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Sci—Fri PM: Delivery — 10: Imaging Developments for Broad Beam Co‐60 Radiation Therapy
Author(s) -
Rawluk N,
MacDonald A,
Marsh M,
Schreiner LJ,
Darko J,
Kerr A
Publication year - 2010
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3476198
Subject(s) - medical imaging , medical physics , image guided radiation therapy , radiation therapy , medicine , nuclear medicine , radiology
Accessibility is essential to providing quality health care. Our research work has shown that Cobalt‐60 (Co‐60) treatment can be modernized to provide intensity modulated radiation therapy (IMRT). The use of Co‐60 as a radiation source could provide a solution in parts of the world with limited infrastructure to support linac therapy. Previous work has been focused on tomotherapy; however, we have recently expanded to broad‐beam IMRT. This could potentially allow the existing fleet of over one thousand Co‐60 units to be upgraded instead of replaced. On‐board image guidance would be necessary to ensure tumour localization for precise IMRT treatment. Recent acquisition of an amorphous silicon (a‐Si) PortalVision aS500 (Varian Medical Systems, Palo Alto, CA) imaging panel has allowed testing of broad beam imaging modalities using a Co‐60 therapy unit (Best Theratronics T780C, Kanata, ON). Imaging with the therapy source could avoid the requirement of an additional lower activity source or kV imaging system. Portal imaging and cone‐beam computed tomography (CBCT) are widely used for image guidance with broad beam IMRT. Tomosynthesis imaging can provide depth discrimination information using a limited number of projections. Preliminary results clearly demonstrate that all three modalities are feasible with a therapy Co‐60 source and a‐Si imaging panel. Co‐60 CBCT resolution and image quality are comparable to previous fan‐beam scans. Co‐60 digital tomosynthesis (DT) is shown to enhance anatomical features at arbitrary depths. Thus DT has the potential to generate more useful information for patient setup verification than portal images while delivering less dose than CBCT.