Dosimetric tests using the Step & Shoot technique for future implementation of IMRT with LINAC device at the ION

External radiotherapy is one of the most modern and safest techniques for the treatment of cancer patients. In Panama, the public entity in charge of the specialized treatment of this type of patients is the National Oncology Institute (ION). Currently, the ION performs treatments based on a technique called Three-Dimensional Conformal Radiotherapy (3D-CRT) with X-ray photon beams, allowing the radiation beam to be modified to treat the tumor and better protect the surrounding tissues. Unlike 3D-CRT, which generates fixed intensity in each radiation beam, Intensity Modulated Radiation Therapy (IMRT) modifies the intensity of each radiation beam. In the treatment of difficult cancers such as nasopharyngeal cancer, IMRT has demonstrated great advantages, protecting healthy anatomical structures while targeting and optimizing treatment to the volume of interest. Based on the above, the present research proposes to perform preliminary dosimetric tests on a Linear Accelerator (LINAC) from the ION to determine its capability to perform IMRT. Treatment planning was performed on simulated cases of nasopharyngeal cancer, using Monaco software. These planned treatments were physically executed with the LINAC irradiating the 3D phantom ArcCheck for In-Vivo dosimetry. The Step & Shoot IMRT technique was used at energies of 6 MV. The dosimetric results obtained were compared with the acceptance criteria established by the American Association of Medical Physicists (AAPM), showing early indications of the possible implementation of IMRT at ION.