Production of radioactive phantoms using a standard inkjet printer and the public domain multi-printing code GENIA.

The public domain code GENIA, based on multi-printing method for producing surface sources with appropriate radioactivity, is described. The conventional technique, running on standard inkjet printer with radio-marked ink filling, is improved by repeating elementary printing commands in the same band. Well outlined sources with adjustable radioactivity can be obtained without refilling. The intrinsic limitation of printable radioactivity, depending on the value available at nozzles at printing time, was overcome. In addition the method permits the accurate calibration of the amount of activity released onto the paper.

99MTC [13LEU] bombesin and a new gamma camera, the imaging probe, are able to guide mammotome breast biopsy.

UNLABELLED: A pilot study has been carried out in order to verify the feasibility of scintigraphic driving for breast biopsy. A new high resolution (HR) gamma ray detector, the imaging probe (IP), and 99mTc [13Leu] Bombesin (99mTc BN), have been used to drive a mammotome biopsy needle after having fused radioisotope with digital X-ray images. IP is a mobile, high resolution, miniaturised gamma camera, whose field of view is one inch and whose spatial resolution is 2 mm. 99mTc BN is a new radiotracer derived from the well-known peptide, that has already shown very high sensitivity in detecting breast cancer. PATIENTS AND METHODS: Five patients very suspicious for breast cancer were studied. 185 MBq of 99mTc BN were i.v. injected and dynamic prone scintimammography was performed for 20 minutes with a conventional large field of view gamma camera. IP was matched with the biopsy system and digital X-ray device of a mammotome system, in order to fuse images and to use the mammotome pointer indifferently on X-ray, scintigraphic and fused images. Biopsy samples were counted and weighed: uptake was expressed as counts sec-1 gr-1. Samples were classified into high, intermediate and low uptake. Conventional histological assessment was blindly performed on the samples. RESULTS: All of the patients showed cancer. The T categorisation was T1a for two cancers and T1b for 3. Dynamic prone scintimammography with conventional gamma camera, as well as HR scintigraphy with IP showed spots of 99mTc BN uptake. Maximal mismatch between X-ray lesions and of hot spots imaged with IP before mammotome scintigraphy was 3.4 mm. All the high uptake samples and all but two of the intermediate uptake samples showed cancer, whereas histology found malignant tissue in only 2 out of the 8 low uptake samples. CONCLUSION: 99mTc BN confirms its high sensitivity in detecting breast cancer. IP is able to drive or co-drive breast biopsy when used with appropriate radiopharmaceuticals.

Clinical use of an imaging probe in breast cancer surgery.

AIMS: Portable cameras allow easy transfer of the detector, and thus of radioisotope imaging, to the operating room. In this paper we describe our preliminary experience in radionuclide imaging of breast cancer with a 22.8 x 22.8 mm(2) field-of-view minicamera called "Imaging Probe" (IP). METHODS: Breast cancer detection by IP was performed to guide biopsy, in particular open biopsy, or help fine-needle or core-needle positioning when the main guidance method was ultrasonography or digital radiography. 99mTc Sestamibi (MIBI) was injected 1 h before imaging and biopsy to 14 patients with suspected or known breast cancer. Scintigraphic images were acquired before and after biopsy in each patient. The surgeon was allowed to take into account scintigraphic images as well as previously performed mammograms and ultrasonography. RESULTS: High-resolution IP images were able to guide biopsy toward cancer or toward washout zones of cancer which are thought to be chemoresistant in seven patients out of 10. Four patients in whom IP and MIBI were unable to guide biopsy were found not to have cancer. CONCLUSIONS: Our study confirms the ability of IP to guide breast biopsy even when our minicamera has to be handled manually by trained physicians during surgery.

New localization technique for breast cancer biopsy: mammotome guidance with imaging probe.

AIMS AND BACKGROUND: The "Imaging Probe" (IP) is a small, portable, high-resolution gamma camera to be used in radioguided surgery. The present work discusses a special prototype designed for guiding biopsies. The IP was mounted to a Fischer digital X-ray stereotactic core biopsy system in such a way that biopsy could be guided simultaneously by X-ray stereotaxis and 99mTc-Sestamibi (MIBI) images from IP. METHODS: The IP field of view was 22.8 x 22.8 mm(2), with a spatial resolution of approx. 2.5 mm. We used off-line software for image fusion on a dedicated Pentium III portable PC. It was matched with a Fischer digital X-ray stereotactic biopsy system dedicated to direct the mammotome towards breast opacities. The operator was allowed to slightly correct the direction of the mammotome needle taking into account stereotactic X-ray, scintigraphic and fused images. Biopsy samples were counted by IP before they were sent to the pathologist. RESULTS: High-resolution IP scintigraphy showed substantial, though not exact, matching between MIBI hot spots and X-ray opacities. More than one hot spot was detected even in the smallest (0.6 cm) lesion. Post-biopsy scintigraphy showed absence of significant hot spots in two patients, whereas in the third patient one of the three hot spots was still partially present. All lesions showed cancer on histological examination. CONCLUSIONS: Measurement of radioactivity in biopsy specimens confirmed the heterogeneous distribution of radioactivity within cancers that IP had detected before biopsy.

