The 2026 NRC Rulemaking Wave: What Medical-Use Licensees Need to Know
Between April and July 2026 the NRC issued five proposed rules reaching medical-use licensees under Executive Order 14300. Two of them amend 10 CFR Part 35 at the same time — one rewrites patient release and caregiver dose, the other overhauls authorized-user training. ALARA would be replaced by a graded approach to dose management with an explicit cost-benefit test.
NRC Reciprocity: Form 241 Across State Lines
Reciprocity is how an Agreement State licensee legally does licensed work outside its home state without holding a second full license. Under 10 CFR 150.20, a general license and an NRC Form 241 authorize temporary work in NRC jurisdiction; work in another Agreement State runs through that state's own reciprocity process. The rules on filing, fees, the 180-day limit, and what reciprocity does not cover decide whether a traveling program is compliant.
Breastfeeding Interruption After Radiopharmaceuticals
Some radiopharmaceuticals appear in breast milk and can deliver an ingestion dose to a nursing infant. Interruption recommendations are chosen to keep the infant's effective dose below about 1 mSv, following NRC Regulatory Guide 8.39 and ICRP Publication 106, with radionuclide-specific periods ranging from none to complete cessation for I-131 sodium iodide.
MRI Safety Program: ACR Zones and Roles
An MRI safety program controls four invisible hazards through zones, trained personnel, and implant screening. Here is how to build one around the 2024 ACR Manual on MR Safety and the Joint Commission's 2026 imaging goal — and where a medical physicist fits as your MR Safety Expert.
RPT Shielding for Lu-177, Ra-223, and Ac-225
RPT shielding is a radionuclide- and workflow-specific radiation safety review. Lu-177, Ra-223, and Ac-225 differ in photon emissions, contamination pathways, waste handling, patient workflow, and shielding needs, so each therapy program needs its own source-term, occupancy, and operational-control assessment.
Airborne Radioactivity Areas and Ventilation
An airborne radioactivity area is a regulatory designation with a precise definition tied to the derived air concentration and DAC-hours. Managing it is mostly an engineering-controls problem: ventilation, fume hoods, and negative pressure keep airborne concentrations and internal dose ALARA, with posting, air sampling, and bioassay closing the loop.
Radiation Area Posting and Labeling Rules
Radiation area posting and labeling under 10 CFR Part 20 Subpart J is one of the most frequently cited—and most fixable—areas of radiation safety. This guide explains the dose-rate thresholds that define radiation, high radiation, and very high radiation areas, the exact sign wording required, container labeling rules, and how to classify an area from a survey measurement using inverse-square geometry.
Shipping Radioactive Material: DOT 49 CFR
Shipping and receiving radioactive material is governed by DOT 49 CFR Parts 171–173, NRC 10 CFR Part 71, and the IATA Dangerous Goods Regulations for air. This guide explains package types, White-I/Yellow-II/Yellow-III labeling, the Transport Index, surface dose-rate and contamination limits, hazmat training, and the receiving survey under 10 CFR 20.1906.
Patient Gonadal & Fetal Contact Shielding
For half a century, lead gonadal and fetal contact shields were standard practice in diagnostic radiography. AAPM, NCRP, ACR, and RSNA now recommend discontinuing them as a routine practice — because the benefit is negligible, the shields are usually mispositioned, and they can interfere with automatic exposure control and obscure anatomy in ways that increase dose and force repeats. This is a policy change every RSO and imaging facility has to manage.
Public Dose Limits Under 10 CFR Part 20
The NRC caps radiation dose to individual members of the public at 1 mSv (100 mrem) per year and 0.02 mSv in any one hour in an unrestricted area. Meeting those limits is not enough — a licensee must be able to demonstrate compliance through surveys, calculations, or effluent monitoring, and design shielding and controls to a stricter ALARA goal. This guide explains the limits, the definitions behind them, and how to prove compliance.
Fetal Dose in Medical Imaging: Thresholds
Fetal (conceptus) dose is the radiation dose absorbed by the developing embryo or fetus during a maternal imaging exam. Below roughly 50 mGy there is no measurable increase in malformation or pregnancy-loss risk, and most diagnostic exams fall far below that level—so an informed dose estimate, not reflexive avoidance or termination, should drive patient management.
Radiation Survey Meter Selection Guide
Not all radiation survey meters answer the same question. Learn how GM meters, ion chambers, hybrid meters, x-ray survey sensors, and imaging survey meters work so you can match the right instrument to contamination control, leakage surveys, and shielding verification.
