| PARTâ… Clinical study of DW-MRI to evaluate the influence ofIMRT on salivary glands of NPC patiensObjective Utilizing the feature of DW MRI able to noninvasive detect motion ofwater molecular in tissues, to measure the ADC value of salivary glands before andafter radiotherapy continuously. To study the relevance between the ADC valuechanges of salivary glands and degree of xerostomia in nasopharyngeal carcinoma(NPC) patients after intensity-modulated radiation therapy(IMRT). To analysis theeffect of different irradiation dose on salivary glands function, through observing thechanges of ADC value in salivary glands before and after IMRT. To evaluate theclinical application value of DW MRI for detecting the effect on salivary glandsfunction induced by radiotherapy.Materials and methods 23 NPC patients confirmed by pathology were enrolled.According to the NPC clinical stage,â… andâ…¡p atients were treated byIMRT alone,â…¢andâ…£p atients were treated byIMRT combined with concurrent chemotherapy. Allpatients underwent salivary glands examination by DW MRI before radiotherapy , atthe end of radiotherapy, 6 months and 12months after radiotherapy, at the same timethe ADC value of salivary glands were calculated. According to the RTOGï¼EORTCsalivary gland injury grading standard and referring the subjective index, the degreeof xerostomia was assessed.Resultsâ‘ After all patients finished IMRT, the mean irradiation dose of left and rightparotid were 28.977±10.923Gy and 29.034±11.416Gy respectively, the mean doseof bilateral parotid was 28.919±10.704Gy.â‘¡when the left and right parotid andsubmandibular glands comparied itself , a similar change tendency of ADC was foundin all patients before IMRT.â‘¢A similar change tendency of ADC in parotid andsubmandibular glands was found in different age and gender patients before IMRT.â‘£Before IMRT, the mean ADC value at rest was significantly lower in the parotid(1.033±0.046×10-3mm2/s) than in the submandibular glands(1.253±0.053×10-3mm2/s)( t=15.056,P<0.001). During the period of acid stimulation, the ADC valueof the salivary glands first showed a decrease, then followed by a steady increase. The ADC value of the parotid decreased to a minimum of 0.9046±0.041×10- 3mm2/s,reached after a mean of 4.6min(4.287min-5.017min), then followed by a increase to apeak of 1.208±0.043×10- 3mm2/s, reached after a mean of12.8min(12.25min-13.36min). The minimum and maximum ADC value weresignificantly different from the value at rest. The ADC value of the submandibularglands decreased to a minimum of 1.170±0.054×10- 3mm2/s, reached after a mean of4.0min(3.729min-4.271min), then followed by a increase to a peak of 1.322±0.056×10- 3mm2/s, reached after a mean of 12.21min(11.61min-12.81min). The minimumand maximum ADC value were significantly different from the value at rest.⑤At theend of IMRT, the ADC value of parotid (1.476±0.174×10-3mm2/s) andsubmandibular glands (1.723±0.226×10- 3mm2/s) were significantly higher thanbefore IMRT(P<0.001). At the end of IMRT, during the period of acid stimulationthe changes of ADC value in parotid and submandibular glands were not statisticsignificant(P>0.05).â‘¥At the end of IMRT, the change tendency of ADC in parotidand submandibular glands value was different in patients with different degree ofxerostomia(F=11.522,P<0.001).⑦At the end of IMRT, a signifinant difference fordegree of xerostomia could be found in patients within different irradiation dosegroups(Z=-3.622,P<0.001). Clinical stage, treatment mode and age had no significanteffect on degree of xerostomia for patients at the end of IMRT(P>0.05).⑧The ADCvalues of parotid in different irradiation dose group patients(group1 Dmean<26Gy,group2 Dmean≥26Gy)at rest were significantly higher at various time points afterIMRT than before IMRT(P<0.05). The ADC values of parotid in two grouppatients(group1 Dmean<26Gy,group2 Dmean≥26Gy)at rest were not significantlydifferent between 6 months after and at the end of IMRT(P>0.05). The ADC values ofparotid in two group patients at rest were significantly lower in the 12 months afterIMRT than at the end of IMRT(P<0.05). No significant difference was found in ADCvalues of parotid in two group patients before IMRT(t=0.229,P=0.819). The ADCvalue of parotid was significantly higher in patients with Dmean≥26Gy than patientswith Dmean<26Gy at the various follow-up time after IMRT(P<0.05).⑨The ADCvalues of submandibular glands at rest were significantly higher at the variousfollow-up time after IMRT than before IMRT(P<0.05).â‘©During the period of acidstimulation , A significant change of ADC in parotid was found in patients withDmean<26Gy(P<0.05) and no significant change of ADC in parotid was found inpatients with Dmean≥26Gy at the various follow-up time after IMRT(P>0.05). At the various follow-up time after IMRT, the average ADC values of parotid weresignificantly higher in patients with Dmean≥26Gy than patients with Dmean<26Gy inthe same time points of acid stimulation(P<0.05).⑾During the period of acidstimulation no significant change of ADC in submandibular glands was found afterIMRT(F=1.12,P=0.348).â‘¿A significant difference of xerostomia degree in patientswas found at the various follow-up time after IMRT(χ2=19.59, P<0.001).Conclusionsâ‘ During the period of stimulation before IMRT , the change trend ofthe ADC value in parotid and submandibular glands first showed a decrease, thenfollowed by a steady increase.