{"id":539,"date":"2025-10-22T14:53:07","date_gmt":"2025-10-22T11:53:07","guid":{"rendered":"http:\/\/hilalbikirli.com\/why-is-the-effective-dose-still-the-most-critical-parameter-in-nuclear-medicine\/"},"modified":"2025-12-23T14:08:36","modified_gmt":"2025-12-23T11:08:36","slug":"why-is-the-effective-dose-still-the-most-critical-parameter-in-nuclear-medicine","status":"publish","type":"post","link":"https:\/\/hilalbikirli.com\/en\/why-is-the-effective-dose-still-the-most-critical-parameter-in-nuclear-medicine\/","title":{"rendered":"Why is the Effective Dose Still the Most Critical Parameter in Nuclear Medicine?"},"content":{"rendered":"\n<p><\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Nu\u0308kleer T\u0131pta Etkin Doz Neden Ha\u0302la\u0302 En Kritik Parametre?\" width=\"720\" height=\"405\" src=\"https:\/\/www.youtube.com\/embed\/ktezs8eAvok?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Effective Dose: Not Just a Number, but a Vital Indicator<\/h2>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><em>The content shared here is a summary of the article, for the full article: <a href=\"https:\/\/journals.lww.com\/health-physics\/abstract\/9900\/effective_dose_estimation_with_idac_and_olinda_for.278.aspx\" target=\"_blank\" rel=\"noreferrer noopener\">visit health physics<\/a><\/em><\/p>\n<\/blockquote>\n\n\n\n<p>Effective dose is a conceptual measure that evaluates the biological effect of ionizing radiation on the human body.<br>Simply put, this value <strong>refers to which organ is exposed to how much radiation<\/strong> and how this energy <strong>is reflected in the risk of developing cancer<\/strong> .<\/p>\n\n\n\n<p>The International Commission on Radiation Protection (<strong>ICRP<\/strong>) determines the <strong>tissue weighting factors<\/strong> used in these calculations.<br>For example, organs such as the lungs, bone marrow or thyroid are considered more sensitive to radiation; The contribution of tissues such as skin or muscle is lower.<\/p>\n\n\n\n<p>For a nuclear medicine specialist, the importance of the effective dose is twofold:<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li>To show whether the total amount of radiation received by the patient is within safe limits,<\/li>\n\n\n\n<li>To compare the dose efficiency of different imaging protocols.<\/li>\n<\/ol>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>For this reason, &#8220;effective dose&#8221; is still used as the main criterion <strong>of radiation safety policies<\/strong> today.<\/p>\n<\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\">The Role of Radiopharmaceuticals: An Anatomical Map of Internal Radiation<\/h2>\n\n\n\n<p>The most special aspect of nuclear medicine is that the radiation comes from inside the body.<br>A <strong>radiopharmaceutical<\/strong> is injected into the patient and follows different biokinetic pathways according to its involvement in organs.<\/p>\n\n\n\n<p>The two key substances used in this process \u2014 <strong>18F-FDG<\/strong> (glucose tracer) and <strong>68Ga-PSMA (prostate-specific<\/strong> membrane antigen) \u2014 accumulate in different organs throughout the body.<br>While 18F-FDG releases high energy, especially in the heart and bladder wall, it has been determined that 68Ga-PSMA is mostly retained in the kidneys.<\/p>\n\n\n\n<p>According to the results of the research:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The mean total effective dose \u2248 in <strong>18F-FDG PET\/CT<\/strong> scans was <strong>25.3 mSv<\/strong>,<\/li>\n\n\n\n<li><strong>In 68Ga-PSMA PET\/CT<\/strong> scans, the \u2248 was calculated as <strong>22.0 mSv<\/strong> .<\/li>\n<\/ul>\n\n\n\n<p>These values indicate that the CT portion contributes much more to the dose than the PET component \u2014 the <strong>CT contribution is 75% in 18F-FDG and 92% in 68Ga-PSMA<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The Difference Between the Software: IDAC-Dose 2.1 vs. OLINDA<\/h2>\n\n\n\n<p>So why do different results occur when the data of the same patient is used?<br>The answer to this is hidden in the software&#8217;s <strong>approach to biokinetic modeling<\/strong> and <strong>phantom geometry<\/strong> .<\/p>\n\n\n\n<p><strong>OLINDA\/EXM<\/strong> is built on the <strong>MIRD methodology<\/strong> that has been used since the 1980s.<br>This system uses simplified geometric representations of the human body, called <strong>&#8220;mathematical (stylized) phantoms<\/strong>&#8220;.<br>Therefore, energy transfer between organs is estimated by a more general approach.<\/p>\n\n\n\n<p>In contrast, <strong>IDAC-Dose 2.1<\/strong> uses <strong>the voxel phantom models<\/strong> developed by <strong>ICRP 110<\/strong> \u2014 i.e., <strong>three-dimensional anatomical models created from real human CT data<\/strong>.