D'Amico A, Cormack R, Kumar S, Tempany C M
Joint Center for Radiation Therapy, Harvard Medical School, Boston, Massachusetts 02215, USA.
J Endourol. 2000 May;14(4):367-70. doi: 10.1089/end.2000.14.367.
A real-time three-dimensional magnetic resonance imaging (MRI)-guided implant technique has been designed and implemented. This report summarizes the dosimetry achieved and the acute morbidity in the first patients.
To date, 43 patients with clinical stage T(1c)N(X)M(0) prostate cancer, serum prostate specific antigen <10 ng/mL, and biopsy Gleason score no higher than 3 + 4 have been treated. The procedure was performed using an open magnet, with axial T1-weighted and fast spin echo images. The prescribed minimum radiation dose to the peripheral zone was 160 Gy. The total activity implanted ranged from 18.8 to 47.5 mCi using 43 to 120 (median 80) (125)I seeds. Dosimetric analyses were performed intraoperatively in real time for the tumor, anterior rectal wall, and prostatic urethra.
The percent of the clinical target volume receiving the prescription dose was 89% to 99% (median 96%). Using a conservative estimate of 164 Gy, no more than 9% of the urethral volume exceeded the tolerated dose. Using an estimated tolerated dose of 82 Gy, 30% to 100% (median 68%) of the anterior rectal wall volume was within the dose limit. Thirty-nine patients voided spontaneously within 3 hours of Foley catheter discontinuation, although four patients required recatheterization for a period. No patient reported gastrointestinal or sexual dysfunction during the first postoperative month.
A real-time MR-guided technique can achieve a minimum of 89% coverage of the tumor volume while maintaining the prostatic urethra and most of the anterior rectal wall below tolerance levels. Acute morbidity was minimal. Further follow-up is needed to ascertain the impact on cancer control and quality of life.
已设计并实施了一种实时三维磁共振成像（MRI）引导的植入技术。本报告总结了首批患者所实现的剂量测定结果及急性发病率。
迄今为止，已对43例临床分期为T(1c)N(X)M(0)的前列腺癌患者进行了治疗，这些患者血清前列腺特异性抗原<10 ng/mL，活检Gleason评分不高于3 + 4。手术使用开放式磁体，采用轴向T1加权和快速自旋回波图像。外周区规定的最小辐射剂量为160 Gy。使用43至120（中位数80）颗（125）碘籽源，植入的总活度范围为18.8至47.5 mCi。术中对肿瘤、直肠前壁和前列腺尿道进行实时剂量分析。
接受处方剂量的临床靶体积百分比为89%至99%（中位数96%）。采用164 Gy的保守估计，不超过9%的尿道体积超过耐受剂量。采用估计耐受剂量82 Gy，30%至100%（中位数68%）的直肠前壁体积在剂量限值内。39例患者在拔除 Foley 导管后3小时内自行排尿，尽管有4例患者需要再次插管一段时间。术后第一个月内无患者报告胃肠道或性功能障碍。
实时MR引导技术可实现至少89%的肿瘤体积覆盖，同时将前列腺尿道和大部分直肠前壁维持在耐受水平以下。急性发病率极低。需要进一步随访以确定对癌症控制和生活质量的影响。
