Published online Dec 10, 2009.
https://doi.org/10.4068/cmj.2009.45.3.182
Application of Image-Guided Radiation Therapy (IGRT) with Gold Markers in Prostate Cancer
Abstract
For image-guided radiation therapy (IGRT) of prostate cancer, gold markers called fiducials can be inserted into the prostate in advance. Here we examined the short-term results of IGRT for prostate cancer. We obtained the clinical data of 10 patients who underwent IGRT at the Department of Radiation Oncology in Kangnam Sacred Heart Hospital of Hallym University during March 2006 and July 2007. Three gold markers were implanted in the prostate before the radiotherapy. Exact focusing of the image was obtained by 3 gold markers on simple X-ray film or cone beam computed tomography during radiation therapy. The errors induced by setting up the patients during IGRT were examined. The setup errors, averaged over all patients, were -0.88 mm, 1.85 mm, and -0.40 mm in the left-right, cranial-caudal, and anterior-posterior directions, respectively. The motion of the prostate was greatest in the cranial-caudal (6.5 mm) direction. The post-radiation therapy prostate-specific antigen (PSA) level was decreased dramatically in all 10 patients. Two of three patients who had received hormonal therapy with IGRT showed a PSA nadir 12 months later without hormonal therapy. There were no peri-radiotherapy complications. Through the use of IGRT with gold markers, we could correct the setup errors that occur in conventional radiation therapy. Post-IGRT PSA was decreased dramatically. Even though our data are limited, we suggest that IGRT may be an effective radiation therapy modality for decreasing peri-radiotherapy complications and improving radiotherapy results in prostate cancer through exact focusing of the radiation.
Fig. 1
Cliax iX with Cone-Beam CT.
Fig. 2
(A) Gold marker positions are Mkr1, Mkr2 and Mkr3 in the right base, left lateral and right apex of prostate. (B) Doctors may insert gold marker into the prostate by placing hollow gold needles through the rectum and moving a fiducial through each needle.
Fig. 3
Simple X-ray image showing three gold marker seeds.
Fig. 4
(A) The CT image showing significant displacement of simulation CT and cone-beam CT images. (B) Fused image was corrected with displacement vector components.
Fig. 5
Shifts along the principal directions of x-axis, y-axis and z-axis.
Table 1
Characteristics of the patients
Table 2
Relationship of the setup errors with prostate volume
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