The use of tissue fiducial markers in improving the accuracy of post-prostatectomy radiotherapy
- Author:
Michael CHAO
1
;
Huong HO
;
Daryl Lim JOON
;
Yee CHAN
;
Sandra SPENCER
;
Michael NG
;
Jason WASIAK
;
Nathan LAWRENTSCHUK
;
Kevin MCMILLAN
;
Shomik SENGUPTA
;
Alwin TAN
;
George KOUFOGIANNIS
;
Margaret COKELEK
;
Farshad FOROUDI
;
Tristan Scott KHONG
;
Damien BOLTON
Author Information
- Publication Type:Original Article
- Keywords: Fiducial marker; Image-guided radiotherapy; Intensity-modulated radiotherapy; Prostatectomy; Prostate cancer
- MeSH: Clothing; Cone-Beam Computed Tomography; Fiducial Markers; Humans; New Zealand; Postoperative Complications; Prostate; Prostatectomy; Prostatic Neoplasms; Radiation Oncology; Radiotherapy; Radiotherapy, Image-Guided; Radiotherapy, Intensity-Modulated; Rectum; Retrospective Studies; Urinary Bladder
- From:Radiation Oncology Journal 2019;37(1):43-50
- CountryRepublic of Korea
- Language:English
- Abstract: PURPOSE: The aim of this retrospective study was to investigate the use of a radiopaque tissue fiducial marker (TFM) in the treatment of prostate cancer patients who undergo post-prostatectomy radiotherapy (PPRT). TFM safety, its role and benefit in quantifying the set-up uncertainties in patients undergoing PPRT image-guided radiotherapy were assessed. MATERIALS AND METHODS: A total of 45 consecutive PPRT patients underwent transperineal implantation of TFM at the level of vesicourethral anastomosis in the retrovesical tissue prior to intensity-modulated radiotherapy. Prostate bed motion was calculated by measuring the position of the TFM relative to the pelvic bony anatomy on daily cone-beam computed tomography. The stability and visibility of the TFM were assessed in the initial 10 patients. RESULTS: No postoperative complications were recorded. A total of 3,500 images were analysed. The calculated prostate bed motion for bony landmark matching relative to TFM were 2.25 mm in the left-right, 5.89 mm in the superior-inferior, and 6.59 mm in the anterior-posterior directions. A significant 36% reduction in the mean volume of rectum receiving 70 Gy (rV₇₀) was achieved for a uniform planning target volume (PTV) margin of 7 mm compared with the Australian and New Zealand Faculty of Radiation Oncology Genito-Urinary Group recommended PTV margin of 10 mm. CONCLUSION: The use of TFM was safe and can potentially eliminate set-up errors associated with bony landmark matching, thereby allowing for tighter PTV margins and a consequent favourable reduction in dose delivered to the bladder and rectum, with potential improvements in toxicities.
