Cone-beam computed tomography dose monitoring during intensity-modulated radiotherapy in head and neck cancer: parotid glands

Clin Transl Oncol. 2013 May;15(5):412-5. doi: 10.1007/s12094-012-0946-4. Epub 2012 Oct 13.

Abstract

Purpose: To evaluate the dosimetric changes of parotid glands (PG) during a course of intensity-modulated radiotherapy (IMRT) in head and neck (H&N) cancer patients.

Methods: Ten patients with H&N cancer treated by IMRT were analyzed. The original treatment plan (CT(plan)) was transferred to cone-beam computed tomography (CBCT) acquired at the 15th and 20th treatment day (CBCT(plan) I and II, respectively). The PG mean dose (D(mean)), the dose to 50 % of the volume, and the percent of volume receiving 30 and 50 Gy were measured by the dose volume histogram.

Results: 30 IMRT plans were evaluated (3 plans/patient). All dosimetric end points increased significantly for both PG only when CT(plan) was compared to CBCT(plan) I. The D(mean) increased significantly only for ipsilateral PG (p = 0.02) at week 3.

Conclusion: During a course of IMRT, CBCT is a feasible method to check the PG dosimetric variations. Perhaps, the 3rd week of radiotherapy could be considered as the time-check-point.

MeSH terms

  • Cone-Beam Computed Tomography*
  • Head and Neck Neoplasms / diagnostic imaging
  • Head and Neck Neoplasms / radiotherapy*
  • Humans
  • Parotid Gland / radiation effects*
  • Radiotherapy Dosage
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy, Intensity-Modulated*