Young Adult Populations Face Yet Another Barrier to Care With Insurers: Limited Access to Proton Therapy.

PURPOSE: Young patients, including pediatric, adolescent, and young adult (YA) patients, are most likely to benefit from the reduced integral dose of proton beam radiation therapy (PBT) resulting in fewer late toxicities and secondary malignancies. This study sought to examine insurance approval and appeal outcomes for PBT among YA patients compared with pediatric patients at a large-volume proton therapy center. METHODS AND MATERIALS: We performed a cross-sectional cohort study of 284 consecutive patients aged 0 to 39 years for whom PBT was recommended in 2018 through 2019. Pediatric patients were defined as aged 0 to 18 years and YA patients 19 to 39 years. Rates of approval, denials, and decision timelines were calculated. Tumor type and location were also evaluated as factors that may influence insurance decisions. RESULTS: A total of 207 patients (73%) were approved for PBT at initial request. YA patients (n = 68/143, 48%) were significantly less likely to receive initial approval compared with pediatric patients (n = 139/141; 99%) (P < .001). Even after 47% (n = 35 of 75) of the PBT denials for YA patients were overturned, YAs had a significantly lower final PBT approval (72% vs pediatric 99%; P < .001). The median wait time was also significantly longer for YA patients (median, 8 days; interquartile range [IQR] 3-17 vs median, 2 days; IQR, 0-6; P < .001). In those patients requiring an appeal, the median wait time was 16 days (IQR, 9-25). CONCLUSION: Given the decades of survivorship of YA patients, PBT is an important tool to reduce late toxicities and secondary malignancies. Compared with pediatric patients, YA patients are significantly less likely to receive insurance approval for PBT. Insurance denials and subsequent appeal requests result in significant delays for YA patients. Insurers need to re-examine their policies to include expedited decisions and appeals and removal of arbitrary age cutoffs so that YA patients can gain easier access to PBT. Furthermore, consensus guidelines encouraging greater PBT access for YA may be warranted from both medical societies and/or AYA experts.

Assessment of radiation leakage from treatment applicator of Siemens Primus Plus and Siemens Artiste linear accelerators.

AIM: The purpose of this study is to measure radiation leakage of Siemens Primus Plus and Siemens Artiste linear accelerators in electron mode and to compare the leakage level with that recommended by the International Electrotechnical Commission (IEC) standard. MATERIALS AND METHODS: In this assessment, Siemens Primus Plus linear accelerator with 10 cm × 10 cm, 15 cm × 15 cm, and 25 cm × 25 cm applicators was used. The radiation leakage in lateral and vertical directions was measured for Siemens Primus Plus and Siemens Artiste linear accelerators. RESULTS: Data derived from radiation leakage measurement for Siemens Primus Plus and Siemens Artiste linear accelerators in lateral direction from the field edge and in vertical direction from the applicator were reported. The radiation leakage data were then compared with the IEC standard to evaluate in-air field leakage. CONCLUSION: Comparing the radiation leakage level from fields with the IEC standard for two applicators, the maximum that was occurred for 12 MeV electron beam and applicator size of 10 cm × 10 cm in Siemens Artiste linear accelerator was 2.3%, which is less than the IEC's recommended limit of 10%. It is concluded that the leakage amount is much less than the specified limit and that both of the linear accelerators have high level of safety. Considering the measurement stage, it also needs to be noted that the beam angle affected the radiation leakage level from field edge, and in 25° angle, it is higher than in 0° angle. Comparing radiation leakage from the right side of the field for the two linear accelerators, the amount of leakage for Siemens Primus Plus linear accelerator is more than Siemens Artiste linear accelerator.

NON-TARGETED EFFECTS LEAD TO A PARIDIGM SHIFT IN RISK ASSESSMENT FOR A MISSION TO THE EARTH'S MOON OR MARTIAN MOON PHOBOS.

Cancer risk is an important limitation for galactic cosmic ray (GCR) exposures, which consist of a wide-energy range of protons, heavy ions and secondary radiation produced in shielding and tissues. Many studies suggest non-targeted effects (NTEs) occur for low doses of high-linear energy transfer (LET) radiation, leading to deviation from the linear dose response model used in radiation protection. We investigate corrections to quality factors (QF) for NTEs, which are used in predictions of fatal cancer risks for exploration missions. Prediction of fatal cancer risks for missions to the Martian moon, Phobos of 500-d and the Earth's moon of 365-d for average solar minimum condition show increases of 2- to 4-fold higher in the NTE model compared with the conventional model. Limitations in estimating uncertainties in NTE model parameters due to sparse radiobiology data at low doses are discussed.

