However, it is impossible to completely avoid this uncertainty in stereotactic body radiotherapy (SBRT) and frameless stereotactic radiosurgery (SRS), in part due to long treatment times caused by large fractional doses.Jeppesen, MD, 2, 3 and Olfred Hansen, PhD, MD 2, 3 Morten Nielsen 1 Laboratory of Radiation Physics, Odense University Hospital, 29 Sdr.
Boulevard, DK-5000 Odense C, Denmark Find articles by Morten Nielsen Christian R. Hansen 1 Laboratory of Radiation Physics, Odense University Hospital, 29 Sdr. Boulevard, DK-5000 Odense C, Denmark Find articles by Christian R. Hansen Carsten Brink 1 Laboratory of Radiation Physics, Odense University Hospital, 29 Sdr. ![]() Bertelsen 1 Laboratory of Radiation Physics, Odense University Hospital, 29 Sdr. Boulevard, DK-5000 Odense C, Denmark Find articles by Anders S. Bertelsen Charlotte Kristiansen 3 Department of Oncology, Odense University Hospital, 29 Sdr. Boulevard, DK-5000 Odense C, Denmark Find articles by Charlotte Kristiansen Stefan S. Jeppesen 2 Department of Clinical Research, University of Southern Denmark, 19 Winslwparken, DK-5000 Odense C, Denmark 3 Department of Oncology, Odense University Hospital, 29 Sdr. Boulevard, DK-5000 Odense C, Denmark Find articles by Stefan S. Jeppesen Olfred Hansen 2 Department of Clinical Research, University of Southern Denmark, 19 Winslwparken, DK-5000 Odense C, Denmark 3 Department of Oncology, Odense University Hospital, 29 Sdr. Pinnacle Treatment Planning System User License Information DisclaimerBoulevard, DK-5000 Odense C, Denmark Find articles by Olfred Hansen Author information Article notes Copyright and License information Disclaimer 1 Laboratory of Radiation Physics, Odense University Hospital, 29 Sdr. Boulevard, DK-5000 Odense C, Denmark 2 Department of Clinical Research, University of Southern Denmark, 19 Winslwparken, DK-5000 Odense C, Denmark 3 Department of Oncology, Odense University Hospital, 29 Sdr. Boulevard, DK-5000 Odense C, Denmark Corresponding author. Correspondence to: Morten Nielsen, Laboratory of Radiation Physics, Odense University Hospital, 29 Sdr. Boulevard, DK-5000 Odense C, Denmark; Email: kd.dysrneslein.netrom; Phone: 45 29796480; Fax: 45 65413919 Received 2016 Jan 27; Accepted 2016 Mar 16. Pinnacle Treatment Planning System User License Under ThePublished by license under the OCP Science imprint, a member of the Old City Publishing Group. Abstract Flattening filter free (FFF) high dose rate beam technique was introduced for brain stereotactic radiosurgery (SRS) and lung Stereotactic Body Radiotherapy (SBRT). Furthermore, a HexaPOD treatment table was introduced for the brain SRS to enable correction of rotational setup errors. FF) and 57 FFF brain SRS treatments, as well as 451 FF and 294 FFF lung SBRT treatments were evaluated to assess differences in intrafractional motion (IFM) between FF and FFF treatments. For brain SRS the accuracy of rotational corrections was assessed as well. For SRS the treatment time was reduced by 21, and for SBRT the treatment time was reduced by 25. However, only for SBRT the IFM was significantly reduced, from 1.9 mm to 1.6 mm. For brain SRS, table correction in 6D greatly improves patient setup precision observed as a reduction in mean residual rotational setup error from 0.3 (SD1.2) to 0.06 (SD 0.3). Keywords: SRS, SBRT, stereotactic, brain, lung, FFF, intrafractional motion, rotations, HexaPOD 1. Introduction The central issue in radiotherapy is the balance between the desired effect, shrinkage or eradication of tumour manifestations, and normal tissue complications arising from irradiation of healthy tissue. Serious normal tissue complications typically arise either when large proportion of the volume of a parallel organ, e.g. For both intra- and extracranial stereotactic radiotherapy, precise and accurate delineation, planning, image guidance, and treatment techniques are used to allow planning and delivery of very conformal dose distributions. This minimises the irradiated volume of healthy tissue surrounding the tumour, and allows a separation of tumour and critical structure to ensure that even critical structures close to the intended target receives doses well below the treatment dose. In this way, stereotactic radiotherapy can deliver very high doses to small treatment volumes while unwanted side effects are minimised. Even in this precise and accurate stereotactic regime, a variety of causes lead to spatial uncertainties. Image guided treatment (IGRT) on a linear accelerator is typically preceded by cone beam CT (CBCT) imaging which is compared with a reference CT scan allowing for discrepancies to be corrected by moving the treatment table 2. However, the table motion is not perfect 3 and is traditionally restricted to translations in the 3 orthogonal directions. Rotational components are typically not corrected; instead the rotational localisation error is sought reduced by careful immobilisation of the patient 4. Immobilisation also minimises intrafractional motion (IFM) of the patient.
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