PMID- 31047365
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20191120
IS  - 1876-7982 (Electronic)
IS  - 1876-7982 (Linking)
VI  - 48
IP  - 2
DP  - 2017 Jun
TI  - Analysis of Influence of Errors in Angular Settings of Couch and Collimator on 
      the Dosimetric and Radiobiological Parameters in VMAT Plans.
PG  - 166-177
LID - S1939-8654(16)30131-X [pii]
LID - 10.1016/j.jmir.2016.10.012 [doi]
AB  - OBJECTIVE: To evaluate the impact of couch and collimator angular variations on 
      dose volume histogram (DVH), tumour control probability (TCP), and normal tissue 
      complication probability (NTCP) of the volumetric-modulated arc therapy (VMAT) 
      plans. METHODS: Stereotactic radiosurgery and stereotactic body radiation therapy 
      VMAT plans were generated for three different hypothetical planning target 
      volumes (PTVs) that mimic brain metastases, single brain lesion, and single spine 
      lesion. Thirty routine VMAT plans (10 prostate, 10 head and neck, and 10 brain 
      cases) treated in our clinic were also selected for this study. The plans were 
      generated using an Eclipse Treatment Planning System and delivered using a Clinac 
      iX linear accelerator equipped with a Millennium 120 multileaf collimator. All 
      the plans were generated using two complementary full arcs (with gantry angle 
      from 179 degrees  to 181 degrees  and collimator rotation of 30 degrees  and 330 degrees ) except the brain 
      tumour cases, which used single full arc with collimator rotation of 30 degrees . In all 
      the cases, the couch angle was zero. Impact of the angular variations in the 
      collimator and couch was studied by varying the collimator and couch angular 
      settings by 1 degrees , 2 degrees , and 3 degrees , and creating six erroneous plans corresponding to the 
      original plans. The variation due to these errors on different DVH and 
      radiobiological parameters (TCP, equivalent uniform dose (EUD), and NTCP) of the 
      PTVs and organs-at-risk (OARs) were observed. The relative percentage of 
      difference in these parameters (DeltaD, DeltaTCP, DeltaEUD, and DeltaNTCP) were analysed, and 
      statistical significance was tested. RESULTS: The variation due to collimator 
      misplacement was observed to be larger than the couch misplacement. Furthermore, 
      in both cases, the variation increased as the degree of error increased. Among 
      the DVH parameters, D(98%), D(95%), and V(95Gy) were affected more by the errors 
      than D(2%), D(5%), and D(50%), in both hypothetical and clinical PTVs. In the 
      clinical PTVs, the TCP showed the most variation among all parameters. The DeltaNTCP 
      of the bladder and brain OARs were zero, whereas for head and neck OARs, it was 
      high. CONCLUSIONS: The couch and collimator angular variation has different 
      effects on different planning situations and different parameters. The outcome 
      produced by the errors is specific to the treatment sites.
CI  - Copyright (c) 2016. Published by Elsevier Inc.
FAU - Noufal, Manthala Padannayil
AU  - Noufal MP
AD  - Department of Medical Physics and Radiotherapy, Baby Memorial Hospital, Calicut, 
      India; Department of Physics, Farook College, Calicut, India; University of 
      Calicut, Malappuram, Kerala, India. Electronic address: noufalsh@gmail.com.
FAU - Abdullah, Kallikuzhiyil Kochunny
AU  - Abdullah KK
AD  - Department of Physics, Farook College, Calicut, India; University of Calicut, 
      Malappuram, Kerala, India.
FAU - Niyas, Puzhakal
AU  - Niyas P
AD  - Department of Medical Physics and Radiotherapy, Baby Memorial Hospital, Calicut, 
      India; Department of Physics, Farook College, Calicut, India; University of 
      Calicut, Malappuram, Kerala, India.
FAU - Nambiar, Vishnu Rajan
AU  - Nambiar VR
AD  - Department of Medical Physics and Radiotherapy, Baby Memorial Hospital, Calicut, 
      India.
LA  - eng
PT  - Journal Article
DEP - 20161224
PL  - United States
TA  - J Med Imaging Radiat Sci
JT  - Journal of medical imaging and radiation sciences
JID - 101469694
OTO - NOTNLM
OT  - DVH
OT  - EUD
OT  - NTCP
OT  - TCP
OT  - VMAT
OT  - collimator error
OT  - couch error
EDAT- 2017/06/01 00:00
MHDA- 2017/06/01 00:01
CRDT- 2019/05/04 06:00
PHST- 2016/07/13 00:00 [received]
PHST- 2016/10/12 00:00 [revised]
PHST- 2016/10/25 00:00 [accepted]
PHST- 2019/05/04 06:00 [entrez]
PHST- 2017/06/01 00:00 [pubmed]
PHST- 2017/06/01 00:01 [medline]
AID - S1939-8654(16)30131-X [pii]
AID - 10.1016/j.jmir.2016.10.012 [doi]
PST - ppublish
SO  - J Med Imaging Radiat Sci. 2017 Jun;48(2):166-177. doi: 
      10.1016/j.jmir.2016.10.012. Epub 2016 Dec 24.