PMID- 28645509
OWN - NLM
STAT- MEDLINE
DCOM- 20180509
LR  - 20191210
IS  - 1873-4022 (Electronic)
IS  - 1873-4022 (Linking)
VI  - 42
IP  - 3
DP  - 2017 Autumn
TI  - A fast and reliable method for daily quality assurance in spot scanning proton 
      therapy with a compact and inexpensive phantom.
PG  - 238-246
LID - S0958-3947(17)30054-7 [pii]
LID - 10.1016/j.meddos.2017.05.001 [doi]
AB  - In a radiotherapy center, daily quality assurance (QA) measurements are performed 
      to ensure that the equipment can be safely used for patient treatment on that 
      day. In a pencil beam scanning (PBS) proton therapy center, spot positioning, 
      spot size, range, and dose output are usually verified every day before 
      treatments. We designed, built, and tested a new, reliable, sensitive, and 
      inexpensive phantom, coupled with an array of ionization chambers, for daily QA 
      that reduces the execution times while preserving the reliability of the test. 
      The phantom is provided with 2 pairs of wedges to sample the Bragg peak at 
      different depths to have a transposition on the transverse plane of the depth 
      dose. Three "boxes" are used to check spot positioning and delivered dose. The 
      box thickness helps spread the single spot and to fit a Gaussian profile on a low 
      resolution detector. We tested whether our new QA solution could detect errors 
      larger than our action levels: 1 mm in spot positioning, 2 mm in range, and 10% 
      in spot size. Execution time was also investigated. Our method is able to 
      correctly detect 98% of spots that are actually in tolerance for spot positioning 
      and 99% of spots out of 1 mm tolerance. All range variations greater than the 
      threshold (2 mm) were correctly detected. The analysis performed over 1 month 
      showed a very good repeatability of spot characteristics. The time taken to 
      perform the daily quality assurance is 20 minutes, a half of the execution time 
      of the former multidevice procedure. This "in-house build" phantom substitutes 2 
      very expensive detectors (a multilayer ionization chamber [MLIC] and a strip 
      chamber, reducing by 5 times the cost of the equipment. We designed, built, and 
      validated a phantom that allows for accurate, sensitive, fast, and inexpensive 
      daily QA procedures in proton therapy with PBS.
CI  - Copyright (c) 2017 American Association of Medical Dosimetrists. Published by 
      Elsevier Inc. All rights reserved.
FAU - Bizzocchi, Nicola
AU  - Bizzocchi N
AD  - Azienda Provinciale per i Servizi Sanitari (APSS) Protontherapy Department, 
      Trento, Italy.
FAU - Fracchiolla, Francesco
AU  - Fracchiolla F
AD  - Azienda Provinciale per i Servizi Sanitari (APSS) Protontherapy Department, 
      Trento, Italy. Electronic address: Francesco.Fracchiolla@apss.tn.it.
FAU - Schwarz, Marco
AU  - Schwarz M
AD  - Azienda Provinciale per i Servizi Sanitari (APSS) Protontherapy Department, 
      Trento, Italy; INFN-TIFPA, Trento, Italy.
FAU - Algranati, Carlo
AU  - Algranati C
AD  - Azienda Provinciale per i Servizi Sanitari (APSS) Protontherapy Department, 
      Trento, Italy.
LA  - eng
PT  - Evaluation Study
PT  - Journal Article
DEP - 20170620
PL  - United States
TA  - Med Dosim
JT  - Medical dosimetry : official journal of the American Association of Medical 
      Dosimetrists
JID - 8908862
SB  - IM
MH  - Humans
MH  - *Phantoms, Imaging
MH  - *Proton Therapy
MH  - Quality Assurance, Health Care
OTO - NOTNLM
OT  - Daily QA phantom
OT  - Pencil beam scanning
OT  - Proton therapy
OT  - Quality assurance
EDAT- 2017/06/25 06:00
MHDA- 2018/05/10 06:00
CRDT- 2017/06/25 06:00
PHST- 2016/07/13 00:00 [received]
PHST- 2017/03/15 00:00 [revised]
PHST- 2017/05/19 00:00 [accepted]
PHST- 2017/06/25 06:00 [pubmed]
PHST- 2018/05/10 06:00 [medline]
PHST- 2017/06/25 06:00 [entrez]
AID - S0958-3947(17)30054-7 [pii]
AID - 10.1016/j.meddos.2017.05.001 [doi]
PST - ppublish
SO  - Med Dosim. 2017 Autumn;42(3):238-246. doi: 10.1016/j.meddos.2017.05.001. Epub 
      2017 Jun 20.