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      “A CHUNK OF THORIUM IS NO MORE HARMFUL THAN ABAR OF SOAP”  Richard Martin, famousjournalist with extensive experience in Thorium

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    According to IARC (International Agency for Research on Cancer) NaturalThorium CANNOT CAUSE CANCER WHEN SWALLOWED OR INHALED.

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    ATSDR (Agency for Toxic Substances and Disease Registry) of the USAgovernment stated “Thorium was once thought to cause cancer in mine and millworkers, but it was later concluded that thorium likely had no significantimpact on their cancer risk.  Cancers inthese workers were likely due to their cigarette smoking and inhaling silicadust. The International Agency for Research on Cancer (IARC) has NOT FOUNDSUFFICIENT EVIDENCE TO CLASSIFY THORIUM IN MINES AND MILLS AS CARCINOGENIC.”

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    Natural Uranium which has an activity of 25,400 Bq/g is notregarded as a carcinogen by IARC and yet because of Thorotrast, Thorium 232with an activity of only 4080 Bq/g is classified as a carcinogen IF GIVENINTRAVENOUSLY AS A COLLOIDAL SOLUTION OF THORIUN DIOXIDE.

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    The main problem is that practically all the papers on Thorotrastdo not take into account the massive dose of X-rays radiation patientsundergoing Fluoroscopy were subjected to with those archaic X-raymachines...often more than 1,000 mSv.

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    If doctors were to use such high doses nowadays, they would becharged for first degree murder!

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    Alpha particles has been classified as a carcinogen, but thealpha particles from natural thorium has a very low energy level of only 4.4MeV and can traverse only 2 to 5 human cell diameters.

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    The most abundant gamma rays from Thorium in secular equilibriumis only 12.3 keV (compare this with Potassium which is 1,460 keV).

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    Alpha particles are regarded as 20× more harmful than gammarays..but  this is not valid with thelining  cells of the gut and respiratorytract...because the life span of these cells is only 4 to 10 days. Cancers takemonths or years to develop.

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    The cells of the gut and respiratory tract die and sloughed offlong before they can turn cancerous!

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    That may be why IARC has not been able to find any evidence thatboth natural Thorium and natural Uranium can cause cancers.

     

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    Thorium-232 is considered to be a carcinogenonly IF ADMINISTERED INTRAVENOUSLY AS A COLLOIDAL DISPERSION OF THORIUM-232DIOXIDE." (IARC).

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    However, this may not be the complete picture.

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    Below are the unknown parameters whencalculating the actual biological dose of radiation caused by the Thorium-232in patients given "Thorotrast Fluoroscopy".

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    1.   The interval of time when the Thorium-232 waschemically isolated and used to manufacture the "Thorotrast". This isvery important as the alpha, gamma and beta activity of varies with time and islowest 3 years or so after chemical separation and it is only after 60 yearswhen the final equilibrium is achieved.

     

    2.   The interval of time before the Thorotrastwas actually injected into the patient.

    3. The amount of Thorotrast was known to bebetween 10 ml to 75 ml (3 vials), but in those patients who ultimately developcancer 20-30 yrs later, the actual amount is not known.

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    4. How many fluoroscopic examinations wereeach of those patients with cancer were subjected to in their lifetimeespecially those who developed cancers.

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    Of all the above factors, the time factorfrom Thorium-232 chemical isolation to Thorotrast manufacture and to actualparenteral injection of the Thorotrast is the one which is almost impossible todetermine though this is very important in the calculation in the biologicalradiation dose from the Thorium-232.

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    The mean latency period for all tumour typeswas between 25 and 30 years (Frank 1980).

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    Most of the papers I have read, the dose ofX-ray radiation is unknown and the absorbed dose from the Thorium-232 is alsonot known.

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    Only in one of the studies the mean value ofabsorbed dose to the liver was given and calculated to be 876 rads forhepatocellular carcinoma and 1053 rads for cholangiocarcinoma (Mori et al.1983b).

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    Unfortunately I have lost the originalarticle of this paper when I moved house, but I cannot remember how thiscalculation was made...but if we do not know the time interval between thechemical separation of the Thorium-232  and it's final administrationto the patient, it is next to impossible to calculate the actual dose.

