5.3 Uses of Radioisotopes

Radioisotop ialah isotop yang tidak stabil
Radioisotope is an Unstable isotope.

Radioisotop Semulajadi Radioisotop Tiruan
Natural Radioisotope: Artificial Radioisotope:
Uranium-235, Uranium-238 dihasilkan apabila nukleus yang stabil dihentam oleh zarah
Carbon-14, Radium-226 alfa, proton atau neutron.
Certain stable nucleus are bombarded by high speed alpha
particles, gamma rays, neutrons or protons.
Beryllium-7, Americium-241

Radioisotop Sinaran yang dipancar Separuh hayat
Carbon-14 Β 5730 tahun
Natrium-24 β 15 jam
Cobalt-60 Β, γ 5.27 tahun
Iodin-131 β 8 hari
Cecium-137 β 30.2 tahun
Bismut-213 α 46 minit
Amerisium-241 α 432 tahun

Ciri-ciri Radioisotop yang digunakan
1. Radioisotop yang memancarkan sinaran gama

- mempunyai kuasa penembusan tinggi
- mempunyai tenaga tinggi untuk membunuh kuman
2. Berada dalam keadaan cecair untuk disuntik dalam salur darah / salur
air atau dalam keadaan gas untuk paip gas
- mudah larut
3. Mempunyai separuh hayat kecil (bidang perubatan)
- supaya mudah mereput kepada atom stabil dalam tempoh bersesuaian
dan kurang berbahaya
- supaya bada pesakit tidak terdedah kepada sinaran radioaktif dalam
tempoh lama.
4. Mempunyai separuh hayat besar (bidang perindustrian)
- jimatkan kos penggunaan sumber bahan radioisotop
5. Menggunakan pengesan Tiub Geiger-Muller
- dapat mengukur bilangan aktiviti / pancaran dengan kejituan yang
tinggi

Industrial • Pengesan asap
• Kawal ketebalan
• Kesan kebocoran paip air bawah tanah

• Pengesan penyakit

Perubatan / Medicine • Pensterilan

• Radioterapi

• Mengesan pengambilan baja dalam akar

Pertanian/ Agriculture • Mengawal serangga perosak

• Radiasi buah supaya tahan lama.

Arkeologi • Pentarikhan karbon / Carbon dating

Di pasang di kilang atau di rumah untuk
mengesan asap daripada kebakaran
Smoke detectors are put in factories or
houses to detect smoke from fires.

Americium - 241

Zarah alpha kerana ia mempunyai kuasa
pengionan yang tinggi.
Alpha particles because they have high
ionization power.

Zarah alfa mengionkan molekul udara. Ion-ion itu bergerak ke
elektrod bertentangan dan mengalirkan arus.
Alpha particles ionized the air molecules. The ions move to the
opposite electrod and small current flow.

Get logic TIDAK
menghalang arus mengalir
dan alarm tidak berbunyi.
NOT’ logic get allows
current to flow and alarm is
triggered.

Input of NOT gate = 1, so
output = 0 and the alarm
will not function.

Apabila asap masuk ke dalam pengesan asap,
zarah asap menyerap zarah alfa. Ini menyebabkan arus yang mengalir dalam
pengesan asap.
When smoke enters the detector, the particles in the smoke absorb some of the
alpha particles. This causes the decrease in the current flows.

Get logic ‘TIDAK’
membenarkan arus
mengalir dan alarm
berbunyi.
NOT’ logic get allows
current to flow and alarm is
triggered.

Input of NOT gate = 0, so
output = 1 and the alarm
will function.

Separuh hayat lama supaya tahan lama dan jimat kos.
Long half life for long lasting and save cost.

Digunakan untuk mengawal:

- Mengawal isian sebatian / makanan dalam bekas

- Mengawal ketebalan kertas atau logam

Sekiranya bacaan radioaktif tinggi, ia menunjukan kandungan

isian atau ketebalan kertas / logam kurang dari nilai standard

yang ditetapkan

Jadi mesin perlu diselaraskan semula kepada nilai yang

dikehendaki.
A radioactive sends radiation through the sheet material as it comes off
the production line.
Beta radiation are used for thin sheets.
A radiation detector on the other side of the sheet measures the
intensity of the radiation passing through the sheet.
The amount of radiation received by the detector depends on the
thickness of the rubber sheet.
If the sheet is too thin, the reading of the detector increases.
A signal is sent from the roller control to the rollers so that the pressure
on the sheets can be reduced.



Sumber radioaktif diletakkan bertentangan
dengan pengesan radioaktif seperti tiub GM.
Kepingan kadbod diletakkan di antara sumber
radioaktif dan tiub GM.
The radioactive source is placed oppositely
with the detector such as GM tube. The
cardboard sheet is in between the source and
detector.

