Kirschner Austin N, Sathiaseelan Vythialingam, Zhang Yunkai, David James, Kalapurakal John A
Radiation Oncology, Northwestern Memorial Hospital, Chicago, USA.
J Contemp Brachytherapy. 2014 Mar;6(1):33-9. doi: 10.5114/jcb.2014.42023. Epub 2014 Apr 3.
While there are several reports of prostate multisector dosimetry data obtained from CT or MRI scans performed at intervals ranging from 14-70 days after prostate brachytherapy (PB), there are no reports on multisector dosimetry performed in the immediate post-implant period. This study was undertaken to determine the results of prostate multisector dosimetry performed in the immediate post-implant period on day 1 post-implant dosimetry after (125)I PB.
The day 1 post-implant CT-based V100 and D90 were determined for the prostate base (PGB) and compared to doses to the entire gland (PG), mid-gland (PMG), and apex (PA) in 75 patients who underwent (125)I PB to a dose of 144 Gy. Similar multisector dosimetry was also performed on the pre-implant ultrasound volume study scans of these patients.
All patients had good quality implants. On day 1 post-implant multisector dosimetry there was significant under dosage of the PGB for both V100 and D90. The average magnitude of under dosage of PGB compared to PMG and PA was 17.2% and 22.7% for V100 and 44.6 Gy and 31.7 Gy for D90, respectively. On pre-implant multisector dosimetry there was no statistically significant under dosage of the PGB for V100, but the PGB D90 was significantly lower compared to PMG and PA, however, the average magnitude of under dosage was small at 12.6 Gy and 4.2 Gy, respectively.
This report demonstrates that similar to other reports on more delayed post-implant multisector dosimetry data, there is significant under dosage of the prostate base in the immediate post-implant period based on day 1 post-implant dosimetry. The clinical significance of this under dosage remains to be defined and further studies are warranted.
虽然有几份关于前列腺近距离放射治疗（PB）后14至70天期间进行的CT或MRI扫描获得的前列腺多区域剂量测定数据的报告，但尚无关于植入后即刻进行多区域剂量测定的报告。本研究旨在确定在（125）I前列腺近距离放射治疗后植入后第1天进行的前列腺多区域剂量测定的结果。
在75例接受（125）I前列腺近距离放射治疗且剂量为144 Gy的患者中，确定植入后第1天基于CT的前列腺底部（PGB）的V100和D90，并与整个腺体（PG）、腺体中部（PMG）和尖部（PA）的剂量进行比较。对这些患者植入前的超声容积研究扫描也进行了类似的多区域剂量测定。
所有患者植入质量良好。在植入后第1天的多区域剂量测定中，PGB的V100和D90均存在显著剂量不足。与PMG和PA相比，PGB的V100剂量不足的平均幅度分别为17.2%和22.7%，D90分别为44.6 Gy和31.7 Gy。在植入前的多区域剂量测定中，PGB的V100没有统计学上的显著剂量不足，但PGB的D90与PMG和PA相比显著较低，然而，剂量不足的平均幅度较小，分别为12.6 Gy和4.2 Gy。
本报告表明，与其他关于植入后更延迟的多区域剂量测定数据的报告类似，基于植入后第1天的剂量测定，植入后即刻前列腺底部存在显著剂量不足。这种剂量不足的临床意义仍有待确定，需要进一步研究。
