Patient movement and millimetre accurate positioning with SGRT

Rayk Nachtigall
Medical Physicist
Strahlenzentrum Hamburg MVZ, Germany

1. SZHH markerlessRT since2021
Rayk Nachtigall, medicalphysicist
Patient movementand
millimetreaccuratepositioning

2. Inhalt
•„Strahlenzentrum Hamburg MVZ“
•Implementation and experience
•Patient movement
•Thorax
•Abdomen/Pelvis
•Head & Neck
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3. Strahlenzentrum Hamburg MVZ
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•Foundedin 2007 (PD Dr. med. F. Fehlauer)
•2007 paper-andfilmless
•2008 IMRT/SBRT
•2011 Cyberknife

4. Strahlenzentrum Hamburg MVZ
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•2 siteswith50 employees
•Site Hamburg
2 Elektalinacs(HarmonyPro + Versa HD)
1 Cyberknife
•Site Elmshorn
1 VarianClinacDHX

5. Implementation andexperience
•2008 introductionABC gatingElekta
•2019 decisiontouseSGRT
→SGRT sitevisits(headsofRTT andphysics)
result:AlignRTismoreintuitive andunderstandable
•1
st
March 2021 installationAlignRTandSafeID
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6. Implementation andexperience
•30
th
April golive –all indications
Thorax RT
•30
th
June 2021 markerless
Other malignantentities
•August 2021 markerless
•23
rd
November 2021 MarkerlessAward
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7. Implementation andexperience
•SinceOctober2022 head& neck
•Open mask
•Resultofourexperience,
andgainconfidenceformaskless
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8. Patient movement
Entities
•Thorax
•Free breath203 patients→4000+ fractions
•DIBH 76 patients→1400+ fractions
•Abdomen/Pelvis
•40 patients→920+ fractions
•Head & Neck (open mask)
•20 patients→370+ fractions
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9. Patient movement
Analysis
•Gaussian-Analysis
•6000+ dataentriesper dimensionper fraction
•Meanpositionμ, deviationσ
•Spacialvectorv, integratedpatientmovementmarginm
99%=2.5σ
v
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10. Thorax
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11. Thorax
intertreatmentexample
FB DIBH
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-6
-4
-2
0
2
4
6
0 2 4 6 8 10 12 14 16 18
[mm]
mu vert
mu lng
mu lat
-6
-4
-2
0
2
4
6
0 2 4 6 8 10 12 14 16 18
[mm]

12. Thorax
meanpatientposition
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μ±σ(FB)
-1.3 ±1.2 mmvrt
0.1 ±0.7 mmlat
0.4 ±1.1 mmlng
μ±σ(DIBH)
-0.3 ±0.7 mmvrt
-0.2 ±0.8 mmlat
-0.5 ±1.3 mmlng

13. Thorax
patientpositionvector
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FB
2.75±1.09 mm
m
99%= 2.73 mm
DIBH
1.89±0.58 mm
m
99%= 1.45 mm

14. Abdomen/Pelvis
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15. Abdomen/Pelvis
meanpatientposition
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μ±σ
-0.5 ±0.9 mmvrt
0.1 ±0.6 mmlat
0.0 ±1.3 mmlng

16. Abdomen/Pelvis
patientpositionvector
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spacialvector
2.22±1.10 mm
m
99%= 2.75 mm

17. Head & Neck
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18. Head & Neck
meanpatientposition
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μ±σ
-0.2 ±0.5 mmvrt
-0.2 ±0.5 mmlat
0.0 ±0.5 mmlng

19. Head & Neck
patientpositionvector
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spacialvector
1.80±0.38 mm
m
99%= 0.95 mm

20. Patient movement
conclusion
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Head & Neck
m
99%= 0.95 mm
Abdomen/Pelvis
m
99%= 2.75 mm
Thorax
m
99%(FB) = 2.73 mm
m
99%(DIBH)= 1.45 mm
•DIBH recommendationforall thoracicRT
•2 mm safetymarginispossible
•Open masksandSGRT morethansufficient

21. Thankyou!
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22. You‘reinvitedtovisitusin
Hamburg
R N a c h t i g a l l @ s z h h . d eR. NachtigallSGRT Europe 2023 22