radiography is one of the widely performed diagnostic procedure for living
beings in medicine. With the development of technology for imaging and diagnose
the conventional X-ray, fluoroscopy, dual energy X-ray absorptiometry (DEXA), computed
tomography (CT) and magnetic resonance imaging (MRI) modalities are commonly
being use. But due to the availability and cost effects in Sri Lanka conventional
X-ray comes first line in diagnostic imaging methods. Except MRI all above
medical imaging modalities use the X-rays.
conventional X-rays, X-ray beam generated passes through the patient body to
the imaging plate and produce a static image. To produce the image conventional
film-screen, computed radiography (CR) or direct digital radiography (DDR)
technology are using. Patient radiation dose depends on the exposure parameters
set by the radiographer. It varies according to the patient body thickness,
beam angulation, positioning.
spine is a recently requested X-ray examination with its two basic views from each
patient. It contributes highest collective dose among the conventional X-ray
procedures (Gershan V et al., 2010) and indirectly irradiate the patients’
reproductive organs (Andrew and Enda, 2015). There is a susceptibility to
receive some amount of scatter radiation dose to the gonads (testes). Because of
the patient’s reproductive organ is situated in close proximity to image field
during these examination (Conor, et al., 2009).
dividing, undifferentiated cells in tissue are most sensitive to the radiation
effect according to the Bergonie Tribondeau law (Hall E.J., 2006). So the human
eye lenses, thyroid, gonadal region (testes and ovaries) are more sensitive to
radiation than rest of the organs. Gonad is more radiosensitive organ with high
tissue weighting factor (WT=0.08) (Vahid, et al., 2015).
radiation dose received by the testes can be measured by using dosimetric
quantity called entrance surface dose (ESD). The ESD is the measure of the
radiation dose that is absorbed by the skin as it reaches the patient which is
directly measurable dose quantity by
thermoluminescent dosimeter (TLD) or the dosimeter with the unit of mGy (Murphy.,
may cause changes in the molecular structures of the cells and there will be
biological effects whether the radiation level is small or large. There are two
types of biological effects called deterministic and stochastic (ICRP 103,
2007). Deterministic effect has a practical threshold level in dose and the
severity of the effect increase with dose above this threshold level. If this
threshold is not exceed effect will not be seen. In stochastic effects there is
no threshold dose and probability of the radiation effect increases with dose.
Probability of carcinogenesis or heritable effects increases with dose in
stochastic effects, but skin erythema, infertility, cataracts like symptoms
cannot be seen until they reach the threshold level (Hall and Giaccia., 2012).
gonad (testes) is situated superficially on the body between the legs and
consist of two testicles. Each testicle about 5cm long with scrotum covering
and has egg shaped appearance. Produce the male hormones and sperms. Immature
germ cells in testicles called spermatogonia. Differentiating spermatogonia are
very radiosensitive (Amanda, et al., 1993).
doses as low as 0.15Gy result the diminished sperm count (oligospermia) after
latent period of about 6 weeks. Doses greater than 0.5Gy result in absence of
living spermatozoa (azoospermia). Its recovery begins within one year after
doses of less than 1Gy but requires 2-3.5 years after a dose of 2Gy. The doses
in excess of 6Gy needed to result permanent sterility (Amanda, et al., 1993).
carried out with both benefits and risk. According to the international
commission on radiological protection (ICRP) publications there are three main
radiation protection principles. Due to the justification principle patient receives
more benefits than risk. Radiation protection optimization principle says it is
necessary to decrease the patient receive doses in medical radiography as low
as reasonably achievable (ALARA). With the individual dose limitation principle,
dose to individuals should not exceed the limits recommended for the
appropriate circumstances. It will prevent the deterministic effects and reduce
the risk of stochastic effects to an acceptable limits.