ABSTRACT
Objective To evaluate the application value of dual-source CT coronary angiography in low tube voltage setting and the influence of heart rate on image quality and radiation doses.Methods 323 patients suspected of coronary artery disease received retrospective ECG-gating coronary angiography with dual-source CT scanner,who were divided into low tube voltage group (100 kVp,n =201) and conventional voltage group (120 kVp,E group,n =122).No beta-blockers were taken before CT scan.All patients in low tube voltage group were divided into four groups according to the heart rate (HR):group A,HR≤59 beats per minute (bpm),n =50; group B,60≤HR ＜69 bpm,n =64; group C,70≤HR ＜91bpm,n =62;group D,HR ≥ 91 bpm,n =25.All images were transferred to a workstation for further processing.The best R-R interval reconstruction images of all groups were evaluated.The value of pitch,CT volume dosage index(CTDIvol),dose length product(DLP) and effective dose(E)were recorded.The pitch,the score of imaging quality of coronary artery segments and the radiation dose were compared with One-Way ANOVA.The influence of heart rate on image quality and radiation doses of coronary artery was analyzed.Results The value of pitch in groups A-D was 0.24 ± 0.03,0.29 ± 0.04,0.33 ± 0.05,0.38 ± 0.06,respectively,with statistical difference (F =62.57,P ＜ 0.05).The value of CTDIvol in groups A-E was (21.59±7.97),(20.24±6.03),(18.23±7.55),(18.14 ±5.75),(38.62±16.21)mGy,respectively,with statistical difference (F =85.16,P ＜ 0.05).The value of E in group A-E was (5.31 ±2.18),(4.85 ±1.70),(4.49 ± 1.86),(4.37 ±1.50),(8.75 ± 4.07) mSv,respectively,with statistical difference(F =44.83,P ＜ 0.05).The image score was (4.65 ±0.46),(4.55 ± 0.53),(4.55 ±0.53),(4.47 ±0.72),(4.66 ± 0.44) (F =1.89,P ＞ 0.05).Conclusions No beta-blockers was taken before CT scan,and a high quality image could be acquired by using dual-source CT coronary angiography in low tube voltage setting(100 kVp).When the auto ECG-gating is selected,medium and low HR have little influences on radiation dose,while the radiation dose could be decreased significantly at higher HR,but the possibility to obtain the high quality image decreased.
ABSTRACT
Objective To evaluate the role and technical advantages of CT in 125Ⅰseed implantation in the treatment of tumors. Methods CT-guided 125Ⅰ seed implantation in 45 cases of cancer patients treated 57 times in 51 lesions,CT were used to evaluate the progress of lesions after 125Ⅰ seed implantation 1,2,6 months. Results All procedures were once successful and the total effective rate was 74.5% without any serious complications. Fifty CT examinations immediately after implantation showed satisfactorily seeds distribution but seven cases less satisfactorily that include particles overlap,the location is too close to the lesion edge,the larger the radiation cold spots,etc. Follow-up CT reexamination in 1,2 and 6 months demonstrated that CT examinations showed satisfactorily seeds distribution but accurate seeds number,which could be solved by combined with MPR images and the positioning piece. Conclusions CT-guided 125Ⅰ seed implantation treatment of tumors was a safe,reliable and effective minimally invasive treatment. CT in the preoperative treatment of seed implants planning,precise intraoperative guidance,quality assurance and efficacy of postoperative assessment had a greater role and application advantages.
ABSTRACT
BACKGROUND: As a new radiotherapy for malignant tumor, brachytherapy of radioactive seed implantation enables the inter-tissue implantation of radioactive seeds to be applied further with the appearance of seed implantation treatment planning system (TPS), and the gradual consummation of ultrasound and CT-guided precise positioning system.OBJECTIVE: To evaluate the methods, feasibility, safety and efficacy of CT-guided iodine-125 (125I) implantation for malignant tumors.DESIGN: A controlled observation before and after implantation.SETTING: The First People's Hospital of Hefei City.PARTICIPANTS: Twenty-one patients with malignant tumors, who were not suitable for surgical treatments of operation,were selected from the First People's Hospital of Hefei City from January 2004 to March 2005. There were 26 lesions, including 9 lesions of primary unresectable carcinoma and 17 lesions of metastasis tumors.METHODS: Under CT guidance, 125I seeds were implanted into malignant tumor according to TPS, the radioactivity quantum were 22, 26, 30 and 33 MBq per granule. Larger radiation 125I wes suitable for the implantation in the center of a lesion and smaller ones were for the margin of the lesion and the peripheral region of some important organisms such as vessels and nerves. The interval between larger seeds was about 1.5 cm whereas the interval between smaller ones was about 1.0 cm.MAIN OUTCOME MEASURES: The seed distribution, existence of complication and changes of the size of lesion after implantation were observed.RESULTS: ① The seeds were implanted successfully in all the 21 cases. No complication was observed. The practical distribution of the implanted seeds was basically the same as the scheduled scheme before implantation. All the 21 patients were involved in the analysis of results. ② The number of seeds implanted in one lesion was 5 to 40 (mean 14).Pain relief was obtained in all 10 cases of malignant tumors of bone after implantation. Follow-up CT reexamination demonstrated that 18 lesions were obviously diminished, necrosis was found in 4 lesions and remaining 4 lesions had no significant changes in size. ③ The average sizes of 14 lesions in 11 patients at 5-7 months after implantation were obviously smaller than those before implantation (1.84 cm vs 3.41 cm, t =5.7237, P ＜ 0.001). The average sizes of 12 lesions in 10 patients at 8-10 months after implantation were also obviously smaller than those before implantation (1.96 cm vs 3.43 cm, t =5.577 8, P ＜ 0.002).CONCLUSION: CT-guided 125I implantation is a safe, effective and feasible method for the treatment of malignant tumor.