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INTRODUCTION: Thallium-201 is a radionuclide that has previously been used clinically for myocardial perfusion scintigraphy. Although in this role it has now been largely replaced by technetium-99 m radiopharmaceuticals, thallium-201 remains attractive in the context of molecular radionuclide therapy for cancer micrometastases or single circulating tumour cells. This is due to its Auger electron (AE) emissions, which are amongst the highest in total energy and number per decay for AE-emitters. Currently, chemical platforms to achieve this potential through developing thallium-201-labelled targeted radiopharmaceuticals are not available. Here, we describe convenient methods to oxidise [201Tl]Tl(I) to chelatable [201Tl]Tl(III) and identify challenges in stable chelation of thallium to support future synthesis of effective [201Tl]-labelled radiopharmaceuticals. METHODS: A plasmid pBR322 assay was carried out to determine the DNA damaging properties of [201Tl]Tl(III). A range of oxidising agents (ozone, oxygen, hydrogen peroxide, chloramine-T, iodogen, iodobeads, trichloroisocyanuric acid) and conditions (acidity, temperature) were assessed using thin layer chromatography. Chelators EDTA, DTPA and DOTA were investigated for their [201Tl]Tl(III) radiolabelling efficacy and complex stability. RESULTS: Isolated plasmid studies demonstrated that [201Tl]Tl(III) can induce single and double-stranded DNA breaks. Iodo-beads, iodogen and trichloroisocyanuric acid enabled more than 95% conversion from [201Tl]Tl(I) to [201Tl]Tl(III) under conditions compatible with future biomolecule radiolabelling (mild pH, room temperature and post-oxidation removal of oxidising agent). Although chelation of [201Tl]Tl(III) was possible with EDTA, DTPA and DOTA, only radiolabeled DOTA showed good stability in serum. CONCLUSIONS: Decay of [201Tl]Tl(III) in proximity to DNA causes DNA damage. Iodobeads provide a simple, mild method to convert thallium-201 from a 1+ to 3+ oxidation state and [201Tl]Tl(III) can be chelated by DOTA with moderate stability. Of the well-established chelators evaluated, DOTA is most promising for future molecular radionuclide therapy using thallium-201; nevertheless, a new generation of chelating agents offering resistance to reduction and dissociation of [201Tl]Tl(III) complexes is required.
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Radioisótopos de Talio , RadioquímicaRESUMEN
BACKGROUND: Myocardial scintigraphy is defined as class IIb in the Japanese Circulation Society guideline for diagnosis of vasospastic angina (VSA). However, Caucasian guidelines had no classification of cardiac scintigraphy for diagnosis of VSA. OBJECTIVES: To clarify the clinical usefulness of myocardial scintigraphy, we analyzed the sensitivity and specificity of each cardiac scintigraphy. METHODS: We extracted the 136 papers of myocardial scintigraphy from the PubMed database from 1980 to 2018 in patients with VSA. Finally we analyzed the 88 papers including 33 papers of201-thallium (Tl), 10 papers of 123I beta-methyl 15-para-iodophenyl 3(R, S)-methylpentadecanoic acid (BMIPP), 9 papers of 123I-metaiodobenzylguanidine (MIBG), 4 papers of 99mTc-sestamibi (MIBI: methoxy-isobutyl-isonitrile), and 2 papers of tetrofosmin to investigate the sensitivity and specificity of each tracer. RESULTS: Tl, BMIPP, or MIBG cardiac scintigraphy were useful to diagnose patients with VSA, because sensitivity was 57-73%. Specificity was 55-83%. Sensitivity of left circumflex artery was significantly lower than other vessels. BMIPP imaging may be helpful for clinical course of VSA. However, myocardial scintigraphic abnormal findings may not always show the ischemic memory due to coronary artery spasm. CONCLUSIONS: Recent cardiologists do not perform hyperventilation tests or MIBG scintigraphy for diagnosis of coronary spasm. After understanding the flow of the times, cardiologists should use Tl or BMIPP myocardial scintigraphy for VSA as one of supplementary tools in the real world.
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3-Yodobencilguanidina , Vasoespasmo Coronario/diagnóstico por imagen , Ácidos Grasos , Yodobencenos , Imagen de Perfusión Miocárdica , Radioisótopos de Talio , HumanosRESUMEN
Idiopathic olfactory disorder is resistant to treatment, and the recovery time is long. This study investigated the prognostic value of the migration of nasally administered thallium-201 to the olfactory bulb (thallium migration to the OB), a measure of olfactory nerve damage, in patients with idiopathic olfactory disorders. Twenty-four patients with idiopathic olfactory disorders were enrolled in the study (7 women and 17 men; aged 23-73 years). We retrospectively analyzed potential prognostic markers in subjects who underwent thallium-based olfactory imaging with the nasal administration of thallium-201 before conventional treatment with the Japanese herbal medicine tokishakuyakusan and compared those data with the prognosis. Log-rank tests were performed to assess the relationship between thallium migration to the OB (<4.6% [low] vs. ≥4.6% [high]; data dichotomized at the optimal cutoff value) and the duration until recovery of the odor recognition threshold determined by a standard olfactory function test (T&T olfactometry) after the treatment. Upon statistical analysis, we found that high thallium migration to the OB was significantly correlated with better prognosis in patients. Our results suggest that patients with intact olfactory nerve fibers could be selected using thallium-based imaging for the long-term follow-up of olfactory dysfunction.
