Nuclear Medicine Diagnosis Research Articles

Evaluation of syringe shield effectiveness in handling radiopharmaceuticals

The purpose of this study was to evaluate the effectiveness of the radiation shield of radionuclide syringes and the personal dose equivalent by performing a simulation of radionuclides used in nuclear medicine diagnosis. In order to evaluate the dose depending on the distance between the radiation source and the ICRU sphere against the thickness of the shielding device, the distance at which a nuclear medicine worker may inadvertently come into contact with radiation from the radiation source was set at 0 cm to 30 cm according to the thickness of the shield, thus fixing the ICRU sphere. For a dose evaluation, Hp(10), Hp(3), and Hp(0.07) measurable in specific depth of the ICRU were evaluated. It was found that a dose measured on skin surface of nuclear medicine workers was relatively higher, that the dose varied in relation to the thickness of the radiation shield, and that the shielding effect decreased for some radiation sources such as 67Ga and 111In. It proved necessary to increase thickness of shielding device to the radiation sources such as 67Ga and 111In. It is also considered that a study of proper shielding thickness will be needed in future.

Nuclear Medicine in diagnosis of breast cancer

Breast cancer is the most common malignancy among women worldwide, creating a significant need for improved imaging modalities. The advantage of molecular imaging over other imaging methods, as confirmed by clinical experience, is the ability of providing functional information. This process is achieved by labeling a biomarker with an isotope of choice. Therefore imaging methods such as scintimammography (SM), (18)F-fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography ((18)F-FDG PET/CT), positron emission mammography (PEM), lymphoscintigraphy, have proved to be extremely efficient compared to morphological imaging of anatomical lesions, as they allow the diagnosis, staging, assessment of therapeutic efficacy and patient monitoring to contribute as much as possible to improve the prognosis. The development of new radiopharmaceuticals in PET imaging, allowing the visualization and quantification of biomarkers, such as (18)F-fluoro-17-estradiol, which is bound by the estrogen receptors (ER), (18)F-fluoro-l-thymidine (FLT) which is a marker of cell proliferation, (18)F-fluoromisonidazole (FISO) a marker of tumor hypoxia and angiogenesis markers such as (18)F-fluoroazomycinarabinoside, may give us additional information on the characteristics and progress of the disease and allow the conduct of targeted therapy. Radioimmunoassay (RIA) using monoclonal antibodies in order to recognize serum markers such as CA 15.3, CEA, cytokeratins TPA, TPS and Cyfra 21.1, are necessary in the diagnosis of a possible recurrence of the disease as well as the degree of response to treatment. Modern research focusing on the development of new specific functional breast imaging methods improves diagnostic and therapeutic management of patients with breast cancer.

Activity thresholds for patient instruction and release for positron emission tomography radionuclides.

The use of unconventional or novel radionuclides for positron emission tomography (PET) is becoming more prevalent in both nuclear medicine diagnosis and therapy. Many of these radionuclides are produced in cyclotrons or are further eluted from generators. Although half-lives from many of these unconventional PET radionuclides are considered relatively short (minutes to hours, but some are days) and the intent of their use is often as a diagnostic imaging agent, patient release criteria and patient radiation safety instruction regulatory requirements are based on estimated dose to a member of the public. This paper reviews a method referenced routinely for patient release criteria as found in U.S. Nuclear Regulatory Commission guidance, estimates fundamental quantities used in the method, compares estimated quantities with the published literature, and calculates release and patient radiation safety instruction criteria for several novel PET radionuclides used in nuclear medicine. It should be recognized that some quantities of novel PET radionuclides in use today reach the threshold for patient safety instruction using conservative model procedures for patient release.

Generation of Radioisotopes with Accelerator Neutrons by Deuterons

A new system proposed for the generation of radioisotopes with accelerator neutrons by deuterons (GRAND) is described by mainly discussing the production of 99Mo used for nuclear medicine diagnosis. A prototype facility of this system consists of a cyclotron to produce intense accelerator neutrons from the natC(\(d\),\(n\)) reaction with 40 MeV 2 mA deuteron beams, and a sublimation system to separate 99mTc from an irradiated 100MoO3 sample. About 8.1 TBq/week of 99Mo is produced by repeating irradiation on an enriched 100Mo sample (251 g) with accelerator neutrons for two days three times. It meets about 10% of the 99Mo demand in Japan. The characteristic feature of the system lies in its capability to reliably produce a wide variety of high-quality, carrier-free, carrier-added radioisotopes with a minimum level of radioactive waste without using uranium. The system is compact in size, and easy to operate; therefore it could be used worldwide to produce radioisotopes for medical, research, and industrial...

