Dose-volume and biological-model based comparison between helical tomotherapy and (inverse-planned) IMAT for prostate tumours.

BACKGROUND AND PURPOSE Helical tomotherapy (HT) and intensity-modulated arc therapy (IMAT) are two arc-based approaches to the delivery of intensity-modulated radiotherapy (IMRT). Through plan comparisons we have investigated the potential of IMAT, both with constant (conventional or IMAT-C) and variable (non-conventional or IMAT-NC, a theoretical exercise) dose-rate, to serve as an alternative to helical tomotherapy. MATERIALS AND METHODS Six patients with prostate tumours treated by HT with a moderately hypo-fractionated protocol, involving a simultaneous integrated boost, were re-planned as IMAT treatments. A method for IMAT inverse-planning using a commercial module for static IMRT combined with a multi-leaf collimator (MLC) arc-sequencing was developed. IMAT plans were compared to HT plans in terms of dose statistics and radiobiological indices. RESULTS Concerning the planning target volume (PTV), the mean doses for all PTVs were similar for HT and IMAT-C plans with minimum dose, target coverage, equivalent uniform dose (EUD) and tumour control probability (TCP) values being generally higher for HT; maximum dose and degree of heterogeneity were instead higher for IMAT-C. In relation to organs at risk, mean doses and normal tissue complication probability (NTCP) values were similar between the two modalities, except for the penile bulb where IMAT was significantly better. Re-normalizing all plans to the same rectal toxicity (NTCP=5%), the HT modality yielded higher TCP than IMAT-C but there was no significant difference between HT and IMAT-NC. The integral dose with HT was higher than that for IMAT. CONCLUSIONS with regards to the plan analysis, the HT is superior to IMAT-C in terms of target coverage and dose homogeneity within the PTV. Introducing dose-rate variation during arc-rotation, not deliverable with current linac technology, the simulations result in comparable plan indices between (IMAT-NC) and HT.

[1]  Daliang Cao,et al.  Comparison of plan quality provided by intensity-modulated arc therapy and helical tomotherapy. , 2007, International journal of radiation oncology, biology, physics.

[2]  A. Nahum,et al.  Biological Evaluation of Treatment Plans , 2007 .

[3]  M. Mackenzie,et al.  Intensity modulated arc deliveries approximated by a large number of fixed gantry position sliding window dynamic multileaf collimator fields. , 2002, Medical physics.

[4]  A. Niemierko.  Reporting and analyzing dose distributions: a concept of equivalent uniform dose. , 1997, Medical physics.

[5]  Eugene Wong,et al.  Segmentation and leaf sequencing for intensity modulated arc therapy. , 2007, Medical Physics (Lancaster).

[6]  Chengyu Shi,et al.  Treatment plan comparison between helical tomotherapy and MLC-based IMRT using radiobiological measures , 2007, Physics in medicine and biology.

[7]  Michael Lock,et al.  Comparing two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the hypofractionated treatment of high-risk prostate cancer , 2008, Radiation oncology.

[8]  D P Dearnaley,et al.  Individualization of dose prescription based on normal-tissue dose-volume and radiosensitivity data. , 2001, International journal of radiation oncology, biology, physics.

[9]  Riccardo Calandrino,et al.  Results of a two-year quality control program for a helical tomotherapy unit. , 2008, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[10]  David A Jaffray,et al.  Intensity-modulated arc therapy with dynamic multileaf collimation : an alternative to tomotherapy , 2002 .

[11]  David J Brenner,et al.  Solid tumor risks after high doses of ionizing radiation. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[12]  B Sanchez-Nieto,et al.  BIOPLAN: software for the biological evaluation of. Radiotherapy treatment plans. , 2000, Medical dosimetry : official journal of the American Association of Medical Dosimetrists.

[13]  Cedric X. Yu,et al.  Clinical implementation of intensity-modulated arc therapy. , 2002, International journal of radiation oncology, biology, physics.

[14]  A. Nahum,et al.  Tumour control probability modelling: Basic principles and applications in treatment planning. , 2001 .

[15]  E. Hall,et al.  Radiation-induced second cancers: the impact of 3D-CRT and IMRT. , 2003, International journal of radiation oncology, biology, physics.

[16]  F Foppiano,et al.  Fitting late rectal bleeding data using different NTCP models: results from an Italian multi-centric study (AIROPROS0101). , 2004, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[17]  Di Yan,et al.  Phase II dose escalation study of image-guided adaptive radiotherapy for prostate cancer: use of dose-volume constraints to achieve rectal isotoxicity. , 2005, International journal of radiation oncology, biology, physics.

