AIM　To study the effect of glucocorticoid acetic acid cortisone on expression of CaM mRNA in hypothalamus-pituitary-adrenal axis (HPAA). METHODS　Using reverse transcription polymerase chain reaction (RT-PCR),the expression of CaM mRNA was measured in HPAA of rats which were injected with acetic acid cortisone. RESULTS　Acetic acid cortisone induced the expression of CaM mRNA in hypothalamus and adrenal respectively, but it had no effect significantly in pituitary. CONCLUSION　These data suggest that CaM mRNA plays important role in the modulation of GC in HPAA.

Objective This study analyzes the effect of the shrinkage of thermoplastic mask on patient positioning. Methods Design of the two test. Test 1:thermoplastic film shrinkage test. Get some thermoplastic film by the size of 10 cm×5 cm, extrude it at a certain rate after heated. Measure the length of thermoplastic film on different time, and calculate the contraction. Test 2:phantom test. Take advantage of head and neck phantom, and simulate the procedure that from making mask for patients to radiation therapy. Measure the off set of isocenter which caused by the contraction of thermoplastic mask. Results The largest shrinkage of thermoplastic had happened in 20 minutes. Different tensile ratio had little effect on the shrinkage. The offset of isocenter which caused by the shrinkage of thermoplastic mask were:LR ( -0?? 1± 0?? 3) mm,SI (-0?? 2±0?? 2) mm, AP (0.6±0?? 4) mm,respectively. There was little change in the course of six weeks ( P= 0.185?0?? 961). Conclusions The cooling time should be more than 20 minutes, when making a mask for the patient. The setup errors which caused by the shrinkage of thermoplastic mask is at an acceptable level on this premise.

AIM To study the effect of glucocorticoid acetic acid cortisone on expression of CaM mRNA in hypothalamus pituitary adrenal axis (HPAA). METHODS Using reverse transcription polymerase chain reaction (RT PCR),the expression of CaM mRNA was measured in HPAA of rats which were injected with acetic acid cortisone. RESULTS Acetic acid cortisone induced the expression of CaM mRNA in hypothalamus and adrenal respectively, but it had no effect significantly in pituitary. CONCLUSION These data suggest that CaM mRNA plays important role in the modulation of GC in HPAA.

Objective To analyze the influencing factors of cone-beam CT (CBCT) imagine registration in lung cancer. Methods From Mar. 2007 to Dec. 2007, 20 patients with lung cancer were treated with IGRT. The imagines of CBCT were collected from 6 to 19 fractions during the patients' radiotherapy. To compare the difference of set-up errors between the two groups according to the distance from the lesion in lung to the centrum. At the same time, CBCT imagines from the first, middle and the last fraction of these patients' radiotherapy were registrated in bone and grey methods by four doctors. The difference of set-up errors between different doctors and registrated methods were compared. Results The mean values of set-up errors were ＜2 mm in the two groups without significant difference (x:-1.31mm vs 0. 10 mm (t=0. 07,P=0.554);y:1.24 mm vs 1.37 mm (t=0. 05,P=0. 652);z: - 1.88mm vs -1.26mm (t= -0. 12,P=0.321)). The mean values of set-up errors were ＜ 1.3 mm in four doctors and registrated methods without significant difference, for bone registration,x: -0. 05 mm, -0. 01 mm,0. 05 mm, -0.12 mm and -1.31 mm ( F=-0.01,P=0.887) ;y:0.56 mm,0.35 mm,0.51 mm and 0.43 mm (F= -0.01,P=0.880);z: -1.16 mm, -1.20 mm, -0.88 mm and -1.03 mm (F= -0.04,P=0. 555 ), for grey registration ,x: -0.32 mm, -0.341 mm, -0.395 mm and - 0.37 mm(F=-0.01, P=0.874);y:0.34 mm,0.54 mm, -0.04 mm and 0.27 mm (F= -0.03,P=0.622);x:-1.12 mm,- 1.15 mm, - 1.13 mm and - 1.04 mm (F=0. 00,P=0. 812). Conclusions With the same registrated box and imagine quality, the location of the lesions in lung, registred methods and different doctors are not the influencing factors for CBCT imagine registration.

