Real-Time Verification of a High-Dose-Rate Iridium 192 Source Position Using a Modified C-Arm Fluoroscope

Nose, Takayuki; Chatani, Masashi; Otani, Yuki; Teshima, Teruki; Kumita, S

doi:10.1016/j.ijrobp.2016.12.005

Cited by 24 publications

(28 citation statements)

References 16 publications

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“…According to reports from the US NRC and ICRP 97 and the Japanese user community, many of the reported events were related to inappropriate channel length, incorrect residence location, incorrect step size, and incorrect prescription volume. Most causes of these events were human errors that were related to treatment planning or commissioning [1,5,10]. Few reports Reports also revealed the incidence of all brachytherapy events to be 0.02-1.6% [6,8,9].…”

Section: Discussionmentioning

confidence: 99%

“…Other studies retrospectively analyzed HDR brachytherapy-related events [3,4] and showed that the commonest event was the wrong applicator measurement and the cause was human errors. In addition, using ICRP and US NRC data reported from 2007 to 2011, Nose et al summarized 64 HDR events for detection timings [5]. Their results revealed that 84% of the events were detected after treatment was administered.…”

Section: Purposementioning

confidence: 99%

“…In December 2013, a misadministration accident for 100 patients with uterine cancer over 7 years was noted in Japan [5]. The cause of this accident was that the input channel length was continuously incorrect; the treatment was performed 3 cm off the tip of the ovoid applicator tip.…”

Section: Purposementioning

confidence: 99%

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First experience of 192Ir source stuck event during high-dose-rate brachytherapy in Japan

Kumagai¹,

Arai²,

Takata³

et al. 2020

jcb

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Purpose: To share the experience of an iridium-192 (192 Ir) source stuck event during high-dose-rate (HDR) brachytherapy for cervical cancer. Material and methods: In 2014, we experienced the first source stuck event in Japan when treating cervical cancer with HDR brachytherapy. The cause of the event was a loose screw in the treatment device that interfered with the gear reeling the source. This event had minimal clinical effects on the patient and staff; however, after the event, we created a normal treatment process and an emergency process. In the emergency processes, each staff member is given an appropriate role. The dose rate distribution calculated by the new Monte Carlo simulation system was used as a reference to create the process. Results: According to the calculated dose rate distribution, the dose rates inside the maze, near the treatment room door, and near the console room were ≅ 10-2 [cGy · h-1 ], 10-3 [cGy · h-1 ], and << 10-3 [cGy · h-1 ], respectively. Based on these findings, in the emergency process, the recorder was evacuated to the console room, and the rescuer waited inside the maze until the radiation source was recovered. This emergency response manual is currently a critical workflow once a year with vendors. Conclusions: We reported our experience of the source stuck event. Details of the event and proposed emergency process will be helpful in managing a patient safety program for other HDR brachytherapy users.

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Section: Discussionmentioning

confidence: 99%

Section: Purposementioning

confidence: 99%

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First experience of 192Ir source stuck event during high-dose-rate brachytherapy in Japan

Kumagai¹,

Arai²,

Takata³

et al. 2020

jcb

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“…Nose et al. reported a real‐time verification method of radioactive source position using modified C‐arm fluoroscopy 15. Although it is ideal to monitor the radioactive source during treatment, radiation regulations may restrict the use of this method.…”

Section: Discussionmentioning

confidence: 99%

“…We used information concerning incidents from the International Commission on Radiological Protection (ICRP) and the Nuclear Regulatory Commission (NRC) summarized by Nose et al 5, 6, 15. We reorganized table 4 from Nose et al.…”

Section: Methodsmentioning

confidence: 99%

High‐dose rate intracavitary brachytherapy pretreatment dwell position verification using a transparent applicator

Otani

Sumida

Nose

et al. 2018

J Applied Clin Med Phys

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PurposeThe major errors in HDR brachytherapy are related to treatment distance, almost all of which are caused by incorrect applicator information. The aim of this study is to propose a quick pretreatment verification method to evaluate channel length and dwell position with a transparent applicator, which, in addition, is suitable as an education tool to assist in the understanding of the applicator structure.MethodsA transparent applicator model was fabricated using a three‐dimensional printer and transparent resin. Its aim is to be a replica of a real gynecological applicator. The pretreatment verification is performed by observing the planned dwell positions of a check cable inside a transparent applicator. A digital camera acquired images and the dwell positions of the radioactive source and check cable were evaluated by comparing them with respect to the theoretical dwell positions marked by the proper x‐ray marker. The potential effectiveness of verification using a transparent applicator was also evaluated using brachytherapy events reported in the literature.ResultsThe transparent applicator closely resembles the real applicator in shape and had an error of less than 0.2 mm. The average dwell position displacement between the radioactive source and check cable was 0.4 mm. The analysis of brachytherapy events showed that channel‐length, dwell‐position, and step‐size errors made up 50% of all events, but affected 64% of all patients.ConclusionsThe transparent applicator model enables a noninvasive, repeatable verification of the channel length and dwell positions to be performed before treatment. This verification has the potential to help prevent common errors in treatment delivery. In addition, the transparent applicator model can be used as a teaching tool to help clinicians understand the operation of the applicator, lowering the risk of events.

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Technical note: Short‐time sequential high‐energy gamma photon imaging using list‐mode data acquisition system for high‐dose‐rate brachytherapy

et al. 2022

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Purpose Measurement of the dwell time and moving speed of a high‐activity iridium‐192 (Ir‐192) source used for high‐dose‐rate (HDR) brachytherapy is important for estimating the precise dose delivery to a tumor. For this purpose, we used a cerium‐doped yttrium aluminum perovskite (YA1O3:YAP(Ce)) gamma camera system, combined with a list‐mode data acquisition system that can acquire short‐time sequential images, and measured the dwell times and moving speeds of the Ir‐192 source. Methods Gamma photon imaging was conducted using the gamma camera in list mode for the Ir‐192 source of HDR brachytherapy with fixed dwell times and positions. The acquired list‐mode images were sorted to millisecond‐order interval time sequential images to evaluate the dwell time at each position. Time count rate curves were derived to calculate the dwell time at each source position and moving speed of the source. Results We could measure the millisecond‐order time sequential images for the Ir‐192 source. The measured times for the preset dwell times of 2 s and 10 s were 1.98 to 2.00 s full width at half maximum (FWHM) and 10.0 s FWHM, respectively. The dwell times at the first dwell position were larger than those at other positions. We also measured the moving speeds of the source after the dwells while moving back to the afterloader and found the speed increased with the distance from the edge of the field of view to the last dwell position. Conclusion We conclude that millisecond‐order time sequential imaging of the Ir‐192 source is possible by using a gamma camera and is useful for evaluating the dwell times and moving speeds of the Ir‐192 source.

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Real-Time Verification of a High-Dose-Rate Iridium 192 Source Position Using a Modified C-Arm Fluoroscope

Cited by 24 publications

References 16 publications

First experience of 192Ir source stuck event during high-dose-rate brachytherapy in Japan

First experience of 192Ir source stuck event during high-dose-rate brachytherapy in Japan

High‐dose rate intracavitary brachytherapy pretreatment dwell position verification using a transparent applicator

Technical note: Short‐time sequential high‐energy gamma photon imaging using list‐mode data acquisition system for high‐dose‐rate brachytherapy

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