Daily ultrasound-based image-guided targeting for radiotherapy of upper abdominal malignancies.

摘要: Purpose: Development and implementation of a strategy to use stereotactic ultrasound (US)-based imageguided targeting device (BAT) align intensity-modulated radiotherapy (IMRT) target volumes accurately in the upper abdomen. Because outlines such targets may be poorly visualized by US, we present method that uses adjacent vascular guidance structures as surrogates for position. We assessed potential improvement daily repositioning feasibility application. Methods Materials: A total 62 patients were treated sequential tomotherapeutic IMRT between October 2000 June 2003 cholangiocarcinoma gallbladder carcinoma (n 10), hepatocellular liver metastases 11), pancreatic 20), neuroblastoma 3), other abdominal retroperitoneal tumors 8). The (TVs) organs at risk delineated contrast-enhanced CT data sets. Additionally, close anatomic relation TV, or within delineated. Throughout course IMRT, US BAT images acquired during treatment positioning. In addition typically used (e.g., TV dose-limiting risk), contours superimposed onto real-time axial sagittal images, position adjustments, indicated system, performed accordingly. report BAT-derived distribution shifts three principal room axes compared with skin-mark– based setup, well time required perform alignment. capability presented improve alignment was 15 comparing organ fiducial respective simulation control study after suite. Results: 1,337 alignments attempted. not useful 56 setups (4.2%), mainly because limited visibility due variations colonic gastric air. imaging facilitated intrahepatic asthenic patients. mean SD shift from skin mark 4.9 4.35, 6.0 5.31, 6.7 mm x, y, z direction, respectively. magnitude vector threedimensional correction 11.4 7.6 mm. proportion corrected >10, >15, >20 48.9%, 25.1%, 12.7%, directions, three-dimensional displacement, statistically significant (test against zero hypothesis) p <0.0001. most valuable identification branches portal vein, hepatic artery, dilated bile ducts lesions aorta, celiac trunk, superior mesenteric extrahepatic aspects vein system lesions. setup 4.6 min. correlation error assessment scans revealed reduction 14 alignments. average reduction, length vector, 54.4% 26.9%, an observed residual 3.4 sole worsening initial <2 resulted improvements patient ( 0.03). Conclusion: Daily US-guided feasible vast majority attempted setups. This US-based image-guided tumor has been successfully implemented clinical routine. improved accuracy might allow individualized safety margins optional dose escalation. Compared established application prostate radiotherapy, which can directly visualized,