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Title: SU-F-T-343: Dosimetric Investigation for Fluence Smoothing On VMAT Plans in Monaco for Head - Neck Cancers

Abstract

Purpose: The study investigates the effect of fluence smoothing parameter on VMAT plans for ten head-neck cancer patients using Monaco5.00.04. Methods: VMAT plans were created using Monaco5.00.04 planning system for 10 head-neck patients. Four plans were generated for each patient using available smoothing parameters i.e. high, medium, low and off. The number of monitor units required to deliver 1 cGy was defined as a modulation degree; and was taken as a measure of plan complexity. Routinely used plan quality parameters Conformity index (CI) and Homogeneity index (HI) were used in the study. As a protocol our center, practices “medium” smoothing for clinical implementation. Plans with medium smoothing were opted as reference plans due to the clinical acceptance and dosimetric verifications made on these plans. Plans were generated by varying the smoothing parameter and re-optimization was done. The PTV was evaluated for D98%, D95%, D50%, D1% and prescription isodose volume (PIV). For critical organs; spine and parotids the parameters recorded were D1cc and Dmean respectively. Results: The cohort had the median prescription as 6000 cGy in the range of 6600 cGy - 4500 cGy. The modulation degree was observed to increase up to 6% from reference to the most complex plan.more » High smoothing had about 11% increase in segments which marginally (0.5 to 1%) increased the homogeneity index while conformity index remains constant. For spine the maximum D1cc was observed in medium smoothing as 4639.8 cGy, this plan was clinically accepted and dosimetrically verified. Similarly for parotids, the Dmean was 2011.9 cGy and 1817.05 cGy. Conclusion: The sensitivity of plan quality in terms of smoothing options (high, medium, low and off) available in Monaco 5.00.04 was resulted in minimal difference in terms of target coverage, conformity index and homogeneity index. Similarly changing smoothing did not result in any enhanced advantage in sparing of critical organs.« less

Authors:
; ; ; ; ; ;  [1]
  1. FORTIS Memorial Research Institute, Gurgaon, Haryana (India)
Publication Date:
OSTI Identifier:
22648945
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; CRITICAL ORGANS; MONACO; NEOPLASMS; OPTIMIZATION; PATIENTS; PLANNING; RADIOTHERAPY

Citation Formats

Jassal, K, Sarkar, B, Ganesh, T, Kaur, H, Giri, U, Mohanti, B, and Munshi, A. SU-F-T-343: Dosimetric Investigation for Fluence Smoothing On VMAT Plans in Monaco for Head - Neck Cancers. United States: N. p., 2016. Web. doi:10.1118/1.4956528.
Jassal, K, Sarkar, B, Ganesh, T, Kaur, H, Giri, U, Mohanti, B, & Munshi, A. SU-F-T-343: Dosimetric Investigation for Fluence Smoothing On VMAT Plans in Monaco for Head - Neck Cancers. United States. doi:10.1118/1.4956528.
Jassal, K, Sarkar, B, Ganesh, T, Kaur, H, Giri, U, Mohanti, B, and Munshi, A. Wed . "SU-F-T-343: Dosimetric Investigation for Fluence Smoothing On VMAT Plans in Monaco for Head - Neck Cancers". United States. doi:10.1118/1.4956528.
@article{osti_22648945,
title = {SU-F-T-343: Dosimetric Investigation for Fluence Smoothing On VMAT Plans in Monaco for Head - Neck Cancers},
author = {Jassal, K and Sarkar, B and Ganesh, T and Kaur, H and Giri, U and Mohanti, B and Munshi, A},
abstractNote = {Purpose: The study investigates the effect of fluence smoothing parameter on VMAT plans for ten head-neck cancer patients using Monaco5.00.04. Methods: VMAT plans were created using Monaco5.00.04 planning system for 10 head-neck patients. Four plans were generated for each patient using available smoothing parameters i.e. high, medium, low and off. The number of monitor units required to deliver 1 cGy was defined as a modulation degree; and was taken as a measure of plan complexity. Routinely used plan quality parameters Conformity index (CI) and Homogeneity index (HI) were used in the study. As a protocol our center, practices “medium” smoothing for clinical implementation. Plans with medium smoothing were opted as reference plans due to the clinical acceptance and dosimetric verifications made on these plans. Plans were generated by varying the smoothing parameter and re-optimization was done. The PTV was evaluated for D98%, D95%, D50%, D1% and prescription isodose volume (PIV). For critical organs; spine and parotids the parameters recorded were D1cc and Dmean respectively. Results: The cohort had the median prescription as 6000 cGy in the range of 6600 cGy - 4500 cGy. The modulation degree was observed to increase up to 6% from reference to the most complex plan. High smoothing had about 11% increase in segments which marginally (0.5 to 1%) increased the homogeneity index while conformity index remains constant. For spine the maximum D1cc was observed in medium smoothing as 4639.8 cGy, this plan was clinically accepted and dosimetrically verified. Similarly for parotids, the Dmean was 2011.9 cGy and 1817.05 cGy. Conclusion: The sensitivity of plan quality in terms of smoothing options (high, medium, low and off) available in Monaco 5.00.04 was resulted in minimal difference in terms of target coverage, conformity index and homogeneity index. Similarly changing smoothing did not result in any enhanced advantage in sparing of critical organs.},
doi = {10.1118/1.4956528},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}