adrenal medulla imaging

The meta-iodobenzamide is a type of adrenal neurogenic blocker that selectively acts on adrenergic neuron receptors, while the adrenal medulla is rich in adrenergic receptors. Therefore, the iodibenzyl bromide labeled with 131I or 123I can be ingested by the adrenal medulla after being introduced into the body to diagnose adrenal diseases such as pheochromocytoma. Basic Information Specialist Category: Oncology Inspection Category: Radionuclide Applicable gender: whether men and women apply fasting: fasting Tips: Severe cardiopulmonary dysfunction should be used with caution. Normal value normal. Clinical significance Adrenal medullary imaging is suitable for: 1. Location diagnosis of pheochromocytoma. 2. Determine the location and extent of metastatic foci of malignant pheochromocytoma. 3. Detection of residual lesions or recurrent lesions after pheochromocytoma surgery. 4. Auxiliary diagnosis of adrenal medulla hyperplasia. 5. CT or ultrasound imaging has suspicious adrenal lesions, and further provide the nature and functional status of the lesion. 6. Malignant pheochromocytoma. Precautions 1. A small number of pheochromocytoma can be not developed due to the lack of imaging agents, resulting in false negative results. 2. Patients taking certain drugs or tumors that affect the adrenal medulla intake may also affect the positive rate of imaging. 3. When abnormal concentrations of the adrenal gland occur, attention should be paid to the exclusion of false positive results from cardiac, liver, spleen, and intestinal radioactivity. 4. The catharsis should be taken 1 day before the imaging, and the bladder should be drained before imaging. Inspection process I. Imaging agent 1, 131I-MIBG: adult dose of 37 ~ 74MBq (1 ~ 2mCi), children reduce. 2. 123I-MIBG: Adult dose 185-370 MBq (5-10 mCi) or 370 MBq (10 mCi) / 1.7 m2 body surface area. 2. Imaging method 1, slow intravenous injection of 131I-MIBG, injection time should be > 30s, because MIBG is norepinephrine analog, after injection into the body may accelerate the discharge of norepinephrine in the granules, thus Causes high blood pressure. Therefore, the patient should be closely observed when injecting the imaging agent. The speed should not be too fast. If there is any discomfort, the injection should be suspended or stopped. 2, 24 and 48 hours after injection of the imaging agent (72h if necessary) after the gamma camera or SPECT line posterior and anterior imaging, the scope of imaging should include the head, chest, abdomen and pelvis area to facilitate the display of ectopic In medullary tumors, patients with anterior sputum emptied the bladder. Add oblique, lateral and full body imaging if necessary. 3, 131I-MIBG application of high-energy parallel hole collimator, energy peak 364keV, window width 20%, matrix 64 × 64 or 128 × 128, each frame of image acquisition 50 ~ 100k count or 300s. Patients with suspected ectopic pheochromocytoma are eligible for anterior and posterior whole body imaging. 4. At the end of the last imaging, if there is difficulty in locating the lesion, a small-dose kidney imaging agent (such as 99mTc-DMSA or DTPA) may be used for renal imaging, or multiple windows may be used for dual-nuclear collection. 5, after intravenous injection of imaging agents at 24h and 48h, respectively, anterior and posterior adrenal plane imaging, the application of low-energy universal parallel hole collimator, energy peak 159keV, window width 20%, each projection acquisition time 24h is 10min For 15 minutes at 48h, for patients with suspected ectopic pheochromocytoma, malignant pheochromocytoma metastasis or neuroblastoma, anterior and posterior whole body imaging from the skull to the knee should be performed according to the situation. Tomographic imaging: 24h after injection of imaging agent, single or dual probe SPECT, low energy high resolution collimator, matrix 64×64, probe rotation 360°, acquisition of 64 frames, 20s/frame, and pass Semi-quantitative analysis of adrenal (or pheochromocytoma)/background ratio was performed. Not suitable for the crowd Pregnant, lactating women. Adverse reactions and risks A small number of people may have transient facial flushing, sore back, chest tightness, palpitations and other reactions.