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01.02.2012 | Original article

Dosimetric integration of daily mega-voltage cone-beam CT for image-guided intensity-modulated radiotherapy

verfasst von: PD Dr. A. Zabel-du Bois, S. Nill, S. Ulrich, U. Oelfke, B. Rhein, P. Haering, S. Milker-Zabel, A. Schwahofer

Erschienen in: Strahlentherapie und Onkologie | Ausgabe 2/2012

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Abstract

Purpose

The goal of this work was to compare different methods of incorporating the additional dose of mega-voltage cone-beam CT (MV-CBCT) for image-guided intensity modulated radiotherapy (IMRT) of different tumor entities.

Material and methods

The absolute dose delivered by the MV-CBCT was calculated and considered by creating a scaled IMRT plan (scIMRT) by renormalizing the clinically approved plan (orgIMRT) so that the sum with the MV-CBCT dose yields the same prescribed dose. In the other case, a newly optimized plan (optIMRT) was generated by including the dose distribution of the MV-CBCT as pre-irradiation. Both plans were compared with the orgIMRT plan and a plan where the last fraction was skipped.

Results

No significant changes were observed regarding the 95% conformity index of the target volume. The mean dose of the organs at risk (OAR) increased by approx. 7% for the scIMRT plan and 5% for the optIMRT plan. A significant increase of the mean dose to the outline contour was observed, ranging from 3.1 ± 1.3% (optIMRT) to 13.0 ± 6.1% (scIMRT) for both methods over all entities. If the dose of daily MV-CBCT would have been ignored, the additional dose accumulated to nearly a whole treatment fraction with a general increase of approx. 10% to the OARs and approx. 4% to the target volume.

Conclusion

Both methods of incorporating the additional MV-CBCT dose into the treatment plan are suitable for clinical practice. The dose distribution of the target volume could be achieved as conformal as with the orgIMRT plan, while only a moderate increase of mean dose to OAR was observed.

Bentel GC, Marks LB, Sherouse GW et al (1995) A customized head and neck support system. Int J Radiat Oncol Biol Phys 32:245–248PubMedCrossRef

Dörr W, Herrmann T (2002) Second primary tumors after radiotherapy for malignancies. Strahlenther Onkol 178:357–362PubMedCrossRef

Fiorino C, Reni M, Bolognesi A et al (1998) Set-up error in supine-positioned patients immobilized with two different modalities during conformal radiotherapy of prostate cancer. Radiother Oncol 49:133–141PubMedCrossRef

Gayou O, Parda DS, Johnson M et al (2007) Patient dose and image quality from mega-voltage cone beam computed tomography imaging. Med Phys 34:499–506PubMedCrossRef

Guckenberger M, Ok S, Polat B et al (2010) Toxicity after intensity-modulated, image-guided radiotherapy for prostate cancer. Strahlenther Onkol 186:535–543. Erratum in: Strahlenther Onkol 186:705

Hall EJ, Wuu CS (2003) Radiation-induced second cancers: the impact of 3D-CRT and IMRT. Int J Radiat Oncol Biol Phys 56:83–88PubMedCrossRef

Hermanto U, Frija EK, Lii MJ et al (2007) Intensity modulated radiotherapy (IMRT) and conventional three-dimensional conformal radiotherapy for high grade gliomas: does IMRT increase the integral dose to normal brain? Int J Radiat Oncol Biol Phys 67:1135–1144PubMedCrossRef

Hong TS, Tome WA, Chappell RJ et al (2005) The impact of daily setup variations on head-and-neck intensity-modulated radiation therapy. Int J Radiat Oncol Biol Phys 61:779–788PubMedCrossRef

Kapanen M, Collan J, Saarilahti K et al (2009) Accuracy requirements for head and neck intensity-modulated radiation therapy based on observed dose response of the major salivary glands. Radiother Oncol 93:109–114PubMedCrossRef

10.

Kry SF, Salehpour M, Followill DS et al (2005) The calculated risk of secondary malignancies from intensity-modulated radiation therapy. Int J Radiat Oncol Biol Phys 62:1195–1203PubMedCrossRef

11.

Miften M, Gayou O, Reitz B et al (2007) IMRT planning and delivery incorporating daily dose from mega-voltage cone-beam computed tomography imaging. Med Phys 34:3760–3767PubMedCrossRef

12.

Milker-Zabel S, Zabel-du Bois A, Huber P et al (2007) Intensity-modulated radiotherapy for complex-shaped meningioma of the skull base: long-term experience of a single institution. Int J Radiat Oncol Biol Phys 68:858–863PubMedCrossRef

13.

Morin O, Gillis A, Descovich M et al (2007) Patient dose considerations for routine megavoltage cone-beam CT imaging. Med Phys 34:1819–1827PubMedCrossRef

14.

Peng LC, Yang CC, Sim S et al (2006) Dose comparison of megavoltage cone-beam and orthogonal-pair portal images. J Appl Clin Med Phys 8:10–20PubMedCrossRef

15.

Peponi E, Glanzmann C, Kunz G et al (2010) Simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) in nasopharyngeal cancer. Strahlenther Onkol 186:135–142PubMedCrossRef

16.

Pinkawa M, Holy R, Piroth MD et al (2010) Intensity-modulated radiotherapy for prostate cancer implementing molecular imaging with 18 F-choline PET-CT to define a simultaneous integrated boost. Strahlenther Onkol 186:600–606PubMedCrossRef

17.

Preiser K, Bortfeld T, Hartwig K et al (1998) Inverse radiotherapy planning for intensity modulated photon fields. Radiologe 38:228–234. ReviewPubMedCrossRef

18.

Radiotherapy equipment – Coordinates, movements and scales. IEC 61217:1996–2008

19.

Schlegel W, Pastyr O, Bortfeld T et al (1992) Computer systems and mechanical tools for stereotactically guided conformation therapy with linear accelerators. Int J Radiat Oncol Biol Phys 24:781–787PubMedCrossRef

20.

Stützel J, Oelfke U, Nill S (2008) A quantitive image quality comparison of four different image guided therapy devices. Radiother Oncol 86:20–24PubMedCrossRef

21.

Wiezorek T, Schwahofer A, Schubert K (2009) The influence of different IMRT. Techniques on the peripheral dose. Strahlenther Onkol 185:696–702PubMedCrossRef

22.

Zabel A, Milker-Zabel S, Huber P et al (2004) Fractionated stereotactic conformal radiotherapy in the management of large chemodectomas of the skull base. Int J Radiat Oncol Biol Phys 58:1445–1450PubMedCrossRef

23.

Zwicker F, Hauswald H, Nill S, Rhein B et al (2010) New multileaf collimator with a leaf width of 5 mm improves plan quality compared to 10 mm in step-and-shoot IMRT of HNC using integrated boost procedure. Strahlenther Onkol 186:334–343PubMedCrossRef

Titel: Dosimetric integration of daily mega-voltage cone-beam CT for image-guided intensity-modulated radiotherapy
verfasst von: PD Dr. A. Zabel-du Bois
S. Nill
S. Ulrich
U. Oelfke
B. Rhein
P. Haering
S. Milker-Zabel
A. Schwahofer
Publikationsdatum: 01.02.2012
Verlag: Springer Berlin Heidelberg
Erschienen in: Strahlentherapie und Onkologie / Ausgabe 2/2012
Print ISSN: 0179-7158
Elektronische ISSN: 1439-099X
DOI: https://doi.org/10.1007/s00066-011-0021-z

Springer Medizin

Dosimetric integration of daily mega-voltage cone-beam CT for image-guided intensity-modulated radiotherapy