Scintigraphic Techniques Research Articles

Metabolic Comparison of Radiolabeled Bleomycin and Bleomycin-Glucuronide Labeled with 99mTc

The metabolic comparison of bleomycin (BLM) and bleomycin-glucuronide (BLMG) radiolabeled with (99m)Tc ((99m)Tc-BLM and (99m)Tc-BLMG, respectively) has been investigated in this study. Quality control procedures were carried out using thin-layer radiochromatography and high-performance liquid chromatography. To compare the metabolic behavior of BLM and its glucuronide conjugate radiolabeled with (99m)Tc, scintigraphic, and biodistributional techniques were applied using male New Zealand rabbits and Albino Wistar rats. The results obtained have shown that these compounds were successfully radiolabeled with a labeling yield of about 100%. Maximum uptakes of (99m)Tc-BLM and (99m)Tc-BLMG metabolized as N-glucuronide were observed within 2 hours in the liver, the bladder, and the spinal cord for (99m)Tc-BLM and the lung, the liver, the kidney, the large intestine, and the spinal cord for (99m)Tc-BLMG, respectively. Scintigraphy and biodistributional studies performed on the experimental animals have shown that radiopharmaceutical potentials of these compounds are completely different. At the same time, uptake of the (99m)Tc-BLMG was found to be better than that of (99m)Tc-BLM.

Long-distance transport of pertechnetate in the moonflower ( Ipomoea alba)

The first research on the transport of metastable-technetium-99 ( 99mTc) in the form of pertechnetate ( TcO 4 − 99 m ) within plants suggested that TcO 4 − 99 m may be mobile in the phloem. In contrast, more recent evidence indicates the anion is transported in the xylem. Here we demonstrate that observations of 99mTc transport in the test subject of these initial investigations, the moonflower ( Ipomoea alba L.), are incompatible with phloem flow. Rather, the presence of only minute amounts of 99mTc in typical sinks for phloem solutes and 99mTc transport out of labeled leaves when shaded but not when illuminated strongly suggest that the radionuclide is transported in the xylem. The study increases confidence in the identification of TcO 4 − 99 m as a xylem mobile compound whose distribution in plants can be visualized using nuclear medicine scintigraphic imaging techniques.

Anterior chest wall examination reviewed

Anterior chest wall involvement is not infrequently observed within inflammatory arthropaties, particularly if one considers seronegative spondyloarthritides and SAPHO syndrome. Physical examination is unreliable and conventional X-rays analysis is an unsatisfactory tool during diagnostic work-up of this region. Scintigraphic techniques yield informations both on the activity and on the anatomical extent of the disease while computerized tomography visualize the elementary lesions, such as erosions, which characterize the process. Moreover, when available, magnetic resonance imaging couple the ability to finely visualize such lesions with the possibility to show early alterations and to characterize the "activity" of the disease, presenting itself as a powerful tool both for diagnosis and follow-up. This review briefly shows the applications of imaging techniques for the evaluation of the anterior chest wall focusing on what has been done in the SAPHO syndrome which can be considered prototypical for this regional involvement since it is the osteo-articular target mainly affected by the disease.

Nuclear Medicine Imaging of Infection in Cancer Patients (With Emphasis on FDG-PET)

