Gallium scan

File:Gallium 67 Scan (Diagnosis of Sarcoidosis).png in the absence of histological confirmation]]

In the past, the gallium scan was the gold standard for lymphoma staging, until it was replaced by positron emission tomography (PET) using ¹⁸F-fluorodeoxyglucose (FDG).{{cite book|last1=Bryan|first1=R Nick|title=Introduction to the science of medical imaging|date=2010|publisher=Cambridge University Press|location=Cambridge|isbn=9780521747622|page=200|url=https://books.google.com/books?id=wzn5Voq-hH4C&pg=PA200|access-date=20 February 2017|archive-date=21 February 2017|archive-url=https://web.archive.org/web/20170221112237/https://books.google.com/books?id=wzn5Voq-hH4C&pg=PA200|url-status=live}}{{cite journal|last1=Bleeker-Rovers|first1=C. P.|last2=Vos|first2=F. J.|last3=van der Graaf|first3=W. T. A.|last4=Oyen|first4=W. J. G.|title=Nuclear Medicine Imaging of Infection in Cancer Patients (With Emphasis on FDG-PET)|journal=The Oncologist|date=16 June 2011|volume=16|issue=7|pages=980–991|doi=10.1634/theoncologist.2010-0421|pmc=3228133|pmid=21680576}} ⁶⁷Ga-citrate imaging is still used to image inflammation and chronic infections, and it still sometimes locates unsuspected tumors as it is taken up by many kinds of cancer cells in amounts that exceed those of normal tissues. Thus, an increased uptake of gallium-67 may indicate a new or old infection, an inflammatory focus from any cause, or a cancerous tumor.

It has been suggested that gallium imaging may become an obsolete technique, with indium leukocyte imaging and technetium antigranulocyte antibodies replacing it as a detection mechanism for infections. For detection of tumors, especially lymphomas, gallium-67 imaging is still in use, but may be completely replaced by Fluorodeoxyglucose18F-fluorodeoxyglucose PET imaging in the future.{{cite book|last1=Ziessman|first1=Harvey A.|last2=O'Malley|first2=Janis P.|last3=Thrall|first3=James H.|title=Nuclear Medicine: The Requisites E-Book|date=2013|publisher=Elsevier Health Sciences|isbn=978-0323112925|page=281|url=https://books.google.com/books?id=vtbiyAfP3X4C&pg=PA281|language=en}}

In infections, the gallium scan has an advantage over indium leukocyte imaging in imaging osteomyelitis (bone infection) of the spine, lung infections and inflammation, and for chronic infections. In part this is because gallium binds to neutrophil membranes, even after neutrophil death. Indium leukocyte imaging is better for acute infections (where neutrophils are still rapidly and actively localizing to the infection), and also for osteomyelitis that does not involve the spine, and for abdominal and pelvic infections. Both the gallium scan and indium leukocyte imaging may be used to image fever of unknown origin (elevated temperature without an explanation). However, the indium leukocyte scan will image only the 25% of such cases which are caused by acute infections, while gallium will also localize to other sources of fever, such as chronic infections and tumors.{{cite journal|last1=Palestro|first1=Christopher J.|title=The current role of gallium imaging in infection|journal=Seminars in Nuclear Medicine|date=April 1994|volume=24|issue=2|pages=128–141|doi=10.1016/S0001-2998(05)80227-2|pmid=8023169}}{{cite book|last1=Shields|first1=Thomas W.|last2=LoCicero|first2=Joseph|last3=Reed|first3=Carolyn E.|last4=Feins|first4=Richard H.|title=General Thoracic Surgery|date=2009|publisher=Lippincott Williams & Wilkins|isbn=9780781779821|page=2106|url=https://books.google.com/books?id=bVEEHmpU-1wC&pg=PA2106|language=en}}

