Open letter to journal editors on : International Consensus Radiochemistry Nomenclature Guidelines
In previous years FDG-PET/CT has acquired a significant role in radiotherapy treatment of head and neck (H&N) disease. This study focuses on the added value of PET/CT with respect to conventional CT in terms of target delineation and dosimetric implications. Materials and Methods. Thirty patients with H&N cancer who underwent FDG-PET/CT examination were analysed retrospectively. Gross tumour volumes were first delineated on CT (CT-GTVs) blinded to PET data and successively on the co-registered PET/CT (PET-GTVs). Both volumes were visible on the fused images. CT and PET/CT volumes were compared. The aim was to understand if tumour regions might be omitted if PET data is not considered in the planning stage. A simulation of a treatment plan was developed based on the CT-GTVs and the dosimetric coverage of PEThighlighted tumour regions were evaluated. Results. The mismatching fraction between PET and CT volumes (56%) indicates that PET significantly changes the GTV definition. A simulation of a CT-based treatment plan resulted in 23% of the analysed patients having important underdosages in PET volumes (primary tumour) in the range (-96.5% to -27.4%) while the lymph nodes were underdosaged in the range (-99.1% to -25.1%) for 33% of patients. Conclusions. In radiotherapy treatment of H&N disease, PET/CT provides a better target definition and prevents exclusion of pathologic regions. In the population that we analysed here, PET data integrating other conventional diagnostic modalities such as CE-CT, MRI or US avoids significant underdosages of the tumour tissue in 37% of patients.
The movement of physiologic nucleosides and nucleoside analogue drugs across biological membranes is mediated by nucleoside transport proteins.In cancer, nucleoside transporters have an important role in maintaining the hyperproliferative state of tumours and are important targets for diagnostic and therapeutic agents in the detection, treatment and monitoring of cancers.The nucleoside-based probe 3ꞌ-deoxy-3ꞌ-[ 18 F]fluoro-Lthymidine ([ 18 F]FLT) has been developed for PET imaging of proliferating cancer cells, which is less prone than 2deoxy-2-[ 18 F]fluoro-D-glucose ([ 18 F]FDG) to non-specific effects.[ 18 F]FLT enters proliferating cells through nucleoside transporters, then becomes phosphorylated and blocks DNA synthesis, whilst also becoming trapped inside the cell.Practicable and automated chemical syntheses of [ 18 F]FLT have been developed, for which the most widely used radiolabelling precursor is the thymidine derivative 3-N-boc-5ꞌ-O-dimethoxytrityl-3ꞌ-O-nosylthymidine.[ 18 F]FLT PET imaging has undergone feasibility studies and has been assessed in pre-clinical and clinical studies for the detection and diagnosis of cancers and in monitoring their response to treatments.The roles of nucleoside transporters, especially ENT1, in the cellular uptake of [ 18 F]FLT have been investigated.
Aim of this work is the calibration of a SPECT/CT scanner (SYMBIA T2 -SIEMENS) for activity quantification in 99m Tc-macroaggregated albumin ( 99m Tc-MAA) clinical acquisitions used for radiation dosimetry before radioembolization.Materials and methods: SPECT/CT calibration was performed using the methodology proposed by Zeintl et al [1].A calibration factor converting cps (counts per second) to activity was determined using a uniform radioactive solution in a cylindrical water phantom.Recovery coefficients, background variability and contrast were obtained from acquisitions of an IEC NEMA torso-phantom with hot sphere inserts.99m Tc was used to prepare the radioactive solutions and different sphere-tobackground ratio (RSB).The phantom was acquired using the 99m Tc-MAA clinical protocol.Images were reconstructed with the proprietary OSEM 3D algorithm (FLASH 3D, Siemens Healthcare), scatter and attenuation correction.The phantom results were validated on 99m Tc-MAA in vivo patient acquisitions.Results: The calibration factor for 99m Tc was 464.8 cps/MBq.Recovery coefficients vary with sphere volumes from 90% to 20%.Hot sphere contrast and activity quantification improve with higher iterations and subsets while the sphere to background ratio and the background variability increase.A balance between a satisfactory activity recovery and a low background variability (<12%) was obtained with 8 iterations, 8 subsets and no filtering.Hot spheres activity was determined with an accuracy ≤7%.Activity in liver from 99m Tc-MAA patient acquisitions was 8% (mean value) which was less than the administrated activity to the patients.This underestimation was attributed to some extrahepatic shunt.Conclusions: Activity recovery using the tested scanner can be achieved within an accuracy of 7%.With a simple scanner calibration procedure, the parameters of the clinical 99m Tc protocols can be optimized improving image quality and activity recovery according to the clinical requirements.
