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Charleen Byrd
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1 brochure DISO fronte.jpg Locandina commerciale

2 Following the EURATOM 97/43 recommendation, since 2000 is operative in Italy the law D.L.vo 187/00 about the radioprotection of the patients undergone at medical radio exposition. In radiotherapy the number of Quality Controls is increasing as function of the treatment complexity and in some cases the workload is responsible of their partial absence. Moreover in this field severe incidents have been recently reported by the media.

3 Tumor Control Probability

4 Opinion of many physicists is that a control during the treatment using a dedicated software for the in-vivo dosimetry (IVD) could reduce dosimetric errors. This mean a major presence of physicists during the radiotherapy treatment execution, where actually there is a general absence of this professional component. Moreover the IVD is one of the best ways to gain experience to prevent errors when introducing new radiotherapy techniques.

5 All the current IVD supply estimations of the real delivered doses in patient. Indeed even the more complex clinical IVD procedures use initial reference CT scans (used for the plan) to reconstruct the x-ray fluence to use in a second step for the recomputation of the dose in the same reference CT scans. Then if the patient s shape or setup are changed, the reconstructed fluence is not accurate and so the reconstructed doses in the patient. Only a wide-spread use of image guided radiation therapy could assure more accurate daily dose distributions, but also higher doses at normal tissues and time consumed. For these reasons it is our opinion that accually, IVD tests in quasi real time can supply these useful clinical warnings to activate quality controls needed to remove the causes of errors.

asi-epids Parma Azienda Ospedaliera Universitaria Firenze Centro Oncologico Fiorentino Viterbo Ospedale Belcolle Roma

6 THE DISO PROGET, SUPPORTED BY ISTITUTO NAZIONALE di FISICA NUCLEARE INFN, AND UNIVERSITA CATTOLICA S.C. ROMA, INTEND TO DEVELOPE SOFTWARE FOR THE IN-VIVO DOSIMETRY CONTROL USING asi-epids Parma Azienda Ospedaliera Universitaria Firenze Centro Oncologico Fiorentino Viterbo Ospedale Belcolle Roma Università Cattolica Roma Campus Biomedico Campobasso Fondazione Giovanni Paolo II Rionero in Vulture Ospedale Oncologico Regionale CROB Cagliari Presidio Oncologico Businco website:

7 Staff of physicists Associated at INFN for the DISO Project website: ommerciale

8 DISO AIMS Easy implementation on linacs Varian, Elekta e Siemens The tests can be obtained in quasi real time due to the interfacing with the R&V of the Center

9 brochure DISO fronte.jpg Locandina commerciale

10 THE SOFTDISO-3DCRT SUPPLIES TWO TESTS: 1) The first test is the ratio between the reconstructed dose at the isocenter point, and that planned by TPS R = Diso/ Diso,TPS acceptance criteria: 0.95 R 1.05

$at the first fraction and the others obtained during the successive fractions.$ This is a suitable tool to find causes of incorrect beam delivery

11 2) The second test is a analysis test between a reference EPID image acquired at the first fraction and the others obtained during the successive fractions. This is a suitable tool to find causes of incorrect beam delivery reproducibility. reference current distribution image image of points in disagreement P <1

The reference EPID image (REI) is selected only if 1) it

$fraction therapy using Portal Visual Inspections; 2) the$ The analysis (Low et al.

supplies the agreement between the REI signal and that on

12 The reference EPID image (REI) is selected only if 1) it is verified the good patient setup, generally at the first fraction therapy using Portal Visual Inspections; 2) the ratio R is within the acceptance criteria of 5%. The analysis (Low et al. 1998) is determined for each pixel of the 2D-image and supplies the agreement between the REI signal and that on the current image with an acceptance criteria of 5% and a distance-to-agreement 3 mm. A perfect agreement means a percentage of points P <1 = 100% (with <1). Our experience suggests a pass-rate with P <1 90% and a mean value < 0.5

13 The acceptance criteria of all the dosimetric indexes : Acceptance-criteria: 0.95 R 1.05 Acceptance-criteria of 5% and a distanceto agreement 3 mm for P <1 and -mean value can be changed in the SOFTDISO-3D-CRT by the user

Abstract: A National Project for the in-vivo dosimetry in radiotherapy: first results

Abstract: A National Project for the in-vivo dosimetry in radiotherapy: first results A.Piermattei 1, L. Azario 1, S. Cilla 2, A.Fidanzio 1, F.Greco 1, M.T.Russo 3, S. Zucca 4 1 Istituto di Fisica e Unità