MIRD Primer for Absorbed Dose Calculations

Malamud, Herbert

doi:10.1097/00003072-198909000-00027

Cited by 47 publications

(54 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In order to make a comparison of changes of effective dose using different measurement methods, it is necessary to calculate the organ absorbed dose to estimate the effective dose. The calculation of the dose was made via MIRD method as follows [ 27 , 28 ]: …”

Section: Methodsmentioning

confidence: 99%

Internal dosimetry in F-18 FDG PET examinations based on long-time-measured organ activities using total-body PET/CT: does it make any difference from a short-time measurement?

Lin

Weihai

et al. 2021

EJNMMI Phys

View full text Add to dashboard Cite

Purpose A 2-m axial field-of-view, total-body PET/CT scanner (uEXPLORER) has been recently developed to provide total-body coverage and ultra-high sensitivity, which together, enables opportunities for in vivo time-activity curve (TAC) measurement of all investigated organs simultaneously with high temporal resolution. This study aims at quantifying the cumulated activity and patient dose of 2-[F-18]fluoro-2-deoxy-D-glucose (F-18 FDG ) imaging by using delayed time-activity curves (TACs), measured out to 8-h post-injection, for different organs so that the comparison between quantifying approaches using short-time method (up to 75 min post-injection) or long-time method (up to 8 h post-injection) could be performed. Methods Organ TACs of 10 healthy volunteers were collected using total-body PET/CT in 4 periods after the intravenous injection of F-18 FDG. The 8-h post-injection TACs of 6 source organs were fitted using a spline method (based on Origin (version 8.1)). To compare with cumulated activity estimated from spline-fitted curves, the cumulated activity estimated from multi-exponential curve was also calculated. Exponential curve was fitted with shorter series of data consistent with clinical procedure and previous dosimetry works. An 8-h dynamic bladder wall dose model considering 2 voiding were employed to illustrate the differences in bladder wall dose caused by the different measurement durations. Organ absorbed doses were further estimated using Medical Internal Radiation Dose (MIRD) method and voxel phantoms. Results A short-time measurement could lead to significant bias in estimated cumulated activity for liver compared with long-time-measured spline fitted method, and the differences of cumulated activity were 18.38% on average. For the myocardium, the estimated cumulated activity difference was not statistically significant due to large variation in metabolism among individuals. The average residence time differences of brain, heart, kidney, liver, and lungs were 8.38%, 15.13%, 25.02%, 23.94%, and 16.50% between short-time and long-time methods. Regarding effective dose, the maximum differences of residence time between long-time-measured spline fitted curve and short-time-measured multi-exponential fitted curve was 9.93%. When using spline method, the bladder revealed the most difference in the effective dose among all the investigated organs with a bias up to 21.18%. The bladder wall dose calculated using a long-time dynamic model was 13.79% larger than the two-voiding dynamic model, and at least 50.17% lower than previous studies based on fixed bladder content volume. Conclusions Long-time measurement of multi-organ TACs with high temporal resolution enabled by a total-body PET/CT demonstrated that the clinical procedure with 20 min PET scan at 1 h after injection could be used for retrospective dosimetry analysis in most organs. As the bladder content contributed the most to the effective dose, a long-time dynamic model was recommended for the bladder wall dose estimation.

show abstract

Section: Methodsmentioning

confidence: 99%

Internal dosimetry in F-18 FDG PET examinations based on long-time-measured organ activities using total-body PET/CT: does it make any difference from a short-time measurement?