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Enfermedades del Nervio Olfatorio/diagnóstico por imagen , Enfermedades del Nervio Olfatorio/patología , Nervio Olfatorio/diagnóstico por imagen , Nervio Olfatorio/patología , Radioisótopos de Talio/administración & dosificación , Administración Intranasal , Adulto , Anciano , Femenino , Humanos , Marcaje Isotópico , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Retrospectivos , Adulto JovenRESUMEN
Radioactivity in the soil of a tea garden in the Fatickchari area in Chittagong, Bangladesh, was measured using a high-resolution HPGe detector. The soil samples were collected from depths of up to 20 cm beneath the soil surface. The activity concentrations of naturally occurring (238)U and (232)Th were observed to be in the range of 27 ± 7 to 53 ± 8 Bq kg(-1) and 36 ± 11 to 72 ± 11 Bq kg(-1), respectively. The activity concentration of (40)K ranged from 201 ± 78 to 672 ± 81 Bq kg(-1), and the highest activity of fallout (137)Cs observed was 10 ± 1 Bq kg(-1). The average activity concentration observed for (238)U was 39 ± 8 Bq kg(-1), for (232)Th was 57 ± 11 Bq kg(-1), for (40)K was 384 ± 79 Bq kg(-1) and for (137)Cs was 5 ± 0.5 Bq kg(-1). The radiological hazard parameters (representative level index, radium equivalent activity, outdoor and indoor dose rates, outdoor and indoor annual effective dose equivalents, and radiation hazard index) were calculated from the radioactivity in the soil.
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Camellia sinensis , Contaminantes Radiactivos del Suelo/análisis , Agricultura , Radiación de Fondo , Bangladesh , Camellia sinensis/crecimiento & desarrollo , Radioisótopos de Cesio/análisis , Humanos , Exposición Profesional , Radioisótopos de Potasio/análisis , Monitoreo de Radiación , Radioisótopos de Talio/análisis , Uranio/análisisRESUMEN
Meningiomas arise from the meningothelial cells of the arachnoid membranes. They are the most common primary intracranial neoplasms and represent about 20% of all intracranial tumors. They are usually diagnosed after the third decade of life and they are more frequent in women than in men. According to the World Health Organization (WHO) criteria, meningiomas can be classified into grade I meningiomas, which are benign, grade II (atypical) and grade III (anaplastic) meningiomas, which have a much more aggressive clinical behaviour. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are routinely used in the diagnostic workup of patients with meningiomas. Molecular Nuclear Medicine Imaging with Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) could provide complementary information to CT and MRI. Various SPECT and PET tracers may provide information about cellular processes and biological characteristics of meningiomas. Therefore, SPECT and PET imaging could be used for the preoperative noninvasive diagnosis and differential diagnosis of meningiomas, prediction of tumor grade and tumor recurrence, response to treatment, target volume delineation for radiation therapy planning, and distinction between residual or recurrent tumour from scar tissue.
