TY - JOUR
T1 - Evaluating motion of pancreatic tumors and anatomical surrogates using cine MRI in 0.35T MRgRT under free breathing conditions
AU - Lewis, Benjamin
AU - Guta, Anamaria
AU - Shin, Jaeik
AU - Ji, Zhen
AU - Kim, Jin Sung
AU - Kim, Taeho
N1 - Funding Information:
This research was partially supported by the Alvin J. Siteman Cancer Center through The Foundation for Barnes-Jewish Hospital and the National Cancer Institute (P30 CA091842). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Dr. Jin Sung Kim was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2020R1A4A101661911).
Funding Information:
This research was partially supported by the Alvin J. Siteman Cancer Center through The Foundation for Barnes‐Jewish Hospital and the National Cancer Institute (P30 CA091842). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Dr. Jin Sung Kim was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2020R1A4A101661911).
Publisher Copyright:
© 2023 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.
PY - 2023/6
Y1 - 2023/6
N2 - Treatment tolerability is a significant limitation to pancreatic cancer treatment with radiotherapy due to proximity to highly radiosensitive organs and respiratory motion necessitating expanded target margins. Further, pancreatic tumors are difficult to visualize on conventional radiotherapy systems. Surrogates are often used to locate the tumor but are often inconsistent and do not provide strong positional relations throughout the respiratory cycle. This work utilizes a retrospective dataset of 45 pancreatic cancer patients treated on an MR-Linac system with cine MRI acquired for real-time target tracking. We investigated intra-fraction motion of tumors and two abdominal surrogates, leading to prediction models between the tumor and surrogate. Patient specific motion evaluation and prediction models were generated from 225 cine MRI series acquired during treatment. Tumor contours were used to evaluate the pancreatic tumor motion. Linear regression and principal component analysis (PCA) based models were used to predict tumor position from the anterior-posterior (AP) motion of the abdominal surface, the superior-inferior (SI) motion of the diaphragm, or a combination. Models were evaluated using mean squared error (MSE) and mean absolute error (MAE). Contour analysis showed the average pancreatic tumor motion range was 7.4 ± 2.7 mm and 14.9 ± 5.8 mm in the AP and SI directions, respectively. The PCA model had MSE of 1.4 mm2 and 0.6 mm2, for the SI and AP directions, respectively, with both surrogates as inputs for the models. When only the abdomen surrogate was used, MSE was 1.3 mm2 and 0.4 mm2 in the SI and AP directions, while it was 0.4 mm2 and 1.3 mm2 when only the diaphragm surrogate was used. We evaluated intra-fraction pancreatic tumor motion and demonstrated prediction models between the tumor and surrogate. The models calculated the pancreatic tumor position from diaphragm, abdominal, or both contours within standard pancreatic cancer target margin, and the process could be applied to other disease sites in the abdominothoracic cavity.
AB - Treatment tolerability is a significant limitation to pancreatic cancer treatment with radiotherapy due to proximity to highly radiosensitive organs and respiratory motion necessitating expanded target margins. Further, pancreatic tumors are difficult to visualize on conventional radiotherapy systems. Surrogates are often used to locate the tumor but are often inconsistent and do not provide strong positional relations throughout the respiratory cycle. This work utilizes a retrospective dataset of 45 pancreatic cancer patients treated on an MR-Linac system with cine MRI acquired for real-time target tracking. We investigated intra-fraction motion of tumors and two abdominal surrogates, leading to prediction models between the tumor and surrogate. Patient specific motion evaluation and prediction models were generated from 225 cine MRI series acquired during treatment. Tumor contours were used to evaluate the pancreatic tumor motion. Linear regression and principal component analysis (PCA) based models were used to predict tumor position from the anterior-posterior (AP) motion of the abdominal surface, the superior-inferior (SI) motion of the diaphragm, or a combination. Models were evaluated using mean squared error (MSE) and mean absolute error (MAE). Contour analysis showed the average pancreatic tumor motion range was 7.4 ± 2.7 mm and 14.9 ± 5.8 mm in the AP and SI directions, respectively. The PCA model had MSE of 1.4 mm2 and 0.6 mm2, for the SI and AP directions, respectively, with both surrogates as inputs for the models. When only the abdomen surrogate was used, MSE was 1.3 mm2 and 0.4 mm2 in the SI and AP directions, while it was 0.4 mm2 and 1.3 mm2 when only the diaphragm surrogate was used. We evaluated intra-fraction pancreatic tumor motion and demonstrated prediction models between the tumor and surrogate. The models calculated the pancreatic tumor position from diaphragm, abdominal, or both contours within standard pancreatic cancer target margin, and the process could be applied to other disease sites in the abdominothoracic cavity.
KW - MRgRT
KW - cine MRI
KW - pancreatic tumor
KW - target tracking
UR - http://www.scopus.com/inward/record.url?scp=85153264256&partnerID=8YFLogxK
U2 - 10.1002/acm2.13930
DO - 10.1002/acm2.13930
M3 - Article
C2 - 37073428
AN - SCOPUS:85153264256
SN - 1526-9914
VL - 24
JO - Journal of applied clinical medical physics
JF - Journal of applied clinical medical physics
IS - 6
M1 - e13930
ER -