PMID- 37722712
OWN - NLM
STAT- MEDLINE
DCOM- 20240313
LR  - 20240313
IS  - 2473-4209 (Electronic)
IS  - 0094-2405 (Linking)
VI  - 51
IP  - 3
DP  - 2024 Mar
TI  - Range shift verification in spot scanning proton therapy using gamma electron 
      vertex imaging.
PG  - 1985-1996
LID - 10.1002/mp.16739 [doi]
AB  - BACKGROUND: In proton therapy, a highly steep distal dose penumbra can be 
      utilized for dose conformity, given the Bragg peak characteristic of protons. 
      However, the location of the Bragg peak in patients (i.e., the beam range) is 
      very sensitive to range uncertainty. Even a small shift of beam range can produce 
      a significant variation of delivered dose to tumor and normal tissues, thus 
      degrading treatment quality and threatening patient safety. This range 
      uncertainty issue, therefore, is one of the important aspects to be managed in 
      proton therapy. PURPOSE: For better management of range uncertainty, range 
      verification has been widely studied, and prompt gamma imaging (PGI) is 
      considered one of the promising methods in that effort. In this context, a PGI 
      system named the gamma electron vertex imaging (GEVI) system was developed and 
      recently upgraded for application to pencil-beam scanning (PBS) proton therapy. 
      Here, we report the first experimental results using the therapeutic spot 
      scanning proton beams. METHODS: A homogeneous slab phantom and an anthropomorphic 
      phantom were employed. Spherical and cubic planning target volumes (PTVs) were 
      defined. Various range shift scenarios were introduced. Prompt gamma (PG) 
      measurement was synchronized with beam irradiation. The measured PG distributions 
      were aggregated to improve the PG statistics. The range shift was estimated based 
      on the relative change of the centroid in the measured PG distribution. The 
      estimated range shifts were analyzed by range shift mapping, confidence interval 
      (CI) estimation, and statistical hypothesis testing. RESULTS: The range shift 
      mapping results showed an obvious measured range shift tendency following the 
      true shift values. However, some fluctuations were found for spots that had 
      still-low PG statistics after spot aggregation. The 99% CI distributions showed 
      clearly distributed range shift measurement data. The overall accuracy and 
      precision for all investigated scenarios were 0.36 and 0.20 mm, respectively. The 
      results of one-sample t-tests confirmed that every shift scenario could be 
      observed up to 1 mm of shift. The ANOVA results proved that the measured range 
      shift data could be discriminated from one another, except for 16 (of 138) 
      comparison cases having 1-2 mm shift differences. CONCLUSIONS: This study 
      demonstrated the feasibility of the GEVI system for measurement of range shift in 
      spot scanning proton therapy. Our experimental results showed that the proton 
      beam can be measured up to 1 mm of range shift with high accuracy and precision. 
      We believe that the GEVI system is one of the most promising PGI systems for in 
      vivo range verification. Further research for application to more various cases 
      and patient treatments is planned.
CI  - (c) 2023 American Association of Physicists in Medicine.
FAU - Kim, Sung Hun
AU  - Kim SH
AD  - Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of 
      Korea.
FAU - Jeong, Jong Hwi
AU  - Jeong JH
AD  - Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of 
      Korea.
FAU - Ku, Youngmo
AU  - Ku Y
AD  - Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea.
FAU - Lee, Se Byeong
AU  - Lee SB
AD  - Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of 
      Korea.
FAU - Shin, Dongho
AU  - Shin D
AD  - Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of 
      Korea.
FAU - Lim, Young Kyung
AU  - Lim YK
AD  - Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of 
      Korea.
FAU - Kim, Haksoo
AU  - Kim H
AD  - Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of 
      Korea.
FAU - Kim, Chan Hyeong
AU  - Kim CH
AD  - Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea.
LA  - eng
PT  - Journal Article
DEP - 20230918
PL  - United States
TA  - Med Phys
JT  - Medical physics
JID - 0425746
RN  - 0 (Protons)
SB  - IM
MH  - Humans
MH  - *Proton Therapy/methods
MH  - Electrons
MH  - Protons
MH  - Radiotherapy Planning, Computer-Assisted/methods
MH  - Diagnostic Imaging
MH  - Phantoms, Imaging
MH  - Radiotherapy Dosage
OTO - NOTNLM
OT  - beam range verification
OT  - prompt gamma imaging
OT  - proton therapy
EDAT- 2023/09/19 00:43
MHDA- 2024/03/13 06:46
CRDT- 2023/09/18 20:13
PHST- 2023/08/28 00:00 [revised]
PHST- 2023/01/06 00:00 [received]
PHST- 2023/08/29 00:00 [accepted]
PHST- 2024/03/13 06:46 [medline]
PHST- 2023/09/19 00:43 [pubmed]
PHST- 2023/09/18 20:13 [entrez]
AID - 10.1002/mp.16739 [doi]
PST - ppublish
SO  - Med Phys. 2024 Mar;51(3):1985-1996. doi: 10.1002/mp.16739. Epub 2023 Sep 18.