Conformal treatment planning using 4DCT can decrease ipsilateral lung dose and improve tumor coverage: A prospective 4DCT treatment planning study

Parikh, Parag J.; Wahab, Sasha H.; Lu, Wenfu; Nantz, Regan; Hubenschmidt, J; Nystrom, M.; El-Naqa, I.; Pierburg, B.; Bradley, Jeffrey D.; Low, D

doi:10.1016/s0360-3016(04)01351-3

Cited by 1 publication

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“…The 4D data measured with this technique has been used to quantify breathing motion for conformal therapy treatment planning, 25,26 however, the motion data are novel and when fully automated deformable registration algorithms are developed, these techniques may be used to measure other functional characteristics of breathing, such as airflow and flexibility of the lung tissues. These data may be valuable for areas of medicine other than radiation oncology.…”

Section: Discussionmentioning

confidence: 99%

“…These data sets can be used to track tumor and lung tissue motion during breathing 23,24 or to determine the extent of tumor motion for margin selection in the treatment planning process. 25,26 The aim of this work is to quantify the reconstructed 4D CT data set quality by correlating spirometry to internal-object motion. Strong correlations imply that the spirometry has a close relationship with internal object motion, specifically, with tumor motion.…”

Section: Introductionmentioning

confidence: 99%

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Quantitation of the reconstruction quality of a four‐dimensional computed tomography process for lung cancer patients

Parikh

Naqa

et al. 2005

Medical Physics

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We have developed a four-dimensional computed tomography (4D CT) technique for mapping breathing motion in radiotherapy treatment planning. A multislice CT scanner (1.5 mm slices) operated in ciné mode was used to acquire 12 contiguous slices in each couch position for 15 consecutive scans (0.5 s rotation, 0.25 s between scans) while the patient underwent simultaneous quantitative spirometry measurements to provide a sorting metric. The spirometry-sorted scans were used to reconstruct a 4D data set. A critical factor for 4D CT is quantifying the reconstructed data set quality which we measure by correlating the metric used relative to internal-object motion. For this study, the internal air content within the lung was used as a surrogate for internal motion measurements. Thresholding and image morphological operations were applied to delineate the air-containing tissues (lungs, trachea) from each CT slice. The Hounsfield values were converted to the internal air content (V). The relationship between the air content and spirometer-measured tidal volume (v) was found to be quite linear throughout the lungs and was used to estimate the overall accuracy and precision of tidal volume-sorted 4D CT. Inspection of the CT-scan air content as a function of tidal volume showed excellent correlations (typically r>0.99) throughout the lung volume. Because of the discovered linear relationship, the ratio of internal air content to tidal volume was indicative of the fraction of air change in each couch position. Theoretically, due to air density differences within the lung and in room, the sum of these ratios would equal 1.11. For 12 patients, the mean value was 1.08 +/- 0.06, indicating the high quality of spirometry-based image sorting. The residual of a first-order fit between v and V was used to estimate the process precision. For all patients, the precision was better than 8%, with a mean value of 5.1% +/- 1.9%. This quantitative analysis highlights the value of using spirometry as the metric in sorting CT scans. The 4D reconstruction provides the CT data required to measure the three-dimensional trajectory of tumor and lung tissue during free breathing.

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Section: Discussionmentioning

confidence: 99%