ObjectiveTo investigate the feasibility and superiority of video-assisted minithoracotomy surgery (VAMT) in treatment of adolescent patients with primary spontaneous pneumothorax. MethodsThe clinical data of 103 adolescent patients with spontaneous pneumothorax were analyzed retrospectively. VAMTS was performed in 56 cases and video-assisted thoracoseopic surgery(VATS) was performed in 47 cases. complications Statistical analysis were undergoing in middle-operation, post-operation and ambi-operation in the two groups were analyzed. ResultsNo statistically significant difference were found in blood loss ,operating time,pain grade, out-of-bed activity time, antibiotics use time,chest drainage time,hospital day pulmonary infection between the two groups( all P ＞0.05 ). The cost of hospitalization was lower in VAMTS group compare to VATS group ( P ＜ 0.05). ConclusionVAMT in treatment of adolescent patients with primary spontaneous pneumothorax had the advantage of simple performance, reliable effectiveness, practical,lower cost of hospitalization fee.

Objective To study the accuracy of collapsed cone convolution ( CCC) and anisotropic analytical algorithm ( AAA) in dosimetric calculation on the air cavity interface. Methods A BEAMnrc/EGSnrc Monte Carlo ( MC ) simulation was performed on a Varian Trilogy linear accelerator. The IBA Dosimetry “blue phantom” 3D scanning system was used to verify the accuracy and reliability of the MC simulation. Central axis depth dose distribution and lateral dose profile in a water?equivalent phantom with variously sized air cavities were calculated by CCC and AAA. The obtained depth dose distribution and lateral dose profile were compared with those by MC simulation and EBT2 film, respectively. Results Both CCC and AAA overestimated the dose on the air cavity interface. In spite of some errors, CCC had a higher accuracy than AAA. The errors were mainly related to computational grid, field size, photon energy, cavity size, and the number of fields. Conclusion Electronic disequilibrium on the air cavity interface should be taken into account when CCC and AAA are used for dosimetric calculation in treatment planning system.

Objective To introduce and evaluate the characteristics of a GyroKnife Digital Cobalt-60 System for stereotactic radiotherapy and radiosurgery in mechanical aspect.Methods To test the radiation safety,the dose rate required for radiation protection was measured by using an ionization survey meter ( Inovision Model 451 B,Cleveland,OH ).Micrometer was used to verify the accuracy of the table in movement and protractor to verify the rotation movement range.The 160 mm diameter polystyrene spherical phantom and film were used in measurement of the radiation Full Width at Half Maximum.And the difference between radiation isocenter and mechanical isocenter was also verified.Results Clinical requirement in radiation protection was met.The maximum error of table movement accuracy was 0.2 cm at Z axis; the maximum error of gantry movement accuracy was 0.1°.For all the collimators,radiation Full Width at Half Maximum ( FWHM ) was 2.55,5.40,10.50,and 18.55 mm and average penumbra was 5.0,12.4,30.1,and 51.5 mm,respectively.The maximum difference between mechanical center and radiation center was 1.41 mm.Conclusions Stereotactic radiotherapy and radiosurgery has good mechanical characteristics and is suitable clinic applications.

Objective To introduce and evaluate the dosimetric characteristics of a GyroKnife cobalt-60 system for radiosurgery.Methods0.015 cm3 and 0.600 cm3 ionization chamber,EDR2 film and semiconductor dosimeter were used to measure the dose rate of center point for the four collimators.The diameter of the four collimators were 5 mm,12 mm,30 mm and 50 mm,respectively.0.015 cm3 ionization chamber was used to test the dose-time linear relationship and dose stability.0.015 cm3 ionization chamber and semiconductor was used to measure the dose error of phantom between treatment planning system (TPS)calculation and measurement.The film was used to measure the error of TPS calculation isodose lines width.ResultsThe results from the four measurement methods have no significant difference for the collimator 50 mm.But for collimator 5 mm great discrepancy appeared.The error between calculation by TPS and the measurement by semiconductor was biggest and the value was 4.8％.Most of the error was within 3.0％.The error of the 50％ isodose line along x-axis was biggest and the value was 4.9 mm,others are all within 2.0 mm.ConclusionThe dosimetric character of this system is suitable for stereotactic radiotherapy.

Objective To characterize the inheritance of erythropoietic protoporphyria (EPP) by detecting the mutations of ferroehelatase (FECH) gene in a Chinese family with EPP. Methods Peripheral blood samples were obtained from 4 patients and 3 unaffected individuals in a family with EPP, as well as from 50 unrelated healthy human controls. PCR was performed to amplify all the 11 exons and flanking sequence of FECH gene followed by direct sequencing. Results A splicing mutation,I.e., IVS3+1G→A, was identified in the proband as well as his symptomatic sister, cousin, grandfather and asymptomatic mother, but not in his asymptomatic father, grandmother, or unrelated healthy controls. The genotypes IVS1-23 T/C and IVS3-48 C/T were noted in the proband, his father, sister, cousin and grandfather, but absent in his mother or grandmother who carried IVS1-23 C/C and IVS3-48 T/T genotypes. Conclusions A novel splicing mutation is found in the FECH gene in a Chinese EPP family, which, together with two lowly expressed alleles IVS1-23T and IVS3-48C, is likely to be responsible for the clinical phenotype of EPP in this family.

Objective To study the preemptive analgesic effect of dexmedetomidine (DEX) combined with ropivacaine in spine posterior approach. Methods A total of 75 patients were randomly divided into three groups: group A(control), group B (DEX infusion until the end of surgery), group C (DEX infusion continued until 24h after operation), and all three groups received local infiltration with ropivacaine around the wound after operation. Results Being compared with group C, the visual analogue scale (VAS) in group B and C was reduced in 6 to 72 h after extubation; the time of ini-tial postoperative analgesia was delayed and the total amount of tramadol was also reduced in group B and C (P<0.05). The level of serum cortisol was decreased in group B and C (P<0.05). Conclusion Continual infusion of DEX com-bined with ropivacaine can significantly reduce postoperative pain and the amount of analgesic for patients with spine posterior approach surgery.