high performance RP-IPC was minimal due to strong interactions of the technetium species with the Nucleosil C18 stationary phase. However, in low-pressure SEC non-size effects allowed differentiation of TcX into two distinct classes of technetium compounds, i.e., TcX1 and TcX2. From retention behavior in SEC, it was possible to speculate on the chemical properties of these two technetium species.

To study the relationship between tissue accumulation of Zinc (Zn) and neurodegeneration in the nigrostriatal dopaminergic pathway, 65Zn distribution in this pathway was examined after unilateral injection of 6-hydroxydopamine (6-OHDA) into the substantia nigra of rats. When 65ZnCl2 was intravenously injected 4 days after treatment with 6-OHDA, 65Zn was concentrated in the ipsilateral substantia nigra 6 days after 65Zn injection. On the other hand, 19 d after treatment with 6-OHDA, 65Zn distribution in the ipsilateral substantia nigra was decreased to the level of the contralateral one. When NH4(99)TcO4, which cannot go through the blood-brain barrier, was injected into rats 4 d after treatment with 6-OHDA, 99Tc was concentrated in the ipsilateral substantia nigra 30 min after 99Tc injection, but no longer detectable 6 d after injection. These results suggest that Zn is necessary for a repair process called replacement gliosis after the death of neurons and that excess Zn does not accumulate in the lesion after completion of the gliosis.

Soft-tissue vascular anomalies such as haemangioma and vascular malformation are treated by surgical resection, arterial embolization or sclerotherapy. Because the effect of sclerotherapy, i.e. the percutaneous injection of sclerosing agents, depends on intralesional haemodynamics, estimation of flow characteristics of soft-tissue vascular anomalies is essential when determining appropriate patient management. However, lesions are at present divided into only two groups: high flow and low flow. We have developed a new method, direct puncture scintigraphy, to evaluate in detail the haemodynamics of vascular anomalies under conditions simulating sclerotherapy. Twenty-six soft-tissue vascular anomalies in 21 patients were studied. After 30 MBq of technetium-99m Sn colloid was injected percutaneously into the intravascular space of the lesion, dynamic imaging was performed for 5 min. A time-activity curve for the lesion was generated, with the infiltrated activity on injection subtracted. A monoexponential curve was fitted to the declining phase of the time-activity curve, and mean vascular transit time (MTT) was obtained. The lesions were classified into high-flow and low-flow lesions based on radionuclide angiography with intravenous injection of 99mTc-labelled red blood cells, and estimates of MTT in the two groups were compared. The imaging procedures were carried out with no major complications, and broad intralesional diffusion of 99mTc-Sn colloid was achieved in most lesions. The high-flow lesions (six lesions) had a short MTT, ranging from 1.6 to 3.4 s, while the low-flow lesions (20 lesions) had a longer MTT, with no overlap between the groups. MTT showed a wide range in low-flow lesions: it was less than 30 s in six lesions and more than 10 min in five other lesions. Direct puncture scintigraphy provides a quantitative indicator of the flow characteristics of soft-tissue vascular anomalies, and may aid in determining treatment strategies for patients with vascular anomalies.

We report on a case of thoracic esophageal cancer following total gastrectomy (rho-Roux-en-Y reconstruction) with metastasis to the mesojejunal lymph nodes. Subtotal esophagectomy with reconstruction using pedicled colon and dissection of two lymph node fields was performed. During the operation, we found three lymph nodes showing metastasis at the rho-Roux loop of the mesentery, and resected the rho-Roux loop. The route of the lymphatic drainage to the abdomen from the thoracic tumor seemed to have been changed by the prior gastrectomy. Based on the pathological findings, the case was diagnosed with T2N4M0, Stage IVa. We did not confirm that the distant metastases skipped the mesojejunal lymph nodes preoperatively; the distant metastases were detected accidentally by lymphoscintigraphy using technetium-99m tin colloid. We believe this case highlights the need for detailed examinations in esophageal cancer patients who have had prior gastrectomy.

An alkaline kit formulation (pH 9) to obtain [99mTc]MAG3 with radiochemical puritives over 98% has been developed, avoiding the addition of filtered air to the vial, the use of large amounts of99mTc activity (i.e., 3.7 GBq) or the reconstitution of large volumes. The use of this radiopharmaceutical in mice showed a minimal accumulation in the hepatobiliary system (0.37±0.3% I.D., 1 h postinjection). However, in rabbits we always obtained good image quality.