Lin

Weihai

et al. 2021

EJNMMI Phys

View full text Add to dashboard Cite

show abstract

“…The method to conduct the internal dosimetry proposed by the committee of the Society of Nuclear Medicine and Molecular Imaging (MIRD) has been widely used 18,19 . The early MIRD approach was organ‐based, and the latest MIRD approach has been updated to tissues at sub‐organ or even cellular levels 20 .…”

Section: Discussionmentioning

confidence: 99%

Improved accuracy of the biodistribution and internal radiation dosimetry of ¹³N‐ammonia using a total‐body PET/CT scanner

Sun

et al. 2023

Medical Physics

View full text Add to dashboard Cite

BackgroundConventional short‐axis PET typically utilizes multi‐bed multi‐pass acquisition to produce quantitative whole‐body dynamic images and cannot record all the uptake information simultaneously, resulting in errors when fitting the time‐activity curves (TACs) and calculating radiation doses.PurposeThe aim of this study is to evaluate the 13N‐ammonia biodistribution and the internal radiation doses using a 194 cm long total‐body PET/CT scanner (uEXPLORER), and make a comparison with the previous short‐axis PET results.MethodsTen subjects (age 40–74 years) received 13N‐NH3 injection (418.1‐670.81 MBq) and were under a dynamic scan for about 60 min with using a 3‐dimensional whole‐body protocol. ROIs were drawn visually on 11 major organs (brain, thyroid, gallbladder, heart wall, kidneys, liver, pancreas, spleen, lungs, bone marrow, and urinary bladder content) for each subject. TACs were generated using Pmod and the absorbed radiation doses were calculated using Olinda 2.2. To compare with the conventional PET/CT, five points were sampled on uEXPLORER's TACs to mimic the result of a short‐axis PET/CT (15 cm axial FOV, consisted of 9 or 10 bed positions). Then the TACs were obtained using the multi‐exponential fitting method, and the residence time and radiation dose were also calculated and compared with uEXPLORER.ResultsThe highest absorbed organ doses were the pancreas, thyroid, spleen, heart wall, and kidneys for the male. For the female, the first five highest absorbed organ dose coefficients were the pancreas, heart wall, spleen, lungs, and kidneys. The lowest absorbed dose was found in red marrow both for male and female. The simulated short‐axis PET can fit TACs well for the gradually‐changed uptake organs but typically underestimated for the rapid‐uptake organs during the first‐10 min, resulting in errors in the calculated radiation dose.ConclusionuEXPLORER PET/CT can measure 13N‐ammonia's TACs simultaneously in all organs of the whole body, which can provide more accurate biodistribution and radiation dose estimation compared with the conventional short‐axis scanners.

show abstract

“…In terms of applicability, FOV counts could provide an immediate and direct verification of A admin after 90 Y‐radioembolization following 90 Y SPECT/CT imaging, with data collection and analysis procedures that can be fully automated without need for user intervention. While the VOI liver model requires liver segmentation, besides enabling a reliable estimate of A admin , it may also be used to provide a mean dose estimation based on the single‐compartment or the partition model, if the perfused volume and tumor segmentation were accessible 28,29 . The availability of several commercial AI‐based software for whole liver and Couinaud segment segmentation could facilitate a straightforward implementation of the VOI liver ‐based A admin method.…”

Section: Discussionmentioning

confidence: 99%

Predicting the net administered activity in ⁹⁰Y‐radioembolization patients from post‐procedure ⁹⁰Y‐SPECT/CT

