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5. MRI guidance for breast cancer radiotherapy

Author

Lagendijk, J.J.W., Bongard, H.J.G.D. van den, Houweling, A.C., Groot Koerkamp, Maureen Leonie, Lagendijk, J.J.W., Bongard, H.J.G.D. van den, Houweling, A.C., and Groot Koerkamp, Maureen Leonie

Published
2022

7. MRI guidance for breast cancer radiotherapy

Author

Lagendijk, J.J.W., Bongard, H.J.G.D. van den, Houweling, A.C., Groot Koerkamp, Maureen Leonie, Lagendijk, J.J.W., Bongard, H.J.G.D. van den, Houweling, A.C., and Groot Koerkamp, Maureen Leonie

Published
2022

9. Intrafraction motion tracking for MR-Linac prostate radiotherapy

Author

Lagendijk, J.J.W., Raaymakers, B.W., Boer, J.C.J. de, Voort van Zyp, J.R.N. van der, Muinck Keizer, Daan Maarten de, Lagendijk, J.J.W., Raaymakers, B.W., Boer, J.C.J. de, Voort van Zyp, J.R.N. van der, and Muinck Keizer, Daan Maarten de

Published
2021

13. Intrafraction motion tracking for MR-Linac prostate radiotherapy

Author

Lagendijk, J.J.W., Raaymakers, B.W., Boer, J.C.J. de, Voort van Zyp, J.R.N. van der, Muinck Keizer, Daan Maarten de, Lagendijk, J.J.W., Raaymakers, B.W., Boer, J.C.J. de, Voort van Zyp, J.R.N. van der, and Muinck Keizer, Daan Maarten de

Published
2021

17. Intrafraction motion tracking for MR-Linac prostate radiotherapy

Author

Lagendijk, J.J.W., Raaymakers, B.W., Boer, J.C.J. de, Voort van Zyp, J.R.N. van der, Muinck Keizer, Daan Maarten de, Lagendijk, J.J.W., Raaymakers, B.W., Boer, J.C.J. de, Voort van Zyp, J.R.N. van der, and Muinck Keizer, Daan Maarten de

Published
2021

20. Intrafraction motion tracking for MR-Linac prostate radiotherapy

Author

Lagendijk, J.J.W., Raaymakers, B.W., Boer, J.C.J. de, Voort van Zyp, J.R.N. van der, Muinck Keizer, Daan Maarten de, Lagendijk, J.J.W., Raaymakers, B.W., Boer, J.C.J. de, Voort van Zyp, J.R.N. van der, and Muinck Keizer, Daan Maarten de

Published
2021

29. Understanding the physical relations governing the noise navigator

Author

Navest, R.J.M., Mandija, S., Andreychenko, A., Raaijmakers, Aalexander J.E., Lagendijk, J.J.W., van den Berg, C.A.T., Navest, R.J.M., Mandija, S., Andreychenko, A., Raaijmakers, Aalexander J.E., Lagendijk, J.J.W., and van den Berg, C.A.T.

Abstract

Purpose: The noise navigator is a passive way to detect physiological motion occurring in a patient through thermal noise modulations measured by standard clinical radiofrequency receive coils. The aim is to gain a deeper understanding of the potential and applications of physiologically induced thermal noise modulations. Methods: Numerical electromagnetic simulations and MR measurements were performed to investigate the relative contribution of tissue displacement versus modulation of the dielectric lung properties over the respiratory cycle, the impact of coil diameter and position with respect to the body. Furthermore, the spatial motion sensitivity of specific noise covariance matrix elements of a receive array was investigated. Results: The influence of dielectric lung property variations on the noise variance is negligible compared to tissue displacement. Coil size affected the thermal noise variance modulation, but the location of the coil with respect to the body had a larger impact. The modulation depth of a 15 cm diameter stationary coil approximately 3 cm away from the chest (i.e. radiotherapy setup) was 39.7% compared to 4.2% for a coil of the same size on the chest, moving along with respiratory motion. A combination of particular noise covariance matrix elements creates a specific spatial sensitivity for motion. Conclusions: The insight gained on the physical relations governing the noise navigator will allow for optimized use and development of new applications. An optimized combination of elements from the noise covariance matrix offer new ways of performing, e.g. motion tracking.

Published
2019

30. Understanding the physical relations governing the noise navigator

Author

Navest, R.J.M., Mandija, S., Andreychenko, A., Raaijmakers, Aalexander J.E., Lagendijk, J.J.W., van den Berg, C.A.T., Navest, R.J.M., Mandija, S., Andreychenko, A., Raaijmakers, Aalexander J.E., Lagendijk, J.J.W., and van den Berg, C.A.T.

