Dosimetrical evaluation of Leksell Gamma Knife 4C radiosurgery unit

• Authors: Thomas Sajeev , Mohamed Mustafa , Sanjay Supe
• Languages of publication: EN

Abstracts

EN

A number of experiments was performed using standard protocols, in order to evaluate the dosimetric accuracy of Leksell Gamma Knife 4C unit. Verification of the beam alignment has been performed for all collimators using solid plastic head phantom and Gafchromic™ type MD-55 films. The study showed a good agreement of Leksell Gammaplan calculated dose profiles with experimentally determined profiles in all three axes. Isocentric accuracy is verified using a specially machined cylindrical aluminium film holder tool made with very narrow geometric tolerances aligned between trunnions of 4 mm collimator. Considering all uncertainties in all three dimensions, the estimated accuracy of the unit was 0.1 mm. Dose rate at the centre point of the unit has been determined according to the IAEA, TRS-398 protocol, using Unidose-E (PTW-Freiburg, Germany) with a 0.125 cc ion chamber, over a period of 6 years. The study showed that the Leksell Gamma Knife 4C unit is excellent radiosurgical equipment with high accuracy and precision, which makes it possible to deliver larger doses of radiation, within the limits defined by national and international guidelines, applicable for stereotactic radiosurgery procedures.

Keywords

EN

Gamma knife; radiosurgery; dosimetry; Leksell; stereotactic; accuracy

• Publisher: Versita
• Journal: Polish Journal of Medical Physics And Engineering
• Year: 2011
• Volume: 17
• Issue: 3
• Pages: 105-120

Dates

published

1 - 1 - 2011

online

20 - 3 - 2012

Contributors

author

Thomas Sajeev

author

Mohamed Mustafa

• Department of Physics, University of Calicut, Kozhikode Kerala, India

author

Sanjay Supe

• Department of Radiation Physics, Kidwai Memorial Institute of Oncology, Banaglore, India

References

• Andrew Wu, Linder G, Maitz A.H, Kalend A. M., Lunsford L.D, Flickinger, Bloomer W.D, "Physics of gamma knife approach on convergent beams in stereotactic Radiosurgey" Int J. Radiation oncology biology physics, Vol-18(4),941-949,1990.
• IAEA "An International Code of Practice for Dosimetry Based on Standards of Absorbed Dose to Water" IAEA Technical Reports, Series No. 398
• AAPM Report 54 "Stereotactic Radiosurgery" Report of Task Group-42, Radiation Therapy Committee, June 95
• American College of Radiology-American Society for Radiation Oncology, "Practise guidelines for performance of stereotactic Radiosurgery, Revised" 2011,1-9
• L. Walton, C. K. Bomford, D. Ramsden "The scheffield stereotactic radiosurgery unit: physical characteristics and principles of operation" The British Journal of Radiology, September, 1987, 897-905.
• Mack A, Scheib SG, Major J, Gianolini S, Pazmandi G, Feist H, Czempiel H, Kreiner HJ, Precision dosimetry for narrow photon beams used in radiosurgery-determination of Gamma Knife output factors, Medical Physics 2002, September 29(9), 2080-2089.[Crossref]
• Stanley H. Benedict, Frank J Bova, Brenda Clark, et al, "Anniversary paper: the role of medical physicists in developing stereotactic radiosurgery" Medical Physics. 35(9),September 2008.

Identifiers

DOI

10.2478/v10013-011-0011-6