NRC Inspection Prep: An RSO Checklist
NRC and Agreement-State inspectors review the entire 10 CFR Part 35 program — credentials, dosimetry, QC records, sealed-source inventory, surveys, and written directives — not just individual procedures. This guide walks RSOs and program managers through every inspection element, from document binder preparation to corrective-action responses, so the program is ready before the inspector arrives.
Sentinel Events vs Serious Reportable Events
Sentinel events and serious reportable events are converging. Here is what the January 1, 2027 Joint Commission–NQF alignment means for hospital safety reporting, and for radiology, MRI, nuclear medicine, and radiation therapy.
The Radiation Safety Committee Explained
The Radiation Safety Committee is the governance body that holds a medical radioactive-material program accountable. Required for licensees with multiple types of medical use, it brings authorized users, the RSO, nursing, and management to one table to oversee ALARA, dose trends, new uses, and program changes — turning radiation safety from one person's job into an institutional commitment.
Occupational Dose Records & NRC Form 5
Occupational radiation dose recordkeeping is where many otherwise-strong radiation safety programs get cited. The rules live in 10 CFR 20 Subparts L and M: what you record on NRC Form 5, how long you keep it, when you must report to the NRC, and when you must report to the worker. This guide organizes the recordkeeping and reporting requirements, the retention periods, and the dose quantities that make up a defensible occupational dose record.
Written Directives in Nuclear Medicine
A written directive is the dated, signed order an authorized user must complete before certain radiopharmaceutical therapies and I-131 administrations. This guide explains 10 CFR 35.40 and 35.41: when a directive is required, what it must contain, the oral-directive 48-hour rule, the verification procedures, and how directives prevent medical events.
RSO Role: Duties, Authority, and Qualifications
What a Radiation Safety Officer actually does — the authority and responsibilities of 10 CFR 35.24, the 35.50 qualification pathways, ALARA and investigational levels, the Radiation Safety Committee for broad-scope licenses, and the annual program review that keeps a license in good standing.
Radiation Protection for Fluoroscopy Staff
Interventional and cath-lab staff work beside a patient who becomes the dominant source of scattered radiation, and they accumulate some of the highest occupational doses in medicine. Protecting them is a physics problem — scatter geometry, inverse-square distance, lead attenuation — layered onto a regulatory framework in which the eye-lens dose limit is actively diverging between the NRC and international bodies.
Authorized User Training & Experience (10 CFR 35)
Before a physician can order radiopharmaceutical therapy or a physicist can calibrate a therapy unit, they must be named on the radioactive material license as an authorized user or authorized medical physicist. 10 CFR Part 35 Subpart J defines two routes to that status — board certification and a training-and-experience pathway — each with specific hour and case requirements and preceptor attestation.
Radioactive Package Receipt and Wipe Testing
Every radioactive material package arriving at a medical facility must be monitored for external radiation and surface contamination on a defined schedule. A wipe test converts a count-rate reading into removable activity per unit area, which is compared against DOT and NRC limits. This guide explains the survey procedure, the wipe-test math, the action levels, and the records that keep package receipt defensible.
Decay-in-Storage of Radioactive Waste (35.92)
Decay-in-storage (DIS) is the most practical disposal pathway for short-lived medical radioactive waste. Under 10 CFR 35.92 a licensee may hold byproduct material with a half-life of 120 days or less until a surface survey with a suitable meter on its most sensitive scale, no interposed shielding, cannot distinguish it from background — then dispose of it as ordinary trash after removing all radiation labels.
Radioactive Material Spill Response Procedures
A radioactive material spill is a time-sensitive contamination event, and the response depends on whether it is classified as minor or major. This guide explains the major-versus-minor spill criteria, the NRC spill-kit and step-by-step response, decontamination and survey verification, removable-contamination action levels, and the reporting and program requirements an RSO must build in advance.
NRC Medical-Use License Amendments
A radioactive material license is a living document. Adding an authorized user, a new radionuclide, a new room, or a higher possession limit can require a license amendment before the change—while other changes need only a notification. This article maps 10 CFR 35.13 against 35.14, works a possession-limit example, and shows how to keep a medical-use license current and defensible.
