Bone and joint scanning is a nuclear study performed to assist in diagnosing pathological conditions as well as complications of bone disease. The advantage of bone scanning over other bone diagnostic procedures is that abnormalities, or "hot spots," appear 3 to 6 months before an x-ray reveals any pathology. Total body scanning is performed if metastatic disease to the bone is suspected. Total body scanning is important because all of the skeleton can reveal different locations of the metastases, such as the skull, long bones, pelvis, vertebrae, ribs, and sternum.²⁰

The study is performed after the IV administration of the radionuclide 99mTc as technetium Tc 99m hydroxyethylene diphosphonate (HEDP) or technetium Tc 99m methylene diphosphonate (MDP), with scanning, flow studies, and blood pool studies undertaken immediately or delayed to allow concentration of the radionuclide in the bones and joints. Concentration depends on bone metabolism, which determines the amount of uptake of the substance, and the blood flow, which increases the deposition of the material as the flow is increased. A decrease or absence of blood flow produces "cold" bone defects. It is the increase of radionuclide uptake and activity (chemisorption) on the scan that represents an abnormality because it becomes concentrated at a higher or lower rate than does normal bone tissue. There are, however, normal areas of increased activity in adults, such as the sternum and the sacroiliac, clavicular, and scapular joints. In children, normal areas of increased act-ivity are growth centers and cranial sutures.²¹ Gallium (67Ga) scanning after the administration of gallium citrate Ga 67 can follow a bone scan to obtain a more definitive study if acute inflammatory conditions such as osteomyelitis or septic arthritis are suspected (see later section titled "Gallium 67 Scanning").

• Normal uptake by chemisorption of radionuclide by the bone; no tumors, infection or inflammation, fracture, or joint derangement or joint inflammation

• Inability of client to remain still during the procedure, especially if the client is a child
• Multiple myeloma or thyroid malignancy causing false-negative scan for bone abnormalities

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Indications

• Determining the cause of unexplained bone or joint pain
• Diagnosing degenerative joint changes or septic arthritis that occurs in arthritic conditions revealed by increased uptake of radionuclide
• Confirming a diagnosis of temporomandibular joint derangement by SPECT studies
• Diagnosing primary malignant bone tumors such as osteogenic sarcoma, chondrosarcoma, and Ewing's sarcoma
• Determining metastatic malignant tumor from primary sites such as breast, lung, thyroid, pro-state, or kidney revealed by an increased uptake of radionuclide
• Diagnosing benign tumors or cysts revealed by minimal or normal uptake, with the exception of osteoid osteoma, which is revealed by increased uptake and blood pool activity
• Diagnosing osteomyelitis, usually in the femur, tibia, fibula, and humerus
• Determining acute osteomyelitis when performed with a 67Ga scan
• Detecting fractures (traumatic and stress) and evaluating healing after a fracture, especially when an underlying bone disease is present
• Diagnosing metabolic bone disease and differentiating among osteoporosis, osteomalacia, Paget's disease, and bone disorders secondary to hyperparathyroidism
• Detecting Legg-Calvé-Perthes disease and determining the phase of the disease in children, revealed by changes in uptake activity in each phase
• Evaluating prosthetic joints for infection, loosening, dislocation, or breakage revealed by increased uptake around the prosthesis
• Evaluating tumor response to radiation or chemotherapy
• Identifying appropriate site for bone biopsy

Contraindications

• Pregnancy, unless the benefits of performing the procedure greatly outweigh the risks to the fetus

[Section Outline]

• Indications
• Contraindications

Nursing Care Before the Procedure

Client teaching and physical preparation are the same as for any nuclear scan study (see section under "Brain Scanning").

• Inform the client of the scanning schedule, which begins 2 to 4 hours after the injection and then takes 1 hour to complete.
• A history should include assessment information about the musculoskeletal system and known and suspected bone diseases.
• If a full body scan it to be performed, request that the client remove all clothing and provide him or her with a hospital gown.

The client is placed on the examining table in a supine position with the site to be scanned exposed. To conduct a flow study, the radiopharmaceutical is injected IV, and images are obtained in sequence every 3 seconds for 1 minute. The client is reminded or assisted to remain very still during the procedure. A blood pool image is then obtained over the area. To improve tumor imaging by allowing the radionuclide to be taken up by the bones, a 2- to 3-hour delay takes place before static images are made. The client is requested to drink fluids during this time and is allowed to walk around or sit and read. Also, request that the client void before the delayed imaging to prevent interference with examination of the pelvic bones. After the delay, multiple images are obtained over the complete skeleton. A large-field-of-view camera is used to cover the entire area. Sacral lesions can be imaged by positioning the client on the hands and knees and using a tail on the detector.²² After 24 hours, additional views can be taken of a specific area, which can be useful in evaluating a fracture for repair processes. Total body imaging is performed primarily to determine metastatic sites that can be detected long before they are seen with x-ray radiography. If a SPECT study is performed for bone and joint imaging, the scanner is rotated around the client, with various views taken.

Nursing Care After the Procedure

Care and assessment after the procedure are the same as for any nuclear scan study (see section under "Brain Scanning").