ABSTRACT
Objective To explore the effect of respiratory movement on the dose distribution in the TOMO therapy target area. Methods The motion phantom was used to simulate human respiratory movement. The SNC patient analysis software was used to compare the films of the study group with those of the control group, and the effect of respiratory movement on the dose distribution in the TOMO target area was evaluated by the “pass rate” index. Results Visual observation showed that the distribution of film gray in the head-foot direction (i.e., direction of movement) was significantly different with or without respiratory movement. Film analysis showed that the maximum deviation between the width of the target wrapping curve and the treatment plan value was about 2.4 mm at no respiratory movement and about 27.2 mm at respiratory movement; the penumbra width of the target area was 31 mm (head direction) and 28.5 mm (foot direction) at no respiratory movement and 39.7 mm (head direction) and 37 mm (foot direction) at respiratory movement; the “pass rate” of target dose distribution was only 12.3%. Conclusion Respiratory movement has a great impact on the dose distribution in the TOMO target area in the direction of movement. When making clinical treatment plan, the impact of respiratory movement on the dose distribution in the TOMO target area can not be ignored.
ABSTRACT
Objective To investigate the changes of Notch signaling pathway activity in human pancreatic cancer cell lines (SW1990, BxPC3 )after gemcitabine induction, and to study its relationship with pancreatic cancer resistant to gemcitabine chemotherapy. Methods The pancreatic cancer cell lines SW1990 and BxPC3 were cultured with different concentrations of gemcitabine for 48 hours. The Notch signaling pathway receptors ( Notch1, Notch2, Notch3, Notch4), ligands (Jagged1, Jagged2) and downstream target Hesl mRNAs expression were detected by quantitative real-time PCR (Q-PCR). Protein levels of Hes1 were determined by Western blotting. Results After treatment with 2 μmol/L gemcitabine for 48 hours, the expression of Notch1, Notch2, Notch3, Jagged1, Jagged2 and Hes1 mRNAs in SW1990 cells were 8.26 ±0.48, 39.12 ±4.87, 0.84 ±0.06, 105.8 ± 17.92, 6.59 ±0.32 and 17.30 ±2.96, which were significantly elevated when compared with those without gemcitabine treatment ( 1.02 ± 0. 15, 15.25 ± 1.28, 0. 12 ± 0.02,32.66 ± 1.98, 1.88 ± 0.29 and 5.02 ± 0.64, P < 0.05 or P < 0. 01 ); the expression in BxPC3 cells was 7.87 ±0.59, 109.4 ± 10.98, 0.74 ±0.19, 62.73 ± 13.50, 2.09 ±0.16 and 15.38 ± 1.06, which were significantly elevated when compared with those without gemcitabine treatment ( 1.14 ±0.43, 58.96 ±2.63,0.10 ± 0.02, 16.95 ± 3.79, 0.98 ± 0.02 and 2.04 ± 0.16, P < 0.05 or P < 0.01 ). The expressions of Hes1protein in SW1990 cells after 1, 2 μmol/L gemcitabine treatment for 48 h were 0.30 ±0.03, 0.42 ±0.03;and the expressions in BxPC3 cells were 0.33 ± 0.02, 0.45 ± 0.03, which were significantly increased when compared with those without gemcitabine treatment (0.13 ± 0.01, F = 33.71,0.09 ± 0.02, F = 38.54, P <0.01 ). Conclusions The Notch signaling pathway is significantly activated in pancreatic cancer cells SW1990 and BxPC3 by gemcitabine, which may be one of the mechanisms of chemoresistance.