This research measured the entrance surface radiationdose to the gonadal region of male patients’ who were underwent the lumbarspine X-ray examinations and analyzed the testicular radiation doses with thepatients’ BMI.Male patients’ testicular region received highradiation dose in lumbar spine X-ray examination after hip, pelvis andabdominal X-ray examinations (Wall, et al., 2011). ESD is also high for alumbar spine examination (Aliasgharzadeh, et al., 2015). ESD vary with exposureparameters while exposure parameters vary with the patient body thickness, typeof the equipment, imaging method, FFD, image processing conditions and alsodifferent radiographic persons.
With applying of same conditions for a specificprojection, one radiographer will use minimum possible exposure factors whileanother person using the maximum possible exposure parameters for the sameexamination. According to the above circumstances researchers wereused same X-ray equipment (Shimadzu), imaging method (CR), 100cm FFD and16*43cm FOV with same exposure factors specified for the lumbar spine region ondigital radiographic unit (300mA,80kV,71mAs for AP and 300mA,80kV,80mAs forlateral). According to test results total mean testicularradiation dose varies from 41.
066µSv to 131.990µSv while the mean value was73.356µSv. Previous researchers said that the doses as low as 0.
15Gy willreduce the sperm count and doses greater than 0.5Gy and 6Gy will result absenceof living spermatozoa and permanent sterility, respectively (Amanda, et al., 1993).
With conversion of these values in to equivalent dose values, shows that thereis no possible effect on testes with our test results for temporary orpermanent sterility. BMI was selected as a variable to compare the patient testicularradiation dose in two lumbar spine projections. In this research 16.10 to 36.20BMI range was observed within the population with 23.47 mean value. Variationbetween above parameter and total testicular radiation dose, AP and lateral testicularradiation doses were analyzed separately.
According to the analyzed result lesspositive correlation was found between patient BMI and AP testicular radiation dose. Previous study conducted in Sri Lanka evaluatedthe testicular radiation dose during the KUB radiography also found the similarresult that there is a weak positive correlation between BMI and testicularradiation dose (Horadigala and Jayasinghe, 2014). In the present study, pearsoncorrelation test identified that the less negative significant correlationbetween testicular radiation dose in lateral projection and patient BMI whiletotal testicular radiation dose shows least negative correlation with patientBMI. Distribution of AP and lateral dose values, totaltesticular dose and BMI values were tested by normality test and determinedthat distribution of total testicular ESD, ESD in lateral and patient BMI werenot normally distributed (p<0.05).
Testicular radiation dose in APprojection was normally distributed with normality test. The result of this study shown that the meantesticular radiation dose in lumbar spine AP projection was 58.79µSv with34.05µSv to 79.99µSv dose range while mean testicular radiation dose in lumbarspine lateral projection was 14.
55µSv with 1.37µSv to 52.00µSv dose range. Froma simple calculation above two mean values, around 75% of testicular radiationdose reduction was achieved in lumbar spine lateral projection with respect to theAP projection. As a percentage, testicular dose reduction (72%) in lumbar spinelateral than the AP projection nearly equal to previous research done inIreland with 0.036mGy testicular AP dose and 0.0102mGy testicular lateral dose(conor, et al.
, 2009). The previous study prove that lumbar spine lateralprojection already receives the testicular dose reduction due the laterallocation of the iliac bone (conor, et al., 2009). Present study result(14.55µSv) also compatible with their results. According to the literature, research study done inIndia found that mean SRD to the testes from lumbar spine AP as 282.
29µGy in CRand 75.24µGy in DDR with 70% dose reduction in DR than CR while testes dosefrom lumbar spine lateral was 506.69µGy in CR and 96.02µGy in DR with 78% dosereduction with DR than CR (Priyankara, et al). Present study test values wasnot compatible with these values and it may be due to manual selection ofexposure factors by radiographer in CR system and Philip medical systemsautomatic exposure control (AEC) based factors select for the DR system. Theywere proved that with the use of AEC in DR system could reduce the patienttesticular SRD. Present study also used the AEC for select the exposureparameters and test results revealed that lower doses received by the testeswith Sri Lankan practice.
