Integration of magnetic resonance imaging into radiation therapy treatment planning: i. technical considerations

Fraass, Benedick A.; McShan, Daniel L.; Diaz, Richard; Haken, Randall K. Ten; Aisen, Alex M.; Gebarśki, Stephen S.; Glazer, Gary M.; Lichter, Allen S.

doi:10.1016/0360-3016(87)90358-0

Cited by 108 publications

(44 citation statements)

References 9 publications

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“…[17][18][19] MRI also suffers poorer geometric accuracy of the patient contour and lack of electron density information. 20,21 In the face of pros and cons for the two imaging techniques, we did not intend to adopt CT as a complement to MRI in delineating tumor volume. A technique for MRI-derived tumor volume assessment was not available in Taiwan when this study was conducted.…”

Section: Limitations and Future Directions Of Studymentioning

confidence: 99%

Better prediction of prognosis for patients with nasopharyngeal carcinoma using primary tumor volume

Chen

Liu

et al. 2004

Cancer

114

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BACKGROUNDHeterogeneity of primary tumor volume within tumors of the same classification indicates a need to elucidate the effects of primary tumor volume on treatment outcomes in patients with nasopharyngeal carcinoma (NPC).METHODSFrom 1994 through 1996, 129 patients with newly diagnosed NPC who were treated with high‐dose radiotherapy were enrolled in the study. Computed tomography‐derived primary tumor volume was measured using the summation‐of‐area technique. Correlations between American Joint Committee on Cancer (AJCC) disease stage, primary tumor volume, and disease‐specific survival were assessed using a Cox regression model. Cross‐validation based on receiver operating characteristic (ROC) curve also was examined.RESULTSCompared with the AJCC staging system and the TNM classification system, primary tumor volume was better at determining cumulative survival for patients with NPC. Hazard ratios increased with tumor volume, ranging from 6.68 (95% confidence interval [95% CI], 1.89–23.67) for tumor volumes between 20–40 mL, 18.03 (95% CI, 4.80–67.75) for tumor volumes between 40–60 mL, and 26.06 (95% CI, 7.70–88.20) for tumor volumes > 60 mL. With both tumor volume and T classification in the same Cox regression model, only tumor volume remained statistically significant in the prognosis of NPC. The validation results with ROC curves also revealed that, in predicting patient outcome, primary tumor volume (area under the ROC = 83.33%) was superior to disease stage (area under the ROC = 66.53%) and TNM classification (area under the ROC = 58.61%).CONCLUSIONSThe incorporation of primary tumor volume may lead to a further refinement of the current AJCC staging system, particularly for patients with large primary tumor volumes (> 60 mL), who require more aggressive treatment. Cancer 2004. © 2004 American Cancer Society.

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Section: Limitations and Future Directions Of Studymentioning

confidence: 99%

Better prediction of prognosis for patients with nasopharyngeal carcinoma using primary tumor volume

Chen

Liu

et al. 2004

Cancer

114

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“…A di erent approach is the use of both CT and MRI. These methods rely on CT for geometric accuracy and on MRI for tumour visualization Van den Elsen 1993;Fraass et al 1987;Kessler et al 1991;Kooy et al 1994;Pelizzari et al 1989;Schad et al 1987b. This approach requires matching of both datasets, which theoretically can be better accomplished if MR image distortions have been reduced by pulse sequence optimization or if the distortions have been corrected.…”

Section: Correction Methodsmentioning

confidence: 99%

“…Also in MR body imaging, for which larger elds of view are necessary, the distortions will be larger compared to distortions in head imaging. Fraass et al 1987 concluded that a full 3D unwarping algorithm was mandatory to achieve geometrical consistency and also Schad et al 1987a reduced in-plane distortions from 5 mm to 1-2 mm and corrected tilt of the image planes by adjustment of the gradient shimming currents. Apart from marker based image registration Van den Elsen and Viergever 1994;Sumanaweera et al 1994, a variety of techniques is available to register image sets from di erent modalities based on features of the objects to be imaged Van den Elsen et al 1993;Maurer and Fitzpatrick 1993.…”

