TlCl Research Articles

Species of molybdenum, thallium, and tellurium in ferromanganese crusts of oceanic Seamounts

The species of molybdenum, thallium, and tellurium in standard technological samples of ferromanganese crusts from the Magellan Seamounts in the Pacific Ocean were studied by means of analytical electron microscopy and chemical analysis. In the initial samples and in the products of their acid treatment, some ultramicroscopic inclusions of molybdenite, thallium oxide and chlorite, and tellurium oxide were found. The origin of the molybdenite is supposedly related to the sedimentation of organic matter particles from oceanic water, thus, forming a local reducing environment. The presence of thallium chloride in the crusts correlates with the existence of this compound in oceanic waters; the same is true for thallium and tellurium oxides. The data presented show that, in ferromanganese crusts, along with the sorbed forms of the microelements considered, their own mineral phases are present.

Coronary artery disease investigated using 99mTc‐tetrofosmin myocardial SPECT

Coronary artery disease can be diagnosed from stress and delayed images of myocardial single photon emission computed tomography (SPECT) using technetium-99 m-tetrofosmin (TcTF). However, the negative predictive value of stress SPECT images after a single injection of a low tracer dose remains unknown. Thus, the present study investigates whether normal stress SPECT results predict event-free survival. We screened 302 consecutive patients who were randomly assigned to two groups for myocardial ischaemia using either stress SPECT with a low dose of TcTF (296 MBq, TcTF group, n = 150) or stress together with rest SPECT using thallium(201) chloride (TlCl, 111 MBq; TlCl group, n = 152) as the tracer. A total of 80 patients with abnormal SPECT findings were excluded and the remaining 222 with normal results (age, 66.5 +/- 0.7 years; TcTF/TlCl, 112/110) were enrolled in the present study and followed up for 401 +/- 9 days, with the endpoint being ischaemic cardiac events. The incidence of cardiac events did not differ between the two groups (0.9% and 0.0% in TcTF and TlCl groups, respectively). The cost and duration of TcTF and TlCl SPECT examinations were about 425 and 603 Euros and 50 and 280 min, respectively. The negative predictive values of stress SPECT using a low dose of TcTF and of combined stress and rest SPECT using TlCl did not differ and both were clinically acceptable. Thus, stress SPECT using low dose TcTF is useful in screening patients for myocardial ischaemia.

Crystal structure and investigation of phase transitions in hexa (2 amino-indolinium) dodécachlorobithallate(III) and quinolinium tetrachlorothallate(III)

Two new thallium containing salts with different aryl ammonium cations have been prepared and characterized by X-ray crystallography, infrared spectroscopy and dielectric measurements. The salt [C 8N 2H 8] 6Tl 2Cl 12 (1) crystallizes in the monoclinic system with space group Pn. The unit cell dimensions are: a = 15.120(5), b = 11.825(5), c = 17.167(5) Å, β = 104.460(5)° with Z = 2, D calcd = 1.818 g cm −3, R = 0.0369. The structure consists of 2 amino-indolinium cations and monomeric TlCl 6 3 - anions. The TlCl 6 3 - has a strongly octahedral geometry presenting five short and one long (Tl1–Cl13 = 2.739(5) and Tl2–Cl26 = 2.684(5) Å) Tl–Cl bonds. The presence of multiple hydrogen bonds is considered to be responsible for the octahedral distortion. However, the second compound [C 9H 8N]TlCl 4 (2) crystallizes in the Pna2 1 orthorhombic space group, with a = 9.253(1), b = 9.799(1), c = 14.558(2) Å, Z = 4, D calcd = 2.397 g cm −3, R = 0.0608. The structure of the quinolinium tetrachlorothallate(III) is characterized by tetracoordinate thallium, forming a regular tetrahedral TlCl 4 with Tl–Cl distances between 2.366(2) and 2.451(3) Å. The structure consists of quinolinium cations separating chains of TlCl 4 - tetrahedra, these chains being perpendicular to the c axis. Infrared spectra confirm the presence of the organic cations. Differential scanning calorimetry study was carried out. Electrical measurements were performed to discuss the mechanism of the phase transition.