Infections are a common cause of death and an even more common cause of morbidity in cancer patients. Timely and adequate diagnosis of infection is very important. This article provides clinicians as well as nuclear medicine specialists with a concise summary of the most important and widely available nuclear medicine imaging techniques for infectious and inflammatory diseases in cancer patients with an emphasis on fluorodeoxyglucose positron emission tomography (FDG-PET). ⁶⁷Ga-citrate has many unfavorable characteristics, and the development of newer radiopharmaceuticals has resulted in the replacement of ⁶⁷Ga-citrate scintigraphy by scintigraphy with labeled leukocytes or FDG-PET for the majority of conditions. The sensitivity of labeled leukocyte scintigraphy in non-neutropenic cancer patients is comparable with that in patients without malignancy. The specificity, however, is lower because of the uptake of labeled leukocytes in many primary tumors and metastases, most probably as a result of their inflammatory component. In addition, labeled leukocyte scintigraphy cannot be used for febrile neutropenia because of the inability to harvest sufficient peripheral leukocytes for in vitro labeling. FDG-PET has several advantages over these conventional scintigraphic techniques. FDG-PET has shown its usefulness in diagnosing septic thrombophlebitis in cancer patients. It has also been shown that imaging of infectious processes using FDG-PET is possible in patients with severe neutropenia. Although larger prospective studies examining the value of FDG-PET in cancer patients suspected of infection, especially in those with febrile neutropenia, are needed, FDG-PET appears to be the most promising scintigraphic technique for the diagnosis of infection in this patient group.

Scintigraphic Evaluation of Takotsubo Cardiomyopathy

The Takotsubo Cardiomyopathy (TC) also called broken heart syndrome, or stress-induced cardiomyopathy is characterized by the transient ballooning of the apex during systole as result of apical dyskinesia in conjunction with a compensatory hyperkinesia of the base of the left ventricle; in the absence of significant epicardial coronary artery dis- ease. We report a case of TC with the characteristic findings of apical dyskinesia and perfusion abnormalities on gated SPECT which was diagnosed in retrospect after coronary angiography and left ventriculography. This is followed by a brief review of the scintigraphic techniques that have been used in the evaluation of TC. As TC accounts for at least 1-2% of presentations of acute coronary syndromes, increased awareness on the part of interpreting physicians is required for earlier diagnosis in the subset of patients referred for myocardial perfusion imaging. TC can present with symptoms similar to CAD (Chest pain, shortness of breath, etc) in the presence of ECG changes and mild elevation of cardiac enzymes. It seems to be more frequent in women of post menopausal age (2) but the exact prevalence is unknown. Akashi and colleagues found that the prevalence of TC in their institution was around 2% (3) similar to what Bybee and co-workers re- ported (4). New cases of TC are reported every year around the world and nuclear medicine techniques have been used in evaluation of several of these cases. We present the follow- ing case in which gated SPECT contributed significantly to diagnosis followed by a brief review of the different scinti- graphic techniques that have been used in the evaluation of

Functional imaging of infection: conventional nuclear medicine agents and the expanding role of 18-F-FDG PET

A growing body of literature suggests that 18-fluorine fluorodeoxyglucose positron emission tomography ((18)F-FDG PET), particularly when combined with CT, is a useful tool for the detection of infectious and inflammatory disease processes. This article will briefly review the data to date on the use of FDG PET in diagnosing musculoskeletal infections and fever of unknown origin, comparing it to conventional scintigraphic techniques in both adults and, when available, in children.

T2-Cardiac Magnetic Resonance

The region of myocardium hypoperfused during ischemia, also known as the area at risk (AAR), has sought our attention since the earliest understandings of the wavefront of progressive myocardial infarction (MI) due to acute coronary syndromes (ACS).1 Edema took center stage as evidence accrued that cardiomyocytes take on water in the setting of ischemia and reperfusion2; this, in turn, led to the notion that the myocyte's survival was determined by whether sarcolemmal membrane resistance was exceeded.3 The development of nuclear scintigraphic techniques afforded demonstration of the perfusion deficit in vivo at the time of presentation. Comparison with histology in a number of autopsy hearts confirmed that in many patients, a large scintigraphic defect often was present despite a small area of irreversibly injured or infarcted myocardium; that is, there appeared to be myocardium at risk of irreversible injury but potentially salvageable.4 The authors presciently concluded that this group of patients had the “greatest promise for intervention.” Articles see p 210 and 228 Fast forward to the present era of rapid mechanical revascularization coupled with a host of pharmacological maneuvers to restore blood flow, and what do we find: reduced but still significant morbidity (≥3.4% patients per year develop heart failure after MI5), mortality (≈20% of men and women aged >40 years die in the first year after initial MI6), and cost of subsequent care (≈$32,000 per patient is spent in the first year after MI7). Although increased infarct size consistently portends worse outcomes,8,9 it would make sense to develop interventions that reduce ultimate infarct size while myocardium is still salvageable; this, in turn, requires reliable …

