RESUMEN
INTRODUCTION: It has been reported that the survival of patients having sentinel node (SN) biopsy for melanoma the day after lymphoscintigraphy using Tc99m-nanocolloid is worse than that of patients having lymphoscintigraphy and SN biopsy on the same day [1,2]. A possible explanation suggested is that overnight migration of the tracer from SNs to 2nd-tier nodes occurs, causing failure to remove true SNs. MATERIALS AND METHODS: The possibility of overnight tracer migration leading to errors in SN-identification was investigated in 12 patients scheduled for lymphoscintigraphy the day before surgery by repeating SPECT-CT imaging the next morning, before their SN biopsy. The aim was to check whether onward migration of colloid from previously-identified SNs had occurred. RESULTS: No significant migration of Tc99m-nanocolloid occurred overnight in any patient. All nodes reported to be SNs on day 1 imaging were also present and regarded as SNs on day 2 images. No new foci were visualised on day 2, but some that had been identified on day 1 were not seen on day 2. CONCLUSIONS: Since migration of nanocolloid overnight did not occur, this cannot explain the reported survival disadvantage for patients undergoing SN biopsy the day after lymphoscintigraphy. A likely alternative possibility is that inadequate doses of radioisotope were used for next-day procedures, causing the mistaken removal of 2nd-tier nodes instead of true SNs more frequently. Further research is required to explain the reported reduction in survival of patients having next-day SN biopsy procedures, since the possibility has important clinical implications.
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Melanoma/secundario , Radiofármacos/farmacocinética , Ganglio Linfático Centinela/diagnóstico por imagen , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Humanos , Metástasis Linfática , Linfocintigrafia , Trazadores Radiactivos , Ganglio Linfático Centinela/patología , Biopsia del Ganglio Linfático Centinela , Tomografía Computarizada por Tomografía Computarizada de Emisión de Fotón Único , Tasa de Supervivencia , Factores de TiempoRESUMEN
The work considers the problem of obtaining nanocolloid radiopharmaceuticals (RPs) and studying their functional suitability for diagnosing sentinel lymph nodes (SLN) in cancer patients. Two principal approaches to the formation of technetium-99m-labeled particles based on inorganic and organic matrices were considered when carrying out research to develop methods for the production of nanocolloid RPs. The composition of the reagents and the conditions for obtaining nanocolloid radiopharmaceuticals were determined. The functional suitability of new RPs for scintigraphic diagnostics of sentinel lymph nodes has been studied.
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Linfocintigrafia/métodos , Radiofármacos/farmacocinética , Ganglio Linfático Centinela/metabolismo , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Animales , Masculino , Ratas , Ratas Wistar , Distribución TisularRESUMEN
BACKGROUND: Hepatopulmonary syndrome (HPS) is an arterial oxygenation defect induced by intrapulmonary vascular dilatation (IPVD) in the setting of liver disease and/or portal hypertension. This syndrome occurs most often in cirrhotic patients (4%-32%) and has been shown to be detrimental to functional status, quality of life, and survival. The diagnosis of HPS in the setting of liver disease and/or portal hypertension requires the demonstration of IPVD (i.e., diffuse or localized abnormally dilated pulmonary capillaries and pulmonary and pleural arteriovenous communications) and arterial oxygenation defects, preferably by contrast-enhanced echocardiography and measurement of the alveolar-arterial oxygen gradient, respectively. AIM: To compare brain and whole-body uptake of technetium for diagnosing HPS. METHODS: Sixty-nine patients with chronic liver disease and/or portal hypertension were prospectively included. Brain uptake and whole-body uptake were calculated using the geometric mean of technetium counts in the brain and lungs and in the entire body and lungs, respectively. RESULTS: Thirty-two (46%) patients had IPVD as detected by contrast-enhanced echocardiography. The demographics and clinical characteristics of the patients with and without IPVD were not significantly different with the exception of the creatinine level (0.71 ± 0.18 mg/dL vs 0.83 ± 0.23 mg/dL; P = 0.041), alveolar-arterial oxygen gradient (23.2 ± 13.3 mmHg vs 16.4 ± 14.1 mmHg; P = 0.043), and arterial partial pressure of oxygen (81.0 ± 12.1 mmHg vs 90.1 ± 12.8 mmHg; P = 0.004). Whole-body uptake was significantly higher in patients with IPVD than in patients without IPVD (48.0% ± 6.1% vs 40.1% ± 8.1%; P = 0.001). The area under the curve of whole-body uptake for detecting IPVD was significantly higher than that of brain uptake (0.75 vs 0.54; P = 0.025). The optimal cut-off values of brain uptake and whole-body uptake for detecting IPVD were 5.7% and 42.5%, respectively, based on Youden's index. The sensitivity, specificity, and accuracy of brain uptake > 5.7% and whole-body uptake > 42.5% for detecting IPVD were 23%, 89%, and 59% and 100%, 52%, and 74%, respectively. CONCLUSION: Whole-body uptake is superior to brain uptake for diagnosing HPS.
