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Surface guided electron FLASH radiotherapy for canine cancer patients

Mannerberg, Annika LU ; Konradsson, Elise LU ; Kügele, Malin LU orcid ; Edvardsson, Anneli LU ; Kadhim, Mustafa LU ; Ceberg, Crister LU orcid ; Petersson, Kristoffer LU ; Thomasson, Hanna-Maria ; Arendt, Maja L. and Børresen, Betina , et al. (2023) In Medical Physics 50(7). p.4047-4054
Abstract
Background
During recent years FLASH radiotherapy (FLASH-RT) has shown promising results in radiation oncology, with the potential to spare normal tissue while maintaining the antitumor effects. The high speed of the FLASH-RT delivery increases the need for fast and precise motion monitoring to avoid underdosing the target. Surface guided radiotherapy (SGRT) uses surface imaging (SI) to render a 3D surface of the patient. SI provides real-time motion monitoring and has a large scanning field of view, covering off-isocentric positions. However, SI has so far only been used for human patients with conventional setup and treatment.

Purpose
The aim of this study was to investigate the performance of SI as a motion management... (More)
Background
During recent years FLASH radiotherapy (FLASH-RT) has shown promising results in radiation oncology, with the potential to spare normal tissue while maintaining the antitumor effects. The high speed of the FLASH-RT delivery increases the need for fast and precise motion monitoring to avoid underdosing the target. Surface guided radiotherapy (SGRT) uses surface imaging (SI) to render a 3D surface of the patient. SI provides real-time motion monitoring and has a large scanning field of view, covering off-isocentric positions. However, SI has so far only been used for human patients with conventional setup and treatment.

Purpose
The aim of this study was to investigate the performance of SI as a motion management tool during electron FLASH-RT of canine cancer patients.
Methods
To evaluate the SI system's ability to render surfaces of fur, three fur-like blankets in white, grey, and black were used to imitate the surface of canine patients and the camera settings were optimized for each blanket. Phantom measurements using the fur blankets were carried out, simulating respiratory motion and sudden shift. Respiratory motion was simulated using the QUASAR Respiratory Motion Phantom with the fur blankets placed on the phantom platform, which moved 10 mm vertically with a simulated respiratory period of 4 s. Sudden motion was simulated with an in-house developed phantom, consisting of a platform which was moved vertically in a stepwise motion at a chosen frequency. For sudden measurements, 1, 2, 3, 4, 5, 6, 7, and 10 Hz were measured. All measurements were both carried out at the conventional source-to-surface distance (SSD) of 100 cm, and in the locally used FLASH-RT setup at SSD = 70 cm. The capability of the SI system to reproduce the simulated motion and the sampling time were evaluated. As an initial step towards clinical implementation, the feasibility of SI for surface guided FLASH-RT was evaluated for 11 canine cancer patients.

