radioactivity assignment physical science medicine … · radioactivity assignment nuclear medicine...

NUCLEAR

MEDICINE Radioactivity Assignment

PHYSICAL SCIENCE

NUCLEAR

MEDICINE Radioactivity Assignment

PHYSICAL SCIENCE

Radioactivity Assignment Nuclear Medicine

2

Nuclear medicine is a branch of medicine which is generally used to both treat and diagnoses illnesses

and diseases in a safe/painless way. Nuclear medicine procedures allow the determination of medical

information which may otherwise be unavailable, require surgery or more expensive tests. The use of

nuclear medicine generally can make identifications of illnesses or abnormalities extremely early in

the progression of the illness- long before other practices could identify it. The factor of early

detection allows a disease/illness to be treated earlier, posing a higher chance of recovery (What Is

Nuclear Medicine? 2017).

Nuclear medicine is used for two primary purposes: diagnosis and therapy (ACR, 2017).

Diagnosis is generally referred to as imaging, and is only used to diagnose and establish what the

illness the patient is affected by is. Therapy is used to treat a patient from illnesses, again using

radioactive materials to accomplish said goal.

Nuclear medicine imaging uses minute amounts of radioactive materials, referred to as radiotracers,

and they are typically injected into the bloodstream, inhaled or swallowed. (ACR, 2017)

The radiotracer uses small amounts of radioactive dye to highlight concerning areas (such as cancer

cells or infection). Pictures can then be taken of the areas for closer analysis and treatment. ("Nuclear

Medicine Scans" 2017) The radiotracer is introduced to the body either through injection, inhalation

or consumption. The dye travels through the body, gathering in the area of the body which is under

examination. When the dye is eventually collected in a tumour or organ, it makes energy in the form

of gamma rays. In order to identify the gamma rays, a scanner or camera captures images based off

the gamma ray output. Nuclear medicine scan pictures can detail the function as well as the structure

of tissues and organs in the body. (ACR, 2017). The radioactive material present in the body will

decay over time, posing no risk to the patient.

As with any branch of medicine, there are many smaller sectors and ways to perform nuclear

medicine. Each type of testing has a different purpose, some working better on different types of

organs or illnesses to identify the issue.

Bone or Joint Scans:

Bone or join scan are utilised to find out if there are any abnormalities within the bones or joints. As

per usual, a small amount of radioactive material is injected into the vein, which are then taken up by

the skeletal system. Pictures are captured 2-3 hours’ post injection. ("Full Body Bone Scan | Nuclear

Medicine | Services & Treatments (Copy) | Premier Radiology" 2017)

Gallium Scan:

Gallium scans are used to identify infections or tumour. Small amounts of radioactive gallium are


3

injected into the patient. Pictures are captured using a specialised camera. Dependent on the patients’

medical history, imaging will generally be at either 24, 48, or 72 hours’ post injection of the

radioactive material. (Gallium Scan: Medlineplus Medical Encyclopedia". 2017. Medlineplus.Gov.

https://medlineplus.gov/ency/article/003450.htm.) Gallium scans generally use gallium-67, an isotope

of gallium, which is commonly found in multiple salts like citrate and nitrate. The gallium-67

generally releases a spectrum of gamma rays (93, 185, 288, 394 KeV energy), and has a half-life of

approximately 78 hours. This type of scan has recently been largely replaced by 18-F FDG PET/CT

imaging which has earlier scans, better image quality and SUV quantification. (Venkatesh 2017)

Gallium-67 Citrate is used for the scans, and has a chemical structure of:

The radioactive decay equation for Gallium-67 is:

67

31𝐺𝑎∗ →

67

31𝐺𝑎 +

0

0𝛾 + 𝑒𝑛𝑒𝑟𝑔𝑦


4

The above photo shows the electron capture decay of Ga-67, which occurs in the body throughout

gallium scans. The isotope slowly decays into Zn-67 which is stable, unlike the radioactive Ga-67.

A gallium scan is shown above.


