1 ) A method of planning and delivering a clinical radiation treatment, comprising the steps of: (a) defining 3-dimensional volumes-of-interest (VOIs) corresponding to clinically salient targets or organs-at-risk within the patient, (b) specifying for each 3-dimensional VOI a clinically advantageous radiation dose distribution, (c) generating an initial set of estimated treatment parameter values, (d) calculating the radiation dose distribution that would result from said estimated treatment parameter values, (e) calculating the value of an objective function defined using a similarity measure between said calculated radiation dose distribution and said clinically advantageous radiation dose distribution, (f) calculating the mathematical gradient of said objective function with respect to said estimated treatment parameter values, (g) updating said estimated treatment parameter values using said gradient such that said similarity measure is improved, (h) repeating steps (d) through (g) until estimated treatment parameter values have reached a defined criteria for acceptability; (i) delivering treatment using final estimated treatment parameter values and a suitable clinical radiation generation device; whereby the final estimated treatment parameters produce a radiation dose distribution substantially similar to said clinically advantageous radiation dose distribution; whereby a clinically optimal radiation treatment plan is delivered.