Morphological changes after Nd:YAG laser treatment of the human prostate with the SideFocus fiber: correlation to MRI and impact of dosimetry and time

摘要

Determination of optimal treatment parameters and appropriate methods of examination for Nd:YAG laser coagulation of the human prostate in dependence of power-setting and time using the SideFocus$+R$/ side-firing delivery system. Transurethral free-beam laser coagulation was performed in 10 patients prior to planned radical prostatectomy. Thereof 6 underwent laparoscopic lymphadenectomy and laser coagulation of the prostate between 4 and 9 days prior to open surgery. These same patients had undergone MRI-examination with an endorectal coil during staging and prior to radical prostatectomy. Depth and volume of coagulated prostatic tissue of a 4-quadrant laser application were measured at power settings of 40 W/90 s and 60 W/60 s. There was no difference in volume coagulation between the two treatment modalities. In contrast there was a significant difference in volume coagulation between those prostates removed at 4 to 9 days and those removed t 60 to 210 minutes after laser coagulation. In histological and MRI- examination, however, there was a strong correlation with view to coagulation volume. Both treatment modalities showed comparable volume coagulation with laser induced changes conclusively discernible by 4 days. MRI-examination with an endorectal coil proved to be perfectly suitable for assessment.