Tag Archives: Radioactive decay

Psidium cattleianum

Botanical Name: Psidium cattleianum
Family: Myrtaceae
Subfamily: Myrtoideae
Genus: Psidium
Species: P. cattleyanum
Kingdom: Plantae
Order: Myrtales

Synonyms : Psidium cattleianum. Salisb. littorale (O. Berg) Fosb., Psidium littoraleRaddi

Common Names: Cattley guava, Strawberry guava or Cherry guava
The red-fruited variety, P. cattleyanum var. cattleyanum, is commonly known as red cattley guava, red strawberry guava and red cherry guava. The yellow-fruited variety, P. cattleyanum var. littorale is variously known as yellow cattley guava, yellow strawberry guava, yellow cherry guava, lemon guava and in Hawaii as waiaw?.

Habitat : Psidium cattleianum is native to Brazil where it is known as araçá (ara-SAH) and adjacent tropical South America, it is closely related to common guava . Now it is cultivated in tropical and semi-tropical areas worldwide for its fruit and as an ornamental. It has escaped cultivation and become a serious weed in various Indian and Pacific Ocean locations, and is considered the worst invasive plant species in Hawaii. The strawberry guava is similar in flavor and uses to guava (P. guajava), but is generally smaller (although considered to be more attractive). Other guava fruits that are commercially grown are the Costa Rican guava (P. friedrichsthalianum) and the Guinea guava (P. guineense).

Psidium cattleianum is a shrub or many-branched small tree, with smooth brown bark and slender branches, which may reach heights of up to 12 m (39 ft), although typically growing to 2 to 4 m (6 to 13 ft). Some varieties are moderately frost-tolerant, and may be hardier than P. guava.It is in leaf 12-Jan It is in flower in May. The flowers are hermaphrodite (have both male and female organs) The leaves are oval to elliptical, up to 4.5 cm (1.75 in) long, smooth and leathery to waxy, with prominent veins. The fragrant white flowers are tubular with 5 petals, and are larger than the leaves, to 6 cm (2.3 in) wide, and are either solitary or in clusters of 3 at the axils (where leaf meets stem). The fruits, which are produced when the plants are 3 to 6 years old, are round to somewhat oval, about the size of a walnut around 4 cm (1.5 in) long, with a thin skin that ripens to a color ranging from yellow (in var. lucidum) to dark red or purple, tipped by the remains of the calyx (somewhat like an apple or blueberry). The juicy flesh, which is white or yellow, has many soft seeds embedded in it……CLICK & SEE THE PICTURES


Requires a well-drained sandy loam with leafmold. Requires cool greenhouse treatment in Britain. Tolerates short-lived light frosts and cool summers so it might succeed outdoors in the mildest areas of the country. Dislikes much humidity. Sometimes cultivated for its edible fruit, there are some named varieties.

Seed – sow spring in a warm greenhouse. When large enough to handle, prick out the seedlings into individual pots and grow them on in the greenhouse for at least their first winter. If trying the plants outdoors, plant them out in the summer and give them some protection from winter cold for at least their first two winters. Cuttings of half-ripe wood, July/August in a frame.

Edible Uses :
Edible Parts:……Fruit – raw or cooked. The fruit can be used in jellies, jams, custards, drinks etc. Sweet and aromatic. The flavour is more pronounced than that of the yellow strawberry guava but lacks the muskiness of the common guava. The fruit has an agreeable acid-sweet flavour and is good when eaten raw, though it can also be used in preserves. The fruit is about 4cm in diameter.

Medicinal Uses : Not Known

Other Uses: …..Hedge; Hedge……..Grown as a hedge in warm temperate climates

Thyroid Scan

A thyroid scan uses a radioactive tracer and a special camera to measure how much tracer the thyroid gland absorbs from the blood. A thyroid scan is done to find problems with the thyroid gland. A thyroid scan may be done to check for thyroid nodules, or it may be done with a radioactive iodine uptake test (RAIU) to check how well the thyroid gland is working.

You may click to see the pictures

A thyroid scan can show the size, shape, and location of the thyroid gland. It can also find areas of the thyroid gland that are overactive or underactive. The camera takes pictures of the thyroid gland from three different angles. The radioactive tracer used in this test is either iodine or technetium.

A radioactive iodine uptake test measures the amount of radioactivity in your thyroid after you’ve been given a relatively small dose of radioactive iodine in pill form. Your thyroid gland absorbs iodine and uses it to make hormones. Therefore, the amount of radioactive iodine detected in your thyroid gland corresponds with the amount of hormone your thyroid is producing.

