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Liposomes, with their flexible physicochemical and biophysical properties, continue to be studied as an important potential a critical drug delivery system. Liposomes have overcome the challenges of conventional free drug therapy by encapsulating therapeutic agents, thereby improving in vivo biodistribution and reducing systemic toxicity. New imaging modalities and interpretation techniques, as well as new techniques for targetable system formulation technique, and tumor environmental information, have affected the search for a means of overcoming the difficulties of conventional liposome formulation. In this review, we briefly discuss how liposomal formulation has been applied across the biomedical field, particularly as a therapy, and the role it may play in the future, when paired with new developments in diagnosis and theranostics. The biological challenges that still remain and the translational obstacles are discussed.
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This year, the Korean Society of Nuclear Medicine (KSNM) is celebrating its 60th anniversary. Treatment, as well as diagnosis, has played a very important role in the development of nuclear medicine. Since I-131 was used for thyroid therapy in 1959, other radionuclide therapy is still being used, and attempts to use new radionuclide are increasing. In this review, we briefly summarize and introduce the therapies such as radioimmunotherapy, transarterial radioembolization, radionuclide therapy for neuroendocrine tumors, peptide receptor radionuclide therapy, control of metastatic bone pain, radiation synovectomy, radionuclide brachytherapy, alpha particle therapy, and boron neutron capture therapy, which has been being attempted so far in the field of nuclear medicine.
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Purpose@#This study aimed to investigate the effect of ursodeoxycholic acid (UDCA) on the biodistribution and excretion of technetium-99m (Tc-99m)-labeled radiopharmaceuticals. @*Materials and Methods@#Tc-99m hydroxy-methylene-diphosphonate (HDP), Tc-99m pertechnetate, and Tc-99m dimercaptosuccinic acid (DMSA) were injected via the tail vein of rats. After 30 min, the control group was administered saline, and the UDCA group was given UDCA orally. Scintigraphy images were acquired after 30 min and 1, 2, 3, and 4 h. Radioactivity and rate of change were compared. Tc-99m mercaptoacetyltriglycine (MAG3) imaging was also performed. @*Results@#In image analysis of Tc-99m HDP, radioactivity of the buttock was lower in the UDCA group at 4 h. Rates of change in the buttock were significantly different at 3 h–30 min and 4 h–30 min, and buttock radioactivity in the UDCA group had decreased more. In analysis of Tc-99m pertechnetate, radioactivity of the buttock was higher in the control group. Rates of change in the thyroid gland and buttock were different at 1 h–30 min, 3 h–30 min, and 4 h–30 min, with radioactivity in the UDCA group decreasing more. In the analysis of Tc-99m DMSA, while the radioactivity of the kidneys in the control group showed little decrease at 1 h–30 min, that in the UDCA group increased. In the analysis of Tc-99m MAG3 images, radioactivity and radioactivity/total body radioactivity (TBA) values for the kidneys were higher in the UDCA group at 2 min. At 5 and 10 min, radioactivity/TBA values for soft tissue in the UDCA group were lower than those in the control group. @*Conclusion@#This study demonstrated that administration of UDCA increases renal excretion and soft tissue clearance of radiopharmaceuticals. This investigation could contribute to the broadening of applications of UDCA.
