Investigation And Analysis On The Performance And Protection Of 33 CT In Suzhou

Objective:Through the investigation of the quality control and radiation protection effect around 33 CT machine and room in Suzhou by two testing agencies,to understand the protection situation and performance of medical CT machine and room in Suzhou;compare the differences in quality control level among the various CT manufacturers;compare the differences in measurement by the two testing agencies;discuss the influence factors of the medical CT performance and the radiation level around the room;reveals the problems when test the medical CT performance and the radiation level around the room;to provide the protection technology support for medical radiation workers,patients and the public health rights;to provide the basis for strengthen the management of radiation treatment and ensure the quality and safety of medical treatment.Methods:according to the methods and requirements of "quality assurance testing specification of X-ray computed tomography devices "GB17589-2011,"Radiation protection requirements of X ray computer tomography "GBZ165-2012,"Basic standard of radiation protection and radiation sources' safety " GB18871-2002,"Diagnosis and protection requirements of medical X-ray radiation " GBZ 130-2013,Assign the investigation tasks equally to two testing agencies in Suzhou.The investigation tasks including the medical CT field investigation,measurement of the CT performance and the radiation level around CT room,and collect related data of CT.Analysis the data,research the dose distribution around the CT room,and explore the influence factors of medical CT performance index and radiation levels around the CT room;reveal the relevant of the radiation dose among the related person,medical CT performance index and CT room;compare the consistency among the different testing agencies.Results:After sampling inspect the CT room radiation levels around 33 hospitals,some parts of 3 hospital' CT rooms were found to be(first one is the 30cm distance to the door of CT control room control room,the second one is the 30cm distance to the protection door of the machine room,the last one is 30cm distance to the protective wall of CT room)well above the national standard which is 2.5 mu Sv/h.Other parts are in line with national standard.The radiation protection qualified rate is 91%.The 11 indexes of sampling CT performance among the 33 hospitals were meet the requirements of CT national quality control standard.The passing rate was 100%;According to the requirements of CT accepted standards,the qualified rate of the reconstruction thickness deviation,CT dose index(CTDI),the CT value of water,noise,high contrast resolution and low contrast detect-ability were 79%,67%,91%,88%,85%and 97%respectively.CT performance index of different manufacturers are different.Among the four manufacturers of SIEMENS,GE,PHILIPS and TOSHIBA,SIEMENS has the optimal positioning accuracy.TOSHIBA has good performance at the CT value of the water and noise.The two testing agencies use the same type of equipment,the test results are comparable,otherwise the test results have some systematic deviations.Conclusion:(1)The radiation dose rate around X-ray CT room in Suzhou are basically accord with the control target value and requirements of "Radiation protection requirements of X ray computer tomography"GBZ165-2012 and the year limited dose limit requirements for staff and the public of "Basic standard of radiation protection and radiation sources' safety";In the peripheral part of the CT room,there is insufficient shielding,which is not only the defect of the early design and construction,but also the defect of maintenance management.(2)The quality control of CT in Suzhou is in line with the requirements of "quality assurance testing specification of X-ray computed tomography devices " GB17589-2011.(3)There are obvious differences in the quality control of some CT produced by different manufacturers.(4)In the data of some performance detection indicators,the differences between different testing agencies are mainly due to the poor consistency of performance detection equipment.