Study for reducing lung dose of upper thoracic esophageal cancer radiotherapy by auto-planning: volumetric-modulated arc therapy vs intensity-modulated radiation therapy

Personalized selection of unequal sub-arc collimator angles in VMAT for multiple brain metastases

PURPOSE

Investigating the effects of unequal sub-arc personalized collimator angle selection on the quality of Volumetric Modulated Arc Therapy (VMAT) plans for treating multiple brain metastases.

METHODS

This study included 21 patients, each with 2-4 target volumes of multiple brain metastases. Two stereotactic radiotherapy (SRT) approaches were utilized: sub-arc collimator VMAT (SAC-VMAT) and fixed collimator VMAT (FC-VMAT). In the SAC-VMAT group, multi-leaf collimators (MLC) shaped the target area, dividing the full arc into four unequal sub-arcs under the beam's eye view (BEV). Each sub-arc had an appropriate collimator angle selected to mitigate 'island blocking problems'. Conversely, the FC-VMAT group used a fixed collimator angle of 15° or 345°. A comparative analysis of the dosimetric parameters of the target volumes and normal tissues, along with the monitor units (MU), was conducted between the two groups.

RESULTS

The mean dose and dose-volume to normal brain tissue (2-26 Gy, with a step of 2 Gy) were significantly lower in the SAC-VMAT group (P < 0.01). There was no statistical difference between the two groups in dose to the target volumes, conformity index (CI), homogeneity index (HI), and other normal tissues (P > 0.05). Compared with the FA-VMAT group, the SAC-VMAT group significantly reduced the gradient index (GI) (4.5 ± 0.59 vs 5.2 ± 0.75, P < 0.001) and MU (1774.33 ± 181.77 vs 2001.0 ± 344.86, P < 0.001). Notably, with an increase in the number of PTV, the SAC-VMAT group demonstrated more significant improvements in the dose-volume of normal brain tissue, GI, and MU.

CONCLUSIONS

In this study, personalized selection of the unequal sub-arc collimator angle ensured the prescribed dose to the PTV, CI, and HI, while significantly reducing the GI, MU, and the dose to normal brain tissue in the VMAT plan for multi-target brain metastases in the cohort of cases with 2-4 target volumes. Particularly as the number of targets increase, the advantages of this method become more pronounced.

Optimization of sub-arc collimator angles in volumetric modulated arc therapy: a heatmap-based blocking index approach for multiple brain metastases

To develop and assess an automated Sub-arc Collimator Angle Optimization (SACAO) algorithm and Cumulative Blocking Index Ratio (CBIR) metrics for single-isocenter coplanar volumetric modulated arc therapy (VMAT) to treat multiple brain metastases. This study included 31 patients with multiple brain metastases, each having 2 to 8 targets. Initially, for each control point, the MLC blocking index was calculated at different collimator angles, resulting in a two-dimensional heatmap. Optimal sub-arc segmentation and collimator angle optimization were achieved using an interval dynamic programming algorithm. Subsequently, VMAT plans were designed using two approaches: SACAO and the conventional Full-Arc Fixed Collimator Angle. CBIR was calculated as the ratio of the cumulative blocking index between the two plan approaches. Finally, dosimetric and planning parameters of both plans were compared. Normal brain tissue, brainstem, and eyes received better protection in the SACAO group (P < 0.05).Query Notable reductions in the SACAO group included 11.47% in gradient index (GI), 15.03% in monitor units (MU), 15.73% in mean control point Jaw area (AJaw,mean), and 19.14% in mean control point Jaw-X width (WJaw-X,mean), all statistically significant (P < 0.001). Furthermore, CBIR showed a strong negative correlation with the degree of plan improvement. The SACAO method enhanced protection of normal organs while improving transmission efficiency and optimization performance of VMAT. In particular, the CBIR metrics show promise in quantifying the differences specifically in the 'island blocking problem' between SACAO and conventional VMAT, and in guiding the enhanced application of the SACAO algorithm.

Efficacy of the collapsed cone algorithm calculated radiotherapy plans in intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT): A comparative dosimetric study in tumors of thorax

AIM

In this study, efficacy of collapsed cone algorithm-generated intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) were evaluated for treatment of thoracic esophageal cancer.

MATERIALS AND METHODS

Ten previously treated patients with VMAT were considered for evaluation. The planning parameters were evaluated in terms of max dose, mean dose, Homogeneity Index, Conformity Index for planning target volume, and organ at risk doses. Total monitor unit, treatment time, and gamma passing index were also reported.

