I've seen MRIs ordered with a notation of "r/o" in the context of "r/o
recurring tumor". What does r/o represent in this context?

BTW, enjoyed the site; content, navigation and usability are very good ..
nice job!

GJ 24 Jan 2003

Thank you for your enquiry and feedback. The “r/o” normally means "rule out". You may notice another "abbreviation" - TRO meaning "to rule out". 

Editor
 

I understand that a new device called the "pill camera" can be swallowed and used to view the alimentary canal without the need to do a colonoscopy. Please let me know when this will be available in Malaysia and where.

YS Yap 18 June 2002

The camera pill is not intended to replace standard endoscopic studies of the alimentary canal (oesophagus, stomach, small and large intestine). In fact, the camera pill has not been studied for use in the large intestine (colon) and is currently unable to replace colonoscopy.  

It is not available in Malaysia currently.  According to Professor Dato’ Dr K.L Goh of University Malaya Medical Centre in Kuala Lumpur, it is an expensive device and would probably not be available in the near future. Before the device can be adopted for standard use, many issues including practicality would also have to be ironed out. 

Brief Information on the Camera Pill

On 1^st August 2001, the US Food and Drug Administration cleared for marketing a small capsule-sized camera (specifically the Given Diagnostic Imaging System) that is intended for visualisation of the small bowel (small intestine – the intestine between the stomach and the large intestine/colon). This is the segment of bowel (except for the most proximal, i.e. the duodenum) that the upper oesophagogastroduodenoscopy cannot reach. The colonoscopy only visualises the large bowel(colon).  

Barium studies (especially the small bowel enema) have thus far been the mainstay of imaging the small intestine (bowel). Barium studies are able to give motility information, pattern of “distribution” in the abdominal cavity as well as other signs such as narrowing (stricture), fistula (an abnormal connection between one part of the small intestine to another structure in the abdomen), thickening of the bowel wall and growths within the intestinal wall.  For abnormal bleeding (for example from an abnormal blood vessel) in this segment of the bowel, an angiogram (contrast study of the blood vessels supplying the intestines) is normally carried out. The other test is a special radionuclide scan. 

This disposable camera pill is shaped just like a normal pill capsule and contains a camera, transmitter, battery and a light source. It is swallowed and will be propelled through the intestines by the normal peristaltic waves. The patient can go home after taking the “pill” but returns the next day to the hospital with the data recorder. The cost of this camera pill is about the cost of an endoscopic procedure in the USA. 

The camera pill is able to take pictures of the lining of the small intestine twice a second as the pill passes through the small intestine. These pictures are transmitted to the receiver (data recorder) that is in a belt worn round the waist of the patient.  The data is then transferred to the computer for analysis.  

This device (which runs on battery power that can last up to 8 hours) is for adding information and not replacing current methods of evaluating the small intestine. It therefore acts as a complementary procedure with specific indications as decided by the physician/doctor.  The camera pill cannot be used in known or suspected intestinal obstructions, fistulas or strictures. Patients with unexplained anaemia or blood in their stool may be candidates for this if the usual endoscopic or radiological examinations cannot diagnose the problem.

Check out the latest updates on this here!

KML, 24 Nov 2002

(The email message is not reproduced as it is very long and is one person’s account. It is entitled – “ One Woman’s Story on Soya – Interesting Facts”. It ends with a warning that the dangers of soya have not been widely circulated and that heavy consumers of soya may actually be endangering their health.)

Soya was first cultivated in China (as early as 3000 B.C.) but is now widely grown in the USA. It is a staple food in many countries and has valuable constituents including protein, isoflavones, saponins and phytosterols. It is low in fat, cholesterol free and soya protein provides essential amino acids (almost all that animal protein provides). As such, it is a favourite food for vegetarians/vegans. 

Soya is also an ingredient in many manufactured food products, used in salad dressings, as an emulsifier in some chocolates and even in flour.  

Soya has been used in connection with high cholesterol control, alleviating menopause symptoms as well as reduce risks of cancer and osteoporosis. The first long term bone density study on the effects of soymilk in post menopausal women showed that after 2 years, those drinking the isoflavone-rich soymilk appeared to prevent bone loss in the lumbar spine compared to the control group that did not receive the isoflavones. 

This form of dietary protein also appears to have a positive impact on end-stage kidney disease – delaying the onset of end-stage kidney disease and also improve the nutritional status of patients on haemodialysis.  

