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Nuclear Medicine Communications - Current Issue

Nuclear Medicine Communications - Current Issue
  1. Early monitoring of osteoporosis treatment response by technetium-99m-methylene diphosphonate bone scan
    imageObjective: The aim of this study was to investigate the effectiveness of a technetium-99m-methylene diphosphonate (99mTc-MDP) bone scan and the bone mineral density (BMD) test in monitoring the efficacy of osteoporosis (OP) treatment. Patients and methods: A total of 50 women with OP were prospectively enrolled in this study from January 2011 to October 2016 in our hospital. All the patients underwent a 99mTc-MDP whole-body bone scan and the BMD test before and after alendronate sodium treatment at 3, 6, 12 and 18 months, respectively. Bone metabolism rate on the 99mTc-MDP bone scan was analysed and expressed as the region-of-interest (ROI) ratio of target bones (L1–L4 vertebrae and femoral neck) to the control right tibia shaft, which was subsequently compared with the bone mass on BMD test at each time point of the treatment. Results: The mean ROI ratio of the L1 vertebra on the 99mTc-MDP bone scans decreased significantly starting at 3 months and continued to decrease at 6, 12 and 18 months, respectively (P<0.001). The mean ROI ratio decreased significantly starting at 6 months at the L2 (P<0.001) and L3 (P<0.001) and starting at 12 months at the L4 (P<0.001) and the right femoral head (P<0.001), respectively. In contrast, the BMD levels of the L1, L2, L3 and L4 vertebrae and the femoral neck increased significantly after 12, 12, 18, 18 and 18 months alendronate treatment respectively. Conclusion: 99mTc-MDP bone scan can detect the alendronate therapeutic efficacy for OP much earlier than the BMD test.



  2. Volumetric high-resolution computed tomography in evaluating pulmonary metastases from differentiated thyroid carcinoma: considerations for evolving the optimal diagnostic pathway
    No abstract available



  3. Normal bone and soft tissue distribution of fluorine-18-sodium fluoride and artifacts on 18F-NaF PET/CT bone scan: a pictorial review
    imageFluorine-18-sodium fluoride (18F-NaF) PET/CT is a relatively new and high-resolution bone imaging modality. Since the use of 18F-NaF PET/CT has been increasing, it is important to accurately assess the images and be aware of normal distribution and major artifacts. In this pictorial review article, we will describe the normal uptake patterns of 18F-NaF in the bone tissues, particularly in complex structures, as well as its physiologic soft tissue distribution and certain artifacts seen on 18F-NaF PET/CT images.



  4. Dual-phase 99mTc-MIBI imaging and the expressions of P-gp, GST-π, and MRP1 in hyperparathyroidism
    imageObjective: The aim of this study was to further elucidate the mechanisms of dual-phase technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) parathyroid imaging by exploring the association between early uptake results (EUR), delayed uptake results (DUR), and the retention index (RI) in dual-phase 99mTc-MIBI parathyroid imaging and P glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), and glutathione S-transferase-π (GST-π) expression in hyperparathyroidism (HPT). Patients and methods: Preoperative dual-phase (early and delayed) 99mTc-MIBI imaging was performed on 74 patients undergoing parathyroidectomy for HPT. EUR, DUR, and RI were calculated. P-gp, MRP1, and GST-π expressions were assessed using immunohistochemistry in resected tissue from HPT and control patients. The association between P-gp, MRP1, and GST-π expressions and EUR, DUR, and RI in HPT was evaluated. Results: The positive rate of dual-phase 99mT c-MIBI imaging was 91.89% (68/74) and the false-negative rate was 8.11% (6/74). P-gp and GST-π expressions were higher in tissues resected from control compared with HPT patients (47.37 and 81.5%, P<0.05); there was no difference in MRP1. EUR were associated with P-gp and GST-π expressions, and DUR were associated with MRP1 expression. There was a significant difference in MRP1 expression between RI greater than or equal to 0 and RI less than 0. There was no relationship between the sensitivity of dual-phase 99mTc-MIBI imaging and P-gp, MRP1, and GST-π expressions in resected parathyroid tissue. The six false-negative HPT cases consisted of three P-gp (−)/MRP1 (−) tissues, three P-gp (−)/GST-π (−) tissues, and four MRP1 (−)/GST-π (−) tissues. Conclusion: As P-gp and GST-π expressions were higher in tissues resected from control compared with HPT patients, 99mTc-MIBI may wash out faster from normal parathyroid tissue surrounding the lesion compared with the lesion itself, facilitating detection.



