Dosimetric comparison of intensity-modulated radiation therapy for early-stage glottic cancers with and without the air cavity in the planning target volume

For early-stage glottic cancers, intensity-modulated radiation therapy (IMRT) has been shown to have comparable local control to 3D-conformal radiotherapy with the advantage of decreased dose to the carotid arteries. The planning target volume (PTV) for early glottic cancers typically includes the entire larynx, plus a 3 to 5 mm uniform margin. The air cavity within the larynx creates a challenge for the inverse optimization process as the software attempts to “build up” dose within the air. This unnecessary attempt at dose build-up in air can lead to hot spots within the rest of the PTV and surrounding soft tissue.
Source: Medical Dosimetry - Category: Radiology Authors: Source Type: research