The evidence-based role of catecholaminergic PET tracers in Neuroblastoma. A systematic review and a head-to-head comparison with mIBG scintigraphy.

BACKGROUND: Molecular imaging is pivotal in staging and response assessment of children with neuroblastoma (NB). [123I]-metaiodobenzylguanidine (mIBG) is the standard imaging method; however, it is characterised by low spatial resolution, time-consuming acquisition procedures and difficult interpretation. Many PET catecholaminergic radiotracers have been proposed as a replacement for [123I]-mIBG, however they have not yet made it into clinical practice. We aimed to review the available literature comparing head-to-head [123I]-mIBG with the most common PET catecholaminergic radiopharmaceuticals. METHODS: We searched the PubMed database for studies performing a head-to-head comparison between [123I]-mIBG and PET radiopharmaceuticals including meta-hydroxyephedrine ([11C]C-HED), 18F-18F-3,4-dihydroxyphenylalanine ([18F]DOPA) [124I]mIBG and Meta-[18F]fluorobenzylguanidine ([18F]mFBG). Review articles, preclinical studies, small case series (< 5 subjects), case reports, and articles not in English were excluded. From each study, the following characteristics were extracted: bibliographic information, technical parameters, and the sensitivity of the procedure according to a patient-based analysis (PBA) and a lesion-based analysis (LBA). RESULTS: Ten studies were selected: two regarding [11C]C-HED, four [18F]DOPA, one [124I]mIBG, and three [18F]mFBG. These studies included 181 patients (range 5-46). For the PBA, the superiority of the PET method was reported in two out of ten studies (both using [18F]DOPA). For LBA, PET detected significantly more lesions than scintigraphy in seven out of ten studies. CONCLUSIONS: PET/CT using catecholaminergic tracers shows superior diagnostic performance than mIBG scintigraphy. However, it is still unknown if such superiority can influence clinical decision-making. Nonetheless, the PET examination appears promising for clinical practice as it offers faster image acquisition, less need for sedation, and a single-day examination.

Comparison of the different imaging modalities used to image pediatric oncology patients: A COG diagnostic imaging committee/SPR oncology committee white paper.

Diagnostic imaging is essential in the diagnosis and management, including surveillance, of known or suspected cancer in children. The independent and combined roles of the various modalities, consisting of radiography, fluoroscopy, ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine (NM), are both prescribed through protocols but also function in caring for complications that may occur during or subsequent to treatment such as infection, bleeding, or organ compromise. Use of a specific imaging modality may be based on situational circumstances such as a brain CT or MR for a new onset seizure, chest CT for respiratory signs or symptoms, or US for gross hematuria. However, in many situations, there are competing choices that do not easily lend themselves to a formulaic approach as options; these situations depend on the contributions of a variety of factors based on a combination of the clinical scenario and the strengths and limitations of the imaging modalities. Therefore, an improved understanding of the potential influence of the imaging decision pathways in pediatric cancer care can come from comparison among the individual diagnostic imaging modalities. The purpose of the following material to is to provide such a comparison. To do this, pediatric imaging content experts for the individual modalities of radiography and fluoroscopy, US, CT, MRI, and NM will discuss the individual modality strengths and limitations.

Imaging recommendations in pediatric lymphoma: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

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).

Imaging of pediatric bone tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

Malignant primary bone tumors are uncommon in the pediatric population, accounting for 3%-5% of all pediatric malignancies. Osteosarcoma and Ewing sarcoma comprise 90% of malignant primary bone tumors in children and adolescents. This paper provides consensus-based recommendations for imaging in children with osteosarcoma and Ewing sarcoma at diagnosis, during therapy, and after therapy.

Ifosfamide, gemcitabine, and vinorelbine is an effective salvage regimen with excellent stem cell mobilization in relapsed or refractory pediatric Hodgkin lymphoma.

We describe 12 pediatric patients (8-16 years) with primary refractory (N = 6) or first relapse (N = 6) Hodgkin lymphoma (HL) treated with ifosfamide, gemcitabine, and vinorelbine (IGEV). The overall response rate to IGEV was 100%, with seven (58%) complete responses (CR) and five (42%) partial responses. Successful CD34+ stem cell mobilization was achieved in all patients. Following subsequent autologous stem cell transplantation, 10 patients (83%) achieved CR. At a median follow-up of 71 months, 11 patients had no evidence of disease. Five-year second event-free survival and overall survival were 83% ± 11.0% and 90.0% ± 9.5%, respectively. IGEV is an effective salvage regimen for children with relapsed/refractory HL.

