Dose Estimates of Occupational Radiation Exposure During Radioguided Surgery of [99mTc]Tc-PSMA-labeled Lymph Nodes in Recurrent Prostate Cancer

Abstract Background and objective[99mTc]Tc-PSMA-based radioguided surgery (TPRS) represents a curative approach for localized relapse of prostate cancer. For its simplified regulatory permission, the radiation protection authorities require a 99mTc activity below the exemption limit of 10 MBq at the time of surgery. Our aim was to determine the optimal amount of radioactivity (OAR) to comply with that limit and to estimate the maximum number of TPRS procedures per year and surgeon without triggering the full monitoring obligations.MethodsIn this retrospective study, a dose rate meter was calibrated using measurements on phantoms and from recently injected (1 min p.i.) patients to determine the activity in the patient from measured dose rates. The effective half-life of [99mTc]Tc-PSMA-I&S in patients was determined from repeated dose rate measurements up to 27 h p.i. to estimate dose parameters of relevance for radiation protection. External exposures of the surgeons were measured with personal dosimeters calibrated in Hp(10). ResultsFrom the first 6 subsequent patients, an effective half-life of 4.15 h was observed. Assuming an operation time 24 h p.i., the OAR was 550 MBq. Operations lasting in average 2 h in a distance of 0.25 m to the patient imply a body dose for surgeons of 4,16 µSv per procedure. Based on these estimates, the surgeon’s Hp(10) is less than 1 mSv per year with up to 241 operations per year. The effective dose for surgeons during the procedure determined with an electronic dosimeter is 4±1 µSv. SummaryAll radiation protection regulations are met with adherence to OAR recommended here without triggering the full monitoring obligations from radiation protection regulations.

Download Full-text

Dose estimates of occupational radiation exposure during radioguided surgery of Tc-99m-PSMA-labeled lymph nodes in recurrent prostate cancer

Nuklearmedizin ◽

10.1055/a-1614-6938 ◽

2021 ◽

Author(s):

Daniel Schmidt ◽

Jirka Grosse ◽

Roman Mayr ◽

Maximilian Burger ◽

Dirk Hellwig

Keyword(s):

Prostate Cancer ◽

Lymph Nodes ◽

Dose Rate ◽

Radiation Protection ◽

Half Life ◽

Operation Time ◽

Radioguided Surgery ◽

Dose Rates ◽

99Mtc Activity ◽

External Exposures

Abstract Aim [99mTc]Tc-PSMA-based radioguided surgery (TPRS) represents a curative approach for localized relapse of prostate cancer. For its simplified regulatory permission, the radiation protection authorities require a 99mTc- activity below the exemption limit of 10 MBq at the time of surgery. Our aim was to determine the optimal amount of radioactivity (OAR) to comply with that limit and to estimate the maximum number of TPRS procedures per year and surgeon without triggering the full monitoring obligations. Methods In this retrospective study, a dose rate meter was calibrated using measurements on phantoms and from recently injected (1 min p. i.) patients to determine the activity in the patient from measured dose rates. The effective half-life of 99mTc-PSMA-I&S in patients was determined from repeated dose rate measurements to estimate dose parameters of relevance for radiation protection. External exposures of the surgeons were measured with personal dosimeters calibrated in Hp(10). The surgeon’s finger dose Hp(0.07) is estimated from radioactivity measured in resected lymph nodes. Potenzial incorporations were estimated for an activity of 10 MBq. Results From the first 6 subsequent patients, an effective half-life of 4.15 h was observed. Assuming an operation time 24 h p. i., the OAR was 550 MBq. Operations lasting in average 2 h in a distance of 0.25 m to the patient imply a body dose for surgeons of 4.16 µSv per procedure. Based on these estimates, the surgeon’s Hp(10) is less than 1 mSv per year with up to 241 operations per year. Hp(0.07) and potential incorporation of activity do not lead to further limitations. Summary All radiation protection regulations are met with adherence to OAR recommended here without triggering the full monitoring obligations from radiation protection regulations.

Download Full-text

Electron and Beta Dose Rates of UO2 Pellet and Fuel Rod

Volume 1: Plant Operations, Maintenance, Engineering, Modifications, Life Cycle and Balance of Plant; Nuclear Fuel and Materials; Radiation Protection and Nuclear Technology Applications ◽

10.1115/icone21-15219 ◽

2013 ◽

Author(s):

Guoqing Zhang ◽

Xuexin Wang ◽

Jiangang Zhang ◽

Dajie Zhuang ◽

Chaoduan Li ◽

...

