PMID- 36576722
OWN - NLM
STAT- MEDLINE
DCOM- 20230420
LR  - 20230421
IS  - 1526-9914 (Electronic)
IS  - 1526-9914 (Linking)
VI  - 24
IP  - 4
DP  - 2023 Apr
TI  - Radiosurgical treatment of solitary brain metastases using virtual cones with a 
      standard multileaf collimator.
PG  - e13882
LID - 10.1002/acm2.13882 [doi]
LID - e13882
AB  - PURPOSE: The virtual cone has been previously introduced as a novel technique for 
      generating small, spherical dose distributions using a high-definition multileaf 
      collimator (MLC) for functional radiosurgery applications. There has been no 
      reported investigation into adapting this technique to a standard MLC for the 
      treatment of solitary intracranial metastases as an alternative to physical 
      stereotactic cones. This study characterizes the virtual cone technique adapted 
      to a standard 5 mm leaf-width MLC (VC(SD) ). METHODS: VC(SD) dose distributions 
      using MLC leaf gaps of 2-5 mm were generated and isodose sphericity metrics, peak 
      dose gradients, optimal normalization ranges, and achievable field widths were 
      compared to those of 5.0-12.5 mm diameter physical cones. Target sizes feasible 
      to treat were identified and planned for comparison against established 
      techniques using Paddick conformity index (PCI) and dose volume metrics. 
      End-to-end validation of the VC(SD) technique was performed. RESULTS: VC(SD) and 
      physical cones sphericity metrics agree within 3.5% and VC(SD) plans achieved a 
      dose gradient of 21.3% mm(-1) , comparable to 10.0-12.5 mm diameter physical 
      cones. Normalization within the 50%-77% range preserves the optimal dose gradient 
      within 2%⋅mm(-1) and enables the treatment of 5-11 mm diameter planning target 
      volumes (PTVs). Mean PCI for virtual and physical cones was 0.957 and 0.949, 
      which compared favorably against conformal arc and VMAT (0.899 and 0.926). VC(SD) 
      outperformed conformal arc and VMAT for all dose volume metrics, and the mean 50% 
      dose volume differed from physical cones by < 0.5cc for PTVs as small as 
      5 mm. Validation measurements showed 100% of points passing a 2% / 0.5 mm gamma 
      test for all plans. CONCLUSIONS: The VC(SD) technique efficiently generates 
      spherical dose distributions for the treatment of small brain metastases. 
      Characteristics of the VC(SD) dose distributions are sufficiently comparable to 
      those of physical cones to support VC(SD) as an alternative for the treatment of 
      spherical PTVs as small as 5 mm in diameter.
CI  - (c) 2022 The Authors. Journal of Applied Clinical Medical Physics published by 
      Wiley Periodicals, LLC on behalf of The American Association of Physicists in 
      Medicine.
FAU - Lobb, Eric
AU  - Lobb E
AD  - Department of Radiation Oncology, Ascension NE Wisconsin-St. Elizabeth Hospital, 
      Appleton, Wisconsin, USA.
LA  - eng
PT  - Journal Article
DEP - 20221228
PL  - United States
TA  - J Appl Clin Med Phys
JT  - Journal of applied clinical medical physics
JID - 101089176
SB  - IM
MH  - Humans
MH  - *Radiosurgery/methods
MH  - *Radiotherapy, Conformal/methods
MH  - *Brain Neoplasms/surgery/secondary
MH  - Radiotherapy Dosage
MH  - Radiotherapy Planning, Computer-Assisted/methods
MH  - *Radiotherapy, Intensity-Modulated/methods
PMC - PMC10113701
OTO - NOTNLM
OT  - stereotactic radiosurgery
OT  - virtual cone
COIS- None.
EDAT- 2022/12/29 06:00
MHDA- 2023/04/20 06:42
PMCR- 2022/12/28
CRDT- 2022/12/28 11:22
PHST- 2022/12/01 00:00 [revised]
PHST- 2022/06/28 00:00 [received]
PHST- 2022/12/08 00:00 [accepted]
PHST- 2023/04/20 06:42 [medline]
PHST- 2022/12/29 06:00 [pubmed]
PHST- 2022/12/28 11:22 [entrez]
PHST- 2022/12/28 00:00 [pmc-release]
AID - ACM213882 [pii]
AID - 10.1002/acm2.13882 [doi]
PST - ppublish
SO  - J Appl Clin Med Phys. 2023 Apr;24(4):e13882. doi: 10.1002/acm2.13882. Epub 2022 
      Dec 28.