A patient is described with a rapidly progressive Kaposi's sarcoma following immunosuppressive therapy with fludarabine monophosphate (FAMP) for chronic lymphocytic leukemia. The development of this tumor was accompanied by progressive thrombocytopenia, due to trapping of the platelets in the Kaposi sarcoma, without signs of consumptive coagulopathy or microangiopathic hemolytic anemia. This sequestration process might be caused by the abnormal structure of the tumoral vessels, leading to exposure of subendothelial structures like collagen, von Willebrand's factor, and tenascin to the vessel lumen. A severe immunosuppression due to the lymphocytotoxic effect of FAMP on several T-cell subpopulations was seen. This case confirms the importance of immunosuppression as a co-factor in the development of Kaposi's sarcoma also in HIV-negative patients, and adds Kaposi's sarcoma to the differential diagnosis of thrombocytopenia in immunosuppressed patients.

Splenosis is defined as the heterotopic autotransplantation of splenic tissue. The main cause of splenosis is splenic rupture following abdominal trauma, in which fragments of splenic tissue are seeded throughout the peritoneal cavity. Demonstration of splenosis by scintigraphy or CT imaging has been reported, but there is no previous report of simultaneous demonstration by SPECT and CT imaging. Autotransplantation of splenic tissue in the abdominal cavity forms a solid tumor-like image on CT and is difficult to differentiate from other abdominal masses. In such cases, SPECT demonstration of splenosis is very important for identification of its exact site. A case report of splenosis is presented, in which simultaneous demonstration by SPECT and CT was performed. This was confirmed at laparotomy for gastrectomy.

Wandering spleen is the term commonly applied to splenic hypermobility that results from laxity or maldevelopment of its suspensory ligaments. It comes to medical attention usually as an abdominal mass, or when the spleen undergoes torsion. Diagnosis on clinical grounds alone is rarely made, and ultrasonography, CT and MRI findings have no specific characteristics for this condition. 99mTc-labeled colloid taken up by the spleen may provide a specific diagnosis. We report a case of wandering spleen, in which the preoperative diagnosis was made on the basis of sequential liver-spleen scintigraphy with 99mTc-Sn-colloid and blood-pool scintigraphy with 99mTc-RBC. This is a rare case, in which hypermobility was assessed by sequential 99mTc-Sn-colloid scintigraphy, and to our knowledge, is the first case in which 99mTc-RBC scintigraphy provided useful information on splenic blood volume and its location.

The location of a small lesion must be precisely identified during laparoscopic surgery. A gamma probe that is usually used for navigating sentinel lymph nodes was evaluated for its usefulness in locating small gastrointestinal lesions (14 gastric and 10 colonic). A total of 2 mCi of a Tc(99m)-labeled rhenium colloid was injected endoscopically around a tumor 16 h prior to surgery. During operation, the abdominal cavity was scanned using a handheld gamma probe (Navigator GPS, Tyco HealthCare, Norwalk, CT, USA). In all cases, the injection site was identified as the highest spot in the abdominal cavity, with 2585 counts per second on average (range, 910-8800 counts per second). The highest count in a lymph node was 637 per second on average. The gamma probe is a useful tool for identifying small gastrointestinal lesions during open and laparoscopic operations.

For the recognition and characterisation of oesophageal motor disorders, manometry represents the most reliable tool but yields no information on bolus transport. The transport can be quantitated by radionuclide techniques. The patient is positioned supine beneath a gamma-camera and instructed to swallow a radiolabelled bolus in a single gulp. Using a marker over the cricoid and the activity in the stomach as landmarks, regions of interest are drawn representing the upper, middle and lower third of the oesophagus and the gastric fundus. Activity-time curves enable one to recognise the clearance patterns in these regions. In combination, manometric and radionuclide transit studies recognise a higher number of motor disorders than either procedure alone. Radionuclide methods also are the most reliable and sensitive to quantitate gastric emptying. Procedure, meal size and composition as well as patient position must be standardised and correction techniques applied. The emptying of solid and liquid meal constituents can be evaluated concomitantly. Solids start to empty only after a lag phase of varying extent. With semi-solid meals, which are emptied at the same rate as solid meals of identical composition in the postlag phase, the recording time can be considerably shorter. Besides gastric emptying, the amplitude, frequency and propagation velocity of antral contractions can be recorded using serial images of short frame time and specially devised analytic techniques.