Objective To study the value of image-guided radiotherapy (IGRT) in lung cancer. Methods From Mar. 2007 to Dec. 2007,58 patients with lung cancer were treated with IGRT. Set-up er-rors in each axial direction was calculated based on IGRT images of each patient. The change of GTV was e-valuated on both cone-beam CT and CT simulator images. Results Twenty-two patients with left lung cane-er,30 with right lung cancer,5 with mediastinal lymphanode metastasis and one with vertebra metastasis were included. The set-up error in x,y and z axes was (0.02±0.26) cm, (0.14±0.49) cm and ( -0. 13± 0.27) cm, respectively,while the rotary set-up error in each axis was -0.15°± 1.59°, -0.01°± 1.50° and 0.12°±1.08°, respectively. The set-up errors were siguifieantly decreased by using of IGRT. GTV movement was observed in 15 patients (25.9%) ,including 5 with left upper lung cancer. GTV moving to the anterior direction was observed in 9 patients,including 4 with]eft upper lung cancer. GTV reduced in 23 (44.2%) patients during treatment. Asymmetric GTV reduction of 22 lesions was observed,with a mean re-ductive volume of 4.9 cm3. When GTV began to shrink,the irradiation dose was 4 -46 Gy,with 20 -30 Gy in 9 patients. Conclusions The use of IGRT can significantly reduce set-up errors. GTV movement and reduction are observed in some cases. The time to modify the target volume needs to be further studied.

Objective To evaluate the effect of setup errors upon the target area and the organs at risk (OAR) during radiotherapy for prostate cancer.Methods Twelve prostate cancer patients receiving treatment in the recent 1 year were randomly recruited in this study.The position of each patient was verified by using cone beam CT (CBCT) for 6-10 times during the treatment.In treatment planning system (TPS),the isocenter position was moved along the setup errors with averaging error value (Plan_A) and each CBCT value (Plan_F).The dose distribution was recalculated without changing the beam setting,weight factors and monitor units (MUs).The dose difference was statistically compared between the simulation and original plans (Plan_O).Results For clinical target volume (CTV) D95,there was a significant difference between Plan_A and Plan_O (P =0.008),whereas no significant difference was observed between Plan_F and Plan_O.There were significant differences between Plan_F and Plan_O,Plan_A and Plan_O (P=0.004,and 0.041) for the planned target volume (PTV) D95.For OAR,rectal V60,Dmax,left femoral V20,Dmax and right femoral Dmax significantly differed between Plan_F and Plan_O (P=0.026,0.015,0.041,0.049,0.003).However,only left femoral Dmax significantly differed between Plan_A and Plan_O (P=0.045).The movement in the superior-inferior (SI) direction was significantly correlated with the changes in the rectal V40,V50 and V60 and PTV D95 (r=-0.785,-0.887,-0.833,0.682).The movement in the anterior-posterior (AP) direction was significantly associated with the variations in the bladder V20,V30,V40,V50 and V60(r=-0.945,-0.823,-0.853,-0.818,-0.774).The evaluation indexes of all normal tissues in the re-plan could meet the clinical requirements.However,the volume of target prescription volume had different levels of deficit,and the deficit of Plan_F was greater than that of Plan_A.Conclusions The simulation results of averaging into the TPS underestimates the effect of daily setup errors on the dose distribution.The effect of setup errors on the dose distribution in target area is greater than that of normal tissues.Y-direction errors are more likely to cause the variations of the rectal and PTV dose,and the errors in the z-direction are inclined to cause the changes in the bladder dose.

Objective To evaluate the effect of the tolerance table of different couch positions in the record and verify system (R&V system) upon the setup accuracy.Methods Clinical data of 715 patients (15 743 fractions of treatment) were extracted from the R&V system database and assigned into four categories including thorax and abdomen,head and neck,breast,and rectum based on the disease site and immobilization device.The first day couch position (FstD) and cumulative average couch position (CumA)were utilized as the references to analyze the couch setup of each faction of treatment,and to establish the tolerance tables of different sites.The sensitivity and specificity of two methods were evaluated by the actual clinical treatment record of the patients.Results For the FstD as the reference,the couch tolerance in the breast was significantly higher than those in other parts.When the CumA was used as the reference,the couch tolerance tended to be stable after a certain fractions of treatment,and the tolerance of all sites was less than that of the FstD.The tolerance tables significantly differed between these two methods (P=0.000).Both two methods possessed high specificity,whereas the CumA method yielded higher sensitivity than the FstD approach.Conclusion Setting a reasonable tolerance table of couch position can effectively improve the setup accuracy.