Comparison of inverse-planned three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for non-small-cell lung cancer

Journal Article · Thu Mar 01 04:00:00 EST 2007 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2006.09.047· OSTI ID:20944723

Christian, Judith A ^[1]; Bedford, James L ^[1]; Webb, Steve ^[1]; Brada, Michael ^[1]

---

1. Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton (United Kingdom)

Purpose: Lungs are the major dose-limiting organ during radiotherapy (RT) for non-small-cell lung cancer owing to the development of pneumonitis. This study compared intensity-modulated RT (IMRT) with three-dimensional conformal RT (3D-CRT) in reducing the dose to the lungs. Methods: Ten patients with localized non-small-cell lung cancer underwent computed tomography (CT). The planning target volume (PTV) was defined and the organs at risk were outlined. An inverse-planning program, AutoPlan, was used to design the beam angle-optimized six-field noncoplanar 3D-CRT plans. Each 3D-CRT plan was compared with a series of five IMRT plans per patient. The IMRT plans were created using a commercial algorithm and consisted of a series of three, five, seven, and nine equidistant coplanar field arrangements and one six-field noncoplanar plan. The planning objectives were to minimize the lung dose while maintaining the dose to the PTV. The percentage of lung volume receiving >20 Gy (V{sub 20}) and the percentage of the PTV covered by the 90% isodose (PTV{sub 90}) were the primary endpoints. The PTV{sub 90}/V{sub 20} ratio was used as the parameter accounting for both the reduction in lung volume treated and the PTV coverage. Results: All IMRT plans, except for the three-field coplanar plans, improved the PTV{sub 90}/V{sub 20} ratio significantly compared with the optimized 3D-CRT plan. Nine coplanar IMRT beams were significantly better than five or seven coplanar IMRT beams, with an improved PTV{sub 90}/V{sub 20} ratio. Conclusion: The results of our study have shown that IMRT can reduce the dose to the lungs compared with 3D-CRT by improving the conformity of the plan.

• OSTI ID: 20944723
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 67; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ALGORITHMS
BEAMS
CARCINOMAS
COMPUTERIZED TOMOGRAPHY
LUNGS
PATIENTS
PLANNING
PNEUMONITIS
RADIATION DOSES
RADIOTHERAPY