使用动态超极化（129）Xe磁共振波谱法检测大鼠辐射诱导的肺损伤。

Detection of radiation induced lung injury in rats using dynamic hyperpolarized (129)Xe magnetic resonance spectroscopy.

作者信息

Fox Matthew S, Ouriadov Alexei, Thind Kundan, Hegarty Elaine, Wong Eugene, Hope Andrew, Santyr Giles E

机构信息

Department of Physics and Astronomy, Western University, London, Ontario, N6A 3K7, Canada and Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, N6A 5B7, Canada.

Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, N6A 5B7, Canada.

出版信息

Med Phys. 2014 Jul;41(7):072302. doi: 10.1118/1.4881523.

DOI:10.1118/1.4881523

PMID:24989401

Abstract

PURPOSE

Radiation induced lung injury (RILI) is a common side effect for patients undergoing thoracic radiation therapy (RT). RILI can lead to temporary or permanent loss of lung function and in extreme cases, death. Combining functional lung imaging information with conventional radiation treatment plans may lead to more desirable treatment plans that reduce lung toxicity and improve the quality of life for lung cancer survivors. Magnetic Resonance Imaging of the lung following inhalation of hyperpolarized(129)Xe may provide a useful nonionizing approach for probing changes in lung function and structure associated with RILI before, during, or after RT (early and late time-points).

METHODS

In this study, dynamic(129)Xe MR spectroscopy was used to measure whole-lung gas transfer time constants for lung tissue and red blood cells (RBC), respectively (TTr_tissue and TTr_RBC) in groups of rats at two weeks and six weeks following 14 Gy whole-lung exposure to radiation from a (60)Co source. A separate group of six healthy age-matched rats served as a control group.

RESULTS

TTr_tissue values at two weeks post-irradiation (51.6 ± 6.8 ms) were found to be significantly elevated (p < 0.05) with respect to the healthy control group (37.2 ± 4.8 ms). TTr_RBC did not show any significant changes between groups. TTr_tissue was strongly correlated with TTr_RBC in the control group (r = 0.9601 p < 0.05) and uncorrelated in the irradiated groups. Measurements of arterial partial pressure of oxygen obtained by arterial blood sampling were found to be significantly decreased (p < 0.05) in the two-week group (54.2 ± 12.3 mm Hg) compared to those from a representative control group (85.0 ± 10.0 mm Hg). Histology of a separate group of similarly irradiated animals confirmed the presence of inflammation due to radiation exposure with alveolar wall thicknesses that were significantly different (p < 0.05). At six weeks post-irradiation, TTr_tissue returned to values (35.6 ± 9.6 ms) that were not significantly different from baseline.

CONCLUSIONS

Whole-lung tissue transfer time constants for(129)Xe (TTr_tissue) can be used to detect the early phase of RILI in a rat model involving 14 Gy thoracic (60)Co exposure as early as two weeks post-irradiation. This knowledge combined with more sophisticated models of gas exchange and imaging techniques, may allow functional lung avoidance radiation therapy planning to be achievable, providing more beneficial treatment plans and improved quality of life for recovering lung cancer patients.

摘要

目的

放射性肺损伤（RILI）是接受胸部放射治疗（RT）患者常见的副作用。RILI可导致肺功能暂时或永久性丧失，在极端情况下可导致死亡。将功能性肺成像信息与传统放射治疗计划相结合，可能会产生更理想的治疗计划，从而降低肺部毒性，提高肺癌幸存者的生活质量。吸入超极化（129）Xe后的肺部磁共振成像可能为探测RT前、RT期间或RT后（早期和晚期时间点）与RILI相关的肺功能和结构变化提供一种有用的非电离方法。

方法

在本研究中，动态（129）Xe磁共振波谱分别用于测量14 Gy全肺接受（60）Co源辐射后两周和六周的大鼠组中肺组织和红细胞（RBC）的全肺气转移时间常数（TTr_tissue和TTr_RBC）。另一组六只年龄匹配的健康大鼠作为对照组。

结果

发现照射后两周的TTr_tissue值（51.6±6.8毫秒）相对于健康对照组（37.2±4.8毫秒）显著升高（p<0.05）。TTr_RBC在各组之间未显示任何显著变化。对照组中TTr_tissue与TTr_RBC密切相关（r = 0.9601，p<0.05），而在照射组中不相关。通过动脉血采样获得的动脉血氧分压测量值在两周组（54.2±12.3毫米汞柱）中与代表性对照组（85.0±10.0毫米汞柱）相比显著降低（p<0.05）。另一组类似照射动物的组织学检查证实存在辐射暴露引起的炎症，肺泡壁厚度有显著差异（p<0.05）。照射后六周，TTr_tissue恢复到与基线无显著差异的值（35.6±9.6毫秒）。