Thallium-201 SPECT predicts response to intensity-modulated radiation therapy for recurrent oral squamous cell carcinoma

The aim of this study was designed to investigate the usefulness of thallium-201 single photon emission computed tomography (SPECT) in predicting response of intensity-modulated radiation therapy (IMRT) for recurrent oral squamous cell carcinoma (OSCC). Thirty-one patients with histologically proven recurrent OSCC were recruited. Before IMRT, all patients underwent SPECT at 15 min and 120 min after intravenous injection 111 MBq of thallous chloride ((201)Tl). Tumour uptake was measured with the semiquantitative early ratio (ER), delayed ratio (DR), and retention index (RI). The patients were classified into responder (complete response and partial response) and non-responder (stable disease and progressive disease) groups according to the tumour response evaluated by the Response Evaluation Criteria in Solid Tumors guidelines. As comparing DR and RI between the two groups, both parameters were significantly higher in the responder group. When a DR of 1.75 was used as a cutoff value for the responders, the receiver operating characteristic (ROC) analyses revealed sensitivity and specificity of 79% and 75%, respectively. At a cutoff value for the responders of a RI of 78.5%, the ROC analyses showed sensitivity and specificity of 95% and 83%, respectively. Our results suggest that (201)Tl-SPECT, as measured by the DR or RI has clinical potential in predicting response of IMRT for patients with recurrent OSCC. The ROC curve analyses further suggest that RI may be superior to DR in distinguishing responders from non-responders.

Blood Flow Redistribution During Exercise Contributes to Exercise Tolerance in Patients With Chronic Heart Failure

It is widely known that blood flow redistribution is impaired in patients with chronic heart failure (CHF). However, the relationship between exercise tolerance and the degree of blood flow redistribution is not fully understood. Whole-body thallium-201 chloride ((201)Tl) scintigraphy can estimate blood flow distribution. This study will evaluate the relationship between exercise tolerance and blood flow redistribution using whole-body scintigraphy in patients with CHF. Exercise stress whole-body thallium scintigraphy was performed in 19 patients with CHF (mean ejection fraction: 33.0%; peak oxygen uptake: 15.5 ml x min(-1) x kg(-1)). Blood flow redistribution was quantified by comparing the regional thallium count (count/pixel) in the thigh and arm. We then assessed the relationship between these parameters and parameters obtained from cardiopulmonary exercise testing. (201)Thallium-chloride uptake in the thigh increased during exercise compared to rest (p<0.05), while its uptake in the arm was not different between exercise and rest. Increased (201)Tl uptake in the thigh during exercise was positively correlated with exercise tolerance (r=0.689). In contrast, (201)Tl uptake in the arm was not correlated with exercise tolerance. By using this method, it is concluded that blood flow redistribution to the exercising muscle increases as the exercise tolerance increases in patients with CHF.

Raman scattering of [formula omitted

We have studied magnetic excitations in the coupled spin dimer system Tl ( Cu 1 - x Mg x ) Cl 3 by means of Raman scattering. A broad two-magnon Raman band extending from 2 Δ to about 150 cm - 1 is observed at low temperatures, where Δ is the spin-gap energy. With increasing nonmagnetic impurity Mg, the intensity of the broad Raman band weakens and its onset energy, 2 Δ , shifts to higher energy. The quasi-elastic scattering appears and the onset of the two-magnon Raman band gets smeared when x = 0.05 . The Raman spectrum hardly changes when a magnetic field is applied, which indicates a creation of a pair of triplets whose total S is zero in the second-order Raman process.

Impurity- and field-induced magnetic orderings in doped quantum antiferromagnet [formula omitted

TlCuCl 3 is a spin- 1 2 magnetic insulator with a spin gap Δ / 2 μ B = 5.5 T . Its magnetic properties are described by a three-dimensionally coupled spin dimer model. Tl ( Cu 1 - x Mg x ) Cl 3 doped with nonmagnetic Mg 2 + undergoes impurity-induced magnetic ordering. Because a finite gap for triplet excitations still remains, this doped system can also undergo magnetic-field-induced magnetic ordering. In order to investigate the phase diagram of TlCu 1 - x Mg x Cl 3 with x ∼ 0.01 , we performed specific heat measurements and neutron scattering experiments in a magnetic field. It was found that impurity- and field-induced ordered phases are the same, and that the gapped spin liquid state observed in pure TlCuCl 3 is completely wiped out by such a weak doping.

