31 research outputs found
PET/CT and PET/MRI in head and neck malignancy
No full textCombined 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT) has an established role in the staging of difficult cases of head and neck (HN) squamous cell carcinoma (SCC), looking for an unknown primary, assessing response post-chemotherapy at 3–6 months, and differentiating relapse from treatment effects in patients suspected to have tumour recurrence. The PET NECK trial, comparing PET/CT surveillance versus neck dissection in advanced head and neck cancer showed survival was similar among patients who underwent PET/CT-guided surveillance and those who underwent planned neck dissection, but surveillance was more cost-effective. There is growing interest in the use of hypoxia PET tracers, especially in targeting radiotherapy, where the radiotherapy dose can be boosted in regions of hypoxia; the use of 68Ga peptide tracers in neuroendocrine malignancy and also in the growing field of combined PET/magnetic resonance imaging (MRI). PET/MRI has the advantage of increased anatomical detail and radiation dose reduction combined with the molecular and metabolic data from PET, although PET/CT has the advantage in better sensitivity for imaging lung metastases. Thus far, there is good agreement between PET/CT and PET/MRI with high correlation between semi-quantitative measurements in primary, nodal, osseous, and soft-tissue lesions imaging. PET/MRI may indeed provide greater accuracy than the currently available imaging procedures in the staging and later treatment response evaluation in HNSCC
Review article: PET and PET/CT imaging of skeletal metastases
No full textBone scintigraphy augmented with radiographs or cross-sectional imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI), has remained the commonest method to diagnose and follow up skeletal metastases. However, bone scintigraphy is associated with relatively poor spatial resolution, limited diagnostic specificity and reduced sensitivity for bone marrow disease. It also shows limited diagnostic accuracy in assessing response to therapy in a clinically useful time period. With the advent of hybrid positron emission tomography (PET)/CT scanners there has been an increasing interest in using various PET tracers to evaluate skeletal disease including [(18)F] fluoride (NaF) as a bone-specific tracer and [(18)F] fluorodeoxyglucose and [(18)F] choline as tumour-specific tracers. There is also early work exploring the receptor status of skeletal metastases with somatostatin receptor analogues. This review describes the potential utility of these tracers in the assessment of skeletal metastases
G.J.R. Cook, M.N. Maisey, K.E. Britton and V. Chengazi, (eds.): Clinical nuclear medicine, 4th edition.
No full textValidation of new image-derived arterial input functions at the aorta using 18F-fluoride positron emission tomography
No full textObjectives (i) To validate two new image-based methods for finding the plasma arterial input function (AIF) and evaluate the performance of these and two similar techniques against arterial sampling. (ii) To evaluate the performance of all four image-derived AIF (IDAIF) methods against arterial sampling for measuring the 18F plasma clearance (Ki) to the lumbar spine.Methods Eight healthy postmenopausal women had a 18F-fluoride positron emission tomography scan of the lumbar spine. Venous blood samples were used to estimate the IDAIFs from: (i) a fixed population-based partial volume correction (PVC) factor method, (ii) a variable PVC factor method, (iii) the Chen method, and (iv) the Cook–Lodge method. Continuous arterial sampling and the respective Ki values were used as the gold standard against which the performance of the IDAIF methods was compared.Results The IDAIFs were compared with direct arterial sampling in terms of the area under the curve values. The