What is skeletal scintigraphy?Skeletal scintigraphy or bone scintigraphy serves to detect active changes in the bones.
Skeletal scintigraphy, also known as bone scintigraphy, is an investigative method used to detect areas subject to increased bone metabolism. In diseases such as metastases of various malignant tumors, fractures (fractures), inflammatory changes and arthritis, there is an increased activity in the affected areas, which can be visualized by skeletal scintigraphy.
The investigation principle in skeletal scintigraphy is based on the fact that radioactively labeled phosphates attach to bone surfaces with increased metabolic activity. In this way, the entire skeletal system of the body can be represented with a low radiation exposure and the entire body can be examined for a pathologically increased bone remodeling.
This is an enormous advantage that skeletal scintigraphy has over X-ray examinations, in which only single sections of the skeleton are imaged.
Function, effect & goals
Skeletal scintigraphy is used for the detection or exclusion of tumors of the bone, metastases of the skeleton, unrecognized fractures as well as inflammation of bones or joints. Skeletal scintigraphy is also used in the case of suspected loosening of prostheses (hip or knee joint endoprosthesis), postoperative and post-traumatic complications, as well as unclear bone or joint pain.
Before the actual bone scintigraphy, it is necessary to give the patient a weak radioactive agent. This is usually done via a cannula in the arm vein. This agent first accumulates in the soft tissues after administration and then gradually attaches to the bone. The agent is absorbed differently depending on the type of tissue or change.
Depending on the task, the time also varies until skeletal scintigraphy allows optimal visualization. In most cases, after about two hours, the first shots and after another one to two hours, the late shots done. In the 2- or 3-phase skeletal scintigraphy, the images are taken directly after injection of the agent.
The patient should move as little as possible during skeletal scintigraphy. If necessary, breaks will be taken. A recording device, z. B. A gamma camera registers the radioactive rays, from which the image is then generated. Areas in which much contrast substance has been recorded are shown differently than areas with a lower accumulation. Often a two-dimensional image is sufficient, but it is also possible, after processing by computer, to produce a three-dimensional image or a series of layer images. An extension of skeletal scintigraphy is usually not necessary.
Since skeletal scintigraphy shows very accurate examination results, changes in the bones are indicated even if an X-ray examination does not yield any findings. For example, daughter tumors of the tumor in the skeleton occurring in cancer patients can be detected at an early stage. It is also possible to differentiate the location, type and intensity of the inflammatory lesions by means of bone scintigraphy in inflammation.
Risks, side effects & dangers
The radiation effect in skeletal scintigraphy is not increased compared to an X-ray examination or computed tomography. After a short time, the radioactive substance disintegrates and is excreted from the body with the urine.
The image itself does not generate radiation, only the rays produced by the agent are captured. Apart from the puncture injection, painless and radiation exposure is low, skeletal scintigraphy may also be useful in children. In pregnant women, however, it is only performed if there are no diagnostic alternatives.
Since the radioactivity of the contrast medium given in skeletal scintigraphy is low, no higher radiation exposure occurs. It roughly corresponds to the exposure to natural radioactivity within a year. The risk of radiation damage from skeletal scintigraphy is extremely low, but it can not be completely ruled out. Therefore, these examinations are not used as a routine examination, but only very specifically.
In rare cases infection, nerve damage or scarring may occur at the injection site for the radioactive substance. Also allergic reactions to the injected agent are possible in skeletal scintigraphy. These are rarely so severe that they cause serious complications.