Comparison of Setup error of isocenter between above and below nipple levels in thoracic and upper abdominal malignancies using KV orthogonal or Cone-beam computed tomography (CBCT) images at Siriraj Hospital
Keywords:
CBCT, isocenter, KV-KV, Setup error, Vac-lokTM, Wing boardAbstract
Background The challenging point in radiotherapy at thoracic and upper abdominal region is the setup error from skin marker due to arm up positioning. The arm up position might not be identical for each day of treatment particularly in case of isocenter close to the arms. Therefore, in this study, we studied the setup error compared between levels of isocenter, above versus below nipple. Objective To study the variations of isocenter shifting from skin marker to bone matching by KV orthogonal (KV-KV) or Cone Beam CT (CBCT) matching in thoracic and upper abdominal radiotherapy with Wing board device and Wing board with Vac-lokTM positioning cushion. Materials and Methods Fifty consecutive patients who underwent thoracic or upper abdomen radiotherapy (lung, esophagus, liver and stomach) with Wing board device and Wing board with Vac-lokTM from June 2014- February 2016 at Siriraj hospital were retrospectively analyzed. The patients were assessed isocenter shifting in Vertical (Vrt.), Longitudinal (Lng.) and Lateral (Lat.) directions from skin marker to bone matching (KV-KV and CBCT imaging) and the patients were divided into two groups by location of isocenter, above versus below nipple. Datasets were statistically analyzed using percentage, mean, standard deviation and t-test. Results The setup error in the longitudinal direction was higher in isocenter above nipple groups, 0.41 cm. vs. 0.32 cm. (p-value 0.041). However, there is no statistical significant difference in setup error among vertical and lateral directions. Conclusion The skin marker and laser setup had significantly more error in longitudinal direction in thoracic and upper abdominal radiotherapy with arm up position with wing board device especially at isocenter above nipple. The possible reason would be due to daily setup uncertainty of arm up positioning.
References
Balter JM, Chen GT, Pelizzari CA, Krishnasamy S, Rubin S, Vijayakumar S. Online repositioning during treatment of the prostate: A study of potential limits and gains. Int J Radiat Oncol Biol Phys. 1993; 27:137-43.
Nelson C, Starkschall G, Chang JY. The potential for dose escalation in lung cancer as a result of systematically reducing magins used to generate planning target volume. Int J Radiat Oncol Biol Phys. 2006; 65:573-86.
de Boer HC, van Sörnsen de Koste JR, Senan S, Visser AG, Heijmen BJ. Analysis and reduction of 3D systematic and random setup errors during the simulation and treatment of lung cancer patients with CT-base external beam radiotheraphy dose planning. Int J Radiat Oncol Biol Phys. 2001; 49:857-68.
Erridge SC, Seppenwoolde Y, Muller SH, van Herk M, De Jaeger K, Belderbos JS, et al. Portal imaging to assess set-up errors, tumor motion and tumor shrinkage during conformal radiotherapy of non-small cell lung cancer. Radiother Oncol. 2003; 66:75-85.
Li W, Moseley DJ, Bissonnette JP, Purdie TG, Bezjak A, Jaffray DA.. Setup reproducibility for thoracic and upper gastrointestinal radiation therapy : influence of immobilization method and on-line conebeam CT guidance. Med Dos. 2010; 35:287-96.
Sutee , D.; Ruj, S.; Apinya, K.; Set up verification and PTV margins determination of rapid arc therapy in prostate cancer using an on-board imager. Siriraj Med. J. 2015; 67(suppl 1):S1-5.
Borst GR, Sonke JJ, Betgen A, Remeijer P, van Herk M, Lebesque JV. Kilo-voltage cone-beam computed tomography setup measurement for lung cancer patients; first clinical results and comparison with electronic portal-imaging device. Int J Radiat Oncol Biol Phys. 2007; 68:555-61.
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