Commissioning of the Leksell Gamma Knife® Icon™. Issue 2 (30th January 2017)
- Record Type:
- Journal Article
- Title:
- Commissioning of the Leksell Gamma Knife® Icon™. Issue 2 (30th January 2017)
- Main Title:
- Commissioning of the Leksell Gamma Knife® Icon™
- Authors:
- Zeverino, Michele
Jaccard, Maud
Patin, David
Ryckx, Nick
Marguet, Maud
Tuleasca, Constantin
Schiappacasse, Luis
Bourhis, Jean
Levivier, Marc
Bochud, Francois O.
Moeckli, Raphaël - Abstract:
- Abstract : Purpose: The Leksell Gamma Knife (LGK) Icon has been recently introduced to provide Gamma Knife technology with frameless stereotactic treatments which use an additional cone‐beam CT (CBCT) imaging system and a motion tracking system (IFMM, Intra‐Fraction Motion Management). The system was commissioned for the treatment unit itself as well as the imaging system. Methods: The LGK Icon was calibrated using an A1SL ionization chamber. EBT3 radiochromic films were employed to independently check the machine calibration, to measure the relative output factors (ROFs) and to collect dose distributions. Coincidence between CBCT isocenter and radiological focus was evaluated by means of EBT3 films. CBCT image quality was investigated in terms of spatial resolution, contrast‐to‐noise ratio (CNR), and uniformity for the two presets available (low dose and high dose). Computed Tomography Dose Index (CTDI) was also measured for both presets. Results: The absolute dose rate of the LGK Icon was 3.86 ± 0.09 Gy/min. This result was confirmed by EBT3 readings. ROF were found to be 0.887 ± 0.035 and 0.797 ± 0.032 for the 8 mm and 4 mm collimators, respectively, which are within 2% of the Monte Carlo‐derived ROF values. Excellent agreement was found between calculated and measured dose distribution with the gamma pass rate >95% of points for the nine dose distributions analyzed with 3%/1 mm criteria. CBCT isocenter was found to be within 0.2 mm with respect to radiological focus.Abstract : Purpose: The Leksell Gamma Knife (LGK) Icon has been recently introduced to provide Gamma Knife technology with frameless stereotactic treatments which use an additional cone‐beam CT (CBCT) imaging system and a motion tracking system (IFMM, Intra‐Fraction Motion Management). The system was commissioned for the treatment unit itself as well as the imaging system. Methods: The LGK Icon was calibrated using an A1SL ionization chamber. EBT3 radiochromic films were employed to independently check the machine calibration, to measure the relative output factors (ROFs) and to collect dose distributions. Coincidence between CBCT isocenter and radiological focus was evaluated by means of EBT3 films. CBCT image quality was investigated in terms of spatial resolution, contrast‐to‐noise ratio (CNR), and uniformity for the two presets available (low dose and high dose). Computed Tomography Dose Index (CTDI) was also measured for both presets. Results: The absolute dose rate of the LGK Icon was 3.86 ± 0.09 Gy/min. This result was confirmed by EBT3 readings. ROF were found to be 0.887 ± 0.035 and 0.797 ± 0.032 for the 8 mm and 4 mm collimators, respectively, which are within 2% of the Monte Carlo‐derived ROF values. Excellent agreement was found between calculated and measured dose distribution with the gamma pass rate >95% of points for the nine dose distributions analyzed with 3%/1 mm criteria. CBCT isocenter was found to be within 0.2 mm with respect to radiological focus. Image quality parameters were found to be well within the manufacturer's specifications with the high‐dose preset being superior in terms of CNR and uniformity. CTDI values were 2.41 mGy and 6.32 mGy, i.e. −3.6% and 0.3% different from the nominal values for the low‐dose and high‐dose presets, respectively. Conclusions: The LGK Icon was successfully commissioned for clinical use. The use of the EBT3 to characterize the treatment unit was demonstrated to be feasible. The CBCT imaging system operates well within the manufacturer's specifications and provides good geometrical accuracy. … (more)
- Is Part Of:
- Medical physics. Volume 44:Issue 2(2017)
- Journal:
- Medical physics
- Issue:
- Volume 44:Issue 2(2017)
- Issue Display:
- Volume 44, Issue 2 (2017)
- Year:
- 2017
- Volume:
- 44
- Issue:
- 2
- Issue Sort Value:
- 2017-0044-0002-0000
- Page Start:
- 355
- Page End:
- 363
- Publication Date:
- 2017-01-30
- Subjects:
- CBCT -- CTDI -- film dosimetry -- Leksell Gamma Knife® Icon™ -- small field dosimetry
Medical physics -- Periodicals
Medical physics
Geneeskunde
Natuurkunde
Toepassingen
Biophysics
Periodicals
Periodicals
Electronic journals
610.153 - Journal URLs:
- http://scitation.aip.org/content/aapm/journal/medphys ↗
https://aapm.onlinelibrary.wiley.com/journal/24734209 ↗
http://www.aip.org/ ↗ - DOI:
- 10.1002/mp.12052 ↗
- Languages:
- English
- ISSNs:
- 0094-2405
- Deposit Type:
- Legaldeposit
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- Available online (eLD content is only available in our Reading Rooms) ↗
- Physical Locations:
- British Library DSC - 5531.130000
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