The body generally handles Ga³⁺ as though it were ferric iron (Fe-III), and thus the free isotope ion is bound (and concentrates) in areas of inflammation, such as an infection site, and also areas of rapid cell division.{{cite journal|last1=Love|first1=C|last2=Palestro|first2=CJ|title=Radionuclide imaging of infection.|journal=Journal of Nuclear Medicine Technology|date=June 2004|volume=32|issue=2|pages=47–57; quiz 58–9|pmid=15175400|url=http://tech.snmjournals.org/content/32/2/47.long|access-date=20 February 2017|archive-date=7 November 2016|archive-url=https://web.archive.org/web/20161107211734/http://tech.snmjournals.org/content/32/2/47.long|url-status=live}} Gallium (III) (Ga³⁺) binds to transferrin, leukocyte lactoferrin, bacterial siderophores, inflammatory proteins, and cell-membranes in neutrophils, both living and dead.{{cite journal|last1=Tsan|first1=MF|title=Mechanism of gallium-67 accumulation in inflammatory lesions.|journal=Journal of Nuclear Medicine|date=January 1985|volume=26|issue=1|pages=88–92|pmid=3880816}}

Lactoferrin is contained within leukocytes. Gallium may bind to lactoferrin and be transported to sites of inflammation, or binds to lactoferrin released during bacterial phagocytosis at infection sites (and remains due to binding with macrophage receptors).{{cite book|last1=Greenberg|first1=Alex M|last2=Prein|first2=Joachim|title=Craniomaxillofacial reconstructive and corrective bone surgery principles of internal fixation using AO/ASIF technique|date=2007|publisher=Springer|location=New York|isbn=9780387224275|page=79}} Gallium-67 also attaches to the siderophore molecules of bacteria themselves, and for this reason can be used in leukopenic patients with bacterial infection (here it attaches directly to bacterial proteins, and leukocytes are not needed).{{cite journal|last1=Weiner|first1=R.E.|title=The mechanism of 67Ga localization in malignant disease|journal=Nuclear Medicine and Biology|date=1996|volume=23|issue=6|pages=745–751|doi=10.1016/0969-8051(96)00119-9|pmid=8940716}} Uptake is thought to be associated with a range of tumour properties including transferring receptors, anaerobic tumor metabolism and tumor perfusion and vascular permeability.{{cite book|last1=Biersack|first1=Hans-Jürgen|last2=Freeman|first2=Leonard M|title=Clinical nuclear medicine|date=2007|publisher=Springer|location=Berlin|isbn=978-3-540-28026-2|page=324}}{{cite journal|last1=Hoffer|first1=P|title=Gallium: mechanisms|journal=Journal of Nuclear Medicine|date=1980|volume=21|issue=3|pages=282–5|pmid=6988551|url=http://jnm.snmjournals.org/content/21/3/282|access-date=20 February 2017|archive-date=7 July 2022|archive-url=https://web.archive.org/web/20220707044051/https://jnm.snmjournals.org/content/21/3/282|url-status=live}}

• Whole-body survey to localize source of fever in patients with fever of unknown origin.{{cite web|title=Gallium scan|url=https://medlineplus.gov/ency/article/003450.htm|website=MedlinePlus|access-date=14 September 2017|language=en|archive-date=14 September 2017|archive-url=https://web.archive.org/web/20170914173104/https://medlineplus.gov/ency/article/003450.htm|url-status=live}}
• Detection of pulmonary and mediastinal inflammation/infection, especially in the immunocompromised patient.{{cite web|title=ACR–SPR Practice Parameter for the Performance of Scintigraphy for Inflammation and Infection|url=https://www.acr.org/~/media/ACR/Documents/PGTS/guidelines/Infections_Inflammation.pdf|website=American College of Radiology|date=2014|access-date=14 September 2017|archive-date=16 October 2015|archive-url=https://web.archive.org/web/20151016184931/http://www.acr.org/~/media/ACR/Documents/PGTS/guidelines/Infections_Inflammation.pdf}}
• Evaluation and follow-up of active lymphocytic or granulomatous inflammatory processes such as sarcoidosis or tuberculosis.{{cite web|title=Lung gallium scan|url=https://medlineplus.gov/ency/article/003824.htm|website=MedlinePlus|access-date=14 September 2017|language=en|archive-date=14 September 2017|archive-url=https://web.archive.org/web/20170914172629/https://medlineplus.gov/ency/article/003824.htm|url-status=live}}
• Diagnosing vertebral osteomyelitis and/or disk space infection where gallium-67 is preferred over labeled leukocytes.
• Diagnosis and follow-up of medical treatment of retroperitoneal fibrosis.
• Evaluation and follow-up of drug-induced pulmonary toxicity (e.g. Bleomycin, Amiodarone)
• Evaluation of patients who are not candidates for WBC scans (WBC count less than 6,000).

