Positron emission tomography (PET) is a well-established diagnostic imaging technique used in oncology, infection imaging, neurology, and cardiology in adults. The technique is used less often in children, but recent advances have improved the imaging quality and shortened the length of the imaging procedure (1), making pediatric PET scanning increasingly relevant. Single-photon emission computed tomography (SPECT) has been used for more than 2 decades in pediatric patients, and different protocols and regimes have been presented (2,3).

Nuclear medical and PET examinations in children are very rewarding, especially when the staff understand the requirements of the child and parent. A successful examination can be defined as one in which a high-quality study is achieved and the child and parents feel that their emotional needs are met (4).

“Children are very special persons who need to be treated with caution and care and whose integrity must be
respected” (5). In nuclear medicine, dealing with children is very different from dealing with adults. Children are not just small adults. They differ in their psychology, normal physiology, and pathophysiology, and various special issues need to be considered when planning a PET or a SPECT scan for a child. Everybody involved must enjoy working with children, and the scans should be performed by a child-oriented staff. Patience, flexibility, imagination, and truthfulness are crucial qualities when dealing with children.

Children have parents, and the parents are just as worried as the children, often even more so. In each case, the parents’ anxiety affects the child and hence the entire examination, but the parents also are able to offer the child the best comfort and security. This is why dealing with children also means dealing with the parents, and this is done successfully through communication and understanding and by figuring out how best to use their potential as contributors to the imaging process.

An important principle in diagnostic imaging in general is to limit the use of radiation, especially in children and in those with chronic diseases (see Chapter 9). The tracer most frequently used for clinical studies is fluorodeoxyglucose (FDG) (Fig. 66.1). The injected activity is 3 MBq per kilogram of body weight for brain studies (effective dose equivalent ≈ 4 mSv) and 6 MBq per kilogram of body weight for whole-body scans (effective dose equivalent ≈ 6 mSv.). The dose to the brain is 0.24 ± 0.05. The target organ (the organ receiving the highest radiation dose), the bladder wall, receives 1.03 ± 2.10 MBq. This can be reduced by good hydration and rapid drainage of radioactive urine. The heart wall is estimated to receive 0.89 ± 0.26 MBq. These figures are from a study that demonstrated that FDG-PET studies in newborns resulted in radiation doses lower than in adults and lower than infants who underwent conventional scintigraphy with technetium 99m (^99mTc)-DTPA or ^99mTc-MDP (6).

The amount of activity administered to an adult can be reduced for children by one of the following methods: body weight/70 kg, body surface area/1.73 m², or height/174 cm (7). The pediatric task group of the European Association of Nuclear Medicine (EANM) has published a dose schedule (8) (Table 66.1). Furthermore, the child should be well hydrated, since frequent micturition reduces the radiation to gonads.

Organization and good communication are important in the nuclear medicine and the PET departments, especially between the camera and laboratory staffs. Equally important is comprehensive contact with the pediatric departments. This is not easily done, because nuclear medicine examinations are only some of many different examinations for which pediatric patients are referred, and they are definitely among the most complicated to prepare for. It is beneficial to give lectures in the pediatric departments not only for the physicians but most importantly for the staff nurses and also to have a contact person in each department for every specific examination (9). This will generally be the nurse taking care of the child, as these complicated examinations necessitate special arrangements. The technologist who is to perform the examination has to make the arrangements with the pediatric department, and all communications concerning a specific examination should be written on the referral in case another technologist has to take over. Good cooperation with the team of anesthesiologists is essential, as it takes flexibility to assist a nuclear medicine and PET department in performing pediatric scans. It saves time if both staffs are familiar with one another’s procedures during the examination in order to minimize the time spent.

Information on planned examinations should be given both verbally and in writing. Good information will help to ensure compliance and keep the child’s anxiety at a minimum. The information leaflets for children should be specific for the different age groups, and pictures can be used for children who cannot read but are old enough to discuss the pictures.