Gamma Camera / Scintillation Camera

What is Gamma Camera?

A Gamma camera, also known as a scintillation camera, is a diagnostic and monitoring device that is crucial to the practice of nuclear medicine. Nuclear medicine is a medical specialty that uses Radiopharmaceuticals, which are radioactive medications, in the diagnosis and treatment of patients. A small amount of such medication is administered to patients and this produces a minute amount of radiation from the body that lasts for a limited time and can be picked up by the Gamma camera. The dose of the radiation is insignificant and does no harm to the individual.

The gamma camera is used to generate images from the ionizing radiation that is emitted from the body. The camera typically comprises of a flat and narrow table on which the patient must lie down.

Gamma cameras usually have between one to three camera heads that is used to record the images. There is a flat surface on each camera head, which has to be positioned as close as possible to the patient. Supports for the camera heads typically come in the form of a gantry or sturdy metal arms. The procedure is safe and neither the dose of the drug with the radiation nor the camera cause any kind of discomfort. There have never been any complications associated with the procedure.

What is a Gamma Camera used for?

Gamma cameras are extremely important for radiologists as they enable them to perform what are medically called "Scintigraphy scans" that reveal detailed information about the functioning of various organs such as lungs, heart, thyroid, parathyroids, liver, kidneys and adrenals to name a few. This makes them extremely useful in medical care as they are used in the diagnosis of health conditions and also to monitor follow up treatment. They can also pick up spread of cancers to bones or organs and these appear as hot spots.

The scans so obtained help experts to diagnose and identify various cancers, congenital abnormalities and numerous other conditions, allowing them to plan an effective course of action. Corrective action to modify and change treatment plans is also possible as specialists are able to gauge patient responsiveness to ongoing treatments.

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How does a Gamma Camera Work?

To begin with, a tracer or radiopharmaceutical is administered to the patient orally, intravenously or through inhalation. The patient’s body contains radioactive tracer for a brief period, during which gamma cameras can be used to generate images. These cameras image the radiation from the tracer, with Technetium-99m being the most commonly used tracer. It has a relatively long half-life of six hours and can be incorporated into a variety of molecules making it capable of targeting different systems of the body. As the tracer travels through the human body, it emits radiation that can be picked up and tracked by a crystal in the camera that sparks or scintillates (flashes) in response to exposure to gamma rays. The crystal in the camera is positioned in front of an array of light sensors so that the flashes of light upon exposure get converted into an electrical signal. This is why the camera is also known as a scintillating camera. This technology helps to gauge functioning and health of various body structures and organs as experts can recognize conditions based on the accumulation or exclusion of tracer from certain areas.

What sets the gamma camera apart from other imaging devices is that it examines the functioning of various bodily processes, not just the anatomy or structure.

Gamma cameras may have been of little use prior to the advent of the information age, but today with computer technology, advanced calculations can be computed very rapidly, converting the Radiation detection by the camera into cohesive information that greatly helps Radiologists. The spread of the radioisotope through the patient’s body can in fact be tracked in real time as the images are created in a fraction of a second. This means that doctors don’t just get static images of an organ or structure but they can view highly detailed images showing the process, like contraction of the heart. This type of imaging is called Dynamic Imaging. The Gamma camera, can in fact be used for different types of diagnoses and monitoring by simply changing the radiopharmaceutical that is administered to the patient. For example, to produce images of the skeletal structure, instead of the heart or kidneys, the patient will be given an intravenous dose of radioactive solution that adheres to the bony structure instead.

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Who Operates a Gamma Camera?

Gamma cameras are operated and handled by a number of medical and technical specialists with expertise in radiology or nuclear medicine. Many specialists have training in both nuclear medicine and cardiology or oncology and there are also experts who specialize primarily in Radiology. While various specialists who are involved in the treatment and diagnosis of the patient will determine the necessity of gamma camera testing and monitoring, the actual operation of the machine is carried out by nuclear medicine technologists. Nuclear medicine technologists are health care experts who have earned a university degree in Nuclear medicine.

This qualifies them to use and measure radiopharmaceuticals and give injections and draw blood samples. This means that they are the specialists who also administer the tracer prior to operation of the gamma camera. They are not only authorized to use gamma cameras, but they also have expertise and skills to process and analyze the findings of tests and nuclear medicine studies. They also have an understanding of the various diseases and health conditions that are dealt with in Nuclear medicine.

What is the duration to complete a Nuclear Scan with Gamma Camera?

Scintigraphy with Technitium 99 usually takes 3-4 hours. There are two parts to it. In the first part a radio-isotope tracer is injected in the vein and in the second part the uptake is captured by the camera.

The total duration of the scan depends on the Radiopharmaceutical used. A Bone scan may take 1 to 4 hours.

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When is a Radio-isotope scan not advised?

If a woman is pregnant or breastfeeding, the isotope scan is not advised.

How is Safety Ensured while using a Gamma Camera?

Patients are exposed to some amount of radiation during such procedures, but the amount varies depending on the specific procedure, the organ or structure being examined and the physical dimensions of the patient. Either way, health care providers follow stringent safety practices and will only administer the lowest possible dosage that can provide high quality results, so as to minimize unnecessary exposure to the drug.