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Síndrome Hepatopulmonar/diagnóstico , Imagen de Perfusión/métodos , Cintigrafía/métodos , Radiofármacos/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Adulto , Análisis de los Gases de la Sangre , Encéfalo/irrigación sanguínea , Encéfalo/metabolismo , Dilatación Patológica/diagnóstico , Femenino , Síndrome Hepatopulmonar/etiología , Humanos , Hipertensión Pulmonar/complicaciones , Hepatopatías/complicaciones , Pulmón/irrigación sanguínea , Pulmón/metabolismo , Masculino , Persona de Mediana Edad , Oxígeno/sangre , Estudios Prospectivos , Enfermedades Vasculares/diagnóstico , Enfermedades Vasculares/etiologíaRESUMEN
Preclinical in vivo tests of retinal drug responses are carried out in mice and rats, often after intravitreal injections. However, quantitative pharmacokinetics in the mouse eye is poorly understood. Ocular pharmacokinetics studies are usually done in rabbits. We investigated elimination of three compounds ([99mTc]Tc-pentetate, [111In]In-pentetreotide, [99mTc]Tc-human serum albumin with molecular weights of 510.2 Da, 1506.4 Da, and 66.5 kDa, respectively) from mouse vitreous using imaging with single photon emission computed tomography/computed tomography (SPECT/CT). Increasing molecular weight decreased elimination of the compounds from the mouse eyes. Half-lives of [99mTc]Tc-pentetate, [111In]In-pentetreotide, and [99mTc]Tc-human serum albumin in the mouse eyes were 1.8 ± 0.5 h, 4.3 ± 1.7 h, and 30.0 ± 9.0 h, respectively. These values are 3-12-fold shorter than half-lives of similar compounds in the rabbit vitreous. Dose scaling factors were calculated for mouse-to-rabbit and mouse-to-man translation. They were 27-90 and 38-126, respectively, for intravitreal injections in rabbit and man. We show ocular pharmacokinetic parameters for mice and interspecies scaling factors that may augment ocular drug discovery and development.
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Ojo/diagnóstico por imagen , Ojo/metabolismo , Radiofármacos/metabolismo , Somatostatina/análogos & derivados , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinética , Animales , Humanos , Radioisótopos de Indio/farmacocinética , Inyecciones Intravítreas , Masculino , Ratones , Ratones Endogámicos C57BL , Conejos , Cintigrafía/métodos , Radiofármacos/administración & dosificación , Ratas , Somatostatina/farmacocinética , Distribución TisularRESUMEN
A 30-year-old woman with a recent episode of dyspnea was presented. The lung perfusion scan using Tc-MAA (macro-aggregated albumin) initially revealed an acceptable lung-to-background activity ratio implying a proper radiopharmaceutical preparation and radiolabeling efficiency. Unexpectedly, later during the scan, rapidly increasing concentration of activity was observed in salivary glands, thyroid and stomach. Rapid breakdown of Tc-MAA complexes was considered as a likely explanation for the increase in the circulatory level of the free pertechnetate.
