Three-dimensional conformal radiotherapy with intensity-modulated radiation beams significantly enhances the ability to produce sharp dose gradients in the boundaries between a tumor and nearby critical structures.Small uncertainties in the daily repositioning of patients can lead to the overdose of the critical structure and the escape of the target volume.It emphasizes the need to improve the ability to localize the target for treatment. And the image-guided radiotherapy was development.Although steady streams of enhanced new methods of imaging are being introduced to improve treatment guidance and treatment verification,the development of kilovoltage cone-beam CT integrated with the medical linear accelerator for the specific purpose of guiding therapy will permit localization and targeting of soft-tissue structures at the time of treatment.In this review,we focus on the clinical application of CT in the image-guided radiotherapy.

Objective To evaluate the impact of different anatomical landmarks on registration in imaging-guided radiation (IGRT) for lung cancer. Methods For 20 patients with non-small cell lung cancer receiving stereotactic body radiotherapy (SBRT) in Fudan University Cancer Hospital, 100 frames of kilo-voltage cone-beam computed tomography scanning were evaluated in this study. The spine, carina and tumor were selected as landmarks for registration, respectively. Results of registration using different landmarks were documented and compared. Results The average set-up errors in the left-right, superiorinferior and anterior-posterior directions were -0. 08 cm ±0. 32 cm, -0. 16 cm ±0. 45 cm and 0. 06 cm ±0. 23 cm with the spine for registration;0. 06 cm ±0. 34 cm, -0. 13 cm ±0. 45 cm and -0. 02 cm±0.23 cm with the carina;and -0. 17 cm ±0.25 cm, 0.03 cm ±0.47 cm and 0. 15 cm ±0.38 cm with tumor. The registration results between using the carina and tumor as landmarks were statistically significant different (q=4.61, P=0. 002 ;q = 2. 23 , P=0. 118;q=3.44, P=0. 017). The registration results were equal when using the spine and tumor as landmarks ( q = 1.85, P = 0. 195; q = 2. 54, P = 0. 075; q = 1.89,P=0. 185), as well as using the carina and tumor as landmarks (q=2.76, P=0. 054;q=0.31, P=0. 826 ;q = 1.55, P = 0. 276). Conclusions For early stage lung cancer, the spine and tumor can be used equally as registration landmarks in imaging-guided SBRT. The carina is not suggested for its poor reproducible position.

Objective To observe the protective effect of asiatic acid on hyperlipidemia golden hamsters induced by high fat diet and explore its mechanism.Methods Hyperlipidemic golden hamsters fed with high-fat diet were administered orally with asiatic acid (8,16,32 mg/kg)for 4 weeks.Levels of serum lipid content,liver histology,hepatic GSH-PX and SOD levels,serum ALT and AST activities were evaluated in golden hamsters,fluorescence quantitative polymerase chain reaction(RT-PCR)is using to examine the liver lecithin cholesterol fatty acyl transferase(LCAT) and class B typeⅠscavenger receptor(SR-BⅠ)mRNA expression. Results Compared with model group,the levels of TC,TG,LDL-C,TC/HDL,ALT and AST in low and mediate asiatic acid groups were all significantly decreased but the levels of SOD and GSH-PX were significantly increased(P<0.01).HE staining results showed that fat deposition in the liver were improved by administration of asiatic acid,and the expression of LCAT and SR-BⅠmRNA were increased.Conclusion Asiatic acid can effectively reduce blood lipid levels,and alleviate liver damage of the hyperlipidemia golden hamsters by lipid regulation and antioxidative ability augmentation.The increased levels of LCAT and SR-BⅠmRNA expression maybe involved in the mechanism of hypolipidaemic effect of asiatic acid.