APPLICATION OF TECHNETIUM AND RHENIUM IN NUCLEAR MEDICINE

Technetium and Rhenium are the two lower elements in the manganese triad. Whereas rhenium is known as an important part of high resistance alloys, technetium is mostly known as a cumbersome product of nuclear fission. It is less known that its metastable isotope 99mTc is of utmost importance in nuclear medicine diagnosis. The technical application of elemental rhenium is currently complemented by investigations of its isotope 188Re , which could play a central role in the future for internal, targeted radiotherapy. This article will briefly describe the basic principles behind diagnostic methods with radionuclides for molecular imaging, review the 99mTc -based radiopharmaceuticals currently in clinical routine and focus on the chemical challenges and current developments towards improved, radiolabeled compounds for diagnosis and therapy in nuclear medicine.

Applicability of radioactive 99mTc-O4− magnetic fluid to nuclear medicine

Magnetite nanoparticles were synthesized with solution of ferrous and ferric chlorides and ammonia water by sonochemical method. The hydrophilically radioactive magnetic fluids were prepared by labeling technetium pertechnetate (99mTc-O4−) and then adsorbing alginic acid on the magnetite particles. In order to measure some properties of the dispersed particles, the magnetic fluids were freezed down to -70 oC, and were dried in vacuum. The total size of the particles was about 15 nm with the core diameter of 12 nm and their superparamagnetic saturation magnetization was 63 emu/g for the core-shell of Fe3O4/Algin and 52 emu/g for that of Fe3O4/99mTc-O4−/Algin. The labeling of radioactive 99mTc-O4− to the magnetite particles was efficient to about 70 %. The fluid of magnetic particles on which the radioisotopic substance is labeled with such an efficiency level may be applied as a tracer for diagnosis in nuclear medicine.

Limitation of the long-lived 121Te contaminant in production of 123I through the 124Xe(p,x) route

The 13.2 h half-life radioisotope (123)I is widely used in clinical nuclear medicine diagnosis. At present it is mostly produced in nca form by proton irradiation of highly enriched (124)Xe in dedicated gas target set-ups and relying on the decay chain (123)Cs-(123)Xe-(123)I. Depending on the irradiation conditions contamination with long-lived (121)Te, a daughter product of the co-produced rather short lived (121)I, occurs and can limit the useful shelf life of the (123)I solution. Excitation function of the (124)Xe(p,α)(121)I, (124)Xe(p,2n)(123)Cs and (124)Xe(p,2p)(123)Xe reactions are measured up to 35 MeV using the stacked gas cell technique and high-resolution γ-ray spectrometry. The experimental data were compared with the earlier literature values, with new results of the ALICE-IPPE and EMPIRE-II codes and with the data taken from the TENDL-2009 database. Existing discrepancies in cross-section data are largely solved and new recommended values are proposed. From fits to the new excitation curves integral (123)I batch yields and (121)Te contaminations for realistic production conditions are derived. Optimization of irradiation and cooling times and energy degradation in the target can strongly influence the contamination level.

Synthesis, quality control and dosimetry of the radiopharmaceutical 18F-sodium fluoride produced at the Center for Development of Nuclear Technology - CDTN

18F-Sodium fluoride (Na18F) is a radiopharmaceutical used for diagnosis in nuclear medicine by positron emission tomography (PET) imaging. Bone scintigraphy is normally performed using 99mTc-MDP. However, 18F PET scans promise high quality imaging with increased resolution and improved sensitivity and specificity. In order to make available a tool for more specific studies of tumors and non-oncological diseases of bone tissue, the UPPR/CDTN team undertook the production and quality control of Na18F injectable solution with the physical-chemical, microbiological and biological characteristics recommended in the U.S. Pharmacopeia. Na18F radiochemical purity was 96.7 ± 1.3 %, with Rf= 0.026 ± 0.006. The product presented a pH of 5.3 ± 0.6, half life of 109.0 ± 0.8 minutes, endotoxin limit < 5.0 EU.mL-1 and no microbial contaminants. The biodistribution of Na18F was similar to that described in the literature, with a clearance of 0.19 mL.min-1 and distribution volume of 18.76 mL. The highest bone concentration (5.0 ± 0.5 %ID.g-1) was observed 20 minutes after injection. Na18F produced at the UPPR presented all the quality assurance requirements of the U.S. Pharmacopeia and can be safely used for clinical bone imaging.

