In this study,the vaporization ratio of the 2-μm laser in the prostatic tissue with benign prostatic hyperplasia was examined in vitro,to explore a technique to estimate the clearance rate of prostatic tissue during the transurethral vaporesection of the prostate.A total of 9 fresh prostatic tissue specimens were obtained by open surgery and the wet weight of the prostatic tissue were measured immediately after the sample collection.Under the simulated conditions of transurethral vaporesection of the prostate by 2-μm laser,each prostate gland was completely vaporesected into fragments with a diameter of less than 1.0 cm in vitro.After the vaporesection,the whole fragments of prostatic tissue were collected and measured.Then the lost weight of prostatic tissue,the weight of the collected prostatic tissue and the ratio of the lost weight of prostatic tissue to the wet weight of the prostate glandular organ specimen were calculated.The correlation between the weight of collected prostatic tissue and the weight of the whole glandular organ was analyzed.All the experimental procedures were carried out by one operator.Wet weight of the prostatic gland specimen and the weight of the harvested prostatic tissues after the procedure were recorded.With respect to the wet weight of prostate gland specimen,the percentage of the weight of collected prostatic tissue was(34.45±1.51)%,and the percentage of the lost weight of prostatic tissue was(65.55±1.51)%.Satisfactory linear relationship was observed between the weight of collected prostatic tissue and the wet weight of prostate gland specimen[y=3.245x-6.475(t=15.097,P=0.000)].It is concluded that under the simulated conditions of transurethrai vaporesection of the prostate by 2-μm laser,the vaporization ratio of prostatic tissue can be calculated on the basis of the weight of collected prostatic tissue,and thereby the clearance of prostatic tissue during the formal operation by 2-μm laser could be quantitatively determined.