Neurocirugía radiodirigida: una aplicación novedosa de la Medicina Nuclear

Brain tumours show uptake with Thallium-201 Chloride with high target/background rate and they would benefit from radioguided surgery. We report a patient with a brain tumor that was Thallium positive in a brain SPECT. On the next day in the operating room we injected 50 MBq of Thallium-201. At 40 minutes we confirmed tumour uptake with a gamma-probe and with a biopsy sample. After brain tumor resection was completed by conventional method, we found pathologic activity in tumoral bed with the gamma probe, that showed persistence of increased activity. After a new evaluation, residual tumor tissue was located in the pathological uptake area and was removed. Control CT showed complete resection, although the Thallium SPECT carried out after surgery showed faint uptake in the anterior pole of the surgical bed. Radioguided surgery was valuated as a useful and promising technique by the neurosurgeon.

Diaphyseal medullary stenosis with pleomorphic malignant fibrous histiocytoma of the bone:99mTc hydroxymethylenediphosphonate and201Tl chloride scintigraphy findings

Diaphyseal medullary stenosis (DMS) is an extremely rare hereditary bone dysplasia, which was first described by Arnold in 1973. DMS has a high incidence of pleomorphic malignant fibrous histiocytoma (MFH). In this paper, we report the imaging findings of DMS with pleomorphic MFH of the bone, mainly describing 99mTc hydroxymethylenediphosphonate (HMDP) and thallium-201 (201Tl) chloride scintigraphy findings. On 99mTc HMDP scintigraphy, focal increased uptake area of the right femur corresponded to the area of bone marrow invasion of the tumor and bone infarction. The mechanism of the uptake of 99mTc HMDP to the extraosseous lesion was not clear. On 201Tl chloride scintigraphy, the increased uptake of the periphery of the mass seemed to reflect the aggressiveness of invasion and the cellularity.

DYNAMIC, EQUILIBRIUM AND HUMAN STUDIES OF ADSORPTION OF 201Tl BY PRUSSIAN BLUE

Prussian blue is the recommended but infrequently required antidote for radiocesium and thallium chemical poisoning. Conceivably, its most frequent application will be the decontamination of radiothallium (thallous chloride) from human body following myocardial scintigraphy. Dosage schedule and physicochemical parameters of interaction with radiothallium, however, need to be defined, as the known data is inadequate on this account. The objective of the present study is to create physiologically relevant and mathematically rigorous data on interaction of Prussian blue with Tl, to estimate dosage schedule of Prussian blue suitable for myocardial scintigraphy, and to perform preliminary human studies to evaluate the efficacy of the antidote in reducing the considerable radiation burden imparted by this radiotracer. Adsorption efficacy of Prussian blue for radiothallium was found to be more than 95% at basic (intestinal) pH even at low concentrations and in presence of the physiological cations, potassium and sodium. Isotherm analysis and derivations using Langmuir, Bajpai, Lagergreen, and Freundlich equations suggest a favorable adsorption of Tl on Prussian blue with qmax being 5,000 MBq g. Based on these findings and clinical considerations, particularly preferential gall bladder excretion and enterohepatic recycling of radioactive thallous chloride, a dose of 100 mg Prussian blue with every major meal for 3 days was considered adequate for the purpose. Our experience with the first two patients (serving as their own self-controls) suggests that Prussian blue therapy is a safe and effective method to significantly reduce radiation burden imparted by thallium myocardial scintigraphy.

Evaluation of No-Reflow Phenomenon Using 201TlCl/123I-BMIPP Dual-isotope Myocardial SPECT

