PMID- 34703106
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20211028
IS  - 0971-6203 (Print)
IS  - 1998-3913 (Electronic)
IS  - 0971-6203 (Linking)
VI  - 46
IP  - 3
DP  - 2021 Jul-Sep
TI  - Importance of Beam-Matching between TrueBeam STx and Novalis Tx in Pre-Treatment 
      Quality Assurance Using Portal Dosimetry.
PG  - 211-220
LID - 10.4103/jmp.JMP_12_21 [doi]
AB  - Flexibility and efficiency in a radiotherapy department with different linear 
      accelerators (linacs) can be improved if they are dosimetrically equivalent, and 
      there is no need of plan or patient-specific quality assurance (PSQA) 
      modification. From 2012 to 2017, our institution purchased three Novalis Tx and 
      one TrueBeam STx beam-matched accelerators with the same high-resolution 
      multileaf collimator (MLC). They are matched taking as reference dosimetric data 
      from Novalis Tx SN-5479. We showed the importance of beam-matched dosimetric 
      units by the use of electronic portal image device (EPID) and Delta4 PSQA. It was 
      able to treat patients on a different machine than the machine used for PSQA. 
      Depth dose, beam profiles, output factors, dosimetric leaf gap, and MLC 
      transmission were compared for all energies and linacs. PSQA in all linacs for 30 
      volumetric-modulated arc therapy plans was also compared. Prostate, breast, and 
      head-and-neck cases were selected to consider low, middle, and high plan 
      complexity, respectively. The comparisons were evaluated using EPID and Delta4 
      phantom. Dosimetric differences between the three Novalis Tx and TrueBeam STx in 
      all energies were lower than 1%. The only significant difference was observed in 
      Novalis EPID in middle complexity when the criterion was tighter in distance. 
      This result could be related with the nonsymmetric dose delivery of semi arcs. In 
      all other cases, there were no differences in two different EPID evaluations. 
      However, TrueBeam EPID values were slightly higher than Novalis EPID values. This 
      could be associated with the high-resolution novel diode detector TrueBeam EPID. 
      The dosimetric data indicated that the Novalis Tx and TrueBeam STx are 
      equivalent. PSQA using EPID and Delta4 phantom showed that there are no 
      dosimetric differences in any of the linacs. These results revealed the 
      flexibility performance in PSQA by beam-matching.
CI  - Copyright: (c) 2021 Journal of Medical Physics.
FAU - Rojas-Lopez, Jose Alejandro
AU  - Rojas-Lopez JA
AD  - Department of Physics, Instituto Zunino, Cordoba, Argentina.
FAU - Venencia, Daniel
AU  - Venencia D
AD  - Department of Physics, Instituto Zunino, Cordoba, Argentina.
LA  - eng
PT  - Journal Article
DEP - 20210908
PL  - India
TA  - J Med Phys
JT  - Journal of medical physics
JID - 9441104
PMC - PMC8491317
OTO - NOTNLM
OT  - Beam-matching
OT  - TrueBeam STx
OT  - patient-specific quality assurance
OT  - portal dosimetry
COIS- There are no conflicts of interest.
EDAT- 2021/10/28 06:00
MHDA- 2021/10/28 06:01
PMCR- 2021/07/01
CRDT- 2021/10/27 07:03
PHST- 2021/01/14 00:00 [received]
PHST- 2021/05/27 00:00 [revised]
PHST- 2021/05/27 00:00 [accepted]
PHST- 2021/10/27 07:03 [entrez]
PHST- 2021/10/28 06:00 [pubmed]
PHST- 2021/10/28 06:01 [medline]
PHST- 2021/07/01 00:00 [pmc-release]
AID - JMP-46-211 [pii]
AID - 10.4103/jmp.JMP_12_21 [doi]
PST - ppublish
SO  - J Med Phys. 2021 Jul-Sep;46(3):211-220. doi: 10.4103/jmp.JMP_12_21. Epub 2021 Sep 
      8.