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Biomedical subjects

T He

Publications and source records attributed to T He.

95 records · Page 6Linked to original sources
PubMed1990

[Application of DNA interstrand cross-link assay to estimate the sensitivity of tumor cells to alkylating agents].

Fluorometric method was modified and used to detect DNA interstrand crosslinks (ISC) in tumor cells after treatment with cisplatin. Linear dose-response curve was obtained. The difference of DNA ISC formation between HeLa S3 (containing O6-methylguanine methyltransferase, Mer+) and HeLa MR (devoid of O6-methyguanine methyltransferase, Mer-) cells was studied after treatment with alkylating agent 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU). The survival fraction was also observed in Mer+ and Mer- cells treated with ACNU. It seems that DNA ISC formation may be used as one of the possible criteria in estimating the sensitivity of tumor cells to bifunctional alkylating agent and forecasting the efficacy of tumor chemotherapy.

Cisplatin↗
PubMed1990

[Argon replacing helium in measurement of pulmonary carbon monoxide diffusing capacity, its normal value and clinical application].

Measuring DL COSB of 120 normal subjects by using a gas mixture, in which helium was replaced by argon, we determined the DL COSB mean value, standard deviation and the predicted value formula for both sexes. The lower limit value of DL COSB for normal subjects was defined and the positive diagnostic value investigated. A ratio of actual value to predicted value below 80% was defined as abnormal. With this diagnostic criterion 43 cases of silicosis and diffuse pulmonary interstitial fibrosis were investigated, the positive rate of the cases being 90.70%, with a false positive rate of below 10% for normal subjects, which indicates that this gas mixture and the criterion are applicable for clinical practice.

Adolescent↗
PubMedDate not supplied

CT-based simulation with laser patient marking.

A CT-based simulator has been assembled based on a commercial CT scanner, virtual simulation software developed at the University of North Carolina and a laser drawing device to transfer the radiation portals from the virtual simulator to the patient. The simulation process can be completed in approximately 1 h; under most cases, the treatment portals can be designed and the patient marked in one session. The device has an inherent accuracy of +/- 1 mm. The portal projection accuracy in clinical cases is observed to be better than 2 mm.

Computer Simulation↗
PubMedDate not supplied

Correction for distortion in a beam outline transfer device in radiotherapy CT-based simulation.

In using a CT scanner as a radiation therapy simulator, it would be helpful to be able to transfer the beam outline from the computer plan to the patient's skin. A beam outline transfer device has been constructed and installed on a Siemens' DRH CT scanner gantry. The planned treatment beam geometry from a 3-D computerized simulation and planning system can be projected onto the patient's skin surface accurately and efficiently. The positioning accuracy achieved is within +/- 0.1 cm over a 20 cm x 20 cm field. Integrating the device into the CT scanner, simplifies the device and reduces the cost over an externally mounted device. Two unsuccessful methods to correct the projection distortions are also mentioned. In order to achieve the reported beam outline transfer accuracy, a system based on our empirically derived calibration procedure is described.

Algorithms↗