ESTRO 2022 - Abstract Book

S1201

Abstract book

ESTRO 2022

Conclusion Our data show that reconstruction at 55 KeV is the sequence that provides a lower IOV in the contouring of PG and OARs, although the difference is not statistically significant. The higher IOV is observed in the basal CT scan, while the integrated use of the additional DECT reconstructions could reduce the IOV even if with greater time consuming. To our knowledge, this is the first study evaluating the role of DETC in IOV for PC and highlights the potentialities of DECT in improving the contouring of the PG and OARs

PO-1417 Role of MRI radiomics analysis and Pi-RADS score in prostate cancer.

A. Angrisani 1 , L. D'Alessandro 1 , R. Grassi 1 , V. Nardone 1 , E. D'Ippolito 1 , C. Guida 2 , A. Reginelli 1 , S. Cappabianca 1

1 "L. Vanvitelli" University of Campania, Precision Medicine - Radiotherapy Unit, Naples, Italy; 2 Ospedale del Mare, Radiotherapy, Naples, Italy Purpose or Objective Radiomics can provide quantitative features from medical imaging that can be correlated to clinical endpoints. The challenges relevant to the robustness of radiomics features have been analyzed by many researchers, as it seems to be influenced by acquisition and reconstruction protocols, as well as by the segmentation of the region of interest (ROI). Prostate cancer represents a difficult playground for this technique, due to the discrepancies in the identification of the cancer lesion and the various acquisition protocols. The aim of this study is to investigate the role of radiomics in prostate cancer detection and the correlation with Gleason score. Materials and Methods A homogeneous cohort of patients with a PSA rise that underwent multiparametric MRI imaging of the prostate before the biopsy was tested in this study. All the patients' images were acquired with the same MRI scanner, with a standardized protocol. The identification and segmentation of an MRI suspicious cancer lesion were done by two double-blinded Radiologists with great experience in prostate cancer (>10 years). After the segmentation, texture features were extracted with LifeX software. All the patients underwent random prostate biopsy procedures and the presence of prostate cancer, as well as the Gleason, was retrospectively collected. Texture features were then tested with intraclass coefficient correlation (ICC) analysis to analyze the reliability of the segmentation. The reliable features were then correlated with the presence of prostate cancer and with the Gleason score with Chi-Square analysis, with Bonferroni correction for multiple comparisons. Results Forty-four consecutive patients were included in the present analysis. In 26 patients (59,1%) the prostate biopsy confirmed the presence of prostate cancer, which was scored as Gleason 6 in 6 patients (13,6%), Gleason 3+4 in 8 patients (18,2), and Gleason 4+3 in 12 patients (27.3%). Chi-square analysis showed that only GLCM-Contrast DWI400 and GLCM-dissimilarity DWI400 were significantly correlated with both the presence of prostate cancer (respectively p:0,007 and p:0,012) and the Gleason score (respectively p:0,012 and p:0,024). Conclusion Despite issues of reproducibility, correlations with prostate cancer detection and Gleason score are still promising although we remark the need to further study the potential of MRI radiomics in prostate cancer in a clinical setting. 1 MAASTRO, Department of Radiation Oncology, Maastricht, The Netherlands; 2 MAASTRO, Radiation Oncology , Maastricht, The Netherlands Purpose or Objective Hyaluronic acid (HA) is one of the four commercialized implantable rectum spacers available on the market, besides hydrogel, saline filled balloon, and human collagen. These implantable rectum spacers are used to decrease rectal radiation dose in prostate cancer radiotherapy to avoid rectal complications after prostate cancer radiotherapy. However implantation of such devices are not risk-free: if such spacers are accidentally implanted in the rectal wall, might result in a chronic wound. Then it can take 3 to 9 months for such spacers to resolve. Furthermore, such a complication results in a significant treatment delay, since an immediate start of radiotherapy could increase the risk of fistula development. So, the feasibility to resolve such a spacer is of great interest in the community. To determine a dose response relationship of disintegration between a hyaluronic acid (HA) used in prostate cancer radiotherapy and hyaluronidase (HAS). Materials and Methods Five in-vitro prostate cancer models (SIM TM ) are applicated with 3 milliliter (ml) HA (Figure 1For dissolution varying doses of HAS were used: 6 ml, 3 ml, 1.5 ml, and 0 ml. One ml contains 150 International Units (IU). Each HAS was added with saline till the complementary amount of 6 ml. One phantom was solely implanted with a HA 3 ml acting as a control. Length, width and height were measured on different time points: 1 st day 4 times, 2 nd day 3 times, third day 2 times, and then once daily during one week, with a final measurement 2 weeks after implantation. PO-1418 Evaluation of Hyaluronic acid dissolution with hyaluronidase in an in-vitro prostate cancer model B. Vanneste 1 , L. Lutgens 2 , E. Van Limbergen 2