[External exposure of hot cell operators in nuclear medicine].

Purpose: The coming into effect of decrees No. 626/94, 242/96 and 230/95 has once again brought out the problem of the radiation exposure of hot cell operators in nuclear medicine.

Material And Methods: With regard to the activity of the Division of Nuclear Medicine of the Istituto Nazionale Tumori in Milan, a map has been produced of the radiation fields in the hot cell in- and outside the working station by measuring the rate of exposure and evaluating the radiation energy using film dosimeters in multifilter containers.

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.

Effect of ionizing radiation on cell-cycle progression and cyclin B1 expression in human melanoma cells.

In the present study we investigated the effect of gamma-irradiation (2.5 and 10 Gy) on cell-cycle progression of a human melanoma cell line, M14, characterized by a moderate radiosensitivity (SF2 = O.5).

Potential and limitations of magnetic resonance imaging for real-time monitoring of interstitial laser phototherapy.

Rationale And Objectives: Magnetic resonance (MR) imaging has been suggested as a method to monitor interstitial laser phototherapy (ILP) in deep tissues. Unfortunately, a reliable relation between temperature and MR parameters has not yet been demonstrated. In this study, we examined whether such a relation exists and whether MR imaging can measure absolute temperature or temperature changes.

In vivo spectrophotometric evaluation of neoplastic and non-neoplastic skin pigmented lesions. III. CCD camera-based reflectance imaging.

Reflectance spectroscopy, which allows an objective evaluation of the color of surfaces, has recently been proposed as a useful tool to discriminate cutaneous melanoma from other pigmented cutaneous lesions. A novel spectrophotometric system based on the use of a charge coupled device camera provided with a set of interference filters has been developed to acquire images of cutaneous pigmented lesions at selected wavelengths ranging from 420 to 1040 nm. For each filter, an image was captured, digitized by a frame grabber and stored in a personal computer to perform off-line data handling.

[Design, development, and dosage control of individual compensatory filters for 6 MV X-ray radiotherapy].

An automated system for the design and manufacturing of individual compensators has been implemented. The system based on computed tomography enables 3D compensation of missing tissue and tissue heterogeneities. The relationship between Hounsfield numbers and electron densities was obtained empirically.

Dose-response curve slope improvement and result reproducibility of ferrous-sulphate-doped gels analysed by NMR imaging.

Ferrous sulphate gel analysed by relaxation time measurements with NMR imaging is considered a useful dosimeter for 3D determinations of absorbed dose. A protocol for the gel preparation with agarose SeaPlaque that leads to a dosimeter with very high dose sensitivity is described. The dose-response curve slope is about 0.

Ex vivo optical properties of human colon tissue.

Using a spectrophotometer equipped with an internal integrating sphere, the absorption (mu a) and the reduced scattering (microseconds') coefficients of ex vivo human colon tissues were evaluated from reflectance and transmittance measurements. Mu a and microseconds' varied from 47.7 to 1.

In vivo spectrophotometric evaluation of neoplastic and non-neoplastic skin pigmented lesions--I. Reflectance measurements.

Reflectance spectrophotometry from 400 to 800 nm on different cutaneous pigmented lesions, including primary and metastatic malignant melanoma, pigmented nevi, lentigo and seborrhoeic keratosis, has been performed by using an external integrating sphere coupled to a spectrophotometer. Measurements show that reflectance spectra of the different lesions manifest dissimilar patterns, particularly in the near IR region. Comparison of reflectance of nevi with that of malignant melanomas results in a highly significant difference (P less than 10(-6)) between the two samples.

[Use of fast electrons in oncologic therapy. More than a decade's experience].

Criteria of choice in the utilization of fast electrons in radiotherapy on the basis of 2400 cases and 13 years of experience in the radiotherapy department of Cancer Institute in Milan are discussed. In the opinion of the authors fast electrons represent the most rational treatment to homogenize or differentiate the dose distribution according to space as a complementary technique after first time treatments by different ionizing radiation. Authors demonstrate also that fast electron treatment is the most rational technique for metastases in the retina and for recurrence of rhinopharynx cancer.

Quality control of a hyperthermia system.

Characterization of the applicators, of the thermometers and of the cooling (bolus) system of hyperthermic apparatus must be made before starting hyperthermic treatment and also starting with a frequency depending on the technical features of equipments that make up the whole system. This data gives the radiotherapist some useful parameters for the selection of applicators and general knowledge of the accuracy of the system.

Extinction and absorption coefficients and scattering phase functions of human tissues in vitro.

Optical properties of different human tissues in vitro have been evaluated by measuring extinction and absorption coefficients at 635- and 515-nm wavelengths and a scattering angular dependence at 635 nm. Extinction was determined by the on-axis attenuation of light transmitted through sliced specimens of various thicknesses. The absorption coefficient was determined by placing samples into an integrating sphere.

[Treatment technic and clinical dosimetry in whole-body irradiation].

At the Istituto Nazionale Tumori, Milan, total-body irradiation (TBI) is delivered by a 15 MV linear accelerator, with two lateral opposed beams. Maximum build-up at the skin is achieved by lateral slabs of perspex 3 cm thick. Attenuation filters or bolus are used for dose compensation, or reduction, to the head and lungs.

[Usefulness of gallium 67 in research into the need for radical cervical lymph node dissection in patients with head and neck carcinomas].

Fifty-nine patients with head and neck carcinoma were examined with 67Ga scintigraphy. All patients had undergone lymph node dissection of the neck. They were followed for a minimum of 2 years after the examination.

[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.

[The management of particle accelerators in radiotherapy].

In this multicentric survey, the management costs and the technical problems connected with the use of electron accelerators in Radiotherapy are studied. The data were collected by a proper questionnaire and concern 11/35 accelerators in use in Italy, in public hospitals, during the period 1982-1983. The average purchase cost of an accelerator was 1113 milions lire and the amortization cost is 111 milions lire per year.

[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.