ALARA Investigational Levels for Occupational Dose
Investigational Levels I and II are the ALARA action thresholds a radiation safety program sets below the regulatory occupational dose limits, so a rising dose triggers review long before anyone approaches a legal limit. This guide explains the two-tier concept, how licensees typically derive quarterly values as fractions of the 10 CFR 20.1201 limits, who reviews what, and how to document the program under NRC Regulatory Guide 8.10 — with a worked calculation and an example table.
Medical Event Reporting: 10 CFR 35.3045
A medical event is not the same as patient harm — it is a regulatory definition. Under 10 CFR 35.3045, specific dose and percentage thresholds, wrong-patient or wrong-radiopharmaceutical administrations, and leaking sources trigger mandatory notification of the NRC, the referring physician, and the patient on a strict timeline. Knowing the thresholds and building a written-directive workflow that prevents them is core RSO work.
Patient Release After Radiopharmaceutical Therapy
Patient release after radiopharmaceutical therapy is governed by a dose-based limit, not an activity cutoff. This guide explains the 10 CFR 35.75 5 mSv (0.5 rem) release criterion, the three NUREG-1556 / Reg Guide 8.39 methods of demonstrating compliance, the patient-specific dose calculation with effective half-life and an occupancy factor, the 1 mSv written-instruction trigger, and the records you must keep — with a worked I-131 example.
Thyroid Bioassay for Radioiodine Workers
Radioiodine concentrates in the thyroid, so a worker who inhales or ingests I-131 can accumulate a meaningful committed dose to a single organ from a small intake. A thyroid bioassay — a direct measurement of radioiodine in the neck — is the primary tool for detecting and quantifying that intake. This article explains when a bioassay program is required, how measurements are timed and interpreted, and how the committed dose is derived under NRC rules.
Building an ALARA Program for a Medical Facility
ALARA — keeping radiation dose as low as reasonably achievable — is a regulatory expectation, not a slogan. A defensible ALARA program defines management commitment, dose constraints, investigational levels, time-distance-shielding controls, monitoring, training, and periodic review. This guide explains how to build one that satisfies NRC or Agreement State requirements and actually reduces dose.
Lu-177 PSMA Therapy: Dosimetry & Safety
Lu-177 PSMA-617 (Pluvicto) is a beta-emitting radioligand therapy for PSMA-positive metastatic castration-resistant prostate cancer. Because Lu-177 pairs a therapeutic beta particle with imageable low-energy gammas, treatment planning couples MIRD-based organ dosimetry — where the kidneys and salivary glands are the dose-limiting organs — with an outpatient radiation-safety workflow built on patient-release calculations, contamination control, and NRC medical-use requirements.
Pregnant Radiation Worker: Dose Limits
A pregnant radiation worker can continue working safely in most medical radiation environments, but only under a deliberate program: voluntary written declaration, the 5 mSv embryo/fetus dose limit, fetal dosimetry, and ALARA controls. The decision to declare is the worker's alone, and the radiation safety program's job is to make the safe path the easy path.
Survey Meter Calibration Programs
A survey instrument is only as trustworthy as its calibration. A defensible program covers full calibration before first use, annually, and after repair; routine constancy and operational checks between calibrations; NIST-traceable standards; and documentation that survives an inspection. This guide explains the regulatory basis, the math, and how to build the program.
High Radiation Area Access Controls
A high radiation area is not just a posting problem — it triggers engineered access controls under 10 CFR 20.1601, and a very high radiation area demands additional measures under 20.1602. This guide covers the exact dose thresholds, the control options a licensee may choose, where these areas arise in medical facilities, and how the RSO documents compliance.
Airborne Effluent Releases and Public Dose
Nuclear medicine, PET, and cyclotron facilities routinely release small amounts of radioactive gases and vapors to the environment through hoods and stacks. NRC regulations set a clear framework: a 100 mrem per year public dose limit, a separate 10 mrem per year constraint on air emissions, and two accepted ways to demonstrate compliance, including an effluent-concentration method keyed to Appendix B. Understanding which limit applies, and how the sum-of-ratios method works, keeps a release program defensible.
Extremity Dosimetry in Nuclear Medicine
Nuclear medicine staff receive their highest radiation doses to the fingertips while drawing, dispensing, and injecting radiopharmaceuticals. This guide covers the extremity dose limit, ring-badge monitoring and placement, why ring dosimeters underestimate fingertip dose, and the practical controls that keep hands ALARA.