Diagnosis of Prosthetic Aortic Valve Endocarditis With Gallium-67 Citrate Single-Photon Emission Computed Tomography/Computed Tomography Hybrid Imaging Using Software Registration

Prosthetic valve endocarditis can be challenging to diagnose and is associated with high mortality rates even if recognized and managed early. We present a case of staphylococcal sepsis soon after aortic valve surgery and permanent pacemaker implantation for which conventional investigation with echocardiography and computed tomography (CT) failed to identify an infective focus. Subsequent gallium–single-photon emission CT (67Ga-SPECT) imaging with software registration of the SPECT data helped to correctly identify the prosthetic aortic value as the source of sepsis, with resolution of changes on subsequent imaging. A 70-year-old woman underwent bioprosthetic aortic valve replacement and coronary artery bypass grafting for symptomatic severe aortic stenosis and significant 2-vessel coronary disease. Her postoperative course was complicated by significant bradycardia necessitating dual-chamber permanent pacemaker implantation. She presented 3 months after surgery in a confused state, with low-grade pyrexia. The examination identified a soft systolic aortic murmur but no diastolic component, normal breath sounds, absence of cutaneous markers of endocarditis, and no evidence of …

Particle size analysis: 90Y and 99mTc‐labelled colloids

Colloidal particle size is an important characteristic to consider when choosing a radiopharmaceutical for diagnosis and therapeutic purposes in nuclear medicine. Photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM) were used to determine the particle-size distribution of (90)Y- and (99m)Tc-labelled antimony trisulfide (Sb(2)S(3)) and tin colloids (Sn-colloid). (90)Y-Sb(2)S(3) and (99m)Tc-Sb(2)S(3) were found to have a diameter of 28.92 +/- 0.14 and 35.61 +/- 0.11 nm, respectively, by PCS. By TEM, (90)Y-Sb(2)S(3) particles were measured to be 14.33 +/- 0.09 nm. (90)Y-labelled Sn colloid were found to exist with a d(v(max1)) of 805 nm and a d(v(max2)) of 2590 nm, by PCS, whereas (99m)Tc-Sn colloid was shown to have more than 80% of radioactive particles of approximately 910 nm by PCS. For (90)Y-labelled Sb(2)S(3) and Sn colloid, a comparison of TEM and PCS indicates that these techniques found significantly different mean diameters. TEM has an excellent resolution necessary for radiocolloid particle-sizing analysis, and it is a desirable size-measuring technique because it is more reliable than PCS.

Nuclear medicine diagnosis of motility disorders of the esophagus

Drug Prescribing for Patients with Chronic Kidney Disease in General Practice: a Cross-Sectional Study

Quality audit programme for 99mTc and 131I radioactivity measurements with radionuclide calibrators

The use of radiopharmaceuticals in nuclear medicine for diagnosis and therapy has increased over the years with 99mTc and 131I being most widely used. Quality audit programmes for radioactivity measurements of 131I have been ongoing and the 12th audit was recently conducted among seventy nuclear medicine centres (NMC) in India. An audit for the activity measurements of 99mTc was conducted for the first time among ten NMCs in Mumbai, India. These programmes for radioactivity measurements have become very important to establish traceability of measurements to national and international standards and ensure accurate calibration of radionuclide calibrators. The results of both the audits are very encouraging. Ninety-four percent of the NMCs for 131I activity measurements were within a window of ±10% and for 99mTc one NMC was deviating more than ±10%. The methodology adopted for the audit and results are discussed in detail in this paper.

Preparações radiofarmacêuticas e suas aplicações

Radiopharmaceuticals are substances without pharmacological activity that are used in Nuclear Medicine for diagnosis and therapy for several diseases. Diagnosis radiopharmaceuticals generally emit g radiation or positrons (b+), because their decay originates penetrating electromagnetic radiation that can cross the tissues and be externally detected. Therapeutic radiopharmaceuticals must include in their composition ionized particles emission nucleus (a, b- or Auger electrons), since their action is based in selective tissue destruction. There are two main methods for image acquisition: SPECT (Single Photon Emission Computerized Tomography) that uses g emission radionuclides (99mTc, 123I, 67Ga, 201Tl) and PET (Positron Emission Tomography) that uses positron emission radionuclides like 11C, 13N, 15O, 18F. Radiopharmaceuticals can be classified into perfusion radiopharmaceuticals (first generation) or specific radiopharmaceuticals (second generation). Perfusion radiopharmaceuticals are transported in the blood e reach the target organ in the direct proportion of the blood stream. Specific radiopharmaceuticals contain a biologically active molecule that binds to cellular receptors that must remain biospecific after binding to the radiopharmaceutical. For this type of radiopharmaceuticals, tissue or organ uptake is determined by the biomolecule capacity of recognizing receptors in those biological structures. Radiopharmaceuticals are produced ready to use, in cold kits or in autologal preparations. According to the preparation type there is a different quality control procedure. Most of the radiopharmaceuticals used nowadays are of the perfusion type. Research focus in the development of specific radiopharmaceuticals that can provide information, at the molecular level, of biochemical alterations associated to different pathologies.