Keyword(s):

Monte Carlo ◽

Dose Rate ◽

Radiation Protection ◽

High Dose Rate ◽

High Dose ◽

Electron Dose ◽

Dose Rates ◽

Fuel Rod ◽

Calculation Results ◽

Beta Dose

The isotopes of uranium and their daughter nuclides inside the UO2 pellet emit mono-energetic electrons and beta rays, which generate rather high dose rate near the UO2 pellet and could cause exposure to workers. In this work calculations of electron dose rates have been carried out with Monte Carlo codes, MCNPX and Geant4, for a UO2 pellet and a fuel rod. Comparisons between calculations and measurements have been carried out to verify the calculation results. The results could be used to estimate the dose produced by electrons and beta rays, which could be used to make optimization for radiation protection purpose.

Download Full-text

Ion lifetimes in irradiated gaseous HCl

Canadian Journal of Chemistry ◽

10.1139/v67-498 ◽

1967 ◽

Vol 45 (24) ◽

pp. 3079-3082 ◽

Cited By ~ 2

Author(s):

D. A. Armstrong ◽

R. A. Back

Keyword(s):

Dose Rate ◽

Gas Phase ◽

Gamma Rays ◽

Half Life ◽

Field Method ◽

Dose Rates ◽

Phase Combination

An intermittent-field method has been used to measure ion lifetimes in gaseous HCl during irradiation by gamma rays under conditions of pressure, dose rate, and vessel geometry similar to those employed in radiolysis studies. At 23 °C, with HCl pressures from 119 to 660 Torr and dose rates from 5.5 to 86 × 1010 eV cc−1 s−1, the ion half-life ranged from 6 to 30 ms. The dependence on dose rate and pressure strongly indicated that ion neutralization occurred almost entirely in the gas phase. Values of α, the gas-phase combination coefficient, were calculated; at pressures above 246 Torr the value was constant and equal to 3.1 ± 0.3 × 10−6 cc ions−1 s−1. The addition of SF6 had little effect on α, while reducing the temperature to −79 °C increased α to 5.1 × 10−6.

Download Full-text

EVALUATION OF RADIATION DOSE IN DIFFERENT POSITIONS AROUND THE PATIENT TABLE DURING INTERVENTIONAL CARDIOLOGY PROJECTIONS

Radiation Protection Dosimetry ◽

10.1093/rpd/ncz276 ◽

2019 ◽

Vol 188 (2) ◽

pp. 199-204

Author(s):

Y Lahfi ◽

A Ismail

Keyword(s):

Radiation Dose ◽

Radiation Exposure ◽

Dose Rate ◽

Radiation Protection ◽

Interventional Cardiology ◽

X Ray ◽

Dose Rates ◽

Patient Table ◽

The Right

Abstract The aim of the present study was to evaluate the radiation exposure around the patient table as relative to the cardiologist position dose value. The dose rates at eight points presuming staff positions were measured for PA, LAO 30° and RAO 30° radiographic projections, and then normalized to the cardiologist’s position dose-rate value. The results show that in PA and RAO 30° projections, the normalized dose rate was higher by 9–22% at the right side of the table at a distance of 50 cm, while it was higher up to 31% at the left side for the same measured points in the LAO 30°. The differences of normalized dose rates for the both table sides were lower and decreased at farther positions. The obtained results correspond to the recommendations of staff radiation protection in Cath-labs with regards to X-ray tube and detector positions.

Download Full-text

Коэффициент эффективности (DDREF) дозы и мощноcти доз: ненужные, спорные и противоречивые вопросы

Medical Radiology and radiation safety ◽

10.12737/article_58f0b957316ef3.36328519 ◽

2017 ◽

Vol 62 (2) ◽

pp. 13-27

Author(s):

Julio Abel ◽

Julio Abel

Keyword(s):