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Background@#Pharmacological and non-pharmacological therapies have been used to treat patients with chemotherapy-induced peripheral neuropathy (CIPN). However, the effect of therapies in cancer patients has yet to be investigated comprehensively. We hypothesized that cyclic thermal therapy would improve blood flow and microcirculation and improve the symptoms driven by CIPN. @*Methods@#The criteria of assessment were blood volume in region of interest (ROI) in the images, and European Organization for Research and Treatment of Cancer–Quality of Life Questionnaire–Chemotherapy-Induced Peripheral Neuropathy 20 questionnaire scores. The blood volume was quantified by using red blood cell (RBC) scintigraphy. All patients were treated 10 times during 10 days. The thermal stimulations, between 15° and 41°, were repeatedly delivered to the patient’s hands. @*Results@#The total score of the questionnaires, the score of questions related to the upper limbs, the score of questions closely related to the upper limbs, and the score excluding the upper limbs questions was decreased. The blood volume was decreased, and the variance of blood volume was decreased. During cooling stimulation, the blood volume was decreased, and its variance was decreased. During warming stimulation, the blood volume was decreased, and its variance was decreased. @*Conclusions@#We suggest that cyclic thermal therapy is useful to alleviate CIPN symptoms by blood circulation improvement. RBC scintigraphy can provide the quantitative information on blood volume under certain conditions such as stress, as well as rest, in peripheral tissue.
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Purpose@#This study aimed to investigate the effect of ursodeoxycholic acid (UDCA) on the biodistribution and excretion of technetium-99m (Tc-99m)-labeled radiopharmaceuticals. @*Materials and Methods@#Tc-99m hydroxy-methylene-diphosphonate (HDP), Tc-99m pertechnetate, and Tc-99m dimercaptosuccinic acid (DMSA) were injected via the tail vein of rats. After 30 min, the control group was administered saline, and the UDCA group was given UDCA orally. Scintigraphy images were acquired after 30 min and 1, 2, 3, and 4 h. Radioactivity and rate of change were compared. Tc-99m mercaptoacetyltriglycine (MAG3) imaging was also performed. @*Results@#In image analysis of Tc-99m HDP, radioactivity of the buttock was lower in the UDCA group at 4 h. Rates of change in the buttock were significantly different at 3 h–30 min and 4 h–30 min, and buttock radioactivity in the UDCA group had decreased more. In analysis of Tc-99m pertechnetate, radioactivity of the buttock was higher in the control group. Rates of change in the thyroid gland and buttock were different at 1 h–30 min, 3 h–30 min, and 4 h–30 min, with radioactivity in the UDCA group decreasing more. In the analysis of Tc-99m DMSA, while the radioactivity of the kidneys in the control group showed little decrease at 1 h–30 min, that in the UDCA group increased. In the analysis of Tc-99m MAG3 images, radioactivity and radioactivity/total body radioactivity (TBA) values for the kidneys were higher in the UDCA group at 2 min. At 5 and 10 min, radioactivity/TBA values for soft tissue in the UDCA group were lower than those in the control group. @*Conclusion@#This study demonstrated that administration of UDCA increases renal excretion and soft tissue clearance of radiopharmaceuticals. This investigation could contribute to the broadening of applications of UDCA.
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Background@#Pharmacological and non-pharmacological therapies have been used to treat patients with chemotherapy-induced peripheral neuropathy (CIPN). However, the effect of therapies in cancer patients has yet to be investigated comprehensively. We hypothesized that cyclic thermal therapy would improve blood flow and microcirculation and improve the symptoms driven by CIPN. @*Methods@#The criteria of assessment were blood volume in region of interest (ROI) in the images, and European Organization for Research and Treatment of Cancer–Quality of Life Questionnaire–Chemotherapy-Induced Peripheral Neuropathy 20 questionnaire scores. The blood volume was quantified by using red blood cell (RBC) scintigraphy. All patients were treated 10 times during 10 days. The thermal stimulations, between 15° and 41°, were repeatedly delivered to the patient’s hands. @*Results@#The total score of the questionnaires, the score of questions related to the upper limbs, the score of questions closely related to the upper limbs, and the score excluding the upper limbs questions was decreased. The blood volume was decreased, and the variance of blood volume was decreased. During cooling stimulation, the blood volume was decreased, and its variance was decreased. During warming stimulation, the blood volume was decreased, and its variance was decreased. @*Conclusions@#We suggest that cyclic thermal therapy is useful to alleviate CIPN symptoms by blood circulation improvement. RBC scintigraphy can provide the quantitative information on blood volume under certain conditions such as stress, as well as rest, in peripheral tissue.