5

Gastric Emptying:

Gastric emptying is used to evaluate the functioning of the stomach and digestive system. The patient

will either eat a scrambled egg and begin imaging immediately, taking 2 hours, or drink a glass of

water and then imaging will begin immediately for 60 minutes. ("Gastric Emptying Scan" 2017)

Oesophageal Reflux Study:

This test is used to find out if liquid material moves in a reverse direction from the stomach or the

oesophagus, also commonly known as reflux. In this case, a small amount of the radioactive liquid is

mixed with a drink the patient must consume. A binder is then placed on the abdomen to place

pressure on the stomach. Pictures are then captured. ("CT Risks A Hot Topic On Social Media |

Atlantic Medical Imaging" 2017)

Hepatobiliary Scan:

These scans are used to analyse gall bladder function, as well as the bile ducts. The patient is injected

with radiotracers, which are then taken up by bile-producing glands. Pictures are taken immediately

for a minimum of one hour, and possibly up to three hours. (“Hepatobiliary (HIDA) Scan | Nuclear

Medicine”, 2017)

Liver or Spleen Scan:

This test is mainly used to find out the size and function of the liver and spleen. A small amount of

radioactive material is injected into the vein. Pictures of the liver and spleen are taken. ("Liver-Spleen

Scan" 2017)

Meckel’s Scan:

This study is undertaken to discover if the patient has a Meckel’s diverticulum, a slight bulge in the

small intestine present from birth. This study is frequently performed on children. Pictures are

captured after the injection for a period of about 45 minutes. ("Test Preparation- Meckel's

Diverticulum Scan" 2017)


6

Image: A Meckel’s scan result

MUGA Scan:

MUGA scans are used to judge the function of the heart, often performed on customers who will be

receiving chemotherapy. To perform this, the patient generally has a small amount of blood drawn,

which is taken and mixed with the radioisotope tracker. This mixture is consequently reinjected into

the patient and imaging begins approximately 10 minutes later. The test then takes about one hour.

("Multigated Acquisition Scan (MUGA)" 2017) The imaging takes photos of the heart with each

pump to find out how well the heart is functioning and how much blood pumps with each beat. It

generally only captures images of the lower chambers of the heart and reports abnormalities in the

size of the chambers (ventricles), as well as abnormalities in the movement of blood through the heart.

It is also taken before chemotherapy to find any pre-existing heart conditions. It is common for cancer

survivors who have had radiation therapy to the chest, spine or upper abdomen, as well as people who

have had a bone marrow/stem cell transplant or certain types of chemotherapy. ("MUGA Scan"

2017). Technetium-99m is generally used for this form of imaging (“Radionuclide

Angiogram/MUGA Scan”, 2017). Technetium-99m has a gamma decay equation of:


7

𝑇𝑐99𝑚 → 𝑇𝑐99 +0

0𝛾

Renal Scan:

Renal scans are used to assess blood flow as well as the level at which kidneys are functioning in the

patients. A computer is used to graph the level of blood flow and function of the kidneys. Pictures are

collected for a period of 30 minutes. ("Renal Scan" 2017)

SPECT Brain Scan:

This test is unusual in comparison to the others as it’s a two-part test. The first part involves an

injection. An IV is placed into the patients arm and the medication will be administered through it,

taking around 30 minutes. The patient can leave between the two tests but must return around an hour

and a half later for the remainder of the testing (imaging). The imaging portion of the testing takes

about 45 minutes. ("SPECT Brain Imaging: Background, Indications, Contraindications" 2017)

SPECT Liver Scan (Red Blood Cell Scan of Liver):

This is often undertaken as a follow-up of a CT scan, MRI or Ultrasound to rule out a benign (dead)

liver tumour (haemangioma). This is also a two-part test. The first portion will take approx. 30

minutes. The technologist will again draw a small sample of blood, and then reinject it into the patient

after mixing it with the isotope. Again, the patient may leave but must return 1.5 hours afterwards for

imaging. The imaging will take around 45 minutes. ("Types Of Nuclear Medicine" 2017)


8

Both SPECT scans are less commonly referred to as a single-photon emission computerised

tomography scans, and let a doctor analyse the function of internal organs (“Why its’s Done” –Mayo

Clinic”, 2017).