Results
The SI camera was capable of rendering surfaces for all blankets. The deviation between simulated and measured mean peak-to-peak breathing amplitude was within 0.6 mm for all blankets. The sampling time was generally higher for the black fur than for the white and grey fur, for the measurement of both respiratory and sudden motion. The SI system could measure sudden motion within 62.5 ms and detect motion with a frequency of 10 Hz. The feasibility study of the canine patients showed that the SI system could be an important tool to ensure patient safety. By using this system we could ensure and document that 10 out of 11 canine patients had a total vector offset from the reference setup position
Conclusions
We have shown that SI can be used for surface guided FLASH-RT of canine patients. The SI system is currently not fast enough to interrupt a FLASH-RT beam while irradiating but with the short sampling time sudden motion can be detected. The beam can therefore be held just prior to irradiation, preventing treatment errors such as underdosing the target.
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
FLASH radiotherapy, surface guided radiotherapy, SGRT
in
Medical Physics
volume
50
issue
7
pages
4047 - 4054
publisher
American Association of Physicists in Medicine
external identifiers
  • pmid:37190907
  • scopus:85159280432
ISSN
0094-2405
DOI
10.1002/mp.16453
language
English
LU publication?
yes
id
39d9d5b3-91c9-4ee7-8696-c604cf068ad9
date added to LUP
2023-05-23 13:14:52
date last changed
2023-10-26 14:48:02
@article{39d9d5b3-91c9-4ee7-8696-c604cf068ad9,
  abstract     = {{Background<br/>During recent years FLASH radiotherapy (FLASH-RT) has shown promising results in radiation oncology, with the potential to spare normal tissue while maintaining the antitumor effects. The high speed of the FLASH-RT delivery increases the need for fast and precise motion monitoring to avoid underdosing the target. Surface guided radiotherapy (SGRT) uses surface imaging (SI) to render a 3D surface of the patient. SI provides real-time motion monitoring and has a large scanning field of view, covering off-isocentric positions. However, SI has so far only been used for human patients with conventional setup and treatment.<br/><br/>Purpose<br/>The aim of this study was to investigate the performance of SI as a motion management tool during electron FLASH-RT of canine cancer patients.<br/>Methods<br/>To evaluate the SI system's ability to render surfaces of fur, three fur-like blankets in white, grey, and black were used to imitate the surface of canine patients and the camera settings were optimized for each blanket. Phantom measurements using the fur blankets were carried out, simulating respiratory motion and sudden shift. Respiratory motion was simulated using the QUASAR Respiratory Motion Phantom with the fur blankets placed on the phantom platform, which moved 10 mm vertically with a simulated respiratory period of 4 s. Sudden motion was simulated with an in-house developed phantom, consisting of a platform which was moved vertically in a stepwise motion at a chosen frequency. For sudden measurements, 1, 2, 3, 4, 5, 6, 7, and 10 Hz were measured. All measurements were both carried out at the conventional source-to-surface distance (SSD) of 100 cm, and in the locally used FLASH-RT setup at SSD = 70 cm. The capability of the SI system to reproduce the simulated motion and the sampling time were evaluated. As an initial step towards clinical implementation, the feasibility of SI for surface guided FLASH-RT was evaluated for 11 canine cancer patients.<br/><br/>Results<br/>The SI camera was capable of rendering surfaces for all blankets. The deviation between simulated and measured mean peak-to-peak breathing amplitude was within 0.6 mm for all blankets. The sampling time was generally higher for the black fur than for the white and grey fur, for the measurement of both respiratory and sudden motion. The SI system could measure sudden motion within 62.5 ms and detect motion with a frequency of 10 Hz. The feasibility study of the canine patients showed that the SI system could be an important tool to ensure patient safety. By using this system we could ensure and document that 10 out of 11 canine patients had a total vector offset from the reference setup position <br/>Conclusions<br/>We have shown that SI can be used for surface guided FLASH-RT of canine patients. The SI system is currently not fast enough to interrupt a FLASH-RT beam while irradiating but with the short sampling time sudden motion can be detected. The beam can therefore be held just prior to irradiation, preventing treatment errors such as underdosing the target.<br/>}},
  author       = {{Mannerberg, Annika and Konradsson, Elise and Kügele, Malin and Edvardsson, Anneli and Kadhim, Mustafa and Ceberg, Crister and Petersson, Kristoffer and Thomasson, Hanna-Maria and Arendt, Maja L. and Børresen, Betina and Bastholm Jensen, Kristine and Ceberg, Sofie}},
  issn         = {{0094-2405}},
  keywords     = {{FLASH radiotherapy; surface guided radiotherapy; SGRT}},
  language     = {{eng}},
  number       = {{7}},
  pages        = {{4047--4054}},
  publisher    = {{American Association of Physicists in Medicine}},
  series       = {{Medical Physics}},
  title        = {{Surface guided electron FLASH radiotherapy for canine cancer patients}},
  url          = {{http://dx.doi.org/10.1002/mp.16453}},
  doi          = {{10.1002/mp.16453}},
  volume       = {{50}},
  year         = {{2023}},
}