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Purpose@#The objective of this study was to describe to develop methods of rodent leukocyte isolation and radiolabeling for in vivo inflammation imaging. @*Methods@#Thigh muscle inflammation was induced by injection of collagenase. Blood was collected from the jugular vein and separated by Histopaque. The collected cells were incubated in a 37 °C CO2 incubator for 1~2 h. After incubation, 99mTc-HMPAO and 18F-FDG were used to treat leukocytes followed by incubation for 30 min. 99mTc-HMPAO and 18F-FDG labeled autologous leukocytes were injected into the tail veins of rats. The images were then acquired at various time points. Image-based lesion to normal muscle ratio was compared. @*Results@#After Histopaque separation, the proportion of lymphocytes was higher than that of other cell types. After CO2 incubation, the collected leukocytes were viable, while room temperature exposed leukocytes without CO2 incubation were non-viable. Granulocytes, especially, were more quickly influenced by various conditions than the mononuclear cells. Labeling efficiencies of 99mTc-HMPAO and 18F-FDG were 4.00 ± 2.06 and 1.8%, respectively. 99mTc-HMPAO- and 18F-FDG-labeled leukocytes targeted well the inflamed lesion. 99mTc-HMPAO-labeled leukocytes, but not 18F-FDG-labeled leukocytes, were found in the abdomen activity. @*Conclusion@#Inflamed lesions of rats were well visualized using autologous radiolabeled leukocytes. This method might provide good information for understanding inflammatory diseases.
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Purpose@#2-Deoxy-2-[18F] fluoro-d-glucose positron emission tomography (18F-FDG-PET) is a less-invasive and widely useddiagnostic tool for detection of malignant tumors. However, prolonged retention of 18F-FDG in the body increases radiationexposure. This study evaluated the effect of oral administration of milk and ursodeoxycholic acid (UDCA) in terms of reducingradiation exposure by 18F-FDG. @*Methods@#18F-FDG radioactivity was measured using a digital γ counter in the whole body and in various organs of rats after oraladministration of milk andmilk plusUDCA (milk + UDCA).Western blotting was performed to measure the expression levels ofG6Pase, HK 2, CREB, FoxO1, and PGC-1α in the brain, liver, small intestine, and large intestine to assess the mechanismunderlying the reduction in radiation exposure from 18F-FDG by oral administration of milk and UDCA. @*Results@#We found a significant reduction in 18F-FDG radioactivity in the whole body and in the brain, liver, and small and largeintestines. Expression of G6Pase was significantly increased in the above-mentioned organs in the milk and milk + UDCAgroups. Expression of HK 2 was significantly decreased in the brain and small intestine in the milk and milk + UDCA groups.CREB, FoxO1, and PGC-1α expression levels in the brain, liver, and small intestine were increased in the milk and milk +UDCA groups. However, expression of PGC-1α in the large intestine in the milk and milk + UDCA groups was significantlydecreased compared with that in the control group. @*Conclusion@#The present study demonstrated that administration of milk and UDCA increased G6Pase expression levels and 18FFDGrelease from the tissue. These results suggest milk and UDCA could be used to reduce radiation exposure from 18F-FDGafter image acquisition. The mechanisms underpinning this phenomenon should be explored in a human study.
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Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a slowing progressive ataxic disorder characterized by bilateral vestibulopathy, cerebellar ataxia and somatosensory impairment. Autonomic dysfunction is recently considered as a core feature in CANVAS in addition to these symptoms. In most cases, patients with CANVAS show cerebellar atrophy in brain imaging, but some cases show minimal or no atrophy of cerebellum. Brain (18F)-fluoro-2-deoxy-D-glucose positron emission tomography (¹⁸F-FDG PET) study can be a complimentary tool to diagnosis CANVAS in cases of no structural abnormality such as cerebellar atrophy. Hereby, we present a case of CANVAS with minimal atrophy of cerebellum but showing a prominent hypometabolism in cerebellum, thalamus and posterior cingulate cortex in ¹⁸F-FDG PET.
