Six country vignettes: Strengthening radiotherapy and theranostics.

BACKGROUND: For cancer patient populations worldwide, the synchronous scale-up of diagnostics and treatments yields meaningful gains in survival and quality of life. Among advanced cancer therapies, radiotherapy (RT) and theranostics are key to achieving practical, high-quality, and personalized precision medicine - targeting disease manifestations of individual patients and broad populations, alike. Aiming to learn from one another across different world regions, the six country vignettes presented here depict both challenges and victories in de novo establishment or improvement of RT and theranostics infrastructure. METHODS: The International Atomic Energy Agency (IAEA) convened global RT and theranostics experts from diverse world regions and contexts to identify relevant challenges and report progress in their own six countries: Belgium, Brazil, Costa Rica, Jordan, Mongolia, and South Africa. These accounts are collated, compared, and contrasted herein. RESULTS: Common challenges persist which could be more strategically assessed and addressed. A quantifiable discrepancy entails personnel. The estimated radiation oncologists (ROs), nuclear medicine physicians (NMPs), and medical physicists (MPs for RT and nuclear medicine) per million inhabitants in the six collective countries respectively range between 2.69-38.00 ROs, 1.00-26.00 NMPs, and 0.30-3.45 MPs (Table 1), reflecting country-to-country inequities which largely match World Bank country-income stratifications. CONCLUSION: Established goals for RT and nuclear medicine advancement worldwide have proven elusive. The pace of progress could be hastened by enhanced approaches such as more sustainably phased implementation; better multinational networking to share lessons learned; routine quality and safety audits; as well as capacity building employing innovative, resource-sparing, cutting-edge technologic approaches. Bodies such as ministries of health, professional societies, and the IAEA shall serve critical roles in convening and coordinating more innovative RT and theranostics translational research, including expanding nuanced global database metrics to inform, reach, and potentiate milestones most meaningfully. POLICY SUMMARY: Aligned with WHO 25×25 NCDs target; WHA70.12 and WHA76.5 resolutions.

Association of Income Level and Ischemic Heart Disease: Potential Role of Walkability. / Associação de Nível de Renda e Doença Isquêmica do Coração: Papel Potencial da Caminhabilidade.

BACKGROUND: Association of Income Level and Ischemic Heart Disease: Potential Role of Walkability Association of ischemic heart disease (adjusted for traditional risk factors and socioeconomics variables) and income level (A), and walkability z-score (B), and association of walkability z-score and income level (C). BACKGROUND: Socioeconomic status has been linked to ischemic heart disease (IHD). High-income neighborhoods may expose individuals to a walking-promoting built environment for daily activities (walkability). Data from the association between income and IHD is lacking in middle-income countries. It is also uncertain whether walkability mediates this association. OBJECTIVES: To investigate whether income is associated with IHD in a middle-income country and whether neighborhood walkability mediates the income-IHD association. METHODS: This cross-sectional study evaluated 44,589 patients referred for myocardial perfusion imaging (SPECT-MPI). Income and walkability were derived from participants' residential census tract. Walkability quantitative score combined 4 variables: street connectivity, residential density, commercial density, and mixed land use. IHD was defined by abnormal myocardial perfusion during a SPECT-MPI study. We used adjusted mixed effects models to evaluate the association between income level and IHD, and we performed a mediation analysis to measure the percentage of the income-IHD association mediated by walkability. We considered p values below 0.01 as statistically significant. RESULTS: From 26,415 participants, those living in the lowest-income tertile census tract were more physically inactive (79.1% versus 75.8% versus 72.7%) when compared to higher-income tertile census tracts (p < 0.001). Income was associated with IHD (odds ratio: 0.91 [95% confidence interval: 0.87 to 0.96] for each 1,000.00 international dollars increase in income) for both men and women equally (p for interaction = 0.47). Census tracts with a higher income were associated with better walkability (p < 0.001); however, walkability did not mediate the income-IHD association (percent mediated = -0.3%). CONCLUSIONS: Income was independently associated with higher prevalence of IHD in a middle-income country irrespective of gender. Although walkability was associated with census tract income, it did not mediate the income-IHD association.

Prognostic parameters on baseline and interim [ 18 F]FDG-PET/computed tomography in diffuse large B-cell lymphoma patients.