Note that all of these conditions are also seen in PET scans using the gallium-68.

The main (⁶⁷Ga) technique uses scintigraphy to produce two-dimensional images. After the tracer has been injected, images are typically taken by a gamma camera at 24, 48, and in some cases, 72, and 96 hours later.{{cite web|last1=Bombardieri|first1=Emilio|last2=Aktolun|first2=Cumali|last3=Baum|first3=Richard P.|last4=Bishof-Delaloye|first4=Angelica|last5=Buscombe|first5=John|last6=Chatal|first6=Jean François|last7=Maffioli|first7=Lorenzo|last8=Moncayo|first8=Roy|last9=Mortelmans|first9=Luc|last10=Reske|first10=Sven N.|title=⁶⁷Ga Scintigraphy Procedure Guidelines for Tumour Imaging|url=http://www.eanm.org/publications/guidelines/gl_onco_gascin.pdf|website=EANM|date=2 September 2003|access-date=14 September 2017|archive-date=26 October 2020|archive-url=https://web.archive.org/web/20201026051436/https://www.eanm.org/publications/guidelines/gl_onco_gascin.pdf|url-status=live}}{{cite web|title=Society of Nuclear Medicine Procedure Guideline for Gallium Scintigraphy in Inflammation|url=http://snmmi.files.cms-plus.com/docs/Gallium_Scintigraphy_in_Inflammation_v3.pdf|website=SNMMI|date=2 June 2004|access-date=7 September 2016|archive-date=21 October 2016|archive-url=https://web.archive.org/web/20161021014631/http://snmmi.files.cms-plus.com/docs/Gallium_Scintigraphy_in_Inflammation_v3.pdf|url-status=live}} Each set of images takes 30–60 minutes, depending on the size of the area being imaged. The resulting image will have bright areas that collected large amounts of tracer, because inflammation is present or rapid cell division is occurring. Single-photon emission computed tomography (SPECT) images may also be acquired. In some imaging centers, SPECT images may be combined with computed tomography (CT) scan using either fusion software or SPECT/CT hybrid cameras to superimpose both physiological image-information from the gallium scan, and anatomical information from the CT scan.

A common injection dose is around 150 megabecquerels.{{cite web|title=Notes for Guidance on the Clinical Administration of Radiopharmaceuticals and Use of Sealed Radioactive Sources|url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/492127/ARSAC_NfG_2016.pdf|publisher=Administration of Radioactive Substances Advisory Committee|access-date=7 September 2016|date=January 2016|archive-date=24 September 2016|archive-url=https://web.archive.org/web/20160924110022/https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/492127/ARSAC_NfG_2016.pdf|url-status=live}} Imaging should not usually be sooner than 24 hours as high background at this time produces false negatives. Forty-eight-hour whole body images are appropriate. Delayed imaging can be obtained even 1 week or longer after injection if bowel is confounding. SPECT can be performed as needed. Oral laxatives or enemas can be given before imaging to reduce bowel activity and reduce dose to large bowel; however, the usefulness of bowel preparation is controversial.

