Establishment of Methodology and Treating Efficiency to Treat Hyperthyroidism with Low Dose Iodine-131 Combined with PTU
|Course||Medical Imaging and Nuclear Medicine|
|Keywords||hyperthyroidism hypothyroidism 131I low dose PTU|
Nowadays,thyroid diseases are commonly seen and frequently-occurring on clinic,especially thyroid swelled filling in the air andhyper-function.Hyperthyroidism is a kind of special self-immunedisease with increasing of thyroid hormone.The mechanism of thisdisease is uncertain now,but there are several factors relating tohyperthyroidism.There is special self-antibody toward TSH receptorof thyroid cell,which is named the antibody of TSH receptor(TRAb).Both TSH and TRAb can combine with TSH receptor andthe biological effects come into through signal transferring way.Thebiological effects as follows:the proliferating of thyroid cell andincreasing of synthesizing and secretion of the thyroid hormone.Environmental factors may also take part in the happening ofhyperthyroidism,such as immune malfunction 、heredity、infection、sex hormone、lithium and spirit factors.There are several methods with which we can treathyperthyroidism, including anti-thyroid drug therapy 、131I therapy、thyroid sub-cutting operation 、 traditional medicine therapy 、embolism therapy and regional injection of immune inhibitor therapyand so on.The former three methods among them are often used onclinic,but all of them have their advantages and disadvantages.There have been more than 1,000,000 cases of hyperthyroidismtreated by 131I since Hertz reported the first case of hyperthyroidismwhich was treated by 131I in 1942.This treating method is taken moreand more seriously on clinic because of its postive efficiency、simpleoral intake way and capability of repeating therapy.It is believed that131I therapy is the best choice for hyperthyroidism by thyroid diseaseresearch experts ,who followed up research to therapy methods ofhyperthyroidism in America.Although the latest analysis shows thatit is in the highest ratio bewteen cost and benefit treating Graves’hyperthyoidism with 131I, there are some negtive aspects,such asearly-hypothyroidism or permanently-hypothyroidism.Foreign datashows that there is twenty percent of early-hypothyroidism(occurring in the first year after 131I therapy ), increasing two to threepercent per year in the following years,and there has been more thanfifty percent of hypothyroidism after ten year post-therapy.Meanwhile,the native data suggests that the incidence ofeartly-hypothyroidism is between zero to ten percent and theincidence of permanently-hypothyroidism is between 2.2% to59.8%.The incidence of hypothyoidism is high in both foreign andour native nations. It is always concerned and investigated byclinical doctors of Nuclear Medicine Department selecting anappropriate treating method which can not only curehyperthyroidism but also decrease the occurence of side effects.The dose of 131I adopted in foreign nations is from 195 to 800MBq(5.3-21.6mci) and the dose of 131I in our native nation is from5 to 15 mci.We treated 168 cases of hyperthyoidism by low dose 131Iand PTU,including 64 males and 104 females among them. Theywere from 25-year old to 61-year old.All patients were diagnosedthyroid swelled filling in the air and hyper-function,according totheir clinical symptom and thyroid function test(TT3、TT4、FT3、FT4 、sTSH and thyroid 131I intake test).Firstly, their thyroid glandswelled from soft to mediate . Secondly, their hyperthyroidismsituations were mediate . Thirdly,there was no other complicationsand all of the patients were fit for 131I therapy. All cases were given131I 111-148MBq(3-4mCi),taking it one time on an emptystomach.The oral intake dose of PTU was ascertained by thepatients’ serum levels of TT3、TT4、FT3、FT4 、sTSH and clinicalsymptom.We treated 219 cases of hyperthyroidism withconventional 131I method as controls at the same period.There were89 males and 130 females being in from 14-year old to 75-yearold.The personal dose of 131I were given according to the formulacombined with the quality of thyroid、the course of the disease、theeffective