Subject(s)
Humans , Atrophy , Brain , Cerebellar Ataxia , Cerebellum , Diagnosis , Gyrus Cinguli , Neuroimaging , Positron-Emission Tomography , Primary Dysautonomias , Thalamus , Vestibular NeuronitisABSTRACT
Nanotechnology is the engineering and manipulation of materials and devices with sizes in the nanometer range. Colloidal gold, iron oxide nanoparticles and quantum dot semiconductor nanocrystals are examples of nanoparticles, with sizes generally ranging from 1 to 20 nm. These nanotechnologies have been researched tremendously in the last decade and this has led to a new area of “nanomedicine” which is the application of nanotechnology to human healthcare for diagnosis, monitoring, treatment, prediction and prevention of diseases. Recently progress has been made in overcoming some of the difficulties in the human use of nanomedicines. In the mid-1990s, Doxil was approved by the FDA, and now various nanoconstructs are on the market and in clinical trials. However, there are many obstacles in the human application of nanomaterials. For translation to clinical use, a detailed understanding is needed of the chemical and physical properties of particles and their pharmacokinetic behavior in the body, including their biodistribution, toxicity, and biocompatibility. In this review, we provide a broad introduction to nanomedicines and discuss the preclinical and clinical trials in which they have been evaluated.
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Humans , Delivery of Health Care , Diagnosis , Gold Colloid , Iron , Nanomedicine , Nanoparticles , Nanostructures , Nanotechnology , Quantum DotsABSTRACT
Colloidal particle size is an important characteristic that allows mapping sentinel nodes in lymphoscintigraphy. This investigation aimed to introduce different ways of making a 99mTc-tin colloid with a size of tens of nanometers. All agents, tin fluoride, sodium fluoride, poloxamer-188, and polyvinylpyrrolidone (PVP), were mixed and labeled with 99mTc. Either phosphate or sodium bicarbonate buffers were used to adjust the pH levels. When the buffers were added, the size of the colloids increased. However, as the PVP continued to increase, the size of the colloids was controlled to within tens of nanometers. In all samples, phosphate buffer added PVP (30 mg) stabilized tin colloid (99mTc-PPTC-30) and sodium bicarbonate solution added PVP (50 mg) stabilized tin colloid (99mTc-BPTC-50) were chosen for in vitro and in vivo studies. 99mTc-BPTC-50 (100 nm) mainly accumulated in the liver. When a rabbit was given a toe injection, the node uptake of 99mTc-PPTC-30 decreased over time, while 99mTc-BPTC-50 increased. Therefore, 99mTc-BPTC-50 could be a good candidate radiopharmaceutical for sentinel node detection. The significance of this study is that nano-sized tin colloid can be made very easily and quickly by PVP.
Subject(s)
Animals , Humans , Mice , Rabbits , Buffers , Cell Line, Tumor , Lymph Nodes/diagnostic imaging , Lymphatic Metastasis , Metal Nanoparticles/chemistry , Neoplasms, Experimental/diagnostic imaging , Particle Size , Povidone/chemistry , Radiopharmaceuticals/chemical synthesis , Reproducibility of Results , Sensitivity and Specificity , Technetium Compounds/chemistry , Tin/chemistry , Tin Compounds/chemistryABSTRACT
BACKGROUND: 67Ga scintigraphy has been used for years in sarcoidosis for diagnosis and to determine the extent of the disease. The present report is a study of various findings of 67Ga scintigraphy in patients with sarcoidosis. METHODS: Between 1998 and 2007, 16 patients (male:female, 6:10; age, 35.9+/-15.3 years) with histologically proven sarcoidosis underwent clinical evaluation and 67Ga scintigraphy. According to the site of involvement, they were divided into subtypes and analyzed. RESULTS: Sixteen patients with sarcoidosis had involvement of various organs, including lymph nodes (13/16, 81.3%), lung (3/16, 18.8%), muscle (1/16, 6.3%), subcutaneous tissue (1/16, 6.3%), glands (1/16, 6.3%), and bone (1/16, 6.3%). Sites of involved lymph nodes were thorax (12/13, 92.3%), supraclavicular area (5/13, 38.5%), inguinal area (2/13, 15.4%), abdomen (2/13, 15.4%), and pelvis (1/13, 7.7%). CONCLUSION: Because sarcoidosis frequently involves multiple organs, 67Ga scintigraphy is a useful method in for evaluating the whole body. Nuclear medicine physicians should be familiar with the various findings of gallium uptake in sarcoidosis.