A SORB-GEL method has been worked out for analysing 99mTc-labelled compounds which (in a few minutes) enables the pertechnetate content to be determined in a preparation. The method is based upon a different tupe of behaviour of 99mTc-labelled compound, pertechnetate in the columns packed with Sephadex G-10, and with alumina during elution with saline.

We hereby describe a patient with amyloidosis complicated by reversible functional asplenia and spontaneous rupture of the liver with subcapsular hematoma which resolved completely with conservative therapy. These two rare findings may result from extensive vascular amyloid in this patient.

Whole body bone scanning with 99mTc-labelled phosphates is now well established in routine clinical practice. It is the most sensitive indicator of early pathology in the skeleton and it remains a non-invasive, safe, and easy procedure. It has passed the test of time and it is unlikely to be replaced even by the most modern computerised axial tomography techniques. The unique ability to display a high resolution image of the entire skeleton in 20 minutes is largely responsible for its wide clinical acceptance. The main disadvantage of the technique—the inconvenient waste of time, usually three hours, between tracer injection and actual image procedure-can now be overcome by utilising superior radio-pharmaceuticals and data processing techniques.

The effect of iron on the liver function was studied in rats. A total of 40 rats were divided into four groups. Group 1 was given iron; Group 2, carbon tetrachloride; Group 3, a combination of iron and carbon tetrachloride; and Group 4 was the control. The changes in liver function were evaluated by using hepatobiliary and liver scintigraphy as the index of hepatocyte function and reticuloendothelial system function, respectively. Determination of liver CT number and a histological study were made at the same time. The administration of iron activated the reticuloendothelial system function per unit of liver weight. However, because of the decrease in liver weight, the total reticuloendothelial system function did not change at all. In the group given iron and carbon tetrachloride, liver cirrhosis and siderosis in the reticuloendothelial system occurred. Dysfunction in the reticuloendothelial system was more severe in this group than in the group given carbon tetrachloride only, by hepatocyte dysfunction was more mild. It is doubtful that the administration of iron after liver dysfunction had developed, which caused acceleration of fibrosis and reduction of liver blood flow, led to the enhancement of the reticuloendothelial system dysfunction.

A new purity control method was developed in order to assure the radiochemical purity of thiamine pyrophosphate-Sn-99mTc. The method described consists in ascending cromatography using Whatman No 1 for support and 5% sodium citrate as solvent. It is capable of detecting free99mTcO4− and colloid formation, the most frequent impurities found in99mTc radiopharmaceuticals.

Human autologous leucocytes can be simply and reproducibly labelled by phagocytic engulfment of technetium 99m stannous colloid with high leucocyte-labelling efficiency (LLE), similar human biodistribution to indium-111-oxine labelled leucocytes and good cell viability. A mean particle size of 2.1 microns is optimal for phagocytosis and the most important parameter in maintaining reproducibly high neutrophil uptake. It is more critical than hitherto appreciated. When such variables as type of colloid, purity of starting materials, speed of mixer rotation when preparing colloid and labelling leucocytes, heparin concentration, freshness of colloid preparation, type of sterilising membrane filter used and incubation time of cells with colloid are rigidly controlled, consistent labelling efficiencies in excess of 90% can be obtained with neutrophil predominance. The lyophilised kit tested produced suboptimal results.

Paper and TLC chromatographic methods have been evaluated for the control of the labeling and stability of eight Tc-radiopharmaceuticals. The different supporting media and eluents have been studied and the most suitable methods have been classified according to their usefulness, reliability and rapidity. Moreover the artefacts encountered have been investigated. Alumina is found not suitable for its interference with TcO 4 − . Acetate buffer seems to be labeled by TcHR inducing frequently subsequent smearings. Methyl ethyl ketone is optimal for the quantification of TcO 4 − except in Tc-HIDA. TcHR never migrates as well as Tc-S Coll, Tc-MAA and Tc-HSA. The well-defined separation of TcO 4 − and TcHR from the radiopharmaceutical often requires a two-step method.

Lymphoscintigraphy using 99mTcSb2S3 colloid was performed in 32 patients with malignant melanoma. Subcutaneous injections were made peritumorally in 20 patients and dorsopedally in 12 patients. Regional lymph node dissections were carried out on the following day in 16 patients and the resected lymph nodes were weighted, measured for radioactivity, and examined by light microscopy. Lymph flow to regional lymph nodes was shown in all but 2 patients. Twenty-nine of 239 lymph nodes contained metastases. Radioactivity was demonstrated in 17 of these nodes. In 5 of 11 patients with metastatic disease, the highest uptake was found in cancerous lymph nodes. The specific activity-uptake distribution in isolated ilio-inguinal lymph nodes after a dorsopedal injection was log-normal with a mean of 0.05%/g indicating a good saturation of colloid particles. This investigation concludes that the observed lymph flow directions in patients injected peritumorally are of value for the follow-up. Quantitative lymphoscintigraphy in patients with melanoma of the lower extremities is, however, of no value for excluding ilio-inguinal lymph node metastases.

