Can hand radiation absorbed dose from radiosynomicronvectomy be high?

Preparing and injecting radiopharmaceuticals containing beta emitting radionuclides, for radiosynovectomy (RS), implies the risk of exceeding the upper limit of skin and hand radiation absorbed dose, of 500 mSv/year to both technologists, who prepare and to doctors, who inject these radiopharmacuticals. A high number of RS treatments per day lack of effective radiation protection devices and skin contamination, increase the skin radiation absorbed dose. Pronounced dosimetric and radiation protection data for radionuclides used for RS, like yttrium-90, erbium-169, rhenium-186, dysprosium-165 and holmium-166, indicate the risk and the rationale for minimizing skin radiation doses to the hands of technologists and to doctors. Hands and skin radiation exposure is mainly due to direct beta radiation from yttrium-90 containing syringes. However skin contamination, may increase this dose independently of the radionuclide used for RS. Using a syringe shield with 5 mm perspex and holding the syringe by forceps, especially for the fixation of the needle to the syringe, beta radiation exposure to the finger tips may be reduced effectively. The use of radiation-resistant gloves reduces beta radiation dose to the skin only slightly, but offers a much better protection than Latex gloves for radioactive contamination. In this article we report measurements performed by us, underlining aspects of the most effective syringe shielding applied for RS. For reducing hands beta radiation exposure during RS the following are proposed: a) To use radiation protection devices, like manipulators and perspex syringe shields and b) Special training of the personnel for the proper handling of doses and for the removal of possible contamination from beta-emitting radionuclides and c) To use beta radiation personal ring dosimeters.     

Mutagenic response of 2.45 GHz radiation exposure on rat brain

Purpose:?To investigate the effect of 2.45?GHz microwave radiation on rat brain of male wistar strain.

Material and methods:?Male rats of wistar strain (35 days old with 130?±?10?g body weight) were selected for this study. Animals were divided into two groups: Sham exposed and experimental. Animals were exposed for 2?h a day for 35 days to 2.45?GHz frequency at 0.34?mW/cm² power density. The whole body specific absorption rate (SAR) was estimated to be 0.11?W/Kg. Exposure took place in a ventilated Plexiglas cage and kept in anechoic chamber in a far field configuration from the horn antenna. After the completion of exposure period, rats were sacrificed and the whole brain tissue was dissected and used for study of double strand DNA (Deoxyribonucleic acid) breaks by micro gel electrophoresis and the statistical analysis was carried out using comet assay (IV-2 version software). Thereafter, antioxidant enzymes and histone kinase estimation was also performed.

Results:?A significant increase was observed in comet head (P?<?0.002), tail length (P?<?0.0002) and in tail movement (P?<?0.0001) in exposed brain cells. An analysis of antioxidant enzymes glutathione peroxidase (P?<?0.005), and superoxide dismutase (P?<?0.006) showed a decrease while an increase in catalase (P?<?0.006) was observed. A significant decrease (P?<?0.023) in histone kinase was also recorded in the exposed group as compared to the control (sham-exposed) ones. One-way analysis of variance (ANOVA) method was adopted for statistical analysis.

Conclusion:?The study concludes that the chronic exposure to these radiations may cause significant damage to brain, which may be an indication of possible tumour promotion (Behari and Paulraj ).     

Unenhanced helical CT for renal colic--is the radiation dose justifiable?

AIM: The purpose of this study was to define and compare the radiation doses to patients undergoing computed tomography (CT) or intravenous urography (IVU) for the investigation of renal colic. METHODS: The IVU dose was calculated from dose area product measurements for 27 abdominal films (AXR) and a review of 30 IVUs performed to investigate renal colic. The effective dose to a patient undergoing CT was calculated using anthropomorphic model data. Fifty patients underwent CT for the investigation of renal colic over a 6-week period. RESULTS: CT following our protocol confers an average effective dose of 4.7 mSv. An IVU to investigate renal colic used 2.5 AXRs. A 3 film IVU gives an average dose of 1.5 mSv. Forty-two CT examinations were abnormal and the findings are described in the text. CONCLUSION: Although unenhanced CT confers diagnostic advantages and avoids the risks of intravenous contrast medium, this should be considered against the increased radiation dose to the patient which in our institution is over three times that of an IVU.     