half time and the situation of other therapy.All of the caseswere followed up at the regular time,the shortest time of followingup was 13 months, and the longest was 18 months. The treatingefficency was decided as follows:1、Cured:the symptom and physicalsignals of hyperthyroidism disappear completely and the serumlevels of TT3、TT4、FT3、FT4 and sTSH decrease to normal.2、Improved:the symptom of hyperthyroidism ease and part of thephysical signals disappear and the serum levels of TT3、TT4、FT3、FT4 decrease but not to decrease to normal.3、No efficency: thesymptom and physical signals of hyperthyroidism have little changeor deteriorate and the serum levels of TT3、TT4、FT3、FT4 and sTSHhave no significient decreasing.4、Hypothyroidism:there are thesymptom and physical signals of hypothyroidism after 131I therapy,and the serum levels of thyroid hormone are lower than normal andthe serum level of sTSH is higher than normal.All cases were tested the serum levels of FT3、FT4 and sTSH byradioimmunoassay(RIA) after 1 month post-therapy 、 3 monthpost-therapy、4 month post-therapy 、6 month post-therapy and 1year post-therapy respectively.The results as follows:1、 Theserum levels of FT3、FT4 decreased greatly comparing 1month post-therapy with before therapy(P﹤0.05,t=1.91、1.23);The serum level of FT3 decreased greatly(P﹤0.05,t=0.84),but the serum level of FT4 decreased slowlycomparing 3 month post-therapy with 1 monthpost-therapy;The serum levels of FT3、FT4 decreasedslowly comparing 4 month post-therapy with 3 monthpost-therapy;The serum levels of FT3、FT4 became steadyin the 6 month post-therapy,Which may be related toPTU.Because PTU can not only inhibit thyroid hormonesynthesizing as conventional ATD,but also inhibit T4turning to T3.So FT3 decreased greatly in 3 monthpost-therapy.2、The rate of cases whose serum levels ofFT3、FT4 decreased greatly and decreased to normal wassignificantly higher comparing the low dose 131I and PTUgroup with conventional 131I group after 1 monthpost-therapy and 3 month post-therap(yP﹤0.01,x2=51.86、12.30),but the rate of cases whose serum levels of FT3、FT4 decreased greatly and decreased to normal levels wasnearly same between the two groups in 6 monthpost-therapy(P>0.01, x2=3.19),Which illustrats that lowdose 131I and PTU can make the serum levels of FT3、FT4decreased rapidly and control hyperthyoidism symptom in3 month post-therapy because of their pharmacologicaleffects.3、There was no significant difference between thetwo groups(P>0.01,x2=0.68、0.55、0.00089),comparingthe cured、the improved and the no efficient cases after oneyear’s therapy, but there was significant difference onincidence of hypothyroidism between the two groups(P﹤0.01,x2=11.97).There were two cases(1.2%) of early-hypothyroidism in low dose 131I and PTU group,but therewere 15 cases (6.8%) of early-hypothyroidism inconventional 131I group.The hyperthyroidism symptom wascontrolled by the pharmacological effects of 131I andPTU.It shows that the incidence of early-hypothyroidism isdecreased greatly and there has no effect on treatingeffectiency, although the dose of 131I is decreased.Early-hypothyroidism can turn to two directions:oneis temportorily-hypothyroidism that early-hypothyroidismcan return to normal thyroid function by self-regulation orlow dose thyroid hormone substituting therapy;the other ispermanently-hypothyroidism.Sumrizing several reports,there is 38.9% to 78.3% early-hypothyroidism turning topermanently-hypothyroidism. All above show that onprimise of no affection to the treating effects ofhyperthyroidism, the incidence of early-hypothyroidismdecreases greatly, meanwhile the incidence ofpermanently-hypothyoidism decreases accordingly,although the dose of 131I is decreased.This treating method has its adventages:the dose of131I is decreased;the longest time of PTU oral intake isdecreased to six months;the side effects such asdrug-induced rash 、 white blood cell decreasing 、 liverdamaging and so on are all decreased;the incidence ofhypothyroidism is decreased greatly comparing withconventional 131I method.Simply put,this treating method isworth popularzing on clinic .