PMID- 26843236
OWN - NLM
STAT- MEDLINE
DCOM- 20161026
LR  - 20170214
IS  - 2473-4209 (Electronic)
IS  - 0094-2405 (Linking)
VI  - 43
IP  - 2
DP  - 2016 Feb
TI  - Dosimetric and delivery efficiency investigation for treating hepatic lesions 
      with a MLC-equipped robotic radiosurgery-radiotherapy combined system.
PG  - 727-33
LID - 10.1118/1.4939259 [doi]
AB  - PURPOSE: The CyberKnife M6 (CK-M6) Series introduced a multileaf collimator (MLC) 
      for extending its capability from stereotactic radiosurgery/stereotactic 
      radiotherapy (SBRT) to conventionally fractionated radiotherapy. This work is to 
      investigate the dosimetric quality of plans that are generated using MLC-shaped 
      beams on the CK-M6, as well as their delivery time, via comparisons with the 
      intensity modulated radiotherapy plans that were clinically used on a Varian 
      Linac for treating hepatic lesions. METHODS: Nine patient cases were selected and 
      divided into three groups with three patients in each group: (1) the group-one 
      patients were treated conventionally (25 fractions); (2) the group-two patients 
      were treated with SBRT-like hypofractionation (5 fractions); and (3) the 
      group-three patients were treated similar to group-one patients, but with two 
      planning target volumes (PTVs) and two different prescription dose levels 
      correspondingly. The clinically used plans were generated on the eclipse 
      treatment planning system (TPS) and delivered on a Varian Linac (E-V plans). The 
      multiplan (MP) TPS was used to replan these clinical cases with the MLC as the 
      beam device for the CK-M6 (C-M plans). After plans were normalized to the same 
      PTV dose coverage, comparisons between the C-M and E-V plans were performed based 
      on D(99%) (percentage of prescription dose received by 99% of the PTV), 
      D(0.1cm(3)) (the percentage of prescription dose to 0.1 cm(3) of the PTV), and 
      doses received by critical structures. Then, the delivery times for the C-M plans 
      will be obtained, which are the MP TPS generated estimations assuming having an 
      imaging interval of 60 s. RESULTS: The difference in D(99%) between C-M and E-V 
      plans is +0.6% on average (+ or - indicating a higher or lower dose from C-M 
      plans than from E-V plans) with a range from -4.1% to +3.8%, and the difference 
      in D(0.1cm(3)) was -1.0% on average with a range from -5.1% to +2.9%. The PTV 
      conformity index (CI) for the C-M plans ranges from 1.07 to 1.29 with a mean of 
      1.19, slightly inferior to the E-V plans, in which the CI ranges from 1.00 to 
      1.15 with a mean of 1.07. Accounting for all nine patients in three groups, 45% 
      of the critical structures received a lower mean dose for the C-M plans as 
      compared with the E-V plans, and similarly, 48% received a lower maximum dose. 
      Furthermore, the average difference of the mean critical structure dose between 
      the C-M and E-V plans over all critical structures for all patients showed only 
      +2.10% relative to the prescription dose and the similar comparison finds the 
      average difference of the maximum critical structure dose of only +1.24%. The 
      estimated delivery times for the C-M plans on the CK-M6 range from 18 to 24 
      minutes while they are from 7 to 13.7 min for the E-V plans on the Varian Linac. 
      CONCLUSIONS: For treating hepatic lesions, for the C-M plans that are comparable 
      to E-V plans in quality, the times needed to deliver these C-M plans on the CK-M6 
      are longer than the delivery time for the E-V plans on the Varian Linac, but may 
      be clinically acceptable.
FAU - Jin, Lihui
AU  - Jin L
AD  - Department of Radiation Oncology, Fox Chase Cancer Center, 333 Cottman Avenue, 
      Philadelphia, Pennsylvania 19111.
FAU - Price, Robert A
AU  - Price RA
AD  - Department of Radiation Oncology, Fox Chase Cancer Center, 333 Cottman Avenue, 
      Philadelphia, Pennsylvania 19111.
FAU - Wang, Lu
AU  - Wang L
AD  - Department of Radiation Oncology, Fox Chase Cancer Center, 333 Cottman Avenue, 
      Philadelphia, Pennsylvania 19111.
FAU - Meyer, Joshua
AU  - Meyer J
AD  - Department of Radiation Oncology, Fox Chase Cancer Center, 333 Cottman Avenue, 
      Philadelphia, Pennsylvania 19111.
FAU - Fan, James Jiajin
AU  - Fan JJ
AD  - Department of Radiation Oncology, Fox Chase Cancer Center, 333 Cottman Avenue, 
      Philadelphia, Pennsylvania 19111.
FAU - Ma, Chang Ming Charlie
AU  - Ma CM
AD  - Department of Radiation Oncology, Fox Chase Cancer Center, 333 Cottman Avenue, 
      Philadelphia, Pennsylvania 19111.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Med Phys
JT  - Medical physics
JID - 0425746
SB  - IM
MH  - Four-Dimensional Computed Tomography
MH  - Humans
MH  - Liver Neoplasms/diagnostic imaging/*radiotherapy/*surgery
MH  - Particle Accelerators
MH  - Radiometry
MH  - Radiosurgery/*instrumentation
MH  - Radiotherapy Dosage
MH  - Radiotherapy Planning, Computer-Assisted
MH  - *Robotics
EDAT- 2016/02/05 06:00
MHDA- 2016/10/27 06:00
CRDT- 2016/02/05 06:00
PHST- 2016/02/05 06:00 [entrez]
PHST- 2016/02/05 06:00 [pubmed]
PHST- 2016/10/27 06:00 [medline]
AID - 10.1118/1.4939259 [doi]
PST - ppublish
SO  - Med Phys. 2016 Feb;43(2):727-33. doi: 10.1118/1.4939259.