Certified Neuroscience Registered Nurse (CNRN) Practice Exam

What is a disadvantage of gamma-knife treatment for malignant brain tumors?

1. It cannot be used for large tumors

2. It's unable to detect malignant cells infiltrating normal tissues

3. It requires multiple sessions

4. It does not provide immediate symptom relief

The correct answer is: It's unable to detect malignant cells infiltrating normal tissues

Gamma Knife treatment, while a beneficial technique for targeting malignant brain tumors through precise radiation, has certain limitations. One notable disadvantage is its inability to detect malignant cells infiltrating normal tissues. This treatment primarily focuses on delivering a high dose of radiation to a specific lesion while sparing surrounding healthy tissue. While this is advantageous in targeting defined tumors, it does not have the capability to identify microscopic disease that has spread into neighboring healthy brain tissue. Consequently, if malignant cells infiltrate areas adjacent to the tumor, these cells may remain untreated, potentially leading to challenges in overall tumor management. Let’s consider the context of the other options: the assertion regarding large tumors is valid as Gamma Knife is generally more effective for smaller tumors due to the precision required in targeting. The requirement for multiple sessions is not necessarily true, as complex cases may only need a single session, and sometimes the treatment can be completed in one day depending on the tumor size and location. Immediate symptom relief is also not one of the characteristics of this treatment modality as Gamma Knife therapy focuses on long-term tumor control rather than immediate alleviation of symptoms.