Postmortem Radiation Safety After Radionuclide Therapy
When a patient dies soon after radiopharmaceutical therapy, the radioactivity does not stop at the door. Autopsy, embalming, burial, and cremation each create their own exposure and contamination pathways for pathologists, morticians, and the public. This is the radiation safety officer's framework for estimating residual activity, deciding what precautions apply, and closing a regulatory gap that no single U.S. rule fully covers.
Effective Dose & ICRP Tissue Weighting Factors
Effective dose is the most used and most misused quantity in radiation protection. It weights organ-level equivalent doses by ICRP 103 tissue weighting factors to produce a single whole-body index of stochastic risk. This guide explains how equivalent dose and effective dose are computed, the current tissue and radiation weighting factors, how they changed from ICRP 60, and the crucial limits on using E to estimate an individual patient's risk.
Planned Special Exposures Under 10 CFR 20.1206
A planned special exposure is the narrow, tightly controlled mechanism that lets a licensee authorize a worker to exceed the annual occupational dose limits in an exceptional situation. This guide explains the 10 CFR 20.1206 dose caps, the preconditions, the prior-dose determination, and the recordkeeping and reporting that make a PSE defensible.
Radiation Safety Training Programs
A radiation safety training program is the documented system that instructs workers before they begin radiation work and refreshes them annually, as required by 10 CFR 19.12. This guide explains who must be trained, the regulatory basis, effective content, recordkeeping, competency assessment, and how training is examined during NRC and Agreement State inspections.
Cumulative Patient Radiation Dose Tracking
Patients who undergo many imaging studies can accumulate a cumulative effective dose above 100 mSv, the level at which the IAEA-convened study of recurrent imaging says organ doses are typically in a range at which radiation effects are of concern. There is no regulatory dose limit for patients, so tracking, justification, and optimization — not a hard cap — are the tools. This is what cumulative dose means, how to compute it, and how to build a program around it.
Y-90 Radioembolization Radiation Safety
Yttrium-90 radioembolization is a pure beta-emitting therapy, and its radiation safety program looks nothing like a gamma-emitter's. This guide explains Y-90's decay physics, why low-Z shielding and contamination control matter more than lead walls, the dose-assay and post-procedure survey workflow, patient release, and the NRC and Agreement State framework for a defensible program.
Skin Dose from Radioactive Contamination
Skin contamination is a dose problem a personnel badge never sees. When a radionuclide lands on skin, the dose that matters is the shallow-dose equivalent to the sensitive basal layer at 7 mg/cm², averaged over 10 cm², and it is dominated by beta and low-energy photon emissions that never reach a deep-dose dosimeter. This guide explains how skin dose is defined, how it is assessed with VARSKIN-class tools, the regulatory limit and averaging rules, and the practical response that keeps a spill from becoming a recordable dose.
The Radioactive Drug Research Committee (RDRC)
The Radioactive Drug Research Committee (RDRC) is the FDA-approved pathway under 21 CFR 361.1 for basic research with radioactive drugs without an IND. This guide explains RDRC scope, the pharmacologic and radiation dose limits for adults and minors, committee composition, subject and reporting rules, and how RDRC approval fits alongside the IRB and the facility's radioactive-material license.
The Linear No-Threshold (LNT) Model
The linear no-threshold model assumes cancer risk rises in direct proportion to dose with no safe threshold. It is the scientific backbone of dose limits and ALARA, and recent expert reviews continue to endorse it for radiation protection while acknowledging its low-dose uncertainty.
NRC Enforcement: Violations & Civil Penalties
When the NRC finds a violation, what happens next follows a defined process: the violation is classified by significance, dispositioned as a minor violation, a non-cited violation, or a cited Notice of Violation, and — for the most significant cases — assessed for a civil penalty or made the subject of an order. Understanding that escalation ladder is what lets an RSO respond correctly instead of overreacting or underreacting.
NRC Occupational Dose Limits: 10 CFR Part 20
10 CFR Part 20 sets the federal radiation dose limits every NRC and Agreement State licensee must meet: the 5 rem annual TEDE limit for workers, separate lens and skin limits, the embryo/fetus limit for a declared pregnant worker, and the public dose limits. This guide explains each limit, the monitoring thresholds that trigger dosimetry, and how ALARA goes beyond the numbers.
