RE: Model estimate of dose

From: Johan.Rosenborg@astrazeneca.com Subject: RE: [NMusers] Model estimate of dose Date: Wed, December 8, 2004 6:07 am Nick, Thank you for your prompt reply! The gamma camera is calibrated in such a way that it measures the total AMOUNT of radioactivity in the same units as the actually administered dose, corrected for decay of the tracer during the course of the experiment. The string you suggest seems to be exactly what I need - if you have time, some additional crucial technical follow-up questions: 1) The data file: shall I enter a unit dummy-dose under AMT at time zero in conjunction with administration via the lungs (CMT=3)? 2) The model file: how do I assign the dose based on the estimate of "DOSE" in your string and incorporate it in an ADVAN8-based model as specified below? . . . . $SUBROUTINES ADVAN8 TOL=4 $MODEL COMP=(DEFOBS1) ; plasma COMP=(PERIPH1) ; peripheral cmt COMP=(DEFOBS2) ; lung $PK ;--------------------------------------------------------------------------- - ;SYSTEMIC PK ;--------------------------------------------------------------------------- - CL=THETA(1)*EXP(ETA(1)) K12=THETA(2)*EXP(ETA(2)) K21=THETA(3) S1 =THETA(4)*EXP(ETA(3)) K10=CL/S1 K31=THETA(5)*EXP(ETA(4))) ;--------------------------------------------------------------------------- - $DES DADT(1)=K31*A(3)-(K12+K10)*A(1)+K21*A(2) DADT(2)=K12*A(1)-K21*A(2) DADT(3)=-K31*A(3) ;--------------------------------------------------------------------------- - $ERROR . . . . / Johan > Johan Rosenborg > AstraZeneca R&D Lund > Experimental Medicine, S-221 87 Lund, Sweden > Tel: +46 46 33 65 99 Fax: +46 46 33 71 91 > E-mail: johan.rosenborg@astrazeneca.com