Comparing Radiation Dose of Cerebral Angiography Using Conventional and High kV Techniques: A Retrospective Study on Intracranial Aneurysm Patients and a Phantom Study

Round 1

Reviewer 1 Report

Notes:

1. Lines 35, 39, 45, 254, 267, 284, 303 are missing spaces before the expanding square bracket “[”.

2. Line 48, should be "p-value".

3. When writing the dimension “Dose area product (DAP)”, it is logical to use the multiplication symbols “×” or “´”, that is, μGy×cm² or μGy´cm² (line 108, 184, 187, table 4).

4. In table 3, the asterisk “*” is marked in red font, and in the explanation to the table - in black, preferably in the explanation “*”.

5. It is preferable to write negative numbers with the symbol “−”, (Table 4)

6. Traditionally write "X-ray" with a capital letter.

I recommend accepting your paper for publication with minimal technical correction.

Note not for corrections. One of the most common methods for estimating the radiation dose is the Monte Carlo method; it can be easily adapted to any research object, to any control geometry, to any X-ray source and to an arbitrary recorder. In tasks for comparing dose characteristics, it is quite appropriate to use it.

Author Response

Your comments are highlighted in grey in the revised manuscript. 

Author Response File: Author Response.docx

Reviewer 2 Report

This paper investigates the radiation dose of cerebral angiography with two different protocols, with both a phantom experimental demonstration and a retrospective series review. In general, the study is well designed and the presented results are reliable and relevant.

As a general comment, the two compared protocols are named conventional and “optimization technique”. However, as authors only evaluate two protocols (low-KV versus high-kV), I would not say that the high-kV protocol is optimized. In order to optimize a technique, several (more than two) options should be tested. For this reason, I would suggest the authors to modify the names of the two explored protocols to, for example, conventional and low-dose or high-kV.

I have some minor comments:

·       -   General language editing is necessary to improve the grammar of the work.

·       -   Table 1: As far as I understand Table 1 present common parameters of both protocols. In this case, I miss kV and mAs of 3DRA

·        -  Why 3DRA and fluoroscopic techniques were kept constant? For the scope of optimization, these parameters could have been modified too. Please, justify this decision.

·         - Table 2: Please, review that the number of decimal positions matches with the order of magnitude of the standard deviation.

·       -   Table 2: I would appreciate if these data were presented graphically. To this aim, data should be grouped in kV, mAs and filtering, to use common axes.

·       -    Table 3: translation of these data to a graph is easy and might help the reader to understand and localize main differences. It might be useful also to present the statistical significance in a head graph, in the same manner as Figure 4.

Author Response

All changes following your comments and suggestion are highlighted in blue. Thank you very much.

Author Response File: Author Response.docx

Reviewer 3 Report

Lines 40-41 Since “high dose” is not defined, more appropriate would be to say that high radiation doses “may cause deterministic skin injury…” (rather than that it causes).

Lines 45-47 Sentence “As the consequence of the difference in DSA properties from each vendor, the work process and factors affect the radiation dose, the proper optimization technique should be concerned.” is unclear, rewording is suggested; there are no vendors of DSA, only of X-ray units used for performing DSA.

Lines 49-50 Local diagnostic reference levels are defined as “DRL for an x-ray procedure set in healthcare facilities within part of a country for a defined clinical imaging task, based on the 75th percentile value of the distribution of the appropriate DRL quantity in a reasonable number (e.g. 10–20) of x-ray rooms.” (ICRP 135) – Authors probably meant that “typical values” were higher than in other institutes (instead of ”local diagnostic reference levels”)?

Line 72 Abbreviation for „subarachnoid haemorrhage” was previously given (SAH), it should be used.

Line 79 No need for the name of the physician.

Line 82-83 If someone wants to calculate typical value, data for at least 20 standard patients should be used or if DMS (or any register) is available, data for > 100 patients (regardless of body mass) (ICRP 135). In case of this study, 61 patients were selected for each protocol (conventional and optimised, line76-77). Suggestion is to elaborate in more detail why in the case of this study patients were selected without considering their body mass.

