PET CT SCAN - All you need to know

What is a PET CT scan?

                                         

This advanced nuclear imaging technique combines positron emission tomography (PET) and computed tomography (CT) into one machine. A PET/CT scan reveals information about both the structure and function of cells and tissues in the body during a single imaging session.

A PET CT scan can identify changes in functioning of organs at a very early stage, often before structural changes take place. The study utilizes small amounts of radioactive tracers, which when injected into the body, give information about different body functions.

How is it different from CT or MRI?

CT, MRI and other radiological modalities like X ray, ultrasonography are structural imaging modalities, which means, they look at the size and shape of organs and other body structures.

PET imaging on the other hand, looks at functions within the body.

Hence when combined with CT, they give more information than a CT or MRI alone and pick up altered function due to disease process at a much earlier stage, before structural changes happen.

Why have I been recommended a PET CT scan?

The commonest use of this scan is in cancers, where it is used to detect and identify the areas of spread of the cancer, monitor response to treatment or plan for radiotherapy, or to guide biopsy.

PET CT scanning can also be used to evaluate certain heart diseases or neurological conditions.

Is PET safe ?

                                                     

The risks associated with PET scan are very low. PET scan involves a very small amount of radioactive tracer injected into your body which decays by itself with time and is also excreted out by the body continuously through urine. The total radiation exposure during a PET CT scan roughly equals two CT scans of abdomen and pelvis.

The injected contrast material used for the CT part of the study may cause some allergy rarely, in a few patients.

Family members of the patient undergoing the scan are not at risk due to radiation because most of the radioactive medicine injected decays by the time the scan is over.

However, this radioactive exposure carries a risk for a pregnant woman carrying an unborn child and any radioactive tests should not be performed during pregnancy. Please inform your doctor before the procedure if you suspect to be pregnant.

What happens during a PET scan? Is it painful?

                  

A PET CT scanner machine is quite similar to a CT machine and not a closed tunnel like MRI.

The patient is asked to come fasting for the test and an intravenous canulla is placed in one of the peripheral veins (on hands or arms usually). The radioactive tracer is injected and the patient is asked to rest in an isolation area for a stipulated time (usually 60-120 minutes) and sip some oral contrast material. The most commonly used radioactive tracer (Fluorodeoxyglucose) is an inert substance and does not cause any interaction or side effects in the body.

The scanning procedure per se is painless and intravenous CT contrast may or may not be used during the scan, as per the need and physician’s discretion. 

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Author- 

   

Dr.Sugandha Dureja

Founder Member,
MBBS, DNB, FEBNM
Fellow Theranostics (Germany)
At. Consultant, Nuclear Medicine
FMRI, Gurgaon
CNETS India.
Also Yoddhas Medical Expert Panelist

MEDICAL BLOGS:LYMPHOMAS

Lymphoma is cancer that begins in infection-fighting cells of the immune system, called lymphocytes. These cells are in the lymph nodes, spleen, thymus, bone marrow, and other parts of the body. When you have lymphoma, lymphocytes change and grow out of control.

                                      

There are two main types of lymphoma:
Every type of lymphoma grows at a different rate and responds differently to treatment.
Scientists don't know what causes lymphoma in most cases.
  *When did you first notice changes?
  * Do you have pain? Where?
  * How is your appetite?
  * Have you lost any weight
  * Do you feel tired or weak?
  * Have you ever been treated for lymphoma or another cancer?
  * Do you have any infections or illnesses?
  * Do any cancers run in your family?
You might get a lymph node biopsy to check for cancer cells. For this test, your doctor will remove all or part of a lymph node, or use a needle to take a small amount of tissue from the affected node.
These include:
   * Immunophenotyping
   * Flow cytometry
   * Fluorescence in situ hybridization testing
Classification systems generally classify lymphoma according to:
1)  Whether or not it is a Hodgkin lymphoma
2) Whether the cell that is replicating is a T cell or B cell
3) The site from which the cell arises

