Impact of Breath-Hold Level on Positional Error Aligned by Stent/Lipiodol in Hepatobiliary Radiotherapy with Breath-Hold Respiratory Control
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 (ΔBHL) was defined as the standard deviation in differences between actual BHLs and baseline BHL. Mean BHL, ΔBHL, 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 <1.4 L. Positional errors were similar for patients with ΔBHL<0.03 L and >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.
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Posted 02 Jun, 2020
On 01 Jul, 2020
On 16 Jun, 2020
Received 08 Jun, 2020
On 04 Jun, 2020
Invitations sent on 02 Jun, 2020
On 02 Jun, 2020
Received 02 Jun, 2020
On 25 May, 2020
On 24 May, 2020
On 24 May, 2020
On 24 Apr, 2020
Received 21 Apr, 2020
On 08 Apr, 2020
Received 06 Mar, 2020
Invitations sent on 04 Mar, 2020
On 04 Mar, 2020
On 10 Feb, 2020
On 09 Feb, 2020
On 09 Feb, 2020
Impact of Breath-Hold Level on Positional Error Aligned by Stent/Lipiodol in Hepatobiliary Radiotherapy with Breath-Hold Respiratory Control
Posted 02 Jun, 2020
On 01 Jul, 2020
On 16 Jun, 2020
Received 08 Jun, 2020
On 04 Jun, 2020
Invitations sent on 02 Jun, 2020
On 02 Jun, 2020
Received 02 Jun, 2020
On 25 May, 2020
On 24 May, 2020
On 24 May, 2020
On 24 Apr, 2020
Received 21 Apr, 2020
On 08 Apr, 2020
Received 06 Mar, 2020
Invitations sent on 04 Mar, 2020
On 04 Mar, 2020
On 10 Feb, 2020
On 09 Feb, 2020
On 09 Feb, 2020
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 (ΔBHL) was defined as the standard deviation in differences between actual BHLs and baseline BHL. Mean BHL, ΔBHL, 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 <1.4 L. Positional errors were similar for patients with ΔBHL<0.03 L and >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.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5