Effect of deep inspiration breath-hold technique on dosimetry of target volume and organs at risk in mediastinal lymphoma irradiation / 中华放射肿瘤学杂志

ABSTRACT

Objective Objective To evaluate the effect of deep inspiration breath-hold technique (DIBH) on the dosimetry of target volume and organs at risk (OARs) in mediastinal lymphoma irradiation.Methods This was a prospectively study and five patients with stage Ⅰ and Ⅱ mediastinal lymphomas were included continuously.The absolute target volume,the absolute OAR doses,and the relative doses to volume were compared between DIBH and free-breathing (FB) scans,based on the principles of the affected site irradiation and the butterfly field.The differences were analyzed using paired t test.Results The median age of these five patients was 30 years.Compared with FB scan,DIBH scan led to significant decreases in the gross tumor volume (GTV)(Δ=29.4 cm3,P=0.006) and the planning target volume (PTV)(Δ=322 cm3,P=0.005) before chemotherapy,while no significant difference in clinical target volume (CTV) was found.Meanwhile,the lung volume of DIBH scan was significantly increased (mean Δ=1456 cm3,P=0.001),while the heart width of DIBH scan was significantly reduced (Δ=1.3 cm,P=0.012),as compared with those of FB scan.The mean doses to the lung and heart were significantly lower in DIBH scan than in FB scan (heart8.5±4.7 Gy vs.11.6±4.7 Gy,P=0.022;lung7.6±1.1 Gy vs.11.6±1.4 Gy,P=0.000).The absolute target volume of the heart was significantly reduced at V15 and above in DIBH scan than in FB scan (all P<0.05).Relative doses to volume of the lung and heart were significantly reduced at each dose level (from V5 to V35) in DIBH scan than in FB scan (all P<0.05).Conclusions DIBH technique can significantly reduce PTV,enlarge lung volume,and reduce the mean dose and relative doses to volume of the lung and heart at each level (from V5 to V35) compared with FB scan in mediastinal lymphoma radiation.