Determination of 99Mo contamination in a nuclear medicine patient submitted to a diagnostic procedure with 99mTc

99mTc is a radionuclide widely used for imaging diagnosis in nuclear medicine. In Brazil it is obtained by elution from 99Mo-99mTc generators supplied by the Nuclear Energy Research Institute (IPEN). The elution is carried out in radiopharmacy laboratories located in hospitals and clinics. Depending of the quality of the generator and conditions of use during the elution process, 99Mo can be extracted from the column of the generator, becoming a radionuclidic impurity of the eluate used for the obtention of the radiopharmaceutical to be administered to the patient. 99Mo emits high-energy photons and beta particles and its presence degrades the quality of the image and unnecessarily increases the radiation dose delivered to the patient. An in-vivo measurement technique was developed to verify the occurrence of internal contamination by 99Mo in nuclear medicine patients. Direct measurements were made in a volunteer who underwent myocardial scintigraphy with 99mTc-sestamibi. The results indicated the presence of internal contamination of the patien by 99Mot. The activity was tracked for several days, and an assessment of the radiation dose from the contaminant 99Mo was made.

Radiopharmaceuticals: From Molecular Imaging to Targeted Radionuclide Therapy

The research and development of smart radiodrugs is the goal of the Center of Radiopharmaceutical Science of ETH, PSI, and USZ. Positron Emission Tomography (PET) allows the non-invasive visualization of biochemical processes within the body. Radiolabeled PET-tracers allow the study of neurophysiological diseases like Alzheimer, Parkinson's disease or the imaging of metastatic tumors. PET-techniques are nowadays an important part of routine nuclear medicine diagnosis. Tumor-cell targeting biomolecules (e.g. antibodies or peptides) coupled to therapeutic radionuclides can sterilize the malignant cells while sparing healthy tissue. This so-called targeted radionuclide therapy has made tremendous progress in the recent years and the first approved radiotherapeutics are available for clinical use.

Synthesis of a technetium‐99m labelled L‐tyrosine derivative with the fac‐99mTc(I)(CO)3‐core using a simple kit‐procedure

AbstractThe synthesis of a novel technetium‐99m labelled derivative of L‐tyrosine as a potential tumour imaging agent for nuclear medicine diagnosis is reported. The synthesis involved the labelling precursor fac‐[99mTc(OH2)(CO)3]+ which was synthesized using the commercially available Isolink®‐labelling kit and the tyrosine derivative O‐(N,N‐bis(carboxymethyl)aminoethyl)‐L‐tyrosine trifluoroacetate. The labelled compound O‐(99mTc(I)‐tricarbonyl‐N,N‐bis(carboxymethyl)aminoethyl)‐L‐tyrosine was obtained in a radiochemical yield of 70–80% within 60 min with a radiochemical purity greater than 98% without any HPLC purification step. Purification was achieved merely by solid phase extraction. Chemical as well as chiral purity was determined using gradient‐ and chiral HPLC. Copyright © 2004 John Wiley & Sons, Ltd.

Complementary alternative medicine and nuclear medicine therapy and diagnosis

Complementary alternative medicine and nuclear medicine therapy and diagnosis

Parameter estimation in Bayesian reconstruction of SPECT images: An aid in nuclear medicine diagnosis

AbstractDespite the adequacy of Bayesian methods to reconstruct nuclear medicine SPECT (single‐photon emission computed tomography) images, they are rarely used in everyday medical practice. This is primarily because of their computational cost and the need to appropriately select the prior model hyperparameters. We propose a simple procedure for the estimation of these hyperparameters and the reconstruction of the original image and test the procedure on both synthetic and real SPECT images. The experimental results demonstrate that the proposed hyperparameter estimation method produces satisfactory reconstructions. Although we have used generalized Gaussian Markov random fields (GGMRF) as prior models, the proposed estimation method can be applied to any priors with convex potential and tractable partition function with respect to the scale hyperparameter. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 21–27, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20003

1036 Nuclear medicine in diagnosis of skeletal invasion by Hodgkin's disease

1036 Nuclear medicine in diagnosis of skeletal invasion by Hodgkin's disease

Preferential uptake of zinc, manganese, and rubidium in rat brain tumor

The search for radionuclides that can be an index of viability in proliferating cells is important for nuclear medicine diagnosis of brain tumors. On the basis of the finding that 65Zn is preferentially taken up in rat brain tumors, the uptake of various radionuclides was examined in rat brain tumor by using the multitracer technique. Male Fisher rats were intrahippocampally injected with C6 glioma cells. Fourteen days after implantation, the radioactive multitracer solution was injected into the tail vein of tumor-bearing rats. One hour after intravenous injection, the uptake of 65Zn, 83Rb and 54Mn was relatively high in C6 glioma of 15 radionuclides detected, and was much higher than in other brain regions and in the blood. It is likely that rubidium and manganese, in addition to zinc, are preferentially taken up by tumors in the brain.