(iii) The basic science of nuclear medicine

Abstract Functional imaging techniques in nuclear medicine provide crucial diagnostic information in a variety of clinical settings that are encountered regularly in orthopaedic practice. It is important that the orthopaedic surgeon is aware of the modalities on offer and appreciates the relative strengths and limitations of these techniques. This article will describe the physical principles underlying nuclear medicine imaging with single-photon and positron-emitting radiotracers. It will then go on to illustrate the clinical applications of these techniques as applied to pathological conditions of the bone, with particular emphasis on bone scintigraphy and hybrid imaging techniques, such as single-photon emission computed tomography/computed tomography (SPECT/CT) and positron emission tomography/computed tomography (PET/CT).

Scintigraphic Techniques for Early Detection of Cancer Treatment–Induced Cardiotoxicity

New antitumor agents have resulted in significant survival benefits for cancer patients. However, several agents may have serious cardiovascular side effects. Left ventricular ejection fraction measurement by (99m)Tc multigated radionuclide angiography is regarded as the gold standard to measure cardiotoxicity in adult patients. It identifies left ventricular dysfunction with high reproducibility and low interobserver variability. A decrease in left ventricular ejection fraction, however, is a relatively late manifestation of myocardial damage. Nuclear cardiologic techniques that visualize pathophysiologic processes at the tissue level could detect myocardial injury at an earlier stage. These techniques may give the opportunity for timely intervention to prevent further damage and could provide insights into the mechanisms and pathophysiology of cardiotoxicity caused by anticancer agents. This review provides an overview of past, current, and promising newly developed radiopharmaceuticals and describes the role and recent advances of scintigraphic techniques to measure cardiotoxicity. Both first-order functional imaging techniques (visualizing mechanical [pump] function), such as (99m)Tc multigated radionuclide angiography and (99m)Tc gated blood-pool SPECT, and third-order functional imaging techniques (visualizing pathophysiologic and neurophysiologic processes at the tissue level) are discussed. Third-order functional imaging techniques comprise (123)I-metaiodobenzylguanidine scintigraphy, which images the efferent sympathetic nervous innervations; sympathetic neuronal PET, with its wide range of tracers; (111)In-antimyosin, which is a specific marker for myocardial cell injury and necrosis; (99m)Tc-annexin V scintigraphy, which visualizes apoptosis and cell death; fatty-acid-use scintigraphy, which visualizes the storage of free fatty acids in the lipid pool of the cytosol (which can be impaired by cardiotoxic agents); and (111)In-trastuzumab imaging, to study trastuzumab targeting to the myocardium. To define the prognostic importance and clinical value of each of these functional imaging techniques, prospective clinical trials are warranted.

Design and evaluation of baicalin-containing in situ pH-triggered gelling system for sustained ophthalmic drug delivery

Baicalin has been reported to have anti-inflammatory and anti-cataract effects on eye tissues, but it has a low bioavailability partly due to its poor stability of baicalin, the special anatomic structure and efficient protective mechanism of eyes. The aim of this study was to investigate the correlation between the stability of baicalin and in situ pH-triggered gelling system. Carbopol ® 974P (0.3%, w/v) was used as the gelling agent combined with hydroxypropylmethylcellulose E4M (0.6%, w/v) which acted as a viscosity enhancing agent. In vitro and in vivo evaluations were performed using several techniques, namely confocal scanning light microscopy analysis, rheometry, Gamma scintigraphic technique and microdialysis method. The rheological behavior showed a significant enhancement in gel strength under physiological conditions, and the formulation provided sustained release of the drug over an 8-h period. In elimination studies, the radioactivity of formulation was always higher than that of the control solution. Additionally, the AUC and C max values were 6.1-fold and 3.6-fold higher than those of the control solution, respectively. The results demonstrated that an in situ pH-triggered gelling system have better ability to keep baicalin stable and retain drug release than marketed baicalin eye drops to enhance the ocular bioavailability.

