Radioactivity in the service of man
By Anish Bhattacharya
RADIATION in different forms has long been used in medical diagnosis and treatment. Conventional X-rays and CT scans expose patients to relatively high radiation levels to obtain anatomical images of organs and organ systems.
Divali: happy & safe
Cancer: frankness pays
Drug-resistant HIV strain
Radioactivity in the
service of man
RADIATION in different forms has long been used in medical diagnosis and treatment. Conventional X-rays and CT scans expose patients to relatively high radiation levels to obtain anatomical (structural) images of organs and organ systems.
However, the disease process usually starts with a functional disturbance or damage to a body organ before any noteworthy structural damage is detected. Nuclear medicine utilises various chemicals, hormones, and even laboratory-synthesised precursor molecules labelled with miniscule doses of radioactive isotopes, to detect early pathological changes in organ function, and in some cases, to treat diseased conditions as well.
Diagnostic medical radioisotopes include gamma ray emitters like Technetium-99m, Thallium-201, Iodine-123 and Indium-III (all beta emitters). Other isotopes like Iodine-131, Phosphorus-32 and Strontium-89 are used for treatment.
Using sophisticated computer-assisted gamma cameras, high resolution functional images can be obtained of the organ system under investigation. For example, the passage of isotope-labelled blood through the heart can be imaged and quantitated to measure the efficiency of the cardiac output, the movement of the heart walls and to evaluate congenital defects in the heart causing abnormal shunting of oxygen-poor blood into the general circulation.
Thallium-201 chloride, injected intravenously during physical off exercise, concentrates selectively in the viable heart muscle with a good blood flow, but not in ischaemic or scarred tissue. This difference is exploited to obtain, computer-generated planar and cross sectional (SPECT) images of every part of the heart, to evaluate the amount of the healthy as well as damaged heart muscle, the necessity and utility of surgical intervention, and post-surgery quantification of the repair achieved. All this is possible without any invasive catheterisation on an outpatient basis.
The same isotope, Thallium-201, is also used to identify malignant tumours in the brain, the thyroid gland, the breast and the lungs and to differentiate post-surgical scarring and dead tissue from active cancerous growth.
Thyroid function has been evaluated using Iodine-131 uptake for 40 years now. Using Tc-99m, high quality images can be obtained of functioning thyroid tissue, with simultaneous calculation of the uptake function. Iodine-131, being a beta-emitter, is used for speedy control of thyrotoxicosis as well as destruction of cancerous thyroid tissue, even after the cancer has spread to the lungs or bones. Therapeutic nuclear medicine has thus helped in providing remission or cure in the majority of thyroid cancer patients.
The spread of various other cancers to the bones, especially breast, prostate and lung cancer, is routinely evaluated by nuclear imaging using Tc-99m, Methylene Diphosphonate or MDP. This technique can detect bone involvement upto three months before conventional X-rays, with the entire skeleton imaged in less than 30 minutes.
The bone scan is also used in identifying sport-related injuries, hairline crack fractures, avascular necrosis and infection of bones, and joint disorders much earlier than X-rays.
Gallium-67 and Thallium-201 have also been shown to detect spread of cancer to other organs, apart from the skeleton. In terminally ill patients, with bony spread of cancer causing unbearable pain, a single injection of Phosphorus-32 or Strontium-89 has been proved to provide significant relief for upto three months, thus improving the quality of life left to these patients.
Functional imaging of the genito-urinary system is one of the most cost-effective investigations offered by nuclear imaging. At less than 1/10th of the radiation dose of a routine chest X-Ray, individual kidney function and drainage can be calculated even in a new-born baby with no risk of any allergic reactions to the injected radiotracer (Tc-99m DTPA). Since kidney function as low as 1% of the normal can be detected, congenitally ectopic kidneys can also be located, and their function assessed.
Kidney-scarring due to infection is usually identifiable much earlier with the use of DMSA radioisotope imaging than with ultrasound, so the possibility of management, before permanent damage has occurred, is enhanced. The reflux of urine from the bladder into the kidney by DRCG can also be demonstrated without having to catheterise the patient, thus reducing chances of infection.