Other emerging areas for soya use includes its possible use in the reduction of age spots, protecting the skin from dehydration and inhibiting hair growth. In Asia, soy has been used as a cleanser. 

Anti Cancer properties of Soy
Studies on soy and prostate cancer also appears to suggest that soy isoflavones can stabilize the disease and inhibit tumour growth in prostate cancer.  In one study (San Francisco Bay), soy-based foods were associated with a reduced risk of thyroid cancer in women. (Horn, Ross et al, 2001) 

As for breast cancer, the majority of the data suggests that soy is beneficial for the prevention of the disease. Genistein is an estrogen-like compound formed from isoflavones, which are phytochemicals in soy.  Isoflavones appear to regulate estrogen levels and hence its recommendation for use in the control of post menopausal symptoms. Coral Lamartiniere of the University of Alabama studied the anticancer properties in rats and reported his findings in a major breast cancer research conference in Florida in September 2002. Although he has only demonstrated soy’s anticancer benefits (specifically genistein) in rats (early in life and then, again in adulthood – showed lower incidence of mammary cancer), he would recommend parents to ensure their prepubescent daughters eat soy products daily.  

Safety Issues in Soya consumption?
There is no evidence to suggest that soya intake at the usual levels are harmful in healthy individuals. Just as any food product or medicine, there are always risks and benefits.  

Soya is in the group of foods known as goitrogens (eg cabbages are in the same food group). By the inhibition of an enzyme which makes the T3 and T4 thyroid hormones, there is a possibility of developing goiter and autoimmune thyroiditis. However, this will only occur in very high intakes of soy isoflavones and or when the diet is deficient in iodine. Soy products has been a staple diet in Asian countries for hundreds years with no significant occurrence of goiter amongst Asians. Goitre is primarily due to a deficiency in iodine. It is best to screen for thyroid dysfunction once over the age of 35 years, especially in women to ensure there is no potential adverse effect. 

Soy products in babies? Soy milk is given in babies with allergy to cow’s milk or to vegans who do not wish to consume cows’ milk. Currently there is no evidence that soy milk formulae will cause problems in babies. Dr Thomas Badger of the Arkansas Children’s Nutrition Centre has concluded that early exposure to soy supports normal growth, development, bone mineralization and immune response. A follow up study of Dr Badger’s did not show adverse effects in adolescents and young adults who consumed soy as infants. However, in the infant with congenital hypothyroidism, the use of soy milk formula must be under the care of a Paediatric Endocrinologist. Today’s soy milk formula is also fortified with iodine. 

Allergies to soy products are possible and such people should avoid soy products. As for drug interactions, always discuss your use of soya with current medications with your doctor. 

To eat or not to eat soya products?
The body of evidence suggests that it is safe to eat soya products as part of a balanced diet. It is very unlikely that at the usual levels of consumption in a healthy individual, one will suffer from the adverse effects of some of its properties, such as estrogenic as well as goitrogenic properties.  

Soya is not the only goitrogen around – vegetables of the cabbage family also are goitrogens. As for estrogenic properties, there is a big group of “herbal supplements” such as motherwort leaf, saw palmetto berry, Rhodiola rosea root, red clover blossom, dang gui root, black cohosh and blue cohosh, vitex berry, hops flower, wild yam, licorice root with similar effects. Therefore care must also be taken if one has or is at risk for uterine or breast cancers. 

The same principle applies- to maintain good health, and help reduce risks of cancers and other diseases, all aspects of a healthy lifestyle should be looked into. Adequate exercise, eat a healthy balanced diet, avoid alcohol, do not smoke! 

Further reading:

1. www.ifrn.bbsrc.ac.uk/public/FoodInfoSheets/soya.html

2. www.hollandbarrett.com/Supp/Soy.htm

3. www.abcnews.go.com/onair/2020/2020_000609_soyfdaletter_feature.html

4. Fourth International Symposium on the Role of Soy in Preventing and Treating Chronic Disease

I understand that the amount of radiation from a CT scan is equivalent to about 400 X-rays.