RESULTS

The target dose coverage of the VMAT and IMRT plans achieved the clinical dosimetric criteria for all ten patients in the evaluation. Under the condition of equivalent target dose distribution, the VMAT plan's Conformity Index, monitor unit, treatment time, and gamma passing index rate were superior than in the IMRT plan, and the result was statistically significant.

CONCLUSION

Collapsed cone algorithm-based VMAT can have a more effective and better approach for esophageal cancer than IMRT.

Novel in-house knowledge-based automated planning system for lung cancer treated with intensity-modulated radiotherapy

PURPOSE

The goal of this study was to propose a knowledge-based planning system which could automatically design plans for lung cancer patients treated with intensity-modulated radiotherapy (IMRT).

METHODS AND MATERIALS

From May 2018 to June 2020, 612 IMRT treatment plans of lung cancer patients were retrospectively selected to construct a planning database. Knowledge-based planning (KBP) architecture named αDiar was proposed in this study. It consisted of two parts separated by a firewall. One was the in-hospital workstation, and the other was the search engine in the cloud. Based on our previous study, A‑Net in the in-hospital workstation was used to generate predicted virtual dose images. A search engine including a three-dimensional convolutional neural network (3D CNN) was constructed to derive the feature vectors of dose images. By comparing the similarity of the features between virtual dose images and the clinical dose images in the database, the most similar feature was found. The optimization parameters (OPs) of the treatment plan corresponding to the most similar feature were assigned to the new plan, and the design of a new treatment plan was automatically completed. After αDiar was developed, we performed two studies. The first retrospective study was conducted to validate whether this architecture was qualified for clinical practice and involved 96 patients. The second comparative study was performed to investigate whether αDiar could assist dosimetrists in improving the quality of planning for the patients. Two dosimetrists were involved and designed plans for only one trial with and without αDiar; 26 patients were involved in this study.

RESULTS

The first study showed that about 54% (52/96) of the automatically generated plans would achieve the dosimetric constraints of the Radiation Therapy Oncology Group (RTOG) and about 93% (89/96) of the automatically generated plans would achieve the dosimetric constraints of the National Comprehensive Cancer Network (NCCN). The second study showed that the quality of treatment planning designed by junior dosimetrists was improved with the help of αDiar.

CONCLUSIONS

Our results showed that αDiar was an effective tool to improve planning quality. Over half of the patients' plans could be designed automatically. For the remaining patients, although the automatically designed plans did not fully meet the clinical requirements, their quality was also better than that of manual plans.

Reduction of oesophageal toxicity with VMAT dose-sparing radiotherapy in thoracic metastatic spinal cord compression: A feasibility study

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Oesophageal delineation took a mean of 8.6 min.

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Significant dose reduction for oesophageal V7.7 Gy, D2% and Dmean were achieved, without significant change in CTV coverage.

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Reduction of oesophageal dose may lead to reduced acute toxicity in this patient group where quality of life is a key concern.

Background

Palliative radiotherapy for metastatic spinal cord compression (MSCC) is given to halt disease progression and sustain quality of life for patients with advanced cancer. Radiotherapy can however induce toxicity, contradicting treatment intention. Advanced radiotherapy offers possibility of sparing organs at risk (OARs). The purpose of this dosimetric study is to establish the feasibility and potential benefits of dose sparing of the oesophagus.

Materials and methods

30 patients receiving radiotherapy of 30 Gy/10# for MSCC were retrospectively included and the oesophagus delineated. Two new dose plans were created for each patient (eso-crop and PTV-crop) with the intention of optimising the oesophageal dose. In the eso-crop plan maintaining full target volume coverage was prioritised, for the PTV-crop plan oesophageal dose was further reduced through cropping the planning target volume (PTV) overlapping oesophageal/PTV-area. Time added for delineation was measured. Plans were compared using Wilcoxon signed rank test with p < 0.05 considered statistically significant. Bivariate associations between dose metrics and patient characteristics were quantified using linear regression models.

Results

Oesophageal delineation took a mean of 8.6 min. There was significant dose reduction for both V7.7 Gy, D2% and mean oesophageal dose, without significant change in CTV coverage. The mean achievable oesophageal dose reduction was 29.1% and 50.4% for the eso-crop and PTV crop plans, respectively. Minor changes in dose distribution to the lungs was observed, with increased mean and V20Gy for the eso-crop plan and decreased V5Gy to the PTV-crop plan.

