Pediatric nuclear medicine, Part I: Developmental cues

OBJECTIVE: Children provide a continuous challenge for the nuclear medicine technologist. The task of successfully completing a nuclear medicine procedure varies little among a 20-y-old, a 40-y-old and a 60-y-old patient. Successful completion of a procedure varies much more among a 2-y-old, a 4-y-old and a 6-y-old. Successfully completing a pediatric nuclear medicine procedure includes quick acquisitions, technically acceptable images or calculations, and satisfied patients and parents. Understanding your patient is crucial, and it provides the parents with a greater sense of comfort and confidence about the nuclear medicine technologist and the procedure. After reading this article the nuclear medicine technologist should be able to: (a) discuss the developmental stages of children according to several major theories; (b) identify the physical and mental expectations for each age group; (c) explain applications for incorporating this information into common pediatric nuclear medicine practice; and (d) discuss the common realities surrounding the behavior of children and their parents. A second article will feature tips, indications and populations for common pediatric procedures.     

Pediatric gastrointestinal nuclear medicine

General localization of gastrointestinal bleeding through the use of labeled red blood cells may be performed in children, or (99m)Tc-pertechnetate may be used if a Meckel's diverticulum is suspected. As in adults, cholecystitis and biliary leak may be assessed in children via (99m)Tc-IDA derivatives. Gastroesophageal reflux can be evaluated by oral consumption of the child's usual diet labeled with (99m)Tc sulfur colloid. For the scintigraphic determination of pulmonary aspiration, a relatively high concentration of tracer within a drop of liquid is placed beneath the child's tongue followed by dynamic imaging of the respiratory tract. Colonic transit scintigraphy can aid in the identification and therapeutic decision-making in patients with functional fecal retention, the most common cause of chronic constipation in children. (18)F-DOPA positron emission tomography is useful for classifying pancreatic involvement in infantile hyperinsulinism as focal or diffuse, thereby differentiating between patients who should receive curative focal pancreatic resection versus those who should receive medical management. Assessment of protein-losing enteropathy can be conducted scintigraphically and, compared with fecal alpha-1 antitrypsin collection, the scintigraphic method can detect esophageal and gastric protein loss. Also, scintigraphic quantification of protein loss can be performed without the requirement for fecal collection. Intestinal inflammation in children with inflammatory bowel disease can be evaluated using (99m)Tc white blood cells. The scintigraphic method is safe, accurate, well-tolerated by children and complementary to endoscopy in most patients.     

Pediatric musculoskeletal nuclear medicine

This article reviews the current role of nuclear medicine in common benign and malignant pediatric musculoskeletal conditions and discusses future applications.     

Costing nuclear medicine diagnostic procedures

To the Editor: Referring to a recent special report about the cost analysis of twenty-nine nuclear medicine procedures, I would like to clarify some basic aspects for determining costs of nuclear medicine procedure with various costing methodologies. Activity Based Costing (ABC) method, is a new approach in imaging services costing that can provide the most accurate cost data, but is difficult to perform in nuclear medicine diagnostic procedures. That is because ABC requires determining and analyzing all direct and indirect costs of each procedure, according all its activities. Traditional costing methods, like those for estimating incomes and expenses per procedure or fixed and variable costs per procedure, which are widely used in break-even point analysis and the method of ratio-of-costs-to-charges per procedure may be easily performed in nuclear medicine departments, to evaluate the variability and differences between costs and reimbursement - charges.     

Pediatric applications of renal nuclear medicine

This review should be regarded as an opinion based on personal experience, clinical and experimental studies, and many discussions with colleagues. It covers the main radionuclide procedures for nephro-urological diseases in children. Glomerular filtration rate can be accurately determined using simplified 2- or 1-blood sample plasma clearance methods. Minor controversies related to the technical aspects of these methods concern principally some correction factors, the quality control, and the normal values in children. However, the main problem is the reluctance of the clinician to apply these methods, despite the accuracy and precision that are higher than with the traditional chemical methods. Interesting indications are early detection of renal impairment, hyperfiltration status, and monitoring of nephrotoxic drugs. Cortical scintigraphy is accepted as a highly sensitive technique for the detection of regional lesions. It accurately reflects the histological changes, and the interobserver reproducibility in reporting is high. Potential technical pitfalls should be recognized, such as the normal variants and the difficulty in differentiating acute lesions from permanent ones or acquired lesions from congenital ones. Although dimercaptosuccinic acid scintigraphy seems to play a minor role in the traditional approach to urinary tract infection, recent studies suggest that this examination might influence the treatment of the acute phase, the indication for chemoprophylaxis and micturating cystography, and the duration of follow-up. New technical developments have been applied recently to the renogram: tracers more appropriate to the young child, early injection of furosemide, late postmicturition and gravity-assisted images and, finally, more objective parameters of renal drainage. Pitfalls mainly are related to the interpretation of drainage on images and curves. Dilated uropathies represent the main indication of the renogram, but the impact of this technique on the management of the child is, in a great number of cases, still a matter of intense controversy. Direct and indirect radionuclide cystography are interesting alternatives to the radiograph technique and should be integrated into the process of diagnosis and follow-up of vesicoureteral reflux.     