To evaluate the use of serial 18 F-choline (FCH) PET/CT scans in order to monitor the response to chemotherapy in patients (pts) with metastatic castrate-resistant prostate cancer (mCRPCa).Materials and methods.We collected FCH-PET/CT data from a consecutive series of 21 mCRPCa pre-treated pts (median age:73years) who met the inclusion criteria: such as visceral and non-visceral metastasis with clear uptake on a baseline FCH-PET/CT scan and no fewer than two scans separated by at least one month and by no more than 12 months whilst receiving chemotherapy.Eighteen pts were treated by taxanes and 3 with abiraterone.Change in FCH uptake (SUVmax of the index lesion; ΔSUVmax) during the course of treatment was compared with the clinical assessment response and PSA change (ΔPSA).The correlations were evaluated by using non-parametric tests, as appropriate.Results.The median interval time between PET/CT scans was 5 months (interquartile range-IQR: 3-7).Median (IQR) PSA value and SUVmax were 25(7.22-141)ng/mL, 15.7(11.3-17.83),22.9(7.7-92.5)ng/mL and 5.5(7.21-19.1)ng/mL respectively at the time of baseline and 2 nd PET/CT.The median ΔPSA and ΔSUVmax were -49.9% and 8.3%, respectively.No correlation between ΔPSA and ΔSUVmax was found (r=0.046;p=0.843).In accordance with the clinical assessment, 8 pts were responders, 4 had a stable and 9 a progressive disease.A significant overlap was reported for ΔPSA and clinical categories of response (p=0.685).Conversely, ΔSUVmax was significantly different in pts with a response to chemotherapy as compared to those with stable and progressive disease (p=0.005).Conclusions.ΔSUVmax, rather than ΔPSA, represents an important measure of response to chemotherapy and should be useful to stratify the prognosis of mCRPCa pts.A large multicenter prospective study is necessary to confirm these findings.
Karandeep Virdi is a content writer at Progressive Markets who harbors an active interest in medical devices, advancements in the medical field and the upcoming trends in the industry. He actively researches and writes articles about the evolution of the medical industry and technological advancements in the market. Karandeep has written extensively on topics covering medical devices, software technology used in the medical industry.
This review concerns methods of synthesis, NMR analysis and applications of isotope-labelled hydantoins.The hydantoin moiety is present in natural products and in extraterrestrial ice, indicating this to be an important compound in prebiotic chemistry.Bacterial transport proteins that scavenge hydantoins have been identified, isolated and characterised with isotope-labelling of hydantoins as an essential requirement to achieve this.These are Mhp1 from Microbacterium liquefaciens and PucI from Bacillus subtilis, transporting 5-arylsubstituted hydantoins and allantoin, respectively.The hydantoin ring is a useful centre in synthetic chemistry, especially for combinatorial chemistry, multicomponent reactions and in diversity-oriented synthesis.It is also found in pharmacologically active molecules, such as the anticonvulsant phenytoin.Hydantoins synthesised with isotope labels include hydantoin itself, allantoin, other 5-monosubstituted derivatives, phenytoin, other 5,5-disubstituted derivatives, N-substituted derivatives and other more complex molecules with multiple substituents.Analysis of isotope-containing hydantoins by NMR spectroscopy has been important for confirming purity, labelling integrity, specific activity and molecule conformation.Isotope-labelled hydantoins have been used in a range of biological, biomedical, food and environmental applications including metabolic and in vivo tissue distribution studies, biochemical analysis of transport proteins, identification and tissue distribution of drug binding sites, drug metabolism and pharmacokinetic studies and as an imaging agent.
In the previous few years we have witnessed to an increased diffusion of positron emission tomography/magnetic resonance (PET/MR) tomographs and equally an increasing number of clinical studies with these hybrid devices in both the neurological and psychiatric fields.Although PET/MR contains many features that facilitate its application in brain imaging, accurate quantification is still hindered by difficulties in developing MR-based attenuation correction methods.In this paper, we have reviewed the three main methods currently used for attenuation correction in PET/MR: namely segmentation-based methods including, atlas and template.In addition to procedures based on the combination of PET emission data and MR anatomical information (or reconstruction-based methods).Many research centers are actively working to refine available methods and substantial improvements are expected in future years.Clinical studies using PET/MR focused mainly on neurooncological and neurodegenerative disorders.Simultaneous PET/MR was shown to provide very promising scientific results and to be logistically more convenient for patients.More studies are expected in the near future, as the availability of PET/MR and the clinical use of new tracers for neurodegenerative disorders will further increase.