Subject(s)
Humans , Abdomen , Gallium , Gallium Radioisotopes , Lung , Lymph Nodes , Muscles , Nuclear Medicine , Pelvis , Sarcoidosis , Subcutaneous Tissue , ThoraxABSTRACT
Malignant mesothelioma of the peritoneum is a rare neoplasm with a rapidly fatal course. The tumour arises from the mesothelial cells lining the pleura and peritoneum or, rarely, in the pericardium or tunica vaginalis. This neoplasm is characterized by being difficult to diagnose, having a rapid evolution and a poor response to therapy. Mesothelioma is very glucose avid, and malignant pleural mesothelioma has been reported concerning the utility of F-18 FDG PET or PET/CT. But little has been known about the imaging finding of malignant peritoneal mesothelioma on F-18 FDG PET/CT. We report a case of malignant peritoneal mesothelioma mimicking peritoneal carcinomatosis of F-18 FDG PET/CT.
Subject(s)
Carcinoma , Glucose , Mesothelioma , Pericardium , Peritoneum , PleuraABSTRACT
Ga-67 scintigraphy demonstrated increased uptake in the lungs and stomach in a 26-year-old man with hypercalcemia. A primitive neuroectodermal tumor was confirmed by bone marrow examination. Tc-99m MDP uptake in the same locations as Ga-67 revealed by bone scintigraphy was consistent with metastatic calcification. Although the mechanism of Ga-67 uptake in metastatic calcification is not understood, the presence of an inflammatory process is suggested.
Subject(s)
Adult , Humans , Bone Marrow Examination , Citrates , Citric Acid , Gallium , Hypercalcemia , Lung , Neuroectodermal Tumors, Primitive , Stomach , Technetium Tc 99m MedronateABSTRACT
Noninvasive imaging of molecular and biological processes in living subjects with positron emission tomography (PET) provides exciting opportunities to monitor metabolism and detect diseases in humans. Measuring these processes with PET requires the preparation of specific molecular imaging probes labeled with 18F-fluorine. In this review we describe recent methods and novel trends for the introduction of 18F-fluorine into molecules which in turn are intended to serve as imaging agents for PET study. Nucleophilic 18F-fluorination of some halo- and mesyloxyalkanes to the corresponding 18F-fluoroalkanes with 18F-fluoride obtained from an 18O(p,n)18F reaction, using novel reaction media system such as an ionic liquidor tert-alcohol, has been studied as a new method for 18F-fluorine labeling. Ionic liquid method is rapid and particularly convenient because 18F-fluoride in H2O can be added directly to the reaction media, obviating the careful drying that is typically required for currently used radiofluorination methods. The nonpolar protic tert-alcohol enhances the nucleophilicity of the fluoride ion dramatically in the absence of any kind of catalyst, greatly increasing the rate of the nucleophilic fluorination and reducing formation of byproducts compared with conventional methods using dipolar aprotic solvents. The great efficacy of this method is a particular advantage in labeling radiopharmaceuticals with 18F-fluorine for PETimaging, and it is illustrated by the synthesis of 18F-fluoride radiolabeled molecular imaging probes, such as 18F-FDG, 18F-FLT, 18F-FP-CIT, and 18F-FMISO, in high yield and purity and in shorter times compared to conventional syntheses
Subject(s)
Humans , Biological Phenomena , Dideoxynucleosides , Fluorides , Fluorodeoxyglucose F18 , Halogenation , Imidazoles , Misonidazole , Molecular Imaging , Nitro Compounds , Organothiophosphorus Compounds , Positron-Emission Tomography , Radiopharmaceuticals , SolventsABSTRACT
A 45-year-old man presented with fatigue and weight loss underwent a Tc-99m MDP bone scan because of increased serum alkaline phosphatase. Delayed images at 4 hours demonstrated diffuse increased activity throughout both lobes of the thyroid in the absence of activity of the stomach and salivary glands. Thyroid laboratory indices and a Tc-99m pertechnetate thyroid scan suggested Graves' hyperthyroidism.