Conclusion

This study demonstrated the possibility of significant dose sparing of the oesophageal dose using single arc VMAT without impacting on CTV coverage.

Planning evaluation of a novel volume-based algorithm for personalized optimization of lung dose in VMAT for esophageal cancer

Radiotherapy treatment planning (RTP) is time-consuming and labor-intensive since medical physicists must devise treatment plans carefully to reduce damage to tissues and organs for patients. Previously, we proposed the volume-based algorithm (VBA) method, providing optimal partial arcs (OPA) angle to achieve the low-dose volume of lungs in dynamic arc radiotherapy. This study aimed to implement the VBA for esophageal cancer (EC) patients and compare the lung dose and delivery time between full arcs (FA) without using VBA and OPA angle using VBA in volumetric modulated arc therapy (VMAT) plans. We retrospectively included 30 patients diagnosed with EC. RTP of each patient was replanned to 4 VMAT plans, including FA plans without (FA-C) and with (FA + C) dose constraints of OARs and OPA plans without (OPA-C) and with (OPA + C) dose constraints of OARs. The prescribed dose was 45 Gy. The OARs included the lungs, heart, and spinal cord. The dose distribution, dose-volume histogram, monitor units (MUs), delivery time, and gamma passing rates were analyzed. The results showed that the lung V₅ and V₁₀ in OPA + C plans were significantly lower than in FA + C plans (p < 0.05). No significant differences were noted in planning target volume (PTV) coverage, lung V₁₅, lung V₂₀, mean lung dose, heart V₃₀, heart V₄₀, mean heart dose, and maximal spinal cord dose between FA + C and OPA + C plans. The delivery time was significantly longer in FA + C plans than in OPA + C plans (237 vs. 192 s, p < 0.05). There were no significant differences between FA + C and OPA + C plans in gamma passing rates. We successfully applied the OPA angle based on the VBA to clinical EC patients and simplified the arc angle selection in RTP. The VBA could provide a personalized OPA angle for each patient and effectively reduce lung V₅, V_10, and delivery time in VMAT.

Investigation of Predictors to Achieve Acceptable Lung Dose in T-Shaped Upper and Middle Esophageal Cancer With IMRT and VMAT

Purpose

The purpose of this study is to investigate whether there are predictors and cutoff points that can predict the acceptable lung dose using intensity-modulated radiation therapy (IMRT) and volume-modulated arc therapy (VMAT) in radiotherapy for upper ang middle esophageal cancer.

Material and Methods

Eighty-two patients with T-shaped upper-middle esophageal cancer (UMEC) were enrolled in this retrospective study. Jaw-tracking IMRT plan (JT-IMRT), full-arc VMAT plan (F-VMAT), and pactial-arc VMAT plan (P-VMAT) were generated for each patient. Dosimetric parameters such as MLD and V20 of total lung were compared among the three plannings. Ten factors such as PCTV_inferior length and PCTV_inferior length/total lung length were calculated to find the predictors and cutoff points of the predictors. All patients were divided into two groups according to the cutoff points, and the dosimetric differences between the two groups of the three plans were compared. ANOVA, receiver operating characteristic (ROC) analysis, and Mann–Whitney U-test were performed for comparisons between datasets. A p <0.05 was considered statistically significant.

Result

The quality of the targets of the three plannings was comparable. The total lung dose in P-VMAT was significantly lower than that in JT IMRT and F-VMAT. Monitor unit (MU) of F-VMAT and P-VMAT was significantly lower than that of JT IMRT. ROC analysis showed that among JT IMRT, F-VMAT, and P-VMAT, PCTV_i-L, and PCTV_i-L/TL_L had diagnostic power to predict the suitability of RT plans according to lung dose constraints of our department. For JT IMRT, the cutoff points of PCTV_i-L and PCTV_i-L/TL_L were 16.6 and 0.59. For F-VMAT, the cutoff points of PCTV_i-L and PCTV_i-L/TL_L were 16.75 and 0.62. For P-VMAT, the cutoff points of PCTV_i-L and PCTV_i-L/TL_L were 15.15 and 0.59. After Mann–Whitney U-test analysis, it was found that among the three plannings, the group with lower PCTV_i-L and PCTV_i-L/TL_L could significantly reduce the dose of total lung and heart (p <0.05).

