Impact of breath-hold level on positional error aligned by stent/Lipiodol in Hepatobiliary radiotherapy with breath-hold respiratory control.

ABSTRACT: BACKGROUND:Respiratory motion management with breath hold for patients with hepatobiliary cancers remain a challenge in the precise positioning for radiotherapy. We compared different image-guided alignment markers for estimating positional errors, and investigated the factors associated with positional errors under breath-hold control. METHODS:Spirometric motion management system (SDX) for breath holds was used in 44 patients with hepatobiliary tumor. Among them, 28 patients had a stent or embolized materials (lipiodol) as alignment markers. Cone-beam computed tomography (CBCT) and kV-orthogonal images were compared for accuracy between different alignment references. Breath-hold level (BHL) was practiced, and BHL variation (?BHL) was defined as the standard deviation in differences between actual BHLs and baseline BHL. Mean BHL, ?BHL, and body-related factors were analyzed for the association with positional errors. RESULTS:Using the reference CBCT, the correlations of positional errors were significantly higher in those with stent/lipiodol than when the vertebral bone was used for alignment in three dimensions. Patients with mean BHL >?1.4?L were significantly taller (167.6?cm vs. 161.6?cm, p?=?0.03) and heavier (67.1?kg vs. 57.4?kg, p?=?0.02), and had different positional error in the craniocaudal direction (-?0.26?cm [caudally] vs. +?0.09?cm [cranially], p?=?0.01) than those with mean BHL ?0.03?L. CONCLUSION:Under rigorous breath-hold respiratory control, BHL correlated with body weight and height. With more accurate alignment reference by stent/lipiodol, actual BHL but not breath-hold variation was associated with craniocaudal positional errors.

SUBMITTER: Huang TJ 

PROVIDER: S-EPMC7328270 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature