131I INTERNAL CONTAMINATION AND COMMITTED DOSE ASSESSMENT AMONG NUCLEAR MEDICINE MEDICAL PERSONNEL

This study presents 131I thyroid activity measurements of 56 employees of the Department of Nuclear Medicine and Endocrine Oncology, Centre for Oncology in Gliwice. The research instrument was a whole-body spectrometer. In 44 out of 56 examined staff members, the determined 131I activity was found to be above the detection limit. The measured activities ranged from 6 ± 2 to 457 ± 118 Bq. The maximum estimated committed effective dose reached was 1.5 mSv/y. The results were compared with previous measurements conducted in another Polish nuclear medical unit. From this comparison, we can see that radiological safety among nuclear medicine personnel can be improved by appropriate work organisation. Reducing exposure of workers can be achieved by properly organised turnovers concerning the most vulnerable worksites. In addition, to lower the radiation risk, it is essential to comply strictly with the isolation regime for the patients.

Measurement of 131I activity in thyroid of nuclear medical staff and internal dose assessment in a Polish nuclear medical hospital

This paper presents results of 131I thyroid activity measurements in 30 members of the nuclear medicine personnel of the Department of Endocrinology and Nuclear Medicine Holy Cross Cancer Centre in Kielce, Poland. A whole-body spectrometer equipped with two semiconductor gamma radiation detectors served as the basic research instrument. In ten out of 30 examined staff members, the determined 131I activity was found to be above the detection limit (DL = 5 Bq of 131I in the thyroid). The measured activities ranged from (5 ± 2) Bq to (217 ± 56) Bq. The highest activities in thyroids were detected for technical and cleaning personnel, whereas the lowest values were recorded for medical doctors. Having measured the activities, an attempt has been made to estimate the corresponding annual effective doses, which were found to range from 0.02 to 0.8 mSv. The highest annual equivalent doses have been found for thyroid, ranging from 0.4 to 15.4 mSv, detected for a cleaner and a technician, respectively. The maximum estimated effective dose corresponds to 32% of the annual background dose in Poland, and to circa 4% of the annual limit for the effective dose due to occupational exposure of 20 mSv per year, which is in compliance with the value recommended by the International Commission on Radiological Protection.

Variation of counting efficiency in determination of 131I activity in the thyroid gland as a result of its position relative to the detector

The appropriate determination of the ¹³¹I which was absorbed into the human body, especially by thyroid, depends not only on individual features of each measurement subjects but also on reproducibility of their position or the thyroid’s position in the human neck. Possible uncertainties caused by changes of the thyroid position relative to detector were studied in a series of measurements. The research has shown that the dispersion of the results can reach up even to the level of 50 %.

Computer analysis of normal and basal cell carcinoma mast cells

BACKGROUND

Basal cell carcinoma (BCC) is the most frequently observed neoplasm of the human skin. Mast cells are regarded as important cellular elements of all organs and tissues of the human body. They are involved in many physiological and pathological processes, including inflammation and fibrotic changes observed in BCC. The aim of our study was to characterise in detail mast cells observed in BCC and normal skin on the basis of computer analysis techniques.

MATERIAL AND METHODS

Series of photographs obtained from histopathological biopsies of basal cell carcinomas from 18 patients, stained specifically for mast cells with Astra blue and nuclear red, were employed for the study. Control group consisted of series of photographs from normal skin obtained from 18 persons who underwent plastic surgery operations. All the photographs underwent digital computer analysis by means of a number of subroutines written in Delphi developed at the Technical University of Łódź.

RESULTS

Specific staining allowed for thresholding the image and subsequently mast cells were visualised as black objects on a white background. Those objects were then analysed in detail i.e. their geometrical features (area, perimeter, maximal diameter) were calculated. The employed image analysis techniques allowed for the differentiation and detailed characteristics of mast cells stained with Astra blue and nuclear red.

CONCLUSIONS

We observed that mast cells in BCC gathered mainly in fibrous stroma and were more numerous, had considerably larger area, longer perimeter and maximal diameter than normal skin mast cells.