PLANNING MANUALLY - Radiation Oncology: A Physicist's-Eye View - page 171

problems with the three abutting beams. This presentation has its
origins in the display of “images of regret” suggested by Shalev
et al . (1988).
Uncertainty in quantities depending on the dose distribution
One is also, of course, interested in the uncertainties in quantities
derived from the 3D dose distribution. This includes scalar quantities
such as D min , D near-min , D mean , D near-max , D max , and so forth for all VOIs,
and estimates of biophysical quantities such as TCP, NTCP, and
EUD. The uncertainty bounds in these quantities can be estimated
(in fact, probably over-estimated for the reason given above) by
computing their values from the lower- and upper-bound dose
distributions. An approach to estimating the uncertainty bounds of
DVHs has been presented by Niemierko and Goitein (1994).
T HE P ATIENT ' S -E YE V IEW
I have discussed the process of planning and delivering radiation
therapy as though it were exclusively the domain of the treatment
planner and the patient's physician. However, the patient is a vital
part of this process not just a passive recipient of the treatment. The
patient has to be involved in numerous aspects of the process.
Diagnosis and choice of treatment modality
Self-evidently, the patient's self-reporting (the history) is an impor-
tant element of diagnosis. The patient also can play a central role
in the choice of therapeutic modality. He or she may have quite
personal views on, say, organ preservation, which can sway the
choice of modality between, say, surgery and radiation therapy. It is
vital that the patient gives informed consent to the treatment decided
upon. For this, the patient must be fully informed. In my years of
working in a radiation therapy department, I have heard several
conversations in which the plan for the patient's therapy was being
presented to the patient by his or her physician. Too great a fraction
of these involved more of a lecture than a give-and-take conversation.
The patient's role in risk management
The balance between risks is central to treatment planning decisions.
Most notably, between local tumor control and normal tissue
complication probabilities, but also among the various normal tissue
complication probabilities since it is sometimes possible to spare
one organ at the expense of another. The patient may be a willing