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KMID : 1164220050170010001
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Journal of Korean Society for Radiotherapeutic Technology
2005 Volume.17 No. 1 p.1 ~ p.8
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Packing effects on the intracavitary radiation Therapy 3-Dimension plan of the uterine cervix cancer
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Si Chang-Keun
Cho Jung-Keun
Lee Doo-Hyeon
Kim Sun-Young
Kim Tae-Yoon
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Abstract
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Purpose : An effect of a packing to uterine treatment of a cervical cancer using a dose-volume histogram for a point dose and a volume dose of the bladder and the rectum was analyzed by establishing a three-dimensional treatment plan using a CT image.
Materials and methods : Reference points of the bladder and the rectum were marked, respectively at a treatment plan device (plato brachytherapy V14.2.4) by photographing CT(marconi, USA) when the packing was used and removed under the same condition and a treatment plan was performed to Apoint depending on ICRU38. However, in case of the rectum, a maximum point was looked up and compared with the above point because the point presented from the ICRU is not proper as a representative value of a rectum point dose. Further, the volume dose depending on volume of point doses of the rectum and the bladder was measured. The measured values were used to analyze the effect of the packing through a Wilcoxon Signed Rank Test (a SAS statistical analysis process program).
Result : The reference points at the bladder and rectum doses when the packing was removed were and , respectively. The points when the packing was used were and , respectively. After the packing was used, the reference points at the bladder and the rectum were decreased by and , respectively. When the packing was removed, the maximum points at the bladder and the rectum were , respectively. When the packing was used, the maximum points at the bladder and the rectum were , respectively. After the packing was used, the maximum points at the bladder and the rectum were decreased by and , respectively. When the packing was removed, the bladder volume at point doses of the rectum and the bladder were , respectively and its rectum volume were , respectively. When the packing was used, the bladder volume at point doses of the rectum and the bladder were , respectively and its rectum volume were , respectively. After the packing was used, the bladder volume at point doses of the rectum and the bladder were decreased by , respectively and its bladder volume were decreased by , respectively.
Conclusion : Values at Reference point doses of the bladder and the rectum recommended from the ICRU 38 were 0.0781 and 0.0781, respectively and values of their maximum point doses were 0.0156 and 0.0156, respectively, as a result of which an effect of the packing using at the uterine intracavitary treatment of an uterine cervical cancer through the three-dimensional treatment plan used CT were measured. That is, the values at reference point doses and the values at maximum point doses show similar difference. However, P value was 0.15 at over volume doses and the value shows no similar difference. In other words, the effect of the packing looks like having a difference at the point dose, but actually shows no difference at the volume dose. The reason is that the volume of the bladder and the rectum are wide but the volume of the packing is only a portion. Therefore, the effect of decreasing the point dose was not great. Further, the farer the distance is, the more weak the intensity of radiation is because the intensity of radiation is proportional to inverse square of a distance. Therefore, the effort to minimize an obstacle of the bladder and the rectum by using the packing should be made.
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KEYWORD
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intracavitary, point dose, volume dose, packing effect
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