In external beam radiation therapy, the most commonly used type of radiation is X-rays. This is primarily due to their ability to penetrate tissue effectively, making them ideal for targeting tumors while sparing surrounding healthy tissue. X-rays can be generated with linear accelerators, which allow for precise dosing and the ability to create various treatment plans that align with patient-specific anatomy and the location of the tumor.
Additionally, X-rays provide a therapeutic dose that can be finely tuned, allowing clinicians to deliver a focused beam to malignant cells while minimizing exposure to adjacent normal tissues. The versatility and effectiveness of X-rays make them the standard choice for many cancer treatments in external beam radiation therapy.
In contrast, alpha particles are primarily used in targeted alpha therapy and have limited penetration, making them unsuitable for external beam applications. Beta particles also have limited penetration and are typically used for different treatment modalities. Gamma rays, while used in some radiation therapies (such as certain types of brachytherapy), are less common in external beam radiation therapy compared to X-rays.