We assessed the usefulness of (201)thallous chloride (TlCl)/(123)I-beta-methyl iodophenyl pentadecanoic acid (BMIPP) dual-isotope single-photon emission computed tomography (SPECT) to identify the "no-reflow phenomenon," defined as inadequate myocardial perfusion through a given segment of the coronary circulation without angiographic evidence of mechanical vessel obstruction. (201)TlCl/(123)I-BMIPP SPECT was performed in 73 patients within approximately 1 week of initial acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI). We divided the left ventricular myocardium into 17 segments on each SPECT image and scored tracer accumulation in each segment with a five-point scoring system according to the American Heart Association criteria. Total severity scores were calculated by summing the scores for all 17 segments. The mismatch ratio between myocardial perfusion and metabolism was derived from the (201)TlCl and (123)I-BMIPP total severity scores: mismatch ratio=((123)I-BMIPP total severity score -(201)TlCl total severity score)/(123)I-BMIPP total severity score. Patients were classified according to Thrombolysis in Myocardial Infarction (TIMI) flow grade as having TIMI reflow grade 0-I (TIMI 0-I reflow group; n=11), II (TIMI II reflow group; n=17) and III (TIMI III reflow group; n=45). The TIMI III reflow group was subdivided into two groups with (201)TlCl total severity scores of < or =13 (TIMI III (A) reflow group; n=36) and > or =14 (TIMI III (B) reflow group; n=9), respectively. The mismatch ratios in the TIMI II (0.4 +/- 0.3) and TIMI III (0.4 +/- 0.2) reflow groups were significantly higher than that in the TIMI 0-1 reflow group (0.1 +/- 0.1, p<0.05). Although coronary angiography revealed TIMI III flow after reperfusion, the mismatch ratios in the TIMI III (B) reflow group (0.2 +/- 0.1) and in the TIMI 0-I reflow group (0.1 +/- 0.1) were significantly lower than that in the TIMI III (A) reflow group (0.4 +/- 0.2, p<0.01), reflecting noneffective recanalization (so called no-reflow phenomenon). (201)TlCl/(123)I-BMIPP dual-isotope myocardial SPECT reveals the biochemical degree of the no-reflow phenomenon, whereas coronary angiography shows recanalized vascular flow only. Dual-isotope myocardial SPECT might be useful for evaluating reperfusion therapy.

Contrast-Enhanced Magnetic Resonance and Thallium Scintigraphy in the Detection of Myocardial Viability A Prospective Comparative Study

The aim of the present study was to prospectively compare contrast-enhanced magnetic resonance imaging (CE-MRI) with single-photon emission tomography using (201)Thallium chloride (SPECT Tl) in the detection of myocardial viability. Patients with chronic coronary artery disease and systolic dysfunction defined by an ejection fraction (EF) <or= 45% were included. CE-MRI was performed 10-15 minutes after the administration of a gadolinium-based contrast agent using an Inversion Recovery Turbo FLASH (fast low-angle shot) sequence. A 4-hour rest redistribution protocol was used for SPECT Tl. Radionuclide ventriculography was used for the assessment of EF. Forty patients with an EF of 33.1 +/- 7.7% were included. Thirty-two underwent a follow-up examination after revascularization. Comparison of viability assessment was performed in 1360 segments. Agreement was noted in 1065 (78.3%) segments, resulting in a kappa value of 0.336. Discrepancies were observed in 96 SPECT Tl viable segments that were described as nonviable according to CE-MRI and in 199 SPECT Tl nonviable segments that were viable in the CE-MRI study. In patients undergoing the follow-up examination, EF increased by 5.5 +/- 7.3% (33.6 +/- 8.6% to 39.2 +/- 9.7%), but the relation between the amount of dysfunctional viable myocardium defined by both methods studied and the change in EF after revascularization was very weak and not statistically significant. Moderate agreement in the myocardial viability assessment between CE-MRI and SPECT Tl was observed. CE-MRI seems to be more accurate in identifying myocardial viability in inferior and inferolateral segments. We were unable to verify if either of the methods studied is useful for the prediction of EF improvement after revascularization.

Thallous chloride uptake and DNA profile in parathyroid adenomas

Thallium isotope scintigraphy is used to localize parathyroid adenomas but the mechanism underlying the technique is poorly understood. While larger adenomas are reliably localized the results are less certain for small tumours. This study explores the relationship between cellular DNA profile and thallium uptake (localization accuracy) in 24 parathyroid adenomas. The DNA profile was assessed using flow cytometry and standard subtraction thallium scintigraphy was performed before surgery. Fifteen of the 24 adenomas demonstrated excessive mitotic activity and 13 of these glands were accurately localized. Of the remaining nine glands, only five were localized accurately (P less than 0.01, chi 2 test including Yates' correction). This difference in thallium uptake could not be accounted for on the basis of gland weight. Thallium localization of parathyroid adenomas is related to mitotic activity. This may explain some of the limitations of this technique.

