Treatments & Therapies

Kidney scintigraphy – treatment, effects & risks

Renal scintigraphy

Kidney scintigraphy is a proven nuclear medicine examination method. It is primarily used for the side-by-side evaluation of the function of the kidneys and also of the urinary organs of the urogenital tract. This is made possible by using a very well-tolerated radioactive substance that is injected into the patient: By recording its excretion via the kidneys with a gamma camera, the kidney function can be reliably checked without invasive intervention in the body.

What is renal scintigraphy?

The scintigraphy of the kidneys belongs to the field of nuclear medicine and is a meaningful diagnostic supplement to the classic examinations such as sonography ( ultrasound ) and special blood tests .

Kidney function is measured using a radioactive substance that is usually injected into the patient ‘s vein in small doses. Technetium, a chemical element, is the most common tracer used to monitor the uptake and excretion of fluid by the kidneys. Due to its natural radiation, it is possible with the gamma camera to convert the course of the liquid enriched with this substance in the area of ​​the kidneys and the urinary system into meaningful image material.

These images are called a scintigram. In addition, the performance of the kidneys is also expressed as a percentage using the appropriate software and compared with the specified standard values. In contrast to the laboratory analysis of the relevant blood values, the kidney scintigraphy can show the function of the two kidneys separately. To round off the diagnostics, the scintigraphy is often combined with an examination of the kidney values ​​in the blood .

Function, effect & goals

With the kidney scintigraphy, nuclear medicine has an effective tool if you want to examine the blood flow in the two kidneys, their functionality (kidney clearance) and, above all, their performance with regard to excretion, i.e. the outflow of urine into the bladder , separately.

Pathological processes such as tumors or inflammation in the area of ​​the renal pelvis and the ureters as well as urinary outflow disorders of various causes can be detected in this way using non-invasive diagnostics. Kidney scintigraphy is also suitable for showing possible consequences of high blood pressure , such as the relevant narrowing of renal arteries.

It is also used for special questions – for example with regard to the success of a kidney transplant or an operation in the field of urology as well as in small children with malformations in the area of ​​the urinary organs. In connection with chemotherapy or radiotherapy , the functional performance of the kidneys can be monitored with scintigraphy without an invasive procedure. All this enables the administration of a small amount of a radioactive and kidney-penetrating tracer, which is usually applied into the arm vein.

No special preparation is required for this examination. Only certain X-ray examinations should be avoided in the last two days before the nuclear medicine diagnostics, since the contrast medium used can falsify the validity of the scintigraphy. If damage caused by high pressure is to be diagnosed, blood pressure medication may also have to be discontinued after consultation with the doctor. However, it is important to drink enough before the examination – especially in the last 30 minutes beforehand.

In this way, a good accumulation of the tracer in the kidney tissue and sufficient excretion are achieved. The flow of urine can also be increased by administering water-repellent medication – so-called diuretics – shortly before the examination. The images are taken in the supine position.

The gamma camera records the physiological processes in the kidneys and urinary organs over a period of around 30 to 40 minutes. Due to the rapid excretion of the radioactive tracer, it is possible in this relatively short time to get a comprehensive picture with regard to the individual question of the kidney scintigraphy performed. Not infrequently, the high informative value of scintigraphy can already identify clinical pictures before they become apparent in laboratory diagnostics via changes in blood values.

Risks, side effects & dangers

Like all other nuclear medicine examination methods, renal scintigraphy causes fear in many patients because of the radioactive drug that is injected into the arm vein . However, this is unfounded, since the radiation exposure caused by the tracer is low and in the range of a classic X-ray examination, for example of the lungs .

In addition, the radioactivity leaves the body quickly through natural excretion via the kidneys or urinary tract. This process can be supported by drinking consistently after the examination. A relative contraindication – meaning that the benefits and urgency of the examination must be carefully weighed up by the doctor – only exists around pregnancy and breastfeeding. Doctors recommend that breastfeeding mothers express and discard breast milk for 48 hours because of the radionuclide administered.

In addition, patients should limit contact with pregnant women or small children to a minimum for about a day after a kidney scintigraphy – as after any nuclear medicine examination. An intolerance reaction to the injected tracer is also generally not to be expected.

Compared to the contrast agents used, for example, in the context of a CT ( computed tomography ), technetium can usually be used without hesitation in patients with a high allergy potential. The recording itself by the gamma camera is absolutely painless. There are no restrictions after the kidney scintigraphy, so that the patient can carry out his private or professional obligations as usual immediately after the examination.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.