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Neoplasias Encefálicas/diagnóstico por imagen , Meningioma/diagnóstico por imagen , Tomografía de Emisión de Positrones/métodos , Tomografía Computarizada de Emisión de Fotón Único/métodos , Ácido Acético , Adulto , Amoníaco , Radioisótopos de Carbono , Colina , Femenino , Fluorodesoxiglucosa F18 , Humanos , Masculino , Meningioma/metabolismo , Radioisótopos de Nitrógeno , Octreótido/análogos & derivados , Compuestos Organometálicos , Radiofármacos , Receptores de Somatostatina/metabolismo , Tecnecio , Radioisótopos de Talio , TirosinaRESUMEN
In this paper, data available on nuclear medicine imaging using commercially available radiopharmaceuticals for the differentiation, staging, and prediction or assessment of the response to treatment in tuberculosis (TB) are reviewed. Limited available studies suggest that single photon emission computed tomography (SPECT) using either 201Tl, 99mTc-sestamibi, or 99mTc-tetrofosmin is accurate (≥85%) and has a high negative predictive value (≥90%) for the differentiation of TB from carcinoma in patients presenting with a solitary pulmonary nodule (SPN). The criteria for detection of TB on 201Tl SPECT are nondepiction of the suspicious lesion in the delayed image or a negative retention index [washout on the delayed images (34 h postinjection) vs. the early image (515 min postinjection)] and a comparable-to-background uptake on 99mTc-sestamibi or 99mTc-tetrofosmin SPECT. Another SPECT tracer of potential interest for the differentiation of TB from malignant SPN that warrants further exploration, is N-isopropyl-p-[123I]iodoamphetamine (123I-IMP). In contrast, 18F-fluorodeoxyglucose (18F-FDG) PET is unable to differentiate malignancy from TB and thus cannot be used as a tool to reduce futile biopsy/thoracotomy in these patients. A limited number of studies have reported on the potential of nuclear medicine imaging in assessment of the extent of disease in patients with extrapulmonary TB using 67Ga-citrate SPECT and 18F-FDG PET, respectively. 67Ga-citrate SPECT was shown to be as sensitive as bone scintigraphy for the detection of bone infection and was found to be complementary to computed tomography (CT) imaging. 18F-FDG PET was found to be significantly more efficient when compared with CT, respectively, in over half of patients for the identification of sites of lymph node involvement that were missed by CT and often the only sites of extrapulmonary TB identified. Unfortunately, 18F-FDG PET findings did not lead to alterations in treatment planning in any of the patients under study. Additional studies confirming these findings are urgently required. Similar to the setting of SPN, 18F-FDG PET cannot differentiate malignant lymph node involvement from lymph node involvement by TB. These results and the recent findings of Demura and colleagues using 18F-FDG PET further suggest that nuclear medicine imaging techniques could be used for the evaluation of therapeutic response. Prospective studies, focusing on specific subgroups of patients in whom such an imaging approach might be clinically relevant, for example in multidrug-resistant TB patients, are warranted. In acquired immunodeficiency syndrome patients, 67Ga scintigraphy proved to be a reliable and sensitive method for the primary detection and follow-up of opportunistic pneumonias, including TB. Combining 201Tl scintigraphy with 67Ga scintigraphy was shown to increase the specificity for both pulmonary and extrapulmonary TB, which is a 67Ga(+) and 201Tl(-) mismatch pattern in acquired immunodeficiency syndrome patients that is specific for mycobacterial infections. Finally, the results obtained using both SPECT and PET indicate that nuclear medicine could be an important noninvasive method for the determination of disease activity, detection of extrapulmonary TB, and determination of response to therapy.
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Medicina Nuclear/métodos , Radiofármacos , Tuberculosis Pulmonar/diagnóstico por imagen , Diagnóstico Diferencial , Fluorodesoxiglucosa F18 , Radioisótopos de Galio , Humanos , Yofetamina , Neoplasias Pulmonares/diagnóstico por imagen , Imagen por Resonancia Magnética , Compuestos Organofosforados , Compuestos de Organotecnecio , Tomografía de Emisión de Positrones , Pronóstico , Sensibilidad y Especificidad , Tecnecio Tc 99m Sestamibi , Radioisótopos de Talio , Tomografía Computarizada de Emisión de Fotón Único/métodos , Tomografía Computarizada por Rayos X , Tuberculosis Pulmonar/diagnósticoRESUMEN
BACKGROUND: We studied the use of (201)Thallium SPECT and L-[1-(11)C]-tyrosine PET in patients with a primary glioblastoma multiforme treated with (192)Ir brachytherapy after surgery and external beam radiation therapy. We hypothesised that the patients most likely to benefit from further surgery after deterioration would be those with radiation necrosis and would be recognised by a negative emission tomography scan. METHODS: Twenty-one patients underwent (201)Thallium SPECT performed before brachytherapy, and this was repeated in 19 patients when recurrence was suspected. Nine patients also underwent a PET scan at the same time. Nine patients underwent a second operation. FINDINGS: SPECT and PET were highly concordant concerning the prediction of radionecrosis and/or tumour recurrence. Repeat surgery did not lead to a significant increase in survival. There was no significant association between the duration of survival and tumour-to-background ratio but the number studied was small. Both SPECT and PET showed highly active lesions, which were proved to be recurrent tumour by clinical and histological follow-up. CONCLUSION: Although PET and SPECT are both highly sensitive in detecting active tumour tissue, emission tomography was not clinically valuable in the investigation of patients with a primary glioblastoma treated with brachytherapy.