<br>This approach represents organ volumes and tissue transitions much more accurately.<\/p>\n\n\n\n<p>As a result, the PET\/CT data of the same patient produced quite different effective dose results in the two software.<br>The following table summarizes these differences  <\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Comparison of IDAC-Dose 2.1 and OLINDA\/EXM Software<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Feature \/ Parameter<\/th><th><strong>OLINDA\/EXM<\/strong><\/th><th><strong>IDAC-Dose 2.1<\/strong><\/th><\/tr><\/thead><tbody><tr><td><strong>Basic Methodology<\/strong><\/td><td>MIRD (Medical Internal Radiation Dose)<\/td><td>Advanced modeling based on ICRP 128 and 110 guidelines<\/td><\/tr><tr><td><strong>Phantom Type<\/strong><\/td><td><em>Stylized phantom<\/em><\/td><td><em>Voxel (3D real human anatomy)<\/em> phantom<\/td><\/tr><tr><td><strong>Data Source<\/strong><\/td><td>Standard reference values (ICRP 60, 1990)<\/td><td>Real CT data (ICRP 103, 2007)<\/td><\/tr><tr><td><strong>Tissue Weight Factor<\/strong><\/td><td>ICRP 60<\/td><td>ICRP 103<\/td><\/tr><tr><td><strong>Radiopharmaceutical Modeling<\/strong><\/td><td>Simplified biokinetic data<\/td><td>Updated biokinetic dataset<\/td><\/tr><tr><td><strong>Effective Dose (18F-FDG, PET)<\/strong><\/td><td><strong>9.96 mSv<\/strong><\/td><td><strong>6.28 mSv<\/strong><\/td><\/tr><tr><td><strong>Proximity to Clinical Reality<\/strong><\/td><td>Intermediate \u2013 estimated<\/td><td>High \u2013 individualized modeling<\/td><\/tr><tr><td><strong>Advantage<\/strong><\/td><td>Easy-to-use, classic model<\/td><td>More accurate organ and tissue representation<\/td><\/tr><tr><td><strong>Disadvantage<\/strong><\/td><td>Old tissue coefficients, tendency to overdose estimation<\/td><td>More complex data entry and processing time<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>This difference clearly shows that the <strong>calculation of the effective dose<\/strong> in nuclear medicine depends not only on the <strong>amount of activity<\/strong> injected but also on <strong>the geometry of the mathematical model<\/strong> used.<\/p>\n\n\n\n<p>In other words, when the <strong>biokinetic model<\/strong> used for the same patient changes, the <strong>radiation safety assessment<\/strong> may also change.<br>Therefore, in modern clinical practice, the use of voxel-based software such as <strong>IDAC-Dose 2.1<\/strong> is now a necessity for both <strong>scientific accuracy<\/strong> and <strong>patient safety<\/strong> .<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">ICRP 60 and 103: Generational Difference in Radiation Risk<\/h2>\n\n\n\n<p>Radiation safety guidelines have also evolved over time.<br>In the ICRP 60 (1990) model, tissue weight factors were determined based on limited clinical data.<br>The newly published <strong>ICRP 103 (2007)<\/strong> standard re-evaluated organ sensitivities with long-term epidemiological studies.<\/p>\n\n\n\n<p>For example, the risk coefficient of breast and thyroid tissues is increased; the liver is reduced. These changes have enabled new software, such as IDAC-Dose 2.1, to produce <strong>lower and more realistic effective doses<\/strong> . <\/p>\n\n\n\n<p>In other words, as science has advanced, the <strong>meaning of measurement<\/strong> , not measurement, has changed. This, in turn, helps protect patients from unnecessary high-risk predictions. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Clinical Reality: 90% of the Effective Dose Originates from CT<\/h2>\n\n\n\n<p>One of the most striking findings in the study is <strong>the predominance of CT&#8217;s contribution to the total effective dose<\/strong>.<br>In other words, the patient receives more radiation due to the X-rays he is exposed to in the <strong>tomography (CT)<\/strong> part than the radiopharmaceutical used for PET.<\/p>\n\n\n\n<p>In the study, the average CT effective doses were calculated as follows:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>18F-FDG protocol:<\/strong> 19.05 \u00b1 5.89 mSv<\/li>\n\n\n\n<li><strong>68Ga-PSMA protocol:<\/strong> 20.17 \u00b1 5.87 mSv<\/li>\n<\/ul>\n\n\n\n<p>These differences highlight the importance of low-dose CT protocols.<br>Modern hospitals now use <strong>dose monitoring systems<\/strong> to instantly monitor the total radiation received by each patient. The goal is simple: <strong>to adhere to the principle of &#8220;lowest reasonably achievable dose&#8221; (ALARA).<\/strong> <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The Human Side of the Story: Through the Eyes of an Expert<\/h2>\n\n\n\n<p>For a nuclear medicine specialist, an &#8220;effective dose&#8221; is not just a statistic; It is a decision that he makes hundreds of times in each scan.