scholarly journals Impact of Esophageal Motion on Dosimetry and Toxicity With Thoracic Radiation Therapy

2019 ◽  
Vol 18 ◽  
pp. 153303381984907 ◽  
Author(s):  
Hao Gao ◽  
Chris R. Kelsey ◽  
John Boyle ◽  
Tianyi Xie ◽  
Suzanne Catalano ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Therapy ◽  
Normal Tissue ◽  
Normal Tissue Complication Probability ◽  
Advanced Lung Cancer ◽  
Thoracic Radiation ◽  
The Mean ◽  
Intrafractional Motion ◽  
Esophageal Motion ◽  
The Impact

Purpose: To investigate the impact of intra- and inter-fractional esophageal motion on dosimetry and observed toxicity in a phase I dose escalation study of accelerated radiotherapy with concurrent chemotherapy for locally advanced lung cancer. Methods and Materials: Patients underwent computed tomography imaging for radiotherapy treatment planning (CT1 and 4DCT1) and at 2 weeks (CT2 and 4DCT2) and 5 weeks (CT3 and 4DCT3) after initiating treatment. Each computed tomography scan consisted of 10-phase 4DCTs in addition to a static free-breathing or breath-hold computed tomography. The esophagus was independently contoured on all computed tomographies and 4DCTs. Both CT2 and CT3 were rigidly registered with CT1 and doses were recalculated using the original intensity-modulated radiation therapy plan based on CT1 to assess the impact of interfractional motion on esophageal dosimetry. Similarly, 4DCT1 data sets were rigidly registered with CT1 to assess the impact of intrafractional motion. The motion was characterized based on the statistical analysis of slice-by-slice center shifts (after registration) for the upper, middle, and lower esophageal regions, respectively. For the dosimetric analysis, the following quantities were calculated and assessed for correlation with toxicity grade: the percent volumes of esophagus that received at least 20 Gy (V20) and 60 Gy (V60), maximum esophageal dose, equivalent uniform dose, and normal tissue complication probability. Results: The interfractional center shifts were 4.4 ± 1.7 mm, 5.5 ± 2.0 mm and 4.9 ± 2.1 mm for the upper, middle, and lower esophageal regions, respectively, while the intrafractional center shifts were 0.6 ± 0.4 mm, 0.7 ± 0.7 mm, and 0.9 ± 0.7 mm, respectively. The mean V60 (and corresponding normal tissue complication probability) values estimated from the interfractional motion analysis were 7.8% (10%), 4.6% (7.5%), 7.5% (8.6%), and 31% (26%) for grade 0, grade 1, grade 2, and grade 3 toxicities, respectively. Conclusions: Interfractional esophageal motion is significantly larger than intrafractional motion. The mean values of V60 and corresponding normal tissue complication probability, incorporating interfractional esophageal motion, correlated positively with esophageal toxicity grade.

Normal-tissue toxicities of thoracic radiation therapy: esophagus, lung, and spinal cord as organs at risk

2004 ◽  
Vol 18 (1) ◽  
pp. 131-160 ◽  
Author(s):  
Maria Werner-Wasik ◽  
Xiaoli Yu ◽  
Lawrence B Marks ◽  
Timothy E Schultheiss
Keyword(s):  
Spinal Cord ◽  
At Risk ◽  
Radiation Therapy ◽  
Normal Tissue ◽  
Organs At Risk ◽  
Thoracic Radiation

scholarly journals Patient setup error and day-to-day esophageal motion error analyzed by cone-beam computed tomography in radiation therapy

2010 ◽  
Vol 49 (4) ◽  
pp. 485-490 ◽  
Author(s):  
Hideomi Yamashita ◽  
Akihiro Haga ◽  
Yayoi Hayakawa ◽  
Kae Okuma ◽  
Kiyoshi Yoda ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Therapy ◽  
Cone Beam Computed Tomography ◽  
Cone Beam ◽  
Setup Error ◽  
Motion Error ◽  
Patient Setup ◽  
Esophageal Motion

A treatment planning comparison of proton therapy and intensity-modulated radiotherapy (IMRT) for prostate cancer using the normal tissue complication probability (NTCP).

2016 ◽  
Vol 34 (2_suppl) ◽  
pp. 153-153
Author(s):  
Benjamin Walker Fischer-Valuck ◽  
Lindsey Olsen ◽  
Thomas Mazur ◽  
Michael Altman ◽  
Beth Bottani ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Proton Therapy ◽  
Normal Tissue ◽  
Normal Tissue Complication Probability ◽  
Phase Iii ◽  
High Dose ◽  
Rectal Toxicity ◽  
Rectal Balloon ◽  
Intensity Modulated ◽  
The Mean