Science to practice: can fluoroscopic radiation dose be substantially reduced?

McCarville et al have used gray-scale contrast-enhanced low-mechanical-index, and thus non-bubble-destructive, continuous US to quantitate tumor blood flow in mouse tumors engineered to simulate antiangiogenic therapy. They have shown that contrast-enhanced gray-scale US, unlike power or color Doppler US performed without contrast enhancement, is better able to depict and distinguish microvascular flow in subcutaneously implanted mouse tumors possessing different vascular phenotypes.     

Abdominal spiral CT in children: which radiation exposure is required?

We decided to test to what extent dose reduction is possible in abdominal spiral computed tomography (CT) in young children without loss of anatomic diagnostic information. A retrospective study was performed of 30 abdominal CT examinations of children aged 3 months to 7 years. These were divided into two groups: group A with reduced radiation exposure (tube current 50 mA, CT dose index CTDIFDA < or =0.83 mGy) and group B with standard radiation exposure (tube current > or =100 mA, CTDIFDA > or =1.66 mGy). Image quality was assessed using a four-part scale ('excellent', 'good', 'sufficient', 'poor') on visual image impression and visibility of 32 anatomical details. Five experienced radiologists read the CT scans independently who were blinded to the examination parameters. Differences in ranked data were evaluated with Wilcoxon's rank sum test. No difference between groups A and B was observed in visual image impression. Detail visibility was significantly lower in group A, but the differences were limited to right upper quadrant structures (portal vein, common bile duct, pancreatic head, adrenals) and to arterial branches. Significant differences in visibility rated as 'poor' were only found for the hepatic, splenic and renal arteries; all other structures showed no difference between groups A and B. A protocol with reduced radiation exposure (50 mA, CTDIFDA < or =0.83 mGy) allowed the demonstration of most anatomic structures in abdominal spiral CT in young children. For the precise demonstration of small details (e.g. structures of the right upper quadrant), a protocol with standard radiation exposure (> or =100 mAs) was superior.     

Does evening exposure to mobile phone radiation affect subsequent melatonin production?

PURPOSE: To test whether exposure to the emissions from a digital mobile phone handset prior to sleep alters the secretion of melatonin. MATERIALS AND METHODS: In a double-blind cross-over design, 55 adult volunteers were both actively exposed or sham-exposed (in random order on successive Sunday nights) to mobile phone emissions for 30 min (0.25 W average power). Urine collection occurred immediately prior to retiring to bed and on rising the next morning. Melatonin output was estimated from principal metabolite concentrations (6-sulphatoxymelatonin (aMT6s) via radioimmunoassay), urine volumes and creatinine concentrations. RESULTS: Total melatonin metabolite output (concentration x urine volume) was unchanged between the two exposure conditions (active 14.1+/-1.1 microg; sham 14.6+/-1.3 microg). The pre- and post-bedtime outputs considered separately were also not significantly different, although the pre-bedtime value was less for active versus sham exposure. When melatonin metabolite output was estimated from the ratio of aMT6s to creatinine concentrations, the pre-bedtime value was significantly less (p = 0.037) for active compared to sham. Examination of individual responses is suggestive of a small group of 'responders'. CONCLUSIONS: Total nighttime melatonin output is unchanged by mobile phone handset emissions, but there could be an effect on melatonin onset time.     

Complete written/oral information about dose exposure in CT: is it really useful to guarantee the patients’ awareness about radiation risks?

Aims and objectives

According to the European directive 2013/59/Euratom, starting from February 2018, the information relating to patient exposure will be part of computed tomography (CT) reports, but the impact of this information on patients has not been deeply evaluated. Aim of our study was to evaluate patients’ perception of radiation exposure related to routine CT and their understanding after communication of their dose exposure.