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    Because of the variable nature of theradiation activity of "pure" freshly chemically separated Thorium-232(Thorium-228 cannot be chemically separated), and even if we know the biologicalhalf life the the Thorium-232, it is virtually impossible to estimate the totaldose given to these patients.

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    When thorium is separated from other isotopesin the decay series, the thorium fraction has only a slight alpha activity.

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    There is no beta radiation and only a slightamount of gamma radiation (from the 0.09-MeV gamma rays which emanate fromTh-228 decay).

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    However, the activity from the Th-228 side ofthe chain is quickly re-established.

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    A first equilibrium state is reached in about36 days (10 half-lives of Ra-224).

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    Activity then declines, as Th-228 decaysfaster than it is replenished by decaying Ac-228.

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    About 3 years after separation, the activityis lower than at any other time except immediately after separation.

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    From this point, activity increases until thesecond equilibrium state is reached in about 60 years.

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    There is an initial buildup, decline, andsecond buildup of alpha and beta activity.\.

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    SO IS THORIUM-232 THE REAL CAUSE OFCANCER IN PATIENTS INJECTED WITH THOROTRAST?

    Dosage in "Thorotrast" Fluoroscopy = ~1,000 mSv (100 Roentgens)

    Risk in developing Cancer = 1 in 20,000 per mSv

    Therefore risk with 1 Thorotrast Fluoroscopy = 1 in 20

    Therefore in about 4 million patients, number of patients developing Cancers =200,000 from X-ray induced Cancers!

    AND SOME OF THESE PATIENTS MAY HAVE MORE THAN 1 FLUOROSCOPIC EXAMINATION ANDNUMEROUS OTHER X-RAYS IN THEIR LIFETIME.

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    SO IS IT FAIR TO CONCLUDE THATTHORIUM-232 IS A CARCINOGEN, based mainly on the results of studies onThorotrast study alone?
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    (In an attempt to prevent someinjuries, A LIMIT OF 100 ROENTGENS (approximately 1,000 mSv) per fluoroscopicexamination was set in New York City hospitals (Braestrup 1969). Prior to this,the dosage from the "Thorotrast" Fluoroscopy may be much higher !

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    The InternationalAgency for Research on Cancer ( IARC ) categorized Thorium-232 and its decay products asa group 1 carcinogen when administered intravenously as a colloidal dispersionof thorium-232 dioxide.

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    This conclusion was made mainly onthe study of certain types of cancers which were found to be increased inpatients given Thorotrast for radiological investigations.

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    SO IS IT FAIR TO CONCLUDE THATTHORIUM-232 IS A CARCINOGEN, based mainly on the results of studies onThorotrast study alone?

