Radiopharmaceuticals
Updates to Article Attributes
Radiopharmaceuticals are drugs that are bound to radioactive substances. The pharmaceutically active portion determinesThey may be used for diagnostic imaging, as therapeutic agents, or both (theranostic).
In some cases, such as Iodine-123, the activityradioactive molecule itself has a physiologic distribution that will be measured andallows it to image the target organ. In others, the radioactive portion emits radiation that can be measured byof the scannermolecule is used primarily to tag and provide an imaging method for the pharmaceutically-active portion, which changes the biological distribution. One example of this is I-123 MIBG.
A number of radiopharmaceuticals are used in human imaging. They share the physical characteristic of emitting radiation of various kinds. In some cases theThe particles emitted particlesfrom diagnostic radiopharmaceuticals are detected either directly or indirectly by specialised equipment (e.g. SPECT, PET, gamma camera, etc.) to generate imaging. In other cases, the agent is used to have a tissue effect locally. For example, the alpha-emitter Ra-223 dichloride is used as a treatment for symptomatic osseous metastases and is not typically imaged.
The radioactivity of radiopharmaceuticals are commonly measured by using miliCurie (mCi) and megaBecquerel (MBq) where 1mCi is equivalent to 37MBq 1.
Properties of an ideal diagnostic radiopharmaceutical:
short physical half life time
eliminated from the body with an effective half life time approximately equalling the examination time to prevent subsequent exposure to the body
pure gamma emitter by isomeric transition
gamma rays emitted should be monoenergetic (~150KeV)
high specific activity
localise largely and quickly at the target site
decay into a more stable daughter nucleus
easily and effectively attached to the chemical compound at room temperature
cheaplow cost per patient dosecan be easily produced or
keptstored at the hospital site
The radioactivity of radiopharmaceuticals are commonly measured by using miliCurie (mCi) and megaBecquerel (MBq) where 1mCi is equivalent to 37MBq 1.
-<p><strong>Radiopharmaceuticals</strong> are drugs that are bound to radioactive substances. The pharmaceutically active portion determines the activity that will be measured and the radioactive portion emits radiation that can be measured by the scanner.</p><p>A number of radiopharmaceuticals are used in human imaging. They share the physical characteristic of emitting radiation of various kinds. In some cases the emitted particles are detected either directly or indirectly by specialised equipment (e.g. <a href="/articles/single-photon-emission-computed-tomography-spect" title="SPECT">SPECT</a>, <a href="/articles/positron-emission-tomography" title="PET">PET</a>, <a href="/articles/gamma-camera">gamma camera</a>, etc.) to generate imaging. In other cases, the agent is used to have a tissue effect locally. </p><p>Properties of an ideal radiopharmaceutical:</p><ul>-<li><p>short <a href="/articles/half-life-time-1">physical half life time</a></p></li>-<li><p>eliminated from the body with an <a href="/articles/half-life-time-1">effective half life time</a> approximately equalling the examination time to prevent subsequent exposure to the body</p></li>-<li><p>pure <a href="/articles/gamma-decay" title="Gamma decay">gamma emitter</a> by <a href="/articles/isometric-transition">isomeric transition</a></p></li>-<li><p><a href="/articles/gamma-rays">gamma rays</a> emitted should be monoenergetic (~150KeV)</p></li>-<li><p>high <a href="/articles/specific-activity">specific activity</a></p></li>-<li><p>localise largely and quickly at the target site</p></li>-<li><p>decay into a more stable daughter nucleus</p></li>-<li><p>easily and effectively attached to the chemical compound at room temperature</p></li>-<li><p>cheap per patient dose</p></li>-<li><p>can be easily produced or kept at the hospital site</p></li>-</ul><p>The radioactivity of radiopharmaceuticals are commonly measured by using miliCurie (mCi) and megaBecquerel (MBq) where 1mCi is equivalent to 37MBq <sup>1</sup>.</p>- +<p><strong>Radiopharmaceuticals</strong> are drugs that are bound to radioactive substances. They may be used for diagnostic imaging, as therapeutic agents, or both (<a href="/articles/theranostics" title="Theranostics">theranostic</a>).</p><p>In some cases, such as <a href="/articles/iodine-123" title="Iodine-123">Iodine-123</a>, the radioactive molecule itself has a physiologic distribution that allows it to image the target organ. In others, the radioactive portion of the molecule is used primarily to tag and provide an imaging method for the pharmaceutically-active portion, which changes the biological distribution. One example of this is <a href="/articles/mibg" title="MIBG">I-123 MIBG</a>.</p><p>The particles emitted from diagnostic radiopharmaceuticals are detected either directly or indirectly by specialised equipment (e.g. <a href="/articles/single-photon-emission-computed-tomography-spect" title="SPECT">SPECT</a>, <a href="/articles/positron-emission-tomography" title="PET">PET</a>, <a href="/articles/gamma-camera">gamma camera</a>, etc.) to generate imaging. In other cases, the agent is used to have a tissue effect locally. For example, the alpha-emitter <a href="/articles/radium-223-dichloride" title="Ra-223 dichloride">Ra-223 dichloride</a> is used as a treatment for symptomatic osseous metastases and is not typically imaged.</p><p>The radioactivity of radiopharmaceuticals are commonly measured by using miliCurie (mCi) and megaBecquerel (MBq) where 1mCi is equivalent to 37MBq <sup>1</sup>.</p><h4>Properties of an ideal diagnostic radiopharmaceutical</h4><ul>
- +<li><p>short <a href="/articles/half-life-time-1">physical half life time</a></p></li>
- +<li><p>eliminated from the body with an <a href="/articles/half-life-time-1">effective half life time</a> approximately equalling the examination time to prevent subsequent exposure to the body</p></li>
- +<li><p>pure <a href="/articles/gamma-decay" title="Gamma decay">gamma emitter</a> by <a href="/articles/isometric-transition">isomeric transition</a></p></li>
- +<li><p><a href="/articles/gamma-rays">gamma rays</a> emitted should be monoenergetic (~150KeV)</p></li>
- +<li><p>high <a href="/articles/specific-activity">specific activity</a></p></li>
- +<li><p>localise largely and quickly at the target site</p></li>
- +<li><p>decay into a more stable daughter nucleus</p></li>
- +<li><p>easily and effectively attached to the chemical compound at room temperature</p></li>
- +<li><p>low cost per patient dose</p></li>
- +<li><p>can be easily produced or stored at the hospital site</p></li>
- +</ul><p></p>
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