Abstract

Purpose: The noise navigator is a passive way to detect physiological motion occurring in a patient through thermal noise modulations measured by standard clinical radiofrequency receive coils. The aim is to gain a deeper understanding of the potential and applications of physiologically induced thermal noise modulations. Methods: Numerical electromagnetic simulations and MR measurements were performed to investigate the relative contribution of tissue displacement versus modulation of the dielectric lung properties over the respiratory cycle, the impact of coil diameter and position with respect to the body. Furthermore, the spatial motion sensitivity of specific noise covariance matrix elements of a receive array was investigated. Results: The influence of dielectric lung property variations on the noise variance is negligible compared to tissue displacement. Coil size affected the thermal noise variance modulation, but the location of the coil with respect to the body had a larger impact. The modulation depth of a 15 cm diameter stationary coil approximately 3 cm away from the chest (i.e. radiotherapy setup) was 39.7% compared to 4.2% for a coil of the same size on the chest, moving along with respiratory motion. A combination of particular noise covariance matrix elements creates a specific spatial sensitivity for motion. Conclusions: The insight gained on the physical relations governing the noise navigator will allow for optimized use and development of new applications. An optimized combination of elements from the noise covariance matrix offer new ways of performing, e.g. motion tracking.

Published
2019

31. Supine MRI for regional breast radiotherapy: Imaging axillary lymph nodes before and after sentinel-node biopsy

Author

Van Heijst, T.C.F. (Tristan C. F.), Eschbach-Zandbergen, D. (Debora), Hoekstra, N. (Nienke), Van Asselen, B. (Bram), Lagendijk, J.J.W. (Jan), Verkooijen, H.M. (Helena), Pijnappel, W.W.M.P. (Pim), De Waard, S.N. (Stephanie N.), Witkamp, A.J. (A.), Dalen, T. (Thijs) van, Van Den Bongard, H.J.G.D. (H. J. G. Desirée), Philippens, M.E.P. (Marielle E. P.), Van Heijst, T.C.F. (Tristan C. F.), Eschbach-Zandbergen, D. (Debora), Hoekstra, N. (Nienke), Van Asselen, B. (Bram), Lagendijk, J.J.W. (Jan), Verkooijen, H.M. (Helena), Pijnappel, W.W.M.P. (Pim), De Waard, S.N. (Stephanie N.), Witkamp, A.J. (A.), Dalen, T. (Thijs) van, Van Den Bongard, H.J.G.D. (H. J. G. Desirée), and Philippens, M.E.P. (Marielle E. P.)

Abstract

Regional radiotherapy (RT) is increasingly used in breast cancer treatment. Conventionally, computed tomography (CT) is performed for RT planning. Lymph node (LN) target levels are delineated according to anatomical boundaries. Magnetic resonance imaging (MRI) could enable individual LN delineation. The purpose was to evaluate the applicability of MRI for LN detection in supine treatment position, before and after sentinel-node biopsy (SNB). Twenty-three female breast cancer patients (cTis-3N0M0) underwent 1.5 T MRI, before and after SNB, in addition to CT. Endurance for MRI was monitored. Axillary levels were delineated. LNs were identified and delineated on MRI from before and after SNB, and on CT, and compared by Wilcoxon signed-rank tests. LN locations and LN-based volumes were related to axillary delineations and associated volumes. Although postoperative effects were visible, LN numbers on postoperative MRI (median 26 LNs) were highly reproducible compared to preoperative MRI when adding excised sentinel nodes, and higher than on CT (median 11, p < 0.001). LN-based volumes were considerably smaller than respective axillary levels. Supine MRI of LNs is feasible and reproducible before and after SNB. This may lead to more accurate RT target definition compared to CT, with potentially lower toxicity. With the MRI techniques described here, initiation of novel MRI-guided RT strategies aiming at individual LNs could be possible.

Published
2017
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35. Dosimetry for the MR-linac

Author

Lagendijk, J.J.W., Raaymakers, B.W., Smit, K., Lagendijk, J.J.W., Raaymakers, B.W., and Smit, K.

Published
2015

40. Dosimetry for the MR-linac

Author

Lagendijk, J.J.W., Raaymakers, B.W., Smit, K., Lagendijk, J.J.W., Raaymakers, B.W., and Smit, K.

Published
2015

46. Dosimetry for the MR-linac

Author

Lagendijk, J.J.W., Raaymakers, B.W., Smit, K., Lagendijk, J.J.W., Raaymakers, B.W., and Smit, K.

Published
2015

48. Dosimetry for the MR-linac

Author

Lagendijk, J.J.W., Raaymakers, B.W., Smit, K., Lagendijk, J.J.W., Raaymakers, B.W., and Smit, K.

Published
2015

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