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Session Item

Tuesday

August 31

09:15 - 10:30

N104

Surface-guided radiotherapy

Chair: Elisabeth Steiner, Austria;

Chair: Philipp Freislederer, Germany

Overview: Surface guided radiation therapy (SGRT) is recognized as a promising tool to enhance patient safety and increase treatment accuracy. SGRT can be applied for patient positioning and intrafractional motion monitoring, but also for special techniques, such as respiratory gating without any additional imaging dose. This session will cover the aspects of SGRT implementation in the clinic with an emphasis on staff training. Additionally, the challenges of SGRT, the main benefits for different tumour sites, and how to mitigate pitfalls will be highlighted. Deep-inspiration breath-hold radiotherapy for breast cancer will also be discussed as a success story of SGRT clinical implementation.

Session Type: Symposium

Track: Interdisciplinary

Journey:

10:05 - 10:30

Surface-guided radiotherapy for breast cancer in deep inspiration breath hold

Speaker: , Switzerland

Presentation Number: SP-0676

Abstract

Abstract Title:

Surface-guided radiotherapy for breast cancer in deep inspiration breath hold

Authors:

Karl Thomas Beer¹

¹Radio-Onkologie Zentrum Biel-Seeland-Berner Jura, -, Biel-Bienne, Switzerland

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Abstract Text

Rationale:

Implementation of Deep Inspiration Breathhold (DIBH) treatment with Surface Guided Radiotherapy (SGRT) to reduce heart toxicity in order to minimise excess cardiac toxicity

Methods:

Commissioning of SGRT system Align RT

Important considerations:

Shared decision by technicians, phycisists, and clinicians
Compatibility with treatment machines
Versatility
Ease of handling
Reduction of kV-MV imaging

Establish accuracy before universal application

Figure 1: Enhanced accuracy with SGRT

Figure 2: Selection of ROIs in breast cancer patients

Patient and Radiotherapy (RT) Treatment Data:

Patient Data:

Prospective evaluation of 44 consecutive left-sided breast cancer patients, mean age 63 years, 2 pts with bilateral breast cancer, 1 pt excluded (male, gynecomastia, total dose 20 Gy), total 43 pts
41 pts with breast conserving surgery, 2 with mastectomy

Treatment Data:

Mean dose 48 Gy, 31pts RT breast, 12 locoregional RT

Results:

Radiotherapy:

34 with DIBH, 9 free breathing, 34 pts with modulated techniques (33 IMRT, 1 VMAT), 9 3D conformal
28 pts with DIBH and modulated treatments, 6 pts with DIBH and conformal RT
6 pts with free breathe and modulated treatments, 3 pts with free breathe and 3D conformal RT
Mean age DIBH 61 years, free breathe 68 years

Heart and Lung Doses:

Mean heart dose 3D conformal 1.21 Gy, modulated technique 1.24 Gy
Mean lung dose 3D conformal 6.02 Gy, modulated technique 7.56 Gy
Mean heart dose DIBH 1.11 Gy, free breath 1.66 Gy
Mean lung dose DIBH 6.51 Gy, free breath 7.43 Gy

Handling:

No additional time for patient positioning after learning phase
Treatment times longer with highly modulated technique and DIBH
Easy implementation in clinical routine
Reduction of skin markings
High acceptance of pts

Conclusion:

Optimal sparing of normal tissue (heart and lung) with SGRT in DIBH
No influence of modulated versus 3D conformal techniques on normal tissue doses of the heart, but increased homogeneity of PTV coverage and reduction of hot spots
Compatible with modulated techniques in particular IMRT(only 1 pt with VMAT)
Easy handling and integration in daily practice
Reduction of skin markings

Our next steps taken:

Going marker free: more precision and patient comfort (3 of 120 pts still needed skin marks)
Applying SGRT to right sided patients in supine position with DIBH to achieve a standard work flow for all breast cancer pts
Apply SGRT to all pts with planning CT based RT

Take home messages:

Optimal sparing of normal tissue (heart and lung) with SGRT in DIBH
Compatible with modulated techniques (IMRT or VMAT)
Enhanced patient convenience (no skin markings or tattoos)
Standard workflow for left and right sided breast tumours