A comprehensive evaluation of treatment accuracy, including end-to-end tests and clinical data, applied to intracranial stereotactic radiotherapy. Issue 1 (July 2015)

• Record Type: Journal Article
• Authors: Seravalli, E.; van Haaren, P.M.A.; van der Toorn, P.P.; Hurkmans, C.W.
• Is Part Of: Radiotherapy and oncology. Volume 116:Issue 1(2015:Jul.)
• Page Start: 131
• Page End: 138
• Publication Date: 2015-07
• Subjects: Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2015.06.004
• Languages: English
• ISSNs: 0167-8140

Abstract

<abstract xml:lang="en" abstract-type="author" id="ab005"> <title id="st005">Abstract</title> <sec> <title id="st010">Background and purpose</title> <p id="sp0005">A methodology is presented to quantify the uncertainty associated with linear accelerator-based frameless intracranial stereotactic radiotherapy (SRT) combining end-to-end phantom tests and clinical data.</p> </sec> <sec> <title id="st015">Methods and materials</title> <p id="sp0010">The following steps of the SRT chain were analysed: planning computed tomography (CT) and magnetic resonance (MR) scans registration, target volume delineation, CT and cone beam CT (CBCT) registration and intrafraction-patient displacement. The overall accuracy was established with an end-to-end test. The measured uncertainties were combined, deriving the total systematic (<italic>Σ</italic><sub>T</sub>) and random (<italic>σ</italic><sub>T</sub>) error components, to estimate the GTV-PTV margin.</p> </sec> <sec> <title id="st020">Results</title> <p id="sp0015">The uncertainty in the MR-CT registration was on average 0.40 mm (averaged over AP, CC and LR directions). Rotational variations were smaller than 0.5° in all directions.</p> <p id="sp0020">Interobser variation in GTV delineation was on average 0.29 mm.</p> <p id="sp0025">The uncertainty in the CBCT-CT registration was on average 0.15 mm. Again, rotational variations were smaller than 0.5° in all directions.</p> <p id="sp0030">The systematic and random intrafraction displacement errors were on average 0.55 mm and 0.45 mm, respectively.</p> <p id="sp0035">The systematic and random positional errors from the end-to-end test were on average 0.49 mm and 0.53 mm, respectively.</p> <p id="sp0040">Combining these uncertainties resulted in an average <italic>Σ</italic><sub>T</sub> = 0.9 mm and <italic>σ</italic><sub>T</sub> = 0.7 mm and an average GTV-PTV margin of 2.8 mm.</p> </sec> <sec> <title id="st025">Conclusion</title> <p id="sp0045">This comprehensive methodology including end-to-end tests enabled a GTV-PTV margin calculation considering all sources of uncertainties. This generic method can also be used for other treatment sites.</p> </sec> </abstract>