Medicalradiography is one of the widely performed diagnostic procedure for livingbeings in medicine. With the development of technology for imaging and diagnosethe conventional X-ray, fluoroscopy, dual energy X-ray absorptiometry (DEXA), computedtomography (CT) and magnetic resonance imaging (MRI) modalities are commonlybeing use. But due to the availability and cost effects in Sri Lanka conventionalX-ray comes first line in diagnostic imaging methods. Except MRI all abovemedical imaging modalities use the X-rays.
Inconventional X-rays, X-ray beam generated passes through the patient body tothe imaging plate and produce a static image. To produce the image conventionalfilm-screen, computed radiography (CR) or direct digital radiography (DDR)technology are using. Patient radiation dose depends on the exposure parametersset by the radiographer. It varies according to the patient body thickness,beam angulation, positioning.
Lumbarspine is a recently requested X-ray examination with its two basic views from eachpatient. It contributes highest collective dose among the conventional X-rayprocedures (Gershan V et al., 2010) and indirectly irradiate the patients’reproductive organs (Andrew and Enda, 2015). There is a susceptibility toreceive some amount of scatter radiation dose to the gonads (testes). Because ofthe patient’s reproductive organ is situated in close proximity to image fieldduring these examination (Conor, et al., 2009). Rapidlydividing, undifferentiated cells in tissue are most sensitive to the radiationeffect according to the Bergonie Tribondeau law (Hall E.
J., 2006). So the humaneye lenses, thyroid, gonadal region (testes and ovaries) are more sensitive toradiation than rest of the organs. Gonad is more radiosensitive organ with hightissue weighting factor (WT=0.08) (Vahid, et al., 2015). Theradiation dose received by the testes can be measured by using dosimetricquantity called entrance surface dose (ESD). The ESD is the measure of theradiation dose that is absorbed by the skin as it reaches the patient which isdirectly measurable dose quantity byusing athermoluminescent dosimeter (TLD) or the dosimeter with the unit of mGy (Murphy.
,2017).Radiationmay cause changes in the molecular structures of the cells and there will bebiological effects whether the radiation level is small or large. There are twotypes of biological effects called deterministic and stochastic (ICRP 103,2007). Deterministic effect has a practical threshold level in dose and theseverity of the effect increase with dose above this threshold level. If thisthreshold is not exceed effect will not be seen. In stochastic effects there isno threshold dose and probability of the radiation effect increases with dose.Probability of carcinogenesis or heritable effects increases with dose instochastic effects, but skin erythema, infertility, cataracts like symptomscannot be seen until they reach the threshold level (Hall and Giaccia., 2012).
Malegonad (testes) is situated superficially on the body between the legs andconsist of two testicles. Each testicle about 5cm long with scrotum coveringand has egg shaped appearance. Produce the male hormones and sperms. Immaturegerm cells in testicles called spermatogonia.
Differentiating spermatogonia arevery radiosensitive (Amanda, et al., 1993).Radiationdoses as low as 0.15Gy result the diminished sperm count (oligospermia) afterlatent period of about 6 weeks. Doses greater than 0.5Gy result in absence ofliving spermatozoa (azoospermia). Its recovery begins within one year afterdoses of less than 1Gy but requires 2-3.
5 years after a dose of 2Gy. The dosesin excess of 6Gy needed to result permanent sterility (Amanda, et al., 1993). Radiographic examinationscarried out with both benefits and risk. According to the internationalcommission on radiological protection (ICRP) publications there are three mainradiation protection principles. Due to the justification principle patient receivesmore benefits than risk. Radiation protection optimization principle says it isnecessary to decrease the patient receive doses in medical radiography as lowas reasonably achievable (ALARA).
With the individual dose limitation principle,dose to individuals should not exceed the limits recommended for theappropriate circumstances. It will prevent the deterministic effects and reducethe risk of stochastic effects to an acceptable limits.