TY - JOUR
T1 - Organ motion in pediatric high-risk neuroblastoma patients using four-dimensional computed tomography
AU - Kannan, Sneha
AU - Teo, Boon Keng Kevin
AU - Solberg, Timothy
AU - Hill-Kayser, Christine
N1 - Publisher Copyright:
© 2017 The Authors.
PY - 2017
Y1 - 2017
N2 - Purpose/objective(s): High-risk neuroblastoma (HR-NBL) requires multimodality treatment, including external beam radiation of the primary tumor site following resection. Radiotherapy planning must take into account motion of the target and adjacent normal anatomy, both of which are poorly understood in the pediatric population, and which may differ significantly from those in adults. Methods/materials: We examined 4DCT scans of 15 consecutive pediatric patients treated for HR-NBL, most with tumors in the abdominal cavity. The diaphragm and organs at risk were contoured at full inhale, full exhale, and on free-breathing scans. Maximum displacement of organs between full inhale and full exhale was measured in the anterior, posterior, superior, inferior, left, and right directions, as was displacement of centroids in the A/P, S/I, and L/R axes. Contours on free-breathing scans were compared to those on 4D scans. Results: Maximum displacement was along the S/I axis, with the superior aspects of organs moving more than the inferior, implying organ compression with respiration. Liver and spleen exhibited the largest motion, which correlated strongly with the S/I motion of the diaphragm. The maximum organ motion observed in the abdomen and thorax were 4.5 mm and 7.4 mm, respectively, while maximum diaphragm displacement was 5.7 mm. Overall findings mirrored observations in adults, but with smaller magnitudes, as expected. No consistent margins could be added to the free-breathing scans to encompass the motion determined using 4DCT. Conclusions: Organ motion within the pediatric abdomen and pelvis is similar to that observed in adults, but with smaller magnitude. Precise margins to accommodate motion are patient-specific, underscoring the need for 4DCT scanning when possible.
AB - Purpose/objective(s): High-risk neuroblastoma (HR-NBL) requires multimodality treatment, including external beam radiation of the primary tumor site following resection. Radiotherapy planning must take into account motion of the target and adjacent normal anatomy, both of which are poorly understood in the pediatric population, and which may differ significantly from those in adults. Methods/materials: We examined 4DCT scans of 15 consecutive pediatric patients treated for HR-NBL, most with tumors in the abdominal cavity. The diaphragm and organs at risk were contoured at full inhale, full exhale, and on free-breathing scans. Maximum displacement of organs between full inhale and full exhale was measured in the anterior, posterior, superior, inferior, left, and right directions, as was displacement of centroids in the A/P, S/I, and L/R axes. Contours on free-breathing scans were compared to those on 4D scans. Results: Maximum displacement was along the S/I axis, with the superior aspects of organs moving more than the inferior, implying organ compression with respiration. Liver and spleen exhibited the largest motion, which correlated strongly with the S/I motion of the diaphragm. The maximum organ motion observed in the abdomen and thorax were 4.5 mm and 7.4 mm, respectively, while maximum diaphragm displacement was 5.7 mm. Overall findings mirrored observations in adults, but with smaller magnitudes, as expected. No consistent margins could be added to the free-breathing scans to encompass the motion determined using 4DCT. Conclusions: Organ motion within the pediatric abdomen and pelvis is similar to that observed in adults, but with smaller magnitude. Precise margins to accommodate motion are patient-specific, underscoring the need for 4DCT scanning when possible.
KW - 4DCT
KW - Neuroblastoma
KW - Organ motion
KW - Pediatric
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U2 - 10.1002/acm2.12012
DO - 10.1002/acm2.12012
M3 - Article
C2 - 28291918
AN - SCOPUS:85013078166
SN - 1526-9914
VL - 18
SP - 107
EP - 114
JO - Journal of applied clinical medical physics
JF - Journal of applied clinical medical physics
IS - 1
ER -