10% to 25% of the dose of gallium-67 is excreted within 24 hours after injection (the majority of which is excreted through the kidneys). After 24 hours the principal excretory pathway is colon. The "target organ" (organ that receives the largest radiation dose in the average scan) is the colon (large bowel).

In a normal scan, uptake of gallium is seen in wide range of locations which do not indicate a positive finding. These typically include soft tissues, liver, and bone. Other sites of localisation can be nasopharyngeal and lacrimal glands, breasts (particularly in lactation or pregnancy), normally healing wounds, kidneys, bladder and colon.{{cite book|last1=Palestro|first1=Christopher J.|editor1-last=Fogelman|editor1-first=Ignac|editor2-last=Gnanasegaran|editor2-first=Gopinath|editor3-last=van der Wall|editor3-first=Hans|title=Radionuclide and hybrid bone imaging|date=2012|publisher=Springer|location=Berlin|isbn=978-3-642-02399-6|pages=523–559|chapter=SPECT and PET in the Assessment of Bone Infections|doi=10.1007/978-3-642-02400-9_20}}

{{anchor|Gallium Ga 68 PSMA-11}}

{{see also|PSMA scan}}

File:Gallium PSMA PET scan.png

The positron emitting isotope, ⁶⁸Ga, can be used to target prostate-specific membrane antigen (PSMA), a protein which is present in prostate cancer cells. The technique has been shown to improve detection of metastatic disease compared to MRI or CT scans.{{cite journal|last1=Maurer|first1=Tobias|last2=Eiber|first2=Matthias|last3=Schwaiger|first3=Markus|last4=Gschwend|first4=Jürgen E.|title=Current use of PSMA–PET in prostate cancer management|journal=Nature Reviews Urology|date=23 February 2016|volume=13|issue=4|pages=226–235|doi=10.1038/nrurol.2016.26|pmid=26902337|s2cid=2448922}}

In December 2020, the U.S. Food and Drug Administration (FDA) approved ⁶⁸Ga PSMA-11 for medical use in the United States.{{cite web | title=Drug Approval Package: Gallium Ga 68 PSMA-11 | website=U.S. Food and Drug Administration (FDA) | date=16 December 2020 | url=https://www.accessdata.fda.gov/drugsatfda_docs/nda/2020/212642Orig1s000TOC.cfm | access-date=25 December 2020 | archive-date=26 January 2021 | archive-url=https://web.archive.org/web/20210126195616/https://www.accessdata.fda.gov/drugsatfda_docs/nda/2020/212642Orig1s000TOC.cfm | url-status=live }}{{cite web | title=Drug Trials Snapshot: Ga 68 PSMA-11 | website=U.S. Food and Drug Administration (FDA) | date=1 December 2020 | url=https://www.fda.gov/drugs/drug-approvals-and-databases/drug-trials-snapshot-ga-68-psma-11 | access-date=11 December 2020 | archive-date=10 December 2020 | archive-url=https://web.archive.org/web/20201210145026/https://www.fda.gov/drugs/drug-approvals-and-databases/drug-trials-snapshot-ga-68-psma-11 | url-status=live }} {{PD-notice}} It is indicated for positron emission tomography (PET) of prostate specific membrane antigen (PSMA) positive lesions in men with prostate cancer.{{cite web |title=GALLIUM GA 68 PSMA-11 Labeling-Package Insert |url=https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/212642s001lbl.pdf |website=Drugs@FDA |publisher=University of California, Los Angeles |access-date=18 March 2022 |date=17 November 2021 |archive-date=13 May 2022 |archive-url=https://web.archive.org/web/20220513002315/https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/212642s001lbl.pdf |url-status=live }} It is manufactured by the UCLA Biomedical Cyclotron Facility. The FDA approved ⁶⁸Ga PSMA-11 based on evidence from two clinical trials (Trial 1/NCT0336847 identical to NCT02919111 and Trial 2/NCT02940262 identical to NCT02918357) of male participants with prostate cancer. Some participants were recently diagnosed with the prostate cancer. Other participants were treated before, but there was suspicion that the cancer was spreading because of rising prostate specific antigen or PSA. The trials were conducted at two sites in the United States.

