Papers by Geoffrey Schembri
The Journal of Nuclear Medicine, May 1, 2009
The Journal of Nuclear Medicine, Aug 1, 2013
Learning Objectives: On successful completion of this activity, participants should be able to de... more Learning Objectives: On successful completion of this activity, participants should be able to describe (1) advantages and shortcomings of planar versus SPECT V/Q scanning, (2) advantages and disadvantages of CT pulmonary angiography versus V/Q SPECT in the investigation of pulmonary embolism, and (3) an overview of image acquisition, processing, display, and reporting of V/Q SPECT studies. Financial Disclosure: The authors of this article have indicated no relevant relationships that could be perceived as a real or apparent conflict of interest. CME Credit: SNMMI is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to sponsor continuing education for physicians. SNMMI designates each JNM continuing education article for a maximum of 2.0 AMA PRA Category 1 Credits. Physicians should claim only credit commensurate with the extent of their participation in the activity. For CE credit, participants can access this activity through the SNMMI Web site (http:// www.snmmi.org/ce_online) through September 2016. Planar ventilation-perfusion (V/Q) scanning is often used to investigate pulmonary embolism; however, it has well-recognized limitations. SPECT overcomes many of these through its ability to generate 3-dimensional imaging data. V/Q SPECT has higher sensitivity, specificity, and accuracy than planar imaging and a lower indeterminate rate. SPECT allows for new ways to display and analyze data, such as parametric V/Q ratio images. Compared with CT pulmonary angiography, SPECT has higher sensitivity, a lower radiation dose, fewer technically suboptimal studies, and no contrast-related complications. Any nuclear medicine department equipped with a modern hybrid scanner can now perform combined V/Q SPECT with CT (using low-dose protocols) to further enhance diagnostic accuracy. V/Q SPECT (with or without CT) has application in other pulmonary conditions and in research.
Journal of Nuclear Medicine
Clinical Endocrinology
ObjectiveWe propose a new scoring system (I‐PET) combining whole body scan (WBS) and FDG findings... more ObjectiveWe propose a new scoring system (I‐PET) combining whole body scan (WBS) and FDG findings to identify patients who have or are likely to become refractory to radioactive iodine.DesignRetrospective analysis of 142 patients age >18 with differentiated thyroid cancer who had a F‐18 labelled fluoro‐2‐deoxyglucose (18F‐FDG) positron emission tomography (PET) and WBS within a 6‐month period between 2010 and 2020. Pairs of 18F‐FDG PET and WBS were reviewed by three independent nuclear medicine physicians and an I‐PET score was assigned: I‐PET [0]: Iodine −ve/FDG −ve, I‐PET [1]: Iodine +ve/FDG −ve, I‐PET [2]: Iodine +ve/FDG +ve and I‐PET [3]: Iodine −ve/FDG +ve. Patients with FDG +ve lesions (I‐PET [2] and I‐PET [3]) were further classified into groups A and B if SUVmax was ≤5 or >5, respectively. Follow‐up data were obtained by chart review. Progression was defined as structural progression as per RECIST 1.1 or further surgical intervention; or biochemical progression as unst...
The Journal of Nuclear Medicine, May 1, 2020
Asia Oceania Journal of Nuclear Medicine and Biology, 2015
Objective(s): Peptide Receptor Radionuclide Therapy (PRRT) with yttrium-90 (90Y) and lutetium-177... more Objective(s): Peptide Receptor Radionuclide Therapy (PRRT) with yttrium-90 (90Y) and lutetium-177 (177Lu)-labelled SST analogues are now therapy option for patients who have failed to respond to conventional medical therapy. In-house production with automated PRRT synthesis systems have clear advantages over manual methods resulting in increasing use in hospital-based radiopharmacies. We report on our one year experience with an automated radiopharmaceutical synthesis system. Methods: All syntheses were carried out using the Eckert & Ziegler Eurotope’s Modular-Lab Pharm Tracer® automated synthesis system. All materials and methods used were followed as instructed by the manufacturer of the system (Eckert & Ziegler Eurotope, Berlin, Germany). Sterile, GMP-certified, no-carrier added (NCA) 177Lu was used with GMP-certified peptide. An audit trail was also produced and saved by the system. The quality of the final product was assessed after each synthesis by ITLC-SG and HPLC methods. R...