Line 90 Suggestion: Check whether “DSA” is really part of the X-ray unit model name. Would be strange if it is, as well as if the unit is intended to be used just for the DSA. In addition, it would be useful to add information whether used X-ray unit allows operator to set the kV manually since majority of nowadays interventional X-ray units operates only in the AEC mode.

Lines 92-95 Although article refers to the reference [11], suggestion is to elaborate in more detail why is fluoroscopy given separately from 2DA and 3DRA protocols (since in both cases fluoroscopy may be used as part of DSA procedure) and/or which operation mode(s) are included in 2DA and 3DRA procedure (and which are not included).

Line 98 No need for the name of the physician.

Lines 99-100 Seems like X-ray unit operates under AEC (although previously it was written that kV was set at 70 for conventional and at 90 for optimised protocol, lines 95-96); see also comment on Line 90

Line 102 Part “Collection of cerebral angiographic technique” of the subtitle 2.4. requires rewording – it is not possible to collect the technique

Line 108 Suggestion is to use abbreviation RAK instead of Rak (applies to the rest of the text also)

Line 121 It is not clear what was the intention of placing dosimeters on LE and RE positions - to estimate organ dose of which organs - lens of the eye or the eyes? Lens of the eye (eye lens) were mentioned at the very end of the manuscript (line 301).

Line 129 (Table 1) In the description above Table 1 part explaining that this is for phantom study is missing; why is “Fluoroscopy” bold?

Lines 138-139 First part of the sentence is repetition of the information already given in the last sentence in paragraph 2.5

Lines 151-153 Not sure whether “comparison of patient radiation dose from 2DA technique and total procedure” was performed and results presented later in the text. In addition, it is not clear what is meant by “patient radiation dose from 2DA technique” nor by “total procedure”.

Lines 156-158 Suggestion is to elaborate in more detail why is mean value (mean+-SD) used in case of analysis of patient dose (in addition to median); approach of presenting typical value with mean value has been abandoned long time ago.

Line 172 (Table 2) Why is “2DA PA kV” bold?

Line 172 (Table 2) It is not clear for which mode/protocol “Total number of images” is given.

Line 172 (Table 2) It is not clear for which mode/protocol “Fluoroscopic time (min)” is given.

Line 178-179 It is written that “3DRA and fluoroscopic technique were not modified in this study” which is kind of confusing. Until now, reader of the manuscript might understand that all protocols have been optimised. It should be mentioned earlier (in 2.3. preferably). In addition, previously, in Table 2 (line 172) data was given for “optimised” 3DRA protocol too.

Line 179 and 182 What is meant by “DAP parameters”?

Line 237 (Table 4) Is RAK really measured by DAP-meter? Description of the table should be corrected.

Line 237 (Table 4)  It is not clear for which mode/protocol “Total DAP” and “Total RAK” are given.

Line 274 It is not clear what exactly “parameters” include.

Line 274 It is not clear what is meant by “patient radiation dose”.

Lines 285-287 Suddenly advice is given to ensure follow-up of patients who underwent procedure which is not subject of this manuscript (coiling embolization). Suggestion is to delete this sentence.

Lines 296-303 The same comment as for Line 121.

General comments/suggestions:

1. The term “optimization technique” is used throughout the text, starting with the title. Wouldn’t “optimized technique” do better?

2. Suggestion: To cite the following paper: “W Kirisattayakul, P Pattum, W Munkong, C Khottapat, T Chomkhunthod, P Punikhom, R Karawek, T Prabsattroo, V Pungkun. Cerebral angiographic procedure using high kV technique reduces patient radiation dose during intracranial aneurysmal diagnosis, a retrospective and phantom study, Journal of Medical Imaging and Radiation Sciences, Volume 53, Issue 4, Supplement 1, 2022, Page S2, ISSN 1939-8654, https://doi.org/10.1016/j.jmir.2022.10.007"

3. Suggestion:  To discuss differences between this study and aforementioned study (under 2) in the Discussion part of the paper.

4. Drawbacks of using skin dose measurement for assessment of eye lens doses should be mentioned in the Discussion part.

5. Extensive editing of English language and style required.

Author Response

Thank you so much for you comments and suggestion. All changes following you comments are highlighted in green. The English editing has been performed. Please also see the track changes. 

Author Response File: Author Response.docx