Abstract
It is generally believed that the quality of intensity modulated radiation therapy (IMRT) treatment plans with finer multi-leaf collimator (MLC) leaf resolution is better. We tested this hypothesis by analyzing treatment plans optimized using Philips Pinnacle3 treatment planning system (TPS) for multiple patients with tumor sites located in Head and Neck (H&N), Prostate and Spine. For each patient, two IMRT plans are created using the same objective functions, optimization algorithm (Direct Machine Parameter Optimization), and other radiation therapy planning parameters: one with 0.5 cm leaf width and the other with 1.0 cm leaf width. The beam modeling of the two virtual machines in the TPS was exactly the same except for the MLC leaf width. The dose volume histogram (DVH) is used in the planning process. A criterion of 95% of the target volume receiving the prescribed dose was satisfied for all plans. Dose verification using a diode array (Mapcheck, Sun Nuclear) was also made to quantify the dosimetric accuracy of each plan in terms of average pass rate of total dose points using various evaluation criteria. The analysis of DVHs revealed clinically minor dosimetric differences between 0.5 cm and 1 cm width MLCs. Dosimetric indices, i.e., Planed Target Volume (PTV) coverage, conformity and inhomogeneity, presented simple quantitative measures of the plans width different MLC leaf width. Almost identical target coverage and similar dose distributions among the critical structures were observed in both H&N, prostate and spine patients. Interestingly, it was found that the dosimetric accuracy of plans generated with 1.0 cm leaf width MLC was superior than those with 0.5 cm leaf width.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Kubo et al., “Impact of Collimator Leaf Width on Stereotactic Radiosurgery and 3D Conformal Radiation Therapy Treatment Plans”, IJROBP Vol. 44, No. 4, pp. 937–945, 1999.
Zhu et al., “Intensity Modulated Radiation Therapy for Mesothelioma: Impact of MLC Leaf Width and Pencil Beam Size on Planning Quality and Delivery Efficiency”, IJROBP Vol. 62, No. 5, pp. 1525–1534, 2005.
Burmeister et al., “Effect of MLC Leaf Width on the Planning and Delivery of SMLC IMRT using the CORVUS Inverse Treatment Planning System”, Medical Physics Vol. 31, No.12, 2004.
Fiveash et al., “Effect of MLC Leaf Width on Physical Dose Distributions in the Treatment of CNS and Head and Neck Neoplasms with IMRT”, Medical Physics Vol. 29, No. 6, 2002.
** et al., “Dosimetric Study using Different Leaf-width MLCs for Treatment Planning of Dynamic Conformal Arcs and Intensity Modulated Radiosurgery”, Medical Physics Vol. 32, No.2, 2005.
Nill et al., “IMRT with MLC of Different Leaf Widths: a Comparison of Achievable Dose Distribution”, Radiotherapy and Oncology 75, pp. 106–111, 2005.
Wang et al., “Stereotactic IMRT for Prostate Cancer: Dosimetric Impact of MLC Leaf Width in the Treatment of Prostate Cancer with IMRT”, Journal of Applied Clinical Medical Physics, Vol. 5, No.2, pp. 29–41, Spring 2004.
Wang et al., “Dosimetric Advantage and Clinical Implication of A Micro-MLC in the Treatment of Prostate Cancer with IMRT”, Medical Dosimetry, Vol. 30, No.2, pp. 97–103, 2005.
Baltas et al. “A Conformal Index (COIN) to Evaluate Implant Quality and Dose Specification in Brachytherapy”, IJROBP Vol. 40, No. 25, pp. 515–524, 1998.
Mapcheck Manual, Sun Nuclear Corp.
Kim et al., “Potential Uncertainty — Information that was forgotten”, Proceedings of XIVth International Conference of Using Computer in Radiation Therapy”, pp. 139–141, 2004.
** et al., “A novel dose uncertainty model and its application for dose verification”, Medical Physics 32(6), 1747–1756.
Author information
Authors and Affiliations
Corresponding author
Editor information
Rights and permissions
Copyright information
© 2007 International Federation for Medical and Biological Engineering
About this paper
Cite this paper
Su, Z., Kim, S., Liu, C., Palta, J. (2007). Is Dosimetric Effect of Leaf Width of MLC Clinically Significant in IMRT. In: Magjarevic, R., Nagel, J.H. (eds) World Congress on Medical Physics and Biomedical Engineering 2006. IFMBE Proceedings, vol 14. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-36841-0_437
Download citation
DOI: https://doi.org/10.1007/978-3-540-36841-0_437
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-36839-7
Online ISBN: 978-3-540-36841-0
eBook Packages: EngineeringEngineering (R0)