Wertigkeit der SPECT/CT für die nuklearmedizinische Entzündungsdiagnostik

Even today infection remains a significant concern, and the diagnosis and localization of infectious foci is an important health issue. As an established infection-imaging modality, nuclear medicine plays a vital health-care role in the diagnosis and subsequent effective treatment of this condition. Several techniques in nuclear medicine significantly aid infection diagnosis, including triple-phase bone scanning, 18 F-FDG-PET and imaging with 111 In-oxine-, 99m Tc-HMPAO-labeled leukocytes. Each radiopharmaceutical has specific advantages and disadvantages that makes it suitable to diagnose different infectious processes (e. g., soft-tissue sepsis, inflammatory bowel disease, osteomyelitis, occult fever, fever of unknown origin, and infections commonly found in immuno-compromised patients). However, their clinical applications may be limited by the relatively low spatial resolution and the lack of anatomic landmarks of a highly specific tracer with only scarce background uptake to use as a framework for orientation. Anatomic imaging modalities such as CT provide a high-quality assessment of structural abnormalities related to infection, but these structural abnormalities may be unspecific. Furthermore, to detect infection before anatomical changes are present, functional imaging could have some advantages over anatomical imaging. Scintigraphic studies have demonstrated high sensitivity and specificity to an infectious process. Diagnosis and precise delineation of infection may be challenging in certain clinical scenarios, rendering decisions concerning further patient management difficult. The SPECT/CT-technology combines the acquisition of SPECT and CT data with the same imaging device enabling perfect overlay of anatomical and functional images. SPECT/CT imaging data has been shown to be beneficial for many clinical settings such as indeterminate findings in bone scintigraphy, orthopaedic disorders, endocrine, and neuroendocrine tumors. Therefore, the complementary use of scintigraphic and anatomic imaging modalities is expected to overcome many of the limitations also in the assessment of infection. This article discusses current scintigraphic techniques of infection imaging with particular attention to the diagnostic value of SPECT/CT.

Review article: methods of measuring gastric acid secretion

Gastric acid has an important pathophysiological role in human beings. Numerous methods have been evaluated over the years in an attempt to measure gastric acid and stomach acidity, to study the role of gastric acid in gastrointestinal diseases in humans and to evaluate the effects of acid suppressing drugs. To review methods that have been used to measure gastric acid and gastric acidity. Searches of the electronic databases PUBMED, MEDLINE and EMBASE, were performed with articles restricted to English language and human subjects. References were also identified from the bibliographies of selected articles. Methods for measuring gastric acid include both invasive and non-invasive techniques. Invasive tests include the conventional gastric acid aspiration tests, gastric pH measurement techniques and endoscopic methods. Non-invasive methods use urinary analysis, breath analysis, serum pepsinogens assay, scintigraphic techniques, impedence tomography and alkaline tide for measurement of gastric acid. Several methods of measuring gastric acid exist. Invasive tube tests are uncomfortable and time consuming, whereas most of the non-invasive methods are at best semiquantitative and useful in detecting low or absent acid secretion. Further attempts to explore new methods for measuring gastric acid are therefore warranted.

Detection of Pulmonary Embolism with 99mTc-Labeled F(ab)2 Fragment of Anti-P-Selectin Monoclonal Antibody in Dogs

