Whole-body scintigraphy or whole-body research (PCI) is an image exam requested by your doctor to investigate tumor location, disease progression, and metastasis. For this, radioactive substances, called radiopharmaceuticals, are used, such as iodine-131, octreotide or gallium-67, depending on the purpose of the scintigraphy, which are administered and absorbed by the organs, emitting radiation that is detected by the equipment. Know what radioactive iodine is for.
The images are obtained through a device, which tracks the entire body, after a day or two of the administration of the substance. Thus, it is possible to verify how the radiopharmaceutical is distributed in the body. The test result is said to be normal when the substance is distributed evenly in the body, and is indicative of disease when a large concentration of radiopharmaceutical is perceived in an organ or region of the body.
When full body scintigraphy is done
The whole body scintigraphy aims to investigate the primary site of a tumor, the evolution and whether or not there is metastasis. The radiopharmaceutical used depends on which system or organ you want to evaluate:
- PCI with iodine-131: its main objective is the thyroid, mainly in those who have already performed thyroid removal; Gallium-67 PCI: it is usually done to check the evolution of lymphomas, search for metastasis and investigate infections; PCI with octreotide: it is made to evaluate tumor processes of neuroendocrine origin, such as thyroid, pancreatic and pheochromocytoma tumors. See how to identify and treat pheochromocytoma.
The whole body scintigraphy is done under medical guidance and does not pose a risk to the patient, since the administered radioactive substances are naturally eliminated from the body.
How PCI is done
The full-body search is basically done in four steps:
- Preparation of the radioactive substance in the dose to be administered; Administration of the dose to the patient, either orally or directly into the vein; Image acquisition, through the reading made by the equipment; Image processing.
Full-body scintigraphy does not normally require the patient to fast, but there are some recommendations to be followed depending on the substance to be administered.
In the case of iodine-131, it is recommended to avoid foods rich in iodine, such as fish and milk, in addition to suspending the use of some medications, such as vitamin supplements and thyroid hormones before performing the test. If a full body scan is not done, but only a thyroid scan, you should fast for at least 2 hours. See how thyroid scintigraphy is done and what foods are rich in iodine that should be avoided for the exam.
The examination is done with the patient lying on his stomach and lasts about 30 to 40 minutes. In iodine-131 and gallium-67 PCI, images are taken 48 hours after the radiopharmaceutical administration, but if an infection is suspected, gallium-67 PCI should be performed between 4 and 6 hours after the substance is administered. In the PCI with octreotide, the images are taken twice, once with about 6 hours and once with 24 hours of substance administration.
After the examination, the person can return to normal activities and should drink plenty of water to help eliminate the radioactive substance faster.
Care before the exam
Before being subjected to full body scintigraphy, it is important that the person tells the doctor if they have any type of allergy, if they are using any medication that contains Bismuth, such as Peptulan, for example, which is used for gastritis, or if you are pregnant or breastfeeding, as this type of examination is not recommended, as it may affect the baby.
Side effects related to the administration of radiopharmaceuticals are rare, not least because very low doses are used, but allergic reactions, skin rash or swelling can occur in the region where the substance was administered. So it is important that the doctor knows the patient's condition.