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Pulmón/diagnóstico por imagen , Radiofármacos/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Gammagrafía de Ventilacion-Perfusión , Adulto , Femenino , Humanos , Glándulas Salivales/diagnóstico por imagen , Estómago/diagnóstico por imagen , Glándula Tiroides/diagnóstico por imagenRESUMEN
Tc-99m-galactosyl human serum albumin (GSA) scintigraphy is used to assess the hepatic functional reserve, and allows for visual assessment of the residual hepatocyte distribution on single-photon emission computed tomography/computed tomography (SPECT/CT) images. The association between heterogeneous liver uptake of Tc-99m-GSA and liver fibrosis remains to be studied in detail. We analyzed this association.Fifty-one patients with chronic hepatobiliary disease undergoing a Tc-99m-GSA scintigraphy were included in this study. The receptor (LHL15) and blood clearance (HH15) indexes (the uptake ratios of the liver and heart) were obtained from dynamic planar images. The liver uptake count maximum-to-mean ratio (LUC Max/Mean) was calculated from single-photon emission computed tomography/computed tomography (SPECT/CT) images as an indicator of the Tc-99m-GSA liver uptake heterogeneity. We assessed the relationship between these quantified values and liver fibrosis.There were 30 Child-Pugh classification grade A patients, 16 grade B patients, and 5 grade C patients. Among the 30 patients whose liver histopathology was evaluable, those with advanced liver fibrosis (F2-4) had a lower LHL15 than those with mild liver fibrosis (F0-1) (median, 0.90 vs. 0.92, Pâ=â.04), and a higher LUC Max/Mean (median, 1.80 vs. 1.70, Pâ=â.02). The multivariate analysis identified platelets (Pâ=â.04) and the LUC Max/Mean (Pâ=â.04) as contributing factors of advanced liver fibrosis.These findings suggest that Tc-99m-GSA SPECT/CT can be used not only to assess the hepatic functional reserve, but also to evaluate a degree of liver fibrosis.
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Enfermedades de los Conductos Biliares/complicaciones , Enfermedades de los Conductos Biliares/diagnóstico por imagen , Cirrosis Hepática/diagnóstico por imagen , Cirrosis Hepática/etiología , Radiofármacos/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinética , Anciano , Enfermedad Crónica , Femenino , Hepatocitos , Humanos , Hígado/diagnóstico por imagen , Hígado/patología , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Tomografía Computarizada de Emisión de Fotón ÚnicoRESUMEN
PURPOSE: Sentinel lymph node biopsy (SLNB) can be used for nodal staging in early cervical cancer. For this purpose, the tracers most commonly used are radiotracers based on technetium. For the last decade, indocyanine green (ICG) has been used as a tracer for SLNB in other malignancies with excellent results and, more recently, a combination of ICG and a radiotracer has been shown to have the advantages of both tracers. The aim of this study was to evaluate the role of ICG-99mTc-nanocolloid in SLN detection in patients with cervical cancer. METHODS: This prospective study included 16 patients with cervical cancer. The hybrid tracer was injected the day (19-21 h) before surgery for planar and SPECT/CT lymphoscintigraphy. Blue dye was administered periorificially in 14 patients. SLNs were removed according to their distribution on lymphoscintigraphy and when radioactive, fluorescent and/or stained with blue dye. Nodal specimens were pathologically analysed for metastases including by immunochemistry. RESULTS: Lymphoscintigraphy and SPECT/CT showed drainage in all patients. A total of 69 SLNs were removed, of which 66 were detected by their radioactivity signal and 67 by their fluorescence signal. Blue dye identified only 35 SLNs in 12 of the 14 patients (85.7%). All patients showed bilateral pelvic drainage. Micrometastases were diagnosed in two patients, and were the only lymphatic nodes involved. CONCLUSIONS: SLNB with ICG-99mTc-nanocolloid is feasible and safe in patients with early cervical cancer. This hybrid tracer provided bilateral SLN detection in all patients and a higher detection rate than blue dye, so it could become an alternative to the combined technique.
