Impact of proton beam availability on patient treatment schedule in radiation oncology

Abstract

Proton beam therapy offers unique physical properties with potential for reduced toxicity and better patient care. There is an increased interest in radiation oncology centers to acquire proton therapy capabilities. The operation of a proton treatment center is quite different than a photon‐based clinic because of the more complex technology involved, as well as the single proton beam source serving multiple treatment rooms with no backup source available. There is limited published data which investigates metrics that can be used to determine the performance of a proton facility. The purpose of this study is to evaluate performance metrics of Indiana University Cyclotron Operations (IUCO), including availability, mean time between failures, and mean time to repair, and to determine how changes in these metrics impact patient treatments. We utilized a computerized maintenance management system to log all downtime occurrences and servicing operations for the facility. These data were then used to calculate the availability as well as the mean time between failures and mean time to repair. Impact on patient treatments was determined by analyzing delayed and missed treatments, which were recorded in an electronic medical record and database maintained by the therapists. The availability of the IUCO proton beam has been increasing since beginning of operation in 2003 and averaged 96.9% for 2009 through 2011. The mean time between failures and mean time to repair were also determined and correlated with improvements in the maintenance and operating procedures of the facility, as well as environmental factors. It was found that events less than 15 minutes in duration have minimal impact on treatment delays, while events lasting longer than one hour may result in missed treatments. The availability of the proton beam was more closely correlated with delayed than with missed treatments, demonstrating the utility and limitations of the availability metric. In conclusion, we suggest that the availability metric and other performance parameters, such as the mean time between failures and the mean time to repair, should be used in combination with downtime impact on patient treatments in order to adequately evaluate the operational success of a proton therapy facility.PACS number: 87.55.‐x

Treatment interruptions affect biochemical failure rates in prostate cancer patients treated with proton beam therapy: Report from the multi-institutional proton collaborative group registry

“…Recent analyses have found that most maintenance and accelerator shutdowns occur on weekends when major pieces of equipment are turned off and/or being serviced, from power failures, and from inclement weather. Since most radiation treatment centers have multiple linear accelerators, patients can often easily be moved to other units when one becomes non-functional [22] . Conversely, all proton treatment rooms rely on a single cyclotron or synchroton for treatment, so patients cannot be moved from one machine to another.…”

Persistent changes in neuronal structure and synaptic plasticity caused by proton irradiation

“…The capability of gamma irradiation to precipitate long lasting changes in synaptic plasticity that resemble many neurodegenerative conditions suggested such changes might underlie many of the resultant cognitive defects. Based on the increasing presence of hadron therapy for the treatment of CNS and other malignancies (Miller et al 2012), and the paucity of information regarding the effects of such treatments on neuronal structure, we sought to determine if/how exposure to energetic protons might elicit acute and chronic alterations to the anatomical structure of neurons. To facilitate our neurobiologic studies of radiation effects, we selected a transgenic mouse model that expresses enhanced green fluorescent protein (eGFP) under the control of a modified Thy1 promoter that restricts expression to certain subsets of neurons.…”

Quantitative analysis of treatment process time and throughput capacity for spot scanning proton therapy

“…1 Reports on technique developments and the use of PBS proton therapy for various disease sites are plentiful. However, few studies have investigated the efficiency of proton beam therapy, [2][3][4][5][6] including equipment clinical availability (ECA) and treatment process time per patient, defined as the period from the time a patient walks into the treatment room to the time the patient walks out. 4 Schulte provided an overview of proton treatment concepts for ensuring precise proton beam delivery and guaranteeing efficient patient throughput.…”

“…4 Miller et al evaluated the impact of proton beam availability on patient treatment schedules. 5 Aitkenhead et al developed a model for evaluating the throughput capacity of a proton therapy center. 6 However, to the best of our knowledge, no detailed report on the efficiency of an actual spot scanning proton therapy facility has been published.…”