Another type of thyroid scan, a whole-body thyroid scan, may be done for people who have had thyroid cancer that has been treated. The whole-body scan can check to see if cancer has spread to other areas of the body.

Why It Is Done:-
A thyroid scan is done to:

*See whether thyroid nodules are present.
*Find the cause of an overactive thyroid gland (hyperthyroidism).
*See whether thyroid cancer has spread outside the thyroid gland. A whole-body thyroid scan will usually be done for this evaluation.

How To Prepare:-
For about a week before a thyroid scan, your doctor may ask you to avoid certain foods and medicines that can interfere with the results, including thyroid hormones and shellfish (which contain iodine). You might have to fast entirely for several hours beforehand if you’ll be given a radioactive iodine pill for the test.You might also need to have blood tests that check thyroid function.

The preparation for a radioactive iodine uptake test is almost the same as for a thyroid scan. However, because you are given radioactive iodine in pill form for an uptake test, you need to wait four to six hours, and possibly as long as a day, before having the scan. (This gives the radioactive iodine time to reach your thyroid.)

Tell your doctor if you:

*Take any medicines regularly. Be sure your doctor knows the names and doses of all your medicines. Your doctor will instruct you if and when you need to stop taking any of the following medicines that can change the thyroid scan test results.

*Thyroid hormones

*Antithyroid medicines

*Medicines that have iodine, such as iodized salt, kelp, cough syrups, multivitamins, or the heart medicine amiodarone (Cordarone, Pacerone)

*Are allergic to any medicines, such as iodine. But even if you are allergic to iodine, you will likely be able to have this test because the amount used in the tracer is so small that your chance of an allergic reaction is very low.

*Have ever had a serious allergic reaction (anaphylaxis) from any substance, such as the venom from a bee sting or from eating shellfish.

*Have had bleeding problems or take blood thinners, such as aspirin or warfarin (Coumadin).

*Have had any test using radioactive materials or iodine dye 4 weeks before the thyroid scan. These other tests may change the results of the thyroid scan.

*Are or might be pregnant.

*Are breast-feeding.

Before a thyroid scan, blood tests may be done to measure the amount of thyroid hormones (TSH, T3, and T4) in your blood.

To prepare for a thyroid scan:

*Do not eat for 2 hours before the test.

*Do not take any antithyroid medicine for 5 to 7 days before the test.

Your doctor may ask you to eat a low-iodine diet, especially if this test is being done to check for thyroid cancer.

Just before the test, you will remove your dentures (if you wear them) and all jewelry or metal objects from around your neck and upper body.

Before a thyroid scan, you need to sign a consent form that says you understand the risks of the thyroid scan and agree to have it done. Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form .

How It Is Done
A thyroid scan is done in the nuclear medicine section of a hospital’s radiology department by a person trained in nuclear medicine (nuclear medicine technologist).

A radionuclide is either injected into a vein or given to you as a pill. Timing of the test then depends on the type of radionuclide your doctor uses, and whether you will also have an uptake test. If you are having only a thyroid scan and your doctor prefers to give a radionuclide by intravenous injection, the scan can be done within 30-60 minutes. If you are given radioactive iodine in pill form, you need to wait four to six hours, and possibly as long as a day, before having the scan. (This gives the radioactive iodine time to reach your thyroid.) If you’re having both a scan and the uptake test, you are likely to receive radioactive iodine in pill form. This allows one radionuclide to be used for both the scan and uptake test, instead of two, and eliminates the need for an injection.

After you’ve received the radionuclide and have waited the appropriate amount of time, a technician places a radioactivity detector-a camera specially designed to take pictures of radioactive objects – against your neck and takes several images. The camera itself doesn’t expose you to any radiation. This portion of the test usually takes about half an hour.

An uptake test only takes several minutes and is performed while you are sitting up. Using a device that resembles a Geiger counter, the doctor or technician places a probe several inches in front of your neck, where the thyroid gland is located, and measures the percentage of radioactivity that is retained by the thyroid gland. You return the next day for follow-up testing to obtain a second set of uptake readings, which are then compared with the first set to determine how much hormone has been formed and secreted in the interim.

If you get technetium, you may feel warm, flushed, and nauseated when it is given. Taking deep breaths to relax may relieve these feelings.

For this test, you will lie on your back with your head tipped backward and your neck extended. It is important to lie still during this test. A special camera (called a gamma scintillation camera) takes pictures of your thyroid gland from three different angles 4 to 6 hours after you took the iodine. The test takes about 10 minutes. Another scan is done again in 24 hours.

