Evaluation of "A" points as a dosimetric parameter in gynecological brachytherapy guided by three-dimensional images

León-Ramos L.G.; Guzmán-Calcina C.S.; Quenhua-Huapula R.A. · Gaceta Medica Boliviana (2023) · DOI: 10.47993/gmb.v46i2.793

Resumen

Objective: to assess whether the punctual dose prescription technique, point A, is adequate for dose estimation in CTV-HR using 3D gynecological brachytherapy. Methods: treatment plans were collected for 35 patients with stage IB2-IVA (140 fractions or treatment plans) cervical cancer treated between 2019 and 2021, whose prescribed dose was 28Gy in 4 fractions. Points A were reconstructed, the prescribed dose was normalized to 100% isodose to compare with the doses in CTV- HR(D90%). Results: the average dose absorbed at CTV-HR(D90%) was 88.82 ±2.53 Gy and when normalizing the isodose of 100% at point A, average dose at CTV-HR(D90%) was obtained. of 99.3±5.85Gy. This average dose variation to the CTV-HR(D90%) represented an increase of 18%, resulting in 80% of the treatments corresponding to 28 patients falling outside the acceptable variation of the EMBRACE II protocol and only 20% of the treatments corresponding to 7 patients are within the range of the acceptable variation of the protocol in question. Conclusions: the dose prescription technique at point A clinically translates into an overdose of tumor and healthy tissue (rectum, sigmoid, bladder and intestine).

Instituciones: Universidad Nacional Federico Villarreal