  5. The clinical significance of technetium-99m methylene diphosphonate bone scintigraphy findings in patients with rhabdomyolysis
    imageObjective: This study evaluated the relationship between bone scintigraphy finding and clinical factors and assessed the prognostic value of bone scintigraphy finding in patients with rhabdomyolysis. Patients and methods: We retrospectively enrolled 143 patients with rhabdomyolysis who had undergone bone scintigraphy. Bone scintigraphy was classified into three groups: no or equivocal soft tissue uptake, a localized uptake, and a diffuse uptake. The relationship of bone scintigraphy findings with clinical factors was evaluated. Multiple logistic regression analysis was performed to identify the risk factors for acute renal failure (ARF) and renal replacement therapy (RRT). Results: Of 143 patients, 52 (36.4%) experienced ARF and 12 (8.4%) required RRT. Among cases caused by exercise, 83.7% showed localized soft tissue uptake. Diffuse soft tissue uptake was only shown among the patients with rhabdomyolysis caused by drug and toxin. Patients with localized or diffuse soft tissue uptake had higher levels of serum creatine kinase, myoglobin, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase compared with patients with no or equivocal uptake (P<0.05). Multiple logistic regression analysis showed that age, female sex, and serum phosphate level were associated with a risk for ARF and only serum creatinine level was associated with a risk for RRT (P<0.05). Bone scintigraphy findings failed to show significance for predicting ARF and RRT (P>0.05). Conclusion: Soft tissue uptake on bone scintigraphy in patients with rhabdomyolysis was related to etiologies and showed limited value for predicting ARF and RRT.


  6. Patient release criteria following radioactive iodine-131 treatment in the light of international practice: where does South Africa fit in?
    imageThe release from hospital of patients treated with radioactive iodine-131 (131I) remains a controversial issue as a result of the range of guidelines implemented by national regulatory bodies responsible for radiation protection in various countries worldwide. The aim of this study was to review and analyse the literature on patient release criteria (PRC) applied internationally in an attempt to achieve a justifiable approach to setting equivalent criteria in South Africa. In 2016, the South African Department of Health, Directorate: Radiation Control added conditions (numbers 50 and 90), to licences to use radioactive nuclides. These conditions state that patients must be hospitalized when the dose rate at 1 m is above 25 μSv/h, or more than 555 MBq of iodine-131 was administered to the patient. However, these criteria do not consider patients’ socioeconomic conditions. A literature survey was carried out of articles detailing PRC from high-income countries as well as those in the middle-income and lower-income groups. Socioeconomic conditions within countries were determined using the International Monetary Fund lists of gross domestic product. The results from the literature have shown that in setting PRC, several countries have considered the socioeconomic conditions prevailing in their countries to achieve harmony between public protection and cost associated with hospitalization. The South African authority conditions must be seen in the context of the approach followed by other countries. Considering the international context, a justifiable, and potentially implementable, guideline or policy for improving individualized and more caring patient management is advocated.



