Farrell T J, Wilson B C, Patterson M S, Olivo M C
Hamilton Regional Cancer Centre, Department of Medical Physics, Hamilton Regional Cancer Centre, ON, Canada.
Photochem Photobiol. 1998 Sep;68(3):394-9.
The photodynamic threshold dose in normal rat liver was determined from the measured depth of necrosis following surface irradiation. The threshold was determined for the photosensitizing drugs Photofrin and monosulfonated aluminum chlorophthalocyanine, AlPcS1, at 24 h postinjection and was found to be (3.4 x/divided by 1.3) x 10(18) and (8.2 x/divided by 1.5) x 10(18) photons cm-3, respectively, compared with the previously reported value of (38 +/- 2) x 10(18) photons cm-3 for the tri/tetrasulfonated phthalocyanine, AlPcS4. These values were independent of drug concentration or total light fluence. For all three drugs the depth of tissue necrosis decreased as the time between drug and light administration increased from 10 min to 72 h. This decrease can be attributed both to the change in the tissue drug concentration as well as to changes in the efficiency of photodynamic therapy for producing tissue damage, related to the photodynamic necrosis threshold. The threshold values for all three photosensitizers were lowest at 10 min post injection: (1.4 x/divided by 1.4) x 10(18), (1.6 x/divided by 1.3) x 10(18) and (23 x/divided by 1.3) x 10(18) photons cm-3 for Photofrin, AlPcS1 and AlPcS4, respectively. The changes in necrosis threshold with time may be due to an initial change from entirely vascular to a combination of vascular and cellular damage, with later redistribution of the photosensitizer to targets at the subcellular level.
通过测量表面照射后正常大鼠肝脏坏死深度来确定光动力阈值剂量。在注射光敏药物卟啉钠和单磺酸铝酞菁（AlPcS1）后24小时测定阈值，发现分别为(3.4÷1.3)×10¹⁸和(8.2÷1.5)×10¹⁸光子·厘米⁻³，而之前报道的三/四磺酸酞菁（AlPcS4）的值为(38±2)×10¹⁸光子·厘米⁻³。这些值与药物浓度或总光通量无关。对于所有三种药物，随着给药与光照之间的时间从10分钟增加到72小时，组织坏死深度均降低。这种降低既归因于组织药物浓度的变化，也归因于与光动力坏死阈值相关的光动力疗法产生组织损伤效率的变化。所有三种光敏剂的阈值在注射后10分钟时最低：卟啉钠、AlPcS1和AlPcS4分别为(1.4÷1.4)×10¹⁸、(1.6÷1.3)×10¹⁸和(23÷1.3)×10¹⁸光子·厘米⁻³。坏死阈值随时间的变化可能是由于最初从完全的血管损伤转变为血管和细胞损伤的组合，随后光敏剂重新分布到亚细胞水平的靶点。