NRC Part 35 Recordkeeping Requirements
A compliant medical-use radiation safety program is only as good as its records. This guide maps the 10 CFR Part 35 Subpart L recordkeeping requirements — which record each activity generates, the exact retention period, and the Part 20 cross-references — so RSOs and nuclear medicine departments can build a records system that survives an NRC or Agreement State inspection.
Instructions to Workers: 10 CFR Part 19 & Form 3
10 CFR Part 19 is the worker-facing side of the NRC's radiation rules: the notices a licensee must post, the instructions workers must receive, and the dose reports they are entitled to. It is one of the most commonly cited gaps at inspection, precisely because it is easy to assume it is handled. This guide covers what Part 19 requires, including NRC Form 3, the 1 mSv instruction threshold, and worker dose reports.
Annual Radiation Protection Program Audit
The annual radiation protection program review required by 10 CFR 20.1101(c) is not a paperwork ritual. It is a performance-based audit of both the content and the real-world implementation of your radiation safety program, and it is one of the first things an NRC or Agreement State inspector asks to see.
OSL vs TLD Personnel Dosimeters: Physics and QC
OSL and TLD personnel dosimeters both store energy from radiation in crystal traps and release it as light for readout, but they differ in how that light is stimulated, whether the signal survives reanalysis, and how they respond to photon energy. Understanding the luminescence physics behind each — and the NRC monitoring thresholds and NVLAP performance testing that govern them — is what lets a radiation safety program choose and use them defensibly.
Sealed Source Leak Testing & Inventory
Sealed source leak testing and physical inventory are two of the most routine, and most commonly cited, obligations in a materials license. Leak testing confirms a source is intact by wiping it and checking for removable contamination above the 185 Bq (0.005 microcurie) limit; the semiannual inventory confirms every source is accounted for. This guide explains the 10 CFR 35.67 requirements, the exemptions, the recordkeeping rules, and how an RSO builds a defensible program.
Occupational Eye-Lens Dose in Fluoroscopy
The lens of the eye is one of the most radiosensitive tissues in the body, and interventional fluoroscopy operators can accumulate enough scatter dose to risk cataract. After ICRP lowered the recommended occupational eye-lens limit to 20 mSv per year, monitoring with the Hp(3) quantity, leaded eyewear, ceiling-suspended shields, and good technique became central to staff radiation protection — even though the U.S. NRC limit remains 150 mSv per year.
Radiopharmaceutical Extravasation: Dose & Reporting
Radiopharmaceutical extravasation deposits part of an injected dose into soft tissue instead of the bloodstream, and in significant events the local absorbed dose can reach several gray. This is a radiation-safety and dosimetry problem: knowing when to identify, quantify, document, and report an extravasation protects patients and keeps a nuclear medicine program defensible.
Surface Contamination Limits & Equipment Release
Releasing surveyed equipment for unrestricted use is a routine but frequently misunderstood radiation safety task. The classic surface contamination values, the dose-based license-termination criterion, and the separate transport limits answer different questions. This guide explains the numbers, why Regulatory Guide 1.86 was withdrawn but its values persist, how to convert a smear count to removable contamination, and how to build a defensible equipment-release procedure.
Radiation Protection Survey: Shielding Check
A radiation protection survey is the post-construction verification that closes the loop on a shielding design: the physicist measures dose rates in occupied areas around a newly installed x-ray, CT, or radioactive-material room, scales the measurements to realistic weekly workload and occupancy, and confirms the as-built barriers meet NCRP design goals and regulatory dose limits before clinical use begins.
Ac-225 Targeted Alpha Therapy: Physics & Safety
Actinium-225 targeted alpha therapy exploits the short range and high linear energy transfer of alpha particles to kill tumor cells while sparing nearby tissue. Its four-alpha decay chain, recoiling radioactive daughters, and low-but-nonzero photon output make Ac-225 a distinctive physics, dosimetry, and radiation-safety problem that differs from Lu-177 and Ra-223 therapy.
Caregiver Dose After Radiopharmaceutical Therapy
When a patient is released after I-131 or Lu-177 therapy, the radiation source goes home. Family members, caregivers, and visitors can receive dose from the released patient, and a defensible program manages it with the right dose constraints and written instructions. This guide explains the 5 mSv release criterion, the 1 mSv instruction trigger, the comforter-and-carer constraint, and how to keep household doses ALARA.
Lead Apron QC: Testing and Rejection Criteria
Protective aprons only work if they are intact. This guide covers lead apron integrity testing: inspection methods, dose-based rejection criteria for holes and tears over critical organs, lead-equivalence standards under IEC 61331, inspection frequency, and how to build a defensible protective-garment QC program.