OBJECTIVE: 2-[ 18 F]fluoro-2-deoxy- d -glucose PET/computed tomography ([ 18 F]FDG-PET/CT) is a widely used imaging method in the management of diffuse large B-cell lymphomas (DLBCL). Our aim was to investigate the prognostic performance of different PET biomarkers in a multicenter setting. METHODS: We investigated baseline volumetric values [metabolic tumor volume (MTV) and total lesion glycolysis (TLG), also normalized for body weight] segmented with three different methods [>SUV4 (glob4); 41% isocontour (41pc), and a gradient-based lesion growing algorithm (grad)] and interim parameters [Deauville score, maximal standardized uptake value (ΔSUVmax), modified qPET, and ratio PET (rPET)] alongside clinical parameters (stage, revised International Prognostic Index), using 24-month progression-free survival as the clinical endpoint. Receiver operating characteristics analyses were performed to define optimal cutoff points for the continuous PET parameters. RESULTS: A total of 107 diffuse large B-cell lymphoma patients were included (54 women; mean age: 53.7 years). MTV and TLG calculations showed good correlation among glob4, 41pc, and grad methods; however, optimal cutoff points were markedly different.Significantly different PFS was observed between low- and high-risk groups according to baseline MTV, body weight-adjusted (bwa) MTV, TLG, bwaTLG, as well as interim parameters Deauville score, ΔSUVmax, mqPET, and rPET. Univariate Cox regression analyses showed hazard ratios (HRs) lowest for bwaMTVglob4 (HR = 2.3) and highest for rPET (HR = 9.09). In a multivariate Cox-regression model, rPET was shown to be an independent predictor of PFS ( P = 0.041; HR = 9.15). Combined analysis showed that ΔSUVmax positive patients with high MTV formed a group with distinctly poor PFS (35.3%). CONCLUSION: Baseline MTV and TLG values and optimal cutoff points achieved with different segmentation methods varied markedly and showed a limited prognostic impact. Interim PET/CT parameters provided more accurate prognostic information with semiquantitative 'Deauville-like' parameters performing best in the present study.

Associação de Nível de Renda e Doença Isquêmica do Coração: Papel Potencial da Caminhabilidade / Association of Income Level and Ischemic Heart Disease: Potential Role of Walkability

Resumo Fundamento O nível socioeconômico tem sido associado à doença isquêmica do coração (DIC). Bairros de alta renda podem expor os indivíduos a um ambiente construído que promova caminhadas para atividades diárias (caminhabilidade). Faltam dados sobre a associação entre renda e DIC em países de renda média. Também é incerto se a caminhabilidade medeia essa associação. Objetivos Investigar se a renda está associada à DIC em um país de renda média e se a caminhabilidade dos bairros medeia a associação entre renda e DIC. Métodos O presente estudo transversal avaliou 44.589 pacientes encaminhados para imagem de perfusão miocárdica (SPECT-MPI). A renda e a caminhabilidade foram derivadas do setor censitário residencial dos participantes. A pontuação quantitativa da caminhabilidade combinou as seguintes 4 variáveis: conectividade viária, densidade residencial, densidade comercial e uso misto do solo. A DIC foi definida pela presença de perfusão miocárdica anormal durante um estudo SPECT-MPI. Utilizamos modelos ajustados com efeitos mistos para avaliar a associação entre nível de renda e DIC e realizamos uma análise de mediação para medir o percentual da associação entre renda e DIC mediada pela caminhabilidade. Consideramos valores de p abaixo de 0,01 como estatisticamente significativos. Resultados Dos 26.415 participantes, aqueles que residiam no setor censitário do tercil de menor renda eram mais fisicamente inativos (79,1% versus 75,8% versus 72,7%) quando comparados aos setores censitários do tercil de maior renda (p < 0,001). A renda foi associada à DIC (odds ratio: 0,91 [intervalo de confiança de 95%: 0,87 a 0,96] para cada aumento de 1000,00 dólares internacionais na renda), para homens e mulheres igualmente (p para interação = 0,47). Os setores censitários com maior renda estiveram associados a uma melhor caminhabilidade (p < 0,001); no entanto, a caminhabilidade não mediou a associação entre renda e DIC (porcentagem mediada = −0,3%). Conclusões A renda foi independentemente associada a maior prevalência de DIC em um país de renda média, independentemente de gênero. Embora a caminhabilidade tenha sido associada à renda do setor censitário, ela não mediou a associação entre renda e DIC.