Cost analysis of twenty-nine nuclear medicine procedures

The aim of this study was to compare actual cost estimates for diagnostic procedures as applied in the nuclear medicine department of our University Hospital, with cost estimates obtained through an analytical activity-based costing methodology. Activity data on the use of twenty-nine nuclear medicine procedures were collected. The actual hospital prices for the fiscal years of 2003-2004 were obtained from the Accounting Department of the Hospital. Cost estimates were calculated per patient. Activity-based data were compared with hospital prices and also with unit costs from the activity-based costing methodology. Our results showed a significant statistical difference between unit cost estimates per patient based on hospital prices, as compared with those based on unit costs. This study shows that in our university hospital, reliance on generic hospital prices for nuclear medicine procedures, considerable underestimates their real cost by a mean value of 40% as derived through the activity-based costing methodology and can lead to substantial financial hospital deficits.     

Carcinogenic risk in diagnostic nuclear medicine: biological and epidemiological considerations

During the last decade new data have become available on the mechanism of carcinogenesis and on cancer induction by ionizing radiation. This review concentrates on these two items in relation to the use of radiopharmaceuticals in diagnostic nuclear medicine. On the basis of reports of expert committees, the concept of radiation risk is elucidated for high and low doses. Mortality risk factors due to ionizing radiation are put in perspective to other risks. The extra risk for patients who undergo a scintigraphic examination for fatal cancer is very small and is of the order of 1.4×10^–4. It is most unlikely that this figure can even be verified by actual measurement since the majority of nuclear medicine patients will die of other causes before the radiogenic cancer manifests itself.     

Infrequently performed studies in nuclear medicine: Part 1

Nuclear medicine is a diverse field with a large number of different studies spanning virtually all organ systems and medical specialties. Many nuclear medicine procedures are performed routinely; others may be performed only rarely, sometimes less than once per year. The infrequent nature of many studies makes it challenging to retain relevant knowledge and skills. This 2-part article provides a review of several infrequently performed studies. The topics discussed in Part 1 include dacroscintigraphy, LeVeen shunts, scintimammography, right-to-left shunts, left-to-right shunts, and heat-damaged red blood cells. After reading this article, the reader should be able to list and describe the indications for each study, list the doses and describe their proper method of administration, and describe problems that may arise during the imaging procedure and how they should be handled.     

Cost-effectiveness of nuclear medicine procedures in renovascular hypertension

The role of nuclear medicine in the differential diagnosis of renovascular hypertension (RVH) has been a highly controversial one. The reason for this rests with the lack of specificity of this test in screening for RVH. Although renography is very sensitive in detecting unilateral renal disease, it is nonspecific and an unacceptable number of false-positives occur. Recently the introduction of captopril renography has provided a new stimulus for reevaluation of this test in the differential diagnosis of renovascular disease. In spite of prevailing opinion, a careful review of the relative cost of renography and digital subtraction angiography (DSA) demonstrates that there is a role for renography in this differential diagnosis at all stages of investigation. Routine renography, when interposed between DSA studies, significantly reduces the cost per case of RVH found. If captopril renography proves as specific as is theoretically possible, the cost reductions achieved can be even greater. There is a significant and cost-efficient role for renography in the differential diagnosis of RVH. In addition to its reduction of cost in case finding, renography also avoids the risk of contrast media administration in a significant number of patients by reducing the population for screening to those at very high risk of disease.     

Preparing children for day case nuclear medicine procedures

OBJECTIVES: To audit standards developed for children undergoing nuclear medicine procedures involving day case attendance on the renal unit. METHODS: A prospective audit was undertaken of 210 children (113 males) undergoing day case nuclear medicine procedures in a teaching hospital department catering for adult and paediatric patients. An audit sheet was completed by both ward and nuclear medicine staff at the time of the procedure over an 18-month period. RESULTS: The majority of families were given relevant information about the procedures and adequate notice before the scan date. Most patients were offered surface analgesia for the venepuncture and play preparation before the procedure. Fifty-eight per cent of patients were successfully cannulated at the first attempt and 88% after three attempts. Only 4% of children were sedated. The median delay between the scheduled and actual scan time was 15 min, with 71% of children being scanned within the standard of a 0-20-min delay. Most delays were due to logistic problems within the department (43%). Cannulation problems (35%) and patient-related factors (22%) accounted for further delays. CONCLUSIONS: The audit of these locally agreed standards has resulted in changes in practice, including nurse training for cannulation and better scheduling within the nuclear medicine department. We believe that play preparation is an essential component for all potentially painful procedures, with few patients requiring sedation. The standards could be used for comparative audits between units.