External Dose Control: Time, Distance, Shielding
Time, distance, and shielding are the three levers that control external radiation dose, and each one is quantifiable. Dose is proportional to time, falls with the inverse square of distance, and drops exponentially through shielding. Understanding the math turns ALARA from a slogan into a set of decisions a radiation safety program can defend against the 10 CFR Part 20 dose limits.
Sewer Disposal of Radioactive Material
Releasing licensed radioactive material into the sanitary sewer is permitted under 10 CFR 20.2003, but only within tight limits. The material must be readily soluble or dispersible, the monthly average concentration must stay below Appendix B Table 3 values, mixtures must satisfy a sum-of-fractions test, and total annual releases are capped. This guide explains the rule, the math, the records, and the common RSO mistakes.
Reporting Radiation Incidents to the NRC
NRC regulations set specific, tiered timeframes — immediate, 24-hour, and 30-day — for reporting radiation overexposures, lost or stolen licensed material, and doses that exceed regulatory limits. Knowing which threshold triggers which report, and having the phone numbers and written-report content ready before an event, is a core radiation safety officer responsibility.
ALI, DAC & Internal Dose Limits (10 CFR 20)
Internal radiation dose limits are hard to apply directly, so 10 CFR 20 converts them into two practical quantities: the annual limit on intake (ALI) and the derived air concentration (DAC). This guide explains how ALI and DAC are defined in Appendix B, how DAC-hours track intake against the occupational dose limit, when individual monitoring is required, and how the SUM of internal and external dose forms the total effective dose equivalent.
Radioactive Waste in Nuclear Medicine
A practical, answer-first guide to managing radioactive waste in nuclear medicine — decay-in-storage, sanitary-sewer release, licensed disposal and transfer, and return-to-supplier — with the worked decay math, a pathway comparison table, and the NRC and Agreement State rules that govern each route.
MARSSIM Final Status Surveys Explained
A MARSSIM final status survey is how a facility proves a site is clean enough to release. This guide walks through the NUREG-1575 Revision 2 framework: survey-unit classification, derived concentration guideline levels, the Sign and Wilcoxon Rank Sum tests, the Data Quality Objectives process, and the worked statistics that decide whether a survey unit passes.
Low-Level Waste Classification: 10 CFR Part 61
Most nuclear-medicine waste never reaches a disposal site because decay-in-storage handles it, but the material that outlives the 120-day rule must be classified under 10 CFR 61.55 as Class A, B, or C. This guide explains the waste-classification tables, the sum-of-fractions rule, and how decay-in-storage and Part 61 fit together.
Nationally Tracked Sources and the NSTS
The National Source Tracking System is the NRC's cradle-to-grave ledger for the most dangerous sealed sources — Category 1 and Category 2 quantities of radioactive material. This guide explains what makes a source nationally tracked, the close-of-next-business-day transaction reporting on NRC Form 748, the annual inventory reconciliation, and how NSTS tracking differs from 10 CFR Part 37 security and its aggregation rule.
Stochastic vs Deterministic Radiation Effects
Stochastic effects such as cancer are modeled as having no dose threshold, so their probability rises with dose while severity does not. Deterministic tissue reactions such as cataract and skin injury have practical thresholds, and their severity climbs with dose once the threshold is crossed. The distinction is the physics behind every dose limit, ALARA decision, and patient risk conversation.
Nuclear Medicine Area Surveys: 35.70 & 20.1501
A nuclear medicine survey program has two engines: the end-of-day ambient dose-rate survey required by 10 CFR 35.70 in written-directive areas, and the broader radiation and contamination surveys required by 10 CFR 20.1501. Knowing which rule drives which survey, with what instrument, frequency, and action level, keeps the program defensible.
NRC Broad Scope Licenses: Types A, B, and C
A broad scope license under 10 CFR Part 33 lets an institution add radionuclides, uses, and authorized users through its own Radiation Safety Committee instead of filing an NRC amendment for every change. That flexibility comes with weighty responsibility: Types A, B, and C differ in quantity limits, committee requirements, and the depth of program a licensee must run to earn and keep the authority.
Radiation Risk Communication in Imaging
Communicating imaging radiation risk well means neither inflating it nor dismissing it. Effective dose is a population planning quantity, not an individual risk prediction; at diagnostic doses the modeled risk is small and uncertain, and the benefit of an indicated exam almost always dominates. A defensible script leads with benefit, frames dose against natural background, and answers the patient's real question.
