In brachytherapy, why is it important to use two orthogonal films?

Using two orthogonal films in brachytherapy is essential for the accurate three-dimensional (3D) reconstruction of source positions. In brachytherapy, radioactive sources are placed directly within or near the tumor, and understanding their position relative to surrounding tissues is critical for effective treatment planning and delivery.

When two orthogonal films are utilized, they can provide images from two different perspectives, allowing for a clearer understanding of the spatial orientation of the sources. This dual perspective helps medical dosimetrists better visualize and localize the radioactive sources, facilitating precise treatment planning. Accurate 3D reconstruction is vital to ensure that the radiation dose is delivered to the target volume while minimizing exposure to healthy surrounding tissues. This balance is crucial in maximizing treatment effectiveness and reducing side effects.

Without the use of two orthogonal films, the accuracy of source localization could be compromised, potentially affecting the overall success of the brachytherapy treatment. Thus, the use of two orthogonal films is a standard practice in this field to enhance precision and safety in treatment delivery.