Lorenzo Biassoni

The new EANM paediatric dosage card

IntroductionIn a recent publication, Jacobs et al. proposed the use of three tracer-dependent dosage cards for paediatric nuclear medicine.Materials and methodsBased upon this work, the EANM dosimetry and paediatrics committees introduce a condensed and revised version of this dosage card for major nuclear medicine paediatric diagnostic procedures, replacing the previous card by Piepsz et al. and including a set of minimum activities.ResultsThe activities to be administered result in weight-independent effective doses to the children. In addition, the introduction of minimum activities guarantees a minimum standard of image quality throughout Europe and avoids a variety of administered activities in children of the same weight in different countries, which was the case when using the previous EANM dosage card.

The presence of vesicoureteric reflux does not identify a population at risk for renal scarring following a first urinary tract infection

Background: Childhood urinary tract infection (UTI) with or without vesicoureteric reflux (VUR) may predispose to renal scarring. There is no clear consensus in the literature regarding imaging following UTI in infancy. Aims: To define the role of cystography following a first UTI in children aged under 1 year, when urinary tract ultrasonography (US) is normal. Methods: Retrospective data collection of 108 children (216 renal units) aged under 1 year at the time of a bacteriologically proven UTI. All had a normal US and underwent both catheter cystogram and DMSA test. Sensitivity, specificity, likelihood ratios positive and negative, and diagnostic odds ratio were calculated for VUR on cystography versus scarring on DMSA. Results: VUR was shown in 25 (11.6%) renal units. Scarring on DMSA was seen in 8 (3.7 %) kidneys. Only 16% of kidneys with VUR had associated scarring; 50% of scarred kidneys were not associated with VUR. The likelihood ratio positive was 4.95 (95% CI 2.22 to 11.05) and the likelihood ratio negative was 0.56 (95% CI 0.28 to 1.11). The diagnostic odds ratio was 8.9, suggesting that cystography provided little additional information. Conclusion: Since only 16% of children with VUR had an abnormal kidney, the presence of VUR does not identify a susceptible population with an abnormal kidney on DMSA. In the context of a normal ultrasound examination, cystography contributes little to the management of children under the age of 1 year with a UTI. In this context, a normal DMSA study reinforces the redundancy of cystography.

Guidelines for 18F-FDG PET and PET-CT imaging in paediatric oncology

ObjectiveThe purpose of these guidelines is to offer to the nuclear medicine team a framework that could prove helpful in daily practice. These guidelines contain information related to the indications, acquisition, processing and interpretation of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in paediatric oncology. The Oncology Committee of the European Association of Nuclear Medicine (EANM) has published excellent procedure guidelines on tumour imaging with 18F-FDG PET (Bombardieri et al., Eur J Nucl Med Mol Imaging 30:BP115–24, 2003 [2]. These guidelines, published by the EANM Paediatric Committee, do not intend to compete with the existing guidelines, but rather aim at providing additional information on issues particularly relevant to PET imaging of children with cancer.ConclusionThe guidelines summarize the views of the Paediatric Committee of the European Association of Nuclear Medicine. They should be taken in the context of “good practice” of nuclear medicine and of any national rules, which may apply to nuclear medicine examinations. The recommendations of these guidelines cannot be applied to all patients in all practice settings. The guidelines should not be deemed inclusive of all proper procedures or exclusive of other procedures reasonably directed to obtaining the same results.

Phase II Study of Temozolomide in Relapsed or Refractory High-Risk Neuroblastoma: A Joint Société Française des Cancers de l’Enfant and United Kingdom Children Cancer Study Group–New Agents Group Study

PURPOSE To determine the response rate (RR) of neuroblastoma (NB) in children to temozolomide (TMZ), and evaluate the duration of response and tolerance of the drug in this patient population. PATIENTS AND METHODS A multicenter, phase II evaluation of an oral, daily schedule of TMZ (200 mg/m2/d x 5 days every 28 days) was undertaken in children with refractory or relapsed high-risk NB (metastatic or localized with Myc-N amplification). Response assessment was based on imaging with two-dimentional measurement of disease and meta-iodobenzylguanidine (MIBG) score. Activity was defined by a reduction in lesion size or isotope uptake at anytime. Methodology included a two-step design using Flemings method with a first step of 15 patients and a second of 10 additional patients if two to four responses had been observed in the first cohort. All data was centrally reviewed by a panel. RESULTS Twenty-five assessable patients were recruited over a 14-month period in 14 centers and received 94 cycles of chemotherapy. Twenty-three patients had metastatic NB either refractory (n = 9) or in relapse (n = 14). Grade 3 or 4 thrombocytopenia was the most frequent toxicity (16% of cycles). Myelosuppression resulted in treatment delays and dose reductions (24% and 21% of cycles, respectively). Response (complete response, very good partial response, or partial response) was observed in five patients (RR = 20% +/- 8%) with a median duration of 6 months and an objective or mixed response in five additional patients. CONCLUSION Temozolomide shows activity in heavily pretreated patients with NB, and deserves further evaluation in combination with another drug.

Guidelines for lung scintigraphy in children

The purpose of this set of guidelines is to help the nuclear medicine practitioner perform a good quality lung isotope scan. The indications for the test are summarised. The different radiopharmaceuticals used for the ventilation and the perfusion studies, the technique for their administration, the dosimetry, the acquisition of the images, the processing and the display of the images are discussed in detail. The issue of whether a perfusion-only lung scan is sufficient or whether a full ventilation–perfusion study is necessary is also addressed. The document contains a comprehensive list of references and some web site addresses which may be of further assistance.