Low dose radiation, inflammation, cancer and chemoprevention.

PURPOSE: Recently, new studies have brought to light the potential risks of low dose radiation (LDR) in cancer. In this review, we discuss in detail the detrimental effects of LDR in some model organisms and animal models, as well as potential risks to human beings from some routine medical screening procedures. Furthermore, cellular mechanisms by which LDR exerts its negative effects like endoplasmic reticulum stress, epigenetic changes and microRNAs are also reviewed. A few studies are discussed that have reported some benefits of LDR through changes in energy metabolism. Lastly, we focus on breast cancer, one of the predominant forms of cancer potentially affected by LDR and some of the benefits of n-3 polyunsaturated fatty acids (PUFA) as dietary compounds that offer protection against radiation effects on cancer cells and cancer progression. CONCLUSIONS: Overall, LDR exerts mainly damaging effects through diverse cell and molecular mechanisms, with a few beneficial effects reported. In some cancers, surrounding adipose tissue of the breast may contribute to obesity-related cancer. Further, preclinical data suggest that anti-inflammatory dietary compounds such as PUFA and other dietary interventions may protect against radiation effects on cancer cells and cancer progression.

The Current State of CT Dose Management Across Radiology: Well Intentioned but Not Universally Well Executed.

OBJECTIVE: Recent well-publicized sentinel events have resulted in an appropriately heightened awareness of CT dose. Concern also exists regarding the potential of CT dose increasing the risk of cancer. Several professional societies, governmental and accreditation agencies, and CT vendors have responded to these concerns with campaigns, mandatory standards, and software enhancements. The objective of this article is to review such CT dose management efforts. CONCLUSION: Although CT dose awareness campaigns, mandatory standards, and software enhancements are well intentioned, their implementation is often suboptimal.

Peripheral equivalent neutron dose model implementation for radiotherapy patients.

PURPOSE: Neutron peripheral contamination in high-energy radiotherapy implies an increase of secondary radiation-induced cancer risk. Although peripheral neutron dose (PND) has been evaluated in organs, few studies have been performed regarding patient size. This work aims to improve an existing methodology for adult patient PND estimations to generalize it to young and children, for its implementation in treatment planning systems (TPS). METHODS: As a first step, we aimed to generalize the previous model to be usable with any thermal neutron detector. Then, taking into account total neutron spectra and dose-to-point thermal neutron fluence measurements for three phantom sizes (adult, teen and child) and two common treatment locations (H&N and abdomen), the new model was proposed. It represents an upgraded parameterization and extension of the existing one, including patient anatomy. Finally, comparison between estimations and measurements, as well as validation against the original model, was carried out for 510 measured patients. RESULTS: Concordance found between experimental and theoretical estimations makes us confident about later implementation in treatment planning systems. Comparison among the previous and upgraded models shows no significant differences for the adult case. However, an important underestimation (34.1% on average) can be observed regarding child case for the original one. CONCLUSIONS: An improved generalization of an existing PND model, considering patient anatomy has been validated and used in real patients. The final methodology is easily implementable in clinical routine and TPS thanks to the ready availability of input parameters (patient height and weight, high-energy MU and facility characterization).

Neutron dose in and out of 18MV photon fields.

In radiation therapy, neutron contamination is an undesirable side effect of using high energy photons to treat patients. Neutron contamination requires adjustments to the shielding requirements of the linear accelerator vault and contributes to the risk of secondary malignancies in patients by delivering dose outside of the primary treatment field. Using MCNPX, an established Monte Carlo code, manufacturer blueprints, and the most up to date ICRP neutron dose conversion factors, the neutron spectra, neutron/photon dose ratio, and the neutron capture gamma ray dose were calculated at different depths and off axis distances in a tissue equivalent phantom. Results demonstrated that the neutron spectra and dose are dependent on field size, depth in the phantom, and off-axis distance. Simulations showed that because of the low neutron absorption cross section of the linear accelerator head materials, the contribution to overall patient dose from neutrons can be up to 1000 times the photon dose out of the treatment field and is also dependent on field size and depth. Beyond 45cm off-axis, the dependence of the neutron dose on field size is minimal. Neutron capture gamma ray dose is also field size dependent and is at a maximum at a depth of about 7cm. It is important to remember that when treating with high energy photons, the dose from contamination neutrons must be considered as it is much greater than the photon dose.

