PMID- 38260830
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20240124
IS  - 2234-943X (Print)
IS  - 2234-943X (Electronic)
IS  - 2234-943X (Linking)
VI  - 13
DP  - 2023
TI  - Simulating an intra-fraction adaptive workflow to enable PTV margin reduction in 
      MRIgART volumetric modulated arc therapy for prostate SBRT.
PG  - 1325105
LID - 10.3389/fonc.2023.1325105 [doi]
LID - 1325105
AB  - PURPOSE: This study simulates a novel prostate SBRT intra-fraction 
      re-optimization workflow in MRIgART to account for prostate intra-fraction motion 
      and evaluates the dosimetric benefit of reducing PTV margins. MATERIALS AND 
      METHODS: VMAT prostate SBRT treatment plans were created for 10 patients using 
      two different PTV margins, one with a 5 mm margin except 3 mm posteriorly 
      (standard) and another using uniform 2 mm margins (reduced). All plans were 
      prescribed to 36.25 Gy in 5 fractions and adapted onto each daily MRI dataset. An 
      intra-fraction adaptive workflow was simulated for the reduced margin group by 
      synchronizing the radiation delivery with target position from cine MRI imaging. 
      Intra-fraction delivered dose was reconstructed and prostate DVH metrics were 
      evaluated under three conditions for the reduced margin plans: Without motion 
      compensation (no-adapt), with a single adapt prior to treatment (ATP), and lastly 
      for intra-fraction re-optimization during delivery (intra). Bladder and rectum 
      DVH metrics were compared between the standard and reduced margin plans. RESULTS: 
      As expected, rectum V18 Gy was reduced by 4.4 +/- 3.9%, D1cc was reduced by 12.2 +/- 
      6.8% (3.4 +/- 2.3 Gy), while bladder reductions were 7.8 +/- 5.6% for V18 Gy, and 9.6 
      +/- 7.3% (3.4 +/- 2.5 Gy) for D1cc for the reduced margin reference plans compared to 
      the standard PTV margin. For the intrafraction replanning approach, average 
      intra-fraction optimization times were 40.0 +/- 2.9 seconds, less than the time to 
      deliver one of the four VMAT arcs (104.4 +/- 9.3 seconds) used for treatment 
      delivery. When accounting for intra-fraction motion, prostate V36.25 Gy was on 
      average 96.5 +/- 4.0%, 99.1 +/- 1.3%, and 99.6 +/- 0.4 for the non-adapt, ATP, and 
      intra-adapt groups, respectively. The minimum dose received by the prostate was 
      less than 95% of the prescription dose in 84%, 36%, and 10% of fractions, for the 
      non-adapt, ATP, and intra-adapt groups, respectively. CONCLUSIONS: Intra-fraction 
      re-optimization improves prostate coverage, specifically the minimum dose to the 
      prostate, and enables PTV margin reduction and subsequent OAR sparing. Fast 
      re-optimizations enable uninterrupted treatment delivery.
CI  - Copyright (c) 2024 Snyder, Smith, Aubin, Shepard and Hyer.
FAU - Snyder, Jeffrey
AU  - Snyder J
AD  - Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa 
      City, IA, United States.
FAU - Smith, Blake
AU  - Smith B
AD  - Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa 
      City, IA, United States.
FAU - Aubin, Joel St
AU  - Aubin JS
AD  - Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa 
      City, IA, United States.
FAU - Shepard, Andrew
AU  - Shepard A
AD  - Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa 
      City, IA, United States.
FAU - Hyer, Daniel
AU  - Hyer D
AD  - Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa 
      City, IA, United States.
LA  - eng
PT  - Journal Article
DEP - 20240108
PL  - Switzerland
TA  - Front Oncol
JT  - Frontiers in oncology
JID - 101568867
PMC - PMC10800949
OTO - NOTNLM
OT  - MR-linac
OT  - MRIgRT
OT  - VMAT (volumetric modulated arc therapy)
OT  - adaptive
OT  - intra-fraction
OT  - prostate SBRT treatment
OT  - tracking
COIS- DH has received consulting fees, and travel support from Elekta AB for work not 
      related to this study. JS and JSA have received Honoria and travel support from 
      Eletka AB which is not related to this work. The remaining authors declare that 
      the research was conducted in the absence of any commercial or financial 
      relationships that could be constructed as a potential conflict of interest.
EDAT- 2024/01/23 12:42
MHDA- 2024/01/23 12:43
PMCR- 2023/01/01
CRDT- 2024/01/23 10:40
PHST- 2023/10/20 00:00 [received]
PHST- 2023/12/18 00:00 [accepted]
PHST- 2024/01/23 12:43 [medline]
PHST- 2024/01/23 12:42 [pubmed]
PHST- 2024/01/23 10:40 [entrez]
PHST- 2023/01/01 00:00 [pmc-release]
AID - 10.3389/fonc.2023.1325105 [doi]
PST - epublish
SO  - Front Oncol. 2024 Jan 8;13:1325105. doi: 10.3389/fonc.2023.1325105. eCollection 
      2023.