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Interfractional variability in intensity-modulated radiotherapy of prostate cancer with or without thermoplastic pelvic immobilization

Interfraktionelle Variabilität der intensitätsmodulierten Strahlentherapie bei Prostatakrebs mit oder ohne thermoplastische Beckenfixierung

Strahlentherapie und Onkologie Aims and scope Submit manuscript



To determine the variability of patient positioning errors associated with intensity-modulated radiotherapy (IMRT) for prostate cancer and to assess the impact of thermoplastic pelvic immobilization on these errors using kilovoltage (kV) cone-beam computed tomography (CBCT).

Materials and methods

From February 2012 to June 2012, the records of 314 IMRT sessions in 19 patients with prostate cancer, performed with or without immobilization at two different facilities in the Korea University Hospital were analyzed. The kV CBCT images were matched to simulation computed tomography (CT) images to determine the simulation-to-treatment variability. The shifts along the x (lateral)-, y (longitudinal)- and z (vertical)-axes were measured, as was the shift in the three dimensional (3D) vector.


The measured systematic errors in the immobilized group during treatment were 0.46 ± 1.75 mm along the x-axis, − 0.35 ± 3.83 mm along the y-axis, 0.20 ± 2.75 mm along the z-axis and 4.05 ± 3.02 mm in the 3D vector. Those of nonimmobilized group were − 1.45 ± 7.50 mm along the x-axis, 1.89 ± 5.07 mm along the y-axis, 0.28 ± 3.81 mm along the z-axis and 8.90 ± 4.79 mm in the 3D vector. The group immobilized with pelvic thermoplastics showed reduced interfractional variability along the x- and y-axes and in the 3D vector compared to the nonimmobilized group (p < 0.05).


IMRT with thermoplastic pelvic immobilization in patients with prostate cancer appears to be useful in stabilizing interfractional variability during the planned treatment course.



Ziel der Studie war es, die Fehlervariabilität der intensitätsmodulierten Strahlentherapie (IMRT) bei der Patientenpositionierung bei Prostatakrebs zu bestimmen und die Auswirkungen der thermoplastischen Beckenfixierung auf diesen Fehler mit der Kilovolt-(KV-)Cone-Beam-Computertomographie (CBCT) zu beurteilen.

Material und Methoden

Von Februar 2012 bis Juni 2012 wurden die Datensätze von 314 Sitzungen von 19 Patienten mit Prostatakrebs, die mittels IMRT mit oder ohne Immobilisierung an zwei verschiedenen Einrichtungen des Korea University Hospital behandelt wurden, analysiert. Die KV-CBCT-Bilder wurden mit der Simulation der Computertomographie-(CT-)Bilder abgestimmt, um die Variabilität zwischen Simulation und Behandlung zu bestimmen. Es wurden die Verschiebungen entlang der x-(lateral), y-(Längs-), z-Achse (vertikal) und im 3-D-Vektor gemessen


Die gemessenen systematischen Fehler der immobilisierten Gruppe während der Behandlung waren 0,46 ± 1,75 mm entlang der x-Achse, − 0,35 ± 3,83 mm entlang der y-Achse, 0,20 ± 2,75 mm entlang der z-Achse und 4,05 ± 3,02 mm im 3-D-Vektor. Die Fehler der nichtimmobilisierten Gruppe waren − 1,45 ± 7,50 mm entlang der x-, 1,89 ± 5,07 mm entlang der y-, 0,28 ± 3,81 mm entlang der z-Achse und 8,90 ± 4,79 mm im 3-D-Vektor. Im Vergleich zur nichtimmobilisierten Gruppe zeigte die mittels Becken-Thermoplast fixierte Gruppe eine geringere interfraktionelle Variabilität in der x- und y-Achse sowie im 3-D-Vektor (p < 0,05).


Bei Patienten mit Prostatakrebs scheint die IMRT mit thermoplastischer Beckenfixierung bei der Stabilisierung der interfraktionellen Variabilität während der geplanten Behandlung nützlich zu sein.

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  1. Viani GA, Stefano EJ, Afonso SL (2009) Higher-than-conventional radiation doses in localized prostate cancer treatment: a meta-analysis of randomized, controlled trials. Int J Radiat Oncol Biol Phys 74:1405–1418

    Article  PubMed  Google Scholar 

  2. Peeters ST, Heemsbergen WD, Koper PC et al (2006) Dose-response in radiotherapy for localized prostate cancer: results of the dutch multicenter randomized phase iii trial comparing 68 gy of radiotherapy with 78 gy. J Clin Oncol 24:1990–1996

    Article  PubMed  Google Scholar 

  3. Chang JH, Lim Joon D, Lee ST et al (2012) Intensity modulated radiation therapy dose painting for localized prostate cancer using (1)(1)c-choline positron emission tomography scans. Int J Radiat Oncol Biol Phys 83:e691–e696

    Article  PubMed  Google Scholar 

  4. Bhide SA, Nutting CM (2010) Recent advances in radiotherapy. BMC Med 8:25

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  5. Song PY, Washington M, Vaida F et al (1996) A comparison of four patient immobilization devices in the treatment of prostate cancer patients with three dimensional conformal radiotherapy. Int J Radiat Oncol Biol Phys 34:213–219

    Article  CAS  PubMed  Google Scholar 

  6. Rosenthal SA, Roach M 3rd, Goldsmith BJ et al (1993) Immobilization improves the reproducibility of patient positioning during six-field conformal radiation therapy for prostate carcinoma. Int J Radiat Oncol Biol Phys 27:921–926

