PURPOSE: To investigate set-up errors, suggest the adequate planning target volume (PTV) margin and image-guided radiotherapy frequency in head and neck (H&N) cancer treated with intensity-modulated radiotherapy (IMRT) assessed by kV cone-beam computed tomography (CBCT). METHODS: We analyzed 360 CBCTs in 60 patients with H&N cancer treated with IMRT. The target delineation was contoured according to ICRU62. PTVs were generated by adding a 3–5 mm margin in all directions to the respective clinical target volumes. The kV CBCT images were obtained at first three days of irradiation and weekly thereafter. The overall mean displacement, range, systematic (∑) and random (σ) errors were calculated. Adequate PTV margins were calculated according to the van Herk formula (2.5∑ + 0.7r). RESULTS: The mean of set-up errors was less than 2 mm in any direction. The overall frequency of set-up displacements greater than 3 mm was 3.9% in medial-lateral (ML) direction, 8% in superior-inferior (SI) direction, and 15.5% in anterior-posterior (AP) direction. The range of translations shifts was 0–9 mm in ML direction, 0–5 mm in SI direction and 0–10 mm in AP direction, respectively. After systematic set-up errors correction, the adequate margin to overcome the problem of set-up errors was found to be less than 3 mm. CONCLUSION: Image-guided kV CBCT was effective for the evaluation of set-up accuracy in H&N cancer. The kV CBCT at first three fractions and followed-by weekly appears adequate for reducing significantly set-up errors in H&N cancer treated with IMRT technique. Finally, 3–5 mm PTV margins appear adequate and safe to overcome the problem of set-up errors.
Cone-Beam Computed Tomography ; Drug Therapy ; Head and Neck Neoplasms ; Head ; Humans ; Neck ; Radiotherapy ; Radiotherapy, Image-Guided ; Radiotherapy, Intensity-Modulated ; Translations

We reported a successful case management of G3 skin acute dermatitis in a 32-year-old woman affected by locally advanced breast cancer underwent adjuvant chest wall irradiation. Skin acute toxicity with dry desquamation areas was treated daily with dressing medication using physiological solution, oxygen therapy and applying hyaluronic acid gauze. At the end of radiotherapy treatment, G3 skin acute dermatitis with moist desquamation was observed, so the patient continued advanced wound dressing shifted to twice weekly with physiological solution, oxygen therapy and applying hydrocolloid dressing. The patient completed radiotherapy treatment without interruption and one month after treatment acute skin toxicity was resolved with pain relief. We suggest that advanced dressing with trained nursing staff is essential in this sub-set of patients due to guaranteed continuation of radiotherapy treatment, indispensable to ensure patient cure.

We reported a successful case management of G3 skin acute dermatitis in a 32-year-old woman affected by locally advanced breast cancer underwent adjuvant chest wall irradiation. Skin acute toxicity with dry desquamation areas was treated daily with dressing medication using physiological solution, oxygen therapy and applying hyaluronic acid gauze. At the end of radiotherapy treatment, G3 skin acute dermatitis with moist desquamation was observed, so the patient continued advanced wound dressing shifted to twice weekly with physiological solution, oxygen therapy and applying hydrocolloid dressing. The patient completed radiotherapy treatment without interruption and one month after treatment acute skin toxicity was resolved with pain relief. We suggest that advanced dressing with trained nursing staff is essential in this sub-set of patients due to guaranteed continuation of radiotherapy treatment, indispensable to ensure patient cure.