ABSTRACT
Objective To determine the planning target volume margins of head and neck cancers treated by image guided radiotherapy (IGRT).Methods 464 sets cone beam computed tomography (CBCT) images before setup correction and 126 sets CBCT images after correction were obtained from 51 head and neck cancer patients treated by IGRT in our department.The systematic and random errors were evaluated by either online or offline correction through registering the CBCT images to the planning CT.The data was divided into 3 groups according to the online correction times.Results The isocenter shift were 0.37 mm±2.37 mm, -0.43 mm±2.30 mm and 0.47 mm±2.65 mm in right-left (RL), anterior-posterior (AP) and superior-inferior (SI) directions respectively before correction, and it reduced to 0.08 mm±0.68 mm, -0.03 mm±0.74 mm and 0.03 mm±0.80 mm when evaluated by 126 sets corrected CBCT images.The planning target volume (PTV) margin from clinical target volume (CTV) before correction were:6.41 mm,6.15 mm and 7.10 mm based on two parameter model, and it reduced to 1.78 mm,1.80 mm and 1.97 mm after correction.The PTV margins were 3.8 mm,3.8 mm,4.0 mm;4.0 mm,4.0 mm,5.0 mm and 5.4 mm,5.2 mm,6.1 mm in RL, AP and SI respectively when online-correction times were more than 15 times, 11-15 times,5-10 times.Conclusions CBCT-based on online correction reduce the PTV margin for head and neck cancers treated by IGRT and ensure more precise dose delivery and less normal tissue complications.
ABSTRACT
Objective To observe the differences of the reactive oxygen species(ROS) and mitochondrial membrane potential(??m) in mitochondrial DNA-depleted SK-Hep1 and its parent cells.Methods ?0SK-Hep1 cell line was generated by treating SK-Hep1 with ethidium bromide.Flow cytometry(FCM) and laser scanning confocal microscopy were used to detect ROS and ??m.Results Fluorescence intensity of ROS in ?0SK-Hep1 cells was significantly higher than that of the parent cells(35.5 vs 15.6),and the ??m was lower in ?0SK-Hep1 cells(55.0 vs 65.9).Conclusion ?0SK-Hep1 cells showed elevated ROS and lower ??m.These changes might contribute to the variation of phenotypes.
ABSTRACT
Objective To observe the E cadherin gene abnormality in non small cell lung cancer(NSCLC). Methods E cadherin gene mutations in exons 6, 7, 8 and 9 in 24 cases of non small cell lung cancer were studied by PCR SSCP and DNA sequence analysis. Results Abnormality of the E cadherin gene was found in exon 9 by means of insertion, deletion and mutation in 2 cases. Conclusion Abnormality of E cadherin gene is present in NSCLC by means of insertion and deletion in extracelluar matrix. The main cause of the decrease in epithelial adhesion may be resulted from the abnormality gene change of the E cadherin.