Pulmonary embolism is a common and potentially life-threatening condition, and its correct diagnosis is highly desirable before anticoagulant therapy is initiated. However, the safe and accurate diagnosis of acute pulmonary embolism remains a challenge. Single photon emission computed tomography (SPECT) is a highly sensitive scintigraphic imaging technique. Pulmonary embolism can be detected by SPECT with (99m)Tc-labeled imaging agents that bind to components present predominantly on thromboemboli. P-selectin is an adhesion glycoprotein that is expressed in platelets and endothelial cells. P-selectin on activated platelets is a suitable biomarker of the active thrombus process. The objective of this study was to evaluate (99m)Tc-labeled F(ab)(2) fragment of anti-P-selectin monoclonal antibody SZ51, (99m)Tc-SZ51-F(ab)(2), for imaging pulmonary embolism in beagle canines. SZ51 was digested to F(ab)(2) fragment, named SZ51-F(ab)(2), and its specific binding to P-selectin on either human or canine platelets was verified by flow cytometry assay. In each dog, an 18-gauge catheter was inserted into left or right pulmonary artery, and a two-stranded spiral stainless-steel coil (20 mm) was inserted through catheter. At 30 min after coil placement, X-ray angiography was performed to document the pulmonary embolism and the locations of the coil. After intravenous injection of (99m)Tc-SZ51-F(ab)(2), experimental thrombi in dogs could be consistently visualized for 2-3 hours by SPECT. Pulmonary embolism showed higher uptake of (99m)Tc-SZ51-F(ab)(2). The present study suggests that (99m)Tc-SZ51-F(ab)(2) may be a promising agent for detecting pulmonary embolism.

Imaging of Inflammation by PET, Conventional Scintigraphy, and Other Imaging Techniques

Nuclear medicine imaging procedures play an important role in the assessment of inflammatory diseases. With the advent of 3-dimensional anatomic imaging, there has been a tendency to replace traditional planar scintigraphy by CT or MRI. Furthermore, scintigraphic techniques may have to be combined with other imaging modalities to achieve high sensitivity and specificity, and some may require time-consuming labeling procedures. On the other hand, new developments such as combined SPECT/CT increase the diagnostic power of scintigraphy. Also, the advent of PET had a considerable impact on the use of nuclear medicine imaging techniques. In this review, we aim to provide nuclear medicine specialists and clinicians with the relevant information on rational and efficient use of nuclear medicine imaging techniques in the assessment of patients with osteomyelitis, infected vascular prostheses, metastatic infectious disease, rheumatoid arthritis, vasculitis, inflammatory bowel disease, sarcoidosis, and fever of unknown origin.

Skeletal Scintigraphy in Pediatric Sports Medicine

Athletes can have pain derived from fractures or alternate pathology. Skeletal scintigraphy may detect abnormalities before anatomic imaging and provides a practical tool for whole-body imaging. However, study interpretation in children can be challenging. This pictorial essay describes a technique for pediatric skeletal scintigraphy and reviews findings commonly encountered in athletes. Skeletal scintigraphy complements anatomic findings in pediatric athletes. Familiarity with imaging technique and study interpretation can improve diagnosis.

Nanostructured lipid carrier (NLC) coated with Chitosan Oligosaccharides and its potential use in ocular drug delivery system

The objective of the present investigation was to explore the potential of the Chitosan Oligosaccharides (COS)-coated NLC (nanostructured lipid carrier) for ocular drug delivery. NLC loaded with flurbiprofen was prepared by melt-ultrasonic method and then coated with COS with a molecular weight of 3000–6000kDa. After coating, the particles reflected spherical morphology with smooth surface under transmission electron microscope (TEM) analysis and a changed zeta potential from −0.446mV to +20.7mV. The ocular bioadhesion property was evaluated by Gamma scintigraphic technique, revealing that the clearance of the formulations labeled with radioactive 99mTc-DTPA was significantly delayed in the presence of COS, and the AUC of the COS-coated formulation had a 7.7-fold increase comparing with non-coated ones. Additionally, enhanced transcorneal penetration was achieved by using the COS coating with a corresponding apparent permeability coefficients (Papp) which had a 2.4-fold increase comparing with the reference. Consequently, COS coating modified the properties of NLCs and presented a series of notable advantages in ophthalmic application.

