Skip to main content

Main menu

  • Home
  • Content
    • Current
      • JNMT Supplement
    • Ahead of print
    • Past Issues
    • Continuing Education
    • JNMT Podcast
    • SNMMI Annual Meeting Abstracts
  • Subscriptions
    • Subscribers
    • Rates
    • Journal Claims
    • Institutional and Non-member
  • Authors
    • Submit to JNMT
    • Information for Authors
    • Assignment of Copyright
    • AQARA Requirements
  • Info
    • Reviewers
    • Permissions
    • Advertisers
    • Corporate & Special Sales
  • About
    • About Us
    • Editorial Board
    • Contact Information
  • More
    • Alerts
    • Feedback
    • Help
    • SNMMI Journals
  • SNMMI
    • JNMT
    • JNM
    • SNMMI Journals
    • SNMMI

User menu

  • Subscribe
  • My alerts
  • Log in
  • My Cart

Search

  • Advanced search
Journal of Nuclear Medicine Technology
  • SNMMI
    • JNMT
    • JNM
    • SNMMI Journals
    • SNMMI
  • Subscribe
  • My alerts
  • Log in
  • My Cart
Journal of Nuclear Medicine Technology

Advanced Search

  • Home
  • Content
    • Current
    • Ahead of print
    • Past Issues
    • Continuing Education
    • JNMT Podcast
    • SNMMI Annual Meeting Abstracts
  • Subscriptions
    • Subscribers
    • Rates
    • Journal Claims
    • Institutional and Non-member
  • Authors
    • Submit to JNMT
    • Information for Authors
    • Assignment of Copyright
    • AQARA Requirements
  • Info
    • Reviewers
    • Permissions
    • Advertisers
    • Corporate & Special Sales
  • About
    • About Us
    • Editorial Board
    • Contact Information
  • More
    • Alerts
    • Feedback
    • Help
    • SNMMI Journals
  • Watch or Listen to JNMT Podcast
  • Visit SNMMI on Facebook
  • Join SNMMI on LinkedIn
  • Follow SNMMI on Twitter
  • Subscribe to JNMT RSS feeds
LetterLetters to the Editor

Fraction, Cycle, or a New Terminology? What Would Be Most Appropriate for Molecularly Targeted Radiotherapy with Unsealed Sources?

Sandip Basu
Journal of Nuclear Medicine Technology December 2015, 43 (4) 301; DOI: https://doi.org/10.2967/jnmt.115.164046
Sandip Basu
Radiation Medicine Centre Bhabha Atomic Research Centre Tata Memorial Hospital Annexe Building Jerbai Wadia Rd. Parel, Mumbai, Maharashtra, India 400 012 E-mail:
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: drsanb@yahoo.com
  • Article
  • Info & Metrics
  • PDF
Loading

TO THE EDITOR: Targeted radionuclide therapy with unsealed sources constitutes a unique form of therapy that encompasses the characteristics of both radiotherapy and systemic chemotherapy to a varying extent. Its administration, delivery, and localization can be viewed akin to those of a systemic pharmaceutical whereas the resultant therapeutic effect at the cellular target is primarily through the radiation dose delivered by the radiopharmaceutical. The therapeutic agent is localized at the target by a particular metabolic pathway or through cell-surface receptors—enzymes or peptides that have been probed by prior diagnostic imaging—forming the basis of theranostics, a popular term in recent years in the domain of unsealed molecularly based radionuclide therapy.

The dose schedule in chemotherapy is typically described by the term cycle (where a course consists of multiple cycles of chemotherapy with an interim rest period between cycles), whereas the individual radiotherapy doses are denoted by the term fractions. In unsealed radiopharmaceutical therapy, to emphasize the final therapeutic effect at the target (which is primarily by radiation-induced DNA damage), each individual dose was initially denoted by the term fraction. In recent years, however, cycle has been more frequently used (including in guidelines), particularly for intravenous radiopharmaceutical treatment (such as peptide receptor radionuclide therapy with 177Lu/90Y-DOTATATE), which is usually scheduled at a multiple regular intervals, each given the term one cycle (1). One can partly conceive that this trend shift is due to the apparent similarity between the newer intravenous therapies and systemic chemotherapies, including the issues encountered and their management. Truly, current therapies such as peptide receptor radionuclide therapy have a substantial similarity to chemotherapy schedules (including complete and efficient management of associated complications such as emesis and others both during therapy and afterward, which demands that the attending nuclear medicine physician have sound medical knowledge). In day-to-day practice, however, both fraction and cycle are frequently used interchangeably.