Occupational Radiation Exposure Monitoring
A practical guide to designing and maintaining an effective occupational radiation monitoring program in healthcare—from dosimeter selection and badge placement to ALARA investigation levels and NRC recordkeeping.
Radioactive Spill Response in Nuclear Medicine
A practical, answer-first guide to radioactive spill response and decontamination in nuclear medicine, covering containment, survey-to-contamination math, wipe-test action levels, waste handling, and NRC and state regulatory compliance.
Lead Shielding Design for CT and PET/CT
How medical physicists design lead shielding for CT, fluoroscopy, interventional radiology, PET/CT, and radionuclide therapy—covering workload, use factor, occupancy, distance, the NCRP 147 transmission equation, tenth-value-layer barrier thickness, and a worked numeric example under 10 CFR 20.
Radioactive Material License Renewal
Renewing a radioactive material license is not a formality. Under the NRC's timely-renewal rule (10 CFR 2.109), filing a complete renewal at least 30 days before expiration keeps the license in effect while the application is reviewed. A defensible renewal reconciles possession limits, authorized users, procedures, and the ALARA program with how the facility actually operates.
Decommissioning a Radioactive Materials License
Closing a radioactive-materials program and terminating an NRC or Agreement State license is a defined, dose-based process. The licensee must decommission the use area, demonstrate that residual radioactivity meets the radiological criteria for license termination through a final status survey, and document compliance using derived concentration guideline levels and detection-capable instrumentation.
Sentinel Node Surgery: Staff Radiation Safety
Sentinel lymph node biopsy injects only tens of megabecquerels of Tc-99m, so measured doses to surgeons, scrub staff, and pathologists sit far below regulatory limits. But 'very low' is not 'zero': a defensible program still needs dose data, specimen-handling rules, and a documented ALARA basis for why the operating-room team is not classified as radiation workers.
Well Counter QC for Bioassay and Wipe Tests
The scintillation well counter is the low-activity workhorse of a nuclear medicine department—it counts wipe tests, I-131 thyroid bioassays, and blood samples. Its quality control is a small set of interlocking tests: energy peaking, chi-square constancy, efficiency (sensitivity) calibration, background, and minimum detectable activity. Each rests on counting statistics, and each protects a different regulatory or clinical decision.
Nuclear Medicine Hot Lab Design and Safety
The hot lab is where nuclear medicine radiation safety is won or lost. A defensible design sizes shielding, workflow zoning, contamination control, and instrumentation to the actual radionuclides handled — Tc-99m, F-18, I-131, and Lu-177 each pose different external-dose and contamination problems — and verifies the built room with a post-construction survey.
Diagnostic X-Ray Room Shielding: NCRP 147
Diagnostic X-ray room shielding follows NCRP Report 147, which sets weekly air-kerma design goals, distinguishes primary from secondary barriers, and converts a required transmission into a lead or concrete thickness using workload, use factor, occupancy, distance, and the Archer transmission model.
Minimum Detectable Activity for Contamination Surveys
Minimum detectable activity (MDA) is the smallest amount of radioactivity a counting setup can reliably distinguish from background — the statistical floor that decides whether a contamination survey can actually see the limit it must enforce.
Dosage Determination Under 10 CFR 35.63
Before any unsealed radiopharmaceutical is administered, 10 CFR 35.63 requires the licensee to determine and record its activity — by direct measurement in a calibrated dose calibrator or by decay correction from a licensed preparer — and generally to keep it within 20% of the prescribed dosage. This short, deceptively simple regulation is where dose-calibrator QC, recordkeeping, written directives, and medical-event avoidance all converge.
Neutron Safety at PET Cyclotron Facilities
A PET cyclotron is the one place in a medical imaging enterprise where fast neutrons dominate the radiation safety picture. Proton-induced reactions during F-18 production create an intense neutron field and activate the vault, targetry, and even the air — hazards that behave nothing like the 511 keV photons downstream, and that demand neutron-specific dose quantities, shielding, and monitoring.
Patient Radiation Alarms After Nuclear Medicine
Patients who have had a nuclear medicine study or radionuclide therapy can set off sensitive radiation detectors at airports, borders, and secure buildings for days to months afterward. NRC Regulatory Guide 8.39 expects licensees to warn them and, when appropriate, issue a wallet card documenting the treatment.