Conclusion

PCTV_{i-L <}16.6 and PCTV_i-L/TL_L <0.59 for JT IMRT, PCTV_{i-L <}16.75 and PCTV_i-L/TL_L <0.62 for F-VMAT and PCTV_{i-L <}15.15, and PCTV_i-L/TL_L <0.59 for P-VMAT can predict whether patients with T-shaped UMEC can meet the lung dose limits of our department.

A novel CRT-IMRT-combined (Co-CRIM) planning technique for peripheral lung stereotactic body radiotherapy in pinnacle treatment planning system

Objectives

This study attempts to explore a novel peripheral lung stereotactic body radiotherapy (SBRT) planning technique that can balance the pros and cons of three‐dimensional conformal radiotherapy (CRT) and intensity‐modulated radiation therapy (IMRT) / volumetric modulated arc therapy (VMAT).

Methods

Treatment plans were retrospectively designed based on CRT, IMRT, VMAT, and the proposed CRT‐IMRT‐combined (Co‐CRIM) techniques using Pinnacle treatment planning system (TPS) for 20 peripheral lung cancer patients. Co‐CRIM used an inverse optimization algorithm available in Pinnacle TPS. To develop a Co‐CRIM plan, the number of segments in each field was limited to one, the minimum segment area was set to the internal target volume (ITV), and the minimum monitor units (MU) of the segment was the quotient of fractional dose divided by twice the number of total fields. The performance of Co‐CRIM was then compared with other techniques.

Results

For conformity index (CI), Co‐CRIM performed comparably to IMRT/VMAT but better than CRT. For gradient index (GI), Co‐CRIM was similar to IMRT/VMAT or CRT. For heterogeneity index (HI), Co‐CRIM was comparable to IMRT/VMAT, higher than CRT. The dosimetric results of spinal cord and lung with Co‐CRIM were better than CRT, comparable to IMRT, but inferior to VMAT. The MU resulted from Co‐CRIM was lower than IMRT/VMAT but higher than CRT. For plan verification γ passing rate, Co‐CRIM was higher than IMRT/VMAT, comparable to CRT. For planning time, Co‐CRIM was shorter than CRT or VMAT but similar to IMRT.

Conclusions

The proposed Co‐CRIM technique on Pinnacle TPS is an effective planning technique for peripheral lung SBRT.

Dosimetric Comparison, Treatment Efficiency Estimation, and Biological Evaluation of Popular Stereotactic Radiosurgery Options in Treating Single Small Brain Metastasis

Objectives

This study aimed to show the advantages of each stereotactic radiosurgery (SRS) treatment option for single small brain metastasis among Gamma Knife (GK), Cone-based VMAT (Cone-VMAT), and MLC-based CRT (MLC-CRT) plans.

Materials and Methods

GK, Cone-VMAT, and MLC-CRT SRS plans were retrospectively generated for 11 patients with single small brain metastasis whose volume of gross tumor volume (GTV) ranged from 0.18 to 0.76 cc (median volume 0.60 cc). Dosimetric parameters, treatment efficiency, and biological parameters of the three techniques were compared and evaluated. The metric variation with the planning target volume (PTV) was also studied.

Results

The conformity index (CI) was similar in GK and MLC-CRT plans, higher than Cone-VMAT. Cone-VMAT achieved comparable volume covered by 12 Gy (V12) and gradient index (GI) as GK, lower than MLC-CRT. The heterogeneity index (HI) of GK, Cone-VMAT, and MLC-CRT decreased sequentially. GK gave the lowest volume covered by 3 Gy (V3) and 6 Gy (V6), while MLC-CRT got the highest. The beam-on time and treatment time of GK, Cone-VMAT, and MLC-CRT decreased in turn. Tumor control probability (TCP) of all three SRS plans was greater than 98%, and normal tissue complication probability (NTCP) of all organs at risk (OARs) was below 0.01%. GK and Cone-VMAT resulted in superior TCP and NTCP of the normal brain tissue than MLC-CRT. The relative value of Cone-VMAT and GK for all metrics hardly changed with the target volume. Except for the unchanged HI and TCP, the other results of MLC-CRT with respect to GK improved as the target volume increased. MLC-CRT could produce higher CI than GK and Cone-VMAT when the target volume increased above 2 and 1.44 cc, respectively.