Molecular Metaphors is the application of squaryl building blocks towards creative functional group chemistry to produce lead compounds and imaging agents. This strategy is applied to rational drug design and to various imaging agents that would normally contain conventional functional group chemistry. These, include carboxylic acids, α -amino acids, peptide bonds and phosphonates. Moreover, the squaryl metaphor is a precursor to complex organic molecules involving functional group interchange (FGI) and rearrangements. This article discusses the application of these metaphors in the area of neurochemistry, especially NMDA receptors. An important area of drug design is the inhibition of angiotensin II enzyme by the use of losartan. This commercial drug contains a tetrazole moiety that can be modified using the squaryl group to give a semisquarate derivative. These concepts can extend to the semisquarate of ibuprofen. Moreover, a discussion on peptidomimetics regarding the substitution of the peptide bond for squaramide allows for a change in the biological properties due to modification at the peptide bond. Furthermore, the topic on how squaryl metaphors can be exploited primarily by the central 1,3-hydroxyamide sequence to the generation of a novel class of HIV protease inhibitors. Also, squaryl metaphors can be used to develop potential inhibitors of glutathione and novel anti-migraine drugs. The discussion continues on the design of anticancer drugs: in particular, a novel class of metalloproteases, including phosphonates for semisquaramides, leading to squaryl nucleosides. This review concludes with the application of squaryl metaphors in the design of positron emission tomography (PET) and magnetic resonance imaging (MRI) agents towards theranostics.
he Journal of Diagnostic Imaging in Therapy (JDIT) is published online by Open Medscience, based in Northern Ireland, UK.The aim of this journal is to address the requirements of researchers -specialising in nuclear medicine, diagnostic imaging and therapy by providing open access to peer-reviewed articles.These high quality published articles are available in both HTML and PDF formats.All published articles are assigned a unique CrossRef DOI number and the HTML version is given a CrossMark accreditation.The published articles highlight the application of diagnostic imaging with radionuclides, X-rays, magnetic resonance (MR), ultrasound (US) etc.The scope of these imaging modalities includes positron emission tomography (PET), single photon emission computed tomography (SPECT), hybrid imaging systems, radioguided surgery (RGS) and positron emission mammography (PEM).In addition included are the application of short and long-lived radioisotopes in research alongside the development of imaging agents and related targeted therapies.Furthermore,
We report the case of a 72-yr-old prostate cancer patient with biochemical failure (PSA = 2.8 ng/mL) after radical prostatectomy in whom both bone scintigraphy and 11 C-choline PET/CT detected an isolated focal pathological activity in the proximal diaphysis of the left tibia.Surgery was performed and histological analysis revealed enchondroma.The finding is discussed on the basis of the specificity of radiolabeled choline for prostate cancer vs. other tumors or inflammation processes.Particularly, proliferation or concomitant inflammatory processes associated with bone remodeling in enchondroma are discussed and related to 11 C-choline uptake.
Nuclear magnetic resonance (NMR) spectroscopy is a principal well-established technique for analysis of chemical, biological, food and environmental samples.This article provides an overview of the properties and applications of NMR-active nuclei (39 nuclei of 33 different elements) used in NMR measurements (solution-and solid-state NMR, magnetic resonance spectroscopy, magnetic resonance imaging) with biological and biomedical systems and samples.The samples include biofluids, cells, tissues, organs or whole body from different organisms (humans, animals, bacteria, fungi, plants) for detecting and quantifying metabolites or environmental samples (water, soils, sediments).Isolated biomolecules (peptides, proteins, nucleic acids) can be analysed for elucidation of atomic-resolution structure, conformation and dynamics and for characterisation of ligand and drug binding, and of protein-ligand, protein-protein and protein-nucleic acid interactions.NMR can be used for drug screening and pharmacokinetics and to provide information in the design and discovery of new drugs.NMR can also measure translocation of ions and small molecules across lipid bilayers and membranes, characterise structure, phase behaviour and dynamics of membranes and elucidate atomic-resolution structure, orientation and dynamics of membrane-embedded peptides and proteins.