Radiation Exposure ◽

Dose Rate ◽

Radiation Protection ◽

Radiation Effects ◽

Radiation Risk ◽

Mathematical Formulation ◽

Indirect Evidence ◽

Dose Rates ◽

Radiation Risks ◽

Risk Estimates

Purpose: The aim of the paper is to review the genesis and evolution of the concept termed dose and dose rate effectiveness factor or DDREF, to expose critiques on the concept and to suggest some curse of action on its use. Material and methods: Mainly using the UNSCEAR reporting and ICRP recommendations as the main reference material, the paper describes the evolution (since the 70’s) of the conundrum of inferring radiation risk at low dose and dose-rate. People are usually exposed to radiation at much lower doses and dose rates than those for which quantitative evaluations of incidence of radiation effects are available – a situation that tempted experts to search for a factor relating the epidemiological attribution of effects at high doses and dose-rates with the subjective inference of risk at low doses and dose-rates. The formal introduction and mathematical formulation of the concept by UNSCEAR and ICRP (in the 90’s), is recalled. It is then underlined that the latest UNSCEAR radiation risk estimates did not use a DDREF concept, making it de facto unneeded for purposes of radiation risk attribution. The paper also summarizes the continuous use of the concept for radiation protection purposes and related concerns as well as some current public misunderstandings and apprehension on the DDREF (particularly the aftermath of the Fukushima Dai’ichi NPP accident). It finally discusses epistemological weaknesses of the concept itself. Results: It seems that the DDREF has become superseded by scientific developments and its use has turned out to be unneeded for the purposes of radiation risk estimates. The concept also appears to be arguable for radiation protection purposes, visibly controversial and epistemologically questionable Conclusions: It is suggested that: (i) the use of the DDREF can be definitely abandoned for radiation risk estimates; (ii) while recognizing that radiation protection has different purposes than radiation risk estimation, the discontinuation of using a DDREF for radiation protection might also be considered; (iii) for radiation exposure situations for which there are available epidemiological information that can be scientifically tested (namely which is confirmable and verifiable and therefore falsifiable), radiation risks should continue to be attributed in terms of frequentistic probabilities; and, (iv) for radiation exposure situations for which direct scientific evidence of effects is unavailable or unfeasible to obtain, radiation risks may need to be inferred on the basis of indirect evidence, scientific reasoning and professional judgment aimed at estimating their plausibility in terms of subjective probabilities.

Download Full-text

Radiation exposure around patients after administration of 123I-MIBG

Nuklearmedizin ◽

10.1055/s-0038-1625291 ◽

2002 ◽

Vol 41 (05) ◽

pp. 221-223

Author(s):

S. Ofluoglu ◽

J. Preitfellner ◽

B. J. Fueger ◽

T. Traub ◽

C. Novotny ◽

...

Keyword(s):

Radiation Exposure ◽

Dose Rate ◽

Half Life ◽

Maximum Dose ◽

Radiation Detectors ◽

Mibg Scintigraphy ◽

Dose Limit ◽

Annual Dose ◽

Dose Rates ◽

M 12

SummaryAim: Estimation of the radiation exposure to neighbouring patients, personnel and relatives deriving from patients undergoing 123I-MIBG scintigraphy. Methods: For scintigraphic studies, 16 patients with suspected pheocromocytoma were injected with 340 ± 30 MBq 123I-MIBG. Dose rates were measured at a distance of 0.5 m, 1 m, and 2 m after 10 min, 3 h, 21 h, 45 h, and 68 h using three calibrated portable radiation detectors. The measured values were background corrected. Results: Ten minutes after injection the dose rate was 10.5 µS/h at a distance of 0.5 m, 3.78 µS/h at 1 m, and 0.95 µS/h at 2 m. The effective half-life was estimated to 8.68 ± 0.15 h. The maximum dose in a distance of 1 m for neighbouring patients was 46 µS/h, for personnel in a ward 27 µS/h, and to relatives in a distance of 2 m 12 µS/h. Conclusion: This study demonstrates that the calculated exposure to people around patients after 123I-MIBG injection is well below the maximum permissible annual dose limit of 1 mSv for not professionally exposed persons.

Download Full-text

Delivery of Radiation at the Lowest Dose Rate by a Modern Linear Accelerator is Most Effective in Inhibiting Prostate Cancer Growth

Technology in Cancer Research & Treatment ◽

10.1177/1533033820935525 ◽

2020 ◽

Vol 19 ◽

pp. 153303382093552

Author(s):

Keren Tazat ◽

Oleg Reshetnyak ◽

Natan Shtraus ◽

Ifat Sayag ◽

Nicola J. Mabjeesh ◽

...

Keyword(s):

Prostate Cancer ◽

Tumor Growth ◽

Total Dose ◽

Dose Rate ◽

Linear Accelerator ◽

External Beam Radiotherapy ◽

Xenograft Model ◽

Cancer Growth ◽

Dose Rates ◽

Wide Range

Purpose: External beam radiotherapy is one of the treatment options for organ-confined prostate cancer. A total dose of 70 to 81 Gray (Gy) is given daily (1.8-2.5 Gy/d), with a dose rate of 3 to 6 Gy/min over 28 to 45 treatments during 8 to 9 weeks. We applied the latest technological development in linear accelerators for enabling a wide range of dose rates (from 0.2-21 Gy/min) to test the effect of different delivery dose rates on prostate tumor growth in an animal xenograft model. Materials and Methods: A prostate cancer xenograft model was established in CD1/nude mice by means of PC-3 and CL-1 cells. The animals were radiated by a TrueBeam linear accelerator that delivered 4 dose rates ranging from 0.6 to 14 Gy/min, and reaching a total dose of 20 Gy. The mice were weighed and monitored for tumor development twice weekly. A 2-way analysis of variance was used to compare statistical differences between the groups. Results: Tumor growth was inhibited by radiation at all 4 dose rates in the 20 study mice compared to no radiation (n = 5, controls). The most significant reduction in tumor volumes was observed when the same dose of radiation was delivered at a rate of 0.6 Gy/min ( P < .01). The animals’ weights were not affected by any dose rate. Conclusions: Delivery of radiation with a TrueBeam linear accelerator at the lowest possible rate was most effective in prostate cancer growth inhibition and might be considered a preferential treatment mode for localized prostate cancer.