<br>When a patient enters the PET\/CT device, the physician has to rely on the software in hand.<br>If the calculation model is outdated, the patient may receive more radiation than necessary \u2014 or the tumor may be misjudged.<br>The goal is to achieve &#8220;individualized dose optimization&#8221; tailored to each patient.<\/p>\n\n\n\n<p>In the near future, these calculations are expected to be automated <strong>with artificial intelligence-supported systems<\/strong> .<br>Machine learning algorithms have the potential to perform instant <strong>radiopharmaceutical dose optimization<\/strong> based on patient age, gender, metabolic activity and organ volumes.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Looking to the Future: Between Science, Ethics, and Technology<\/h2>\n\n\n\n<p>The reason why the effective dose is still the most critical parameter in nuclear medicine is that it carries <strong>both a scientific and ethical responsibility<\/strong> .<br>More than every millisievert, it&#8217;s about the safety of a patient.<\/p>\n\n\n\n<p>The PET\/CT technologies of the future promise not only higher resolution images, but also <strong>systems that operate with lower risk<\/strong> .<br><strong>Dose planning software<\/strong> integrated with artificial intelligence will be able to analyze individual biokinetic data based on the ICRP 103 guideline. <\/p>\n\n\n\n<p>After all, the power of unseen light will no longer be used not only for diagnosis, but also <strong>to protect human health<\/strong> .<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>So, do you think the nuclear medicine of the future will be able to achieve a &#8220;zero risk&#8221; imaging protocol specific to each patient?<\/p>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>Effective Dose: Not Just a Number, but a Vital Indicator The content shared here is a summary of the article, for the full article: visit health physics Effective dose is a conceptual measure that evaluates the biological effect of ionizing radiation on the human body.Simply put, this value refers to which organ is exposed to&#8230;<\/p>\n","protected":false},"author":1,"featured_media":540,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":"","beyondwords_generate_audio":"","beyondwords_integration_method":"","beyondwords_project_id":"","beyondwords_content_id":"","beyondwords_preview_token":"","beyondwords_player_content":"","beyondwords_player_style":"","beyondwords_language_code":"","beyondwords_language_id":"","beyondwords_title_voice_id":"","beyondwords_body_voice_id":"","beyondwords_summary_voice_id":"","beyondwords_error_message":"","beyondwords_disabled":"","beyondwords_delete_content":"","beyondwords_podcast_id":"","beyondwords_hash":"","publish_post_to_speechkit":"","speechkit_hash":"","speechkit_generate_audio":"","speechkit_project_id":"","speechkit_podcast_id":"","speechkit_error_message":"","speechkit_disabled":"","speechkit_access_key":"","speechkit_error":"","speechkit_info":"","speechkit_response":"","speechkit_retries":"","speechkit_status":"","speechkit_updated_at":"","_speechkit_link":"","_speechkit_text":""},"categories":[38],"tags":[],"class_list":["post-539","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-general"],"taxonomy_info":{"category":[{"value":38,"label":"General"}]},"featured_image_src_large":["https:\/\/hilalbikirli.com\/wp-content\/uploads\/2025\/10\/SaLEGGKWzU8x3ne_DG38g-1024x614.png",1024,614,true],"author_info":{"display_name":"Hilal Bikirli","author_link":"https:\/\/hilalbikirli.com\/en\/author\/hilalbikirli\/"},"comment_info":0,"category_info":[{"term_id":38,"name":"General","slug":"general","term_group":0,"term_taxonomy_id":38,"taxonomy":"category","description":"","parent":0,"count":3,"filter":"raw","cat_ID":38,"category_count":3,"category_description":"","cat_name":"General","category_nicename":"general","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/posts\/539","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/comments?post=539"}],"version-history":[{"count":2,"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/posts\/539\/revisions"}],"predecessor-version":[{"id":1076,"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/posts\/539\/revisions\/1076"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/media\/540"}],"wp:attachment":[{"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/media?parent=539"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/categories?post=539"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hilalbikirli.com\/en\/wp-json\/wp\/v2\/tags?post=539"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}