[18]  W. Tomé,et al.  Pelvic nodal dose escalation with prostate hypofractionation using conformal avoidance defined (H-CAD) intensity modulated radiation therapy. , 2005, Acta oncologica.

[19]  Dosimetric, mechanical, and geometric verification of conformal dynamic arc treatment , 2003, Journal of applied clinical medical physics.

[20]  M A Earl,et al.  An arc-sequencing algorithm for intensity modulated arc therapy. , 2007, Medical physics.

[21]  Timothy E Schultheiss,et al.  Dosimetric comparisons of helical tomotherapy treatment plans and step-and-shoot intensity-modulated radiosurgery treatment plans in intracranial stereotactic radiosurgery. , 2006, International journal of radiation oncology, biology, physics.

[22]  F. Fazio,et al.  Significant reduction of acute toxicity following pelvic irradiation with helical tomotherapy in patients with localized prostate cancer. , 2007, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[23]  Ke Sheng,et al.  Intensity-modulated radiation therapy (IMRT) dosimetry of the head and neck: a comparison of treatment plans using linear accelerator-based IMRT and helical tomotherapy. , 2006, International journal of radiation oncology, biology, physics.

[24]  E. Wong,et al.  Planning evaluation of radiotherapy for complex lung cancer cases using helical tomotherapy. , 2004, Physics in medicine and biology.

[25]  J. Conway,et al.  Clinical implications of the anisotropic analytical algorithm for IMRT treatment planning and verification. , 2008, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[26]  Riccardo Calandrino,et al.  Simultaneous Integrated Boost (SIB) for Nasopharynx Cancer with Helical Tomotherapy , 2007, Strahlentherapie und Onkologie.

[27]  L. Incrocci,et al.  Erectile dysfunction after radiotherapy for prostate cancer and radiation dose to the penile structures: a critical review. , 2007, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[28]  Yi-Jen Chen,et al.  Dosimetric comparison of helical tomotherapy treatment and step-and-shoot intensity-modulated radiotherapy of retroperitoneal sarcoma. , 2006, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[29]  Tomas Kron,et al.  A comparison of prostate IMRT and helical tomotherapy class solutions. , 2006, Radiotherapy and Oncology.

[30]  Chengyu Shi,et al.  Dosimetric comparison of Helical Tomotherapy and Gamma Knife Stereotactic Radiosurgery for single brain metastasis , 2006, Radiation oncology.

[31]  Cedric X. Yu,et al.  New Developments in Intensity Modulated Radiation Therapy , 2006, Technology in cancer research & treatment.

[32]  Mauro Iori,et al.  Testing of the analytical anisotropic algorithm for photon dose calculation. , 2006, Medical physics.

[33]  M. Goitein,et al.  Tolerance of normal tissue to therapeutic irradiation. , 1991, International journal of radiation oncology, biology, physics.

[34]  Yi-Jen Chen,et al.  Helical tomotherapy for radiotherapy in esophageal cancer: a preferred plan with better conformal target coverage and more homogeneous dose distribution. , 2007, Medical dosimetry : official journal of the American Association of Medical Dosimetrists.

[35]  S. Cora,et al.  Comparison of advanced irradiation techniques with photons for benign intracranial tumours. , 2006, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[36]  A. Nahum,et al.  Incorporating clinical measurements of hypoxia into tumor local control modeling of prostate cancer: implications for the alpha/beta ratio. , 2003, International journal of radiation oncology, biology, physics.

[37]  A. Nahum,et al.  Incorporating clinical measurements of hypoxia into tumor local control modeling of prostate cancer: Implications for the α/β ratio , 2003 .

[38]  T R Mackie,et al.  History of tomotherapy , 2006, Physics in medicine and biology.

[39]  Luca Cozzi,et al.  Comparison of dose calculation algorithms for treatment planning in external photon beam therapy for clinical situations , 2006, Physics in medicine and biology.

[40]  Barbara Kaser-Hotz,et al.  The impact of dose escalation on secondary cancer risk after radiotherapy of prostate cancer. , 2007, International journal of radiation oncology, biology, physics.

[41]  C. Yu,et al.  Inverse planning for intensity-modulated arc therapy using direct aperture optimization. , 2001, Physics in Medicine and Biology.

[42]  D. Huyskens,et al.  On-line quality assurance of rotational radiotherapy treatment delivery by means of a 2D ion chamber array and the Octavius phantom. , 2007, Medical physics.