I hope that you can let me know answers to the following:

1. How long will it take for the radiation from a lung CT scan to be completely discharged from the body.

2. How does the body get rid of the radiation from a CT scan.

3. at present when a doctor/specialist orders a CT scan for a patient, he often don't ask if the patient has done any such scans recently; this may cause the patient to receive an overdose of radiation. Such things can happen especially as medicine is now a very specialise field with different specialists dealing in different fields. A patient may be seeing a few of them. Thank you.

YS Yap, 2 July 2002

Background information on CT, Radiation and Nuclear Medicine

For a brief introduction to computed tomography, please read the article on it in the section on Radiology Inside the Human Body. (www.radiologymalaysia.org/archive/RITHB/CT.htm)

Radiation involved in CT scanner are x-rays. As such, there is no situation where the radiation needs to be “discharged” from the body. This is different from radionuclide scans (please click here to read introduction to Nuclear Medicine) where radioactive substances are introduced into the body to diagnose disease. In this case, the radioactive substance has a half life (depending on the type of radioactive substance) and will also undergo “excretion” from the body, usually in the urine.  

For a better understanding of radiation, please read the article Radiation by clicking here.  

Requests for CT scans – is there a danger of overdose?
As long as any procedure utilises radiation, we should be judicious in the use of that procedure. In the consideration of radiation dose control, there are 2 main issues.

1.       Is the procedure justified? In other words, is it absolutely necessary for diagnosis and therefore management of the patient. If it is, then, there is no question that the procedure needs to be done. Sometimes, the referring doctor will discuss with the radiologist what is the best method for arriving at, confirming the diagnosis or following up the patient. Sometimes, the procedure is a radiologically guided procedure for treatment of the patient. For example in children, if an ultrasound is able to get enough information, it will be used instead of x-rays or CT. However, in certain situations, the only test that best gives the answers required may be a CT scan. Sometimes, more than one modality of imaging is needed.

2.       Principle of ALARA – As Low As Reasonably Achievable. This means when the procedure is done, the method selected, used and the steps taken must be to ensure that the minimum amount of radiation is involved in the process of obtaining good quality diagnostic images in the social and economic setting of a particular country. 

Radiation Dose in CT scan
Your quote of 400 xrays does not refer to what CT scan nor does it mention which body part  x-ray it is comparing with. Today there are many types of CT scans (spiral, multislice, electron beam) and the issue of radiation dose is not quite as simple.  

Based on a survey carried out in the 1989 a CT of the chest or abdomen would be equivalent to about 400 Chest radiographs (CXRs).  (Quoted from “Making the Best Use of a Department of Clinical Radiology published by The Royal College of Radiologists, London, Second Edition 1993). A CXR would be equivalent to about 3 days of natural background radiation.

However, radiation dose in CT scans is not that simple as the scanning parameters, the use of contrast media, the primary aim of the CT scan and organs of interest, whether early, and delayed phases are used as well as the type of CT scanner used will influence final dose received by the patient.  In addition, it is not only the total dose received that should be considered but the radiosensitivity of the organs in question also play a role. 

Justification for CT Scan or other radiological procedures
To conclude, questions that one needs to satisfy are:

1. Does the patient need the radiological procedure?
2. Does the patient need it now?
3. Has it been done already?
4. Has the problem been explained clearly to the Radiologist or discussed thoroughly? This is important that the right procedure, films and views are done.
5. Is this the best radiological study for this particular patient’s problem?

Once these questions are satisfied, then the procedure will have to be done, even if the patient recently had other investigations using radiation. At the end of the day, it is always a BENEFIT vs RISK assessment.  The question of “radiation overdose” rarely arises in today’s modern diagnostic imaging. However, you have raised a pertinent issue, doctors should ask if there have been previous investigations so that these investigations are not repeated unnecessarily, unless new information are needed or investigations to further evaluate a problem needs to be done. - Editor

Please let me know whether FDG PET Scan is available. If not, when is the
earliest it will be available.  

Winston 25th Oct 2001

PET FDG – Positron Emission Tomography with FDG is not available in Malaysia yet.  The University Malaya Medical Centre Nuclear Medicine Department plans to acquire a Cyclotron soon (possibly in 2002). A cyclotron is essential before Pet FDG can be done.

Dr Sulaiman Tamanang (Consultant Radiologist and Nuclear Medicine Specialist)

Editor: The following articles on nuclear medicine have been added to the website for the benefit of our other readers.

• Radiology In The Human Body - Nuclear Medicine

• PET FDG

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Tuesday, 04 January 2005