On the activity coefficients of charge-symmetrical ion pairs

The association constant K A of charge-symmetrical ion pairs in electrolyte solutions, obtained from experiments yielding the fraction present as free ions as a function of the electrolyte concentration α( c), is calculated from K A = (1 − α) f ip / α 2 cf ± 2. The activity coefficients of the free ions f ± are generally taken into account but those of the ion pairs f ip are commonly set equal to unity, for lack of better knowledge. Two methods for obtaining the latter quantity, one based on salting-out (in) and the other based on an analogy with zwitterions, are suggested for the calculation of f ip. The consequences are illustrated for cases taken from the literature of ion pairing of thallium (I) chloride in water and of sodium iodide and tetrabutylammonium bromide in acetonitrile that are characterized by low or moderate values of K A, and of magnesium sulfate in water that has a fairly high value of K A.

Solid state aggregation of lithium and thallium(I) bis(alkylamido)phenylboranes

The conversion of N, N′-dilithiobis(alkylamido)phenylboranes [RN–B Ph–NR]Li 2 (R = t Bu ( 1), i Pr ( 2)) to the equivalent dithallium(I) bisamides proceeds readily through the reaction with two molar equivalents of thallous chloride. The thallium amides [RN–B Ph–NR]Tl 2 (R = t Bu ( 3), i Pr ( 4)) have been prepared and characterized by 1H and 11B{ 1H} NMR. Single crystal X-ray structures of 2– 4 reveal the formation of aggregates in the solid state.

Thallium-201 chloride (Tl-201) accumulation and Na+/K+-ATPase expression in tumours of the head and neck

The purpose of this report was to evaluate the relationship between the tumour retention index of thallium-201 chloride (Tl-201) scintigraphy and the Na+/K+-ATPase expression in tumours of the head and neck. Tl-201 scintigraphy was performed in 146 patients (129 with malignant tumours, ten with benign tumours and seven with inflammation). The tumour retention index was obtained from the early and delayed dynamic Tl-201 scans. The Na+/K+-ATPase expression was evaluated immunohistochemically in 61 of 129 patients with malignant tumour. Furthermore, another 22 patients with benign tumour were evaluated immunohistochemically as a benign control. Comparison of the correlations between the grade of histopathological differentiation of tumour, the tumour retention index of Tl-201 scintigraphy and the Na+/K+-ATPase expression was performed. The grade of histopathological differentiation of tumour, the tumour retention index of Tl-201 scintigraphy and the expression of Na+/K+-ATPase showed a good correlation indicating that Na+/K+-ATPase plays an important role in transportation for Tl-201 to go through the tumour cell membrane. Na+/K+-ATPase is one of the most important factors for Tl-201 accumulation in tumour.

Incidentally detected parafalcine chondrosarcoma

Parafalcine chondrosarcoma is extremely rare, and may be difficult to differentiate preoperatively from falx meningioma. An 18-year-old woman presented with a parafalcine chondrosarcoma incidentally detected as a small lesion 2 years before admission, suggesting falx meningioma. Brain computed tomography and magnetic resonance imaging just before admission revealed the parafalcine lesion had increased by about nine times in volume during the last 2 years. Single-photon emission computed tomography (SPECT) after intravenous administration of both thallium-201 chloride ((201)TlCl) and N-isopropyl-p-[(123)I]iodoamphetamine ((123)I-IMP) demonstrated no abnormal uptake of either tracer. Histological examination revealed classic low-grade chondrosarcoma. Parafalcine chondrosarcoma should be considered at this site if relatively rapid growth is observed. SPECT using (201)TlCl and (123)I-IMP may be useful to discriminate parafalcine low-grade chondrosarcoma from meningioma or other tumours originating in this region.

Biasing effects on thallium and silver chlorides with dc/ac voltage

Comparison was made between crystals of thallium chloride and silver chloride on their biasing effects with dc/ac voltage. Previous reports say that, although their electrical conductivities are similar, the dominant charge carriers in the former are the Cl− ions while the Ag+ ions in the latter. The present dc/ac study demonstrates the following: for thallium chloride, although Cl− conduction may be dominant under low bias field, Tl+ conduction supercedes Cl− conduction when the bias field is enhanced. For silver chloride, Ag+ conduction is overwhelming within wide temperature range, to cause easy dielectric breakdown on dc biasing. Concerning the extrinsic conductivity seen at temperatures below 60°C (thallium chloride) or below 150°C (silver chloride), it is ascribed to grain-boundary related electron conduction, not to grain-boundary related Tl+ or Ag+ conduction as reported earlier.

