Research on interpolation methods in medical image processing.

Image interpolation is widely used for the field of medical image processing. In this paper, interpolation methods are divided into three groups: filter interpolation, ordinary interpolation and general partial volume interpolation. Some commonly-used filter methods for image interpolation are pioneered, but the interpolation effects need to be further improved. When analyzing and discussing ordinary interpolation, many asymmetrical kernel interpolation methods are proposed. Compared with symmetrical kernel ones, the former are have some advantages. After analyzing the partial volume and generalized partial volume estimation interpolations, the new concept and constraint conditions of the general partial volume interpolation are defined, and several new partial volume interpolation functions are derived. By performing the experiments of image scaling, rotation and self-registration, the interpolation methods mentioned in this paper are compared in the entropy, peak signal-to-noise ratio, cross entropy, normalized cross-correlation coefficient and running time. Among the filter interpolation methods, the median and B-spline filter interpolations have a relatively better interpolating performance. Among the ordinary interpolation methods, on the whole, the symmetrical cubic kernel interpolations demonstrate a strong advantage, especially the symmetrical cubic B-spline interpolation. However, we have to mention that they are very time-consuming and have lower time efficiency. As for the general partial volume interpolation methods, from the total error of image self-registration, the symmetrical interpolations provide certain superiority; but considering the processing efficiency, the asymmetrical interpolations are better.

An LC-MS/MS method for determination of forsythiaside in rat plasma and application to a pharmacokinetic study.

A highly sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of forsythiaside in rat plasma using epicatechin as internal standard. The analytes were extracted by solid-phase extraction and chromatographied on a C(18) column eluted with a gradient mobile phase of acetonitrile and water both containing 0.2% formic acid. The detection was performed by negative ion electrospray ionization in multiple reaction monitoring mode, monitoring the transitions m/z 623-->161 and m/z 289-->109 for forsythiaside and epicatechin, respectively. The assay was linear over the concentration ranges of 2.0-50.0 and 50.0-5000.0ng/mL with limits of detection and quantification of 0.2 and 1.0ng/mL, respectively. The precision was <10.8% and the accuracy was >91.9%, and extraction recovery ranged from 81.3% to 85.0%. This method was successfully applied to a pharmacokinetic study of forsythiaside in rats after intravenous (20mg/kg) and oral (100mg/kg) administration, and the result showed that the compound was poorly absorbed with an absolute bioavailability being approximately 0.5%.

[Alternating magnetic field damages the reproductive function of murine testes].

OBJECTIVE: To explore the relationship between physical and biological effects of alternating magnetic field and study the influence of the magnetic field on the reproductive function of murine testes. METHODS: Thirty ICR mice were randomized into 5 groups: normal control, X-ray radiation, weak magnetic field (1000 Hz), 1 h strong magnetic field and 2 h strong magnetic field (2000 Hz). The mice were sacrificed at 7 days after the exposure for the analysis of testicular sperm motility, observation of histopathological changes in the testis by HE staining and evaluation of the changes by modified Johnsen grade criteria. RESULTS: The rates of sperm motility were (42.37 +/- 10.24)% in the normal control group, (39.00 +/- 12.35)% in the X-ray radiation group, (36.00 +/- 17.28)% in the weak magnetic field group, (10.72 +/- 5.67)% in the 1 h strong magnetic field group and (4.44 +/- 2.87)% in the 2 h strong magnetic field group, respectively. Johnsen's scores decreased and the testis damage increased in a dose- and time-dependent manner. CONCLUSION: Magnetic field, either strong or weak, may damage the testis function by inducing injury to seminiferous tubules and Leydig cells, thickening of the basal membrane, derangement, exfoliation, massive apoptosis and necrosis of spermatogenic cells in the lumen, situation of the epididymis, and consequently the absence of sperm.

[Effect of early rehabilitation training on radiation-induced trismus in nasopharyngeal carcinoma patients].

BACKGROUND & OBJECTIVE: Many nasopharyngeal carcinoma (NPC) patients could survive for a long time after radiotherapy. But the complications of radiotherapy, such as trismus, severely influence the quality of life of NPC patients. This study was to observe the effect of early rehabilitation training on radiation-induced trismus of NPC patients. METHODS: A total of 108 NPC patients received rehabilitation guidance by doctors at initial radiotherapy and subjected to early rehabilitation training regularly and intensively after radical radiotherapy between Dec. 2003 and Dec. 2004 at Xiangya Hospital of Central South University. They continued on rehabilitation training out of hospital as the same in hospital. According to the data of rehabilitation training obtained by questionnaire at 1 month after radiotherapy, the patients who completed the amount of rehabilitation training (>or=75%) were brought into rehabilitation training group, the others was brought into control group. The distance between two dens incivus medialis (DDIM) of the patients was measured at 1 month and 1 year after radiotherapy. RESULTS: The difference of rehabilitation training score was significantly higher in rehabilitation training group than in control group (9.80+/-3.02. vs.4.75+/-1.90 at 1 month after radiotherapy, P<0.05û 9.00+/-2.67 vs. 2.20+/-0.82 at 1 year after radiotherapy, P<0.05). The occurrence rates of trismus were 44.1% at 1 month and 51.5% at 1 year after radiotherapy in rehabilitation training group, and 60.0% and 85.0% in control group. The reduction of DDIM was significantly smaller in rehabilitation training group than in control group [(0.50+/-0.48) cm vs. (1.20+/-0.74) cm at 1 month after radiotherapy, P<0.05û (0.58+/-0.62) cm vs. (2.42+/-0.84) cm at 1 year after radiotherapy, P<0.01]. CONCLUSIONS: Early rehabilitation training is helpful to decrease the occurrence of trismus in NPC patients after radiotherapy and improve the quality of life of NPC patients.