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Editorial |
Department of Surgery and Molecular Oncology, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
"Why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye?"
Gospel according to St Matthew Chapter VII verse 3 Authorised Version (1611)
The paper by Nisbet and Cocker in this issue of the British Journal of Radiology [1] provides an interesting insight into the application of the Ionising Radiation (Medical Exposure) Regulations (IR(ME)R) to radiotherapy. Here we all are: demand is increasing at 5% per annum, resources are not really keeping up with demand [2], the technological demands of radiation treatment delivery are becoming increasingly complex, we are integrating radiotherapy itself into complex treatment schedules, and the introduction of the European working time directive and the new consultant contract will further deplete effective staffing levels, and what would an IR(ME)R inspector demand? That we use time and effort to produce, at the end of treatment, a dose summary record that would include "an assessment of dose from portal verification imaging and simulator and CT sessions" [1]. A radical dose of radiotherapy is typically in the range 45 Gy to 65 Gy. Even using CT simulation, the dose to the patient from simulation is less than 0.06 Gy [3]: less than 0.2% of the prescribed dose. The sheer irrationality of the inspectors' demand prompted a careful re-reading of IR(ME)R [4] and the accompanying guidance [5] to see whether such a request could be justified. If guidance and regulations are to be used as a justification for picking nits, then a nit-picking approach to the legislation itself is entirely reasonable.
A striking feature of IR(ME)R, and, more particularly, the accompanying guidance, is that they are quite clearly written with the diagnostic uses of radiation in mind. The impression is that the references to therapeutic uses of radiation are a bit of an afterthought. The result is an unsatisfactory legislative attempt to ride two horses at the same time. Ionising radiation can be used for imaging, it can also be used for treatment. Air rifles and field artillery both fire projectiles – it would be a nonsense to try to cover their use under a single piece of legislation.
An outstanding example of the confusion caused by the yoking together of the diagnostic and therapeutic uses of radiation is the vocabulary used to describe the professional roles involved. "Referrer", "practitioner" and "operator" makes perfect sense as a sequence in diagnostic imaging. It makes less sense in radiotherapy: particularly when, in a surprising example of action-at-a-distance, a practitioner, by authorizing an exposure, becomes an operator (Guidance 8.7.1 "any person who authorises an exposure becomes an operator by virtue of doing so"). So who am I? It would appear that I am simultaneously a referrer (I have requested radiotherapy for a patient), a practitioner (I have prescribed radiotherapy) and an operator (I have authorized an exposure). In all of these roles I am expected to sign documents. When I request a planning CT scan I physically sign the same form in three different places: as a request, as a justification for that request and to authorize the exposure. My signature is a devalued currency. Current procedures demand that I sign my name 12 times so that a patient can be treated with 5 fractions of pre-operative radiotherapy for rectal cancer.
The regulations sensibly, but perhaps unhelpfully, duck the issue of practice standards: "justification of types of practice is not addressed" (Guidance 2.2). Consider palliative radiotherapy. Practice varies widely: some radiotherapists would treat a bone metastasis with an 8 Gy single fraction, others might prescribe 30 Gy in 10 fractions. The regulations are concerned with whether the 30 Gy is optimally delivered, not with whether or not it should have been prescribed in the first place. Thus the regulations, when it comes to treatment, happily embrace a greater than three-fold variation in exposure to individuals.
There are puzzling discrepancies between the regulations and the guidance, and some of these differences have implications for radiotherapy (Table 1
). The guidance sensibly requests that under-dosage be reported: but surely, had the regulations been drafted with radiotherapy in mind, this would have been a statutory requirement. The guidance fails to mention that "radiotherapeutic procedures" are exempt from the requirement to keep doses arising from the exposure as low as reasonably practicable. In theory, under the terms of the guidance (but not the regulations proper), a Local Research Ethics Committee (LREC) would have the power to insist on an alteration of the dose of radiotherapy in a study that already had Multicentre Research Ethics Committee (MREC) approval. I am not certain that all LRECs would have the expertise to recognize that, in terms of biological effect, a dose of 30 Gy as a single fraction is higher than a dose of 45 Gy in 25 fractions. This aspect of the guidance could, if LRECs chose to exert their apparent rights, lead to some interesting anomalies in future clinical trials.
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So what is wrong with IR(ME)R? The problem is the inbuilt structural flaw. These regulations should never have been expected to cover both the diagnostic and the therapeutic uses of ionising radiation. Each needs its own specific regulations. By acknowledging the differences between the two uses of radiation we would improve the clarity of the legislative framework for each.
To return to my first concern, could I find any justification within IR(ME)R for the inspectors' demand regarding simulator dose etc.? No I could not. Under regulation 7(1), "radiotherapeutic procedures" are specifically exempted from the "as low as reasonably practicable" requirement. "Radiotherapeutic" is defined as "pertaining to radiotherapy" – simulation, CT scanning and portal imaging all pertain to radiotherapy and therefore should be considered as exempted procedures. We should not concern ourselves unduly with the motes and should, instead, concentrate on the beams.
Received for publication December 5, 2003. Accepted for publication January 6, 2004.
References
This article has been cited by other articles:
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  E G A Aird Second cancer risk, concomitant exposures and IRMER(2000) Br. J. Radiol., December 1, 2004; 77(924): 983 - 985. [Full Text] [PDF]
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R M Harrison Second cancers following radiotherapy: a suggested common dosimetry framework for therapeutic and concomitant exposures Br. J. Radiol., December 1, 2004; 77(924): 986 - 990. [Full Text] [PDF]
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