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    Thorotrast was given as a contrast media viathe vein or artery and the dose of Thorium used was huge, though this dependson the type of radiological procedure done. 
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    It had been estimated that as many as 4 million people were given this contrastin the 1930 to late 1950s.
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    It has been claimed that there was an increase in the incidence of cancersespecially of the liver.
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    However, we need to consider a number of factors before we can be sure thatthis is the real culprit.
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    1) The radiation dose from those old X-ray machines in the 1930 to 1950s arehundreds of times that of the present machines.
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    For instance an 1896 X-ray machine was tested and found to have exposed thebody to 1,500 times more radiation than modern technology does, largely becauseeach image took 90 minutes to develop, dramatically increasing the patient'scumulative exposure to the rays. By 1930 to 1950s, the radiation dose haveimproved a lot but still much higher than the present X-ray machines. 
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    Modern day X-rays require only about 21 milliseconds, and technicians placelead coverings over the body to protect vital organs from even this slightexposure.
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    Even in the 50s and 60s, the dose of X-rays from Tuberculosis screening isabout 100 times higher than that of today's Chest X-Ray.
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    The fluoroscope leaves the X-ray beam "on" while the physician doeshis examination and as such, the fluoroscope has the potential to deliver veryhigh X-ray doses.
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    In the 1920s, fluoroscopy became very popular procedure not only amongradiologists, but also among many kinds of physicians.
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    Radiological methods of diagnosis became so important that no investigation ofa patient is considered complete without the X-rays, which generally includefluoroscopy. These studies are often carried out by a general practitioner orsurgeon in his office. 
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    In 1942, Dr. Franz Buschke and Herbert M. Parker wrote (Buschke 1942): 
    "Recently we became aware of the fact that apparently a number ofpediatricians include fluoroscopy in the monthly routine examinations ofinfants in their care during the first and second years of life." Thispediatric practice is confirmed in Pifer 1963 and in Blatz 1970. 
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    After studying the radiation output of seven fluoroscopes in the offices of"reputable pediatricians selected at random," Buschke and Parkerestimated (Buschke 1942, p.527): "If the average rapid fluoroscopy by anexperienced and well-adapted examiner takes twenty seconds, about 8.3 roentgens[entrance dose] will be delivered at this rate or 100 roentgens during thefirst year of life." The roentgen is a dose-unit which is approximatelyequivalent to a rad (actually it is less as the ICRU defined the roentgen to be2.58e -4 C/Kg in 1971)
    Fluoroscopy was popular also in hospitals. 
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    (Braestrup 1942, p.213): 
    "During the past years, we have measured the roentgen output of largenumbers of fluoroscopes, using the settings at which they are normally operated... and have found a very wide variation ... Attention is called particularlyto test B-116, where the R [roentgen] per minute at the panel was 127, that is,an erythema dose would be reached in about three minutes. Such a unit could beclassified as a lethal diagnostic weapon and yet there are many of these stillin use."
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    Of the various types of radiologic equipment, the mobile unit probably has beenresponsible for more radiation damage than any other piece of apparatus. Theseaccidents have in most cases occurred while the mobile unit was used forfluoroscopy by surgeons, who apparently did not realize the high outputobtained at short distances." 
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    In an attempt to prevent some injuries, A LIMIT OF 100 ROENTGENS (approximately1,000 mSv) per fluoroscopic examination was set in New York City hospitals(Braestrup 1969). 
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    The patients who received the Thorotrast were subjected to a huge dose ofX-rays from these antique X-ray machines. 
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    This huge dose of X-rays may be the cause of most of the cancers, we just donot know as most of the studies are unable to assess the X-ray's dose. Allthese studies are done 20 to 30 years later.
    So we cannot use other patients who have X-rays done in the 1930s to 1950s as acontrol group since most X-rays which do not need a contrast media consist ofonly 1 or 2 X-ray pictures.
    A few of the studies do have controls but these controls were cases from lateryears especially after 1947 when the advancement in radiological techniques andhence dosage reduction is greatest.
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    It is generally accepted that the risk of radiation induced cancer is 1 in20,000 per mSv.
    As such, a dose of about 1,000 mSv would mean a risk of 1 in 20. For 4 millionpatients injected with Thorotrast, THIS RADIATION WOULD GIVE RISE TO AN EXCESSOF 200,000 CASES OF RADIATION INDUCED CANCERS IN THE 4 MILLION CASES OF"THOROTRAST" PATIENTS!
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    In 1953, Dade W. Moeller (then of the Public Health Service; later, presidentof the Health Physics Society) published an estimate that the average entrancedose per fluoroscopic examination was about 65 roentgens (about 650 mSv) atmid-century (Moeller 1953, pp.58-59).
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    The use of Thorotrast was discontinued by 1953.
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    2) The contrast studies are usually done for patients who are rather ill andmay have multiple other disorders.
    The cancers usually appear (as most cancers do) about 20 to 30 years later whenthe patients reach the "cancer" age. Because of this long lapse ofcause and effect, all the studies are retrospective in nature.
    And as you know, all retrospective studies are full of problems andinaccuracies.
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    3) A lot of these patients, have other disorders which may also lead to cancerlike alcoholic cirrhosis, hepatitis B and hepatitis C. In fact the first caseof liver cancer I saw in Manchester was an old alcoholic with severe livercirrhosis. But he also had Thorotrast contrast study more than 20 yearsearlier. Because of this history, the surgeon had to report him as a Thorotrastinduced cancer.
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    4) With about 4 million by now old people, we are bound to come across a lot ofcancer cases. Since the life time risk of cancer in the advanced countries is 1in 5, there should be about 800,000 cases of cancer due to other causes. 
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    So how many if any of these (taking into account all the above problems) arereally caused by the radiation from the massive dose of intravenousThorium-232... nobody can be really sure. If anybody says he can tell, theneither he is lying or he does not know what he is saying.
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    https://hotcopper.com.au/data/attachments/1405/1405890-ef491eca2940d53ff839bfa605ace0a0.jpg

 
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