Open AccessThe transition from conformal to advanced radiotherapy techniques in the treatment planning of gynecological cancer patients
Author(s) -
Borislava Petrović,
Olivera Ivanov,
Milana Marjanović,
Jelena Ličina,
Ivan Gencel,
Nemanja Golubovac
Publication year - 2022
Publication title -
vojnosanitetski pregled
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.123
H-Index - 19
eISSN - 2406-0720
pISSN - 0042-8450
DOI - 10.2298/vsp210520077p
Subject(s) - medicine , radiation therapy , nuclear medicine , dosimetry , radiation treatment planning , rectum , radiology , surgery
Background/ Aim. Transition from standard to highly conformal radiation therapy techniques, requires implementation of complex advanced dosimetry. The aim of the work was comparison of dosimetric parameters of 3DCRT and VMAT plan, as well as complications after treatment in relation to dosimetric parameters at gynecological cancer patients. Methods. Forty-nine gynecological cancer patients were included in the study. All patients were planned for 3D CRT, but due to unacceptable doses to organs at risk, treatment plans for IMRT or VMAT were generated for 21 patients. The patients were prescribed 50.4 Gy/28 fractions (4) and 45 Gy/25 fractions (45 patients). The coverage of PTV and doses to organs at risk were recorded. PTV margins were evaluated for both techniques according to the Van Herk formula. Results. ICRU 83 criteria were fulfilled in all 3DCRT /VMAT/IMRT plans providing optimal coverage of PTV. Doses to OARS: in average, the V45Gy in small bowel in IMRT/VMAT plans was four times smaller than the same of 3DCRT plans. The V45Gy of small bowels was in average 49.4cm3 in IMRT/VMAT plans, while in 3DCRT plans it was 211.6 cm3. In case of femoral head, significant reduction in V30Gy (10.8 % vs. 33.1%) and mean dose in case of IMRT/VMAT plans was recorded (30.4 Gy in 3DCRT vs 23.6 Gy). Rectum was planned with significantly lower dose in terms of V30Gy (79.5% vs 95.2%) in IMRT/VMAT plans. Bladder was better spared in VMAT plans in terms of V40Gy (51% vs. 91%), but maximum dose was higher in VMAT plans than in 3DCRT (50.1 Gy to 48.1 Gy in average). For all OARs there is statistically significant difference registered at p>0.05. Toxicities recorded in VMAT and 3DCRT patients include mainly radiation induced cystitis and enteritis. Patients treated with 3DCRT generally have longer recovery time. Homogeneity index was 0.11 for VMAT plans and 0.09 for 3DCRT plans. Conclusions. Analysis of dosimetric parameters revealed significant differences in normal tissue doses for same 3DCRT and VMAT patient, which confirmed necessity for implementation of advanced techniques for as many patients as possible.