Dual energy x-ray absorptiometry and quantitative ultrasound are not interchangeable in diagnosing abnormal bones

Objective To evaluate whether dual energy x-ray absorptiometry (DXA) and quantitative ultrasound (QUS) classify the same children as ‘abnormal’ (SD (z) score (SDS) ≤−2). Methods Speed of sound (SOS) was measured at the radius and tibia using QUS and lumbar spine bone mineral density (BMD) using DXA in 621 subjects aged 5–20 years; healthy 412, cystic fibrosis 117 and obese 92. Results BMD SDS positively (p<0.001) and tibia SOS SDS negatively correlated with size (p<0.05). Disagreement between DXA and QUS for ‘abnormal’ scans occurred in 6–31%. Those with abnormal BMD and normal SOS SDS had lower mean BMI SDS than those with normal BMD and abnormal SOS SDS. SOS measurements were unobtainable in some children, especially in the obese group. Conclusions DXA and QUS identify different individuals as ‘abnormal’. Agreement between BMD and tibia SOS is lower in obese subjects. Without a gold-standard, it is difficult to determine which technique is more ‘correct’.

Guidelines for the use of PET-CT in children

Division of Imaging, Kings College, PET Centre at St Thomas’ Hospital, Guys’ and St Thomas’ Foundation NHS Trust, London, Great Ormond Street Hospital for Sick Children, City and Royal Victoria Hospitals Belfast, Leeds Teaching Hospitals NHS Trust, Blackpool Victoria Hospital, University College London Hospitals NHS Trust and Aberdeen Royal Infirmary, UK Correspondence to Dr Sally F. Barrington, MBBS, MSc, FRCP, MD, Division of Imaging, Kings College, PET Centre at St Thomas’ Hospital and Guys’ and St Thomas’ Foundation NHS Trust, London, UK E-mail: sally.barrington@kcl.ac.uk

Pre- and postcaptopril renal scintigraphy as a screening test for renovascular hypertension in children

We studied the ability of pre- and postcaptopril renal scintigraphy to predict renovascular disease (RVD) in children. Retrospective review of medical notes and radiology reports of all hypertensive children who had had both pre- and postcaptopril renal scintigraphy with [99mTc] dimercaptosuccinic acid (DMSA) and/or [99mTc] mercaptoacetyltriglycine (MAG3) and digital subtraction angiography (DSA). 81 children aged 1–18 (median 10) years were studied with 62% (51) having a diagnosis of RVD. Main renal artery disease, intrarenal disease, and both main and intrarenal artery disease were present in 25, 14, and 12 patients respectively. The isotope study accurately diagnosed RVD, confirmed by DSA, in 47% (24 of 51) children, with eight false positive studies. The sensitivity, specificity, and positive and negative predictive values of the isotope study to predict RVD were 48%, 73%, 76%, and 51%, respectively. Pre- and postcaptopril renal scintigraphy was unable to predict RVD in children.

Airway Deposition of Nebulized Gene Delivery Nanocomplexes Monitored by Radioimaging Agents

Receptor-targeted nanocomplexes are nonviral vectors developed for gene delivery to the airway epithelium for the treatment of pulmonary disease associated with cystic fibrosis. The present study aimed to optimize the delivery of the nanocomplex by nebulization, and to monitor the in vivo deposition of radiolabeled vector in the airways of a large animal model by γ-camera scintigraphy. Large White weaner pigs were nebulized with nanocomplexes mixed with technetium-99m radiopharmaceuticals. The aerosol deposition scans suggested that the nebulized radiovectors were deposited mainly in the trachea-main bronchi and in the midregion of the lungs. The plasmid biodistribution, assessed by real-time PCR, correlated with the scintigraphy images. The highest plasmid copy numbers were found in the bronchial areas and in the tissues proximal to the main bronchi bifurcation. Immunohistochemistry detected transgene expression in the tracheal and bronchial ciliated epithelium. Histological analysis of lung tissue showed no evidence of inflammation, and no increase in inflammatory cytokines or inflammatory cells was detected in the bronchoalveolar lavage. The deposition of nebulized nanocomplexes coassociated with technetium-99m can be monitored by nuclear medicine techniques. The use of a noninvasive strategy to follow the delivery of the vector could improve the clinical management of patients undergoing cystic fibrosis gene therapy.

Technetium-99m-pertechnetate scintigraphy in children with symptomatic Meckel's diverticulum.

First, we are puzzled by the study population. The authors state that the study was prospective in nature, but they do not mention the inclusion and exclusion criteria at entry – that is, before the Tc-99m-pertechnetate scan was performed [1]. Their patients were those with a final definitive or suspected diagnosis of Meckel’s diverticulum; however, they do not say on what basis this diagnosis was made (whether on pathology after surgery or on other criteria). They also excluded 27 children with intestinal duplication and incidental Meckel’s diverticulectomy (n= 11), but do not give reasons for this. The patients appear to have been selected after the Tc-99mpertechnetate scintigraphy was performed and the diagnosis made (cf. first two lines of page 1163), which would skew the study findings. Therefore, it remains unclear from their description whether this was a truly prospective study or was in fact a retrospective review following surgical confirmation. Their study population includes a significant proportion of acute cases [32/73 (44%) patients presented with complications]: this is not the typical patient population referred for a Tc-99mpertechnetate scan.