Thiel H J, Müller R, Schrott K M
Strahlenther Onkol. 1987 Mar;163(3):176-84.
Severe complications (urethral stricture, ulcer at the anterior rectum wall, prostato-rectal fistula) have been observed in 28%(5/18) of patients treated by combined percutaneous and interstitial therapy for locally confined prostatic cancer. These complications were caused above all by charging the big prostatic volumes with an excessive number of iodine-125 seeds applied through cannulas arranged too closely and by an insufficient distance between the mucous membrane of the rectum and the first seed. The evaluation of our data showed insignificant complications up to a total activity of 28 mCi, slight or medium complications between 28 and 35 mCi, and severe complications between 35 and 40 mCi. It is therefore necessary in case of an intended combination of interstitial and percutaneous irradiation to take precautionary measures already during the implantation in order to avoid critical accumulated doses: the spatial distribution of the seeds may be not so close and the total activity has to be lower (25 to 30 mCi). The MPD (minimal peripheral dose) can be by 30 to 40% below that of implantation alone and the dose in the centre of the implant should not exceed the MPD value by more than 100%. If a considerable volume (greater than 10 cm3) is irradiated by the implant with more than 240 Gy, the percutaneous boost generally performed up to 40 Gy has to be reduced, or the centre of the implant must be shielded by lead satellites after 20 Gy at the latest. The distance between the seeds and the mucous membrane of the rectum should be at least 1 cm, the interval between interstitial and percutaneous irradiation at least 8, better 12 weeks. A percutaneous boost is only performed in case of a very inhomogeneous interstitial dose distribution and a too low MPD (in form of a rotating irradiation up to 30 Gy: 16 Gy by open radiation and 14 Gy with H absorber) or in case of microscopic manifestations in the pelvic lymph nodes or suspected beginning manifestations in the seminal vesicles (in form of a four field irradiation up to 50 Gy using individual secondary collimators in order to shield sound tissues as well as the prostate which is already sufficiently irradiated by the seeds.
在采用经皮和组织间联合治疗局限性前列腺癌的患者中，28%（5/18）出现了严重并发症（尿道狭窄、直肠前壁溃疡、前列腺直肠瘘）。这些并发症主要是由于通过排列过密的套管植入过多的碘-125粒子，导致前列腺体积较大，以及直肠黏膜与第一枚粒子之间距离不足所致。对我们的数据评估显示，总活度达28 mCi时并发症不显著，28至35 mCi之间出现轻度或中度并发症，35至40 mCi之间出现严重并发症。因此，在打算进行组织间和经皮照射联合治疗时，植入过程中就必须采取预防措施，以避免关键累积剂量：粒子的空间分布不能过密，总活度必须更低（25至30 mCi）。最小外周剂量（MPD）可比单纯植入低30%至40%，植入中心的剂量不应超过MPD值100%以上。如果植入物照射体积较大（大于10 cm³）且剂量超过240 Gy，通常进行的40 Gy经皮增量照射必须减少，或者最迟在20 Gy后用铅质卫星屏蔽植入中心。粒子与直肠黏膜之间的距离应至少为1 cm，组织间照射与经皮照射之间的间隔至少为8周，最好为12周。仅在组织间剂量分布非常不均匀且MPD过低（采用旋转照射达30 Gy：开放辐射16 Gy和H吸收器14 Gy）时，或盆腔淋巴结有微观表现或精囊有可疑早期表现时（采用四野照射达50 Gy，使用单独的二级准直器以屏蔽正常组织以及已被粒子充分照射的前列腺），才进行经皮增量照射。