Another related research study on reduction ofradiation risks in patients underwent some X-ray examinations by using optimalprojections with monte-carlo mathematical calculation found that the 0.429mGymean absorbed dose with AP and 0.053mGy mean testicular absorbed dose withlumbar lateral projection received for standard sized patient with 178.6cmheight and 73.2Kg weight (Chaparian, et al., 2013).
Present study results weredeviate from these values and it may be due to use of different X-ray unit withdifferent exposure parameters and radiation field size. 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). Radiographicexaminations carried 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. Aresearch study on testicular radiation dose during the kidney ureter bladder (KUB)radiography in Sri Lanka discovered that, the mean testicular radiation doseduring the KUB examination was 28.
76µSvwhile minimum and maximum testicular radiation dose were 5µSv and88µSvrespectively. They were concluded that the testicular radiation dose shownpositive correlations with the BMI, weight, body thickness, mAs and kV while nocorrelation with the patients’ age (Horadigala & Jayasinghe, 2014)Arelated study was done at the digital radiography unit Ireland with ananthropomorphic phantom using TLD. The gonad exposure dose was measured whenthe lumbar spine region was irradiated with both AP and lateral patientorientations. Gonad dose received during AP and lateral patient orientationswere found to be 0.036mGy and 0.0102mGy respectively.
Further it was reportedthat, the gonad dose can be reduce by 42% with the use of tube side gonadshield and 36% dose reduction with wrap around apron during the AP orientationin male patients. But no significant dose reduction with lead shield in lateralprojection (Conor, et al., 2009)Asimilar study was done Manipal in India on comparison of SRD to the gonads bylumbar spine examination in AP and lateral projections using CR and DDR. Thosedoses evaluated with gender.
The mean SRD to the male gonads from lumbar APprojection were found as 282.29µGy inCR and 75.24µGy in DDR. In lumbar lateral projection 506.69µGy in CRand 96.02µGy in DDR were found as mean SRD to the malegonads.
They were concluded that SRD to the gonads from AP projection 70% lowerin DR than CR and 78% lower in DR than CR with lumbar spine lateral projection(Priyankara, Rahul and Nitika, 2017)A researchstudy on reduction of radiation risks in patients undergoing some X-rayexaminations by using optimal projections with a monte carlo program basedmathematical calculation in Iran discovered that 86% of dose reduction to thetesticles with postero-anterior (PA) position rather than the AP in lumbarspine X-ray. But significant gonad dose difference was not observed in rightand left lateral positions of lumbar spine X-ray examination. These researcheswere found that the mean absorbed doses to the testicles in AP, PA, leftlateral (LLAT) and right lateral (RLAT) lumbar spine projections in males0.429mGy,0.062mGy, 0.053mGy and 0.
049mGy respectively by using a solid state dosimeterwithout the patient presence (Chaparian, et al., 2013).Anotherstudy was performed to find the organ doses for common X-ray examinations onadult patients in the UK population by using both ICRP 60 and 103 publicationdetails. They were calculated that the 0.
014mGy testes dose for lumbar spine APand 0.0004mGy testicular dose for lumbar spine lateral patient orientation. Andthey were found that the 0.018mGy testes dose received for whole procedure(Wall, et al., 2011).Anotherresearch study was done to assess the image quality and individual organ dosesby using the computed radiography with AP versus PA positioning in lumbarspine.
Their result found that 19.8% of mean effective dose reduction canachieved with lumbar spine PA projection. Similarly absorbed dose reductionalso achieved with PA position by stomach (70.4%), colon (61.1%), testes(15.9%), ovaries (7.3%) and reminder tissues (33.2%) (Andrew and Enda., 2015)