CT scan or PET scan imaging modalities are used to stage a cancer.
   * What stage is my cancer?
   * Have you treated people with this kind of lymphoma before?
   * What treatments do you recommend?
   * How will the treatments make me feel?
   * What will help me feel better during my treatment?
   * Are there any complementary treatments I could consider, along with the medical care? Are there any I should avoid?
The main treatment for non-Hodgkin lymphoma are:
   * Chemotherapy. It uses drugs to kill cancer cells.
   * Radiation therapy. It uses high-energy rays to destroy cancer cells.
   * Immunotherapy. It uses your body's own immune system to attack cancer cells.
   * Radiation therapy
   * An autologous transplant uses your own stem cells.
   * An allogeneic transplant uses stem cells taken from a donor
Treatment for these types of lymphoma typically consists of aggressive chemotherapy, including the CHOP or R-CHOP regimen. A number of people are cured with first-line chemotherapy
Most relapses occur within the first two years, and the relapse risk drops significantly thereafter.
For people who relapse, high-dose chemotherapy followed by autologous stem cell transplantation is a proven approach.
Advanced Hodgkin disease requires systemic chemotherapy, sometimes combined with radiotherapy. Chemotherapy used includes the ABVD regimen, which is commonly used in the United States. Other regimens used in the management of Hodgkin lymphoma include BEACOPP and Stanford V. Encouragingly, a significant number of people who relapse after ABVD can still be salvaged by stem cell transplant.
Lymphoma treatment can cause side effects. Talk to your medical team about ways to relieve any symptoms you have.
Also ask your doctor about changes to your diet and exercise that will help you feel better during your treatment. Ask a dietician for help if you're not sure what types of food to eat. Exercises like walking or swimming can relieve fatigue and help you feel better during treatments like chemotherapy and radiation. You might also try alternative therapies like relaxation, yoga, meditation to relieve the pain.
  * The kind of lymphoma you have
  * How far the cancer has spread
  * Your age
  * The type of treatment you get
  * Other associated health problems you may have.

·      Non-Hodgkin: Most people with lymphoma have this type.

·      Hodgkin

Non-Hodgkin and Hodgkin lymphoma each affect a different kind of lymphocyte. 

Even though lymphoma is cancer, it is very treatable.

Causes:

You might be more likely to get it if you:

·      Are in your 60s or older

·      Are male

·       Have a weak immune system from HIV/AIDS, an organ transplant, or because you were born with an immune disorder

·       Have an immune system disease such as rheumatoid arthritis, Sjogren's syndrome, lupus, or celiac disease

·       Have been infected with a virus such as Epstein-Barr, hepatitis C virus, T- cell leukemia/lymphoma (HTLV-1), or human herpesvirus 8 (HHV8)

·       Have a close relative who had lymphoma

·      Were exposed to benzene or chemicals that kill bugs and weeds

·       Were treated for Hodgkin or non-Hodgkin lymphoma in the past

·       Were treated for cancer with radiation

Symptoms:

·      Swollen glands (lymph nodes), often in the neck, armpit, or groin

·       Cough

·       Shortness of breath

·       Fever

·      Night sweats

·      Stomach pain

·      Fatigue

·       Weight loss

·      Itching

Getting a Diagnosis

Before you have any tests, your doctor will want to know:

Your doctor will check you for signs of lymphoma and will feel for swollen lymph nodes. This symptom doesn't mean you have cancer. Most of the time, an infection unrelated to cancer causes swollen lymph nodes.

You might also have one of these tests to see how far the lymphoma has spread:

·      Blood test. 

·      Bone marrow aspiration or biopsy. Your doctor uses a needle to remove fluid or tissue from your bone marrow, to look for lymphoma cells.

·      Chest X-ray.

·      MRI..

·      PET scan. It uses a radioactive substance to look for cancer cells in your body

·       Molecular test. It looks for changes to genes, proteins, and other substances in cancer cells to help your doctor figure out which type of lymphoma you have.

Several classification systems have existed for lymphoma, which use histological and other findings to divide lymphoma into different categories. The classification of a lymphoma can affect treatment and prognosis

Hodgkin lymphoma

Hodgkin lymphoma is one of the most commonly known types of lymphoma and differs from other forms of lymphoma in its prognosis and several pathological characteristics. It is marked by the presence of a type of cell called the Reed Sternberg cell.

Non-Hodgkin lymphomas

Non-Hodgkin lymphomas include all lymphomas, except Hodgkins lymphoma, and are more common than Hodgkin lymphoma. A wide variety of lymphomas are in this class, and the causes, the types of cells involved, and the prognosis vary by type. The incidence of non-Hodgkin lymphoma increases with age. It is further divided into several subtypes.

STAGING OF CANCER:

After a diagnosis and before treatment, a cancer is staged. This helps to determine, if the cancer has spread, and if so, whether locally or to distant sites. Staging is reported as a grade between I (confined) and IV (spread).Staging is carried out because the stage of a cancer impacts its prognosis and treatment.

The Ann Arbor staging system is routinely used for staging of both HL and NHL. In this staging system, I represents a localized disease contained within a lymph node, II represents the presence of lymphoma in two or more lymph nodes, III represents spread of the lymphoma to both sides of the diaphragm, and IV indicates tissue outside a lymph node.