Abstract Background Socioeconomic status has been linked to ischemic heart disease (IHD). High-income neighborhoods may expose individuals to a walking-promoting built environment for daily activities (walkability). Data from the association between income and IHD is lacking in middle-income countries. It is also uncertain whether walkability mediates this association. Objectives To investigate whether income is associated with IHD in a middle-income country and whether neighborhood walkability mediates the income-IHD association. Methods This cross-sectional study evaluated 44,589 patients referred for myocardial perfusion imaging (SPECT-MPI). Income and walkability were derived from participants' residential census tract. Walkability quantitative score combined 4 variables: street connectivity, residential density, commercial density, and mixed land use. IHD was defined by abnormal myocardial perfusion during a SPECT-MPI study. We used adjusted mixed effects models to evaluate the association between income level and IHD, and we performed a mediation analysis to measure the percentage of the income-IHD association mediated by walkability. We considered p values below 0.01 as statistically significant. Results From 26,415 participants, those living in the lowest-income tertile census tract were more physically inactive (79.1% versus 75.8% versus 72.7%) when compared to higher-income tertile census tracts (p < 0.001). Income was associated with IHD (odds ratio: 0.91 [95% confidence interval: 0.87 to 0.96] for each 1,000.00 international dollars increase in income) for both men and women equally (p for interaction = 0.47). Census tracts with a higher income were associated with better walkability (p < 0.001); however, walkability did not mediate the income-IHD association (percent mediated = −0.3%). Conclusions Income was independently associated with higher prevalence of IHD in a middle-income country irrespective of gender. Although walkability was associated with census tract income, it did not mediate the income-IHD association.

PSMA PET for the Evaluation of Liver Metastases in Castration-Resistant Prostate Cancer Patients: A Multicenter Retrospective Study.

Background: To evaluate the diagnostic performance of PSMA-PET compared to conventional imaging/liver biopsy in the detection of liver metastases in CRPC patients. Moreover, we evaluated a PSMA-PET/CT-based radiomic model able to identify liver metastases. Methods: Multicenter retrospective study enrolling patients with the following inclusion criteria: (a) proven CRPC patients, (b) PSMA-PET and conventional imaging/liver biopsy performed in a 6 months timeframe, (c) no therapy changes between PSMA-PET and conventional imaging/liver biopsy. PSMA-PET sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for liver metastases were calculated. After the extraction of radiomic features, a prediction model for liver metastases identification was developed. Results: Sixty CRPC patients were enrolled. Within 6 months before or after PSMA-PET, conventional imaging and liver biopsy identified 24/60 (40%) patients with liver metastases. PSMA-PET sensitivity, specificity, PPV, NPV, and accuracy for liver metastases were 0.58, 0.92, 0.82, 0.77, and 0.78, respectively. Either number of liver metastases and the maximum lesion diameter were significantly associated with the presence of a positive PSMA-PET (p < 0.05). On multivariate regression analysis, the radiomic feature-based model combining sphericity, and the moment of inverse difference (Idm), had an AUC of 0.807 (95% CI:0.686-0.920). Conclusion: For liver metastases assessment, [68Ga]Ga-PSMA-11-PET demonstrated moderate sensitivity while high specificity, PPV, and inter-reader agreement compared to conventional imaging/liver biopsy in CRPC patients.

Validation of Convolutional Neural Networks for Fast Determination of Whole-Body Metabolic Tumor Burden in Pediatric Lymphoma.

