engleski

Doses during pelvis X-ray examination – phantom measurements

The radiogram of the pelvis is an essential part in diagnostic of various pathological conditions. This examination is the starting point and often the follow up of the most degenerative conditions of bone structures and joints of the region. Apart from abnormalities and traumatic conditions it is of most value to evaluate rheumatic and degenerative diseases of the pelvic region. The aim of this study is to determine the ratio of doses measured on the surface of phantom in primary beam and on various organs inside the phantom during pelvis X-ray diagnostic. The ratio will serve to estimate the organ doses in patients and serves for risk assessment and evaluation of carcinogenic and genetic damage. The investigation was carried out on 150 kV Shimadzu CH-200M X-ray unit, the conditions of irradiation were the following: 83 kV, 100mA, 40 mAs. The doses were measured in the anthropomorphic RANDO phantom in several layers in the anatomical regions of the organs of interest. Thermoluminescence (LiF:Mg, Cu, P-TLD-100H and LiF:Mg, Ti - TLD-100) and radiophotoluminescent (GD-352M) dosimetry systems were used to measure the phantom dose. The doses were measured in 10 expositions with both dosimetry systems. The mean value of the doses measured on the surface of phantom for one radiogram measured with RPL and TLD was 0.48 (±5.45%) mGy. The obtained value satisfies the diagnostic reference level (DRL) proposed in national regulation Official Gasette 125/06 for pelvis irradiation. These ratios of doses measured in organs and doses measured at surface of the phantom were the following: spermatic cord 0.64, root of penis 0.69, prostate 0.31, urinary bladder 0.35, rectum 0.19, while the ratios for sigmoid-, descending-, transverse- and ascending colon were in the range 0.40-0.58. In the future doses will be measured during pelvic radiogram for 20-40 years old male patients with diagnosis of rheumatoid arthritis using RPL and TL dosimetry systems.

X-ray examination; pelvis; TLD; RPL; child phantom

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