    Article  CAS  PubMed  Google Scholar 

  7. Malone S, Szanto J, Perry G et al (2000) A prospective comparison of three systems of patient immobilization for prostate radiotherapy. Int J Radiat Oncol Biol Phys 48:657–665

    Article  CAS  PubMed  Google Scholar 

  8. Jaffray DA, Siewerdsen JH (2000) Cone-beam computed tomography with a flat-panel imager: initial performance characterization. Med Phys 27:1311–1323

    Article  CAS  PubMed  Google Scholar 

  9. Peng LC, Yang CC, Sim S et al (2007) Dose comparison of megavoltage cone-beam and orthogonal-pair portal images. J Appl Clin Med Phys 8:10–20

    Google Scholar 

  10. Stutzel J, Oelfke U, Nill S (2008) A quantitative image quality comparison of four different image guided radiotherapy devices. Radiother Oncol 86:20–24

    Article  PubMed  Google Scholar 

  11. Siddiqui F, Shi C, Papanikolaou N et al (2008) Image-guidance protocol comparison: supine and prone set-up accuracy for pelvic radiation therapy. Acta Oncol 47:1344–1350

    Article  PubMed  Google Scholar 

  12. Herk M van (2004) Errors and margins in radiotherapy. Semin Radiat Oncol 14:52–64

    Article  PubMed  Google Scholar 

  13. Stroom JC, Boer HC de, Huizenga H et al (1999) Inclusion of geometrical uncertainties in radiotherapy treatment planning by means of coverage probability. Int J Radiat Oncol Biol Phys 43:905–919

    Article  CAS  PubMed  Google Scholar 

  14. Yoon WS, Yang DS, Lee JA et al (2012) The extent and serial pattern of interfractional variation in patients with whole pelvic irradiation: a study using a kilovoltage orthogonal on-board imager. J Appl Clin Med Phys 13:3636

    PubMed  Google Scholar 

  15. Hanley J, Lumley MA, Mageras GS et al (1997) Measurement of patient positioning errors in three-dimensional conformal radiotherapy of the prostate. Int J Radiat Oncol Biol Phys 37:435–444

    Article  CAS  PubMed  Google Scholar 

  16. Czigner K, Agoston P, Forgacs G et al (2012) Patient positioning variations to reduce dose to normal tissues during 3d conformal radiotherapy for high-risk prostate cancer. Strahlenther Onkol 188:816–822

    Article  CAS  PubMed  Google Scholar 

  17. Ost P, Speleers B, De Meerleer G et al (2011) Volumetric arc therapy and intensity-modulated radiotherapy for primary prostate radiotherapy with simultaneous integrated boost to intraprostatic lesion with 6 and 18 mv: a planning comparison study. Int J Radiat Oncol Biol Phys 79:920–926

    Article  PubMed  Google Scholar 

  18. Giske K, Stoiber EM, Schwarz M et al (2011) Local setup errors in image-guided radiotherapy for head and neck cancer patients immobilized with a custom-made device. Int J Radiat Oncol Biol Phys 80:582–589

    Article  PubMed  Google Scholar 

  19. Piziorska M, Kukolowicz P, Zawadzka A et al (2012) Adaptive off-line protocol for prostate external radiotherapy with cone beam computer tomography. Strahlenther Onkol 188:1003–1039

    Article  CAS  PubMed  Google Scholar 

  20. Boda-Heggemann J, Lohr F, Wenz F et al (2011) Kv cone-beam ct-based igrt: a clinical review. Strahlenther Onkol 187:284–291

    Article  PubMed  Google Scholar 

  21. Perks J, Turnbull H, Liu T et al (2011) Vector analysis of prostate patient setup with image-guided radiation therapy via kv cone beam computed tomography. Int J Radiat Oncol Biol Phys 79:915–919

    Article  PubMed  Google Scholar 

  22. Bylund KC, Bayouth JE, Smith MC et al (2008) Analysis of interfraction prostate motion using megavoltage cone beam computed tomography. Int J Radiat Oncol Biol Phys 72:949–956

    Article  PubMed  Google Scholar 

  23. Shah AP, Kupelian PA, Willoughby TR et al (2011) An evaluation of intrafraction motion of the prostate in the prone and supine positions using electromagnetic tracking. Radiother Oncol 99:37–43

    Article  PubMed  Google Scholar 

  24. Pinkawa M, Pursch-Lee M, Asadpour B et al (2008) Image-guided radiotherapy for prostate cancer. implementation of ultrasound-based prostate localization for the analysis of inter- and intrafraction organ motion. Strahlenther Onkol 184:679–685

    Article  PubMed  Google Scholar 

  25. Greer PB, Dahl K, Ebert MA et al (2008) Comparison of prostate set-up accuracy and margins with off-line bony anatomy corrections and online implanted fiducial-based corrections. J Med Imaging Radiat Oncol 52:511–516

    Article  CAS  PubMed  Google Scholar 

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Compliance with ethical guidelines

Conflict of interest. J. A. Lee, C. Y. Kim, Y. J. Park, W. S. Yoon, N. K. Lee, D. S. Yang state that there are no conflicts of interest.

Consent was obtained from all patients identifiable from images or other information within the manuscript. In the case of underage patients, consent was obtained from a parent or legal guardian

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Correspondence to D.S. Yang M.D., Ph.D..

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Lee, J., Kim, C., Park, Y. et al. Interfractional variability in intensity-modulated radiotherapy of prostate cancer with or without thermoplastic pelvic immobilization. Strahlenther Onkol 190, 94–99 (2014).

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