Radiation Dose Quantities & Units Explained
Absorbed dose, equivalent dose, and effective dose answer different questions, use different weighting factors, and are easy to confuse. This guide defines each quantity and its SI unit, works the ICRP 103 math, explains the operational quantities used in monitoring, and clarifies why the NRC's 10 CFR Part 20 quantities differ from the current ICRP recommendations.
Common Radiation Safety Violations to Avoid
A practical guide to the radiation safety violations most often cited during imaging and nuclear medicine inspections, mapped to the exact 10 CFR Part 20 and Part 35 sections, with the root causes and corrective actions that keep facilities off the enforcement list.
NRC Radioactive Material License: Medical Use
A practical guide to obtaining and maintaining an NRC or Agreement State radioactive material license for medical use, covering 10 CFR Part 35 use categories, the NRC Form 313 / NUREG-1556 application, RSO and Authorized User requirements, ALARA, source security, amendments, and ongoing compliance.
PET/CT Shielding Calculations: TG-108 and NCRP 147
PET/CT shielding is a mixed-modality problem: the injected patient, hot lab, uptake rooms, scanner room, and CT subsystem can all contribute to adjacent-area dose. A defensible design combines PET-specific TG-108 methods, CT shielding principles from NCRP 147, realistic workload and occupancy assumptions, and post-construction verification.
Florida Radiation Safety Rules for Imaging Centers
What imaging centers in Florida must do to comply with radiation safety regulations, from 64E-5 equipment registration and personnel licensure to annual physics evaluations and inspections.
Mobile Nuclear Medicine Service: NRC Compliance
A mobile nuclear medicine service brings byproduct material and imaging to a client's site under the mobile provider's own radioactive material license. 10 CFR 35.80 sets the compliance backbone: a management letter from each client, instrument checks before use at every address, area surveys before leaving, and defined records — all layered on Part 20 dose limits, DOT transport rules, and Agreement State reciprocity.
Respiratory Protection for Airborne Radioactivity
When engineering controls cannot fully contain airborne radioactive material, respirators become the last line of defense against internal exposure. This guide explains the ALARA hierarchy of controls in 10 CFR 20 Subpart H, the assigned protection factors in Appendix A, the DAC-hour intake math, and the program elements — fit testing, bioassay, air sampling, and medical clearance — that a compliant respiratory protection program requires.
Radioactive Source Security: 10 CFR Part 37
10 CFR Part 37 sets security requirements for category 1 and category 2 quantities of radioactive material. Compliance turns on aggregating your sources against the Appendix A thresholds, granting unescorted access only to trustworthy and reliable individuals, maintaining security zones with monitoring and immediate detection, coordinating with local law enforcement, and protecting material in use and transit.
X-Ray Machine Registration & State Inspections
The regulation of diagnostic X-ray machines confuses many facilities because it splits across agencies: the FDA sets federal performance standards on the equipment itself, states register and inspect the machines in use, and the NRC governs only radioactive material — not machines. This guide maps who regulates what, the key 21 CFR 1020 dose and leakage limits, how state registration and inspection work, and where MQSA imposes a federal physicist survey.
Securing Licensed Material: 10 CFR 20.1801/20.1802
Securing and controlling licensed material is one of the most frequently cited requirements in NRC and Agreement State inspections. 10 CFR 20.1801 governs stored material and 20.1802 governs material in use. Both apply to every quantity of licensed material a facility possesses, not just the large sources covered by Part 37, and both come down to a simple test: is the material either secured or under someone's constant watch?
Self-Contained Irradiator Radiation Safety
A self-contained blood or research irradiator hides a very large sealed source behind heavy shielding. It is not a Part 36 irradiator, its Cs-137 source is a Part 37 security concern, and its dose delivery drifts with source decay — three facts that shape the whole radiation safety program.
USP 825: Radiopharmaceutical Compounding Safety
USP General Chapter 825 is the compounding standard written specifically for radioactive drugs. It defines how nuclear pharmacies and nuclear medicine departments prepare, compound, dispense, and repackage radiopharmaceuticals safely—reconciling the sterile-compounding engineering controls of USP 797 with the radiation-safety realities of short half-lives, contamination control, and NRC and FDA oversight. This guide explains the chapter's scope, its place among the USP compounding chapters, and how a facility builds a compliant program.