The role of miR-92a and BCL11b in radiation induced thymic lymphoma in BALB/c mice

Abstract

Objective To compare the differences of the position, volume and matching index (MI) between internal gross tumor volumes ( IGTVs) determined by four methods based on four dimensional CT (4DCT) and three dimensional CT (3DCT) scans during free reathing and IGTV determined hy one method based on 3DCT ssisted with active breathing control. Methods Eighteen patients with peripheral lung cancer underwent 3DCT and 4DCT simulation scans during free hreathing and then underwent 3DCT simulation scans in end inspiration hold ( CTFIH )and end expiration hold ( CTEFH ).IGTVs were acquired using five methods: the gross tumor volme ( GTV) contours from ten respiratory phases were combined into IGTV10; The GTV contours from 0％ and 50％ phases were combined into ICTV2; IGTVMIP was the GTV contour delineated from the maximum intensity projection ( MIP) ; IGTV3D was acquired from the enlargement of 3DCT-based GTV by each spatial direction on the motion amplitude measured in 4DCT; IGTVABC was acquired by combining GTVs from CTEIR and CTEEH. Results In upperlobe group, there were significant differences in centroid position between ICTVABC and IGTV10 in lateral ( LR) , and IGTVMIP in anterio-posterior ( AP) directions respectively (t =- 2. 377,-2. 199, P ＜0. 05) ,and there were significant differences in centroid position between IGTVABC and IGTV2 , IGTV3D in both LR and AP directions (t = - 2. 185 - - 2. 767, P ＜ 0. 05). In lower lobe group, there were significantdifferences in centroid position between IGTVABC and ICTV10, IGTVMIP, IGTV3D in LR direction (t =3. 950 -4. 543 , P＜0. 05). ,Either in the upper lobe group or in the lower lobe group, IGTVABC was smaller than ICTV10 or IGTV3D significantly (Z = - 3. 180 - - 2. 023 , P＜ 0. 05) , and the Mls between ICTVABCand otber IGTVs were larger in the upper lobe group thanin the lower lobe group significantly (Z = -2. 419 -2. 119, P＜0. 05 ) . Conclrrsions IGTVABC is not completely coincide with IGTVs acquired based on 4DCT or 3DCT during free breathing, and the spatial mismatch correlated with the tumor position,the spatial mismatch is more significant for middle-lower lobe tumor than upper lobe tumor. IGTVABC are larger than IGTV2 but smaller than other IGTVs acquired based on 4DCT and IGTV acquired based on 3DCT during free breathing. Key words: Ionizing radiation; Thymic lymphoma; BCL11b; miR-92a