percentage root mean square error in area under the curves compared with arterial sampling were: (i) fixed PVC: 12.7%, (ii) variable PVC: 12.0%, (iii) Chen: 39.0%, and (iv) Cook–Lodge: 17.3%. There were small but significant differences in the Ki values found by all four methods compared with arterial sampling. Bland–Altman plots of Ki values showed the best agreement for the variable and fixed PVC methods with a standard deviation of 0.0026 and 0.0030 ml/min/ml, respectively.Conclusion The differences in the Ki values obtained at the lumbar spine using direct arterial sampling and any of the IDAIF methods at the aorta were clinically nonsignificant. The variable PVC and fixed PVC methods performed better than the Cook–Lodge and Chen methods
Validation of image-derived arterial input functions at the femoral artery using 18F-fluoride positron emission tomography
No full textIntroduction The use of image-derived arterial input functions (IDAIF) for the dynamic quantification of bone metabolism using 18F-fluoride positron emission tomography 18F-PET is an attractive alternative to direct arterial blood sampling.Purposes (a) To validate a method for obtaining the IDAIF by imaging the femoral artery against a method for deriving the IDAIF at the aorta that was previously validated against direct arterial sampling. (b) To compare the accuracy of bone plasma clearance measurements (Ki) at the total hip site obtained using the femoral artery IDAIF against Ki values at the same site obtained using the aorta IDAIF.Methods Twelve healthy postmenopausal women with a mean age of 62.6 years (range, 52.3–70.6 years) had 60-min dynamic 18F-PET scans of the lumbar spine and proximal femur 2 weeks apart. The femoral artery IDAIF was obtained from the proximal femur scan using four different algorithms: (a) fixed partial volume correction (PVC) method; (b) variable PVC method; (c) Chen method; and (d) Cook–Lodge method. The aorta IDAIF was obtained from the lumbar spine scan using a previously validated method and the respective Ki values in the hip were used to assess the performance of each of the femoral artery algorithms.Results When the femoral artery IDAIF methods were compared with the aorta IDAIF in terms of the area under the curve AUC values calculated in 4-min time intervals over 0–60 min, the absolute root mean square errors were: (a) fixed PVC, 0.52; (b) variable PVC, 0.54; (c) Chen, 0.72; and (d) Cook–Lodge, 0.49 in MBq s/ml. There were small, but statistically significant differences, in the Ki values found by all four femoral artery IDAIF methods when compared with the figures obtained using the aorta IDAIF. Bland–Altman plots of Ki values showed the best agreement for the fixed PVC method with a standard deviation of 0.0020 ml/min/ml, followed by variable PVC, Cook–Lodge and Chen method with standard deviations of 0.0022, 0.0024 and 0.0042 ml/min/ml, respectively.Conclusion We have demonstrated that it is possible to measure regional bone turnover at the hip without the need to perform direct arterial sampling to acquire the arterial input function (AIF). The differences in the Ki values obtained at the hip by using aorta IDAIF and any of the four image-based AIF methods at the femoral artery were small and clinically insignificant. The performance of fixed PVC, variable PVC and Cook–Lodge method was similar although the latter was less robust than the other two methods
Preclinical development and characterisation of 99mTc-NM-01 for SPECT/CT imaging of human PD-L1
