I agree that the regulations in the current 12VAC5-481 would benefit from significant revision or replacement. The existing regulations have areas which suffer from ambiguities regarding which regulations apply to different areas of clinical/research practice.

Some representative examples:

1. The current regulations appear to apply specific radioactive material definitions to therapeutic x-ray machine uses. (For example, the definitions of "Written Directive", "Medical Event", "Authorized User"). This tends to be a source of confusion for licensees and users of both radioactive material-based and x-ray based equipment.
2. Certain definitions addressing the same concept are inconsistent (for instance, "Medical Event", "Misadministration", and "Reportable Event").
3. The definition of "Radiation Machine" is confusing as it currently excludes devices whose only source of radiation is radioactive material.
4. Proposed revisions/replacement regulations should more clearly state which regulations apply to different categories of devices (radioactive material-based, x-ray based, charged particle based) to resolve current ambiguities.

The current 12VAC5-481 regulations have also fallen behind developments in both clinical radiation oncology practice and preclinical radiation research. In particular:

1. Many clinical treatment devices now include integrated x-ray-based "on-board" imaging systems that are used to verify patient position on the device (i.e. they are non-diagnostic and non-therapeutic). Current regulations are ambiguous in how these non-diagnostic, non-therapeutic x-ray systems should be regulated.  Any revision/replacement of 12VAC5-481 should address these devices and should recognize that as they are an integrated part of a therapeutic treatment system, the positioning/verification x-ray systems should not require qualifications for operation beyond which is required to use the primary therapeutic device. Deciding otherwise could in some cases place an undue burden on operators/licensees. (This is particularly the case for devices that use radioactive material for therapy purposes, and integrated on-board x-rays for treatment positioning and verification).
2. Non-human use, pre-clinical cell-irradiation and animal-irradiation systems are not well-addressed under current regulations. Proposed revisions/replacements should address these devices as a class of devices separate from "analytical x-ray systems".

A revision or replacement of the regulations with attention to consistency and addressing recent developments in radiation delivery technology will lower the cost of compliance for licensees and operators and will ultimately accrue to the benefit of public safety and therapeutic effectiveness.