Radioguided biopsy of osteoid osteoma: usefulness of imaging probe.

AIMS AND BACKGROUND: When removal of osteoid osteoma is performed with open biopsy, the surgeon can be guided by radioactivity of 99mTc-MDP (methylene D- phosphonate) acquired by a probe. MATERIAL AND METHODS: We compared the performance of a commercially available ZnCdTe probe (Neoprobe 2000) and a one-square-inch-field-of-view imaging probe (IP) on two patients undergoing open biopsy for osteoid osteoma. Triphasic bone scintigraphy was performed before operation and Neoprobe as well as IP were used in the operating room by two nuclear physicians. When the surgeon asked for guidance, each nuclear physician had to indicate a precise direction. RESULTS: The surgeon asked for guidance once in the first operation, on a patient with osteoid osteoma of the femur, and four times in the second operation, for osteoid osteoma of the acetabulum. The indications provided by IP were correct 5/5 times, whereas the commercial probe was correct 3/5 times. Both devices were able to assess the surgical radicality. After biopsy, bone samples were divided into high-count and low-count samples. Pathological examination confirmed the presence of osteoid osteoma in high-count samples. CONCLUSIONS: IP has already been used to guide biopsy, but only in breast disease. The present work confirmed its good performance also in orthopedics as a portable mini gamma camera that can be used in the operating room.

Sentinel node detection with imaging probe.

A once-square-inch-field-of-view mini gamma camera, whose first prototype was built by us in 1998 and given the name imaging probe (IP), was initially employed in sentinel lymph node (SLN) detection. This is probably the best way of learning how to use it. In the present work IP was used for SLN localization by a medical team that, after having been trained by the group of nuclear physicians of "La Sapienza" University who designed and first used the detector, used IP at their own hospital to 1) acquire experience for future use during surgery (a cooperative project on IP-radioguided orthopedic surgery is ongoing) and 2) start multicenter trials with IP. The SLN was identified and localized with IP and a non-imaging probe, Neoprobe 2000, in six patients with breast cancer who underwent lymphoscintigraphy for SLN biopsy. The operators who used Neoprobe and IP were blinded to each other's findings and to the results obtained with the large-field-of-view Anger camera that was used for lymphoscintigraphy. The Anger camera, IP and Neoprobe detected seven SLNs in six patients. The mean detection time was 2 mins 6 s (standard deviation (SD) 26 s) with IP, and 2 mins 18 s (SD 47 s) with Neoprobe 2000. The SLN that was most difficult to find was detected in 2 mins 56 s with IP and 3 mins 45 s with Neoprobe. The operators' subjective impression of having detected the SLN was "absolutely sure" for 7/7 nodes with IP and "absolutely sure" for 5/7 nodes with Neoprobe.

Detection of sentinel node in breast cancer: pilot study with the imaging probe.

The commonly used gamma probes are easy to use but also give rough information when employed in radioisotope-guided surgery. When images are required for exact localization, a gamma camera as well as a probe have to be used. Position-sensitive photomultipliers have contemporaneously allowed high-resolution scintigraphy and miniaturization of gamma cameras. We have assembled a miniature gamma camera with a 1-square-inch field of view and an intrinsic resolution of about 1 mm. When the minicamera is collimated with a large-holed, highly sensitive collimator, it acquires a spatial resolution of 3 mm. This prototype has been tested in the detection of difficult-to-image breast cancer sentinel nodes. Five nodes that had not been found with the usual technique of an Anger camera plus conventional probe were checked with the miniature camera that we named imaging probe: it actually is small enough to be used as a probe and large enough to give an image. One of the five nodes was found and imaged. It was small, disease-free, close to the tumor and probably hidden by the Compton halo around the peritumoral injection site. Our pilot study shows that the imaging probe, although still a prototype, has certain advantages over conventional methods when lymph node localization is required during surgery.