Questions You Can Ask Your Doctor

   *What type of lymphoma do I have?

Treatment

The treatment you get depends on what type of lymphoma you have and how far it has spread.

The main treatments for Hodgkin lymphoma are:

   * Chemotherapy

If these treatments don't work, you might have a stem cell transplant. First you'll get very high doses of chemotherapy. This treatment kills cancer cells, but it also destroys stem cells in your bone marrow that make new blood cells. After chemotherapy, you will get a transplant of stem cells to replace the ones that were destroyed.

Two types of stem cell transplants can be done:

Many low-grade lymphomas remain indolent for many years. Treatment of an assymptomatic patient is often avoided. In these forms of lymphoma, such as follicular lymphoma, watchful waiting is often the initial course of action as the risks of treatment outweigh the benefits.

Treatment of more aggressive, forms of lymphoma can result in a cure in the majority of cases, but the prognosis for patients with a poor response to therapy is worse.

Hodgkin lymphoma typically is treated with radiotherapy alone, as long as it is localized.

Taking Care of Yourself:

Your outlook depends on:

Getting Support

·      You can get support from people who have gone through this kind of illness.

·      Contact the Leukemia & Lymphoma Society or Lymphoma Research Foundation to learn more.

·      Team Yoddhas online support group in India

Thanks for reading and please keep visiting our blog to discover and appreciate more Yoddhas. 
Feel free to contact the Yoddhas team at team@yoddhas.com 
Join our free patients group https://www.facebook.com/groups/yoddhathewarrior/

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Author- 

   

Dr. Gayatri Bhat

Doctor , blood cancer survivor and a member of Yoddhas Medical Expert Panel

MEDICAL BLOGS:NON SMALL CELL LUNG CANCER

Staging of NSCLC ( Lung Cancer)

The stage of a cancer describes how far the cancer has spread. The treatment and outcome depends largely on the stage the cancer is in. The clinical stage is based on the results of physical exams, biopsy report, imaging tests (CT scan, chest x-ray, PET scan, etc.), and other tests. Pathologic stage is determined after surgery, which is based on the same factors as above, plus the findings observed during the surgery. 

The clinical and pathologic stages might be different in some cases. *It is larger than 3 cm across but not larger than 7 cm.  *It involves a main bronchus, but is not closer than 2 cm to the carina (the point where the windpipe splits into the left and right main bronchi). *It has grown into the membranes that surround the lungs (visceral pleura). *The tumor partially clogs the airways, but this has not caused the entire lung to collapse or develop pneumonia. *It has grown into the chest wall, the breathing muscle that separates the chest         from the abdomen (diaphragm), the membranes surrounding the space between the two lungs (mediastinal pleura), or membranes of the sac surrounding the heart (parietal pericardium). *It has grown into a main bronchus and is closer than 2 cm to the carina, but it does not involve the carina itself. *It has grown into the airways enough to cause an entire lung to collapse or to cause pneumonia in the entire lung.  *Two or more separate tumor nodules are present in the same lobe of a lung. Two or more separate tumor nodules are present in different lobes of the same lung. The cancer has spread to the other lung. Cancer cells are found in the fluid around the lung (called a malignant pleural effusion). Cancer cells are found in the fluid around the heart (called a malignant pericardial effusion). Once the T, N, and M categories have been assigned, this information is combined to assign an overall stage of 0, I, II, III, or IV. This process is called stage grouping. Some stages are subdivided into A and B. The stages identify cancers that have a similar outlook (prognosis) and thus are treated in a similar way. Patients with lower stage numbers tend to have a better outlook.   *The tumor has grown into a main bronchus, but is not within 2 cm of the carina (and it        is not larger than 5 cm).  * The tumor has grown into the visceral pleura (the membranes surrounding the lungs) and is not larger than 5 cm.   *The tumor is partially clogging the airways (and is not larger than 5 cm).    *The cancer has not spread to lymph nodes or distant sites. The cancer has not spread to lymph nodes or distant sites. Two or more separate tumor nodules are present in different lobes of the same lung. It may or may not have spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). Any affected lymph nodes are on the same side as the cancer. It has not spread to distant sites. Two or more separate tumor nodules are present in different lobes of the same lung. The cancer has also spread to lymph nodes around the carina (the point where the windpipe splits into the left and right bronchi) or in the space between the lungs (mediastinum). Affected lymph nodes are on the same side as the main lung tumor. It has not spread to distant sites. OR The cancer can be any size and may or may not have grown into nearby structures or reached nearby lymph nodes. It has spread to distant lymph nodes or to other organs such as the liver, bones, or brain.

At the time of surgery the Onco surgeon may find cancer in an area that did not show up on imaging tests, which might give the cancer a more advanced pathologic stage.