  7. Refining the management of patients with hepatocellular carcinoma integrating 11C-choline PET/CT scan into the multidisciplinary team discussion
    imageObjective: The aim of this study was to report the impact of 11C-choline PET/CT on the management of patients with hepatocellular carcinoma (HCC) and incorporate into a refined algorithm combining diagnostic imaging and multidisciplinary team (MDT) discussion. Patients and methods: From February 2010 to February 2016, the charts of all patients discussed in the liver MDT were revised. Suspected or confirmed HCC lesions or Barcelona Clinic Liver Cancer stages A, B or C with a 11C-choline PET/CT performed in our hospital were included in the analyses. Overall, 73 patients (male : female=59 : 14; median age: 75 years) were enrolled. Forty-two (57%) patients were newly diagnosed, whereas 31 (43%) came to our attention at disease recurrence. Seven (10%) patients were Barcelona Clinic Liver Cancer stage 0, 31 (42%) patients were stage A, 15 (20%) patients were stage B, and 18 (25%) patients were stage C. The reference standards for ultimate imaging validation were either histology or MDT consensus. A minimum follow-up of 6 months was established. Results: Overall eight (10%) patients were initially referred for chemotherapy (sorafenib), 43 (59%) for surgery, two (3%) for surgery or transarterial embolization, five (7%) for follow-up only, one (1%) for extrahepatic radiotherapy, seven (10%) for stereotactic body radiation therapy of the liver, six (8%) for transarterial embolization, and one (1%) for liver transplant. After 11C-choline PET/CT and MDT discussion, in seven patients the diagnosis changed, in six patients the treatment was changed, and in nine patients both the diagnosis and the treatment were changed. Overall, in 30% of our patients, the diagnosis or treatment was altered on the basis of our algorithm of management. Conclusion: The incorporation of 11C-choline PET/CT into the MDT discussion altered the diagnosis/treatment of one-third of HCC patients. We propose a novel diagnostic algorithm to be refined in referral centers for HCC management.



  8. Role of various semiquantitative parameters of 18F-FDG PET/CT studies for interim treatment response evaluation in non-small-cell lung cancer
    imagePurpose: The aim of this study was to prospectively evaluate the role of various semiquantitative parameters obtained from fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT in interim treatment response assessment in biopsy-proven non-small-cell lung cancer (NSCLC) and to find the best parameter, if any. Materials and methods: Totally, 32 patients (male/female: 25/7) with biopsy proven NSCLC and a mean age of 54.71±12.65 years were enrolled in the study. Each patient underwent whole-body 18F-FDG PET/CT scan after injecting 5.18–7.77 MBq/kg of 18F-FDG intravenously at baseline and after four cycles of chemotherapy. Five parameters – that is, target-to-background ratio (TBR), maximum standardized uptake value (SUVmax), average standardized uptake value (SUVavg), whole-body metabolic tumor volume (MTVwb), and whole-body total lesion glycolysis (TLGwb) – were evaluated for both scans along with their percentage changes ([INCREMENT]). Patients were divided into two response groups as per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria: responders and nonresponders. All parameters were compared among the two response groups using appropriate statistical methods; P value of less than 0.05 was considered significant. Results: All postchemotherapy parameters were found to have a significant role in the prediction of two response groups. Post-TBR had highest area under the receiver operating characteristic curve of 0.83 with a sensitivity and specificity of 75 and 82%, respectively, at a cutoff value of 4. The [INCREMENT]s, [INCREMENT]MTVwb, [INCREMENT]TLGwb, and [INCREMENT]SUVmax were significant with cutoffs of −56, −75, and −32%, respectively. [INCREMENT]MTVwb had the highest area under the receiver operating characteristic curve of 0.83 with sensitivity and specificity of 81.25%. In multivariate analysis, post-TBR and [INCREMENT]MTVwb were found to be the independent variables for prediction of interim treatment response. Conclusion: Our study proves that a multitude of semiquantitative parameters as documented above differ significantly between two response groups in patients with advanced stage NSCLC receiving chemotherapy. Moreover, parameters in combination (ΔMTV and post-TBR) with appropriate cutoffs can predict response groups with acceptable reliability.