After a thyroid scan, you can do your regular activities. But you will be asked to take special precautions when you urinate. This is because your body gets rid of the radioactive tracer through your urine. This takes about 24 hours. It is important to flush the toilet and wash your hands thoroughly after each time you urinate.

How It Feels
You may find it uncomfortable to lie still with your head tipped backward.

How long is it before the result of the test is known?
For the thyroid scan, it takes an hour or more for the pictures to be developed and additional time for a radiologist to examine them. Your doctor will probably receive a report within a day or two. The scan will show the outline, shape, and position of your thyroid so that the doctor can determine whether it is enlarged and whether there are any suspicious growths or nodules. The scan also provides a rough measure of thyroid activity, although this has to be confirmed with a radioactive iodine uptake test.

Uptake test results are available immediately, but because the initial and follow-up readings must be compared, it may take your doctor a day or two to get back to you. To obtain results, your doctor determines an uptake value, which is the net result of how much iodine is picked up by the thyroid, how much is converted to hormone since the time of administration, and how much is either leaked or secreted into the bloodstream. (The thyroid normally secretes hormone in an orderly fashion based on physical needs; leakage is less controlled and indicates that the gland is damaged.) A low reading of radioactivity suggests that your thyroid gland has retained only a small amount of iodine. This generally indicates that the thyroid gland is not producing excess thyroid hormone, but has become inflamed and is unable to properly store the hormone, which then leaks into the bloodstream. A high reading suggests that your thyroid is overactive, producing an excessive amount of thyroid hormone.

A thyroid scan uses a radioactive tracer and a special camera to make a picture of the thyroid gland. The radioactive tracer used in this test is usually iodine or technetium. A thyroid scan is done to help find problems with the thyroid gland.

Thyroid scan  Normal: A normal thyroid scan shows a small butterfly-shaped thyroid gland about 2in. long and 2in. wide with an even spread of radioactive tracer in the gland.

Thyroid scan Abnormal: An abnormal thyroid scan shows a thyroid gland that is smaller or larger than normal. It can also show areas in the thyroid gland where the activity is less than normal (cold nodules) or more than normal (hot nodules). Cold nodules may be related to thyroid cancer.

A whole-body scan will show whether iodine is in bone or other tissue (iodine uptake) after the thyroid gland has been removed for cancer. The whole-body scan can check to see if cancer has spread to other areas of the body.

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Bone Scan

Alternative Names:Scintigraphy – bone

The process of bone growth and renewal is part of your body’s metabolism — natural processes that create and use energy.

Changes in your bone metabolism can be caused by a number of problems. To get a picture of your bone metabolism, your doctor may order a procedure called a bone scan. A radiologist will look for evidence of abnormal metabolism on images from your bone scan.


Your doctor may order a bone scan to help diagnose subtle or hidden bone fractures, such as a stress fracture, that may not show up on a routine X-ray. Bone scans can also help detect other conditions as well. It is a test that detects areas of increased or decreased bone metabolism (turnover). The test is performed to identify abnormal processes involving the bone such as tumor, infection, or fracture.
…...Nuclear Scan->
This is a nuclear scan, also called a radionuclide scan. In a bone scan, a radioactive tracer accumulates in places in your bones with a lot of repair activity. In this way, the tracer is used to identify areas that might be injured due to a fracture, bone infection, arthritis, or invading cancer. The tracer gives off gamma rays, which can be detected using a specialized camera. The camera relays information to a computer to produce images of the bones being scanned. In the images, bright spots appear in the areas where the tracer has collected. Bone scans are most frequently done for people with cancer to see if the cancer has spread to bones.

Why Bone Scan is Done:
Your doctor may order a bone scan to determine whether you have any bone abnormalities that may signify one of the following disorders:

*Paget’s disease of bone
*Bone tumors
*Infection of the joints, joint replacements or bone (osteomyelitis)
*Fibrous dysplasia
*Avascular necrosis or impaired bone blood supply
*Unexplained bone pain

Your doctor may order a bone scan to determine whether cancer, such as prostate, lung or breast cancer, has spread (metastasized) to bone.

How the Test is Performed
A radiotracer (a bone-seeking radioactive material) is injected into vein, so it travels through the bloodstream. As the material wears away, it gives off radiation. This radiation is detected by a camera that slowly scans your body. The camera takes pictures of how much radiotracer collects in the bones.

If a bone scan is done to see if you have a bone infection, images will be taken shortly after the radioactive material is injected, as well as 3 to 4 hours later, when it has collected in the bones. This is called a 3-phase bone scan.