The FDA considers ⁶⁸Ga PSMA-11 to be a first-in-class medication.{{cite web | title=New Drug Therapy Approvals 2020 | website=U.S. Food and Drug Administration (FDA) | date=31 December 2020 | url=https://www.fda.gov/drugs/new-drugs-fda-cders-new-molecular-entities-and-new-therapeutic-biological-products/new-drug-therapy-approvals-2020 | access-date=17 January 2021 | archive-date=18 January 2021 | archive-url=https://web.archive.org/web/20210118011953/https://www.fda.gov/drugs/new-drugs-fda-cders-new-molecular-entities-and-new-therapeutic-biological-products/new-drug-therapy-approvals-2020 | url-status=live }}

Gallium PSMA scanning is recommended primarily in cases of biochemical recurrence of prostate cancer, particularly for patients with low PSA values, and in patients with high risk disease where metastases are considered likely.{{cite journal|last1=Fendler|first1=Wolfgang P.|last2=Eiber|first2=Matthias|last3=Beheshti|first3=Mohsen|last4=Bomanji|first4=Jamshed|last5=Ceci|first5=Francesco|last6=Cho|first6=Steven|last7=Giesel|first7=Frederik|last8=Haberkorn|first8=Uwe|last9=Hope|first9=Thomas A.|last10=Kopka|first10=Klaus|last11=Krause|first11=Bernd J.|last12=Mottaghy|first12=Felix M.|last13=Schöder|first13=Heiko|last14=Sunderland|first14=John|last15=Wan|first15=Simon|last16=Wester|first16=Hans-Jürgen|last17=Fanti|first17=Stefano|last18=Herrmann|first18=Ken|title=68Ga-PSMA PET/CT: Joint EANM and SNMMI procedure guideline for prostate cancer imaging: version 1.0|journal=European Journal of Nuclear Medicine and Molecular Imaging|date=10 March 2017|volume=44|issue=6|pages=1014–1024|doi=10.1007/s00259-017-3670-z|pmid=28283702|s2cid=5882407}}{{cite journal|last1=Rai|first1=Bhavan Prasad|last2=Baum|first2=Richard Paul|last3=Patel|first3=Amit|last4=Hughes|first4=Robert|last5=Alonzi|first5=Roberto|last6=Lane|first6=Tim|last7=Adshead|first7=Jim|last8=Vasdev|first8=Nikhil|title=The Role of Positron Emission Tomography With 68Gallium (Ga)-Labeled Prostate-specific Membrane Antigen (PSMA) in the Management of Patients With Organ-confined and Locally Advanced Prostate Cancer Prior to Radical Treatment and After Radical Prostatectomy|journal=Urology|date=September 2016|volume=95|pages=11–15|doi=10.1016/j.urology.2015.12.048|pmid=26790588}}

An intravenous administration of 1.8–2.2 megabecquerels of ⁶⁸Ga PSMA-11 per kilogram of bodyweight is recommended. Imaging should commence approximately 60 minutes after administration with an acquisition from mid-thigh to the base of the skull.{{cite journal|last1=Afaq|first1=Asim|last2=Batura|first2=Deepak|last3=Bomanji|first3=Jamshed|title=New frontiers in prostate cancer imaging: clinical utility of prostate-specific membrane antigen positron emission tomography|journal=International Urology and Nephrology|date=14 February 2017|volume=49|issue=5|pages=803–810|doi=10.1007/s11255-017-1541-y|pmid=28197764|s2cid=3902900}}