  9. Characterization of resolution, sensitivity, and shielding of a gamma-probe for sentinel lymph node localization: an experimental study
    imageObjective: The aim of this study was to evaluate angular, spatial, and energy resolution, sensitivity, and shielding of a gamma-probe. Materials and methods: The EUROPROBE II gamma-probe (EuroRad) with sources of technetium-99m was assessed according to NEMA NU-3-2004. Resolution tests were evaluated considering the full width at half maximum (FWHM). The following parameters were evaluated: angular resolution in air, spatial resolution with a scattering medium and in air, energy resolution, and sensitivity and shielding. The collimator was used to evaluate angular and spatial resolution, sensitivity, and shielding. Background radiation was considered and did not affect the counts. Results: FWHM of angular resolution (at 3/30 cm) was 39.17°/33.13° with the collimator and 74.08°/71.51° without the collimator; FWHM of spatial resolution in air at 10 mm was 13.32 mm with the collimator and 21.23 mm without the collimator. Energy resolution (%FWHM) was 20.51%. Sensitivity at 10 mm was 4.642±5 cps/MBq without the collimator and 1.063±2 cps/MBq with the collimator; shielding effectiveness of the probe tip was 99.52%. Background was not relevant to the counts. Conclusion: We showed that the collimator improved angular and spatial resolution to the detriment of sensitivity. Feasible results of energy resolution, sensitivity, and shielding were achieved.



  10. Finding the sweet spot for metformin in 18F-FDG-PET
    imagePurpose: The effect of oral hypoglycemic agents on fluorine-18-flurodeoxyglucose (18F-FDG) uptake is less understood than the effect of exogenous insulin. In this study, the effect of withholding metformin on 18F-FDG distribution in subsequent PET imaging was evaluated. Patients and methods: A retrospective observational study was carried out. A total of 15 patients taking metformin were grouped according to the time interval from the last dose of metformin to 18F-FDG-PET. Those who received PET after stopping metformin for less than 24 h were compared with those stopping metformin 24–48 h before PET. The 18F-FDG uptake and PET image fidelity for these groups were compared qualitatively and the associated blood glucose was recorded. The average standardized uptake value of the liver, tongue, and subcutaneous tissues among the groups were also compared. Results: The 18F-FDG-PET distribution and image quality were found to be the best at time points greater than 24 h following metformin dose. There was significantly increased 18F-FDG uptake in the liver and tongue and tongue-to-liver ratio in patients who had metformin within 24 h of 18F-FDG-PET compared with those who last had metformin greater than 24 h before 18F-FDG-PET; however, the 18F-FDG uptake in the subcutaneous tissues was unchanged. Conclusion: Less than 24 h between metformin dose and 18F-FDG-PET resulted in increased muscle and fat uptake in addition to increased bowel uptake. Abnormal 18F-FDG uptake can limit the diagnostic quality of an exam and affect 18F-FDG uptake in cancer. The emerging role of biguanides in the treatment of cancer calls for more personalized standardization for 18F-FDG-PET in the presence of oral hypoglycemic agents.


  11. Evaluation of tomographic image quality of extended and conventional parallel hole collimators using maximum likelihood expectation maximization algorithm by Monte Carlo simulations
    imageObjective: One of the major problems associated with parallel hole collimators (PCs) is the trade-off between their resolution and sensitivity. To solve this problem, a novel PC – namely, extended parallel hole collimator (EPC) – was proposed, in which particular trapezoidal denticles were increased upon septa on the side of the detector. Materials and methods: In this study, an EPC was designed and its performance was compared with that of two PCs, PC35 and PC41, with a hole size of 1.5 mm and hole lengths of 35 and 41 mm, respectively. The Monte Carlo method was used to calculate the important parameters such as resolution, sensitivity, scattering, and penetration ratio. A Jaszczak phantom was also simulated to evaluate the resolution and contrast of tomographic images, which were produced by the EPC6, PC35, and PC41 using the Monte Carlo N-particle version 5 code, and tomographic images were reconstructed by using maximum likelihood expectation maximization algorithm. Results: Sensitivity of the EPC6 was increased by 20.3% in comparison with that of the PC41 at the identical spatial resolution and full-width at tenth of maximum here. Moreover, the penetration and scattering ratio of the EPC6 was 1.2% less than that of the PC41. The simulated phantom images show that the EPC6 increases contrast-resolution and contrast-to-noise ratio compared with those of PC41 and PC35. Conclusion: When compared with PC41 and PC35, EPC6 improved trade-off between resolution and sensitivity, reduced penetrating and scattering ratios, and produced images with higher quality. EPC6 can be used to increase detectability of more details in nuclear medicine images.



  12. Brown adipose tissue detected by PET/CT imaging is associated with less central obesity: Erratum
    No abstract available



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