Impact of Computed Tomography Image Quality on Image-Guided Radiation Therapy Based on Soft Tissue Registration

Morrow, Natalya; Lawton, Colleen A.; Qi, Xinyue; Li, X. Allen

doi:10.1016/j.ijrobp.2011.11.043

Cited by 49 publications

(49 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…that might affect the setup errors and the CTV-to-PTV margins in the MVCBCT group; no statistical differences were found between the sex, age, weight, and tumor location subgroups. Our result is in agreement with that of Morrow et al (15), in which superior image quality resulted in better reproducibility of soft tissue-based registration for IGRT of the prostate. The margin calculation is a quantitative measure to illustrate the difference for each IGRT cohort.…”

Section: Discussionsupporting

confidence: 93%

Assessment of Interfraction Patient Setup for Head-and-Neck Cancer Intensity Modulated Radiation Therapy Using Multiple Computed Tomography-Based Image Guidance

Qi¹,

Hu²,

Lee³

et al. 2013

International Journal of Radiation Oncology*Biology*Physics

Self Cite

View full text Add to dashboard Cite

Section: Discussionsupporting

confidence: 93%

Assessment of Interfraction Patient Setup for Head-and-Neck Cancer Intensity Modulated Radiation Therapy Using Multiple Computed Tomography-Based Image Guidance

Qi¹,

Hu²,

Lee³

et al. 2013

International Journal of Radiation Oncology*Biology*Physics

Self Cite

View full text Add to dashboard Cite

“…Several studies have assessed inter‐ and intraobserver variability in soft‐tissue‐based patient positioning . Some studies have investigated the accuracy of soft‐tissue‐based patient positioning with CBCT images compared to patient positioning based on fiducial markers for patients undergoing external beam radiotherapy of the prostate .…”

Section: Introductionmentioning

confidence: 99%

Observer uncertainties of soft tissue‐based patient positioning in IGRT

Hirose

Arimura

Fukunaga

et al. 2020

J Applied Clin Med Phys

View full text Add to dashboard Cite

Purpose There remain uncertainties due to inter‐ and intraobserver variability in soft‐tissue‐based patient positioning even with the use of image‐guided radiation therapy (IGRT). This study aimed to reveal observer uncertainties of soft‐tissue‐based patient positioning on cone‐beam computed tomography (CBCT) images for prostate cancer IGRT. Methods Twenty‐six patients (7–8 fractions/patient, total number of 204 fractions) who underwent IGRT for prostate cancer were selected. Six radiation therapists retrospectively measured prostate cancer location errors (PCLEs) of soft‐tissue‐based patient positioning between planning CT (pCT) and pretreatment CBCT (pre‐CBCT) images after automatic bone‐based registration. Observer uncertainties were evaluated based on residual errors, which denoted the differences between soft‐tissue and reference positioning errors. Reference positioning errors were obtained as PCLEs of contour‐based patient positioning between pCT and pre‐CBCT images. Intraobserver variations were obtained from the difference between the first and second soft‐tissue‐based patient positioning repeated by the same observer for each fraction. Systematic and random errors of inter‐ and intraobserver variations were calculated in anterior–posterior (AP), superior–inferior (SI), and left–right (LR) directions. Finally, clinical target volume (CTV)‐to‐planning target volume (PTV) margins were obtained from systematic and random errors of inter‐ and intraobserver variations in AP, SI, and LR directions. Results Interobserver variations in AP, SI, and LR directions were 0.9, 0.9, and 0.5 mm, respectively, for the systematic error, and 1.8, 2.2, and 1.1 mm, respectively, for random error. Intraobserver variations were <0.2 mm in all directions. CTV‐to‐PTV margins in AP, SI, and LR directions were 3.5, 3.8, and 2.1 mm, respectively. Conclusion Intraobserver variability was sufficiently small and would be negligible. However, uncertainties due to interobserver variability for soft‐tissue‐based patient positioning using CBCT images should be considered in CTV‐to‐PTV margins.

show abstract

“…This suggests PTV reduction should decrease the toxicity. Because of the emergence of new image‐guided radiation therapy (IGRT) techniques, PTV reduction deserves further examination (3) . This is particularly important for stereotactic body radiation therapy (SBRT) (4) as the effect of interfraction dose variation may be greater with fewer fractions (5) …”

Section: Introductionmentioning

confidence: 99%

Using daily diagnostic quality images to validate planning margins for prostate interfractional variations

Vassil

Godley

et al. 2016

J Applied Clin Med Phys

View full text Add to dashboard Cite

The purpose of this study is to use the same diagnostic‐quality verification and planning CTs to validate planning margin account for residual interfractional variations with image‐guided soft tissue alignment of the prostate. For nine prostate cancer patients treated with IMRT to 78 Gy in 39 fractions, daily verification CT‐on‐rails images of the first seven and last seven fractions false(n=126false) were retrospectively selected for this study. On these images, prostate, bladder, and rectum were delineated by the same attending physician. Clinical plans were created with a margin of 8 mm except for 5 mm posteriorly, referred to as 8/5 mm. Three additional plans were created for each patient with the margins of 6/4 mm, 4/2 mm, and 2 mm uniform. These plans were subsequently applied to daily images and radiation doses were recalculated. The isocenters of these plans were placed according to clinical online shifts, which were based on soft tissue alignment to the prostate. Retrospective offline shifts by aligning prostate contours were compared to online shifts. The resultant daily target dose was analyzed using D99, the percentage of the prescription dose received by 99% of CTV. The percent of bladder volume receiving 65 Gy false(normalV65Gyfalse) and rectum normalV70Gy were also analyzed. After interfractional correction, using CTV normalD99>97%% criteria, 8/5 mm, 6/4 mm, 4/2 mm, and 2 mm planning margins met the CTV dose coverage in 95%, 91%, 65%, and 53% of the 126 fractions with online shifts, and 99%, 98%, 85%, and 68% with offline shifts. The rectum normalV70Gy and bladder normalV65Gy were significantly decreased at each level of margin reduction (p<0.05). With daily diagnostic quality imaging‐guidance, the interfractional planning margin may be reduced from 8/5 mm to 6/4 mm. The residual interfractional uncertainties most likely stem from prostate rotation and deformation.PACS number(s): 87.53.‐j

show abstract

Impact of Computed Tomography Image Quality on Image-Guided Radiation Therapy Based on Soft Tissue Registration

Cited by 49 publications

References 17 publications

Assessment of Interfraction Patient Setup for Head-and-Neck Cancer Intensity Modulated Radiation Therapy Using Multiple Computed Tomography-Based Image Guidance

Assessment of Interfraction Patient Setup for Head-and-Neck Cancer Intensity Modulated Radiation Therapy Using Multiple Computed Tomography-Based Image Guidance

Observer uncertainties of soft tissue‐based patient positioning in IGRT

Using daily diagnostic quality images to validate planning margins for prostate interfractional variations

Contact Info

Product

Resources

About