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Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) are both malignancies originating in the lymphatic system and both affect children, but many features differ considerably, impacting workup and management. This paper provides consensus-based imaging recommendations for evaluation of patients with HL and NHL at diagnosis and response assessment for both interim and end of therapy (follow-up)., (© 2022 Wiley Periodicals LLC.)

18 F-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 18 F-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 18 F-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., (© 2022 by the Society of Nuclear Medicine and Molecular Imaging.)

Guidelines recommend true whole-body 18 F-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 18 F-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 18 F-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 18 F-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., (© 2019 by the Society of Nuclear Medicine and Molecular Imaging.)

Interim and end-of-treatment PET/CT have become central to the evaluation of Hodgkin and non-Hodgkin lymphoma. This review article seeks to aid clinical decision making by providing an overview of available data on the diagnostic and prognostic value of PET/CT imaging for response assessment and pretransplant evaluation in lymphoma. The relative strengths and limitations of these techniques in various disease subtypes and clinical scenarios are explored, along with their current standards for reporting and latest developments. Particular attention is given to response-adapted therapy, which is emerging as a cornerstone of clinical management., (© 2017 by the Society of Nuclear Medicine and Molecular Imaging.)

The effectiveness of cancer therapy, both in individual patients and across populations, requires a systematic and reproducible method for evaluating response to treatment. Early efforts to meet this need resulted in the creation of numerous guidelines for quantifying posttherapy changes in disease extent, both anatomically and metabolically. Over the past few years, criteria for disease response classification have been developed for specific cancer histologies. To date, the spectrum of disease broadly referred to as lymphoma is perhaps the most common for which disease response classification is used. This review article provides an overview of the existing response assessment criteria for lymphoma and highlights their respective methodologies and validities. Concerns over the technical complexity and arbitrary thresholds of many of these criteria, which have impeded the long-standing endeavor of standardizing response assessment, are also discussed., (© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

Many pediatric centers are beginning to accumulate a large experience in the use of thallium-201 (201Tl) imaging with 201Tl requires a state-of-the-art high-resolution gamma camera computer system with single photon emission computed tomography (SPECT) capability and a physician-directed tailored examination. Tumor imaging with 201Tl, with its multifactorial localization mechanisms that are different from those for gallium-67, offers a distinct advantage over gallium tumor imaging with a short total imaging time. Tumors are variable in avidity and intensity of thallium uptake. Primary and metastatic disease can be detected with 201Tl scintigraphy. Baseline pretreatment determination of thallium avidity is crucial to its efficacy in therapeutic response assessment. Adjunctive SPECT imaging provides greater sensitivity for lesion detection and direct comparison of physiology (thallium uptake) with anatomy (computed tomography and magnetic resonance imaging). The sensitivity and specificity for detection of pediatric brain tumors has been reported as 77% and 93%, respectively. Thallium-201 brain SPECT also provides a less expensive and more readily available alternative to positron emission tomography for assessing the functional state of pediatric brain tumors. Extremity osteogenic sarcoma and Ewing's sarcoma have 100% sensitivity for 201Tl uptake pretreatment. Early results confirm an association between 201Tl uptake and histological tumor response. The determination of residual/recurrent disease versus thymic rebound and other nonneoplastic change in thallium-avid lymphoma, rhabdomyosarcoma, and germ cell tumors that involve the thorax can be confirmed with a 201Tl SPECT examination. Soft-tissue tumors elsewhere in the body may be detected with 201Tl scintigraphy. Thallium-201 does not exhibit 100% specificity for tumors. False-positive 201Tl uptake has been seen in histiocytosis X, benign bone tumors, stress fractures, and inflammation.

Kaposi sarcoma and malignant lymphoma were successfully imaged with high purity liposomes containing indium-111 in two patients with AIDS. Gamma camera images of the patient with Kaposi sarcoma showed four discrete lesions along the left foot and calf with no foci along the right foot, and no uptake into clinically enlarged but non-neoplastic lymph nodes. The spread of the Kaposi sarcoma was proximal along the leg. The neoplastic cervical lymph nodes in the second patient who had large-cell diffuse intermediate grade lymphoma were also imaged successfully. Since Kaposi sarcoma and lymphoma frequently involve occult sites, liposome imaging may prove useful in the diagnosis and management of these diseases.