The Utility of PET/CT in Guiding Radiotherapy Reduction for Children With Hodgkin Lymphoma Treated With ABVD.

ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) is standard upfront chemotherapy for adults diagnosed with Hodgkin lymphoma (HL), but positron emission tomography (PET)-based response data following ABVD is lacking for pediatrics. Among children who received ABVD for HL, we document interim and end of therapy PET-computed tomography (CT) response by Deauville criteria, and survival outcomes following a response-based reduction in involved field radiotherapy (IFRT). Children 18 years of age or below with HL treated with ABVD between 2006 and 2015 who had interim PET/CT scans after 2 cycles of chemotherapy were included. Interim and end of therapy PET/CT scans were retrospectively re-evaluated using Deauville criteria by 3 radiologists. Among 45 children, 32 (71%) met criteria for intermediate risk, 86% achieved rapid early response (RER) and only 4 (9%) received upfront IFRT. Patients achieving RER had superior 5-year event-free survival (EFS) 95%±4% versus 50%±18% (P≤0.001) and overall survival (OS) 100% versus 83%±15% (P=0.025). Patients with bulk who achieved RER and received no IFRT achieved 5-year EFS of 92%±6% and OS 100%. Low, intermediate, and high risk patients had 5-year EFS of 100%, 94%±4%, and 50%±18% (P=0.002) and 5-year OS of 100%, 100%, and 75%±15% (P=0.03). RER following 2 cycles of ABVD is predictive of survival outcomes in children and adolescents with HL and may identify a group who may omit IFRT.

Imaging for diagnosis, staging and response assessment of Hodgkin lymphoma and non-Hodgkin lymphoma.

Hodgkin lymphoma and non-Hodgkin lymphoma are common malignancies in children and are now highly treatable. Imaging plays a major role in diagnosis, staging and response using conventional CT and MRI and metabolic imaging with positron emission tomography (PET)/CT and PET/MRI. Cross-sectional imaging has replaced staging laparotomy and splenectomy by demonstrating abdominal nodal groups and organ involvement. [F-18]2-fluoro-2-deoxyglucose (FDG) PET provides information on bone marrow involvement, and MRI elucidates details of cortical bone and confirmation of bone marrow involvement. The staging system for Hodgkin lymphoma is the Ann Arbor system with Cotswald modifications and is based on imaging, whereas the non-Hodgkin staging system is the St. Jude Classification by Murphy or the more recent revised International Pediatric Non-Hodgkin Lymphoma Staging System (IPNHLSS). Because all pediatric lymphomas are metabolically FDG-avid and identify all nodal, solid organ, cortical bone and bone marrow disease, staging evaluations require FDG PET as PET/CT or PET/MRI in both Hodgkin and non-Hodgkin lymphoma. Both diseases have in common issues of airway compromise at presentation demonstrated by imaging. Differences exist in that Hodgkin lymphoma has several independent poor prognostic factors seen by imaging such as large mediastinal adenopathy, Stage IV disease, systemic symptoms, pleural effusion and pericardial effusion. Non-Hodgkin lymphoma includes more organ involvement such as renal, ovary, central nervous system and skin. Early or interim PET-negative scans are a reliable indicator of improved clinical outcome and optimize risk-adapted therapy and patient management; imaging may not, however, predict who will relapse. A recent multicenter trial has concluded that it is usually sufficient for pediatric lymphoma at staging and interim assessment to evaluate children with PET imaging from skull base to mid-thigh. Various systems of assessment of presence of disease or response are used, including the Deauville visual scale, where avidity is compared to liver; Lugano, which includes size change as part of response; or quantitative PET, which uses standardized uptake values to define more accurate response. Newer methods of immunotherapy can produce challenges in FDG PET evaluation because of inflammatory changes that may not represent disease.

Guidelines on nuclear medicine imaging in neuroblastoma.

