Various radiopharmaceuticals are available for imaging pediatric patients in an acute care setting. This article focuses on the common applications used on a pediatric patient in acute care. To confirm the clinical diagnosis of brain death, brain scintigraphy is considered accurate and has been favorably compared with other methods of detecting the presence or absence of cerebral blood flow. Ventilation-perfusion lung scans are easy and safe to perform with less radiation exposure than computed tomography pulmonary angiography and remain an appropriate procedure to perform on children with suspected pulmonary embolism as a first imaging test in a hemodynamically stable patient with no history of lung disease and normal chest radiograph. 99mTc pertechnetate scintigraphy (Meckel's scan) is the best noninvasive procedure to establish the diagnosis of ectopic gastric mucosa in Meckel's diverticulum. Hepatobiliary scintigraphy is the most accurate diagnostic imaging modality for acute cholecystitis. 99mTc-dimercaptosuccinic acid scintigraphy is the simplest, and the most reliable and sensitive method for the early diagnosis of focal or diffuse functional cortical damage. Bone scintigraphy is a sensitive and noninvasive technique for the diagnosis of bone disorders such as osteomyelitis and fracture. Of recent, positron emission tomography imaging using 18F-NaF has been introduced as an alternative to bone scintigraphy. 18F-fluorodeoxyglucose-positron emission tomography has the potential to replace other imaging modalities, such as the evaluation of fever of unknown origin in pediatric patients, with better sensitivity and significantly less radiation exposure than gallium scan.