Technical note: Cryostat transmission characterization for MR linac – temporal stability, clinical impact and change implementation
Fuente:
Wiley Open Access
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Artículo Open Access |
| Published: |
Wiley
2024
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1867013222961250304 |
|---|---|
| author | Urszula Jelen Claire Pagulayan Zoë Moutrie Jason Arts Armia George Michael G. Jameson |
| author_facet | Urszula Jelen Claire Pagulayan Zoë Moutrie Jason Arts Armia George Michael G. Jameson Urszula Jelen Claire Pagulayan Zoë Moutrie Jason Arts Armia George Michael G. Jameson |
| collection | Wiley Open Access |
| contents | Technical note: Cryostat transmission characterization for MR linac – temporal stability, clinical impact and change implementation Urszula Jelen Claire Pagulayan Zoë Moutrie Jason Arts Armia George Michael G. Jameson Medical Physics AbstractBackgroundIn the Unity MR linac (Elekta AB, Stockholm, Sweden), the radiation beam traverses the cryostat and the coil support structure. The resulting beam attenuation must be considered for output calibration and its variation with gantry angle must be characterized in the treatment planning system (TPS).PurposeThe aim of this work was to investigate the impact of a change of the cryostat transmission characterization (CTC) curve, due to the helium level modification, on clinical treatment plan dosimetry and to report on the experience with the CTC curve update.MethodsTwenty stereotactic body radiotherapy (SBRT) treatment plans: 10 prostate and 10 oligo‐metastatic cancer plans, prepared with a beam model incorporating the CTC curve acquired at installation time, were re‐calculated using the model implementing CTC curve post helium top‐up. To account for the CTC change as well as to align our system to the recent reference conditions recommendations, the new model was commissioned with the emphasis on the specifics associated with the treatment plan adaptation and the existence of the offline and online TPS components.ResultsAverage CTV mean dose reduction by 0.45% in prostate cases and average GTV mean dose reduction by 0.22% in oligo‐metastatic cases was observed. Updated model validation showcased good agreement between measurements and TPS calculations.ConclusionsThe agreement between CTC measurements demonstrates its temporal constancy and robustness of the measurement method employed. A helium fill level change was shown to affect the CTC and led to a small but systematic dose calculation inaccuracy. Finally, model validation and end‐to‐end testing results presented, underscore the minimal impact of transitioning to the new beam model and new reference conditions. 10.1002/mp.17021 http://onlinelibrary.wiley.com/termsAndConditions#vor |
| doi_str_mv | 10.1002/mp.17021 |
| format | Artículo Open Access |
| id | wiley_oa_10_1002_mp_17021 |
| institution | Wiley Open Access |
| license_str_mv | http://onlinelibrary.wiley.com/termsAndConditions#vor |
| publishDate | 2024 |
| publisher | Wiley |
| record_format | wiley_oa |
| spellingShingle | Technical note: Cryostat transmission characterization for MR linac – temporal stability, clinical impact and change implementation Urszula Jelen Claire Pagulayan Zoë Moutrie Jason Arts Armia George Michael G. Jameson Medical Physics Technical note: Cryostat transmission characterization for MR linac – temporal stability, clinical impact and change implementation Urszula Jelen Claire Pagulayan Zoë Moutrie Jason Arts Armia George Michael G. Jameson Medical Physics AbstractBackgroundIn the Unity MR linac (Elekta AB, Stockholm, Sweden), the radiation beam traverses the cryostat and the coil support structure. The resulting beam attenuation must be considered for output calibration and its variation with gantry angle must be characterized in the treatment planning system (TPS).PurposeThe aim of this work was to investigate the impact of a change of the cryostat transmission characterization (CTC) curve, due to the helium level modification, on clinical treatment plan dosimetry and to report on the experience with the CTC curve update.MethodsTwenty stereotactic body radiotherapy (SBRT) treatment plans: 10 prostate and 10 oligo‐metastatic cancer plans, prepared with a beam model incorporating the CTC curve acquired at installation time, were re‐calculated using the model implementing CTC curve post helium top‐up. To account for the CTC change as well as to align our system to the recent reference conditions recommendations, the new model was commissioned with the emphasis on the specifics associated with the treatment plan adaptation and the existence of the offline and online TPS components.ResultsAverage CTV mean dose reduction by 0.45% in prostate cases and average GTV mean dose reduction by 0.22% in oligo‐metastatic cases was observed. Updated model validation showcased good agreement between measurements and TPS calculations.ConclusionsThe agreement between CTC measurements demonstrates its temporal constancy and robustness of the measurement method employed. A helium fill level change was shown to affect the CTC and led to a small but systematic dose calculation inaccuracy. Finally, model validation and end‐to‐end testing results presented, underscore the minimal impact of transitioning to the new beam model and new reference conditions. 10.1002/mp.17021 http://onlinelibrary.wiley.com/termsAndConditions#vor |
| title | Technical note: Cryostat transmission characterization for MR linac – temporal stability, clinical impact and change implementation |
| topic | Medical Physics |
| url | https://aapm.onlinelibrary.wiley.com/doi/10.1002/mp.17021 |