{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,11]],"date-time":"2026-04-11T11:53:29Z","timestamp":1775908409697,"version":"3.50.1"},"reference-count":40,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2025,8,27]],"date-time":"2025-08-27T00:00:00Z","timestamp":1756252800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Applied Sciences"],"abstract":"<jats:p>Although the dosimetric advantages of rectal spacers in prostate cancer radiotherapy have been demonstrated in selected clinical trials, real-world data from routine clinical practice remain limited\u2014particularly within the Portuguese healthcare system. This study offers a detailed dosimetric comparison of Volumetric Modulated Arc Therapy (VMAT), with and without rectal spacer use, in a real-world patient cohort, aiming to assess the clinical relevance of spacer insertion under standard treatment protocols. A retrospective dosimetric evaluation was performed on 80 prostate cancer patients treated at a radiotherapy centre in southern Portugal. Patients were equally divided into two matched groups (n = 40): one receiving VMAT alone, the other receiving VMAT with hydrogel rectal spacer placement. Dose-volume histograms (DVHs) were analysed for the planning target volume (PTV) and key organs at risk (OARs). Standard dosimetric metrics, such as V50\u2013V75 for the rectum and bladder, V50 for femoral heads, and mean dose for the penile bulb, were assessed. PTV coverage was evaluated using conformity and homogeneity indices. Spacer use significantly decreased rectal dose exposure across all evaluated parameters without compromising PTV coverage or increasing dose to other OARs. These findings support routine rectal spacer applications to enhance treatment safety and patient outcomes.<\/jats:p>","DOI":"10.3390\/app15179414","type":"journal-article","created":{"date-parts":[[2025,8,28]],"date-time":"2025-08-28T10:29:18Z","timestamp":1756376958000},"page":"9414","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["The Impact of a Rectal Spacer in VMAT Dosimetry in the Treatment of Prostate Cancer"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-2717-9860","authenticated-orcid":false,"given":"Susana","family":"Oliveira","sequence":"first","affiliation":[{"name":"PhD Programme in Nanoscience and Biomedicine, University of Vigo, Circunvalaci\u00f3n ao Campus Universitario, 36310 Vigo, Pontevedra, Spain"},{"name":"Escola Superior de Sa\u00fade, Instituto Polit\u00e9cnico do Porto, Rua Dr. Ant\u00f3nio Bernardino de Almeida 400, 4200-072 Porto, Portugal"},{"name":"Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto Research Center, Portuguese Oncology Institute of Porto, Rua Dr. Ant\u00f3nio Bernardino de Almeida, 4200-072 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8933-3984","authenticated-orcid":false,"given":"Ruben","family":"Fernandes","sequence":"additional","affiliation":[{"name":"FCS-UFP, Faculdade de Ci\u00eancias da Sa\u00fade, Universidade Fernando Pessoa, Rua Carlos da Maia, 296, 4200-150 Porto, Portugal"},{"name":"FP-I3ID, FP-BHS, Universidade Fernando Pessoa, Pra\u00e7a de 9 de Abril 349, 4249-004 Porto, Portugal"},{"name":"RISE-Health, Escola de Medicina e Ci\u00eancias Biom\u00e9dicas, Universidade Fernando Pessoa, Funda\u00e7\u00e3o Ensino e Cultura Fernando Pessoa, Avenida Fernando Pessoa, 150, 4420-096 Gondomar, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3740-862X","authenticated-orcid":false,"given":"Pilar","family":"Baylina","sequence":"additional","affiliation":[{"name":"Escola Superior de Sa\u00fade, Instituto Polit\u00e9cnico do Porto, Rua Dr. Ant\u00f3nio Bernardino de Almeida 400, 4200-072 Porto, Portugal"},{"name":"FP-I3ID, FP-BHS, Universidade Fernando Pessoa, Pra\u00e7a de 9 de Abril 349, 4249-004 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2465-5143","authenticated-orcid":false,"given":"Jo\u00e3o","family":"Santos","sequence":"additional","affiliation":[{"name":"Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto Research Center, Portuguese Oncology Institute of Porto, Rua Dr. Ant\u00f3nio Bernardino de Almeida, 4200-072 Porto, Portugal"},{"name":"Medical Physics Service, Portuguese Oncology Institute of Porto, Rua Dr. Ant\u00f3nio Bernardino de Almeida, 4200-072 Porto, Portugal"},{"name":"Instituto de Ci\u00eancias Biom\u00e9dicas Abel Salazar (ICBAS), Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"}]},{"given":"Guy","family":"Vieira","sequence":"additional","affiliation":[{"name":"Joaquim Chaves Sa\u00fade | Cl\u00ednica de Radioncologia do Algarve, Rua da Associa\u00e7\u00e3o Oncol\u00f3gica do Algarve do, 8000-316 Faro, Portugal"}]},{"given":"Isabel","family":"Faria","sequence":"additional","affiliation":[{"name":"Escola Superior de Sa\u00fade, Instituto Polit\u00e9cnico do Porto, Rua Dr. Ant\u00f3nio Bernardino de Almeida 400, 4200-072 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6531-9301","authenticated-orcid":false,"given":"Norberto","family":"Pereira","sequence":"additional","affiliation":[{"name":"Psychology Service, Instituto Portugu\u00eas Oncologia do Porto (IPO PORTO), Rua Dr. Ant\u00f3nio Bernardino de Almeida 400, 4200-072 Porto, Portugal"},{"name":"NeuroCog-Centro de Reabilita\u00e7\u00e3o da Les\u00e3o Cerebral, Rua das Atividades Econ\u00f3micas, 2625-387 Lisboa, Portugal"},{"name":"Centre of Linguistics of the University of Lisbon (CLUL), Universidade de Lisboa, 1600-214 Lisboa, Portugal"},{"name":"RISE-HEALTH\u2014Polo de Gest\u00e3o, Escola Superior de Sa\u00fade, Instituto Polit\u00e9cnico do Porto, 4200-072 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,27]]},"reference":[{"key":"ref_1","first-page":"209","article-title":"Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries","volume":"71","author":"Sung","year":"2021","journal-title":"CA Cancer J. 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