Thesis

52 Part I Chapter 2 Table 5. Sources of error • Injection artifacts. • Imaging too early after injection, before the radiopharmaceutical has been optimally cleared from soft tissues. • Greater than necessary collimator to patient distance. • Patient movement. • Pubic or sacral lesions obscured by superposition of bladder activity. • Urine contamination or a urinary diversion reservoir. • Changing bladder activity during SPECT of the pelvic region. • Purely lytic lesions with decreased or absent tracer uptake. • Prosthetic implants, radiographic contrast materials or other attenuating artifacts which may obscure normal structures. • Homogeneously increased bony activity (e.g. ‘superscan’). • Renal failure. • Restraint artifacts caused by soft tissue compression. • Significant findings outside the area of interest may be missed if a limited study is performed. • Prior administration of a higher energy radionuclide, or of a preceding examinationwith another 99mTc radiopharmaceutical that accumulates in an organ that could obscure or confound skeletal activity. • Radiopharmaceutical degradation Some bone lesions may be purely or predominantly lytic and barely visible on planar bone scintigraphy when they are small (<2 cm): multiple myeloma, infarction, osteonecrosis, hemangioma, or lytic bone metastases. These artifacts and sources of error can be intercepted with an additional SPECT/CT acquisition. Documentation/reporting Clinical context The nuclear medicine physician should record a brief summary of the reason for the examination, the clinical problem, the medical or surgical history, all relevant laboratory results and radiological findings, and the treatments targeting or interfering with the osteoarticular system. Procedure Technical information should include the international non-proprietary name (INN) of the radiolabelled bisphosphonate, the injected activity in MBq, the site and time of injection, the time of image acquisition, the scanning protocol used (early phase, late phase, SPECT/CT images), the different image acquisitions, and the dose length product (DLP) and computed tomography dose index (CTDI) if SPECT/CT is performed. Optionally, the model and installation date of the camera can be stated.

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