Study of effect of lung tumor location and volume on dosimetric parameters using Alderson Rando phantom

Abstract

Objective To study the effect of the location and volume of tumors on the normal lung dose-volume parameters for lung cancer. Methods An sphere with a diameter of 2 cm made of tissue-equiv-alent material used for simulating tumor was inserted into the superior lobe, middle lobe, inferior lobe of the right lung, and superior lobe, inferior lobe of the left lung of the Rando phantom, respectively. 5-field sIM-RT plans were designed. The prescribed dose was 60 Gy/2 Gy/30 f, and 99% of the planning target volume received this dose. Dose-volume parameters of normal lung tissue including V5, V10, V20, V30, V50 and mean lung dose were analyzed and compared. Results For the dose-volume parameters, the diameter and the po-sition of the tumor have a significant effect (P < 0.05). With the diameter expanding from 2 cm to 3 cm,the parameters associated with tumor in various lobes increased by a range between 3.83%-125.38%,while the parameters linked with tumor in different lobes increased by a range between 10.46%-51.46% with the diameter expanding from 3 cm to 4 cm. Conclusions Location and diameter of sphere-like tumor have obvious effect on dose-volume parameters. Knowing about the degree of influence will help oncologists and physicists to evaluate treatment planning better and reduce radiation pneumonitis. Key words: Phantom; Lung neoplasms/location and volume; Lung tissue/dosimetric