Table of Contents
- What is Indocyanine Green (ICG)?
- How Does ICG Work?
- Medical Uses of ICG
- How is ICG Administered?
- Safety and Side Effects
- Ongoing Research and Future Applications
What is Indocyanine Green (ICG)?
Indocyanine Green, commonly abbreviated as ICG, is a medical dye used in various diagnostic and surgical procedures. It’s also known by other names such as IC-GREEN, SPY AGENT GREEN, or simply ICG[1][2]. This special dye is safe for use in the human body and has unique properties that make it valuable in medical settings.
How Does ICG Work?
ICG is what’s called a fluorescent dye. When injected into the body, it binds to proteins in the blood. When exposed to a special kind of light called near-infrared light, ICG glows or “fluoresces,” giving off a bright green color. This property allows doctors to visualize blood flow, lymphatic drainage, and other structures in the body that are normally difficult to see[3].
Medical Uses of ICG
ICG has a wide range of applications in medicine, including:
- Cancer Surgery: ICG helps surgeons identify and remove tumors more accurately. It’s used in various types of cancer surgeries, including:
- Bariatric Surgery: ICG is used to check blood flow in the stomach and intestines during weight loss surgeries[1]
- Lymphatic System Imaging: To visualize lymph nodes and lymphatic vessels, which is helpful in diagnosing and treating conditions like lymphedema (swelling due to blocked lymph drainage)[6]
- Liver Function Tests: ICG can be used to assess how well the liver is working
- Eye Angiography: To examine blood vessels in the eye
How is ICG Administered?
ICG is typically given in one of two ways:
- Intravenous (IV) Injection: The dye is injected into a vein, usually in the arm. This method is used when doctors need to see blood flow in larger areas of the body[1].
- Direct Injection: In some cases, ICG is injected directly into the area of interest. For example, in breast cancer surgery, it might be injected near the tumor site or under the skin[6].
After injection, special cameras or imaging devices are used to detect the fluorescence and create images that help guide the medical procedure.
Safety and Side Effects
ICG is generally considered very safe. It has been used in medical procedures for many years. However, like any medical treatment, there are some potential risks and side effects to be aware of:
- Allergic reactions: These are rare but can occur. Patients with a known allergy to iodine should inform their doctor, as ICG contains iodine[1].
- Mild side effects: Some patients may experience nausea, itching, or a headache after receiving ICG.
Your healthcare team will monitor you closely during and after the procedure to ensure your safety.
Ongoing Research and Future Applications
Researchers are continually finding new ways to use ICG in medicine. Some areas of ongoing research include:
- Improving surgical techniques for various types of cancer[7]
- Enhancing the accuracy of lymph node mapping in different cancers[8]
- Using ICG to guide nerve decompression surgeries[9]
- Exploring its use in rheumatoid arthritis to study lymphatic system changes[6]
As research continues, ICG may become even more widely used in various medical fields, potentially leading to improved diagnostic accuracy and surgical outcomes for patients.






