https://openworks.mdanderson.org/sumexp21/1188/thumbnail.jp

Almodovar Abreu, Lusmeralis

Balter, Peter

Brock, Kristy, PhD

He, Yulun

Liao, Zhongxing

Mohan, Radhe

Pollard-Larkin, Julianne

Titt, Uwe

English

Brock, Kristy K., PhD

OpenWorks @ MD Anderson

A step towards true delivered dose with dose accumulation in radiotherapyLusmeralis Almodóvar Abreu1, Yulun He2, Uwe Titt3, Zhongxing Liao4, Julianne Pollard-Larkin3, Peter Balter3, Radhe Mohan3 and Kristy Brock2Department of Chemistry, University of Puerto Rico- Humacao1Department of Imaging Physics2, Radiation Physics3, Radiation Oncology4,The University of Texas MD Anderson Cancer Center2-4, Houston, TXChetty, I. & Rosu-Bubulac, M. (2019).Seminars in Radiation Oncology. 29(3),198-208.Zhong, H. & Chetty, I. (2017). Physicsin Medicine and Biology. 62(11), 4333-4345.Acknowledgements: This presentation is supported by the National Cancer Institute through the R25 Training Grant: CPRIT-CURE Summer Program. For further information, please contact Lusmeralis Almodóvar Abreu at lusmeralis.almodovar@upr.edu.§ To determine the fractionation scheme and identifytumor regressions of non-small cell lung cancer(NSCLC) patients treated with standard-fractionatedRT using weekly four-dimensional computedtomography (4DCT) images.ConclusionsMethods4DCT Date FractionPlanning week 7/13/2012 30Week 1 7/25/2012 5Week 2 8/1/2012 5Week 3 8/8/2012 5Week4 8/15/2012 5Week 5 8/22/2012 5Week 6 8/29/2012 54DCTs images of NSCLC patients were imported to RayStation, a treatment planning system. 4DCT DatePlanning week 7/13/2012Week 1 7/25/2012Week 2 8/1/2012Week 3 8/8/2012Week4 8/15/2012Week 5 8/22/2012Week 6 8/29/2012Table 1. Patient total 4DCTs with corresponding dates. Fig 1. Fractionation assigning.  Table 2. Completed fractionation scheme. MOSAIQ fraction dates examined and matched with 4DCTs dates.Accessed  MOSAIQ to view the treatment dates.I.    Fractionation scheme determination   II.    Tumor regression identificationObjectiveBackgroundLower than-25%GTV percent change evaluation• For each patient, fourlandmarks were placed atvessel bifurcations around thetumor to classify inelastic orelastic change. Inelastic caseswere defined if the tumorregressed while the surroundingnormal tissue remains intact,and elastic regressions weredefined if the tumor regressedwith the surrounding normaltissue moving concentricallywith the tumor border.• Physician approved grosstumor volume (GTV) contours(purple) in the planning week.• Using deep-learning basedautomatically segmented GTVcontour (green) in the lastweek, the GTV volume changewas quantified.Planning week Last weekResultsRegression, go to step 3.Fig 2. Tumor regression identification in planning week and last week 4DCTs of one NSCLC case.Fig 3. Planning and last week 4DCTs of one NSCLC case with landmarks around the tumor.I.  Fractionation scheme determination   • 65 fractionation schemes defined to date.  II.    Tumor regression identificationGTV PWGTV LWPercent changeType of regression9.63 5.8 -39% inelastic11.09 5.04 -54% inelastic44.22 32.76 -25% inelasticTable 3. Sample summary of tumor regression identification. The rest of the data can be provided to the interested reader.   I. This work will facilitate thedetermination of the accumulateddose at each week where 4DCTswere taken.II. The tumor regression identificationwill reduce the inaccuracy of imageregistrations, improving accuracyof delivered dose estimation.ReferencesStep 1 Step 2Step 3• Evaluation of the GTV percent change.Future directions• Improve the robustness of theidentification of the type of regressionfor difficult cases where tumor havenon-uniform changes.• 16 patients have been evaluated for tumor response to date.§ Fractionation regimens are defined in the planningphase of radiotherapy (RT) to maximize tumordestruction and minimize damage to surroundingtissues. However, the planned dose is not accuratein representing the delivered dose due to inter-fractional anatomical changes that occur duringtreatment, such as tumor regression.§ Dose accumulation can more accurately representthe delivered dose. It consists of doses recomputedon longitudinal images during treatment based onthe delivered fractions.§ These recalculated doses are then mapped to areference image before being summed. The dosemapping process depends on deformable imageregistration (DIR), which establishes a voxel-voxelcorrespondence between two images. However, theprecision of DIR can be affected by tumor response,thus confounding the ability to estimate the totaldose delivered accurately. Tumor response is mainlydivided into inelastic regression: the tissue usuallyremains intact and does not move along with the tumorand elastic regression: the healthy tissue movesconcentrically with the tumor.§ To our knowledge, this will be the first workflowin RT to define tumor regression. This will allowmore accurate delivered dose estimation whichcan be linked to the toxicity information in follow-up images, ultimately improving treatmentoutcomes.Work impact

A step towards true delivered dose with dose accumulation in radiotherapy

https://openworks.mdanderson.org/cgi/viewcontent.cgi?article=1188&context=sumexp21

A step towards true delivered dose with dose accumulation in radiotherapy

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