{{anchor|Gallium DOTA scans}}

{{anchor|Gallium-68 DOTA-TATE}}

{{anchor|Gallium-68 DOTA-TOC}}

⁶⁸Ga DOTA conjugated peptides (including ⁶⁸Ga DOTA-TATE, DOTA-TOC and DOTA-NOC) are used in positron emission tomography (PET) imaging of neuroendocrine tumours (NETs). The scan is similar to the SPECT octreotide scan in that an octreotide-based somatostatin analogue (such as edotreotide) is used as the radioligand, and there are similar indications and uses as ocreotide scans, however image quality is significantly improved.{{cite journal|last1=Mojtahedi|first1=Alireza|last2=Thamake|first2=Sanjay|last3=Tworowska|first3=Izabela|last4=Ranganathan|first4=David|last5=Delpassand|first5=Ebrahim S|title=The value of 68Ga-DOTATATE PET/CT in diagnosis and management of neuroendocrine tumors compared to current FDA approved imaging modalities: a review of literature|journal=American Journal of Nuclear Medicine and Molecular Imaging|date=15 August 2014|volume=4|issue=5|pages=426–434|issn=2160-8407|pmc=4138137|pmid=25143861}} Somatostatin receptors are overexpressed in many NETs, so that the ⁶⁸Ga DOTA conjugated peptide is preferentially taken up in these locations, and visualised on the scan.{{cite journal|last1=Virgolini|first1=Irene|last2=Ambrosini|first2=Valentina|last3=Bomanji|first3=Jamshed B.|last4=Baum|first4=Richard P.|last5=Fanti|first5=Stefano|last6=Gabriel|first6=Michael|last7=Papathanasiou|first7=Nikolaos D.|last8=Pepe|first8=Giovanna|last9=Oyen|first9=Wim|last10=De Cristoforo|first10=Clemens|last11=Chiti|first11=Arturo|title=Procedure guidelines for PET/CT tumour imaging with 68Ga-DOTA-conjugated peptides: 68Ga-DOTA-TOC, 68Ga-DOTA-NOC, 68Ga-DOTA-TATE|journal=European Journal of Nuclear Medicine and Molecular Imaging|date=2 July 2010|volume=37|issue=10|pages=2004–2010|doi=10.1007/s00259-010-1512-3|pmid=20596866|s2cid=11469889|url=http://www.eanm.org/publications/guidelines/gl_Ga68DOTA.pdf|access-date=6 October 2017|archive-date=17 May 2017|archive-url=https://web.archive.org/web/20170517071020/http://www.eanm.org/publications/guidelines/gl_Ga68DOTA.pdf|url-status=live}} As well as diagnosis and staging of NETs, ⁶⁸Ga DOTA conjugated peptide imaging may be used for planning and dosimetry in preparation for lutetium-177 or yttrium-90 DOTA therapy.{{cite journal|last1=Kam|first1=B. L. R.|last2=Teunissen|first2=J. J. M.|last3=Krenning|first3=E. P.|last4=de Herder|first4=W. W.|last5=Khan|first5=S.|last6=van Vliet|first6=E. I.|last7=Kwekkeboom|first7=D. J.|title=Lutetium-labelled peptides for therapy of neuroendocrine tumours|journal=European Journal of Nuclear Medicine and Molecular Imaging|date=3 March 2012|volume=39|issue=S1|pages=103–112|doi=10.1007/s00259-011-2039-y|pmc=3304065|pmid=22388631}}{{cite journal|last1=Taïeb|first1=David|last2=Garrigue|first2=Philippe|last3=Bardiès|first3=Manuel|last4=Abdullah|first4=Ahmad Esmaeel|last5=Pacak|first5=Karel|title=Application and Dosimetric Requirements for Gallium-68–labeled Somatostatin Analogues in Targeted Radionuclide Therapy for Gastroenteropancreatic Neuroendocrine Tumors|journal=PET Clinics|date=October 2015|volume=10|issue=4|pages=477–486|doi=10.1016/j.cpet.2015.06.001|pmc=4617555|pmid=26384594}}

In June 2016, Netspot (kit for the preparation of gallium Ga-68 dotatate injection) was approved for medical use in the United States.{{cite web | title=Netspot (kit for the preparation of gallium Ga 68 dotatate injection) | website=U.S. Food and Drug Administration (FDA) | date=21 June 2016 | url=https://www.accessdata.fda.gov/drugsatfda_docs/nda/2016/208547Orig1s000TOC.cfm | access-date=18 October 2020 | archive-date=31 March 2021 | archive-url=https://web.archive.org/web/20210331014242/https://www.accessdata.fda.gov/drugsatfda_docs/nda/2016/208547Orig1s000TOC.cfm | url-status=live }}

• {{lay source|template=cite web |date=30 May 2016 |title=Summary Review: Application number: 208547Orig1s000 |website=Center for Drug Evaluation and Research |url=https://www.accessdata.fda.gov/drugsatfda_docs/nda/2016/208547Orig1s000SumR.pdf}}{{cite web | title=Netspot- 68ga-dotatate kit | website=DailyMed | date=23 October 2019 | url=https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b2b3be70-17d8-4093-896c-f1c54a2cf242 | access-date=18 October 2020 | archive-date=22 September 2020 | archive-url=https://web.archive.org/web/20200922190132/https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b2b3be70-17d8-4093-896c-f1c54a2cf242 | url-status=live }}

In August 2019, ⁶⁸Ga edotreotide injection (⁶⁸Ga DOTATOC) was approved for medical use in the United States for use with PET imaging for the localization of somatostatin receptor positive neuroendocrine tumors (NETs) in adults and children.{{cite web | title=GA-68-DOTATOC- edotreotide gallium ga-68 injection, solution | website=DailyMed | date=3 September 2019 | url=https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c4d185c3-d520-462d-ba50-4f4ee485ace3 | access-date=17 March 2020 | archive-date=7 July 2022 | archive-url=https://web.archive.org/web/20220707044051/https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c4d185c3-d520-462d-ba50-4f4ee485ace3 | url-status=live }}{{cite web | title=Drug Trials Snapshots: Ga-68-DOTATOC | website=U.S. Food and Drug Administration (FDA) | date=21 August 2019 | url=http://www.fda.gov/drugs/drug-approvals-and-databases/drug-trials-snapshots-ga-68-dotatoc | access-date=17 March 2020 | archive-date=13 December 2019 | archive-url=https://web.archive.org/web/20191213225244/https://www.fda.gov/drugs/drug-approvals-and-databases/drug-trials-snapshots-ga-68-dotatoc | url-status=live }} {{PD-notice}}{{cite web | title=Drug Approval Package: Gallium Dotatoc GA 68 | website=U.S. Food and Drug Administration (FDA) | date=23 September 2019 | url=https://www.accessdata.fda.gov/drugsatfda_docs/nda/2019/210828Orig1s000TOC.cfm | access-date=18 October 2020 | archive-date=6 April 2021 | archive-url=https://web.archive.org/web/20210406183418/https://www.accessdata.fda.gov/drugsatfda_docs/nda/2019/210828Orig1s000TOC.cfm | url-status=live }}

The U.S. Food and Drug Administration (FDA) approved ⁶⁸Ga edotreotide (DOTATOC) based on evidence from three clinical trials (Trial 1/NCT#1619865, Trial 2/NCT#1869725, Trial 3/NCT#2441062) of 334 known or suspected neuro-endocrine tumors. The trials were conducted in the United States.