Thyroid Scan and Uptake (Radionuclide Iodine Uptake):

This examination determines how well the thyroid gland is functioning by taking a measurement of

the uptake of iodine by the thyroid gland. Pictures of the thyroid gland are also taken during the

process of testing. The test is performed over two days. On the first day, the patient must consume a

radioactive iodine pill, and is asked to return in 6 hours for the first analysis of Iodine uptake, as well

as the first imaging process. On the second day, the patient is asked to return for a 24-hour uptake

measurement. At this point, the radiologist reviews the test and determines whether the thyroid gland

requires examination. At this point, there may be more images of the gland obtained post review of

the results and physical examination (ACR, 2017).

Nuclear medicine can also be used in a therapeutic method. Therapy is performed using unsealed

radioactive sources, and can treat ailments from illnesses of the thyroid, pain relief of bone metastasis

to treatment of cancer (Therapeutic Nuclear Medicine, 2017). Research into fresh

radiopharmaceuticals to treat different tumours and illnesses is always being consistently undertaken

(Research, SNMMI, 2017). Radiation therapy is one of the more prominent examples of therapeutic

nuclear medicine. It uses ionising radiation to kill cancerous cells, as well as to shrink the tumour. It

does this through damaging the cell’s DNA, which then stops the cells from performing mitosis- that

is, the process of growing and dividing. The most commonly used way of exposing the cells to

radiation is through external radiation therapy, which consists of a limited area of the body being

exposed to a beam of especially high-energy x-rays to the main tumour. However, targeted

radionuclide therapy is more commonly used as it is systematic treatment- much alike chemotherapy.

Targeted therapy using radiopharmaceuticals consists of radioactive compounds commonly used in

nuclear medicine for treatment, which primarily is used in cancer cells which migrated from primary

tumours to lymph nodes/secondary organs like bone marrow. The recently distributed tumour cells are

generally difficult to treat because there are intense changes in the number of targetable receptors in

each cell.

It uses molecules labelled with a radionuclide to deliver a lethal level of radiation to the

tumour/disease site. A distinctive feature to the radionuclides is that they can employ a ‘bystander’ or

‘crossfire’ effect (as shown below), which then can kill surrounding tumour cells even if they aren’t

fully developed- i.e., don’t have the tumour-associated antigen or receptors (Medicine, 2017).


9

As shown above, the differences between external beam radiation therapy and targeted radionuclide

therapy are extreme, as the external beam therapy requires knowledge of locations of tumour, whereas

the radionuclide therapy only requires knowledge of the tumour biology, and can exterminate any

surrounding tumour as well as the known tumour itself (Advancing Nuclear Medicine Through

Innovation, 2007).


10

Radionuclide Therapy:

The biological effect from the therapy is obtained by energy taken in from the radiation released from

the radionuclide. Contrary to how the nuclides used for the nuclear medicine imaging emit gamma

rays, which have high penetration levels, the radionuclides used for targeted radionuclide therapy

must release radiation with a short path length. There are three types of radiation that work for

targeted radionuclide therapy- beta particles, alpha particles (diagram below) and Auger electrons,

which can- respectively- irradiate tissue volumes with multicellular, cellular and subcellular

dimensions. Within these categories, there are various radionuclides in a variety of tissue ranges, half-

lives and chemistries, which presents a striking possibility of finding the perfect properties for a

targeted radionuclide to be utilised for each individual patient. Further development in this field is

pushed forward by the desire to move away from nonspecific noxious therapies regularly used in

oncology and forward to less toxic targeted treatments (Medicine 2017).

In some cases, mixed emitters are utilised to complete both imaging and therapy with the same

radionuclide (for example- the mixed beta/gamma emitter iodine-131). Iodine and its isotopes can

only be used for thyroid problems, as the thyroid cells are the only cells in the body that can absorb

iodine (De Jorgen and Nandurkar 2017). Iodine-131 is a highly reactive radioisotope, with an

extremely short half-life of 8.02 days. As it is highly reactive, it is frequently used in minute doses for

thyroid cancer therapies. Despite it being used in low doses for medical examinations, it is an ideal

tracer for use in humans. This is because only a few radioactive atoms need to be injected into the

bloodstream for the path of the iodine to be efficiently monitored. The atoms combine with molecules

which will then transform into thyroid gland hormones. From that point gamma ray scintigraphy

(imaging) then can monitor the thyroid activity and report any abnormalities. However, in recent

times, Iodine-131 use has decreased due to favour of an alternate isotope, Iodine-132. As mentioned

earlier, Iodine-131 is also commonly used for treatment of thyroid cancers. In these cases, stronger

doses of Iodine-131 are injected into the bloodstream in the same manner, and the subsequent beta


11

particles, due to the trajectory of their released beta particles, guarantee that the radiation only affects

a moderately small part of the body ("Radioactivity : Iodine 131" 2017).

Iodine decays through a process of beta decay with the formula of:

131

53I →

131

54𝑋𝑒 +

0

−1𝑒

Iodine decays with a process of beta decay, and the emitted beta particles are emitted as well as

Xenon, which is then used to image and/or treat the medical issue.

Another common radioisotope used for medical imaging is technetium-99m, which is a metastable

radioactive tracer isotope. It has a gamma ray energy of around 140KeV, which is increasingly

convenient to use for detection of any issues with bodily functions. It has both an extremely short

physical and biological half-life, which means it is very quick to clear from the body following

imaging. It also only has gamma energy and is not accompanied by alpha/beta emission, which allows

for a more exact alignment of imaging detectors.

Isotope

Half-lives in days

TPhysical TBiological TEffective

99mTc 0.25 1 0.20

The above table shows the half-life of Technetium-99m.

As Technetium-99m is produced by bombarding molybdenum-98 with neutrons, the resultant

molybdenum-99 decays with a half-life of 66 hours into the metastable state of Tc.

𝑇𝑐99𝑚 → 𝑇𝑐99 +0

0𝛾


12

This process allows production of Technetium-99m for medical purposes. Technetium-99m is strange

as it has a half-life of 6.03 hours for gamma emission. This is excessively long for an electromagnetic

decay circumstance. As it has such a long half-life leading to this decay, the state is called metastable,

hence the ‘99m’ designation ("Technetium-99M" 2017). The diagram below exemplifies the aspects

of the complex decay of Technetium-99m.


13

Technetium-99m decays through beta decay from Molybdenum-99:

99

42𝑀𝑜 → 𝑇𝑐99𝑚+ -1e

It then goes through gamma decay to become Technicium-99.

𝑇𝑐99𝑚 → 𝑇𝑐99 +0

0𝛾

Technicium-99m is used in 35million procedures per year, and accounting for around 80% of all

nuclear medicine procedures worldwide- making it a very popular choice to use for diagnosis and

treatment ("Radioisotopes In Medicine" 2017).

Nuclear medicine is used frequently to provide diagnosis of any abnormalities before physical

symptoms are shown and visibly noticeable, meaning it becomes significantly easier for the patient to

receive successful treatment. It’s ability to allow for immediate, accurate diagnosis makes it


14

irreplaceable, as well as the fact that it can detect diseases in extremely early stages. It also has an

ability to treat as well as diagnose.

However, there are always risks and negatives to any medical endeavour. The main risk is to the

health of infants, toddlers, elderly peoples and pregnant women. It is also an extremely expensive

process- as the machines which take the photos tend to be excessively expensive, making it hard for it

to be easily accessible as not every hospital/doctors surgery. However, with the huge advantages to

nuclear medicine, these risks are outweighed and it has since become a vital aspect of the medical

world.

References:

(ACR), Radiological. 2017. "Nuclear Medicine, General". Radiologyinfo.Org.

https://www.radiologyinfo.org/en/info.cfm?pg=gennuclear.

(ACR), Radiological. 2017. "Thyroid Scan And Uptake". Radiologyinfo.Org.

https://www.radiologyinfo.org/en/info.cfm?pg=thyroiduptake.

(ACR), Radiological. 2017. "Thyroid Scan And Uptake". Radiologyinfo.Org.

https://www.radiologyinfo.org/en/info.cfm?pg=thyroiduptake.

"CT Risks A Hot Topic On Social Media | Atlantic Medical Imaging".

2017. Atlanticmedicalimaging.Com. http://www.atlanticmedicalimaging.com/pages/types-

nuclear-medicine.