Subject(s)
Humans , Middle Aged , Alkaline Phosphatase , Fatigue , Graves Disease , Hyperthyroidism , Salivary Glands , Sodium Pertechnetate Tc 99m , Stomach , Technetium Tc 99m Medronate , Thyroid Gland , Weight LossABSTRACT
PURPOSE: Increased FDG uptake in the bone marrow has been reported in patients taking erythropoietin or granulocyte-colony stimulating factor (G-CSF). The aim of this study is to investigate the correlation between F-18 FDG uptake in the bone marrow and bone marrow finding, hematological parameters. MATERIALS AND METHODS: Twenty patients who had diffuse FDG uptake at the bone marrow and received hematological examinations, bone marrow biopsy within 10 days before or after PET/CT were enrolled in this study. Among them, 11 patients were excluded; 4 patients received G-CSF or erythropoietin before PET/CT. Seven patients showed definite pathology in a bone marrow biopsy. The parameters included the measurement of WBC, hemoglobin, platelet and cellularity of the bone marrow. RESULTS: Bone marrow FDG uptake was correlated with a low hemoglobin but not WBC, platelet. Histopathologic findings in marrow biopsies were various: normal finding (n=3), hyperplasia of granulocytic cells (n=2), eosinophilic hyperplasia (n=1), reactive lymphoid nodules (n=1), hypercelluar marrow (n=1), hypocelluar marrow (n=1). All patients except two, showed normal marrow celluarity. CONCLUSION: FDG uptake by bone marrow correlated with anemia but not WBC, platelet, bone marrow cellularity.
Subject(s)
Humans , Anemia , Biopsy , Blood Cell Count , Blood Cells , Blood Platelets , Bone Marrow , Bone Marrow Examination , Eosinophils , Erythropoietin , Granulocyte Colony-Stimulating Factor , Hemoglobins , HyperplasiaABSTRACT
Kasabach-Merritt syndrome (KMS) consists of thrombocytopenia, microangiopathic hemolytic anemia, and localized consumption coagulopathy that develops within vascular hemangioma. This syndrome may also be associated with occult hemangiomas located at various sites. Tc-99m RBC scintigraphy and SPECT have proven to be reliable for confirming or excluding hemangioma. Total body blood pool imaging study during the scintigraphy also provides a means of screening for occult lesions. The authors report the case of a 29-year-old man who presented with a giant hepatic hemangioma complicated by KMS, and underwent Tc-99m RBC scintigraphy and SPECT including a total body blood pool imaging study.
