General Aspects of Pediatric Nuclear Medicine

Abstract

Pediatric nuclear medicine is a very interesting, dynamic, and exciting field. Nuclear medicine contributes to the diagnosis of many diseases in children. Well-established procedures reveal physiological processes in vivo, permit early detection of disease, help patient management and therapeutic decisions, and provide an important tool to follow the success of therapy or to assess progression of disease. One of the reasons that nuclear medicine in pediatric patients remains successful is that nuclear medicine studies provide information about the patient’s condition that cannot be obtained easily (or sometimes at all) with other diagnostic methods. Some nuclear medicine procedures require pharmacologic interventions. Examples include the administration of furosemide, acetazolamide, phenobarbital, cholecystokinin analog, and dobutamine. Pediatric patients, with their wide range of body size, physical and psychological developmental changes, and medical disorders, present unique challenges. Patients in pediatric nuclear medicine range in weight from premature infants to young adults reaching adult weight. It has been said that children are not small adults, and even in nuclear medicine “one size does not fit all.”

Appendix 1: Example of a Patient/Parent Brochure About a Nuclear Medicine Procedure

Bone Scan in Nuclear Medicine

What is a bone scan? A bone scan is an image that shows bone blood flow, metabolism, and cell activity in the bones. There are two types of bone scans – planar and 3D (SPECT).

Why bone scans at this hospital? Our department of nuclear medicine is committed to providing a safe, comfortable, and child-friendly atmosphere with specialized:

• Nuclear medicine physicians with expertise in interpreting bone scans in children of all ages

• Technologists with experience imaging children

• Equipment adapted for pediatric use

• Protocols that keep radiation exposure as low as possible while assuring high image quality

When is a bone scan needed? A bone scan can detect very small changes in your child’s bones, even ones that may not be seen on regular X-rays. Bone scans can detect subtle injuries, stress changes, or small fractures that may result from intense playing or sports activity as well as infection or inflammation.

How should I prepare for a bone scan? There is no special preparation needed for this test. However, between the injection of the radiopharmaceutical and the scan, there is a 3–4-h waiting period. In addition, the scan time is approximately 30–60 min. Please schedule your day accordingly.

How is a bone scan obtained? Scans are obtained using special cameras called gamma cameras. Before the images are taken, a tiny volume of a radiotracer (radiopharmaceutical, ^99mTc-MDP) is injected in one of your child’s veins using a very small needle (smaller than the needles used for blood tests). Two-minute pictures showing blood flow to the bones may be obtained while the tracer is injected. The actual images of the bones are obtained approximately 3–4 h after the injection of the tracer.

After the injection, your child can continue with his or her normal activities while waiting for the scan to begin. When you return to nuclear medicine, the bone scan is obtained. Your child will lie on an imaging table, and the camera will slowly move around his or her body as several pictures are taken. The camera does not touch your child and does not produce radiation. It is very important that your child remains still during the imaging in order to obtain the best quality images. The number of images obtained and the total imaging time will vary depending on the diagnosis under consideration, although the average imaging time is about 1 h. Some of the images are three-dimensional (3D), and such images are also evaluated by “slicing” the image through different planes.

Bone scan in a young gymnast with back pain. His X-rays were normal, but you can see that on the bone SPECT, there is stress injury in the spine (arrows). The picture on the right upper quadrant is a volume-rendered image, while the others are slices of the 3D image. The slices help localize the lesion

What happens after the bone scan? Once the pictures are ready, the nuclear medicine physician will evaluate them and will produce and send a report to your child’s doctor. You will be free to leave and your child can resume normal activity.

What about radiation exposure? Your child will be exposed to a very small amount of radiation that is within the lower range of what is received from routine diagnostic imaging procedures that use X-rays. Nuclear medicine has been used on babies and children for more than 40 years with no known adverse effects from the low doses employed. We are committed to ensuring that your child receives the smallest radiation dose needed to obtain the desired result. Our doctors balance the medical benefits of any imaging test with potential radiation risks even if these are minuscule.

More information about nuclear medicine radiation safety can be found on the Image Gently website (www.imagegently.org).

This pamphlet is written to provide patients, parents, and caregivers with information about bone scans and radiation exposure. This information should not be used as a substitute for the advice from your doctor. If you are concerned or have any unanswered questions, you should talk with a nuclear medicine physician before the study begins.