Personalized Cancer Treatment: A futuristic illustration representing individualized radiation therapy.

Theranostics: Is Personalized Radiation Dosage the Future of Cancer Treatment?

Lena Kashyap in Health & Wellness November 2025 • 4 min read.

"Balancing Act: Weighing the benefits and challenges of individualized dosimetry in theranostic applications for cancer."

For decades, cancer treatment has often followed a one-size-fits-all approach, but now a new approach called theranostics is emerging that uses imaging to plan radiation therapy. In nuclear medicine, this means using special tracers to predict how much radiation a tumor will absorb, improving safety and ensuring the treatment is effective.

The appeal is undeniable: personalized cancer treatment. By understanding exactly how a patient's body and tumor respond to radiation, doctors can fine-tune dosages, maximizing the chances of success while minimizing harm to healthy tissues. This method hinges on internal dosimetry, which calculates the absorbed radiation doses from radiopharmaceuticals. This review explores the potential of dosimetry and the dose-response relationships of several theranostic compounds, with a focus on radioiodine therapy for differentiated thyroid cancer and peptide receptor radionuclide therapy (PRRT).

However, the path to personalized radiation therapy isn't without its bumps. Is individualized dosimetry truly necessary, just a 'nice-to-have,' or could it even be counterproductive in certain scenarios? This article will explore the advantages and challenges of using theranostics to personalize cancer treatment, and address key questions about its implementation.

The Science of Personalized Radiation: How Does Dosimetry Work?

Personalized Cancer Treatment: A futuristic illustration representing individualized radiation therapy.

Internal dosimetry is the method used for calculating radiation doses. The Medical Internal Radiation Dose (MIRD) committee developed the methodology. The approach involves several crucial steps, starting with quantitative imaging. This imaging assesses how a radiopharmaceutical moves through the body over time. Doctors use SPECT/CT or PET/CT scans to track the activity in different organs, ensuring accuracy through careful calibration and camera adjustments.

Here are key parameters involved:

D(r): represents the absorbed dose in the target region.
A(rs): represents the time-integrated activity in the source region.
S(r₁rs): is the absorbed dose rate per unit of activity in the target region from the source region (S value).

The information gathered from these scans is used to create a time-activity curve for organs and lesions, which helps calculate the total number of radioactive decays. The S value accounts for the energy released during decay and the geometry of the source and target organs. Advanced tools like voxel-based S values and software such as NUKDOS allow for patient-specific dose calculations.

The Future of Cancer Treatment: Overcoming Challenges and Embracing Personalization

Personalized radiation therapy using theranostics holds immense promise for improving cancer treatment outcomes. By carefully measuring radiation doses and considering individual patient factors, doctors can tailor treatments to maximize effectiveness and minimize side effects. Examples include monitoring 124I for thyroid cancer and assessing kidney toxicity thresholds in PRRT.

However, challenges remain. There's a need for better standardization in quantitative imaging across different centers and the creation of patient-specific S values. Harmonizing therapy protocols and dosimetry methods, as initiatives such as the MRTDOSIMETRY project aim to do, is also crucial.

Ultimately, the benefits of individualized dosimetry outweigh the challenges. With continued research and refinement, personalized radiation therapy promises to become a cornerstone of cancer treatment, offering hope for more effective and less toxic outcomes.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.2967/jnumed.116.186841, Alternate LINK

Title: Individualized Dosimetry For Theranostics: Necessary, Nice To Have, Or Counterproductive?

Subject: Radiology, Nuclear Medicine and imaging

Journal: Journal of Nuclear Medicine

Publisher: Society of Nuclear Medicine

Authors: Uta Eberlein, Marta Cremonesi, Michael Lassmann

Published: 2017-09-01

Everything You Need To Know

What exactly is theranostics, and how does it work?

Theranostics is a modern approach to cancer treatment that combines diagnostics and therapy. It utilizes imaging techniques to predict how much radiation a tumor will absorb, which allows doctors to personalize radiation therapy by tailoring dosages to each patient's specific needs. This is particularly significant because it moves away from the traditional one-size-fits-all approach, offering the potential for more effective treatments with fewer side effects.

What is individualized dosimetry and why is it important?

Individualized dosimetry is a critical aspect of theranostics, involving the calculation of absorbed radiation doses from radiopharmaceuticals. It is important because it enables the precise measurement of radiation exposure within the body. The Medical Internal Radiation Dose (MIRD) committee's methodology is used. Key parameters such as D(r), A(rs), and S(r₁rs) are used in conjunction with imaging data to create time-activity curves. These curves help doctors calculate the total number of radioactive decays. This meticulous approach helps to maximize treatment effectiveness while minimizing harm to healthy tissues, thereby ensuring personalized and safer cancer treatment.

How are SPECT/CT and PET/CT scans used in theranostics?

SPECT/CT and PET/CT scans are used in theranostics to track the movement of radiopharmaceuticals through the body. These scans provide quantitative imaging data, which is essential for internal dosimetry. Doctors use these scans to observe how a radiopharmaceutical is distributed over time, enabling the creation of time-activity curves for different organs and lesions. The accuracy of these scans relies on careful calibration and camera adjustments. These scans are essential for the precise calculations needed to personalize radiation dosages, improving safety and efficacy in cancer treatment.

What are the key parameters involved in internal dosimetry?

The key parameters in internal dosimetry include D(r), A(rs), and S(r₁rs). D(r) represents the absorbed dose in the target region. A(rs) represents the time-integrated activity in the source region. S(r₁rs) is the absorbed dose rate per unit of activity in the target region from the source region (S value). These parameters are crucial for calculating the total radiation dose a patient receives. They are used in conjunction with imaging data and patient-specific factors. Advanced tools, like voxel-based S values and software like NUKDOS, enhance the precision and personalization of dose calculations. This comprehensive approach helps to refine cancer treatment.

What is the future of personalized radiation therapy using theranostics?

The future of personalized radiation therapy using theranostics is promising. It offers the potential to greatly improve cancer treatment outcomes by allowing doctors to tailor treatments based on individual patient needs. By using methods like monitoring 124I for thyroid cancer and assessing kidney toxicity thresholds in PRRT, doctors can fine-tune dosages. This helps maximize effectiveness while minimizing side effects. Overcoming challenges associated with implementation, such as the need for advanced imaging and precise calculations, is key to unlocking the full potential of this approach. It represents a shift towards more effective and safer cancer treatment.