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Abstract：
Assess the interfraction dose variations of the organs at risk (OARs) in carcinoma cervix high dose rate (HDR) computed tomography (CT)-guided intra cavitary brachytherapy (ICBT). 120 CT scans of 40 patients who had undergone three fractions of ICBT (7 Gy/fr) were analyzed. Dose to Point A and the minimum doses to the volumes of 2, 1, and 0.1cc of bladder, rectum and sigmoid colon were recorded. Revised plans were generated in 20 patients. Paired t-test was used to compare the difference in the means. Point \"A\" mean dose difference was statistically significant between the treated and revised plans. For bladder, the difference in means of dosage to all volumes, whilst for the rectum and sigmoid colon, the low volume dosage (0.1cc) was statistically significant. Absence of individualized planning would have resulted in underdosage of tumor and increased dosage of up to 30% to OARs. CT-guided ICBT should be implemented for each HDR fraction treatment.
摘要：
评估宫颈癌高剂量率（HDR）计算机断层扫描（CT）引导的腔内近距离放射治疗（ICBT）中危险器官（OAR）的剂量变化。分析了40例经历了三次ICBT（7Gy/fr）的患者的120次CT扫描。A点的剂量和2、1和0.1cc膀胱体积的最小剂量，记录直肠和乙状结肠。20例患者制定了修订计划。使用配对t检验来比较平均值的差异。“A”点平均剂量差异在治疗计划和修订计划之间具有统计学意义。对于膀胱，剂量与所有体积的差异，而对于直肠和乙状结肠，低体积剂量(0.1cc)有统计学意义。缺乏个性化计划会导致肿瘤的剂量不足，而OAR的剂量增加高达30％。CT引导的ICBT应该对每个HDR部分治疗实施。