et al. 2023

View full text Add to dashboard Cite

BackgroundThe calculation of the net administered activity (Aadmin) in patients undergoing 90Y‐radioembolization is essential for dosimetry and radiation safety, yet current methods for measuring residual 90Y activity are often associated with high uncertainty. Therefore, an accurate, robust, and clinically viable method for the determination of Aadmin across approved 90Y microsphere devices is desirable.PurposeWe report on a novel method to determine Aadmin by leveraging the quantitative capabilities of SPECT/CT to measure 90Y‐emission in vivo from patients following 90Y‐radioembolization with glass or resin microspheres.Methods90Y‐SPECT/CT attenuation‐corrected count data from 147 sequential 90Y‐radioembolization patients was used for this analysis. Aadmin was calculated as part of routine clinical practice via the exposure rate differences between the initial 90Y‐vial and the 90Y‐residual jar. This served as our gold standard measure of Aadmin. Patient data for each microsphere device were separated into training and testing cohorts to first develop regression models and then to independently assess model performance. The training cohorts were divided into four groups: first, based on the microsphere device (glass or resin), and second, based on the SPECT volume used to calculate counts (the full SPECT field of view (FOV) or liver only (VOIliver)). Univariate linear regression models were generated for each group to predict Aadmin based on 90Y‐SPECT data from the training cohorts. Leave‐one‐out cross validation was implemented to estimate variability in model parameters. To assess performance, linear models derived from the training cohort were applied to 90Y‐SPECT data from the testing cohort. A comparison of the models between microspheres devices was also performed.ResultsLinear models derived from the glass and resin training cohorts demonstrated a strong, positive correlation between 90Y‐SPECT image counts and Aadmin for VOIliver and FOV with R2 > 0.98 in all cases. In the glass training cohort, model accuracy (100%—absolute mean prediction error) and precision (95% prediction intervals of mean prediction error) were 99.0% and 15.4% for the VOIliver and 99.7% and 17.5% for the FOV models, respectively. In the resin training cohort, the corresponding values were 98.6% and 16.7% for VOIliver and > 99.9% and 11.4% for the FOV models, respectively. The application of these linear models to 90Y‐SPECT data from the testing cohort showed Aadmin prediction errors to have high accuracy and precision for both microsphere devices. For the glass testing cohort, accuracy (precision) was 96.9% (19.6%) and 98.8% (21.1%) for the VOIliver and FOV models, respectively. The corresponding values for the resin training cohort were 97.3% (26.2%) and 98.5% (25.7%) for the VOIliver and FOV models, respectively. The slope of the linear models between the two microsphere devices was observed to be significantly different with resin microspheres generating 48%–49% more SPECT counts for equivalent 90Y activity based on each device manufacturer's activity calibration process.Conclusion90Y‐SPECT image counts can reliably predict (accuracy > 95% and precision < 18%) Aadmin after 90Y‐radioembolization, with performance characteristics essentially equivalent for both glass and resin microspheres. There is a clear indication that activity calibrations are fundamentally different between the two microsphere devices.

show abstract

MIRD Primer for Absorbed Dose Calculations

Cited by 47 publications

References 0 publications

Internal dosimetry in F-18 FDG PET examinations based on long-time-measured organ activities using total-body PET/CT: does it make any difference from a short-time measurement?

Internal dosimetry in F-18 FDG PET examinations based on long-time-measured organ activities using total-body PET/CT: does it make any difference from a short-time measurement?

Improved accuracy of the biodistribution and internal radiation dosimetry of ¹³N‐ammonia using a total‐body PET/CT scanner

Predicting the net administered activity in ⁹⁰Y‐radioembolization patients from post‐procedure ⁹⁰Y‐SPECT/CT

Contact Info

Product

Resources

About

MIRD Primer for Absorbed Dose Calculations

Cited by 47 publications

References 0 publications

Internal dosimetry in F-18 FDG PET examinations based on long-time-measured organ activities using total-body PET/CT: does it make any difference from a short-time measurement?

Internal dosimetry in F-18 FDG PET examinations based on long-time-measured organ activities using total-body PET/CT: does it make any difference from a short-time measurement?

Improved accuracy of the biodistribution and internal radiation dosimetry of 13N‐ammonia using a total‐body PET/CT scanner

Predicting the net administered activity in 90Y‐radioembolization patients from post‐procedure 90Y‐SPECT/CT

Contact Info

Product

Resources

About

Improved accuracy of the biodistribution and internal radiation dosimetry of ¹³N‐ammonia using a total‐body PET/CT scanner

Predicting the net administered activity in ⁹⁰Y‐radioembolization patients from post‐procedure ⁹⁰Y‐SPECT/CT