"Full Body Bone Scan | Nuclear Medicine | Services & Treatments (Copy) | Premier Radiology".

2017. Premierrad.Com. http://www.premierrad.com/nuclear-med-bodyscan.

"Gallium Scan: Medlineplus Medical Encyclopedia". 2017. Medlineplus.Gov.

https://medlineplus.gov/ency/article/003450.htm.

"Gastric Emptying Scan". 2017. Healthline. http://www.healthline.com/health/gastric-emptying-scan.

"Hepatobiliary (HIDA) Scan | Nuclear Medicine". 2017. Riainvision.Com.

http://www.riainvision.com/exams/hida_scan.aspx.

"Liver-Spleen Scan". 2017. Newcastlenuclearmedicine.Com.Au.

http://www.newcastlenuclearmedicine.com.au/site/index.cfm?display=105580'.

"Liver-Spleen Scan". 2017. Newcastlenuclearmedicine.Com.Au.

http://www.newcastlenuclearmedicine.com.au/site/index.cfm?display=105580'.

Lombardo, Crystal. 2015. "Pros And Cons Of Nuclear Medicine". Vision Launch.

http://interactive.snm.org/docs/whatisnucmed2.pdf.


15

"Multigated Acquisition Scan (MUGA)". 2017. Cleveland Clinic.

http://my.clevelandclinic.org/health/articles/multigated-acquisition-scan-muga.

"Nuclear Medicine Scans". 2017. Curesearch For Children's Cancer. https://curesearch.org/Nuclear-

Medicine-Scans.

"Radionuclide Ventriculography Or Radionuclide Angiography (MUGA Scan)". 2017. Heart.Org.

http://www.heart.org/HEARTORG/Conditions/HeartAttack/SymptomsDiagnosisofHeartAttack/

Radionuclide-Ventriculography-or-Radionuclide-Angiography-MUGA-

Scan_UCM_446354_Article.jsp#.WOyMGRir3q0.

"Renal Scan". 2017. Imagingpathways.Health.Wa.Gov.Au.

http://www.imagingpathways.health.wa.gov.au/index.php/consumer-info/imaging-

procedures/renal-scan.

"Role Of Radionuclide Imaging In The Diagnosis Of Postoperative Infection | Radiographics".

2017. Pubs.Rsna.Org. http://pubs.rsna.org/doi/full/10.1148/radiographics.20.6.g00nv101649.

"SPECT Brain Imaging: Background, Indications, Contraindications".

2017. Emedicine.Medscape.Com. http://emedicine.medscape.com/article/2064780-overview.

"SPECT SCANS: Why It's Done". 2017. Mayo Clinic. http://www.mayoclinic.org/tests-

procedures/spect-scan/details/why-its-done/icc-20303156.

"Test Preparation- Meckel's Diverticulum Scan". 2017. Svcmi.Com.Au.

http://www.svcmi.com.au/meckels-diverticulum-scan-st-vincents-clinic.html.

"Types Of Nuclear Medicine". 2017. Atlanticmedicalimaging.Com.

http://www.atlanticmedicalimaging.com/pages/types-nuclear-medicine.

#31 - Gallium - Ga". 2017. Hobart.K12.In.Us.

https://www.hobart.k12.in.us/ksms/PeriodicTable/gallium.htm.

"All About Gallium Scans". 2017. Healthline. http://www.healthline.com/health/gallium-

scan#overview1.

Brady, Darren, Joe M. O’Sullivan, and Kevin M. Prise. 2017. "What Is The Role Of The Bystander

Response In Radionuclide Therapies?".

http://journal.frontiersin.org/article/10.3389/fonc.2013.00215/full.

De Jorgen, Claire, and Dee Nandurkar. 2017. "Iodine-131 Therapy". Insider Radiology.

https://www.insideradiology.com.au/iodine-131-therapy/.


16

"Gallium Scan". 2017. Little Fighters Cancer Trust.

https://littlefighterscancertrust.wordpress.com/tests-procedures/gallium-scan/.

"Hepatobiliary (HIDA) Scan | Nuclear Medicine". 2017. Riainvision.Com.

http://www.riainvision.com/exams/hida_scan.aspx.