Section: Integration Of Mri Into Rtpmentioning

confidence: 99%

“…Imaging techniques like 3D-CT and 3D-MRI are being evaluated as to their potential for radiotherapy treatment planning Fraass et al 1987;Glatstein et al 1985;Schad et al 1987b;TenHaken et al 1992;Heesters et al 1993. The application of these imaging techniques allows optimization of treatment plans to cover the target volumes as close as possible, often called conformation therapy Vijayakumar and Chen 1995.…”

Section: Mri Organ Motion Studies For Rtpmentioning

confidence: 99%

“…New imaging techniques like 3D-CT and 3D-MRI are now being evaluated on their potential for radiotherapy treatment planning Bhagwandien et al 1992a;Ende et al 1992;Fraass et al 1987;Glatstein et al 1985;Schad et al 1987a;Schad et al 1987b;Shuman et al 1985;TenHaken et al 1992;Thornton et al 1992;Toonkel et al 1988. The application of these imaging techniques allows optimization of treatment plans by the use of non-coplanar beam settings and conformation therapy Boesecke et al 1991;Brahme 1988.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic resonance imaging in radiotherapy treatment planning

Moerland¹

1997

Medical Physics

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The aim of this study is to investigate the capabilities of magnetic resonance imaging (MRI) in radiotherapy treatment planning (RTP) and to explore the MR image distortions and how these distortions can be reduced or, if necessary, corrected in order to integrate MRI into RTP in a reliable manner. Image distortions and the efficacy of correction methods were evaluated in phantom, volunteer, and patient studies. From the measurement, analysis, and correction of machine‐related geometric distortions in MRI, it was concluded that MR image corrections are necessary in applications which require mm accuracy and that correction methods, based on 3D maps of static field inhomogeneity and gradient nonlinearity, are feasible in clinical practice. From the measurement and numerical analysis of object‐related geometric distortions, it was concluded that these distortions can be reduced to the order of the pixel size by imaging at 0.5 T and using gradients on the order of 3 mT normalm−1. Furthermore, in a study on volunteers, fast MRI scan techniques were used to measure the respiration induced kidney movement and in a study on patients with prostate cancer, the value of MRI for the evaluation of brachytherapy was demonstrated. The MR image artifacts induced by the I‐125 seeds were used to evaluate the dose distributions and dose volume histograms of permanent prostate implants.

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Effect of distortions and asymmetry in MR images on radiotherapeutic treatment planning

et al. 2000

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Before using MR‐images for radiotherapeutic treatment planning, it is necessary to check whether geometrical distortions influence the calculated dose distribution. In this study, 27 MRI units from different manufacturers and with different magnetic field strengths were investigated. First, all geometrical distortions and asymmetry were determined by specially defined parameters. Virtual planning target volume and organ of risk were drawn into MR images from different units and optimized dose distributions were calculated. The resulting field parameters were then transferred to the reference geometry. Geometric distortions caused small variations of the dose maximum (±0.5%). Twenty‐five percent of the investigated calculated dose distributions showed an increase of the 95% isodose volume, 60% a decrease. The dose deviations in the organ of risk were comparable with the dose deviations in the planning target volume (PTV). This study has shown that measurements of geometrical distortions and asymmetry are necessary for MR‐assisted treatment planning. For evaluation, we recommend dose calculations with hypothetical PTV's and organs of risk. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 46–50 (2000). © 2000 Wiley‐Liss, Inc.

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Integration of magnetic resonance imaging into radiation therapy treatment planning: i. technical considerations

Cited by 108 publications

References 9 publications

Better prediction of prognosis for patients with nasopharyngeal carcinoma using primary tumor volume

Better prediction of prognosis for patients with nasopharyngeal carcinoma using primary tumor volume

Magnetic resonance imaging in radiotherapy treatment planning

Effect of distortions and asymmetry in MR images on radiotherapeutic treatment planning

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