A technique for adaptive image-guided helical tomotherapy for lung cancer

Ramsey, C; Langen, K; Kupelian, Patrick A.; Scaperoth, D.; Meeks, Sanford L.; Mahan, S; Seibert, R.

doi:10.1016/j.ijrobp.2005.11.012

Cited by 114 publications

(63 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[7][8][9][10] These works implement various replanning schedules ranging from single to weekly adaptations and demonstrate a patient-specific benefit for adaptive plans in the context of tumor regression. While a variety of schedules have been implemented by the respective authors, systematic comparisons between schedules of the varying adaptive frequency have not been performed; furthermore, the nature of tradeoff between the replanning frequency and adaptive benefit is not understood.…”

Section: Introductionmentioning

confidence: 99%

Benefits of adaptive radiation therapy in lung cancer as a function of replanning frequency

et al. 2016

View full text Add to dashboard Cite

Purpose: To quantify the potential benefit associated with daily replanning in lung cancer in terms of normal tissue dose sparing and to characterize the tradeoff between adaptive benefit and replanning frequency. Methods: A set of synthetic images and contours, derived from weekly active breathing control images of 12 patients who underwent radiation therapy treatment for nonsmall cell lung cancer, is generated for each fraction of treatment using principal component analysis in a way that preserves temporal anatomical trends (e.g., tumor regression). Daily synthetic images and contours are used to simulate four different treatment scenarios: (1) a "no-adapt" scenario that simulates delivery of an initial plan throughout treatment, (2) a "midadapt" scenario that implements a single replan for fraction 18, (3) a "weekly adapt" scenario that simulates weekly adaptations, and (4) a "full-adapt" scenario that simulates daily replanning. An initial intensity modulated radiation therapy plan is created for each patient and replanning is carried out in an automated fashion by reoptimizing beam apertures and weights. Dose is calculated on each image and accumulated to the first in the series using deformable mappings utilized in synthetic image creation for comparison between simulated treatments. Results: Target coverage was maintained and cord tolerance was not exceeded for any of the adaptive simulations. Average reductions in mean lung dose (MLD) and volume of lung receiving 20 Gy or more (V 20 lung ) were 65 ± 49 cGy (p = 0.000 01) and 1.1% ± 1.2% (p = 0.0006), respectively, for all patients. The largest reduction in MLD for a single patient was 162 cGy, which allowed an isotoxic escalation of the target dose of 1668 cGy. Average reductions in cord max dose, mean esophageal dose (MED), dose received by 66% of the heart (D66 heart ), and dose received by 33% of the heart (D33 heart ), were 158 ± 280, 117 ± 121, 37 ± 77, and 99 ± 120 cGy, respectively. Average incremental reductions in MLD for the midadapt, weekly adapt, and full-adapt treatments were 38, 18, and 8 cGy, respectively. Incremental reductions in MED for the same treatments were 57, 37, and 23 cGy. Reductions in MLD and MED for the full-adapt treatment were correlated with the absolute decrease in the planning target volume (r = 0.34 and r = 0.26). Conclusions: Adaptive radiation therapy for lung cancer yields clinically relevant reductions in normal tissue doses for frequencies of adaptation ranging from a single replan up to daily replanning. Increased frequencies of adaptation result in additional benefit while magnitude of benefit decreases. C 2016 American Association of Physicists in Medicine. [http://dx

show abstract

Section: Introductionmentioning

confidence: 99%

Benefits of adaptive radiation therapy in lung cancer as a function of replanning frequency

et al. 2016

View full text Add to dashboard Cite

show abstract

“…However, there is considerable interest in the use of CBCT images for the purposes of adaptive radiation therapy (ART). Studies have looked at the process of ART for several disease sites: prostate, [9][10][11] head and neck, [12][13][14] lung, 15,16 and so on. For each site, the use of CBCT images involves some advantages and difficulties.…”

Section: Introductionmentioning

confidence: 99%

Investigation into image quality and dose for different patient geometries with multiple cone‐beam CT systems