Differentiated thyroid cancer (DTC) is a common endocrine tumor with increasing incidence and excellent prognosis. The therapy of thyroid cancer consists of thyroidectomy, thyroid hormone treatment and, depending on pathological stage, adjuvant radioactive iodine ablation (RIA). Because of the excellent outcome of DTC and the potential cancerous effect of iodine-131, in the last years there has been a huge number of articles addressing the issue of the incidence of second tumors in DTC patients. We will make a short critical review of some of these articles focusing on results reporting and interpretation. Methodological factors that may affect the obtained results will be highlighted for the benefit of the reader so that the risk associated to iodine-131 exposure will be balanced to the risk associated to other risk factors, including enhanced medical surveillance, shared genetic variability and environment factors and proper methodological study design. The review is finally a call to physicians involved in the therapy of these patients, primarily nuclear medicine physicians, endocrinologists and surgeons, to join their complimentary skill for the therapy of these patients.
The examination with lacrimal scintigraphy showed that the supine side-down eye position of the test subject inhibited the transfer of the tracer into the lacrimal sac. The result means that utilizing gravitation offers the patient a convenient alternative to prolong the ocular contact time of each eye drop.
Background: In our Institute PET/CT images are used for detecting, staging and monitoring various malignant tumours.Standard Uptake Value (SUV) is now common place in our clinical PET/CT oncology.Moreover, PET images are used for target volume definition in radiotherapy applications.Even if PET represents a powerful diagnostics tool, the quantitative data extracted from PET are affected by the limited resolution of the system.The aims of this work is to analysed by a phantom study the accuracy of the data quantified by our tomograph and the validation of the segmentation method used for radiotherapy applications.
Reirradiation of spinal metastases requires full consideration of previously delivered dose to the spinal cord thereby significantly constraining further dose delivery.The reirradiation of spinal metastases was frequently performed by Cyberknife or Tomotherapy [1,2].However, Cyberknife needs longer treatment time, possibly leading to a higher mental or physical burden to the patients with firm immobilization on the treatment couch, whereas Tomotherapy delivers rotational beams from all angles that may increase mean doses in organs at risk (OARs).Meanwhile, stereotactic body
The application of aptamers especially in the use of drug delivery systems (DDSs) has the potential to develop in vivo nanoparticles for theranosis (therapy+diagnosis).With the advent of medical imaging and radiotherapeutics, this area of research developing the next era of radiopharmaceuticals is both attractive and promising.Overall, nano-radiopharmaceuticals have the potential to solve several problems regarding the in vivo stability of aptamers.This paper discusses a study in the development and proof-of-concept of nano-aptamers and supporting its use as a nano-radiopharmaceutical for the treatment of breast cancer and other potentially related disease states.
Journal of Diagnostic Imaging in Therapy (JDIT) is published online by Open Medscience, based in Northern Ireland, UK.The aim of this new journal is to address the requirements of researchersspecialising in Nuclear and Medical Sciences -by providing open access to peer-reviewed articles.These high quality published articles on Nuclear and Medical sciences are available in both HTML and PDF formats.The published articles are to highlight the application of Diagnostic Imaging with radionuclides, X-rays, magnetic resonance (MR), ultrasound (US) etc.The scope of these imaging modalities include: positron emission tomography (PET), single photon emission computed tomography (SPECT), hybrid imaging systems, radioguided surgery (RGS) and positron emission mammography (PEM).Also included are the application of short and long-lived radioisotopes in research alongside the development of imaging agents and related targeted therapies.In addition,
Alzheimer's disease (AD) is a brain disorder with aggravating symptoms of memory loss and dementia mainly in the elderly population.Imaging tools of β-amyloid (Aβ) plaques are necessary for clinical and neuropsychological characteristics in AD.This is in order to gain global understanding of the disease by the design and selection of effective drugs.Positron emission tomography (PET) is a notable tool for drug advancement because of its high sensitivity and capacity to produce quantitative and kinetic data.PET amyloid imaging is an appropriate technique for studying the amyloid binding.Currently, Pittsburgh P ( 11 C-PIB), a benzothiazole compound, is an outstanding tracer used for attachment to the Aβ plaques.Other PET imaging probes already in use in clinical trials include thioflavin T, 11 C-SB-13, 18 F-GE-067, 18 F-AZD4694, 18 F-BAY94-9172 and 18 F-AV-45.PET imaging has received prominence
