Optimal usage of cone beam computed tomography system with different field of views in image guided radiotherapy (IGRT)

Narayana Venkata Naga Madhusudhana Sresty, Thogata Ramanjappa, Alluri Krishnam Raju, Adavala Mallikarjuna, Anil Talluri, Bhudevi Soubhagya


Purpose: To find methods for optimal usage of XVI (X-ray volume imaging) system in Elekta synergy linear accelerator with different field of views for same lesion in order to minimize patient dose due to imaging.

Methods: 20 scans of 2 individual patients with ca sigmoid colon and ca lung were used in this study. Kilo voltage collimators with medium field of view were used as per the preset information. Images were reconstructed for another collimator with small field of view. The set up errors were evaluated with XVI software. Shift results of both methods were compared.

Results: Variation in treatment set up errors with M20 and S20 collimators were ≤ 0.2 mm in translational and 0.30 in rotational shifts. Results showed almost equal translational and rotational shifts in both medium and small field of views with different collimators in all the scans. Visualization of target and surrounding structures were good enough and sufficient for XVI auto matching.

Conclusion: Imaging with small field of view results less patient dose compared with medium or large field of views. It is Suggestible to use collimators with small field of view wherever possible. In this study, collimators with small field of view were sufficient for both patients though the preset information indicated medium field of view. But, it always depends on the area required for matching purpose. So, individual selection is important than preset information in the XVI system.


XVI; Field of View; kV Collimator

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Jassal K, Munshi A, Sarkar B, et al. Validation of an integrated patient positioning system: Exactrac and iViewGT on Synergy Platform. Int J Cancer Ther Oncol 2014; 2:020212.

Alaei P, Spezi E. Commissioning kilovoltage cone-beam CT beams in a radiation therapy treatment planning system. J Appl Clin Med Phys 2012; 13:3971.

Huang Q, Zeng GL, You J, Gullberg GT. An FDK-like cone-beam SPECT reconstruction algorithm for non-uniform attenuated projections acquired using a circular trajectory. Phys Med Biol 2005; 50:2329-39.

Cho PS, Johnson RH, Griffin TW. Cone-beam CT for radiotherapy applications. Phys Med Biol 1995; 40:1863-83.

Ghilezan M, Yan D, Liang J, et al. Online image-guided intensity-modulated radiotherapy for prostate cancer: How much improvement can we expect? A theoretical assessment of clinical benefits and potential dose escalation by improving precision and accuracy of radiation delivery. Int J Radiat Oncol Biol Phys 2004; 60:1602-10.

Oldham M, Létourneau D, Watt L, et al. Cone-beam-CT guided radiation therapy: A model for on-line application. Radio ther Oncol 2005; 75:271-8.

Jaffray DA. Emergent technologies for 3-dimensional image-guided radiationdelivery. Semin Radiat Oncol 2005; 15:208-16.

Yan D, Lockman D, Martinez A, et al. Computed tomography guided management of interfractional patient variation. Semin Radiat Oncol 2005; 15:168-79.

Amer A, Marchant T, Sykes J, et al. Imaging doses from the Elekta Synergy X-ray cone beam CT system. Br J Radiol 2007; 80:476-82.

Kan MW, Leung LH, Wong W, Lam N. Radiation dose from cone beam computed tomography for image-guided radiation therapy. Int J Radiat Oncol BiolPhys 2008; 70:272-9.

Meyer J, Wilbert J, Baier K, et al. Positioning accuracy of cone-beam computed tomography in combination with a HexaPOD robot treatment table. Int J Radiat Oncol Biol Phys 2007; 67:1220-8.

DOI: http://dx.doi.org/10.14319/ijcto.33.4

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