18F-FDG PET/CT quantification of whole-body tumor burden in lymphoma is not routinely performed because of the lack of fast methods. Although the semiautomatic method is fast, it is not fast enough to quantify tumor burden in daily clinical practice. Our purpose was to evaluate the performance of convolutional neural network (CNN) software in localizing neoplastic lesions in whole-body 18F-FDG PET/CT images of pediatric lymphoma patients. Methods: The retrospective image dataset, derived from the data pool of the International Atomic Energy Agency (coordinated research project E12017), included 102 baseline staging 18F-FDG PET/CT studies of pediatric lymphoma patients (mean age, 11 y). The images were quantified to determine the whole-body tumor burden (whole-body metabolic tumor volume [wbMTV] and whole-body total lesion glycolysis [wbTLG]) using semiautomatic software and CNN-based software. Both were displayed as semiautomatic wbMTV and wbTLG and as CNN wbMTV and wbTLG. The intraclass correlation coefficient (ICC) was applied to evaluate concordance between the CNN-based software and the semiautomatic software. Results: Twenty-six patients were excluded from the analysis because the software was unable to perform calculations for them. In the remaining 76 patients, CNN and semiautomatic wbMTV tumor burden metrics correlated strongly (ICC, 0.993; 95% CI, 0.989 - 0.996; P < 0.0001), as did CNN and semiautomatic wbTLG (ICC, 0.999; 95% CI, 0.998-0.999; P < 0.0001). However, the time spent calculating these metrics was significantly (<0.0001) less by CNN (mean, 19 s; range, 11-50 s) than by the semiautomatic method (mean, 21.6 min; range, 3.2-62.1 min), especially in patients with advanced disease. Conclusion: Determining whole-body tumor burden in pediatric lymphoma patients using CNN is fast and feasible in clinical practice.

Diagnostic Performance and Clinical Impact of 68Ga-PSMA-11 PET/CT Imaging in Early Relapsed Prostate Cancer After Radical Therapy: A Prospective Multicenter Study (IAEA-PSMA Study).

Biochemical recurrence (BCR) is a clinical challenge in prostate cancer (PCa) patients, as recurrence localization guides subsequent therapies. The use of PET with prostate-specific membrane antigen (PSMA) provides better accuracy than conventional imaging practice. This prospective, multicenter, international study was performed to evaluate the diagnostic performance and clinical impact of PSMA PET/CT for evaluating BCR in PCa patients in a worldwide scenario. Methods: Patients were recruited from 17 centers in 15 countries. Inclusion criteria were histopathologically proven prostate adenocarcinoma, previous primary treatment, clinically established BCR, and negative conventional imaging (CT plus bone scintigraphy) and MRI results for patients with PSA levels of 4-10 ng/mL. All patients underwent PET/CT scanning with 68Ga-PSMA-11. Images and data were centrally reviewed. Multivariate logistic regression analysis was applied to identify the independent predictors of PSMA-positive results. Variables were selected for this regression model on the basis of significant associations in the univariate analysis and previous clinical knowledge: Gleason score, the PSA level at the time of the PET scan, PSA doubling time, and primary treatment strategy. All patients were monitored for a minimum of 6 mo. Results: From a total of 1,004 patients, 77.7% were treated initially with radical prostatectomy and 22.3% were treated with radiotherapy. Overall, 65.1% had positive PSMA PET/CT results. PSMA PET/CT positivity was correlated with the Gleason score, PSA level at the time of the PET scan, PSA doubling time, and radiotherapy as the primary treatment (P < 0.001). Treatment was modified on the basis of PSMA PET/CT results in 56.8% of patients. PSMA PET/CT positivity rates were consistent and not statistically different among countries with different incomes. Conclusion: This multicenter, international, prospective trial of PSMA PET/CT confirmed its capability for detecting local and metastatic recurrence in most PCa patients in the setting of BCR. PSMA PET/CT positivity was correlated with the Gleason score, PSA level at the time of the PET scan, PSA doubling time, and radiotherapy as the primary treatment. PSMA PET/CT results led to changes in therapeutic management in more than half of the cohort. The study demonstrated the reliability and worldwide feasibility of PSMA PET/CT in the workup of PCa patients with BCR.

68Ga-Prostate-specific membrane antigen (PSMA) positron emission tomography (pet) in prostate cancer: a systematic review and meta-analysis

ABSTRACT Introduction: Prostate cancer (PC) is the second most commonly diagnosed cancer in males. 68Ga-PSMA PET/CT, a non-invasive diagnostic tool to evaluate PC with prostate-specific membrane antigen (PSMA) expression, has emerged as a more accurate alternative to assess disease staging. We aimed to identify predictors of positive 68Ga-PSMA PET and the accuracy of this technique. Materials and methods: Diagnostic accuracy cross-sectional study with prospective and retrospective approaches. We performed a comprehensive literature search on PubMed, Cochrane Library, and Embase database in search of studies including PC patients submitted to radical prostatectomy or radiotherapy with curative intent and presented biochemical recurrence following ASTRO 1996 criteria. A total of 35 studies involving 3910 patients submitted to 68-Ga-PSMA PET were included and independently assessed by two authors: 8 studies on diagnosis, four on staging, and 23 studies on restaging purposes. The significance level was α=0.05. Results: pooled sensitivity and specificity were 0.90 (0.86-0.93) and 0.90 (0.82-0.96), respectively, for diagnostic purposes; as for staging, pooled sensitivity and specificity were 0.93 (0.86-0.98) and 0.96 (0.92-0.99), respectively. In the restaging scenario, pooled sensitivity and specificity were 0.76 (0.74-0.78) and 0.45 (0.27-0.58), respectively, considering the identification of prostate cancer in each described situation. We also obtained specificity and sensitivity results for PSA subdivisions. Conclusion: 68Ga-PSMA PET provides higher sensitivity and specificity than traditional imaging for prostate cancer.

