Hamamoto Yasushi, Inata Hiroki, Sodeoka Noritaka, Nakayama Shigeki, Tsuruoka Shintaro, Takeda Hideki, Manabe Toshiharu, Mochizuki Teruhito, Umeda Masakichi
Department of Radiology, Saiseikai-Imabari Hospital, 7-1-6 Kitamura, Imabari, Ehime, 799-1592, Japan,
Jpn J Radiol. 2015 Apr;33(4):187-93. doi: 10.1007/s11604-015-0396-3. Epub 2015 Feb 8.
Intrafraction prostate displacement (IFPD) through the course of conventionally fractionated radiotherapy was observed by real-time tracking.
IFPD was observed by using a CyberKnife real-time tracking system over 39 serial fractions in two patients. Stereoscopic X-ray images tracking the implanted fiducial markers were obtained with mean intervals of 58 s. In preparation for treatment, urination was performed routinely 1 h before treatment and rectal gas was evacuated if necessary. Patients were immobilized by a thermoplastic body shell.
The maximal absolute values of IFPD in all 78 fractions were 7.9, 2.1, and 11.5 mm in cranio-caudal (CC), left-right (LR), and antero-posterior (AP) direction, respectively. Only in 5 % of fractions (4/78 fractions), the maximal absolute values of IFPD were 5.0 mm or larger. In these fractions, large IFPD was temporary or persistent. IFPD of ≥3 mm was detected in only ~2-3 % of all obtained tracking images.
Daily maximal IFPD changed day by day. Although maximal IFPD was more than 10 mm, IFPD of ≥3 mm was observed in a comparatively small proportion of treatment time. Through the course of conventionally fractionated radiotherapy, fractions with IFPD of ≥5 mm were infrequent.
通过实时跟踪观察常规分割放疗过程中的分次内前列腺位移（IFPD）。
使用射波刀实时跟踪系统对两名患者的39次连续分次放疗过程中的IFPD进行观察。以平均58秒的间隔获取跟踪植入基准标记的立体X射线图像。在治疗准备阶段，治疗前1小时常规排尿，必要时排出直肠气体。患者通过热塑性体模固定。
在所有78次分次放疗中，IFPD在头脚（CC）、左右（LR）和前后（AP）方向的最大绝对值分别为7.9、2.1和11.5毫米。仅在5%的分次放疗（4/78次）中，IFPD的最大绝对值为5.0毫米或更大。在这些分次放疗中，较大的IFPD是暂时的或持续的。在所有获取的跟踪图像中，仅约2 - 3%检测到IFPD≥3毫米。
每日最大IFPD逐日变化。尽管最大IFPD超过10毫米，但在相对较小比例的治疗时间内观察到IFPD≥3毫米。在常规分割放疗过程中，IFPD≥5毫米的分次放疗很少见。