Conclusion

For single small brain metastases, Cone-VMAT may be used as an alternative to GK-free centers. In addition to the advantage of short treatment time, MLC-CRT showed superiority in CI as the target volume increased. Treatment centers can choose appropriate SRS technique on a case-by-case basis according to institutional conditions and patients’ individual needs.

Dosimetric comparison and biological evaluation of fixed-jaw intensity-modulated radiation therapy for T-shaped esophageal cancer

Background

To evaluate the dosimetric and biological benefits of the fixed-jaw (FJ) intensity-modulated radiation therapy (IMRT) technique for patients with T-shaped esophageal cancer.

Methods

FJ IMRT plans were generated for thirty-five patients and compared with jaw tracking (JT) IMRT, static jaw (SJ) IMRT and JT volumetric modulated arc therapy (VMAT). Dosimetric parameters, tumor control probability (TCP) and normal tissue complication probability (NTCP), monitor units (MUs), delivery time and gamma passing rate, as a measure of dosimetric verification, were compared. The correlation between the length of PTV-C below the upper boundary of lung tissue (PTV-C_inferior) and dosimetric parameters and NTCP of the lung tissue were analyzed.

Results

The homogeneity and conformity of the target in the four plans were basically equivalent. When compared to the JT IMRT and SJ IMRT plans, FJ IMRT plan led to a statistically significant improvement in the NTCP and low-middle dosimetric parameters of the lung, and the improvement had a moderately positive correlation with the length of PTV-C_inferior, with a correlation coefficient ranging from 0.523 to 0.797; the FJ IMRT plan exhibited better lung sparing in low-dose volumes than the JT VMAT plan. The FJ IMRT plan had similar MUs (888 ± 99) and delivery times (516.1 ± 54.7 s) as the JT IMRT plan (937 ± 194, 522 ± 5.6 s) but higher than SJ IMRT (713 ± 137, 488.8 ± 45.2 s) and JT VMAT plan (517 ± 59, 263.7 ± 43.3 s).

Conclusions

The FJ IMRT technique is superior in reducing the low-dose volumes of lung tissues for patients with T-shaped esophageal cancer.

Can the Student Outperform the Master? A Plan Comparison Between Pinnacle Auto-Planning and Eclipse knowledge-Based RapidPlan Following a Prostate-Bed Plan Competition

Purpose:

Pinnacle Auto-Planning and Eclipse RapidPlan are 2 major commercial automated planning engines that are fundamentally different: Auto-Planning mimics real planners in the iterative optimization, while RapidPlan generates static dose objectives from estimations predicted based on a prior knowledge base. This study objectively compared their performances on intensity-modulated radiotherapy planning for prostate fossa and lymphatics adopting the plan quality metric used in the 2011 American Association of Medical Dosimetrists Plan Challenge.

Methods:

All plans used an identical intensity-modulated radiotherapy beam setup and a simultaneous integrated boost prescription (68 Gy/56 Gy to prostate fossa/lymphatics). Auto-Planning was used to retrospectively plan on 20 patients, which were subsequently employed as the library to build an RapidPlan model. To compare the 2 engines’ performances, a test set including 10 patients and the Plan Challenge patient was planned by both Auto-Planning (master) and RapidPlan (student) without manual intervention except for a common dose normalization and evaluated using the plan quality metric that included 14 quantitative submetrics ranging over target coverage, spillage, and organ at risk doses. Plan quality metric scores were compared between the Auto-Planning and RapidPlan plans using the Mann-Whitney U test.

Results:

There was no significant difference between the overall performance of the 2 engines on the 11 test cases (P = .509). Among the 14 submetrics, Auto-Planning and RapidPlan showed no significant difference on most submetrics except for 2. On the Plan Challenge case, Auto-Planning scored 129.9 and RapidPlan scored 130.3 out of 150, as compared with the average score of 116.9 ± 16.4 (range: 58.2-142.5) among the 125 Plan Challenge participants.

Conclusion:

Using an innovative study design, an objective comparison has been conducted between 2 major commercial automated inverse planning engines. The 2 engines performed comparably with each other and both yielded plans at par with average human planners. Using a constant-performing planner (Auto-Planning) to train and to compare, RapidPlan was found to yield plans no better than but as good as its library plans.

A hybrid automated treatment planning solution for esophageal cancer

OBJECTIVE

This study aims to investigate a hybrid automated treatment planning (HAP) solution that combines knowledge-based planning (KBP) and script-based planning for esophageal cancer.

