Ploidy and chromatin pattern analysis as an aid for cervical smear diagnosis.

In the present study we used computer-assisted microscopy to analyze the morphology of Feulgen-stained cell nuclei in cell populations obtained at the same time as routinely performed cervical smears and in the same way. We investigated in a series of 110 cases whether the quantitative morphonuclear description of cytological cervical samples is able to aid pathologists to distinguish between benign and more suspect premalignant lesions. For this task nuclear DNA content, nuclear morphometry (size and anisonucleosis level) and chromatin pattern-related parameters were compiled for each specimen enrolled in the database. A set of 32 normal and 17 high-grade squamous intraepithelial lesion (HSIL) specimens (with diagnostic confirmations) were selected as references and used to establish a discriminant model on the basis of cytometry-generated variables. This model was then used to score the remaining 61 cases in our series (including cases exhibiting benign cellular changes, squamous cells of undetermined significance, low-grade SIL and cancers). The results show that a model discriminating efficiently between normal and HSIL groups can be obtained by combining 5 quantitative features (1 DNA ploidy-related, 2 morphometrical and 2 chromatin texture features). A 97% specificity and an 88% sensitivity characterized the boundary so established. When applied to new cases, the model was in fact able to correct diagnoses for cases which had been down- or up-graded on the basis of the Bethesda system, and provided scores in accordance with histological control.

Correlation of patient skin doses in cardiac interventional radiology with dose-area product.

The use of X-rays in cardiac interventional radiology has the potential to induce deterministic radiation effects on the patient's skin. Guidelines published by official organizations encourage the recording of information to evaluate this risk, and the use of reference values in terms of the dose-area product (DAP). Skin dose measurements were made with thermoluminescent dosemeters placed at eight different locations on the body. In addition, DAP was recorded in 100 patients for four types of interventional radiology procedures. Mean, median and third quartile for these results are presented. Maximum skin dose values found were 412 mGy, 725 mGy, 760 mGy and 1800 mGy for coronary catheterization, coronary catheterization with left ventricle investigation, and percutaneous transluminal angiography without and with stenting, respectively. Median DAPs for these same procedures were, respectively, 5682 cGy cm2, 10,632 cGy cm2, 10,880 cGy cm2 and 13,161 cGy cm2. The relationship between DAP and skin dose was investigated. We found a poor correlation of DAP with maximum skin dose (r = 0.77) and skin dose indicator (r = 0.78). Using conversion factors derived from Monte Carlo simulations, skin dose distributions were calculated based on the measured DAPs. Agreement between the calculated skin dose distribution, using DAP values averaged over a group of patients who underwent coronary catheterization and left ventricle investigation, and the measured skin dose averaged over the same group of patients was very good. However, there were large differences between the calculated skin doses using the individual DAP data per patient and measured skin doses for individual patients (r = 0.66). Hence, calculation of individual skin doses based on the specific DAP data per patient is not reliable and therefore measuring skin dose is preferable.

Histological patterns in endometrial samples from perimenopausal women.

OBJECTIVE: Evaluation of endometrial histology patterns in perimenopausal women. METHODS: Endometrial biopsies (202) taken from perimenopausal women by suction curette were assessed by light microscopy. RESULTS: Out of 142 adequate specimens a total of 82 (57.7%) specimens could not be classified in the well-defined categories of the fertile period because of mixed histological patterns. Of the 142 specimens, 59 (41.5%) showed abnormal secretory endometrium, three (2%) disordered proliferative endometrium and 20 (14.1%) a mixture of non-secretory and secretory endometrium. CONCLUSION: The often used histological classification for endometrium, with well-defined regular patterns based on normal cyclic changes, often does not apply to endometrial tissue obtained from perimenopausal women due to a mixed pattern within one biopsy.

Monte Carlo modelling of radiotherapy kV x-ray units.

To obtain accurate information for absorbed dose calculations in water for kilovoltage x-rays, the photon spectrum, planar fluence and the angular distribution of the photons at the collimator exit of the x-ray unit have to be known. The only way to obtain this information is by Monte Carlo (MC) simulation. Compared with the situation for high-energy photons and electrons, where in recent years numerous papers have been devoted to MC modelling of complete clinical accelerator units, there is a lack of similar work for kV x-ray units. A reliable MC model for a kV x-ray unit would allow the output information to be used in a treatment planning system for regular and irregular treatment fields. Furthermore, with MC simulation, perturbation factors of dose-measuring devices, such as those specified in codes of practice, can be calculated. In this work, the MC code EGS4/BEAM was used to build realistic models of two complete x-ray units. The tungsten target, exit window, collimator, additional filtration and applicator were taken into account. For some aspects of the work, a comparison was made with the simulations from another MC code, MCNP4B. The contribution to the characteristic radiation from electron impact ionization and from the photoelectric effect of reabsorbed bremsstrahlung photons was studied. Calculated and measured photon fluence spectra in air and half-value layers for a Philips MCN410 tube were compared for several anode voltages and additional filtrations. Results from the two codes agreed well, and the agreement with measured spectra was found to be good for energies above 50 keV but rather less good below that energy. For a Siemens Stabilipan 2 Th300 x-ray tube, HVLs and dose distributions in water were compared with measurements for several clinical x-ray qualities. For most of the combinations of radiation qualities and applicators, good agreement was obtained, although there were also some cases where the agreement was not so good. Electron contamination and photon build-up at the water surface were studied using MC simulation. The influence of depth on the photon spectral distribution was investigated. Both EGS4/BEAM and MCNP4B, in their default versions, handle inadequately the production of characteristic x-rays. This was found to have only a minor influence on the calculated dosimetric quantities. Simulations with MCNP4B required the use of several variance reduction techniques in order to obtain results within reasonable calculation times.