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Braquiterapia , Neoplasias Encefálicas/radioterapia , Irradiación Craneana , Glioblastoma/radioterapia , Radioisótopos de Iridio/uso terapéutico , Recurrencia Local de Neoplasia/diagnóstico por imagen , Complicaciones Posoperatorias/diagnóstico por imagen , Tomografía Computarizada de Emisión de Fotón Único , Adulto , Anciano , Encéfalo/diagnóstico por imagen , Encéfalo/efectos de la radiación , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/cirugía , Radioisótopos de Carbono , Terapia Combinada , Diagnóstico Diferencial , Supervivencia sin Enfermedad , Femenino , Estudios de Seguimiento , Glioblastoma/diagnóstico por imagen , Glioblastoma/mortalidad , Glioblastoma/cirugía , Humanos , Radioisótopos de Iridio/efectos adversos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/cirugía , Tomografía de Emisión de Positrones , Complicaciones Posoperatorias/cirugía , Traumatismos por Radiación/diagnóstico por imagen , Radioterapia Adyuvante , Reoperación , Sensibilidad y Especificidad , Radioisótopos de Talio , TirosinaRESUMEN
A carbon-rich black layer, dating to approximately 12.9 ka, has been previously identified at approximately 50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it. Causes for the extinctions, YD cooling, and termination of Clovis culture have long been controversial. In this paper, we provide evidence for an extraterrestrial (ET) impact event at approximately equal 12.9 ka, which we hypothesize caused abrupt environmental changes that contributed to YD cooling, major ecological reorganization, broad-scale extinctions, and rapid human behavioral shifts at the end of the Clovis Period. Clovis-age sites in North American are overlain by a thin, discrete layer with varying peak abundances of (i) magnetic grains with iridium, (ii) magnetic microspherules, (iii) charcoal, (iv) soot, (v) carbon spherules, (vi) glass-like carbon containing nanodiamonds, and (vii) fullerenes with ET helium, all of which are evidence for an ET impact and associated biomass burning at approximately 12.9 ka. This layer also extends throughout at least 15 Carolina Bays, which are unique, elliptical depressions, oriented to the northwest across the Atlantic Coastal Plain. We propose that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling. The shock wave, thermal pulse, and event-related environmental effects (e.g., extensive biomass burning and food limitations) contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.
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Planeta Tierra , Extinción Biológica , Meteoroides , Animales , Carbono/análisis , Clima , Ecosistema , Fenómenos Geológicos , Geología , Humanos , Hielo/análisis , Iridio/análisis , Magnetismo , Modelos Teóricos , América del Norte , Fenómenos Físicos , Física , Suelo/análisis , Radioisótopos de Talio/análisis , Factores de Tiempo , Uranio/análisisRESUMEN
Not uncommonly, hemodialysis patients with normal results in myocardial perfusion tests can still have a cardiac event within 2 years of evaluation. We examined possible risk factors for progression of coronary atherosclerosis in hemodialysis patients. We prospectively evaluated ability of myocardial perfusion imaging carried out under pharmacologic stress to predict 2-year outcomes in 77 hemodialysis patients, specifically thallium-201 single-photon emission computed tomography (SPECT) using high-dose adenosine triphosphate as the stressor. The primary end-point was a cardiac event (cardiac death, non-fatal acute coronary syndrome, or hospitalization for acute ischemic heart failure). Factors independently influencing duration until a cardiac event in hemodialysis patients were identified using stepwise multiple regression analysis. Myocardial perfusion defects were shown in 36 patients. Patients with a perfusion defect were more likely to have cardiac events than those with normal perfusion (78% vs. 15%, P < 0.001). Time until occurrence of a cardiac event in hemodialysis patients showed a significant, independent association with known coronary artery disease [regression coefficient (RC) = -3.391, P = 0.046], elevated C-reactive protein (RC = -5.813, P = 0.005), and a reversible myocardial perfusion defect (RC = -7.386, P < 0.001). An analysis based on the 'best cut-off' of CRP as identified on the basis of the ROC curve augmented the positive and negative predict value of CRP for the prediction of coronary events to 65 and 74%, respectively. Myocardial perfusion SPECT and measuring the plasma concentration of CRP might be useful for the prediction of hemodialysis patients with progression of coronary atherosclerosis.
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Enfermedad de la Arteria Coronaria/diagnóstico , Enfermedad de la Arteria Coronaria/etiología , Diálisis Renal , Adenosina Trifosfato/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Ecocardiografía , Femenino , Corazón/diagnóstico por imagen , Corazón/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Curva ROC , Insuficiencia Renal/complicaciones , Insuficiencia Renal/terapia , Factores de Riesgo , Radioisótopos de Talio , Tomografía Computarizada de Emisión de Fotón ÚnicoRESUMEN
Cardiovascular disease is the most frequent cause of death and disability in diabetes, and the morbidity and mortality for coronary artery disease (CAD) in this population is two to four times higher than in nondiabetic subjects. Traditional risk factors do not fully explain the level of cardiovascular risk, and coronary disease events are often silent in diabetic patients. Thus, research has recently focused on improving the risk assessment of an individual patient with new tools in an effort to better identify subjects at highest risk and in need of aggressive management. Cardiovascular imaging has proven very helpful in this regard. Traditional methods to assess CAD are based on detection of obstructive luminal disease responsible for myocardial ischemia. However, acute coronary syndromes often occur in the absence of luminal stenoses. Hence, the utilization of imaging methodologies to visualize atherosclerosis in its presymptomatic stages has received mounting attention in recent years. In this article, we review the current literature on the utility of traditional imaging modalities for obstructive CAD (nuclear and echocardiographic stress testing) as well as atherosclerosis plaque imaging with carotid intima-media thickness and coronary artery calcium for risk stratification of diabetic patients.
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Enfermedades Cardiovasculares/etiología , Enfermedad de la Arteria Coronaria/diagnóstico , Complicaciones de la Diabetes , Isquemia Miocárdica/diagnóstico por imagen , Gestión de Riesgos , Enfermedades Cardiovasculares/epidemiología , Enfermedad de la Arteria Coronaria/complicaciones , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/patología , Diabetes Mellitus , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 2/complicaciones , Ecocardiografía de Estrés , Humanos , Angiografía por Resonancia Magnética , Compuestos Organofosforados , Compuestos de Organotecnecio , Radiografía , Tecnecio Tc 99m Sestamibi , Radioisótopos de Talio , Tomografía Computarizada de Emisión de Fotón Único , Túnica Íntima/patología , Túnica Media/patologíaRESUMEN
Radionuclide levels in vegetation from a High Arctic location were studied and compared to in situ soil concentrations. Levels of the anthropogenic radionuclide 137Cs and the natural radionuclides 40K, 238U, 226Ra and 232Th are discussed and transfer factor (TF) values and aggregated transfer (Tag) values are calculated for vascular plants. Levels of 137Cs in vegetation generally followed the order mosses > lichen > vascular plants. The uptake of 137Cs in vascular plants showed an inverse relationship with the uptake of 40K, with 137Cs TF and Tag values generally higher than 40K TF and Tag values. 40K activity concentrations in all vegetation showed little correlation to associated soil concentrations, while the uptake of 238U, 226Ra and 232Th by vascular and non-vascular plants was generally low.
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Plantas/metabolismo , Radioisótopos/farmacocinética , Contaminantes Radiactivos del Aire/farmacocinética , Regiones Árticas , Briófitas/metabolismo , Radioisótopos de Cesio/farmacocinética , Exposición a Riesgos Ambientales/efectos adversos , Líquenes/metabolismo , Magnoliopsida/metabolismo , Radioisótopos de Potasio/farmacocinética , Radón/farmacocinética , Suelo/análisis , Contaminantes Radiactivos del Suelo/análisis , Radioisótopos de Talio/farmacocinética , Uranio/farmacocinéticaRESUMEN
STATEMENT OF PROBLEM: Microleakage between resilient liner and denture base resins is a significant clinical problem, often responsible for debonding of the resilient liner from the denture base resin. PURPOSE: This study investigated the effect of 2 surface treatments, airborne-particle abrasion (APA) and wetting with methyl methacrylate monomer (MMA), on microleakage between a silicone-based resilient liner and denture base resin using a gamma camera imaging technique. MATERIAL AND METHODS: Thirty-three specimens, each having 2 plates measuring 40 x 40 x 2 mm, were prepared by packing and processing an acrylic denture base resin (QC-20) into square plates following manufacturer's instructions. Specimens were divided into 3 groups (n=11) as APA-, MMA-, and control-treatment groups. For the APA group, the inner surfaces of both plates were airborne-particle abraded with 250-microm Al 2 O 3 particles and, for the MMA group, surfaces were treated with monomer (QC-20). Control specimens were not surface treated. Following application of an adhesive (Ufi Gel P-specific), a silicone lining material (Ufi Gel P) was prepared and applied to the inner surfaces of all 33 specimens. Eleven size-matched polymethyl methacrylate (PMMA) specimen blocks (40 x 40 x 6 mm) were prepared to calculate the level of residual radioactivity for the denture base itself, the entire outer surface count (OSC). All specimens and PMMA blocks were immersed in a radioactive solution (thallium-201 chloride) for 24 hours. Specimen activities (gamma-ray cts/sec, representing thallium-201 concentration) were then measured using a high-resolution gamma camera. The amount of OSC-subtracted total specimen counts was a direct indicator of the quantity of inward diffusing tracer. The subtracted values were analyzed using a 1-way analysis of variance (ANOVA) and Bonferroni multiple comparison tests (alpha=.05). RESULTS: OSC levels averaged 754 +/- 110 gamma-ray cts/sec. OSC-subtracted APA, control, and MMA values were 5,546 +/- 1,534, 3,392 +/- 738, and 1,405 +/- 392 gamma-ray cts/sec, respectively. All 3 groups were significantly different ( P <.05) from each other. Surface wetting with MMA showed the lowest microleakage values among all specimen groups. CONCLUSION: In terms of microleakage, surface treatment with MMA monomer preceding the adhesive application demonstrated lower values than adhesive application alone. APA pretreatment resulted in 4 times the microleakage found in MMA-treated specimens, and 1.5 times the microleakage of the untreated control. None of the surface pretreatments completely prevented microleakage. Microleakage between the silicone-based resilient liner and denture base resin can be quantitatively determined using the gamma camera imaging technique.
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Resinas Acrílicas/química , Filtración Dental/clasificación , Bases para Dentadura , Alineadores Dentales , Elastómeros de Silicona/química , Abrasión Dental por Aire , Óxido de Aluminio/química , Análisis de Varianza , Difusión , Cámaras gamma , Humanos , Metilmetacrilato/química , Polimetil Metacrilato/química , Radiofármacos/química , Propiedades de Superficie , Radioisótopos de Talio/químicaRESUMEN
In a patient receiving 5-fluorouracil and levamisole, neurologic deficits suggest the cerebral demyelinating syndrome as a differential diagnosis. The authors report a patient diagnosed as multifocal inflammatory leukoencephalopathy for which thallium-201 (201Tl) single photon emission computed tomography (SPECT) and proton magnetic resonance spectroscopy (MRS) were employed as noninvasive diagnostic tools. 201Tl SPECT study was negative and proton MRS showed an increase of choline and lactate and well preserved N-acetylaspartate. These findings support histopathologic findings of multifocal inflammatory leukoencephalopathy revealing demyelination with relative axonal sparing in the patient.
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Ácido Aspártico/análogos & derivados , Leucoencefalopatía Multifocal Progresiva/diagnóstico , Espectroscopía de Resonancia Magnética/métodos , Radioisótopos de Talio , Tomografía Computarizada de Emisión de Fotón Único/métodos , Adyuvantes Inmunológicos/efectos adversos , Adyuvantes Inmunológicos/uso terapéutico , Antimetabolitos Antineoplásicos/efectos adversos , Antimetabolitos Antineoplásicos/uso terapéutico , Ácido Aspártico/metabolismo , Axones/patología , Biopsia , Encéfalo/patología , Neoplasias Encefálicas/secundario , Colina/metabolismo , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Diagnóstico Diferencial , Fluorouracilo/efectos adversos , Fluorouracilo/uso terapéutico , Humanos , Ácido Láctico/metabolismo , Leucoencefalopatía Multifocal Progresiva/etiología , Levamisol/efectos adversos , Levamisol/uso terapéutico , Masculino , Persona de Mediana Edad , Metástasis de la NeoplasiaRESUMEN
AIM: Differentiated thyroid cancer is characterized by a very good prognosis in the majority of the patients. The therapy of choice is surgery followed by ablation with Iodine-131 (I-131). However, some patients have metastases that have lost the capability of concentrating I-131, even when it is given in therapeutic doses. In the present study, we describe the value of Indium-111 Octreotide (Octreoscan) in differentiated thyroid cancer patients with increased Tg levels who failed to demonstrate a response to treatment with high-dose I-131. METHOD: Fifteen consecutive patients with progressive differentiated thyroid cancer (ten female, five male) (mean age: 59 years, range 13-81 years; eight papillary, six follicular, and one Hürthle cell carcinoma) were studied. Progression was based on increasing Tg levels and was confirmed by radiological evaluation. Whole body scintigraphy (WBS) was performed after the administration of 200 MBq of Indium-111-Octreotide. The images were assessed by two experienced observers and compared with post-treatment I-131 WBS. RESULTS: In seven out of 15 patients distant metastases were already present at initial stage, whereas in ten patients the primary tumor stage was T3 or T4 indicating that the majority of the patients had advanced disease. In two out of five patients with a positive I-131 WBS, Indium-111-Octreotide was false negative. In nine out of ten patients with a negative I-131 WBS, Indium-111-Octreotide demonstrated multiple metastases. In those patients with a positive SSR-scintigraphy, metastases were found in the lungs ( n=14), bone ( n=7), mediastinum ( n=3), liver ( n=2), brains ( n=1), and cutis ( n=1). Overall, three out of 15 patients had a negative Indium-111-Octreotide result revealing a sensitivity of 80%. CONCLUSION: Our findings demonstrate the diagnostic value of Indium-111-Octreotide in differentiated thyroid cancer that fails to respond to I-131 treatment. It opens the possibility for additional treatment with high doses of Indium-111-Octreotide or its analogs in a majority of the patients.
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Antineoplásicos Hormonales , Carcinoma Papilar/diagnóstico por imagen , Radioisótopos de Indio , Radioisótopos de Yodo/uso terapéutico , Octreótido , Radiofármacos , Receptores de Somatostatina/análisis , Neoplasias de la Tiroides/diagnóstico por imagen , Tomografía Computarizada de Emisión , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma Papilar/química , Carcinoma Papilar/radioterapia , Progresión de la Enfermedad , Femenino , Fluorodesoxiglucosa F18 , Humanos , Masculino , Persona de Mediana Edad , Somatostatina/análogos & derivados , Somatostatina/uso terapéutico , Tecnecio Tc 99m Sestamibi , Radioisótopos de Talio , Neoplasias de la Tiroides/química , Neoplasias de la Tiroides/radioterapia , Tomografía Computarizada de Emisión/métodos , Insuficiencia del TratamientoRESUMEN
In a patient receiving 5-fluorouracil and levamisole, neurologic deficits suggest the cerebral demyelinating syndrome as a differential diagnosis. The authors report a patient diagnosed as multifocal inflammatory leukoencephalopathy for which thallium-201 ((201)Tl) single photon emission computed tomography (SPECT) and proton magnetic resonance spectroscopy (MRS) were employed as noninvasive diagnostic tools. (201)Tl SPECT study was negative and proton MRS showed an increase of choline and lactate and well preserved N-acetylaspartate. These findings support histopathologic findings of multifocal inflammatory leukoencephalopathy revealing demyelination with relative axonal sparing in the patient.
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Humanos , Masculino , Persona de Mediana Edad , Adyuvantes Inmunológicos/efectos adversos , Antimetabolitos Antineoplásicos/efectos adversos , Ácido Aspártico/análogos & derivados , Axones/patología , Biopsia , Encéfalo/patología , Neoplasias Encefálicas/secundario , Colina/metabolismo , Neoplasias Colorrectales/tratamiento farmacológico , Diagnóstico Diferencial , Fluorouracilo/efectos adversos , Ácido Láctico/metabolismo , Leucoencefalopatía Multifocal Progresiva/diagnóstico , Levamisol/efectos adversos , Espectroscopía de Resonancia Magnética/métodos , Metástasis de la Neoplasia , Radioisótopos de Talio , Tomografía Computarizada de Emisión de Fotón Único/métodosRESUMEN
BACKGROUND: The aim of this prospective study was to investigate the concordance between quantitative resting (201)Tl uptake as an established myocardial viability index and the electrical activity of the heart, determined by NOGA nonfluoroscopic electroanatomic mapping. METHODS AND RESULTS: The myocardial resting and late resting thallium uptakes of 384 myocardial segments from 32 patients (27 males aged 65+/-8 years) with previous myocardial infarction and chronic stable angina were compared with unipolar voltage potentials and local shortening of the left ventricle as assessed by electroanatomic mapping. The quantitative thallium uptake data were analyzed by polar map analysis by division into 12 comparable myocardial segments, as represented in electroanatomic mapping images. Unipolar voltage potentials exhibited a significant logarithmic correlation with both resting and late resting thallium uptake (attenuation corrected: r=0.660 and r=0.744; non-attenuation corrected: r=0.623 and r=0.721). Receiver operator characteristic analyses revealed unipolar voltage cutoff points of 12.0 mV (predictive accuracy 0.853, P< 0.001; sensitivity/specificity 81%) for normal myocardium and 6.4 mV (predictive accuracy 0.901, P< 0.001; sensitivity/specificity 82%) for nonviable myocardium assessed by attenuation-corrected (201)Tl late resting images and of 12.7 mV (predictive accuracy 0.822, P<0.001; sensitivity/specificity 75%) and 6.5 mV (predictive accuracy 0.808, P<0.001; sensitivity/specificity 73%) for non-attenuation-corrected late resting (201)Tl images. CONCLUSIONS: These results indicate that the unipolar voltage potentials obtained by electroanatomic mapping correlate well with standard quantitative late resting (201)Tl imaging for the evaluation of myocardial viability; thus, NOGA endocardial mapping provides useful "online" data at the time of catheterization, especially when information from other methods for viability assessment is unavailable.
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Cateterismo Cardíaco , Técnicas Electrofisiológicas Cardíacas/métodos , Corazón/diagnóstico por imagen , Adulto , Endocardio/diagnóstico por imagen , Endocardio/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Cintigrafía , Radioisótopos de TalioRESUMEN
UNLABELLED: There are several reports about the usefulness of (18)F-FDG PET in thyroid cancer. However, few studies have compared FDG PET with (131)I and (201)Tl scintigraphy. The aim of this study was to evaluate the clinical significance of whole-body FDG PET in differentiated thyroid cancer and to compare the results with those obtained from (131)I and (201)Tl scintigraphy. METHODS: Whole-body FDG PET was performed on 32 patients (10 men, 22 women; age range, 30-77 y; mean age, 54 y) with differentiated thyroid cancer (5 cases of follicular cancer and 27 of papillary cancer) after total thyroidectomy. An overall clinical evaluation was performed, including cytology, thyroglobulin level, sonography, MRI, and CT, to allow a comparison with functional imaging results for each patient. Metastatic regions were divided into five areas: neck, lung, mediastinum, bone, and other. Multiple lesions in one area were defined as one lesion. The tumor-to-background ratio (TBR) was measured for the lesions that were positive for both (201)Tl uptake and FDG PET uptake. RESULTS: The number of lesions totaled 47. Forty-one (87%) were detected by all scintigraphic methods. FDG uptake was concordant with (131)I uptake in only 18 lesions (38%). FDG uptake was concordant with (201)Tl uptake in 44 lesions (94%). Only one lesion was negative for FDG uptake and positive for (201)Tl uptake, and two lesions were positive for FDG uptake and negative for (201)Tl uptake. A significant correlation was seen between the TBR of (201)Tl and that of FDG (r = 0.69; P<0.05). CONCLUSION: These data indicate that for detecting metastatic lesions, FDG PET and (131)I scintigraphy may provide complementary information, whereas FDG PET may provide results similar to those of (201)Tl scintigraphy. Thus, the combination of (131)I scintigraphy and FDG PET (or (201)Tl scintigraphy) is the method of choice for detecting metastatic thyroid cancer after total thyroidectomy.
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Adenocarcinoma Folicular/diagnóstico por imagen , Adenocarcinoma Folicular/secundario , Carcinoma Papilar/diagnóstico por imagen , Carcinoma Papilar/secundario , Fluorodesoxiglucosa F18 , Radioisótopos de Yodo , Recurrencia Local de Neoplasia/diagnóstico por imagen , Radiofármacos , Radioisótopos de Talio , Neoplasias de la Tiroides/diagnóstico por imagen , Tomografía Computarizada de Emisión , Adulto , Anciano , Neoplasias Óseas/diagnóstico por imagen , Neoplasias Óseas/secundario , Femenino , Neoplasias de Cabeza y Cuello/diagnóstico por imagen , Neoplasias de Cabeza y Cuello/secundario , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/secundario , Metástasis Linfática/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Neoplasias de la Tiroides/patologíaRESUMEN
OBJECTIVE: To test the hypothesis that syndrome X is a systemic vascular disorder, the authors studied 40 patients with this diagnosis using technetium-99m hexamethylpropylene amine oxime and single photon emission computed tomography (SPECT) brain images. Twenty-three of 25 cases with definite myocardial perfusion defects diagnosed by thallium-201 myocardial perfusion SPECT also had multiple hypoperfusion areas in the brain versus 2 of 15 patients without thallium myocardial defects. The parietal lobes were the most common hypoperfusion areas, and cerebellum was the least common. Syndrome X is a systemic vascular disorder with a high incidence of hypoperfusion lesions of the brain and is usually coincident with myocardial defects.
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Isquemia Encefálica/diagnóstico por imagen , Encéfalo/irrigación sanguínea , Angina Microvascular/diagnóstico por imagen , Tomografía Computarizada de Emisión de Fotón Único , Adulto , Ganglios Basales/irrigación sanguínea , Isquemia Encefálica/fisiopatología , Cerebelo/irrigación sanguínea , Corteza Cerebral/irrigación sanguínea , Femenino , Humanos , Masculino , Angina Microvascular/fisiopatología , Persona de Mediana Edad , Flujo Sanguíneo Regional/fisiología , Exametazima de Tecnecio Tc 99m , Tálamo/irrigación sanguínea , Radioisótopos de TalioRESUMEN
The objective of this study was to examine the feasibility of an accurate in situ measurement of radioactive hot spots by a HPGe detector located at a height of 0.1 m above the surface, thus sparing the awkward use of a heavy collimator required at the standard 1 m height. Radioactivity concentrations of primordial naturally occurring 40K, 232Th, 238U and of anthropogenic 137Cs in a sand plot were measured in situ at the two heights. Independently, six fractions of a soil profile collected in the site were measured in the laboratory. Good agreement was found between the results of the two geometries and the soil samples. Good agreement between measured and predicted radioactivity concentration values was obtained for hot spots simulated by uniform planar sources of 40K, 60Co and 137Cs having a circular pattern 0.5 m in diameter. The study shows that an in situ measurement without a collimator but close to a hot spot can provide a reliable result.
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Radioisótopos de Cesio/análisis , Radioisótopos de Potasio/análisis , Monitoreo de Radiación/instrumentación , Monitoreo de Radiación/métodos , Radioisótopos de Talio/análisis , Uranio/análisis , Calibración , Rayos gamma , Reproducibilidad de los Resultados , Contaminantes Radiactivos del Suelo/análisisRESUMEN
Radioiodine treatment following surgery is an effective therapy in differentiated thyroid carcinoma (DTC) patients. However, in DTC patients with metastases characterized by very low or absent iodine uptake, total thyroidectomy and radical loco-regional lymphoadenectomy is the only effective therapeutic approach. In the present article, we have discussed the most recently available nuclear medicine techniques utilized for the detection of DTC metastases that have lost the capacity to trap radioiodine. A review of the data published in the literature has been presented, and a comparative analysis made of the results obtained by other imaging modalities such as high resolution neck ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). In our experience, the most sensitive and accurate imaging procedure is represented by the combination of neck US and whole body 99mTc-methoxy-isobutylisonitrile (99mTc-MIBI) scintigraphy; this combination might be proposed as a first-line diagnostic approach in DTC patients with increased serum thyroglobulin (Tg) levels and negative high dose 131I scans.