The machine lifecycle: procurement to The machine lifecycle: procurement to decommission

decommission

Treatment machines have lifecycles with specifically identified stages. Clear identifica- tion of these stages has provided a structured process to ensure that the performance of the machine is explicitly understood and can be maintained throughout its life. It provides an agreed programme by which both users and manufacturers can deliver machines fit for clinical purpose throughout their life.

Beam stopper Beam line Bending magnets Treatment rooms with isocentric gantry Static beam treatment room Cyclotron Fig. 11.18

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11.11.1

Specification and procurementSpecification and procurement

The first stage is the development of a specification for the machine required and engagement with manufacturers. The specification requires input from all staff groups involved with the machine. It should embody all the legislation and standards applica- ble for the machine and the specific local requirements from the staff groups. These items can take two forms. Either it asks for an unequivocal requirement, e.g. a source to axis distance of 100cm or it asks the manufacturer to describe a feature, e.g. describe the maintenance support for machine breakdown including the response time for assistance and the timescale for the supply of replacement parts. The responses from the manufacturers should be reviewed by the staff groups and it may be that each group’s response can be weighted to give more importance to one groups view. Two aspects are very significant in the choice of a machine: beam matching and transfer of patients. These will tie the procurement choice to the existing equipment if only one machine being sought. Back up and machine transfer are vital to the operation of a busy department and to avoid the interruption of treatment that a different machine manufacturer can be considered only if there are two or more machines being purchased. Architects, builders, computer networking providers and additional equipment suppliers with regard to interfacing should be consulted.

11.11.2

Install, acceptance and commissioningInstall, acceptance and commissioning

The next three stages bring the machine through from delivery to full clinical operation.

11.11.3

InstallationInstallation

During the installation cooperation between the manufacturers installation staff and the local engineers and physicists ensures efficient installation of the machine and that local requirements are met. There can also be beneficial cooperation with the builders during this period.

11.11.4

AcceptanceAcceptance

Following the installation, completion of a formal customer acceptance protocol (CAP) officially marks the handover of the machine from the manufacturer to the purchaser. The CAP documentation and process should be discussed and agreed with the manufacturer before installation. The manufacturer will provide a CAP document and the purchaser may enhance this with additional checks.

11.11.5

CommissioningCommissioning

Once the purchaser has accepted the machine, an extensive set of measurements are undertaken to fully characterize the performance of the machine for clinical use. These include depth dose, tissue phantom ratios, output factors, tray and wedge factors et cetera and also all the data and verification measurements for dose prediction in treatment planning systems. If the machine has been supplied as being matched to an existing machine, these measurements can be simplified to a compari- son with the existing data. So, commissioning the machine concerns gathering all

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the relevant data from which accurate doses can be delivered during the subsequent treatments which the machine will provide. Guidance with regard to the acceptance and commissioning of linacs is provided in a publication by the Institute of Physics and Engineering in Medicine (IPEM) as well as the British Standard for such machines performance BS EN 60976.

11.11.6

_{Quality control and planned maintenanceQuality control and planned maintenance}

The lifetime of a linac is generally accepted to be 10–15 years. During this time the performance of the machine which was identified at commissioning is maintained through a planned maintenance programme and monitored with a quality control programme. Quality control is also required following repairs to the machine in order to ensure performance has been restored. In the Republic of Ireland, prior to there being a planned maintenance programme, the downtime of machines was about 8% due to breakdown. Following the implementation of a programme, even though the time lost to treatment was 8 % including a breakdown of 1.5 %, it was possible to schedule the patients to suit the time lost and so the service was improved. Quality control demonstrates that the required performance is being achieved as well as occasion- ally detecting that the performance has deteriorated below a level at which corrective action should be taken. Planned maintenance and quality control is recognized now in the statutory legislation relating to ionizing radiation, IRR1999 and IRMER2000. It ensures that the computed dose predictions with which an individual patient’s treatment has been planned can be actually delivered.

While quality control programmes confirm that machine performance is maintained, some treatment delivery is now too complex to design a programme which could verify all the combinations of treatment. For example the number of field shapes which can be provided by a multi-leaf collimator (MLC) is limitless as is the case for intensity modulated delivery of a component field for IMRT/VMAT (see Chapter 10). Therefore patient specific quality control is required to ensure that every individual patient treat- ment can be verified. Patient specific quality control is now a component part of quality control of the machine, using fluence measurements to ensure that modulated treatments will be accurately delivered for a specific patient.

Guidance on quality control programmes can be found from the IPEM and for linacs also from the British Standard supplement to BS EN 60976.

11.11.7

Replacement and decommissionReplacement and decommission

Radiation issues in decommissioning is only significant in machines that contain a radioactive source. Manufactur ers are obliged to take into account disposal of the machine at the end of its life and the recycling of components where practicable by a European Directive. From a clinical operations point of view, replacing a machine without service interruption is only possible when an additional treatment room is available to enable the new machine to be installed before the srcinal machine is removed. One difficulty with this can be the level of necessary radiation protection. To achieve this all the treatment rooms need to be designed for the highest energy, which could be too expensive.

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