An international expert opinion statement on the utility of PET/MR for imaging of skeletal metastases.

BACKGROUND: MR is an important imaging modality for evaluating musculoskeletal malignancies owing to its high soft tissue contrast and its ability to acquire multiparametric information. PET provides quantitative molecular and physiologic information and is a critical tool in the diagnosis and staging of several malignancies. PET/MR, which can take advantage of its constituent modalities, is uniquely suited for evaluating skeletal metastases. We reviewed the current evidence of PET/MR in assessing for skeletal metastases and provided recommendations for its use. METHODS: We searched for the peer reviewed literature related to the usage of PET/MR in the settings of osseous metastases. In addition, expert opinions, practices, and protocols of major research institutions performing research on PET/MR of skeletal metastases were considered. RESULTS: Peer-reviewed published literature was included. Nuclear medicine and radiology experts, including those from 13 major PET/MR centers, shared the gained expertise on PET/MR use for evaluating skeletal metastases and contributed to a consensus expert opinion statement. [18F]-FDG and non [18F]-FDG PET/MR may provide key advantages over PET/CT in the evaluation for osseous metastases in several primary malignancies. CONCLUSION: PET/MR should be considered for staging of malignancies where there is a high likelihood of osseous metastatic disease based on the characteristics of the primary malignancy, hight clinical suspicious and in case, where the presence of osseous metastases will have an impact on patient management. Appropriate choice of tumor-specific radiopharmaceuticals, as well as stringent adherence to PET and MR protocols, should be employed.

68Ga-Prostate-specific membrane antigen (psma) positron emission tomography (pet) in prostate cancer: a systematic review and meta-analysis.

INTRODUCTION: Prostate cancer (PC) is the second most commonly diagnosed cancer in males. 68Ga-PSMA PET/CT, a non-invasive diagnostic tool to evaluate PC with prostate-specific membrane antigen (PSMA) expression, has emerged as a more accurate alternative to assess disease staging. We aimed to identify predictors of positive 68Ga-PSMA PET and the accuracy of this technique. MATERIALS AND METHODS: Diagnostic accuracy cross-sectional study with prospective and retrospective approaches. We performed a comprehensive literature search on PubMed, Cochrane Library, and Embase database in search of studies including PC patients submitted to radical prostatectomy or radiotherapy with curative intent and presented biochemical recurrence following ASTRO 1996 criteria. A total of 35 studies involving 3910 patients submitted to 68-Ga-PSMA PET were included and independently assessed by two authors: 8 studies on diagnosis, four on staging, and 23 studies on restaging purposes. The significance level was α=0.05. RESULTS: pooled sensitivity and specificity were 0.90 (0.86-0.93) and 0.90 (0.82-0.96), respectively, for diagnostic purposes; as for staging, pooled sensitivity and specificity were 0.93 (0.86-0.98) and 0.96 (0.92-0.99), respectively. In the restaging scenario, pooled sensitivity and specificity were 0.76 (0.74-0.78) and 0.45 (0.27-0.58), respectively, considering the identification of prostate cancer in each described situation. We also obtained specificity and sensitivity results for PSA subdivisions. CONCLUSION: 68Ga-PSMA PET provides higher sensitivity and specificity than traditional imaging for prostate cancer.

PET/CT-Guided Biopsy of Suspected Lung Lesions Requires Less Rebiopsy Than CT-Guided Biopsy Due to Inconclusive Results.