The First Meeting of the WHO Guideline Development Group for the Revision of the WHO 1999 Guidelines for Iodine Thyroid Blocking.

The meeting held in May 2014 in Würzburg, Germany, discussed the scope of the revision of the 1999 WHO guidelines for iodine thyroid blocking (ITB) by following the WHO handbook for guideline development. This article describes the process and methods of developing the revised, evidence-based WHO guidelines for ITB following nuclear and radiological accidents, the results of the kick-off meeting as well as further steps taken to complete the revision.

Mammographic screening in BRCA1 mutation carriers postponed until age 40: Evaluation of benefits, costs and radiation risks using models.

PURPOSE: BRCA1 mutation carriers are offered screening with magnetic resonance imaging (MRI) and mammography. The aim of this study was to weigh benefits and risks of postponing mammographic screening until age 40. METHODS: With the MISCAN microsimulation model two screening protocols were evaluated: 1) the current Dutch guidelines: annual MRI from age 25-60, annual mammography from age 30-60, and biennial mammography in the nationwide program from age 60-74, and 2) the modified protocol: with annual mammography postponed until age 40. A cost-effectiveness analysis was performed. The risks of radiation-induced breast cancer mortality were estimated with absolute and relative exposure-risk models of the 7th Biological Effects of Ionising Radiation Committee. RESULTS: Current screening guidelines prevent 13,139 breast cancer deaths per 100,000 BRCA1 mutation carriers. Postponing mammography until age 40 would increase breast cancer deaths by 23 (0.17%), but would also reduce radiation-induced breast cancer deaths by 15 or 105 using the absolute and relative risk model respectively per 100,000 women screened. The estimated net effect is an increase of eight or a reduction of 82 breast cancer deaths per 100,000 women screened (depending on the risk model used). The incremental cost of mammograms between age 30-39 is €272,900 per life year gained. CONCLUSIONS: The modified protocol may be slightly less effective or even better than the current guidelines. The high cost-savings justify a possible small loss of effectiveness.

Examining the differences in current regulatory processes for sunscreens and proposed safety assessment paradigm.

Skin cancers including malignant melanoma which are due to UV radiation constitute a serious public health problem. Recent studies have confirmed the importance of UVA radiation in the pathogenesis of skin cancer, as well as the protective effects of broad-spectrum sunscreen use. Barriers for effective protection of the US public include the lack of effective UV filters, especially in the UVA spectrum. The major reason for the paucity of UVA-effective filters in the US is due primarily to the FDA's reluctance to approve agents which have already been on the market in Europe and elsewhere in the world for more than a decade. The underlying reasons for these discrepancies in new sunscreen approval success between the US and abroad are complex, and include factors such as that the FDA considers UV filters as drugs, whereas they are regulated as cosmetics elsewhere. FDA has not as yet developed a consistent approach for the approval of new UV filters. We provide a paradigm for both non-clinical testing and human safety testing which includes parameters for a human maximum use test (MUsT) that is based upon both ethical and scientific concepts. These suggestions could form the basis of future regulatory guidelines for rational testing thus allowing us to reach the consensus goal of more efficient and timely approval of much-needed UV filters to provide protection for the US public.

Effective Radiation Dose in a Skeletal Survey Performed for Suspected Child Abuse.

Effective dose of a skeletal survey in infants using digital radiography was estimated to be 0.2 mSv using Monte Carlo simulation. Radiation risk from this procedure is, therefore, low. Radiation concern should not be an overriding factor when deciding whether skeletal survey is needed in cases of possible physical abuse.

Future of Radiation Protection Regulations.

