Evaluating the Quality of Patient-Specific Deformable Image Registration in Adaptive Radiotherapy Using a Digitally Enhanced Head and Neck Phantom

Round 1

Reviewer 1 Report

The authors indicate that this approach is restricted to a normal range of  head neck patients with a standard setup position - please elaborate on what is outside the normal range and set up HD patients (an example(s)).

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

This paper proposes a methodology based on a Deformable Vector Field (DVF) able to evaluate the quality of image registrations from Computed Tomography (CT) and on-board Cone-Beam CT (CBCT).

The abstract is poor, I suggest extending it including more information (about 200 words maximum, see guidelines for authors) on your method in accordance with the background, methods, results, and conclusion, by highlighting also its strength.

Authors report a general overview without exhibiting an exhaustive state-of-the-art, the latter could be extended. I suggest also mentioning the following paper related to the decomposition and features extraction of DICOM images, it includes also information related to CT: https://doi.org/10.1145/3216122.3216127

Section 2 (Materials and Methods) describes the presented solution, properly, reporting also a well-detailed information.

Similarly, “Discussion” reports an exhaustive discussion about the data presented in “Results”, explaining how these ones can be considered valid (statistical information are included) and useful for a reader.

Minors:

-       Spell checking and typos.

-       I suggest extending the Conclusion reporting the most important results useful to corroborate the key-points of your paper. 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

From my view, this paper is well organized and the proposed method is valuable for this research filed. After reviewed this paper, there are some questions and suggestions as follows.

1. Some figures need to be enhanced in terms of quality and resolution.
2. You must review all significant similar works that have been done. Also, review some of the good recent works that have been done in this area and are more similar to your paper. 
3. What are the advantages and disadvantages of this study compared to the existing studies in this area? This needs to be addressed explicitly and in a separate subsection.
4. There are many grammatical mistakes and typo errors.
5. Many paragraphs are short and not considered as a meaningful section.
6. The proposed method should be compared with at least 3 other novel methods.
7. The experimental results indicate that they perform well, but providing a stronger theoretical analysis and justification for the algorithm would be more convincing. To clearly state the objective of the research in terms of problems to address and expected results and show how the proposed technique will advance the state of the art by overcoming the limitations of the existing work. Also, the results obtained must be interpreted.
8. It is necessary to experimentally analyze the proposed algorithm in terms of time consumed and compare with other algorithms.

Some final cosmetic comments:
* The results of your comparative study should be discussed in-depth and with more insightful comments on the behaviour of your algorithm on various case studies. Discussing results should not mean reading out the tables and figures once again.
* Avoid lumping references as in [x, y] and all other. Instead summarize the main contribution of each referenced paper in a separate sentence. For scientific and research papers, it is not necessary to give several references that say exactly the same. Anyway, that would be strange, since then what is innovative scientific contribution of referenced papers? For each thesis state only one reference.
* Avoid using first person.
* Avoid using abbreviations and acronyms in title, abstract, headings and highlights.
* Please avoid having heading after heading with nothing in between, either merge your headings or provide a small paragraph in between.
* The first time you use an acronym in the text, please write the full name and the acronym in parenthesis. Do not use acronyms in the title, abstract, chapter headings and highlights.
* The results should be further elaborated to show how they could be used for the real applications.

* Are all the images used in this work copyrights free? If not, have the authors obtained proper copyrights permission to re-use them? Please kindly clarify, and this is just to ensure all the figures are fine to be published in this work.

* Also, the list of references should be carefully checked to ensure consistency with between all references and their compliances with the journal policy on referencing.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The manuscript has been improved, and the authors responded to all of my comments.

Reviewer 3 Report

Good revisions have been made in the paper and the revised version has the necessary qualities for acceptance compared to the previous version. In my opinion, the article is acceptable in its current form.