What is the typical primary transmission percentage for a block used to shield a portion of the radiation field?

The typical primary transmission percentage for a block used to shield a portion of the radiation field generally falls between 3% to 5%. This value is important to understand, as it indicates the amount of radiation that can penetrate through the shielding material. In radiation therapy, blocks are used to selectively attenuate the radiation dose to areas that do not require treatment, effectively protecting healthy tissues while allowing the prescribed dose to reach the tumor or targeted area.

Blocks are designed to absorb or scatter radiation based on their material composition and thickness, contributing to this range of transmission percentage. A block with a well-designed density and thickness will effectively lower the transmission percentage, resulting in more efficient shielding. Therefore, the chosen percentage reflects a balance between sufficient attenuation of the radiation and practical limitations found in radio-protection practices.

Understanding this range is crucial for medical dosimetrists when planning treatments, as it plays a role in calculating the overall dose received by a patient and ensures the appropriate protection protocols are followed.