The purpose of this study was to compare 18F-FDG PET/CT and CT performance in guiding percutaneous biopsies with histologic confirmation of lung lesions. Methods: We prospectively evaluated 341 patients, of whom 216 underwent 18F-FDG PET/CT-guided biopsy and 125 underwent CT-guided biopsy. The pathology results, lesion size, complications, and rebiopsy rate in the 2 groups were evaluated. Results: Of the 216 biopsies with PET/CT guidance, histology demonstrated 170 lesions (78.7%) to be malignant and 46 (21.3%) to be benign. In the CT-guided group, of 125 lesions, 77 (61.6%) were malignant and 48 (38.4%) were benign (P = 0.001). Inconclusive results prompted the need for a second biopsy in 18 patients: 13 of 125 (10.4%) in the CT group and 5 of 216 (2.3%) in PET group (P = 0.001). Complications were pneumothorax (13.2%), hemothorax (0.8%), and hemoptysis (0.6%). No life-threatening adverse events or fatalities were reported. The difference in complication rates between the 2 groups was not significant (P = 0.6). Malignant lesions showed a greater mean size than benign lesions regardless of the group (P = 0.015). Conclusion: PET/CT-guided biopsy of lung lesions led to fewer inconclusive biopsies than CT-guided biopsy, with similar complication rates.

Practice and prospects for PET/CT guided interventions.

During the past 10 years, performing real-time molecular imaging with positron emission tomography (PET) in combination with computed tomography (CT) during interventional procedures has undergone rapid development. Keeping in mind the interest of the nuclear medicine readers, an update is provided of the current workflows using real-time PET/CT in percutaneous biopsies and tumor ablations. The clinical utility of PET/CT guided biopsies in cancer patients with lung, liver, lymphoma, and bone tumors are reviewed. Several technological developments, including the introduction of new PET tracers and robotic arms as well as opportunities provided through acquiring radioactive biopsy specimens are briefly reviewed.

Radiation exposure after myocardial perfusion imaging with Cadmium-Zinc-Telluride camera versus conventional camera.

BACKGROUND: Patient exposure to radiation during the management of coronary heart disease (CHD) can be reduced with more efficient technologies in nuclear medicine, such as the Cadmium-Zinc-Telluride (CZT) gamma-camera for myocardial perfusion imaging (MPI) studies. However, it has been suggested that CZT has lower specificity, which might lead to more downstream radiological procedures, particularly among obese individuals. METHODS AND RESULTS: We evaluated 244 patients with suspected CHD who underwent CZT-SPECT and matched 1:1 according to sex, age, and body mass index (BMI) with those undergoing MPI study with the Anger gamma-camera (Anger-SPECT). The outcome was the total radiation exposure from the MPI study added to the radiation exposure from all subsequent cardiac examinations during a 90-day follow-up. The total radiation dose after 90 days was significantly lower in the CZT-SPECT group (6.4 ± 4.8 vs 9.5±4.9 mSv, P < .001). After adjusting for potential confounders, CZT-SPECT remained associated with lower total radiation dose, but it significantly attenuated among obese individuals (Beta coefficient - 3.73 ± 0.86 for BMI < 30 vs - 2.30 ± 0.92 for BMI ≥ 30 Kg/m2, P for interaction < 0.032). CONCLUSIONS: CZT-SPECT was associated with lower total radiation doses compared to Anger-SPECT, albeit this benefit may be attenuated in obese individuals.

Global Impact of COVID-19 on Nuclear Medicine Departments: An International Survey in April 2020.

