ABSTRACT
External beam radiation therapy (EBRT) is one of the main treatments for prostate cancer, and image-guided implementation of EBRT is more suitable for accurate radiotherapy. As a new type of image-guided technology, the Clarity system has been applied in the real-time tracking during EBRT for prostate cancer in clinical practice. While improving the accuracy of EBRT targeting, it also significantly reduces the side effects of traditional EBRT. In this article, the application of Clarity system in EBRT of prostate cancer and its existing problems were systematically elucidated.
ABSTRACT
Objective:To compare the dosimetric difference between IMRT and VMAT plans for ovarian protection after cervical cancer ovarian transposition surgery.Methods:Thirty-one patients who had received both cervical cancer resection and ovarian transposition were selected for adjuvant radiotherapy. The 9-field evenly divided IMRT and the dual-arc VMAT technology were performed for the treatment planning. The difference of the ovarian mean dose between the two techniques was explored. The relationship between the position of the ovarian-target interval and the ovarian dose was also analyzed.Results:A total of 54 ovaries in 31 patients were effectively transposed and moved out of the target area. Among them, 9 ovaries were located above the upper boundary of the PTV. For these cases, the ovarian mean dose of IMRT and VMAT were (177.8±90.7) and (166.7±70.6) cGy, respectively, which was not statistically different( P>0.05).45 ovaries were located in the same level with PTV. For these cases, the ovarian mean dose of IMRT and VMAT were (459.1±239.9) and (428.3±238.2) cGy, respectively ( z=3.11, P=0.002). The ovarian mean dose has the highest correlation and negative correlation with the closest lateral distance from the ovarian volume center to the PTV surface (IMRT, r=-0.922, P=0.001; VMAT, r=-0.865, P=0.001). To reduce the ovarian mean dose to 500 cGy, the lateral closest distance between the ovarian volume center and the PTV surface should be 3.6 cm and 3.3 cm for IMRT and VMAT respectively. Conclusions:There is no difference between the two planned ovarian doses when the ovaries were located above the upper boundary of the PTV. When the ovaries were located in the same level with PTV, the VMAT plan is better than IMRT in both ovarian dose and treatment efficiency. The ovarian dose could be predicted by the lateral closest distance from the ovarian volume center to the PTV.
ABSTRACT
Objective To evaluate the short- and long-term efficacy of microwave hyperthermia combined with chemoradiotherapy in treating metastatic nasopharyngeal carcinoma to the cervical lymph nodes. Methods A total of 154 cases of stage N2-N3 nasopharyngeal carcinoma (1992 stage system) were randomized into two groups: group A (76 cases, treated with microwave hyperthermia combined with chemoradiotherapy) and group B (78 ca-ses, treated with chemoradiotherapy alone). Both groups received 1 to 2 cycles of chemotherappy with cisplatin and 5-fluorouracil and then received regular radiotherapy. The total doses of radiotherapy were 70-78 Gy/35-39 f, 47-51 d for the primary loci of nasopharynx and 68-72 Gy/34-36 f,46-50 d for the metastatic loci in the neck. Group A received microwave hyperthermia on the metastatic cervical node at the beginning of radiotherapy, with the micro-wave hyperthermia administered for 45 min every time,two times a week, totaling 8 to 14 times. Results The complete extinction rates of neck metastatic carcinoma were 80.3% and 61.5% , respectively, in groups A and B (P<0.05). The overall response rates of neck metastasis in the two groups were 100% and 96.2% , respective-ly. When the cervical lymph node metastasis disappeared, the radiotherapy doses in group A and B were (45.8 ± 5.46 ) Gy and (58.8±5.03 ) Gy, respectively (P<0.01). The 5-year local control rates of cervical lymph node in group A and B were 97.4% and 76.9%(P<0.05 ), respectively. The one-, three- and five- year survival rates were 97.4% , 76.3% and 59.2% respectively, in group A, versus 93.6% (P>0.05) ; and 52.6% (P< 0.01) and 41.0% (P<0.05), respectively, in group B. Conclusions Microwave hyperthermia combined with chemoradiotherapy can elevate the complete extinction rate of cervical lymph node metastasis of nasopharyngeal carcinoma and reduce the radiotherapy dose needed of effective control. The 5-year local control rate of cervical lymph node metastasis in combined therapy group is superior to that in the chemoradiotherapy alone group,and can elevate the long-term survival rate of patients.