PURPOSE: The soft tissue imaging in micro-CT remains challenging due to its low intrinsic contrast. The aim of this study was to create a simple staining method omitting the usage of contrast agents for ex vivo soft tissue imaging in micro-CT. MATERIALS AND METHODS: Hearts and lungs from 30 mice were used. Twenty-seven organs were either fixed in 97% or 50% ethanol solution or in a series of ascending ethanol concentrations. Images were acquired after 72, 168 and 336 h on a custom-built micro-CT machine and compared to scans of three native samples. RESULTS: Ethanol provided contrast enhancement in all evaluated fixations. Fixation in 97% ethanol resulted in contrast enhancement after 72 h; however, it caused hardening of the samples. Fixation in 50% ethanol provided contrast enhancement after 336 h, with milder hardening, compared to the 97% ethanol fixation, but the visualization of details was worse. The fixation in a series of ascending ethanol concentrations provided the most satisfactory results; all organs were visualized in great detail without tissue damage. CONCLUSIONS: Simple ethanol fixation improves the tissue contrast enhancement in micro-CT. The best results can be obtained with fixation of the soft tissue samples in a series of ascending ethanol concentrations.

• MeSH
• ethanol * MeSH
• kontrastní látky * MeSH
• modely u zvířat MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• plíce anatomie a histologie   diagnostické zobrazování   MeSH
• rentgenová mikrotomografie metody   MeSH
• srdce anatomie a histologie   diagnostické zobrazování   MeSH
• vylepšení obrazu metody   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Background: A favourable dose distribution has been described for proton beam therapy (PBT) of anal cancer in dosimetric studies. The relationship between dosimetric parameters in bone marrow and haematologic toxicity, treatment interruptions, and treatment efficacy has also been documented. There are only few references on clinical results of PBT for anal cancer. The primary objective of the retrospective study was to assess the efficacy of pencil beam scanning intensity-modulated proton therapy (PBS IMPT) in the definitive chemoradiotherapy of anal cancer. Secondary objectives were established to identify the risks of acute chronic toxicity risks and to assess colostomy rates. Materials and methods: Patients were treated for biopsy-proven squamous cell cancer (SCC) of the anus at initial or advanced stages. Eligible patients received PBS IMPT at a single institution. Treatment was administered in two volumes: 1-tumour with margins plus involved lymph nodes; 2-regional lymph node groups: perirectal (mesorectal), obturatory, inguinal, internal, external, and common iliac. The total doses of 57.5 GyE and 45 GyE, respectively, were administered in volumes 1 and 2 in 25 fractions, 5 fractions per week, respectively (a simultaneous integrated boost). Concomitant chemotherapy cisplatinum (CDDP) plus 5-FU or CDDP plus capecitabine was administered as per protocol. The treatment effect was assessed using DRE (digital rectal examination) and MRI (magnetic resonance imaging) within the follow-up period. Toxicity was scaled using CTCAE version 4.0 criteria. Results: 39 of 41 patients treated during the period of February 2014-August 2021 were eligible for analysis. All patients completed treatment, 76.9% without interruption. The median treatment time was 35 days (32-35). The median follow-up period was 30 months, 34 patients are alive to-date, 5 patients died prior to the date of analysis, and 2 deaths were unrelated to the primary disease. The 2-year overall survival, relapse-free survival, and colostomy-free survival were 94.2%, 93.8%, and 91.0%, respectively. Complete regression was achieved in 36 patients (92.3%), partial regression was achieved in 2 (5.1%), and immediate progression at end of treatment occurred in 1 patient (2.6%). Salvage resection was indicated for two patients in partial regression and due to severe chronic dermatologic toxicity. The grade 3 and 4 haematological toxicity rates were 7.7% and 5.1%, respectively. The most frequent non-haematological acute toxicities of grade 3-4 observed were dermatitis (23.1%), diarrhoea (7.7%), and dehydration (7.7%). Chronic toxicity emerged predominantly as skin atrophy/ulceration grade 2 (26.5%) and grade 3-4 (5.8%), and radiation proctitis grade 2 (38.2%) and grade 3 (2.9%). Discussion, conclusions: This single-institution study showed the high efficacy of PBS IMPT, achieving a high rate of complete regression. The haematological acute toxicity of grade 3-4 remained low; however, the impact of altered chemotherapy (CDDP instead of mitomycin C) remains unclear. The incidence of other acute toxicities shares similarity with photon therapy investigated in large studies. The acute toxicity completely resolved in all patients, had no lethal outcomes, and never resulted in the necessity for colostomy. By contrast, it was chronic toxicity, skin ulceration, perirectal fistulation, and fibrosis that resulted in salvage surgery and/or the need for a colostomy. A challenging question remains: to what extent can PBT prevent chronic toxicity? Longer follow-up remains necessary.

• Publikační typ
• časopisecké články MeSH