What is a disadvantage of using a physical wedge?

Using a physical wedge in radiation therapy is advantageous for achieving certain dose distributions; however, it also has its drawbacks. One significant disadvantage of using a physical wedge is the hardening of the beam that occurs as it passes through the wedge material.

When radiation passes through a wedge, the material absorbs some of the lower energy photons more than higher energy ones. This process leads to beam hardening, which results in an increase in the average energy of the beam. Consequently, this change can affect the dose distribution within the patient's tissue and may alter the therapeutic efficacy of treatment plans. It is important for medical dosimetrists and radiation oncologists to consider this potential effect on the dose received by the target volume and surrounding tissues when planning treatments. Additionally, unlike advanced techniques such as dynamic wedges or IMRT (Intensity-Modulated Radiation Therapy), the use of physical wedges can lead to more complications in achieving optimal dose delivery due to this hardening phenomenon.