et al. 2014

View full text Add to dashboard Cite

Purpose:To provide quantitative and qualitative image quality metrics and imaging dose for modern Varian On-board Imager (OBI) (ver. 1.5) and Elekta X-ray Volume Imager (XVI) (ver. 4.5R) conebeam computed tomography (CBCT) systems in a clinical adaptive radiation therapy environment by accounting for varying patient thickness. Methods: Image quality measurements were acquired with Catphan 504 phantom (nominal diameter and with additional 10 cm thickness) for OBI and XVI systems and compared to planning CT (pCT) (GE LightSpeed). Various clinical protocols were analyzed for the OBI and XVI systems and analyzed using image quality metrics, including spatial resolution, low contrast detectability, uniformity, and HU sensitivity. Imaging dose measurements were acquired in Wellhofer Scanditronix i'mRT phantom at nominal phantom diameter and with additional 4 cm phantom diameter using GafChromic XRQA2 film. Calibration curves were generated using previously published in-air Air Kerma calibration method. Results: The OBI system full trajectory scans exhibited very little dependence on phantom thickness for accurate HU calculation, while half-trajectory scans with full-fan filter exhibited dependence of HU calculation on phantom thickness. The contrast-to-noise ratio (CNR) for the OBI scans decreased with additional phantom thickness. The uniformity of Head protocol scan was most significantly affected with additional phantom thickness. The spatial resolution and CNR compared favorably with pCT, while the uniformity of the OBI system was slightly inferior to pCT. The OBI scan protocol dose levels for nominal phantom thickness at the central portion of the phantom were 2.61, 0.72, and 1.88 cGy, and for additional phantom thickness were 1.95, 0.48, and 1.52 cGy, for the Pelvis, Thorax, and Spotlight protocols, respectively. The XVI system scans exhibited dependence on phantom thickness for accurate HU calculation regardless of trajectory. The CNR for the XVI scans decreased with additional phantom thickness. The uniformity of the XVI scans was significantly dependent on the selection of the proper FOV setting for all phantom geometries. The spatial resolution, CNR, and uniformity for XVI were lower than values measured for pCT. The XVI scan protocol dose levels at the central portion of the phantom for nominal phantom thickness were 2.14, 2.15, and 0.33 cGy, and for additional phantom thickness were 1.56, 1.68, and 0.21 cGy, for the Pelvis M20, Chest M20, and Prostate Seed S10 scan protocols, respectively. Conclusions: The OBI system offered comparable spatial resolution and CNR results to the results for pCT. Full trajectory scans with the OBI system need little-to-no correction for HU calculation based on HU stability with changing phantom thickness. The XVI system offered lower spatial resolution and CNR results than pCT. In addition, the HU calculation for all scan protocols was dependent on the phantom thickness. The uniformity for each CBCT system was inferior to that of pCT for each phantom geometry. The dose for ea...

show abstract

“…Generally, NSCLC tumor response to radiotherapy is believed to be a slow process because tumors reach their maximum response (minimum volume) an average of 11 months after radiotherapy completion (9). Kupelian et al (10) and Siker et al (11) used measurements of tumor volume on serial MVCT image sets generated by helical tomotherapy to document interfractional radiation responses during a shorter period, whereas Ramsey et al (12) focused on adaptive dosimetric planning as tumor volume changes. Others used multiple kVCT scans to evaluate tumor volume changes during radiotherapy (13)(14)(15)(16) or portal images to monitor tumor position, size, and movement (17).…”

Section: Introductionmentioning

confidence: 99%

Adaptive Radiotherapy Planning on Decreasing Gross Tumor Volumes as Seen on Megavoltage Computed Tomography Images

Woodford

Yartsev

Dar

et al. 2007

International Journal of Radiation Oncology*Biology*Physics

159

155

View full text Add to dashboard Cite

Purpose: To evaluate gross tumor volume (GTV) changes for patients with non-small-cell lung cancer by using daily megavoltage (MV) computed tomography (CT) studies acquired before each treatment fraction on helical tomotherapy and to relate the potential benefit of adaptive image-guided radiotherapy to changes in GTV. Methods and Materials: Seventeen patients were prescribed 30 fractions of radiotherapy on helical tomotherapy for non-small-cell lung cancer at London Regional Cancer Program from Dec 2005 to March 2007. The GTV was contoured on the daily MVCT studies of each patient. Adapted plans were created using merged MVCT-kilovoltage CT image sets to investigate the advantages of replanning for patients with differing GTV regression characteristics.Results: Average GTV change observed over 30 fractions was À38%, ranging from À12 to À87%. No significant correlation was observed between GTV change and patient's physical or tumor features. Patterns of GTV changes in the 17 patients could be divided broadly into three groups with distinctive potential for benefit from adaptive planning. Conclusions: Changes in GTV are difficult to predict quantitatively based on patient or tumor characteristics. If changes occur, there are points in time during the treatment course when it may be appropriate to adapt the plan to improve sparing of normal tissues. If GTV decreases by greater than 30% at any point in the first 20 fractions of treatment, adaptive planning is appropriate to further improve the therapeutic ratio. Ó 2007 Elsevier Inc.

show abstract

A technique for adaptive image-guided helical tomotherapy for lung cancer

Cited by 114 publications

References 29 publications

Benefits of adaptive radiation therapy in lung cancer as a function of replanning frequency

Benefits of adaptive radiation therapy in lung cancer as a function of replanning frequency

Investigation into image quality and dose for different patient geometries with multiple cone‐beam CT systems

Adaptive Radiotherapy Planning on Decreasing Gross Tumor Volumes as Seen on Megavoltage Computed Tomography Images

Contact Info

Product

Resources

About