| objective:To observe the repeated CT scan in patients with cervical cancer throughout a course of intensity modulated radiation therapy (IMRT) in intra-and inter-fractionated irradiation during the movement of the uterus to guide choice of target boundaries in IMRT of local progress cervical cancer.And research the effect of breath to the movement.Method:1,8 in the initial treatment of local advanced cervical cancer patients before treatment and then weekly during external beam radiotherapy respectively performance a enhanced positioning pelvic CT scan. The first, the third (ie, after irradiation 20GY) and the fifth(ie, after irradiation 40GY) repeated scan the same range once every 5 minutes,to complete a total of 4 CTs in 15 minutes, including a four-dimensional CT scans.2, respectively,15 minutes 4 CT images and every week enhanced CT images fusion. Use planning software in 15 minutes CT fusion image define the points of interest:point U (most superior-anterior aspect of the uterine fundus, lying on a line passing along the central axis of the uterine body uterus); point C:(the postero-inferior aspect of the cervix along the cervical central axis). To analyse the intra fraction movement of uterus in lateral,vertical and anterior/posterior(AP) directions.Analyse end-expiratory and end-inspiratory mobility changes in the same way.3, On 5 times weekly enhanced CTs fusion image determined the point of interest U for the analysis of the movement of the uterus body, and outlined cervical tumor on each CT image to Analyse the movement of the geometric center in each direction.4, SPSS 13.0 software for statistical analysis. Results:A total of 96 CT image data to be used for a single exposure of a moving analysis,40 CT image data is used to move several times during the segmentation analysis,8 four-dimensional CT image data is used to quiet breathing mobility Analysis.1,15 minute single durations of irradiation, cervix in lateral,vertical,AP direction average displacement respectively is 1.4mm(SD±1.1mm),1.6mm (SD±1.4mm),1.7mm (SD±1.2mm); Biggest movement respectively is 4.6mm,5.1mm,5.7mm.15 minute scanning period, body in lateral,vertical, AP direction average displacement respectively be 1.8mm(SD±1.4mm),2.0mm (SD±1.7mm),2.0mm (SD±1.5mm); The biggest movement is 5.0mm,8.3mm,6.6mm.2nd,The CT data analysis once a week demonstrated that cervix in lateral,vertical, AP direction average displacement respectively be 3.9mm(SD±3.8mm),3.8mm (SD±4.0mm),7.9mm (SD±6.8mm); The biggest movement respectively be 12.7mm,16.1mm,24.0mm. The uterus body in lateral,vertical, AP direction average displacement respectively is 6.5mm (SD±4.8mm),9.5mm (SD±6.6mm), 14.2mm (SD±10.5mm); The biggest movement respectively is 15.6mm,25.8mm, 36.4mm.3rd, in a respiratory cycle the inspiration end and the expiration end cervix and body’s displacement change does not surpass 0.8mm at the various directions biggest displacement.4th, after radiotherapy second week, third week, fourth week, the fifth week (i.e. radiotherapy 10GY,20GY,30GY,40GY), separately before the radiotherapy quite obtained cervix,the body of uterus moving data and radiotherapy period during every two weeks the moving data making T-test demonstrated that the cervical rumor and the uterus body motion have the remarkable difference in the AP direction, during every two weeks moving reduces obviously:The body reduces 7.5±7.6mm, the cervix reduces 4.0±4.1mm. The motion in other direction does not have the difference (a=0.05). Conclusion:the division the uterus and the tumor motion are very big during inter-fraction, which is two to seven times to the situation of intra-fraction, regardless inter-or intra-fraction body moving to compare the cervix be bigger. In intra-fraction gives 4mm in various directions surrounding the cervix and 5mm in various directions to encompass the body of uterus satisfies 95% situations sufficiently. To satisfy 95% situation in inter-fraction cervix lateral direction approximately to need 9mm, vertical direction approximately needs 10mm, AP direction needs 19mm; About the uterus body, respectively needs 14mm,20mm,32mm. If treatment period carries on once a week the three dimensional image registration, the AP direction of cervix may reduce to 11mm, uterus body 20mm. Therefore suggest treatment organizations which lack of the daily soft tissue image registration and the adaptive radiotherapy to carry on the three dimensional image soft tissue registration once a week during IMRT of cervical cancer. The tranquil breath is very small to the uterus moving influence may ignore, but the deep breathing possibly has affects greatly. Second part:The research of uterus four-dimensional motion during IMRT combined 3D intracavity therapy to treat cervical cancerbjective:Objective:to study the cervical cancer without surgery for patients after placing applicator the four-dimensional movement of uterus, which to guide target margin choice in the new technology——IMRT fusion 3D intracavity therapy to treat cervical cancer. Understanding breath to the influence of dynamic degrees.Methods:1, after 8 without surgery cervical cancer patients external irradiation treatment had ended, posts applicator and then scans located CT.Every other 4-5 minutes carry on one time the interest area CT scanning, in 20 minutes completes including four-dimensional CT altogether 5 CTs.2, in the cervix and the uterus body identified two points of interest (point U:most superior-anterior aspect of the uterine fundus, lying on a line passing along the central axis of the uterine body uterus; point C:the postero-inferior aspect of the cervix along the cervical central axis), The difference in position between the two corresponding points on the scans was measured in the superior-inferior (SI), antero-posterior (AP) and lateral directions.3, selected in each patient four-dimensional CT the inspiration end and the expiration end two phase CT images, with on law computation the points of interest various directions displacement value.4, surveys in each patient 5 CTs uterine cavity applicator the relative uterus in 3D directions position variation.5, Took the SPSS 13.0 software to carry on statistics analysis.Results:Altogether 40 CTs and 8 four-dimensional CTs data used in analyzing. 1,20 minute durations of irradiation, cervix in lateral, AP, SI directions average displacement respectively was 0.90 mm (SD±0.55mm),1.15mm (SD±0.75mm), 0.60mm (SD±0.65mm); Biggest movement scope lateral direction was 1.97mm, AP,2.66mm (when deep breathing reaches 4.44mm), SI,2.26mm.20 minute durations of irradiation, uterine body in lateral,AP,SI direction average displacement respectively was 0.93 mm (SD±0.68mm),1.17mm (SD±0.86mm), 1.31mm (SD±0.70mm); Biggest movement scope lateral direction was 2.65mm, AP,2.80mm (when deep breathing reaches 5.89mm), IS,2.40mm.2, in a tranquil respiratory cycle the inspiration end and the expiration end cervix and uterine body’s displacement changes not obviously, biggest displacement only 0.5mm. But the deep breathing obviously affects uterus in AP direction movement, the uterine body reaches 5.89mm, the cervix reaches 4.44mm.3,20 minute durations of irradiation, applicator relative uterus in every direction had not had the relative displacement. Conclusion:1, when IMRT fusion three dimensional afterloading intracavity therapy to treat cervical cancer, because has posted applicator such rigid material, in the single radiotherapy time the cervix, the uterine body moves very small:The cervix and the body in every direction moves less than 3mm. So uterus various directions put 3mm may take applies this technology treat margin as reference.2, the tranquil breath to the cervix and the uterine body movement has not have obvious influence. But when deep breathing has obvious influence to AP direction moving.3, duration of irradiation, although the womb has slight movement, but between applicator and the uterus has not had the relative displacement, therefore does not affect in target area dosage from the three dimensional intracavity therapy plan. |
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