Materials and methods

A survey, investigating patient’s knowledge of radiation dose, was given to all adult patients (>?18 years) undergoing a CT examination both before and after CT scan. The first survey was the same for all patients. After CT scan, a second questionnaire was administered (after receiving the CT dose bill report and medical written and/or explanation about ionizing radiation risk). Results of the pre- and post-CT questionnaires responses were compared according to demographics characteristics and among the four post-CT groups.

Results

For some questions, statistically significant differences were found between the two centres. Seventy per cent of the patients answered that the presence of CT parameters in the report is considered useful. Even if not always statistically significant there was a slight increase in awareness of ionizing radiation risk comparing the pre- and post-CT surveys. The group that had both written and oral explanations had a better comprehension of CT dose bill (group III vs. I, p?=?0.002).

Conclusion

The way of communication of ionizing radiation risks did not affect the results of the post-CT survey. Indeed, the interest in the topic did not rise in the post-CT survey in any of the group. Adequate information about ionizing radiation risks provided together with dose exposure information may be useful. However, there is not a standardized better way of communicating information on ionizing radiation risks due to CT.

     

Does selective pleural irradiation of malignant pleural mesothelioma allow radiation dose escalation?

Background

After lung-sparing radiotherapy for malignant pleural mesothelioma (MPM), local failure at sites of previous gross disease represents the dominant form of failure. Our aim is to investigate if selective irradiation of the gross pleural disease only can allow dose escalation.

Materials and methods

In all, 12 consecutive stage I–IV MPM patients (6 left-sided and 6 right-sided) were retrospectively identified and included. A magnetic resonance imaging-based pleural gross tumor volume (GTV) was contoured. Two sets of planning target volumes (PTV) were generated for each patient: (1) a “selective” PTV (S-PTV), originating from a 5-mm isotropic expansion from the GTV and (2) an “elective” PTV (E-PTV), originating from a 5-mm isotropic expansion from the whole ipsilateral pleural space. Two sets of volumetric modulated arc therapy (VMAT) treatment plans were generated: a “selective” pleural irradiation plan (SPI plan) and an “elective” pleural irradiation plan (EPI plan, planned with a simultaneous integrated boost technique [SIB]).

Results

In the SPI plans, the average median dose to the S?PTV was 53.6?Gy (range 41–63.6?Gy). In 4 of 12 patients, it was possible to escalate the dose to the S?PTV to >58?Gy. In the EPI plans, the average median doses to the E?PTV and to the S?PTV were 48.6?Gy (range 38.5–58.7) and 49?Gy (range 38.6–59.5?Gy), respectively. No significant dose escalation was achievable.

Conclusion

The omission of the elective irradiation of the whole ipsilateral pleural space allowed dose escalation from 49?Gy to more than 58?Gy in 4 of 12 chemonaive MPM patients. This strategy may form the basis for nonsurgical radical combined modality treatment of MPM.

     

What are the risks from medical X-rays and other low dose radiation?

The magnitude of the risks from low doses of radiation is one of the central questions in radiological protection. It is particularly relevant when discussing the justification and optimization of diagnostic medical exposures. Medical X-rays can undoubtedly confer substantial benefits in the healthcare of patients, but not without exposing them to effective doses ranging from a few microsieverts to a few tens of millisieverts. Do we have any evidence that these levels of exposure result in significant health risks to patients? The current consensus held by national and international radiological protection organizations is that, for these comparatively low doses, the most appropriate risk model is one in which the risk of radiation-induced cancer and hereditary disease is assumed to increase linearly with increasing radiation dose, with no threshold (the so-called linear no threshold (LNT) model). However, the LNT hypothesis has been challenged both by those who believe that low doses of radiation are more damaging than the hypothesis predicts and by those who believe that they are less harmful, and possibly even beneficial (often referred to as hormesis). This article reviews the evidence for and against both the LNT hypothesis and hormesis, and explains why the general scientific consensus is currently in favour of the LNT model as the most appropriate dose-response relationship for radiation protection purposes at low doses. Finally, the impact of the LNT model on the assessment of the risks from medical X-rays and how this affects the justification and optimization of such exposures is discussed.     