"JPNM Ga-67". 2017. Med.Harvard.Edu.

http://www.med.harvard.edu/jpnm/physics/isotopes/Ga/Ga67/Ga67.html.

Lombardo, Crystal. 2017. "Pros And Cons Of Nuclear Medicine - Vision Launch". Vision Launch.

http://visionlaunch.com/pros-and-cons-of-nuclear-medicine/#.

Medicine, National. 2017. "Targeted Radionuclide Therapy". Ncbi.Nlm.Nih.Gov.

https://www.ncbi.nlm.nih.gov/books/NBK11464/.

"MUGA Scan". 2017. Cancer.Net. http://www.cancer.net/navigating-cancer-care/diagnosing-

cancer/tests-and-procedures/muga-scan.

"Radioactivity : Iodine 131". 2017. Radioactivity.Eu.Com.

http://www.radioactivity.eu.com/site/pages/Iodine_131.htm.

"Radioisotopes In Medicine". 2017. World-Nuclear.Org. http://www.world-nuclear.org/information-

library/non-power-nuclear-applications/radioisotopes-research/radioisotopes-in-medicine.aspx.

"Radionuclide Angiogram/MUGA Scan". 2017. Scai.Org.

http://www.scai.org/SecondsCount/Tests/detail.aspx?cid=7698443f-7dd1-4706-8475-

d446b1a3ecf6.

"Research | SNMMI". 2017. Snmmi.Org. http://www.snmmi.org/research/.

"Technetium-99M". 2017. Hyperphysics.Phy-Astr.Gsu.Edu. http://hyperphysics.phy-

astr.gsu.edu/hbase/Nuclear/technetium.html.

"Therapeutic Nuclear Medicine". 2017. Rpop.Iaea.Org.

https://rpop.iaea.org/RPOP/RPoP/Content/InformationFor/HealthProfessionals/3_NuclearMedici

ne/TherapeuticNuclearMedicine/.

"Value Of Gallium-67 Scanning In Monitoring Therapeutic Effectiveness In A Patient With

Relapsing Polychondritis - Sciencedirect". 2017. Sciencedirect.Com.

http://www.sciencedirect.com/science/article/pii/S1607551X0870161X.

Venkatesh, M. 2017. "Gallium 67 Scintigraphy". Radiopaedia.Org.

https://radiopaedia.org/articles/gallium-67-scintigraphy.


17

What Is Nuclear Medicine?. 2017. Ebook. 1st ed. Society of Nuclear Medicine.

http://interactive.snm.org/docs/whatisnucmed2.pdf.

"Why It's Done - Mayo Clinic". 2017. Mayo Clinic. http://www.mayoclinic.org/tests-

procedures/spect-scan/details/why-its-done/icc-20303156.

Advancing Nuclear Medicine Through Innovation. 2007. 1st ed. Washington, D.C.: National

Academies Press.

Medicine, National. 2017. "Targeted Radionuclide Therapy". Ncbi.Nlm.Nih.Gov.

https://www.ncbi.nlm.nih.gov/books/NBK11464/.

"Nuclear Medicine | Radiology". 2017. Med.Nyu.Edu. https://med.nyu.edu/radiology/about-nyulmc-

radiology/subspecialty-sections/nuclear-section.

"Digication E-Portfolio :: Various Animal Physiologies Related To Physics :: Nuclear".

2017. Login.Digication.Com.

https://login.digication.com/session?return=https%3A%2F%2Fmercy.digication.com%2Fauth%

2Fcallback.digi%3Freturn%3D%252Fvarious_animal_physiologies_related_to_physics%252FQ

uantum.

"Can You Write The Nuclear Decay Equation For The Beta Decay Of Iodine-131? | Socratic".

2017. Socratic.Org. https://socratic.org/questions/can-you-write-the-nuclear-decay-equation-for-the-

beta-decay-of-iodine-131-b-and-.

"Meckel Diverticulum Imaging: Overview, Radiography, Computed Tomography".

2017. Emedicine.Medscape.Com. http://emedicine.medscape.com/article/410644-overview.

radioactivity assignment physical science medicine … · radioactivity assignment nuclear medicine...

Documents