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G Zonca

Publications and source records attributed to G Zonca.

26 records · Page 2Linked to original sources
PubMedDate not supplied

How thick should CT/MR slices be to plan conformal radiotherapy? A study on the accuracy of three-dimensional volume reconstruction.

AIM AND BACKGROUND: The aim of this experimental study was to correlate the thickness of acquired CT slices (2, 4 and 8 mm) or MR slices (4 and 7 mm) with the accuracy of three-dimensional volume reconstruction as performed by a commercially available radiation therapy planning system. METHODS: We used a cylindrical phantom, with a 15-cm diameter and 20-cm height, containing 5 spheres (12.7-31.8 mm diameter) of solid Plexiglas sunk in a 3% agar jelly solution. The phantom was scanned by the CT scan with 3 different slice thicknesses (2, 4 and 8 mm and a distance of 0 mm between the slices). Two different acquisition techniques (slice thickness of 4 and 7 mm with 0.8 and 1.4 mm slice distance, respectively) were compared in the MR study. The volume values calculated from measurements were compared with the known true volume values of the spheres. RESULTS: The average percentage volume difference between calculated and true values for the smaller spheres reconstructed with CT images 2 and 4 mm thick was generally less than 8%, whereas the error for volumes reconstructed with 8-mm-thick CT slices was more than 20%. For the large spheres, the error was generally less than 5%. The data produced by MR acquisition agreed with those obtained using CT sections. CONCLUSIONS: For targets less than 1.5 cm in diameter on our system it is reasonable to acquire CT images with the smallest thickness available. For targets between 1.5 and 3 cm, it seems sufficient to acquire the localization images with a slice thickness of 4 mm. For targets more than 4 cm in diameter, considering that with our radiation therapy planning system the time spent for manual contouring and for isodose calculation highly increased with the number of acquired images, we suggest that the acquisition of CT-MR slices 8-10-mm thick is totally adequate even for conformal radiotherapy treatments.

Image Processing, Computer-Assisted↗
PubMedDate not supplied

Imitating gesture learning in apraxic patients.

The authors studied a group of patients with ideomotor apraxia (IMA) to verify if these patients had some difficulties in gesture learning task in respect to non-apraxic patients and normal control subjects. The results show that learning difficulties are present in patients with IMA. Apraxic patients are not able to perform the gestures in the testing situation and non in everyday life; this fact would demonstrate that the motor pattern still exists in these patients but is inaccessible unless elicited by a strong stimulation.

Aged↗
PubMedDate not supplied

[3-dimensional automatic dosimetry in curietherapy].

Isodose curves can be viewed on multiple planes along with the radioactive implant and anatomical structures by projecting them on a video-display. The main options offered are the parallel projection of the implant selecting all the possible rotations, zooming and shifting, calculation of distance between two points of a selected plane, stereoscopic display.

Brachytherapy↗
PubMedDate not supplied

[Computerized dosimetry in curie therapy].

Automatic treatment planning for calculation of absorbed dose in curietherapy has been performed at the Istituto Nazionale Tumori of Milano on a routine for some years. The radioactive implant is reconstructed from orthogonal or stereo-roentgenograms, a tabular listing of doses or dose rates can be obtained on the grid of points and the isodose curves are automatically drawn with the projection of sources onto the selected planes of calculation by an interactive plotter.

Aged↗
PubMedDate not supplied

[The evaluation of aphasic deficits for the definition of a targetted logotherapeutic treatment].

The Aachener Aphasie Test (AAT) is the major German test for the diagnosis of aphasic disorders. The test is easy to use and is valid and reliable for the diagnosis of aphasia and its severity and to evaluate the recovery of the aphasic disorder after language rehabilitation. The AAT is, however, not sufficient to define cognitively sound logotherapeutic treatment. The use of tasks which are based on cognitive functional models allows the identification of specific processing levels that have been damaged by a cerebral lesion, and the definition of a focussed rehabilitation plan. In this paper, we will discuss the results of a cognitive neurolinguistic treatment in a patient who suffered of Broca's aphasia with agrammatism and phonological dyslexia.

Adult↗