The Journal of Nuclear Medicine, 2019
1. University of Texas MD Anderson Cancer Center, Houston, TX, United States Although much have b... more 1. University of Texas MD Anderson Cancer Center, Houston, TX, United States Although much have been learned about the biology and natural history of neuroendocrine neoplasms over the past two decades, our understanding of these topics is still evolving due to continuing improvements in molecular diagnostics and therapeutics. Our recent analyses using Surveillance, Epidemiology, and End Results (SEER) registry data showed the incidence and prevalence of neuroendocrine tumors are continuing to rise (Dasari et al, JAMA Oncology 2017). The ageadjusted incidence rate increased 6.4-fold from 1973 (1.09 per 100 000) to 2012 (6.98 per 100 000). The estimated 20-year limited-duration prevalence of NETs in the United States on January 1, 2014, was 171,321. The overall survival for all NETs improved from the 2000-2004 period to the 2009-2012 period (hazard ratio [HR], 0.79; 95%CI, 0.73-0.85). Even larger increases in OS between these periods were noted in distant-stage gastrointestinal NETs (...
European Thyroid Journal, 2021
Objective: Our study aimed to analyse temporal trends in radioactive iodine (RAI) treatment for t... more Objective: Our study aimed to analyse temporal trends in radioactive iodine (RAI) treatment for thyroid cancer over the past decade; to analyse key factors associated with clinical decisions in RAI dosing; and to confirm lower activities of RAI for low-risk patients were not associated with an increased risk of recurrence. Methods: Retrospective analysis of 1,323 patients who received RAI at a quaternary centre in Australia between 2008 and 2018 was performed. Prospectively collected data included age, gender, histology, and American Joint Committee on Cancer stage (7th ed). American Thyroid Association risk was calculated retrospectively. Results: The median activities of RAI administered to low-risk patients decreased from 3.85 GBq (104 mCi) in 2008–2016 to 2.0 GBq (54 mCi) in 2017–2018. The principal driver of this change was an increased use of 1 GBq (27 mCi) from 1.3% of prescriptions in 2008–2011 to 18.5% in 2017–2018. In patients assigned as low risk per ATA stratification, l...
Nuclear Medicine Communications, 2020
Background [67Ga]Ga-citrate scanning has been used to investigate patients with known or suspecte... more Background [67Ga]Ga-citrate scanning has been used to investigate patients with known or suspected infection for over 50 years, continuing to maintain a clinical niche in many centres. The introduction of single photon emission tomography/computed tomography (SPECT/CT) in addition to planar imaging has improved the specificity of diagnosis. Aim To examine the experience of modern [67Ga]Ga-citrate scanning in a single tertiary referral centre, considering the diagnostic yield of the study. Methods A retrospective audit was undertaken of 100 consecutive [67Ga]Ga-citrate scans at Royal North Shore Hospital, Sydney. Recorded information included patient demographics, clinical information/history, and primary and secondary diagnoses. Subgroup analyses included patients with a confirmed diagnosis of infection or a suspected diagnosis of infection. Results The median age of patients was 68.5 years. Totally, 39/100 patients undergoing [67Ga]Ga-citrate scanning presented with a confirmed sit...
Practical Radiation Oncology, 2018
We investigated the impact of 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) on... more We investigated the impact of 18F-fluoroethyltyrosine (FET) positron emission tomography (PET) on radiotherapy planning for patients diagnosed with glioblastoma (GBM) and a suspected non-enhancing tumor compared with standard magnetic resonance imaging (MRI). We performed volumetric analyses between clinical target volumes and respective biological target volumes using Wilcoxon signed-rank tests. In conclusion, FET-PET may help improve delineation of GBM in cases with a suspected non-enhancing component and reduce the risk of potential geographical miss.
Journal of Clinical Neuroscience, 2018
We aimed to determine the utility of FET PET in the management of indeterminate CNS lesions found... more We aimed to determine the utility of FET PET in the management of indeterminate CNS lesions found on MRI. We performed a retrospective analysis of patients with FET PET at a single tertiary institution from 2011 to 2015. FET PET images were processed using usual methods and measurements taken including SUVmax, TBRmax, and analysis of dynamic series where available (Kipeak, Vdpeak, as well as tumor: background ratio for these variables). Correlation studies were performed using ANOVA between cohorts of high-grade histology, low-grade histology, and benign histology/stable on observation. Thirty-five patients were included, of whom 34 were suitable for analysis with median follow-up of 5 months. The positive predictive value of FET PET in this cohort was 83.3%. FET SUVmax differentiated between patients with high-grade (mean SUV 3.38, 95% CI 2.21-4.55), low-grade (1.88, 95% CI 1.33-2.43) and benign/observation (1.42, 95% CI 1.13-1.71) cohorts (p = 0.0003). Similarly, tumour to brain ratio was significant (p < 0.0001). Kipeak distinguished between high grade and observation cohorts (p = 0.036), as did KiTBR (p = 0.025). Vd peak was not significantly different in these two cohorts (p = 0.057) but Vd TBR was (p = 0.041). In conclusion, FET PET demonstrated a high positive predictive value for glioma in patients with indeterminate brain lesions on MRI. The combination of negative FET and negative FDG PET scans may predict an indolent clinical course. Confirmatory trials are needed to establish the potential value of FET PET in guiding surgical management in this cohort.
Journal of clinical rheumatology : practical reports on rheumatic & musculoskeletal diseases, Jan 26, 2017
Theranostics, 2017
Background: PET scans using FDG and somatostatin receptor imaging agents have both been used to s... more Background: PET scans using FDG and somatostatin receptor imaging agents have both been used to study neuroendocrine tumours. Most reports have documented the sensitivity and specificity of each radiopharmaceutical independently, and even suggested the superiority of one over the other for different grades of disease. Aim: The aim of this work was to develop a grading scheme that describes the joint results of both the FDG and somatostatin receptor imaging PET scans in staging subjects with neuroendocrine tumours in a single combined parameter. The grading scheme that has been developed is referred to as the NETPET grade. Methods: This is a retrospective study which assessed subjects who had both FDG and somatostatin receptor PET imaging at our institution within 31 days of each other. The NETPET grade was assigned by experienced nuclear medicine physicians and compared with other clinical data such as WHO grade and overall survival. Results: In the period 2011-2015 we were able to ...
Clinical Nuclear Medicine, 2016
prostate-specific membrane antigen (PSMA) PET/CT is a relatively new and highly sensitive imaging... more prostate-specific membrane antigen (PSMA) PET/CT is a relatively new and highly sensitive imaging modality used in staging metastatic prostate cancer. We report a case of a 65-year-old man with newly diagnosed prostate carcinoma who had a PSMA PET/CT scan for staging of his disease. A PSMA-avid right pelvic mass was identified anterior to the sacrum. Surgical removal and histopathological examination of this lesion revealed the diagnosis of schwannoma. It is important to be aware that schwannoma may also show avid uptake on PSMA PET/CT scan and may potentially lead to an incorrect diagnosis of metastatic prostate carcinoma.
Seminars in nuclear medicine, 2016
Gallium-68 ((68)Ga) is a positron-emitting radionuclide suitable for positron emission tomography... more Gallium-68 ((68)Ga) is a positron-emitting radionuclide suitable for positron emission tomography (PET) imaging that has a number of convenient features-it has a physical half life of 68 minutes, it is generator produced at the PET facility and needs no local cyclotron, and being a radiometal is able to be chelated to a number of useful molecules for diagnostic imaging with PET. (68)Ga has recently been investigated as a radiotracer for ventilation and perfusion (V/Q) lung imaging. It is relatively easy to produce both V/Q radiopharmaceuticals labeled with (68)Ga for PET studies, it offers higher spatial resolution than equivalent SPECT studies, the short half life allows for multiple (repeated) scans on the same day, and low amounts of radiotracer can be used thus limiting the radiation dose to the subject. In the usual clinical setting requiring a V/Q scan, that of suspected pulmonary embolism, the role of (68)Ga V/Q PET may be limited from a logistical perspective, however, in no...
Society of Nuclear Medicine Annual Meeting Abstracts, May 1, 2012
Society of Nuclear Medicine Annual Meeting Abstracts, May 1, 2011
Society of Nuclear Medicine Annual Meeting Abstracts, May 1, 2009
Society of Nuclear Medicine Annual Meeting Abstracts, May 1, 2010
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Papers by Geoffrey Schembri