THERE IS considerable disagreement in the scientific community regarding the carcinogenicity of low-dose radiation (LDR), with publications supporting opposing points of view. However, major flaws have been identified in many of the publications claiming increased cancer risk from LDR. The data generally recognized as the most important for assessing radiation effects in humans, the atomic bomb survivor data, are often cited to raise LDR cancer concerns. However, these data no longer support the linear no-threshold (LNT) model after the 2012 update but are consistent with radiation hormesis. Thus, a resolution of the controversy regarding the carcinogenicity of LDR appears to be imminent, with the rejection of the LNT model and acceptance of radiation hormesis. Hence, for setting radiation protection regulations, an alternative approach to the present one based on the LNT model is needed. One approach would be to determine the threshold dose for the carcinogenic effect of radiation from existing data and establish regulations to ensure radiation doses are kept well below the threshold dose. This can be done by setting dose guidelines specifying safe levels of radiation doses, with the requirement that these safe levels, referred to as guidance levels, not be exceeded significantly. Using this approach, a dose guidance level of 10 cGy for acute radiation exposures and 10 cGy y for exposures over extended periods of time are recommended. The concept of keeping doses as low as reasonably achievable, known as ALARA, would no longer be required for low-level radiation exposures not expected to exceed the dose guidance levels significantly. These regulations would facilitate studies using LDR for prevention and treatment of diseases. Results from such studies would be helpful in refining dose guidance levels. The dose guidance levels would be the same for the public and radiation workers to ensure everyone's safety.

Prospective Assessment of the Oncogenic Risk to Patients From Fluoroscopy During Trauma Surgery.

OBJECTIVE: Concern about radiation exposure during surgery has focused on surgeon exposure. However, the patient receives exposure that is more direct and, in surgery about the pelvis and hip, internal pelvic nonskeletal organs often cannot be shielded without obscuring the region of surgical interest. The purpose of this study was to prospectively evaluate patients' radiation exposure during fracture surgery of the acetabulum, pelvic ring, and femur to calculate future cancer incidence (CI). DESIGN: Prospective descriptive cohort. SETTING: Level-1 trauma center. PATIENTS/PARTICIPANTS: One hundred eight patients with acetabulum, pelvic, or femur fractures requiring operative repair were prospectively enrolled. INTERVENTION: Dosimeters were placed in locations determined for each surgery type by a medical physicist. MAIN OUTCOME MEASUREMENTS: Demographics, operative records, and average x-ray emission energy were recorded. Effective dose, specific organ doses, and lifetime CI for a 30-year-old patient were calculated. RESULTS: Diagnoses included 27 acetabular fractures, 30 intertrochanteric femur fractures, 26 femoral shafts, and 25 pelvic ring injuries. Patients with pelvic ring injuries received the highest effective dose at 0.91 ± 0.74 mSv. The average lifetime increase in CI, for any cancer type, after pelvic ring fixation is 0.0097% for females and 0.0062% for males. The greatest mean single-organ dose to the ovaries (3.82 ± 3.34 mGy) occurred during pelvic ring surgery, correlating to an increased ovarian cancer risk of 0.0013%. The greatest mean single-organ dose to the prostate (6.81 ± 5.91 mSv) also occurred during pelvic surgery, correlating to increased prostate cancer risk of 0.0024%. CONCLUSIONS: Fracture surgery to the pelvis and femur is exceptionally fluoroscopy-dependent; however, the radiation exposure incurred represents a relatively small increased risk of future cancer development in patients. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

CT Radiation: Key Concepts for Gentle and Wise Use.

Use of computed tomography (CT) in medicine comes with the responsibility of its appropriate (wise) and safe (gentle) application to obtain required diagnostic information with the lowest possible dose of radiation. CT provides useful information that may not be available with other imaging modalities in many clinical situations in children and adults. Inappropriate or excessive use of CT should be avoided, especially if required information can be obtained in an accurate and time-efficient manner with other modalities that require a lower radiation dose, or non-radiation-based imaging modalities such as ultrasonography and magnetic resonance imaging. In addition to appropriate use of CT, the radiology community also must monitor scanning practices and protocols. When appropriate, high-contrast regions and lesions should be scanned with reduced dose, but overly zealous dose reduction should be avoided for assessment of low-contrast lesions. Patients' cross-sectional body size should be taken into account to deliver lower radiation dose to smaller patients and children. Wise use of CT scanning with gentle application of radiation dose can help maximize the diagnostic value of CT, as well as address concerns about potential risks of radiation. In this article, key concepts in CT radiation dose are reviewed, including CT dose descriptors; radiation doses from CT procedures; and factors and technologies that affect radiation dose and image quality, including their use in creating dose-saving protocols. Also discussed are the contributions of radiation awareness campaigns such as the Image Gently and Image Wisely campaigns and the American College of Radiology Dose Index Registry initiatives.

