The use of radium in medicine and industry is discontinued in many countries. The development of radium in medicine was one of the most significant steps in the fight against cancer. Radium needles for interstitial implantation and radium tubes for intra-cavitory use dominated the scene. Clinical dosimetry based on radium became the corner stone in brachytherapy.
When radium was replaced by safer substitutes appropriate changes in distribution of sources were arrived at on the basis of doses equivalent to those delivered by radium. I have covered the history of radium in India in a PTI Feature which was published on September 3, 2010
VOL NO XXVII (37) September 3, 2010
The Use of Radium: Down the Memory Lane
Dr K S Parthasarathy
Madame Curie and Pierre Curie separated radium from uranium ore on December 26, 1898. She processed several hundred kilogramme of ore to get 100 mg of radium in four years.
Within a few years, radium was used very widely in treating benign and malignant tumours. Over a century of use of radium in the healing arts is one of the finest chapters of human history.
Conflicting claims have come from France, Germany and the USA as to who first implemented radium therapy. In the June 2007 issue of Current Oncology, Dr R F Mould wrote that in 1903, Hermann Strebel of Munich proposed the use of radium enclosed in the drilled-tip of a small aluminium rod, directly into the centre of the tumour, with the help of a previously inserted trepan.
The earliest stock of radium in India arrived at the Radium Institute, Patna, in 1930. Over the years, sixty-five Indian hospitals had totally about 20 grams of radium contained in the form of a fine powder in hundreds of thin platinum-iridium tubes and needles.
In 1936, Dr. Ramaiah Naidu a former associate of Madame Curie set up the first radon plant at Tata Memorial Hospital, Mumbai. With 2 g of radium in the plant. he made thousands of radon seeds for treating cancer. Radon, the daughter product of radium decays into its daughter products; some of these emit gamma rays. The gamma radiation out put from the seed decays with a half life of radon (3.8 days). The seeds may be implanted into the tumour. From the primary stock of radium, radon can be “milked” and sealed into gold or glass seeds. In 1941, Naidu made 3600 seeds.
During World War II, he dried out the radium solution and removed it from Bombay city as war time bombing was considered to be an unacceptable risk to radium, a very costly element.
Since 1957, scientists from the Bhabha Atomic Research Centre (BARC) assisted hospitals to separate leaky sources. Radium, a bone seeker, is highly radiotoxic. It has a half life of 1610 years. The maximum permissible body burden of radium-226 is 0.1 microgramme.
The safety status of some radium departments in India was deplorable. Once, BARC scientists recovered five radium tubes from a crematorium; a hospital carelessly released the body of a patient without removing the sources.
In another incident, a physician asked an electrician to cut open an applicator to remove radium tubes stuck in it! He damaged a tube, leading to extensive contamination. BARC scientists decontaminated the site and transported a truckload of materials in sealed containers to Trombay for safe disposal.
Several sources became leaky due to uncontrolled heat sterilization and inadvertent rough handling. Many needles got bent when physicians applied them directly by piercing tissue.
Many hospitals lost sources; few had the equipment or the expertise to locate them.
In a poorly ventilated room, even a single leaky source could cause an unacceptably high concentration of radon and its decay products. BARC scientists recovered sources stuck in storage-safes. Once a member of the hospital staff who leak-tested radium carelessly received a dose of five times the annual dose limit. In some hospitals, Accounts personnel reportedly insisted on counting the sources manually as a part of the annual physical verification. They did not use any safe handling tools!
In 1980, a paper titled `Leaky radium: an appraisal of potential risks’ presented by me at the Third Annual Congress of the Association of Radiation Oncologists of India, brought out the callous disregard of some hospitals to a potentially hazardous situation.
Forty-two hospitals were chosen for a free survey using a mailed detector method. Only eighteen cooperated. We found leaky sources in eight of them.
In view of the potential hazards, BARC recommended replacement of radium with safer substitutes. Many newspapers prominently published the results of the survey. Indian Express wrote an editorial on it. The hazards of handling old radium tubes and needles attracted public attention for the first time. The Department of Atomic Energy imported tubes containing caesium-137, a safer substitute, at a cost of Rs 1.5 million to replace radium. A DAE committee chaired by Dr K A Dinshaw designed an applicator to load caesium-137
The Board of Radiation and Isotope Technology (BRIT) distributed the applicator in the form of a kit loaded with caesium-137. Later, BRIT fabricated caesium-137 sources indigenously.
On August 25, 1988, the Atomic Energy Regulatory Board (AERB) directed the withdrawal of radium from hospitals and its safe disposal in the interest of overall radiation safety. In a unique gesture, BARC collected and disposed of the sources safely. Unused radium remains in hospitals in many countries as there is no such agency to take it away.
As physicians and technicians handled applicators already loaded with radium, they used to receive radiation doses higher than any other medical users of radiation.
With safer substitutes such as caesium-137 and iridium-192, used after-loading devices, the patient receives accurate doses; the radiation doses to hospital personnel became less or negligible.
In 2003, AERB helped a family in Kolkata to dispose of their `inherited’ radium stock of about 70 mg. They realised that it was hazardous to keep radium. Handling radium accidents is risky and expensive. In one incident in USA, a hospital spent $ 250,000 to handle an incident. If any one has information on any radium stock, they must inform AERB about it.
For several decades, tens of millions of patients received successful radiotherapy with radium. Techniques developed in France, Sweden and United Kingdom provided invaluable clinical experience making radium therapy a most effective form of treatment for certain forms of cancer.
Currently, over 200 remote after-loading applicators and about 80 manual after-loading devices loaded with safer radioisotopes are in use in the country. Decision to replace radium gave an impetus to the programme, though it continues to remain very modest for a country of such a huge population.