Download Full-text

Evidence That Lifelong Low Dose Rates of Ionizing Radiation Increase Lifespan in Long- and Short-Lived Dogs

Dose-Response ◽

10.1177/1559325817692903 ◽

2017 ◽

Vol 15 (1) ◽

pp. 155932581769290 ◽

Cited By ~ 11

Author(s):

Jerry M. Cuttler ◽

Ludwig E. Feinendegen ◽

Yehoshua Socol

Keyword(s):

Ionizing Radiation ◽

Dose Rate ◽

Radiation Protection ◽

Large Scale ◽

Low Dose ◽

Health Impact ◽

The Other ◽

Protection Policy ◽

Dose Rates ◽

Cancer Induction

After the 1956 radiation scare to stop weapons testing, studies focused on cancer induction by low-level radiation. Concern has shifted to protecting “radiation-sensitive individuals.” Since longevity is a measure of health impact, this analysis reexamined data to compare the effect of dose rate on the lifespans of short-lived (5% and 10% mortality) dogs and on the lifespans of dogs at 50% mortality. The data came from 2 large-scale studies. One exposed 10 groups to different γ dose rates; the other exposed 8 groups to different lung burdens of plutonium. Reexamination indicated that normalized lifespans increased more for short-lived dogs than for average dogs, when radiation was moderately above background. This was apparent by interpolating between the lifespans of nonirradiated dogs and exposed dogs. The optimum lifespan increase appeared at 50 mGy/y. The threshold for harm (decreased lifespan) was 700 mGy/y for 50% mortality dogs and 1100 mGy/y for short-lived dogs. For inhaled α-emitting particulates, longevity was remarkably increased for short-lived dogs below the threshold for harm. Short-lived dogs seem more radiosensitive than average dogs and they benefit more from low radiation. If dogs model humans, this evidence would support a change to radiation protection policy. Maintaining exposures “as low as reasonably achievable” (ALARA) appears questionable.

Download Full-text

Effective doses to staff and dose rates emitted from patients undergoing positron emission tomography utilizing 18F- Fluorodeoxglucose

Radiography Open ◽

10.7577/radopen.1526 ◽

2015 ◽

Vol 2 (1) ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

Carl Petter Skaar Kulseng ◽

Jon Christoffer Sandstrøm

Keyword(s):

Effective Dose ◽

Dose Rate ◽

The Body ◽

Whole Body ◽

Average Dose ◽

Body Parts ◽

Dose Rates ◽

Effective Doses ◽

Occupational Radiation ◽

Different Parts

IntroductionThe purpose of this two--folded quantitative study was to determine the radiation doses received by staff during 2014 at the PET--department at St. Olavs Hospital in Trondheim, Norway. Although studies show that the doses received by staff performing such examinations are far beneath the limits set by regulation, there was a need to determine how much radiation the staff at this clinic actually was exposed to. We investigated in detail both dose rates emitted by 18 F from different parts of the body to the surroundings along with effective doses to staff during 2014.MethodPart one - Dose rates from 20 patients undergoing FDG-PET/CT--scans were measured with dosimeter RadEye B20 (Thermo Scientific, USA) from five measuring points at three different stages of a standard whole body PET-scan utilizing 18 F-FDG.Part two - Effective doses to five radiographers and four bioengineers were registered daily during 2014. The effective dose measurements were done daily by the staff with personal dosimeter RadEye EPD MK2+ (Thermo Scientific, USA). The dosimeter was worn at chest level. The automatic injector Medrad Intego (Bayer, Germany) administrate the radioactive doses.ResultsPart one - Dose rates emitted from different parts of patients show significant differences. The highest dose rate was measured from the head and sternum of the patients. The knees emit the least dose rate of all body parts and was considerably lower from one meterdistance.Part two - The average effective doses were far below the recommended limits for occupational radiation. The total average effective dose per member of staff was 0.13 mSv in 2014 and the daily average dose was 4.91 μSv/day.ConclusionPart one - 18 F-FDG showed irregular distribution in the body, the lowest dose rates originated from the lower extremities and reflects the metabolism of glucose in the body at rest.Part two - We found significant differences between staff working with both CT and the radioisotope injection compared to the staff working solely with one of these tasks. Nevertheless, all effective- doses were safely within the guideline limits for occupational radiation.

Download Full-text