Willoughby Twyla R, Kupelian Patrick A, Pouliot Jean, Shinohara Katsuto, Aubin Michelle, Roach Mack, Skrumeda Lisa L, Balter James M, Litzenberg Dale W, Hadley Scott W, Wei John T, Sandler Howard M
Department of Radiation Oncology, M.D. Anderson Cancer Center Orlando, Orlando, FL 32806, USA.
Int J Radiat Oncol Biol Phys. 2006 Jun 1;65(2):528-34. doi: 10.1016/j.ijrobp.2006.01.050.
The Calypso 4D Localization System is being developed to provide accurate, precise, objective, and continuous target localization during radiotherapy. This study involves the first human use of the system, to evaluate the localization accuracy of this technique compared with radiographic localization and to assess its ability to obtain real-time prostate-motion information.
Three transponders were implanted in each of 20 patients. Eleven eligible patients of the 20 patients participated in a study arm that compared radiographic triangulated transponder locations to electromagnetically recorded transponder locations. Transponders were tracked for 8-min periods.
The implantations were all successful, with no major complications. Intertransponder distances were largely stable. Comparison of the patient localization on the basis of transponder locations as per the Calypso system with the radiographic transponder localization showed an average (+/-SD) 3D difference of 1.5 +/- 0.9 mm. Upon tracking during 8 min, 2 of the 11 patients showed significant organ motion (>1 cm), with some motion lasting longer that 1 min.
Calypso transponders can be used as magnetic intraprostatic fiducials. Clinical evaluation of this novel 4D nonionizing electromagnetic localization system with transponders indicates a comparable localization accuracy to isocenter, (within 2 mm) compared with X-ray localization.
正在研发Calypso 4D定位系统，以便在放射治疗期间提供准确、精确、客观且连续的靶区定位。本研究首次对该系统进行人体应用，以评估该技术与放射成像定位相比的定位准确性，并评估其获取前列腺实时运动信息的能力。
20名患者每人植入3个应答器。20名患者中有11名符合条件的患者参与了一个研究组，该组将放射成像三角测量的应答器位置与电磁记录的应答器位置进行比较。应答器被跟踪8分钟。
植入均成功，无重大并发症。应答器之间的距离基本稳定。根据Calypso系统的应答器位置进行的患者定位与放射成像应答器定位的比较显示，三维平均（±标准差）差异为1.5±0.9毫米。在8分钟的跟踪过程中，11名患者中有2名显示出明显的器官运动（>1厘米），有些运动持续时间超过1分钟。
Calypso应答器可用作前列腺内磁性基准标记。对这种带有应答器的新型4D非电离电磁定位系统的临床评估表明，与X射线定位相比，其定位准确性与等中心相当（在2毫米以内）。