153 Background: The volume of rectum receiving high-dose (i.e. > or = 60 Gy) is consistently associated with the risk of Grade > or = 2 rectal toxicity or rectal bleeding based on common terminology criteria for adverse events (CTCAE). Our goal was to compare intensity-modulated photon radiotherapy (IMRT) with proton radiotherapy in regard to the rectal dose using the normal tissue complication probability (NTCP). Methods: Between July 2014 and September 2015 the first 10 consecutive low or intermediate risk prostate cancer patients were treated with proton therapy at our institution. All 10 patients were planned with three-dimensional conformal proton therapy (3D-CPT) using two parallel opposed fields as well as comparison IMRT plans. A rectal balloon filled with water was used in all patients treated. Prescribed dose to the prostate was 79.2 Gy or cobalt Gy equivalent (CBE) for protons. Dose-volume histograms were compared. The Lyman-Kutcher-Burman model (n = 0.09, m = 0.13, and TD50 = 76.9 Gy) was used to generate NTCP estimates for both IMRT and proton plans. Results: At least 95% of the planning target volume received the prescription dose for both proton and IMRT plans. Dose constraints placed on the rectum included volume receiving 65 Gy (V65) less than 17% and V40 less than 35%. The mean dose to the rectum was 24.5 Gy (range, 19.5-30.1 Gy) and 31.7 Gy (range, 23.7-39.4 Gy) for the proton and IMRT plans, respectively. The V65 constraint was unachievable in 3 of the proton plans and 3 of the IMRT plans. The mean V70 and V75 for proton plans was 8.4% and 5.4% compared to 7.5% and 4.8% for the IMRT plans. The mean NTCP for proton treatment plans was 7.72% (range, 2.7-11.7%) and 7.92% (range, 1.7-15.3%) for IMRT (P = 0.45). After median follow-up of 6 months, no grade 2 or higher toxicity has been reported. Conclusions: Utilizing NTCP estimations, proton therapy and IMRT have similar predicted rates of rectal toxicity. Currently, a Phase III randomized clinical trial is underway comparing proton therapy and IMRT with regards to rectal toxicity and quality of life.

Systematic Review Evaluating the Timing of Thoracic Radiation Therapy in Combined Modality Therapy for Limited-Stage Small-Cell Lung Cancer

2004 ◽  
Vol 22 (23) ◽  
pp. 4837-4845 ◽  
Author(s):  
Daniel B. Fried ◽  
David E. Morris ◽  
Charles Poole ◽  
Julian G. Rosenman ◽  
Jan S. Halle ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Radiation Therapy ◽  
Small Cell Lung Cancer ◽  
Cell Lung Cancer ◽  
Small Cell ◽  
Small Cell Lung ◽  
Limited Stage ◽  
Platinum Based Chemotherapy ◽  
Thoracic Radiation ◽  
The Impact

Purpose We employed meta-analytic techniques to evaluate early (E) versus late (L) timing of thoracic radiation therapy (RT) in limited-stage small-cell lung cancer (LS-SCLC). In addition, we assessed the impact of radiation fractionation and chemotherapeutic regimen on timing. Methods Randomized trials published after 1985 addressing timing of RT relative to chemotherapy in LS-SCLC were included. Trials were analyzed by risk ratio (RR), risk difference, and number-needed-to-treat methods. Results Overall survival (OS) RRs for all studies were 1.17 at 2 years (95% CI, 1.02 to 1.35; P = .03) and 1.13 at 3 years (95% CI, 0.92 to 1.39; P = .2), indicating a significantly increased 2-year survival for ERT versus LRT patients and suggestive of a similar trend at 3 years. Subset analysis of studies using hyperfractionated RT revealed OS RR for ERT versus LRT of 1.44 (95% CI, 1.17 to 1.77; P = .001) and 1.39 (95% CI, 1.02 to 1.90; P = .04) at 2 and 3 years, respectively, indicating a survival benefit of ERT versus LRT. Studies using once-daily fractionation showed no difference in 2- and 3-year OS RRs for ERT compared with LRT. Studies using platinum-based chemotherapy had OS RRs of 1.30 (95% CI, 1.10 to 1.53; P = .002) and 1.35 (95% CI, 1.07 to 1.70; P = .01) at 2 and 3 years, respectively, favoring ERT. Studies using nonplatinum-based chemotherapy regimens had nonsignificant differences in OS. Conclusion A small but significant improvement in 2-year OS for ERT versus LRT in LS-SCLC was observed, similar to the benefit of adding RT to chemotherapy or prophylactic cranial irradiation. A greater difference was evident for hyperfractionated RT and platinum-based chemotherapy.

Implications of learning effects for hospital costs of new health technologies: The case of intensity modulated radiation therapy

2007 ◽  
Vol 23 (2) ◽  
pp. 248-254 ◽  
Author(s):  
Julia Bonastre ◽  
Eric Noël ◽  
Julie Chevalier ◽  
Jean Pierre Gerard ◽  
Dimitri Lefkopoulos ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Direct Cost ◽  
Random Effect ◽  
Intensity Modulated Radiation Therapy ◽  
Learning Effects ◽  
Reimbursement Mechanisms ◽  
Health Technologies ◽  
Intensity Modulated ◽  
The Mean ◽  
The Impact

Objectives: The impact of learning effects on the variability of costs of new health technologies in a prospective payment system (PPS) through the case of intensity modulated radiation therapy (IMRT) was studied.Methods: A series of consecutive patients treated in nine medical centers was enrolled in a prospective study. Direct costs were assessed from the perspective of the healthcare providers. We used a two-level model to explain the variability of costs: patients nested within centers. Learning effects at the center level were considered through a fixed effect (the learning curve slope) and a random effect (the initial cost level). Covariates were introduced to explain the patterns of variation in terms of patient characteristics.Results: The mean direct cost of IMRT was €5,962 (range, €2,414–€24,733). Manpower accounted for 53 percent of this cost. Learning effects explained 42 percent of the variance between centers (which was 88 percent of the total variance) and were associated with a substantial decrease in treatment costs. The mean initial treatment direct cost was €6,332 in centers with a previous experience of IMRT, whereas it was €14,192 in centers implementing IMRT for the first time. Including logistics costs and overhead, the full cost of IMRT was €10,916. Average reimbursement was €6,987.Conclusions: Learning effects are a strong confounding factor in the analysis of costs of innovative health technologies involving learning effects. In a PPS, innovative health technology involving learning effects necessitates specific reimbursement mechanisms.

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