Whole brain radiotherapy using four-field box technique with tilting baseplate for parotid gland sparing
- Author:
Jaehyeon PARK
1
;
Ji Woon YEA
Author Information
- Publication Type:Original Article
- Keywords: Whole brain radiotherapy; Four-field box technique; Brain metastases; Parotid gland sparing
- MeSH: Brain; Head; Humans; Methods; Neoplasm Metastasis; Parotid Gland; Radiotherapy; Skull; Supine Position
- From:Radiation Oncology Journal 2019;37(1):22-29
- CountryRepublic of Korea
- Language:English
- Abstract: PURPOSE: The aim of this study is to evaluate the efficacy and feasibility of four-field box whole brain radiotherapy (FB-WBRT) with tilting baseplate by comparing bilateral WBRT (B-WBRT). METHODS AND MATERIALS: Between March 2016 and September 2018, 20 patients with brain metastases underwent WBRT using the four-field box technique. WBRT is performed with a dose of 30 Gy in 10 fractions daily. Two computed tomography simulations per person were performed. One was in the traditional supine position for B-WBRT and the other by applying the tilting acrylic supine baseplate to elevate the head by 40° for FB-WBRT. The B-WBRT used the field-in-field technique, which is the most commonly used method in our institution. The FB-WBRT comprised anterior, posterior, and bilateral beams. A wedge was applied in anterior and posterior fields to compensate for skull convexity. RESULTS: The average of Dmean of both parotid glands was 10.2 Gy (range, 3.8 to 17.8 Gy) in B-WBRT and 5.4 Gy (range, 2.0 to 11.7 Gy) in FB-WBRT (p < 0.05). Compared to B-WBRT, FB-WBRT reduced the mean dose of the right and left parotid glands from 10.1 Gy to 4.9 Gy and from 10.4 Gy to 5.8 Gy, respectively (p < 0.05). Further, V₅, V₁₀, V₁₅, V₂₀ for the parotid gland decreased significantly in FB-WBRT (p < 0.05). The Dmax and Dmean of lens decreased according to the dose-volume histogram. CONCLUSION: Compared to B-WBRT, FB-WBRT with a tilting baseplate is a simple and effective method that takes feature of noncoplanar beam to protect the parotid gland.