Nuclear medicine has a central role in the diagnosis, staging, response assessment and long-term follow-up of neuroblastoma, the most common solid extracranial tumour in children. These EANM guidelines include updated information on 123I-mIBG, the most common study in nuclear medicine for the evaluation of neuroblastoma, and on PET/CT imaging with 18F-FDG, 18F-DOPA and 68Ga-DOTA peptides. These PET/CT studies are increasingly employed in clinical practice. Indications, advantages and limitations are presented along with recommendations on study protocols, interpretation of findings and reporting results.

Validation of the mIBG skeletal SIOPEN scoring method in two independent high-risk neuroblastoma populations: the SIOPEN/HR-NBL1 and COG-A3973 trials.

BACKGROUND: Validation of the prognostic value of the SIOPEN mIBG skeletal scoring system in two independent stage 4, mIBG avid, high-risk neuroblastoma populations. RESULTS: The semi-quantitative SIOPEN score evaluates skeletal meta-iodobenzylguanidine (mIBG) uptake on a 0-6 scale in 12 anatomical regions. Evaluable mIBG scans from 216 COG-A3973 and 341 SIOPEN/HR-NBL1 trial patients were reviewed pre- and post-induction chemotherapy. The prognostic value of skeletal scores for 5-year event free survival (5 yr.-EFS) was tested in the source and validation cohorts. At diagnosis, both cohorts showed a gradual non-linear increase in risk with cumulative scores. Several approaches were explored to test the relationship between score and EFS. Ultimately, a cutoff score of ≤3 was the most useful predictor across trials. A SIOPEN score ≤ 3 pre-induction was found in 15% SIOPEN patients and in 22% of COG patients and increased post-induction to 60% in SIOPEN patients and to 73% in COG patients. Baseline 5 yr.-EFS rates in the SIOPEN/HR-NBL1 cohort for scores ≤3 were 47% ± 7% versus 26% ± 3% for higher scores at diagnosis (p < 0.007) and 36% ± 4% versus 14% ± 4% (p < 0.001) for scores obtained post-induction. The COG-A3973 showed 5 yr.-EFS rates for scores ≤3 of 51% ± 7% versus 34% ± 4% for higher scores (p < 0.001) at diagnosis and 43% ± 5% versus 16% ± 6% (p = 0.004) for post-induction scores. Hazard ratios (HR) significantly favoured patients with scores ≤3 after adjustment for age and MYCN-amplification. Optimal outcomes were recorded in patients who achieved complete skeletal response. CONCLUSIONS: Validation in two independent cohorts confirms the prognostic value of the SIOPEN skeletal score. In particular, patients with an absolute SIOPEN score > 3 after induction have very poor outcomes and should be considered for alternative therapeutic strategies.

Computer-assisted Curie scoring for metaiodobenzylguanidine (MIBG) scans in patients with neuroblastoma.

BACKGROUND: Radiolabeled metaiodobenzylguanidine (MIBG) is sensitive and specific for detecting neuroblastoma. The extent of MIBG-avid disease is assessed using Curie scores. Although Curie scoring is prognostic in patients with high-risk neuroblastoma, there is no standardized method to assess the response of specific sites of disease over time. The goal of this study was to develop approaches for Curie scoring to facilitate the calculation of scores and comparison of specific sites on serial scans. PROCEDURE: We designed three semiautomated methods for determining Curie scores, each with increasing degrees of computer assistance. Method A was based on visual assessment and tallying of MIBG-avid lesions. For method B, scores were tabulated from a schematic that associated anatomic regions to MIBG-positive lesions. For method C, an anatomic mesh was used to mark MIBG-positive lesions with automatic assignment and tallying of scores. Five imaging physicians experienced in MIBG interpretation scored 38 scans using each method, and the feasibility and utility of the methods were assessed using surveys. RESULTS: There was good reliability between methods and observers. The user-interface methods required 57 to 110 seconds longer than the visual method. Imaging physicians indicated that it was useful that methods B and C enabled tracking of lesions. Imaging physicians preferred method B to method C because of its efficiency. CONCLUSIONS: We demonstrate the feasibility of semiautomated approaches for Curie score calculation. Although more time was needed for strategies B and C, the ability to track and document individual MIBG-positive lesions over time is a strength of these methods.

Nivolumab in the Treatment of Refractory Pediatric Hodgkin Lymphoma.