The coronavirus disease 2019 (COVID-19) pandemic has placed significant challenges on health-care systems worldwide, whether in the preparation, response, or recovery phase of the pandemic. This has been primarily managed by dramatically reducing in- and outpatient services for other diseases and implementing infection prevention and control measures. The impact of the pandemic on nuclear medicine departments and their services has not yet been established. The aim of this online survey was to evaluate the impact of COVID-19 on nuclear medicine departments. Methods: A web-based questionnaire, made available from April 16 to May 3, 2020, was designed to determine the impact of the pandemic on in- and outpatient nuclear medicine departments, including the number of procedures, employee health, availability of radiotracers and other essential supplies, and availability of personal protective equipment. The survey also inquired about operational aspects and types of facilities as well as other challenges. Results: A total of 434 responses from 72 countries were registered and analyzed. Respondents reported an average decline of 54% in diagnostic procedures. PET/CT scans decreased by an average of 36%, whereas sentinel lymph-node procedures decreased by 45%, lung scans by 56%, bone scans by 60%, myocardial studies by 66%, and thyroid studies by 67%. Of all participating centers, 81% performed radionuclide therapies, and they reported a reduction of 45% on average in the last 4 wk, ranging from over 76% in Latin America and South East Asia to 16% in South Korea and Singapore. Survey results showed that 52% of participating sites limited their 99mTc/99Mo generator purchases, and 12% of them temporarily cancelled orders. Insufficient supplies of essential materials (radioisotopes, generators, and kits) were reported, especially for 99mTc/99Mo generators and 131I, particularly in Africa, Asia, and Latin America. Conclusion: Both diagnostic and therapeutic nuclear medicine procedures declined precipitously, with countries worldwide being affected by the pandemic to a similar degree. Countries that were in the postpeak phase of the pandemic when they responded to the survey, such as South Korea and Singapore, reported a less pronounced impact on nuclear medicine services; however, the overall results of the survey showed that nuclear medicine services worldwide had been significantly impacted. In relation to staff health, 15% of respondents experienced COVID-19 infections within their own departments.

Validation of a Multifocal Segmentation Method for Measuring Metabolic Tumor Volume in Hodgkin Lymphoma.

Quantification of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) can be time-consuming. We evaluated the performance of an automatic multifocal segmentation (MFS) method of quantification in patients with different stages of Hodgkin lymphoma, using the multiple VOI (MV) method as reference. Methods: This prospective bicentric study included 50 patients with Hodgkin lymphoma who underwent staging 18F-FGD PET/CT. The examinations were centrally reviewed and processed with commercial MFS software to obtain MTV and TLG using 2 fixed relative thresholds (40% and 20% of SUVmax) for each lesion. All PET/CT scans were processed using the MV and MFS methods. Interclass correlation coefficients and Bland-Altman plots were used for statistical analysis. Repeated calculations of MTV and TLG values by 2 observers with different degrees of PET/CT imaging experience were used to ascertain interobserver agreement on the MFS method. Results: The means and SDs obtained for the MTV with MV and MFS were, respectively, 736 ± 856 mL and 660 ± 699 mL for the 20% threshold and 313 ± 359 mL and 372 ± 434 mL for the 40% threshold. The time spent calculating the MTV was much shorter with the MFS method than with the MV method (median time, 11.6 min [range, 1-30 min] and 64.4 min [range, 1-240 min], respectively), especially in patients with advanced disease. Time spent was similar in patients with localized disease. There were no statistical differences between the MFS values obtained by the 2 different observers. Conclusion: MTV and TLG calculations using MFS are reproducible, generate similar results to those obtained with MV, and are much less timing-consuming. Main differences between the 2 methods were related to difficulties in avoiding overlay of VOIs in the MV technique. MV and MFS perform equally well in patients with a small number of lesions.

Combined Visual and Semiquantitative Evaluation Improves Outcome Prediction by Early Midtreatment 18F-FDG PET in Diffuse Large B-Cell Lymphoma.

The purpose of this study was to assess the predictive and prognostic value of interim FDG PET (iPET) in evaluating early response to immunochemotherapy after 2 cycles (PET-2) in diffuse large B-cell lymphoma (DLBCL) by applying 2 different methods of interpretation: the Deauville visual 5-point scale (5-PS) and a change in SUV (ΔSUV) by semiquantitative evaluation. Methods: In total, 145 patients with newly diagnosed DLBCL underwent pretreatment PET and PET-2 assessment. PET-2 was classified according to both 5-PS and percentage ΔSUV. Receiver-operating-characteristic analysis was performed to compare the accuracy of the 2 methods for predicting progression-free survival. Survival estimates, based on each method separately and combined, were calculated for iPET-positive (iPET+) and iPET-negative (iPET-) groups and compared. Results: Both with 5-PS and with ΔSUV-based evaluations, significant differences were found between the progression-free survival of iPET- and iPET+ patient groups (P < 0.001). Visually, the best negative predictive value (NPV) and positive predictive value (PPV) occurred when iPET was defined as positive if the Deauville score was 4-5 (89% and 59%, respectively). Using the 66% ΔSUV cutoff reported previously, NPV and PPV were 80% and 76%, respectively. ΔSUV at the 48.9% cutoff, reported for the first time here, produced 100% specificity along with the highest sensitivity (24%). The 5-PS and a semiquantitative ΔSUV of less than 48.9% for each PET-2 gave the same PET-2 classification (positive or negative) in 70% (102/145) of all patients. This combined classification delivered NPV and PPV of 89% and 100%, respectively, and all iPET+ patients failed to achieve or remain in remission. Conclusion: In this large consistently treated and assessed series of DLBCL patients, iPET had good prognostic value interpreted either visually or semiquantitatively. We determined that the most effective ΔSUV cutoff was 48.9% and that when combined with 5-PS assessment, a positive PET-2 result was highly predictive of treatment failure.

