Dosimetric Comparison Between Intensity-Modulated with Coplanar Field and 3D Conformal Radiotherapy with Noncoplanar Field for Postocular Invasion Tumor

Journal Article · Thu Jul 01 00:00:00 EDT 2010 · Medical Dosimetry

DOI:https://doi.org/10.1016/j.meddos.2009.04.002· OSTI ID:21333980

Wenyong, Tu ^[1]; Jun, Zeng ^[2]; Weidong, Yin ^[3]; Yun, Li ^[2]

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1. Nuclear Medicine Technology Institution, School of Clinical Medicine, Southeast University, Nanjing (China)
2. Radiotherapy Department, YI-REN Hospital, Wuxi, Jiangsu Province (China)
3. Radiatherapy Department, Nanjing Second Hospital, Nanjing (China)

This study presents a dosimetric optimization effort aiming to compare noncoplanar field (NCF) on 3 dimensions conformal radiotherapy (3D-CRT) and coplanar field (CF) on intensity-modulated radiotherapy (IMRT) planning for postocular invasion tumor. We performed a planning study on the computed tomography data of 8 consecutive patients with localized postocular invasion tumor. Four fields NCF 3D-CRT in the transverse plane with gantry angles of 0-10 deg., 30-45 deg., 240-270 deg., and 310-335 deg. degrees were isocentered at the center of gravity of the target volume. The geometry of the beams was determined by beam's eye view. The same constraints were prepared with between CF IMRT optimization and NCF 3D-CRT treatment. The maximum point doses (D max) for the different optic pathway structures (OPS) with NCF 3D-CRT treatment should differ in no more than 3% from those with the NCF IMRT plan. Dose-volume histograms (DVHs) were obtained for all targets and organ at risk (OAR) with both treatment techniques. Plans with NCF 3D-CRT and CF IMRT constraints on target dose in homogeneity were computed, as well as the conformity index (CI) and homogeneity index (HI) in the target volume. The PTV coverage was optimal with both NCF 3D-CRT and CF IMRT plans in the 8 tumor sites. No difference was noted between the two techniques for the average D{sub max} and D{sub min} dose. NCF 3D-CRT and CF IMRT will yield similar results on CI. However, HI was a significant difference between NCF 3D-CRT and CF IMRT plan (p < 0.001). Physical endpoints for target showed the mean target dose to be low in the CF IMRT plan, caused by a large target dose in homogeneity (p < 0.001). The impact of NCF 3D-CRT versus CF IMRT set-up is very slight. NCF3D-CRT is one of the treatment options for postocular invasion tumor. However, constraints for OARs are needed.

• OSTI ID: 21333980
• Journal Information: Medical Dosimetry, Vol. 35, Issue 2; Other Information: DOI: 10.1016/j.meddos.2009.04.002; PII: S0958-3947(09)00028-4; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0958-3947
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
COMPUTERIZED TOMOGRAPHY
NEOPLASMS
OPTIMIZATION
PLANNING
RADIATION DOSES
RADIOTHERAPY
THREE-DIMENSIONAL CALCULATIONS