Differences Between Planned And Delivered Bowel Dose In Tomotherapy For Hepatocellular Carcinoma Patients

Purpose/Objective(s)To evaluate changes of delivered bowel dose due to organ movement during tomotherapy for hepatocellular carcinoma.Materials/MethodsWe selected hepatocellular carcinoma patient whose tumor was located in segment V and VI. Fifty-one Gy in 20 fractions was prescribed to the high-risk planning target volume by Tomotherapy Hi-Art planning system (Wisconsin, USA). The organ at risk volume containing stomach, duodenum and small bowel at levels between upper margin of the first lumbar vertebrate and the lower margin of the third lumbar vertebrate was defined as a bowel region. After each treatment session, mega-voltage computed tomography (MVCT) images were fused with the planning CT images and a bowel region was contoured and compared with the initial bowel region. Congruity between bowel regions for 20 treatment sessions were analyzed(co-volume^2/ (volume 1 ∗ volume 2). Using adaptive planning software from the Tomotherapy planning system, verification doses to bowel regions were analyzed, and high-dose volume (1.8∼2.7 Gy/fr), mid-dose volume (1.0∼1.8 Gy/fr) and low-dose volume (0∼1.0 Gy/fr) were defined.ResultsThe mean value of congruity between bowel region from the planning CT and bowel regions from MVCT was 88.99 ± 5.5%. Assessment of differences between planned and delivered bowel dose resulted in high-dose, mid-dose and low-dose volumes of 7.75 ± 4.45%, 2.91 ± 1.4% and 9.85 ± 3.43%, respectively. High-dose, mid-dose, low-dose volumes seemed to correspond to peri-hepatic, para-vertebral and peri-splenic bowel regions, repectively. Large discrepancy in the high-dose volume may have resulted from motion of GTV in the liver, while diaphragmatic movement and peristalsis in the peri-splenic free space may have contributed to discrepancy in the low-dose volume.ConclusionsThe changes of delivered bowel dose due to organ movement for hepatocellular carcinoma were substantial at High-dose and Low-dose volume area. Helical tomotherapy, MVCT, Adaptive radiotherapy, Hepatoma, Organ motion. Purpose/Objective(s)To evaluate changes of delivered bowel dose due to organ movement during tomotherapy for hepatocellular carcinoma. To evaluate changes of delivered bowel dose due to organ movement during tomotherapy for hepatocellular carcinoma. Materials/MethodsWe selected hepatocellular carcinoma patient whose tumor was located in segment V and VI. Fifty-one Gy in 20 fractions was prescribed to the high-risk planning target volume by Tomotherapy Hi-Art planning system (Wisconsin, USA). The organ at risk volume containing stomach, duodenum and small bowel at levels between upper margin of the first lumbar vertebrate and the lower margin of the third lumbar vertebrate was defined as a bowel region. After each treatment session, mega-voltage computed tomography (MVCT) images were fused with the planning CT images and a bowel region was contoured and compared with the initial bowel region. Congruity between bowel regions for 20 treatment sessions were analyzed(co-volume^2/ (volume 1 ∗ volume 2). Using adaptive planning software from the Tomotherapy planning system, verification doses to bowel regions were analyzed, and high-dose volume (1.8∼2.7 Gy/fr), mid-dose volume (1.0∼1.8 Gy/fr) and low-dose volume (0∼1.0 Gy/fr) were defined. We selected hepatocellular carcinoma patient whose tumor was located in segment V and VI. Fifty-one Gy in 20 fractions was prescribed to the high-risk planning target volume by Tomotherapy Hi-Art planning system (Wisconsin, USA). The organ at risk volume containing stomach, duodenum and small bowel at levels between upper margin of the first lumbar vertebrate and the lower margin of the third lumbar vertebrate was defined as a bowel region. After each treatment session, mega-voltage computed tomography (MVCT) images were fused with the planning CT images and a bowel region was contoured and compared with the initial bowel region. Congruity between bowel regions for 20 treatment sessions were analyzed(co-volume^2/ (volume 1 ∗ volume 2). Using adaptive planning software from the Tomotherapy planning system, verification doses to bowel regions were analyzed, and high-dose volume (1.8∼2.7 Gy/fr), mid-dose volume (1.0∼1.8 Gy/fr) and low-dose volume (0∼1.0 Gy/fr) were defined. ResultsThe mean value of congruity between bowel region from the planning CT and bowel regions from MVCT was 88.99 ± 5.5%. Assessment of differences between planned and delivered bowel dose resulted in high-dose, mid-dose and low-dose volumes of 7.75 ± 4.45%, 2.91 ± 1.4% and 9.85 ± 3.43%, respectively. High-dose, mid-dose, low-dose volumes seemed to correspond to peri-hepatic, para-vertebral and peri-splenic bowel regions, repectively. Large discrepancy in the high-dose volume may have resulted from motion of GTV in the liver, while diaphragmatic movement and peristalsis in the peri-splenic free space may have contributed to discrepancy in the low-dose volume. The mean value of congruity between bowel region from the planning CT and bowel regions from MVCT was 88.99 ± 5.5%. Assessment of differences between planned and delivered bowel dose resulted in high-dose, mid-dose and low-dose volumes of 7.75 ± 4.45%, 2.91 ± 1.4% and 9.85 ± 3.43%, respectively. High-dose, mid-dose, low-dose volumes seemed to correspond to peri-hepatic, para-vertebral and peri-splenic bowel regions, repectively. Large discrepancy in the high-dose volume may have resulted from motion of GTV in the liver, while diaphragmatic movement and peristalsis in the peri-splenic free space may have contributed to discrepancy in the low-dose volume. ConclusionsThe changes of delivered bowel dose due to organ movement for hepatocellular carcinoma were substantial at High-dose and Low-dose volume area. Helical tomotherapy, MVCT, Adaptive radiotherapy, Hepatoma, Organ motion. The changes of delivered bowel dose due to organ movement for hepatocellular carcinoma were substantial at High-dose and Low-dose volume area. Helical tomotherapy, MVCT, Adaptive radiotherapy, Hepatoma, Organ motion.