The programmed death-1 (PD-1) pathway of immune evasion is exploited by many malignancies to limit host T-cell-mediated immune responses. Nivolumab is a PD-1-blocking monoclonal antibody that disrupts this pathway and is FDA approved for the treatment of metastatic melanoma, renal cell carcinoma, and squamous non-small cell lung cancer. In this case report, we describe the first published pediatric experience of nivolumab in refractory classic Hodgkin lymphoma. In this patient with primary refractory disease and high disease burden, cytokine release syndrome requiring inotropic support developed following the first infusion of nivolumab. The patient subsequently demonstrated a dramatic clinical response with resolution of fevers, transfusion independence, improvement in functional status, and very good partial response on PET/CT following a single dose. Nivolumab was continued with corticosteroid and antihistamine premedication without further adverse events and clinical benefit was sustained at 11 months after therapy initiation, despite evidence of slow radiographic disease progression.

Peritoneal-pericardial communication in an adolescent on peritoneal dialysis.

BACKGROUND: Dialysate leakage into the pericardium is a rare but potentially life-threatening complication of peritoneal dialysis (PD). There has been one reported pediatric case of spontaneous peritoneo-pericardial fistula in a 2-year-old boy with tissue fragility due to malnutrition and two reported adult cases in PD patients with a history of previous cardiac surgery and/or pericardiocentesis. CASE-DIAGNOSIS/TREATMENT: We describe a 15-year-old girl with end-stage renal disease secondary to granulomatosis with polyangiitis, with recurrent pericardial effusions secondary to a peritoneo-pericardial fistula while on continuous cycling peritoneal dialysis (CCPD). She had previously presented with chylous pericardial effusion that required pericardiocentesis and subsequently developed recurrent pericardial effusions when she was commenced on CCPD 9 months later. Pericardial fluid chemistry revealed a sterile, serous fluid containing 15.1 mmol/L of glucose and <0.11 mmol/L of triglycerides. Peritoneal scintigraphy with Tc-99m labeled sulfur colloid injected intra-peritoneally confirmed the presence of a peritoneo-pericardial fistula. The pericardial effusions resolved upon switching the patient to hemodialysis (HD). CONCLUSIONS: Our case of recurrent pericardial effusions in a child on PD secondary to a peritoneo-pericardial fistula highlights the need for close follow-up in patients with a history of previous pericardiocentesis who are commenced on PD.

Common normal variants of pediatric vertebral development that mimic fractures: a pictorial review from a national longitudinal bone health study.

Children with glucocorticoid-treated illnesses are at risk for osteoporotic vertebral fractures, and growing awareness of this has led to increased monitoring for these fractures. However scant literature describes developmental changes in vertebral morphology that can mimic fractures. The goal of this paper is to aid in distinguishing between normal variants and fractures. We illustrate differences using lateral spine radiographs obtained annually from children recruited to the Canada-wide STeroid-Associated Osteoporosis in the Pediatric Population (STOPP) observational study, in which 400 children with glucocorticoid-treated leukemia, rheumatic disorders, and nephrotic syndrome were enrolled near glucocorticoid initiation and followed prospectively for 6 years. Normal variants mimicking fractures exist in all regions of the spine and fall into two groups. The first group comprises variants mimicking pathological vertebral height loss, including not-yet-ossified vertebral apophyses superiorly and inferiorly, which can lead to a vertebral shape easily over-interpreted as anterior wedge fracture, physiological beaking, or spondylolisthesis associated with shortened posterior vertebral height. The second group includes variants mimicking other radiologic signs of fractures: anterior vertebral artery groove resembling an anterior buckle fracture, Cupid's bow balloon disk morphology, Schmorl nodes mimicking concave endplate fractures, and parallax artifact resembling endplate interruption or biconcavity. If an unexpected vertebral body contour is detected, careful attention to its location, detailed morphology, and (if available) serial changes over time may clarify whether it is a fracture requiring change in management or simply a normal variant. Awareness of the variants described in this paper can improve accuracy in the diagnosis of pediatric vertebral fractures.

SPECT/CT in pediatric patient management.

Hybrid SPECT/CT imaging is becoming the standard of care in pediatric imaging. Indications are mainly for oncologic imaging including mIBG scintigraphy for neuroblastoma and I-123 post surgical imaging of children with thyroid carcinoma, bone scintigraphy for back pain, children referred from sports medicine and neurodevelopmentally delayed children presenting with pain symptoms. The studies provide improved diagnostic accuracy, and oncologic imaging that includes optimized CT as part of the SPECT/CT study may decrease the number of studies and sedation procedures an individual child may need. The studies, however, must be tailored on an individual basis as the addition of the CT study can increase exposure to the child and should only be performed after appropriate justification and with adherence to optimized low dose pediatric protocols.

Molecular Imaging with PET-CT and PET-MRI in Pediatric Musculoskeletal Diseases.

Molecular imaging has emerged as an integral part of oncologic imaging. Given the physiologic changes that precede anatomic changes, molecular imaging can enable early detection of disease and monitoring of response. [18F] Fluorodeoxyglucose (FDG) Positron emission tomography (PET) is the predominant molecular imaging modality used in oncologic assessment and can be performed using PET/CT or PET/MR. In pediatric patients, PET/MRI imaging is generally preferred due to low radiation exposure and PET/MRI is particularly advantageous for imaging musculoskeletal (MSK) diseases, as MRI provides superior characterization of tissue changes as compared to CT. In this article, we provide an overview of the typical role of PET CT/MRI in assessment of some common pediatric malignancies and benign MSK diseases with case examples. We also discuss the relative advantages of PET/MRI compared to PET/CT, and review published data with a primary focus on the use of PET/MR.

Use of Neoadjuvant Vandetanib in Aggressive Pediatric Medullary Thyroid Carcinoma.

Novel use of vandetanib in a child with aggressive MTC with prolonged response to treatment.

Towards a More Inclusive Future: A Comprehensive Assessment of Gender Diversity in Nuclear Medicine Education, Training and Workforce.

The field of nuclear medicine has undergone remarkable advances, particularly with the introduction of new devices, radionuclides for imaging and therapy, new clinical applications, and emergence of medical evidence. As this dynamic field continues its rapid expansion, there is an urgent need to increase the number of well-trained professionals globally. Consequently, advocating for nuclear medicine as a thriving field of study and work for women becomes paramount in ensuring the establishment of a robust workforce capable of meeting the growing demands. True gender equality will only be achieved when there is equal representation across the spectrum of the nuclear medicine professions, including nuclear medicine technologists, radiopharmacists, radiochemist, medical physicists, nuclear medicine physicians, administrators, academics, and leaders. Currently, the workforce exhibits an imbalance, with females predominating among nuclear medicine technologists, while the number of female physicians, and those in leadership positions remains comparatively lower. There are various factors which contribute to the existing inequities. Societal expectations often impose traditional gender roles that somehow discourage women from pursuing a career in the science, technology, and mathematics (STEM) fields, including nuclear medicine. Additionally, prevailing unequal work conditions and gender biases within the workplace can create barriers that hinder women's professional growth and development. Ways of addressing inequalities includes ensuring female participation at all levels of education and training and promoting the field at undergraduate level in medical school. Mentorship programs have demonstrated great success in guiding and supporting women at various stages of their careers. Therefore, there is a need for their expansion and enhancement. Furthermore, female role models play a pivotal role in shattering gender stereotypes and inspiring other women to pursue careers in nuclear medicine and its related fields. By addressing the existing imbalances and fostering an environment that actively encourages and supports women, we can harness the full potential of all professionals, thus ensuring the ongoing progress and advancement of nuclear medicine.

The State-of-the-Art PET Tracers in Glioblastoma and High-grade Gliomas and Implications for Theranostics.

MR imaging is currently the main imaging modality used for the diagnosis and post therapeutic assessment of glioblastomas. Recently, several innovative PET radioactive tracers have been investigated for the evaluation of glioblastomas (GBM). These radiotracers target several biochemical and pathophysiological processes seen in tumors. These include glucose metabolism, DNA synthesis and cell proliferation, amino acid transport, cell membrane biosynthesis, specific membrane antigens such as prostatic specific membrane antigens, fibroblast activation protein inhibitor, translocator protein and hypoxia sensing agents, and antibodies targeting specific cell receptor antigen. This review aims to discuss the clinical value of these PET radiopharmaceuticals in the evaluation and treatment of GBMs.