For kidney transplant patients, isotope renography can provide the earliest information about impending rejection of the grafted kidney. Other emergency situations where nuclear imaging is of vital importance includes detection and location of acutely bleeding sites in the intestines, pulmonary thromboembolism (sudden block in the blood circulation of the lungs), and myocardial infarction.
All these investigations do not come cheap. Gamma cameras, manufactured by less than a dozen reputed multinationals, cost a minimum of one crore rupees. While some radioisotopes are provided by the BARC, Mumbai, radiopharmaceuticals used for the studies can cost from Rs 1000 to Rs 15,000 per patient, when imported kits are used.
However, considering the vital information obtained with just an intravenous injection and without a very high radiation exposure to the patient, it is not surprising that an increasing number of physicians and surgeons are relying on nuclear imaging and treatment methods to augment other conventional techniques.
DIVALI celebrations include festive indulgence in lights, fireworks and often loud music. Unfortunately, indiscriminate and careless play with fire in lights and crackers causes major body injuries and even blindness. During celebrations involving fire, it is important to be conscious of their potential to cause injury. If you read on, you will find some useful tips to avoid injuries during Divali celebrations.
Major dos and donts
1. Procurement quality: Buy tested and authorised fireworks material and lights. It is important because the material made from unauthorised sources may have more dangerous explosive quantity and quality and other substances covering it. The fireworks may not perform as desired and explode in an uncontrolled manner, rendering the individuals nearby prone to injury.
2. Safe storage: Once procured, keep the fireworks and lights at a safe place away from children, heat and inflammable items.
3. Elders and childrens safety: Elderly persons and children are particularly prone to fireworks injuries because of slow protective reflexes or overindulgence and, therefore, must be accompanied by an active adult. Preferably, children and the elderly or the infirm should watch the fireworks display from a safe distance of about 10 metres.
4. Play and display in the open space only: It is always safe to enjoy fireworks in the open space in groups. Imagine the safety and community enjoyment when fireworks are displayed in the air in an open field such as a park with the neighbourhood sitting around at a safe distance. It is less costly too. Should the unfortunate injury happen, there is greater likelihood of immediate help being available. Many countries permit fireworks only in this manner.
5. Play one firework at a time: It is unsafe to let several fireworks to be ignited at the same time.
6. Wear cotton bodytight clothes: Inflammable and loose clothing, including sarees, kurtas and frocks, are more vulnerable and should be avoided while playing or lighting fireworks.
7. Play fireworks and lights the safe way only: In particular keep fireworks away from the body and do not ever bend over them. One of the most dangerous is the Anar type of cracker because it lights upwards and often has to be ignited while bending over it.
8. Keep safety aid available: The minimum is to keep some water and clean cotton handy in case of a fire or injury.
9. Do not hold lighted fireworks or throw them on the street without extinguishing them to avoid serious injuries to others.
10. Keep the sick in mind: Keep in mind that your play with fireworks and the sound may be affecting the sick in the neighbourhood or at a time when they need rest.
Causes of injury
Injuries from fireworks are a result of heat, particularly flying debris, unburnt chemicals, smoke and air-pressure shock waves. The injuries may remain trivial or may become devastating, depending upon the impact of the explosion. As the eyes, hands and other upper parts of the body are the closest to the fireworks being played, these are affected most. The eyes could have thermal burns affecting the lids or the cornea, tears and ruptures of the eye-ball involving the cornea or the sclera.
Internal structures including the lens and the retina may be damaged because of shock waves. Foreign bodies may get impacted in different layers of the eye and cause corneal ulcers. Chemicals in explosives tend to result in a relatively deep and severe damage to the cornea. Other sequelae like glaucoma and inflammation complicate the further course of eye damage.
What should be done?
In the eventuality of an injury, do not panic and help the victim get away from the site.
Help provide copious washing of the eye with clean water.
Do enough water lavage to quickly cool the injured area and wash away superficial foreign bodies.
Dot not rub the eye.
Do not force open the eye.
Do not, preferably, put any medication in the eye. If the eye can be easily opened, smear a fresh antibiotic drop or an ointment near the lid margin only. Keep the eye closed.
The area of injury needs to be evaluated by an ophthalmologist and you should arrange to visit an eye emergency clinic as soon as possible for advice based on the extent of injury.
