Optimisation of user-selectable volumetric modulated arc therapy (VMAT) planning parameters: VMAT arcs for prostate and head-and-neck cancers.

Abstract

OBJECTIVE:

To evaluate different VMAT planning techniques for a multi-leaf collimator (MLC)providing maximum aperture of 21 × 16 cm².

METHODS:

A VMAT planning study of nine prostate and nine head-and-neck cancer patients was carried out. The patients were previously treated with Intensity Modulated Radiotherapy (IMRT) technique during 2014-15, at radiation oncology SanBortolo Hospital, Vicenza, Italy. Three VMAT plans for each of prostate and head-and-neck cancer patient were optimized using Pinnacle treatment planning system for 6MV photon beam from ElektaSynergyS®Linac system. Single arc, dual arc and combined two independent-single-arcs were optimized for collimator angle 45°. VMAT treatment planning comparison was made among single-arc dual-arc and combined two independent-single-arcs. The student's t-test (two-sided) with p ≤ 0.05 was applied for significant difference between dose volume indices of plans.

RESULTS:

All VMAT techniques produced clinically acceptable plans for prostate, while for head-and-neck, DA and ISAs significantly improved target coverage compared to SA. Single arc is sufficient for prostate, while inefficient in case of head-and-neck dose-planning. In spite of having different VMAT optimization approach dual arc and two combined independent-single-arcs provided very similar target coverage, while dual arc improved sparing of organs-at-risk. Similar treatment delivery times were observed for DA and ISAs VMAT techniques.

CONCLUSIONS:

Single arc is sufficient for prostate, while inefficient in case of head-and-neck dose-planning. Dual arc and two combined independent-single-arcs provided similar PTV coverage, while DA provided better sparing of organs at risk.

• Authors: Ghulam Murtaza, Zaheer Abbas Gillani, Shahid Mehmood, Jalil-Ur-Rehman, Ehsan Ullah Khan
• Journal: JPMA. The Journal of the Pakistan Medical Association (J Pak Med Assoc) Vol. 71 Issue 4 Pg. 1093-1099 (Apr 2021) ISSN: 0030-9982 [Print] Pakistan
• PMID: 34125749 (Publication Type: Journal Article)

Topics

• Head and Neck Neoplasms (radiotherapy)
• Humans
• Male
• Prostate
• Radiotherapy Dosage
• Radiotherapy Planning, Computer-Assisted
• Radiotherapy, Intensity-Modulated