Autologous leucocytes were labelled in whole blood by phagocytic uptake of 99mTc-stannous colloid. This colloid has a mean particle size of 1.5 micron and labels leucocytes with 81% efficiency. Individual cell uptakes were: granulocytes 42%, monocytes 39%. Isotonic sodium citrate added after the labelling procedure did solubilise excess colloid but was not necessary for adequate removal of excess colloid. Labelled leucocytes were shown in vitro to be viable and maintain normal bactericidal and chemotactic capacity. Biodistribution, clearance rates and dosimetry are presented. These results indicate that autologous leucocytes can be efficiently labelled with 99mTc-stannous colloid with good residual cell function.

A study was made of 26 patients diagnosed as phase I reflex sympathetic dystrophy. In all of them, a bone:soft tissue uptake index was quantified by scintigraphic scanning before treatment and 3 months later. Eighteen patients were treated with 100 MRC units salmon calcitonin, followed by 500 mg elemental calcium 4 hours after hormone administration. The treatment was administered 10 days a month separated by intervals free of therapy. The other 8 patients were treated without interruption with 500 mg naproxen every 12 hours. In the group treated with calcitonin and calcium, the uptake index declined from 13.3 +/- 8.2 to 4.1 +/- 1.8 (p less than 0.001). The uptake index rose from 2.1.3 +/- 17.7 to 31.1 +/- 23.0 (NS) in the naproxen group. Using the Student t-test for paired samples to evaluate individual changes, a highly significant difference was reached (p less than 0.005) in the calcitonin-calcium group. The difference was also significant (p less than 0.01) in the naproxen group, but it was negative (t = 3.620). These results confirm the efficacy of treating reflex sympathetic dystrophy with calcitonin and calcium and the superiority of this treatment as compared with nonsteroidal anti-inflammatory drugs.

In rat the uptake of colloids by the femur and tibia is dependent on bone plasma flow even if other factors modulate the relationship. We warn Nuclear Medicine scientists against the use of colloid uptake measurement as a marker of the bone macrophagic population, especially in situations associated with modified bone plasma flow.

The degree of deposition of small-particle colloids such as 99mTc-antimony sulfide colloids (ASC-group) and 99mTc-rhenium colloid (Tc-Re) in the bone marrow and lymph node was studied. H-ASC that was prepared in our laboratory was concentrated to a higher degree both in the bone marrow and lymph nodes, compared with other colloids. The H-ASC were mostly from 5 to 12.5 nm and the shape was uniform and spherical. The degree of deposition of Tc-Re in rabbit lymph nodes was not higher, however, the label was considered to be valuable clinically. The degree of deposition of Tc-Re in the bone marrow was not satisfactory. The size of Tc-Re was much smaller than H-ASC, ranging from 3 to 5 nm. From these results, it is considered that factors affecting deposition in the marrow are not identical to those in the lymph nodes.

A total of 2530 consecutive bone scans were examined to evaluate the number and the type of soft tissue neoplasms detected with bone-seeking phosphonates. Sixty-eight primary or secondary soft tissue neoplasms of 63 patients accumulated 99mTc -methylene diphosphonate and 2 accumulated 99mTc -diphosphonate, and one metastasis was seen as a nonactive 'cold' focus in the urinary bladder. The localization of tumors was: 19 in the lung, 15 in the liver, 11 in the kidney, 10 in the peritoneal cavity or ascites, 5 in the large bowel, 4 in the vascular or lymphatic system, 3 in the connective tissue or muscles, 2 in the ovary, 1 in the urinary bladder, and 1 in the brain. Our results differ in many respects from those reported in the literature. The causes of the differences are discussed.

Whereas normal liver and spleen scintiphotos with 99mTc- tin colloid are characterized by homogenous distribution of radiocolloid in the liver and slight uptake of radiotracer over the spleen in the anterior view, this report demonstrates that there is high radiotracer uptake in the spleen and slight uptake in the posterior view in a case of situs inversus.