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Carcinoma de Células Escamosas/diagnóstico por imagen , Verde de Indocianina/farmacocinética , Linfocintigrafia/métodos , Radiofármacos/farmacocinética , Ganglio Linfático Centinela/diagnóstico por imagen , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Neoplasias del Cuello Uterino/diagnóstico por imagen , Adulto , Carcinoma de Células Escamosas/patología , Femenino , Humanos , Verde de Indocianina/administración & dosificación , Linfocintigrafia/normas , Persona de Mediana Edad , Proyectos Piloto , Radiofármacos/administración & dosificación , Agregado de Albúmina Marcado con Tecnecio Tc 99m/administración & dosificación , Tomografía Computarizada de Emisión de Fotón Único/métodos , Tomografía Computarizada de Emisión de Fotón Único/normas , Neoplasias del Cuello Uterino/patologíaRESUMEN
PURPOSE: To evaluate whether technetium-99 (99mTc)-labeled macroaggregated albumin (MAA) can predict subsequent yttrium-90 (90Y) distribution and imaging response in patients with hepatocellular carcinoma (HCC). MATERIALS: Retrospective review was performed of records of 83 patients with HCC who underwent 90Y glass microsphere radioembolization with 99mTc-MAA single photon emission computed tomography (SPECT) and 90Y positron emission tomography (PET)/CT between January 2013 and December 2014. Images were fused to segment the whole liver normal tissue (WLNT) and the largest tumors. Fused images were reviewed and analyzed for comparison of absorbed dose (AD) to tumors and WLNT as calculated from 99mTc-MAA SPECT and from 90Y PET/CT, subjective imaging comparison of 99mTc-MAA SPECT and 90Y PET for tumors and WLNT, and correlation of tumoral AD with response on follow-up CT. RESULTS: Final analysis included 73 and 63 patients for WLNT and tumor 99mTc-MAA/90Y correlation, respectively, and 62 patients for AD vs response. 99mTc-MAA/90Y limit of agreement for each reviewer was viewed as clinically acceptable only for WLNT (-15 to 15 Gy). AD interreviewer variability was clinically acceptable for WLNT but was too broad for tumor. Mean tumor AD for objective response (78%) was 313 Gy vs 234 Gy for nonresponders. No threshold was found between tumor AD and response (P > .1). Catheter mismatch between 99mTc-MAA and 90Y had a direct impact on AD mismatch between the 2 image sets. CONCLUSIONS: 99mTc-MAA was found to be a poor surrogate to quantitatively predict subsequent 90Y AD to hepatocellular tumors. 99mTc-MAA distribution correlated with 90Y distribution in the normal hepatic parenchyma.
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Carcinoma Hepatocelular/diagnóstico por imagen , Neoplasias Hepáticas/diagnóstico por imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones , Radiofármacos/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Tomografía Computarizada de Emisión de Fotón Único , Radioisótopos de Itrio/farmacocinética , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Microesferas , Persona de Mediana Edad , Estudios Retrospectivos , Distribución TisularRESUMEN
Peritoneal radionuclide scan is an established imaging modality for evaluating peritoneopleural communications. In this case report, unusual mediastinal lymph node radiotracer uptake is seen in a patient with portal hypertension on peritoneal scintigraphy. This was suspected to be due to marked lymphatic enlargement from longstanding portal hypertension since childhood, permitting passage of the large Tc-99m MAA particle. The nodes were morphologically benign on CT. Mediastinal lymph node uptake on peritoneal scintigraphy is rare but should not raise undue clinical concern, particularly in a patient with chronic portal hypertension. Anatomic correlation with SPECT-CT can provide reassurance.
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Hipertensión Portal/complicaciones , Ganglios Linfáticos/diagnóstico por imagen , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Fístula , Humanos , Cintigrafía , Radiofármacos , Albúmina Sérica Humana , TecnecioRESUMEN
UNLABELLED: Our goal is to develop minimally invasive biomarkers for predicting radiation-induced lung injury before symptoms develop. Currently, there are no biomarkers that can predict radiation pneumonitis. Radiation damage to the whole lung is a serious risk in nuclear accidents or in radiologic terrorism. Our previous studies have shown that a single dose of 15 Gy of x-rays to the thorax causes severe pneumonitis in rats by 6-8 wk. We have also developed a mitigator for radiation pneumonitis and fibrosis that can be started as late as 5 wk after radiation. METHODS: We used 2 functional SPECT probes in vivo in irradiated rat lungs. Regional pulmonary perfusion was measured by injection of (99m)Tc-macroaggregated albumin. Perfused volume was determined by comparing the volume of distribution of (99m)Tc-macroaggregated albumin to the anatomic lung volume obtained by small-animal CT. A second probe, (99m)Tc-labeled Duramycin, which binds to apoptotic cells, was used to measure pulmonary cell death in the same rat model. RESULTS: The perfused volume of lung was decreased by about 25% at 1, 2, and 3 wk after receipt of 15 Gy, and (99m)Tc-Duramycin uptake was more than doubled at 2 and 3 wk. There was no change in body weight, breathing rate, or lung histology between irradiated and nonirradiated rats at these times. Pulmonary vascular resistance and vascular permeability measured in isolated perfused lungs ex vivo increased at 2 wk after 15 Gy of irradiation. CONCLUSION: Our results suggest that SPECT biomarkers have the potential to predict radiation injury to the lungs before substantial functional or histologic damage is observed. Early prediction of radiation pneumonitis in time to initiate mitigation will benefit those exposed to radiation in the context of therapy, accidents, or terrorism.