No full textThe level of expression of programmed cell death-1 (PD-1)/programmed death ligand-1 (PD-L1) is a predictive biomarker for cancer immunotherapy, however, its detection remains challenging due to tumour heterogeneity and the influence from the binding of therapeutic agents. We recently developed [99mTc]-NM-01 as a companion diagnostic imaging agent for non-invasive molecular imaging of PD-L1 by single-photon emission computed tomography (SPECT). The aim of the study was to evaluate the [99mTc] radiolabelling of GMP graded NM-01 and its pharmacology, pharmacokinetics and toxicology. NM-01 bound specifically to human PD-L1 (Kd=0.8 nM) and did not interfere with the binding of the anti-PD-L1 antibody atezolizumab. NM-01 can bind various PD-L1-positive cancer cell lines and only interact with PD-L1 expressed on the cell surface. In SPECT/CT imaging, high [99mTc]-NM-01 accumulation was observed in the HCC827 mouse xenografted tumour model (30-min: 1.50 ± 0.27 %ID/g; 90-min: 1.23 ± 0.18 %ID/g), demonstrated a predominantly renal elimination (high uptake in bladder and kidney), while activity in the blood pool and other major organs remained low. The tumour-to-muscle and tumour-to-blood ratios were comparable with/without atezolizumab (P<0.04) but were significantly lowered when co-injected with excess NM-01 (P=0.04 and P=0.01, respectively.) The blood clearance of [99mTc]-NM-01 is bi-phasic; consisting of an initial fast washout phase with half-life of 2.1 min and a slower clearance phase with half-life of 25.4 min. In an intravenous extended single-dose toxicity study, no treatment-related changes were observed and the maximum tolerated dose of [99mTc]-NM-01 was 2.58 mg/kg. [99mTc]-NM-01 has suitable properties as a potential candidate for SPECT/CT imaging of PD-L1 assessment in cancer patients.</p
Biomass Burning in the Global Environment: First Results from the IGAC/BIBEX Field Campaign STARE/TRACE-A/SAFARI-92
No full textSince the STAREITRACE-NSAFARI-92 Science Team is too numerous to be included in the author list, only those who have contributed text to this paper are listed on the title page. The others are: A-L. Ajavon, C. Anderson, T.W. Andreae, H.J. Annegarn, C.B. Archer, P. Artaxo, E. Atlas, R.E. Babbitt, J. Barsby, J. Beer, R.J. Bendura, D. Bergmann, D.R. Blake, G.E. Bodeker, T. Boyle, J.D. Bradshaw, J.K. Broadbent, E.V. Browell, E.G. Brunke, R.A Burke, H. Cachier, J. Cafmeyer, D.J. Cahoon, R Chadyendiya, M. Chaitwa, T.-Y. Chen, G.J.R Coetzee, W.R Cofer III, J.E. Collins, B. Cros, P. Cunningham, G. de Beer, A de Kock, R. Delmas, RD. Diab, P. Dowty, B.L. Duigan, F. Echalar, M. Edwards, W. Elbert, T. Fickinger, A. Gaudichet, S.J. Godefroy, G.L. Gregory, M. Guest, G.W. Harris, G. Helas, G. Held, J.L. Hery, J.M. Hoell, R Hudson, C. Jambert, A Joubert, M.R. Jury, P. Kiillberg, RP. Karimanzira, J.B. Kauffman, J. Kendall, J. Kim, V.W.J.H. Kirchhoff, M.A Kneen, R. Koppmann, T.N. Krishnamurti, F. Kruger, T. Kuhlbusch, C. Labuschagne, J.P. Lacaux, C. Liousse, E. Lynch, S.A. Macko, W. Maenhaut, C. Manickum, B. Martincigh, P. Masclet, J.A Mason, G.K. Mather, M.A Mazurek, D.P. McNamara, D.J. McRae, F. Meixner, W.L. Miller, E. Mpunduma, E. Mravlag, W. Munyanyiwa, A. Mwale, S. O'Beirne, U. Parchatka, D. Parsons, K. Pickering, J.J. Pienaar, S. Piketh, J.P. Pinto, W. Pollock, A Potgieter, RA. Preston-Whyte, M.W. Raynor, R Rorich, J. Rudolph, G.W. Sachse, I. Salma, S.T. Sandholm, W. Schneider, M.C. Scholes, M. Schormann, G.C. Schulze, M. Scourfield, D.I. Sebacher, M.K. Seely, R. Shea, H.B. Singh, N. Snow, F. Sokolic, B. Stefanski, R. Swap, R.W. Talbot, I. Taviv, A Tegen, M. Thompson, G.R. Tosen, L. Trollope, W.S.W. Trollope, M.M. Truter, S. Tsure, C. Turner, P. Tyson, J. van Heerden, D. Walmsley, D.E. Ward, M.G. Weber, F. Weirich, M. Welling, F.G. Wienhold, E.L. Winstead, T. Zenker, RG. Zepp, and M. Zunckel.Biomass burning is now recognized as a major source of important trace gases, including CO₂, NO₂, CO and CH₄, and of aerosol particles. It takes on many forms: burning of forested areas for land clearing, extensive burning of grasslands and savannas to sustain grazing lands, burning of harvest debris, and use of biomass fuel for heating.https://link.springer.com/chapter/10.1007/978-1-4615-2524-0_
