An evaluation of GoldAnchor intraprostatic fiducial marker stability during the treatment planning Dawid Bodusz, Wojciech Leszczyński, Wioletta Miśta, Leszek Miszczyk Application of fiducial gold markers: prostate liver pancreas Lung Application of gold markers allowed the visualization of the position of the tumor on the X-ray images
tracking IGRT NAL Introduction 2D-2D kv, CB/CT Electronic Portal Image Device IGRT ExacTrac X-Ray X 6D IGRT Image guided radiation tehrapy SonArray- USG 3D MVCT Tomoterapia CyberKnife tracking
Purpose The aim of this study was to evaluate of fiducial marker migration inside the prostate during the planning of prostate cancer patients radiotherapy. Material and method: 30 prostate cancer patients radiotherapy technique: IMRT, RapidArc immobilisation system: thermoplastic mask Head First Supine Position (HFS) Dc=76 Gy/g; Df=2,0 Gy/g 2D/2D kv (OBI, Varian Medical Systems) additionally CBCT (OBI, Varian Medical Systems)
Material and method: 2mm length: mm diameter: 0.28mm Material and method: CBCT
Material and method: CBCT Acquisition (A) Full Fan: detector centered 30x40, reconstructed FOV of 24 cm in diameter, 15 cm in C- C extent. (B) Half Fan: detector shifted by 14.8 cm, FOV=45 cm diameter, 14 cm cm c-c extent Material and method: Bow-tie filters
Material and method: CBCT 3,5 44 42 3,0 2,5 2,0 1,5 40 38 36 34 32 30 28 26 24 1,0 0,5 22 18 Czas Średnia = 31,4583 Średnia±Błąd std = (29,1829, 33,7337) Średnia±Odch.std = (,3112, 42,6055) 0,0-0,5 SI LR AP 3D Mean Mean±SE Mean±SD
Średni a 4,5 4,0 3,5 3,5 3,0 3,0 2,5 2,0 2,5 1,5 1,0 SI 2,0 0,5 0,0 1,5-0,5 SI LR AP 3D Średni a±błąd std Średni a±odch.std 1,0 0,5 0,0 Σ = 1,2 mm σ = 0,9 mm -0,5-5 0 5 10 15 25 30 35 pomiar 2,2 2,0 1,8 1,6 3,5 3,0 2,5 1,4 1,2 2,0 1,5 1,0 LR 1,0 0,5 0,8 0,6 0,4 0,2 0,0 0,0-0,5 Średni a Średni a±błąd std Średni a±odch.std SI LR AP 3D Σ = 0,4 mm σ = 0,6 mm -0,2-5 0 5 10 15 25 30 35 pomiar
Średni a 6 5 3,5 3,0 4 2,5 2,0 1,5 3 1,0 0,5 AP 2 0,0-0,5 SI LR AP 3D Średni a±błąd std Średni a±odch.std 1 0 Σ = 1,2 mm σ = 1,2 mm -1-5 0 5 10 15 25 30 35 pomiar Direction Mean Minimum Maximum SD AP 1,2 0,0 5,0 1,2 SI 1,2 0,0 4,0 0,9 LR 0,4 0,0 2,0 0,6 3D 2,0 0,0 5,0 1,2 Vector = ( a = x²+y²+z²)
The value of migration (mm) Percentage of measurements SI LR AP 3D 0 % (6) 63% (19) 33% (10) 6% (2) 1 50% (15) 30% (9) 37% (11) 47% (14) 2 27% (8) 7% (2) 17% (5) 17% (5) >2 3% (1) 0% (0) 14% (4) 30% (9) 100 90 80 70 60 50 46 44 42 40 38 36 34 32 30 28 26 24 CT-CBCT 40 30 10 0-5 0 5 10 15 25 30 35 pomiar 22 18 16 CT-CBCT Σ = 31 days Min = 9 days Max= 87 days Średnia Średnia±Błąd std Średnia±Odch.std
100 90 80 70 60 50 90% 46 44 42 40 38 36 34 32 30 28 26 24 CT-CBCT 40 30 10 0-5 0 5 10 15 25 30 35 pomiar 22 18 16 CT-CBCT Σ = 31 days Min = 9 days Max= 87 days Średnia Średnia±Błąd std Średnia±Odch.std 40 22 35 18 16 30 14 12 25 10 8 -CT 6 4 -CT Średnia Średnia±Błąd std Średnia±Odch.std 15 10 5-5 0 5 10 15 25 30 35 Σ = 12 days Min = 7 days Max= 36 days pom iar
R Spearman p SI/time to CT LR/time to CT AP/time to CT 0,53 0,17 0,38 0,002 0,367 0,05 3D/time to CT 0,58 0,000 SI/CT-CBCT CBCT LR/CT-CBCT CBCT AP/CT-CBCT CBCT R Spearman 0,43 0,19 0,31 0,017 0,306 0,095 3D/CT-CBCT CBCT 0,48 0,007 p Conclusion During radiotherapy planning, the intraprostatic fiducial markers can migrate but probably it is not clinically relevant. Because of correlation between time from the implantation to the CBCT and the fiducials migration value, it is reasonable to not delay the radiotherapy start and to control the marker s location during the treatment..
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