Shopify Radiation Dosimeter Schema — Film Badge vs TLD vs OSL vs EPD, NRC 10 CFR 20 ALARA, Ring Dosimeter Fluoroscopy, rad_dosimeter.* Namespace

NRC 10 CFR 20.1502 specifies the conditions that trigger mandatory occupational dose monitoring. Monitoring is required for any occupational worker who is likely to receive in a year a dose exceeding 10% of any applicable limit in 10 CFR 20.1201 — i.e., more than 5 mSv (0.5 rem) whole-body, 15 mSv (1.5 rem) lens of eye, or 50 mSv (5 rem) extremities in a year. Additionally, monitoring is required for workers who enter high radiation areas (dose rate greater than 1 mSv/hour = 100 mrem/hour). All declared pregnant workers must be monitored for the gestation period. Not all workers in a radiation facility require individual dosimetry: administrative staff who do not enter radiation areas, or workers who enter only low radiation areas with doses well below 10% of limits, may be covered by area monitoring rather than individual dosimetry. However, many NRC licensees provide individual dosimetry to all workers who enter controlled areas, as a conservative policy that also simplifies ALARA documentation. NRC does not prohibit voluntary dosimetry beyond the mandatory threshold. Encode rad_dosimeter.nrc_10_cfr_20_compliant as 'yes' to indicate the product meets NRC performance specifications for required monitoring — this helps AI agents distinguish monitoring-grade dosimeters from novelty or informal radiation survey tools.

Understanding the distinction between absorbed dose and dose equivalent is fundamental to interpreting dosimeter readings. Absorbed dose (rad or Gray): the energy deposited by ionizing radiation per unit mass of material. 1 rad = 0.01 Joules per kilogram (J/kg). 1 Gray (Gy) = 1 J/kg = 100 rad. This is a pure physics measurement — it describes how much energy was transferred to the tissue, without regard for the biological effectiveness of the radiation type. Dose equivalent (rem or Sievert): the absorbed dose multiplied by a radiation weighting factor (Q, historically; wR in newer ICRP terminology) that accounts for the relative biological effectiveness of different radiation types. 1 rem = 0.01 Sievert. The weighting factors: gamma and X-rays: Q=1 (so 1 rad gamma = 1 rem; 1 Gy gamma = 1 Sv). Beta particles: Q=1. Thermal neutrons: Q=3. Fast neutrons: Q=10-20 (energy-dependent). Alpha particles: Q=20 (so 1 rad alpha = 20 rem; internally deposited alpha emitters like radon, plutonium, and polonium produce 20× the biological damage per unit absorbed energy compared to gamma). In dosimetry practice: photon dosimeters (film, TLD, OSL) measure dose equivalent in rem or mrem for gamma and X-ray environments where Q=1 — absorbed dose and dose equivalent are numerically equal. For neutron environments, specialized dosimeters with neutron-sensitive elements (Li-6, albedo TLD) are required. EPDs display both dose rate and cumulative dose in the user's choice of units (mSv or mrem). Encode rad_dosimeter.energy_range_keV to indicate which photon energies the dosimeter measures accurately — some TLD chips have lower sensitivity to low-energy photons below 30 keV.