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Bacteriocinas/farmacocinética , Imagen Molecular/métodos , Compuestos de Organotecnecio/farmacocinética , Neumonitis por Radiación/diagnóstico , Neumonitis por Radiación/metabolismo , Albúmina Sérica/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Compuestos de Estaño/farmacocinética , Tomografía Computarizada de Emisión de Fotón Único/métodos , Animales , Biomarcadores/metabolismo , Diagnóstico Precoz , Femenino , Radiofármacos/farmacocinética , Ratas , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
INTRODUCTION: Fluorescence guidance is an upcoming methodology to improve surgical accuracy. Challenging herein is the identification of the minimum dose at which the tracer can be detected with a clinical-grade fluorescence camera. Using a hybrid tracer such as indocyanine green (ICG)-(99m)Tc-nanocolloid, it has become possible to determine the accumulation of tracer and correlate this to intraoperative fluorescence-based identification rates. In the current study, we determined the lower detection limit of tracer at which intraoperative fluorescence guidance was still feasible. METHODS: Size exclusion chromatography (SEC) provided a laboratory set-up to analyze the chemical content and to simulate the migratory behavior of ICG-nanocolloid in tissue. Tracer accumulation and intraoperative fluorescence detection findings were derived from a retrospective analysis of 20 head-and-neck melanoma patients, 40 penile and 20 prostate cancer patients scheduled for sentinel node (SN) biopsy using ICG-(99m)Tc-nanocolloid. In these patients, following tracer injection, single photon emission computed tomography fused with computed tomography (SPECT/CT) was used to identify the SN(s). The percentage injected dose (% ID), the amount of ICG (in nmol), and the concentration of ICG in the SNs (in µM) was assessed for SNs detected on SPECT/CT and correlated with the intraoperative fluorescence imaging findings. RESULTS: SEC determined that in the hybrid tracer formulation, 41 % (standard deviation: 12 %) of ICG was present in nanocolloid-bound form. In the SNs detected using fluorescence guidance a median of 0.88 % ID was present, compared to a median of 0.25 % ID in the non-fluorescent SNs (p-value < 0.001). The % ID values could be correlated to the amount ICG in a SN (range: 0.003-10.8 nmol) and the concentration of ICG in a SN (range: 0.006-64.6 µM). DISCUSSION: The ability to provide intraoperative fluorescence guidance is dependent on the amount and concentration of the fluorescent dye accumulated in the lesion(s) of interest. Our findings indicate that intraoperative fluorescence detection with ICG is possible above a µM concentration.
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Neoplasias/diagnóstico por imagen , Neoplasias/cirugía , Imagen Óptica/métodos , Ganglio Linfático Centinela/diagnóstico por imagen , Cirugía Asistida por Computador/métodos , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Humanos , Neoplasias/metabolismo , Radiofármacos/farmacocinética , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Ganglio Linfático Centinela/metabolismo , Ganglio Linfático Centinela/cirugíaRESUMEN
UNLABELLED: Perfusion scintigraphy using (99m)Tc-labeled albumin aggregates is mandatory before hepatic radioembolization with (90)Y-microspheres. As part of a prospective trial, the intrahepatic and intrapulmonary stability of 2 albumin compounds, (99m)Tc-MAA (macroaggregated serum albumin [MAA]) and (99m)Tc-HSA (human serum albumin [HSA]), was assessed. METHODS: In 24 patients with metastatic colorectal cancer, biodistribution (liver, lung) and liver-lung shunt (LLS) of both tracers (12 patients each) were assessed by sequential planar scintigraphy (1, 5, and 24 h after injection). RESULTS: Liver uptake of both albumin compounds decreased differently. Although initial LLSs at 1 h after injection were similar in both groups, MAA-LLS increased significantly from 1 (3.9%) to 5 h (7.7%) and 24 h (9.9%) after injection, respectively. HSA-LLS did not change significantly (1 to 5 h), indicating a steady state of pulmonary and intrahepatic degradation. CONCLUSION: Compared with (99m)Tc-MAA-microspheres, (99m)Tc-HSA-microspheres are likely more resistant to degradation over time, allowing a reliable LLS determination even at later time points.