Subject(s)
Adult , Humans , Anemia, Hemolytic , Disseminated Intravascular Coagulation , Hemangioma , Kasabach-Merritt Syndrome , Mass Screening , Thrombocytopenia , Tomography, Emission-Computed, Single-PhotonABSTRACT
PURPOSE: This study was to investigate the clinical significance of diffusely increased F-18 FDG uptake in the thyroid gland as an incidental finding on F-18 FDG PET/CT imaging in patients with breast carcinoma. METHODS: One hundred four patients with breast carcinoma who had no prior history of thyroid disease were enrolled. All patients underwent F-18 FDG PET/CT, ultrasound and thyroid function test (TFT-TSH, FT4, and T3), anti-TPO antibody test within 2 weeks. Also we checked estrogen (ER) and progesterone receptors (PR). We classified all patients into subgroups according to the existence and degree of F-18 FDG uptake in the thyroid gland, and evaluated the difference between subgroups. RESULTS: Of the 104 patients, 42 (40.4%) subjects showed diffusely increased thyroid uptakes. There was no significant difference in rate of abnormality in TFT and thyroid US, and existence of anti-TPO antibody and ER/PR between two groups. Of 42 patient who showed diffuse uptake, 12 (28.5%), 13 (31.0%), and 17 (40.5%) subjects demonstrated hypointense, isointense, and hyperintense thyroid uptake compared with activity of mediastinal blood pool. Thirteen (76.4%) of 17 subjects in the hyperintense thyroid uptake group revealed abnormality in various tests (US, TFT, and anti-TPO antibody). The rate of abnormality in this group was significantly different with the other two groups (p=0.002). CONCLUSION: Our data suggested that the rate of diffuse thyroid uptakes on F-18 FDG PET/CT imaging of patients with breast carcinoma was higher than healthy subjects. In case of someone who had no prior thyroid disease showed diffuse thyroid uptakes more than activity of mediastinal blood pool on F-18 FDG PET/CT imaging, it should be considered further evaluation about the thyroid gland.
Subject(s)
Humans , Breast , Breast Neoplasms , Estrogens , Incidental Findings , Receptors, Progesterone , Thyroid Diseases , Thyroid Function Tests , Thyroid GlandABSTRACT
PURPOSE: F-18 FDG can be accumulated in the liver, bowel, kidney, urinary tract, and muscles physiologically. The aim of this study was to evaluate the clinical value of dual time point 18F-FDG PET/CT imaging for the differentiation of the colonic focal uptake lesions. MATERIALS AND METHODS: One hundred thirty two patients (M:F=77:55, Age 62.8 +/-11.6 years) underwent 18F-FDG PET/CT at two time points, prospectively: early image at 50-60 min and delayed image at 4-4.5 hours after the intravenous injection of 18F-FDG. Focally increased uptake lesions on early images but disappeared or shifted on delayed images defined a physiological uptake. For the differential evaluation of persistent focal uptake lesions on delayed images, colonoscopy and histopathologic examination were performed. SUVmax changes between early and delayed images were also compared. RESULTS: Among the 132 patients, 153 lesions of focal colonic uptake were detected on early images of 18F-FDG PET/CT. Of these, 72 (47.1%) lesions were able to judge with physiological uptake because the focal increased uptake disappeared from delayed image. Among 81 lesions which was showed persistent increased uptake in delayed image, 61 (75.3%) lesions were confirmed as the malignant tumor and 14 (17.3%) lesions were confirmed as the benign lesions including adenoma and inflammatory disease. Remaining 6 (7.4%) lesions were confirmed as the physiological uptake because there was no particular lesion in the colonoscopy. In the malignant lesions, the calculated dual time point change for SUVmax (delta%SUVmax) was 20.8%+/-18.7%, indicating a significant increase in SUVmax between the two point (p<0.01). In contrast, the change in SUVmax for the non-malignant lesions including benign lesions and physiological uptake was -13.7%+/-24.2%. For the differentiation of the malignant and non-malignant focal colonic uptake lesions, delta%SUVmax was the most effective parameter, and the cut-off value using -5% provided the best sensitivity, specificity, and accuracy. CONCLUSION: The dual time point 18F-FDG PET/CT imaging with SUVmax change evaluation could be an important noninvasive method for the differentiation of malignant and benign focal colonic uptake lesions including physiologic uptake.