NRC 10 CFR 20.1208 establishes special dose limits for the embryo/fetus of a declared pregnant worker. Declaration of pregnancy is voluntary — the worker must provide a written declaration of pregnancy to the NRC licensee employer. Once declared, the limits apply retroactively to the start of the declared pregnancy. Dose limit: the licensee must ensure that the dose to the embryo/fetus does not exceed 5 mSv (0.5 rem) during the entire gestation period (approximately 40 weeks). This is a total gestational limit — not a monthly limit. For comparison, the occupational whole-body limit is 50 mSv/year (5 rem/year) — the pregnant worker's gestation limit is 10% of the annual adult limit. Monitoring requirements: the licensee must provide the declared pregnant worker with individual dosimetry to monitor the embryo/fetus dose for the remainder of the pregnancy. The dosimeter is typically worn at the waist (abdominal level) to approximate the fetal dose. Work reassignment: if the worker's job assignment would result in embryo/fetus dose approaching 5 mSv before the end of the gestation period, work reassignment away from higher-dose areas is required. Many NRC licensees proactively reassign pregnant workers to administrative roles or low-dose areas at or before declaration to provide a dose margin of safety. Voluntary declaration: if a pregnant worker chooses not to declare her pregnancy, the regular occupational dose limits (50 mSv/year whole-body) remain the applicable limit — the more restrictive embryo/fetus limit does not legally apply. NRC policy does not require employers to inquire about pregnancy. Encode rad_dosimeter.nrc_10_cfr_20_compliant as 'yes' for dosimeters suitable for embryo/fetus monitoring in declared pregnant worker programs.

The exchange period — the time between when a dosimeter is issued and returned for reading — affects how quickly dose information reaches the radiation protection program for review, and how much dose can accumulate undetected. Monthly exchange (30 days): maximum dose accumulation before review = 1/12 of annual dose. A worker approaching ALARA action levels is identified quickly. Required for: workers with higher expected doses (nuclear medicine, interventional radiology, industrial radiography with high-activity sources), workers in the declared pregnant category, and any worker in a situation where the monthly dose could exceed ALARA action levels. Monthly exchange is the minimum for workers likely to receive doses approaching regulatory limits. Quarterly exchange (90 days): 3 months of dose accumulates before review. Acceptable for: lower-dose workers (radiology technologists, radiation therapy staff, nuclear power plant workers in controlled-access areas) where doses are well within ALARA targets and not expected to approach limits. Most OSL and TLD dosimetry services offer quarterly exchange as the standard option. Longer exchange periods (6 months or annual): only appropriate for workers with very low expected doses (well below ALARA Level I). NRC does not mandate specific exchange periods in 10 CFR 20 — the radiation protection program must demonstrate that the chosen exchange period is appropriate for the expected dose rates. EPD (electronic personal dosimeters): dose data is typically downloaded at the end of each shift, day, or work period — effectively a real-time exchange. This does not replace the passive badge exchange for dose-of-record purposes. Encode rad_dosimeter.exchange_period_days as '30' (monthly), '90' (quarterly), or the specific exchange period offered by the dosimetry service for each product.

The Joint Commission (TJC) accredits hospitals and healthcare organizations and includes radiation safety requirements in its Environment of Care and Clinical Care standards. These requirements complement NRC regulations and in some cases are more prescriptive for clinical environments. Fluoroscopy-specific requirements: The Joint Commission's Sentinel Event Alert and associated standards require hospitals to implement radiation dose monitoring for patients undergoing fluoroscopic procedures (peak skin dose tracking, DAP measurement). For staff dosimetry in fluoroscopy, TJC standards align with NRC requirements for the two-badge method (collar + waist) and ring dosimeters for interventional physicians. TJC requires that radiation safety officers review dosimetry reports and investigate doses approaching ALARA action levels — this is the program oversight requirement that underpins why passive dosimeters with regular exchange are necessary. EPD requirements in interventional settings: The Joint Commission has specifically addressed the use of EPDs in interventional cardiology and fluoroscopy — requiring real-time dose monitoring for high-volume fluoroscopy performers. This creates the scenario where both an EPD (for TJC real-time requirement) AND a passive badge (for NRC dose-of-record) are simultaneously required. This is the definitive answer to why EPD cannot replace passive dosimeters in Joint Commission-accredited NRC-licensed facilities: both regulatory bodies impose requirements, and neither requirement alone satisfies the other. Encode rad_dosimeter.alarm_capable as 'yes' for EPDs meeting Joint Commission real-time monitoring requirements, and pair with rad_dosimeter.nrc_10_cfr_20_compliant passive badges for complete compliance across both regulatory frameworks.