Measurement of radiation exposure to household contacts of patients with Graves’ disease treated with low dose radioactive iodine (131I) on outpatient basis

Background

Patients with Graves’ disease (GD) treated with ¹³¹I represent potential radiation hazard to others including household contacts. Radiation safety is considered an integral part in the protocol of this therapeutic modality. Each center offering this medical service gives specific protective recommendations that should help to ensure compliance with guidelines and radiation precaution regulations for each country, with a final aim of reducing potential harmful radiation exposure to others.

Image quality of ultra-low radiation exposure coronary CT angiography with an effective dose <0.1 mSv using high-pitch spiral acquisition and raw data-based iterative reconstruction

Objectives

We evaluated the potential of prospectively ECG-triggered high-pitch spiral acquisition with low tube voltage and current in combination with iterative reconstruction to achieve coronary CT angiography with sufficient image quality at an effective dose below 0.1 mSv.

Methods

Contrast-enhanced coronary dual source CT angiography (2?×?128?×?0.6 mm, 80 kV, 50 mAs) in prospectively ECG-triggered high-pitch spiral acquisition mode was performed in 21 consecutive individuals (body weight <100 kg, heart rate ≤60/min). Images were reconstructed with raw data-based filtered back projection (FBP) and iterative reconstruction (IR). Image quality was assessed on a 4-point scale (1 = no artefacts, 4 = unevaluable).

Results

Mean effective dose was 0.06?±?0.01 mSv. Image noise was significantly reduced in IR (128.9?±?46.6 vs. 158.2?±?44.7 HU). The mean image quality score was lower for IR (1.9?±?1.1 vs. 2.2?±?1.0, P?<?0.0001). Of 292 coronary segments, 55 in FBP and 40 in IR (P?=?0.12) were graded “unevaluable”. In patients with a body weight ≤75 kg, both in FBP and in IR, the rates of fully evaluable segments were significantly higher in comparison to patients >75 kg.

Conclusions

Coronary CT angiography with an estimated effective dose <0.1 mSv may provide sufficient image quality in selected patients through the combination of high-pitch spiral acquisition and raw data-based iterative reconstruction.

Key Points

? Coronary CT angiography with an estimated effective dose <0.1 mSv is possible. ? Combination of high-pitch spiral acquisition with iterative reconstruction achieves sufficient image quality. ? Diagnostic accuracy remains to be assessed in future trials.     

A clinical example of extreme dose exposure for an implanted cardioverter–defibrillator

Introduction

Considering that the number of malignant diseases in patients over 65 years of age is increasing, it often occurs that patients who carry a cardiac implanted electronic device must undergo radiotherapy. Ionizing radiation can disturb the function of the implantable cardioverter–defibrillator (ICD). As a result of this, an update of the DEGRO/DKG guidelines for radiotherapy of this patient group has been published.

Methods

We report the case of a patient with an ICD and T?lymphoblastic lymphoma with cardiac involvement, who received i.a. a total body irradiation with 8?Gy followed by a consolidating radiotherapy of the pericardium with 14?Gy as well as additional radiotherapy courses after consecutive recurrences. For the purposes of the treatment, the antitachyarrhythmia (ATA) therapy was deactivated and temporarily replaced through a life vest.

Results

According to the current DEGRO guidelines for irradiation of patients with cardiac implanted electronic devices, a categorization of the patient in the “high-risk” group was made. Furthermore, regular telemetric checks of the ICD device were performed before and after treatment. Despite unavailable declaration of the manufacturer regarding the cumulative tolerable dose and DEGRO recommendation for a cumulative dose <2?Gy, the aftercare was unproblematic and normal values were assessed for all relevant ICD parameters, despite a cumulative dose >10?Gy in the device.

Conclusion

This case shows that if the cardiac implanted electronic devices are not directly irradiated und the energy used is reduced to 6 MV, irradiation-induced damage is less likely and can possibly be prevented.