CANCER is a common illness and the lay public still tends to view a diagnosis of cancer as an imminent death sentence. It takes many different forms and it is important to realise that it is not inevitably fatal.
For patients, it is important to accept that bad news cannot be turned into good news. The task for the doctor is to ease the patients from their perception of the situation into the reality of that situation.
Surgeons are placed in a critical position. Adequate preparation and time are essential for breaking the news in order to avoid psychological scarring. Telling the disease to the patients enables better psychological adjustment and facilitates an open discussion between them, their relations and the doctors. Even though many relatives request the doctor not to disclose the disease to the patient, in practice it is not practical because this may lead to the loss of confidence in the doctor at a later stage. The strain on relatives of maintaining a secret can be immense. One can explain the difficulties that can be caused by patients not knowing their diagnosis.
Many patients cry after hearing that they have cancer. The doctor should avoid looking embarrassed and should let the patient know that this is understandable and normal behaviour. Anger is a fairly common response.
The doctor can help discharge this by listening and letting the patient give vent to his feelings.
The emotional support of such patients is critical to their overall well-being.
Patients desire to know the chance for cure, the likelihood of survival from their disease, and how long they are likely to survive. Quoting inflated success rates for treatment should be avoided as it can lead to anger and bitterness if they fail. Patients ask How much time have I got? It is best to avoid a specific prediction. It is better to acknowledge the uncertainty of the situation. One must emphasise the difference between treatment and cure. If cure is not possible, it should be conveyed to the patient and the relatives.
It is extremely vital to state the aim of any treatment surgery, radiotherapy or anticancer drugs. The primary aim of a therapy is to render the patient free of disease and to prevent its subsequent recurrence without harming him. When this is not possible, the goal is to control tumour growth or palliate the symptoms. The difficulty lies in reliably anticipating a tumours progress.
Provide enough information about the surgical procedures and the risks of the operation. The long-term medical and psychological sequel of a large cancer operation must be adequately explained to the patients and reinforced after surgery in follow-up visits.
Patients should be fully informed of the potential benefits and risks of the procedures and of any suitable alternative management.
One of the major concerns in allowing patients to be involved in decisions about the treatment is that they will have a more severe reaction to the discovery of recurrent disease because of the feeling that they made the wrong decision in the first phase and that the recurrence is their fault. This is especially in persons with breast cancer when they originally opt for a breast conservation procedure. The surgeon needs to reassure the patients that they should not have any feeling of guilt on this score.
Reassurance about continuing support should be offered. It is extremely important to highlight positive help and the opportunity of practical advice following a particular modality. Survival following a cancer has been shown to be related to the patients psychological response to the disease not only in early cases but also in those with advanced disease as well.
The experience of cancer is an extremely stressful event. A surgeon plays a critical role in the cure of these patients. Many issues emerge at diagnosis and continue through periods of remission, relapse, palliative care, terminal illness and long-term survival.
A frank discussion about treatment details is helpful. Reassurance about continuing support should be offered. Comprehensive care seems essential to assuring that these patients are given every opportunity for a physically and psychologically healthy future.
(To be concluded)
Drug-resistant HIV strain
New tests are helping identify treatment-resistant strains of the AIDS virus, allowing doctors to customise the drug cocktails given to their patients, reports AP.
The AIDS virus rapidly mutates, or changes genetically, to resist the drugs thrown at it. As a result, some patients get no prolonged relief from their first try on the powerful combinations of drugs now available against HIV.
To help doctors find an effective combination, scientists are developing resistance tests and marketing them.
But the tests do not have a long enough track record to be used routinely, a panel assembled by the International AIDS Society USA has said in the Journal of the American Medical Association.
Until more study, the tests are appropriate only in certain situations, said the team, led by Dr Martin S. Hirsch, Director of Clinical AIDS Research at Massachusetts General Hospital.
There are two types of tests one that looks for genetic mutations that have known drug resistance, and another that directly measures whether a drug will kill the AIDS virus taken from an individual patient.
HIV treatment usually involves two older drugs and one of the newer class of medicines called protease inhibitors. Such cocktails have revolutionised therapy, reducing the virus to nearly undetectable levels in the body.
Resistance to such cocktails is still relatively rare, and routinely screening HIV-positive patients before starting them on treatment is not justified, the panel said.
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