METHODS

In order to fully investigate the advantages of HAP, three planning strategies were implemented in the present study: HAP, KBP, and full manual planning. Each method was applied to 20 patients. For HAP and KBP, the objective functions for plan optimization were generated from a dose-volume histogram (DVH) estimation model, which was based on 70 esophageal patients. Script-based automated planning was used for HAP, while the regular IMRT inverse planning method was used for KBP. For full manual planning, clinical standards were applied to create the plans. Paired t-tests were performed to compare the differences in dose-volume indices among the three planning methods.

RESULTS

Among the three planning strategies, HAP exhibited the best performance in all dose-volume indices, except for PTV dose homogeneity and lung V5. PTV conformity and spinal cord sparing were significantly improved in HAP (P < 0.001). Compared to KBP, HAP improved all indices, except for lung V5. Furthermore, the OAR sparing and target coverage between HAP and full manual planning were similar. Moreover, HAP had the shortest average planning time (57 min), when compared to KBP (63 min) and full manual planning (118 min).

CONCLUSION

HAP is an effective planning strategy for obtaining a high quality treatment plan for esophageal cancer.

Dosimetric evaluation of automatic and manual plans for early nasopharyngeal carcinoma to radiotherapy

To investigate dosimetric differences and plan qualities between manual plans and automatic plans for nasopharyngeal carcinoma (NPC) in early stage, and provide better options to maximize the benefits. Sixteen cases diagnosed with early NPC were retrospectively investigated. Conventional step and shoot IMRT with 7-fields and full arc volumetric-modulated arc therapy (VMAT) with double arcs were manually generated by experienced planners and automatically generated by Auto-Planning module in Pinnacle³ respectively, such as IMRT manual-planning (mIMRT), IMRT auto-planning (aIMRT), VMAT manual-planning (mVMAT), and VMAT auto-planning (aVMAT) for each patient. Target coverage, organs at risk sparing, monitor units, and planning times were compared and evaluated. All parameters of plans are able to fulfill International Commission on Radiation Units and Measurements repor (ICRU) 83 recommendations. Automatic plans are comparable or superior to manual plans without time-consuming planning process. The CI and HI for PTVs are better in aVMAT when compared with aIMRT and mVMAT, but those are similar between aIMRT and mVMAT. Automatic plans not only have superior dose homogeneity and conformity in PTVs, but also have better sparing for spinal cord or slightly reduce the doses received by other OARs, while the VMAT plans have better sparing for brain stem, especially the aVMAT plans. However, Dmax, V30, and V40 of brain stem are similar between aIMRT and mVMAT without significant difference. The monitor units and planning time for treatment plans have been significantly decreased through automatic planning technique. The automatic VMAT plan has greater clinical advantages and should be recommended to a better option for treating NPC in early stage, while automatic IMRT would be preferentially considered instead of manual VMAT.

Comparison of treatment plan quality of VMAT for esophageal carcinoma with: flattening filter beam versus flattening filter free beam

Purpose: To investigate the difference in treatment plan quality of volumetric modulated arc treatment (VMAT) for esophageal carcinoma with flattening filter beam (FF) and flattening filter free beam (FFF). Material and methods: A total of fifty-six treatment plans were generated for twenty eight esophageal carcinoma patients with flattening filter beam and flattening filter free beam, using same optimal parameters. The homogeneity index (HI) and conformal index (CI) of targets, and some special points on Dose-Volume Histogram (DVH) curves were used to compare the plan quality. The coverage volumes of 45 Gy, 30 Gy and 20 Gy outside targets (V45Gy, V30Gy and V20Gy ) were used to compare the targets peripheral dose. The MU numbers, measured delivery time and averaged dose rates were used to evaluate the delivery efficiency of treatment plans. Results: A significant decreasing in peripheral dose around targets was found using FFF beams while the dose distributions in targets were equivalent to the plans with FF beams. V45Gy, V30Gy and V20Gy were decreased by 6.46%, 88.18% and 4.40%, respectively. A significant increase in MUs and decrease in treatment time were also found in delivery test. The average MUs was increased by 21.83% and the average treatment time was reduced by down to 11.9%. Conclusions: For esophageal carcinoma, the research showed that the treatment plans with FFF beams could get comparable dose distribution in targets and could significantly reduce the peripheral dose around targets compared to the plans with FF beams.