ABSTRACT
Objective To investigate the effect of different additional filtration thickness of DSA on image quality and radiation dose with cerebral angiography. Methods Prospective collected 90 patients with DSA examination of the whole cerebral artery, patients were divided into A, B and C group according to the time of the examination, each group included 30 cases. Patients underwent conventional DSA, the additional filtration of group A, B and C were (1.0 mmAl+0.1 mmCu), (1.0 mmAl+0.4 mmCu) and (1.0 mmAl+0.9 mmCu), respectively. Dose area product (DAP), air kerma (AK), tube current and tube voltage of anteroposterior and lateral radiography of the whole brain were recorded, and scored the image quality. Eye lens organ dose values were obtained by using simulation phantom and LiF dosemeter under A, B and C groups with three different additional filtrations for cerebral angiography. The image quality scores and the radiation dosewere analyzed by one-way ANOVA tests or Kruskal-Wallis tests. Results The image quality comprehensive score of three groups showed significant difference (F=40.07,P<0. 01), which were (3.8±0.4), (3.6 ± 0.5) and (3.0 ± 0.6), respectively. The DAP and AK value of anteroposterior and lateral radiography of three groups also showed significant difference (P<0.05), B and C group were lower than the A group. Left and right eye lens organ dose were decreased along with the increase of the additional filtration thickness, and the difference between the 3 groups also had significant difference (P<0.01). Conclusion Both the image quality and radiation dose can acquire when conducted the whole brain DSA with 1.0 mmAl+0.4 mmCu additional filtration.
ABSTRACT
Objective To measure and analyze the radiation dose for patients undergoing nuclear medicine examination,and to characterize radiation exposure of patients by using the estimated effective dose.Methods Patients undergoing nuclear medicine examinations were classified and the radiation doses from radiopharmaceuticals to patients were measured and calculated.Meanwhile,radiation exposure from computed tomography (CT) procedure was calculated on the basis of CT protocols and patients' information.The effective doses to patient from both the radiopharmaceutical and CT scan radiation were calculated and the factors influencing patient radiation doses were analyzed.Results For the patients undergoing positron emission tomography-computed tomography (PET-CT) examination,the average effective doses from positron radiopharmaceutical 18F-fluorodeoxyglucose (18F-FDG),18F-fluoro-l-thymidine (18 F-FLT),11C-choline,11 C-methylmethionine (11 C-MET) and 11 C-acetate (11 C-Ac) were (5.06 ± 0.73),(4.74±1.29),(1.71 ±0.05),(3.18±0.69) and (1.08±0.19) mSv,respectively.CTscan caused average effective dose was (8.80 ± 0.58) mSv.If a full diagnostic CT investigation was performed,the effective dose might be up to 27 mSv.Whereas for emission computed tomography (ECT) examinations,the average effective dose to the patients irradiated by single photon radiopharmaceutical 99Tcm-methylenediphosphonate (99Tcm-MDP),99Tcm-macroaggregated albumin (99Tcm-MAA),99Tcm-diethylentriaminpentaacetic acid (99 Tcm-DTPA),99Tcm-methoxyisobutyl isonitrile (99 Tcm-MIBI) and 99Tcm-pyrophosphate (99Tcm-PYP) were (4.63 ± 0.01),(1.71 ± 0.01),(1.18 ± 0.01),(7.19 ± 0.03) and (4.18 ± 0.01) mSv,respectively.Conclusions Radiopharmaceutical irradiation caused effective dose to the patients undergoing nuclear medicine examinations is from 1.08 to 7.19 mSv,while CT scan cause average effective dose is 8.80 mSv in PET-CT examination.