Gamma rays are a form of electromagnetic radiation used in cancer treatment due to their ability to penetrate tissues and deliver targeted energy. These high-energy photons originate from the decay of radioactive atomic nuclei. In medicine, they precisely target and destroy cancerous cells, minimizing impact on surrounding healthy tissues.
How Gamma Rays Affect Cancer Cells
Gamma rays are a type of ionizing radiation, meaning they remove electrons from atoms, creating charged particles. These high-energy photons interact with cellular components, notably the DNA within cancer cells. This interaction can directly damage the DNA structure, leading to breaks in its strands.
Beyond direct damage, gamma rays primarily cause indirect DNA damage by interacting with water molecules in cells. This interaction produces highly reactive molecules called free radicals, such as hydroxyl radicals. These free radicals damage DNA, preventing cancer cells from growing and dividing. Cancer cells, which typically divide rapidly, are more susceptible to this DNA damage than slower-dividing healthy cells, making gamma ray therapy a targeted approach.
Specific Treatment Approaches
Gamma Knife radiosurgery is a primary method for delivering gamma rays to treat certain cancers with high precision. Despite its name, Gamma Knife is not a surgical knife but a machine that uses concentrated radiation.
It employs numerous individual gamma ray beams, typically sourced from Cobalt-60. These low-intensity beams converge precisely at a single target point within the body, delivering a high dose of radiation to the tumor while minimizing exposure to surrounding healthy tissue.
This technique is primarily used for conditions within the brain and upper spine, including malignant and benign brain tumors, arteriovenous malformations (AVMs), and trigeminal neuralgia. While external beam radiation therapy (EBRT) also uses gamma rays, Gamma Knife offers enhanced precision for specific applications.
Delivering Treatment and Ensuring Safety
Treatment with gamma rays, especially via Gamma Knife radiosurgery, involves meticulous planning to ensure precision and patient safety. Before the procedure, detailed imaging, such as CT or MRI scans, is performed to locate the target area and create a 3D treatment plan. A specialized head frame or mask is often used to immobilize the patient’s head, ensuring beams are delivered to the exact location.
Many gamma ray procedures are non-invasive and often take place in an outpatient setting. A typical treatment session can last from a few minutes to several hours, depending on the target’s size, shape, and location. The goal is to maximize the radiation dose to the tumor while limiting exposure to nearby healthy tissues.
Patients generally experience few immediate side effects, which are usually temporary, including mild headaches, fatigue, or nausea. These effects are typically managed with medication, and most patients resume normal activities shortly after treatment.