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Embolización Terapéutica , Hígado/metabolismo , Pulmón/metabolismo , Microesferas , Agregado de Albúmina Marcado con Tecnecio Tc 99m/química , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Anciano , Anciano de 80 o más Años , Neoplasias Colorrectales/patología , Femenino , Humanos , Hígado/diagnóstico por imagen , Hígado/efectos de la radiación , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/radioterapia , Neoplasias Hepáticas/secundario , Pulmón/diagnóstico por imagen , Pulmón/efectos de la radiación , Masculino , Persona de Mediana Edad , Imagen de Perfusión , Estudios Prospectivos , Distribución TisularRESUMEN
An 18-year-old man was preoperatively assessed for a varicocele and found to be hypoxemic. A Tc-99m macroaggregated albumin lung perfusion scan showed right-to-left shunting, evidenced by increased radiotracer uptake in the brain, kidneys, thyroid gland, and bilateral supraclavicular areas, a typical location for brown adipose tissue. Chest computerized tomography angiogram study showed supraclavicular fat density areas and multiple pulmonary arteriovenous malformations.The authors report a rare case of brown fat visualization on a lung perfusion scan in a patient with right-to-left shunting, likely because of increased perfusion to activated brown adipose tissue.
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Tejido Adiposo Pardo/diagnóstico por imagen , Tejido Adiposo Pardo/metabolismo , Malformaciones Arteriovenosas/diagnóstico por imagen , Malformaciones Arteriovenosas/metabolismo , Cardiopatías Congénitas/diagnóstico por imagen , Cardiopatías Congénitas/embriología , Pulmón/irrigación sanguínea , Pulmón/diagnóstico por imagen , Radiofármacos/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Adolescente , Malformaciones Arteriovenosas/complicaciones , Cardiopatías Congénitas/complicaciones , Humanos , Masculino , Cintigrafía , Distribución TisularRESUMEN
UNLABELLED: This study analyzed the predictive value of (99m)Tc-labeled macroaggregated albumin ((99m)Tc-MAA) SPECT for (90)Y-labeled resin microsphere therapy (radioembolization) by comparing uptake on pretherapeutic (99m)Tc-MAA SPECT with uptake on posttherapeutic (90)Y-bremsstrahlung SPECT. METHODS: We included 502 patients (55% male; mean age ± SD, 62 ± 11 y) who underwent radioembolization between 2005 and 2013 because of primary or secondary liver malignancies (colorectal cancer [n = 195, 38.8%], neuroendocrine tumors [n = 77, 15.3%], breast cancer [n = 68, 13.5%], hepatocellular carcinoma [n = 59, 11.8%], cholangiocellular carcinoma [n = 40, 8.0%], or urologic tumors [n = 14, 2.8%]). Manually drawn regions of interest around tumors and adjacent healthy liver tissue for up to 3 lesions per patient on (99m)Tc-MAA and (90)Y-bremsstrahlung scans were used to quantify mean counts per pixel and evaluate the mean tumor-to-background ratio (TBR). Data were given as mean ± SD. Additionally, uptake in lesions on (99m)Tc-MAA and (90)Y-bremsstrahlung scans was graded visually as homogeneously higher than (grade 1), heterogeneously higher than (grade 2), equal to (grade 3), or lower than (grade 4) uptake in normal liver tissue. The Mann-Whitney U test and Spearman correlation were used to evaluate statistically significant differences between (99m)Tc-MAA and (90)Y-bremsstrahlung SPECT. RESULTS: In total, 1,008 lesions were analyzed. Of the 23% (230/1,008) of lesions that had grade 1 uptake on (99m)Tc-MAA SPECT, 81% (186/230) remained grade 1 after radioembolization whereas 16% (37/230) were grade 2. Of the lesions with grade 2 uptake on (99m)Tc-MAA SPECT, 16% had grade 1 uptake and 82% grade 2 uptake after radioembolization. Of the lesions with grade 3 uptake, however, 27% had grade 1 uptake and 47% grade 2 uptake after radioembolization. Even among the lesions with grade 4 uptake on (99m)Tc-MAA SPECT, 21% had grade 1 uptake and 46% grade 2 uptake after radioembolization. The mean TBR on (99m)Tc-MAA and (90)Y-bremsstrahlung SPECT showed a significant, though low, correlation in the total population (r = 0.26; P < 0.001) and in hepatocellular carcinoma (r = 0.4; P < 0.001), cholangiocellular carcinoma (r = 0.3; P < 0.05), breast cancer (r = 0.3; P < 0.001), colorectal cancer (r = 0.2; P < 0.001), and neuroendocrine tumors (r = 0.2; P < 0.01). CONCLUSION: Although significant for most lesions, the correlation between (99m)Tc-MAA and (90)Y-microsphere mean TBR was low. Classifying uptake into 4 grades revealed that lesions with high uptake on (99m)Tc-MAA SPECT maintain high uptake within radioembolization. More than 60% of lesions with a pretherapeutically lower uptake than in healthy liver tissue, however, showed high uptake within radioembolization. Patients with low tumor uptake on pretherapeutic (99m)Tc-MAA imaging should not be excluded from radioembolization.
