Radiotherapy Dosimetric Treatment Verification using Electronic Portal Imaging Device (EPID)

Background: Ensuring the accurate delivery of prescribed radiation doses in radiotherapy is of paramount importance, as errors in dose delivery can cause serious harm to healthy tissues. Therefore, to ensure the prescribed dose is delivered, measurements or dose determinations are conducted on a phantom or the patient's body before or during treatment. Materials and Methods: In vivo dosimetry can help identify various systematic and random errors, such as errors in treatment plan implementation, linear accelerator output errors, patient anatomical changes, and patient setup errors. This type of dosimetry serves as a patient-specific quality assurance (PSQA) method. The use of in vivo dosimetry is recommended by the World Health Organization to prevent injuries and increase the accuracy of the prescribed dose. Many modern commercial dosimetry tools employ two-dimensional dosimeters based on diodes or ionization chambers for in vivo dosimetry. These tools are subject to inherent limitations including: - A limited number of measurement points in a two-dimensional space (plane). - Challenges with the hardware setup of dosimetry systems. Results: Alongside these dosimetry methods, there is potential in utilizing the existing capabilities of Electronic Portal Imaging Devices (EPID) for in vivo dosimetry purposes. EPIDS do not require installation or setup similar to the aforementioned dosimetry systems as they are already mounted on the linear accelerator. Consequently, they do not need additional setup and can be used for quality control before and during treatment. Conclusion: The digital images from EPID systems have high spatial resolution and are obtained in real-time. Therefore, EPID has the potential to lead to more effective quality assurance in patient treatment.

کلیدواژه ها:

EPID ، Dosimetry ، Radiotherapy