Why geometric accuracy is important in radiation therapy?

Geometric accuracy in radiation therapy is crucial for several reasons:

1. Precise Targeting: The goal of radiation therapy is to deliver high doses of radiation to the cancerous cells while minimizing dose to healthy tissues. Achieving geometric accuracy ensures that the radiation beam is delivered precisely to the intended target, reducing the potential for damage to surrounding healthy structures.

2. Treatment Plan Optimization: Radiation therapy plans are designed based on precise patient data and imaging. Any deviations from the planned geometry can affect dose distribution and compromise the effectiveness of the treatment. Accurate geometric setup ensures that the treatment is delivered as planned and that the dose is optimized to maximize tumor coverage and sparing of healthy tissues.

3. Patient Safety: Geometric accuracy is essential for protecting the patient from unintended radiation exposure. Deviations from the planned geometry can result in overdosing or underdosing of the target area or unnecessary irradiation of healthy tissues. Accurate positioning and alignment of the patient during treatment ensure that the radiation dose is delivered safely and precisely to the desired location.

4. Quality Assurance: Maintaining geometric accuracy is part of a rigorous quality assurance program in radiation therapy. Regular checks and calibrations of treatment machines, imaging systems, and patient positioning devices are performed to ensure that the delivered treatment matches the planned geometry. Geometric accuracy is vital for ensuring the overall quality and safety of the radiation therapy process.

5. Reproducibility: Geometric accuracy allows for consistent and reproducible treatments over multiple fractions or sessions. This consistency is especially important in techniques like stereotactic radiosurgery (SRS) or stereotactic body radiotherapy (SBRT), where high precision is required to deliver the prescribed dose accurately and effectively to the target.