Feasibility of using intravenous contrast-enhanced computed tomography scans in oesophagus cancers

Abstract

Introduction The goal of this study is to investigate the feasibility of using intravenous contrast-enhanced computed tomography scans in 3-dimensional conformal radiotherapy treatment planning (3DCRT) for oesophagus cancers. Material and methods Eighteen patients treated for esophagus cancer had a 3D scan with (CT_int) and without (CT_no_int) intravenous injection of contrast product. 45 Gy to 50 Gy were planned. Organs at risk (OAR) were contoured on CT_no_int and CT_int. Target volume (PTV) was created on CT_int then copy/paste on CT_no_inj. Treatment planning was done on CT_no_int then copy/paste on CT_int. Esophagus tumors were planned with 3D-CRT using 4 to 5 coplanar beams with 6 or 16 MV energies. The position of the prescription point was kept on both plans. The used algorithm is the algorithm AAA V10 (Varian). 95% (V95), 100% (V100) and 102% (V102) isodoses volumes, min, max and average PTV doses, monitor units (MU), heart and healthy lungs delivered doses were compared. The differences (D), and the standards deviation (SD), between the average values by CT on all the patients were calculated and noted D (SD). The Wilcoxon statistical test was used. Results Results show a weak difference on total MU on both plans: 0.2% (0.7%) (ns). Average differences related to PTV doses are respectively 0.1% (1.1%), 2.4% (16.4%) and −0.1% (0.7%) (ns) for max, min and average doses. The comparison of isodoses volume shows an important standard deviation: 0% (5%) (ns), −2% (30%) and 1% (61%) respectively for V95, V100 and V102. For the heart, the differences are equals to 2% (14%) (ns) and 1% (17%) for V30Gy and V40Gy. No difference was shown concerning healthy lungs delivered doses: 0%(4%), 0% (4%) (ns) and −1% (7%) for V5Gy, V20Gy and V30Gy respectively. Conclusion The study shows no statistical differences between both plans with and without contrast product. As a consequence, treatment planning on an intravenous contrast-enhanced scanner in esophagus cancers is possible without major achievement or the treatment planning quality. The goal of this study is to investigate the feasibility of using intravenous contrast-enhanced computed tomography scans in 3-dimensional conformal radiotherapy treatment planning (3DCRT) for oesophagus cancers. Eighteen patients treated for esophagus cancer had a 3D scan with (CT_int) and without (CT_no_int) intravenous injection of contrast product. 45 Gy to 50 Gy were planned. Organs at risk (OAR) were contoured on CT_no_int and CT_int. Target volume (PTV) was created on CT_int then copy/paste on CT_no_inj. Treatment planning was done on CT_no_int then copy/paste on CT_int. Esophagus tumors were planned with 3D-CRT using 4 to 5 coplanar beams with 6 or 16 MV energies. The position of the prescription point was kept on both plans. The used algorithm is the algorithm AAA V10 (Varian). 95% (V95), 100% (V100) and 102% (V102) isodoses volumes, min, max and average PTV doses, monitor units (MU), heart and healthy lungs delivered doses were compared. The differences (D), and the standards deviation (SD), between the average values by CT on all the patients were calculated and noted D (SD). The Wilcoxon statistical test was used. Results show a weak difference on total MU on both plans: 0.2% (0.7%) (ns). Average differences related to PTV doses are respectively 0.1% (1.1%), 2.4% (16.4%) and −0.1% (0.7%) (ns) for max, min and average doses. The comparison of isodoses volume shows an important standard deviation: 0% (5%) (ns), −2% (30%) and 1% (61%) respectively for V95, V100 and V102. For the heart, the differences are equals to 2% (14%) (ns) and 1% (17%) for V30Gy and V40Gy. No difference was shown concerning healthy lungs delivered doses: 0%(4%), 0% (4%) (ns) and −1% (7%) for V5Gy, V20Gy and V30Gy respectively. The study shows no statistical differences between both plans with and without contrast product. As a consequence, treatment planning on an intravenous contrast-enhanced scanner in esophagus cancers is possible without major achievement or the treatment planning quality.