Question

Answer true or false. (a) Of the radioisotopes listed in Table $9-5,$ the majority decay by beta emission. (b) Isotopes that decay by alpha emission are rarely if ever used in nuclear imaging because alpha emitters are rare. (c) Gamma emitters are so widely used in medical imaging because gamma radiation is penetrating and, therefore, can easily be measured by radiation detectors outside the body. (d) When selenium-75 ( $_{34}^{\text {75 }}$ Se ) decays by electron capture and gamma emission, the new nucleus formed is arsenic- $75\left(\begin{array}{c}75 \\ 34\end{array}\right)$ (e) When iodine-131 $\left(\frac{131}{53} \mathrm{I}\right)$ decays by beta and gamma emission, the new nucleus formed is xenon-131 $\left(\begin{array}{c}131 \\ 54\end{array}\right)$ (f) In positron emission tomography (a PET scan), the detector counts the number of positrons emitted by a tagged material and the location within the body where the tagged material accumulates. (g) The use of 18 -fluorodeoxyglucose (FDG) in PET scans of the brain depends on the fact that FDG behaves in the body as does glucose. (h) A goal of radiation therapy is to destroy pathological cells and tissues without at the same time damaging normal cells and tissues. (i) In external beam radiation, radiation from an external source is directed at a tissue either on the surface of the body or within the body. (j) In internal beam radiation, a radioactive material is implanted in a target tissue to destroy cells in the target tissue without doing appreciable damage to surrounding normal tissues.

Name: Problem 50, Chapter 9: Introduction to General, Organic and Biochemistry
Uploaded: 2021-06-08T13:03:57-08:00
Duration: 7 min 13 s
Channel: David Collins

   Answer true or false.
(a) Of the radioisotopes listed in Table $9-5,$ the majority decay by beta emission.
(b) Isotopes that decay by alpha emission are rarely if ever used in nuclear imaging because alpha emitters are rare.
(c) Gamma emitters are so widely used in medical imaging because gamma radiation is penetrating and, therefore, can easily be measured by radiation detectors outside the body.
(d) When selenium-75 ( $_{34}^{\text {75 }}$ Se ) decays by electron capture and gamma emission, the new nucleus formed is arsenic- $75\left(\begin{array}{c}75 \\ 34\end{array}\right)$
(e) When iodine-131 $\left(\frac{131}{53} \mathrm{I}\right)$ decays by beta and gamma emission, the new nucleus formed is xenon-131 $\left(\begin{array}{c}131 \\ 54\end{array}\right)$
(f) In positron emission tomography (a PET scan), the detector counts the number of positrons emitted by a tagged material and the location within the body where the tagged material accumulates.
(g) The use of 18 -fluorodeoxyglucose (FDG) in PET scans of the brain depends on the fact that FDG behaves in the body as does glucose.
(h) A goal of radiation therapy is to destroy pathological cells and tissues without at the same time damaging normal cells and tissues.
(i) In external beam radiation, radiation from an external source is directed at a tissue either on the surface of the body or within the body.
(j) In internal beam radiation, a radioactive material is implanted in a target tissue to destroy cells in the target tissue without doing appreciable damage to surrounding normal tissues.

Introduction to General, Organic and Biochemistry

Frederick A.… 11th Edition

Chapter 9, Problem 50

Instant Answer

Solved by Expert David Collins

06/08/2021

Step 1

Step 1: We need to evaluate each statement based on the information provided in the question and our knowledge of nuclear chemistry. Show more…

Show all steps

Thanks for your feedback!

Answer true or false. (a) Of the radioisotopes listed in Table $9-5,$ the majority decay by beta emission. (b) Isotopes that decay by alpha emission are rarely if ever used in nuclear imaging because alpha emitters are rare. (c) Gamma emitters are so widely used in medical imaging because gamma radiation is penetrating and, therefore, can easily be measured by radiation detectors outside the body. (d) When selenium-75 ( $_{34}^{\text {75 }}$ Se ) decays by electron capture and gamma emission, the new nucleus formed is arsenic- $75\left(\begin{array}{c}75 \\ 34\end{array}\right)$ (e) When iodine-131 $\left(\frac{131}{53} \mathrm{I}\right)$ decays by beta and gamma emission, the new nucleus formed is xenon-131 $\left(\begin{array}{c}131 \\ 54\end{array}\right)$ (f) In positron emission tomography (a PET scan), the detector counts the number of positrons emitted by a tagged material and the location within the body where the tagged material accumulates. (g) The use of 18 -fluorodeoxyglucose (FDG) in PET scans of the brain depends on the fact that FDG behaves in the body as does glucose. (h) A goal of radiation therapy is to destroy pathological cells and tissues without at the same time damaging normal cells and tissues. (i) In external beam radiation, radiation from an external source is directed at a tissue either on the surface of the body or within the body. (j) In internal beam radiation, a radioactive material is implanted in a target tissue to destroy cells in the target tissue without doing appreciable damage to surrounding normal tissues.

Play audio

Feedback

David Collins and 65 other subject Chemistry 101 educators are ready to help you.

