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. 2013 Jun;31(2):104-10.
doi: 10.3857/roj.2013.31.2.104. Epub 2013 Jun 30.

Comparison study of intensity modulated arc therapy using single or multiple arcs to intensity modulated radiation therapy for high-risk prostate cancer

Hani Ashamalla  1 , Ajay Tejwani, Ioannis Parameritis, Uma Swamy, Pei Ching Luo, Adel Guirguis, Amir Lavaf
Affiliations

Comparison study of intensity modulated arc therapy using single or multiple arcs to intensity modulated radiation therapy for high-risk prostate cancer

Hani Ashamalla et al. Radiat Oncol J. 2013 Jun.

Abstract

Purpose: Intensity modulated arc therapy (IMAT) is a form of intensity modulated radiation therapy (IMRT) that delivers dose in single or multiple arcs. We compared IMRT plans versus single-arc field (1ARC) and multi-arc fields (3ARC) IMAT plans in high-risk prostate cancer.

Materials and methods: Sixteen patients were studied. Prostate (PTV P ), right pelvic (PTV RtLN ) and left pelvic lymph nodes (PTV LtLN ), and organs at risk were contoured. PTV P , PTV RtLN , and PTV LtLN received 50.40 Gy followed by a boost to PTV B of 28.80 Gy. Three plans were per patient generated: IMRT, 1ARC, and 3ARC. We recorded the dose to the PTV, the mean dose (D MEAN ) to the organs at risk, and volume covered by the 50% isodose. Efficiency was evaluated by monitor units (MU) and beam on time (BOT). Conformity index (CI), Paddick gradient index, and homogeneity index (HI) were also calculated.

Results: Average Radiation Therapy Oncology Group CI was 1.17, 1.20, and 1.15 for IMRT, 1ARC, and 3ARC, respectively. The plans' HI were within 1% of each other. The D MEAN of bladder was within 2% of each other. The rectum D MEAN in IMRT plans was 10% lower dose than the arc plans (p < 0.0001). The GI of the 3ARC was superior to IMRT by 27.4% (p = 0.006). The average MU was highest in the IMRT plans (1686) versus 1ARC (575) versus 3ARC (1079). The average BOT was 6 minutes for IMRT compared to 1.3 and 2.9 for 1ARC and 3ARC IMAT (p < 0.05).

Conclusion: For high-risk prostate cancer, IMAT may offer a favorable dose gradient profile, conformity, MU and BOT compared to IMRT.

Keywords: High risk prostate cancer; Intensity modulated arc therapy; Intensity modulated radiation therapy; RapidArc.

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Conflict of interest statement

No potential conflict of interest relevant to this article was reported.

Figures

Fig. 1
Fig. 1
Field arrangement and dose distribution for V50 ≤ dose ≤ VMax.
Fig. 2
Fig. 2
(A) Average "Beam On" time in minutes and (B) average number of monitor units (MU). IMRT, intensity modulated radiation therapy.
Fig. 3
Fig. 3
Average DMEAN of rectum and bladder. IMRT, intensity modulated radiation therapy.
Fig. 4
Fig. 4
Average integral dose (V50). IMRT, intensity modulated radiation therapy.
Fig. 5
Fig. 5
Average conformity index. IMRT, intensity modulated radiation therapy.
Fig. 6
Fig. 6
Average gradient index. IMRT, intensity modulated radiation therapy.
Fig. 7
Fig. 7
Average homogeneity Index. IMRT, intensity modulated radiation therapy.
See this image and copyright information in PMC

References

    1. Viani GA, Stefano EJ, Afonso SL. Higher-than-conventional radiation doses in localized prostate cancer treatment: a meta-analysis of randomized, controlled trials. Int J Radiat Oncol Biol Phys. 2009;74:1405–1418. - PubMed
    1. Lawton CA, DeSilvio M, Roach M, 3rd, et al. An update of the phase III trial comparing whole pelvic to prostate only radiotherapy and neoadjuvant to adjuvant total androgen suppression: updated analysis of RTOG 94-13, with emphasis on unexpected hormone/radiation interactions. Int J Radiat Oncol Biol Phys. 2007;69:646–655. - PMC - PubMed
    1. Zelefsky MJ, Fuks Z, Happersett L, et al. Clinical experience with intensity modulated radiation therapy (IMRT) in prostate cancer. Radiother Oncol. 2000;55:241–249. - PubMed
    1. Marks LB, Yorke ED, Jackson A, et al. Use of normal tissue complication probability models in the clinic. Int J Radiat Oncol Biol Phys. 2010;76(3 Suppl):S10–S19. - PMC - PubMed
    1. Radiation Therapy Oncology Group. RTOG Clinical Trials [Internet] Philadelphia, PA: RTOG; c2013. [cited 2013 May 23]. Available from: http://www.rtog.org/ClinicalTrials/ProtocolTable.aspx.

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