TNM Staging System: (which is based on T(Tumour size), N( spread to local Node) & M (Metastasis to other organs).

The most common sites of metastasis are the brain, bones, adrenal glands, liver, kidneys, and the other lung.

Numbers or letters appear after T, N, and M to provide more details about each of these factors. Higher numbers mean the cancer is more advanced.

Details of the TNM staging system

The TNM staging system is complex and can be hard for most patients (and even some doctors) to understand.If you have any questions about the stage of your cancer, ask your doctor to explain it to you.

   T categories for lung cancer (TX, TO, T1-4)

·      TX: The main (primary) tumor can’t be assessed, or cancer cells were seen on sputum cytology or bronchial washing but no tumor can be found.

·      TO: There is no evidence of a primary tumor.

·      Tis: The cancer is found only in the top layers of cells lining the air passages. It has not invaded into deeper lung tissues. This is also known as carcinoma in situ.

·      T1: The tumor is no larger than 3 centimeters (cm) across, has not reached the membranes that surround the lungs (visceral pleura), and does not affect the main branches of the bronchi.

           If the tumor is 2 cm or less across, it is called T1a.

          If the tumor is larger than 2 cm but not larger than 3 cm across, it is called T1b.

·      T2: The tumor has 1 or more of the following features:

          If the tumor is 5 cm or less across, it is called T2a.

          If the tumor is larger than 5 cm across (but not larger than 7 cm), it is called T2b.

·      T3: The tumor has 1 or more of the following features:

*It is larger than 7 cm across.

·      T4: The cancer has 1 or more of the following features:

A tumor of any size that has grown into the space between the lungs (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe (trachea), the tube connecting the throat to the stomach (esophagus), the backbone, or the carina.

    N categories for lung cancer ( NX, NO, N1-3)

·      NX: Nearby lymph nodes cannot be assessed.

·      N0: There is no spread to nearby lymph nodes.

·      N1: The cancer has spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). Affected lymph nodes are on the same side as the primary tumor.

·      N2: The cancer has spread to lymph nodes around the carina (the point where the windpipe splits into the left and right bronchi) or in the space between the lungs (mediastinum). Affected lymph nodes are on the same side as the primary tumor.

·      N3: The cancer has spread to lymph nodes near the collarbone on either side, and/or spread to hilar or mediastinal lymph nodes on the side opposite the primary tumor.

M categories for lung cancer (MO, M1)

·      M0: No spread to distant organs or areas. This includes the other lung, lymph nodes further away than those mentioned in the N stages above, and other organs or tissues such as the liver, bones, or brain.

·      M1a: Any of the following:

·      M1b: The cancer has spread to distant lymph nodes or to other organs such as the liver, bones, or brain.

Overall Stage for lung cancer ( Stage 0,I - IV) which is based on the TNM stage:

Occult (hidden) cancer

TX, N0, M0: Cancer cells are seen in a sample of sputum or other lung fluids, but the cancer isn’t found with other tests, so its location can’t be determined.

Stage 0

Tis, N0, M0: The cancer is found only in the top layers of cells lining the air passages. It has not invaded deeper into other lung tissues and has not spread to lymph nodes or distant sites.

Stage IA

T1a/T1b, N0, M0: The cancer is no larger than 3 cm across, has not reached the membranes that surround the lungs, and does not affect the main branches of the bronchi. It has not spread to lymph nodes or distant sites.

Stage IB

T2a, N0, M0: The cancer has 1 or more of the following features:

   *The main tumor is larger than 3 cm across but not larger than 5 cm.

Stage IIA

Three main combinations of categories make up this stage.

1)    T1a/T1b, N1, M0: The cancer is no larger than 3 cm across, has not grown into the membranes that surround the lungs, and does not affect the main branches of the bronchi. It has spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). These lymph nodes are on the same side as the cancer. It has not spread to distant sites.

OR

2)    T2a, N1, M0: The cancer has 1 or more of the following features:

·      The main tumor is larger than 3 cm across but not larger than 5 cm.

·      The tumor has grown into a main bronchus, but is not within 2 cm of the carina (and it is not larger than 5 cm).

·      The tumor has grown into the visceral pleura (the membranes surrounding the lungs) and is not larger than 5 cm.

·      The tumor is partially clogging the airways (and is not larger than 5 cm). 

·      The cancer has also spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). These lymph nodes are on the same side as the cancer. It has not spread to distant sites.

OR

3)    T2b, N0, M0: The cancer has 1 or more of the following features:

·      The main tumor is larger than 5 cm across but not larger than 7 cm.

