Treatment fields in radiation therapy can be shaped using which of the following?

In radiation therapy, treatment fields can indeed be shaped using various methods to ensure that the radiation targets the tumor while sparing surrounding healthy tissue. Each of the mentioned shaping techniques has its specific applications and advantages.

Custom-made blocks are specifically designed to conform to the contours of the target area, allowing precise shaping of the radiation beam. These blocks are often used when the tumor's shape is irregular or when specific areas of normal tissue need to be protected.

Multi-leaf collimators (MLCs) are devices integrated into linear accelerators that can dynamically shape the treatment beam. They consist of many small, individual leaves that can move independently, allowing for real-time adjustments to the beam's shape during treatment. This flexibility is particularly beneficial for complex tumor geometries and enables highly conformal radiation therapy.

Standard blocks, although less frequently used in modern clinical practice compared to MLCs, are pre-fabricated blocks that can be placed in the path of the radiation beam. They can effectively block radiation from reaching certain areas, thus protecting healthy tissue.

Thermal aids refer to techniques that utilize thermal energy to mold or conform certain materials (such as certain plastics) to specific shapes. While thermal aids can play a role in preparing various materials for use in shaping treatment