Ask a new question

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Radioactive Decay Modes

This concept covers the various ways in which an unstable nucleus releases energy to reach a more stable configuration. It includes processes like alpha decay, beta decay, electron capture, and gamma emission. Understanding these decay modes is fundamental to nuclear medicine, as they determine the types of radiation emitted and their suitability for imaging or therapy.

Beta Emission

Beta emission is a type of radioactive decay in which a nucleus emits a beta particle (an electron or positron) as it transforms into a more stable form. In medical applications, beta emitters can be used for therapeutic purposes or as part of diagnostic procedures, depending on the energy and penetration capability of the emitted particles.

Alpha Emission and Nuclear Imaging

Alpha emission involves the release of a helium nucleus from a decaying atom, and it is characterized by high energy but low penetration. In nuclear medicine, alpha emitters are less commonly used for imaging because their short-range limits their ability to be detected externally, although they may have applications in targeted therapies.

Gamma Emission

Gamma emission refers to the process in which a nucleus emitting no charge releases a high-energy photon, which is highly penetrating. This characteristic makes gamma rays particularly useful in medical imaging, as they can traverse body tissues and be detected by external sensors, enabling imaging techniques such as single-photon emission computed tomography (SPECT).

Electron Capture

Electron capture is a decay process in which a proton in the nucleus captures an inner-shell electron, leading to a conversion of the proton to a neutron and often resulting in the emission of characteristic gamma rays. This process is significant in nuclear medicine, both for its role in altering the nuclide and in providing a means to detect the decay via gamma emissions.

Positron Emission and PET Imaging

Positron emission involves the emission of a positron (the antimatter counterpart of the electron) during radioactive decay. In positron emission tomography (PET), the emitted positrons encounter electrons, leading to annihilation events that produce detectable gamma photons. This method is central to PET imaging, allowing for precise location imaging of radiolabeled compounds in the body.

Use of FDG in PET Scans

Fluorodeoxyglucose (FDG) is a radiolabeled glucose analog commonly used in PET imaging because it mimics glucose behavior in the body. Tissues with high metabolic activity, such as the brain or cancerous tissues, preferentially uptake FDG, enabling the visualization of metabolic processes and aiding in the diagnosis of various conditions.

Radiation Therapy Principles

In radiation therapy, the goal is to maximize damage to pathological tissues, such as tumors, while minimizing exposure and harm to normal tissues. This principle underlies the careful planning and delivery of radiation doses, whether using external or internal methods, to achieve effective therapeutic outcomes.

External Beam Radiation Therapy

External beam radiation therapy involves directing radiation from a source outside the body toward the targeted tissue. This method is commonly employed to treat tumors located on or near the surface or within internal organs, and it requires precise targeting to avoid collateral damage to surrounding healthy tissues.

Internal Beam Radiation Therapy

Internal beam radiation therapy, also known as brachytherapy, involves the placement of radioactive materials directly within or near the tumor. By localizing the source of radiation, this method aims to deliver high doses to the target tissue while reducing exposure to adjacent normal tissues, thus minimizing side effects.

Recommended Videos

Transcript

00:01 This question is another series of statements that you're asked to identify as true or false.

00:07 These types of questions can serve as very good reviews for the concepts found in this section when preparing for an exam.

00:15 Statement a of the isotopes listed in table 95, the majority decay by beta emission.

00:24 The isotopes in table 95 correspond to those that are commonly used for medical purposes or medical.

00:31 Diagnoses.

00:33 And if you look close, there are a lot of betas, but some of those betas actually refer to a positron because they have a positive charge associated with them.

00:47 So we can't count these.

00:53 If we then count the ones that do that our beta emission, we're looking at only four out of the 13.

01:00 That's definitely not the majority.

01:04 So this would be false.

01:06 Statement b, i isotopes that decay by alpha emission are rarely if ever used in nuclear imaging because alpha emitters are rare.

01:15 Well if we look at table 95 we do not find any alpha emitters.

01:23 So the question then becomes is it because they are rare or is it because they are dangerous and alpha alpha emitters although have low penetration if ingested have very, very high ionization potential.

01:41 So it's really not because they're rare.

01:43 There are many radioactive isotopes that are alpha emitters.

01:47 Alpha emission is quite common.

01:50 So this statement would be false.

01:52 They're not used because they're dangerous, not because they're rare.

01:58 Statement c, gamma emitters are so widely used in medical imaging because gamma radiation is penetrating and therefore can easily be measured by radiation detectors outside of the body.

02:11 Yes, this would be true.

02:12 If gamma emitters can penetrate, then once they're in the body, the gamma radiation, which can penetrate, can leave the body easily and be detected by a radiation detector outside the body.

02:26 So this statement is true.

02:29 Statement d.

02:30 When selenium 75 decays by electron capture and gamma emission, the nucleus that is formed is arsenic 75.

02:40 Well, selenium 75 has an at times.

02:44 Number of 34.

02:46 If you look closely, you'll notice it in this question.

02:49 They are also stating that arsenic has atomic number 34.

02:53 Right there, you can identify this statement as false because we can't have two elements with the same atomic number...

Ace is your personal tutor. It breaks down any question with clear steps so you can learn.

Start Using Ace