Comparison of 99mTc Injected Activity with Prescribed Activity in Four Types of Nuclear Medicine Exams

Background: 99mTc is a radioactive isotope that is obtained by eluting a 99Mo/99mTc generator. (PINSTECH, Islamabad) and used for radionuclide scanning. Objectives: The objective of this work is to study the uncertainties in 99mTc activity that exist due to time delay between injection preparation and administration to patients, during the process of gamma camera scanning. Methods: Lead canisters were used for storing elution vials and dose calibrator for measuring 99mTc activity in mCi. The activity of preparing 99mTc injection and its administration to patients were compared with the prescribed values of activity recommended in the Society of Nuclear Medicine procedure guidelines. Results: This study showed that uncertainty in the activity existed in one thyroid patient, 38 bone patients, 5 renal patients and 45 cardiac patients. Conclusion: This uncertainty in activity exists due to time delay between injection preparation and administration to patients, as well as due to residual radionuclide that is not injected into patients and remains in the syringe.

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Quantification of Patient Specific Dosimetry in Radionuclide Therapy: A Phantom Study

Bangladesh Journal of Nuclear Medicine ◽

10.3329/bjnm.v17i2.28199 ◽

2016 ◽

Vol 17 (2) ◽

pp. 134-137

Author(s):

Kamila Afroj Quadir ◽

Brian Zimmermann ◽

Md Nahid Hossain ◽

Md Nurul Islam ◽

Ferdoushi Begum ◽

...

Keyword(s):

Nuclear Medicine ◽

Radionuclide Therapy ◽

Gamma Camera ◽

Absorbed Dose ◽

Calibration Factor ◽

Patient Specific ◽

Dose Calibrator ◽

Spect Image ◽

Reconstruction Quantification ◽

Spect System

The accuracy of patient specific dosimetry is correlated with measured organ activity by gamma camera and SPECT system. The assessment of the radiation-absorbed dose by patients undergoing nuclear medicine investigation requires accurate measurement of organ activity, biokinetics data, as well as physical data. Activities were estimated by using Ba-133 phantom with both planar and SPECT systems. The objective of the study was to measure the activities of Ba-133 from gamma camera images using both planar and SPECT studies and compare the reference values with the dose calibrator values to quantify the actual activity with gamma camera. Four Ba-133 sources of different volume and activity 379, 950, 1219 and 1150 KBq are measured by using Veenstra Instrument VDC 404 Dose Calibrator. The second smallest source was used to determine the calibration factor. Acquisition, corrections, reconstruction, quantification and measuring activity from both planar and SPECT imaging were done with all Ba-133 sources in air. The activities of the Ba-133 sources were also measured using I-131 settings of the dose calibrator. The measurement of the second smallest source was used to obtain the calibration factor. This calibration factor was used to convert the planer and SPECT image count of all the sources into activities. In case of both planar and SPECT gamma camera, the measurements showed good correlations and all the values varied within ±15%. Planer and SPECT gamma camera image counts can be used to calculate activity in the organ. This information can play a very significant role in evaluating image based patient specific dosimetry in radionuclide therapy.Bangladesh J. Nuclear Med. 17(2): 134-137, July 2014

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U.S. PET/CT and Gamma Camera Diagnostic Reference Levels and Achievable Administered Activities for Noncardiac Nuclear Medicine Studies

Radiology ◽

10.1148/radiol.2019190623 ◽

2019 ◽

Vol 293 (1) ◽

pp. 203-211 ◽

Cited By ~ 1

Author(s):

Murray D. Becker ◽

Priscilla F. Butler ◽

Mazen Siam ◽

Dustin A. Gress ◽

Munir Ghesani ◽

...

Keyword(s):

Nuclear Medicine ◽

Gamma Camera ◽

Diagnostic Reference Levels ◽

Reference Levels ◽

Pet Ct

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Nuclear medicine

10.1093/med/9780199642489.003.0070 ◽

2013 ◽

Author(s):

Adil Al-Nahhas ◽

Imene Zerizer

Keyword(s):

Nuclear Medicine ◽

Gamma Camera ◽

Structural Changes ◽

Response To Treatment ◽

Inflammatory Conditions ◽

Area Of Interest ◽

Positron Emission ◽

Lung Scan ◽

Monitoring Response

The application of nuclear medicine techniques in the diagnosis and management of rheumatological conditions relies on its ability to detect physiological and pathological changes in vivo, usually at an earlier stage compared to structural changes visualized on conventional imaging. These techniques are based on the in-vivo administration of a gamma-emitting radionuclide whose distribution can be monitored externally using a gamma camera. To guide a radionuclide to the area of interest, it is usually bound to a chemical label to form a 'radiopharmaceutical'. There are hundreds of radiopharmaceuticals in clinical use with different 'homing' mechanisms, such as 99 mTc HDP for bone scan and 99 mTc MAA for lung scan. Comparing pre- and posttherapy scans can aid in monitoring response to treatment. More recently, positron emission tomography combined with simultaneous computed tomography (PET/CT) has been introduced into clinical practice. This technique provides superb spatial resolution and anatomical localization compared to gamma-camera imaging. The most widely used PET radiopharmaceutical, flurodeoxyglucose (18F-FDG), is a fluorinated glucose analogue, which can detect hypermetabolism and has therefore been used in imaging and monitoring response to treatment of a variety of cancers as well as inflammatory conditions such as vasculitis, myopathy, and arthritides. Other PET radiopharmaceuticals targeting inflammation and activated macrophages are becoming available and could open new frontiers in PET imaging in rheumatology. Nuclear medicine procedures can also be used therapeutically. Beta-emitting radiopharmaceuticals, such as yttrium-90, invoke localized tissue damage at the site of injection and can be used in the treatment of synovitis.

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