Periosteal reaction, also known as periosteal hyperplasia, is an increase in bone growth caused by stimulation of the periosteum and increased activity of osteoblasts in the inner layer of the periosteum, which usually indicates the presence of a lesion. Histologically, an increase in osteoblasts in the inner layer of the periosteum is seen, by new bone trabeculae. The periosteal reaction is not specific and is commonly seen in inflammation, tumors, trauma, subperiosteal hemorrhage, etc. It is also seen in normal growth and developmental stages. Examination items: CT examination of bone, joint and soft tissue CT examination of bone, joint and soft tissue is a method of examining bone, joint and soft tissue by CT. It mainly focuses on injuries and diseases of bones, joints and soft tissues. It is suitable for patients with bone, joint and soft tissue diseases. Examination role CT examination of bone, joint and soft tissue can understand the lesions of bone, joint and soft tissue, and has diagnostic significance for bone, joint and soft tissue diseases. 2.Before the examination: fasting Indicator interpretation results Normal: Specific analysis according to the specific situation. No specific normal range. Abnormal: Abnormal results: 1. bone and joint and soft tissue masses. 2. bone and joint tumors. 3. bone and joint injuries. People who need to be examined: If there is pain in the limb in line with the location of the swelling (or lump), low back pain, unexplained limb pain, swelling in the soft tissue of the limbs, localized lumps, pain and other symptoms, please undergo CT examination of bone joints and soft tissues. Examination procedure 1. Intravenous injection of drugs: Different imaging agents are used according to different purposes of examination. After injection, please rest quietly, do not talk to others and avoid tense body position. The waiting time after injection is different for different examination items (basically more than 40 minutes). 2.Empty urine before PET/CT examination (for tumor screening) to avoid urine contamination of body surface and clothes. 3.During the PET/CT examination of the body, both arms need to be raised, and the examination time is usually about 20 minutes; the brain examination does not require both arms to be raised, and the examination time is usually about 10 minutes. Usually, family members are not allowed to enter the scanning room during the scanning process. 4. When the examination is completed, the doctor on duty will observe whether the image quality meets the requirements and notify the patient to leave after approval; depending on the condition, some patients may need delayed imaging or CT-enhanced scanning, and an informed consent form must be signed before CT-enhanced examination.