To evaluate metastatic bone disease, images are taken only after the 3 to 4 hour delay.

The scanning part of the test will last about 1 hour and may require you to change positions.

How do you prepare for the test?
No special preparation is required on your part before a bone scan, though you may be asked to remove jewelry or other metal objects. You can eat or drink anything you like before the test.

As with most tests, tell your doctor if you’re pregnant or think you might be pregnant. Bone scans aren’t usually performed on pregnant women because of concerns about radiation exposure to the fetus. You may be asked to wear a hospital gown.

What happens when the test is performed?
The test is performed in the radiology department of a hospital. You will be given a radionuclide. A machine with a specialized camera moves around you. The procedure is painless, but the machine can be noisy. The scan usually takes less than an hour.

There is a small amount of pain when the needle is inserted. During the scan there is no pain. You must remain still during the examination, and you will be instructed when to change positions by the technologist.

You may experience some discomfort due to lying still for a prolonged period of time.

Risk Factor.
The radioactivity you are exposed to is too small to cause side effects or complications except to a fetus. The small amount of radioactivity rapidly diminishes.If you are pregnant or nursing, the test may be postponed to prevent exposing the fetus to radiation.

The amount of radioactivity in the injection is very small, and virtually all activity is gone from the body within 2-3 days.

Although it is extremely rare with bone scanning agents, a person may develop rash, swelling, or anaphylaxis (severe allergic response).

There is a slight risk of infection or bleeding with any intravenous injection. The risk of an allergic reaction to the tracers is extremely rare.

You might find the injection and the need to lie still during the scanning procedure mildly uncomfortable.

Must you do anything special after the test is over?

How long is it before the result of the test is known?
Results are usually available within a few days.

What you can expect
A bone scan falls under the category of nuclear medicine procedures, which means that it uses tiny amounts of radioactive materials called tracers (radionuclides). These tracers accumulate in certain organs and tissues, such as bones. Once introduced into the body, tracers emit a type of radiation called gamma waves, which are detected by a special camera. This camera produces images that are interpreted by radiologists or nuclear medicine specialists.

In a sense, a nuclear procedure such as a bone scan is the opposite of a standard X-ray examination. An X-ray passes radiation into or through your body to create an image on film placed on the other side of your body. In a nuclear scan, the source of radiation is inside your body and travels to the surface, where a camera detects it.

A bone scan can be divided into two basic parts:

*The injection. You will receive an injection of tracers into a vein in your arm, and depending on the reason your doctor orders the scan, images of the injection may be taken immediately. You’ll then wait between two and four hours to allow the tracers to circulate and be absorbed by your bones. You may be allowed to leave the radiology department during this time. Your doctor will ask you to drink extra water to remove unabsorbed radioactive material from your system.

*The scan. During the scan, you’ll be asked to lie still on a table while a machine with an arm-like device supporting the gamma camera passes over your body to record the pattern of tracer absorption by your bones. This is painless. A scan of your entire skeleton takes as long as 60 minutes. Scanning a limited area of your body takes less time.
In some cases, your doctor might order a three-phase bone scan, which includes a series of images taken at different times. A number of images are taken as the tracer is injected, then shortly after the injection, and again three to four hours later.

For certain conditions your doctor might also order additional images called single-photon emission computerized tomography (SPECT). This can help analyze conditions that are especially deep in your bone or in places that are difficult to see with static or two-dimensional (planar) images. The additional SPECT images take approximately 30 minutes.

After the test
Once inside your body, the tracers don’t remain active for long. The radioactivity is eliminated within two days. You should feel no side effects after the procedure, and no aftercare is necessary.

The radiologist looks for evidence of abnormal bone metabolism on the scans. These show up as darker “hot spots” and lighter “cold spots” where the tracers have or haven’t accumulated.

Although a bone scan is very sensitive to abnormalities in bone metabolism, it’s less helpful in determining the exact cause of the abnormality. However, a thorough medical history often reveals the cause, such as a suspected fracture, infection or bone tumor. Other tests may be performed to help establish the diagnosis. For instance, in order to rule out bone cancer, your doctor may need further imaging studies (computerized tomography or magnetic resonance imaging) or a biopsy, which is a sample of bone tissue that’s removed for examination.
Normal Results
Normal distribution areas appear uniform and gray throughout all the bones in your body.

What Abnormal Results Mean
The images should show that the radioactive material has been evenly distributed throughout the body. There should be no

areas of increased or decreased distribution. “Hot spots” are areas where there is an increased accumulation of the radioactive material. “Cold spots” are areas that have taken up less of the radioactive material.


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