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Embolización Terapéutica/métodos , Neoplasias Hepáticas/radioterapia , Radiofármacos , Agregado de Albúmina Marcado con Tecnecio Tc 99m , Tomografía Computarizada de Emisión de Fotón Único/métodos , Radioisótopos de Itrio , Adulto , Anciano , Anciano de 80 o más Años , Angiografía , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Neoplasias Hepáticas/secundario , Masculino , Microesferas , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Radiofármacos/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Distribución Tisular , Radioisótopos de Itrio/farmacocinéticaRESUMEN
OBJECTIVE: (99m)Tc macroaggregated albumin ((99m)Tc-MAA) that had been used as a perfusion agent has been evaluated. In this study, we tried to estimate human absorbed dose of 68Ga-MAA via commercially available kit from Pars-Isotopes, based on biodistribution data in wild-type rats, and compare our estimation with the available absorbed dose data from (99m)Tc-MAA. METHODS: For biodistribution of 68Ga-MAA, three rats were sacrificed at each selected times after injection (15, 30, 45, 60, and 120 min) and the percentage of injected dose per gram of each organ was measured by direct counting from rats data from 11 harvested organs. The medical internal radiation dose formulation was applied to extrapolate from rats to human and to project the absorbed radiation dose for various organs in humans. RESULTS: The biodistribution data for 68Ga-MAA showed that the most of the activity was taken up by the lung (more than 97 %) in no time. Our dose prediction shows that a 185-MBq injection of 68Ga-MAA into humans might result in an estimated absorbed dose of 4.31 mGy in the whole body. The highest absorbed doses are observed in the adrenals, spleen, pancreas, and red marrow with 0.36, 0.34, 0.26, and 0.19 mGy, respectively. CONCLUSION: Since the (99m)Tc-MAA remains longer than 68Ga-MAA in the lung and 68Ga-MAA has good image qualities and results in lower amounts of dose delivery to the critical organs such as gonads, red marrow, and adrenals, the use of 68Ga-MAA is recommended.
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Compuestos Organometálicos , Dosis de Radiación , Albúmina Sérica , Agregado de Albúmina Marcado con Tecnecio Tc 99m , Animales , Humanos , Compuestos Organometálicos/farmacocinética , Tomografía de Emisión de Positrones , Ratas , Albúmina Sérica/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Distribución TisularRESUMEN
A 50-year-old woman presented to our institution with a 1-day history of right posterior thoracic pain and dyspnea. She had a previous history of conservative resection of a high-grade basal-like infiltrating ductal carcinoma of the right breast 2 years before, subsequently treated by chemotherapy and radiotherapy. A ventilation and perfusion (VQ) scintigraphy performed for suspected pulmonary embolism showed an abnormal deposition of (99m)Tc macroaggregated albumin ((99m)Tc-MAA) in the left lobe of the liver. This unusual finding prompted additional imaging that demonstrated a superior vena cava stenosis.
