There are eight dual head SPECT/CT systems in the Department of Radiology from each of the major vendors including Siemens Symbia T16s, GE Discovery NM/CT 670, and Philips Precedence. The SPECT/CT systems are routinely used for imaging patients to facilitate diagnosis, therapy, and research. All SPECT/CT have a range of collimators, including parallel hole collimators rated for a range of energies and pinhole collimators. Image reconstruction capability includes iterative reconstruction with corrections for scatter and attenuation, as well as collimator-detector response compensation from the three major commercial manufacturers. In addition to the conventional modes of gamma camera acquisition, capability exists for list-mode acquisition and off-line image reconstruction.

PET imaging equipment includes three PET/CT scanners: a Siemens Biograph mCT, a Siemens Biograph Vision, and a GE Discovery VCT(RX). Among the three, the Biograph Vision is dedicated for research uses. The PET/CT systems have either 128 and 64 slice CT capability that can be used for diagnostic CT protocols as well as low-dose CT for PET attenuation correction and localization. The PET systems support a range of flexible acquisition modes including list-mode, dynamic and both ECG and respiratory gating.

The Radiological Physics Division maintains a high-performance computer cluster that consists of 40 rack mounted compute nodes. The systems all have either 2 or 4 processors and from 1 to 16 cores per processor with speeds ranging from 2 .0 to 2.3 GHz. There are a total of >1250 processor cores. Memory ranges from 8 to 512 GB per system with a total of 2.3 TB of memory. All the systems are 64 bit and run CentOS Linux. The systems are connected using GB Ethernet and stackable switches; some systems are connected using channel bonding to increase throughput. In addition to the standard compute nodes, the cluster also contains several GPU’s including an NVIDIA Quadro P5000, an NVIDIA Tesla C1060 with 4 GB of memory and 240 streaming processor cores, and 4 Tesla K40m GPUs each having 12 GB of RAM and 2880 processor cores. A recently purchased Microway workstation with dual XEON CPU, 512 GM memory, and a NVDIA H100 GPU with 80 GM of memory, was installed in the cluster.

We deliver external beam radiation therapy using nine state-of-the-art medical linear accelerators and one Cyberknife to realize conventional 3D conformal radiation therapy, intensity modulated radiation therapy, stereotactic radiosurgery, and stereotactic body radiation therapy. Novel image guidance techniques using x-ray imaging, cone beam CT, surface imaging are routinely used to ensure treatment accuracy and patient safety. Two MR simulators and five CT simulators are available to perform simulations for treatment planning.

The Johns Hopkins Proton Therapy Center is one of the largest and most sophisticated proton therapy treatment centers in the U.S. Our 80,000-square-foot proton center contains three specially equipped treatment rooms to deliver proton therapy using a synchrotron accelerator from Hitachi, plus an additional space dedicated to research.

Brachytherapy at Johns Hopkins is often used in conjunction with external beam therapy for a comprehensive approach to cancer treatment. It's particularly beneficial for treating cancers such as those of the prostate, cervix, uterus, vagina, breast, eye, and certain head and neck cancers. The treatment can be either temporary or permanent, with the implants sometimes remaining in the body permanently and gradually losing radioactivity. Johns Hopkins uses advanced techniques including real-time X-ray and MR imaging to enhance the precision of seed placement during procedures, improving treatment efficacy and safety.

Radionuclide therapy is a sophisticated method used in the diagnosis and treatment of various diseases, notably cancers. This therapy involves the administration of radioactive substances, known as radionuclides, which are selectively absorbed by certain tissues or organs. The emitted radiation from these radionuclides helps in both diagnosing and treating diseases by targeting specific cells. Our work includes patient-specific dosimetry and mathematical modeling, which are critical for optimizing treatment efficacy and safety. The efforts are particularly geared towards metastatic cancer treatments using alpha-emitter therapy.

Experimental Irradiators Share Resource was responsible for the development and advancement of an image-guided orthovoltage small-animal radiation research platform (SARRP) and the investigators recently developed molecular optical (bioluminescence and fluorescence) tomography systems that provide new biological imaging capabilities for especially soft tissues. Some of the major scientific impact the EIC has had is exemplified by 1) the incorporation of quantitative of optical tomography to analyze tumor response and syngeneic tumor models and longitudinally after irradiation with the SARRP; stressing that the risk of missing target using single beam irradiation; and 2) in the last 9 months, they have demonstrated with Monte Carlo computer simulation that it is feasible to use kilovoltage x-ray as typical for the Core to deliver FLASH (50-200 Gy/s) irradiation in a self-shielded cabinet. A plan has been devised to construct the system at the Cancer Center, and it represents the foundation for the new generation of SARRP. The capabilities, unique to Hopkins, will allow research into the many unresolved mechanisms on transformative potential of FLASH.

We utilize advanced 3D printing technology to enhance patient care and treatment outcomes. This innovative approach allows for the precise customization of tools and phantoms, significantly improving the precision and effectiveness of radiation therapy. The 3D printer supports the creation of individualized devices that optimize the delivery of radiation doses for measurements. This technology not only advances clinical practices but also fosters research and development in personalized medical solutions, setting new standards in the field of radiation oncology.

Our main computation facility is Rockfish, which is a community-shared cluster at Johns Hopkins University and housed at Maryland Advanced Research and Computer Center in Baltimore. It follows the “condominium model” with three main units. The first unit is based on an NSF Major Research Infrastructure grant, a second unit contains mainly medium-sodez condos (for example DURIP/DoD, Deans’ contributions condos), and the last unit is a collection of individual research groups condos. All three units are shared, with no physical separation, by all users. Rockfish has 34,128 cores (711 nodes), a combined theoretical performance of 3.3 PFLOPs and Rmax of 2.1 PFLOPs. Rockfish has three parallel file systems (GPFS) with a total of ~13PB of usable space. The Rockfish cluster has Mellanox Infinidad HDR100 connectivity (1:1.5 topology).

Brachytherapy implant quality for gynecologic cancers requires precise placement of interstitial catheters to optimize the dose to patients and maximize therapeutic outcome. At Johns Hopkins, novel magnetic resonance (MR)-tracked stylets have been designed and are being investigated for their capability to provide intraoperative image guidance for clinicians to better guide brachytherapy implants. This technology is also anticipated to limit the need for mid-implant CT and MRI images to assess catheter position, which will reduce overall procedure time.