Bacaan berkurang / reading decrease

Kepingan kadbod mengalang zarah beta.
The kadbod block the beta particles.

Penggelek memberi tekanan tambahan. Panjang / long
The roller will press harder.
Tahan lama / last longer.
Strontium-90
Beta
Kuasa penembusan sederhana
Medium penetration power.

Pepejal / solid

Senang menguruskan / easy to handle

position A B C D E F
readings 484 495 600 612 479 500

C and D have high reading, so the plates are
thin because can allow many rays to pass
through.

Check the level of the fruit juice

Develop a system which can control the
volume of the paint in the tin.

Use beta rays Can penetrate the carton and
less dangerous
Use solid radioactive source Easy to handle
Use radioactive which has long So can last longer
half life
Use GM tube as the detector So it can detect beta particles
The radioactive source is put Radioactive detector is put at
upward the opposite side
GM tube is connected to The volume of the paint is
counter/computer calibrated with the computer
If the reading is in the range, so If the reading is out of the range,
receive then it will be rejected

Pengesan kebocoran air pada paip air bawah tanah
Detector for underground water leakage

• Sesuai digunakan pada paip air atau paip gas
• Bahan radioaktif akan disuntik ke dalam paip dan akan

terlarut mengikut aliran bendalir di sepanjang paip itu.
• Sekiranya ada kebocoran, pengesan Geiger-Muller

akan mengesan bacaan radioaktif yang tinggi di
kawasan paip itu kerana sinar radioaktif telah keluar
menerusi lubang kebocoran.

• A radioactive substance which emits beta particles is
added to a fluid in a pipeline to measure the flow rate in
the pipeline and to find leaks.

• The radiation produced by the radioactive substance
can be detected with a GM tube counter placed above
ground.

• A larger increase in the count rate will indicate that
there is leak in that area.

Sumber radioactive yang mengeluarkan zarah
beta dilarutkan bersama air dalam paip air.
Pengesan tiub GM diletakkan di atas tanah
untuk mengesan sinar beta melalui paip air.
A radioactive substance is added to a fluid in a
pipeline. A GM tube detector is placed on the
ground to detect the beta rays through the
pipe line.

Bacaan tinggi / high reading beta

Kuasa penembusan yang sederhana
Medium penetration power

Cecair / liquid
Senang larut / easy to dissolve in water

Short or medium half life Natriumm-24
Separuh hayat pendek atau medium

Memberi masa yang cukup untuk ukuran dan tidak
tinggal lama dalam air.
Provide enough time to make measurement and does
not stay too long in the water.

A larger increase in the count rate will

indicate that there is leak in that area.

Use beta rays Can penetrate the pipe and less
dangerous
Use liquid radioactive source
Use radioactive which has Can dissolve in water
medium half life
long enough to examine
metabolic processes in the
body and short enough to
minimize the radiation dose to
the patient.





Perubatan: Pengesan Radioaktif

Medicine: Radioactive tracers

• Nuclear medicine is a branch of medicine that uses radiation
to provide information about the function of the specific
organs of a patient or to treat disease.

• A radioisotope is taken in by a patient through the digestive
system, by inhalation or through the blood vessels by
injection.

• The radiation emitted enables organs such as thyroid,
bones, heart, liver to be easily imaged by imaging
equipment. Disorders can then be detected.







Menggunakan sinar radioaktif untuk mengkaji
organ pesakit atau mengubat penyakit.
Uses radioactive rays to study the specific
organs or to treat disease.

Menyuntik ke dalam salur darah.
Injection through the blood vessels.

• Digunakan untuk mengesan buah pinggang pesakit yang
tersumbat.

• Pesakit akan disuntik dengan iodin-123

• Dalam masa 5 minit, kedua-dua buah pinggang akan menyerap
iodin-123 dari salur darah dan dipindahkan ke dalam kelenjar
kencing.

• Tiub Geiger Muller akan dihalakan ke buah pinggan pesakit.

• Sekiranya bacaan radioaktif tinggi disebabkan oleh iodin 123
yang tersekat di situ, maka buah pinggang itu akan didiagnosis
sebagai tersumbat.

Buah pinggang kanan kerana masih terdapat
radioisotope dan bacaan masih tinggi.
The right kidney does not functioning. There is
still radioisotope in it. The reading is stiil high.

Separuh hayat medium / medium half life Gamma

Cukup masa untuk mendapatkan bacaan Boleh melepasi badan pesakit tanpa
Enough time to get the reading. membahayakan pengguna.
Can pass through the body without
dangering the user.

