October 2024 Town Hall
Mentimeter Survey Results

Figure 1 – The current and future picture of vEM techniques

Introduction
The volume EM October 2024 Town Hall was a part of the vEM Technology Forum. The Town Hall was a hybrid event that included the 130 Technology Forum participants as well as approximately 40 participants attending online. As in the previous year, we had an interactive session at the end of the Town Hall that was focused on gathering feedback from our audience of community members. Ninety-six people logged in to Mentimeter to provide responses to questions during this session.

Some of the questions were meant to capture an overview of the field and an indication of where it is going. Many of these questions are the same as those that were asked during the 2023 Town Hall survey. Other questions were posed by individual working groups or industry partners and focused on specific use of vEM community resources and tools or on the desires or direction of the vEM field.

We will continue to collect feedback during interactive sessions at future vEM community events to capture longitudinal trends and best represent the vEM community within the activities of the vEM Working Groups.
 
State of the vEM Field
To understand what vEM techniques the field is moving towards and away from, we asked what vEM techniques are currently being used (Figure 1A) and which you want to use in the future (Figure 1B). Comparing these two outputs (Figure 1C) indicates a desire to shift away from room temperature TEM, cryogenic imaging and serial block face SEM (SBF-SEM), and a desire to shift towards correlative vEM, multi-beam array tomography and synchrotron X-ray imaging. This partially complements the trends seen during last year’s survey  which indicated a desire to shift away from room temperature vEM, SBF-SEM and correlative vEM, and a desire to shift towards multi beam array tomography, cryogenic imaging and X-ray imaging (on- or off-synchrotron).

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​​We next see that vEM techniques have not been taken up consistently across the scientific fields represented by the audience (Figure 2A). Of interest, this measure has decreased compared to last year’s survey results, likely due to a shift in the composition of the audience. Looking at barriers to data processing (Figure 2B), funding (Figure 2C) and access (Figure 2D) within the vEM field, the largest barriers are related to training, user friendliness, choice paralysis and time for data processing, insufficiently large grants for technology acquisition or for sustaining a facility for funding, and time for access to vEM techniques. These responses show some similarities to last year, especially around identification of time and lack of funding for sustaining facilities as barriers; there have also been some shifts to new primary barriers around training, software choice and user friendliness. ​

Figure 2 – Data, funding and access barriers in the vEM field

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​Subject Area Feedback
To understand the needs and preferences of the vEM community, questions on specific topics were put forward by the various vEM Community Working Groups and sponsors of the vEM Technology Forum. These responses will inform and guide those involved in the vEM community over the coming months. 

The community weighed in on ideas related to spreading awareness of the vEM Community (Figure 3A, B) and a few questions related to high pressure freezing samples (Figure 3C, D). Specific research areas which were thought to benefit from vEM, but aren’t yet aware of the technique include pathology, soft materials, archaeology, polymers, etc. And most respondents agreed that the Outreach WG should attempt to make the term volume EM into a defined term similar to how cryoEM is used. 

On the high pressure freezing side, the majority of those present have access to a high pressure freezer (68%) with another 17% indicating that they sometimes have access. In contrast to this, most of the samples prepared for respondents did not require high pressure freezing with 14% of respondents indicating that none of their samples required it and only 7% indicating that all of their samples required it.

Figure 3 – Spreading awareness of vEM and use of high pressure freezing

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​Next, there were a few questions around the most important features of grids (Figure 4A) and TEM support films (Figure 4B) with features such as being tough during handling and having larger open viewing areas scoring higher than being resistant to a wide range of conditions (temp, chemicals, etc). When given a blank slate and asked which features the community would like that aren’t currently available, the most requested feature was that the support films be unbreakable and cheaper. Additional requests were for unique IDs, cell culture specific films, charge stability, large holes in gold foils, gold and carbon half/half, and chloroform free.

Figure 4 – Grid feature preferences

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​Questions related to the characteristics of a typical experiment were next (Figure 5). Respondents indicated that typically, the volume being imaged is between 10 um3 and 100 um3 (35%), with a substantial cohort working in the smaller sample size ranges (1 um3 – 10 um3 and <1 um3) and some working in the larger sizes (Figure 5A). Most respondents were imaging exclusively at either room temperature or cryogenic. The necessary resolution for their projects was typically better than 10 nm with a second contingent in the between 10 – 50 nm group. The average dataset size acquired was between 100 GB and 1 TB with only approximately 15% of respondents working with larger dataset sizes than 1 TB. 

Almost half of all respondents are not currently submitting their data to online repositories (“No – never” and “No – not often”) and only 18% were always submitting their data. Many reasons were given for not depositing data, but the most common were that the data is not their own (i.e., facility staff do not feel able to submit the data) or that it was complicated to do so, the work was unpublished or industry-related. 

Figure 5 – The typical vEM experiment

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Next, two questions were asked focused on how researchers describe their samples (Figure 5A) and the features within the datasets they are most interested in (Figure 5B). These word clouds demonstrate both the necessary metadata needed to appropriately capture the details of vEM experiments and the breadth of the features of interest across the community.

Figure 6 – Sample and feature descriptions

​​vEM is a complementary technique with many others creating the possibility to correlate data across modalities. The word cloud in Figure 8A shows what the community is correlating vEM with, spanning X-ray and many different forms of light microscopy. The Training WG wanted to know what the barriers keeping community members from making a training video were so that they could alleviate them – the biggest response was around not knowing what topic to contribute, with time to record being a close second (Figure 8B). And finally, the community was asked what additional resources beyond the existing WGs, focused interest groups (FIGs) and online resources were needed (Figure 8C). The largest response was a request for topic specific guides/step-by-step instructions, FAQs and meet-ups.

Figure 7 – Correlation of vEM and understanding the needs of the community

​Finally, there were a large number of facility managers and staff in attendance at the Town Hall and due to the technical expertise needed many researchers engage with facilities in order to do research using vEM techniques. For these reasons it is helpful for the community to understand the perspective of the vEM Facility with regards to recovery of costs (Figure 9A) capacity (Figure 9B) and limiting factors related to capacity (Figure 9C). Approximately one third of vEM facilities responding here did not recover costs; and of those that did the costs were either between £0-£50/hr and £50-£100/hr. Thirty-eight percent of facilities were oversubscribed with another 32% at capacity with the limiting factors for these facilities focused around mainly staff resource or a mixture of both staff and microscopy recourse limitations.

Figure 8 – A snapshot of vEM facilities

​The Town Hall at the vEM Technology Forum represented a milestone of 5 years of the vEM Community Initiative existing and working towards the goals of growth and awareness. We took this moment to hear from the community to both brainstorm and then vote on what the Initiative should focus on in the coming years (Figure 7A). Options spanned across all aspects of the vEM techniques and community goals though a clear preference was indicated with Training, Standardisation and Best Practice taking the top three spots. When asked further about what vEM technique or aspect of a technique should be focused on for providing training (Figure 7B) the clear focus was on data processing with the top five answers, representing over 50% of the vote, being Data Analysis, Segmentation Software, AI, Sample Prep and AI Segmentation.

Figure 9 – Direction of travel for the vEM community