Helical tomotherapy-based total lymphoid irradiation: a more precise and less toxic radiation delivery system for consideration in composite tissue allotransplantation.
Helical tomotherapy-based total lymphoid irradiation: a more precise and less toxic radiation delivery system for consideration in composite tissue allotransplantation.
复制标题
基于螺旋断层放疗的全淋巴照射：一种更精确、毒性更小的放射输送系统，用于复合组织同种异体移植。
DOI：
10.1097/prs.0000000000001108
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发表时间：
2015
影响因子：
3.6
通讯作者：
Kaufman,DixonB
中科院分区：
文献类型：
--
作者：
Kempton,SteveJ;Robertson,FrederickA;Bentz,MichaelL;Kaufman,DixonB
通过骨髓或造血干细胞移植建立供受者混合造血嵌合体后，可以实现功能性同种异体移植耐受。全淋巴照射是骨髓移植前单克隆和多克隆抗体（化疗）预处理方案的一种可接受的辅助方法，可使供体细胞成功植入受体。这些疗法已导致实体器官移植患者持久的嵌合状态和完全的免疫抑制消除。[1]然而，由于担心对健康的“旁观者”组织的辐射损伤，复合组织同种异体移植的趋势是用化疗药物代替全淋巴照射。全淋巴照射的主要作用是抑制宿主免疫系统，这一作用与化疗药物耗竭相同。最近的研究已经发现了在化疗方案中加入全淋巴照射的额外益处。对淋巴和骨髓组织的辐照可为供体细胞植入创造短期局部小生境或“空间”，并增强辐照和非辐照组织中的全身植入。2在化疗药物消耗的基础上增加全淋巴照射，已显示出对移植物抗宿主病的保护作用，并促进T细胞重新增殖，倾向于调节免疫系统环境。3传统上，全淋巴照射是通过使用直线加速器和前后对置技术进行的。这需要改变患者定位和外部屏蔽，并且还使射束覆盖范围内的健康组织受到规定的辐射剂量。在过去的十年中，放射治疗技术已经朝着更精确的输送方法发展。图像调制放射治疗从多个角度使用多个低剂量辐射子束，以允许对肿瘤/靶体积进行精确的适形治疗，并在不伴随正常组织毒性增加的情况下逐步增加剂量。螺旋断层治疗代表了放射治疗的最新进展，并将图像调制放射治疗与现代兆伏计算机断层扫描图像引导相结合。增加的计算机断层扫描组件允许精确的预处理计划，重建输送的辐射剂量，和目标配准，以考虑内部运动和体积变化。重要的是，螺旋断层治疗允许适形避免（与适形治疗相对应），其专门针对并避免正常组织。多项肿瘤学研究表明，螺旋断层治疗显著降低
Functional allotransplant tolerance can be achieved following the establishment of mixed donor and recipient hematopoietic chimerism by way of bone marrow or hematopoietic stem cell transplantation. Total lymphoid irradiation is an accepted adjunct to monoclonal and polyclonal antibody (chemotherapeutic) conditioning regimens before bone marrow transplantation that allows for successful donor cell engraftment into the recipient. These therapies have led to durable chimerism and complete immunosuppression elimination in solid organ transplantation patients. 1 The tendency in composite tissue allotransplantation, however, has been to substitute chemotherapeutic agents for total lymphoid irradiation because of concern for radiation damage to healthy “bystander” tissues. The primary role of total lymphoid irradiation is to suppress the host immune system, a role that is shared with chemotherapeutic depletion. Recent studies have uncovered additional benefits of adding total lymphoid irradiation to chemotherapeutic regimens. Irradiation to lymphoid and bone marrow tissues may create a short-term local niche or “space” for donor cell engraftment, and enhance systemic engraftment in irradiated and nonirradiated tissues. 2 The addition of total lymphoid irradiation to chemotherapeutic depletion has been shown to provide a protective effect against development of graft-versus-host disease, and promote T-cell repopulation with a propensity toward a proregulatory immune system environment. 3 Traditionally, total lymphoid irradiation is administered through the use of a linear accelerator with an anteroposterior opposed technique. This requires changes in patient positioning and external shielding, and also subjects healthy tissues within the beam coverage to the prescribed radiation dose. In the past decade, radiation therapy technology has advanced toward more precise delivery methods. Image-modulated radiotherapy uses multiple low-dose radiation beamlets from multiple angles to allow for precise conformal therapy to tumor/target volumes and escalation of the dose without concomitant increase in normal tissue toxicity.Helical tomotherapy represents the most recent advance in radiation therapy and combines image-modulated radiotherapy with modern megavolt computed tomographic image guidance. The added computed tomographic component allows for precise pretreatment planning, reconstruction of delivered radiation dose, and target registration to account for internal motion and volume changes. Importantly, helical tomotherapy allows for conformal avoidance (counterpart to conformal therapy), which specifically targets and avoids normal tissues. Multiple oncologic studies have shown that helical tomotherapy significantly decreases