**Core Concept**
Stereotactic radiosurgery (SRS) is a non-invasive, precise form of radiation therapy used to treat various intracranial lesions, including tumors, arteriovenous malformations, and functional disorders such as trigeminal neuralgia. It involves delivering a high dose of radiation to a specific target area with minimal exposure to surrounding healthy tissues.

**Why the Correct Answer is Right**
SRS employs advanced technology, including linear accelerators, to deliver radiation beams from multiple angles, allowing for precise targeting and minimization of radiation exposure to surrounding tissues. This technique is particularly useful for treating small, well-defined lesions that are difficult to access surgically. The high dose of radiation delivered in a single fraction is thought to induce DNA damage and cell death in the targeted cells.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is often incorrect because SRS does not typically involve the use of chemotherapy agents, which are systemic medications that target rapidly dividing cells. While chemotherapy may be used in conjunction with radiation therapy, it is not a component of SRS.

**Option B:** This option is incorrect because SRS often involves the use of gamma knife technology, which is a specific type of linear accelerator that delivers radiation beams from multiple angles to a precise target area.

**Option C:** This option is incorrect because SRS is not a form of external beam radiation therapy, which involves directing radiation beams from outside the body to a specific area.

**Clinical Pearl / High-Yield Fact**
One key consideration in SRS is the concept of the "radiobiological effective dose" (BED), which takes into account the total dose of radiation delivered, the number of fractions, and the overall treatment time to predict the likelihood of tumor control and side effects.

**Correct Answer:**
.