INTRODUCTION: The aim of this study was to determine the reproducibility and accuracy of linear measurements on 2 types of dental models derived from cone-beam computed tomography (CBCT) scans: CBCT images, and Anatomodels (InVivoDental, San Jose, Calif); these were compared with digital models generated from dental impressions (Digimodels; Orthoproof, Nieuwegein, The Netherlands). The Digimodels were used as the reference standard. METHODS: The 3 types of digital models were made from 10 subjects. Four examiners repeated 37 linear tooth and arch measurements 10 times. Paired t tests and the intraclass correlation coefficient were performed to determine the reproducibility and accuracy of the measurements. RESULTS: The CBCT images showed significantly smaller intraclass correlation coefficient values and larger duplicate measurement errors compared with the corresponding values for Digimodels and Anatomodels. The average difference between measurements on CBCT images and Digimodels ranged from -0.4 to 1.65 mm, with limits of agreement values up to 1.3 mm for crown-width measurements. The average difference between Anatomodels and Digimodels ranged from -0.42 to 0.84 mm with limits of agreement values up to 1.65 mm. CONCLUSIONS: Statistically significant differences between measurements on Digimodels and Anatomodels, and between Digimodels and CBCT images, were found. Although the mean differences might be clinically acceptable, the random errors were relatively large compared with corresponding measurements reported in the literature for both Anatomodels and CBCT images, and might be clinically important. Therefore, with the CBCT settings used in this study, measurements made directly on CBCT images and Anatomodels are not as accurate as measurements on Digimodels.

• MeSH
• kefalometrie statistika a číselné údaje   MeSH
• lidé MeSH
• počítačová tomografie s kuželovým svazkem statistika a číselné údaje   MeSH
• počítačové zpracování obrazu statistika a číselné údaje   MeSH
• povrchové vlastnosti MeSH
• reprodukovatelnost výsledků MeSH
• software MeSH
• zobrazování trojrozměrné statistika a číselné údaje   MeSH
• zubní korunka (anatomie) anatomie a histologie   MeSH
• zubní modely * MeSH
• zubní oblouk anatomie a histologie   MeSH
• zubní technika otisková statistika a číselné údaje   MeSH
• zuby anatomie a histologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

INTRODUCTION: The process of fabricating physical medical skull models requires many steps, each of which is a potential source of geometric error. The aim of this study was to demonstrate inaccuracies and differences caused by DICOM to STL conversion in additively manufactured medical skull models. MATERIAL AND METHODS: Three different institutes were requested to perform an automatic reconstruction from an identical DICOM data set of a patients undergoing tumour surgery into an STL file format using their software of preference. The acquired digitized STL data sets were assessed and compared and subsequently used to fabricate physical medical skull models. The three fabricated skull models were then scanned, and differences in the model geometries were assessed using established CAD inspection software methods. RESULTS: A large variation was noted in size and anatomical geometries of the three physical skull models fabricated from an identical (or "a single") DICOM data set. CONCLUSIONS: A medical skull model of the same individual can vary markedly depending on the DICOM to STL conversion software and the technical parameters used. Clinicians should be aware of this inaccuracy in certain applications.

• Klíčová slova
• Additive-manufacturing, Bio-modelling, CBCT, DICOM, STL,
• MeSH
• algoritmy MeSH
• anatomické modely * MeSH
• design s pomocí počítače statistika a číselné údaje   MeSH
• kefalometrie statistika a číselné údaje   MeSH
• lebka anatomie a histologie   MeSH
• lidé MeSH
• mandibula anatomie a histologie   MeSH
• nosní dutina anatomie a histologie   MeSH
• orbita anatomie a histologie   MeSH
• počítačová tomografie s kuželovým svazkem statistika a číselné údaje   MeSH
• počítačové zpracování obrazu statistika a číselné údaje   MeSH
• povrchové vlastnosti MeSH
• radiologické informační systémy statistika a číselné údaje   MeSH
• sinus maxillaris anatomie a histologie   MeSH
• software MeSH
• zobrazování trojrozměrné statistika a číselné údaje   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

The purpose of this study was to compare two different styles of prostate IGRT: bony landmark (BL) setup vs. fiducial markers (FM) setup. Twenty-nine prostate patients were treated with daily BL setup and 30 patients with daily FM setup. Delivered dose distribution was reconstructed on cone-beam CT (CBCT) acquired once a week immediately after the alignment. Target dose coverage was evaluated by the proportion of the CTV encompassed by the 95% isodose. Original plans employed 1 cm safety margin. Alternative plans assuming smaller 7 mm margin between CTV and PTV were evaluated in the same way. Rectal and bladder volumes were compared with initial ones. While the margin reduction in case of BL setup makes the prostate coverage significantly worse (p = 0.0003, McNemar's test), in case of FM setup with the reduced 7 mm margin, the prostate coverage is even better compared to BL setup with 10 mm margin (p = 0.049, Fisher's exact test). Moreover, partial volumes of organs at risk irradiated with a specific dose can be significantly lowered (p < 0.0001, unpaired t-test). Reducing of safety margin is not acceptable in case of BL setup, while the margin can be lowered from 10 mm to 7 mm in case of FM setup.

• MeSH
• adenokarcinom radioterapie   MeSH
• celková dávka radioterapie MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádory prostaty radioterapie   MeSH
• plánování radioterapie pomocí počítače MeSH
• počítačová tomografie s kuželovým svazkem statistika a číselné údaje   MeSH
• radioterapie řízená obrazem * MeSH
• senioři MeSH
• staging nádorů MeSH
• zaměřovací značky pro radioterapii * MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH