Thematic: Pass node values ​​to the quick mail module to create a custom email template

I am currently working on trying to create an email html template using swift mailer. My problem right now is how can I customize the template to get the values ​​of the nodes and display them in the email template.

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Swift Mailer has a default way of generating the values ​​of all fields using {{body}}

Is there any way to access the values ​​of the fields and display them in the template? Something like the following code that works in the node template

{{content.field_title.value}} or {{node.field_title.value}}

Swift Mailer has a way of generating values ​​through preprocessing, but I can not seem to make it work. Below is the code that is a work in progress.

swiftmailer_preprocess_swiftmailer (& $ variables) {function
$ variables['node_title'] = $ node-> getTitle ();