Volumetric modulated arc therapy: Planning and evaluation for prostate cancer cases Journal Article
| Authors: | Zhang, P.; Happersett, L.; Hunt, M.; Jackson, A.; Zelefsky, M.; Mageras, G. |
| Article Title: | Volumetric modulated arc therapy: Planning and evaluation for prostate cancer cases |
| Abstract: | Purpose: To develop an optimization method using volumetric modulated arc therapy (VMAT) and evaluate VMAT plans relative to the standard intensity-modulated radiotherapy (IMRT) approach in prostate cancer. Methods and Materials: A single gantry rotation was modeled using 177 equispaced beams. Multileaf collimator apertures and dose rates were optimized with respect to gantry angle subject to dose-volume-based objectives. Our VMAT implementation used conjugate gradient descent to optimize dose rate, and stochastic sampling to find optimal multileaf collimator leaf positions. A treatment planning study of 11 prostate cancer patients with a prescription dose of 86.4 Gy was performed to compare VMAT with a standard five-field IMRT approach. Plan evaluation statistics included the percentage of planning target volume (PTV) receiving 95% of prescribed dose (V95), dose to 95% of PTV (D95), mean PTV dose, tumor control probability, and dosimetric endpoints of normal organs, whereas monitor unit (MU) and delivery time were used to assess delivery efficiency. Results: Patient-averaged PTV V95, D95, mean dose, and tumor control probability in VMAT plans were 96%, 82.6 Gy, 88.5 Gy, and 0.920, respectively, vs. 97%, 84.0 Gy, 88.9 Gy, and 0.929 in IMRT plans. All critical structure dose requirements were met. The VMAT plans presented better rectal wall sparing, with a reduction of 1.5% in normal tissue complication probability. An advantage of VMAT plans was that the average number of MUs (290 MU) was less than for IMRT plans (642 MU). Conclusion: The VMAT technique can reduce beam on time by up to 55% while maintaining dosimetric quality comparable to that of the standard IMRT approach. © 2010 Elsevier Inc. All rights reserved. |
| Keywords: | clinical article; retrospective studies; intensity modulated radiation therapy; treatment planning; cancer radiotherapy; radiation dose; radiotherapy dosage; calibration; retrospective study; algorithms; prostate cancer; prostatic neoplasms; prescription; prostate; intensity-modulated radiotherapy; physical therapy; tumors; radiotherapy, intensity-modulated; dosimetry; probability; radiation injuries; intermethod comparison; collimator; radiotherapy planning, computer-assisted; critical structures; cancer control; stochastic model; health care planning; prostate cancers; standards; rectum; dosimeters; optimization; volumetric modulated arc therapy; cavity resonators; tumor control probability; normal tissue complication probabilities; mean dose; dose rate; dose-volume; average numbers; conjugate gradient descents; delivery time; gantry angles; leaf position; monitor units; multileaf collimators; on time; optimal multileaf collimator; optimization method; plan evaluation; planning target volumes; prostate treatment; rectal wall; stochastic sampling; conjugate gradient method; bladder wall; femur head; rotation |
| Journal Title: | International Journal of Radiation Oncology, Biology, Physics |
| Volume: | 76 |
| Issue: | 5 |
| ISSN: | 0360-3016 |
| Publisher: | Elsevier Inc. |
| Date Published: | 2010-04-01 |
| Start Page: | 1456 |
| End Page: | 1462 |
| Language: | English |
| DOI: | 10.1016/j.ijrobp.2009.03.033 |
| PUBMED: | 19540062 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 12" - "Export Date: 20 April 2011" - "CODEN: IOBPD" - "Source: Scopus" |
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