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KMID : 1164220120240020157
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Journal of Korean Society for Radiotherapeutic Technology
2012 Volume.24 No. 2 p.157 ~ p.165
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Usefulness of Abdominal Compressor Using Stereotactic Body Radiotherapy with Hepatocellular Carcinoma Patients
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Kim Joo-Ho
Kim Jun-Won
Baek Jong-Geal
Park Kwang-Soon
Lee Jong-Min
Son Dong-Min
Lee Sang-Kyu
Jeon Byeong-Cheol
Cho Jung-Heui
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Abstract
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Purpose: We evaluated usefulness of abdominal compressor for stereotactic body radiotherapy (SBRT) with unresectable hepatocellular carcinoma (HCC) patients and hepato-biliary cancer and metastatic liver cancer patients.
Materials and Methods: From November 2011 to March 2012, we selected HCC patients who gained reduction of diaphragm movement ＞1 cm through abdominal compressor (diaphragm control, elekta, sweden) for HT (Hi-Art Tomotherapy, USA). We got planning computed tomography (CT) images and 4 dimensional (4D) images through 4D CT (somatom sensation, siemens, germany). The gross tumor volume (GTV) included a gross tumor and margins considering tumor movement. The planning target volume (PTV) included a 5 to 7 mm safety margin around GTV. We classified patients into two groups according to distance between tumor and organs at risk (OAR, stomach, duodenum, bowel). Patients with the distance more than 1 cm are classified as the 1st group and they received SBRT of 4 or 5 fractions. Patients with the distance less than 1 cm are classified as the 2nd group and they received tomotherapy of 20 fractions. Megavoltage computed tomography (MVCT) were performed 4 or 10 fractions. When we verify a MVCT fusion considering priority to liver than bone-technique. We sent MVCT images to Mim_vista (Mimsoftware, ver .5.4. USA) and we re-delineated stomach, duodenum and bowel to bowel_organ and delineated liver. First, we analyzed MVCT images to check the setup variation. Second we compared dose difference between tumor and OAR based on adaptive dose through adaptive planning station and Mim_vista.
Results: Average setup variation from MVCT was －0.66±V1.53 mm (left-right) 0.39±?4.17 mm (superior-inferior), 0.71±?1.74 mm (anterior-posterior), －0.18±T0.30 degrees (roll). 1st group (d≥1) and 2nd group (d＜1) were similar to setup variation. 1st group (d≥1) of Vdiff3% (volume of 3% difference of dose) of GTV through adaptive planing station was 0.78±?0.05%, PTV was 9.97±?3.62%, Vdiff5% was GTV 0.0%, PTV was 2.9±a0.95%, maximum dose difference rate of bowel_organ was －6.85±?1.11%. 2nd Group (d＜1) GTV of Vdiff3% was 1.62±0.55%, PTV was 8.61±? 2.01%, Vdiff5% of GTV was 0.0%, PTV was 5.33±)2.32%, maximum dose difference rate of bowel_organ was 28.33±?24.41%.
Conclusion: Despite we saw diaphragm movement more than 5 mm with flouroscopy after use an abdominal compressor, average setup_variation from MVCT was less than 5 mm. Therefore, we could estimate the range of setup_error within a 5 mm. Target’s dose difference rate of 1st group (d≥1) and 2nd group (d＜1) were similar, while 1st group (d≥1) and 2nd group (d＜1)’s bowel_organ’s maximum dose difference rate’s maximum difference was more than 35%, 1st group (d≥1)’s bowel_organ’s maximum dose difference rate was smaller than 2nd group (d＜1). When applicating SBRT to HCC, abdominal compressor is useful to control diaphragm movement in selected patients with more than 1 cm bowel_organ distance.
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KEYWORD
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hepatocellular carcinoma, tomotherapy, stereotactic body radiotherapy, abdominal compressor
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