Gallium (⁶⁸Ga) oxodotreotide was approved for medical use in Canada as Netspot in July 2019,{{cite web | title=Summary Basis of Decision (SBD) for Netspot | website=Health Canada | date=23 October 2014 | url=https://hpr-rps.hres.ca/reg-content/summary-basis-decision-detailTwo.php?linkID=SBD00467&lang=en | access-date=29 May 2022 | archive-date=31 May 2022 | archive-url=https://web.archive.org/web/20220531045953/https://hpr-rps.hres.ca/reg-content/summary-basis-decision-detailTwo.php?linkID=SBD00467&lang=en | url-status=live }} and as Netvision in May 2022.{{cite web | title=Summary Basis of Decision - NETVision | website=Health Canada | date=26 May 2022 | url=https://hpr-rps.hres.ca/reg-content/summary-basis-decision-detailTwo.php?lang=en&linkID=SBD00588 | access-date=7 July 2022 | archive-date=7 July 2022 | archive-url=https://web.archive.org/web/20220707044051/https://hpr-rps.hres.ca/reg-content/summary-basis-decision-detailTwo.php?lang=en&linkID=SBD00588 | url-status=live }}

The combination germanium (68Ge) chloride / gallium (68Ga) chloride was approved for medical use in the European Union in August 2024.{{cite web | title=GalliaPharm EPAR | website=European Medicines Agency (EMA) | date=1 August 2024 | url=https://www.ema.europa.eu/en/medicines/human/EPAR/galliapharm | access-date=26 August 2024}}

Other gallium-68 based PET scanning agents may also be based on the principle of attaching peptides to chelators, such as the in-development drug Ga-68-Trivehexin.

Gallium-67 citrate is produced by a cyclotron. Charged particle bombardment of enriched Zn-68 is used to produce gallium-67. The gallium-67 is then complexed with citric acid to form gallium citrate. The half-life of gallium-67 is 78 hours.{{cite book|last1=IAEA|title=Cyclotron produced radionuclides: physical characteristics and production methods|date=2009|publisher=International Atomic Energy Agency|location=Vienna|isbn=9789201069085|page=116|url=http://www-pub.iaea.org/MTCD/publications/PDF/trs468_web.pdf|access-date=7 September 2016|archive-date=9 March 2017|archive-url=https://web.archive.org/web/20170309080624/http://www-pub.iaea.org/MTCD/Publications/PDF/trs468_web.pdf|url-status=live}} It decays by electron capture, then emits de-excitation gamma rays that are detected by a gamma camera. Primary emission is at 93 keV (39% abundance), followed by 185 keV (21%) and 300 keV (17%).{{cite book|last1=Delacroix|first1=D|last2=Guerre|first2=J P|last3=Leblanc|first3=P|last4=Hickman|first4=C|title=Radionuclide and Radiation Protection Data Handbook|date=2002|publisher=Nuclear Technology Publishing|location=Ashford|isbn=978-1870965873|edition=2nd}}{{rp|64}} For imaging, multiple gamma camera energy windows are used, typically centred around 93 and 184 keV or 93, 184, and 296 keV.

{{see also|Gallium-68 generator}}

Gallium-68, which has a 68 minutes half-life, is produced in a gallium-68 generator by decay of germanium-68 with a 271 day half-life or by the irradiation of zinc-68 through a low energy cyclotron. Use of a generator means a supply of ⁶⁸Ga can be produced easily with minimal infrastructure, for example at sites without a cyclotron, commonly used to produce other PET isotopes.

It decays by positron emission and electron capture into zinc-68.{{cite book|last1=Bé|first1=M M|last2=Chisté|first2=V|last3=Mougeot|first3=X|last4=Chechev|first4=V|last5=Kondev|first5=F|last6=Nichols|first6=A L|last7=Huang|first7=X|last8=Wang|first8=B|title=Monographie BIPM: Table of radionuclides Vol. 7|date=2013|publisher=Bureau International des Poids et Mesures|location=Paris|isbn=9789282222485|page=33|url=http://www.bipm.org/en/publications/scientific-output/monographie-ri-5.html|access-date=14 September 2017|archive-date=23 August 2017|archive-url=https://web.archive.org/web/20170823110319/http://www.bipm.org/en/publications/scientific-output/monographie-ri-5.html|url-status=live}} Maximum energy of positron emission is at 1.9 MeV.{{rp|65}}

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