Is True Whole-Body 18F-FDG PET/CT Required in Pediatric Lymphoma? An IAEA Multicenter Prospective Study.

Guidelines recommend true whole-body 18F-FDG PET/CT scans from vertex to toes in pediatric lymphoma patients, although this suggestion has not been validated in large clinical trials. The objective of the study was to evaluate the incidence and clinical impact of lesions outside the "eyes to thighs" regular field of view (R-FOV) in 18F-FDG PET/CT staging (sPET) and interim (iPET) scans in pediatric lymphoma patients. Methods: True whole-body sPET and iPET scans were prospectively obtained in pediatric lymphoma patients (11 worldwide centers). Expert panel central review of sPET and iPET scans were evaluated for lymphoma lesions outside the R-FOV and clinical relevance of these findings. Results: A total of 610 scans were obtained in 305 patients. The sPET scans did not show lesions outside the R-FOV in 91.8% of the patients, whereas in 8.2% patients the sPET scans demonstrated lesions also outside the R-FOV (soft tissue, bone, bone marrow, and skin); however, the presence of these lesions did not change the clinical stage of any patient and did not affect treatment decision. Among the 305 iPET scans, there were no new positive 18F-FDG-avid lesions outside the R-FOV, when compared with their paired sPET scans. A single lesion outside the R-FOV on iPET occurred in 1 patient (0.3%), with the primary lesion diagnosed in the femur on sPET that persisted on iPET. Conclusion: The identification of additional lesions outside the R-FOV (eyes to thighs) using 18F-FDG PET/CT has no impact in the definition of the clinical stage of disease and minimal impact in the treatment definition of patients with pediatric lymphoma. As so, R-FOV for both sPET and iPET scans could be performed.

Fluorodeoxyglucose-positron emission tomography staging can replace bone marrow biopsy in Hodgkin's lymphoma. Results from Brazilian Hodgkin's Lymphoma Study Group

ABSTRACT Objective: To investigate, in a large prospective multicenter study, whether 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography is sufficiently accurate to identify clinically important bone marrow involvement by Hodgkin's lymphoma to replace routine bone marrow biopsy in a developing tropical country. Methods: Patients newly diagnosed with Hodgkin's lymphoma were recruited from six cancer centers in Brazil. All were staged by the results of positron emission tomography/computed tomography that were centrally reviewed and by iliac crest bone marrow biopsy. Patients were classified as having marrow disease if they had lymphoma identified by marrow biopsy histology or had focal 2-[18F]-fluoro-2-deoxy-D-glucose marrow uptake that resolved following chemotherapy. Results: A total of 246 participants were recruited from six different centers and 62 (25.2%) were judged to have Hodgkin's lymphoma in the bone marrow. Positron emission tomography and biopsies were concordant in 206 patients (83%). Positron emission tomography correctly identified marrow disease in 59/62 patients (95.1%) and marrow biopsy in 25/62 patients (40.3%). In 22/62 (35.4%) patients, the two techniques were concordant in the diagnosis of marrow involvement. Of the forty discordant results, positron emission tomography found bone marrow involvement in 37 patients, upstaging 22 to stage IV and having an impact on therapeutic decision in nine cases given their reallocation from early to advanced stage. Three false negative positron emission tomography results were obtained with bone marrow biopsy giving positive findings. All three cases were classified as stage IV regardless of bone marrow findings implying no modification in the clinical management. The sensitivity, specificity and accuracy of positron emission tomography for detecting bone marrow disease were 95%, 100% and 98% and for bone marrow biopsy they were 40%, 100% and 84%, respectively. Conclusion: We conclude that positron emission tomography can replace marrow biopsy in Brazilian patients with Hodgkin's lymphoma without compromising clinical management.