Objective To observe the injury of some chief organ induced by paraquat (PQ) poisoning in rats, and to explore the mechanism. Method A total of 60 inbred line SD rats were randomly divided into experimental group (n = 30) and control group (n = 30), and each group was further divided into 6 subgroups (n =5) as per the sacrifice of rats at different intervals. The rats of experimental group received the intra-abdominal injection of paraquat (1 mg/mL, 18 mg/kg), and the rats of control group were treated with the same amount of saline solution instead. The rats of each subgroup were sacrificed separately 2 h,6 h, 12 h,24 h,72 h and 120 h after administration of PQ or saline. Lungs, livers and kidneys were taken for histopathological study. Results There was noticeable exudate in lung tissue of rats in experimental group in the early stage. And then the cystic changes in the liver of rats in experimental group were found. A noticeable hemoglobin was found in the renal tubules 24 h after modeling. But the exudation in lung decreased 24 h later, and in the mean time, the disorganization of pulmonary alveoli was obvious and some remarkable collagen appeared in the interstitial tissue of lung, and it was significantly obvious 72 h after modeling. In the liver of rats in experimental group, the injured tissue had some extent of repair in 72 h after modeling, and recovered gradually. But the injury of kidney was exacerbated 72 h after modeling. In the control group, the lung, liver and kidney were not changed in all stages after modeling.Conclusions The paraquat could induce failure of some chief organs in SD rats. The injury was most remarkable in the lung in a progressive way. The kidney injury was not more severe than that of lung tissue, but the pathological changes of the kidney became worse and worse as time taken. The injury of liver induced by paraquat was slight, and the injury could heal up gradually.

Objective To explore the feasibility of delineation of the atherosclerotic plaque in carotid artery using compressed sensing three dimensional motion-sensitized driven equilibrium prepared rapid gradient echo (CS-3D MERGE) technique. Methods Twenty-three patients who underwent carotid endarterectomy (CEA) were enrolled prospectively. In all patients, bilateral carotid arteries were scanned by CS-3D MERGE and contrast-enhanced MR angiography (MRA) simultaneously. Image quality of CS-3D MERGE images was scored. Images from the CS-3D MERGE sequence and contrast-enhanced MRA were used to measure the carotid stenosis, which were divided into four groups:normal group, mild stenosis group, moderate stenosis group, and severe stenosis group. The results were compared between the two methods. And images from the CS-3D MERGE sequence were compared with corresponding histology in identifying major plaque components including lipid rich necrotic core (LRNC), intraplaque hemorrhage (IPH), and calcification (CA). Spearman rank correlation coefficient was used to compare the correlation between the CS-3D MERGE sequence and contrast-enhanced MRA in measuring the carotid stenosis. Agreement was tested comparing images from the CS-3D MERGE sequence with corresponding histology in identifying major plaque components including lipid-rich necrotic core, intraplaque hemorrhage, and calcification. Results Twenty-three CEA patients finished bilateral CS-3D MERGE scanning successfully. Image quality was 3.16±0.25. There was an excellent correlation between CS-3D MERGE and MRA in measuring stenosis (r=0.95, P<0.01). The agreement between CS-3D MERGE and histological results for LRNC detection was 76.2% (16/21). It was less sensitive for IPH detection (71.4%, 15/21). CS-3D MERGE identified all CA accurately (100.0%, 21/21). Sensitivity and specificity were 86.6% (13/15) and 50.0% (3/6) for LRNC, 73.3% (11/15) and 66.6% (4/6) for IPH, 100.0% for CA respectively(16/16, 5/5). Conclusion CS-3D MERGE, a single sequence, can be used to quantify carotid stenosis and plaque components conveniently.

Objective To select the optimal registration method for on-line kilovoltage cone-beam CT (KVCBCT) guided lung cancer radiation and evaluate the reproducibility of the selected method. MethodsSixteen patients with non-small cell lung cancer were enrolled into this study.A total of 96 pre treatment KVCBCT images from the 16 patients were available for the analysis.Image registration methods were bone-based automatic registration,gray-based automatic registration,manual registration and semi-auto matic registration.All registrations were accomplished by one physician.Another physician blindly evaluated the results of each registration,then selected the optimal registration method and evaluated its reproducibili ty.Results The average score of the bone-based automatic registration,gray-based automatic registration, manual registration and semi-automatic registration methods was 2.4,2.7,3.0 and 3.7,respectively.The score of the four different groups had statistics significant difference (F = 42.20,P < 0.001).Using the semi-automatic registration method,the probability of the difference between two registration results more than 3 ram in the left-right,superior-inferior,and anterior-posterior directions was 0,3% and 6% by the same physician,0,14% and 0 by different physicians,and 8%,14% and 8% by physician and radiation therapist.Conclusions Semi-automatic registration method,possessing the highest score and accepted re producibility,is appropriate for KVCBCT guided lung cancer radiation.

