# Gonad Dose Assessment of Patients Undergoing Pelvic Radiotherapy
## 2 Methods  
Given the retrospective nature of this study, special attention was paid to minimize selection bias and ensure data consistency. The inclusion criteria were (i) age \(\leq\) 45 years at the time of treatment; (ii) diagnosis of rectal or gynecological tumors; (iii) treatment with external beam radiotherapy between 2014 and 2023; (iv) the use of 3 DCRT, IMRT, and VMAT techniques; and (v) availability of complete planning using Computed Tomography (CT) images and medical records in the institutional systems. The study aimed to reflect real-world clinical practice by including all eligible patients during the study period, thus enhancing external validity and reducing the risk of selection bias. No patients were excluded.  
For all patients, the clinical history, diagnosis, treatment plan, and discussion of FP or family planning were analyzed using the SCIInico Hospitalar Evolutionary Information System, version 2.8, developed by the Shared Services of the Ministry of Health. The technique, positioning, and fractionation of the radiation treatment were collected using the ARIA Oncology Information System, version 16.1, from Varian Medical Systems (Palo Alto, CA, USA). Despite being very radiosensitive, the ovaries are not typically considered to be organs at risk in pelvic radiotherapy. However, with improvements in irradiation techniques and the possibility of using Magnetic Resonance Imaging (MRI), their contouring is recommended, mainly in younger patients [22]. According to the literature, the appearance of the ovaries changes with age and the patient's hormonal status. During reproductive years, ovarian identification is facilitated by the presence of follicles but this becomes more challenging as patients age [23]. The patients did not have their gonads contoured and the automatic segmentation systems currently available in the department do not include contours for the ovaries or testicles. For this reason, it was necessary for each patient's planning CT scan to be manually contoured using Eclipse Treatment Planning Software, version 16.1, from Varian Medical Systems (Palo Alto, CA, USA). To reduce interobserver variability in the dose assessment, all gonadal delineations were manually performed by a radiation oncologist and a radiation therapist, both experienced in pelvic anatomy, and supported by MRI fusion [24]. Following this, the maximum and mean doses to both the right and left ovaries, as well as the testicles, were calculated and analyzed. The dose constraints taken into account in our department were from the Dose-Volume Constraints for Organs at Risk in Radiotherapy (CORSAIR): An All-in-One Multicenter-Multidisciplinary Practical Summary project, including radiation oncologists, medical physicists, and radiologists, as shown in Table 1[25].  
The statistical analysis was performed using IBM SPSS Statistics software, version 29.0.2, for Microsoft Windows. Results were considered to be statistically significant at a \(p\)-value of \(<\)0.05. To test the data normality, the Shapiro-Wilk test was used. The Wilcoxon test was used to compare the maximum and mean doses between the left and right testicles,as well as the left and right ovaries, because the normality assumption was not met. The Mann-Whitney test was used to compare the 3 DCRT and VMAT techniques and to evaluate differences between females who underwent ovarian transposition and those who did not.