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Constricción Patológica/diagnóstico por imagen , Hígado/diagnóstico por imagen , Imagen de Perfusión , Radiofármacos/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Tomografía Computarizada de Emisión de Fotón Único , Tomografía Computarizada por Rayos X , Vena Cava Superior/diagnóstico por imagen , Femenino , Humanos , Persona de Mediana Edad , Imagen Multimodal , Vena Cava Superior/patologíaAsunto(s)
Hígado/diagnóstico por imagen , Linfedema/diagnóstico por imagen , Linfocintigrafia/métodos , Radiofármacos/sangre , Agregado de Albúmina Marcado con Tecnecio Tc 99m/sangre , Conducto Torácico/diagnóstico por imagen , Humanos , Inyecciones Subcutáneas , Hígado/metabolismo , Extremidad Inferior , Linfedema/sangre , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Radiografía , Radiofármacos/administración & dosificación , Radiofármacos/farmacocinética , Agregado de Albúmina Marcado con Tecnecio Tc 99m/administración & dosificación , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Conducto Torácico/metabolismoRESUMEN
BACKGROUND: Computer modeling is used to predict inhaled aerosol deposition in the lung based on definition of the aerosol characteristics and the breathing pattern and airway anatomy of the subject. Validation of the models is limited by the lack of detailed experimental data. Three-dimensional imaging provides an opportunity to address this unmet need. METHODS: Radioactive aerosol was administered to six male asthmatic subjects on two occasions under carefully monitored input conditions. Input parameters varied in particle size, depth of breathing, and carrier gas. The aerosol distribution was measured by combined single photon emission computed tomography and x-ray computer tomography (SPECT/CT) and airway anatomy by high resolution CT. The deposition distribution was measured by both a 2D and 3D analysis and described in terms of the percentage of inhaled aerosol deposited in sections of the respiratory tract and in both spatial and anatomical subdivisions within each lung. The percentage deposition in the conducting airways was also assessed by 24 h clearance. RESULTS: A set of imaging data of aerosol deposition has thus been produced in which the input parameters of inhalation are well described. The results in asthmatics were compared to previous measurements in healthy controls using an identical inhalation protocol. The percentages of deposition in extra-thoracic and thoracic compartments of the airways were not significantly affected by disease, but the regional pulmonary deposition pattern was, with asthma leading to increased deposition in the conducting airways. CONCLUSIONS: The dataset acquired in this study will be useful in validating computer models of aerosol deposition in asthmatic subjects. Asthma did not affect the fraction of inhaled aerosol depositing in the lungs, but gave rise to a more central deposition pattern. The use of 3D SPECT imaging in combination with 24 h clearance measurements enables differentiation of deposition between bronchial and bronchiolar airways.
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Asma/diagnóstico por imagen , Imagenología Tridimensional , Pulmón/diagnóstico por imagen , Modelos Biológicos , Imagen Multimodal/métodos , Radiofármacos/administración & dosificación , Absorción a través del Sistema Respiratorio , Agregado de Albúmina Marcado con Tecnecio Tc 99m/administración & dosificación , Tomografía Computarizada de Emisión de Fotón Único , Administración por Inhalación , Adulto , Aerosoles , Asma/metabolismo , Asma/fisiopatología , Humanos , Pulmón/metabolismo , Pulmón/fisiopatología , Masculino , Persona de Mediana Edad , Tamaño de la Partícula , Valor Predictivo de las Pruebas , Radiofármacos/farmacocinética , Reproducibilidad de los Resultados , Mecánica Respiratoria , Agregado de Albúmina Marcado con Tecnecio Tc 99m/farmacocinética , Tomografía Computarizada por Rayos X , Adulto JovenRESUMEN
OBJECTIVE: Near-infrared (NIR) fluorescence imaging using indocyanine green (ICG) has recently been introduced to improve the sentinel lymph node (SLN) procedure. Several optical tracers have been successfully tested. However, the optimal tracer formulation is still unknown. This study evaluates the performance of ICG-technetium-99m (99mTc)-nanocolloid in relation to 2 most commonly used ICG-based formulas during SLN biopsy in vulvar cancer. METHODS AND MATERIALS: Twelve women who planned to undergo SLN biopsy for stage I vulvar cancer were prospectively included. Sentinel lymph node mapping was performed using the dual-modality radioactive and NIR fluorescence tracer ICG-99mTc-nanocolloid. All patients underwent combined SLN localization using NIR fluorescence and the (current) gold standard using blue dye and radioactive guidance. RESULTS: In all 12 patients, at least 1 SLN was detected during surgery. A total of 21 lymph nodes (median 2; range, 1-3) were resected. Median time between skin incision and first SLN detection was 8 (range, 1-22) minutes. All resected SLNs were both radioactive and fluorescent, although only 13 (62%) of 21 SLNs stained blue. Median brightness of exposed SLNs, expressed as signal-to-background ratio, was 5.4 (range, 1.8-11.8). Lymph node metastases were found in 3 patients. CONCLUSIONS: Near-infrared fluorescence-guided SLN mapping is feasible and outperforms blue dye staining. Premixing ICG with 99mTc-nanocolloid provides real-time intraoperative imaging of the SN and seems to be the optimal tracer combination in terms of intraoperative detection rate of the SN (100%). Moreover, ICG-99mTc-nanocolloid allows the administration of a 5-times lower injected dose of ICG (compared with ICG and ICG absorbed to human serum albumin) and can be injected up to 20 hours before surgery.