Another perspective is the concept of dose fractionation. Dose fractionation schedules continue to evolve in systemic radionuclide therapy and, compared with external radiotherapy, are relatively less well defined at present; among many factors, the schedule is likely to be governed by the effect achieved, the intent of therapy (neoadjuvant vs. palliative), and the biology of the tumor in question (2). Interestingly, when fractionation is based on these characteristics, the fractionated doses are at times referred to as cycles administered to the patient.

With the progression of theranostics and radionuclide therapies and the introduction of several novel unsealed systemic therapeutic agents (including the introduction of α-emitting radiopharmaceuticals) into the clinical domain, the potential of this form of therapy is likely to expand rapidly in coming years. Hence, understanding the complexities of dosimetry-related radiobiology and appropriating the associated terminology for dose schedule is a need of the hour and ought to be considered by the nuclear medicine fraternity.

Footnotes

  • Published online Sep. 3, 2015.

REFERENCES

  1. 1.↵
    1. Bodei L,
    2. Mueller-Brand J,
    3. Baum RP,
    4. et al
    . The joint IAEA, EANM, and SNMMI practical guidance on peptide receptor radionuclide therapy (PRRNT) in neuroendocrine tumours. Eur J Nucl Med Mol Imaging. 2013;40:800–816.
    OpenUrlCrossRefPubMed
  2. 2.↵
    1. Basu S
    . Dose fractionation in 131I-metaiodobenzylguanidine (MIBG) therapy: should the tumour biology and intent of therapy be the guide? Eur J Nucl Med Mol Imaging. 2010;37:1798–1799.
    OpenUrlCrossRefPubMed
PreviousNext
Back to top

In this issue

Journal of Nuclear Medicine Technology: 43 (4)
Journal of Nuclear Medicine Technology
Vol. 43, Issue 4
December 1, 2015
  • Table of Contents
  • About the Cover
  • Index by author
Print
Download PDF
Article Alerts
Sign In to Email Alerts with your Email Address
Email Article

Thank you for your interest in spreading the word on Journal of Nuclear Medicine Technology.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Fraction, Cycle, or a New Terminology? What Would Be Most Appropriate for Molecularly Targeted Radiotherapy with Unsealed Sources?
(Your Name) has sent you a message from Journal of Nuclear Medicine Technology
(Your Name) thought you would like to see the Journal of Nuclear Medicine Technology web site.
Citation Tools
Fraction, Cycle, or a New Terminology? What Would Be Most Appropriate for Molecularly Targeted Radiotherapy with Unsealed Sources?
Sandip Basu
Journal of Nuclear Medicine Technology Dec 2015, 43 (4) 301; DOI: 10.2967/jnmt.115.164046

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Share
Fraction, Cycle, or a New Terminology? What Would Be Most Appropriate for Molecularly Targeted Radiotherapy with Unsealed Sources?
Sandip Basu
Journal of Nuclear Medicine Technology Dec 2015, 43 (4) 301; DOI: 10.2967/jnmt.115.164046
Twitter logo Facebook logo LinkedIn logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One
Bookmark this article

Jump to section

  • Article
    • Footnotes
    • REFERENCES
  • Info & Metrics
  • PDF

Related Articles

  • No related articles found.
  • PubMed
  • Google Scholar

Cited By...

  • No citing articles found.
  • Google Scholar

More in this TOC Section

  • Lung Ventilation: Technegas
  • Reply to “SPECT Views for Cardiac Amyloidosis Imaging”
  • SPECT Views for Cardiac Amyloidosis Imaging
Show more Letters to the Editor

Similar Articles

SNMMI

© 2025 SNMMI

Powered by HighWire