â‘¡The ADC values of parotid were significantlyelevated after IMRT, although the irradiation dose less than 26Gy. The ADC values ofparotid decrease gradually with the extension of recovery time. The changes ofsalivary function can be well reflected by ADC values.â‘¢There is good correlationbetween DW-MRI and subjective rating of xerostomia for evaluating the effect ofradiotherapy on salivary.â‘£DW-MRI as a noninvasive tool can be used to evaluatethe functional changes in salivary glands during the period of gustatory stimulation.There is a good clinical application value of DW-MRI for evaluatingradiation-induced salivary glands functional changes and observing salivary functionrecovery during the follow-up period after IMRT. PARTâ…¡Clinical study of the effect of IMRT on normal oculartissues of nasopharyngeal carcinoma patientsObjective Through observing the various visual organ function changes ofnasopharyngeal carcinoma (NPC) patients after intensity-modulated radiation therapy(IMRT), to discuss the effect of IMRT on normal ocular tissues of nasopharyngealcarcinoma patients, to provide the theoretical basis for the clinician to take timely andrelevant treatment measures to minimize serious ocular complicetions induced byradiotherapy.Materials and methods 19 NPC patients confirmed by pathology were enrolled (38eyes). According to the NPC clinical stage,â… andâ…¡p atients were treated byIMRTalone,â…¢andâ…£p atients were treated bycombined with concurrent chemotherapy. Allpatients underwent visual acuity, slit lamp, dry eye, fundus, OCT and visualelectrophysiological examination before radiotherapy , at the end of radiotherapy ,6months and 12months after radiotherapy.Resultsâ‘ All patients finished IMRT, the mean dose of eye and optic nerve were10.840±5.866Gy and 23.903±11.079Gy respectively.â‘¡No statistically differencewas found in uncorrected and corrected visual acuity at the various examination timepoints before and after radiotherapy (P>0.05).â‘¢During the radiotherapy course andafter radiotherapy, patients showed different degree of conjunctival hyperemia and dryeye symptoms. Schirmerâ… test(SIT) shows that tear secretion was significantlyreduced at the end of radiotherapy than before radiotherapy under the condition ofunusing surface anesthetics ( F=3.994, P<0.05). 6 months after radiotherapy, tearsecretion was restored to the level of before radiotherapy. Under the condition ofunusing surface anesthetics, tear secretion was significantly reduced at the variousexamination time points after radiotherapy than before radiotherapy (P<0.05).Compared with the end of radiotherapy, tear secretion increased slightly at 6 monthsand 12 months after radiotherapy, the changes was not statistically significant(P>0.05).â‘£Tear break-up time (TBUT) TBUT was significantly shorter at thevarious examination time points after radiotherapy than before radiotherapy (P<0.05).Compared with the end of radiotherapy, TBUT significantly increased at 6 monthsand 12 months after radiotherapy, the changes was statistically significant (P<0.05).⑤ The average latency of VEP P100was significantly prolonged at 6 months after IMRTcompared with the time points of before IMRT, the end of IMRT and 12 months afterIMRT (P<0.05). The rest time points comparied each other, the changes of averagelatency and amplitude of VEP P100was not statistically significant (P>0.05).â‘¥Nostatistically difference was found in average latency and amplitude of ERG b wave atthe various examination time points before and after radiotherapy (P>0.05). At thevarious time points after IMRT , the average amplitude of Op2 wave was significantlylower than before IMRT (P<0.05). The average amplitude of Op2 wave wassignificantly higher in 12 months after radiotherapy than the end of radiotherapy(P<0.05). The rest time points comparied each other, the changes of averageamplitude of Op2 wave was not statistically significant (P>0.05).⑦The thicknessof macular central foveal was significantly higher at the end of radiotherapy thanbefore radiotherapy (P<0.05). The thickness of macular central foveal wassignificantly reduced in 6 months and 12 months after radiotherapy. Compared withthe end of radiotherapy, the difference was statistically significant (P<0.05). The resttime points comparied each other, the changes of average thickness of macular centralfoveal was not statistically significant (P>0.05).Conclusionâ‘ IMRT can ensure high radiation dose for the primary lesion ofnasopharyngeal carcinoma, at the same time it can significantly lighten the effect onvisual function.â‘¡There is different degree of tear secretion dysfunction in patientsafter IMRT. The basic tear secretion function impairment is more serious thanstimulated tear secretion function.â‘¢In spite of no significant morphological changesin retina and optic nerve can be found, the disorder of retinal blood circulation isexisted for a long time after IMRT.â‘£There is a good clinical application value ofERG and VEP for evaluating the effect of radiotherapy on retina and optic nerve,especially Op2 wave can reflect the effect of radiotherapy on retinal blood circulationsensitively.
|
PDF Full Text Request