Scintigraphy vs. mechanical magnetogastrography: gastric emptying analysis

Scintigraphy technique is considered the gold standard for gastric emptying evaluations. Lately mechanical magnetogastrography (MMG) technique has emerged as an alternative for these assessments. This study presents the determination of reference values for MMG in order to validate this novel technique in gastric emptying measurements. Both methodologies were used in young and healthy subjects provided with a solid test meal. The measurements were performed with 2 days of difference. Bland-Altman analysis of the data was performed to conclude about the feasibility of MMG as a good alternative test for gastric emptying assessments. Using MMG, an average of the gastric emptying half-time of 57.6 +/- 25.8 min was obtained, whereas the same parameter obtained by scintigraphy was 52.2 +/- 12.9 min. In conclusion, the use of MMG technique is in concordance with the results using the gold standard technique for gastric emptying measurements.

Szintigrafie zur Bestimmung der Magenentleerungszeit beim Kleintier

Eine verzögerte Magenentleerung ist als primäre Erkrankung sowie als Sekundärerscheinung bei unterschiedlichen Krankheitsprozessen bei Hund und Katze bekannt. Dabei ist die Diagnose einer Magenentleerungsstörung in der Veterinärmedizin schwierig; die szintigrafische Untersuchung gilt jedoch als Goldstandardmethode. Allerdings ist die Bestimmung von Referenzwerten nicht unproblematisch und die Signifikanz alimentärer sowie physiologischer Einflüsse, Rasse oder Gewicht ungeklärt. Weiterhin ist der routinemäßige Einsatz durch gesetzliche Regularien, die Verfügbarkeit der Methode sowie Probleme in der Interpretation eingeschränkt. Dieser Artikel soll einen Überblick über die bisher beim Kleintier angewandten szintigrafischen Techniken zur Bestimmung der Magenentleerungszeit geben und Vor- und Nachteile der Methode aufzeigen.

Avaliação cintilográfica de diferentes dosagens de Tecnécio-99m na padronização da perfusão pulmonar em cães da raça Rottweiller

A avaliação da função pulmonar em cães pode ser obtida mediante exames cintilográficos, os quais incluem a injeção de radiofármacos, seguida de radiografias. Neste estudo, foram utilizados 10 cães machos hígidos da raça Rottweiler e radiograficamente normais e soronegativos para dirofilariose, com administração de doses variadas de macroagregado de albumina sérica humana marcados com tecnécio-99m ([99mTc](MAA)). Os resultados foram avaliados qualitativa e quantitativamente, considerando o índice de perfusão pulmonar e sua homogeneidade, sendo dessa maneira visualizado um aumento na homogeneidade da imagem diretamente relacionado ao número de partículas de MAA injetado. Este estudo define os critérios de normalidade e de dosagem na perfusão pulmonar em cães hígidos da raça Rottweiller estabelecidos com a técnica de cintilografia.

Autotransplantation of cryopreserved minor salivary glands: A new approach for management of radiation-induced xerostomia

To date, it still is impossible to successfully prevent radiation-induced xerostomia. Therefore, further research, particularly regarding treatment, is urgently warranted. Lower labial mucosa with its submucosal minor salivary glands (MSGs) of approximately 2.5 x 3 cm can be prepared by means of a surgical knife or Ellman Surgitron high-frequency/low-temperature radiosurgical device. Also we can consider area of the palatine fovea to find and remove MSGs. We can find locations containing more MSGs via scintigraphy techniques and positron emission tomography. Removing of MSGs can be done 1-2 weeks before start of radiotherapy. Subsequently the MSGs containing complex graft should be cryopreserved via liquid nitrogen for long-term storage. Autotransplantation surgery will be carried out 2-3 months after radiotherapy. The frozen tissue could be thawed rapidly in a 37 degrees C water bath for 2-3 min. Host site should be as far as possible to the radiation zone and has a good blood supply. Hyperbaric oxygen therapy (30 treatment sessions before and 10 sessions after re-implantation) is strongly recommended. An aggressive short or medium-term antibiotic treatment will necessary to avoid infection. Immunosuppressive treatment will not require. The main criticism with this hypothesis is viability and usefulness of MSGs containing graft, after being frozen and subsequently thawed.