Coronary artery disease is a common disease in the world. Different methods such as exercise testing, electrocardiogram, single-photon diffusion tomography (SPECT), and cardiac angiography are used to diagnose CAD [1, 2]. Myocardial perfusion imaging (MPI) is widely used as a non-invasive clinical imaging technique for the diagnosis of coronary artery disease [3, 4, 5]. MPI in nuclear medicine consists of two steps: first is rest and the other is stress. Stress stage is done in two ways (drug stress or exercise).
In this phase, blood flow should increase. If the tide is reduced or limited, the vessels will be involved. The results are usually compared to the rest phase . Two most commonly used radiopharmaceuticals in heart scans are Tc-99m sestamibi and Tc-99m tetrofosmin. For sestamibi, tetrofosmin, and thallium, uptake in the myocardium is proportional to blood flow. Both tetrofosmin and sestamibi are excited from the body through the hepatobiliary system into the intestine [7,8,9,10]. The heart is enclosed among the diaphragm and the intestine and the liver, and it is located on the diaphragm above the left edge of the liver and near the intestine. For this reason, the liver, bile duct, and intestine cause excessive radiation. Therefore, radioactivity in the sub-diaphragm region can change the results in heart scan studies and make it harder for nuclear medicine studies to achieve the desired goal. Due to the proximity of the liver and the intestine to the bottom of the heart, proper judgment can be severe in CAD cases [11, 12].
The emergence of unusual cardiac activity is predictable in the imaging of myocardial perfusion, so to provide high-quality images for comment, it is essential to remove the liver-bile duct and digestive tract [3, 7, 13].
Some foods and fluids have been used to reduce or eliminate this problem, which they increase radiopharmaceutical hepatobiliary and intestine transition, including drinking milk, eating high-fat foods, drinking milk and water, injections of cholecystokinin, and administration of metoclopramide in myocardial perfusion SPECT. Fatty foods release cholecystokinin (CCK) and increase secretion bile and evacuate the gallbladder whereby increased clearance hepatobiliary and reduced infracardiac activity [1, 11, 14, 15]. The main route of excretion of technetium, the liver, and the secondary route is the gastrointestinal tract. Increasing age leads to a decrease in the performance of these two systems. Increasing age leads to a decrease in the ability of the liver system to purify the material. Digestive motions of the gastrointestinal tract become ineffective as they age. As a result, increased intake of fatty acids leads to gastrointestinal complications in the elderly. On the other hand, a decrease in the function of these systems results in a decrease in the clearance of radioactive substances from the body of the elderly. In a study by Hofman et al., the group received the milk compared to the group that received the water, radiation was significantly reduced, but it did not improve the interpretation of the images [16,17,18]. The study by Boz et al. indicates that eating solid and liquid foods before the resting stage reduced intestinal activity in Tc-99m tetrofosmin myocardial perfusion [19, 20]. Also, Purbhoo et al. showed that diluted lemon juice and milk reduced significantly infracardiac radiation in myocardial perfusion scan with radiopharmaceuticals Tc-99m sestamibi, which this reduction in the milk group had been more prominent . The purpose of our studies was to determine what steps should be taken before resting the SPECT myocardium so that we can reduce the side effects of the liver, intestine, and stomach interactions.