·      The tumor has grown into a main bronchus, but is not within 2 cm of the carina (and it is between 5 and 7 cm across).

·      The tumor has grown into the visceral pleura (the membranes surrounding the lungs) and is between 5 and 7 cm across.

·      The tumor is partially clogging the airways (and is between 5 and 7 cm across). 

·      The cancer has not spread to lymph nodes or distant sites.

Stage IIB

Two combinations of categories make up this stage.

1)    T2b, N1, M0: The cancer has 1 or more of the following features:

·      The main tumor is larger than 5 cm across but not larger than 7 cm.

·      The tumor has grown into a main bronchus, but is not within 2 cm of the

carina (and it is between 5 and 7 cm across).

·      The tumor has grown into the visceral pleura (the membranes surrounding the lungs) and is between 5 and 7 cm across.

·      The cancer is partially clogging the airways (and is between 5 and 7 cm across). 

·      It has also spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). These lymph nodes are on the same side as the cancer. It has not spread to distant sites.

OR

2)    T3, N0, M0 The main tumor has 1 or more of the following features

·      It is larger than 7 cm across.

·      It has grown into the chest wall, the breathing muscle that separates the chest from the abdomen (diaphragm), the membranes surrounding the space between the lungs (mediastinal pleura), or membranes of the sac surrounding the heart (parietal pericardium).

·      It invades a main bronchus and is closer than 2 cm (about ¾ inch) to the carina, but it does not involve the carina itself.

·      It has grown into the airways enough to cause an entire lung to collapse or to cause pneumonia in the entire lung.

·      Two or more separate tumor nodules are present in the same lobe of a lung.

Stage IIIA

Three main combinations of categories make up this stage.

1)    T1 to T3, N2, M0: The main tumor can be any size. It has not grown into the space between the lungs (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe (trachea), the tube connecting the throat to the stomach (esophagus), the backbone, or the carina. It has not spread to different lobes of the same lung.

The cancer has spread to lymph nodes around the carina (the point where the windpipe splits into the left and right bronchi) or in the space between the lungs (mediastinum). These lymph nodes are on the same side as the main lung tumor. The cancer has not spread to distant sites.

OR

2)    T3, N1, M0: The cancer has 1 or more of the following features:

·      It is larger than 7 cm across.

·      It has grown into the chest wall, the breathing muscle that separates the chest from the abdomen (diaphragm), the membranes surrounding the space between the lungs (mediastinal pleura), or membranes of the sac surrounding the heart (parietal pericardium).

·      It invades a main bronchus and is closer than 2 cm to the carina, but it does not involve the carina itself.

·      Two or more separate tumor nodules are present in the same lobe of a lung.

·      It has grown into the airways enough to cause an entire lung to collapse or to cause pneumonia in the entire lung.

·      It has also spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). These lymph nodes are on the same side as the cancer. It has not spread to distant sites.

OR

3)    T4, N0 or N1, M0: The cancer has 1 or more of the following features:

A tumor of any size has grown into the space between the lungs (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe (trachea), the tube connecting the throat to the stomach (esophagus), the backbone, or the carina.

Stage IIIB

Two combinations of categories make up this stage.

1)    Any T, N3, M0: The cancer can be of any size. It may or may not have grown into nearby structures or caused pneumonia or lung collapse. It has spread to lymph nodes near the collarbone on either side, and/or has spread to hilar or mediastinal lymph nodes on the side opposite the primary tumor. The cancer has not spread to distant sites.

OR

2)    T4, N2, M0: The cancer has 1 or more of the following features:

A tumor of any size has grown into the space between the lungs (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe (trachea), the tube connecting the throat to the stomach (esophagus), the backbone, or the carina.

Stage IV

Two combinations of categories make up this stage.

1)    Any T, any N, M1a: The cancer can be any size and may or may not have grown into nearby structures or reached nearby lymph nodes. In addition, any of the following is true:

·      The cancer has spread to the other lung.

·      Cancer cells are found in the fluid around the lung (called a malignant pleural effusion).

·      Cancer cells are found in the fluid around the heart (called a malignant pericardial effusion).

2)    Any T, any N, M1b: The cancer can be any size and may or may not have grown into nearby structures or reached nearby lymph nodes. 

It has spread to distant lymph nodes or to other organs such as the liver, bones, or brain.

Thanks for reading and please keep visiting our blog to discover and appreciate more Yoddhas. 
Feel free to contact the Yoddhas team at team@yoddhas.com 
Join our free patients group https://www.facebook.com/groups/yoddhathewarrior/

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Author- 

   

Dr. Ganjoo 

Head-Yoddhas Medical Expert Panel