ESTRO 2023 - Abstract Book

S2100

Digital Posters

ESTRO 2023

Results We have observed that the use of the NTO with a high priority improves the dose gradient beyond the PTV independently of D max and its priority. Conversely, the use of a low D max, independently of the priority assigned, has a negative impact on the dose gradient. The worsening of the gradient is more affected by the use of a D max, than by the priority on the NTO (Figure 2 a ). As expected, the use of a D max objective reduces the mean dose to the ITV, but this reduction occurs even with low priorities, and it is maintained almost constant with increasing priorities. The presence of fluence peaks also increases with lower values of the D max objective. When evaluating D max strength we see that this effect is true for the cases when D max priority is zero, as soon as the D max priority is increased the fluence peaks appear and remain almost constant (Figure 2 b ).

Conclusion Although the use of D max in the optimization in lung SBRT may help to deliver more congruent doses to the ITV among different centers or patients, its use has a negative impact on the dose gradient and the magnitude on fluence peaks.

PO-2333 Consensus spanish GINECOR group: Technical aspects in vulvar cancer radiotherapy. A delphy study

S. Cordoba Largo 1 , I. Rodriguez Rodriguez 2 , B. Belinchon Olmeda 2 , J. Anchuelo Latorre 3 , L. Couselo Paniagua 4 , I. Martinez 5 , D. Najjari Jamal 6 , E. Villafranca Iturre 5 , F. Celada Álvarez 7 , S. Rodriguez Villalba 8 , D. Farga 9 , C. de la Fuente Alonso 10 , S. García Cabezas 11 , M. Sánchez Belda 12 , P. Navarrete 13 1 Hospital Universitario Puerta de Hierro de Majadahonda, Radiation Oncology, Madrid, Spain; 2 Hospital Universitario La Paz, Radiation Oncology, Madrid, Spain; 3 3Hospital Universitario Marqués de Valdecilla, Radiation Oncology, Santander, Spain; 4 Hospital Clínico Universitario de Santiago, Radiation Oncology, Santiago de compostela, Spain; 5 Complejo Hospitalario de Navarra, Radiation Oncology, Pamplona, Spain; 6 Instituto Catalán de Oncología, Radiation Oncology,