Slit lamp adapter is an important optical delivery system of laser photocoagulator. It can transmit laser and change the diameter size of the laser spot. According to the continuable zoom principle of extender lens, using cam mechanical adjust structure to change the diameter size of the laser spot. The diameter size changes from 50 microm to 500 microm.
Fundus Oculi ; Laser Therapy ; instrumentation

Objective To assess the rotational set-up errors in patients with thoracic neoplasms. Methods 224 kilovohage cone-beam computed tomography (KVCBCT) scans from 20 thoracic tumor pa-tients were evaluated retrospectively. All these patients were involved in the research of " Evaluation of the residual set-up error for online kilovohage cone-beam CT guided thoracic tumor radiation". Rotational set-up errors, including pitch, roll and yaw, were calculated by 'aligning the KVCBCT with the planning CT, using the semi-automatic alignment method. Results The average rotational set-up errors were -0.28°±1.52°, 0.21°± 0.91° and 0.27°± 0. 78° in the left-fight, superior-inferior and anterior-posterior axis, respective-ly. The maximal rotational errors of pitch, roll and yaw were 3.5°, 2.7° and 2.2°, respectively. After cor-rection for translational set-up errors, no statistically significant changes in rotational error were observed. Conclusions The rotational set-up errors in patients with thoracic neoplasms were all small in magnitude. Rotational errors may not change after the correction for translational set-up errors alone, which should be e-valuated in a larger sample future.

Objective To assess set-up errors measured with kilovoltage cone-beam CT (KV-CBCT), and the impact of online corrections on margins required to account for set-up variability during IMRT for patients with prostate cancer. Methods Seven patients with prostate cancer undergoing IMRT were enrolled onto the study. The KV-CBCT scans were acquired at least twice weekly. After initial set-up using the skin marks, a CBCT scan was acquired and registered with the planning CT to determine the setup errors using an auto grey-scale registration software. Corrections would be made by moving the table if the setup errors were considered clinically significant ( i. e. , ＞ 2 mm). A second CBCT scan was acquired immediately after the corrections to evaluate the residual error. PTV margins were derived to account for the measured set-up errors and residual errors determined for this group of patients. Results 197 KV-CBCT images in total were acquired. The random and systematic positioning errors and calculated PTV margins without correction in mm were:a) Lateral 3. 1,2. 1,9. 3;b) Longitudinal 1.5, 1.8, 5. 1 ;c) Vertical 4. 2,3.7, 13.0. The random and systematic positioning errors and calculated PTV margin with correction in mm were:a) Lateral 1.1,0. 9, 3.4;b) Longitudinal 0. 7, 1.1, 2. 5;c) Vertical 1.1, 1.3, 3.7. Conclusions With the guidance of online KV-CBCT, set-up errors could be reduced significantly for patients with prostate cancer receiving IMRT. The margin required after online CBCT correction for the patients enrolled in the study would be appoximatively 3-4 mm.

Objective To probe into the relation of expressions of HIF-1α, VEGF and EGFR in esophageal squamous cell carcinoma with radiation therapy efficacy. Methods 73 of the patients with carcinoma of oesophagus from January , 2011 to May , 2014 in the General Hospital of Ningxia Medical University , were involved in this research , their clinical data reviewed and analyzed. Before radiotherapy , immunohistochemical SP was used to test expressions of HIF-1α, VEGF and EGFR in the cancer tissues. Relationships between the expressions and the efficiency of radiotherapy were analyzed. Results The positive expressions of HIF-1α, VEGF and EGFR were 70.0%, 84.9% and 80.8%, respectively. In terms of the single factor analysis related to recent curative effects, HIF-1α expression had significant correlation with recent curative effects (P=0.03). Conversely , multiplicity indicated that HIF-1α and EGFR expressions were notably associated with recent curative effects (P=0.007, 0.045, respectively). Conclusions The positive expressions of HIF-1α,VEGF and EGFR in the esophageal carcinoma may account for a largest proportion of the total. HIF-1α and EGFR expressions are associated with the short-term outcomes.