Initial application of respiratory-gated 201Tl SPECT in pulmonary malignant tumours

Respiratory-gated thallium-201 chloride (201Tl) single photon emission computed tomography (SPECT) was used in preliminary investigations to reduce the adverse respiratory motion effects observed on standard ungated SPECT images and to obtain reliable fusion images with computed tomography (CT) in patients with malignant lung tumours. Fifteen patients with primary lung cancer (n=10) or metastatic lung tumours (n=5) underwent gated SPECT 20 min after intravenous injection of 148 MBq 201Tl, using triple-headed SPECT and laser light respiratory tracking units. Projection data were acquired by a step and shoot mode, with 20 stops over 120 degrees for each detector and a preset time of 30 s for each 6 degrees stop. Gated end-inspiratory and ungated images were obtained from 1/8 data centred at peak inspiration for each regular respiratory cycle and for the full respiratory cycle data, respectively. The degree and size of tumour 201Tl uptake were compared between these images by regions of interest (ROI) analysis. Gated SPECT images were registered with rest inspiratory CT images using an automated three-dimensional (3D) image registration tool. Registration mismatch was assessed by measuring the 3D distance of the centroid of 14 201Tl-avid peripheral tumours. Attenuation correction of gated SPECT images was performed using CT attenuation values of these fusion images. Gated SPECT images improved image clarity and contrast of tumour 201Tl uptakes compared with ungated images, regardless of the decreased count density due to the use of gated images. The lesion-to-normal (L/N) lung count ratios and ROI size in 18 well-circumscribed 201Tl-avid tumours were significantly higher and smaller on gated images (both P<0.0001). Gated images showed positive 201Tl uptakes in two small peripheral tumours, although negative on ungated images, and demarcated 201Tl-avid tumours from adjacent 201Tl-avid lymph node or surrounding focal 201Tl uptakes caused by other pathology, although these were not clearly demarcated on ungated images. On fusion images, gated images yielded a significantly better SPECT-CT matching compared with ungated images (P<0.0001). Fusion images accurately localized 201Tl uptakes of tumour/lymph node and other focal pathological/physiological conditions. Attenuation-corrected gated SPECT images further facilitated the detection of 201Tl uptake in small or deeply located lesions, with significantly increased L/N ratios. Gated SPECT images facilitate the detection of tumour 201Tl uptake and provide reliable SPECT-CT fusion images, which contribute to accurate interpretation and attenuation correction of Tl SPECT images.

Diagnostic value of thallium-201 chloride single-photon emission computerized tomography in differentiating tumor recurrence from radiation injury after gamma knife surgery for metastatic brain tumors

Object. The authors assessed the diagnostic value of 201Tl Cl single-photon emission computerized tomography (SPECT), performed after gamma knife surgery (GKS) for metastatic brain tumors in differentiating tumor recurrence from radiation injury. Methods. Of 6503 metastatic brain tumors treated with GKS, 201Tl SPECT was required in 72 to differentiate between tumor recurrence and radiation injury. When the Tl index was greater than 5, the lesion was diagnosed as a tumor recurrence. When the index was &lt; 3.0 it was called radiation injury. In cases with a Tl index between 3 and 5, 201Tl SPECT was repeated once per month until the Tl index was greater than 5 or less than 3. If the Tl index fluctuated between 3 and 5 for 2 months, the lesion was diagnosed as radiation injury. The final diagnosis was based on histological examination or clinical course. The sensitivity of the method was 91%; thus 201Tl SPECT is effective for differentiating between tumor recurrence and radiation injury in metastatic brain tumors treated with GKS. Caution is necessary, however, for the following reasons: 1) simple interinstitutional comparisons of Tl indices are not possible because measurement methods are institute specific; 2) steroid administration decreases the Tl index to a variable degree; and 3) a severe radiation injury lesion, as is often seen after repeated GKS or very high dose GKS, may have a Tl index greater than 5. Conclusions. Used with critical insight 201Tl Cl SPECT can be useful in distinguishing between tumor regrowth and radiation necrosis in patients with cerebral metastases.