Olsen D R, Lyng H, Petersen S, Rofstad E K
Department of Medical Physics, Norwegian Radium Hospital, Oslo.
Acta Oncol. 1995;34(3):339-43. doi: 10.3109/02841869509093986.
Previous 31P-magnetic resonance spectroscopy (31P-MRS) studies have suggested that the spin-lattice relaxation time (T1) of the inorganic phosphate (Pi) resonance is shorter in well-oxygenated than in poorly oxygenated tumors. Amelanotic human melanoma xenografts were therefore subjected to 31P-MRS to investigate whether the T1 of the Pi resonance might be a useful parameter for assessment of tumor oxygenation status. It was searched for possible correlations between the T1 of the Pi resonance and oxygen tension or parameters closely related to oxygen tension, including 31P-MRS tumor energy status and blood supply per viable tumor cell. Oxygen tension, tumor energy status, and blood supply per viable tumor cell decreased with increasing tumor volume. In contrast to previous suggestions, the T1 of the Pi resonance decreased with increasing tumor volume and decreasing oxygen tension, tumor energy status, and blood supply per viable tumor cell, possibly because the tumors developed necrotic regions concomitantly with the decrease in oxygenation status, resulting in increased concentrations of freely dissolved para-magnetic ions in the tissue. Consequently, the T1 of the Pi resonance can probably not be utilized to estimate the oxygenation status of tumors, at least not in tumors with necrotic regions.
以往的31P磁共振波谱（31P-MRS）研究表明，无机磷酸盐（Pi）共振的自旋晶格弛豫时间（T1）在氧合良好的肿瘤中比在氧合不良的肿瘤中更短。因此，对无黑色素的人黑色素瘤异种移植瘤进行了31P-MRS研究，以探讨Pi共振的T1是否可能是评估肿瘤氧合状态的有用参数。研究了Pi共振的T1与氧张力或与氧张力密切相关的参数之间的可能相关性，包括31P-MRS肿瘤能量状态和每个存活肿瘤细胞的血液供应。随着肿瘤体积的增加，氧张力、肿瘤能量状态和每个存活肿瘤细胞的血液供应减少。与先前的观点相反，Pi共振的T1随着肿瘤体积的增加以及氧张力、肿瘤能量状态和每个存活肿瘤细胞的血液供应的减少而降低，这可能是因为肿瘤在氧合状态降低的同时出现了坏死区域，导致组织中自由溶解的顺磁性离子浓度增加。因此，Pi共振的T1可能无法用于估计肿瘤的氧合状态，至少在有坏死区域的肿瘤中不行。