Cecair / liquid

Boleh bercampur atau larut dalam
darah dengan mudah
Can be mixed easily with blood.

Kuasa pengionan tinggi, jadi akan Natrium - 24
membunuh sel yang sihat. Kuasa Teknetium-99
penembusan rendah, jadi tidak dapat Xenon-133
dikesan
Ionization power tinggi, so it can kill healthy Iodin - 131
cell. Penetration power low so it cannot
detect by detector. Iodin-123

Peralatan perubatan didedahkan di bawah
sinaran gamma setelah digunakan untuk
membunuh bakteria dan parasite.
Sinar gama digunakan kerana mempunyai
kuasa penembusan yang tinggi dan mampu
membunuh kuman-kuman.
Medical instruments are exposed to gamma
rays after used to kill bacteria and parasite.
Gamma ray is used because it has high
penetration power and capable to kill germs.

Menggunakan sinar gamma untuk membunuh
kuman sel kanser tanpa melakukan
pembedahan.
Use gamma rays to kill cancer cell without
surgery.

gamma

Kuasa penembusan tinggi
High penetration power

Ambil gambar sel cancer menggunakan MR1 atau X-ray. Untuk mengelakkan cell
Kenalpasti kedudukan sel cancer dengan tepat. Pancarkan sinar hidup yang lain
gamma pada target. dimusnahkan./
Take cancer cell image using MR1 or x-ray. Identify the position To avoid other living cells
of cancer cells correctly. Point out gamma ray to the target. from being destroyed.

Dos sinaran yang betul digunakan Masa pendek / short time
Use correct dosage of the ray
Mengelakkan sel hidup daripada
Radiasi berlebihan akan merosakkan banyak dimusnahkan.
sel hidup. Kekurangan radiasi tidak akan To prevent other healthy cells from destroy
memberhentikan kanser daripada merebak
Excessive radiation will damage too many
healthy cells. Insufficient radiation will not
stop the cancer from spreading.

Cobalt-60

Gamma Knive Brain
Surgery

Bahan radioaktif disuntik ke dalam batang pokok
bersama-sama baja fosforus. Kadar penyerapan
baja oleh pokok dapat diketahui dengan
mengesan bacaan tiub GM.
A small amount of radioactive phosphorus is
injected into the stem along with the phosphate
fertilizer. How much fertilizer has been absorbed
by the plant can be studied by detecting the
reading of GM tube

Bahan radioaktif disuntik ke dalam belalang jantan
untuk memandulkan. Kadar pembiakan dapat
dikawal.
Radioactive sources is injected to a male
grasshopper so can control the pest.





The Sterile Insect Technique
(SIT) involves producing a
large number of insects then
irradiating them with gamma
radiation before hatching, to
sterilise them. The sterile
males are then released in
large numbers in the
infested areas. When males
mate with females, no
offspring are produced.
Repeated releases of
sterilised males ensures the
population of the insect pest
in a given area is drastically
reduce.

How food irradiation works Food Iradiation
Food irradiation is similar to
X-raying luggage at airports. Benefits of food irradiation
The food is conveyed Kills bacteria, insects and parasites that
through a thick-walled can cause food-borne diseases.
chamber that contais a • Extends the short life of food by
source of ionizing radiation
that passes through the destroying the micro-organisms that
food, destroying insects, cause spoilage and slowing the
bacteria and micro- ripening process and inhibiting the
organisms. Many irradiators sprouting of root vegetables such as
use Cobalt-60 as the source potatoes and onions.
of radiation. • Makes food safe to eat by destroying
parasites and micro-organisms that
cause
• Ensures that insects are not
transported across borders through
quarantine treatments of fruits and
vegetables.



Kegunaan radioisotope dalam bidang arkeologi
Uses of radioisotopes in archeology

• Carbon-14 is a radioisotope with a
half-life of 5730 years and decays by
emitting beta particles.

• Living animals and plants have a
known proportion of carbon-14 in
their tissues which remains constant.

• When living things die, the amount of
carbon-14 in their body decreases at a
known rate.

• The amount of carbon-14 left in a
decayed plant or animal can be used
to tell its age.

Carbon – 14

Masih kekal sama / remain the same.
Kandungan carbon semakin menurun.
The proportion of carbon-14 decreases.

Umur sesuatu tulang dapat diketahui dengan 14 N 01n164C 11H
mengukur kandungan carbon-14 yang tinggal. 7
Kemudian bandingkan dengan carbon-14
dalam tulang yang masih hidup. 164C174N 10e
The age of a bone can be determined by
measuring the amount of carbon 14 left. After
that compare the amount of carbon 14 in the
bone which is still alive.