The Growing Public Health Challenges of Exposure to Ultraviolet Radiation From Use of Indoor Tanning Devices in the United States.

Ultraviolet radiation is recognized as a human carcinogen by the International Agency for Research on Cancer, the world's authority on cancer research. In particular, exposure to ultraviolet radiation can lead to melanoma of the skin, which is the deadliest form of skin cancer in the United States. Yet despite the significant public health burden that is associated with skin cancer in the United States, each year over a million Americans engage in indoor tanning where exposure to artificial ultraviolet radiation occurs. In this article, we argue for an immediate ban on the use of commercial indoor tanning by minors and, based on international precedents, the phasing out of all commercial tanning operations in the United States. We consider the use of indoor tanning devices in the United States, epidemiological data on indoor tanning devices and cancer, regulation of tanning devices, and scientific evidence for increased government intervention.

Dose reduction in chest CT examination.

Computed tomography (CT) examinations involve relatively high doses to patients. The objectives of this study were to optimise the radiation dose for patient during CT chest scan and to estimate the lifetime cancer risk. A total of 50 patients were studied: control group (A) (38 patients) and optimisation group (B) (12 patients). The optimisation protocol was based on CT pitch increment and lowering tube current. The mean volume CT dose index (CTDI vol) was 21.17 mGy and dose length product (DLP) was 839.0 mGy cm for Group A, and CTDI vol was 8.3 mGy and DLP was 339.7 for Group B. The overall cancer risk was estimated to be 8.0 and 3.0 cancer incidence per million for Groups A and B, respectively. The patient dose optimisation during CT chest was investigated. Lowering tube current and pitch increment achieved a radiation dose reduction of up to 60 % without compromising the diagnostic findings.

Youth indoor tanning and skin cancer prevention: lessons from tobacco control.

Youth use of ultraviolet-emitting indoor tanning beds represents a present and emerging public health crisis. Nearly 30% of white female high school students report tanning indoors, and a quarter of high school tanners have used a tanning bed more than 20 times in the past year. Despite the significant health risks of tanning beds, including potentially deadly melanoma and eye problems, limited actions have been taken in the U.S. to protect youth. Tobacco control policies and campaigns, which have sharply reduced youth smoking, may provide a useful framework to control indoor tanning among young people. This article describes several evidence-based tobacco control strategies with potential applicability to indoor tanning within the context of the U.S. Further, current tobacco control policies and current indoor tanning policies in the U.S. are compared, and recommendations on how to curtail youth indoor tanning are discussed.

γ-H2AX foci as in vivo effect biomarker in children emphasize the importance to minimize x-ray doses in paediatric CT imaging.

OBJECTIVES: Investigation of DNA damage induced by CT x-rays in paediatric patients versus patient dose in a multicentre setting. METHODS: From 51 paediatric patients (median age, 3.8 years) who underwent an abdomen or chest CT examination in one of the five participating radiology departments, blood samples were taken before and shortly after the examination. DNA damage was estimated by scoring γ-H2AX foci in peripheral blood T lymphocytes. Patient-specific organ and tissue doses were calculated with a validated Monte Carlo program. Individual lifetime attributable risks (LAR) for cancer incidence and mortality were estimated according to the BEIR VII risk models. RESULTS: Despite the low CT doses, a median increase of 0.13 γ-H2AX foci/cell was observed. Plotting the induced γ-H2AX foci versus blood dose indicated a low-dose hypersensitivity, supported also by an in vitro dose-response study. Differences in dose levels between radiology centres were reflected in differences in DNA damage. LAR of cancer mortality for the paediatric chest CT and abdomen CT cohort was 0.08 and 0.13 ‰ respectively. CONCLUSION: CT x-rays induce DNA damage in paediatric patients even at low doses and the level of DNA damage is reduced by application of more effective CT dose reduction techniques and paediatric protocols. .